JP5090720B2 - Energy regeneration system for work machines - Google Patents

Description

  The present invention relates to a technical field of an energy regeneration system for a work machine including a fluid pressure actuator, in which energy of discharged fluid is regenerated.

  In general, work machines such as hydraulic excavators are provided with various hydraulic actuators that are actuated by pressurized fluid from a pump, and in relation to the work machines, the energy of the fluid discharged from the hydraulic actuators. For example, a method for recovering the pressure of fluid discharged from each fluid pressure actuator so as to accumulate in an accumulator is known. However, these accumulators cause a problem that a large capacity is required with respect to an energy storage amount as compared with other energy storage means such as a battery, and further a problem that storage time is shortened.

  Therefore, it is necessary to improve a method for regenerating and storing the energy of the fluid discharged from the fluid pressure actuator as electric energy.

  Generally, a work machine such as a hydraulic excavator is configured such that the flow rate of fluid discharged from a fluid pressure actuator is controlled by a control valve that performs meter-out control based on the size of a throttle. In one known embodiment, the method disclosed in Patent Document 1 includes a turbine that is rotationally driven by the inflow of discharged fluid downstream of such a control valve. Thus, before the turbine rotates and regenerates energy, the control valve removes the discharged fluid from the fluid pressure actuator, which results in an increase in temperature, thereby consuming energy and reducing energy regeneration efficiency. The problem arises.

  Furthermore, in Patent Document 1, no consideration is given to the fact that the fluid pressure actuator is a fluid pressure motor, but various fluid pressures such as a hydraulic rotary motor for rotating the upper rotating body and / or the hydraulic drive motor are used. The motor can be included in a work machine such as a hydraulic excavator. Such a fluid pressure motor generally includes a control valve for controlling the flow rate and a relief valve for preventing a pressure increase in the fluid supply passage and / or the discharge passage when the motor is started or stopped. . When the temperature of the fluid passing through the relief valve rises, energy may be consumed. In this case, it is required that the energy of the fluid passing through the relief valve can also be regenerated.

JP 2002-195218 A

  The present disclosure aims to solve this and other problems known to those skilled in the art.

  By this method, a turbine that is rotationally driven by the inflow of the discharge fluid from the fluid pressure cylinder is provided in the discharge flow path. In this case, the generator is allowed to generate electric energy by the driving force of the turbine. In this way, the energy of the discharged fluid can be efficiently regenerated and stored as electric energy, and furthermore, the electric energy can be used as an alternative power source for the engine, which is an environmentally friendly method.

  In one form, the present disclosure provides an energy regeneration system for a work machine. The system includes a fluid pressure actuator adapted to be actuated by supplying / dispensing fluid. Further, the system is a variable capacity regenerative fluid pressure motor in a discharge flow path for fluid discharged from the fluid pressure actuator, and controls the displacement volume of the regenerative fluid pressure motor to thereby remove the fluid pressure actuator from the fluid pressure actuator. It includes a variable capacity regenerative fluid pressure motor that is allowed to control the flow rate of the discharge fluid and the pressure of the discharge flow path. In addition, the system includes an energy regeneration device for regenerating the energy of the discharged fluid as electrical energy by at least partially rotating the regenerative fluid pressure motor.

  In another aspect, the present disclosure provides a hydraulic actuator having first and second supply / discharge ports and first and second flow controls connected to the first and second supply / discharge ports, respectively. A work machine including a flow control circuit including a line is provided. Further, the work machine has at least one variable displacement hydraulic motor in the flow control circuit, and at least one disposed in the flow control circuit between the at least one variable displacement hydraulic motor and the hydraulic actuator. Includes two pressure sensitive means. In addition, the work machine includes an energy regeneration device connected to a variable displacement hydraulic motor for regenerating at least part of the energy of the discharge fluid of the hydraulic actuator as electric energy.

  In yet another aspect, the present disclosure provides a method of operating a hydraulic energy recovery system.

  In FIG. 1, a hydraulic motor 1 (for example, a hydraulic rotary motor for rotating an upper rotating body of a hydraulic excavator) is provided in a work machine such as a hydraulic excavator, and includes first and second oil supply and oil discharge. The hydraulic motor 1 having the ports 1a and 1b is a bi-directional rotating type, and supplies pressure oil to the first oil supply and oil discharge port 1a and discharges oil from the second oil supply and oil discharge port 1b. , And when the pressure oil is supplied to the second oil supply and oil discharge port 1b and the oil is discharged from the first oil supply and oil discharge port 1a, the oil rotates in the opposite direction. Are arranged as follows.

  The hydraulic motor 1 includes a hydraulic pump 2 as a pressure oil supply source to the hydraulic motor 1. The hydraulic pump 2 is adapted to be driven using an engine 32 attached to a work machine as a main power source and a motor 33 described below as an auxiliary power source. In this case, the hydraulic pump 2 and the hydraulic pump A hydraulic circuit is provided between the motor 1 and the hydraulic circuit. The hydraulic circuit includes a discharge line 3 connected to the discharge side of the hydraulic pump 2, a flow control circuit 4 connected to the downstream side of the discharge line 3, and a flow control. A first motor-side line 5 adapted to connect the circuit 4 to the first oil supply and oil discharge port 1a of the hydraulic motor 1, and the second oil supply and the flow control circuit 4 to the hydraulic motor 1; A second motor side line 6 adapted to connect to the oil discharge port 1b is included.

  A return line 8 to the oil tank 7 is formed in the middle portion of the discharge line 3 so as to branch. On the return line 8 is a bypass valve 9 arranged to operate based at least in part on commands from the controller 10 described below. Further, in the discharge line 3, a check valve 11 is disposed on the downstream side of the branch point for the return line 8, and the check valve 11 prevents backflow of oil to the hydraulic pump 2 and the return line 8.

  The flow rate control circuit 4 is formed by connecting the first, second, third and fourth flow rate control lines 12, 13, 14, 15 in a rectangular annular shape as will be described below. The discharge line 3 is connected to a connection portion A between the first flow rate control line 12 and the second flow rate control line 13. The first motor side line 5 is connected to a connection portion B between the first flow rate control line 12 and the third flow rate control line 14. The second motor side line is connected to a connection portion C between the second flow rate control line 13 and the fourth flow rate control line 15. Finally, the discharge line 16 reaching the oil tank 7 is connected to a connection portion D between the third flow rate control line 14 and the fourth flow rate control line 15.

  The first flow rate control line 12 is provided with a first meter-in valve 17 adapted to control the flow rate of the supply oil from the discharge line 3 to the first motor side line 5. The second flow rate control line 13 is provided with a second meter-in valve 18 adapted to control the flow rate of supply oil from the discharge line 3 to the second motor side line 6. The first and second meter-in valves 17 and 18 are controlled by the control device 10 so as to be operable.

  In addition, a first variable displacement regenerative hydraulic motor 19 is disposed in the third flow rate control line 14. The displacement of the first regenerative hydraulic motor 19 changes from zero to a predetermined maximum value based on a control command output from the control device 10 to the displacement control means 19a. It is allowed to change the flow rate in line 14 from zero to a predetermined maximum value. Next, the flow rate control (meter-out control) of the discharge oil from the first motor side line 5 to the discharge line 16 and the pressure of the first motor side line 5 are performed by the change in displacement of the first regenerative hydraulic motor 19. Control is allowed. Further, a first pressure sensor 20 for detecting the pressure of the third flow rate control line 14 on the upstream side of the first regenerative hydraulic motor 19 is disposed in the third flow rate control line 14. The pressure sensor 20 is arranged to output a detection signal to the control device 10.

  The fourth flow rate control line 15 includes a second regenerative hydraulic motor 21 and a second pressure similar to the first regenerative hydraulic motor 19 and the first pressure sensor 20 arranged in the third flow rate control line 14. A sensor 22 is arranged. Next, the displacement of the second regenerative hydraulic motor 21 is changed based on the control command output from the control device 10 to the displacement control means 21a of the second regenerative hydraulic motor 21, whereby the second motor Flow control (meter-out control) of discharged oil from the side line 6 to the discharge line 16 and pressure control of the second motor side line 6 are allowed.

  The first and second generators 23 and 24 are connected so as to interlock with the first and second regenerative hydraulic motors 19 and 21, respectively. The first and second generators 23 and 24 can be driven by the torques of the first and second regenerative hydraulic motors 19 and 21 to generate electric power.

  The third and fourth flow control lines 14 and 15 also include bypass lines 14a and 15a for bypassing the first and second regenerative hydraulic motors 19 and 21, respectively. The bypass lines 14a and 15a are arranged so as to allow oil flow from the discharge line 16 to the first motor side line 5 and the second motor side line 6, but to prevent oil flow in the opposite direction. Check valves 25 and 26 are arranged respectively. In this manner, oil is supplied from the oil tank 7 when the first motor side line 5 or the second motor side line 6 is in a reduced pressure state.

  The control device 10 composed of a microcomputer or the like receives the command signal output from the control lever 27 for the hydraulic motor 1 and the detection signals output from the first and second pressure sensors 20 and 22, and then Based on the input signal, the displacement control means 2a of the hydraulic pump 2, the bypass valve 9, the first and second meter-in valves 17 and 18, and the first and second regenerative hydraulic motors 19 and 21 are displaced. A control command is output to the volume control means 19a and 21a.

  When the control lever 27 for the hydraulic motor 1 is positioned at the stop position with respect to the control command output from the control device 10 (that is, no operation is performed with the control lever 27), the control device 10 ”Is output to the bypass valve 9, while“ valve closure ”is output to the first and second meter-in valves 17 and 18, and a control command of“ zero displacement ”is output to the first and second valves. Output to the displacement control means 19a and 21a of the second regenerative hydraulic motors 19 and 21. Thus, the oil forcibly sent from the hydraulic pump 2 is returned to the oil tank 7 through the return line 8, where the first to fourth flow control lines 12 to 15 are in a closed state. Oil is not supplied to or discharged from the hydraulic motor 1, and therefore the hydraulic motor 1 stops.

  On the other hand, when the control lever 27 is in a position instructed to rotate the hydraulic motor 1 in one direction, the control device 10 outputs a control command “valve closing” to the bypass valve 9, A control command “open” is output to the first meter-in valve 17, and a control command “close valve” is output to the second meter-in valve 18. In this case, the opening of the first meter-in valve 17 is controlled to increase or decrease in accordance with the increase or decrease of the operation magnitude of the control lever 27. In addition, when the pressure P1 of the third flow rate control line 14 detected by the first pressure sensor 20 is equal to or lower than the predetermined relief pressure PS, the control device 10 sends a control command “no displacement volume” to the first. Is output to the displacement control means 19a of the regenerative hydraulic motor 19 and, on the other hand, if the pressure P1 is larger than a predetermined relief pressure PS, a control command is given to the displacement control means 19a to give a predetermined relief displacement. Output. Further, the control device 10 increases or decreases the magnitude of the operation of the control lever 27 when the pressure P2 of the fourth flow rate control line 15 detected by the second pressure sensor 22 is equal to or lower than a predetermined relief pressure. A control command is output to the displacement control means 21a of the second regenerative hydraulic motor 21 so that the displacement is increased or decreased according to the above. When the pressure P2 is larger than the predetermined relief pressure PS, the relief displacement is obtained. Such a control command is output to the displacement control means 21a. In this case, when the displacement volume of the second regenerative hydraulic motor 21 corresponding to the magnitude of the operation of the control lever 27 is larger than the relief displacement volume, the motor does not depend on the pressure of the fourth flow control line 15. The displacement of the control lever 27 is controlled to correspond to the magnitude of the operation.

  Therefore, the oil forcibly sent from the hydraulic pump 2 flows through the discharge line 3 to the first flow rate control line 12, and then passes through the first motor side line 5 to the first oil of the hydraulic motor 1. The oil flow rate is controlled by a first meter-in valve 17 disposed in the first flow rate control line 12 so as to be supplied to the supply and oil discharge port 1a. On the other hand, the oil discharged from the second oil supply and oil discharge port 1b flows through the second motor side line 6 to the fourth flow rate control line 15, and then flows into the oil tank 7 through the discharge line 16. As described above, the flow rate is controlled by the second regenerative hydraulic motor 21 arranged in the fourth flow rate control line 15, whereby the hydraulic motor 1 rotates in one direction. Further, when the hydraulic motor 1 rotates in one direction, the second regenerative hydraulic motor 21 that controls the flow rate in the discharge flow path from the hydraulic motor 1 rotates at least partially, so that the second generator 24 is driven. To generate power.

  On the other hand, when the control lever 27 is returned to the stop position and the hydraulic motor 1 operating in the one-way rotation state is stopped, the displacement volume of the second regenerative hydraulic motor 21 is reduced from the control lever 27. The fourth flow rate control line 15 is controlled to be zero based on the operation command, and the hydraulic motor 1 is immediately stopped because the inertial load is applied and the motor is still rotating. The oil discharged from the hydraulic motor 1 rotating in this way flows through the second motor side line 6 to the fourth flow rate control line 15, and the fourth flow rate control line 15. Increase the pressure. The pressure P2 of the fourth flow rate control line 15 is detected by the second pressure sensor 22, and when the pressure P2 of the fourth flow rate control line 15 becomes equal to or higher than a predetermined relief pressure PS, the control device 10 As described above, the control command is output to the second regenerative hydraulic motor 21 such that the relief displacement volume is obtained. In this way, the fourth flow rate control line 15 is in a state where oil passes through, and here, the second regenerative hydraulic motor 21 has a rotational resistance enough to maintain a predetermined relief pressure PS. Next, the discharged oil is allowed to flow from the hydraulic motor 1 to the oil tank 7. Therefore, the second regenerative hydraulic motor 21 performs the relief control when the motor is stopped, and when operated for the relief control, the second regenerative hydraulic motor 21 rotates to cause the second generator 24 is driven to generate power.

  Further, when the hydraulic motor 1 rotates in one direction, the first flow rate control line 12 and the first motor side line 5 function as a pressure oil supply flow path to the hydraulic motor 1. The third flow rate control line 14 that reaches the oil tank 7 is connected to a connection portion B that is disposed at an intermediate portion of the pressure oil supply flow path. For example, when the hydraulic motor 1 rotates in one direction, the third flow rate control line 14 corresponds to a relief flow path connected to the pressure oil supply flow path.

  On the other hand, when the hydraulic motor 1 changes from the stopped state to the rotating state, the pressure in the pressure oil supply channel to the hydraulic motor 1 increases due to the time lag of the motor that is started by the inertia load applied to the hydraulic motor 1. The increased pressure flows through the connection B to the third flow control line 14 as detected by the first pressure sensor 20. Here, when the pressure P1 of the third flow rate control line 14 becomes larger than the predetermined relief pressure PS, the displacement volume of the first regenerative hydraulic motor 19 is determined by the command from the control device 10 as described above. Based on this, control is performed so that the relief displacement volume is obtained, so that the pressure oil in the pressure oil supply passage is released to the oil tank 7 through the third flow rate control line 14 and the discharge line 16. In this way, the first regenerative hydraulic motor 19 can perform the relief control when the motor is started, and the rotation of the first regenerative hydraulic motor 19 that is operated for the relief control in this way. Thus, it is possible to drive the first generator 23 to generate electric power.

  On the other hand, when the control lever 27 is operated to a position instructed to rotate the hydraulic motor 1 in the opposite direction, the control device 10 outputs a control command “valve closing” to the bypass valve 9, The control command “closed” is output to the first meter-in valve 17, while the control command “open valve” is output to the second meter-in valve 18. In this case, the size of the opening of the second meter-in valve 18 is controlled to increase or decrease in accordance with the increase or decrease of the operation magnitude of the control lever 27. Further, the control device 10 increases the magnitude of the operation of the control lever 27 when the pressure P1 of the third flow rate control line 14 detected by the first pressure sensor 20 is equal to or lower than a predetermined relief pressure PS. Alternatively, a control command is output to the displacement control means 19a of the first regenerative hydraulic motor 19 so that the displacement is increased or decreased according to the decrease. On the other hand, if the pressure P1 is greater than the predetermined relief pressure PS, A control command for the displacement volume is output to the displacement volume control means 19a. Here, when the displacement volume of the first regenerative hydraulic motor 19 corresponding to the magnitude of the operation of the control lever 27 is larger than the relief displacement volume, the motor is independent of the pressure of the third flow rate control line 14. The displacement of the control lever 27 is controlled to correspond to the magnitude of the operation. Further, when the pressure P2 of the fourth flow rate control line 15 detected by the second pressure sensor 22 is equal to or lower than the predetermined relief pressure PS, the control device 10 sends a control command “no displacement volume” to the first control command. 2 is output to the displacement control means 21a of the regenerative hydraulic motor 21. On the other hand, if the pressure P2 is larger than the predetermined relief pressure PS, a control command is output to the displacement control means 21a so as to obtain a relief displacement. To do. Therefore, the oil forcibly sent from the hydraulic pump 2 flows to the second flow rate control line 13 through the discharge line 3, and then the second oil supply of the hydraulic motor 1 through the second motor side line 6. The oil flow rate is controlled by the second meter-in valve 18 disposed in the second flow rate control line 13 so as to be supplied to the oil discharge port 1b. On the other hand, the first oil supply on one side and the discharge oil from the oil discharge port 1a flow to the third flow rate control line 14 through the first motor side line 5, and then to the oil tank through the discharge line 16. The flow rate of the oil is controlled by the first regenerative hydraulic motor 19 arranged in the third flow rate control line 14 so as to flow into the oil flow rate 7, whereby the hydraulic motor 1 rotates in the opposite direction. Further, when the hydraulic motor 1 rotates in the opposite direction, the first regenerative hydraulic motor 19 that controls the flow rate in the discharge flow path from the hydraulic motor 1 rotates, so that the first generator 23 is driven to generate electric power. Let

  When the rotation of the hydraulic motor 1 in the opposite direction is stopped, the first regenerative hydraulic motor 19 arranged in the discharge flow path performs the relief control, as in the case of the rotation in the one direction as described above. The first generator 23 is driven by the rotation of the first regenerative hydraulic motor 19 that is operated for relief control to generate electric power. Further, when the hydraulic motor 1 starts to rotate in the opposite direction, the fourth flow rate control line 15 functions as a relief channel connected to the pressure oil supply channel, and is disposed here in the relief channel. The second regenerative hydraulic motor 21 performs the relief control, and the second generator 24 is driven by the rotation of the second regenerative hydraulic motor 21 that is operated for the relief control in this way to generate electric power. Let

  As described above, when the hydraulic motor 1 is rotated, started, and stopped, the first and second generators 23 and 24 are driven by the rotation of the first and second regenerative hydraulic motors 19 and 21 to generate electric power. And the electric power is rectified by the diode 28 so as to be stored in the capacitor 29 and the storage battery 30. Next, the electric power stored in the capacitor 29 and the storage battery 30 is supplied to the auxiliary power source for the hydraulic pump 2 through a converter 31 for converting DC power into AC power and for controlling the voltage. Is supplied to a motor 33 that functions as:

  In the embodiment as described above, when the hydraulic motor 1 rotates, the pressure oil is supplied to one oil supply and oil discharge port 1a (or the other oil supply and oil discharge port 1b), while the oil is the other oil. The oil discharged from the supply and oil discharge port 1b (or one oil supply and oil discharge port 1a) and the oil discharged from the second oil supply and oil discharge port 1b (or one oil supply and oil discharge port 1a) are It flows through the second motor side line 6 (or the first motor side line 5) to the fourth flow rate control line 15 (or the third flow rate control line 14), and then the discharge line 16 as described above. The second variable displacement regenerative hydraulic motor 21 (or the second variable displacement regenerative hydraulic motor 21 disposed in the fourth flow control line 15 (or the third flow control line 14)). It is controlled by a first regenerative hydraulic motor 19) (meter-out control). The second generator 24 (or the first generator 23) is driven by the rotation of the second regenerative hydraulic motor 21 (or the first regenerative hydraulic motor 19) to generate electric power.

  As described above, when the hydraulic motor 1 is started or stopped, the first and second regenerative hydraulic motors 19 and 21 perform pressure control (relief control). In this pressure control, the supply flow path or the discharge flow is controlled. When the pressure in the passage becomes equal to or higher than a predetermined relief pressure, the oil in the passage is guided to the oil tank 7 to prevent the pressure oil supply passage or the oil discharge passage from increasing in pressure. As a result, the first and second regenerative hydraulic motors 19 and 21 are rotated to drive the first and second generators 23 and 24 to generate electric power. The power generated by driving the first and second generators 23 and 24 is stored in the capacitor 29 and the storage battery 30, and the stored power is supplied to the motor 33 that functions as an auxiliary power source for the hydraulic pump. It is possible to supply.

  As described above, in the embodiment of the present invention, the first and second regenerative hydraulic motors 19 and 21 are rotated by the inflow of discharged oil from the hydraulic motor 1 during rotation, or the discharged oil is motor The first and second generators 23 and 24 generate electric power by the rotational driving of the first and second regenerative hydraulic motors 19 and 21. In this way, the energy of the discharged oil can be regenerated as electric energy, where the first and second regenerative hydraulic motors 19 and 21 not only drive the first and second generators 23 and 24. Also, the flow rate control of the discharge oil from the hydraulic motor 1 and the pressure control (relief control) of the pressure oil supply passage and the oil discharge passage are performed.

  Therefore, it is not necessary to provide a flow control valve or a relief valve for discharging oil from the hydraulic motor 1, and as a result, no energy loss occurs when the flow control valve or the relief valve passes. In this way, the energy of the discharged oil can be regenerated with high efficiency as electric energy, and this makes it possible to achieve an improvement in energy regeneration efficiency. If regenerative electrical energy is used as the power source of the motor 33 that functions as an auxiliary power source for driving the hydraulic pump 2, the reduction of fossil fuel consumed by the engine 32 is allowed, which can contribute to energy saving. Also friendly to the environment.

  Furthermore, neither a flow control valve nor a relief valve for discharged oil is required, which can contribute to a reduction in the number of parts. The relief flow path connected to the pressure oil supply path to one oil supply and oil discharge port 1a (or the other oil supply and oil discharge port 1b) of the hydraulic motor 1 is one oil supply and oil discharge port 1a. Since the circuit is configured to function as a discharge flow path from the other oil supply and oil discharge port 1b, the pressure is reduced when the hydraulic motor 1 starts to rotate in one direction (or in the opposite direction). The first regenerative hydraulic motor 19 (or the second regenerative hydraulic motor 21) that controls the pressure of the oil supply passage performs discharge flow rate control when the motor rotates in the opposite direction (or in one direction), and When rotation in the opposite direction (or in one direction) stops, pressure control of the discharge flow path is performed. Therefore, there is no need to provide separate regenerative fluid pressure motors for the relief flow path and the discharge flow path, and as a result, the number of regenerative hydraulic motors and the number of generators connected thereto are reduced, Contributes to cost reduction and space saving.

  Next, the present invention is not limited to the above embodiment, and when the motor 33 is sufficient as a power source for driving the hydraulic pump 2, the hydraulic pump 2 is driven only by the motor 33 without using the engine. It will be appreciated that the present invention can be configured similarly to the second embodiment shown in FIG. Further, the device for storing the electric power generated by the generators 23 and 24 is not limited to the capacitor 29 or the storage battery 30, and can be configured in the same manner as the third embodiment shown in FIG. This embodiment includes an electrolysis cell 34 for electrolyzing water using power generated by the generators 23 and 24 to generate hydrogen and oxygen, and a hydrogen storage for storing the hydrogen generated in the electrolysis cell 34. A fuel comprising a hydrogen storage device 35 including an alloy and a fuel cell 36 for generating electric power using hydrogen and oxygen as fuel and driving the motor 33 using electric power supplied from the fuel cell device 37 This is an embodiment including the battery device 37. In the second and third embodiments, components common to (same as) the components described in the first embodiment are denoted by the same reference numerals in order to omit their description. Please note that.

  Furthermore, although the hydraulic motor has been described as the fluid pressure actuator in the above embodiment, the above embodiment may be applied to a hydraulic cylinder. Furthermore, not only the pressurized fluid in the hydraulic field but also the pneumatic field. It can be widely applied to pressurized fluids.

  Finally, the above embodiment regenerates the energy of the discharged fluid from the fluid pressure actuator as a power source for the motor to drive a pump adapted to supply pressurized fluid to the fluid pressure actuator However, it is understood that the electrical energy can be used for various electrical machines attached to the work machine. Those skilled in the art will appreciate these and other advantages or forms of the above disclosure based on the appended claims, drawings, and detailed description of the invention.

1 is a drawing of an energy regeneration system according to a first embodiment of the present disclosure. 2 is a drawing of an energy regeneration system according to a second embodiment of the present disclosure in which the same elements have the same numbers as in FIG. 4 is a diagram of an energy regeneration system according to a third embodiment of the present disclosure in which the same elements have the same numbers as in FIGS.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hydraulic motor 1a 1st oil supply and oil discharge port 1b 2nd oil supply and oil discharge port 2 Hydraulic pump 2a Displacement volume control means 3 Discharge line 4 Flow control circuit 5 1st motor side line 6 2nd motor Side line 7 Oil tank 8 Return line 9 Bypass line 10 Control device 11 Check valve 12 First flow control line 13 Second flow control line 14 Third flow control line 14a Bypass line 15 Fourth flow control line 15a Bypass Line 16 Discharge line 17 First meter-in valve 18 Second meter-in valve 19 First regenerative motor 19a Displacement volume control means 20 First pressure sensor 21 Second regenerative motor 21a Displacement volume control means 22 Second Pressure sensor 23 First generator 24 Second generator 25 Che Click valve 26 Check valve 27 Control lever 28 diode 29 capacitor 30 power storage battery 31 converter 32 engine 33 motor A connection port B connection port C connecting port D connection port

Claims (7)

An energy regeneration system for a work machine,
A hydraulic actuator adapted to be actuated by supplying / dispensing fluid, wherein the hydraulic actuator is a bi-directional rotary hydraulic motor having two fluid supply and discharge ports ;
A variable capacity regenerative fluid pressure motor in a discharge flow path for fluid discharged from a fluid pressure actuator, wherein the displacement of the regenerative fluid pressure motor is controlled to control the flow rate of discharged fluid from the fluid pressure actuator and It is allowed to control the pressure of the discharge flow path, and the displacement volume of the regenerative fluid pressure motor is controlled so that the flow rate of the discharge fluid from the fluid pressure actuator changes from zero to a predetermined maximum value. A variable capacity regenerative fluid pressure motor;
A first energy regeneration device for regenerating the energy of the discharged fluid as electrical energy by at least partially rotating a regenerative fluid pressure motor;
A variable capacity regenerative fluid pressure motor in a relief passage connected to a supply passage for fluid supplied to a fluid pressure actuator between an intermediate portion of the supply passage and a fluid tank, wherein the regenerative fluid pressure A second variable capacity regenerative fluid pressure motor allowed to control the pressure of the supply flow path to the fluid pressure actuator by controlling the displacement of the motor;
A second energy regeneration device for regenerating the energy of the fluid in the relief flow path as electrical energy by at least partially rotating the regenerative fluid pressure motor;
The first and second regenerative fluid pressure motors are variable displacement fluid pressure motors provided in discharge channels for fluid discharged from the fluid supply and discharge ports, respectively.
Energy regeneration system for work machines. When the pressure control of the discharge flow path and / or the supply flow path performed by the regenerative fluid pressure motor is relief control, and the pressure of the discharge flow path and / or the supply flow path reaches a predetermined relief pressure in the relief control. The energy regeneration system for work machines according to claim 1 , wherein fluid in the discharge flow path and / or the supply flow path is released.   The energy regeneration system for work machines according to claim 1, wherein the flow rate of the supply fluid to the fluid pressure actuator is controlled by a supply flow rate control valve. The relief flow path is connected to a supply flow path for fluid supplied to one of the fluid supply and discharge ports of the bi-directional rotating fluid pressure motor between the intermediate portion of the supply flow path and the fluid tank,
The energy regeneration system for a work machine according to claim 1 , wherein the relief flow path is adapted to function as a discharge flow path for fluid discharged from one of the fluid supply and discharge ports. A control device operable to receive an operation signal from a fluid pressure actuator operation tool and a detection signal from a pressure detection means for detecting a pressure in a discharge channel and / or a supply channel of the fluid pressure actuator. is equipped to the working machine, further wherein the controller, based on the operation signal and the detection signal, wherein the control command to claim 4 which is operable to output a displacement control means for regeneration fluid pressure motor Energy regeneration system for work machines   2. The work machine according to claim 1, wherein the electrical energy obtained by the energy regeneration device is used as a power source for a motor for driving a pump adapted to supply pressurized fluid to a hydraulic motor. Energy regeneration system. The energy regeneration system for work machines according to claim 6 , wherein the motor is used as an auxiliary power source for the pump.

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