JP2017125537A - Control system for hybrid working machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact control system for a hybrid working machine.SOLUTION: A control system 100 for a hybrid working machine comprises: fluid supply sources MP1, MP2, and AP for supplying a working fluid to a boom cylinder BC; a regeneration unit RU for regenerating an energy of the working fluid which is discharged from a piston-side chamber 25; a boom changeover valve 17 having an elongated position 17d and a contracted position 17e; and a boom two-speed changeover valve 6 having a speed increasing position 6d in which a speed increase flow passage 6f for introducing the working fluid to the piston-side chamber 25 is opened when the boom changeover valve 17 is in the elongated position 17d, and a regeneration reproducing position 6e in which a regeneration flow passage 6g for making the piston-side chamber 25 and a regeneration motor M communicate with each other, and a reproduction flow passage 6h for making the piston-side chamber 25 and a rod-side chamber 30 communicate with each other are opened when the boom changeover valve 17 is in the contracted position 17e.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a control system for a hybrid work machine.

  2. Description of the Related Art Conventionally, there is known a hybrid work machine that regenerates energy by rotating a hydraulic motor using hydraulic oil guided from an actuator.

  Patent Document 1 discloses a hybrid work machine including a boom cylinder that rotates a boom up and down. In this hybrid work machine, the hydraulic motor is rotated using hydraulic oil returned from the boom cylinder when the boom is lowered, and the generator is driven by the rotational torque of the hydraulic motor.

  This hybrid work machine includes a regenerative flow rate control valve that controls the flow rate of hydraulic fluid guided from the piston side chamber of the boom cylinder to the hydraulic motor, and a regenerative flow rate that controls the flow rate of hydraulic fluid guided from the piston side chamber of the boom cylinder to the rod side chamber. And a control valve. By controlling the opening of the regenerative flow control valve and the opening of the regeneration flow control valve, the energy regenerated in the generator and the lowering speed of the boom are adjusted.

JP 2011-179541 A

  However, in the hybrid working machine described in Patent Document 1, the regenerative flow control valve and the regeneration flow control valve are separately installed in the control system. In order to incorporate these control valves in the system, piping for connecting each control valve and each element is necessary, and it is necessary to secure a space in which each control valve is arranged. As a result, the cost of manufacturing the system increases, and the entire system may be increased in size.

  The present invention has been made in view of the above problems, and an object of the present invention is to make the control system of a hybrid work machine compact and to reduce the manufacturing cost.

  According to a first aspect of the present invention, a control system for a hybrid work machine has a first switching valve having an extended position for extending the fluid pressure cylinder and a contracted position for contracting the fluid pressure cylinder, and the first switching valve is in the extended position. A speed increasing position where the speed increasing flow path for guiding the working fluid supplied from the fluid supply source to the load side pressure chamber is opened, and a load side pressure chamber and a regenerative motor when the first switching valve is in the contracted position. And a regenerative regeneration position at which a regeneration passage communicating the load side pressure chamber and the anti-load side pressure chamber is opened. .

  In the first invention, the second switching valve has a position where acceleration control is performed to increase the operating speed of the fluid pressure cylinder by guiding the working fluid to the load side pressure chamber when the fluid pressure cylinder is extended. And a position where regeneration control for communicating the load side pressure chamber and the regeneration motor and regeneration control for communicating the load side pressure chamber and the anti-load side pressure chamber are performed. That is, the function as the regeneration control valve and the function as the regeneration control valve are integrated into the second switching valve that functions as the speed increase control valve. As described above, since a plurality of functions are integrated in one switching valve, piping for connecting each control valve and each element is not necessary as compared with the case where control valves having the respective functions are separately installed. In addition, it is not necessary to secure a space in which each control valve is arranged.

  According to a second aspect of the present invention, a control system for a hybrid work machine connects a connection passage connecting the first switching valve and the second switching valve, a second switching valve and the load side pressure chamber, and connects through the second switching valve. A load-side passage that can communicate with the passage, a communication passage that connects the connection passage and the load-side passage, and a check valve that is provided in the communication passage and allows only the flow of working fluid from the connection passage toward the load-side passage; When the first switching valve is switched to the extended position when the second switching valve is in the acceleration position or the neutral position, the operation is supplied from the fluid pressure source to the load side pressure chamber through the first switching valve. The fluid is guided to the load side passage through the connection passage and the second switching valve, and is guided to the load side passage through the connection passage and the check valve.

  In the second invention, since the connection passage communicates with the load side passage through the second switching valve, the working fluid discharged from the fluid supply source is the first switching valve, the connection passage, the second switching valve, and the load side. It is led to the load side pressure chamber through the passage. The working fluid discharged from the fluid supply source is also supplied from the connection passage to the load side passage through the communication passage without passing through the second switching valve. Thus, the working fluid is guided to the load side pressure chamber through the two paths. For this reason, the flow rate of the working fluid supplied to the load side pressure chamber is ensured, and the responsiveness of the fluid pressure cylinder can be improved. In addition, since the working fluid can be guided to the load side pressure chamber without going through the second switching valve having a large flow path resistance, the pressure loss when the working fluid is supplied to the load side pressure chamber is reduced. Can be reduced.

  According to a third aspect of the present invention, a control system for a hybrid work machine connects a connection passage connecting the first switching valve and the second switching valve, a second switching valve and the load side pressure chamber, and is connected through the second switching valve. A load side passage capable of communicating with the passage, and the second switching valve further includes a communication flow path that connects the load side passage that is opened when in the neutral position and the connection passage. The area that is opened is gradually reduced from the neutral position to the regenerative regeneration position.

  In the third invention, the area where the communication channel is opened gradually decreases from the neutral position to the regenerative regeneration position. For this reason, the flow of the working fluid guided from the load side passage to the connection passage is prevented from changing suddenly, and the fluid pressure cylinder can be operated smoothly.

  The fourth invention is characterized in that the communication flow path is closed when the second switching valve is in the regeneration regeneration position.

  In 4th invention, the communication flow path which connects a load side channel | path and a connection channel | path is obstruct | occluded when a 2nd switching valve displaces to a regeneration regeneration position. For this reason, all the working fluid discharged | emitted from a load side pressure chamber is guide | induced to either an anti-load side pressure chamber or a regeneration motor. Therefore, it is possible to effectively use the energy of all the discharged working fluid.

  According to a fifth aspect of the present invention, at least one of an area where the regeneration channel is opened and an area where the regeneration channel is opened gradually changes from the neutral position to the regeneration position.

  In the fifth invention, at least one of the area where the regeneration flow path is opened and the area where the regeneration flow path is opened gradually changes according to the displacement of the second switching valve which is displaced from the neutral position to the regeneration regeneration position. To do. In this way, by changing at least one of the area where the regenerative flow path is opened and the area where the regenerative flow path is opened according to the amount of displacement of the second switching valve, the antiload of the working fluid guided to the regenerative motor is changed. The distribution with the flow rate of the working fluid guided to the side pressure chamber can be changed.

  In the present invention, the control system of the hybrid work machine can be made compact and the manufacturing cost can be reduced.

It is a circuit diagram which shows the control system of the hybrid working machine which concerns on embodiment of this invention. It is a graph which shows the change of the opening degree of the communication flow path with respect to the position of the switching valve for boom 2nd speed. It is a graph which shows the change of the opening degree of the regeneration flow path or the regeneration flow path with respect to the position of the boom second speed switching valve. It is a graph which shows an example of the change of the opening degree of the regeneration flow path and the regeneration flow path with respect to the position of the boom second speed switching valve.

  Hereinafter, a control system for a hybrid work machine according to an embodiment of the present invention will be described with reference to the drawings.

  In the following embodiment, a case where the hybrid working machine is a hydraulic excavator will be described. In the following embodiments, the load is a boom of a hydraulic excavator, the fluid pressure cylinder is a boom cylinder BC for raising and lowering the boom, and hydraulic fluid is used as the working fluid.

  As shown in FIG. 1, the control system 100 for a hybrid work machine includes a variable capacity type first main pump MP1 and a variable capacity type first pump as a fluid supply source that pressurizes and supplies hydraulic oil stored in a tank T. A two-main pump MP2 and a variable displacement assist pump AP are provided.

  The discharge port of the first main pump MP1 is connected to the first circuit system via the first supply switching valve V1. The discharge port of the second main pump MP2 is connected to the second circuit system via the second supply switching valve V2. The discharge port of the assist pump AP can be merged with the discharge port of the first main pump MP1 via the first supply switching valve V1, and is also connected to the discharge port of the second main pump MP2 via the second supply switching valve V2. Can join.

  The first supply switching valve V1 is a 4-port 2-position spool type switching valve. The first supply switching valve V1 is provided with a pilot chamber facing one end of the spool, and the other end of the spool is supported by a spring. When the pilot pressure is not supplied to the pilot chamber, the first supply switching valve V1 is held at the normal position by the urging force of the spring (the state shown in FIG. 1).

  In a state where the first supply switching valve V1 is held at the normal position, the first supply pump V1 supplies the discharge oil of the first main pump MP1 to the first circuit system, and the discharge oil of the assist pump AP passes through the check valve. It merges with the discharge port of the main pump MP1.

  When the first supply switching valve V1 is switched to the switching position (right side position in FIG. 1) by the pilot pressure in the pilot chamber, the merge of the discharge oil of the assist pump AP to the discharge port of the first main pump MP1 is blocked. . At this time, the supply of the discharge oil of the first main pump MP1 to the first circuit system is maintained.

  The second supply switching valve V2 is a 6-port 3-position spool type switching valve. The second supply switching valve V2 is provided with pilot chambers facing both ends of the spool. The spool is supported in a neutral state by a pair of centering springs provided at both ends. The second supply switching valve V2 is normally held at the normal position by the spring force of the centering spring (the state shown in FIG. 1).

  The second supply switching valve V2 supplies the discharge oil of the second main pump MP2 to the second circuit system and discharges the discharge oil of the assist pump AP to the second main pump MP2 in a state where it is held at the normal position. Join the port.

  When the second supply switching valve V2 is switched to the first switching position (right position in FIG. 1) by the pilot pressure in one pilot chamber, the discharge oil of the assist pump AP joins the discharge port of the second main pump MP2. Is cut off. At this time, the supply of the discharge oil of the second main pump MP2 to the second circuit supply system is maintained.

  When the second supply switching valve V2 is switched to the second switching position (left side position in FIG. 1) by the pilot pressure in the other pilot chamber, the discharge oil of the assist pump AP joins the discharge port of the second main pump MP2. And the supply of the oil discharged from the second main pump MP2 to the second circuit supply system are both cut off.

  At this time, the discharge oil of the second main pump MP2 is supplied to a regenerative motor M, which will be described later, and rotates the regenerative motor M. In the normal position and the first switching position, the supply of the oil discharged from the second main pump MP2 to the hydraulic motor M is cut off.

  A pilot pressure is supplied to the pilot chamber of the first supply switching valve V1 from the pilot hydraulic power source PP through the electromagnetic valve 1. The solenoid valve 1 shuts off the pilot chamber from the pilot hydraulic power source PP at the normal position where the solenoid is not excited (the state shown in FIG. 1). When the solenoid is excited, the solenoid valve 1 is switched to a communication position (lower position in FIG. 1) for supplying the discharge oil of the pilot hydraulic power source PP to the pilot chamber.

  One pilot chamber of the second supply switching valve V2 is connected to the pilot hydraulic pressure source PP via the electromagnetic valve 2a. The other pilot chamber of the second supply switching valve V2 is connected to the pilot hydraulic pressure source PP through the electromagnetic valve 2b. The solenoid valve 2a and the solenoid valve 2b shut off the pilot chamber from the pilot hydraulic power source PP in the normal position where the solenoid is not excited (state shown in FIG. 1). The solenoid valve 2a and the solenoid valve 2b are switched to a communication position for supplying the discharge oil of the pilot hydraulic source PP to the pilot chamber when the solenoid is excited.

  The solenoids of the solenoid valve 1, the solenoid valve 2a, and the solenoid valve 2b are connected to the controller C.

  The controller C includes a microcomputer having a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface). The controller C may be composed of a single microcomputer or a plurality of microcomputers.

  The controller C excites or de-energizes each solenoid of the solenoid valve 1, the solenoid valve 2a, and the solenoid valve 2b in accordance with an input signal from the operator of the hybrid work machine.

  The first main pump MP1 and the second main pump MP2 are rotationally driven by the engine E. The engine E is provided with a generator 3 that generates power using surplus torque. The electric power generated by the generator 3 is charged to the battery 37 via the battery charger 38. The battery charger 38 can charge the battery 37 even when a normal household power supply 39 is connected.

  The first circuit system connected to the first main pump MP1 includes, from the upstream side, a switching valve 4 for controlling the turning motor 4, a switching valve for controlling the arm cylinder 5, and a second switching valve for controlling the boom cylinder BC. There are provided a boom second speed switching valve 6, a switching valve 7 for controlling the auxiliary attachment, and a switching valve 8 for controlling the left traveling motor. These switching valves 4 to 8 are connected to each other through a neutral passage 9 and a parallel passage 10, and are connected to a first main pump MP1 through a first supply switching valve V1. A specific configuration of the boom second speed switching valve 6 will be described later.

  A throttle 11 for pilot pressure control for generating pilot pressure is provided downstream of the switching valve 8 for the left travel motor in the neutral passage 9. The throttle 11 generates a high pilot pressure on the upstream side when the flow rate is high, and generates a low pilot pressure on the upstream side when the flow rate is low.

  Specifically, the neutral passage 9 restricts all or part of the hydraulic oil supplied from the first main pump MP1 to the first circuit system when the switching valves 4 to 8 are in the neutral position or in the vicinity of the neutral position. Through the tank T. At this time, since the flow rate of the hydraulic oil that passes through the throttle 11 increases, a high pilot pressure is generated.

  On the other hand, in the neutral passage 9, when the switching valves 4 to 8 are switched to the full stroke state, the fluid does not flow. In this case, since the flow rate of the hydraulic oil flowing through the throttle 11 is eliminated, the pilot pressure becomes zero. Depending on the operation amount of the switching valves 4 to 8, part of the hydraulic oil is led to the actuator, and the rest is led to the tank T from the neutral passage 9. Therefore, the throttle 11 generates a pilot pressure corresponding to the flow rate of the hydraulic oil flowing through the neutral passage 9. Thus, the throttle 11 generates a pilot pressure corresponding to the operation amount of the switching valves 4 to 8 located on the upstream side.

  A pilot passage 12 is connected between the switching valve 8 and the throttle 11 in the neutral passage 9. The pilot passage 12 is connected to a regulator 14 that controls the tilt angle of the swash plate of the first main pump MP1 via an electromagnetic switching valve 13.

  The regulator 14 controls the tilt angle of the swash plate of the first main pump MP1 to be proportional to the pilot pressure (the proportionality constant is a negative number), and the hydraulic oil discharge amount per one rotation of the first main pump MP1. Set.

  The electromagnetic switching valve 13 is a switching valve that connects one of the pilot pressure source 12 and the pilot hydraulic pressure source PP to the regulator 14 in accordance with its position. In the normal position, the electromagnetic switching valve 13 supplies the pressure in the pilot passage 12 to the regulator 14 as the pilot pressure (state shown in FIG. 1). The electromagnetic switching valve 13 is switched to a switching position (lower position in FIG. 1) when supplied with an exciting current, and supplies the pressure of the pilot hydraulic power source PP to the regulator 14 as a pilot pressure.

  The solenoid of the electromagnetic switching valve 13 is connected to the controller C. In response to an input signal from the operator of the hybrid work machine, the controller C supplies an excitation current to the electromagnetic switching valve 13 to switch to the switching position. On the other hand, the controller C de-energizes the solenoid and holds the electromagnetic switching valve 13 in the normal position unless a signal is input by the operator.

  When the electromagnetic switching valve 13 is in the normal position, when the switching valves 4 to 8 are switched to the full stroke and the flow of the neutral passage 9 disappears, and the pilot pressure in the pilot passage 12 becomes zero, the first main pump MP1 is inclined. The turning angle is maximum. At this time, the hydraulic oil discharge amount per rotation of the first main pump MP1 is maximized.

  On the other hand, the electromagnetic switching valve 13 is used when all of the switching valves 4 to 8 are maintained in the normal position, for example, during warm-up operation, that is, a swing motor, an arm cylinder, a boom cylinder BC, a spare attachment, When the left travel motor is not in operation, it is switched to the switching position. When the electromagnetic switching valve 13 is in the switching position, the pressure of the pilot hydraulic power source PP is supplied to the regulator 14 as pilot pressure without being reduced. For this reason, the tilt angle of the first main pump MP1 is minimized, and the hydraulic oil discharge amount per rotation of the first main pump MP1 is minimized. Thus, since the discharge amount of 1st main pump MP1 reduces rather than usual because electromagnetic switching valve 13 is switched to a switching position, consumption of useless fuel can be suppressed.

  The pilot passage 12 is provided with a first pressure sensor 42 that detects the pressure of the pilot passage 12. The pressure detected by the first pressure sensor 42 is output to the controller C.

  The second circuit system connected to the second main pump MP2 includes, from the upstream side, a switching valve 15 that controls the right traveling motor, a switching valve 16 that controls the bucket cylinder, and a first switching valve that controls the boom cylinder BC. A boom switching valve 17 and an arm second speed switching valve 18 for controlling the arm cylinder are provided. These switching valves 15 to 18 are connected to each other via a neutral passage 19, and are connected to the second main pump MP2 via a second supply switching valve V2. The switching valve 16 and the boom switching valve 17 are connected to each other via the parallel passage 20. A specific configuration of the boom switching valve 17 will be described later.

  A throttle 21 for pilot pressure control for generating a pilot pressure is provided on the downstream side of the switching valve 18 for the second-arm arm in the neutral passage 19. The throttle 21 supplies the upstream pressure as a pilot pressure to the regulator 23 of the second main pump MP2 via the pilot passage 22. Since the diaphragm 21 functions in the same manner as the diaphragm 11, a detailed description thereof is omitted here.

  The regulator 23 controls the inclination angle of the swash plate of the second main pump MP2 to be proportional to the pilot pressure (the proportionality constant is a negative number), and the hydraulic oil discharge amount per one rotation of the second main pump MP2 is controlled. Set. For example, when the switching valves 15 to 18 are switched to the full stroke, the flow of the neutral passage 19 disappears and the pilot pressure in the pilot passage 22 becomes zero, the tilt angle of the second main pump MP2 becomes maximum. At this time, the hydraulic oil discharge amount per rotation of the second main pump MP2 is maximized.

  The pilot passage 22 is provided with a second pressure sensor 43 that detects the pressure of the pilot passage 22. The pressure detected by the second pressure sensor 43 is output to the controller C.

  Next, the boom cylinder BC as a fluid pressure cylinder from which hydraulic fluid having energy is discharged when contracted, the boom switching valve 17 for switching the operation of the boom cylinder BC, and the boom second speed switching valve 6 will be described.

  The boom cylinder BC includes a piston that internally defines a piston-side chamber 25 as a load-side pressure chamber and a rod-side chamber 30 as an anti-load-side pressure chamber, and a piston rod that connects the piston and the boom. The boom cylinder BC extends by supplying hydraulic oil to the piston side chamber 25 to raise the boom, and contracts by discharging hydraulic oil from the piston side chamber 25 to lower the boom. The operation of the boom cylinder BC is controlled by the boom switching valve 17 and the boom second speed switching valve 6.

  The boom switching valve 17 is a 6-port 3-position spool type switching valve. The boom switching valve 17 is connected as an input port to a port connected to the neutral passage 19, a port connected to the parallel passage 20, and a discharge passage 31 connecting the boom switching valve 17 and the tank T. And a port. In addition, the boom switching valve 17 has, as output ports, a port connected to the connection passage 26 that connects the boom switching valve 17 and the boom second speed switching valve 6, and the boom switching valve 17 and the boom cylinder BC. It has a port connected to the anti-load side passage 29 connecting the rod side chamber 30 and a port connected to the neutral passage 19.

  The boom switching valve 17 is provided with pilot chambers 17a and 17b facing both ends of a spool (not shown). The spool is supported in a neutral state by the urging force of a pair of centering springs provided at both ends.

  The three positions of the boom switching valve 17 include an extension position 17d for extending the boom cylinder BC, a contraction position 17e for contracting the boom cylinder BC, and a stop position 17c for stopping the boom cylinder BC. These three positions are selected by the operation of the operator of the hybrid work machine.

  Specifically, when the boom operating lever (not shown) is operated by the operator in the direction to raise the boom, the pilot pressure is supplied to the pilot chamber 17a, and the boom switching valve 17 is moved to the extended position 17d (the right position in FIG. 1). ). On the other hand, when the boom operating lever is operated by the operator in the direction of lowering the boom, the pilot pressure is supplied to the pilot chamber 17b, and the boom switching valve 17 is switched to the contracted position 17e (left side position in FIG. 1). When the boom operating lever is operated by the operator to the position where the boom is stopped, that is, to the neutral position, the boom switching valve 17 is switched to the stop position 17c (position in FIG. 1) by the urging force of the centering spring.

  When the boom switching valve 17 is at the stop position 17c, the upstream neutral passage 19 and the downstream neutral passage 19 are in communication with each other, and the other ports are shut off. When the boom switching valve 17 is in the extended position 17d, the parallel passage 20 and the connection passage 26 are in communication with each other, and the anti-load side passage 29 and the discharge passage 31 are in communication with each other. 19 and the neutral passage 19 on the downstream side are cut off. When the boom switching valve 17 is in the contracted position 17e, the connection passage 26 and the discharge passage 31 are in communication with each other through the throttle, and the parallel passage 20 and the anti-load side passage 29 are in communication with each other. The neutral passage 19 and the downstream neutral passage 19 are blocked.

  The boom second speed switching valve 6 is an 8-port 3-position spool type switching valve. The boom second speed switching valve 6 has, as input ports, a port connected to the neutral passage 9, a port connected to the parallel passage 10, and a port connected to the branch passage 29 a branched from the anti-load side passage 29. And a port connected to a connection passage 26 that connects the boom second speed switching valve 6 and the boom switching valve 17. Further, the boom second speed switching valve 6 includes, as output ports, a port connected to the neutral passage 9, a port connected to the branch passage 26 a branched from the connection passage 26, and the boom second speed switching valve 6. A port connected to a regenerative passage 27 for connecting a regenerative motor M to be described later, and a port connected to a load side passage 24 for connecting the boom second speed switching valve 6 and the piston side chamber 25 of the boom cylinder BC. Have.

  The boom second speed switching valve 6 is provided with pilot chambers 6a and 6b facing both ends of a spool (not shown). The spool is supported in a neutral state by the urging force of a pair of centering springs provided at both ends. The pilot chamber 6 b is supplied with the pressure of the pilot hydraulic power source PP through the pilot passage 51. An electromagnetic proportional pressure reducing valve 52 capable of outputting a pilot pressure proportional to a command signal from the controller C is interposed in the pilot passage 51. When the solenoid is energized based on the command signal output from the controller C, the electromagnetic proportional pressure reducing valve 52 reduces the pilot pressure from the pilot hydraulic power source PP to obtain a pilot pressure corresponding to the command value. Supply to the passage 51.

  The boom second speed switching valve 6 has three positions: a speed increasing position 6d capable of communicating the first main pump MP1 with the piston side chamber 25 when the boom switching valve 17 is in the extended position 17d, and a speed increasing position 6d. When the boom switching valve 17 is in the contracted position 17e, the piston side chamber 25 and the rod side chamber 30 can communicate with each other, and the piston side chamber can be communicated with the neutral position 6c. 25 and a regenerative regeneration position 6e through which the regenerative motor M can communicate. These three positions are selected by the operation of the operator of the hybrid work machine and the command signal from the controller C.

  Specifically, when the operator operates the boom operating lever in the direction to raise the boom cylinder BC, the pilot pressure is supplied to the pilot chamber 6a, and when the boom operating lever is operated more than a predetermined amount, The switching valve 6 is switched to the acceleration position 6d (right side position in FIG. 1). On the other hand, when the boom operation lever is returned to the neutral state, the boom second speed switching valve 6 is returned to the neutral position 6c (position in FIG. 1) by the urging force of the centering spring. If the controller C determines that the energy can be regenerated by the regenerative unit RU described later when the boom switching valve 17 is at the contracted position 17e, the controller C sends a command signal to the electromagnetic proportional pressure reducing valve 52. Is output. The electromagnetic proportional pressure reducing valve 52 supplies pilot pressure corresponding to the command signal to the pilot chamber 6 b through the pilot passage 51. As a result, the boom second speed switching valve 6 is switched to the regenerative regeneration position 6e (left position in FIG. 1).

  When the boom second speed switching valve 6 is in the neutral position 6c, the upstream neutral passage 9 and the downstream neutral passage 9 are in communication with each other, and the connection passage 26 and the load side passage 24 are in communication with each other. And other ports are blocked. The spool of the boom second speed switching valve 6 is formed with a communication flow path 6i that allows the connection passage 26 and the load side passage 24 to communicate with each other, and the communication flow path 6i is opened at the neutral position 6c.

  When the boom second speed switching valve 6 is in the speed increasing position 6d, the parallel passage 10 and the branch passage 26a are in communication with each other, and the connection passage 26 and the load side passage 24 are in communication with each other. Is cut off. The spool of the boom second speed switching valve 6 is formed with a speed increasing flow path 6f that allows the parallel passage 10 and the branch path 26a to communicate with each other. The speed increasing flow path 6f is opened at the speed increasing position 6d. At the speed increasing position 6d, the communication channel 6i is also opened.

  When the boom second speed switching valve 6 is in the regenerative regeneration position 6e, the load side passage 24 and the branch passage 29a communicate with each other through the throttle and check valve, and the load side passage 24 and the regeneration passage 27 communicate with each other. It becomes the state. Further, the upstream neutral passage 9 and the downstream neutral passage 9 are communicated with each other, and the other ports are blocked. The spool of the boom second speed switching valve 6 is formed with a regenerative flow path 6g for communicating the load side passage 24 and the regenerative path 27 and a regeneration flow path 6h for communicating the load side path 24 and the branch passage 29a. The regenerative flow path 6g and the regenerative flow path 6h are opened at the regenerative regeneration position 6e.

  Further, as shown in FIG. 1, the connection passage 26 for connecting the boom switching valve 17 and the boom second speed switching valve 6 is connected to the boom second speed switching valve 6 and the piston side chamber 25 of the boom cylinder BC. The load side passage 24 is communicated with a communication passage 28. The communication passage 28 is provided with a check valve 32, and the check valve 32 blocks the flow of hydraulic oil from the load side passage 24 to the connection passage 26, and operates from the connection passage 26 to the load side passage 24. Only oil flow is allowed.

  Further, a lowering prevention valve 33 is provided in the load side passage 24 closer to the piston side chamber 25 than the position where the communication passage 28 is connected. The lowering prevention valve 33 is provided to prevent the boom cylinder BC from unintentionally contracting and lowering the boom. The lowering prevention valve 33 has a check valve and a pilot pressure chamber that opens the check valve. The pilot pressure supplied to the pilot chamber 17 b of the boom switching valve 17 is supplied to the pilot pressure chamber through the pilot passage 34.

  For this reason, when the pilot pressure is not supplied to the pilot pressure chamber of the lowering prevention valve 33, the inflow of hydraulic oil to the piston side chamber 25 is allowed, but the outflow of the hydraulic oil from the piston side chamber 25 is prevented from falling. Blocked by 33. On the other hand, when the pilot pressure is supplied to the pilot pressure chamber of the lowering prevention valve 33, that is, when the operation of lowering the boom is performed by the operator and the pilot pressure is supplied to the pilot chamber 17b, the lowering prevention valve 33 is. Is opened, and the hydraulic oil in the piston-side chamber 25 can flow out through the load-side passage 24.

  The boom switching valve 17 and the boom second speed switching valve 6 are arranged in a valve block (not shown) together with the other switching valves 4, 5, 7, 8, 15, 16, and 18. Further, the load side passage 24 connected to the boom second speed switching valve 6 is connected to the valve block at the first connection point CP1, and the boom second speed switching valve is located in the load side passage 24 more than the first connection point CP1. The portion on the 6 side is formed in the valve block. Similarly, a portion of the anti-load side passage 29 connected to the boom switching valve 17 that is closer to the boom switching valve 17 than the second connection point CP2 is formed in the valve block, and the boom second speed switching valve 6 is provided. A portion of the regenerative passage 27 connected to the boom second speed switching valve 6 side with respect to the third connection point CP3 is formed in the valve block.

  Thus, between the valve block and the boom cylinder BC and between the valve block and the regenerative motor M, control valves such as a regeneration control valve and a regenerative control valve are not arranged, and only piping exists. This eliminates the need for piping connecting each control valve and each element, and eliminates the need to secure a space in which each control valve is arranged. As a result, the cost for manufacturing the control system 100 for the hybrid work machine can be reduced, and the control system 100 for the hybrid work machine can be made compact.

  Further, since the switching valve is not provided on the pipe connecting the valve block and the boom cylinder BC, there is no change in the pipe volume due to switching of the switching valve. For this reason, the displacement of the boom cylinder BC generated due to the change in the volume of the piping when switching the switching valve is suppressed, and the response of the operation of the boom cylinder BC can be improved. In addition, since most of the flow paths can be formed in the valve block, the length of the flow paths can be shortened compared to the case where piping is used. As a result, the pressure loss when the hydraulic oil moves can be reduced.

  Next, the regenerative unit RU that recovers the energy of the hydraulic oil discharged from the piston side chamber 25 and performs energy regeneration will be described.

  The regenerative unit RU is rotated by the hydraulic oil discharged from the piston side chamber 25 of the boom cylinder BC to recover the energy of the hydraulic oil, and the rotating electric machine that is connected to the regenerative motor M and functions as a generator and an electric motor. 35, an inverter 36 that converts electric power generated by the rotating electrical machine 35 into direct current, and a battery 37 as a storage battery that stores the power generated by the rotating electrical machine 35.

  The regenerative motor M is a variable capacity motor that can adjust the tilt angle, and has a regulator 40 for controlling the tilt angle of the swash plate. The regulator 40 changes the tilt angle of the swash plate of the regenerative motor M in accordance with a signal from the controller C. The hydraulic oil discharged from the piston side chamber 25 is guided to the regenerative motor M through the regenerative passage 27, and the regenerative motor M is rotationally driven by the guided hydraulic oil.

  The regenerative motor M is connected so as to rotate coaxially with the rotating electrical machine 35 and the assist pump AP, and can drive the rotating electrical machine 35 and the assist pump AP. The regenerative motor M, the rotating electrical machine 35, and the assist pump AP may be directly connected or may be connected via a speed reducer.

  When the rotating electrical machine 35 is caused to function as a generator, the electric power generated by the rotating electrical machine 35 is charged to the battery 37 via the inverter 36. In this case, it is preferable to minimize the tilt angle of the swash plate of the assist pump AP so that the driving load of the assist pump AP does not act on the regenerative motor M.

  The battery 37 is connected to the controller C, and a signal indicating the charged amount of the battery 37 is input to the controller C. The controller C determines whether or not the battery 37 is in a chargeable state based on the input charged amount, and the number of rotations of the regenerative motor M and the rotating electrical machine 35 and the flow rate of hydraulic oil guided to the regenerative motor M. Control etc.

  When the rotating electrical machine 35 is caused to function as an electric motor, the assist pump AP can be rotationally driven by the output torque of the rotating electrical machine 35 driven by the power of the battery 37. At this time, the assist pump AP discharges hydraulic oil corresponding to the tilt angle of the swash plate. In this case, it is preferable to minimize the tilt angle of the swash plate of the regenerative motor M to reduce the rotational resistance and to minimize the output loss of the rotating electrical machine 35.

  The tilt angle of the swash plate of the assist pump AP is controlled by the regulator 41. The regulator 41 changes the tilt angle of the swash plate of the assist pump AP according to the signal from the controller C.

  The controller C determines whether or not assistance is required for the first main pump MP1 and the second main pump MP2 based on the pressure signals of the first pressure sensor 42 and the second pressure sensor 43, and assistance is required. If it is determined that there is, the tilt angle of the swash plate of the assist pump AP, the position of the first supply switching valve V1, and the position of the second supply switching valve V2 are appropriately controlled. As a result, the discharge oil of the assist pump AP is supplied to the discharge port side of the main pump that needs assistance.

  The assist pump AP can be rotated by the driving force of one or both of the regenerative motor M and the rotating electrical machine 35. For example, if the driving force of the regenerative motor M is large, the hydraulic oil can be discharged from the assist pump AP even when the regenerative motor M drives the rotating electrical machine 35 to generate power.

  Next, the flow of hydraulic oil when operating the boom in the control system 100 for a hybrid work machine having the above configuration will be specifically described.

  First, the case where a boom is raised is demonstrated.

  When the boom operating lever is operated by the operator in the direction to raise the boom, the pilot pressure is supplied to the pilot chamber 17a of the boom switching valve 17, and the boom switching valve 17 is switched to the extended position 17d. When the boom switching valve 17 is switched to the extended position 17d, the parallel passage 20 and the connection passage 26 are communicated, and the anti-load side passage 29 and the discharge passage 31 are communicated.

  Since the connection passage 26 communicates with the load side passage 24 through the boom second speed switching valve 6, the hydraulic fluid discharged from the second main pump MP2 is neutralized passage 19, parallel passage 20, boom switching valve 17, It is guided to the piston side chamber 25 of the boom cylinder BC through the connection passage 26, the boom second speed switching valve 6, the load side passage 24, and the lowering prevention valve 33.

  The connection passage 26 is communicated with the load side passage 24 through the communication passage 28 and the check valve 32. Since the check valve 32 allows the flow of hydraulic oil from the connection passage 26 toward the load side passage 24, the hydraulic oil discharged from the second main pump MP2 passes through the boom second speed switching valve 6. Instead, the load is also supplied from the connection passage 26 to the load side passage 24 through the communication passage 28.

  In this way, the hydraulic oil discharged from the second main pump MP2 is guided to the piston side chamber 25 through two paths. For this reason, the flow volume of the hydraulic fluid supplied to the piston side chamber 25 is ensured, and the responsiveness of the boom cylinder BC can be improved. Further, since the hydraulic oil can be guided to the piston side chamber 25 without going through the boom second speed switching valve 6 which is a spool valve having a relatively large flow path resistance, the hydraulic oil is supplied to the piston side chamber 25. It is possible to reduce the pressure loss when being performed.

  On the other hand, the rod side chamber 30 of the boom cylinder BC communicates with the tank T through the anti-load side passage 29, the boom switching valve 17 and the discharge passage 31. As a result, the hydraulic oil is supplied to the piston side chamber 25 and the hydraulic oil is discharged from the rod side chamber 30, whereby the boom cylinder BC is extended and the boom is raised.

  When the boom operating lever is operated in the direction of raising the boom, the pilot pressure is supplied to the pilot chamber 6a of the boom second speed switching valve 6 simultaneously with the pilot chamber 17a of the boom switching valve 17. When a pilot pressure of a predetermined amount or more is supplied to the pilot chamber 6a, the boom second speed switching valve 6 is switched to the speed increasing position 6d, and the branch passage 26a branched from the connection passage 26 and the parallel passage 10 are connected to the boom two. It communicates through the speed switching valve 6.

  For this reason, the hydraulic fluid discharged from the first main pump MP1 through the boom second speed switching valve 6 together with the hydraulic fluid discharged from the second main pump MP2 guided through the boom switching valve 17 into the connection passage 26. Led. As a result, the amount of hydraulic oil supplied to the piston side chamber 25 increases, and the speed at which the boom cylinder BC extends, that is, the boom raising speed is increased.

  Next, a case where the boom is lowered will be described.

  When the boom operating lever is operated by the operator in the direction of lowering the boom, the pilot pressure is supplied to the pilot chamber 17b of the boom switching valve 17, and the boom switching valve 17 is switched to the contracted position 17e. When the boom switching valve 17 is switched to the contracted position 17e, the parallel passage 20 and the anti-load side passage 29 are communicated, and the connection passage 26 and the discharge passage 31 are communicated.

  The connection passage 26 communicates with the load side passage 24 through the boom second speed switching valve 6, and the pilot pressure chamber of the lowering prevention valve 33 provided in the load side passage 24 is connected to the pilot chamber 17 b through the pilot passage 34. Since the supplied pilot pressure is supplied, the lowering prevention valve 33 is maintained in the opened state. For this reason, the piston side chamber 25 of the boom cylinder BC communicates with the tank T through the load side passage 24, the lowering prevention valve 33, the boom second speed switching valve 6, the connection passage 26, the boom switching valve 17 and the discharge passage 31. .

  On the other hand, the rod side chamber 30 of the boom cylinder BC is communicated with the second main pump MP2 through the anti-load side passage 29, the boom switching valve 17, the parallel passage 20, and the neutral passage 19. As a result, the hydraulic oil is supplied to the rod side chamber 30 and the hydraulic oil is discharged from the piston side chamber 25, whereby the boom cylinder BC contracts and the boom descends.

  When the boom is lowered, if the energy of the hydraulic oil discharged from the piston side chamber 25 can be regenerated, regenerative control is executed. The case where energy can be regenerated is a case where there is no abnormality in the control system 100, particularly the regenerative unit RU, and the battery 37 is not fully charged.

  Further, when lowering the boom, in order to increase the lowering speed of the boom, that is, the contraction speed of the boom cylinder BC, a part of the hydraulic oil discharged from the piston side chamber 25 is guided to the rod side chamber 30 as a regeneration flow rate. Playback control is performed.

  Hereinafter, regenerative control and regeneration control performed when the boom is lowered will be described.

  When it is determined by the controller C that the energy of the hydraulic oil discharged from the piston side chamber 25 can be regenerated, the controller C outputs a command signal to the electromagnetic proportional pressure reducing valve 52. The electromagnetic proportional pressure reducing valve 52 supplies pilot pressure corresponding to the command signal to the pilot chamber 6 b through the pilot passage 51. As a result, the boom second speed switching valve 6 is switched to the regenerative regeneration position 6e.

  When the boom second speed switching valve 6 is switched to the regenerative regeneration position 6e, the load side passage 24 is disconnected from the connection passage 26 and is in communication with the regeneration passage 27 and the branch passage 29a. Therefore, the hydraulic oil discharged from the piston side chamber 25 is guided to the regenerative motor M through the load side passage 24, the boom second speed switching valve 6 and the regenerative passage 27, not the tank T, and the load side passage 24, boom. The second speed switching valve 6, the branch passage 29 a and the anti-load side passage 29 are led to the rod side chamber 30.

  The hydraulic oil guided to the regenerative motor M rotates the regenerative motor M, and the rotational torque is converted into electric power by the rotating electrical machine 35. The electric power generated by the rotating electrical machine 35 is charged to the battery 37 via the inverter 36. In this way, the energy of the hydraulic oil discharged from the piston side chamber 25 is regenerated.

  On the other hand, the hydraulic oil guided to the rod side chamber 30 acts to contract the boom cylinder BC together with the hydraulic oil discharged from the second main pump MP2 guided to the rod side chamber 30 through the boom switching valve 17. Thus, by guiding a part of the hydraulic oil discharged from the piston side chamber 25 to the rod side chamber 30, the flow rate of the hydraulic oil supplied to the rod side chamber 30 increases and the boom cylinder BC contracts, that is, The lowering speed of the boom can be increased.

  The distribution of the flow rate of the hydraulic fluid guided to the regenerative motor M and the flow rate of the hydraulic fluid guided to the rod side chamber 30 is the opening cross-sectional area of the regenerative flow path 6g formed in the spool of the boom second speed switching valve 6. It is set by the ratio to the opening cross-sectional area of the regeneration channel 6h. That is, if the opening cross-sectional area of the regenerative flow path 6g is increased, the amount of power generated by the rotating electrical machine 35 increases, and if the opening cross-sectional area of the regeneration flow path 6h is increased, the lowering speed of the boom is increased.

  When the battery 37 is fully charged due to energy regeneration, or when an abnormality occurs in the regeneration unit RU, or when it is not necessary to increase the lowering speed of the boom, the controller C instructs the electromagnetic proportional pressure reducing valve 52 to Stop signal output. When the command signal to the electromagnetic proportional pressure reducing valve 52 is stopped, the pilot chamber 6b is communicated with the tank T, the boom second speed switching valve 6 is switched to the neutral position 6c, and the above-described regenerative control and regeneration control are stopped. Is done.

  Next, the case where a boom is stopped is demonstrated.

  When the boom operating lever is operated by the operator from the position where the boom is operated to the position where the boom is stopped, that is, the neutral position, the supply of pilot pressure to the boom switching valve 17 and the boom second speed switching valve 6 is stopped. . Therefore, the boom switching valve 17 is switched to the stop position 17c by the biasing force of the centering spring, and the boom second speed switching valve 6 is switched to the neutral position 6c by the biasing force of the centering spring. As described above, when the boom switching valve 17 is switched to the stop position 17c and the boom second speed switching valve 6 is switched to the neutral position 6c, the hydraulic oil is supplied to both the load side passage 24 and the anti-load side passage 29. Is not supplied, the operation of the boom cylinder BC is stopped, and the operation of the boom is also stopped.

  In addition, since the pilot pressure is not supplied to the pilot pressure chamber of the lowering prevention valve 33 provided in the load side passage 24, the outflow of hydraulic oil from the piston side chamber 25 is blocked by the lowering prevention valve 33. Thus, by preventing the hydraulic oil from flowing out from the piston-side chamber 25, the boom is prevented from naturally descending by its own weight, and the boom can be stopped reliably.

  According to the above embodiment, there exist the effects shown below.

  In the hybrid work machine control system 100, the boom second speed switching valve 6 performs speed increasing control for increasing the operating speed of the boom cylinder BC by guiding the hydraulic oil to the piston side chamber 25 when the boom cylinder BC is extended. While having the acceleration position 6d performed, it has the regeneration regeneration position 6e in which the regeneration control which makes the piston side chamber 25 and the regeneration motor M communicate, and the regeneration control which makes the piston side chamber 25 and the rod side chamber 30 communicate. That is, the function as a regeneration control valve and the function as a regeneration control valve are integrated into the boom second speed switching valve 6 that functions as an acceleration control valve.

  As described above, since a plurality of functions are integrated in one switching valve, piping for connecting each switching valve and each element is not necessary as compared with the case where switching valves having the respective functions are separately installed. In addition, it is not necessary to secure a space in which each switching valve is arranged. As a result, the cost for manufacturing the control system 100 for the hybrid work machine can be reduced, and the control system 100 for the hybrid work machine can be made compact.

  Hereinafter, a modified example of the control system 100 for the hybrid work machine according to the embodiment will be described.

  In the above-described embodiment, in the boom second speed switching valve 6, the communication flow path 6i for communicating the load side passage 24 and the connection passage 26 is fully open when in the neutral position 6c, and from the neutral position 6c to the regenerative regeneration position 6e. When switched to, it is blocked. Instead of this, as shown by the solid line in FIG. 2, the boom second speed switching valve 6 is displaced from the neutral position 6c to the regenerative regeneration position 6e. It may be gradually decreased with the increase. In this case, the flow of the hydraulic oil is prevented from switching suddenly, and the boom cylinder BC can be operated smoothly.

  Further, as shown by a broken line in FIG. 2, when the neutral position 6c is switched to the regenerative regeneration position 6e, the opening cross-sectional area of the communication flow path 6i that is opened is smaller than that at the neutral position 6c. It is good also as a structure open | released by the predetermined opening degree α which is. The magnitude of the predetermined opening α is set in consideration of the flow rate of hydraulic oil used for regenerative control and regeneration control. In addition, the hydraulic fluid utilized for regeneration control and regeneration control increases, so that predetermined opening degree α is made small.

  In the above-described embodiment, in the boom second speed switching valve 6, the regenerative flow path 6 g that allows the load side passage 24 and the regenerative path 27 to communicate with each other, and the regeneration flow path 6 h that allows the load side passage 24 and the branch path 29 a to communicate with each other. Are closed when in the neutral position 6c, and are fully opened when the neutral position 6c is switched to the regenerative regeneration position 6e. Instead, the opening cross-sectional area (opening) of the regenerative flow path 6g to be opened and the opening cross-sectional area (opening) of the regeneration flow path 6h are linear as shown by a solid line in FIG. As indicated by a broken line, the boom second speed switching valve 6 may be gradually increased as the boom second speed switching valve 6 is displaced from the neutral position 6c to the regenerative regeneration position 6e. In this case, it is possible to prevent the flow of the hydraulic oil from rapidly switching.

  In the above-described embodiment, in the boom second speed switching valve 6, the regenerative flow path 6 g that allows the load side passage 24 and the regenerative path 27 to communicate with each other, and the regeneration flow path 6 h that allows the load side passage 24 and the branch path 29 a to communicate with each other. Are opened at a predetermined opening when switched to the regenerative regeneration position 6e. Instead, the open cross-sectional area (opening) of the regenerative flow path 6g to be opened is indicated by the solid line in FIG. 4, and the open cross-sectional area (opening) of the regenerative flow path 6h to be opened is shown in FIG. As indicated by a broken line, the boom second speed switching valve 6 that is displaced from the neutral position 6c to the regenerative regeneration position 6e may be changed according to the amount of displacement. In this way, the opening cross-sectional area of the regenerative flow path 6g opened according to the displacement amount of the boom second speed switching valve 6 and the opening cross-sectional area of the regeneration flow path 6h are made different so that the regenerative motor M is guided. The distribution between the flow rate of the hydraulic oil and the flow rate of the hydraulic oil guided to the rod side chamber 30 can be changed. The position of the boom second speed switching valve 6 between the neutral position 6c and the regenerative regeneration position 6e changes the command signal to the electromagnetic proportional pressure reducing valve 52 and changes the pilot pressure supplied to the pilot chamber 6b. Can be adjusted.

  In the example shown in FIG. 4, in order to increase the ratio of the flow rate of the hydraulic fluid guided to the regenerative motor M, the position of the boom second speed switching valve 6 is near the middle between the neutral position 6 c and the regenerative regeneration position 6 e. In order to increase the ratio of the flow rate of the hydraulic oil guided to the rod side chamber 30, the position of the boom second speed switching valve 6 may be controlled to be the regenerative regeneration position 6e. When switched to the regeneration regeneration position 6e, the regeneration channel 6g is opened at a predetermined opening degree β, but the opening degree β may be zero. In this way, from the neutral position 6c to the regeneration regeneration position 6e, at least one of the opening cross-sectional area where the regeneration flow path 6g is opened and the opening cross-sectional area where the regeneration flow path 6h is opened is gradually changed. The distribution between the flow rate of the hydraulic fluid guided to the motor M and the flow rate of the hydraulic fluid guided to the rod side chamber 30 can be controlled.

  In the above embodiment, the pilot pressure supplied to the pilot chamber 6 b of the boom second speed switching valve 6 is controlled by the electromagnetic proportional pressure reducing valve 52. Alternatively, the pilot pressure may be changed by controlling the communication opening degree of the pilot passage 51 that communicates the pilot chamber 6b and the pilot hydraulic power source PP with a proportional solenoid valve.

  In the above embodiment, the communication passage 28 that connects the connection passage 26 and the load-side passage 24 is provided, and the check passage 32 is provided in the communication passage 28. Instead of this, the communication passage 28 and the check valve 32 may be eliminated. Even in this case, the connection passage 26 and the load side passage 24 can communicate with each other through the boom second speed switching valve 6. Further, by eliminating the check valve 32 and the like, the configuration can be simplified and the manufacturing cost can be reduced.

  In the above-described embodiment, when the boom operating lever is operated in the direction of raising the boom cylinder BC by the operator, the pilot chamber 17a of the boom switching valve 17 and the pilot chamber 6a of the boom second speed switching valve 6 are moved to the pilot chamber 6a. Pilot pressure is supplied. Instead of this, the pilot pressure may be supplied to the pilot chamber 6a of the boom second speed switching valve 6 when the boom operating lever is operated by a predetermined amount or more in the direction of raising the boom cylinder BC. In this case, it is possible to suppress the boom from rising rapidly. In addition, the timing at which the pilot pressure is supplied to the pilot chamber 6a is delayed by a predetermined period from the timing at which the pilot pressure is supplied to the pilot chamber 17a, and the timing at which the boom second speed switching valve 6 is switched to the acceleration position 6d. It can suppress that a boom raises rapidly also by delaying.

  Hereinafter, the configuration, operation, and effect of the embodiment of the present invention will be described together.

  The control system 100 of the hybrid working machine extends by increasing the load by supplying the hydraulic oil to the piston side chamber 25 and discharging the hydraulic oil from the rod side chamber 30, and supplies the hydraulic oil to the rod side chamber 30 and the piston side chamber 25. Is discharged from the piston side chamber 25, the boom cylinder BC that contracts due to the discharge of the hydraulic oil from the cylinder and lowers the load, the fluid supply sources MP 1, MP 2, AP that supply the hydraulic oil stored in the tank T to the boom cylinder BC A regenerative motor M that is rotated by hydraulic oil, a rotary electric machine 35 that is connected to the regenerative motor M, a regenerative unit RU that has a battery 37 that stores the electric power generated by the rotary electric machine 35, and the hydraulic oil is guided to the piston side chamber 25. The extension position 17d for extending the boom cylinder BC and the hydraulic oil in the piston side chamber 25 are guided to the tank T The boom switching valve 17 having the contracted position 17e for contracting the cylinder cylinder BC, and the hydraulic fluid supplied from the fluid supply sources MP1 and AP when the boom switching valve 17 is at the extended position 17d are guided to the piston side chamber 25. The speed increasing position 6d where the speed increasing flow path 6f is opened, and the regenerative flow path 6g, the piston side chamber 25, and the rod side chamber communicating with the piston side chamber 25 and the regenerative motor M when the boom switching valve 17 is in the contracted position 17e. Switching for the second speed of the boom having a regeneration regeneration position 6e where the regeneration flow path 6h communicating with 30 is opened, and a neutral position 6c where the speed increasing flow path, the regeneration flow path 6g and the regeneration flow path 6h are closed. And a valve 6.

  In this configuration, the speed increasing position where the boom second speed switching valve 6 performs speed increasing control for increasing the operating speed of the boom cylinder BC by guiding the hydraulic oil to the piston side chamber 25 when the boom cylinder BC is extended. 6d and a regeneration regeneration position 6e in which regeneration control for communicating the piston side chamber 25 and the regeneration motor M and regeneration control for communicating the piston side chamber 25 and the rod side chamber 30 are performed. That is, the function as a regeneration control valve and the function as a regeneration control valve are integrated into the boom second speed switching valve 6 that functions as an acceleration control valve.

  As described above, since a plurality of functions are integrated in one switching valve, piping for connecting each switching valve and each element is not necessary as compared with the case where switching valves having the respective functions are separately installed. In addition, it is not necessary to secure a space in which each switching valve is arranged. As a result, the cost for manufacturing the control system 100 for the hybrid work machine can be reduced, and the control system 100 for the hybrid work machine can be made compact. Further, unlike the prior art, the regenerative control valve and the regeneration control valve are not arranged separately, but are arranged in one place, so that the maintainability can be improved.

  Further, the control system 100 for the hybrid work machine connects the connection passage 26 connecting the boom switching valve 17 and the boom second speed switching valve 6, the boom second speed switching valve 6 and the piston side chamber 25, and A load side passage 24 that can communicate with the connection passage 26 through the second-speed switching valve 6, a communication passage 28 that connects the connection passage 26 and the load side passage 24, and the communication passage 28 are provided. And a check valve 32 that allows only the flow of hydraulic oil toward the passage 24. When the boom second speed switching valve 6 is at the acceleration position 6d or the neutral position 6c, the boom switching valve 17 extends. When switched to the position 17d, the hydraulic fluid supplied from the fluid pressure source MP2 to the piston side chamber 25 through the boom switching valve 17 passes through the connection passage 26 and the boom second speed switching valve 6 to load side passage 24. With guided, characterized in that it is guided on the load side passage 24 through the connecting passage 26 and the check valve 32.

  In this configuration, since the connection passage 26 communicates with the load-side passage 24 through the boom second speed switching valve 6, the hydraulic oil discharged from the second main pump MP2 is supplied to the boom switching valve 17, the connection passage 26, It is guided to the piston side chamber 25 of the boom cylinder BC through the boom second speed switching valve 6 and the load side passage 24. The hydraulic oil discharged from the second main pump MP2 is also supplied from the connection passage 26 to the load side passage 24 through the communication passage 28 without passing through the boom second speed switching valve 6.

  In this way, the hydraulic oil discharged from the second main pump MP2 is guided to the piston side chamber 25 through two paths. For this reason, the flow volume of the hydraulic fluid supplied to the piston side chamber 25 is ensured, and the responsiveness of the boom cylinder BC can be improved. Further, since the hydraulic oil can be guided to the piston side chamber 25 without going through the boom second speed switching valve 6 which is a spool valve having a relatively large flow path resistance, the hydraulic oil is supplied to the piston side chamber 25. It is possible to reduce the pressure loss when being performed.

  Further, the control system 100 for the hybrid work machine connects the connection passage 26 connecting the boom switching valve 17 and the boom second speed switching valve 6, the boom second speed switching valve 6 and the piston side chamber 25, and A load-side passage 24 that can communicate with the connection passage 26 through the second-speed switching valve 6, and the boom second-speed switching valve 6 is connected to the load-side passage 24 and the connection passage that are opened when in the neutral position 6 c. The communication channel 6i is further connected, and the area where the communication channel 6i is opened gradually decreases from the neutral position 6c to the regeneration position 6e.

  If the working oil introduced from the load side passage 24 to the connection passage 26 is supplied to the rod side chamber 30 at the moment of switching to the regenerative regeneration position 6e, the operating speed of the boom cylinder BC may change suddenly. In contrast, in this configuration, the opening cross-sectional area of the communication flow path 6i that allows the load side passage 24 and the connection passage 26 to communicate with each other is such that the boom second speed switching valve 6 is displaced from the neutral position 6c to the regenerative regeneration position 6e. Decreases with increasing. For this reason, it is prevented that the flow of the hydraulic fluid led from the load side passage 24 to the connection passage 26 changes rapidly, and the boom cylinder BC can be operated smoothly.

  Further, when the boom second speed switching valve 6 is in the regeneration regeneration position 6e, the communication flow path 6i is closed.

  In this configuration, the communication flow path 6i that connects the load side passage 24 and the connection passage 26 is closed when the boom second speed switching valve 6 is displaced to the regenerative regeneration position 6e. For this reason, all the hydraulic oil discharged from the piston side chamber 25 is guided to either the rod side chamber 30 or the regenerative motor M. Therefore, the energy of all the discharged hydraulic oil can be effectively used.

  In addition, at least one of the area where the regenerative flow path 6g is opened and the area where the regeneration flow path 6h is opened gradually changes from the neutral position 6c to the regenerative regeneration position 6e.

  In this configuration, at least one of the area where the regenerative flow path 6g is opened and the area where the regeneration flow path 6h is opened is the displacement of the boom second speed switching valve 6 which is displaced from the neutral position 6c to the regenerative regeneration position 6e. It will change gradually. As described above, the at least one of the area where the regenerative flow path 6g is opened and the area where the regeneration flow path 6h is opened is changed according to the amount of displacement of the boom second speed switching valve 6 to guide the regenerative motor M. The distribution between the flow rate of the hydraulic oil to be flowed and the flow rate of the hydraulic oil guided to the rod side chamber 30 can be changed by controlling the position of the boom second speed switching valve 6.

  The embodiment of the present invention has been described above. However, the above embodiment only shows a part of application examples of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. Absent.

  In the above embodiment, as an example of performing regeneration using the return hydraulic oil from the fluid pressure cylinder, the case of using the return hydraulic oil from the boom cylinder BC has been described. However, instead of the boom cylinder BC, regeneration may be performed by using return hydraulic oil from an arm cylinder for driving an arm or a bucket cylinder for driving a bucket.

  The working machine is not limited to a hydraulic excavator, and may be a hydraulic crane having a boom driven by a fluid pressure cylinder, an aerial working machine, or the like.

  DESCRIPTION OF SYMBOLS 100 ... Control system of a hybrid working machine, 6 ... Boom 2nd speed switching valve (2nd switching valve), 6a, 6b ... Pilot chamber, 6c ... Neutral position, 6d ... Speed increase Position, 6e ... regenerative regeneration position, 6f ... speed increasing channel, 6g ... regeneration channel, 6h ... regeneration channel, 6i ... communication channel, 9 ... neutral channel, 10 ... Parallel passage, 17 ... Boom switching valve (first switching valve), 17a, 17b ... Pilot chamber, 17c ... Stop position, 17d ... Extension position, 17e ... Contraction Position: 19 ... neutral passage, 20 ... parallel passage, 24 ... load side passage, 25 ... piston side chamber (load side pressure chamber), 26 ... connection passage, 26a ... branch passage 27 ... Regenerative passage, 28 ... Communication passage, 29 ... Non-load side passage, 29a ... Branch passage, 30 ... Rod side chamber (anti-load side pressure chamber), 32 ... Check valve, 33 ... Lowering prevention valve, 35 ... Rotating electric machine, 36 ... Inverter, 37 ... Battery: 52 ... Proportional pressure reducing valve, MP1 ... First main pump (fluid supply source), MP2 ... Second main pump (fluid supply source), AP ... Assist pump (fluid supply source) , T ... tank, BC ... boom cylinder (fluid pressure cylinder), RU ... regenerative unit

Claims (5)

A control system for a hybrid work machine,
The working fluid is supplied to the load side pressure chamber and the working fluid is discharged from the anti-load side pressure chamber to elevate the load, and the working fluid is supplied to the anti-load side pressure chamber and from the load side pressure chamber. A hydraulic cylinder that contracts by discharging the working fluid and lowers the load;
A fluid supply source for supplying a working fluid stored in a tank to the fluid pressure cylinder;
A regenerative motor rotating by a working fluid discharged from the load side pressure chamber, a rotating electric machine connected to the regenerative motor, and a regenerative unit having a storage battery for storing electric power generated by the rotating electric machine;
A first switch having an extended position for guiding the working fluid to the load side pressure chamber and extending the fluid pressure cylinder, and a contracted position for guiding the working fluid in the load side pressure chamber to the tank and contracting the fluid pressure cylinder. A valve,
An acceleration position at which an acceleration flow path for guiding the working fluid supplied from the fluid supply source to the load-side pressure chamber is opened when the first switching valve is in the extended position; and the first switching valve Regenerative regeneration in which the regenerative flow path communicating the load side pressure chamber and the regenerative motor and the regenerative flow path communicating the load side pressure chamber and the anti-load side pressure chamber are opened when in the contracted position. A control system for a hybrid work machine, comprising: a second switching valve having a position and a neutral position at which the speed increasing flow path, the regeneration flow path, and the regeneration flow path are closed. A connection passage connecting the first switching valve and the second switching valve;
A load-side passage that connects the second switching valve and the load-side pressure chamber and is capable of communicating with the connection passage through the second switching valve;
A communication path communicating the connection path and the load side path;
A check valve provided in the communication path and allowing only a flow of working fluid from the connection path toward the load side path, and
When the first switching valve is switched to the extended position when the second switching valve is in the speed increasing position or the neutral position, the fluid pressure source to the load side pressure chamber is passed through the first switching valve. The supplied working fluid is led to the load side passage through the connection passage and the second switching valve, and is led to the load side passage through the connection passage and the check valve. A control system for a hybrid work machine described in 1. A connection passage connecting the first switching valve and the second switching valve;
A load-side passage that connects the second switching valve and the load-side pressure chamber and is capable of communicating with the connection passage through the second switching valve;
The second switching valve further includes a communication channel that communicates the load side channel and the connection channel that are opened when the neutral valve is in the neutral position,
2. The control system for a hybrid working machine according to claim 1, wherein an area in which the communication channel is opened gradually decreases from the neutral position to the regenerative regeneration position.   The control system for a hybrid work machine according to claim 3, wherein the communication channel is closed when the second switching valve is in the regeneration regeneration position.   5. The system according to claim 1, wherein at least one of an area where the regeneration flow path is opened and an area where the regeneration flow path is opened gradually changes from the neutral position to the regeneration regeneration position. The control system of the hybrid work machine as described in any one.