MULTI-CLUSTER GEAR DEVICE
A multi-cluster gear device operable to function as a pump, a motor or operable to alternate between a pump and a motor.
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The invention relates to a multi-cluster gear device and more particularly to a multi-cluster gear hydraulic device that can operate as a pump or motor.
BACKGROUND OF THE INVENTIONIn general, gear pumps and motors use a combination of two gears as a mechanical device to cooperate with the transfer of fluid between one fluid inlet to one fluid outlet of the device. In order to do mechanical work, gear motors receive pressurized oil which flows around the gears. The pressurized oil cannot flow through the gears at the point where they are meshed and therefore the oil flows around the outside of each of the gears causing the gears to rotate and therefore work. Accordingly, power obtained from the flow of hydraulic fluid through the hydraulic gear device is transferred to rotational power of the shaft connected to one of the gears, thus providing for a gear motor that transforms hydraulic fluid power into rotational power. Alternatively, hydraulic gear devices are often used in hydraulic fluid power applications such as in transmissions, power steering and engines, such that power obtained from rotation of a shaft connected to one of the gears is transferred to fluid power causing the flow of hydraulic fluid through the pump from the fluid inlet to the fluid outlet, thus providing for a gear pump that transforms rotational shaft power into hydraulic fluid power. It is recognized that hydraulic gear devices can be external gear devices, in which the gears are both external, or internal gear devices, in which one gear is external and one is internal.
Gear pumps work on the principal of positive displacement. This means that a constant amount of fluid is pumped during each gear revolution. In general, as the meshed gears in a gear pump rotate they create a low and a high pressure side. Which side is which is determined by the gear rotational direction. Fluid is drawn into the low pressure side, or intake side, of the pump. The fluid is carried by the gears, to the discharge side of the pump. As the gears connect, or mesh, at the discharge side, the fluid is displaced and leaves the pump.
Traditional gear pumps use a pair of gears to draw and deliver fluid between one fluid inlet and one fluid outlet, such that the fluid output is dependent on the size and rotational speed of the gears. In order to deliver a higher output flow of fluid, higher shaft RPM, larger gears or more pumps (e.g. in parallel) are required. However, increasing the number of pumps can increase the number of independent components being used which can result in having more parts that may require maintenance and/or replacement, as well as increased space and weight requirements. Alternatively, the size of the working gears may be increased to increase the output flow, however, this can present a challenge if space is limited, as well as present inertia issues for changing pump speeds. As well, higher rotational speeds can result in higher operational temperatures and overall increased friction and associated costs.
Further, shifting of gear alignments (e.g. axially, laterally) within the housing of the gear pump, during higher hydraulic loadings, can cause undesirable damage (e.g. abrasive wearing of surface material) to the inside surface of the gear housing and/or the gear teeth themselves, as gap tolerances between the gear teeth and the housing inside surface are minimized (e.g. to within one thousandth of an inch) to inhibit hydraulic fluid blow-by from the high pressure side to the low pressure side of the pump. In particular, removal of the surface material due to wear can also increase the gap distance between the gear teeth and the housing inside surface, which can result in decreased pumping efficiency due to increased blow-by of hydraulic fluid from the high pressure side of the pump to the low pressure side of the pump. Further, excessive tension forces can be experienced by fasteners used to assemble multi-piece housings, due to high fluid pressures, which can result in fastener failure and/or undesirable increases in predefined tolerance gaps within a gear cavity of the device.
SUMMARY OF THE INVENTIONIt is therefore desired to provide a gear pump and/or motor that is capable of providing variable output flow while using a number of gears that is not equal to the number of hydraulic fluid ports.
It is an object of the present invention to provide for a hydraulic gear device that has greater number of fluid ports communicating with a gear cavity than the number of gears positioned within the gear cavity.
It is an object of the present invention to provide for a hydraulic gear device that obviates or mitigates at least one of the above-presented disadvantages.
The present invention provides a multi-cluster gear device.
In one embodiment, the multi-cluster gear device comprises a shaft rotatable about a longitudinal axis, a primary gear mounted on the shaft, at least two secondary gears spaced about and positioned to engage with the primary gear, each of the at least two secondary gears configured to independently receive fluid from a fluid reservoir and to allow flow of a portion of the fluid about the secondary gear and to allow the remaining portion of the fluid to be carried by the primary gear to the adjacent secondary gear.
In a further embodiment, the multi-cluster gear device includes at least two secondary gears, the secondary gears being smaller than the primary gear. In a further embodiment the at least two secondary gears are spaced evenly about the periphery of the primary gear.
In a further embodiment, 50% of the fluid received by each of the at least two secondary gears flows around respective secondary gears and the remaining 50% is carried to the adjacent secondary gear by the primary gear.
In a further embodiment, each of the secondary gears is independently fluidly connected to a fluid inlet and a fluid outlet. In one embodiment, each of the secondary gears is configured to receive fluid at low pressure through the fluid inlet.
In one embodiment, each of the secondary gears is configured to release fluid at high pressure through the fluid outlet.
In an alternative embodiment, the multi-cluster gear device includes three secondary gears. In another embodiment, the multi-cluster gear devices includes four secondary gears.
The present invention will now be described in further detail with reference to the following figures:
The present invention provides a multi-cluster hydraulic gear device that includes a main gear (e.g. a large gear) fluidly connected to at least two secondary gears (e.g. a first small gear and a second small gear). Each gear cluster, i.e. the mechanical meshed connection between adjacent gears (e.g. of the main gear with the secondary gear), is fluidly connected to an adjacent gear cluster (e.g. connection of the main gear with the other secondary gear) and is able to, in one working mode, defer 50% of the drawn fluid to the downstream secondary gear (e.g. second small gear) while also receiving 50% from the upstream secondary gear (e.g. first small gear).
The present invention will now be described in further detail with reference to
The present invention provides a multi-cluster hydraulic gear device that includes a main drive gear, also referred to herein as a large or primary gear, and at least two additional secondary gears (e.g. each smaller than the main gear). In one embodiment, fluid is drawn into a low pressure cavity of the device where it is split into two or more parts. One follows the rotation of one of the secondary gears into the high pressure cavity of the same cluster while a second part of the flow follows the rotation of the main gear into the high pressure side of the next nearest cluster (between the next secondary gear and the main gear) as per the main gear's rotation direction. The multi-cluster hydraulic gear device is able to operate in a working (e.g. full flow) mode and also in a by-pass mode, both modes are discussed further below.
The multi-cluster hydraulic gear device can include a ring gear, or large gear, having internal or external teeth, that is supported within a housing. One or more spur gears, or pinion gears, also referred to herein as small/secondary gears, include external teeth, that are sized to mesh with the teeth of the large gear. For a main gear having internal teeth, each of the secondary gears is located internally of the main gear. For a main gear having external teeth, each of the secondary gears is located externally of the main gear. The teeth on each secondary gear are sized to mesh with the teeth on the main gear. Rotation of the main gear will initiate rotation of each of the secondary gears, and vice versa, i.e. each of the gears can be driving or can be driven. It is recognized that the main gear can be of a diameter greater than any one or all of the secondary gears. It is recognized that the main gear can be of a diameter smaller than any one or all of the secondary gears. It is recognized that the main gear can be of the same diameter as any one or all of the secondary gears.
Due the presence of two or more secondary gears, each of these gears acts as a gear device (e.g. pump or motor), also referred to as a gear cluster, due to the individual interaction of each secondary gear with its respective portion of the main gear as a respective gear cluster of the multi-gear cluster. Accordingly, it is recognized that the multi-cluster hydraulic gear device 20 contains multiple gear devices (e.g. pump or motor) within a common housing, such that each of the gear devices contributes a respective portion of the total hydraulic fluid output of the multi-cluster hydraulic gear device 20. It is also recognized that each gear device of the multi-cluster hydraulic gear device 20 can have a pair of hydraulic ports (e.g. an inlet port and an outlet port) associated therewith, such that each port communicates hydraulic fluid between an exterior of a gear cavity containing the multiple gear devices and the interior of the gear cavity. This configuration of ports can result in a greater number of fluid ports communicating fluid to and from the gear cavity than the number of actual gears positioned within the gear cavity. In one embodiment, there can be a pair of hydraulic ports associated with each of the secondary gears, however it is recognized that there can be more than two ports per secondary gear in the case of multi-port configurations. For example, each secondary gear can have two inlet ports and two outlet ports associated therewith, as desired. Alternatively, the number of inlet ports and outlet ports per secondary gear can be unequal (e.g. an inlet port with a pair of outlet ports or a pair of inlet ports with an outlet port).
Turning to
The configuration of the individual gears used within the multi-cluster hydraulic gear device 20 will now be described. Turning now to
The rotational direction of the main gear 22 and the secondary gears 24A, 24B, is shown by the arrows in
In operation of the multi-cluster hydraulic gear device 20 of
Turning to
In an alternative embodiment, shown in
The multi-cluster hydraulic gear device 20 is housed in a housing, identified at numeral 42 in
Also shown is a input shaft 44 of the multi-cluster hydraulic gear device 20 which accepts or delivers rotational torque to the main gear 22. The device 20 may also include a shaft seal 47, as well as other seals (not shown) as part of the housing 42, to withstand low pressure and retain hydraulic fluid within the device housing 42. It will be understood that the multi-cluster hydraulic gear device 20, when used as a gear pump, may also include additional components such as an input shaft 46, for connection to a rotational energy source via the device input shaft 44, i.e. torque, a clutch 48 (see
For example, as seen in the figure, the portion (e.g. 50%) of the fluid that is drawn into the low pressure side, shown at 1A, of the top secondary gear 24-1, is carried around the secondary gear 24-1 and is carried over to 1B. The remaining portion (e.g. 50%) is carried over to 2B by the main gear 22 where it joins with portion (e.g. 50%) that has passed around the small secondary 24-2 to result in port output total (e.g. 100%) at the high pressure side 2B. The inlet fluid drawn by 2A, see arrows at 2A, is divided into two parts by the related gear cluster device 23, i.e. the secondary gear 24-2 and the main gear 22. Portion (e.g. 50%) of the drawn fluid follows the secondary gear 24-2 around to the high pressure side 2B, as indicated by the direction of the arrow around the secondary gear, where it combines with the portion (e.g. 50%) from secondary gear 24-1, as discussed above. The other portion (e.g. 50%) is carried by the main gear 22 over to the high pressure side of the adjacent secondary gear 24-3, indicated at 3B. Likewise, inlet fluid is drawn by 3A, see arrows at 3A, and is divided into two parts by the related gear cluster device 23, i.e. the secondary gear 24-3 and the main gear 22. Portion (e.g. 50%) of the drawn fluid follows the secondary gear 24-3 around to the high pressure side 3B, as indicated by the direction of the arrow around the secondary gear 24-3, where it combines with the portion (e.g. 50%) received via the main gear 22 from secondary gear 24-2. The other portion (e.g. 50%) is carried by the main gear 22 over to the high pressure side of the adjacent secondary gear 24-4, indicated at 4B. The fluid flow at secondary gear 24-4 is as per the above. Fluid is drawn in at low pressure side 4A. Of this inlet fluid, portion (e.g. 50%) is carried by secondary gear 24-4 around to the high pressure side 4B, where it merges with the portion (e.g. 50%) received from secondary gear 24-3. The remaining portion (e.g. 50%) is carried by main gear 22 to the high pressure side 1B of secondary gear 24-1 to combine with the portion (e.g. 50%) that has been carried around secondary gear 24-1. Each high pressure side, 1B, 2B, 3B and 4B is therefore releasing respective port output total fluid (e.g. 100%) at fluid pressures higher than the inlet fluid pressures.
The total output of the system illustrated in 9 is therefore able to deliver the output flow equivalent of four pump pairs (i.e. 8 gears) using only 5 gears associated with 4 gear devices 23 in a common gear cavity 25, within the multi-cluster hydraulic gear device 20.
As can be seen, check valves, indicated generally at 30, and solenoids, indicated generally at 32, may be located within the fluid lines. Check valves may be located on the high pressure line, as seen in
Reference will now be made to
The following description of one use of the multi-cluster hydraulic gear device 20, described above, is provided as an example only and is not meant to be limiting to the application of the multi-cluster hydraulic gear device 20 described herein. For the purposes of this description, the use of the multi-cluster hydraulic gear device 20 will be described herein in reference to its use as a gear pump in a vehicle braking system. Examples of the types of vehicles that it may also be used in include, but are not limited to, rail applications over the road tractors, trailers, city buses, heavy duty commercial vehicles, light duty commercial and passenger vehicles.
The multi-cluster hydraulic gear device 20 includes an outer case 80 that is connected to a rotating towing or towed vehicle wheel. The device 20, used in a pump mode in this example, includes spur gears, or small gears, 94, which are fixed within a stationary housing 83 located inside the outer case 80. When braking is invoked, pilot fluid is injected into the clutch cylinder 82, which moves the clutch block 84 radially outward to engage with the rotating outer case. This action results in engagement of clutch plate 87 to the rotating outer case 80. Following this, clutch plate 87 starts to rotate mechanical drive gear 88, which is mechanically connected to clutch plate 87. This in turn spins all four mechanical spur gears 90, which are each connected to one of four small hydraulic spur gears, or secondary gears 94. The secondary gears 94 are as per the secondary gears 24 described above. Each of the secondary gears 94 in turn is connected to, and passively rotate, the ring gear, or main gear, 92. The main gear 92, is as per the main gear 22 described above. This initiates pumping action and fluid is drawn from a reservoir to the pump ports, not shown, at the meshing point. A partition wall 96 is positioned between the mechanical and hydraulic zones and is fitted with seals isolating the two compartments and the fluid.
Braking effort may be modulated by controlling (i) the displaced volume, i.e. how many pumps are activated; and (ii) the pressure head. When the fluid leaves the control valve, it may be sent to a filter for cleaning and a heat exchanger to dissipate kinetic brake energy before it is recirculated back to the pump. When the clutch is engaged to initiate fluid flow, all the secondary gears 94 begin to rotate, transferring fluid in direct proportion to their rotational speed and size. Total braking effort can then be modulated by a combination of two modes (i) step modulation and/or (ii) analog modulation.
In step modulation, opening of bypass solenoid(s) enables the individual pumps output by “shorting” fluid flow. In the case of the illustrated four pump cluster, seen in
The working pump A continuously pushes a portion (e.g. 50%) flow volume, of the fluid drawn in, to the bypassed pump B via drive gear 22, i.e. portion (e.g. 50%) is carried by drive gear 22 to pump B. An initial fluid is drawn into the low pressure side of Pump B, at position C, of this portion (e.g. 50%) is carried by the drive gear 22 to join with the portion (e.g. 50%) carried around pump A to result in total fluid output. Of the fluid drawn in at position C, portion (e.g. 50%) follows pump B around to meet with the portion (e.g. 50%) that has been passed from working pump A. The combined portions are then recirculated through the cluster. The net effect: the bypass solenoid has shorted out pump B and the circuit behaves as if that pump simply does not exist. Instead of outputting portion (e.g. 50%) of the fluid, the fluid is simply recirculated within pump B via the solenoid. In other words, the portion (e.g. 50%) volume has simply passed through as though pump B were not there. It will therefore be clear that every cluster that is in the bypass mode will always a fresh injection of portion (e.g. 50%) of cooled oil with every revolution. One advantage of the injection of fresh oil in the bypass mode is for cooling purposes of the overall device 20 and/or for respective gear devices 23 adjacent to the bypassed gear device 23.
Referring to
Therefore, in situations where higher hydraulic pressure with reduced fluid flow rates (e.g. fluid volume) is desired as total fluid output from the device 20, bypass valve(s) 9 are opened for one or more respective gear devices 23 so that the remaining working (e.g. pumping) gear device(s) 23 (those gear devices 23 not in bypass mode) can be used to provide the hydraulic higher pressure total fluid output. It is recognized that the terms higher and lower are relative to the gear device 20 working in non-bypass mode or otherwise having a greater number of gear devices 23 in non-bypass mode, as compared to the higher pressure and reduced volume provided by the remaining gear devices 23 that are hydraulically coupled to the total output of fluid from the gear device 20.
As noted, the gear device 20 can contain multiple gear devices 23 with respective by pass vales 9, such that selective bypass (via bypass valve 9 operation) of each gear device 23 within the gear device 20 can be implemented via operational control of the respective bypass valve 9 of the respective (i.e. associated with) gear device 23. It is also recognized that one bypass valve 9 can be associated with and therefore control the bypass mode with two of more gear devices 23, as desired. Another way to define bypass valve 9 operation is that bypass valve(s) 9 can be used to either engage hydraulically (via valve 9 close to block fluid flow there-through) or disengage hydraulically (via valve 9 open to allow fluid flow there-through) the respective associated gear device(s) 23 from the other gear device(s) 23 of the gear device 20.
Therefore, in effect the use of the bypass valve(s) 9 provides for hydraulic decoupling of the associated gear device(s) 23 from the total output flow of the device 20 while at the same time providing for the associated gear device(s) 23 to remain mechanically coupled in the gear cavity 25 with all of the other gear devices 23 contained therein. This is advantageous for gear cooling and lubrication purposes.
This can be repeated for more than one pump provided each includes a solenoid valve (e.g. bypass valve 9), or any other means that allows a pump gear cluster to be by-passed from the total number of gear devices/clusters 23 of the gear device 20, and allows for repeated flow of the fluid within pump B. Since pumps 23 are mechanically geared together, displacement can be identical and portion (e.g. 50%) of each input is passed to the nearest pump 23 output, limited pressure head can be generated and the serial handoff can occur at minimal pressure. Upon finally arriving at a “working pump” 23, the carried portion (e.g. 50%) joins the awaiting portion (e.g. 50%), and total combined portions exit (positive displacement device). Pressure output of the gear device 23 can be dictated by the control valve 8 setting. It will be understood that when the multi-cluster gear device 20 is engaged, if only one gear cluster device 23 is working, the by-pass loop allows for the rest of the gears to be kept lubricated and therefore cooled, i.e. whenever a situation arises where one or more pump gear cluster devices 23 is not working the gears do not run dry. In addition the gears are kept cool by continuous fluid flow.
In one embodiment, shown in
Referring to
Due to separation distances between shafts 100 for the secondary gears 102, in order to accommodate the main gear 106 positioned on shaft 104 between the two secondary gears 102, and potential unequal hydraulic pressures at the respective fluid ports 40, the gears 102 and/or the gear 106 can be forced away from one of their respective ports 40 and towards the other of their respective ports 40 due to a differential in port pressures, i.e. the respective gear(s) would be forced in a direction lateral to the longitudinal axis of their shaft 100,104 For example, where the multi-cluster hydraulic gear device 20 is used as a pump, then inlet port A would be at a lower pressure than outlet port B and thus secondary gear 102 there-between would be forced or otherwise biased by the fluid pressure differential of the ports A, B laterally away from port B and towards port A. In the present three gear example, the rotations of the gears is such that inlet port D would be at a lower pressure than outlet port C and thus secondary gear 102 there-between would also be forced or otherwise biased by the fluid pressure differential of the ports C, D laterally away from port C and towards port D. Thus it can be seen for some configurations of the multi-cluster hydraulic gear device 20, each port side of the gear cavity 25 includes both a high pressure port and a low pressure port. In other words, each port side of the gear cavity 25 includes both an inlet port and an outlet port.
A consequence of the lateral movement of the secondary gears 102 with respect to their longitudinal axis is that the separation clearance TOL is reduced (see
One mechanism to provide for acceptable material wear inside of the gear cavity 25 is to use a disposable (e.g. replaceable) sleeve 112, which is inserted via cavity face 115 of the gear cavity 25, between an inner surface 118 of the housing 42 body forming the gear cavity 25 and the distal ends 107 of the teeth 108 of the gears 102, 106. In this case the inner wall 118 located in the clearance zone 120 is positioned a combined distance of a thickness T of the sleeve 112 and the clearance TOL away from the nearest portion of the radial distal end surfaces 107 of the teeth 108, of the respective gear 102, 106. The inner surface 110 material of the sleeve 112 is selected so that if, and when, the distal ends 107 of the teeth 108 contact the inner surface 110, the material of the sleeve 112 is preferentially abraded over the material of the teeth 108. One advantage to using the sleeve 112 is that it can be replaced with excessive wear and can be a relatively low cost part compared to replacing damage or wear to the precision machined housing 42 itself (e.g. in the extreme case damage directly to the housing inner surface of the gear cavity 25 can require replacement of the entire machined housing 42). For example, the material of the sleeve 112 can be made of a material that is metallurgically softer than the material of the gear teeth themselves. Otherwise, the material of the gear teeth is of a different hardness (e.g. harder) than that of the material of the sleeve 112.
Sleeve 112 can be comprised of ductile material (e.g. iron) that will wear away preferably as a particulate (e.g. powder) rather than as shavings. In general, sleeve 112 preferably wears away as a powder rather than shavings, which can be destructive to the internal components (e.g. gears 102,106) of device 20. In some embodiments, sleeve 112 can be comprised of an oil-impregnated alloy, including copper or iron alloys, for example, that help reduce friction and wear between gears 102,106 and sleeve 112. Other examples of the sleeve 112 material can be sintered materials. These sintered materials are initially powder material held in a mold and then heated to a temperature below the melting point so that the atoms in powder particles diffuse across the boundaries of the particles, thus fusing the particles together and creating one solid piece as the sleeve 112. As noted, sleeve 112 has tight tolerances with gears 102 and gear 106 with respect to the inner surface 110. Tight tolerances using clearance TOL with sleeve 112 increases the efficiency of the gear device action of gear 102 and gear 106 to inhibit blow-by fluid loss between the gears 102,106 and interior surface 110 of housing 42, which would decrease the operational efficiency (e.g. pump efficiency) of the device 20. Sleeve 112 can include fluid apertures 41 that align with fluid ports 40 of the housing 42.
In terms of coupling of the sleeve 112 with the gear cavity 25, the sleeve 112 can be press fit (e.g. friction fit) into the gear cavity 25. Alternatively, or in addition to, the sleeve 112 can be fastened by a plurality of releasably secure fasteners 116 (see
In some embodiments, sleeve 112 can have a non-uniform thickness. For example, a portion (or portions) of sleeve 112 that is/are subject to increased wear may have increased thickness over that of adjacent portions, so that sleeve 112 can have a longer service time before requiring replacement due to wear.
A hydraulic system can also be used to measure wear of sacrificial sleeve 112. As sleeve 112 becomes more worn the efficiency of the device 20 action of gears 102,106 decreases of the gear devices 23. By measuring fluid flow relative to RPM of the drive shaft that is coupled to gears 102,106, the hydraulic system can measure the efficiency of device 20 and thus wear of sleeve 112. Hydraulic system can be coupled to a vehicle data bus to indicate a service requirement for the sleeve 112.
In some embodiments, sleeve 112 can be a partial sleeve 114 (or sleeves) that does/do not completely surround all of the distal radial surface ends 107 of the teeth 108 of gears 102,106, rather covers all or a portion of the interior surface 118 of the gear cavity 25 extending about the distal ends 107 of the teeth 108 in the clearance TOL zone 120 (see
In particular, the partial sleeve portion 114 can be positioned on the inner wall 118 of the gear cavity 25 and adjacent to the portion of the radial distal end surfaces 107 of the teeth 108 of the respective gear that are configured to have the predefined clearance TOL between the radial distal end surfaces 107 and the adjacent gear cavity 25 surface—e.g. surface 110 when sleeve 114 is used. In this case the inner wall 118 is positioned a combined distance of a thickness T of the inner sleeve portion 114 and the clearance TOL away from the nearest portion of the radial distal end surfaces 107 of the teeth 108, of the respective gear 102, 106. Alternatively, the partial sleeve portion 114 can be used only for a portion of a clearance TOL zone 120 to provide for sacrificial (e.g. predetermined, predefined, preferred) wear surface 110 while the remaining portion of the clearance TOL zone 120 can be provided by a non-sacrificial (e.g. non-predetermined, non-predefined, non-preferred) wear surface 118 of the housing 42 exposed in the gear cavity 25. An example of this configuration is shown in
Referring to
Referring to
Referring to
One example of the coupling mechanism 132 is a tongue 134 and groove 136 connection, such that the tongue 134 is slidably engaged with the groove or channel 136. It is recognised that the tongue 134 can be mounted on the slider block 130 and the groove is positioned in the mounting block 120. Alternatively, the tongue 134 can be mounted on the mounting block 120 and the groove is positioned in the slider block 120. The coupling mechanism 132 can be of a dovetail cross sectional shape, for example.
Referring to
However, as discussed above, due to potential unequal hydraulic pressures in the gear cavity 25 at the respective fluid ports 40, different portions of the thrust plates 134 can be forced away from or towards the nearest adjacent port 40 to the thrust plate 134 portion. A consequence of this biasing of different portions of the thrust plate 134 in respective different directions (e.g. either away from or towards) with respect to their respective adjacent port 40, is that the thrust plate 134 can become warped due to a differential in port 40 pressures. For example, as discussed for
Accordingly, one can understand that as this port pressure differences become more manifest due to increased operating pressures, the degree of warp and/or twist of thrust plate 134 can become more and more pronounced. The consequence of warp or twisting of the thrust plate 134 is that due to the tight tolerances of clearance TOL2, the degree of warping of the thrust plate 134 can become such that the clearance TOL2 is breached by the warping and therefore surface 142 opposing the sidewalls 140 of the gears 102,106 can come into contact therewith, thus causing undesirable wearing or abrading of the gear material and/or thrust plate material. The damage caused by this undesirable wear can result in undesirable increases in the clearance TOL2 (due to gear surface 140 wear and/or plate surface 142 wear) as well as damage to the gear teeth themselves due to wear material circulating in the gear cavity 25. This damage can be realaized/expressed as increase in blow-by of the fluid.
Referring again to
Referring to
Referring to
Referring to
Referring again to
Alternatively, the housing portions of thrust plate assembly 160 and housing portion 42-2 (see
While this invention has been described with reference to illustrative embodiments and examples, the description is not intended to be construed in a limiting sense. Thus, various modification of the illustrative embodiments, as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to this description. It is therefore contemplated that the appended claims will cover any such modifications or embodiments. Further, all of the claims are hereby incorporated by reference into the description of the preferred embodiments.
Any publications, patents and patent applications referred to herein are incorporated by reference in their entirety to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated by reference in its entirety.
Claims
1. A multi cluster gear device comprising:
- a shaft rotatable about a longitudinal axis;
- a primary gear mounted on the shaft;
- at least two secondary gears spaced about and positioned to engage with the primary gear;
- each of the at least two secondary gears configured to independently receive fluid from a fluid reservoir and to allow flow of a portion of the fluid about the secondary gear and to allow the remaining portion of the fluid to be carried by the primary gear to the adjacent secondary gear.
2. A multi cluster gear device comprising:
- a primary gear;
- at least two secondary gears spaced about and positioned to engage with the primary gear;
- each of the at least two secondary gears configured to independently receive fluid from a fluid reservoir and to allow flow of a portion of the fluid about the secondary gear and to allow the remaining portion of the fluid to be carried by the primary gear to the adjacent secondary gear.
3. The multi cluster gear device according to claim 2, wherein the at least two secondary gears are smaller than the primary gear.
4. The multi cluster gear device according to claim 2, wherein the at least two secondary gears are spaced evenly about the periphery of the primary gear.
5. The multi cluster gear device according to claim 2, wherein approximately 50% of the fluid received by each of the at least two secondary gears flows around respective secondary gears and the remaining fluid portion is carried to the adjacent secondary gear.
6. The multi cluster gear device according to claim 2, wherein the each of the secondary gears discharges approximately half of the total volume of fluid received, such that each of the secondary gears is associated with an input port and an output port, providing for a pair of ports per said each of the secondary gears.
7. The multi cluster gear device according to claim 6, wherein the gear device includes a third secondary gear engaged with the primary gear, the third secondary gear also having the pair of ports.
8. The multi cluster gear device according to claim 2, wherein each of the secondary gears is independently fluidly connected to a fluid inlet and a fluid outlet.
9. The multi cluster gear device according to claim 1, wherein the shaft is driven by a driving source and the multi cluster gear device is operable to function as a pump.
10. The multi cluster gear device according to claim 1, wherein the shaft is driven by the rotation of the primary and secondary gears.
11. The multi cluster gear device according to claim 2, wherein the at least two secondary gears are configured to receive fluid at low pressure.
12. The multi cluster gear device according to claim 1, wherein at least one of the at least two secondary gears are configured to receive fluid at high pressure.
13. The multi cluster gear device according to claim 1, comprising four secondary gears.
14. The multi cluster gear device according to claim 1, comprising three secondary gears.
15. The multi cluster gear device according to claim 1 further comprising a removable sleeve positioned in a gear cavity of a housing containing the primary and secondary gears, the sleeve positioned between an interior wall of the gear cavity and distal radial end surfaces of gear teeth of one or more of the primary gear and the secondary gears.
16. The multi cluster gear device according to claim 15, wherein the sleeve is provided as one or more sleeve segments.
17. The multi cluster gear device according to claim 16, wherein the sleeve segment is positioned around one of the secondary gears in a zone having a predefined blow-by gap clearance.
18. The multi cluster gear device according to claim 17, wherein the sleeve segment is positioned around a portion of the zone and the interior wall of the housing makes up the remaining portion of the zone.
19. The multi cluster gear device according to claim 15 further comprising a slider block of the sleeve to provide for movement of the sleeve in a direction lateral to a longitudinal axis of the secondary gear.
20. The multi cluster gear device according to claim 15 further comprising a slider block of the sleeve to provide for movement of the sleeve in a direction lateral to the longitudinal axis of the primary gear.
21. The multi cluster gear device according to claim 15, wherein the sleeve is comprised of a material that degrades as a powder.
22. The multi cluster gear device according to claim 21, wherein the material is a layer positioned on a main body of the sleeve.
23. The multi cluster gear device according to claim 1 further comprising a thrust plate positioned and floating between an end wall of a housing of the device and sidewalls of the primary gear and the secondary gears, and further comprising a thrust bearing positioned between the thrust plate and the sidewall of at least one of the primary gear and the secondary gears.
24. The multi cluster gear device according to claim 23, wherein the thrust plate is comprised of a material that degrades as a powder.
25. The multi cluster gear device according to claim 24, wherein the material is a layer positioned on a main body of the thrust plate.
26. The multi cluster gear device according to claim 2 further comprising a thrust plate positioned between an end wall of a housing of the device and the sidewalls of the primary gear and the secondary gears and further comprising a thrust bearing positioned between the thrust plate and the sidewall of at least one of the primary gear and the secondary gears.
27. The multi cluster gear device according to claim 26 further comprising a hardened surface on the sidewall adjacent to the thrust bearing.
28. The multi cluster gear device according to claim 1 further comprising a thrust plate positioned fixedly between an end wall of a housing of the device and sidewalls of the primary gear and the secondary gears.
29. The multi cluster gear device according to claim 28 further comprising one or more shoulders positioned with respect to the sidewalls of one or more of the primary gear and the secondary gears, the one or more shoulders for abutting a respective bearing portion mounted between the respective gear and the thrust plate.
30. The multi cluster gear device according to claim 29, wherein the shoulder is provided by a bushing that is positioned between the respective gear and the bearing portion.
31. The multi cluster gear device according to claim 29, wherein the shoulder is provided by a portion of the gear that contacts the bearing portion.
32. The multi cluster gear device according to claim 29, wherein the shoulder is provided by a shaft upon which the respective gear is mounted.
33. The multi cluster gear device according to claim 1 further comprising a thrust plate positioned between an end wall of a housing of the device and the sidewalls of the primary gear and the secondary gears, the end wall having a face with a first surface area exposed to pressurized hydraulic fluid such that the first surface area is greater than a second surface area of a face of the thrust plate also exposed to the pressurized hydraulic fluid, thus providing for a net inward force on the thrust plate towards the sidewalls.
34. The multi cluster gear device according to claim 28, wherein a gear cavity containing the primary and the secondary gears is positioned in the housing, the thrust plate and the gear cavity integral to the housing as a one piece construction.
35. A multi cluster gear device comprising:
- a shaft rotatable about a longitudinal axis;
- a primary gear mounted on the shaft;
- a pair of secondary gears spaced about and positioned to engage with the primary gear; wherein the primary gear and the secondary gears define a pair of gear devices for moving hydraulic fluid within a common gear cavity defined by a housing of the gear device.
36. The multi cluster gear device of claim 36 further comprising at least one additional secondary gear engaging with the primary gear to define another gear device in the common gear cavity, such that a number of ports providing communication of fluid into and out of the gear cavity is less than double the number of the gears within the common gear cavity.
37. A multi cluster gear device comprising:
- a primary gear;
- a pair of secondary gears spaced about and positioned to engage with the primary gear; wherein the primary gear and the secondary gears define a pair of gear devices for moving hydraulic fluid within a common gear cavity defined by a housing of the gear device.
Type: Application
Filed: Nov 26, 2012
Publication Date: Dec 12, 2013
Applicant: TONAND BRAKES INC. (London)
Inventor: Tonand Brakes Inc.
Application Number: 13/685,160