JP2006336305A - Work machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a work machine for surely providing high pressure required by a bucket control circuit, by making the bucket control circuit independent. <P>SOLUTION: The control circuit 37 for a work device has a boom control circuit 45 for controlling a working fluid supplied to a boom cylinder 8bmc from main pumps 17A and 17B of a hybrid type driving device 10, a stick control circuit 46 for controlling the working fluid supplied to a stick cylinder 8stc from the main pumps 17A and 17B of the hybrid type driving device 10, and the bucket control circuit 47 for driving a bucket pump 82 by an electric motor 81 for a bucket operated by electric power supplied from a capacitor 23 of the hybrid type driving device 10 and controlling the working fluid supplied to a bucket cylinder 8bkc from this bucket pump 82. A revolution control circuit 28 has a motor-driven generator 4sw for revolution operated by the electric power from the capacitor 23 of the hybrid type driving device 10. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a work machine including a hybrid drive device.

BACKGROUND ART A drive device for a work machine such as a hydraulic excavator has a hybrid drive device that includes a generator driven by an engine and a capacitor that stores electric power generated by the generator. An electric motor or an electric motor / generator operated by electric power supplied from at least one of these generators and capacitors drives a pump or a pump motor. For example, a boom control circuit for controlling a boom cylinder operates a motor / generator by electric power supplied from a generator or a capacitor to drive a pump / motor, and a stick for controlling a stick cylinder. The control circuit for operating the stick operates by driving the electric motor for the stick with the electric power supplied from the generator or the condenser, and further, the control circuit for the bucket for controlling the bucket cylinder includes the generator Alternatively, the bucket motor is driven by the electric power supplied from the capacitor to drive the bucket pump. The boom control circuit, the stick control circuit, and the bucket control circuit are connected by a plurality of support circuits that mutually supplement the working fluid (see, for example, Patent Document 1).
JP 2004-190845 A (first page, FIG. 1)

  In the boom control circuit, a large flow rate is required, whereas in the bucket control circuit, a high pressure is required. Therefore, it is not easy to reliably control a plurality of support circuits so as to satisfy these requirements. .

  The present invention has been made in view of these points, and an object of the present invention is to provide a work machine that can reliably obtain the high pressure required by the bucket control circuit by making the bucket control circuit independent. To do.

  According to the first aspect of the present invention, an upper swing body that can be swung by a turning electric motor / generator is provided for a lower traveling body that can travel by a travel motor, and a boom that is rotated by a boom cylinder on the upper swing body. A working machine provided with a working device in which a stick rotated by a stick cylinder and a bucket rotated by a bucket cylinder are sequentially connected, and functions as a generator driven by the engine. An electric motor / generator that functions as an electric motor upon receipt of electric power, and a capacitor that stores electric power supplied from the electric motor / generator that functions as the electric generator and supplies electric power to the electric motor / generator that functions as an electric motor; A hybrid drive device comprising a main pump driven by at least one of an engine and an electric motor / generator A traveling control circuit for controlling the working fluid supplied from the main pump of the hybrid drive device to the traveling motor, and a boom control circuit for controlling the working fluid supplied from the main pump of the hybrid drive device to the boom cylinder A control circuit for the stick that controls the working fluid supplied from the main pump of the hybrid drive device to the stick cylinder, and a bucket motor that is operated by electric power supplied from the electric storage device of the hybrid drive device. The bucket control circuit that drives and controls the working fluid supplied from the bucket pump to the bucket cylinder, and the upper part operates the turning motor / generator as an electric motor by the electric power supplied from the capacitor of the hybrid drive device. When turning the swinging body, A swing control circuit that collects electric power generated from the swiveling electric motor / generator that is operated by the electric accumulator, and the boom control circuit is provided in a return fluid passage through which the return fluid recovered from the boom cylinder passes. A work machine including an energy regenerative motor and a generator that is driven by the energy regenerative motor to supply electric power to a capacitor of a hybrid drive device.

  According to a second aspect of the present invention, there are provided two main pumps in the work machine according to the first aspect, the working fluid supply passage for the boom cylinder supplying the working fluid from one main pump to the control circuit for the boom, and the other. Circuit communication between the boom and the stick that connects the working fluid supply passage for the stick cylinder that supplies the working fluid from the main pump to the stick control circuit, and the working fluid supply passage for the boom cylinder and the working fluid supply passage for the stick cylinder Position in the communication passage between the passage and the circuit between the boom and stick, allowing the one-way flow from the boom control circuit to the stick control circuit, the position allowing the bidirectional flow, and the bidirectional flow. And a solenoid valve between the boom and the stick having a neutral position for blocking.

  According to the first aspect of the present invention, the traveling control circuit, the boom control circuit, and the stick control circuit that receive the supply of the working fluid from the main pump of the hybrid drive apparatus are supplied from the capacitor of the hybrid drive apparatus. The bucket pump is driven by the bucket motor that is operated by the generated electric power, and the bucket control circuit that controls the working fluid supplied from the bucket pump to the bucket cylinder is installed independently. The high voltage required by the bucket control circuit can be reliably obtained without being affected by the control circuit for boom, the control circuit for boom, and the control circuit for stick.

  According to the second aspect of the present invention, it is possible to supply the flow rate from the boom control circuit to the stick control circuit by the boom-stick electromagnetic valve provided in the inter-circuit communication path between the boom and stick. At the same time, the flow from the stick control circuit to the boom control circuit can be supplied, and the boom-stick solenoid valve is controlled to the neutral position to separate the boom control circuit from the stick control circuit. It can also be made.

  Hereinafter, the present invention will be described in detail with reference to one embodiment shown in FIGS. Note that oil and hydraulic pressure are used as the fluid and the fluid pressure.

  As shown in FIG. 2, the work machine 1 is a hydraulic excavator, and an upper swing body 4 is rotatably provided on a lower traveling body 2 via a swing bearing portion 3. A power unit 5 such as a fluid pressure pump, a cab 6 that protects an operator, and the like are mounted to form an airframe 7. The lower traveling body 2 includes traveling motors 2trL and 2trR for driving the left and right crawler belts, and the upper revolving body 4 is a turning electric motor for driving a turning speed reduction mechanism provided in the turning bearing portion 3. A generator (not shown in FIG. 2) is provided.

  A work device 8 is attached to the upper swing body 4. In this working device 8, a boom (8bm), a stick 8st, and a bucket 8bk are pin-coupled to a bracket (not shown) of the upper swing body 4 so as to be sequentially rotatable, the boom 8bm is rotated by a boom cylinder 8bmc, It is rotated by the stick cylinder 8stc, and the bucket 8bk is rotated by the bucket cylinder 8bkc.

  In the hybrid drive device 10 shown in FIG. 1, a clutch 12 that connects and disconnects rotational power output from the engine 11 is connected to an engine 11, and an input shaft 13 of a power transmission device 14 is connected to the clutch 12. Two variable capacity main pumps 17A and 17B are connected to the output shaft 15 of the power transmission device.

  The main pumps 17A and 17B are driven by the engine 11 to function as a generator and function as a motor by being supplied with electric power to the input / output shaft 21 of the power transmission device 14 in a parallel relationship with the engine 11. A motor / generator 22 is connected. The motor power of the motor / generator 22 is set smaller than the engine power. The motor / generator 22 is connected to a motor / generator controller 22c such as an inverter.

  The motor / generator controller 22c stores electric power supplied from the motor / generator 22 that functions as a generator and stores electric power to the motor / generator 22 that functions as a motor via a capacitor controller 23c such as a converter. A capacitor 23 to be supplied is connected. The battery 23 is a battery, a capacitor, or the like.

  The power transmission device 14 in the hybrid drive device 10 incorporates a continuously variable transmission mechanism such as a toroidal type or a planetary gear type, and can output the continuously variable rotation to the output shaft 15 by an external control signal. Yes.

  The main pumps 17A and 17B in the hybrid drive device 10 supply a working fluid such as hydraulic oil stored in the tank 24 to the fluid pressure actuator control circuit 25. An energy regenerative motor 26 is provided in the fluid pressure actuator control circuit 25, and electric power recovered from a generator 27 driven by the energy regenerative motor 26 via a generator controller 27c such as a converter is stored in a capacitor. Stored in 23.

  With respect to the fluid pressure actuator control circuit 25, the turning electric motor / generator 4sw is operated as an electric motor by the electric power supplied from the capacitor 23 of the hybrid drive device 10, and the upper rotating body 4 is operated as a generator at the time of turning braking. A turning control circuit 28 for collecting the electric power generated from the turning electric motor / generator 4sw in the battery 23 is installed.

  This turning control circuit 28 includes a turning electric motor / generator 4sw for turning the upper turning body 4 via a turning speed reduction mechanism 4gr, and a turning electric / generator controller 4swc such as an inverter. The electric power supplied from the electric storage device 23 of the driving device 10 functions as an electric motor, and when it is forcibly rotated by the inertial turning force, the electric motor 23 functions as an electric generator, collects electric power in the electric storage device 23, and is used for driving the electric motor.

  The speed of the engine 11, the engagement / disengagement of the clutch 12, the speed change of the power transmission device 14, and the like are controlled by signals output from a controller (not shown).

  In the fluid pressure actuator control circuit 25 shown in FIG. 1, the pump passages 31 and 32 connected to the discharge ports of the main pumps 17A and 17B operate as electromagnetic proportional valves provided in the bypass passages returned to the tank 24. Are connected to electromagnetic valves 33 and 34, and are also connected to an electromagnetic valve 35 that operates as a straight traveling valve.

  The solenoid valves 33 and 34 function as bypass valves. When there is no operation signal for the operator to operate the fluid pressure actuators 2trL, 2trR, 8bmc, 8stc, and 8bkc, the pump passages 31 and 32 are tanked by the control signal from the controller. 24 is controlled to the fully open position, and the operator is displaced to the closed position in proportion to the magnitude of the operation signal for operating the fluid pressure actuators 2trL, 2trR, 8bmc, 8stc, and 8bkc.

  The solenoid valve 35 can supply the working fluid from the two main pumps 17A, 17B to the fluid pressure actuators 2trL, 2trR, 8bmc, 8stc, 8bkc at the left working position shown in FIG. When switched, the working fluid equally divided into the two traveling motors 2trL and 2trR is supplied from only one main pump 17B, and straight traveling is enabled.

  The fluid pressure actuator control circuit 25 includes a travel control circuit 36 that controls the working fluid supplied from the main pumps 17A and 17B of the hybrid drive device 10 to the travel motors 2trL and 2trR, and the main pump 17A of the hybrid drive device 10. , 17B, a working device control circuit 37 for controlling the working fluid supplied to the working actuators 8bmc, 8stc, 8bkc for operating the working device 8.

  The traveling control circuit 36 includes electromagnetic valves 43 and 44 for controlling the direction and flow rate of the working fluid supplied through the working motor working fluid supply passages 41 and 42 drawn from the electromagnetic valve 35 that operates as a straight traveling valve. I have.

  The work device control circuit 37 includes a boom control circuit 45 that controls the working fluid supplied from the main pumps 17A and 17B of the hybrid drive device 10 to the boom cylinder 8bmc, and the main pumps 17A and 17B of the hybrid drive device 10. The bucket pump 82 is driven by a stick control circuit 46 that controls the working fluid supplied from the battery to the stick cylinder 8stc, and a bucket motor 81 that is operated by electric power supplied from the capacitor 23 of the hybrid drive device 10. A bucket control circuit 47 for controlling the working fluid supplied from the bucket pump 82 to the bucket cylinder 8bkc. The rotation speed of the bucket motor 81 is controlled by a bucket motor controller 81c such as an inverter connected to a controller (not shown).

  The boom control circuit 45 includes an electromagnetic valve 49 that controls the direction and the flow rate of the working fluid supplied through the boom cylinder working fluid supply passage 48 drawn from the solenoid valve 35 that operates as a straight traveling valve. The working fluid supply / discharge passages 51 and 52 of the valve 49 are communicated with the head side chamber and the rod side chamber of the boom cylinder 8bmc.

  In the working fluid supply / discharge passage 51 on the head side, an electromagnetic valve 53 functioning as a fall prevention valve is interposed. When the boom is stopped, the electromagnetic valve 53 is controlled to be switched to the check valve position on the left side and lowered by the weight of the boom 8bm. To prevent. Further, an electromagnetic valve 54 functioning as a regeneration valve is provided between both the working fluid supply / discharge passages 51 and 52, and this solenoid valve 54 is controlled to be switched to the check valve position when the boom is lowered, so that the head of the boom cylinder 8bmc A part of the return fluid discharged from the side chamber is regenerated into the rod side chamber.

  On the tank passage side of the solenoid valve 49, a return fluid passage 55 for diverting the return fluid discharged from the boom cylinder 8bmc is provided, and in one return passage 56 and the other return passage 57 of the return fluid passage 55, Flow ratio control valves 58 and 59 for controlling the flow ratio of the flow divided into the return passages 56 and 57 are provided. The flow ratio control valves 58 and 59 are branched on one upstream side of the one electromagnetic valve 58 and one electromagnetic valve 58 for flow control provided in one return passage 56 having the energy regeneration motor 26. The other return valve 57 is provided with the other electromagnetic valve 59 for flow rate control.

  Then, the rotational speed of the energy regenerative motor 26 to be operated is controlled by the amount of return fluid in one of the return passages 56 whose flow rate is controlled by the flow rate control valves 58 and 59, and the generator driven by this energy regenerative motor 26 According to 27, electric power is supplied to and stored in the battery 23 of the hybrid drive device 10.

  The energy regeneration motor 26 is preferably operated when the electromagnetic valve 49 for direction control and flow rate control is in the right ventricle in FIG. That is, when the boom is lowered, the working fluid supply / discharge passage 51 on the head side of the boom cylinder 8bmc communicates with the return fluid passage 55, and the energy regeneration motor 26 is caused by the boom's own weight by the return fluid discharged from the head side of the boom cylinder 8bmc. It is desirable to operate with a margin.

  The stick control circuit 46 includes an electromagnetic valve 62 that controls the direction and the flow rate of the working fluid supplied through the stick cylinder working fluid supply passage 61 drawn from the solenoid valve 35 that operates as a straight traveling valve. The working fluid supply / discharge passages 63 and 64 of the valve 62 communicate with the head side chamber and the rod side chamber of the stick cylinder 8stc. In addition, an electromagnetic valve 65 that functions as a regeneration valve from the rod side to the head side is provided between both working fluid supply / discharge passages 63 and 64, and this solenoid valve 65 is switched to the check valve position when the stick-in is lowered. By controlling, the return fluid discharged from the rod side chamber of the stick cylinder 8stc is regenerated into the head side chamber.

  The bucket control circuit 47 drives the bucket pump 82 by the bucket electric motor 81 that is operated by the electric power supplied from the battery 23 of the hybrid drive device 10, and the working fluid supplied from the bucket pump 82 An electromagnetic valve 67 that controls the direction and the flow rate is provided, and the working fluid supply / discharge passages 68 and 69 of the electromagnetic valve 67 are communicated with the head side chamber and the rod side chamber of the bucket cylinder 8bkc.

  Between the boom cylinder working fluid supply passage 48 and the stick cylinder working fluid supply passage 61, there is provided an inter-circuit communication passage 73 between the boom and the stick that communicates between them. In the inter-communication passage 73, the position allowing the one-way flow from the boom cylinder working fluid supply passage 48 to the stick cylinder working fluid supply passage 61, the position allowing the two-way flow, and the two-way flow are blocked. An electromagnetic valve 83 between the boom and stick having a neutral position is provided.

  The solenoid valves 53, 54, 65, and 83 are switching valves having a flow rate adjustment function with a built-in check valve.

  Solenoid valves 33, 34, 35, 43, 44, 49, 53, 54, 58, 59, 62, 65, 67, 83 are a solenoid proportionally controlled by a controller (not shown), a return spring (not shown), The displacement is controlled to a position where the solenoid exciting force and the spring restoring force are balanced.

  Next, the function and effect of the illustrated embodiment will be described.

  The travel control circuit 36, the boom control circuit 45, and the stick control circuit 46 that are supplied with the working fluid from the main pumps 17A and 17B of the hybrid drive apparatus 10 are supplied from the capacitor 23 of the hybrid drive apparatus 10. A bucket control circuit 47 that drives the bucket pump 82 by the bucket motor 81 that is operated by the generated electric power and controls the working fluid supplied from the bucket pump 82 to the bucket cylinder 8bkc is installed independently. Thus, the high pressure required by the bucket control circuit 47 can be obtained reliably without being affected by the travel control circuit 36, the boom control circuit 45, and the stick control circuit 46.

  At this time, by controlling the rotational speed of the bucket motor 81 by a controller (not shown), the discharge flow rate of the bucket pump 82 is variably controlled, and the working fluid supplied from the bucket pump 82 to the bucket cylinder 8bkc Is controlled in direction by an electromagnetic valve 67 operated by an electric signal from a controller (not shown).

  The boom control circuit 45 diverts the return fluid discharged from the boom cylinder 8bmc in the return fluid passage 55, and controls the diverted flow rate ratio by the flow rate control valves 58 and 59. The energy regenerative motor 26 is operated by one return fluid whose flow rate is controlled by the valves 58 and 59, and the generator 27 is driven by the energy regenerative motor 26 to supply electric power to the capacitor 23 of the hybrid drive device 10. , By gradually increasing the flow rate ratio that is diverted to the energy regenerative motor 26 from the time when the return fluid from the boom cylinder 8bmc is generated, it is possible to prevent the occurrence of shock and to suppress sudden load fluctuations of the boom cylinder 8bmc Thus, stable operation of the boom cylinder 8bmc can be obtained.

  That is, when the boom 8bm of the working device 8 falls by its own weight, the return fluid discharged from the head side of the boom cylinder 8bmc is gradually increased in flow rate ratio to the energy regeneration motor 26 side, so that the energy of the return fluid is increased. Can be absorbed smoothly by the energy regeneration motor 26, and a sudden load fluctuation on the head side of the boom cylinder 8bmc can be suppressed, so that the weight falling operation of the boom 8bm can be stabilized.

  Furthermore, one electromagnetic valve 58 and the other electromagnetic valve 59 can be installed separately at any location of one return passage 56 and the other return passage 57, respectively, and one return passage 56 and the other return passage The flow rate ratio and flow rate of the return fluid flowing to the energy regeneration motor 26 side can be freely controlled by individually controlling the opening degree of 57 without being related to each other.

  The turning control circuit 28 operates the turning electric motor / generator 4sw as an electric motor when turning the upper turning body 4 with respect to the lower traveling body 2, and stops the upper turning body 4 during turning. The turning electric motor / generator 4sw is operated as a generator to brake the turning of the upper turning body 4, and the electric power generated from the turning electric motor / generator 4sw is generated by the energy regeneration motor 26. The electric power generated from the machine 27 can be efficiently recovered in the battery 23 of the hybrid drive device 10 and can be effectively regenerated as the pump power of the hybrid drive device 10. Thereby, the fuel efficiency of the engine 11 of the hybrid drive device 10 can be improved.

  Also, by controlling the solenoid valve 83 provided in the circuit-to-circuit communication path 73 between the boom and stick to a position where one-way flow or a two-way flow is possible, the boom control circuit 45 can The flow rate can be supplied to the control circuit 46, that is, the working fluid supplied from one main pump 17A to the boom cylinder 8bmc is joined to the working fluid supplied from the other main pump 17B to the stick cylinder 8stc, The speed of the stick cylinder 8stc can be increased.

  Further, by controlling the solenoid valve 83 between the boom and stick to a position where bidirectional flow is possible, it is possible to supply a flow rate from the stick control circuit 46 to the boom control circuit 45, that is, another main pump 17B. From the main pump 17A through the boom cylinder working fluid supply passage 48 and the left chamber of the directional control solenoid valve 49 to the head side of the boom cylinder 8bmc. By merging with the fluid, the two main pump flow rates can be merged to speed up the boom-up operation.

  Furthermore, when the boom-stick electromagnetic valve 83 is controlled to the neutral position and the boom control circuit 45 and the stick control circuit 46 are separated and independent, the boom system and the stick system are separated from each other, Can be controlled separately.

  Also, by making the swing system and bucket system independent of the fluid circuit of the boom cylinder 8bmc and stick cylinder 8stc that receive the supply of working fluid from the main pumps 17A and 17B, the boom cylinder 8bmc and stick cylinder 8stc can be operated at high speed. Workability can be improved.

1 is a circuit diagram showing an embodiment of a hybrid drive device for a work machine and a fluid pressure actuator control circuit according to the present invention. It is a side view of a working machine same as the above.

Explanation of symbols

1 Working machine 2 Lower traveling body
2trL, 2trR Travel motor 4 Upper swing body
4sw Electric motor / generator for turning 8 Working device
8bm boom
8st stick
8bk bucket
8bmc boom cylinder
8stc stick cylinder
8bkc bucket cylinder
10 Hybrid drive unit
11 engine
17A, 17B main pump
22 Electric generator
23 Battery
26 Energy regeneration motor
27 Generator
28 Control circuit for turning
36 Driving control circuit
45 Boom control circuit
46 Control circuit for stick
47 Bucket control circuit
48 Working fluid supply passage for boom cylinder
55 Return fluid passage
61 Working fluid supply passage for stick cylinder
73 Communication path between circuits
81 Electric motor for bucket
82 Bucket pump
83 Solenoid valve

Claims (2)

An upper turning body that can be turned by a turning electric motor / generator is provided for a lower traveling body that can be driven by a traveling motor, and the upper turning body is rotated by a boom and a stick cylinder that are rotated by a boom cylinder. A working machine provided with a working device that sequentially connects a stick and a bucket rotated by a bucket cylinder,
An engine, an electric motor / generator driven by the engine and functioning as a generator and receiving electric power to function as an electric motor, and an electric motor that stores electric power supplied from the electric motor / generator functioning as the electric generator A hybrid drive device comprising a battery for supplying electric power to the motor / generator functioning as a main pump driven by at least one of the engine and the motor / generator;
A travel control circuit for controlling the working fluid supplied from the main pump of the hybrid drive device to the travel motor;
A boom control circuit for controlling the working fluid supplied from the main pump of the hybrid drive device to the boom cylinder;
A control circuit for the stick that controls the working fluid supplied to the stick cylinder from the main pump of the hybrid drive device;
A bucket control circuit for driving a bucket pump by a bucket motor operated by electric power supplied from a capacitor of a hybrid drive device and controlling a working fluid supplied from the bucket pump to a bucket cylinder;
The electric motor / generator for turning is operated as an electric motor by the electric power supplied from the electric storage device of the hybrid drive device, and the electric power generated from the electric motor / generator for turning operated as the electric generator at the time of turning braking of the upper revolving structure is collected in the electric storage device. A control circuit for turning,
The boom control circuit
An energy regenerative motor provided in a return fluid passage through which a return fluid recovered from the boom cylinder passes;
A work machine comprising: a generator that is driven by the energy regenerative motor and supplies electric power to a battery of a hybrid drive device. There are two main pumps,
A working fluid supply passage for the boom cylinder that supplies working fluid from one main pump to the boom control circuit;
A working fluid supply passage for the stick cylinder that supplies the working fluid from the other main pump to the control circuit for the stick;
A communication path between the boom and the stick that communicates the working fluid supply passage for the boom cylinder and the working fluid supply passage for the stick cylinder;
Position in the inter-circuit communication path between the boom and stick that allows one-way flow from the boom control circuit to the stick control circuit, a position that allows bidirectional flow, and a neutral that blocks bidirectional flow The work machine according to claim 1, further comprising: a solenoid valve between the boom and the stick having a position.

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