JP7631072B2 - Drive unit and construction machinery - Google Patents

Description

The present invention relates to a drive device and a construction machine.

For example, an electric construction machine that uses an electric motor as a drive source in consideration of the surrounding environment has been proposed (see, for example, Patent Document 1). In this machine, the electric motor drives a hydraulic pump, and various hydraulic actuators are driven by the hydraulic oil discharged from the hydraulic pump.
Among such electric construction machines using an electric motor as a drive source, there is known one equipped with a drive unit in which a hydraulic pump and an electric motor are provided for each of various hydraulic actuators. Here, a crawler-type power shovel, which is an example of a construction machine equipped with such a drive unit, is equipped with a boom, arm, and bucket as a working device (shovel mechanism), for example.

In the case of the drive device of this construction machine, the actuator that drives the boom is provided with a hydraulic pump for the boom and an electric motor for the boom. Also, the actuator that drives the arm is provided with a hydraulic pump for the arm and an electric motor for the arm. Furthermore, the actuator that drives the bucket is provided with a hydraulic pump for the bucket and an electric motor for the bucket.

In this drive device, the boom electric motor is driven to drive the boom actuator with the boom hydraulic pump to operate the boom. The arm electric motor is driven to drive the arm actuator with the arm hydraulic pump to operate the arm. The bucket electric motor is driven to drive the bucket actuator with the bucket hydraulic pump to operate the bucket.

JP 2007-284874 A

In some construction machines, the boom actuator, the arm actuator, or the bucket actuator may be operated independently. In such cases, the electric motor for the boom, the electric motor for the arm, or the electric motor for the bucket must maintain the maximum output when each actuator is operating independently. This requires a maximum required power for each actuator, and the total required power for each actuator inevitably increases.

Furthermore, the drive unit requires three electric motors (i.e., multiple electric motors): an electric motor for the boom, an electric motor for the arm, and an electric motor for the bucket. Thus, the drive unit has multiple electric motors, which is an obstacle to making the drive unit more compact.

The present invention provides a drive unit and construction machine that can reduce the size of the drive unit while suppressing the increase in the total power required to operate the work equipment.

A drive device according to one aspect of the present invention includes a plurality of actuators that are driven by the supply of a working fluid, a plurality of pumps that supply the working fluid to each of the actuators, a single drive source that transmits power to each of the pumps, and a power distributor that is provided in each power transmission path that transmits power from the single drive source to each of the pumps and distributes the power of the single drive source to the power required by each of the pumps.

With this configuration, the power of a single drive source is distributed by the power distributor, so that the power required by each of the multiple pumps can be secured. Therefore, for example, when each working member of the working device is operated independently, the maximum output when each of the multiple actuators is operated independently can be maintained (distributed) by a single drive source.
As a result, when the individual working members of the working device are operated independently, it is not necessary to use a plurality of drive sources to maintain the maximum output of each actuator when it is operating independently, as in the prior art.
Therefore, it is possible to suppress (avoid) an increase in the total required power required to operate the working device.

In addition, for example, when multiple working members of a working device are operated in a combined state, the power of a single drive source can be distributed by a power distributor, and the power required by each pump can be secured within the range of the power of the single drive source. Therefore, there is no need to provide multiple drive sources corresponding to multiple pumps, as in the conventional technology. This allows the number of drive sources to be reduced, and the drive device to be made more compact.

A drive device according to another aspect of the present invention includes a plurality of actuators that are driven by the supply of a working fluid, a plurality of variable displacement pumps that supply the working fluid to each of the plurality of actuators in response to the power required by each of the plurality of actuators, and a single drive source that transmits power to each of the plurality of variable displacement pumps.

With this configuration, the power of a single drive source is transmitted to each of the multiple variable displacement pumps, so that the multiple variable displacement pumps can secure the power required by each of the multiple actuators individually. Therefore, for example, when each working member of a working device is operated independently, the maximum output when each of the multiple actuators is operated independently can be maintained (distributed) by the single drive source.
As a result, when the individual working members of the working device are operated independently, it is not necessary to use a plurality of drive sources to maintain the maximum output of each actuator when it is operating independently, as in the prior art.
Therefore, it is possible to suppress (avoid) an increase in the total required power required to operate the working device.

In addition, for example, when multiple working members of a working device are operated in a combined state, the power of a single drive source can be distributed by multiple variable displacement pumps, and the power required by each actuator can be secured within the range of the power of the single drive source. Therefore, there is no need to provide multiple drive sources corresponding to multiple pumps, as in the conventional technology. This allows the number of drive sources to be reduced, and the drive device to be made more compact.

In the above configuration, the power distributor may be a plurality of transmissions that can vary the individual gear ratios of the plurality of pumps relative to the single drive source.

A drive device according to another aspect of the present invention includes a plurality of actuators that are driven by the supply of a working fluid, a plurality of pumps that supply the working fluid to each of the actuators, a single drive source that transmits power to each of the pumps, and a power distributor that is provided in each power transmission path that transmits power from the single drive source to each of the pumps and that can vary the individual gear ratios of the pumps relative to the single drive source so as to distribute the power to the power required by each of the pumps.

With this configuration, the gear ratios of the multiple pumps relative to the single drive source can be varied by the power distributor (i.e., the gearbox). Therefore, the power of the single drive source can be distributed to the multiple pumps as required by each of them. As a result, for example, when each working member of the working device is operated independently, the maximum output when each of the multiple actuators is operated independently can be maintained (distributed) by the single drive source.
Therefore, when the individual working members of the working device are operated independently, unlike the prior art, it is not necessary to maintain the maximum output of each actuator when it is operating independently using a plurality of drive sources.
As a result, it is possible to suppress (avoid) an increase in the total required power required to operate the working device.

In addition, for example, when multiple working members of a working device are operated in a combined state, the power of a single drive source can be distributed by a power distributor, and the power required by each pump can be secured within the range of the power of the single drive source. Therefore, there is no need to provide multiple drive sources corresponding to multiple pumps, as in the conventional technology. This allows the number of drive sources to be reduced, and the drive device to be made more compact.

A construction machine according to another aspect of the present invention includes a vehicle body and a drive unit mounted on the vehicle body for driving the vehicle body, the drive unit including a plurality of actuators driven by a supply of a working fluid, a plurality of pumps for supplying the working fluid to each of the actuators, a single drive source for transmitting power to each of the pumps, and a power distributor provided in each power transmission path for transmitting power from the single drive source to each of the pumps, for distributing the power of the single drive source to the power required by each of the pumps.

By configuring it in this way, it is possible to suppress (avoid) an increase in the total power required to operate the work equipment in the construction machine. In addition, it is possible to provide a construction machine in which the drive device can be made smaller by reducing the number of drive sources.

The present invention makes it possible to prevent the total power required to operate the drive unit and the work device in the construction machine from increasing, and to reduce the size of the drive unit.

1 is a schematic configuration diagram of a construction machine according to a first embodiment. FIG. 2 is a schematic configuration diagram of a drive device according to the first embodiment. FIG. 11 is a schematic configuration diagram of a drive device according to a second embodiment.

Next, a drive unit and construction machine according to an embodiment of the present invention will be described with reference to the drawings.

[First embodiment]
<Construction machinery>
FIG. 1 is a schematic configuration diagram of a construction machine 100 according to the first embodiment.
1, the construction machine 100 is, for example, a hydraulic excavator, etc. The construction machine 100 includes a revolving body (an example of a vehicle body in the claims) 101 and a running body 102 provided below the revolving body 101.

The rotating body 101 is equipped with a drive unit (one example of a drive unit in the claims) 1. The rotating body 101 is equipped with a cab 103, a boom 104 having one end connected to the cab 103, an arm 105 having one end connected to the other end of the boom 104, and a bucket 106 connected to the other end of the arm 105. The cab 103 supports an operator who rides on the rotating body 101. The boom 104 swings relative to the main body of the rotating body 101. The arm 105 swings relative to the boom 104. The bucket 106 swings relative to the arm 105. In other words, the boom 104, the arm 105, and the bucket 106 constitute a working device (shovel mechanism) of the construction machine 100.

The main part of the drive unit 1 is provided, for example, inside the rotating body 101. The hydraulic oil (an example of the hydraulic fluid in the claims) supplied from the drive unit 1 drives, for example, the boom 104, the arm 105, and the bucket 106.

<Drive unit>
FIG. 2 is a schematic configuration diagram of the drive device 1 according to the first embodiment.
As shown in Figures 1 and 2, the drive device 1 includes, for example, first to third hydraulic cylinders (an example of a plurality of actuators in the claims) 2, 3, and 4, first to third hydraulic pumps (an example of a plurality of pumps in the claims) 12, 13, and 14 that supply hydraulic oil to each of the hydraulic cylinders 2 to 4, a single electric motor (an example of a drive source in the claims) 15 that transmits power to each of the hydraulic pumps 12 to 14, and a power distributor (an example of a power distributor in the claims) 21 that distributes power from the electric motor 15 to each of the hydraulic pumps 12 to 14.

<Hydraulic cylinder>
The first hydraulic cylinder 2 is a boom actuator that operates the boom 104. A first hydraulic pump 12 is connected to a first cylinder end 2a and a first rod end 2b of the first hydraulic cylinder 2. The first hydraulic cylinder 2 operates the boom 104 in the direction of arrow A (see FIG. 1 ) by supplying hydraulic oil from the first hydraulic pump 12 to the first cylinder end 2a or the first rod end 2b.

The second hydraulic cylinder 3 is an actuator for the arm that operates the arm 105. The second hydraulic cylinder 3 has a second hydraulic pump 13 connected to the second cylinder end 3a and the second rod end 3b. The second hydraulic cylinder 3 operates the arm 105 in the direction of arrow B (see FIG. 1) by supplying hydraulic oil from the second hydraulic pump 13 to the second cylinder end 3a or the second rod end 3b.

The third hydraulic cylinder 4 is a bucket actuator that operates the bucket 106. The third hydraulic cylinder 4 has a third cylinder end 4a and a third rod end 4b connected to a third hydraulic pump 14. The third hydraulic cylinder 4 operates the bucket 106 in the direction of arrow C (see FIG. 1) by supplying hydraulic oil from the third hydraulic pump 14 to the third cylinder end 4a or the third rod end 4b.

<Hydraulic pump>
The first hydraulic pump 12 is a pump for the boom that operates the first hydraulic cylinder 2 for the boom. The first hydraulic pump 12 is connected to a single electric motor 15 via a power distributor 21. The first hydraulic pump 12 is driven by the power of the electric motor 15 transmitted via the power distributor 21. As the first hydraulic pump 12 is driven, hydraulic oil is supplied to the first cylinder end 2a or the first rod end 2b of the first hydraulic cylinder 2.

The second hydraulic pump 13 is a pump for the arm that operates the second hydraulic cylinder 3 for the arm. The second hydraulic pump 13 is connected to a single electric motor 15 via a power distributor 21. The second hydraulic pump 13 is driven by the power of the electric motor 15 being transmitted via the power distributor 21. When the second hydraulic pump 13 is driven, hydraulic oil is supplied to the second cylinder end 3a or the second rod end 3b of the second hydraulic cylinder 3.

The third hydraulic pump 14 is a pump for the bucket that operates the third hydraulic cylinder 4 for the bucket. The third hydraulic pump 14 is connected to a single electric motor 15 via a power distributor 21. The third hydraulic pump 14 is driven by the power of the electric motor 15 being transmitted via the power distributor 21. When the third hydraulic pump 14 is driven, hydraulic oil is supplied to the third cylinder end 4a or the third rod end 4b of the third hydraulic cylinder 4.

<Electric motor>
A single electric motor 15 (one) is provided in the drive device 1. The electric motor 15 is connected to a battery (not shown) provided in the revolving body 101, for example. The battery is set to a high voltage, for example. The electric motor 15 is driven by power supplied from the battery. As the electric motor 15, various electric motors such as a so-called brushed motor or a brushless motor can be used.
A motor shaft (not shown) of the electric motor 15 is connected to the first hydraulic pump 12, the second hydraulic pump 13, and the third hydraulic pump 14 via a power distributor 21. The power of the electric motor 15 is transmitted to the first hydraulic pump 12, the second hydraulic pump 13, and the third hydraulic pump 14 via the power distributor 21.

The first hydraulic pump 12, the second hydraulic pump 13, and the third hydraulic pump 14 are driven by the power transmitted from the electric motor 15. When the first hydraulic pump 12 is driven, a predetermined hydraulic pressure is supplied from the first hydraulic pump 12 to the first hydraulic cylinder 2. When the second hydraulic pump 13 is driven, a predetermined hydraulic pressure is supplied from the second hydraulic pump 13 to the second hydraulic cylinder 3. When the third hydraulic pump 14 is driven, a predetermined hydraulic pressure is supplied from the third hydraulic pump 14 to the third hydraulic cylinder 4.

<Power distributor>
The power distributor 21 is provided midway through a first power transmission path 22, a second power transmission path 23, and a third power transmission path 24 that transmit power from the single electric motor 15 to the first hydraulic pump 12, the second hydraulic pump 13, and the third hydraulic pump 14, respectively. Specifically, the power distributor 21 includes a first transmission 26, a second transmission 27, and a third transmission 28. The first transmission 26, the second transmission 27, and the third transmission 28 are examples of the multiple transmissions in the claims.

The first transmission 26 is provided in the middle of the first power transmission path 22, and as an example, a so-called planetary gear mechanism is used. That is, the first transmission 26 includes, for example, a sun gear, a plurality of planetary gears, an internal gear, and a carrier. The sun gear is connected to the motor shaft of the electric motor 15 so as to be capable of transmitting rotation. The output shaft of the first transmission 26 is connected to the drive shaft of the first hydraulic pump 12 so as to be capable of transmitting rotation.
The planetary gears are configured to be able to be set, for example, either orbital or non-revolutionary, the internal gear is configured to be set, for example, either rotational or non-rotational, and the carrier is configured to be set, for example, either rotational or non-rotational.

Here, an example will be described in which the first transmission 26 is operated in a state in which the plurality of planetary gears are set to revolve, the internal gear is set to non-rotate, and the carrier is set to rotate.
That is, by driving the electric motor 15, the sun gear of the first transmission 26 rotates integrally with the motor shaft. The rotation of the sun gear causes the multiple planetary gears to rotate on their own axes and revolve around the sun gear. The revolution of the multiple planetary gears rotates the carrier. The output shaft of the first transmission 26 rotates integrally with the carrier.
An output shaft of the first transmission 26 is connected to the drive shaft of the first hydraulic pump 12 so that rotation can be transmitted thereto. Thus, the first transmission 26 reduces the rotation of the electric motor 15 and transmits it to the drive shaft of the first hydraulic pump 12.

Here, according to the first transmission 26, by arbitrarily selecting the revolution/non-revolution of the multiple planetary gears, the rotation/non-rotation of the internal gear, and the rotation/non-rotation of the carrier, the revolution of the multiple planetary gears, the rotation of the internal gear, and the rotation of the carrier can be made to rotate the output shaft of the first transmission 26.
As a result, the first transmission 26 can change the speed of the electric motor 15 to decelerate the rotation and transmit the rotation to the drive shaft of the first hydraulic pump 12. In other words, the first transmission 26 can adjust the gear ratio with respect to the rotation of the electric motor 15.

The selection of whether the multiple planetary gears revolve or not, the internal gear rotates or not, and the carrier rotates or not, can be adjusted, for example, by an operating lever (not shown) of the control unit 31. The control unit 31 is composed of, for example, an operating lever and an operating pedal (not shown) provided inside the cab 103.

The second transmission 27 and the third transmission 28 are configured similarly to the first transmission 26. The second transmission 27 is provided in the middle of the second power transmission path 23, and is capable of changing the speed of the rotation of the electric motor 15 and transmitting it to the drive shaft of the second hydraulic pump 13. In other words, the second transmission 27 is capable of adjusting the gear ratio with respect to the rotation of the electric motor 15.
In addition, the third transmission 28 is provided in the middle of the third power transmission path 24, and is capable of changing the speed of the rotation of the electric motor 15 and transmitting it to the drive shaft of the third hydraulic pump 14. In other words, the third transmission 28 is capable of adjusting the gear ratio with respect to the rotation of the electric motor 15.

As described above, the power distributor 21 can adjust the gear ratios of the first transmission 26, the second transmission 27, and the third transmission 28 by the control unit 31. In other words, the power distributor 21 is configured so that the individual gear ratios of the first hydraulic pump 12, the second hydraulic pump 13, and the third hydraulic pump 14 relative to the single electric motor 15 can be varied by the control unit 31, such as an operating lever.
As a result, the power distributor 21 can distribute the power of the single electric motor 15 to the power required by each of the first hydraulic pump 12, the second hydraulic pump 13, and the third hydraulic pump 14.

<Clutch>
A main clutch 35, for example, is provided on the power transmission path between the electric motor 15 and the power distributor 21. The main clutch 35 transmits and cuts off the rotation of the electric motor 15 to the power distributor 21. In addition, a first clutch 36, for example, is provided on the first power transmission path 22 between the first transmission 26 and the first hydraulic pump 12. The first clutch 36 transmits and cuts off the rotation of the first transmission 26 to the first hydraulic pump 12.

A second clutch 37, for example, is provided in the second power transmission path 23 between the second transmission 27 and the second hydraulic pump 13. The second clutch 37 transmits or cuts off the rotation of the second transmission 27 to the second hydraulic pump 13.
A third clutch 38, for example, is provided in the third power transmission path 24 between the third transmission 28 and the third hydraulic pump 14. The third clutch 38 transmits or cuts off the rotation of the third transmission 28 to the third hydraulic pump 14.
The main clutch 35, the first clutch 36, the second clutch 37, and the third clutch 38 are switched between connection and disconnection by operating an operating lever or an operating pedal of the control unit 31, for example.

<Operation of the driving device>
Next, the operation of the drive device 1 will be described.
With the electric motor 15 in operation, the main clutch 35, the first clutch 36, the second clutch 37, and the third clutch 38 are switched between engagement and disengagement by operating the operation lever or operation pedal of the control unit 31. In addition, the gear ratios of the first transmission 26, the second transmission 27, and the third transmission 28 of the power distributor 21 are adjusted by operating the operation lever of the control unit 31.

Therefore, the power distributor 21 can distribute the power of the electric motor 15 to the power required by each of the first hydraulic pump 12, the second hydraulic pump 13, and the third hydraulic pump 14. This allows the first hydraulic pump 12, the second hydraulic pump 13, and the third hydraulic pump 14 to be driven by the power required by each of the hydraulic pumps 12, 13, and 14.
When the first hydraulic pump 12, the second hydraulic pump 13, and the third hydraulic pump 14 are driven, the first hydraulic cylinder 2, the second hydraulic cylinder 3, and the third hydraulic cylinder 4 are driven, and the boom 104, the arm 105, and the bucket 106 are operated.

In the construction machine 100, for example, the boom 104, the arm 105, or the bucket 106 may be operated independently. In this case, by switching only a single required clutch out of the first clutch 36, the second clutch 37, and the third clutch 38 to the connected state, the boom 104, the arm 105, and the bucket 106 can be operated independently as shown by arrows A, B, and C.

In addition, the construction machine 100 may operate, for example, the boom 104 and the arm 105 of the boom 104, arm 105, and bucket 106 in a combined state. In this case, the power of the single electric motor 15 can be distributed by the power distributor 21 (i.e., the first transmission 26 and the second transmission 27) to the power required by the boom 104 and the arm 105. Therefore, the boom 104 and the arm 105 can be operated in a combined state as shown by arrows A and B with the power of the single electric motor 15.

As described above, in the drive device 1 of the first embodiment, the power distributor 21 is capable of varying the gear ratios of the first transmission 26, the second transmission 27, and the third transmission 28. Therefore, the power of the single electric motor 15 can be distributed by the power distributor 21 (the first transmission 26, the second transmission 27, the third transmission 28) to the power required by each of the first hydraulic pump 12, the second hydraulic pump 13, and the third hydraulic pump 14.
In addition, the main clutch 35, the first clutch 36, the second clutch 37, and the third clutch 38 can be switched between connected and disconnected.

This ensures that the power required by each of the first hydraulic pump 12, the second hydraulic pump 13, and the third hydraulic pump 14 can be secured independently. As a result, when the boom 104, the arm 105, or the bucket 106 is operated independently, for example, the maximum output when each of the first hydraulic cylinder 2, the second hydraulic cylinder 3, and the third hydraulic cylinder 4 is operated independently can be maintained (distributed) by the single electric motor 15.

Therefore, when the boom 104, the arm 105, or the bucket 106 is operated independently, there is no need to maintain the maximum output of the first hydraulic cylinder 2, the second hydraulic cylinder 3, and the third hydraulic cylinder 4 when they are operating independently using multiple electric motors as in the prior art.
This makes it possible to suppress (avoid) an increase in the total power required to operate the boom 104, the arm 105, and the bucket 106.

In addition, for example, a plurality of working members may be selected from the boom 104, the arm 105, and the bucket 106 to operate in a combined state. In this case, the power of the single electric motor 15 is distributed by the power distributor 21 (i.e., the first transmission 26, the second transmission 27, and the third transmission 28), so that the power required by each of the hydraulic pumps 12, 13, and 14 can be secured within the power range of the single electric motor 15.
Therefore, unlike the conventional technology, it is not necessary to provide a plurality of electric motors 15 corresponding to the first hydraulic pump 12, the second hydraulic pump 13, and the third hydraulic pump 14. As a result, the number of electric motors 15 can be reduced to one, and the drive device 1 can be made more compact.

Furthermore, the drive unit 1 is mounted on a rotating body 101 provided on the construction machine 100. This makes it possible to prevent the total power required to operate the boom 104, arm 105, and bucket 106 from becoming too large, and furthermore, it is possible to obtain a construction machine 100 in which the number of electric motors 15 can be reduced to one, thereby enabling the drive unit 1 to be made more compact.

<Modification of power distributor>
Next, a modification of the power distributor will be described.
In the above embodiment, the first transmission 26, the second transmission 27, and the third transmission 28 are planetary gear mechanisms as the power distributor 21, but the present invention is not limited to this. As another example, the power distributor 21 may be a reducer or a transmission such as a commonly known eccentric oscillation type reduction unit or a continuously variable transmission unit.

The eccentric oscillating type reduction unit includes, for example, a cylindrical case, a carrier arranged radially inside the case, and a reduction output unit that rotates the carrier at a rotation speed that is reduced at a fixed ratio to the rotation speed of the motor shaft of the electric motor 15. The reduction output unit includes, for example, multiple crankshafts, and a first external gear and a second external gear that rotate in an oscillating manner in conjunction with the rotation of the crankshafts. The reduction output unit reduces the rotation of the multiple crankshafts and transmits it to the carrier, causing the carrier to rotate at a reduced speed relative to the motor shaft of the electric motor 15.

This eccentric oscillating type reduction section may be used as the first reduction section, the second reduction section, and the third reduction section instead of the first transmission 26, the second transmission 27, and the third transmission 28 of the first embodiment. The first reduction section, the second reduction section, and the third reduction section have reduction ratios set so that the power of the single electric motor 15 can be distributed to the power required by each of the first hydraulic pump 12, the second hydraulic pump 13, and the third hydraulic pump 14. In other words, even when an eccentric oscillating type reduction section is provided as the power distributor 21, the same effects as those of the first embodiment can be obtained.

The continuously variable transmission unit includes a pair of first pulleys provided on the motor shaft side of the electric motor 15, a pair of second pulleys provided on the shaft on the hydraulic pump side, and a drive belt stretched between the pair of first pulleys and the pair of second pulleys. The continuously variable transmission unit changes the width of the pair of first pulleys and the width of the pair of second pulleys. This changes the sliding position of the drive belt in contact with the pair of first pulleys and the pair of second pulleys, thereby changing the gear ratio continuously.

This continuously variable transmission may be used as the first, second, and third transmissions instead of the first transmission 26, second transmission 27, and third transmission 28 of the first embodiment. The first, second, and third transmissions have a gear ratio set so that the power of the single electric motor 15 can be distributed to the power required by each of the first hydraulic pump 12, second hydraulic pump 13, and third hydraulic pump 14. In other words, even when the continuously variable transmission is provided as the power distributor 21, the effect of the first embodiment can be obtained.

The power distributor 21 can take various forms. It is sufficient for the power distributor 21 to be configured to distribute the power of a single drive source (e.g., the electric motor 15) to the power required by each of the hydraulic pumps 12 to 14.

[Second embodiment]
<Drive unit>
Next, a drive device 50 according to a second embodiment will be described with reference to Fig. 3. In the second embodiment, the same or similar members as those in the drive device 1 according to the first embodiment will be denoted by the same reference numerals and detailed description thereof will be omitted.
FIG. 3 is a schematic diagram of a drive device 50 according to the second embodiment.
As shown in FIG. 3, the drive device 50 includes a first variable displacement pump 52, a second variable displacement pump 53, and a third variable displacement pump 54, instead of the first hydraulic pump 12, the second hydraulic pump 13, the third hydraulic pump 14, and the power distributor 21 of the first embodiment.
The first variable displacement pump 52, the second variable displacement pump 53, and the third variable displacement pump 54 are examples of a plurality of variable displacement pumps in the claims.

<Variable displacement pump>
The first variable displacement pump 52 is, for example, a boom piston pump that operates the first hydraulic cylinder 2 for the boom. The first variable displacement pump 52 has a drive shaft rotatably connected to the motor shaft of the single electric motor 15 via a first power transmission path 22. The first variable displacement pump 52 is driven by the power (rotation) of the electric motor 15 being transmitted thereto. As the first variable displacement pump 52 is driven, hydraulic oil is supplied to the first cylinder end 2a or the first rod end 2b of the first hydraulic cylinder 2.

The first variable displacement pump 52 can vary the supply of hydraulic oil steplessly in the range from zero to the maximum discharge amount, for example, by operating an operating lever (not shown) of the control unit 31 to change the inclination angle (tilt angle) of the swash plate connected to the piston. Therefore, the first variable displacement pump 52 can supply hydraulic oil to the first hydraulic cylinder 2 corresponding to the power required by the first hydraulic cylinder 2. As a result, by supplying hydraulic oil from the first variable displacement pump 52 to the first hydraulic cylinder 2, the power required by the first hydraulic cylinder 2 can be secured for the power of a single electric motor 15.

The second variable displacement pump 53 is, for example, a piston pump for the arm that operates the second hydraulic cylinder 3 for the arm. The drive shaft of the second variable displacement pump 53 is rotatably connected to a single electric motor 15 via a second power transmission path 23. The second variable displacement pump 53 is driven by the power (rotation) of the electric motor 15 being transmitted thereto. When the second variable displacement pump 53 is driven, hydraulic oil is supplied to the second cylinder end 3a or the second rod end 3b of the second hydraulic cylinder 3.

The second variable displacement pump 53 can vary the supply of hydraulic oil steplessly in the range from zero to the maximum discharge amount, for example, by operating an operating lever (not shown) of the control unit 31 to change the inclination angle of the swash plate connected to the piston. Therefore, the second variable displacement pump 53 can supply hydraulic oil to the second hydraulic cylinder 3 corresponding to the power required by the second hydraulic cylinder 3. As a result, by supplying hydraulic oil from the second variable displacement pump 53 to the second hydraulic cylinder 3, the power required by the second hydraulic cylinder 3 for the power of a single electric motor 15 can be secured.

The third variable displacement pump 54 is, for example, a bucket piston pump that operates the third hydraulic cylinder 4 for the bucket. The third variable displacement pump 54 has a drive shaft rotatably connected to a single electric motor 15 via a third power transmission path 24. The third variable displacement pump 54 is driven by the transmission of power (rotation) of the electric motor 15. When the third variable displacement pump 54 is driven, hydraulic oil is supplied to the third cylinder end 4a or the third rod end 4b of the third hydraulic cylinder 4.

The third variable displacement pump 54 can vary the supply of hydraulic oil steplessly in the range from zero to the maximum discharge amount, for example, by operating an operating lever (not shown) of the control unit 31 to change the inclination angle of the swash plate connected to the piston. Therefore, the third variable displacement pump 54 can supply hydraulic oil to the third hydraulic cylinder 4 corresponding to the power required by the third hydraulic cylinder 4. As a result, by supplying hydraulic oil from the third variable displacement pump 54 to the third hydraulic cylinder 4, the power required by the third hydraulic cylinder 4 can be secured in response to the power of a single electric motor 15.

In this way, the power of the single electric motor 15 is transmitted to each of the first variable displacement pump 52, the second variable displacement pump 53, and the third variable displacement pump 54. Furthermore, the first variable displacement pump 52, the second variable displacement pump 53, and the third variable displacement pump 54 can distribute the power of the single electric motor 15 to the power required by each of the first hydraulic cylinder 2, the second hydraulic cylinder 3, and the third hydraulic cylinder 4.

<Operation of the driving device>
Next, the operation of the driving device 50 will be described.
With the electric motor 15 in a driven state, the tilt angles of the swash plates of the first variable displacement pump 52, the second variable displacement pump 53, and the third variable displacement pump 54 are changed (adjusted) by operating the operation lever of the control unit 31. Therefore, the first variable displacement pump 52, the second variable displacement pump 53, and the third variable displacement pump 54 can distribute the power of the electric motor 15 to the power required by each of the first hydraulic cylinder 2, the second hydraulic cylinder 3, and the third hydraulic cylinder 4.
As a result, the first hydraulic pump 12, the second hydraulic pump 13, and the third hydraulic pump 14 are driven, thereby driving the first hydraulic cylinder 2, the second hydraulic cylinder 3, and the third hydraulic cylinder 4, and the boom 104, the arm 105, and the bucket 106 are operated.

Incidentally, the construction machine 100 may operate, for example, the boom 104, the arm 105, or the bucket 106 independently. In this case, the inclination angle of the swash plates of the first variable displacement pump 52, the second variable displacement pump 53, and the third variable displacement pump 54 is controlled by the control lever of the control unit 31 to vary the supply of hydraulic oil by each of the variable displacement pumps 52, 53, and 54 to zero or maximum discharge. This allows the boom 104, the arm 105, and the bucket 106 to operate independently as indicated by arrows A, B, and C (see FIG. 1).

In addition, the construction machine 100 may operate, for example, the boom 104 and the arm 105 of the boom 104, arm 105, and bucket 106 in a combined state. In this case, the power of the single electric motor 15 can be distributed by the first variable displacement pump 52 and the second variable displacement pump 53 to the power required by the boom 104 and the arm 105. Therefore, the boom 104 and the arm 105 can be operated in a combined state as indicated by arrows A and B (see FIG. 1) using the power of the single electric motor 15.

As described above, in the drive device 50 of the second embodiment, the power of the single electric motor 15 is transmitted to each of the first variable displacement pump 52, the second variable displacement pump 53, and the third variable displacement pump 54. Furthermore, the first variable displacement pump 52, the second variable displacement pump 53, and the third variable displacement pump 54 are capable of securing the power required by each of the first hydraulic cylinder 2, the second hydraulic cylinder 3, and the third hydraulic cylinder 4 individually.
Therefore, the same effects as those of the first embodiment described above can be achieved.

The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above embodiment, a shovel mechanism including the boom 104, the arm 105, and the bucket 106 is exemplified as the working device of the construction machine 100. However, this is not limited to this, and the working device of the construction machine can be applied to working devices other than the boom 104, the arm 105, and the bucket 106.

In the above embodiment, the electric motor 15 is used as the drive source, but this is not limited to the above. Anything that can serve as a drive source for each of the hydraulic pumps 12-14 and each of the variable displacement pumps 52-54 can be used. For example, an engine can be used as the drive source instead of the electric motor 15.

In addition, the components of the above-described embodiment may be replaced with well-known components without departing from the spirit of the present invention. In addition, the above-described variations may be combined.

1, 50... Drive device 2... First hydraulic cylinder (actuator)
3...Second hydraulic cylinder (actuator)
4...Third hydraulic cylinder (actuator)
12...First hydraulic pump (pump)
13...Second hydraulic pump (pump)
14...Third hydraulic pump (pump)
15...Electric motor (drive source)
21...power distributor 26...first transmission (transmission)
27...Second transmission (transmission)
28...Third gear (gear)
52...First variable displacement pump (variable displacement pump)
53...Second variable displacement pump (variable displacement pump)
54...Third variable displacement pump (variable displacement pump)
100... Construction machine 101... Rotating body (vehicle body)

Claims (2)

A plurality of actuators that are actuated by the supply of a working fluid;
a plurality of pumps each supplying the hydraulic fluid to each of the plurality of actuators;
a single drive source that transmits power to each of the plurality of pumps;
a power distributor that is provided in each of the power transmission paths that transmits power from the single driving source to each of the plurality of pumps, and distributes the power of the single driving source to the power required by each of the plurality of pumps;
Equipped with
The power distributor includes:
a plurality of transmissions each capable of varying a gear ratio of each of the plurality of pumps relative to the single drive source,
Each of the transmissions is
a sun gear to which the power of the drive source is transmitted;
a plurality of planetary gears meshed with the sun gear;
a planetary carrier that rotatably supports the plurality of planetary gears;
an internal gear that is arranged coaxially with the sun gear and has internal teeth that mesh with the planetary gear;
Preparation,
The planetary gear is provided so as to be switchable between revolution around the sun gear and non-revolution,
The internal gear is provided so as to be switchable between rotation and non-rotation,
The rotation of either the planetary carrier or the internal gear is transmitted to the corresponding pump;
A control unit for switching between revolution and non-revolution of the planetary gear and rotation and non-rotation of the internal gear is provided.
Drive unit. The car body and
a drive device mounted on the vehicle body and configured to drive the vehicle body;
The drive device is
A plurality of actuators that are actuated by the supply of a working fluid;
a plurality of pumps each supplying the hydraulic fluid to each of the plurality of actuators;
a single drive source that transmits power to each of the plurality of pumps;
a power distributor that is provided in each of the power transmission paths that transmits power from the single driving source to each of the plurality of pumps, and distributes the power of the single driving source to the power required by each of the plurality of pumps;
Equipped with
The power distributor includes:
a plurality of transmissions each capable of varying a gear ratio of each of the plurality of pumps relative to the single drive source,
Each of the transmissions is
a sun gear to which the power of the drive source is transmitted;
a plurality of planetary gears meshed with the sun gear;
a planetary carrier that rotatably supports the plurality of planetary gears;
an internal gear that is arranged coaxially with the sun gear and has internal teeth that mesh with the planetary gears;
Preparation,
The planetary gear is provided so as to be switchable between revolution around the sun gear and non-revolution,
The internal gear is provided so as to be switchable between rotation and non-rotation,
The rotation of either the planetary carrier or the internal gear is transmitted to the corresponding pump;
A control unit for switching between revolution and non-revolution of the planetary gear and rotation and non-rotation of the internal gear is provided.
Construction machinery.

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