JP2006336433A - Hydraulic pressure circuit of work machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To supply a working fluid of a large flow rate to the head side of a boom cylinder. <P>SOLUTION: An inter-circuit communicating passage 71 between stick booms is arranged between a working fluid supply passage 61 for a stick cylinder and the head side of the boom cylinder 8bmc. A solenoid valve 72 between the stick booms is arranged in this inter-circuit communicating passage 71 to be displaced between a position capable of a unidirectional flow to the head side of the boom cylinder 8bmc from the working fluid supply passage 61 and a position for cutting off the flow. In a working fluid supply passage 48 for the boom cylinder, a solenoid valve 89 between bucket booms displaced between a position capable of supplying the working fluid to a bucket cylinder 8bkc as a unidirectional flow to the boom cylinder 8bmc and a position for cutting the flow, is arranged between a branch part of a working fluid supply passage 66 for a bucket cylinder and a confluent part from a boom assist pump 84as. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fluid pressure circuit of a work machine having a boom assist pump.

  There is a drive device for a work machine in which a support circuit for supplementing a working fluid is provided between a plurality of drive circuits that drive fluid pressure actuators for a plurality of work devices by a working fluid pressure generated from a pump or a pump motor.

These excavation circuits can, for example, excavate hydraulic excavators during excavation work by replenishing hydraulic oil from the boom cylinder drive circuit with a low required flow rate to the stick cylinder drive circuit. The hydraulic fluid can be replenished to the boom cylinder drive circuit that requires a flow rate from the drive circuit of the small bucket cylinder. The hydraulic oil can be replenished to the drive circuit of the cylinder (see, for example, Patent Document 1).
Japanese Patent Laying-Open No. 2004-190845 (page 16, FIG. 1)

  The support circuit replenishes the working fluid among a plurality of fluid pressure actuators, but there are cases where the replenishment amount of the working fluid is not sufficient. For example, in a boom-up operation in which the boom cylinder of a hydraulic excavator is extended to raise the boom, the working fluid supply flow rate required by the large-diameter boom cylinder cannot be obtained, and the working speed may decrease.

  The present invention has been made in view of these points, and an object of the present invention is to provide a fluid pressure circuit for a working machine that can supply a large flow rate of working fluid to the head side of the boom cylinder.

  According to the first aspect of the present invention, a boom rotated by a boom cylinder that receives supply of working fluid from a plurality of main pumps, a stick rotated by a stick cylinder, and a bucket rotated by a bucket cylinder are sequentially connected. A fluid pressure circuit for a working machine equipped with a working device, the working fluid supply passage for a boom cylinder supplying working fluid from one main pump to the boom cylinder, and the bucket cylinder branched from the working fluid supply passage for the boom cylinder A working fluid supply passage for the bucket cylinder that supplies the working fluid to the stick, a working fluid supply passage for the stick cylinder that supplies the working fluid from another main pump to the stick cylinder, and a working fluid supply passage for the boom cylinder together with one main pump. A boom assist pump for supplying working fluid; The working fluid supply passage for the boom cylinder is provided between the branching portion of the working fluid supply passage for the bucket cylinder and the junction from the boom assist pump, and supplies the working fluid to the bucket cylinder as a one-way flow to the boom cylinder. The solenoid valve between the bucket and the boom that is displaced between the position where the flow is allowed and the position where the flow is blocked, and the space between the stick and the boom that can be communicated to the head side of the boom cylinder from the working fluid supply passage for the stick cylinder A position where the working fluid to the stick cylinder can be supplied as a one-way flow to the head side of the boom cylinder and a position where the flow is blocked. It is the fluid pressure circuit of the working machine provided with the solenoid valve between the stick and boom displaced between.

  According to a second aspect of the present invention, in the fluid pressure circuit of the working machine according to the first aspect, an energy regenerative motor that is operated by the energy of the return fluid discharged from the boom cylinder, and a capacitor that is driven by the energy regenerative motor. The motor / generator functions as a motor that functions as a generator that supplies power to the battery and that also functions as a motor by the power supplied from the capacitor, and when the motor / generator functions as a motor, power is supplied from the motor / generator to the boom assist pump. And a clutch for separating the motor / generator from the boom assist pump when functioning as a generator.

  According to the first aspect of the present invention, the working fluid from one main pump to the bucket cylinder is supplied to the boom cylinder via the electromagnetic valve between the bucket and the boom, and the working fluid from the other main pump to the stick cylinder is sticked.・ Besides supplying the boom cylinder head via the solenoid valve between the booms, the boom assist pump supplies the boom cylinder with working fluid. Speeding up, and workability can be improved. On the other hand, a predetermined working fluid pressure required for the bucket cylinder and the stick cylinder can be secured by displacing each solenoid valve to a position where the flow is blocked.

  According to the second aspect of the present invention, the clutch is disengaged to efficiently input power to the unloaded electric motor / generator from the energy regenerative motor operated by the return fluid discharged from the boom cylinder. The generated electric power can be stored in the accumulator, and when the clutch is connected, the boom assist pump is driven by the electric motor / generator functioning as an electric motor by the electric power from the accumulator, and the boom assist pump operates from the boom assist pump to the boom cylinder. Since the fluid can be supplied, the energy of the return fluid discharged from the boom cylinder can be effectively regenerated even in the open circuit.

  Hereinafter, the present invention will be described in detail with reference to one embodiment shown in FIGS. 1 and 2 and another embodiment shown in FIG.

  First, an embodiment shown in FIGS. 1 and 2 will be described.

  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 is recovered from a boom motor / generator 87 driven by the energy regenerative motor 26 via a generator controller 27c such as a converter thereof. Electric power is stored in the battery 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 an inertial turning force, it functions as an electric generator and collects electric power in the electric storage device 23.

  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).

  FIG. 1 shows a fluid pressure actuator control circuit 25. Pump passages 31 and 32 connected to discharge ports of main pumps 17A and 17B operate as electromagnetic proportional valves provided in a bypass passage returned to a tank 24. It is connected to electromagnetic valves 33 and 34, and is connected to an electromagnetic valve 35 that operates as a travel straight 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. Stick control circuit 46 for controlling the working fluid supplied from the main pumps 17A, 17B of the hybrid drive device 10 to the bucket cylinder 8bkc, and a bucket control circuit 47 for controlling the working fluid supplied to the bucket cylinder 8bkc It has.

  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 head side working fluid supply / discharge passage 51, an electromagnetic valve 53 functioning as a fall prevention valve is interposed, and when the boom is stopped, the solenoid valve 53 is controlled to be switched to the check valve position on the left side to lower the boom 8bm by its own weight. 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.

  In the boom cylinder working fluid supply passage 48 for supplying the working fluid from the main pumps 17A, 17B of the hybrid drive device 10 to the boom cylinder 8bmc, a boom assist pump 84as for assisting the flow rate of the working fluid is provided. An electromagnetic valve 86 of a bypass passage that is connected via a supply passage 85 and operates similarly to the electromagnetic valves 33 and 34 is connected.

  The energy regenerative motor 26 provided in one return passage 56 through which the return fluid discharged from the boom cylinder 8bmc passes is driven by the energy regenerative motor 26 to supply power to the battery 23 of the hybrid drive device 10. A boom motor / generator 87 is connected to the boom assist pump 84as via the clutch 88.The boom motor / generator 87 functions as a generator and functions as an electric motor by the electric power supplied from the capacitor 23. ing. The clutch 88 transmits power to the boom assist pump 84as from the boom motor / generator 87 that functions as an electric motor, and disconnects the boom motor / generator 87 that functions as a generator from the boom assist pump 84as.

  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 for the boom driven by this energy regenerative motor 26 Electric power is supplied to and stored in the battery 23 of the hybrid drive device 10 by the motor / generator 87.

  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 head side working fluid supply / discharge passage 51 of the boom cylinder 8bmc communicates with the return fluid passage 55, and the energy regenerative motor 26 is spared by the boom's own weight due to the return fluid discharged from the head side of the boom cylinder 8bmc. It is desirable to operate with

  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 includes an electromagnetic valve 67 that controls the direction and the flow rate of the working fluid supplied through the bucket cylinder working fluid supply passage 66 drawn from the solenoid valve 35 that operates as a straight traveling valve. The working fluid supply / discharge passages 68 and 69 of the valve 67 are communicated with the head side chamber and the rod side chamber of the bucket cylinder 8bkc.

  Between the stick cylinder working fluid supply passage 61 and the head side of the boom cylinder 8bmc, there is provided a circuit-to-circuit communication passage 71 between the stick and boom that communicates these, and a circuit-to-circuit communication passage 71 between the stick and boom. The stick-to-boom solenoid valve 72 is displaced between a position allowing the one-way flow from the stick cylinder working fluid supply passage 61 to the head side of the boom cylinder 8bmc and a position blocking the flow. Is provided.

  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 bucket and the stick which communicates between them. In the inter-communication passage 73, there is provided an electromagnetic valve 74 between the bucket and the stick that has a position that allows a one-way flow from the boom cylinder working fluid supply passage 48 to the stick cylinder 8stc and a position that blocks it. .

  In the boom cylinder working fluid supply passage 48, between the branch portion of the bucket cylinder working fluid supply passage 66 and the junction from the boom assist pump 84as, the working fluid to the bucket cylinder 8bkc is supplied to the boom cylinder 8bmc. An electromagnetic valve 89 between the bucket and the boom is provided which is displaced between a position where supply is possible as a one-way flow to the position and a position where flow is interrupted.

  The solenoid valves 53, 54, 65, 72, 74, and 89 are switching valves that have a flow rate adjusting function with a built-in check valve.

  Solenoid valves 33, 34, 35, 43, 44, 49, 53, 54, 58, 59, 62, 65, 67, 72, 74, 86, 89 are a solenoid that is proportionally controlled by a controller (not shown), and a return spring (Not shown), and displacement control is performed at 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 fluid pressure actuator control circuit 25 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, the boom cylinder 8bmc, the stick cylinder 8stc, and the bucket cylinder 8bkc. By disconnecting 88, power is efficiently input from the energy regenerative motor 26 operated by the return fluid discharged from the boom cylinder 8bmc to the boom motor / generator 87 in the no-load state. The boom assist pump can be stored in the battery 23 of the hybrid drive device 10 and when the clutch 88 is connected, the boom motor / generator 87 functions as an electric motor with the electric power from the battery 23 of the hybrid drive device 10. 84as is driven and working fluid is supplied from the boom assist pump 84as to the boom cylinder 8bmc. Therefore, the energy of the return fluid discharged from the boom cylinder 8bmc can be effectively regenerated even in the open circuit.

  In particular, when the boom 8bm of the work device 8 falls by its own weight, the energy of the return fluid discharged from the head side of the boom cylinder 8bmc is absorbed by the boom electric motor / generator 87 from the energy regenerative motor 26 and hybrid type. It can be efficiently stored in the battery 23 of the driving device 10.

  At this time, the return fluid discharged from the boom cylinder 8bmc to the return fluid passage 55 is divided into one return passage 56 and the other return passage 57, and the divided flow ratio is controlled by the flow ratio control valves 58 and 59. Then, the energy regenerative motor 26 is operated by one return fluid whose flow rate is controlled by the flow rate control valves 58 and 59, and the electric motor / generator 87 for the boom is driven by the energy regenerative motor 26, so that the hybrid drive device Since the electric power is supplied to the ten capacitors 23, it is possible to prevent the occurrence of shock by gradually increasing the flow rate ratio of the flow diverted to the energy regenerative motor 26 from the time when the return fluid from the boom cylinder 8bmc is generated. Stable operation of the boom cylinder 8bmc can be obtained by suppressing rapid load fluctuation of the cylinder 8bmc.

  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.

  The flow ratio control valves 58, 59 can be installed with one solenoid valve 58 and the other solenoid valve 59 separately at any place in one return passage 56 and the other return passage 57, respectively. It is possible to freely control the flow rate ratio and flow rate of the return fluid flowing to the energy regeneration motor 26 side by individually controlling the opening degrees of the passage 56 and the other return passage 57 without being related to each other.

  Further, when the upper turning body 4 turned by the turning electric motor / generator 4sw operating as the electric motor with respect to the lower traveling body 2 is stopped, the turning control circuit 28 sets the turning electric motor / generator 4sw as the generator. By operating, the turning of the upper swing body 4 can be braked, and the electric power generated from the electric motor / generator 4sw for turning is combined with the electric power generated from the electric motor / generator 87 for the boom driven by the energy regeneration motor 26. It can be efficiently recovered in the battery 23 of the drive device 10 and can be effectively regenerated as pump power of the hybrid drive device 10.

  In addition, since the solenoid valve 89 between the bucket and the boom is provided in the working fluid supply passage 48 for the boom cylinder, the solenoid valve 89 is opened to the one-way flow position, so that one main pump 17A to the bucket cylinder 8bkc The working fluid supply amount can be supplied to the boom cylinder 8bmc via the electromagnetic valve 89 and merged with the working fluid supply amount from the boom assist pump 84as, and in particular, the boom cylinder 8bmc via the left chamber of the electromagnetic valve 49 for direction control. By increasing the supply amount of the working fluid supplied to the head side, the boom-up operation by the boom cylinder 8bmc can be speeded up and workability can be improved, and by closing the solenoid valve 89, the bucket cylinder 8bkc High pressure can be secured.

  Furthermore, the stick-boom solenoid valve 72 is provided in the circuit-to-circuit communication path 71 between the stick and boom that connects the working fluid supply path 61 for the stick cylinder and the head side of the boom cylinder 8bmc. By controlling the solenoid valve 72 between them to the one-way flow position, the solenoid valve for direction control is merged with the working fluid supplied from the boom assist pump 84as after passing through the solenoid valve 89 from one main pump 17A In addition to the supply amount of the working fluid supplied to the head side of the boom cylinder 8bmc through the left chamber of 49, the working fluid passed through the electromagnetic valve 72 from the other main pump 17B to the head side of the boom cylinder 8bmc Since the boom up operation by the boom cylinder 8bmc can be speeded up, workability can be improved. On the other hand, by closing the electromagnetic valve 72, it is possible to secure the amount of working fluid supplied from the other main pump 17B to the stick cylinder 8stc and to increase the speed of the stick cylinder 8stc.

  In addition, since the electromagnetic valve 74 between the bucket and stick is provided in the circuit-to-circuit communication path 73 between the bucket and stick, the electromagnetic valve 74 is controlled to a one-way flow position and the electromagnetic valves 72 and 89 are closed. The working fluid supplied from one main pump 17A to the boom cylinder working fluid supply passage 48 is supplied to the stick cylinder working fluid supply passage 61 via the solenoid valve 74, and this working fluid is supplied from the other main pump 17B. The working fluid supplied to the supply passage 61 can be combined and supplied to the stick cylinder 8stc, and the speed of the stick cylinder 8stc can be increased, so that workability can be improved.

  On the other hand, by controlling the electromagnetic valve 74 to the cut-off position, the pressure can be controlled separately by separating the boom system, the bucket system, and the stick system. In particular, the generation of high pressure in the bucket cylinder 8bkc can be ensured.

  The boom control circuit 45 can be disconnected from the main pumps 17A and 17B by closing the solenoid valves 72 and 89 to the cutoff position.

  The combination of the switching states of the solenoid valves 72, 74, and 89 increases the degree of freedom of combination and makes the system configuration flexible. Further, the fuel efficiency of the engine 11 can be improved by the hybrid system.

  Next, another embodiment shown in FIG. 3 will be described. The working machine to which this embodiment is applied is the same as that shown in FIG.

  In the hybrid drive device 10 shown in FIG. 3, 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 is recovered from a boom motor / generator 87 driven by the energy regenerative motor 26 via a generator controller 27c such as a converter thereof. Electric power is stored in the battery 23.

  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. 3, 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 passage 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 and 17B to the fluid pressure actuators 2trL, 2trR, 8bmc, 8stc, and 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. Stick control circuit 46 for controlling the working fluid supplied from the main pumps 17A, 17B of the hybrid drive device 10 to the bucket cylinder 8bkc, and a bucket control circuit 47 for controlling the working fluid supplied to the bucket cylinder 8bkc It has.

  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 head side working fluid supply / discharge passage 51, an electromagnetic valve 53 functioning as a fall prevention valve is interposed, and when the boom is stopped, the solenoid valve 53 is controlled to be switched to the check valve position on the left side to lower the boom 8bm by its own weight. 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.

  In the boom cylinder working fluid supply passage 48 for supplying the working fluid from the main pumps 17A, 17B of the hybrid drive device 10 to the boom cylinder 8bmc, a boom assist pump 84as for assisting the flow rate of the working fluid is provided. It is connected via a supply passage 85.

  The energy regenerative motor 26 provided in one return passage 56 through which the return fluid discharged from the boom cylinder 8bmc passes is driven by the energy regenerative motor 26 to supply power to the battery 23 of the hybrid drive device 10. A boom motor / generator 87 is connected to the boom assist pump 84as via the clutch 88.The boom motor / generator 87 functions as a generator and functions as an electric motor by the electric power supplied from the capacitor 23. ing. The clutch 88 transmits power to the boom assist pump 84as from the boom motor / generator 87 that functions as an electric motor, and disconnects the boom motor / generator 87 that functions as a generator from the boom assist pump 84as.

  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 for the boom driven by this energy regenerative motor 26 Electric power is supplied to and stored in the battery 23 of the hybrid drive device 10 by the motor / generator 87.

  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 head side working fluid supply / discharge passage 51 of the boom cylinder 8bmc communicates with the return fluid passage 55, and the energy regenerative motor 26 is spared by the boom's own weight due to the return fluid discharged from the head side of the boom cylinder 8bmc. It is desirable to operate with

  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 includes an electromagnetic valve 67 that controls the direction and the flow rate of the working fluid supplied through the bucket cylinder working fluid supply passage 66 drawn from the solenoid valve 35 that operates as a straight traveling valve. The working fluid supply / discharge passages 68 and 69 of the valve 67 are communicated with the head side chamber and the rod side chamber of the bucket cylinder 8bkc.

  Between the stick cylinder working fluid supply passage 61 and the head side of the boom cylinder 8bmc, there is provided a circuit-to-circuit communication passage 71 between the stick and boom that communicates these, and a circuit-to-circuit communication passage 71 between the stick and boom. The stick-to-boom solenoid valve 72 is displaced between a position allowing the one-way flow from the stick cylinder working fluid supply passage 61 to the head side of the boom cylinder 8bmc and a position blocking the flow. Is provided.

  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 bucket and the stick which communicates between them. In the inter-communication passage 73, there is provided an electromagnetic valve 74 between the bucket and the stick that has a position that allows a one-way flow from the boom cylinder working fluid supply passage 48 to the stick cylinder 8stc and a position that blocks it. .

  In the boom cylinder working fluid supply passage 48, between the branch portion of the bucket cylinder working fluid supply passage 66 and the junction from the boom assist pump 84as, the working fluid to the bucket cylinder 8bkc is supplied to the boom cylinder 8bmc. An electromagnetic valve 89 between the bucket and the boom is provided which is displaced between a position where supply is possible as a one-way flow to the position and a position where flow is interrupted.

  A turning control circuit 91 is provided separately from the fluid pressure actuator control circuit 25. The turning control circuit 91 controls the working fluid supplied to the turning motor 4swh that drives the upper turning body 4 to turn through the turning speed reduction mechanism 4gr.

  This turning control circuit 91 is provided with a solenoid valve 94 as a directional control valve having a flow rate control function in the closed circuits 92 and 93 of the turning motor 4swh, and for turning to the closed circuits 92 and 93 via this solenoid valve 94. A pump / motor 95 is connected. The turning pump motor 95 functions as a pump that supplies the working fluid to the turning motor 4swh, and also functions as a fluid pressure motor by the working fluid discharged from the turning motor 4swh.

  The electromagnetic valve 94 has a throttle switching valve function that adjusts the opening degree between a neutral position that closes between the swing pump motor 95 and the swing motor 4swh and a fully open position for right rotation and left rotation.

  A turning electric motor / generator 96 is connected to the turning pump / motor 95. The turning electric motor / generator 96 is connected to a turning electric motor / generator controller 96c such as an inverter, and the turning electric motor / generator controller 96c is connected to the capacitor 23 of the hybrid drive device 10. .

  The turning electric motor / generator 96 functions as a generator that is driven by a turning pump motor 95 that functions as a fluid pressure motor during turning braking of the upper turning body 4 and supplies electric power to the capacitor 23 of the hybrid drive device 10. At the same time, it functions as an electric motor that drives the turning pump motor 95 as a pump by the electric power supplied from the capacitor 23.

  That is, the battery 23 stores the electric power supplied from the turning electric motor / generator 96 functioning as the generator, and supplies the electric power to the turning electric motor / generator 96 functioning as the electric motor.

  An external communication passage 97 for supplying a working fluid to the lower traveling body 2 and the fluid pressure actuators 2trL, 2trR, 8bmc, 8stc, and 8bkc of the lower traveling body 2 and the work device 8 from the piping between the swing pump / motor 95 and the solenoid valve 94 Has been withdrawn.

  In this extraneous communication passage 97, the flow is cut off from the one-way flow position that enables supply of working fluid to the lower traveling body 2 and the fluid pressure actuators 2trL, 2trR, 8bmc, 8stc, 8bkc of the work device 8. A communication passage solenoid valve 98 whose opening degree is adjusted between the positions is provided.

  A working fluid replenishment pump 99 as a working fluid replenishing means for replenishing the working fluid is connected to a pipe between the turning pump motor 95 and the electromagnetic valve 94.

  Between the boom assist working fluid supply passage 85 of the boom assist pump 84as and the discharge passage 31 of the one main pump 17A, an inter-pump communication passage 101 that connects these passages is provided. This inter-pump communication passage 101 Among them, there is provided an electromagnetic valve 102 between the pumps that has a position that allows a one-way flow from the boom assist working fluid supply passage 85 of the boom assist pump 84as to the discharge passage 31 of the main pump 17A and a position that blocks it. It has been.

  The solenoid valves 53, 54, 65, 72, 74, 89, 98, and 102 are switching valves having a flow rate adjusting function incorporating a check valve.

  Various solenoid valves 33, 34, 35, 43, 44, 49, 53, 54, 58, 59, 62, 65, 67, 72, 74, 89, 94, 98, 102 are proportionally controlled by a controller (not shown) A solenoid and a return spring (not shown) are provided, respectively, and 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 embodiment shown in FIG. 3 will be described.

  When the upper swing body 4 is driven to swing relative to the lower traveling body 2 of the work machine 1, the electromagnetic valve 94 is controlled to the right or left direction control position and the electric power from the battery 23 of the hybrid drive device 10 is controlled. The swivel pump / motor 95 is actuated by the working fluid pressure generated by the swivel pump / motor 95 driven by the swivel motor / generator 96, and the upper swing body 4 is swung independently only by the swivel system. At the time of braking which can be driven and the upper swing body 4 is stopped, the communication passage electromagnetic valve 98 is closed, and the swing motor 4swh rotating by the inertial motion of the upper swing body 4 is driven by the working fluid discharged as a pump. 95 is operated as a fluid pressure motor load, and the turning electric motor / generator 96 is driven as a generator. Therefore, the inertial kinetic energy of the upper swing body 4 is converted into electric energy, and the upper swing body 4 is turned. Electric power can be efficiently collected in the battery 23 of the hybrid drive device 10 while braking the movement.

  On the other hand, when the swing motor 4swh does not require a large amount of working fluid, the solenoid valve 94 is moved closer to the neutral position, and the connecting passage solenoid valve 98 is moved closer to the one-way flow position to operate as a motor. The swiveling pump / motor 95 is driven as a pump by 96, and the swiveling pump / motor 95 is supplied to the outside communication passage 97 via the communication passage solenoid valve 98 while being refilled with the working fluid by the working fluid replenishment pump 99. The working fluid can be directly supplied to the lower traveling body 2 that needs the working fluid and the fluid pressure actuator control circuit 25 of the work device 8 that discharges the working fluid.

  That is, the external communication passage 97 is connected to the discharge passage 32 of the main pump 17B that supplies the working fluid to the boom cylinder 8bmc, the stick cylinder 8stc, and the travel motors 2trL and 2trR. Sufficient working fluid can be supplied from the main pumps 17A and 17B and the turning pump motor 95 functioning as a pump. Further, the main pumps 17A and 17B can be reduced in size by driving the turning pump / motor 95 as a pump.

  The fluid pressure actuator control circuit 25 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, the boom cylinder 8bmc, the stick cylinder 8stc, and the bucket cylinder 8bkc. By disconnecting 88, power is efficiently input from the energy regenerative motor 26 operated by the return fluid discharged from the boom cylinder 8bmc to the boom motor / generator 87 in the no-load state. It can be stored in the battery 23 of the hybrid drive device 10, and the energy of the return fluid discharged from the boom cylinder 8bmc can be effectively regenerated.

  In particular, when the boom 8bm of the work device 8 falls by its own weight, the energy of the return fluid discharged from the head side of the boom cylinder 8bmc is absorbed by the boom electric motor / generator 87 from the energy regenerative motor 26 and hybrid type. It can be stored in the battery 23 of the driving device 10.

  When the clutch 88 is connected, the boom assist pump 84as is driven by the boom motor / generator 87 that functions as an electric motor by the electric power from the battery 23 of the hybrid drive apparatus 10, and the boom assist pump 84as Since the working fluid can be supplied to the cylinder 8bmc, the working fluid can be supplied to the boom cylinder 8bmc from the boom assist pump 84as in addition to the main pumps 17A and 17B and the turning pump motor 95 functioning as a pump. A large amount of working fluid can be supplied from the pump, and the workability can be further improved by further increasing the speed of the boom-up operation.

  Further, the return fluid discharged from the boom cylinder 8bmc to the return fluid passage 55 is divided into one return passage 56 and the other return passage 57, and the divided flow ratio is controlled by the flow ratio control valves 58 and 59. The energy regenerative motor 26 is operated by one return fluid whose flow rate is controlled by the flow ratio control valves 58 and 59, and the boom motor / generator 87 is driven by the energy regenerative motor 26. Since the electric power is supplied to the storage battery 23, it is possible to prevent the occurrence of shock by gradually increasing the flow rate ratio diverted to the energy regenerative motor 26 from the time when the return fluid from the boom cylinder 8bmc is generated. By suppressing the sudden load fluctuation of 8bmc, 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.

  The flow ratio control valves 58, 59 can be installed with one solenoid valve 58 and the other solenoid valve 59 separately at any place in one return passage 56 and the other return passage 57, respectively. It is possible to freely control the flow rate ratio and flow rate of the return fluid flowing to the energy regeneration motor 26 side by individually controlling the opening degrees of the passage 56 and the other return passage 57 without being related to each other.

  In addition, since the solenoid valve 89 between the bucket and the boom is provided in the working fluid supply passage 48 for the boom cylinder, the solenoid valve 89 is opened to the one-way flow position, so that one main pump 17A to the bucket cylinder 8bkc The working fluid supply amount can be supplied to the boom cylinder 8bmc via the electromagnetic valve 89 and merged with the working fluid supply amount from the boom assist pump 84as, and in particular, the boom cylinder 8bmc via the left chamber of the electromagnetic valve 49 for direction control. By increasing the supply amount of the working fluid supplied to the head side, the boom-up operation by the boom cylinder 8bmc can be speeded up and workability can be improved, and by closing the solenoid valve 89, the bucket cylinder 8bkc High pressure can be secured.

  Furthermore, the stick-boom solenoid valve 72 is provided in the circuit-to-circuit communication path 71 between the stick and boom that connects the working fluid supply path 61 for the stick cylinder and the head side of the boom cylinder 8bmc. By controlling the solenoid valve 72 between them to the one-way flow position, the solenoid valve for direction control is merged with the working fluid supplied from the boom assist pump 84as after passing through the solenoid valve 89 from one main pump 17A In addition to the supply amount of the working fluid supplied to the head side of the boom cylinder 8bmc through the left chamber of 49, the working fluid passed through the electromagnetic valve 72 from the other main pump 17B to the head side of the boom cylinder 8bmc Since the boom up operation by the boom cylinder 8bmc can be speeded up, workability can be improved. On the other hand, by closing the electromagnetic valve 72, it is possible to secure the amount of working fluid supplied from the other main pump 17B to the stick cylinder 8stc and to increase the speed of the stick cylinder 8stc.

  In addition, since the electromagnetic valve 74 between the bucket and the stick is provided in the circuit-to-circuit communication path 73 between the bucket and the stick, the electromagnetic valve 74 is opened to the one-way flow position and the electromagnetic valves 72 and 89 are closed. The working fluid supplied from one main pump 17A to the boom cylinder 8bmc is merged with the working fluid supplied from the other main pump 17B to the stick cylinder 8stc, so that the speed of the stick cylinder 8stc can be increased and the bucket stick By closing the electromagnetic valve 74 and opening the electromagnetic valves 72 and 89, the working fluid supplied from the other main pump 17B to the stick cylinder 8stc is supplied from the main pump 17A to the boom cylinder working fluid supply passage 48, By joining the working fluid supplied to the head side of the boom cylinder 8bmc via the left chamber of the solenoid valve 89 and solenoid valve 49, the boom-up operation can be accelerated. It is possible to improve the work of.

  In addition, when the bucket-stick electromagnetic valve 74 is controlled to the shut-off 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, and the pressure Can be controlled separately. In particular, by closing the electromagnetic valve 89 together with the electromagnetic valve 74, a high pressure in the bucket cylinder 8bkc can be secured.

  In addition, since the inter-pump solenoid valve 102 is provided in the inter-pump communication passage 101, when the boom-up flow rate is not required, the solenoid valve 102 is opened to reduce the working fluid discharge amount from the boom assist pump 84as. The working fluid supply amount from one main pump 17A can be merged, so that workability can be improved, and by closing the electromagnetic valve 102, the working fluid supply amount to the boom cylinder 8bmc can be secured.

  In addition to the solenoid valve 72 between the stick and boom, the solenoid valve 74 between the bucket and stick, the solenoid valve 89 between the bucket and boom, and the solenoid valve 102 between the pumps, the communication passage solenoid valve 98 is opened and closed. Thus, the degree of freedom of combination between the circuits that replenish the working fluid is increased, and various operation pattern requirements can be easily met.

  The boom control circuit 45 can be completely disconnected from the main pumps 17A and 17B by closing the solenoid valves 72, 89, and 102 to the shut-off position.

  As described above, the combination of the switching states of the solenoid valves 72, 74, 89, 98, and 102 increases the degree of freedom of the combination and makes the system configuration flexible. Further, the fuel efficiency of the engine 11 can be improved by the hybrid system.

It is a circuit diagram showing one embodiment of a fluid pressure circuit of a work machine concerning the present invention. It is a side view of the working machine to which fluid pressure same as the above is applied. It is a circuit diagram which shows other embodiment of a fluid pressure circuit same as the above.

Explanation of symbols

1 Working machine 8 Working device
8bm boom
8st stick
8bk bucket
8bmc boom cylinder
8stc stick cylinder
8bkc bucket cylinder
17A, 17B main pump
22 Electric generator
23 Battery
26 Energy regeneration motor
48 Working fluid supply passage for boom cylinder
61 Working fluid supply passage for stick cylinder
66 Working fluid supply passage for bucket cylinder
71 Communication path between the stick and boom
72 Solenoid valve between stick and boom
84as boom assist pump
88 clutch
89 Solenoid valve between bucket and boom

Claims (2)

A working machine equipped with a working device in which a boom rotated by a boom cylinder that receives supply of working fluid from a plurality of main pumps, a stick rotated by a stick cylinder, and a bucket rotated by a bucket cylinder are sequentially connected. A fluid pressure circuit,
A working fluid supply passage for a boom cylinder for supplying working fluid from one main pump to the boom cylinder;
A working fluid supply passage for the bucket cylinder that is branched from the working fluid supply passage for the boom cylinder and supplies the working fluid to the bucket cylinder;
A working fluid supply passage for a stick cylinder that supplies working fluid from another main pump to the stick cylinder;
A boom assist pump for supplying the working fluid to the working fluid supply passage for the boom cylinder together with the one main pump;
A working fluid supply passage for the boom cylinder, which is provided between the branching portion of the working fluid supply passage for the bucket cylinder and the junction from the boom assist pump, and serves as a one-way flow to the boom cylinder. A solenoid valve between the bucket and the boom that is displaced between a position where supply is possible and a position where flow is interrupted;
A circuit-to-circuit communication path between the stick and the boom that is provided so as to communicate with the head side of the boom cylinder from the working fluid supply path for the stick cylinder;
The stick provided in the circuit communication path between the stick and the boom is displaced between a position where the working fluid to the stick cylinder can be supplied as a one-way flow to the head side of the boom cylinder and a position where the flow is blocked. -A hydraulic pressure circuit for a work machine, comprising a solenoid valve between the booms. An energy regenerative motor that is activated by the energy of the return fluid discharged from the boom cylinder;
An electric motor / generator functioning as a generator that is driven by the energy regeneration motor and supplies electric power to the electric storage device, and functions as an electric motor by electric power supplied from the electric storage device;
When the motor / generator functions as an electric motor, the motor / generator transmits power to the boom assist pump. The fluid pressure circuit of the working machine according to claim 1, wherein

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