AXIAL PUMP AND HYDRAULIC DRIVE SYSTEM

Abstract

A hydraulic device having an input shaft and an output shaft, the device comprising: a housing having the input shaft mounted at one end and the output shaft mounted at the other end; an axially reciprocating hydraulic pump mounted on the input shaft within the housing, the axially reciprocating hydraulic pump having: a plurality of pistons located in respective piston bores and configured for axial reciprocation therein; a cam plate connected to the input shaft, the cam plate having a plurality of cam surfaces distributed about the cam plate for driving the plurality of pistons towards Top Dead Center (TDC) of the piston bores; a rotating hydraulic motor mounted on the output shaft within the housing for rotating with the output shaft; and a pair of shared fluid conduits, one of the pair directly and fluidly connecting a fluid outlet of the axially reciprocating hydraulic pump with a fluid inlet of the rotating hydraulic motor and the other of the pair for directly and fluidly connecting a fluid outlet of the rotating hydraulic motor with a fluid inlet of the axially reciprocating hydraulic pump, such that the pair are contained within the housing; wherein flow of hydraulic fluid between the axially reciprocating hydraulic pump and the rotating hydraulic motor bypasses any fluid reservoir external to the housing.

Description

FIELD

The present disclosure relates to piston configurations and hydraulic device configurations

BACKGROUND

Paired hydraulic pumps and motors are used predominantly in industry when mechanical actuation is desired to convert hydraulic pressure and flow into torque and angular (rotation). Examples of hydraulic application can be in braking systems, propulsion systems (e.g. automotive, drilling) as well as in electrical energy generation systems (e.g. windmills). Other common uses of hydraulic devices as a direct drive system can be in drilling rigs, winches and crane drives, wheel motors for vehicles, cranes, and excavators, conveyor and feeder drives, mixer and agitator drives, roll mills, drum drives for digesters, kilns, trench cutters, high-powered lawn trimmers, and plastic injection machines. Further, hydraulic pumps, motors, can be combined into hydraulic drive systems, for example one or more hydraulic pumps coupled to one or more hydraulic motors constituting a hydraulic transmission.

Due to currently available configurations, there exists disadvantages with hydraulic drive systems. One disadvantage is where the motor housing is typically distanced from the pump housing and interconnected via a series of extended hydraulic lines between the corresponding inlets and outlets. The use of hydraulic lines (e.g. hoses) can result in system pressure drop resulting in system inefficiencies. A result of the use of hydraulic hoses is that the longer distances between pump and motor via the intervening fluid lines means slower liquid transfer between the pump and the motor. This can require that the pump be larger than the motor and can require the pump to operate at higher revolutions to offset the pressure drop and provide the motor with the required flow to do the work.

Another disadvantage with currently available hydraulic drive systems is that distanced pump/motor housings can result in pump pistons starvation.

A further disadvantage is that off the shelf hydraulic systems are bulky in design and do not lend themselves easily to applications in compact spaces. As such, the adoption of hydraulic drive systems in energy regeneration has been limited to date. Another disadvantage for currently available hydraulic drive systems is that multiplication of torque at the system output cannot be provided for in an fluidly efficient and compact form factor due to the number of individual hydraulic devices needed to make up a complete system, as well as the multiplicative effects of pressure losses due to the need for interconnecting fluid hoses. A further disadvantage is that changing the rotational direction of the motor in a hydraulic system can require stopping of the pump in order to change the direction of the pump and motor operation, something which is impractical. Current transmissions, including those used with over the road and other commercial applications, it is common for reverse directions to only have one speed as compared to multiple speeds for the forward direction.

In terms of current axial piston pump configurations, there exists mechanical complications in the design and use of variable angle rotating drive plates (i.e. wobble plate). As such, current axial piston pump designs tend to have higher than desired maintenance costs and issues, are considered operationally inefficient as compared to other reciprocating piston pump designs, and more importantly, current axial piston pumps and motors produce vibration/noise (e.g. Fluidborne noise and Structuralborne Noise). Considered by the industry as the two primary, potentially unsolvable and unwanted problems.

SUMMARY

It is an object of the present invention to provide an axial piston pump to obviate or mitigate at least some of the above presented disadvantages.

It is an object of the present invention to provide a hydraulic drive system to obviate or mitigate at least some of the above presented disadvantages.

It is an object of the present invention to provide a hydraulic drive motor to obviate or mitigate at least some of the above presented disadvantages.

A first aspect provided is a hydraulic device having an input shaft and an output shaft, the device comprising: a housing having the input shaft mounted at one end and the output shaft mounted at the other end; an axially reciprocating hydraulic pump mounted on the input shaft within the housing, the axially reciprocating hydraulic pump having: a plurality of pistons located in respective piston bores and configured for axial reciprocation therein; a cam plate connected to the input shaft, the cam plate having a plurality of cam surfaces distributed about the cam plate for driving the plurality of pistons towards Top Dead Center (TDC) of the piston bores; a rotating hydraulic motor mounted on the output shaft within the housing for rotating with the output shaft; and a pair of shared fluid conduits, one of the pair directly and fluidly connecting a fluid outlet of the axially reciprocating hydraulic pump with a fluid inlet of the rotating hydraulic motor and the other of the pair for directly and fluidly connecting a fluid outlet of the rotating hydraulic motor with a fluid inlet of the axially reciprocating hydraulic pump, such that the pair are contained within the housing; wherein flow of hydraulic fluid between the axially reciprocating hydraulic pump and the rotating hydraulic motor bypasses any fluid reservoir external to the housing.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other aspects will now be described by way of example only with reference to the attached drawings, in which:

FIG. 1 is a cross sectional view of a piston cylinder arrangement of a hydraulic drive and driven system;

FIG. 2a is a cross sectional view of a rotating cam plate of the hydraulic drive system shown in FIG. 1;

FIG. 2b is a cross sectional view of the rotating cam plate of the hydraulic drive system shown in FIG. 2a with TDC and BDC considerations;

FIG. 3 is an operational example of the hydraulic drive system shown in FIG. 1;

FIG. 4 is a further operational example of the hydraulic drive system shown in FIG. 1;

FIG. 5 is a still further operational example of the hydraulic drive system shown in FIG. 1;

FIG. 6 is still further operational example of the hydraulic drive system shown in FIG. 1;

FIG. 7 is still further operational example of the hydraulic drive system shown in FIG. 1;

FIG. 8 is still further operational example of the hydraulic drive system shown in FIG. 1;

FIG. 9 is an alternative embodiment of the hydraulic drive system shown in FIG. 1; and

FIG. 10 is an operational example of the hydraulic drive system shown in FIG. 9.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to FIG. 1, shown is a hydraulic device 100 having a housing 242 enclosing an axial hydraulic pump 101 mounted on shaft 25 (e.g. input shaft driven by an electric motor) supported on bearings 102. Further, the housing 242 also contains one or more hydraulic motors 103 (e.g. rotating, vane type) mounted on shaft 24 (e.g. an output shaft connected to a system to do work such as but not limited to a vehicle drive shaft, a wheel spindle, etc.) supported on bearings 105. It is recognised that the shaft 24 is mechanically decoupled from the shaft 25, thus providing for a direct driving fluidly of the hydraulic motor(s) 103 by the hydraulic pump 101 and direct supplying fluidly of the hydraulic pump 101 by the hydraulic motor(s) 103 within the same housing 242, as effected by hydraulic fluid inlet and outlet exchange between the hydraulic pump 101 and the hydraulic motor(s) 103, as further described below. In other words, hydraulic fluid outlet of the hydraulic pump 101 within the housing 242 is directly and fluidly coupled to hydraulic fluid inlet of the hydraulic motor(s) 103 within the housing 242 and hydraulic inlet of the hydraulic pump 101 within the housing 242 is directly and fluidly coupled to hydraulic outlet of the hydraulic motor(s) 103 within the housing 242, such that directly and fluidly coupled is defined as any hydraulic fluid transfer between the hydraulic pump 101 and the hydraulic motor(s) 103 bypasses entry and exit of any intermediate hydraulic fluid reservoir (not shown) external/internal to the housing 242.

In terms of a hydraulic system provided by the hydraulic device 100, including the fluidly coupled hydraulic pumps 101,107 and hydraulic motor(s) 103, pressure of the hydraulic fluid 111 entering the hydraulic pump 101,107 is less than the pressure of the hydraulic fluid 111 exiting the hydraulic pump 101,107 due to work being performed on the hydraulic fluid 111 by the pistons of the hydraulic pump 101,107. Further, it is recognised that pressure of the hydraulic fluid 111 entering the hydraulic motor(s) 103 is greater than the pressure of the hydraulic fluid 111 exiting the hydraulic motor(s) 103 due to work being performed on the mechanical components (e.g. inducing rotation of gears, vanes, etc.) of the hydraulic motor(s) 103 by the hydraulic fluid 111. Further, it is recognised that the pressure of the hydraulic fluid 111 exiting the hydraulic motor(s) 103 and re-entering the inlet of the hydraulic pump 101,107 is at a pressure greater than atmospheric pressure, due to the fact that the direct and fluid coupling (i.e. shared fluid conduits 35a,b) there between is unvented. On the contrary, intermediate hydraulic reservoirs (not shown) of state of the art hydraulic systems are vented to atmosphere and as such, any residual pressure contained in the hydraulic fluid 111 exiting the hydraulic motor(s) 103 is exhausted via the intermediate hydraulic reservoir.

It is recognised that bypassing of an intermediate hydraulic fluid reservoir (e.g. between the respective inlet/outlets of the hydraulic pump 101,107 and motor(s) 103) for hydraulic fluid exchange between the inlets/outlets of the hydraulic pump 101 and the corresponding outlets/inlets of the hydraulic motor(s) 103 provides for numerous operational advantages, as discussed. The hydraulic device 100 can also optionally have a regenerative hydraulic pump 107 having a rotating cam plate 28 mounted on the shaft 24, such that the regenerative hydraulic pump 107 is coupled fluidly to the hydraulic motor(s) 103 and one or more hydraulic fluid accumulators 1,46. For certain operating conditions, it is recognised that the shaft 24 can be the input shaft, for example in regenerative energy applications. It is recognised that the device types of the motors 103 and the pump 101 can be different, such that the axial reciprocating device type of the hydraulic pump 101 is matched with a rotating device type of the hydraulic motor(s) 103, such that the pump 101 and the motor(s) 103 are mounted on separate shafts 25,24.

Also coupled to the housing 242 via appropriate fluid conduits are the high pressure hydraulic fluid accumulator 46 and the low pressure hydraulic fluid accumulator 1, such that resident fluid pressure of hydraulic fluid in the high pressure hydraulic fluid accumulator 46 is greater than resident fluid pressure of hydraulic fluid in the low pressure hydraulic fluid accumulator 1. The high pressure accumulator 46 can be used as a source of high pressure hydraulic fluid 111 that can be channeled through the hydraulic motor(s) 103 and returned to the low pressure accumulator 1 in order to cause rotation of the shaft 24, as further described by example below. The low pressure accumulator 1 can be used to provide priming hydraulic fluid 111 upon start up of the hydraulic device 100 when valve 3 is open to provide hydraulic fluid 111 via line 8 into fluid gallery 9 in order to prime piston bores 11,27 with hydraulic fluid 111. Further, piston bores 108,109 can be primed via fluid gallery 214 with hydraulic fluid 111 from the low pressure accumulator 1 when valve 3 and valve 213 are opened simultaneously. Also provided can be a hydraulic fluid filter 41 as is known in the art. Also provided can be a series of cooling fins 124 to one side of the housing 242 (e.g. adjacent to the shaft 25 of the pump 101 and opposite to the piston bores 108,109 and/or 11,27), in order to provide for thermodynamic cooling of the hydraulic device 100, when in operation, via cooling fluid (e.g. air) circulating into and out of cooling fan 240 (e.g. rotating with shaft 25) via cooling fluid lines 241 (e.g. air passage) of the housing 242.

The axial hydraulic pump 101 has a plurality of axially reciprocating pistons 64,65 driven by a cam plate 29 mounted on the shaft 25, the cam plate having a plurality of cam lobes distributed about the cam plate 29. As the shaft 25 is rotated due to an energy input device coupled to the shaft 25 (e.g. electric motor, internal combustion engine, etc.—not shown), the cam plate 29 with corresponding cam lobes also rotates with the shaft 25 to cause advancing cam surfaces 104 to (via a series of cam lobes) alternately drive the pistons 64,65 towards Top Dead Center (TDC) of the piston bores 11,27 against any fluid pressure of hydraulic fluid 111 present in the piston bores 11,27, thereby facilitating ejection of hydraulic fluid 111 from the piston bores 64,65. Conversely, the pistons 64,65 also travel towards Bottom Dead Center (BDC) of piston bores 64,65 under bias of the hydraulic fluid 111 (under pressure) being injected into the piston bores 64,65, and stored energy returned by passive pistons, such that piston drive faces 106 remain in contact with the retreating cam surfaces 104 as the cam plate 29 is rotated.

As such, in general, the pistons 64,65 reciprocate in respective bores 11,27 as the cam surfaces 104 of respective cam lobes act on piston drive surfaces 106 of the pistons 64,65, in order to drive the pistons 64,65 axially in their respective bores 11,27 towards TDC and to receive the pistons 64,65 as they are forced towards BDC via the injection of hydraulic fluid 111 into the piston bores 11,27. The interface between the cam surfaces 104 and the opposing piston drive surfaces 106 is of a floating type, such that absence of appropriate fluid pressure in the piston bores 11,27 can provide for decoupling (i.e. cam surface 104 is spaced apart in the piston bore(s) 11,27 from the piston drive surface 106) between the cam plate 29 and the pistons 64,65 such that the pistons 64,65 can remain at TDC once positioned there due to rotation of the cam plate 29, or can remain anywhere between BDC and TDC when introduction of hydraulic fluid 111 into the piston bores 11,27 is restricted via operation of appropriate valves as further described below. Optionally, piston bores 11,27 can be subdivided by floating pistons 110 acting as a reciprocating piston interface between hydraulic fluid 111 volume and pressure (considered as an incompressible fluid) and compressible fluid (e.g. air) 112 volume and pressure. The volume of the compressible fluid 112 on one side of the floating piston 110 can be fixed (shown) or variable through an appropriate compressible fluid inlet/outlet port (not shown). It is recognised that pressure of the compressible fluid 112 to one side of the floating piston 110 is dependent upon the volume of the compressible fluid in the piston bore 11,27 as well as the pressure of the hydraulic fluid 111 on the other side of the floating piston 110.

Application of a driving force by the cam surfaces 104 drives the pistons 64,65 towards TDC of the piston bores 11,27 in order to pump hydraulic fluid 111 resident in the bores 11,27 out through fluid gallery 13, such that fluid gallery 13 of piston bore 11 is in direct fluid communication with fluid gallery 13 of piston bore 27. Fluid gallery 13 is considered a fluid outlet for the piston bores 11,27. Further, entry of hydraulic fluid 111 through fluid gallery 9 into piston bores 11,27 of sufficient pressure and volume acts to drive the pistons 64,65 back towards BDC of the piston bores 11,27, such that fluid gallery 9 of piston bore 11 is in direct fluid communication with fluid gallery 9 of piston bore 27. In other words, hydraulic fluid 111 entering into the piston bores 11,27 via common fluid gallery 9 (i.e. hydraulic fluid inlets of the piston bores 11,27) causes the piston drive surfaces 106 to be encouraged to follow the rotating cam surfaces 104 as the axial pistons 64,65 travel back towards BDC. It is also recognised that in the event that the pistons 64,65 are spaced apart from the cam lobes of the cam plate 29, i.e. cam surfaces 104 are out of direct contact with piston drive surfaces 106, introduction of hydraulic fluid 111 into the piston bores 11,27 will drive the pistons 64,65 towards BDC in order to place cam surfaces 104 in direct contact with piston drive surfaces 106. It is recognised that more than two pistons 64,65 and corresponding piston bores 11,27 can be connected to the fluid galleries 9,13, for example multiple pairs of pistons 64,65 and piston bores 11,27 distributed about the input shaft 25 as driven by the rotating cam plate 29.

Optionally, the axial hydraulic pump 101 and/or the regenerative pump 107 can be configured as a double acting pump. Shown is a double acting configuration for the pump 101 as an example, such that each of the pistons 64,65 has a corresponding opposing piston 238,243 as desired, however it is recognisd that the regenerative pump 107 could have pistons and bores with appropriate valving and fluid conduits on the other side of the cam plate 28 similar to the arrangement for the pistons 65,64 on the other side of the cam plate 29. In the double acting configuration, axial pistons 238,243 reciprocate in corresponding piston bores 108,109 when acted upon by the cam lobes of the cam plate 29, such that pistons 238,243 also have piston drive surfaces 106 of a floating type with corresponding cam surfaces 104 as discussed above. As such, the plurality of axially reciprocating pistons 238,243 are driven by the cam plate 29 mounted on the shaft 25, the cam plate having the plurality of cam lobes distributed about the cam plate 29. As the shaft 25 is rotated due to the energy input device coupled to the shaft 25 (e.g. electric motor, internal combustion engine, etc.—not shown), the cam plate 29 with corresponding cam lobes also rotates with the shaft 25 to cause advancing cam surfaces 104 to (via a series of cam lobes) alternately drive the pistons 238,243 towards TDC of the piston bores 108,109 against any fluid pressure of hydraulic fluid 111 present in the piston bores 108,109, thereby facilitating ejection of hydraulic fluid 111 from the piston bores 108,109. Conversely, the pistons 238,243 also travel towards BDC of piston bores 108,109 under bias of the hydraulic fluid 111 and pressure being injected into the piston bores 108,109, such that piston drive faces 106 remain in contact with the retreating cam surfaces 104 as driven by the injection of the hydraulic fluid 111 into the piston bores 108,109 under pressure.

Optionally, piston bores 108,109 can be subdivided by floating pistons 114 acting as a reciprocating piston interface between hydraulic fluid 111 volume and pressure (considered as an incompressible fluid) and compressible fluid (e.g. air) 112 volume and pressure. The volume of the compressible fluid 112 on one side of the floating piston 114 can be fixed (shown) or variable through an appropriate compressible fluid inlet/outlet port (not shown). It is recognised that pressure of the compressible fluid 112 to one side of the floating piston 114 is dependent upon the pressure of the hydraulic fluid 111 on the other side of the floating piston 114. Accordingly, the hydraulic pump 101 configured as a double acting pump can have pairs of opposed pistons 64,238 or 65,243 operated on by a common intervening cam lobe on the rotating cam plate 29, such that the respective pair of cam surfaces 104 of the common can lobe are oriented away from one another. In FIG. 1 the cam surface 104 acting on piston 238 is oriented away from the cam surface 104 acting on piston 64 such that the pair of cam surfaces are directly opposite to one another (e.g. a linear relative orientation or 180 degrees apart). However, it is recognised that this type of cam surface 104 pair orientation shown in FIG. 1 is only by example, as other orientations are possible, such as but not limited to “V” shaped relative orientations, etc. It is recognised that more than two pistons 238,243 and corresponding piston bores 108,109 can be connected to the fluid galleries 214,215, for example multiple pairs of pistons 238,243 and piston bores 108,109 distributed about the input shaft 25 as driven by the rotating cam plate 29.

Application of a driving force by the cam surfaces 104 drives the pistons 238,243 towards TDC of the piston bores 108,109 in order to pump hydraulic fluid 111 resident in the bores 108,109 out through fluid gallery 215, such that fluid gallery 215 of piston bore 108 is in direct fluid communication with fluid gallery 215 of piston bore 109. Fluid gallery 215 is considered a fluid outlet for the piston bores 108,109. Further, entry of hydraulic fluid 111 through fluid gallery 214 into piston bores 108,109 of sufficient pressure and volume acts to drive the pistons 238,243 back towards BDC of the piston bores 108,109, such that fluid gallery 214 of piston bore 108 is in direct fluid communication with fluid gallery 214 of piston bore 109. In other words, hydraulic fluid 111 entering into the piston bores 108,109 via fluid gallery 214 (i.e. hydraulic fluid inlets of the piston bores 108,109) causes the piston drive surfaces 106 to follow the rotating cam surfaces 104 as the axial pistons 238,243 travel back towards BDC. It is also recognised that in the event that the pistons 238,243 are spaced apart from the cam lobes of the cam plate 29, i.e. cam surfaces 104 are out of direct contact with piston drive surfaces 106, introduction of hydraulic fluid 111 into the piston bores 108,109 will drive the pistons 238,243 towards BDC in order to place cam surfaces 104 in direct contact with piston drive surfaces 106.

As such, it is recognised that optionally the rotating cam plate 29 can have pairs of opposed cam surfaces 104 for each of the cam lobes of the cam plate 29 in order to provide for double acting axial reciprocation of opposed pairs of pistons 64,238 and opposed pairs of pistons 65,243. Preferably each piston of the opposed pairs of pistons 64,238 and opposed pairs of pistons 65,243 travel towards TDC or BDC at the same time, e.g. piston 64 travels to TDC as piston 238 travels to TDC and piston 64 travels to BDC as piston 238 travels to BDC in their respective piston bores 11,108. As discussed, the orientation of the opposed pairs of pistons 64,238 and opposed pairs of pistons 65,243 can be other as shown, i.e. other than directly and linearly opposed, for example opposed in a “V” shape configuration using opposing cam faces 104 and/or opposing piston drive faces 106 that are non parallel to one another. A cam lobe can be defined as a portion of the cam plate 28,29 forming the cam face 104 between successive troughs on the cam plate 28,29.

As such, the opposed pairs of pistons 64,238 and 65,243 are positioned on opposite sides of the cam plate 29, as shown in FIG. 2a, such that piston bores 11,27 and 108,109 are omitted for clarity. Referring to FIG. 2b, shown are the advancing and retreating cam faces 104 interacting with the piston drive faces 106 of the pistons 64,65,238,243, resulting in axial displacement of the pistons 64,65,238,243 in the respective piston bores 111,27,108,109 between TDC and BDC (i.e. advancing towards TDC and retreating towards BDC) as the piston drive faces 106 follow the cam faces 104 during axial reciprocation of the pistons 64,65,238,243 in the respective piston bores 111,27,108,109. It is also recognised that cam plate 28, with respect to pistons 116,118 and faces 104,106, operates in a similar manner to that shown in FIGS. 2a,2b for cam plate 29.

The regenerative hydraulic pump 107 has the rotating cam plate 28 mounted on the shaft 24 with a plurality of axially reciprocating pistons 116,118 driven by the cam plate 28 as it rotates. The pistons 116,118 reciprocate in respective bores 119,120 as the cam surfaces 104 of respective cam lobes act on piston drive surfaces 106 of the pistons 116,118, in order to drive the pistons 116,118 axially in their respective bores 119,120. The interface between the cam surfaces 104 and the opposing piston drive surfaces 106 is of a floating type, such that absence of appropriate fluid pressure in the piston bores 119,120 can provide for decoupling (i.e. cam surface 104 is spaced apart in the piston bore(s) 119,120 from the piston drive surface 106) between the cam plate 28 and the pistons 116,118 such that the pistons 116,118 can remain at TDC once positioned there due to rotation of the cam plate 28, or can remain somewhere between TDC and BDC once the inflow of hydraulic fluid 111 into the piston bores 119,120 is inhibited via appropriate operation of valves restricting access of the hydraulic fluid 111 into the piston bores 119,120. Optionally, piston bores 119,120 can be subdivided by floating pistons 122 acting as a reciprocating piston interface between hydraulic fluid 111 volume and pressure (considered as an incompressible fluid) and compressible fluid (e.g. air) 112 volume and pressure. The volume of the compressible fluid 112 on one side of the floating piston 122 can be fixed (shown) or variable through an appropriate compressible fluid inlet/outlet port (not shown). It is recognised that pressure of the compressible fluid 112 to one side of the floating piston 122 is dependent upon the volume of the compressible fluid in the piston bore 119,120 as well as the pressure of the hydraulic fluid 111 on the other side of the floating piston 122.

The axial regenerative hydraulic pump 107 has the plurality of axially reciprocating pistons 116,118 driven by the cam plate 28 mounted on the shaft 24, the cam plate having the plurality of cam lobes distributed about the cam plate 28. As the shaft 24 is rotated (e.g. by rotation of a vehicle wheel connected to the shaft 24), the cam plate 28 with corresponding cam lobes also rotates with the shaft 24 to cause advancing cam surfaces 104 to (via a series of cam lobes) alternately drive the pistons 116,118 towards TDC of the piston bores 119,120 against any fluid pressure of hydraulic fluid 111 present in the piston bores 119,120, thereby facilitating ejection of hydraulic fluid 111 from the piston bores 119,120. Conversely, the pistons 116,118 also travel towards BDC of piston bores 119,120 under bias of the hydraulic fluid 111 and pressure being injected into the piston bores 119,120, such that piston drive faces 106 remain in contact with the retreating cam surfaces 104 as the cam plate 28 rotates. It is recognised that more than two pistons 116,118 and corresponding piston bores 119,120 can be connected to the fluid galleries 16,19, for example multiple pairs of pistons 116,118 and piston bores 119,120 distributed about the output shaft 24 as driven by the rotating cam plate 28. It is also recognised that the number of pistons 116,118 need not match the number of pistons 64,65.

Application of a driving force by the cam surfaces 104 drives the pistons 116,118 towards TDC of the piston bores 119,120 in order to pump hydraulic fluid 111 resident in the bores 119,120 out through fluid gallery 19, such that fluid gallery 19 of piston bore 119 is in direct fluid communication with fluid gallery 19 of piston bore 120. Fluid gallery 19 is considered a fluid outlet for the piston bores 119,120. Further, entry of hydraulic fluid 111 through fluid gallery 16 into piston bores 119,120 of sufficient pressure and volume acts to drive the pistons 116,118 back towards BDC of the piston bores 119,120, such that fluid gallery 16 of piston bore 119 is in direct fluid communication with fluid gallery 16 of piston bore 120. In other words, hydraulic fluid 111 entering into the piston bores 119,120 via fluid gallery 16 (i.e. hydraulic fluid inlets of the piston bores 119,120) causes the piston drive surfaces 106 to follow the retreating cam surfaces 104 as the axial pistons 116,118 travel back towards BDC. It is also recognised that in the event that the pistons 116,118 are spaced apart from the cam lobes of the cam plate 28, i.e. cam surfaces 104 are out of direct contact with piston drive surfaces 106, introduction of hydraulic fluid 111 into the piston bores 119,120 will drive the pistons 116,118 towards BDC in order to place cam surfaces 104 in direct contact with piston drive surfaces 106.

The housing 242 contains one or more hydraulic motors 103 (e.g. rotating, vane type) mounted on the shaft 24, such that injection/ejection of hydraulic fluid 111 into/out of shared fluid conduits 35a,35b provides for pressure and flow induced rotation of the hydraulic motors 103. The shared fluid conduits 35a,35b in the housing 242 are positioned between the inlets/outlets of the hydraulic pump 101,107 and the hydraulic motor 103, such that the fluid transfer between the hydraulic pump 101,107 and the hydraulic motor(s) 103 is such that they are directly fed by one another via the interposed shared fluid conduits 35a,35b (i.e. pressurized fluid 111 ejected from the pump 101,107 is fed to the motor(s) 103 and expired fluid 111 from the motor(s) 103 is supplied to the pump 101,107). As such, respective inlets/outlets of the hydraulic pump 101 (optionally the regenerative hydraulic pump 107) and the hydraulic motor(s) 103 are directly and fluidly coupled by the shared fluid conduits 35a,b positioned there between. In other words, the shared fluid conduits 35a,35b can accept hydraulic fluid 111 from the fluid outlet 13,19 of the hydraulic pump(s) 101,107 and feed the received hydraulic fluid 111 directly to the fluid inlet (via opened valve(s) 218,219,220,223,222,221) of the hydraulic motor(s) 103, such that any intermediate fluid reservoir (not shown) is bypassed in transference of the hydraulic fluid 111 between the hydraulic motor(s) 103 and the hydraulic pump 101,107 performed via the shared fluid conduits 35a,b.

As well, the shared fluid conduits 35a,35b can accept hydraulic fluid 111 from the fluid outlet (via appropriately opened valve(s) 218,219,220,223,222,221) of the hydraulic motors(s) 103 and feed the received hydraulic fluid 111 directly to the fluid inlet 9,16 of the hydraulic pump(s) 101,107, such that an intermediate fluid reservoir is bypassed in transference of the hydraulic fluid 111 between the hydraulic motor(s) 103 and the hydraulic pump 101,107 performed via the shared fluid conduits 35a,b. As such, each shared fluid conduit 35a,35b has an entrance for accepting hydraulic fluid 111 from the corresponding fluid outlet of one of the hydraulic motor 103 or the hydraulic pump 101,107 and an exit coupled to the corresponding fluid inlet for delivering the hydraulic fluid 111 from the shared fluid conduit 35a,b into the corresponding fluid inlet of the other of the hydraulic motor 103 or the hydraulic pump 101,107. It is recognised that the shared fluid conduit 35a,b is not considered a fluid reservoir as the shared fluid conduit 35a,b contains pressurized hydraulic fluid 111 of the same pressure as hydraulic fluid 111 exiting the hydraulic pump 101,107 or hydraulic motor(s) 103. It is also recognised that injection pressure control of the hydraulic fluid 111 exiting the hydraulic motor(s) 103 is controlled via pressure control valve 167 before introduction of the hydraulic fluid 111 to the inlet gallery 9,214 of the hydraulic pump 101,107. As such, it is recognised that injection pressure control is implemented between the shared fluid conduits 35a,b for fluid flowing from the hydraulic motor(s) 103 towards the hydraulic pump 101,107, such that the pressure of the hydraulic fluid 111 is greater than atmospheric in order to facilitate a greater operational efficiency of the hydraulic device 100 as compared to state of the art systems involving vented fluid reservoirs positioned between the outlets of a hydraulic motor and an inlet of a hydraulic pump coupled to the hydraulic motor.

It is also recognised that utilization of the shared fluid conduits 35a,b positioned within the housing 242 provides for a reduced length of fluid conduit extending between both the inlet/outlet and the outlet/inlet of the hydraulic pump 101,107 and motor(s) 103 respectively, as compared to state of the art hydraulic systems involving supply lines between respective housings of the pump and the motor, thus facilitating an advantage of the hydraulic device 100 providing reduced hydraulic circuit losses and fluid transit lag as compared to the state of the art hydraulic systems.

A further advantage is that pressure losses, due to cooling provided by external reservoirs used in state of the art hydraulic systems, is inhibited on the hydraulic device 100 due to implementation of the cooling fins 241 provided in the body of the housing 242, such that heat transfer for heat generated in the hydraulic fluid 111 is by first transfer to the body (e.g. metal block) of the housing 242 from the hydraulic fluid 111 and then second from the body to atmosphere by the cooling fins 241 and associated cooling fan 240. It is also recognised that instead of air used for cooling, fins 241 and fan 240 could be exposed to cooling fluid (e.g. water). Any heat transfer by state of the art hydraulic systems typically involves a heat exchanger that is coupled to the external reservoir, which is separate from the individual housings of the pump and motor. As such, heat transfer from the hydraulic fluid for state of the art hydraulic systems relies upon transfer between the fluid and a heat exchanger separate from the individual housings, as compared to the hydraulic device 100 which has the cooling fins 241 (e.g. heat exchanger) in the body of the housing 242 in order to take advantage of heat transfer from the hydraulic fluid 111 to the material of the housing 242 body, as the hydraulic fluid 111 flows within the housing 242 between the hydraulic pump 101,107 and the hydraulic motor(s) 103. Thus it is considered that the hydraulic device 100, as configured with shared fluid conduits 35a,b and cooling fins 241 provided by the body of the housing 242 (e.g. as formed by the body of the housing 242), provides for increased efficiency advantages in fluid flow and heat transfer characteristics as compared to state of the art hydraulic systems involving an intermediate fluid reservoir external to the housings of the hydraulic pump and motor.

It is recognised that a fluid reservoir found in conventional hydraulic systems, i.e. other than the hydraulic device 100, is a reservoir containing fluid that is at a reduced pressure (e.g. vented to atmosphere) compared to the exit pressure or entrance pressure of the hydraulic pump/motor connected to the fluid reservoir. In a typical reservoir of hydraulic systems, fluid is stored in the reservoir, drawn out of the reservoir by a pump at a low pressure and operated on, and dumped into the reservoir by a motor into a fluid pressure dictated by venting requirements of the reservoir. It is also recognised that typical reservoirs are used for heat transfer considerations, i.e. fluid when resident in the reservoir is subjected to cooling (e.g. via a designated direct/indirect heat exchanger and/or surface cooling). It is also recognised that reservoirs are exactly that, reservoirs. As such the exact fluid entering is not immediately expelled from the reservoir upon entry of the subsequent fluid dumped into the reservoir. As such, fluid when deposited into the reservoir mixes with other fluid already contained in the reservoir and then the fluid experiences a latency period (e.g. reservoir residence time) within the reservoir before being withdrawn from the reservoir. Also, given the excess volume capacity of the reservoir as compared to the volume of fluid deposits or withdrawals from the bores of hydraulic devices (e.g. pumps/motors) connected to the reservoir, fluid residency practically guarantees that fluid first in will not be fluid first out of the reservoir. As such, the configuration of the hydraulic fluid outlet 13,19 directly to the fluid inlet of the hydraulic motor(s) 103 via the shared fluid conduit 35a,b, with the fluid outlet of the hydraulic motor(s) 103 directly connected to the fluid inlet 9,16 of the hydraulic pump 101,107, provides for distinct advantages of efficiency and compactness of design as compared to more traditional hydraulic systems having an intervening reservoir between their pump and motor. Further, it is recognised that exit/outlet pressure of the hydraulic fluid 111 from the hydraulic pump 101,107 can be the same, ignoring any frictional pressure losses for intervening valves/fluid conduits between the inlets/outlets, as the entrance/inlet pressure of the hydraulic fluid 111 to the hydraulic motor(s) 103 due to the configuration and position of the shared fluid conduits 35a,b with respect to the hydraulic pump 101,107 and motor(s) 103. Similarly, it is recognised that exit/outlet pressure of the hydraulic fluid 111 from the hydraulic motor 103 can be the same, ignoring any frictional pressure losses for intervening valves/fluid conduits between the inlets/outlets, as the entrance/inlet pressure of the hydraulic fluid 111 to the hydraulic pump 101,107 due to the configuration and position of the shared fluid conduits 35a,d with respect to the hydraulic pump 101,107 and motor(s) 103.

It is appreciated that the fluid outlet gallery 13 of the hydraulic pump 101 feeds into the shared fluid conduit 35a or 35b depending upon whether valve 43 or valve 33 (e.g. of solenoid type) is open or closed, for example open valve 43 and closed valve 33 (as shown) provides outlet gallery 13 to feed shared fluid conduit 35a by the pump 101, while closed valve 43 and open valve 33 (not shown) provides outlet gallery 13 to feed shared fluid conduit 35b by the pump 101, as further discussed below. In terms of the regenerative pump 107, open valve 15 simultaneously with open valve 43 and closed valve 33 (as shown) provides for feeding of the shared fluid conduit 35a by the regenerative pump 107, as further discussed below.

Each motor 103 of the one or more hydraulic motors 103 has a control valve 218,219,220 for providing transfer (ingress or egress) of hydraulic fluid between the shared fluid conduit 35a and each motor 103. For example, if shared conduit 35a is filled with hydraulic fluid 111 by the hydraulic pump 101,107, then opening of control valve 218 will provide hydraulic fluid 111 under pressure to drive motor A. Similarly, opening of control valve 219 will provide hydraulic fluid 111 under pressure to drive motor B. Similarly, opening of control valve 220 will provide hydraulic fluid 111 under pressure to drive motor C. Also recognised that opening of more than one of the control valves 218,219,220 simultaneously will provide for multiple motors A,B,C at once to be driven by the flow of hydraulic fluid 111 entering and the directly exiting the shared fluid conduit 35a. For example, if shared conduit 35b is filled with hydraulic fluid 111 by the hydraulic pump 101,107, then opening of control valve 223 will provide hydraulic fluid 111 under pressure to drive motor A. Similarly, opening of control valve 222 will provide hydraulic fluid 111 under pressure to drive motor B. Similarly, opening of control valve 221 will provide hydraulic fluid 111 under pressure to drive motor C. Also recognised that opening of more than one of the control valves 223,222,221 simultaneously will provide for multiple motors A,B,C at once to be driven by the flow of hydraulic fluid 111 entering and the directly exiting the shared fluid conduit 35b. It is recognised that the entry of hydraulic fluid 111 via valve(s) 218,219,220 provides for rotation of the motor(s) 103 in a first direction (e.g. clockwise), while entry of hydraulic fluid 111 via valve(s) 221,222,223 provides for rotation of the motor(s) 103 in second direction opposite to the first (e.g. counter clockwise). As such the hydraulic motor(s) 103 of the hydraulic device 100 can be driven in a forward or a reverse direction and as such rotation of the shaft 24 can also be driven in a first rotational direction or a second rotational direction opposite to the first rotational direction. These two opposite rotational directions provides for the hydraulic motor(s) 103 to be operated in a forward or reverse direction (e.g. meaning able to propel a vehicle in a forward or reverse direction when the shaft 24 is connected to a drive shaft of the vehicle, meaning able to propel a drill bit in a forward or reverse direction when the shaft 24 is connected to a drive shaft of the drill, etc). As such, the hydraulic device 100 can be operated having one or more motors 103 in operation to drive the output shaft 24, based on the number of valve pairs 218,223 219,222, 220,221 in an open state. In order for each of the motors A,B,C to remain lubricated during operation of the motor 103, each of the valves 218,219,220 or 221,222,223 can be opened at least a fraction in order to provide for some leakage hydraulic fluid flow through each of the motors A,B,C “isolated” from the operational mode of the hydraulic device. For example, if motor A is used in operation of the motor 103, then valve 218 is opened (e.g. fully) and then “unused” motors B,C (which are rotating in conjunction with rotation of Motor A) can be fed via a percentage opening of the valves 219, 220 (e.g. 0.9% open), in order to provide for motors B,C to remain lubricated during rotation of the output shaft 24.

The number of motors 103 selected for operation can depend upon demand considerations of a load (e.g. drive shaft for a drill rig, drive shaft for a motor vehicle, etc.) connected to the output shaft 24, such that increased torque requirements of the load could demand a greater number of the motors 103 in operation as compared to increased speed requirements of the load could demand a lesser number of the motors 103 in operation. In other words, as the torque requirement of the load increases, the number of motors 103 in operation could increase (i.e. more valve pairs 218,223 219,222, 220,221 are opened in response to an increased torque requirement received from the controller 90). In other words, as the torque requirement of the load decreases, the number of motors 103 in operation could decrease (i.e. more valve pairs 218,223 219,222, 220,221 are closed in response to a decreased torque requirement received from the controller 90).

It is recognised that the various control valves can be automatic as pressure driven (e.g. check valves such as those valves in FIG. 1 shown between piston bore 11,27 and fluid galleries 9,13, between shared fluid conduits 35a,b, between piston bores 108,109 and fluid galleries 214, 215 and between piston bores 119,120 and fluid galleries 16,19) and/or can be electronically controlled valves (e.g. valves 3, 15, 33, 43, 54, 59, 213, 218, 219, 220, 221, 222, 223, 234, 235, 236, 237, 238) controlled by the electronic controller 90 (e.g. containing a processor and memory to execute a set of stored instructions to operate the control valves in sequence to effect operation of the hydraulic device 100 for flow of hydraulic fluid 111 to and from the hydraulic motor(s) 103, to and from the hydraulic pump 101,107, and to and from the low pressure accumulator 1 and to and from the high pressure accumulator 46) as providing electronic signals 92 to cause a change in operational state of the control valves, e.g. from valve close to valve open or from valve open to valve close in response to receipt of the control signal). As such, operation of the hydraulic device 100 is effected by operation of the valves as shown. It is also recognised that directed flow of the hydraulic fluid 111 into and out of the selected fluid conduits 8, 38, 39, 42, 44, 60, 61, 69, 77 is used to determine the manner in which the hydraulic fluid 111 enters and exits the shared fluid conduits 35a,b as well as the accumulators 1,46, as directed by the operational state of the valves as discussed herein.

Referring to FIGS. 1 and 3, side A of the main pump using reciprocation of pistons 64,65 in bores 11,27 to drive the hydraulic motor 103. At step 300, valves 3, 43, 54, 59 are opened by the controller 90 sending open signals 92, while valves 4, 237, 213, 15, 33, 55, 236, 235, 234, 246, 250, 252, 254, 256 are held or otherwise operated closed by the controller 90. In terms of motor 103 selection, at least one of the valve pairs 218,223, 219,222, 220,221 are opened by the controller 90 via signals 92 in order to facilitate hydraulic fluid 111 flow into and out of the selected hydraulic motor(s) A,B,C via shared fluid conduits 35a,b. Once the valves are set by the controller 90, this provides for, at step 302, hydraulic fluid 111 to be released from the low pressure accumulator 1 along conduit 8 and into fluid inlet gallery 9 in order to prime the piston bores 11,27. At step 304, reciprocation of input shaft 25 rotates cam plate 29 to cause the advancing cam surfaces 104 to drive pistons 64,65 to pump hydraulic fluid 111 out of piston bores 11,27 via fluid outlets gallery 13 and into shared conduit 35a, as the pistons 64,65 approach TDC, via open solenoid valve 43. At step 306, hydraulic fluid 111 deposited into shared fluid conduit 35a enters one or more selected hydraulic motor(s) A,B,C and causes the output shaft 24 to rotate in a first direction (e.g. forward direction for a vehicle, drill bit, etc. attached to the output shaft 24). At step 308, hydraulic fluid deposited into shared conduit 35b after doing work via the selected hydraulic motor(s) A,B,C enters fluid conduit 39 through valve 54, then through conduit 61, through fluid filter 41, into conduit 77 and through valve 59 in order to access and enter fluid inlet gallery 9, realizing that the injection pressure of the hydraulic fluid into the fluid galleries 9 is regulated by a pressure control valve (PCV) 167 in fluid conduit 69 which facilitates excess hydraulic fluid to be deposited from fluid conduit 69 and back to the shared conduit(s) 35a,b via fluid conduits 49 and 50 coupled thereto. Check valves in fluid conduit 50 provide for entrance of the hydraulic fluid 111 into the shared conduits 35a,b. At step 310, hydraulic fluid entering piston bores 11,27 force the pistons 64,65 against the cam faces 104 to then follow the retreating cam surface 104 as the cam plate rotates on shaft 25 as the pistons 64,65 travel back towards BDC of the piston bores 11,27. At step 312, continued rotation of the input shaft 25 causes the above described circulation of the hydraulic fluid 111 to repeat to continue to operate the selected hydraulic motor(s) A,B,C. It is recognised that since valve 213 is closed, side B of the main pump (i.e. pistons 238,243) remains unprimed and thus piston drive face 106 becomes decoupled from cam faces 104 in the piston bores 108,109 as the cam plate 29 rotates, thus inhibiting injection/ejection of hydraulic fluid 111 with respect to the piston bores 108,109 as the input shaft 25 rotates. Similarly, since valve 15 is closed, the regenerative pump 107 (i.e. pistons 116,118) remains fluidly isolated from the shared conduits 35a,b and thus piston drive face 106 becomes decoupled from cam faces 104 of rotating cam plate 28 in the piston bores 119,120 as the cam plate 28 rotates on the output shaft 24, thus inhibiting injection/ejection of hydraulic fluid 111 with respect to the piston bores 119,120 as the output shaft 24 rotates.

Referring again to FIG. 3, in the event that the double acting ability of the hydraulic device 100 is desired, controller 90 sends open actuation signal 92 to valve 213 to be open at step 400, thus providing for hydraulic fluid 111 at step 314 to be released from the low pressure accumulator 1 along conduit 8 and into fluid inlet gallery 214 in order to prime the piston bores 108,109 as well as piston bores 11,27, thus providing for a double acting hydraulic pump operation. Further at step 304, reciprocation of input shaft 25 rotates cam plate 29 to cause the advancing cam surfaces 104 to drive pistons 238,243 to pump hydraulic fluid 111 out of piston bores 108,109 via fluid outlets gallery 215, into fluid conduits 216, 60, deposited into fluid inlet gallery 9 and then into shared conduit 35a via piston bores 11,27, as the pistons 238,243 also approach TDC, via open solenoid valve 43. Step 306 is done as per above to have at step 316 hydraulic fluid be deposited from conduit 77, into fluid gallery 9 and then via open valve 213 in fluid conduit 8 in order to access and enter fluid inlet gallery 214 of side B, realizing that the injection pressure of the hydraulic fluid into the fluid galleries 214 is regulated by a pressure control valve (PCV) 167 in fluid conduit 69. At step 318, hydraulic fluid 111 also entering piston bores 108,109 when returning from the motor(s) A,B,C force the pistons 238,243 against the cam faces 104 to then follow the retreating cam surface 104 as the cam plate rotates on shaft 25 as the pistons 238,243 travel back towards BDC of the piston bores 108,109. At step 312, continued rotation of the input shaft 25 causes the above described circulation of the hydraulic fluid 111 to repeat to continue to operate the selected hydraulic motor(s) A,B,C under the influence of the double acting configuration of the hydraulic pump 101 (i.e. using both sides A and B of the main pump 101) in order to rotate the output shaft 24.

Referring to FIGS. 1 and 4, side A of the main pump using reciprocation of pistons 64,65 in bores 11,27 to drive the hydraulic motor 103. At step 400, valves 3, 33 55, 59, 54, 256 are opened by the controller 90 sending open signals 92, while valves 4, 237, 213, 15, 43, 236, 235, 246, 250, 252, 254, 234, are held or otherwise operated closed by the controller 90. In terms of motor 103 selection, at least one or more of the valve pairs 218,223, 219,222, 220,221 are opened by the controller 90 via signals 92 in order to facilitate hydraulic fluid 111 flow into and out of the selected hydraulic motor(s) A,B,C via shared fluid conduits 35a,b. Once the valves are set by the controller 90, this provides for, at step 402, hydraulic fluid 111 to be released from the low pressure accumulator 1 along conduit 8 and into fluid inlet gallery 9 in order to prime the piston bores 11,27. At step 404, reciprocation of input shaft 25 (in a same shaft 25 direction as for rotation of the motor(s) A,B,C as described above) rotates cam plate 29 to cause the advancing cam surfaces 104 to drive pistons 64,65 to pump hydraulic fluid 111 out of piston bores 11,27 via fluid outlets gallery 13 and into shared conduit 35b, as the pistons 64,65 approach TDC, via open solenoid valve 33 opposite to closed solenoid valve 43. At step 406, hydraulic fluid 111 deposited into shared fluid conduit 35b enters one or more selected hydraulic motor(s) A,B,C and causes the output shaft to rotate in a second direction opposite the first direction (e.g. reverse direction for a vehicle, drill bit, etc. attached to the output shaft 25). At step 408, hydraulic fluid 111 deposited into shared conduit 35a after doing work via the selected hydraulic motor(s) A,B,C enters fluid conduit 38 through valve 55, then through conduit 62, through fluid filter 41, into conduit 77 and through valve 59 in order to access and enter fluid inlet gallery 9, realizing that the injection pressure of the hydraulic fluid into the fluid galleries 9 is regulated by a pressure control valve (PCV) 167 in fluid conduit 69 which facilitates excess hydraulic fluid to be deposited from fluid conduit 69 and back to the shared conduit(s) 35a,b via fluid conduits 49 and 50 coupled thereto. At step 410, hydraulic fluid 111 entering piston bores 11,27 force the pistons 64,65 against the cam faces 104 to then follow the retreating cam surface 104 as the cam plate rotates on shaft 25 as the pistons 64,65 travel back towards BDC of the piston bores 11,27. At step 412, continued rotation of the input shaft 25 causes the above described circulation of the hydraulic fluid 11 to repeat to continue to operate the selected hydraulic motor(s) A,B,C. It is recognised that since valve 213 is closed, side B of the main pump (i.e. pistons 238,243) remains unprimed and thus piston drive face 106 becomes decoupled from cam faces 104 in the piston bores 108,109 as the cam plate 29 rotates, thus inhibiting injection/ejection of hydraulic fluid 111 with respect to the piston bores 108,109 as the input shaft 25 rotates. Similarly, since valve 15 is closed, the regenerative pump 107 (i.e. pistons 116,118) remains fluidly isolated from the shared conduits 35a,b and thus piston drive face 106 becomes decoupled from cam faces 104 of rotating cam plate 28 in the piston bores 119,120 as the cam plate 28 rotates on the output shaft 24, thus inhibiting injection/ejection of hydraulic fluid 111 with respect to the piston bores 119,120 as the output shaft 24 rotates.

Referring again to FIG. 4, in the event that the double acting ability of the hydraulic device 100 is desired, controller 90 sends open actuation signal 92 to valve 213 to be open at step 400, thus providing for hydraulic fluid 111 at step 414 to be released from the low pressure accumulator 1 along conduit 8 and into fluid inlet gallery 214 in order to prime the piston bores 108,109 as well as piston bores 11,27 via gallery 9, thus providing for a double acting hydraulic pump operation for operating the motor(s) A,B,C in the second direction. Further at step 404, reciprocation of input shaft 25 rotates cam plate 29 to cause the advancing cam surfaces 104 to drive pistons 238,243 to pump hydraulic fluid 111 out of piston bores 108,109 via fluid outlets gallery 215, into fluid conduits 216,60, deposited into fluid inlet gallery 9 and then into shared conduit 35b via piston bores 11,27, as the pistons 238,243 also approach TDC, via open solenoid valve 33. Step 406 is done as per above to have at step 416 hydraulic fluid be deposited from conduit 77, into fluid gallery 9 and then via open valve 213 in fluid conduit 8 in order to access and enter fluid inlet gallery 214 of side B, realizing that the injection pressure of the hydraulic fluid into the fluid galleries 214 is regulated by a pressure control valve (PCV) 167 in fluid conduit 69. At step 418, hydraulic fluid 111 also entering piston bores 108,109 when returning from the motor(s) A,B,C force the pistons 238,243 against the cam faces 104 to then follow the retreating cam surface 104 as the cam plate rotates on shaft 25 as the pistons 238,243 travel back towards BDC of the piston bores 108,109. At step 412, continued rotation of the input shaft 25 causes the above described circulation of the hydraulic fluid 111 to repeat to continue to operate the selected hydraulic motor(s) A,B,C under the influence of the double acting configuration of the hydraulic pump 101 (i.e. using both sides A and B of the main pump 101) in order to rotate the output shaft 24 in the second direction.

As per above, it is recognised that operation of the hydraulic motor(s) A,B,C, in both the forward (a first direction) and the reverse (in a second direction opposite the first direction) rotational directions, is facilitates by selecting one or more motor(s) A,B,C from a cluster of motors contained in the hydraulic motor 103. In other words, simulation of a hydraulic transmission in both forward and reverse directions can be accommodated for by the hydraulic device 100 based on selection of the appropriate valving (e.g. one or the other of the solenoid valves 43,33 to facilitate the shared conduits 35a,b being used in an 35a to 35b or a 35b to a 35a direction) along with the appropriate number of motors A,B,C via selection of one or more valve pairs 218,223, 219,222, 220,221 opened by the controller 90 via signals 92. In other words, opening of multiple valve pairs 218,223, 219,222, 220,221 simultaneously provides for multiple motors A,B,C to be operated (i.e. rotated) at the same time based on the same flow of hydraulic fluid 111 provided from and to the hydraulic pump 101 via the shared fluid conduits 35a,b. It is also recognised that open/close state of the pair of solenoid valves 43,33 provides for either: 1) using the shared fluid conduit 35a as the motor 103 fluid inlet and the shared fluid conduit 35b as the motor 103 fluid outlet; or 2) the shared fluid conduit 35b as the motor 103 fluid inlet and the shared fluid conduit 35a as the motor 103 fluid outlet. Swapping use of the shared fluid conduits 35a,b as either inlets or outlets provides the advantage of operating the hydraulic motor(s) A,B,C in either the first direction or the second direction to provide for corresponding rotation of the output shaft 24 in either the first direction or the second direction, while the input shaft 25 maintains its rotation in the same direction for both the first direction or the second direction of the output shaft 24.

Referring to FIGS. 1 and 5, regenerative pump 107 using reciprocation of pistons 116,118 in bores 119,120 to drive the hydraulic fluid 111 from the low pressure accumulator 1 to the high pressure accumulator 46. At step 500, valves 4, 15, 54, 55, 234, 236, 256 are opened by the controller 90 sending open signals 92, while valves 3, 213, 237, 235, 48, 43, 33, 59, 167, 246, 252, 250, 254 are held or otherwise operated closed by the controller 90. Once the valves are set by the controller 90, this provides for, at step 502, hydraulic fluid 111 to be released from the low pressure accumulator 1 along conduit 44 and into fluid inlet gallery 16 via valve 15 in order to prime the piston bores 119,120, thereby forcing pistons 116,118 towards BDC. At step 504, as the pistons 116,118 travel towards BDC, piston drive faces 106 act against cam surface 104 in piston bores 119,120. At step 506, reciprocation of output shaft 24 (in view of mechanical/kinetic energy input from vehicle wheels attached to the output shaft, etc.) rotates cam plate 28 to cause the advancing cam surfaces 104 to drive pistons 116,118 to pump hydraulic fluid 111 out of piston bores 119,120 via fluid outlet gallery 19 and into shared conduit 35a,b via fluid conduit 38, as the pistons 116,118 approach TDC at step 506 (noting fluid isolation of main hydraulic pump 101 maintained via closed solenoid valve 33 opposite to closed solenoid valve 43 and check valves on the outside of gallery 13). Also it is noted that the hydraulic motors A,B,C are isolated from the hydraulic circuit, however hydraulic fluid 111 still has access to either side 35a,b of the hydraulic motors A,B,C via fluid conduit 38 and associated check valves in order to keep the motors A,B,C lubricated as the output shaft 24 is rotated. At step 508, hydraulic fluid 111 deposited into shared fluid conduit 35a,b bypasses one or more selected hydraulic motor(s) A,B,C and flows out through valves 54,55 and into fluid conduit 77, such that in regenerative mode, all solenoid valves relating to motors A,B,C in-out flow should be left open so that all motors A,B,C get lubricated. At step 510, hydraulic fluid 111 enters fluid conduit 69 and through valve 236 in order to be deposited into the high pressure accumulator 46. Thus continued injection of hydraulic fluid 111 at step 512 from the low pressure accumulator 1 into the regenerative pump 107 repeats at step 502 in order to use continued mechanical/kinetic energy transferred to shaft 24 (via external mechanical system such as rotating vehicle wheels—not shown—connected to the shaft 24) acting as an input shaft under energy regeneration conditions (e.g. using momentum of the vehicle connected to the shaft 24 to pump hydraulic fluid 111 from the low pressure accumulator 1 to the high pressure accumulator 46), while operation of main pump 101 and the motors A,B,C remains fluidly isolated from the hydraulic circuit as per above (i.e. are isolated from doing work on the hydraulic fluid as the hydraulic fluid is circulated through the regenerative pump 107 in travelling from the low pressure accumulator 1 to the high pressure accumulator 46.

Referring to FIGS. 1 and 6, driving the hydraulic motor 103 is performed while the regenerative pump 107 and the main pump 101,103 remain fluidly isolated whereby respective cam faces 104 and opposed piston drive faces 106 can become decoupled. At step 600, valves 48, 54, 235, 237, 256 are opened by the controller 90 sending open signals 92, while valves 236, 43, 33, 15, 55, 59, 167, 234, 3, 426, 250, 252, 254, 213, 4 are held or otherwise operated closed by the controller 90. In terms of motor 103 selection, at least one or more of the valve pairs 218,223, 219,222, 220,221 are opened by the controller 90 via signals 92 in order to facilitate hydraulic fluid 111 flow into and out of the selected hydraulic motor(s) A,B,C via shared fluid conduits 35a,b. Once the valves are set by the controller 90, this provides, at step 602, hydraulic fluid 111 to be released from the high pressure accumulator 46 as stored energy and into and out of the motor A,B,C via through open valve 48, into conduit 42, and into shared fluid conduit 35a. At step 604, hydraulic fluid 111 deposited into shared fluid conduit 35a enters one or more selected hydraulic motor(s) A,B,C and causes the motor(s) A,B,C to rotate in order to drive the attached output shaft 24. At step 606, hydraulic fluid 111 is deposited into shared conduit 35b after doing work via the selected hydraulic motor(s) A,B,C and enters fluid conduit 39 through valve 54, through fluid conduit 61, through filter 41, into conduits 77,69 and through valves 235,237 in order to be deposited into the low pressure accumulator 1. At step 608, continued supply of hydraulic fluid out of the HP accumulator 46 provides for continued rotation of the output shaft 24 via stored energy release, thus transferring from the HP accumulator 46 to the LP accumulator 1.

Referring to FIGS. 1 and 7, driving the hydraulic motor 103 is performed, while only the regenerative pump 107 and side B of the main pump 101 remain fluidly isolated whereby respective cam faces 104 and opposed piston drive faces 106 can become decoupled. At step 700, valves 43, 54, 48, 59, 235, 237, 3, 4, 256 (note 167 can also be used at this time to control the injection pressure into the main pump 101) are opened by the controller 90 sending open signals 92, while valves 3, 15, 33, 55, 234, 236, 213, 246, 250, 252, 254, are held or otherwise operated closed by the controller 90. In terms of motor 103 selection, at least one or more of the valve pairs 218,223, 219,222, 220,221 are opened by the controller 90 via signals 92 in order to facilitate hydraulic fluid 111 flow into and out of the selected hydraulic motor(s) A,B,C via shared fluid conduits 35a,b. Once the valves are set by the controller 90, this provides for, at step 702, hydraulic fluid 111 primes pistons 64,65 of the main pump A as per above along with travel into and out of the motor(s) A,B,C as per steps 302,304,306,308,310,312 of FIG. 3. Simultaneously at step 704, fluid travels from the HP accumulator 46 through the motor(s) A,B,C to the LP accumulator 1 as per steps 602,604,608 of FIG. 6. It is also recognised that the injection pressure of the hydraulic fluid 111 into the fluid galleries 9 is regulated by the pressure control valve (PCV) 167 in fluid conduit 69 which facilitates excess hydraulic fluid to be deposited from fluid conduit 69 and back to the shared conduit(s) 35a,b via fluid conduits 49 and 50 coupled thereto. It is also recognised that some of the flowing hydraulic fluid 111 will remain within the motor pump circuit (via shared fluid conduits 35a,b) while any excess volume of the hydraulic fluid 111 is directed to the LP accumulator 1 via conduit 69 and valves 235, 237.

Referring to FIGS. 1 and 7, driving the hydraulic motor 103 is performed, while only the regenerative pump 107 remains fluidly isolated whereby respective cam faces 104 and opposed piston drive faces 106 can become decoupled. At step 700, valves 3, 43, 54, 48, 59, 213, 235, 237, 256 (note 167 can also be used at this time to control the injection pressure into the main pump 101) are opened by the controller 90 sending open signals 92, while valves 15, 33, 55, 234, 236, 246, 250, 252, 254, are held or otherwise operated closed by the controller 90. In terms of motor 103 selection, at least one or more of the valve pairs 218,223, 219,222, 220,221 are opened by the controller 90 via signals 92 in order to facilitate hydraulic fluid 111 flow into and out of the selected hydraulic motor(s) A,B,C via shared fluid conduits 35a,b. Once the valves are set by the controller 90, this provides for, at step 706 for operating the side B pump (e.g. double acting mode) is done simultaneously with steps 702 and 704. Sub steps 314, 316,318 are performed in step 706 as described above for FIG. 3. It is also recognised that the injection pressure of the hydraulic fluid 111 into the fluid galleries 9 is regulated by the pressure control valve (PCV) 167 in fluid conduit 69 which facilitates excess hydraulic fluid to be deposited from fluid conduit 69 and back to the shared conduit(s) 35a,b via fluid conduits 49 and 50 coupled thereto. It is also recognised that some of the flowing hydraulic fluid 111 will remain within the motor pump circuit (via shared fluid conduits 35a,b) while any excess volume of the hydraulic fluid 111 is directed to the LP accumulator 1 via conduit 69 and valves 235,237.

Referring to FIGS. 1 and 8, storing energy during engine idle of a mechanical system (e.g. Internal Combustion Engine idle connected to input shaft 25) is performed, while only the regenerative pump 107 and side B of the main pump 101 remain fluidly isolated (noting the motors A,B,C can also be isolated given there is no rotation of same) whereby respective cam faces 104 and opposed piston drive faces 106 can become decoupled. At step 800, valves 3, 234, 235, 236 are opened by the controller 90 sending open signals 92, while valves 237, 213, 48, 33, 43, 15, 59, 4, 54, 55, 250, 252, 254, 256, 246 are held or otherwise operated closed by the controller 90. Once the valves are set by the controller 90, this provides for, at step 802, hydraulic fluid 111 to be released from the low pressure accumulator 1 along conduit 8 and into fluid inlet gallery 9 in order to prime the piston bores 11,27. At step 804, reciprocation of input shaft 25 rotates cam plate 29 to cause the advancing cam surfaces 104 to drive pistons 64,65 to pump hydraulic fluid 111 out of piston bores 11,27 via fluid outlets gallery 13 and into fluid conduit 44 (bypassing shared conduit 35a as valves 43,33 are close in order to fluidly isolate hydraulic motor(s) A,B,C), as the pistons 64,65 approach TDC. At step 806, hydraulic fluid 111 enters into the HP accumulator 46 via open valves 234,235,236. At step 808, repeated injection of hydraulic fluid 111 at step 802 causes continued transfer via the main pump A of hydraulic fluid 111 from the LP accumulator 1. It is also recognised that the pressure of the hydraulic fluid 111 is regulated by the pressure control valve (PCV) 167. It is noted that injection pressure can also be regulated by valve 3 which could be a PCV for example.

Referring to FIGS. 1 and 8, storing kinetic energy during idle of a mechanical system (e.g. Internal Combustion Engine idle connected to input shaft 25) is performed, while only the regenerative pump 107 remains fluidly isolated (and also isolation of the motors A,B,C) whereby respective cam faces 104 and opposed piston drive faces 106 can become decoupled. At step 800, valves 3, 213, 234, 235, 236 are opened by the controller 90 sending open signals 92, while valves 237, 15, 33, 43, 48, 4, 59, 54, 55, 256, 246, 250, 252, 254 are held or otherwise operated closed by the controller 90 and 167 controls injection pressure. Once the valves are set by the controller 90, this provides for, at step 810 hydraulic fluid 111 to be released from the low pressure accumulator 1 along conduit 8 and into fluid inlet gallery 9 as well as into fluid gallery 214 in order to prime the piston bores 108,109 along with piston bores 11,27, thus providing for double acting operation. At step 812 in conjunction with step 804, reciprocation of input shaft 25 rotates cam plate 29 to cause the advancing cam surfaces 104 to drive pistons 238,243 to pump hydraulic fluid 111 out of piston bores 108,109 via fluid outlets gallery 215 and into fluid conduit 216 and into fluid inlet gallery 9 via piston bores 11,27 to fluid outlet gallery 13 and into fluid conduit 44 (bypassing shared conduit 35a,b as valves 43,33 are closed in order to fluidly isolate hydraulic motor(s) A,B,C), as the pistons 238,243 approach TDC. At step 806, hydraulic fluid 111 enters into the HP accumulator 46 via open valves 234,235,236. At step 808, repeated injection of hydraulic fluid 111 at step 802 causes continued transfer via the pump A,B of main pump 101 of hydraulic fluid 111 from the LP accumulator 1. It is also recognised that the pressure of the hydraulic fluid 111 is regulated by the pressure control valve (PCV) 167 and 3.

It is recognised that filling of the HP accumulator 46 during engine idle conditions provides for the hydraulic device 100 to output some storable energy while using the idling engine or the like. This storage ability at idle is also an advantage as it allows for the HP accumulator 46 to be filled towards capacity and then used as stored energy combined with the continuous energy obtained from normal operation of the hydraulic pump 101 and hydraulic motor 103 to provide a momentary power boost at the motor output shaft 24, when desired as controlled by the controller 90.

Referring to FIGS. 1 and 9 and 10, controller 90 via signals 92 can select which of the pistons 238,243 and/or 64,65, and/or 116,118 are used to assist in braking of the vehicle (not shown) connected to the output shaft 24 (e.g. drive shaft and/or wheel spindles) and optionally connected to the input shaft 25 (e.g. coupled to an engine—e.g. ICE—of the vehicle). As such in this example, the engine or power plant of the vehicle is used to drive the vehicle wheels under normal operation (or track system in the case of a track vehicle) in order to propel the vehicle along a surface (e.g. roadway, railway tracks, etc.) supporting the vehicle. As such, the first rotational direction of the output shaft 24 can be referred to as a forward direction for the vehicle and the second rotational direction can be referred to as a reverse direction of the vehicle.

The hydraulic device 100 can also have a fluid conduit 245 associated with a pressure control valve 246 connected to the fluid circuit of the hydraulic device 100 between the valve 236 and the HP accumulator 46. Pressure control/relief valve 246 operates such that when input pressure of the hydraulic fluid 111 reaches a predetermined maximum pressure when passing through valve 236, this is an indication that the HP accumulator 46 is considered full and cannot accept any more hydraulic fluid 111. As such, once the HP accumulator 46 becomes filled (e.g. cannot accept any further hydraulic fluid 111), utilization of the hydraulic device 100 to provide braking horsepower for the vehicle is as provided below where hydraulic fluid flowing through valve 236 is directed through the pressure control valve 246 and into fluid conduit 245 directing hydraulic fluid away from the HP accumulator 46. It is recognized that when pressure in accumulator 46 reaches a predetermined maximum, valve 236 may not see max pressure from the system as there needs to be a head to have pressure as discussed.

The fluid conduit 245 is coupled to fluid conduit 77 via valve 250, to fluid conduit 60 via control valve 252 and to fluid inlet gallery 16 via control valve 254. Positioned in series with fluid conduit 245 can be a fluid cooler lines CL1 and/or a fluid cooler lines CL2 (e.g. (e.g. heat transfer device provided by the fins 241 in the body of the housing 242 as acted upon by the cooling fan 240), used to extract heat from the hydraulic fluid 111 flowing through the pressure control valve 246 introduced due to a pressure drop experienced by the hydraulic fluid 111 when passing there through, i.e. temperature of the hydraulic fluid 111 on the inlet side of the pressure control valve 246 is lower than the temperature of the hydraulic fluid 111 on the outlet side of the pressure control valve 246. Also provided is a control valve 256 in fluid conduit 69.

In terms of facilitating engine braking (i.e. use of hydraulic pump 101 coupled to input shaft 25) in combination with regenerative braking (i.e. use of regenerative pump 107 coupled to the output shaft 24), pistons 64,65 and pistons 238,243 can be employed in the hydraulic device 100 to perform work on the hydraulic fluid 111, thus transferring potential engine brake HP from the engine of the vehicle via the input shaft 25 along with output shaft 24 brake HP in the form of heat generation via the pressure control valve 246. In order to implement this braking mode, a linkage 240 (see FIG. 1) can be engaged by the control unit 90 (via an engagement signal) between the input 25 and output 24 shafts, such that engagement of the linkage 240 results in a coupling (e.g. mechanical, hydraulic, etc.) between the shafts 24,25 to facilitate their co-rotation. Once the braking mode is completed (e.g. braking is no longer required), the control unit can send a disengagement signal to the linkage 240 in order to decouple the shafts 24,25. It is recognized that that the linkage 240 can be configured to have the shafts 24,25 co-rotate at the same RPM or can be configured to have the shafts 24,25 co-rotate at different RPMs. In any event, it is recognized that coupling of the shafts 24,25 together by linkage 240 effectively puts the engine in direct communication with any load connected to the output shaft 24 (e.g. wheels). One example is a mechanical linkage 240 optionally involving one or more gears, such that the mechanical clutch linkage 240 can be engaged by the control unit 90 to couple the shafts 24,25 to one another or can be disengaged by the control unit 90 to decouple the shafts 24,25 to one another. One example is a hydraulic clutch linkage 240, such that the hydraulic clutch linkage 240 can be engaged by the control unit 90 to couple the shafts 24,25 to one another or can be disengaged by the control unit 90 to decouple the shafts 24,25 to one another. It is recognized that a normal operating mode of the hydraulic unit 100 can be where the shafts 24,25 are decoupled from one another, except in the case of braking as described.

This type of braking can be for a less sustained or shorter term braking, such as desiring a decrease in speed of the vehicle due to a slow down or stop event (e.g. braking due to potential collision, braking to stop, etc.), recognizing that the use of the regenerative pump 107 as part of the hydraulic circuit provides for lubrication of the hydraulic motors A,B,C while isolating the hydraulic motors A,B,C in terms of performing work on the hydraulic fluid 111 (see description associated with FIG. 5 above). Referring to FIG. 10, at step 900, valves 4,15,234,236,246,256,54,55,254 are opened by the controller 90 sending open signals 92, while valves 3,252,43,33,59,48,250,213,235,237 are held or otherwise operated closed by the controller 90. As such, the controller 90 is used to select the main A pump and the regenerative pump 107 to circuit the hydraulic fluid 111 while isolating the main B pump and the hydraulic motor(s) 103 from the hydraulic circuit used in circulating hydraulic fluid 111 through the fluid conduit 245. As such, at step 902 a load such as an engine coupled to the input shaft 25 along with the load (e.g. wheels) connect to the output shaft 24 is used to provide for engine braking via transfer of engine power transmitted through input shaft 25 with load/wheel braking via output shaft 24 into heat via circulation of the hydraulic fluid 111 through the pressure control valve 246 and into fluid conduit 245. At steps 904 and 912, hydraulic fluid 111 is circulated through the cooling lines CL1,CL2 to dissipate the generated heat from the hydraulic fluid 111. At steps 906 and 914 the hydraulic fluid 111 is circulated through valve 252 and back into the fluid inlet gallery 9 of the main pump A for further operation by the pistons 64,65 and into the fluid inlet gallery 16 of the regenerative pump 107 for further operation by the pistons 116,118 and circulation back through the pressure control valve 246.

In terms of facilitating engine braking (i.e. use of hydraulic pump 101 coupled to input shaft 25) in combination with regenerative braking (i.e. use of regenerative pump 107 coupled to the output shaft 24), pistons 64,65 and pistons 238,243,116,118 can be employed in the hydraulic device 100 to do work on the hydraulic fluid 111, thus transferring potential engine brake HP from the engine of the vehicle via the input shaft 25 along with output shaft 24 brake HP in the form of heat generation via the pressure control valve 246. In order to implement this braking mode, a linkage 240 (see FIG. 1) can be engaged by the control unit 90 (via an engagement signal) between the input 25 and output 24 shafts, such that engagement of the linkage 240 results in a coupling (e.g. mechanical, hydraulic, etc.) between the shafts 24,25 to facilitate their co-rotation. Once the braking mode is completed (e.g. braking is no longer required), the control unit can send a disengagement signal to the linkage 240 in order to decouple the shafts 24,25. This type of braking can be for a less sustained or shorter term braking, such as desiring a greater decrease in speed of the vehicle due to a slow down or stop event (e.g. braking due to potential collision, braking to stop, etc.), recognizing that the use of the regenerative pump 107 as part of the hydraulic circuit provides for lubrication of the hydraulic motors A,B,C while isolating the hydraulic motors A,B,C in terms of performing work on the hydraulic fluid 111 (see description associated with FIG. 5 above). Referring to FIG. 10, at step 900, valves 4,15,54, 55, 246, 256, 254, 234, 236 are opened by the controller 90 sending open signals 92, while valves 3,33, 43, 48, 59, 250, 213, 237, 252, 235 are held or otherwise operated closed by the controller 90. As such, the controller 90 is used to select the main A pump and the main B pump and the regenerative pump 107 to circulate the hydraulic fluid 111 while isolating the main B pump and the hydraulic motor(s) 103 from the hydraulic circuit used in circulating hydraulic fluid 111 through the fluid conduit 245. As such, at step 902 a load such as an engine coupled to the input shaft 25 along with the load (e.g. wheels) connect to the output shaft 24 is used to provide for engine braking via transfer of engine power transmitted through input shaft 25 with load/wheel braking via output shaft 24 into heat via circulation of the hydraulic fluid 111 through the pressure control valve 246 and into fluid conduit 245. At steps 904 and 912, hydraulic fluid 111 is circulated through the cooling lines CL1,CL2 to dissipate the generated heat from the hydraulic fluid 111. At steps 906 and 914 the hydraulic fluid 111 is circulated through valve 252 and back into the fluid inlet gallery 9 of the main pump A and into the fluid inlet gallery 214 of the main pump B for further operation by the pistons 64,65,238,243 and into the fluid inlet gallery 16 of the regenerative pump 107 for further operation by the pistons 116,118 and circulation back through the pressure control valve 246.

In terms of facilitating wheel or track braking (i.e. use of hydraulic pump 107 coupled to output shaft 24), pistons 116,118 can be employed in the hydraulic device 100 to do work on the hydraulic fluid 111, thus transferring wheel brake HP from the wheels of the vehicle via the output shaft 24 to the hydraulic fluid 111 in the form of heat generation via the pressure control valve 246. In order to implement this braking mode, a linkage 240 (see FIG. 1) can be disengaged between the input 25 and output 24 shafts, such that disengagement of the linkage 240 results in a decoupling between the shafts 24,25 to facilitate their co-rotation. This type of braking can be for a more sustained or longer term braking, such as driving at a somewhat constant speed (but not limited to) by the vehicle down a decline. Referring to FIG. 10, at step 900, valves 4,15,234,236,246,55,54,256,254 are opened by the controller 90 sending open signals 92, while valves 43, 33, 59, 48, 250, 213, 235, 237, 3, 252 are held or otherwise operated closed by the controller 90. As such, the controller 90 is used to select the regenerative pump 107 to flow the hydraulic fluid 111, maintaining lubrication of the hydraulic motor(s) 103, while isolating the hydraulic pump 101 (i.e. decoupling driving of pistons 64,65,238,243 from the input shaft 25) from the hydraulic circuit used in circulating hydraulic fluid 111 through the fluid conduit 245. As such, at step 910 the load such as an wheels coupled to the output shaft 24 is used to provide for wheel braking via transfer of wheel power transmitted through output shaft 24 into heat via circulation of the hydraulic fluid 111 through the pressure control valve 246 and into fluid conduit 245. At step 912, the hydraulic fluid 111 is circulated through the cooling lines CL1,CL2 to dissipate the generated heat from the hydraulic fluid 111, while realizing that any fluid entering and exiting the motor(s) 103 is deposited into the fluid conduit 245, such that valves 246, 250 are off to force flow up fluid conduit 69 past 256, 236 and finally 246. At step 914 the hydraulic fluid 111 is circulated through valve 254 and back into the fluid inlet gallery 16 of the regenerative pump 107 for further operation by the reciprocating pistons 116,118, and circulation back through the pressure control valve 246 via fluid outlet gallery 19 and fluid conduit 42 through control valve 48.

In view of the above, it is recognised that the controller 90 can configure via selection of appropriate valving whether to engage: 1) load on the shafts 24, 25 for generating and dissipating heat via the hydraulic fluid 111 circulation to effect load (e.g. engine and wheels) braking via a single/double acting use of the main pump 101 and the regenerative pump 107; and 2) load on the output shaft 24 for generating and dissipating heat via the hydraulic fluid 111 circulation to effect load (e.g. wheel) braking via a the regenerative pump 107.

It is recognized that the linkage 240 can be used in a number of modes other than in the braking modes as discussed above. It is recognized that the linkage 240 is positioned between the two cam plates 28,29 in order to couple the shafts 24,25 to one another for co-rotation. One advantage for engagement of the linkage 240 is for connecting the engine (via input shaft 25) as direct mechanical connection to the load (e.g. wheels) via the output shaft 24. Once engaged, the valves as provided above can be operated by the controller 90 to isolate (from the hydraulic circuit) operation of the main pump 101 and/or the regenerative pump 107 while the shafts 24,25 are directly coupled via the linkage 240. This provides for driving of the output shaft 24 directly via the input shaft 25, for example in the event of pump 101, 107 failure (or one of the hydraulic lines coupled thereto). Another advantage is in the case where the accumulator 46 becomes full and thus the load of the engine coupled to the input shaft 25 can be used. One advantage here is that the hydraulic circuit can be used to provide a portion of the brake horsepower and the engine can be used to provide the other portion of the brake horsepower during vehicle braking events. It is recognized that once the operation involving coupling of both shafts 24,25 is completed, the controller 90 can disengage (i.e. decouple) the linkage 240 via the signals as desired.

Claims

1. A hydraulic device having an input shaft and an output shaft, the device comprising:

a housing having the input shaft mounted at one end and the output shaft mounted at the other end;

an axially reciprocating hydraulic pump mounted on the input shaft within the housing, the axially reciprocating hydraulic pump having: a plurality of pistons located in respective piston bores and configured for axial reciprocation therein; a cam plate connected to the input shaft, the cam plate having a plurality of cam surfaces distributed about the cam plate for driving the plurality of pistons towards Top Dead Center (TDC) of the piston bores;

a rotating hydraulic motor mounted on the output shaft within the housing for rotating with the output shaft; and a pair of shared fluid conduits, one of the pair directly and fluidly connecting a fluid outlet of the axially reciprocating hydraulic pump with a fluid inlet of the rotating hydraulic motor and the other of the pair for directly and fluidly connecting a fluid outlet of the rotating hydraulic motor with a fluid inlet of the axially reciprocating hydraulic pump, such that the pair are contained within the housing; wherein flow of hydraulic fluid between the axially reciprocating hydraulic pump and the rotating hydraulic motor bypasses any fluid reservoir external to the housing.

2. The device of claim 1, wherein the cam plate is connected to the input shaft at a fixed angle to the input shaft.

3. The device of claim 1, wherein the other of the pair is fluidly connected to a second fluid conduit connecting the other of the pair to the fluid inlet of the hydraulic pump, the second fluid conduit located within a shell of the housing between the fluid inlet of the hydraulic pump and the fluid outlet of the hydraulic motor.

4. The device of claim 1, wherein the fluid inlet of the hydraulic pump and the fluid outlet of the hydraulic motor are located within the shell of the housing.

5. The device of claim 1, wherein each of the cam surfaces is opposite to a respective drive piston surface of each of the plurality of pistons, such that the cam surfaces and the drive piston surfaces can become decoupled from one another in a spaced apart manner based on an amount of the hydraulic fluid contained within the piston bores.

6. The device of claim 1, wherein the amount of the hydraulic fluid injected into a selected piston bore of the piston bores can be inhibited via closing of a valve associated with a fluid line connected to the fluid inlet of the selected piston bore in order to inhibit axial reciprocation of the piston in the selected piston bore while maintaining an open state of a second valve associated with a second fluid line connected to the fluid inlet of a second piston bore of the piston bores in order to maintain axial reciprocation of a second piston in the second piston bore.

7. The device of claim 1, further comprising a second set of pistons located in a second set piston bores and configured for axial reciprocation therein, second set of pistons opposed to the plurality of pistons to provide for configuration of the hydraulic pump as a double acting pump, such that the cam plate has a second set of cam surfaces distributed about the cam plate opposite the plurality of cam surfaces, the second set of cam surfaces for driving the plurality of pistons towards TDC of the second set of piston bores, fluid outlets of the second set of piston bores fluidly coupled to the one of the pair and fluid outlets of the second set of piston bores fluidly coupled to the other of the pair.

8. The device of claim 1, further comprising a set of control valves for inhibiting injection of the hydraulic fluid into the fluid inlets of the second set of piston bores to provide for operation of the hydraulic pump as a single acting pump.

9. The device of claim 1, further comprising a third set of pistons positioned in a corresponding set of piston bores in the housing a cam plate connected to the input shaft, the cam plate having a plurality of cam surfaces distributed about the cam plate for driving the plurality of pistons towards Top Dead Center (TDC) of the piston bores.

10. The device of claim 1, wherein the output shaft and the input shaft are decoupled from one another and thus free to rotate independently with respect to one another.

11. The device of claim 1, further comprising a linkage for coupling the output shaft to the input shaft to facilitate a braking mode.