WO2015151721A1

WO2015151721A1 - Hybrid work machine

Info

Publication number: WO2015151721A1
Application number: PCT/JP2015/056682
Authority: WO
Inventors: 貢小島; 秀二江川; 泰典太田
Original assignee: 日立建機株式会社
Priority date: 2014-04-03
Filing date: 2015-03-06
Publication date: 2015-10-08
Also published as: JP2015197030A; JP6270596B2

Abstract

A hydraulic shovel (1) that is a hybrid-type work machine comprises: a hydraulic pump (14) that discharges pressurized oil and that is driven by an engine (9); a hydraulic oil tank (20) that stores hydraulic oil to be supplied to a hydraulic actuator that includes a swing motor (19) and a boom cylinder (5B); a regenerative hydraulic motor (23) that rotates by way of return oil that is returned from the hydraulic actuators to the hydraulic oil tank (20); and a regenerative electric motor (24) that generates power to be stored in an electrical storage device (13) by way of being driven by the regenerative hydraulic motor (23). The hydraulic oil tank (20) is provided on a swing frame (6) located on the front side of the hydraulic pump (14), and the regenerative hydraulic motor (23) and the regenerative electric motor (24) that constitute a regenerative unit (25) are disposed in the vicinity of the hydraulic oil tank (20).

Description

Hybrid work machine

The present invention relates to a work machine such as a hydraulic excavator or a wheel-type hydraulic excavator, and more particularly to a hybrid work machine that uses an engine and an electric motor (electric motor) as a power source.

Generally, a hydraulic excavator, which is a typical example of a work machine, includes an engine as a power source for traveling and working, and a hydraulic pump is driven by the engine. This hydraulic excavator performs excavation work of earth and sand by operating hydraulic actuators such as a hydraulic motor and a hydraulic cylinder by pressure oil supplied from a hydraulic pump.

By the way, the excavation work of earth and sand using a hydraulic excavator is not only a work that always requires the maximum output of the engine, but there are many work that can be covered with an output of about 80% of the maximum output of the engine, for example. For this reason, a hybrid hydraulic excavator has been proposed that includes an assist electric motor that assists the engine and a power storage device that stores electric power supplied to the assist electric motor while reducing the size of the engine.

This hybrid hydraulic excavator, when the output torque of the engine is larger than the driving torque of the hydraulic pump, drives the assist electric motor as a generator with the surplus torque and stores the generated power from the assist electric motor in the power storage device. On the other hand, when the output torque of the engine is smaller than the driving torque of the hydraulic pump, the assist electric motor is driven by the electric power supplied from the power storage device. Thus, the driving force of the hydraulic pump is assisted (assisted) by the driving force of the assist electric motor in addition to the driving force of the engine.

Furthermore, a hybrid work machine is proposed that includes a regenerative hydraulic motor that is rotated by return oil that returns from the hydraulic actuator of the work device to the hydraulic oil tank during excavation work, and a regenerative electric motor that is driven by this regenerative hydraulic motor. Has been.

In this hybrid work machine, the regenerative hydraulic motor is rotated by the return oil from the hydraulic actuator, and the regenerative electric motor is driven as a generator by the rotation of the regenerative hydraulic motor. Thereby, the electric power generated by the regenerative electric motor can be stored in the power storage device (see Patent Document 1).

JP 2004-169465 A

By the way, in the hybrid work machine according to the conventional technology described above, the regenerative hydraulic motor is attached to the power take-off device (PTO) provided in the engine, and the regenerative electric motor is separated from the regenerative hydraulic motor. It is configured to be attached to another power take-off device provided.

For this reason, the regenerative hydraulic motor and the regenerative electric motor are arranged at positions separated from each other via the engine, and workability when performing maintenance work on the regenerative hydraulic motor and the regenerative electric motor is reduced. There is a problem of end.

The present invention has been made in view of the above-described problems of the prior art, and can improve workability when performing maintenance work on a regenerative unit including a regenerative hydraulic motor and a regenerative electric motor. The purpose is to provide a hybrid work machine.

In order to solve the above-described problems, the present invention is provided with a self-propelled lower traveling body, an upper revolving body that is mounted on the lower traveling body and revolves by a revolving motor, and the upper revolving body is provided so as to be able to move up and down. The upper revolving structure comprises a revolving frame that forms a support structure, a prime mover that is installed horizontally on the revolving frame in a left and right direction, and a left and right one of the prime mover. And a hydraulic pump that discharges pressure oil toward the swing motor and the actuator of the work device by being driven by the prime mover, and is supplied to the swing motor and the actuator of the work device that is provided in the swing frame A hydraulic oil tank that stores the hydraulic oil to be stored, a power storage device that is provided in the swivel frame and stores power, and that rotates by the power from the power storage device and moves Assist electric motor for assisting driving of the hydraulic pump by the regenerative hydraulic motor rotating by return oil returning to the hydraulic oil tank from the swing motor or the actuator of the working device, and the power storage device driven by the regenerative hydraulic motor The present invention is applied to a hybrid work machine including a regenerative unit that includes a regenerative electric motor that generates stored electric power.

A feature of the present invention is that the hydraulic oil tank is located on the front side of the hydraulic pump and is provided in the revolving frame, and the regenerative hydraulic motor and the regenerative electric motor constituting the regenerative unit are located in the vicinity of the hydraulic oil tank. The configuration is to be positioned.

According to this configuration, the regenerative unit including the regenerative hydraulic motor and the regenerative electric motor can be collectively arranged in the vicinity of the hydraulic oil tank. Thereby, for example, compared with the case where the regenerative hydraulic motor and the regenerative electric motor are arranged at positions separated from each other, the maintenance work for the regenerative hydraulic motor and the maintenance work for the regenerative electric motor are performed in one common work place. Can be done from. As a result, workability when performing maintenance work on the regenerative unit can be improved. Further, by arranging the regenerative unit at a position close to the hydraulic oil tank, the oil path connecting the regenerative unit and the hydraulic oil tank can be shortened. As a result, the pressure loss of the return oil returning from the regenerative unit to the hydraulic oil tank can be reduced, and the regeneration efficiency can be increased.

1 is a front view showing a hydraulic excavator as a hybrid work machine according to a first embodiment of the present invention. It is the top view which looked at the upper turning body which removed the working apparatus from upper direction. It is a top view which shows the state which mounted the regeneration unit, engine, hydraulic pump, hydraulic oil tank, etc. by 1st Embodiment on the turning frame. It is the perspective view which looked at the state which opened the right front door and right rear door of the building cover from the right rear. 1 is a hydraulic circuit diagram including a regenerative hydraulic motor, a regenerative electric motor, a hydraulic pump, and the like according to a first embodiment. FIG. 6 is a plan view showing a state in which a regenerative unit, an engine, a hydraulic pump, a hydraulic oil tank, and the like are mounted on a swing frame in a hydraulic excavator as a hybrid work machine according to a second embodiment. FIG. 6 is a hydraulic circuit diagram including a regenerative hydraulic motor, a regenerative electric motor, a regenerative assist pump, and a hydraulic pump according to a second embodiment. It is a top view similar to FIG. 3 which shows the modification of arrangement | positioning of the regeneration unit by 1st Embodiment.

Hereinafter, embodiments of the construction machine according to the present invention will be described in detail with reference to the accompanying drawings, taking as an example a case where the construction machine is applied to a hydraulic excavator. 1 to 5 show a hydraulic excavator according to a first embodiment of the present invention.

In the drawing, a hydraulic excavator 1 is a hybrid work machine. The hydraulic excavator 1 is mounted on a crawler type lower traveling body 2 capable of self-propelling and capable of turning on the lower traveling body 2 via a swirling wheel 3. The upper revolving body 4 and the working device 5 provided on the front side of the upper revolving body 4 so as to be able to move up and down are configured.

The working device 5 performs excavation work of earth and sand. The working device 5 is attached to a swing frame 6 to be described later so as to be able to move up and down, and is attached to the tip side of the boom 5A so as to be rotatable. An arm (not shown), a bucket (not shown) rotatably attached to the tip side of the arm, and an actuator including a boom cylinder 5B, an arm cylinder, and a bucket cylinder (all not shown) It is comprised by.

The turning frame 6 is a base of the upper turning body 4. As shown in FIG. 3, the swivel frame 6 is formed in a thick flat plate shape and extends in the front and rear directions, and the front and rear sides of the swivel frame 6 standing on the bottom plate 6A and facing left and right. Left vertical plate 6B and right vertical plate 6C extending in the direction, a plurality of left extending beams 6D extending from the left vertical plate 6B to the left, and a plurality extending from the right vertical plate 6C to the right. Right extending beam 6E, a left side frame 6F which is fixed to the front end side of each left extending beam 6D and extending rearward, and a right side which is fixed to the front end side of each right extending beam 6E and extends rightward and rearward. The side frame 6G is included.

The base end part (foot part) of the boom 5A is rotatably connected to the front end side of the left and right

vertical plates

6B and 6C constituting the revolving frame 6. A cab 7 that defines a cab is provided on the left side of the front portion of the revolving frame 6. On the other hand, a counterweight 8 is provided on the rear end side of the revolving frame 6 to balance the weight with the work device 5.

The engine 9 as a prime mover is positioned on the front side of the counterweight 8 and is disposed on the rear side of the turning frame 6. The engine 9 is disposed on the revolving frame 6 in a horizontal state in which an axis of a crankshaft (not shown) extends leftward and rightward. A hydraulic pump 14 and an assist electric motor 15, which will be described later, are attached to the right side of the engine 9. The hydraulic pump 14 and the assist electric motor 15 are driven by the engine 9.

The heat exchange device 10 is mounted on the revolving frame 6 on the left side of the engine 9. The heat exchanging device 10 is formed as one unit including a radiator 11 that cools engine coolant and an oil cooler 12 that cools hydraulic oil. The heat exchange device 10 cools engine cooling water, hydraulic oil, and the like by supplying cooling air from a cooling fan 9 A attached to the engine 9 to the radiator 11 and the oil cooler 12.

The power storage device 13 is mounted on the turning frame 6 so as to be positioned on the front side of the heat exchange device 10. The power storage device 13 stores power for assist supplied to an assist electric motor 15 described later. The power storage device 13 is composed of, for example, a lithium ion battery, and charges and discharges power with the assist electric motor 15.

The hydraulic pump 14 is attached to the right side of the engine 9 with the assist electric motor 15 interposed therebetween. The hydraulic pump 14 is driven by the engine 9 to supply operating hydraulic oil to various hydraulic actuators mounted on the excavator 1.

The assist electric motor 15 is attached to the output side of the engine 9 together with the hydraulic pump 14. The assist electric motor 15 is disposed between the engine 9 and the hydraulic pump 14, and the motor shaft of the assist electric motor 15 is connected to the output shaft of the engine 9 and the input shaft of the hydraulic pump 14. Here, as shown in FIG. 5, the assist electric motor 15 is electrically connected to the inverter 16, and the inverter 16 is electrically connected to the power storage device 13.

The assist electric motor 15 generates electric power by being driven by the engine 9, and the AC power generated by the assist electric motor 15 is stored in the power storage device 13 in a state converted into DC power by the inverter 16. On the other hand, the assist electric motor 15 is driven by the electric power from the power storage device 13 to assist the driving of the hydraulic pump 14 by the engine 9.

Here, the inverter 16 is configured by using a plurality of switching elements, and by controlling on / off of the switching elements, the AC power from the assist electric motor 15 is converted into DC power when the assist electric motor 15 generates power. And supplied to the power storage device 13. On the other hand, when assisting the drive of the hydraulic pump 14 by the assist electric motor 15, the inverter 16 generates three-phase AC power from the DC power of the power storage device 13 and supplies the three-phase AC power to the assist electric motor 15.

The partition member 17 is erected on the revolving frame 6 with the front side of the engine 9 extending leftward and rightward. The partition member 17 is located between the intermediate partition plate 17 A disposed on the front side of the engine 9 and the assist electric motor 15, the heat exchange device 10 and the power storage device 13, and the left disposed on the front side of the heat exchange device 10. The partition plate 17 B and the right partition plate 17 C disposed on the front side of the hydraulic pump 14 are configured.

The intermediate partition plate 17A prevents heat and noise generated from the engine 9 from leaking from the front side of the engine 9 to the outside. The left partition plate 17B suppresses the heat generated from the heat exchange device 10 from being transmitted to the power storage device 13, and the right partition plate 17C suppresses the heat generated from the hydraulic pump 14 from being transmitted to the hydraulic oil tank 20 described later. It is.

The control valve 18 is disposed on the front side of the partition member 17. The control valve 18 is disposed on the opposite side (front side) from the engine 9 with the intermediate partition plate 17A interposed therebetween. That is, the control valve 18 is provided on the bottom plate 6A of the revolving frame 6 between the left vertical plate 6B and the right vertical plate 6C. The control valve 18 is a collection of a number of directional control valves including a turning directional control valve 36 and a boom directional control valve 55 which will be described later, and pressure oil supplied to various hydraulic actuators mounted on the hydraulic excavator 1. It controls the flow direction.

The turning motor 19 is disposed on the front side of the control valve 18. The turning motor 19 is provided on the bottom plate 6A of the turning frame 6 so as to be positioned between the left and right

vertical plates

6B and 6C. The turning motor 19 is constituted by a hydraulic motor, and the upper turning body 4 is turned on the lower traveling body 2 by being supplied with pressure oil from the hydraulic pump 14. Here, a swing regenerative valve 40 described later is integrally attached to the swing motor 19. A boom regenerative valve 59 described later is provided on the bottom plate 6A of the turning frame 6 on the front side of the turning motor 19 so as to be positioned between the

vertical plates

6B and 6C.

The hydraulic oil tank 20 is disposed on the front side of the hydraulic pump 14 with the partition member 17 interposed therebetween. The hydraulic oil tank 20 stores hydraulic oil supplied to a hydraulic actuator mounted on the hydraulic excavator 1. Here, the hydraulic oil tank 20 is formed as a hollow box having a rectangular parallelepiped shape as a whole, and is disposed between the right vertical plate 6C and the right side frame 6G of the revolving frame 6.

Further, as shown in FIG. 4, a regenerative unit accommodation space 21 for accommodating a regenerative unit 25 described later is formed between the rear surface 20A of the hydraulic oil tank 20 and the right partition plate 17C. On the other hand, a fuel tank 22 that stores fuel supplied to the engine 9 is provided on the front side of the hydraulic oil tank 20.

Next, the regenerative hydraulic motor 23 and the regenerative electric motor 24 used in the present embodiment will be described.

The regenerative hydraulic motor 23 is provided adjacent to the vicinity (rear side) of the hydraulic oil tank 20 at a position spaced forward from the hydraulic pump 14. The regenerative hydraulic motor 23 is mounted on the right overhanging beam 6E of the revolving frame 6 with a motor shaft (not shown) horizontally placed extending leftward and rightward. Here, the regenerative hydraulic motor 23 is rotated by return oil from the turning motor 19 or the boom cylinder 5B.

The regenerative electric motor 24 is provided adjacent to the vicinity of the hydraulic oil tank 20 at a position separated from the hydraulic pump 14 together with the regenerative hydraulic motor 23. The regenerative electric motor 24 is mounted on the right extending beam 6E of the swivel frame 6 in a horizontal state in which a motor shaft (not shown) extends leftward and rightward.

Here, the motor shaft of the regenerative electric motor 24 is connected to the motor shaft of the regenerative hydraulic motor 23 via a power transmission mechanism (not shown). Thus, the regenerative hydraulic motor 23 and the regenerative electric motor 24 constitute a regenerative unit 25 separated from the engine 9. The regenerative hydraulic motor 23 and the regenerative electric motor 24 are provided between the hydraulic pump 14 and the hydraulic oil tank 20, more specifically, the right partition plate 17C of the partition member 17 provided on the front side of the hydraulic pump 14 and the hydraulic oil tank. 20 are accommodated side by side in the left and right directions in a regenerative unit accommodation space 21 formed between them.

On the other hand, as shown in FIG. 5, the regenerative electric motor 24 is electrically connected to the inverter 26, and the inverter 26 is electrically connected to the power storage device 13. The regenerative electric motor 24 generates power by being driven by the regenerative hydraulic motor 23. The AC power generated by the regenerative electric motor 24 is converted into DC power by the inverter 26 and stored in the power storage device 13.

The regenerative hydraulic motor 23 and the regenerative electric motor 24 that constitute the regenerative unit 25 are separated from the hydraulic pump 14 to the front side, and are disposed adjacent to the left and right directions at positions near the hydraulic oil tank 20. . Accordingly, the regenerative hydraulic motor 23 and the regenerative electric motor 24 are collectively arranged at a position separated from the engine 9. Therefore, the maintenance work for the regenerative hydraulic motor 23 and the maintenance work for the regenerative electric motor 24 can be performed from a common work place.

The building cover 27 is located on the front side of the counterweight 8 and is provided on the revolving frame 6. The building cover 27 accommodates onboard equipment including the engine 9, the power storage device 13, the hydraulic pump 14, the assist electric motor 15, the regenerative hydraulic motor 23, and the regenerative electric motor 24. The building cover 27 includes a left side cover 28, an upper surface cover 29, an engine cover 30, and a right side door 31, which will be described later.

The left side cover 28 constitutes the left side of the building cover 27, and the left side cover 28 is provided between the left end of the counterweight 8 and the cab 7. Here, the left side cover 28 rises upward from the left side frame 6F and extends forward and rearward along the left side frame 6F. Thereby, the left side cover 28 covers the heat exchange device 10, the power storage device 13 and the like so that they can be opened and closed from the left side.

The upper surface cover 29 constitutes the upper surface of the building cover 27, and the upper surface cover 29 extends leftward and rightward between an upper end portion of the left side cover 28 and an upper end portion of a right side door 31 described later. ing. The upper surface cover 29 covers mounted devices including the engine 9 and the heat exchange device 10 from above. An opening (not shown) for work is formed in the upper surface cover 29, and this opening is covered with an engine cover 30 so as to be openable and closable. Therefore, when performing maintenance work on the engine 9 and the heat exchange device 10, the operator can open the engine cover 30 and access the building cover 27 through the work opening.

The right side door 31 constitutes the right side of the building cover 27, and the right side door 31 is provided between the right end of the counterweight 8 and the fuel tank 22. Here, the right side door 31 is located on the counterweight 8 side and covers the right rear side door 31A that covers the hydraulic pump 14 and the like from the right side, and the regenerative hydraulic motor 23 and the regenerative electric motor 24 located on the fuel tank 22 side on the right side. It is comprised by the right front side door 31B covered from the direction.

The rear end portion of the right rear side door 31A is rotatably supported by a support member provided on the revolving frame 6 via a hinge mechanism (both not shown). On the other hand, the front end portion of the right front side door 31B is rotatably supported on the rear surface of the fuel tank 22 via a hinge mechanism (not shown), for example.

Therefore, by opening the right rear side door 31A and the right front side door 31B, the regenerative unit accommodation space 21 can be opened to the outside. The regenerative hydraulic motor 23 and the regenerative electric motor accommodated in the regenerative unit accommodation space 21 are provided. The workability at the time of performing the maintenance work for 24 can be improved.

Next, a hydraulic circuit including the regenerative hydraulic motor 23 and the regenerative electric motor 24 according to the present embodiment will be described with reference to FIG.

The hydraulic pump 14 provided in the upper swing body 4 constitutes a hydraulic pressure source together with the hydraulic oil tank 20, and supplies the hydraulic oil in the hydraulic oil tank 20 to the delivery line 14A as high pressure oil. The pressure oil supplied from the hydraulic pump 14 to the delivery pipeline 14A is supplied to the swing motor 19 and the boom cylinder 5B through a swing direction control valve 36 and a boom direction control valve 55, which will be described later, constituting the control valve 18. The The control valve 18 representatively shows two directional control valves, a turning directional control valve 36 and a boom directional control valve 55. The control valve 18 includes an arm directional control valve and a bucket. A directional control valve or the like is also included.

In the control valve 18, there is provided a center bypass line 32 that connects between the delivery line 14A and the return line 32A (the hydraulic oil tank 20). In the center bypass pipe 32, a turning direction control valve 36 and a boom direction control valve 55 are provided in parallel connection. On the upstream side of the turning direction control valve 36, a branch pipe 33 A branching from the center bypass pipe 32 is provided, and the branch pipe 33 A is connected to the high-pressure side port of the turning direction control valve 36. Another branch conduit 33B is provided on the upstream side of the boom direction control valve 55, and the branch conduit 33B is connected to the high-pressure side port of the boom direction control valve 55. Between the turning direction control valve 36 and the return line 32A, a tank line 34A for returning the return oil from the turning motor 19 to the hydraulic oil tank 20 is provided. Between the boom direction control valve 55 and the return line 32A, a tank line 34B for circulating the return oil from the boom cylinder 5B to the hydraulic oil tank 20 is provided.

Between the turning motor 19 and the turning direction control valve 36, a pair of

main pipes

35A and 35B for supplying and discharging pressure oil to the turning motor 19 are connected. Each of the

main pipelines

35A and 35B is connected to the branch pipeline 33A or the tank pipeline 34A according to the switching position of the turning direction control valve 36.

The turning direction control valve 36 is connected to the center bypass conduit 32. The turning direction control valve 36 is one of many direction control valves constituting the control valve 18. The turning direction control valve 36 is a 6-port 3-position direction control valve having

pilot portions

36A and 36B. Pilot pressures are supplied to the

pilot portions

36A and 36B of the turning direction control valve 36 through pilot pipelines 36A1 and 36B1 in accordance with the operation of an operation lever (not shown) of a hydraulic pilot valve disposed in the cab 7. Is done. As a result, the turning direction control valve 36 has a neutral position (A) for stopping the supply and discharge of the pressure oil to the turning motor 19, and a switching position (B) for supplying and discharging the pressure oil to the turning motor 19. (C).

A pair of make-up

check valves

37A and 37B are connected in the middle of the

main pipelines

35A and 35B. When each of the

check valves

37A and 37B has a negative pressure in the

main pipeline

35A or 35B due to the inertial rotation of the swing motor 19, the hydraulic oil in the hydraulic oil tank 20 is fed into the

main pipelines

35A and 35B through the tank pipeline 38. Replenish.

The pair of

relief valves

39A and 39B are connected in the middle of the

main pipelines

35A and 35B. Each

relief valve

39A, 39B has a function of relieving this excessive pressure and protecting the hydraulic equipment when an excessive pressure is generated in one main conduit 35A (35B) by the inertial rotation of the swing motor 19. Yes.

The turning regenerative valve 40 is located between the turning motor 19 and the turning direction control valve 36 and is provided in the middle of the

main pipelines

35A and 35B. The swing regenerative valve 40 supplies pressure oil (return oil from the swing motor 19) discharged by the pump action of the swing motor 19 to the regenerative hydraulic motor 23 when the swing motor 19 performs inertial rotation. . The swivel regenerative valve 40 includes

check valves

42A and 42B, which will be described later, a swivel regenerative main switching valve 45, a swivel regenerative pilot valve 49, and an electromagnetic pilot valve 51.

The connection pipeline 41 is connected to the main pipeline 35A and the main pipeline 35B. A pair of check valves 42 A and 42 B are connected in the middle of the connection pipe 41. These

check valves

42A and 42B allow the flow of pressure oil from the

main pipelines

35A and 35B toward the connection pipeline 41, and prevent the reverse flow. One end side of the swivel regeneration conduit 43 is connected to the connection portion 43A in the middle of the connection conduit 41 located between the

check valves

42A and 42B. The other end side of the turning regeneration pipeline 43 is connected to a boom regeneration pipeline 68 described later. A check valve 44 is connected in the middle of the swivel regenerative pipe 43, and this check valve 44 allows the flow of pressure oil toward the regenerative hydraulic motor 23 and prevents the reverse flow.

The turning regeneration main switching valve 45 is provided in the middle of the turning regeneration pipeline 43. This turning regeneration main switching valve 45 is connected between a check valve 44 and a connection portion 43 A between the connection pipe 41 and the turning regeneration pipe 43. Here, the swivel regeneration main switching valve 45 is a two-port, two-position switching valve, and normally maintains the shut-off position (A) to shut off the swivel regeneration conduit 43. On the other hand, the turning regeneration main switching valve 45 is switched to the communication position (B) when the pilot pressure is supplied to the pilot section 45 A, and makes the turning regeneration pipeline 43 communicate. The pilot portion 45 A of the turning regeneration main switching valve 45 and the turning regeneration pipeline 43 are connected via a pilot pipeline 46. A one-way throttle valve 47 composed of a check valve and a throttle is provided in the middle of the pilot line 46.

The bypass pipe line 48 connects the connection pipe line 41 and the swivel regeneration pipe line 43. One end of the bypass conduit 48 is connected to the connection conduit 41 at the connection portion 48A. On the other hand, the other end side of the bypass pipe 48 is connected to the turning regeneration pipe 43 between the check valve 44 and the turning regeneration main switching valve 45.

The turning regeneration pilot valve 49 is connected in the middle of the bypass line 48. The regenerative pilot valve 49 is composed of a 2-port 2-position switching valve, and normally maintains the shut-off position (A) and shuts off the bypass line 48. On the other hand, the swivel regeneration pilot valve 49 is switched to the communication position (B) when the pilot pressure is supplied to the pilot section 49A, and communicates the bypass pipe line 48 via the throttle 49B.

The bypass pipe 48 and the pilot portion 49A of the swivel regenerative pilot valve 49 are connected via a pilot pipe 50. An electromagnetic pilot valve 51 at a 3-port 2-position is connected in the middle of the pilot pipe line 50. The electromagnetic pilot valve 51 always maintains the shut-off position (A), thereby shutting off the pilot conduit 50 and connecting the pilot portion 49A of the revolving regenerative pilot valve 49 to the hydraulic oil tank 20. A regenerative valve pilot conduit 52 is connected to the pilot portion 51 A of the electromagnetic pilot valve 51. The electromagnetic pilot valve 51 is switched to the communication position (B) by supplying pilot pressure through the regenerative valve pilot line 52 in accordance with a control signal from a controller (not shown), and the pilot line 50 is Communicate.

The pilot pressure supplied to the

pilot portions

36A and 36B of the turning direction control valve 36 is detected by the

pressure sensors

53A and 53B. The pressure in the

main pipelines

35A and 35B is detected by

pressure sensors

53C and 53D. A controller (not shown) controls the electromagnetic pilot valve 51 of the swivel regenerative valve 40 based on detection signals from the

pressure sensors

53A, 53B, 53C, 53D and a pressure sensor 76C described later.

On the other hand, a pair of

main pipelines

54A and 54B are connected between a boom cylinder 5B constituting the working device 5 and a boom direction control valve 55 described later. These

main pipelines

54A and 54B supply and discharge pressure oil to and from the bottom side oil chamber 5B1 and the rod side oil chamber 5B2 of the boom cylinder 5B. The

main pipelines

54A and 54B are connected to the branch pipeline 33B or the tank pipeline 34B according to the switching position of the boom direction control valve 55.

The boom direction control valve 55 is connected to the center bypass pipe 32 on the downstream side of the turning direction control valve 36. The boom directional control valve 55 is also one of many directional control valves constituting the control valve 18. The boom direction control valve 55 is a 6-port 3-position direction control valve having

pilot portions

55A and 55B. A pilot pressure is applied to

pilot portions

55A and 55B of the boom direction control valve 55 through

pilot pipelines

74 and 75, which will be described later, in response to an operation of an operation lever (not shown) of a hydraulic pilot valve disposed in the cab 7. Supplied. As a result, the boom direction control valve 55 has a neutral position (A) for stopping supply and discharge of pressure oil to the boom cylinder 5B, and a switching position (B) for supplying and discharging pressure oil to and from the boom cylinder 5B. (C).

A pair of make-up

check valves

56A and 56B are provided between the

main pipelines

54A and 54B and the return pipeline 32A, respectively. Each

check valve

56A, 56B replenishes the hydraulic oil in the hydraulic oil tank 20 into the

main pipelines

54A, 54B through the return pipeline 32A when the pressure in the

main pipeline

54A or 54B becomes negative.

The pair of

relief valves

57A and 57B are provided between the

main pipelines

54A and 54B and the return pipeline 32A, respectively. Each

relief valve

57A, 57B has a function of relieving the excessive pressure when the excessive pressure is generated in the

main pipelines

54A, 54B and protecting the hydraulic equipment.

The pilot operated check valve 58 is provided in the middle of the main pipeline 54A. The check valve 58 is connected to a later-described check valve pilot pipe 74B. The check valve 58 prevents the flow of pressure oil from the boom cylinder 5B toward the boom direction control valve 55 when the pilot pressure is not supplied through the check valve pilot pipe line 74B. On the other hand, the check valve 58 allows the flow of pressure oil from the boom cylinder 5B toward the boom direction control valve 55 when the pilot pressure is supplied through the check valve pilot line 74B.

The boom regenerative valve 59 is provided in the middle of the

main pipelines

54A and 54B. The boom regenerative valve 59 supplies pressure oil (return oil from the boom cylinder 5B) discharged from the bottom side oil chamber 5B1 of the boom cylinder 5B when the boom cylinder 5B is contracted and the boom 5A is rotated downward. The regenerative hydraulic motor 23 is supplied. Here, the boom regenerative valve 59 includes a pipe switching valve 60, a control valve return valve 61, a communication valve 64, a residual pressure adjusting valve 67, and a regenerative switching valve 70 which will be described later.

The pipeline switching valve 60 is provided in the middle of the main pipeline 54B. This pipeline switching valve 60 is a three-port 2-position switching valve having a pilot portion 60A, and is connected to the main pipeline 54B and the return pipeline 32A. The pilot section 60A of the pipe switching valve 60 is connected to a switching valve pilot pipe 74G described later. The pipeline switching valve 60 always maintains a communication position (A) that allows the main pipeline 54B to communicate. On the other hand, the pipeline switching valve 60 is switched to the switching position (B) when the pilot pressure is supplied to the pilot section 60A through the switching valve pilot pipeline 74G, and connects the main pipeline 54B to the return pipeline 32A. It is.

The control valve return valve 61 is provided in the middle of the main pipeline 54A. The control valve return valve 61 is a 3-port 2-position switching valve having a pilot portion 61A. The control valve return valve 61 is connected in the middle of the main pipeline 54A, and is connected at one end to the other end of the connection pipeline 62 connected to the main pipeline 54B. The pilot portion 61A of the control valve return valve 61 is connected to a return valve pilot pipe 74C described later. The control valve return valve 61 always maintains the communication position (A), allows the main pipeline 54A to communicate, and part of the pressure oil flowing through the main pipeline 54A to the connection pipeline 62 via the check valve 61B. Lead. On the other hand, the control valve return valve 61 is switched to the throttle position (B) when the pilot pressure is supplied to the pilot section 61A through the return valve pilot pipe 74C, and communicates with the main pipe 54A via the throttle 61C.

The communication pipeline 63 is provided by connecting the

main pipelines

54A and 54B. In this case, the communication pipeline 63 connects the

main pipelines

54A and 54B closer to the boom cylinder 5B than the pipeline switching valve 60 and the control valve return valve 61. The communication valve 64 is provided in the middle of the communication pipe 63. The communication valve 64 is a two-port 2-position switching valve having a pilot portion 64A, and the pilot portion 64A of the communication valve 64 is connected to a communication valve pilot pipe 74D described later. The communication valve 64 always maintains the blocking position (A) and blocks the communication pipe 63. On the other hand, the communication valve 64 is switched to the communication position (B) when the pilot pressure is supplied to the pilot section 64A through the communication valve pilot pipe 74D, and the communication pipe 63 is communicated. A check valve 65 is provided in the middle of the communication pipe 63, and this check valve 65 allows the flow of pressure oil from the main pipe 54 A to the main pipe 54 B via the communication valve 64, and prevents the reverse flow. To do.

One end of the tank conduit 66 is connected to the main conduit 54B between the conduit switching valve 60 and the boom cylinder 5B, and the other end of the tank conduit 66 is connected to the return conduit 32A. A residual pressure adjusting valve 67 is connected in the middle of the tank conduit 66. The residual pressure adjusting valve 67 is a two-port 2-position switching valve having a pilot portion 67A, and the pilot portion 67A of the residual pressure adjusting valve 67 is connected to an after-mentioned adjusting valve pilot conduit 74E. The residual pressure adjusting valve 67 normally maintains the shut-off position (A) and shuts off the tank conduit 66. On the other hand, the residual pressure adjusting valve 67 is switched to the communication position (B) when the pilot pressure is supplied to the pilot portion 67A through the adjusting valve pilot pipe 74E, and the tank pipe 66 is connected.

The boom regenerative pipe 68 has one end connected to the main pipe 54A between the control valve return valve 61 and the boom cylinder 5B, and the other end connected to the regenerative hydraulic motor 23. The regenerative hydraulic motor 23 and the hydraulic oil tank 20 are connected via a tank line 69. A regeneration switching valve 70 is connected in the middle of the boom regeneration pipe 68. The regenerative switching valve 70 is a 2-port 2-position switching valve having a pilot portion 70A, and the pilot portion 70A of the regenerative switching valve 70 is connected to a regenerative valve pilot conduit 74F described later. The regenerative switching valve 70 normally maintains the shut-off position (A) and shuts off the boom regenerative pipe 68. On the other hand, the regenerative switching valve 70 is switched to the communication position (B) when the pilot pressure is supplied to the pilot portion 70A through the regenerative valve pilot line 74F, and the boom regenerative line 68 is communicated via the throttle 70B. Is.

A check valve 71 is provided in the middle of the boom regenerative pipe 68, and this check valve 71 is provided between the regenerative switching valve 70 and the regenerative hydraulic motor 23. The check valve 71 allows the flow of pressure oil from the regenerative switching valve 70 toward the regenerative hydraulic motor 23 and prevents the reverse flow. The bypass line 72 bypasses the control valve return valve 61 and connects between the main line 54A and the boom regenerative line 68. A check valve 73 is provided in the middle of the bypass line 72. The check valve 73 allows the flow of pressure oil from the main pipeline 54A toward the boom regeneration pipeline 68 and prevents the reverse flow.

The

pilot pipelines

74 and 75 are connected to the

pilot portions

55A and 55B of the boom direction control valve 55, respectively. These

pilot conduits

74 and 75 supply pilot pressure to the

pilot portions

55A and 55B of the boom direction control valve 55 in accordance with the operation of an operation lever (not shown) disposed in the cab 7. .

Here, the pilot pipe line 74 includes a directional control valve pilot pipe line 74A connected to the pilot section 55A of the boom directional control valve 55, a check valve pilot pipe line 74B connected to the check valve 58, and a control. A return valve pilot line 74C connected to the pilot part 61A of the valve return valve 61, a communication valve pilot line 74D connected to the pilot part 64A of the communication valve 64, and a pilot part 67A of the residual pressure adjusting valve 67. For control valve connected to the pilot part 60A of the regenerative valve 60A, the pilot line 74F for regenerative valve connected to the pilot part 70A of the regenerative switching valve 70, and the pilot part 60A of the regenerative switching valve 70 Branches to the pilot line 74G. When pilot pressure is supplied to the pilot portion 55A of the boom direction control valve 55 through the direction control valve pilot line 74A, this pilot pressure is supplied to the check valve 58. On the other hand, the control valve return valve 61, the communication valve 64, the residual pressure adjusting valve 67, the regenerative switching valve 70, and the

pilot sections

61A, 64A, 67A, 70A, 60A of the pipe switching valve 60 are respectively supplied with control signals from the controller. Accordingly, pilot pressure is supplied.

The pressure of the pilot pressure supplied to the pilot section 55A of the boom direction control valve 55 is detected by the pressure sensor 74H. The pressures in the

main pipelines

54A and 54B are detected by

pressure sensors

76A and 76B. Further, the pressure on the inflow side of the regenerative hydraulic motor 23 is detected by the pressure sensor 76C. Based on detection signals from these

pressure sensors

74H, 76A, 76B, and 76C, a controller (not shown) controls the pipe switching valve 60, the control valve return valve 61, the communication valve 64, the remaining valve, and the like that constitute the boom regenerative valve 59. The pressure regulating valve 67 and the regeneration switching valve 70 are controlled.

The hybrid excavator 1 according to the present embodiment has the above-described configuration, and the operation thereof will be described next.

When the engine 9 of the hydraulic excavator 1 is operated, the hydraulic pump 14 and the assist electric motor 15 are driven by the engine 9. The hydraulic pump 14 sucks and pressurizes the hydraulic oil in the hydraulic oil tank 20 and discharges it toward various hydraulic actuators. As a result, the excavator 1 performs a traveling operation by the lower traveling body 2, a turning operation by the upper revolving body 4, excavation work by the work device 5, and the like.

In this case, when the output torque of the engine 9 is larger than the driving torque of the hydraulic pump 14, the assist electric motor 15 is driven as a generator by the surplus torque. Thereby, the assist electric motor 15 generates AC power, and this AC power is converted into DC power by the inverter 16 and stored in the power storage device 13.

On the other hand, when the output torque of the engine 9 is smaller than the driving torque of the hydraulic pump 14, the assist electric motor 15 is driven as an electric motor by the electric power from the power storage device 13. Accordingly, the assist electric motor 15 can assist (assist) the engine 9 to drive the hydraulic pump 14.

Here, in the hydraulic excavator 1 according to the present embodiment, the regenerative hydraulic motor 23 uses the return oil that returns from the swing motor 19 to the hydraulic oil tank 20 when the upper swing body 4 rotates inertially on the lower traveling body 2. Rotating regenerative operation to drive is performed. Further, the hydraulic excavator 1 drives the regenerative hydraulic motor 23 using the return oil that returns from the bottom side oil chamber 5B1 of the boom cylinder 5B to the hydraulic oil tank 20 when the boom 5A of the working device 5 rotates downward. Perform boom regeneration operation.

Therefore, a turning regenerative operation for driving the regenerative hydraulic motor 23 using the return oil from the turning motor 19 during the inertia rotation of the upper turning body 4 will be described.

In a state where the upper swing body 4 performs a swing operation on the lower traveling body 2, when the turning direction control valve 36 is switched from the switching position (B) or (C) to the neutral position (A), the upper swing body 4 is moved. Inertia rotation is performed on the lower traveling body 2. Thereby, the turning motor 19 performs a pump action by inertia rotation, and the turning motor 19 discharges the pressure oil to one of the

main pipelines

35A and 35B. The pressure oil flows into the connection pipe 41 through the check valve 42A or the check valve 42B.

At this time, pilot pressure is supplied to the pilot portion 51A of the electromagnetic pilot valve 51 in accordance with a control signal from a controller (not shown), and the electromagnetic pilot valve 51 is switched to the communication position (B). As a result, the pressure oil that has flowed into the connection pipe 41 is supplied to the pilot portion 49 A of the turning regeneration pilot valve 49 through the pilot pipe 50. Accordingly, the swivel regenerative pilot valve 49 is switched to the communication position (B), and the pressure oil in the connection pipe 41 passes through the throttle 49B of the swivel regenerative pilot valve 49, and the bypass line 48, the pilot line 46, The directional throttle valve 47 is supplied to the pilot section 45A of the turning regeneration main switching valve 45.

As a result, the turning regeneration main switching valve 45 is switched to the communication position (B), and the pressure oil that has flowed into the connection pipe 41 is supplied to the regeneration hydraulic motor 23 through the turning regeneration pipe 43, the boom regeneration pipe 68, and the like. Is done. As a result, the regenerative hydraulic motor 23 can be rotated using the return oil from the turning motor 19, and the regenerative electric motor 24 can be driven by the regenerative hydraulic motor 23. AC power generated by the regenerative electric motor 24 is converted into DC power by the inverter 26 and stored in the power storage device 13.

Next, the operation of the boom cylinder 5B when the boom 5A of the work device 5 is turned upward will be described.

When the boom cylinder 5B is extended to rotate the boom 5A upward, the pilot portion 55B of the boom direction control valve 55 is operated in accordance with an operation of an operation lever (not shown) disposed in the cab 7. The pilot pressure is supplied to the boom, and the boom direction control valve 55 is switched to the switching position (C).

Thereby, the pressure oil from the hydraulic pump 14 is supplied to the bottom side oil chamber 5B1 of the boom cylinder 5B through the boom direction control valve 55, the main pipeline 54A, the bypass pipeline 72, and the like. On the other hand, the pressure oil in the rod side oil chamber 5B2 of the boom cylinder 5B circulates to the hydraulic oil tank 20 through the main pipeline 54B, the pipeline switching valve 60, the boom direction control valve 55, the return pipeline 32A, and the like. As a result, the boom cylinder 5B extends, and the boom 5A rotates upward.

Next, the operation of the boom cylinder 5B when the boom 5A is rotated downward will be described.

When the boom cylinder 5B is contracted to rotate the boom 5A downward, the pilot pressure is supplied to the pilot portion 55A of the boom direction control valve 55 according to the operation of the operation lever arranged in the cab 7. The boom direction control valve 55 is switched to the switching position (B). At this time, the pilot pressure is supplied to the check valve 58 through the check valve pilot pipe 74B, so that the pilot operated check valve 58 is opened. On the other hand, pilot pressure is supplied to the pilot section 60A of the pipeline switching valve 60 in accordance with a control signal from a controller (not shown), and the pipeline switching valve 60 is switched to the switching position (B).

Thus, the pressure oil supplied from the hydraulic pump 14 is returned to the hydraulic oil tank 20 through the boom direction control valve 55, the pipe switching valve 60, and the return pipe 32A without being supplied to the boom cylinder 5B.

In this state, when the boom cylinder 5B is reduced by its own weight, the pressure oil in the bottom side oil chamber 5B1 is discharged to the main conduit 54A. The discharged pressure oil passes through the control valve return valve 61 from the main pipeline 54A, and then is divided into a flow toward the rod side oil chamber 5B2 of the boom cylinder 5B and a flow toward the hydraulic oil tank 20.

That is, the pressure oil that has passed through the check valve 61B of the control valve return valve 61 is guided to the main pipeline 54B through the connection pipeline 62, and flows into the rod-side oil chamber 5B2 of the boom cylinder 5B through the main pipeline 54B. On the other hand, the pressure oil guided to the main line 54A through the control valve return valve 61 is returned to the hydraulic oil tank 20 through the check valve 58, the boom direction control valve 55, the tank line 34B, the return line 32A, and the like. . As a result, the boom cylinder 5B is reduced, and the return oil from the boom cylinder 5B (bottom side oil chamber 5B1) flows back to the hydraulic oil tank 20 without being supplied to the regenerative hydraulic motor 23.

Next, a boom regenerative operation for driving the regenerative hydraulic motor 23 using the return oil from the bottom side oil chamber 5B1 of the boom cylinder 5B when the boom 5A rotates downward will be described.

When the boom regeneration operation is performed using the return oil from the bottom side oil chamber 5B1 of the boom cylinder 5B, the pilot portion of the boom direction control valve 55 is operated according to the operation of the operation lever arranged in the cab 7. The pilot pressure is supplied to 55A, and the boom direction control valve 55 is switched to the switching position (B). At this time, the pilot pressure is supplied to the check valve 58 through the check valve pilot pipe 74B, so that the pilot operated check valve 58 is opened. On the other hand, pilot pressure is supplied to the pilot section 60A of the pipeline switching valve 60 in accordance with a control signal from a controller (not shown), and the pipeline switching valve 60 is switched to the switching position (B).

Meanwhile, pilot pressure is supplied to the control valve return valve 61, the communication valve 64, and the

pilot portions

61A, 64A, and 70A of the regenerative switching valve 70 according to control signals from a controller (not shown). As a result, the control valve return valve 61 is switched to the throttle position (B), the communication valve 64 is switched to the communication position (B), and the regeneration switching valve 70 is switched to the communication position (B).

In this state, when the boom cylinder 5B is reduced by its own weight, the pressure oil in the bottom side oil chamber 5B1 is discharged to the main conduit 54A. The discharged pressure oil is divided into a flow toward the rod side oil chamber 5B2 of the boom cylinder 5B through the communication conduit 63 and a flow toward the regenerative hydraulic motor 23 through the boom regeneration conduit 68.

That is, the pressure oil guided from the main pipe line 54A to the communication pipe line 63 flows into the rod side oil chamber 5B2 of the boom cylinder 5B through the communication valve 64 and the main pipe line 54B, and the pressure in the bottom side oil chamber 5B1 increases. On the other hand, the pressure oil led from the main pipeline 54 A to the boom regeneration pipeline 68 is supplied to the regeneration hydraulic motor 23 through the regeneration switching valve 70, the check valve 71, and the boom regeneration pipeline 68. As a result, the boom cylinder 5B is reduced, and at the same time, the regenerative hydraulic motor 23 is rotated using the return oil from the boom cylinder 5B, and the regenerative electric motor 24 can be driven by the regenerative hydraulic motor 23. AC power generated by the regenerative electric motor 24 is converted into DC power by the inverter 26 and stored in the power storage device 13.

A part of the pressure oil led from the main pipeline 54A to the boom regeneration pipeline 68 passes through the control valve return valve 61, the main pipeline 54A, the check valve 58, the boom direction control valve 55, the tank pipeline 34B, and the return pipeline 32A. Returned to the hydraulic oil tank 20. After the boom regeneration operation described above is completed, the pilot pressure is supplied to the pilot portion 67A of the residual pressure adjustment valve 67 according to the control signal from the controller. As a result, the residual pressure adjusting valve 67 is switched to the communication position (B), and the residual oil pressure in the rod side oil chamber 5B2 of the boom cylinder 5B is supplied to the hydraulic oil tank through the tank line 66 and the return line 32A. 20 can be discharged.

The hydraulic excavator 1 according to the first embodiment drives the regenerative hydraulic motor 23 using the return oil that returns from the swing motor 19 to the hydraulic oil tank 20 when the upper swing body 4 rotates inertially on the lower traveling body 2. Rotating regenerative operation can be performed. On the other hand, when the boom 5A of the working device 5 rotates downward, a boom regenerative operation for driving the regenerative hydraulic motor 23 is performed using return oil that returns from the bottom oil chamber 5B1 of the boom cylinder 5B to the hydraulic oil tank 20. be able to. Since the regenerative energy obtained by the boom regenerative operation is larger than the regenerative energy obtained by the turning regenerative operation, the boom regenerative operation is performed with priority over the turning regenerative operation.

Here, according to the first embodiment, the regenerative hydraulic motor 23 and the regenerative electric motor 24 mounted on the upper swing body 4 are located between the hydraulic pump 14 and the hydraulic oil tank 20 and operated. The oil tank 20 is arranged in the vicinity of the oil tank 20. Thereby, the maintenance work for the regenerative hydraulic motor 23 and the maintenance work for the regenerative electric motor 24 can be performed from one common work place. As a result, the workability of the maintenance work for the regenerative unit 25 including the regenerative hydraulic motor 23 and the regenerative electric motor 24 can be improved.

In addition, by disposing the regenerative unit 25 at a position close to the hydraulic oil tank 20, the tank line 69 connecting the regenerative hydraulic motor 23 and the hydraulic oil tank 20 can be shortened. As a result, the pressure loss of the return oil that returns from the regenerative hydraulic motor 23 to the hydraulic oil tank 20 can be reduced, and the regeneration efficiency can be increased.

In the first embodiment, the regenerative hydraulic motor 23 and the regenerative electric motor 24 are arranged side by side in the left and right directions between the hydraulic pump 14 and the hydraulic oil tank 20. Thereby, the regenerative hydraulic motor 23 and the regenerative electric motor 24 can be efficiently arranged in the space formed between the hydraulic pump 14 and the hydraulic oil tank 20.

In the first embodiment, the partition unit 17 is provided on the front side of the hydraulic pump 14 so as to extend leftward and rightward, so that the regenerative unit accommodating space 21 is provided between the hydraulic oil tank 20 and the partition member 17. Is formed. Therefore, the regenerative hydraulic motor 23 and the regenerative electric motor 24 can be accommodated in a compact manner by accommodating the regenerative hydraulic motor 23 and the regenerative electric motor 24 side by side in the regenerative unit accommodation space 21 in the left and right directions. it can.

Further, the excavator 1 according to the first embodiment is provided with a right side door 31 at a position corresponding to the regenerative unit 25 in the building cover 27. The right side door 31 includes a right rear side door 31A that covers the hydraulic pump 14 and the like so that it can be opened and closed from the right side, and a right front side door that covers the regenerative hydraulic motor 23 and the regenerative electric motor 24 so that they can be opened and closed from the right side. 31B. Thereby, when performing the maintenance with respect to the regeneration unit 25, the regeneration unit accommodation space 21 can be opened outside by opening the right rear side door 31A and the right front side door 31B. As a result, maintenance workability for the regenerative hydraulic motor 23 and the regenerative electric motor 24 accommodated in the regenerative unit accommodation space 21 can be improved.

Next, FIG. 6 and FIG. 7 show a second embodiment of the present invention. The feature of this embodiment is that a regenerative assist pump that is driven by return oil that returns from the turning device or the working device to the hydraulic oil tank is additionally provided in the regenerative unit. In the present embodiment, the same components as those in the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted.

In the figure, the regeneration unit 77 is applied to the second embodiment. The regenerative unit 77 is obtained by adding a regenerative hydraulic pump 78 as a regenerative assist pump described later in addition to the regenerative hydraulic motor 23 and the regenerative electric motor 24 constituting the regenerative unit 25 according to the first embodiment.

The regenerative hydraulic pump 78 constitutes the regenerative unit 77 and is composed of a variable displacement hydraulic pump. The regenerative hydraulic pump 78 is driven by the regenerative hydraulic motor 23 to supply pressure oil, and joins the pressure oil to the pressure oil supplied from the hydraulic pump 14.

Here, as shown in FIG. 6, the regenerative hydraulic pump 78 is adjacent to the vicinity (rear side) of the hydraulic oil tank 20, together with the regenerative hydraulic motor 23 and the regenerative electric motor 24, at a position spaced forward from the hydraulic pump 14. It is provided in the state. The pump shaft of the regenerative hydraulic pump 78 is connected to the motor shaft of the regenerative hydraulic motor 23 via a power transmission mechanism (not shown). Thus, the regenerative hydraulic motor 23, the regenerative electric motor 24, and the regenerative hydraulic pump 78 constitute a regenerative unit 77 separated from the engine 9. The regenerative hydraulic motor 23, the regenerative electric motor 24, and the regenerative hydraulic pump 78 are arranged between the hydraulic pump 14 and the hydraulic oil tank 20, more specifically, the right partition plate 17C of the partition member 17 provided on the front side of the hydraulic pump 14. Are accommodated side by side in the left and right directions in a regenerative unit housing space 21 formed between the hydraulic oil tank 20 and the hydraulic oil tank 20.

On the other hand, as shown in FIG. 7, the discharge side of the regenerative hydraulic pump 78 is connected to the delivery line 14 A via a confluence line 79, and a suction line 80 is provided between the regenerative hydraulic pump 78 and the hydraulic oil tank 20. Connected through. A junction valve 81 is connected in the middle of the junction line 79. The merging valve 81 is a two-port two-position switching valve having a pilot portion 81A, and always maintains the blocking position (A) to block the merging pipe line 79. On the other hand, the merging valve 81 is switched to the communication position (B) when a pilot signal is supplied to the pilot section 81A, and communicates the merging pipe line 79 via the throttle 81B. A check valve 82 is provided in the middle of the merge line 79 between the delivery line 14 A and the merge valve 81. The check valve 82 allows the flow of pressure oil from the regenerative hydraulic pump 78 toward the delivery pipeline 14A and prevents the reverse flow.

The hydraulic excavator according to the second embodiment includes a regenerative unit 77 to which a regenerative hydraulic pump 78 as described above is added. Therefore, as in the first embodiment, the pressure oil discharged from the turning motor 19 during the inertial rotation of the upper swing body 4 or the pressure oil discharged from the bottom side oil chamber 5B1 when the boom cylinder 5B is reduced, The regenerative hydraulic motor 23 rotates by being supplied to the regenerative hydraulic motor 23 through the turning regenerative pipeline 43, the boom regenerative pipeline 68, and the like. As a result, the regenerative hydraulic motor 23 drives the regenerative electric motor 24 and the regenerative hydraulic pump 78, the regenerative electric motor 24 generates electric power stored in the power storage device 13, and the regenerative hydraulic pump 78 is in the hydraulic oil tank 20. Hydraulic oil is discharged as pressure oil.

At this time, the controller (not shown) determines whether or not the pressure oil discharged from the regenerative hydraulic pump 78 is merged with the pressure oil discharged from the hydraulic pump 14. A pilot signal is output to 81. Thereby, the merging valve 81 is switched to the communication position (B), and the pressure oil discharged from the regenerative hydraulic pump 78 can be merged with the pressure oil discharged from the hydraulic pump 14 in the delivery pipeline 14A. As a result, the pump flow rate of the hydraulic pump 14 can be reduced by the pump flow rate of the regenerative hydraulic pump 78, and the power for driving the hydraulic pump 14 can be reduced.

On the other hand, when the pressure oil discharged from the regenerative hydraulic pump 78 is not merged with the pressure oil discharged from the hydraulic pump 14, the controller switches the merging valve 81 to the cutoff position (A) and regenerative hydraulic pump 78. Set the discharge capacity to zero.

Thus, in the second embodiment, the regenerative hydraulic pump 78 is added to the regenerative hydraulic motor 23 and the regenerative electric motor 24. Accordingly, the regenerative electric motor 24 is driven not only by using the return oil that returns from the swing motor 19 when the upper swing body 4 rotates by inertia, or the return oil that returns from the bottom-side oil chamber 5B1 when the boom cylinder 5B is reduced. The hydraulic pump 78 can be driven. As a result, in addition to storing electric power in the power storage device 13, the pressure oil discharged from the regenerative hydraulic pump 78 can be merged with the pressure oil discharged from the hydraulic pump 14. As a result, the pump flow rate of the hydraulic pump 14 can be reduced, and the power for driving the hydraulic pump 14 can be reduced.

Further, in the second embodiment, the regenerative hydraulic pump 78 is placed between the hydraulic pump 14 and the hydraulic oil tank 20 (position near the hydraulic oil tank 20) together with the regenerative hydraulic motor 23 and the regenerative electric motor 24. Are arranged together. Thereby, the maintenance work for the regenerative hydraulic motor 23, the maintenance work for the regenerative electric motor 24, and the maintenance work for the regenerative hydraulic pump 78 can be performed from one common work place. As a result, the workability of the maintenance work for the regenerative unit 77 including the regenerative hydraulic motor 23, the regenerative electric motor 24, and the regenerative hydraulic pump 78 can be improved.

In the first embodiment described above, the case where the regenerative unit 25 including the regenerative hydraulic motor 23 and the regenerative electric motor 24 is disposed between the hydraulic pump 14 and the hydraulic oil tank 20 is illustrated. However, the present invention is not limited to this. For example, a regenerative unit accommodation space 83 is formed between the hydraulic oil tank 20 and the fuel tank 22 as in the modification shown in FIG. The regeneration unit 25 may be housed inside. As a result, the regenerative hydraulic motor 23 and the regenerative electric motor 24 can be collectively disposed so as to be separated from the hydraulic pump 14 and adjacent to the front side of the hydraulic oil tank 20. In this case, the pipe line length of the tank pipe line 69 connecting the regenerative hydraulic motor 23 and the hydraulic oil tank 20 can be shortened. The same applies to the regenerative hydraulic motor 23, the regenerative electric motor 24, and the regenerative hydraulic pump 78 according to the second embodiment.

In the above-described embodiment, the hydraulic excavator 1 is illustrated as the hybrid work machine. However, the present invention is not limited to this, and can be applied to other hybrid work machines such as a wheel hydraulic excavator. .

1 Excavator (construction machine)
2 Lower traveling body 4 Upper revolving body 5 Working device 6 Revolving frame 9 Engine (motor)
DESCRIPTION OF SYMBOLS 13 Power storage device 14 Hydraulic pump 15 Assist electric motor 19 Rotating motor 20 Hydraulic oil tank 23 Regenerative hydraulic motor 24 Regenerative

electric motor

25,77 Regenerative unit 27 Building cover 31 Right side door 78 Regenerative hydraulic pump (regenerative assist pump)

Claims

A self-propelled lower traveling body (2), an upper revolving body (4) mounted on the lower traveling body (2) and revolving by a revolving motor (19), and the upper revolving body (4) can be moved up and down. And the working device (5) provided in
The upper swing body (4) includes a swing frame (6) forming a support structure,
A prime mover (9) provided on the swivel frame (6) in a horizontally installed state extending in the left and right directions;
Pressure oil is discharged toward the swing motor (19) and the actuator of the work device (5) by being provided on one side of the prime mover (9) in the left and right directions and driven by the prime mover (9). A hydraulic pump (14);
A hydraulic oil tank (20) for storing hydraulic oil provided to the swing motor (19) and the actuator of the working device (5) provided on the swing frame (6);
A power storage device (13) provided in the swivel frame (6) for storing electric power;
An assist electric motor (15) that is rotated by electric power from the power storage device (13) and assists the driving of the hydraulic pump (14) by the prime mover (9);
The regenerative hydraulic motor (23) rotated by return oil returning from the swing motor (19) or the actuator of the working device (5) to the hydraulic oil tank (20) and the power storage device driven by the regenerative hydraulic motor (23). In a hybrid work machine comprising a regenerative unit (25, 77) configured to include a regenerative electric motor (24) that generates electric power stored in (13),
The hydraulic oil tank (20) is located on the front side of the hydraulic pump (14) and is provided on the turning frame (6).
The hybrid characterized in that the regenerative hydraulic motor (23) and the regenerative electric motor (24) constituting the regenerative unit (25) are arranged in the vicinity of the hydraulic oil tank (20). Type work machine.
The regenerative hydraulic motor (23) and the regenerative electric motor (24) constituting the regenerative unit (25, 77) are arranged between the hydraulic pump (14) and the hydraulic oil tank (20). The hybrid work machine according to claim 1.
The regenerative hydraulic motor (23) and the regenerative electric motor (24) constituting the regenerative unit (25, 77) are located between the hydraulic pump (14) and the hydraulic oil tank (20), and The hybrid work machine according to claim 1, wherein the hybrid work machine is configured to be arranged side by side in a left direction and a right direction.
Provided on the front side of the hydraulic pump (14) is a partition member (17) erected on the swivel frame (6) in a state extending in the left and right directions,
A regenerative unit accommodating space (21) is formed between the hydraulic oil tank (20) and the partition member (17),
The regenerative hydraulic motor (23) and the regenerative electric motor (24) constituting the regenerative unit (25, 77) are configured to be accommodated side by side in the left and right directions in the regenerative unit accommodation space (21). Item 2. The hybrid work machine according to Item 1.
The swivel frame (6) is provided with a building cover (27) for accommodating the prime mover (9), the hydraulic pump (14), and the regenerative unit (25, 77), and the building cover (27) The position corresponding to the regeneration unit (25, 77) is provided with a door (31B) that is opened and closed when maintenance work is performed on the regeneration unit (25, 77). Hybrid work machine.
The regenerative unit (77) is driven by return oil that returns to the hydraulic oil tank (20) from the actuators of the swing motor (9) and the work device (5), and pressure oil from the hydraulic pump (14). A regenerative assist pump (78) for discharging the pressure oil that joins the
The regenerative assist pump (78) is arranged between the hydraulic pump (14) and the hydraulic oil tank (20) together with the regenerative hydraulic motor (23) and the regenerative electric motor (24). The hybrid work machine according to claim 1.