JP2010048366A - Hydraulic system and construction machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic system capable of improving an energy saving effect by regenerating the power of an actuator. <P>SOLUTION: In the hydraulic system, a first motor 32 drives a first hydraulic pump 33, and a boom cylinder 17 is driven by hydraulic fluid delivered from the first hydraulic pump 33. When the boom cylinder is driven in a tare direction and a third hydraulic pump 41 is not operating, a vehicle controller positions a first changeover valve 47 in a regenerating operating position S22, and a second changeover valve 48 in a regeneration operating position S32. Thereby, the hydraulic fluid output from the boom cylinder 17 is sequentially sent through the second changeover valve 48, a regeneration line 50, the first changeover valve 47, and the third hydraulic pump 41 and returned to a tank 8. At that time, an electric motor-cum-generator 40 functions as a generator, and electricity generated by the electric motor-cum-generator 40 is stored in a battery 22. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a hydraulic apparatus, and also relates to a construction machine such as a hydraulic excavator, a crane, a bulldozer, and a pile driving machine.

  Conventionally, as an electro-hydraulic hybrid excavator, a parallel type and a series type are known.

  The parallel hydraulic device includes a generator / motor installed between an engine and a hydraulic pump. This generator / motor is directly connected coaxially to the engine and the hydraulic pump, and is used as a generator when the engine load is low, and the generated electricity is stored. When the load on the engine increases, the generator / motor assists the engine by driving the hydraulic pump using the electricity stored when the engine is under low load.

  In the series type hydraulic device, the generator is directly connected to the engine, and all the power of the engine is used for power generation by the generator. And the electric motor directly connected to the hydraulic pump is driven using the electricity generated by the generator.

  One such series-type hydraulic device is described in Japanese Patent Application Laid-Open No. 2003-155760 (Patent Document 1). This hydraulic apparatus includes a plurality of sets of a hydraulic pump and an electric motor that drives the hydraulic pump, and drives all the electric motors with electricity generated by the generator.

  By the way, in the hydraulic device of the above-mentioned patent document 1, if a motor that is not used among a plurality of motors is stopped, energy that is wasted can be reduced, but there is no function of regenerating the power of the actuator.

Therefore, the hydraulic device of Patent Document 1 has a problem that energy is wasted and the energy saving effect is low.
JP 2003-155760 A

  Therefore, an object of the present invention is to provide a hydraulic device that can regenerate the power of the hydraulic actuator and enhance the energy saving effect.

  Moreover, the other subject of this invention is providing the construction machine provided with such a hydraulic device.

In order to solve the above problems, the hydraulic device of the present invention is
A hydraulic pump;
An electric motor for driving the hydraulic pump;
An actuator driven by hydraulic oil discharged from the hydraulic pump;
A regenerative device for regenerating the power of the actuator;
A power storage device for storing electric power regenerated by the regenerative device;
And a control device for controlling the regenerative device based on an operating state of the hydraulic pump.

  According to the hydraulic apparatus having the above-described configuration, the hydraulic pump is driven by an electric motor and discharges hydraulic oil. The actuator is driven by this hydraulic oil. At this time, the control device controls the regenerative device based on the operating state of the hydraulic pump. For example, when the control device determines that the hydraulic pump is in the standby state, the power of the actuator is regenerated by the regenerative device.

  Therefore, by storing the electric power regenerated by the regenerative device in the power storage device, the power of the actuator is not wasted and the energy saving effect can be enhanced.

In the hydraulic device of one embodiment,
The control device
Operation determining means for determining whether or not the hydraulic pump is operating;
When the operation determining means determines that the hydraulic pump is not operating, the operation determining means includes first regeneration control means for causing the regenerative device to regenerate the power of the actuator.

  According to the hydraulic device of the above embodiment, the first regeneration control means causes the regeneration device to regenerate the power of the actuator when the operation determining means determines that the hydraulic pump is not operating. A hydraulic pump can be used for regeneration.

In the hydraulic device of one embodiment,
The control device
Power storage determination means for determining whether or not power can be stored in the power storage device;
And a second regenerative control unit that causes the regenerative device to regenerate the power of the actuator when the power storage determining unit determines that the power can be stored in the power storage device.

  According to the hydraulic device of the above embodiment, when it is determined by the power storage determination means that power can be stored in the power storage device, the second regeneration control means causes the regeneration device to regenerate the power of the actuator. The regenerated electric power can be reliably stored in the power storage device.

In the hydraulic device of one embodiment,
The regenerative device includes a switching valve for allowing hydraulic oil to flow from the actuator to the electric motor.

  According to the hydraulic device of the above embodiment, since the regenerative device includes a switching valve for allowing hydraulic oil to flow from the actuator to the electric motor, the hydraulic oil is sent from the actuator to the electric motor, and electricity is generated by the electric motor. It can generate electricity.

  Therefore, by storing the power of the actuator as electrical energy in the power storage device, an energy saving effect can be obtained using the electrical energy when necessary.

The construction machine of the present invention is
A swivel,
A working arm attached to the revolving body so as to be vertically rotatable;
Comprising the hydraulic device of the present invention,
The regenerative device of the hydraulic device is characterized in that the electric motor is driven by hydraulic oil that has come out of the actuator when the work arm rotates by its own weight downward in the vertical direction.

  According to the construction machine having the above-described configuration, the regenerative device of the hydraulic device generates electric power because it drives the electric motor with the hydraulic oil discharged from the actuator when the work arm rotates under the vertical direction under its own weight. Can do.

  Therefore, by storing the power of the actuator as electrical energy in the power storage device, an energy saving effect can be obtained using the electrical energy when necessary.

  According to the hydraulic device of the present invention, by providing the control device that controls the regenerative device based on the operating state of the hydraulic pump, when the hydraulic pump is not operating, the power of the actuator is regenerated to the regenerative device. The energy saving effect can be enhanced.

  According to the construction machine of the present invention, the regenerative device of the hydraulic device drives the electric motor with the hydraulic oil discharged from the actuator when the work arm rotates downward in the vertical direction under its own weight, thereby Can be converted into electric energy by an electric motor, and the electric energy can be stored in the power storage device. Therefore, when necessary, the electric energy can be used to obtain an energy saving effect.

  Hereinafter, the hydraulic apparatus of the present invention will be described in detail with reference to the illustrated embodiments.

  FIG. 1 is a schematic perspective view of a hybrid excavator 1 according to an embodiment of the present invention.

  The hybrid excavator 1 includes a lower traveling body 2, an upper revolving body 3 that is turnably mounted on the lower traveling body 2, an excavation work machine 4 that is attached to the upper revolving body 3 and performs excavation work and the like. It has. The lower traveling body 2 and the upper swing body 3 constitute a vehicle body of the hybrid excavator 1. The upper swing body 3 is an example of a swing body, and the excavation work machine 4 is an example of a work arm. In the following description, unless otherwise specified, “front side”, “rear side”, “left side”, and “right side” mean the front side, the rear side, the left side, and the right side with respect to the lower traveling body 2, respectively.

  The lower traveling body 2 is provided with a traveling crawler 5 and a blade 6 for performing leveling work and the like. The lower traveling body 2 is provided with a traveling hydraulic motor 15 for driving the crawler 5 and a blade cylinder 16 for driving the blade 6. The hydraulic motor 15 and the blade cylinder 16 are examples of actuators.

  The upper swing body 3 has a swing motor 13 for swinging with respect to the lower traveling body 2. The upper swing body 3 is provided with an operator cabin 7. A tank 8 containing hydraulic oil is installed on the rear side of the operator cabin 7. A machine cab 9 is installed on the right side of the operator cabin 7. Although not shown, a pinion gear is attached to the tip of the drive shaft of the swing electric motor 13, and the pinion gear and the internal gear single row ring gear fixed to the lower traveling body are mutually connected. Match.

  The excavator 4 includes a boom 10 whose base end is connected to the upper swing body 3 so as to be rotatable in the vertical direction, an arm 11 connected to the tip of the boom 10 so as to be rotatable, 11 and a bucket 12 that is rotatably connected to the tip end portion. The excavator 4 is provided with a boom cylinder 17 for driving the boom 10, an arm cylinder 18 for driving the arm 11, and a bucket cylinder 19 for driving the bucket 12. . The boom cylinder 17, the arm cylinder 18, and the bucket cylinder 19 are examples of actuators.

  One end of the boom cylinder 17 is rotatably supported by the upper swing body 3, and the tip of the rod 17 a, which is the other end, is rotatably connected to the base end portion of the boom 10. Is rotated (raised) around the base end.

  One end of the arm cylinder 18 is pivotally supported on the upper surface of the boom 10, and the other end of the rod 18 a is pivotally connected to the arm 11. Rotate around the connecting shaft.

  One end of the bucket cylinder 19 is rotatably supported on the front surface of the arm 11, and the tip of the rod 19 a, which is the other end, is rotatably connected to the bucket 12. Rotate around the connecting shaft.

  FIG. 2 is a schematic diagram showing a configuration of a main part of the hybrid excavator 1.

  The hybrid excavator 1 includes an engine 20, a generator 21 driven by the engine 20, a battery 22 that stores electricity generated by the generator 21, and a hydraulic device 23. The battery 22 is an example of a power storage device.

  The hydraulic device 23 includes a vehicle controller 24, a first unit 25, a second unit 26, a third unit 27, a regenerative device 28, and a multi-valve 29. The vehicle controller 24 is an example of a control device.

  The first unit 25 includes a first inverter 31 that receives an operation signal from the first operation lever 30, a variable-speed first motor 32 that is supplied with a current adjusted by the first inverter 31, and the first unit 25. And a variable capacity first hydraulic pump 33 driven by the electric motor 32.

  The first operation lever 30 is provided in the operator cabin 7. The operator operates the first operation lever 30 when driving the boom 10 and the bucket 12.

  The second unit 26 includes a second inverter 35 that receives an operation signal from the second operation lever 34, a variable-speed second electric motor 36 that is supplied with a current adjusted by the second inverter 35, and a second And a variable capacity second hydraulic pump 37 driven by the electric motor 36.

  The second operation lever 34 is provided in the operator cabin 7. The operator operates the second operation lever 34 when driving the arm 11.

  The third unit 27 includes a third inverter 39 that receives an operation signal from the third operation lever 38, a variable-speed electric motor / generator 40 to which a current adjusted by the third inverter 39 is supplied, and the electric motor And a fixed capacity third hydraulic pump 41 driven by the cum generator 40. The electricity generated by the motor / generator 40 is stored in the battery 22.

  The third operation lever 38 is provided in the operator cabin 7. The operator operates the third operation lever 38 when driving the blade 6.

  The vehicle controller 24 is connected to the first inverter 31, the second inverter 35 and the third inverter 39, and can detect the operating states of the first inverter 31, the second inverter 35 and the third inverter 39. In the vehicle controller 24, the first hydraulic pump 33, the second hydraulic pump 37, and the third hydraulic pump 41 are operated based on the operating states of the first inverter 31, the second inverter 35, and the third inverter 39. It can be determined whether or not.

  The multi-valve 29 includes a travel operation valve 42, a blade operation valve 43, a boom cylinder operation valve 44, an arm operation valve 45, and a bucket operation valve 46. Each of these valves is controlled to be opened and closed by the vehicle controller 24. For example, when the boom cylinder operation valve 44 is opened, the hydraulic oil discharged from the first hydraulic pump 33 is directed to the boom cylinder 17 through the boom cylinder operation valve 44. When the arm operation valve 45 is opened, the hydraulic oil discharged from the second hydraulic pump 37 passes through the arm operation valve 45 toward the arm cylinder 18.

  A first switching valve 47 is installed between the multi-valve 29 and the third hydraulic pump 41. By switching the first switching valve 47, hydraulic oil can flow from the third hydraulic pump 41 to the multi-valve 29, or hydraulic oil can flow from the multi-valve 29 to the third hydraulic pump 41. That is, the first switching valve 47 can switch the flow of hydraulic oil between the third hydraulic pump 41 and the multi-valve 29. The first switching valve 47 is an example of a switching valve.

  FIG. 3 is a hydraulic circuit diagram of the main part of the hydraulic device 23. In FIG. 3, illustration of some components is omitted.

  The hydraulic device 23 includes a first switching valve 47, a second switching valve 48 installed between the boom cylinder 17 and the boom cylinder operation valve 44, and a regenerative power generation that receives a control signal from the vehicle controller 24. And an electromagnetic valve 49. The second switching valve 48 is an example of a switching valve.

  The boom cylinder operation valve 44 receives a pilot pressure by the operation of the first operation lever 30 and switches its position. More specifically, when the position of the boom cylinder operation valve 44 is the standby position S0, the hydraulic oil discharged from the first hydraulic pump 33 returns to the tank 8 without going to the boom cylinder 17. When the position of the boom cylinder operation valve 44 reaches the boom raising position S1, hydraulic oil is supplied from the first hydraulic pump 33 to the boom cylinder 17, and the boom 10 rotates upward in the vertical direction. On the other hand, when the position of the boom cylinder operation valve 44 reaches the boom lowering position S2, hydraulic oil is supplied from the first hydraulic pump 33 to the boom cylinder 17, and the boom 10 rotates downward in the vertical direction. At this time, the flow of the hydraulic oil is opposite to the flow of the hydraulic oil when the position of the boom cylinder operation valve 44 is at the boom raising position S1.

  The regenerative power generation electromagnetic valve 49 is controlled by the vehicle controller 24 so that the position of the regenerative power generation electromagnetic valve 49 becomes the normal operation position S11 during operation of the boom 10. The regenerative power generation electromagnetic valve 49 is controlled so that the position is at the regenerative operation position S12 when the power of the boom 10 is regenerated. When the position of the regenerative power generation electromagnetic valve 49 becomes the regenerative operation position S12, the pilot pressure is applied to the first switching valve 47 and the second switching valve 48, and the position of the first switching valve 47 changes from the normal operation position S21 to the regenerative operation position. While switching to S22, the position of the second switching valve 48 is switched from the normal operation position S31 to the regenerative operation position S32. As a result, the hydraulic oil that has exited the boom cylinder 17 sequentially flows through the second switching valve 48, the regeneration line 50, the first switching valve 47, and the third hydraulic pump 41 and returns to the tank 8. At this time, the electric motor / generator 40 functions as a generator, and electricity generated by the electric motor / generator 40 is stored in the battery 22.

  Hereinafter, the regenerative power generation control performed by the vehicle controller 24 will be described using the flowchart of FIG.

  First, in step S1, it is determined whether or not the operator is performing a lowering operation of the boom 10. If it is determined in step S1 that the operator is performing the lowering operation of the boom 10, the process proceeds to the next step S2. On the other hand, when it is not determined in step S1 that the operator is performing the lowering operation of the boom 10, the process proceeds to step S5.

  When the process proceeds to step S5, the regenerative power generation electromagnetic valve 49 is turned OFF, and the hydraulic circuit of the hydraulic device 23 is changed to a normal circuit. That is, the position of the regenerative power generation electromagnetic valve 49 is set to the normal operation position S11 so that the hydraulic oil discharged from the boom cylinder 17 flows toward the boom cylinder operation valve 44.

  Here, the lowering operation of the boom 10 is an operation of rotating the boom 10 downward in the vertical direction. Whether or not the boom 10 is being lowered is determined based on an operation signal output from the first operation lever 30.

  Next, in step S2, it is determined whether or not the third hydraulic pump 41 of the third unit 27 is operating. If it is determined in step S2 that the third hydraulic pump 41 of the third unit 27 is not operating, the process proceeds to the next step S3. On the other hand, if it is determined in step S2 that the third hydraulic pump 41 of the third unit 27 is operating, the process proceeds to step S5 described above.

  Next, in step S3, it is determined whether or not the battery 22 is empty. If it is determined in this step S3 that the battery 22 is empty, the process proceeds to the next step S4. On the other hand, if it is determined in step S3 that the battery 22 is not empty, the process proceeds to step S5 described above.

  Finally, in step S <b> 4, the regenerative power generation electromagnetic valve 49 is turned on, and the third unit 27 performs regenerative power generation. That is, the position of the regenerative power generation electromagnetic valve 49 is set to the regenerative operation position S12, the hydraulic oil exiting the boom cylinder 17 is caused to flow to the third hydraulic pump 41, and the motor / generator 40 functions as a power generator.

  By performing such regenerative power generation control, when the boom 10 is driven downward in the vertical direction under its own weight, the regenerative device 28 regenerates the power of the boom cylinder 17, and the regenerated electric power is supplied to the battery 22. Stored.

  Therefore, the power of the boom cylinder 17 is not wasted, and the energy saving effect can be enhanced by using the power of the battery 22 when necessary.

  Further, when it is determined in step S2 that the third hydraulic pump 41 is not in operation, the power of the boom cylinder 17 is regenerated, so that the third hydraulic pump 41 can be used for the regeneration.

  Further, when it is determined in step S3 that the battery 22 is empty, power regeneration of the boom cylinder 17 is performed. That is, if the battery 22 is not empty, power regeneration of the boom cylinder 17 is performed. I will not.

  Therefore, the electric power obtained by regenerating the power of the boom cylinder 17 can be reliably stored in the battery 22.

  In the above embodiment, an example of the operation determination unit is configured by Step S2, an example of the storage determination unit is configured by Step S3, and an example of the first and second regeneration control units is configured by Step S4. .

  In the above embodiment, the power of the boom cylinder 17 is regenerated. However, for example, the power of the arm cylinder 18 or the bucket 12 may be regenerated.

  In the above embodiment, when it is determined in step S2 that the third hydraulic pump 41 is not operating, and it is determined in step S3 that the battery 22 is empty, the power regeneration of the boom cylinder 17 is regenerated. However, if it is determined in step S2 that the third hydraulic pump 41 is not operating, the power of the boom cylinder 17 may be regenerated following the determination. That is, the battery 22 empty determination in step S3 may be omitted.

  In the above embodiment, an example in which the hydraulic device 23 according to the embodiment of the present invention is applied to a hybrid excavator has been described. You may apply.

FIG. 1 is a schematic perspective view of a hybrid excavator according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing a configuration of a main part of the hybrid excavator. FIG. 3 is a hydraulic circuit diagram of a main part of the hydraulic apparatus according to the embodiment of the present invention. FIG. 4 is a flowchart of regenerative power generation control of the hydraulic device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hybrid excavator 3 Upper turning body 4 Excavation work machine 15 Hydraulic motor 16 Blade cylinder 17 Boom cylinder 18 Arm cylinder 19 Bucket cylinder 22 Battery 23 Hydraulic device 24 Vehicle controller 28 Regenerative device 40 Electric motor / generator 41 3rd hydraulic pump 47 1st Switching valve 48 Second switching valve

Claims (5)

A hydraulic pump (33, 37, 41);
An electric motor (32, 36, 40) for driving the hydraulic pump (33, 37, 41);
Actuators (15, 16, 17, 18, 19) driven by hydraulic oil discharged from the hydraulic pumps (33, 37, 41);
A regeneration device (28) for regenerating the power of the actuator (17);
A power storage device (22) for storing electric power regenerated by the regenerative device (28);
A hydraulic device comprising: a control device (24) for controlling the regenerative device (28) based on an operating state of the hydraulic pump (41). The hydraulic device according to claim 1,
The control device (24)
An operation determining means (S2) for determining whether or not the hydraulic pump (41) is operating;
When the operation determination means (S2) determines that the hydraulic pump (41) is not operating, the first regeneration control means (S4) causes the regeneration device (28) to regenerate the power of the actuator (17). And a hydraulic device. The hydraulic device according to claim 1 or 2,
The control device (24)
Power storage determination means (S3) for determining whether or not power can be stored in the power storage device (22);
When the power storage determination means (S3) determines that it is possible to store power in the power storage device (22), the regenerative device (28) regenerates the power of the actuator (17). A hydraulic apparatus comprising control means (S4). The hydraulic apparatus according to any one of claims 1 to 3,
The regenerative device (28) includes a switching valve (47, 48) for allowing hydraulic oil to flow from the actuator (17) to the electric motor (40). Revolving body (3),
A working arm (4) attached to the revolving body (3) so as to be rotatable in a vertical direction;
A hydraulic device (23) according to any one of claims 1 to 4,
The regenerative device (28) of the hydraulic device (23) is configured such that when the work arm (4) is rotated by its own weight and downward in the vertical direction, the electric motor ( 40) A construction machine characterized by driving.

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