MULTIPLE PUMP UNIT AND VEHICLE WITH MULTIPLE PUMP UNIT
A multiple pump unit is used for operating a plurality of actuators, and includes a plurality of pump shafts and a plurality of hydraulic pumps. The plurality of pump shafts is driven by an electric motor. The plurality of hydraulic pumps is driven by the plurality of pump shafts. Pressurized oil for operating the plurality of actuators is fed out from the plurality of hydraulic pumps.
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This application claims the benefit of priority from prior Japanese Patent Application No. 2006-348759, filed in Japan on Dec. 26, 2006, the entire contents of which are incorporated herein by reference.
BACKGROUND1. Technical Field
The present invention generally relates to a multiple pump unit used for operating a plurality of actuators, and to a vehicle with such a multiple pump unit.
2. Related Art
Hydraulic pumps have been conventionally used for various purposes. For example, work vehicles such as a lawn mower vehicles, tractors, or trucks drive a hydraulic pump with an engine, and the hydraulic pressure produced is used to rotate two wheel-driving hydraulic motors, which are a plurality of actuators, which in turn drive the two front or rear wheels.
Further, a work vehicle such as a lawn mower vehicle or a tractor is sometimes used to drive working machines such as a mower or a cultivator, and to raise and lower the machine. As a result, the concept of creating a dual pump unit by combining two hydraulic pumps and driving the machine via a PTO (power take off) shaft capable of taking out power from the drive source was proposed.
For example, Japanese Patent Laid-Open Publication No. 2003-306052 discloses a pump unit including a PTO shaft and two hydraulic pump bodies. In the disclosed configuration, a first pump shaft and a second pump shaft are operationally connected to an input shaft connected to a drive source, and power transmission between the input shaft and the PTO shaft, and shutoff of the power transmission are made switchable by a hydraulic clutch mechanism provided between the input shaft and the PTO shaft. The first pump shaft drives a first hydraulic pump body, and pressurizes the oil supplied into the first hydraulic pump body from an oil supply port to discharge the oil from a discharge port. The second pump shaft drives a second hydraulic pump body, and pressurizes the oil supplied into the second hydraulic pump body from another oil supply port to discharge the oil from another discharge port.
A first hydraulic motor and a second hydraulic motor are respectively driven by the oil discharged from the first hydraulic pump body and the second hydraulic pump body, and wheels corresponding to them are rotated. Further, the PTO shaft and the working machine are connected by a transmission shaft.
In the case of the pump unit disclosed in Japanese Patent Laid-Open Publication No. 2003-306052, when the drive source is an engine, the engine must be driven whenever the wheels or an attachment are driven. Therefore, it still has room for improvement in the aspect of enhancement of quietness. For example, in the working vehicle including the pump unit disclosed in Japanese Patent Laid-Open Publication No. 2003-306052, when the drive source is an engine, the engine is always driven, and therefore use of the working vehicle in an environment where quietness is desired, such as an area near a residential district, is likely to be difficult due to the noise generated by the engine.
Further, although it has been conventionally conceived of driving one pump with one electric motor, with such a configuration the range of use is small, and usability is low. For example, when two wheels at both left and right sides are driven with one pump, independent control of the wheels is difficult, and it is likely to be difficult to make the turning radius small.
SUMMARYIt is an advantage of the present invention to provide a structure usable for many purposes and providing superior quietness, in a multiple pump unit and a vehicle with the multiple pump unit.
A multiple pump unit according to the present invention may be configured as a multiple pump unit used for operating a plurality of actuators, characterized by including a plurality of pump shafts driven by an electric motor, and a plurality of hydraulic pumps driven by the respective plurality of pump shafts, wherein pressurized oil for operating the plurality of actuators is fed out from the plurality of hydraulic pumps.
According to this constitution, a plurality of pump shafts which drive a plurality of hydraulic pumps are driven by the electric motor, and the pressurized oil for operating a plurality of actuators is fed out from the plurality of hydraulic pumps. Therefore, because electric power can be supplied to a secondary battery or the like from a generator or the like driven by an engine, and this electric power can then be supplied to the electric motor from the secondary battery or the like, the engine does not have to be always operated for operating the plurality of actuators. Therefore, the structure capable of providing very quiet operation is obtained. In addition, because the multiple pump unit can be used for a larger number of purposes, usability can be enhanced compared to configurations in which the electric motor drives only one pump shaft constituting a hydraulic pump.
Further, preferably, at least any one of the plurality of hydraulic pumps is a double port pump provided with a plurality of discharge ports in correspondence with one pump shaft, and the pressurized oil for operating the plurality of actuators is fed out from the plurality of discharge ports of the double port pump.
With this constitution, the pressurized oil for operating a larger number of actuators is fed out from the plurality of hydraulic pumps, and a larger number of actuators can be operated. Therefore, usability can be further enhanced.
Further, more preferably, a casing housing the plurality of hydraulic pumps and rotatably supporting a rotary shaft of the electric motor and the plurality of hydraulic pump shafts, and a PTO shaft rotatably supported by the casing are included, the rotary shaft of the electric motor and the plurality of hydraulic pump shafts are operationally connected, and power transmission is made selectively possible between the rotary shaft of the electric motor and the PTO shaft by a clutch mechanism.
According to this constitution, irrespective of the rotation of the electric motor, operation and non-operation of the working machine or the like operationally connected to the PTO shaft can be selected by the clutch mechanism, and usability can be further enhanced.
Further, more preferably, a PTO shaft side pulley fixed to the PTO shaft projecting from the casing is included.
Further, more preferably, a cooling fan is fixed to at least one of a rotary shaft of the electric motor or a hydraulic pump shaft among the plurality of hydraulic pumps
With this constitution, the equipment including the electric motor and the plurality of hydraulic pumps can be easily cooled, making it easier to further enhance performance.
Further, more preferably, a casing housing the plurality of hydraulic pumps, and a cooling air guide part fixed to an outer side of the casing and guiding cooling air generated by the cooling fan along the outer side of the casing are included.
With this constitution, the casing can be easily cooled by the cooling air, making it still easier to further enhance performance.
Further, a vehicle with a multiple pump unit according to the present invention includes the above described multiple pump unit, a secondary battery or a fuel cell supplying electric power to the electric motor, and electric power supply state selecting unit selecting whether to supply electric power to the electric motor from the secondary battery or the fuel cell, or to shut off the supply of the electric power to the electric motor from the secondary battery or the fuel cell.
Further, more preferably, a working machine supported by a vehicle body, and a working machine side pulley operationally connected to the working machine are included, the multiple pump unit includes a casing housing the plurality of hydraulic pumps, and rotatably supporting a rotary shaft of the electric motor and the plurality of hydraulic pump shafts, and a PTO shaft rotatably supported by the casing, the rotary shaft of the electric motor and the plurality of hydraulic pump shafts are operationally connected, power transmission is made selectively possible between the rotary shaft of the electric motor and the PTO shaft by a clutch mechanism, a PTO shaft side pulley fixed to the PTO shaft projected from the casing is included, and a belt is provided between the PTO shaft side pulley and the working machine side pulley.
Further, more preferably, the plurality of actuators driven by the pressurized oil from the multiple pump unit are two wheel-driving hydraulic motors.
Further, more preferably, a generator driven by an engine is included, and electric power generated by the generator is supplied to the electric motor via the secondary battery or directly.
Further, more preferably, an engine side pulley capable of being selectively connected to an output shaft of an engine by a clutch, and a working machine supported by a vehicle body, and a working machine side pulley operationally connected to the working machine are included, and a belt is provided between the engine side pulley and the working machine side pulley.
Further, more preferably, a plurality of actuators driven by the pressurized oil from the multiple pump unit are each any of a working machine raising and lowering cylinder device raising and lowering a working machine, a working machine drive device driving the working machine, and a working machine tilting cylinder device tilting to displace the working machine, and electric power is supplied to a wheel-driving electric motor from any of the secondary battery, the fuel cell, and a generator to drive the wheel-driving electric motor.
Further, more preferably, a charge pump provided to replenish at least any one of the plurality of hydraulic pumps with pressurized oil is included.
Hereinafter, embodiments of the present invention will be described in detail while referring to the drawings.
First, based on
The dual pump unit 16 is used for operating the two wheel-driving hydraulic motors 18 and 20 via a hydraulic circuit, and includes an electric motor 26, and a dual pump (DUP) 28 having two hydraulic pumps. The electric motor 26 is supplied with electric power from the battery 14 and drives two pump shafts constituting the dual pump 28. Because the two hydraulic pumps are driven by the two pump shafts, pressurized oil is discharged from the two hydraulic pumps and the discharged pressurized oil operates the two wheel-driving hydraulic motors 18 and 20 provided at the left and right of the vehicle via the hydraulic circuit. Specifically, the hydraulic motors 18 and 20 are driven.
Further, the power of the electric motor 26 is transmitted to the PTO shaft from the dual pump unit 16, then transmitted to a pulley fixed to a driven shaft for driving the working machine 24 via a pulley fixed to the PTO shaft and a belt, and the working machine 24 is thus driven.
Further, the controller 22 sends a control signal to a DC/DC converter, not shown, connected to the battery 14, and controls the electric power taken out from the battery 14. Further, the controller 22 sends a control signal to an inverter not shown connected to the electric motor 26, and controls the output of the electric motor 26.
Next, based on
The working vehicle 30 includes a frame 42 constituting a vehicle body, the engine 10 which is an on-vehicle internal combustion engine supported by the frame 42, the generator 12 which is operationally connected to an output shaft of the engine 10 (specifically, has its drive shaft operationally connected to the output shaft), the battery 14 (see
The two wheels 32 which are rear wheels are supported at an intermediate portion in the longitudinal direction of the frame 42, and a pair of left and right casters 43 are supported at portions separated to the left and the right at a front end portion of the frame 42. The mower 38 is provided between the caster 43 and the wheels 32 with respect to the longitudinal direction of the frame 42. The mower 38 is supported at the frame 42 to be adjustable in the height direction. Further, the mower 38 is provided with a discharge duct 47 for discharging cut grass rearward. The discharge duct 47 extends rearward through a space between the first hydraulic motor 34 and the second hydraulic motor 36 provided to correspond to the two wheels 32.
The dual pump unit 16 includes a casing 44, the electric motor 26 (
Pair of operation levers 40 are provided to the left and right of the driver's seat, and are used to adjust the hydraulic pressure which is supplied to each of the hydraulic motors 34 and 36 and adjust the drive force of the two left and right wheels 32 independently at the left and the right. In the example shown in the drawings, only the rear wheels of the working vehicle 30 are driven, but a hydraulic motor may be provided to correspond to each of four wheels in total, that is, two wheels for each of both left and right sides so that the two hydraulic motors of one of the left and right sides are driven by the pressurized oil discharged from one hydraulic pump, and the two hydraulic motors corresponding to the two wheels at the other one of the left and right sides are driven by the pressurized oil discharged from the other hydraulic pump.
Further, the dual pump unit 16 is capable of transmitting the power of the electric motor 26 to the PTO shaft 45 via a gear mechanism and a hydraulic clutch mechanism which will be described later. A lower end portion of the PTO shaft 45 is projected downward from a lower side of the casing 44, and a PTO shaft side pulley 48 is fixed to it. A belt 52 is provided between the PTO shaft side pulley 48 and a working machine side pulley 50 fixed to the driven shaft of the mower 38. Specifically, the working machine side pulley 50 is operationally connected to the mower 38. By such a constitution, the mower 38 is made drivable by the power of the electric motor 26.
In the dual pump unit 16, the first pump shaft and the second pump shaft, which will be described later, are operationally connected to the output shaft of the electric motor 26. Specifically, the output shaft of the electric motor 26 and the first pump shaft are constituted of a common drive shaft 58, and the output shaft of the electric motor 26 and a second pump shaft 60 are connected to be capable of transmitting power by a gear mechanism 62. As shown in
Returning again to
The charge pump 68 has the function of replenishing an oil deficit caused as a result of oil leakage which is caused by the oil circulating in the hydraulic circuit and the like. More specifically, the charge pump 68 sucks oil from an external tank 72 through a filter 70, pressurizes the oil, supplies the oil to a hydraulic path at a low pressure side through a check valve 74, and supplies part of the oil to a hydraulic path at a high pressure side through another check valve 74 as necessary. Specifically, a discharge side of the charge pump 68 branches into a charge line 220 and a working oil line 222 from a main pressurized oil line 216 via a pressure reducing valve 218 for setting charge pressure. A relief valve 76 has a function of maintaining the hydraulic pressure of the main pressurized oil line 216. The external tank 72 is connected to the casing 44 which is a pump case, so that oil is supplied to the tank 72 from an oil reservoir in the casing 44. The first hydraulic pump 54 and the second hydraulic pump 56 are housed in the casing 44.
The pressurized oil discharged from the first hydraulic pump 54 is supplied to the first hydraulic motor 34 corresponding to the wheel 32 at one side (upper side in
Further, the pressurized oil discharged from the second hydraulic pump 56 is supplied to the second hydraulic motor 36 corresponding to the wheel 32 at the other side (lower side of
The charge line 220 and the hydraulic circuit including the second hydraulic pump 56 are connected by a connecting line 80. The oil supplied from the connecting line 80 is supplied to a low pressure side of the hydraulic path including the second hydraulic pump 56 through a check valve 82, and part of it is supplied to a high pressure side of the hydraulic path including the second hydraulic pump 56 through another check valve 82. Oil reservoirs in the casing respectively constituting the first hydraulic motor 34 and the second hydraulic motor 36 are connected to the tank 72.
Further, bypass valves 84 are provided at bypass paths disposed in parallel with respect to the flow of the pressurized oil for the respective hydraulic pumps 54 and 56, and, by opening the bypass valves 84, the supply of the pressurized oil to the hydraulic motors 34 and 36 corresponding to the opened bypass valves 84 from the respective hydraulic pumps 54 and 56 is stopped. Thereby, the load on the hydraulic motors 34 and 36 can be removed when, for example, it is desired to push or otherwise forcibly move the working vehicle 30 when the electric motor is stopped. Such bypass valves 84 can be made manually operated valves.
Further, the second pump shaft 60 and a drive side member 86 are operationally connected by a gear mechanism 88, and a hydraulic clutch mechanism 90 is provided between the drive side member 86 and the PTO shaft 45. Thus, power transmission between the drive side member 86 and the PTO shaft 45 is selectively made possible by the hydraulic clutch mechanism 90. The pressurized oil from the main pressurized oil line 216 is allowed to be supplied to the hydraulic clutch mechanism 90 by the working oil line 222. Though not illustrated, a hydraulic path may be branched from the charge line 220 or the main pressurized oil line 216, and by the pressurized oil from the branched hydraulic path, the actuator, such as a cylinder for raising and lowering the mower 38 (see
Next, a specific example structure of the dual pump unit 16 which is the multiple pump unit of this embodiment will be described in more detail by referring to
As a gear part fixed to the output shaft 64 of the electric motor 26 is disposed between the first pump shaft 66 and the second pump shaft 60, the first pump shaft 66 and the second pump shaft 60 and the output shaft 64 of the electric motor 26 are operationally connected by the gear mechanism 62. The output shaft 64 of the electric motor 26 is extended to the side opposite from the first pump shaft 66 and the second pump shaft 60. A cooling fan 96 is fixed to a portion that is one end portion (upper end portion in
The first hydraulic pump 54 and the second hydraulic pump 56 are both variable displacement axial piston pumps, and each includes a plurality of piston cylinder mechanisms 98 disposed around the first pump shaft 66 (or the second pump shaft 60), and a movable swash plate mechanism 100 which restricts a stroke length of each of the pistons when a plurality of piston cylinder mechanisms 98 rotate around the first pump shaft 66 (or the second pump shaft 60). The movable swash plate mechanism 100 controls the degree and direction of the inclination with respect to the first pump shaft 66 (or the second pump shaft 60) by a swash plate control shaft, whereby the amount of oil sucked and discharged by the piston cylinder mechanism 98 is controlled. By reversing the direction of the swash plate, the pressure increasing side and the pressure decreasing side are switched with one another. The pressurized oil discharged from the first hydraulic pump 54 and the second hydraulic pump 56 as above is supplied to the first hydraulic motor 34 and the second hydraulic motor 36 (
As shown in
Meanwhile, the drive side member 86 is supported on an outside diameter side of an intermediate portion of the PTO shaft 45 in such a manner that the components are rotatable relative to each other, and the hydraulic clutch mechanism 90 is provided between the drive side member 86 and the PTO shaft 45. The hydraulic clutch mechanism 90 includes a plurality of drive side friction plates which are supported around a lower side portion of the drive side member 86 to be incapable of relative rotation and capable of displacement in an axial direction, and includes a plurality of driven side friction plates which are supported at a driven side member 104 fixed to a circumference of the PTO shaft 45 to be incapable of relative rotation and capable of displacement in the axial direction, and applies a resilient force to a member which brings the drive side friction plates and the driven side friction plates in pressure contact with each other in a direction to be away from each other by biasing means 106. Further, the hydraulic clutch mechanism 90 includes a clutch pressing moving member 108 which receives the action of hydraulic pressure and presses the either one of the friction plates so that the drive side friction plates and the driven side friction plates are engaged with each other. A gear constituting the gear mechanism 88 is integrally provided at an upper portion of the drive side member 86. The power of the second pump shaft 60 is transmitted to the drive side member 86 by the gear mechanism 88.
In such a hydraulic clutch mechanism 90, in the state in which the drive side friction plates and the driven side friction plates are engaged by movement of the clutch pressing moving member 108, power transmission to the PTO shaft 45 from the output shaft 64 of the electric motor 26 is made possible, and, in a state in which engagement of the drive side friction plates and the driven side friction plates is released, power transmission to the PTO shaft 45 from the output shaft 64 of the electric motor 26 is shut off. When the PTO shaft 45 is driven, whereby the power of the PTO shaft 45 is transmitted to the driven shaft of the mower 38 via the PTO shaft side pulley 48, the belt 52, and the working machine side pulley 50 (
In the example multiple pump unit vehicle with the multiple pump unit of the present embodiment as above, the first pump shaft 66 (
In addition, the multiple pump unit can be used for a greater number of applications and usability can be enhanced compared to configurations in which the electric motor 26 drives only one pump shaft constituting the hydraulic pump. In the case of this embodiment, the different hydraulic motors 34 and 36 corresponding to the two wheels 32 can be driven by the pressurized oil from the different hydraulic pumps 54 and 56, and the two hydraulic motors 34 and 36 can be more effectively controlled independently. As a result, by making the output of one of the two hydraulic motors 34 and 36 larger than the output of the other hydraulic motor, the working vehicle 30 can be smoothly turned while skidding of the wheels 32 is suppressed. On the other hand, when the two hydraulic motors 34 and 36 corresponding to the two left and right wheels 32 are driven by the pressurized oil from one hydraulic pump, a flow dividing valve for directing the oil into the two hydraulic motors 34 and 36 must be provided in the hydraulic circuit, and it has room for improvement from the aspect of enhancement of usability.
Further, the casing 44 which houses the first hydraulic pump 54 and the second hydraulic pump 56, and rotatably supports the output shaft 64 of the electric motor 26, the first pump shaft 66 (
Because the cooling fan 96 (
Next,
Further, the belt 52 is provided between the engine side pulley 112 and the working machine side pulley 50 fixed to the driven shaft of the mower 38. Specifically, the working machine side pulley 50 is operationally connected to the mower 38. Thereby, in the state in which the clutch mechanism 110 is connected, the mower 38 is drivable by the power of the engine 10. The constitution shown in
Next,
Meanwhile, the dual pump unit 16a is not provided with the PTO shaft 45, the hydraulic clutch mechanism 90, the drive side member 86, or the gear mechanism 88 (see
The constitution and operation are otherwise the same as in the first embodiment shown in
In the embodiments described above, with respect to the second embodiment shown in
As the constitution and operation are otherwise the same as in the second embodiment shown in
The constitution and operation of the present embodiment are otherwise the same as in the second embodiment shown in
As the constitution and operation are otherwise the same as in the second embodiment shown in
In order to fix the outer cover 116 to the outer side of the casing 44 by screw, in the case of the example shown in the drawing, projection portions 122 projecting toward an outer side with respect to the diameter direction of the drive shaft 114 are formed at a plurality of spots of the outer surface of the casing 44, and bolts penetrating through the outer cover 116 are connected to the projection portions 122. The dual pump unit 16e can be disposed so that the drive shaft 114 is parallel with the longitudinal direction with the cooling fan 96 side (upper side in
Further, a small hole 124, a first long hole 126, and a second long hole 128 are formed in the outer cover 116 in sequence from the end portion at the charge pump 68 side toward the end portion at the cooling fan 96 side. A supply pipe 130 for supplying oil to the charge pump 68 is connected to the charge pump body 102, and the supply pipe 130 is led outside the outer cover 116 through the small hole 124. Two supply and discharge pipes 132 for supplying and discharging oil to and from each of the first hydraulic pump 54 and the second hydraulic pump 56, four supply and discharge pipes 132 in total, are connected to the casing 44, and the four supply and discharge pipes 132 are led outside the outer cover 116 through the first long hole 128. Further, an end portion of a connecting pipe 134 for connecting the inside of the casing 44 and the external tank 72 (see
According to the embodiment as above, the casing 44 which houses the first hydraulic pump 54, the second hydraulic pump 56, and a portion of the electric motor 26, and the outer cover 116 which is fixed to the outer side of the casing 44 to guide the cooling air caused by the cooling fan 96 along the outer side of the casing 44 are included. Therefore, the casing 44 can be easily cooled by the cooling air, and performance of the first hydraulic pump 54, the second hydraulic pump 56, and the electric motor 26 inside the casing 44 can be further and simply enhanced.
As the constitution and operation are otherwise the same as those in the third embodiment shown in
In the first embodiment shown in
Further, as shown in
Next,
Further, the electric power from the battery 14 (see
As the constitution and operation are otherwise the same as in the first embodiment shown in
As the constitution and operation are otherwise the same as those in the first embodiment shown in
The constitution and operation are otherwise the same as in the first embodiment shown in
Further, a braking device 170 is provided at the other end portion (left end portion in
As the constitution and operation are otherwise the same as in the first embodiment shown in
The braking structure provided in the wheel support structure is not limited to the structure as in this embodiment, but, for example, a disc brake and an electromagnetic brake can be adopted.
In this embodiment, instead of the first hydraulic motor 34 and the second hydraulic motor 36 (see
Further, the ring gear 160 constituting the planetary gear mechanism 178a of the first stage and the second ring gear 190 constituting the planetary gear mechanism 178b of the second stage are fixed to the housing 166 inside the wheel support member 164. For this purpose, a plurality of pins 192 are inserted through the holes formed in part of the housing 166, and one end portions (lower end portions in
As the constitution and operation are otherwise the same as those in the tenth embodiment shown in
The constitution and operation are otherwise the same as in the tenth embodiment shown in
Further, a bearing 200 is provided between one end portion (right end portion in
The constitution and operation are otherwise the same as in the tenth embodiment shown in
Further, the electric power from the battery 14 can be supplied to the first electric motor 148 and the second electric motor 150, which are wheel-driving electric motors for driving the two wheels 32. The electric power drawn from the battery 14 is controlled by the controller 22. The first electric motor 148 and the second electric motor 150 drive the wheels 32 via the planetary gear mechanisms 78. The electric motor 26 can drive a first pump shaft of a first hydraulic pump 54a and the second pump shaft constituting the second hydraulic pump 56, which constitute the dual pump unit 16f. The basic constitution for driving the first pump shaft and the second pump shaft is the same as that of the dual pump unit 16a of the second embodiment shown in
Especially in the dual pump unit 16f of this embodiment, as a discharge port of the first hydraulic pump 54a, two kidney-shaped (reniform) or arc-shaped discharge holes are formed at an outer side and an inner side with respect to the diameter direction in the portion existing around the first pump shaft. Thus, the first hydraulic pump 54a is formed as a double port pump provided with two discharge ports corresponding to the one first pump shaft. Through the driving of the first pump shaft, the pressurized oil is simultaneously fed out from the two discharge ports of the first hydraulic pump.
Oil is fed to the first hydraulic pump 54a and the second hydraulic pump 56 from the external tank 72 via the filter 70 and then pressurized, so that the pressurized oil is supplied to a pair of the extending and contracting hydraulic cylinder devices 204a and 204b and the raising and lowering hydraulic cylinder device 206. Specifically, the pressurized oil discharged from one discharge port out of the two discharge ports of the first hydraulic pump 54a is capable of being selectively supplied to two chambers of an extending and contracting hydraulic cylinder 210a by a switching valve 208a constituting the one extending and contracting hydraulic cylinder device 204a of the pair of extending and contracting hydraulic cylinder devices 204a and 204b. The pressurized oil discharged from the other discharge port out of the two discharge ports of the first hydraulic pump 54a is capable of being selectively supplied to two chambers of a raising and lowering hydraulic cylinder 214 by a switching valve 212 constituting the raising and lowering hydraulic cylinder device 206.
On the other hand, the pressurized oil discharged from the discharge port of the second hydraulic pump 56 is capable of being selectively supplied to two chambers of an extending and contracting hydraulic cylinder 210b by a switching valve 208b constituting the other extending and contracting hydraulic cylinder device 204b of the pair of extending and contracting hydraulic cylinder devices 204a and 204b. Further, in the neutral positions of the switching valves 208a, 212 and 208b, the pressurized oil from the first hydraulic pump 54a or the second hydraulic pump 56 is returned to the casing 44. The oil reservoir in the casing 44 is caused to communicate with the tank 72.
According to such a working vehicle, as in each of the above described embodiments, quieter performance can be achieved because it is not necessary that the engine 10 be continually operated in order to raise and lower the cultivator or displace the tilt of the cultivator. Further, with the constitution in which the first hydraulic pump 54a is made a double port pump provided with the two discharge ports corresponding to the first pump shaft, and the pressurized oil for operating the extending and contracting hydraulic cylinder device 204a and the raising and lowering hydraulic cylinder device 206 which are the two actuators is fed out from the two discharge ports of the first hydraulic pump 54a, the pressurized oil for actuating a larger number of actuators is fed out from the first hydraulic pump 54a and the second hydraulic pump 56, and can operate a larger number of actuators. Therefore, operability can be further enhanced.
Although in this example the cultivator is driven by a working machine driving electric motor (not illustrated) supplied with electric power from the engine 10 or the battery 14, the cultivator can be also driven by a hydraulic motor supplied with the pressurized oil from the first hydraulic pump 54a or the second hydraulic pump 56. Specifically, in
The dual pump unit 16f of this embodiment shown in
The pressurized oil discharged from the first hydraulic pump 54 is supplied to a first hydraulic motor 34a corresponding to the wheel 32 on one side of the wheels 32 on the left and right (upper side in
Especially in this embodiment, the first hydraulic motor 34a and the second hydraulic motor 36a are both variable displacement hydraulic motors. For example, each of the hydraulic motors 34a and 36a may be a swash plate type variable displacement piston motor. For example, a plurality of piston cylinder mechanisms disposed around the motor rotary shaft of each of the hydraulic motors 34a and 36a, and a movable swash plate mechanism which restricts a stroke length of each piston when a plurality of piston cylinder mechanisms rotate around the motor rotary shaft are included. The movable swash plate mechanism controls the degree of inclination with respect to the motor rotary shaft by a swash plate control shaft. Specifically, a tilt angle of the swash plate is made adjustable. The tilt angle of the swash plate of each of the hydraulic motors 34a and 36a changes in two stages of predetermined large displacement and small displacement or continuously within a range from a predetermined large displacement to a predetermined small displacement, in correspondence with a control signal from the controller 22 (see
In the case of a working vehicle using such variable displacement hydraulic motors 34a and 36a, the wide range of the deceleration ratio makes it possible to more easily respond to increases in speed of the working vehicle than possible with the working vehicle using a fixed displacement hydraulic motor.
As the constitution and operation are otherwise the same as those in the first embodiment shown in
In contrast to each of the above-described embodiments of the present invention, in this reference example, no second hydraulic pump 56 (see
The pressurized oil discharged from the first hydraulic pump 54 is supplied to an axle rotating hydraulic motor 224. A pinion shaft 228 constituting an input part of a differential gear device 226 is rotationally driven by a rotary shaft (not shown) constituting the axle rotating hydraulic motor 224. Further, side gears (not shown) at both left and right sides constituting the differential gear device 226 are rotated by the rotation of the pinion shaft 228. The side gears are fixed to an axle 230 connected to the left and right wheels 32. Therefore, by the rotational drive of the axle rotating hydraulic motor 224, the left and right wheels 32 are rotated. By reversing the tilting direction of the swash plate of the first hydraulic pump 54, that is, the direction in which the swash plate inclines with rotation, the hydraulic motor 224 is made rotatable in any normal or reverse direction.
Further, the axle rotating hydraulic motor 224 is provided with a bypass valve 84 in a bypass route disposed in parallel with respect to the flow of the pressurized oil, so that, when the bypass valve 84 is opened, shortcut is taken between the discharge side and the suction side of the axle rotating hydraulic motor 224. Thereby, when it is desired that the working vehicle 30 be forcibly moved, for example, in a state in which the electric motor is stopped and the like, the load on the axle rotating hydraulic motor 224 can be removed.
Free wheel preventing lines 234 for drawing pressurized oil from the reservoir inside the casing 44a are respectively connected at a discharge side and a suction side at the time of normal rotation of the first hydraulic pump 54 of a main pressurized oil line 232 connecting the first hydraulic pump 54 and the axle rotating hydraulic motor 224. Second check valves 236 are provided at the respective free wheel preventing lines 234. The second check valve 236 has the function of replenishing pressurized oil to the main pressurized oil line 232 from the reservoir to prevent the working vehicle from slipping down due to shortage of the pressurized oil of part of the main pressurized oil line 232 when the working vehicle stops on an uphill or a downhill.
The main pressurized oil line 232, the charge line 220, the axle rotating hydraulic motor 224, the bypass valve 84, the differential gear device 226 and a portion including part of the axle 230 are housed in the casing 44a housing the electric motor 26 and the first hydraulic pump 54, and the casing 44a and the elements housed in the casing 44a are set as a single unit.
In the reference example as above, as in each of the above-described embodiments, when electric power is supplied to the battery 14 (see
As the constitution and operation are otherwise the same as those in the above-described first embodiment, redundant explanation will be omitted by assigning the same reference numerals and characters to the equivalent parts and not repeating their explanation here.
SECOND REFERENCE EXAMPLE RELATING TO THE PRESENT INVENTIONFurther, the charge pump 68 is disposed between the first hydraulic pump 54 and the electric motor 26, so that the first hydraulic pump 54, the electric motor 26 and the charge pump 68 may be rotationally driven at the same time by the drive shaft 114. Unlike this reference example, the first hydraulic pump 54, the electric motor 26 and the charge pump 68 are disposed to be in the same positional relationship as in the first reference example shown in
In the case of this reference example as above, in the working vehicle, the degree of freedom of disposition of the parts can be enhanced to a greater degree than in the first reference example shown in
As the constitution and operation are otherwise the same as in the first reference example shown in
In this embodiment, the electric motor 26, the first hydraulic pump 54, the first hydraulic motor 34 and the planetary gear mechanism 78 corresponding to the first hydraulic motor 34 are housed in a first casing 244, and the second hydraulic pump 56, the second hydraulic motor 36 and the planetary gear mechanism 78 corresponding to the second hydraulic motor 36 are housed in a second casing 246. Further, a charge pump 68a is driven by the second pump shaft 60. The charge pump 68a is housed in the second casing 246, pressurizes the oil sucked from the oil reservoir in the second casing 246, and supplies the oil to a hydraulic path at a low pressure side via the check valve 82.
The cooling fan 96 and a drive side pulley 248 are fixed to the drive shaft 114 projected outside the first casing 244. The cooling fan 96 and a driven side pulley 250 are fixed to the second pump shaft 60 projected outside the second casing 246. A belt 252 is looped over the drive side pulley 248 and the driven side pulley 250. Therefore, when the drive shaft 114 rotates, the second pump shaft 60 also rotates via the belt 252. Specifically, the drive shaft 114 and the second pump shaft 60 are operationally connected.
Suction sides of the charge pump 68 which is driven by the drive shaft 114 and the charge pump 68a which is driven by the second pump shaft 60 are respectively connected to the oil reservoirs inside the first casing 244 and the second casing 246. Further, a manual switching valve 254 is provided in a bypass path disposed in parallel with respect to the flow of the pressurized oil for each of the hydraulic pumps 54 and 56. By switching the manual switching valve 254, it is possible to select whether to continue the bypass path at a region of the manual switching valve 254, or to cause the suction side and the discharge side of the hydraulic pump 54 (or 56) to communicate with the oil reservoir inside the first casing 244 or the second casing 246. In the present example, as in the first embodiment shown in
As the constitution and operation are otherwise the same as in the first embodiment described above, redundant explanation will be avoided by assigning the same reference numerals and characters to the equivalent parts and not repeating their description here.
THIRD REFERENCE EXAMPLE RELATING TO THE PRESENT INVENTIONAs the constitution and operation are otherwise the same as in the sixteenth embodiment shown in
Further, in each of the above described embodiments, electric power can be directly supplied to the electric motor 26 from the generator 12 or the fuel cell instead of supplying the electric power generated in the generator 12 or the fuel cell to the secondary battery such as the battery 14 and supplying the electric power to the electric motor 26 from the secondary battery. In such a case, power supply switching unit may be provided at either the generator 12 or the fuel cell, or between the secondary battery and the electric motor 26, and by the power supply switching unit, supply of the electric power to the electric motor 26 directly from the generator 12 or the fuel cell, or supply of the electric power to the electric motor 26 from the secondary battery can be made switchable automatically or manually by an operation part such as a switch. For example, when the charge amount of the secondary battery is at a predetermined value or less, electric power can be automatically supplied to the electric motor 26 directly from the generator 12 or the fuel cell.
Of the above-described respective embodiments, in the case of driving the working machine except for the wheels 32 which are the drive wheels by hydraulic pressure from the hydraulic pump in the fourteenth embodiment shown in
Claims
1. A multiple pump unit used for operating a plurality of actuators, comprising:
- a plurality of pump shafts driven by an electric motor; and
- a plurality of hydraulic pumps driven by the respective plurality of pump shafts,
- wherein pressurized oil for operating the plurality of actuators is fed out from the plurality of hydraulic pumps.
2. The multiple pump unit according to claim 1,
- wherein at least any one of the plurality of hydraulic pumps is a double port pump provided with a plurality of discharge ports in correspondence with one pump shaft, and
- the pressurized oil for operating the plurality of actuators is fed out from the plurality of discharge ports of the double port pump.
3. The multiple pump unit according to claim 1, further comprising:
- a casing housing the plurality of hydraulic pumps, and rotatably supporting a rotary shaft of the electric motor and the plurality of hydraulic pump shafts; and
- a PTO shaft rotatably supported by the casing,
- wherein the rotary shaft of the electric motor and the plurality of hydraulic pump shafts are operationally connected, and
- power transmission is made selectively possible between the rotary shaft of the electric motor and the PTO shaft by a clutch mechanism.
4. The multiple pump unit according to claim 3, further comprising:
- a PTO shaft side pulley fixed to the PTO shaft projecting from the casing.
5. The multiple pump unit according to claim 1,
- wherein a cooling fan is fixed to at least one of a rotary shaft of the electric motor or a hydraulic pump shaft among the plurality of hydraulic pumps.
6. The multiple pump unit according to claim 5, further comprising:
- a casing housing the plurality of hydraulic pumps; and
- a cooling air guide part fixed to an outer side of the casing and guiding cooling air generated by the cooling fan along the outer side of the casing.
7. A vehicle with a multiple pump unit, comprising:
- the multiple pump unit according to claim 1;
- a secondary battery or a fuel cell supplying electric power to the electric motor; and
- electric power supply state selecting unit selecting whether to supply electric power to the electric motor from the secondary battery or the fuel cell, or to shut off the supply of the electric power to the electric motor from the secondary battery or the fuel cell.
8. The vehicle with the multiple pump unit according to claim 7, comprising:
- a working machine supported by a vehicle body; and
- a working machine side pulley operationally connected to the working machine,
- wherein the multiple pump unit is the multiple pump unit according to claim 4, and a belt is provided between the PTO shaft side pulley and the working machine side pulley.
9. The vehicle with the multiple pump unit according to claim 7,
- wherein the plurality of actuators driven by the pressurized oil from the multiple pump unit are two wheel-driving hydraulic motors.
10. The vehicle with the multiple pump unit according to claim 7, further comprising:
- a generator driven by an engine,
- wherein electric power generated by the generator is supplied to the electric motor via the secondary battery or directly.
11. The vehicle with the multiple pump unit according to claim 7, further comprising:
- an engine side pulley capable of being selectively connected to an output shaft of an engine by a clutch;
- a working machine supported by a vehicle body; and
- a working machine side pulley operationally connected to the working machine,
- wherein a belt is provided between the engine side pulley and the working machine side pulley.
12. The vehicle with the multiple pump unit according to claim 7,
- wherein a plurality of actuators driven by the pressurized oil from the multiple pump unit are each any of a working machine raising and lowering cylinder device raising and lowering a working machine, a working machine drive device driving the working machine, and a working machine tilting cylinder device tilting to displace the working machine, and
- electric power is supplied to a wheel-driving electric motor from any of the secondary battery, the fuel cell and a generator to drive the wheel-driving electric motor.
13. The vehicle with the multiple pump unit according to claim 7, further comprising:
- a charge pump provided to replenish at least any one of the plurality of hydraulic pumps with pressurized oil.
Type: Application
Filed: Dec 20, 2007
Publication Date: Jun 26, 2008
Applicant: KANZAKI KOKYUKOKI MFG. CO., LTD. (Hyogo)
Inventors: Norihiro ISHII (Hyogo), Yoshitaka ISHIMARU (Hyogo)
Application Number: 11/961,248
International Classification: F04B 17/03 (20060101);