WO2017086109A1 - Hydraulic drive device for cargo vehicles - Google Patents

Hydraulic drive device for cargo vehicles Download PDF

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Publication number
WO2017086109A1
WO2017086109A1 PCT/JP2016/081760 JP2016081760W WO2017086109A1 WO 2017086109 A1 WO2017086109 A1 WO 2017086109A1 JP 2016081760 W JP2016081760 W JP 2016081760W WO 2017086109 A1 WO2017086109 A1 WO 2017086109A1
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WO
WIPO (PCT)
Prior art keywords
hydraulic
flow rate
cylinder
hydraulic oil
control valve
Prior art date
Application number
PCT/JP2016/081760
Other languages
French (fr)
Japanese (ja)
Inventor
祐規 上田
尚也 横町
力 松尾
峰志 宇野
Original Assignee
株式会社豊田自動織機
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 株式会社豊田自動織機 filed Critical 株式会社豊田自動織機
Priority to DE112016005297.9T priority Critical patent/DE112016005297B4/en
Publication of WO2017086109A1 publication Critical patent/WO2017086109A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B66—HOISTING; LIFTING; HAULING
    • B66F—HOISTING, LIFTING, HAULING OR PUSHING, NOT OTHERWISE PROVIDED FOR, e.g. DEVICES WHICH APPLY A LIFTING OR PUSHING FORCE DIRECTLY TO THE SURFACE OF A LOAD
    • B66F9/00—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes
    • B66F9/06—Devices for lifting or lowering bulky or heavy goods for loading or unloading purposes movable, with their loads, on wheels or the like, e.g. fork-lift trucks
    • B66F9/075—Constructional features or details
    • B66F9/20—Means for actuating or controlling masts, platforms, or forks
    • B66F9/22—Hydraulic devices or systems

Definitions

  • the present invention relates to a hydraulic drive device for a cargo handling vehicle.
  • the hydraulic drive device described in Patent Document 1 includes a lifting hydraulic cylinder that lifts and lowers a lifting object by supplying and discharging hydraulic oil, a lifting operation unit for operating the lifting hydraulic cylinder, a lifting hydraulic cylinder, and other actuators.
  • a hydraulic pump that supplies and discharges hydraulic oil to and from the hydraulic cylinder, an electric motor that drives the hydraulic pump, a suction port of the hydraulic pump, and a bottom chamber of the lifting hydraulic cylinder; And a control valve that controls the flow of hydraulic oil based on the operation amount of the lowering operation.
  • the motor speed is controlled so that the other actuators can be operated at a desired speed
  • the lowering speed of the lifting object is reduced. There was a possibility that it would be faster or slower than the desired speed. Therefore, when the lowering operation of the lifting hydraulic cylinder and the operation of other hydraulic cylinders are performed simultaneously, it is required to control the rotation speed of the electric motor so that the lifting object can be lowered at a desired lowering speed. It was.
  • An object of the present invention is to provide a hydraulic drive device for a cargo handling vehicle capable of lowering an ascending / descending object at a desired lowering speed when a lowering operation of a lifting hydraulic cylinder and an operation of another hydraulic cylinder are performed simultaneously. That is.
  • a hydraulic drive device for a cargo handling vehicle performs a first hydraulic cylinder for raising and lowering a lifted object by supplying and discharging hydraulic oil and an operation different from that of the first hydraulic cylinder by supplying and discharging hydraulic oil.
  • the second hydraulic cylinder, the first operating part for operating the first hydraulic cylinder, the second operating part for operating the second hydraulic cylinder, and the supply of hydraulic oil to the first hydraulic cylinder and the second hydraulic cylinder A hydraulic pump that discharges, an electric motor that is connected to the hydraulic pump and functions as an electric motor or a generator, a tank that stores hydraulic oil, a suction port of the hydraulic pump, and a first hydraulic cylinder are connected to each other; A first hydraulic fluid passage for sending hydraulic fluid from the hydraulic cylinder to the hydraulic pump, a branch point on the first hydraulic fluid passage, and a tank are connected, and the hydraulic fluid from the first hydraulic cylinder is returned to the tank.
  • Second of A hydraulic flow path a first flow rate control valve disposed on the second hydraulic oil path and controlling the flow rate of the hydraulic oil returning from the first hydraulic cylinder to the tank;
  • a second flow rate control valve that is disposed between the suction port and the branch point and controls the flow rate of the hydraulic fluid flowing from the first hydraulic cylinder to the hydraulic pump, and the lowering operation and the second operation by the first operation unit
  • the second flow rate control valve is moved from the first hydraulic cylinder to the hydraulic pump. Control to reduce the flow rate of the working fluid.
  • the second hydraulic fluid passage is connected to the hydraulic fluid from the first hydraulic cylinder via the branch point from the first hydraulic fluid passage for sending hydraulic fluid to the hydraulic pump.
  • a first flow rate control valve for controlling the flow rate of the hydraulic fluid returning from the first hydraulic cylinder to the tank is disposed on the second hydraulic fluid passage.
  • a second flow rate control valve for controlling the flow rate of the hydraulic oil flowing from the first hydraulic cylinder to the hydraulic pump is disposed between the suction port of the hydraulic pump and the branch point. Yes.
  • the lowering operation by the first operation unit and the operation of the second operation unit are performed at the same time, so that the motor rotation speed is increased compared with the single operation of the first operation unit, and the flow rate of the hydraulic pump is increased.
  • it can control that a fork lowering speed increases rapidly by controlling so that the 2nd flow control valve may control the flow of hydraulic oil which goes to the hydraulic pump from the 1st hydraulic cylinder.
  • the elevator can be lowered at a desired lowering speed.
  • the flow rate of the hydraulic fluid that can be controlled by the second flow rate control valve is set to be higher than the flow rate of the hydraulic fluid that can be controlled by the first flow rate control valve. May have been.
  • the lowering speed of the lifting / lowering object is kept constant by controlling the second flow rate control valve, and the lowering speed of the lifting / lowering object is kept constant by the control of the first flow rate control valve. In comparison with the case, the descending speed of the lifted object by the control of the second flow rate control valve can be made higher.
  • a transition portion in which the descending speed of the ascending / descending object is partially increased with the motor rotational speed at a portion where the control by the first flow control valve is shifted to the control by the second flow control valve. Can be provided. By such a transition part, it can suppress that it changes suddenly from control by the 1st flow control valve to control by the 2nd flow control valve.
  • the first hydraulic fluid passage is disposed between the first hydraulic cylinder and the branch point, and is operated to lower the first operation portion.
  • a proportional valve that opens at an opening according to the amount, and the second flow control valve may control the flow rate of the hydraulic oil based on a pressure difference before and after the proportional valve.
  • the 2nd flow control valve can be controlled by the descent speed of the raising / lowering object according to the operation amount of the descent operation of the 1st operation part.
  • the first hydraulic fluid passage is disposed between the first hydraulic cylinder and the branch point, and is operated to lower the first operation portion.
  • a proportional valve that opens at an opening according to the amount, and the first flow control valve may control the flow rate of the hydraulic oil based on a pressure difference before and after the proportional valve.
  • the lifting object when the lowering operation of the lifting hydraulic cylinder and the operation of other hydraulic cylinders are performed simultaneously, the lifting object can be lowered at a desired lowering speed.
  • FIG. 1 is a side view showing a cargo handling vehicle including a hydraulic drive device according to an embodiment of the present invention.
  • FIG. 2 is a hydraulic circuit diagram showing the hydraulic drive device according to the embodiment of the present invention.
  • FIG. 3 is a block diagram showing a control system of the hydraulic drive apparatus shown in FIG. 4 is a block diagram showing a control system of the hydraulic drive apparatus shown in FIG.
  • FIG. 5 is a flowchart showing a control processing procedure executed by the controller shown in FIG.
  • FIG. 6A is a graph showing the relationship between the descending operation amount and the motor rotation speed
  • FIG. 6B is a graph showing the relationship between the motor rotation speed and the cylinder flow rate.
  • FIGS. 7A, 7B, and 7C are diagrams illustrating timing charts of the motor rotation speed according to each control mode.
  • FIG. 8 is a diagram illustrating a timing chart of the motor rotation speed according to each control mode.
  • FIG. 1 is a side view showing a cargo handling vehicle equipped with a hydraulic drive device according to an embodiment of the present invention.
  • a cargo handling vehicle 1 according to the present embodiment is a battery-type forklift.
  • the cargo handling vehicle 1 includes a body frame 2 and a mast 3 disposed at a front portion of the body frame 2.
  • the mast 3 includes a pair of left and right outer masts 3a supported to be tiltable on the vehicle body frame 2, and an inner mast 3b which is disposed inside these outer masts 3a and can be moved up and down with respect to the outer mast 3a. Yes.
  • a lift cylinder 4 as a lifting hydraulic cylinder is disposed on the rear side of the mast 3.
  • the tip of the piston rod 4p of the lift cylinder 4 is connected to the upper part of the inner mast 3b.
  • the lift bracket 5 is supported on the inner mast 3b so as to be movable up and down.
  • a fork (lifting object) 6 for loading a load is attached to the lift bracket 5.
  • a chain wheel 7 is provided on the upper portion of the inner mast 3b, and a chain 8 is hooked on the chain wheel 7.
  • One end of the chain 8 is connected to the lift cylinder 4, and the other end of the chain 8 is connected to the lift bracket 5.
  • a tilt cylinder 9 as a tilting hydraulic cylinder is supported on each of the left and right sides of the body frame 2.
  • the tip of the piston rod 9p of the tilt cylinder 9 is rotatably connected to the substantially central portion of the outer mast 3a in the height direction.
  • a driver's cab 10 is provided on the upper part of the body frame 2. At the front of the cab 10, there are provided a lift operation lever 11 for operating the lift cylinder 4 to raise and lower the fork 6, and a tilt operation lever 12 for operating the tilt cylinder 9 to tilt the mast 3. It has been.
  • a steering wheel 13 for steering is provided at the front of the cab 10.
  • the steering 13 is a hydraulic power steering, and can assist the driver's steering by a PS cylinder 14 (see FIG. 2) as a hydraulic cylinder for power steering (PS).
  • PS hydraulic cylinder for power steering
  • the cargo handling vehicle 1 includes an attachment cylinder 15 (see FIG. 2) as an attachment hydraulic cylinder for operating an attachment (not shown).
  • an attachment for example, there is one that moves, tilts, and rotates the fork 6 left and right.
  • the cab 10 is provided with an attachment operation lever (not shown) for operating the attachment cylinder 15 to operate the attachment.
  • the cab 10 is provided with a direction switch for switching the traveling direction (forward / reverse / neutral) of the cargo handling vehicle 1.
  • FIG. 2 is a hydraulic circuit diagram showing a first embodiment of a hydraulic drive device according to the present invention.
  • a hydraulic drive device 16 of the present embodiment is a device that drives a lift cylinder 4, a tilt cylinder 9, an attachment cylinder 15, and a PS cylinder 14.
  • the hydraulic drive device 16 includes a single hydraulic pump motor 17 and a single electric motor 18 that drives the hydraulic pump motor 17.
  • the hydraulic pump motor 17 has a suction port 17a for sucking hydraulic oil and a discharge port 17b for discharging hydraulic oil.
  • the hydraulic pump motor 17 is configured to be rotatable in one direction.
  • the electric motor 18 functions as an electric motor or a generator. Specifically, when the hydraulic pump motor 17 operates as a hydraulic pump, the electric motor 18 functions as an electric motor, and when the hydraulic pump motor 17 operates as a hydraulic motor, the electric motor 18 functions as a generator. To do. When the electric motor 18 functions as a generator, the electric power generated by the electric motor 18 is stored in a battery (not shown). That is, a regenerative operation is performed.
  • a tank 19 for storing hydraulic oil is connected to the suction port 17a of the hydraulic pump motor 17 via a hydraulic pipe 20.
  • the hydraulic pipe 20 is provided with a check valve 21 for flowing hydraulic oil only in the direction from the tank 19 to the hydraulic pump motor 17.
  • the hydraulic pump motor 17 functions as a pump that supplies hydraulic oil to the lift cylinder 4 when the lift operation lever 11 is raised, and is driven by the hydraulic oil discharged from the lift cylinder 4 when the lift operation lever 11 is lowered. Functions as a hydraulic motor.
  • the discharge port 17 b of the hydraulic pump motor 17 and the bottom chamber 4 b of the lift cylinder 4 are connected via a hydraulic pipe 22.
  • the hydraulic piping 22 is provided with an electromagnetic proportional valve 23 for lifting the lift.
  • the electromagnetic proportional valve 23 has an open position 23 a that allows the hydraulic oil to flow from the hydraulic pump motor 17 to the bottom chamber 4 b of the lift cylinder 4, and the hydraulic oil flows from the hydraulic pump motor 17 to the bottom chamber 4 b of the lift cylinder 4. Is switched to the closed position 23b that shuts off.
  • the electromagnetic proportional valve 23 is normally in a closed position 23b (illustrated), and an operation signal (a lift raising solenoid current command value corresponding to an operation amount of the lifting operation of the lift operation lever 11) is input to the solenoid operating portion 23c. Then, it switches to the open position 23a. Then, hydraulic oil is supplied from the hydraulic pump motor 17 to the bottom chamber 4b of the lift cylinder 4, the lift cylinder 4 extends, and the fork 6 rises accordingly.
  • the electromagnetic proportional valve 23 is in the open position 23a, the electromagnetic proportional valve 23 is opened at an opening corresponding to the operation signal.
  • a check valve 24 is provided between the electromagnetic proportional valve 23 and the lift cylinder 4 in the hydraulic pipe 22 so that hydraulic fluid flows only in the direction from the electromagnetic proportional valve 23 to the lift cylinder 4.
  • a tilting proportional solenoid valve 26 is connected to a branch point between the hydraulic pump motor 17 and the proportional solenoid valve 23 in the hydraulic pipe 22 via a hydraulic pipe 25.
  • the hydraulic pipe 25 is provided with a check valve 27 that allows hydraulic oil to flow only in the direction from the hydraulic pump motor 17 to the electromagnetic proportional valve 26.
  • the electromagnetic proportional valve 26 and the rod chamber 9a and the bottom chamber 9b of the tilt cylinder 9 are connected via hydraulic pipes 28 and 29, respectively.
  • the electromagnetic proportional valve 26 has an open position 26 a that allows the hydraulic oil to flow from the hydraulic pump motor 17 to the rod chamber 9 a of the tilt cylinder 9, and the hydraulic oil flows from the hydraulic pump motor 17 to the bottom chamber 9 b of the tilt cylinder 9. Is switched between an open position 26b allowing the hydraulic oil and a closed position 26c interrupting the flow of the hydraulic oil from the hydraulic pump motor 17 to the tilt cylinder 9.
  • the electromagnetic proportional valve 26 is normally in a closed position 26c (illustrated), and an operation signal (a tilt solenoid current command value corresponding to an operation amount of a tilting operation of the tilt operation lever 12) is sent to a solenoid operation unit 26d on the open position 26a side. ) Is switched to the open position 26a, and an operation signal (tilt solenoid current command value corresponding to the amount of forward tilt operation of the tilt operation lever 12) is input to the solenoid operation portion 26e on the open position 26b side. If it does, it will switch to the open position 26b.
  • An electromagnetic proportional valve 31 for attachment is connected to the upstream side of the check valve 27 in the hydraulic pipe 25 via a hydraulic pipe 30.
  • the hydraulic pipe 30 is provided with a check valve 32 that circulates hydraulic oil only in the direction from the hydraulic pump motor 17 to the electromagnetic proportional valve 31.
  • the electromagnetic proportional valve 31 and the rod chamber 15a and the bottom chamber 15b of the attachment cylinder 15 are connected via hydraulic pipes 33 and 34, respectively.
  • the electromagnetic proportional valve 31 has an open position 31a that allows the hydraulic fluid to flow from the hydraulic pump motor 17 to the rod chamber 15a of the attachment cylinder 15, and the hydraulic fluid to flow from the hydraulic pump motor 17 to the bottom chamber 15b of the attachment cylinder 15. Is switched between an open position 31b that allows the hydraulic oil and a closed position 31c that blocks the flow of hydraulic oil from the hydraulic pump motor 17 to the attachment cylinder 15.
  • the electromagnetic proportional valve 31 is normally in a closed position 31c (illustrated), and an operation signal (attachment solenoid current command value corresponding to an operation amount of one side operation of the attachment operation lever) is sent to a solenoid operation unit 31d on the open position 31a side. Is switched to the open position 31a, and an operation signal (attachment solenoid current command value corresponding to the operation amount of the other operation of the attachment operation lever) is input to the solenoid operation portion 31e on the open position 31b side. And switch to the open position 31b. The operation of the attachment cylinder 15 is omitted. Further, when the electromagnetic proportional valve 31 is in the open positions 31a and 31b, the electromagnetic proportional valve 31 is opened at an opening corresponding to the operation signal.
  • An electromagnetic proportional valve 36 for PS is connected to the upstream side of the check valve 32 in the hydraulic pipe 30 via a hydraulic pipe 35.
  • the hydraulic pipe 35 is provided with a check valve 37 for flowing hydraulic oil only in the direction from the hydraulic pump motor 17 to the electromagnetic proportional valve 36.
  • the electromagnetic proportional valve 36 and the first rod chamber 14a and the second rod chamber 14b of the PS cylinder 14 are connected via hydraulic pipes 38 and 39, respectively.
  • the electromagnetic proportional valve 36 has an open position 36a that allows the hydraulic oil to flow from the hydraulic pump motor 17 to the first rod chamber 14a of the PS cylinder 14, and from the hydraulic pump motor 17 to the second rod chamber 14b of the PS cylinder 14.
  • the position is switched between an open position 36 b that allows the hydraulic oil to flow and a closed position 36 c that blocks the hydraulic oil flow from the hydraulic pump motor 17 to the PS cylinder 14.
  • the electromagnetic proportional valve 36 is normally in a closed position 36c (illustrated), and an operation signal (PS solenoid current command value corresponding to the operation speed of the left and right one side operation of the steering wheel 13) is sent to the solenoid operation unit 36d on the open position 36a side. Is switched to the open position 36a, and an operation signal (PS solenoid current command value corresponding to the operation speed of the left and right other side operation of the steering wheel 13) is input to the solenoid operating portion 36e on the open position 36b side. Then, it switches to the open position 36b. Note that the operation of the PS cylinder 14 is omitted.
  • the electromagnetic proportional valve 36 is in the open positions 36a and 36b, the electromagnetic proportional valve 36 is opened at an opening corresponding to the operation signal.
  • the branch point between the hydraulic pump motor 17 and the electromagnetic proportional valve 23 in the hydraulic pipe 22 is connected to the tank 19 via the hydraulic pipe 40.
  • the hydraulic pipe 40 is provided with an unload valve 41 and a filter 42.
  • the hydraulic piping 40 and the electromagnetic proportional valves 26, 31, 36 are connected via hydraulic piping 43-45. Further, the electromagnetic proportional valves 23, 26, 31, 36 are connected to the hydraulic pipe 40 via the hydraulic pipe 46.
  • the suction port 17 a of the hydraulic pump motor 17 and the bottom chamber 4 b of the lift cylinder 4 are connected via a hydraulic pipe (first hydraulic fluid passage) 47.
  • the hydraulic piping 47 is connected to the bottom chamber 4b of the lift cylinder 4 and the hydraulic pump motor 17 so that the hydraulic oil discharged from the lift cylinder 4 flows to the suction port 17a of the hydraulic pump motor 17 when the lift operation lever 11 is operated alone.
  • the hydraulic pipe 47 is provided with an electromagnetic proportional valve 48 for lowering the fork.
  • the electromagnetic proportional valve 48 includes an open position 48 a that allows the hydraulic oil to flow from the bottom chamber 4 b of the lift cylinder 4 to the suction port 17 a of the hydraulic pump motor 17, and the suction of the hydraulic pump motor 17 from the bottom chamber 4 b of the lift cylinder 4. It is switched between a closed position 48b that blocks the flow of hydraulic oil to the port 17a.
  • the electromagnetic proportional valve 48 is normally in a closed position 48b (illustrated), and an operation signal (a solenoid current command value for fork lowering according to an operation amount of the lowering operation of the lift operation lever 11) is input to the solenoid operating portion 48c. Then, it switches to the open position 48a. Then, the fork 6 descends due to the weight of the fork 6, and the lift cylinder 4 contracts accordingly, and hydraulic oil flows out from the bottom chamber 4 b of the lift cylinder 4. When the electromagnetic proportional valve 48 is in the open position 48a, the electromagnetic proportional valve 48 is opened at an opening corresponding to the operation signal.
  • an operation signal a solenoid current command value for fork lowering according to an operation amount of the lowering operation of the lift operation lever 11
  • a branch point 91 between the hydraulic pump motor 17 and the electromagnetic proportional valve 48 in the hydraulic pipe 47 is connected to the tank 19 via a hydraulic pipe (second hydraulic oil flow path) 49.
  • the hydraulic pipe 49 is provided with a bypass flow control valve (first flow control valve) 50.
  • the bypass flow control valve 50 controls the flow rate of the hydraulic oil that returns from the lift cylinder 4 to the tank 19.
  • the hydraulic pipe 49 is provided with a filter 54.
  • the bypass flow control valve 50 is switched between an open position 50a that allows the flow of hydraulic fluid, a closed position 50b that blocks the flow of hydraulic fluid, and a throttle position 50c that adjusts the flow rate of hydraulic fluid.
  • the pilot operating part on the closed position 50 b side of the bypass flow control valve 50 and the upstream side (front side) of the electromagnetic proportional valve 48 are connected via a pilot flow path 51.
  • the pilot operating part on the open position 50 a side of the bypass flow control valve 50 and the downstream side (rear side) of the electromagnetic proportional valve 48 are connected via a pilot flow path 52.
  • the bypass flow control valve 50 opens at an opening corresponding to the pressure difference before and after the electromagnetic proportional valve 48.
  • the bypass flow control valve 50 is in the closed position at the normal time when the electromagnetic proportional valve 48 is closed.
  • the bypass flow control valve 50 opens at an opening degree corresponding to the pressure difference before and after the electromagnetic proportional valve 48.
  • the opening degree of the bypass flow control valve 50 becomes larger.
  • the bypass flow control valve 50 opens. The degree becomes smaller.
  • a regenerative flow control valve (second flow control valve) 80 is disposed between the suction port 17a of the hydraulic pump motor 17 and the branch point 91.
  • the regenerative flow control valve 80 controls the flow rate of the hydraulic fluid flowing from the lift cylinder 4 to the hydraulic pump motor 17.
  • the regenerative flow control valve 80 is switched between an open position 80a that allows the flow of hydraulic fluid, a closed position 80b that blocks the flow of hydraulic fluid, and a throttle position 80c that adjusts the flow rate of hydraulic fluid.
  • the pilot operating portion on the closed position 80 b side of the regenerative flow control valve 80 and the upstream side (front side) of the electromagnetic proportional valve 48 are connected via a pilot flow path 81.
  • the pilot operating portion on the open position 80 a side of the regenerative flow control valve 80 and the downstream side (rear side) of the electromagnetic proportional valve 48 are connected via a pilot flow path 82.
  • the regenerative flow control valve 80 opens at an opening corresponding to the pressure difference before and after the electromagnetic proportional valve 48. Specifically, the regenerative flow control valve 80 is in the closed position at the normal time when the electromagnetic proportional valve 48 is closed. When the electromagnetic proportional valve 48 is opened, the regenerative flow control valve 80 is opened at an opening corresponding to the pressure difference before and after the electromagnetic proportional valve 48.
  • the opening degree of the regenerative flow control valve 80 increases, and as the pressure difference before and after the electromagnetic proportional valve 48 increases, the regenerative flow control valve 80 opens. The degree becomes smaller.
  • second hydraulic cylinder 70 the tilt operation lever 12, the steering wheel 13, and the attachment operation lever, which are levers for operating the second hydraulic cylinder 70, may be collectively referred to as a “second operation unit 73”.
  • FIG. 3 is a configuration diagram showing a control system of the hydraulic drive device 16.
  • a hydraulic drive device 16 includes a lift operation lever operation amount sensor (operation amount detection unit) 55 that detects an operation amount of the lift operation lever 11 and a tilt operation lever operation amount that detects an operation amount of the tilt operation lever 12.
  • a rotation speed sensor 59 for detecting the actual rotation speed of the motor) and a controller 60 are provided.
  • the controller 60 inputs detection values of the operation lever operation amount sensors 55 to 57, the steering operation speed sensor 58, and the rotation speed sensor 59, performs a predetermined process, and performs the electric motor 18, the electromagnetic proportional valves 23, 26, 31, 36. , 48 are controlled.
  • the sensors 56, 57, and 58 that detect the operation amount of the second operation unit 73 may be referred to as “second operation amount detection unit 71”.
  • electromagnetic proportional valves 26, 31, 36 that are disposed between the discharge port 17 b of the hydraulic pump motor 17 and the second hydraulic cylinder and control the flow of the hydraulic oil based on the operation of the second operation unit 73 are provided. It may be referred to as “second control valve 72”.
  • FIG. 4 is a block configuration diagram showing a block configuration of a control system of the hydraulic drive device 16.
  • the controller 60 includes a motor driver 61, a power running torque limit control target rotational speed calculation unit 66, a motor command rotational speed calculation unit 67, and a determination unit 69.
  • the motor driver 61 includes comparison units 62A and 62B, a PID calculation unit 63, a power running torque limit value calculation unit 68, an output torque determination unit (control unit) 64, and a motor control unit (control unit) 65. ing.
  • the comparison unit 62A calculates a rotational speed deviation between the motor command rotational speed set by the motor command rotational speed calculation unit 67 and the actual motor rotational speed detected by the rotational speed sensor 59.
  • the comparison unit 62B calculates a rotational speed deviation between the power running torque limit control target rotational speed set by the power running torque limit control target rotational speed calculation unit 66 and the actual motor rotational speed detected by the rotational speed sensor 59.
  • the PID calculation unit 63 performs a PID calculation of a rotation speed deviation between the motor command rotation speed and the motor actual rotation speed, and obtains a power running torque command value of the electric motor 18 such that the rotation speed deviation becomes zero.
  • the PID calculation is a combination of a proportional operation, an integral operation, and a derivative operation.
  • the power running torque limit value calculation unit 68 calculates the power running torque limit value of the electric motor 18 based on the rotation speed deviation between the power running torque limit control target rotation speed and the actual motor rotation speed detected by the rotation speed sensor 59. Set.
  • the power running torque limit value is a value for limiting the output torque so as not to increase when the output torque of the electric motor 18 moves toward the power running side.
  • the power running torque limit value set by the power running torque limit value calculation unit 68 will be described in detail.
  • the output torque determination unit 64 and the motor control unit 65 constituting the control unit control the electric motor 18 so that the rotation speed is based on the motor command rotation speed (rotation speed command value), and the output torque of the electric motor 18 is power running.
  • the electric motor 18 is controlled so that the rotational speed is based on the power running torque limit value.
  • the output torque determination unit 64 is a power running torque command value (a value based on the motor command rotational speed) obtained by the PID calculation unit 63 and a power running torque of the electric motor 18 set by the power running torque limit value calculation unit 68.
  • the output torque of the electric motor 18 is determined by comparing with the limit value.
  • the power running torque command value when the power running torque command value is less than or equal to the power running torque limit value, the power running torque command value is set as the output torque of the electric motor 18, and when the power running torque command value is higher than the power running torque limit value, the power running torque limit is set.
  • the value is the output torque of the electric motor 18.
  • the motor control unit 65 converts the output torque determined by the output torque determination unit 64 into a current signal and sends it to the electric motor 18.
  • the bypass flow control valve 50 is connected via the hydraulic pipe 49. The hydraulic oil is discharged to the tank 19.
  • the motor command rotation speed calculation unit 67 acquires detection values detected by the sensors 55, 56, 57, and 58, and sets a motor command rotation speed (rotation speed command value) based on the detection values.
  • the motor command rotation speed calculation unit 67 sets the motor command rotation speed according to the operation amount of each operation lever.
  • the motor command rotational speed set by the motor command rotational speed calculation unit 67 will be described in detail.
  • the power running torque limit control target rotational speed calculation unit 66 acquires the detection values detected by the sensors 55, 56, 57, and 58, and sets the power running torque limit control target rotational speed based on the detected values.
  • the power running torque limit control target rotational speed calculation unit 66 sets the power running torque limit control target rotational speed according to the operation state of each operation lever.
  • the determination unit 69 determines whether the lowering operation of the lift operation lever 11 is performed alone and whether the operation of the second operation unit 73 including the lowering operation of the lift operation lever 11 is performed simultaneously. For example, when the fork lowering + tilt operation, the fork lowering + attachment operation, the fork lowering + power steering operation, and the fork lowering + tilt + power steering operation are performed, the determination unit 69 includes the second operation unit including the lift operation lever 11. It is determined that the operations 73 are performed simultaneously. The determination unit 69 outputs the determination result to the motor command rotational speed calculation unit 67 and the power running torque limit value calculation unit 68.
  • FIG. 5 is a flowchart showing a control processing procedure executed by the controller 60.
  • this control process only the operation including the lowering of the fork 6 (fork lowering) is targeted.
  • the period for executing this control process is appropriately determined by experiments or the like.
  • the fork lowering mode as the operation condition is determined based on the operation amount of the lift operation lever 11, the tilt operation lever 12, the attachment operation lever and the operation speed of the steering wheel 13 acquired in step S101 (step S102).
  • Fork lowering modes include fork lowering single operation, fork lowering + tilt operation, fork lowering + attachment operation, fork lowering + power steering operation, fork lowering + tilt + power steering operation.
  • the solenoid proportional valve solenoid current command value includes a fork lowering solenoid current command value corresponding to the operation amount of the lowering operation of the lift operation lever 11, a tilt solenoid current command value corresponding to the operation amount of the tilt operation lever 12, and an attachment operation.
  • the required rotational speed includes a lift required motor speed, a tilt required motor speed, an attachment required motor speed, and a power steering (PS) required motor speed.
  • the lift required motor rotation speed is the rotation speed of the electric motor 18 necessary for performing the lift operation.
  • the tilt required motor rotational speed is the rotational speed of the electric motor 18 necessary for performing the tilt operation.
  • the attachment-required motor rotational speed is the rotational speed of the electric motor 18 necessary for performing the attachment operation.
  • the PS required motor rotational speed is the rotational speed of the electric motor 18 necessary for performing the PS operation.
  • the motor command rotational speed calculation unit 67 sets a motor rotational speed command value (motor command rotational speed) based on the fork lowering mode determined in step S102 and the necessary rotational speed obtained in step S104 ( Procedure S105). At this time, the motor command rotational speed is set based on the above-described FIG.
  • the power running torque limit value of the electric motor 18 is set based on the fork lowering mode determined in step S102 (step S106).
  • the power running torque limit value is an allowable power running torque value.
  • the power running torque limit value calculation unit 68 is set based on the above-described FIG.
  • step S106 the electromagnetic proportional valve solenoid current command value obtained in step S103 is sent to the solenoid operation unit of the corresponding electromagnetic proportional valve (step S107). At this time, the fork lowering solenoid current command value is sent to the solenoid operating portion 48 c of the electromagnetic proportional valve 48.
  • the current command value is sent to either of the solenoid operating portions 26d and 26e of the electromagnetic proportional valve 26, and when the attachment solenoid current command value is obtained.
  • the current command value is sent to one of the solenoid operating portions 31d and 31e of the electromagnetic proportional valve 31 and the PS solenoid current command value is obtained, the current command value is sent to the solenoid operating portions 36d and 36e of the electromagnetic proportional valve 36.
  • step S105 the motor rotational speed command value (motor command rotational speed) set in step S105, the actual motor rotational speed detected by the rotational speed sensor 59, and the power running torque limit value of the electric motor 18 set in step S106 are obtained. Based on this, the output torque of the electric motor 18 is obtained, and the output torque is sent to the electric motor 18 as a control signal (step S108).
  • step S108 is executed by a motor driver 61 included in the controller 60 as shown in FIG.
  • FIG. 6A is a graph showing the relationship between the lowering operation amount and the motor rotation speed.
  • the horizontal axis of FIG. 6A is the operation amount of the lift operation lever 11 (hereinafter referred to as the downward operation amount), and the vertical axis indicates the motor rotation speed of the electric motor 18.
  • the motor rotation speed is equivalent to the pump rotation speed of the hydraulic pump motor 17 and is a value corresponding to the opening of the descending electromagnetic proportional valve 48.
  • a direct proportional relationship is established between the lowering operation amount and the motor speed (that is, the opening degree of the electromagnetic proportional valve 48 for lowering).
  • FIG. 6B is a graph showing the relationship between the motor speed and the cylinder flow rate.
  • the horizontal axis of FIG. 6B indicates the motor rotation speed of the electric motor 18 and may be regarded as being equivalent to the pump rotation speed of the hydraulic pump motor 17.
  • the vertical axis in FIG. 6B is the cylinder flow rate of the lift cylinder 4 and may be regarded as a value corresponding to the fork lowering speed.
  • the graph L1 indicating the characteristics when the lowering operation amount is “large”
  • the graph L2 indicating the characteristics when the lowering operation amount is “medium”
  • the lowering operation amount A graph L3 showing characteristics in the case of “small” is shown.
  • the control is performed so that the cylinder flow rate, that is, the fork lowering speed increases as the lowering operation amount increases.
  • the operation amount can be set steplessly by the driver's lever operation.
  • FIG. 6B for the sake of explanation, “large”, “medium”, and “small” are used.
  • the three-stage case is taken as an example.
  • FIG. 6B shows a graph LP indicating the relationship between the motor rotation speed (pump rotation speed) and the pump flow rate of the hydraulic pump motor 17.
  • a direct proportional relationship is established between the motor rotation speed and the pump flow rate of the hydraulic pump motor 17.
  • the motor rotation speed command value for each lowering operation amount is set to P1, P2, and P3 on the graph LP, respectively.
  • the bypass flow control valve 50 controls the flow rate of the hydraulic oil (discharges the hydraulic oil to the tank 19). If not, the motor rotation speed and cylinder flow rate are the values at “P1”.
  • the flow rate control by the bypass flow control valve 50 is performed in the region E1 where the motor rotation speed is more negative than the graph LP (left side of the drawing). That is, in the graphs L1, L2, and L3, the flow control by the bypass flow control valve 50 is performed in the graphs L1a, L2a, and L3a on the region E1 side. At this time, the regenerative flow control valve 80 is in an “open” state. In the region E1, as shown in the graphs L1a, L2a, and L3a, the flow rate of the hydraulic oil discharged by the bypass flow control valve 50 so that the cylinder flow rate (that is, the fork lowering speed) becomes constant according to the lowering operation amount. To control.
  • the motor rotational speed in the state where the lowering operation amount is “large” and the single lowering operation is performed is “P1”, and the state shifts from this state to the simultaneous operation of the second hydraulic cylinder 70 and the motor rotational speed is “P1”. “R1” smaller than “”.
  • the opening degree of the regenerative flow control valve 80 becomes larger and the opening degree of the bypass flow control valve 50 becomes larger, so that a part of the cylinder flow rate is reduced. It is discharged to the tank 19 via the bypass flow control valve 50.
  • hydraulic oil corresponding to the flow rate indicated by “V 1” between the graph L 1 a and the pump flow rate graph LP is discharged to the tank 19 by the bypass flow control valve 50.
  • regeneration is performed by the hydraulic oil relating to the flow rate indicated by “V2” in the graph LP flowing into the suction port 17a of the hydraulic pump motor 17.
  • the flow rate control by the regenerative flow rate control valve 80 is performed in the region E2 in which the motor rotational speed is on the positive side (right side of the drawing) from the graph LP. That is, in the graphs L1, L2, L3, the flow rate control by the regenerative flow control valve 80 is performed in the graphs L1b, L2b, L3b and the graphs L1c, L2c, L3c on the region E2 side.
  • the bypass flow control valve 50 at this time is in a “closed” state.
  • the regenerative flow control valve 80 causes the suction of the hydraulic pump motor 17 so that the cylinder flow rate (that is, the fork lowering speed) becomes constant according to the lowering operation amount.
  • the flow rate of the hydraulic oil flowing to the port 17a is controlled.
  • the difference between the pump flow rate corresponding to the motor rotation speed and the cylinder flow rate kept constant is that the hydraulic pump motor 17 pulls the hydraulic oil from the tank 19 via the hydraulic pipe 20. It is supplemented by that. Therefore, regeneration does not occur in the graphs L1c, L2c, and L3c.
  • the cylinder flow rate (that is, the fork lowering speed) in the graphs L1c, L2c, and L3c is set higher than the cylinder flow rate (that is, the fork lowering speed) in the graphs L1a, L2a, and L3a. That is, the flow rate of the hydraulic oil that can be controlled by the regenerative flow control valve 80 is set to be larger than the flow rate of the hydraulic oil that can be controlled by the bypass flow control valve.
  • the degree of throttling of the regenerative flow control valve 80 is adjusted so that the cylinder flow rate slightly rises along the pump flow rate graph LP as the motor rotation speed increases. Regeneration occurs in the graphs L1b, L2b, and L3c.
  • the portions of the graphs L1b, L2b, and L3b function as a buffer unit when shifting from the flow control by the bypass flow control valve 50 to the flow control by the regenerative flow control valve 80.
  • the motor rotational speed increases and the region E2 side control is performed.
  • the motor rotational speed in the state where the lowering operation amount is “large” and the single lowering operation is performed is “P1”, and from this state, the second hydraulic cylinder 70 is operated simultaneously and the motor rotational speed is “P1”. It is assumed that “R2” is larger than that.
  • the control units 64 and 65 set the power running torque limit control target rotational speed to be close to 0 rpm and perform the power running torque limit control.
  • “rotational speed deviation power running torque limit control target rotational speed ⁇ actual rotational speed” is set, and the power running torque limit value output is determined so that the rotational speed deviation becomes zero.
  • FIG. 7 three patterns of control forms are shown. In any form, such a power running torque limit control is performed at the time of the single operation of the fork lowering operation (hereinafter simply referred to as “single operation”).
  • FIG. 7 shows a case where the “other required rotational speed” required for operating other actuators other than the fork at a desired speed is smaller than the “required rotational speed required for lowering the fork at the desired speed”. Show.
  • the upper graph in FIG. 7 shows a state where the load is large (high load state) and sufficient regeneration can be performed.
  • the lower graph of FIG. 7 shows a state where the load is small (low load state) and sufficient regeneration cannot be performed.
  • the controller 60 turns on the power running torque limit control when the fork lowering operation is performed alone, and sets the command rotation speed of the electric motor 18 to the power running torque limit target rotation speed.
  • the command rotational speed of the electric motor 18 is the required rotational speed and the second hydraulic cylinder 70. Is set to a higher one (represented by “other required rotation number”). Further, the power running torque limit control is set to OFF (power running is 100% permitted). As shown in the upper graph of FIG.
  • the hydraulic oil discharged from the lift cylinder 4 is electrically operated during the single operation for performing the fork lowering operation alone. Regeneration is performed with the actual rotational speed of the motor 18 being the required rotational speed. Further, when the operation is shifted from the single operation to the simultaneous operation in a high load state, the actual rotational speed of the electric motor 18 is controlled to the revolving required rotational speed, regeneration is performed, and the hydraulic oil discharged from the lift cylinder 4 As a result, the hydraulic pump motor 17 is driven and hydraulic oil is supplied to the second hydraulic cylinder 70. That is, in this case, regeneration and other actuator operations can be performed by effectively using the energy of the load.
  • the power running torque limit control is turned off, so that the electric motor 18 is powered and the actual rotational speed of the electric motor 18 is reduced to the required rotational speed (other necessary rotational speeds). Higher than the number).
  • the opening degree of the bypass flow control valve 50 is controlled to an opening degree corresponding to the pressure difference of the electromagnetic proportional valve 48, and a part of the hydraulic oil discharged from the lift cylinder 4 is bypassed to the tank 19.
  • the controller 60 turns on the power running torque limit control when the fork lowering operation is performed alone, and sets the command rotation speed of the electric motor 18 to the power running torque limit target rotation speed.
  • the command rotational speed of the electric motor 18 is set to the necessary rotational speed of the second hydraulic cylinder 70 (other necessary rotational speed).
  • the power running torque limit control is set to OFF (power running is 100% permitted).
  • regeneration is performed with the actual rotational speed of the electric motor 18 being the required rotational speed at the time of single operation at a high load.
  • regeneration is performed by controlling the actual rotational speed of the electric motor 18 to other required rotational speed that is smaller than the required rotational speed, and the electric motor 18 is driven by hydraulic oil discharged from the lift cylinder 4.
  • the hydraulic oil is supplied to the second hydraulic cylinder via the hydraulic pump motor 17.
  • the pressure difference before and after the electromagnetic proportional valve 48 is reduced, so that the degree of opening of the bypass flow control valve 50 is increased, and a part of the hydraulic oil discharged from the lift cylinder 4 is bypassed. It is discharged to the tank 19 through the control valve 50.
  • the actual rotational speed of the electric motor 18 does not increase to the required rotational speed during the single operation with a low load.
  • the controller 60 turns on the power running torque limit control when the fork lowering operation is performed alone, and sets the command rotation speed of the electric motor 18 to the power running torque limit target rotation speed.
  • the command rotational speed of the electric motor 18 is equal to the required rotational speed of the lowering and the required rotational speed of the second hydraulic cylinder 70 (other required rotational speed).
  • the power running torque limit control is set to ON.
  • the power running torque limit control target rotational speed is set to a necessary rotational speed of the second hydraulic cylinder 70 (other necessary rotational speed). As shown in the upper graph of FIG.
  • the actual rotational speed of the electric motor 18 is increased to the required rotational speed for reduction, and regeneration is performed. Further, at the same time when the high load is operated, the actual rotational speed of the electric motor 18 is controlled to the revolving required rotational speed to perform regeneration, and the hydraulic pump motor 17 is driven by the hydraulic oil discharged from the lift cylinder 4 to 2 Hydraulic oil is supplied to the hydraulic cylinder 70. As shown in the lower graph of FIG. 7C, the actual rotational speed of the electric motor 18 does not increase to the required rotational speed during the single operation with a low load.
  • the actual rotational speed of the electric motor 18 is controlled to the other necessary rotational speed, and regeneration is performed. Further, the hydraulic pump motor 17 is driven by the hydraulic oil discharged from the lift cylinder 4 and the hydraulic oil is supplied to the second hydraulic cylinder 70. As shown in the lower graph of FIG. 8, during the single operation in the low load state, the energy of the hydraulic oil discharged from the lift cylinder 4 is small, and the actual rotational speed of the electric motor 18 does not increase to the required rotational speed.
  • the opening degree of the bypass flow control valve 50 becomes larger, and much of the hydraulic oil discharged from the lift cylinder 4 passes through the bypass flow control valve 50. And discharged to the tank 19. Further, when shifting from the single operation to the simultaneous operation in the low load state, the actual rotational speed of the electric motor 18 becomes the other necessary rotational speed (higher than the descending necessary rotational speed) in any control. At this time, the opening degree of the bypass flow control valve 50 is controlled to an opening degree corresponding to the pressure difference of the electromagnetic proportional valve 48, and a part of the hydraulic oil discharged from the lift cylinder 4 is bypassed to the tank 19.
  • a hydraulic pipe 49 is connected via a branch point 91 from a hydraulic pipe 47 for sending hydraulic oil from the lift operation lever 11 to the hydraulic pump motor 17. .
  • a bypass flow control valve 50 for controlling the flow rate of the hydraulic oil returning from the lift operation lever 11 to the tank 19 is disposed on the hydraulic pipe 49.
  • a regenerative flow control valve 80 that controls the flow rate of the hydraulic oil flowing from the lift operation lever 11 to the hydraulic pump motor 17 is provided between the suction port 17 a of the hydraulic pump motor 17 and the branch point 91. It is arranged.
  • the motor rotation speed of the electric motor 18 connected to the hydraulic pump motor 17 is higher than the motor rotation speed corresponding to the operation amount of the lowering operation of the lift operation lever 11.
  • the bypass flow control valve 50 returns the hydraulic oil from the lift operation lever 11 to the tank 19, whereby the fork lowering speed corresponding to the operation amount of the lowering operation can be obtained.
  • the lowering operation and the operation of the other hydraulic cylinder are performed simultaneously (and the required rotation speed of the other hydraulic cylinder is larger than the required rotation speed of the other hydraulic cylinder), so that the motor rotation speed is increased compared with the single lowering operation.
  • the regenerative flow control valve 80 controls the hydraulic oil flow from the lift operation lever 11 to the hydraulic pump motor 17 so as to lower the fork.
  • the rapid increase in speed can be suppressed.
  • the other actuators can be operated at a desired speed and the lifted object lift can be lowered at the desired lowering speed. it can.
  • the required rotational speed for lowering is greater than the required rotational speed for other hydraulic cylinders, it is possible to operate other hydraulic cylinders using the load load energy. As a result, energy saving can be achieved.
  • the flow rate of the hydraulic fluid that can be controlled by the regenerative flow control valve 80 is set to be larger than the flow rate of the hydraulic fluid that can be controlled by the bypass flow control valve 50. ing. Accordingly, when the fork descending speed is kept constant by controlling the regenerative flow control valve 80 with respect to a predetermined lowering operation amount (the portions of the graphs L1c, L2c, and L3c in FIG. 6), the bypass flow control valve 50 is used. As compared with the case where the fork descending speed is kept constant by the control (the portions of the graphs L1a, L2a, L3a in FIG.
  • the fork descending speed by the control of the regenerative flow control valve 80 can be made higher. .
  • the transition from the control by the bypass flow control valve 50 to the control by the regenerative flow control valve 80 is performed.
  • Graphs L1b, L2b, and L3b shown in FIG. 6) can be provided.
  • the regenerative flow control valve 80 controls the flow rate of the hydraulic oil based on the pressure difference before and after the electromagnetic proportional valve 48. Thereby, the regenerative flow control valve can be controlled at a fork lowering speed corresponding to the operation amount of the lowering operation.
  • the bypass flow control valve 50 controls the flow rate of the hydraulic oil based on the pressure difference before and after the electromagnetic proportional valve 48. Thereby, the regenerative flow control valve can be controlled at a fork lowering speed corresponding to the operation amount of the lowering operation.
  • a tilt cylinder, a PS cylinder, and an attachment cylinder are provided as the second hydraulic cylinder.
  • at least one second hydraulic cylinder may be provided, and a part thereof may be omitted.
  • the attachment and the power steering are mounted, but the hydraulic drive device of the present invention can be applied to a forklift that is not mounted with the attachment and the power steering.
  • the hydraulic drive device of the present invention is applicable to any battery-type cargo handling vehicle other than a forklift.
  • SYMBOLS 1 Cargo handling vehicle, 4 ... Lift cylinder (hydraulic cylinder), 6 ... Fork (lifting object), 11 ... Lift operation lever (1st operation part), 16 ... Hydraulic drive device, 17 ... Hydraulic pump motor (hydraulic pump), 17a ... Suction port, 17b ... Discharge port, 18 ... Electric motor, 47 ... Hydraulic piping (first hydraulic fluid flow path), 48 ... Electromagnetic proportional valve (electromagnetic proportional valve) for fork lowering, 49 ... Hydraulic piping (first Hydraulic fluid flow), 50 ... bypass flow control valve (first flow control valve), 70 ... second hydraulic cylinder, 73 ... second operating portion, 80 ... regenerative flow control valve.

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Abstract

This hydraulic drive device is equipped with: a first hydraulic oil flow path for connecting the suction opening of a hydraulic pump to a first hydraulic cylinder, and feeding the hydraulic oil from the first hydraulic cylinder to the hydraulic pump; a second hydraulic oil flow path for connecting a branch point on the first hydraulic oil flow path to a tank, and returning the hydraulic oil from the first hydraulic cylinder to the tank; a first flow rate control valve which is disposed on the second hydraulic oil flow path, and controls the flow rate of the hydraulic oil returned from the first hydraulic cylinder to the tank; and a second flow rate control valve which is disposed between the suction opening of the hydraulic pump and the branch point on the first hydraulic oil flow path, and controls the flow rate of the hydraulic oil flowing from the first hydraulic cylinder to the hydraulic pump. If the descending operation of a first operation unit and the operation of a second operation unit are simultaneously performed while the rotational speed of a motor is increased and the flow rate of the hydraulic pump becomes higher than in the cases when the first operation unit is independently operated, the second flow rate control valve implements control so that the flow rate of the hydraulic oil flowing from the first hydraulic cylinder to the hydraulic pump is minimized.

Description

荷役車両の油圧駆動装置Hydraulic drive device for cargo handling vehicle
　本発明は、荷役車両の油圧駆動装置に関するものである。 The present invention relates to a hydraulic drive device for a cargo handling vehicle.
　荷役車両の油圧駆動装置として、例えば特許文献１に記載されているものが知られている。特許文献１に記載の油圧駆動装置は、作動油の給排により昇降物を昇降させる昇降用油圧シリンダと、昇降用油圧シリンダを作動させるための昇降操作部と、昇降用油圧シリンダ及び他のアクチュエータに係る油圧シリンダに対する作動油の給排を行う１つの油圧ポンプと、油圧ポンプを駆動する電動機と、油圧ポンプの吸込口と昇降用油圧シリンダのボトム室との間に配設され、昇降操作部の下降操作の操作量に基づいて作動油の流れを制御する制御弁と、を備えている。 As a hydraulic drive device for a cargo handling vehicle, for example, one described in Patent Document 1 is known. The hydraulic drive device described in Patent Document 1 includes a lifting hydraulic cylinder that lifts and lowers a lifting object by supplying and discharging hydraulic oil, a lifting operation unit for operating the lifting hydraulic cylinder, a lifting hydraulic cylinder, and other actuators. A hydraulic pump that supplies and discharges hydraulic oil to and from the hydraulic cylinder, an electric motor that drives the hydraulic pump, a suction port of the hydraulic pump, and a bottom chamber of the lifting hydraulic cylinder; And a control valve that controls the flow of hydraulic oil based on the operation amount of the lowering operation.
米国特許第５６４９４２２号明細書US Pat. No. 5,649,422
　ここで、上述のような従来の油圧駆動装置においては、以下の問題点が存在する。すなわち、油圧駆動装置は、昇降用油圧シリンダの下降操作が単独で行われる場合と、昇降用油圧シリンダの下降操作と他のアクチュエータに係る油圧シリンダの操作が同時に行われる場合がある。昇降用油圧シリンダの下降操作と他の油圧シリンダの操作が同時に行われる場合において、他のアクチュエータを所望の速度で動作させることができるように電動機の回転数を制御すると、昇降物の下降速度が所望の速度よりも早くなったり遅くなったりしてしまうという虞があった。従って、昇降用油圧シリンダの下降操作と他の油圧シリンダの操作が同時に行われる場合に、昇降物を所望の下降速度で下降させることができるように電動機の回転数を制御することが要請されていた。 Here, the following problems exist in the conventional hydraulic drive apparatus as described above. That is, in the hydraulic drive device, there are a case where the lowering operation of the lifting hydraulic cylinder is performed alone and a case where the lowering operation of the lifting hydraulic cylinder and the operation of the hydraulic cylinders related to other actuators are performed simultaneously. In the case where the lowering operation of the lifting hydraulic cylinder and the operation of other hydraulic cylinders are performed at the same time, if the motor speed is controlled so that the other actuators can be operated at a desired speed, the lowering speed of the lifting object is reduced. There was a possibility that it would be faster or slower than the desired speed. Therefore, when the lowering operation of the lifting hydraulic cylinder and the operation of other hydraulic cylinders are performed simultaneously, it is required to control the rotation speed of the electric motor so that the lifting object can be lowered at a desired lowering speed. It was.
　本発明の目的は、昇降用の油圧シリンダの下降操作と他の油圧シリンダの操作が同時に行われる場合に、昇降物を所望の下降速度で下降させることができる荷役車両の油圧駆動装置を提供することである。 An object of the present invention is to provide a hydraulic drive device for a cargo handling vehicle capable of lowering an ascending / descending object at a desired lowering speed when a lowering operation of a lifting hydraulic cylinder and an operation of another hydraulic cylinder are performed simultaneously. That is.
　本発明の一側面に係る荷役車両の油圧駆動装置は、作動油の給排により昇降物を昇降させる昇降用の第１油圧シリンダと、作動油の給排により第１油圧シリンダと異なる動作を行う第２油圧シリンダと、第１油圧シリンダを作動させるための第１操作部と、第２油圧シリンダを作動させるための第２操作部と、第１油圧シリンダ及び第２油圧シリンダに対する作動油の給排を行う油圧ポンプと、油圧ポンプに接続されて、電動機または発電機として機能する電動モータと、作動油を貯留するタンクと、油圧ポンプの吸込口と第１油圧シリンダとを接続し、第１油圧シリンダからの作動油を油圧ポンプに送るための第１作動油流路と、第１作動油流路上の分岐点とタンクとを接続し、第１油圧シリンダからの作動油をタンクに戻すための第２作動油流路と、第２作動油流路上に配設され、第１油圧シリンダからタンクに戻る作動油の流量を制御する第１流量制御弁と、第１作動油流路において、油圧ポンプの吸込口と分岐点との間に配設され、第１油圧シリンダから油圧ポンプへ流れる作動油の流量を制御する第２流量制御弁と、を備え、第１操作部による下降操作と第２操作部の操作が同時に行われる際に、第１操作部の単独操作時よりもモータ回転数が上昇して油圧ポンプの流量が多くなる場合、第２流量制御弁が第１油圧シリンダから油圧ポンプへ向かう作動油の流量を抑えるように制御する。 A hydraulic drive device for a cargo handling vehicle according to one aspect of the present invention performs a first hydraulic cylinder for raising and lowering a lifted object by supplying and discharging hydraulic oil and an operation different from that of the first hydraulic cylinder by supplying and discharging hydraulic oil. The second hydraulic cylinder, the first operating part for operating the first hydraulic cylinder, the second operating part for operating the second hydraulic cylinder, and the supply of hydraulic oil to the first hydraulic cylinder and the second hydraulic cylinder A hydraulic pump that discharges, an electric motor that is connected to the hydraulic pump and functions as an electric motor or a generator, a tank that stores hydraulic oil, a suction port of the hydraulic pump, and a first hydraulic cylinder are connected to each other; A first hydraulic fluid passage for sending hydraulic fluid from the hydraulic cylinder to the hydraulic pump, a branch point on the first hydraulic fluid passage, and a tank are connected, and the hydraulic fluid from the first hydraulic cylinder is returned to the tank. Second of A hydraulic flow path, a first flow rate control valve disposed on the second hydraulic oil path and controlling the flow rate of the hydraulic oil returning from the first hydraulic cylinder to the tank; A second flow rate control valve that is disposed between the suction port and the branch point and controls the flow rate of the hydraulic fluid flowing from the first hydraulic cylinder to the hydraulic pump, and the lowering operation and the second operation by the first operation unit When the motor operation speed is increased and the flow rate of the hydraulic pump increases as compared to when the first operation unit is operated alone, the second flow rate control valve is moved from the first hydraulic cylinder to the hydraulic pump. Control to reduce the flow rate of the working fluid.
　本発明の一側面に係る荷役車両の油圧駆動装置において、第１油圧シリンダからの作動油を油圧ポンプに送るための第１作動油流路から分岐点を介して第２作動油流路が接続されている。当該第２作動油流路上には、第１油圧シリンダからタンクに戻る作動油の流量を制御する第１流量制御弁が配設されている。また、第１作動油流路において、油圧ポンプの吸込口と分岐点との間には、第１油圧シリンダから油圧ポンプへ流れる作動油の流量を制御する第２流量制御弁が配設されている。このような構成によれば、第１操作部による下降操作と第２操作部の操作が同時に行われることで、第１操作部の単独操作時よりもモータ回転数が上がり、油圧ポンプの流量が上がる場合、第２流量制御弁が第１油圧シリンダから油圧ポンプへ向かう作動油の流量を抑えるように制御することにより、フォーク下降速度が急激に増加することを抑制できる。以上により、昇降用の第１油圧シリンダの下降操作と他の第２油圧シリンダの操作が同時に行われる場合に、昇降物を所望の下降速度で下降させることができる。 In the hydraulic drive device for a cargo handling vehicle according to one aspect of the present invention, the second hydraulic fluid passage is connected to the hydraulic fluid from the first hydraulic cylinder via the branch point from the first hydraulic fluid passage for sending hydraulic fluid to the hydraulic pump. Has been. A first flow rate control valve for controlling the flow rate of the hydraulic fluid returning from the first hydraulic cylinder to the tank is disposed on the second hydraulic fluid passage. In the first hydraulic oil flow path, a second flow rate control valve for controlling the flow rate of the hydraulic oil flowing from the first hydraulic cylinder to the hydraulic pump is disposed between the suction port of the hydraulic pump and the branch point. Yes. According to such a configuration, the lowering operation by the first operation unit and the operation of the second operation unit are performed at the same time, so that the motor rotation speed is increased compared with the single operation of the first operation unit, and the flow rate of the hydraulic pump is increased. When it goes up, it can control that a fork lowering speed increases rapidly by controlling so that the 2nd flow control valve may control the flow of hydraulic oil which goes to the hydraulic pump from the 1st hydraulic cylinder. As described above, when the lowering operation of the first hydraulic cylinder for raising and lowering and the operation of the other second hydraulic cylinder are simultaneously performed, the elevator can be lowered at a desired lowering speed.
　また、本発明の他の側面に係る荷役車両の油圧駆動装置において、第２流量制御弁によって制御可能な作動油の流量は、第１流量制御弁によって制御可能な作動油の流量よりも多く設定されていてよい。これにより、所定の下降操作量に対して、第２流量制御弁の制御によって昇降物の下降速度を一定に保つ場合と、第１流量制御弁の制御によって昇降物の下降速度を一定に保った場合とを比較すると、第２流量制御弁の制御による昇降物の下降速度の方を高くすることができる。この場合、モータ回転数が上がることで、第１流量制御弁による制御から第２流量制御弁による制御へ移行する部分に、モータ回転数に伴って昇降物の下降速度が部分的に上がる移行部を設けることができる。このような移行部によって、第１流量制御弁による制御から第２流量制御弁による制御へ急激に変化することを抑制できる。 In the hydraulic drive system for a cargo handling vehicle according to another aspect of the present invention, the flow rate of the hydraulic fluid that can be controlled by the second flow rate control valve is set to be higher than the flow rate of the hydraulic fluid that can be controlled by the first flow rate control valve. May have been. As a result, with respect to a predetermined lowering operation amount, the lowering speed of the lifting / lowering object is kept constant by controlling the second flow rate control valve, and the lowering speed of the lifting / lowering object is kept constant by the control of the first flow rate control valve. In comparison with the case, the descending speed of the lifted object by the control of the second flow rate control valve can be made higher. In this case, when the motor rotational speed is increased, a transition portion in which the descending speed of the ascending / descending object is partially increased with the motor rotational speed at a portion where the control by the first flow control valve is shifted to the control by the second flow control valve. Can be provided. By such a transition part, it can suppress that it changes suddenly from control by the 1st flow control valve to control by the 2nd flow control valve.
　また、本発明の他の側面に係る荷役車両の油圧駆動装置において、第１作動油流路において、第１油圧シリンダと分岐点との間に配設され、第１操作部の下降操作の操作量に応じた開度で開く比例弁と、を更に備え、比例弁の前後の圧力差に基づいて、第２流量制御弁は作動油の流量を制御してよい。これにより、第２流量制御弁は、第１操作部の下降操作の操作量に応じた昇降物の下降速度で制御することができる。 Further, in the hydraulic drive system for a cargo handling vehicle according to another aspect of the present invention, the first hydraulic fluid passage is disposed between the first hydraulic cylinder and the branch point, and is operated to lower the first operation portion. A proportional valve that opens at an opening according to the amount, and the second flow control valve may control the flow rate of the hydraulic oil based on a pressure difference before and after the proportional valve. Thereby, the 2nd flow control valve can be controlled by the descent speed of the raising / lowering object according to the operation amount of the descent operation of the 1st operation part.
　また、本発明の他の側面に係る荷役車両の油圧駆動装置において、第１作動油流路において、第１油圧シリンダと分岐点との間に配設され、第１操作部の下降操作の操作量に応じた開度で開く比例弁と、を更に備え、比例弁の前後の圧力差に基づいて、第１流量制御弁は作動油の流量を制御してよい。これにより、第１流量制御弁は、第１操作部の下降操作の操作量に応じた昇降物の下降速度で制御することができる。 Further, in the hydraulic drive system for a cargo handling vehicle according to another aspect of the present invention, the first hydraulic fluid passage is disposed between the first hydraulic cylinder and the branch point, and is operated to lower the first operation portion. And a proportional valve that opens at an opening according to the amount, and the first flow control valve may control the flow rate of the hydraulic oil based on a pressure difference before and after the proportional valve. Thereby, the 1st flow control valve can be controlled by the descent speed of the raising / lowering object according to the operation amount of the descent operation of the 1st operation part.
　本発明によれば、昇降用油圧シリンダの下降操作と他の油圧シリンダの操作が同時に行われる場合に、昇降物を所望の下降速度で下降させることができる。 According to the present invention, when the lowering operation of the lifting hydraulic cylinder and the operation of other hydraulic cylinders are performed simultaneously, the lifting object can be lowered at a desired lowering speed.
図１は、本発明の実施形態に係る油圧駆動装置を備えた荷役車両を示す側面図である。FIG. 1 is a side view showing a cargo handling vehicle including a hydraulic drive device according to an embodiment of the present invention. 図２は、本発明の実施形態に係る油圧駆動装置を示す油圧回路図である。FIG. 2 is a hydraulic circuit diagram showing the hydraulic drive device according to the embodiment of the present invention. 図３は、図２に示した油圧駆動装置の制御系を示す構成図である。FIG. 3 is a block diagram showing a control system of the hydraulic drive apparatus shown in FIG. 図４は、図２に示した油圧駆動装置の制御系を示すブロック構成図である。4 is a block diagram showing a control system of the hydraulic drive apparatus shown in FIG. 図５は、図３に示したコントローラにより実行される制御処理手順を示すフローチャートである。FIG. 5 is a flowchart showing a control processing procedure executed by the controller shown in FIG. 図６（ａ）は下降操作量とモータ回転数との関係を示すグラフ、図６（ｂ）はモータ回転数とシリンダ流量との関係を示すグラフである。FIG. 6A is a graph showing the relationship between the descending operation amount and the motor rotation speed, and FIG. 6B is a graph showing the relationship between the motor rotation speed and the cylinder flow rate. 図７（ａ）、（ｂ）、（ｃ）は、各制御形態に係るモータ回転数のタイミングチャートを示す図である。FIGS. 7A, 7B, and 7C are diagrams illustrating timing charts of the motor rotation speed according to each control mode. 図８は、各制御形態に係るモータ回転数のタイミングチャートを示す図である。FIG. 8 is a diagram illustrating a timing chart of the motor rotation speed according to each control mode.
　以下、本発明に係る荷役車両の油圧駆動装置の好適な実施形態について、図面を参照して詳細に説明する。なお、図面において、同一または同等の要素には同じ符号を付し、重複する説明を省略する。 Hereinafter, preferred embodiments of a hydraulic drive device for a cargo handling vehicle according to the present invention will be described in detail with reference to the drawings. In the drawings, the same or equivalent elements are denoted by the same reference numerals, and redundant description is omitted.
　図１は、本発明の実施形態に係る油圧駆動装置を備えた荷役車両を示す側面図である。同図において、本実施形態に係る荷役車両１は、バッテリ式のフォークリフトである。荷役車両１は、車体フレーム２と、この車体フレーム２の前部に配置されたマスト３とを備えている。マスト３は、車体フレーム２に傾動可能に支持された左右１対のアウターマスト３ａと、これらのアウターマスト３ａの内側に配置され、アウターマスト３ａに対して昇降可能なインナーマスト３ｂとからなっている。 FIG. 1 is a side view showing a cargo handling vehicle equipped with a hydraulic drive device according to an embodiment of the present invention. In the figure, a cargo handling vehicle 1 according to the present embodiment is a battery-type forklift. The cargo handling vehicle 1 includes a body frame 2 and a mast 3 disposed at a front portion of the body frame 2. The mast 3 includes a pair of left and right outer masts 3a supported to be tiltable on the vehicle body frame 2, and an inner mast 3b which is disposed inside these outer masts 3a and can be moved up and down with respect to the outer mast 3a. Yes.
　マスト３の後側には、昇降用油圧シリンダとしてのリフトシリンダ４が配置されている。リフトシリンダ４のピストンロッド４ｐの先端部は、インナーマスト３ｂの上部に連結されている。 ) A lift cylinder 4 as a lifting hydraulic cylinder is disposed on the rear side of the mast 3. The tip of the piston rod 4p of the lift cylinder 4 is connected to the upper part of the inner mast 3b.
　インナーマスト３ｂには、リフトブラケット５が昇降可能に支持されている。リフトブラケット５には、荷物を積載するフォーク（昇降物）６が取り付けられている。インナーマスト３ｂの上部にはチェーンホイール７が設けられ、チェーンホイール７にはチェーン８が掛装されている。チェーン８の一端部はリフトシリンダ４に連結され、チェーン８の他端部はリフトブラケット５に連結されている。リフトシリンダ４を伸縮させると、チェーン８を介してフォーク６がリフトブラケット５と共に昇降する。 The lift bracket 5 is supported on the inner mast 3b so as to be movable up and down. A fork (lifting object) 6 for loading a load is attached to the lift bracket 5. A chain wheel 7 is provided on the upper portion of the inner mast 3b, and a chain 8 is hooked on the chain wheel 7. One end of the chain 8 is connected to the lift cylinder 4, and the other end of the chain 8 is connected to the lift bracket 5. When the lift cylinder 4 is expanded and contracted, the fork 6 moves up and down with the lift bracket 5 via the chain 8.
　車体フレーム２の左右両側には、傾動用油圧シリンダとしてのティルトシリンダ９がそれぞれ支持されている。ティルトシリンダ９のピストンロッド９ｐの先端部は、アウターマスト３ａの高さ方向ほぼ中央部に回動可能に連結されている。ティルトシリンダ９を伸縮させると、マスト３が傾動する。 A tilt cylinder 9 as a tilting hydraulic cylinder is supported on each of the left and right sides of the body frame 2. The tip of the piston rod 9p of the tilt cylinder 9 is rotatably connected to the substantially central portion of the outer mast 3a in the height direction. When the tilt cylinder 9 is expanded and contracted, the mast 3 tilts.
　車体フレーム２の上部には、運転室１０が設けられている。運転室１０の前部には、リフトシリンダ４を作動させてフォーク６を昇降させるためのリフト操作レバー１１と、ティルトシリンダ９を作動させてマスト３を傾動させるためのティルト操作レバー１２とが設けられている。 A driver's cab 10 is provided on the upper part of the body frame 2. At the front of the cab 10, there are provided a lift operation lever 11 for operating the lift cylinder 4 to raise and lower the fork 6, and a tilt operation lever 12 for operating the tilt cylinder 9 to tilt the mast 3. It has been.
　また、運転室１０の前部には、操舵を行うためのステアリング１３が設けられている。ステアリング１３は、油圧式のパワーステアリングであり、パワーステアリング（ＰＳ）用油圧シリンダとしてのＰＳシリンダ１４（図２参照）により運転者の操舵をアシストすることが可能である。 Further, a steering wheel 13 for steering is provided at the front of the cab 10. The steering 13 is a hydraulic power steering, and can assist the driver's steering by a PS cylinder 14 (see FIG. 2) as a hydraulic cylinder for power steering (PS).
　また、荷役車両１は、アタッチメント（図示せず）を動作させるアタッチメント用油圧シリンダとしてのアタッチメントシリンダ１５（図２参照）を備えている。アタッチメントとしては、例えばフォーク６を左右移動、傾動、回転させるもの等がある。また、運転室１０には、アタッチメントシリンダ１５を作動させてアタッチメントを動作させるためのアタッチメント操作レバー（図示せず）が設けられている。 Further, the cargo handling vehicle 1 includes an attachment cylinder 15 (see FIG. 2) as an attachment hydraulic cylinder for operating an attachment (not shown). As the attachment, for example, there is one that moves, tilts, and rotates the fork 6 left and right. The cab 10 is provided with an attachment operation lever (not shown) for operating the attachment cylinder 15 to operate the attachment.
　さらに、運転室１０には、特に図示はしないが、荷役車両１の走行方向（前進／後進／ニュートラル）を切り換えるためのディレクションスイッチが設けられている。 Furthermore, although not particularly shown, the cab 10 is provided with a direction switch for switching the traveling direction (forward / reverse / neutral) of the cargo handling vehicle 1.
　図２は、本発明に係る油圧駆動装置の第１実施形態を示す油圧回路図である。同図において、本実施形態の油圧駆動装置１６は、リフトシリンダ４、ティルトシリンダ９、アタッチメントシリンダ１５及びＰＳシリンダ１４を駆動する装置である。 FIG. 2 is a hydraulic circuit diagram showing a first embodiment of a hydraulic drive device according to the present invention. In the figure, a hydraulic drive device 16 of the present embodiment is a device that drives a lift cylinder 4, a tilt cylinder 9, an attachment cylinder 15, and a PS cylinder 14.
　油圧駆動装置１６は、単一の油圧ポンプモータ１７と、この油圧ポンプモータ１７を駆動する単一の電動モータ１８とを備えている。油圧ポンプモータ１７は、作動油を吸い込むための吸込口１７ａと、作動油を吐出するための吐出口１７ｂとを有している。油圧ポンプモータ１７は、一方向に回転可能な構成とされている。 The hydraulic drive device 16 includes a single hydraulic pump motor 17 and a single electric motor 18 that drives the hydraulic pump motor 17. The hydraulic pump motor 17 has a suction port 17a for sucking hydraulic oil and a discharge port 17b for discharging hydraulic oil. The hydraulic pump motor 17 is configured to be rotatable in one direction.
　電動モータ１８は、電動機または発電機として機能する。具体的には、油圧ポンプモータ１７が油圧ポンプとして作動する場合には、電動モータ１８は電動機として機能し、油圧ポンプモータ１７が油圧モータとして作動する場合には、電動モータ１８は発電機として機能する。電動モータ１８が発電機として機能すると、電動モータ１８で発生した電力がバッテリ（図示せず）に蓄電される。つまり、回生動作が行われることとなる。 The electric motor 18 functions as an electric motor or a generator. Specifically, when the hydraulic pump motor 17 operates as a hydraulic pump, the electric motor 18 functions as an electric motor, and when the hydraulic pump motor 17 operates as a hydraulic motor, the electric motor 18 functions as a generator. To do. When the electric motor 18 functions as a generator, the electric power generated by the electric motor 18 is stored in a battery (not shown). That is, a regenerative operation is performed.
　油圧ポンプモータ１７の吸込口１７ａには、作動油を貯留するタンク１９が油圧配管２０を介して接続されている。油圧配管２０には、タンク１９から油圧ポンプモータ１７への方向にのみ作動油を流通させる逆止弁２１が設けられている。油圧ポンプモータ１７は、リフト操作レバー１１による上昇操作時にはリフトシリンダ４に作動油を供給するポンプとして機能するとともに、リフト操作レバー１１による下降操作時にはリフトシリンダ４から排出される作動油により駆動される油圧モータとして機能する。 A tank 19 for storing hydraulic oil is connected to the suction port 17a of the hydraulic pump motor 17 via a hydraulic pipe 20. The hydraulic pipe 20 is provided with a check valve 21 for flowing hydraulic oil only in the direction from the tank 19 to the hydraulic pump motor 17. The hydraulic pump motor 17 functions as a pump that supplies hydraulic oil to the lift cylinder 4 when the lift operation lever 11 is raised, and is driven by the hydraulic oil discharged from the lift cylinder 4 when the lift operation lever 11 is lowered. Functions as a hydraulic motor.
　油圧ポンプモータ１７の吐出口１７ｂとリフトシリンダ４のボトム室４ｂとは、油圧配管２２を介して接続されている。油圧配管２２には、リフト上昇用の電磁比例弁２３が配設されている。電磁比例弁２３は、油圧ポンプモータ１７からリフトシリンダ４のボトム室４ｂへの作動油の流通を許容する開位置２３ａと、油圧ポンプモータ１７からリフトシリンダ４のボトム室４ｂへの作動油の流通を遮断する閉位置２３ｂとの間で切り換えられる。 The discharge port 17 b of the hydraulic pump motor 17 and the bottom chamber 4 b of the lift cylinder 4 are connected via a hydraulic pipe 22. The hydraulic piping 22 is provided with an electromagnetic proportional valve 23 for lifting the lift. The electromagnetic proportional valve 23 has an open position 23 a that allows the hydraulic oil to flow from the hydraulic pump motor 17 to the bottom chamber 4 b of the lift cylinder 4, and the hydraulic oil flows from the hydraulic pump motor 17 to the bottom chamber 4 b of the lift cylinder 4. Is switched to the closed position 23b that shuts off.
　電磁比例弁２３は、通常は閉位置２３ｂ（図示）にあり、ソレノイド操作部２３ｃに操作信号（リフト操作レバー１１の上昇操作の操作量に応じたリフト上昇用ソレノイド電流指令値）が入力されると、開位置２３ａに切り換わる。すると、油圧ポンプモータ１７からリフトシリンダ４のボトム室４ｂに作動油が供給され、リフトシリンダ４が伸長し、これに伴ってフォーク６が上昇する。なお、電磁比例弁２３は、開位置２３ａにあるときは、操作信号に応じた開度で開く。油圧配管２２における電磁比例弁２３とリフトシリンダ４との間には、電磁比例弁２３からリフトシリンダ４への方向にのみ作動油を流通させる逆止弁２４が設けられている。 The electromagnetic proportional valve 23 is normally in a closed position 23b (illustrated), and an operation signal (a lift raising solenoid current command value corresponding to an operation amount of the lifting operation of the lift operation lever 11) is input to the solenoid operating portion 23c. Then, it switches to the open position 23a. Then, hydraulic oil is supplied from the hydraulic pump motor 17 to the bottom chamber 4b of the lift cylinder 4, the lift cylinder 4 extends, and the fork 6 rises accordingly. When the electromagnetic proportional valve 23 is in the open position 23a, the electromagnetic proportional valve 23 is opened at an opening corresponding to the operation signal. A check valve 24 is provided between the electromagnetic proportional valve 23 and the lift cylinder 4 in the hydraulic pipe 22 so that hydraulic fluid flows only in the direction from the electromagnetic proportional valve 23 to the lift cylinder 4.
　油圧配管２２における油圧ポンプモータ１７と電磁比例弁２３との分岐点には、油圧配管２５を介してティルト用の電磁比例弁２６が接続されている。油圧配管２５には、油圧ポンプモータ１７から電磁比例弁２６への方向にのみ作動油を流通させる逆止弁２７が設けられている。 A tilting proportional solenoid valve 26 is connected to a branch point between the hydraulic pump motor 17 and the proportional solenoid valve 23 in the hydraulic pipe 22 via a hydraulic pipe 25. The hydraulic pipe 25 is provided with a check valve 27 that allows hydraulic oil to flow only in the direction from the hydraulic pump motor 17 to the electromagnetic proportional valve 26.
　電磁比例弁２６とティルトシリンダ９のロッド室９ａ及びボトム室９ｂとは、油圧配管２８，２９を介してそれぞれ接続されている。電磁比例弁２６は、油圧ポンプモータ１７からティルトシリンダ９のロッド室９ａへの作動油の流通を許容する開位置２６ａと、油圧ポンプモータ１７からティルトシリンダ９のボトム室９ｂへの作動油の流通を許容する開位置２６ｂと、油圧ポンプモータ１７からティルトシリンダ９への作動油の流通を遮断する閉位置２６ｃの間で切り換えられる。 The electromagnetic proportional valve 26 and the rod chamber 9a and the bottom chamber 9b of the tilt cylinder 9 are connected via hydraulic pipes 28 and 29, respectively. The electromagnetic proportional valve 26 has an open position 26 a that allows the hydraulic oil to flow from the hydraulic pump motor 17 to the rod chamber 9 a of the tilt cylinder 9, and the hydraulic oil flows from the hydraulic pump motor 17 to the bottom chamber 9 b of the tilt cylinder 9. Is switched between an open position 26b allowing the hydraulic oil and a closed position 26c interrupting the flow of the hydraulic oil from the hydraulic pump motor 17 to the tilt cylinder 9.
　電磁比例弁２６は、通常は閉位置２６ｃ（図示）にあり、開位置２６ａ側のソレノイド操作部２６ｄに操作信号（ティルト操作レバー１２の後傾操作の操作量に応じたティルト用ソレノイド電流指令値）が入力されると、開位置２６ａに切り換わり、開位置２６ｂ側のソレノイド操作部２６ｅに操作信号（ティルト操作レバー１２の前傾操作の操作量に応じたティルト用ソレノイド電流指令値）が入力されると、開位置２６ｂに切り換わる。電磁比例弁２６が開位置２６ａに切り換わると、油圧ポンプモータ１７からティルトシリンダ９のロッド室９ａに作動油が供給され、ティルトシリンダ９が収縮し、これに伴ってマスト３が後傾する。電磁比例弁２６が開位置２６ｂに切り換わると、油圧ポンプモータ１７からティルトシリンダ９のボトム室９ｂに作動油が供給され、ティルトシリンダ９が伸長し、これに伴ってマスト３が前傾する。なお、電磁比例弁２６は、開位置２６ａ，２６ｂにあるときは、操作信号に応じた開度で開く。 The electromagnetic proportional valve 26 is normally in a closed position 26c (illustrated), and an operation signal (a tilt solenoid current command value corresponding to an operation amount of a tilting operation of the tilt operation lever 12) is sent to a solenoid operation unit 26d on the open position 26a side. ) Is switched to the open position 26a, and an operation signal (tilt solenoid current command value corresponding to the amount of forward tilt operation of the tilt operation lever 12) is input to the solenoid operation portion 26e on the open position 26b side. If it does, it will switch to the open position 26b. When the electromagnetic proportional valve 26 is switched to the open position 26a, hydraulic oil is supplied from the hydraulic pump motor 17 to the rod chamber 9a of the tilt cylinder 9, the tilt cylinder 9 contracts, and the mast 3 tilts backward along with this. When the electromagnetic proportional valve 26 is switched to the open position 26b, hydraulic oil is supplied from the hydraulic pump motor 17 to the bottom chamber 9b of the tilt cylinder 9, the tilt cylinder 9 extends, and the mast 3 tilts forward. When the electromagnetic proportional valve 26 is in the open positions 26a and 26b, the electromagnetic proportional valve 26 is opened at an opening corresponding to the operation signal.
　油圧配管２５における逆止弁２７の上流側には、油圧配管３０を介してアタッチメント用の電磁比例弁３１が接続されている。油圧配管３０には、油圧ポンプモータ１７から電磁比例弁３１への方向にのみ作動油を流通させる逆止弁３２が設けられている。 An electromagnetic proportional valve 31 for attachment is connected to the upstream side of the check valve 27 in the hydraulic pipe 25 via a hydraulic pipe 30. The hydraulic pipe 30 is provided with a check valve 32 that circulates hydraulic oil only in the direction from the hydraulic pump motor 17 to the electromagnetic proportional valve 31.
　電磁比例弁３１とアタッチメントシリンダ１５のロッド室１５ａ及びボトム室１５ｂとは、油圧配管３３，３４を介してそれぞれ接続されている。電磁比例弁３１は、油圧ポンプモータ１７からアタッチメントシリンダ１５のロッド室１５ａへの作動油の流通を許容する開位置３１ａと、油圧ポンプモータ１７からアタッチメントシリンダ１５のボトム室１５ｂへの作動油の流通を許容する開位置３１ｂと、油圧ポンプモータ１７からアタッチメントシリンダ１５への作動油の流通を遮断する閉位置３１ｃの間で切り換えられる。 The electromagnetic proportional valve 31 and the rod chamber 15a and the bottom chamber 15b of the attachment cylinder 15 are connected via hydraulic pipes 33 and 34, respectively. The electromagnetic proportional valve 31 has an open position 31a that allows the hydraulic fluid to flow from the hydraulic pump motor 17 to the rod chamber 15a of the attachment cylinder 15, and the hydraulic fluid to flow from the hydraulic pump motor 17 to the bottom chamber 15b of the attachment cylinder 15. Is switched between an open position 31b that allows the hydraulic oil and a closed position 31c that blocks the flow of hydraulic oil from the hydraulic pump motor 17 to the attachment cylinder 15.
　電磁比例弁３１は、通常は閉位置３１ｃ（図示）にあり、開位置３１ａ側のソレノイド操作部３１ｄに操作信号（アタッチメント操作レバーの一方側操作の操作量に応じたアタッチメント用ソレノイド電流指令値）が入力されると、開位置３１ａに切り換わり、開位置３１ｂ側のソレノイド操作部３１ｅに操作信号（アタッチメント操作レバーの他方側操作の操作量に応じたアタッチメント用ソレノイド電流指令値）が入力されると、開位置３１ｂに切り換わる。なお、アタッチメントシリンダ１５の動作については省略する。また、電磁比例弁３１は、開位置３１ａ，３１ｂにあるときは、操作信号に応じた開度で開く。 The electromagnetic proportional valve 31 is normally in a closed position 31c (illustrated), and an operation signal (attachment solenoid current command value corresponding to an operation amount of one side operation of the attachment operation lever) is sent to a solenoid operation unit 31d on the open position 31a side. Is switched to the open position 31a, and an operation signal (attachment solenoid current command value corresponding to the operation amount of the other operation of the attachment operation lever) is input to the solenoid operation portion 31e on the open position 31b side. And switch to the open position 31b. The operation of the attachment cylinder 15 is omitted. Further, when the electromagnetic proportional valve 31 is in the open positions 31a and 31b, the electromagnetic proportional valve 31 is opened at an opening corresponding to the operation signal.
　油圧配管３０における逆止弁３２の上流側には、油圧配管３５を介してＰＳ用の電磁比例弁３６が接続されている。油圧配管３５には、油圧ポンプモータ１７から電磁比例弁３６への方向にのみ作動油を流通させる逆止弁３７が設けられている。 PS An electromagnetic proportional valve 36 for PS is connected to the upstream side of the check valve 32 in the hydraulic pipe 30 via a hydraulic pipe 35. The hydraulic pipe 35 is provided with a check valve 37 for flowing hydraulic oil only in the direction from the hydraulic pump motor 17 to the electromagnetic proportional valve 36.
　電磁比例弁３６とＰＳシリンダ１４の第１ロッド室１４ａ及び第２ロッド室１４ｂとは、油圧配管３８，３９を介してそれぞれ接続されている。電磁比例弁３６は、油圧ポンプモータ１７からＰＳシリンダ１４の第１ロッド室１４ａへの作動油の流通を許容する開位置３６ａと、油圧ポンプモータ１７からＰＳシリンダ１４の第２ロッド室１４ｂへの作動油の流通を許容する開位置３６ｂと、油圧ポンプモータ１７からＰＳシリンダ１４への作動油の流通を遮断する閉位置３６ｃの間で切り換えられる。 The electromagnetic proportional valve 36 and the first rod chamber 14a and the second rod chamber 14b of the PS cylinder 14 are connected via hydraulic pipes 38 and 39, respectively. The electromagnetic proportional valve 36 has an open position 36a that allows the hydraulic oil to flow from the hydraulic pump motor 17 to the first rod chamber 14a of the PS cylinder 14, and from the hydraulic pump motor 17 to the second rod chamber 14b of the PS cylinder 14. The position is switched between an open position 36 b that allows the hydraulic oil to flow and a closed position 36 c that blocks the hydraulic oil flow from the hydraulic pump motor 17 to the PS cylinder 14.
　電磁比例弁３６は、通常は閉位置３６ｃ（図示）にあり、開位置３６ａ側のソレノイド操作部３６ｄに操作信号（ステアリング１３の左右一方側操作の操作速度に応じたＰＳ用ソレノイド電流指令値）が入力されると、開位置３６ａに切り換わり、開位置３６ｂ側のソレノイド操作部３６ｅに操作信号（ステアリング１３の左右他方側操作の操作速度に応じたＰＳ用ソレノイド電流指令値）が入力されると、開位置３６ｂに切り換わる。なお、ＰＳシリンダ１４の動作については省略する。また、電磁比例弁３６は、開位置３６ａ，３６ｂにあるときは、操作信号に応じた開度で開く。 The electromagnetic proportional valve 36 is normally in a closed position 36c (illustrated), and an operation signal (PS solenoid current command value corresponding to the operation speed of the left and right one side operation of the steering wheel 13) is sent to the solenoid operation unit 36d on the open position 36a side. Is switched to the open position 36a, and an operation signal (PS solenoid current command value corresponding to the operation speed of the left and right other side operation of the steering wheel 13) is input to the solenoid operating portion 36e on the open position 36b side. Then, it switches to the open position 36b. Note that the operation of the PS cylinder 14 is omitted. When the electromagnetic proportional valve 36 is in the open positions 36a and 36b, the electromagnetic proportional valve 36 is opened at an opening corresponding to the operation signal.
　油圧配管２２における油圧ポンプモータ１７と電磁比例弁２３との分岐点は、油圧配管４０を介してタンク１９と接続されている。油圧配管４０には、アンロード弁４１及びフィルタ４２が設けられている。また、油圧配管４０と電磁比例弁２６，３１，３６とは、油圧配管４３～４５を介して接続されている。さらに、電磁比例弁２３，２６，３１，３６は、油圧配管４６を介して油圧配管４０と接続されている。 The branch point between the hydraulic pump motor 17 and the electromagnetic proportional valve 23 in the hydraulic pipe 22 is connected to the tank 19 via the hydraulic pipe 40. The hydraulic pipe 40 is provided with an unload valve 41 and a filter 42. The hydraulic piping 40 and the electromagnetic proportional valves 26, 31, 36 are connected via hydraulic piping 43-45. Further, the electromagnetic proportional valves 23, 26, 31, 36 are connected to the hydraulic pipe 40 via the hydraulic pipe 46.
　油圧ポンプモータ１７の吸込口１７ａとリフトシリンダ４のボトム室４ｂとは、油圧配管（第１作動油流路）４７を介して接続されている。油圧配管４７は、リフト操作レバー１１による単独下降操作時にはリフトシリンダ４から排出される作動油が油圧ポンプモータ１７の吸込口１７ａへと流れるように、リフトシリンダ４のボトム室４ｂと油圧ポンプモータ１７の吸込口１７ａとを接続する。油圧配管４７には、フォーク下降用の電磁比例弁４８が配設されている。電磁比例弁４８は、リフトシリンダ４のボトム室４ｂから油圧ポンプモータ１７の吸込口１７ａへの作動油の流通を許容する開位置４８ａと、リフトシリンダ４のボトム室４ｂから油圧ポンプモータ１７の吸込口１７ａへの作動油の流通を遮断する閉位置４８ｂとの間で切り換えられる。 The suction port 17 a of the hydraulic pump motor 17 and the bottom chamber 4 b of the lift cylinder 4 are connected via a hydraulic pipe (first hydraulic fluid passage) 47. The hydraulic piping 47 is connected to the bottom chamber 4b of the lift cylinder 4 and the hydraulic pump motor 17 so that the hydraulic oil discharged from the lift cylinder 4 flows to the suction port 17a of the hydraulic pump motor 17 when the lift operation lever 11 is operated alone. To the suction port 17a. The hydraulic pipe 47 is provided with an electromagnetic proportional valve 48 for lowering the fork. The electromagnetic proportional valve 48 includes an open position 48 a that allows the hydraulic oil to flow from the bottom chamber 4 b of the lift cylinder 4 to the suction port 17 a of the hydraulic pump motor 17, and the suction of the hydraulic pump motor 17 from the bottom chamber 4 b of the lift cylinder 4. It is switched between a closed position 48b that blocks the flow of hydraulic oil to the port 17a.
　電磁比例弁４８は、通常は閉位置４８ｂ（図示）にあり、ソレノイド操作部４８ｃに操作信号（リフト操作レバー１１の下降操作の操作量に応じたフォーク下降用ソレノイド電流指令値）が入力されると、開位置４８ａに切り換わる。すると、フォーク６の自重によりフォーク６が下降し、これに伴ってリフトシリンダ４が収縮し、リフトシリンダ４のボトム室４ｂから作動油が流れ出る。なお、電磁比例弁４８は、開位置４８ａにあるときは、操作信号に応じた開度で開く。 The electromagnetic proportional valve 48 is normally in a closed position 48b (illustrated), and an operation signal (a solenoid current command value for fork lowering according to an operation amount of the lowering operation of the lift operation lever 11) is input to the solenoid operating portion 48c. Then, it switches to the open position 48a. Then, the fork 6 descends due to the weight of the fork 6, and the lift cylinder 4 contracts accordingly, and hydraulic oil flows out from the bottom chamber 4 b of the lift cylinder 4. When the electromagnetic proportional valve 48 is in the open position 48a, the electromagnetic proportional valve 48 is opened at an opening corresponding to the operation signal.
　油圧配管４７における油圧ポンプモータ１７と電磁比例弁４８との分岐点９１は、油圧配管（第２作動油流路）４９を介してタンク１９と接続されている。油圧配管４９には、バイパス用流量制御弁（第１流量制御弁）５０が配設されている。バイパス用流量制御弁５０は、リフトシリンダ４からタンク１９に戻る作動油の流量を制御する。なお、油圧配管４９には、フィルタ５４が設けられている。 A branch point 91 between the hydraulic pump motor 17 and the electromagnetic proportional valve 48 in the hydraulic pipe 47 is connected to the tank 19 via a hydraulic pipe (second hydraulic oil flow path) 49. The hydraulic pipe 49 is provided with a bypass flow control valve (first flow control valve) 50. The bypass flow control valve 50 controls the flow rate of the hydraulic oil that returns from the lift cylinder 4 to the tank 19. The hydraulic pipe 49 is provided with a filter 54.
　バイパス用流量制御弁５０は、作動油の流通を許容する開位置５０ａと、作動油の流通を遮断する閉位置５０ｂと、作動油の流通量を調整する絞り位置５０ｃとの間で切り換えられる。バイパス用流量制御弁５０の閉位置５０ｂ側のパイロット操作部と電磁比例弁４８の上流側（前側）とは、パイロット流路５１を介して接続されている。バイパス用流量制御弁５０の開位置５０ａ側のパイロット操作部と電磁比例弁４８の下流側（後側）とは、パイロット流路５２を介して接続されている。バイパス用流量制御弁５０は、電磁比例弁４８の前後の圧力差に応じた開度で開く。具体的には、バイパス用流量制御弁５０は、電磁比例弁４８が閉じている通常時には閉位置にある。そして、電磁比例弁４８が開状態となるとバイパス用流量制御弁５０は電磁比例弁４８の前後の圧力差に応じた開度で開く。この時、電磁比例弁４８の前後の圧力差が小さくなるほど、バイパス用流量制御弁５０の開度は大きくなり、電磁比例弁４８の前後の圧力差が大きくなるほど、バイパス用流量制御弁５０の開度は小さくなる。 The bypass flow control valve 50 is switched between an open position 50a that allows the flow of hydraulic fluid, a closed position 50b that blocks the flow of hydraulic fluid, and a throttle position 50c that adjusts the flow rate of hydraulic fluid. The pilot operating part on the closed position 50 b side of the bypass flow control valve 50 and the upstream side (front side) of the electromagnetic proportional valve 48 are connected via a pilot flow path 51. The pilot operating part on the open position 50 a side of the bypass flow control valve 50 and the downstream side (rear side) of the electromagnetic proportional valve 48 are connected via a pilot flow path 52. The bypass flow control valve 50 opens at an opening corresponding to the pressure difference before and after the electromagnetic proportional valve 48. Specifically, the bypass flow control valve 50 is in the closed position at the normal time when the electromagnetic proportional valve 48 is closed. When the electromagnetic proportional valve 48 is opened, the bypass flow control valve 50 opens at an opening degree corresponding to the pressure difference before and after the electromagnetic proportional valve 48. At this time, as the pressure difference before and after the electromagnetic proportional valve 48 becomes smaller, the opening degree of the bypass flow control valve 50 becomes larger. As the pressure difference before and after the electromagnetic proportional valve 48 becomes larger, the bypass flow control valve 50 opens. The degree becomes smaller.
　油圧配管４７において、油圧ポンプモータ１７の吸込口１７ａと分岐点９１との間には、回生用流量制御弁（第２流量制御弁）８０が配設される。回生用流量制御弁８０は、リフトシリンダ４から油圧ポンプモータ１７へ流れる作動油の流量を制御する。回生用流量制御弁８０は、作動油の流通を許容する開位置８０ａと、作動油の流通を遮断する閉位置８０ｂと、作動油の流通量を調整する絞り位置８０ｃとの間で切り換えられる。回生用流量制御弁８０の閉位置８０ｂ側のパイロット操作部と電磁比例弁４８の上流側（前側）とは、パイロット流路８１を介して接続されている。回生用流量制御弁８０の開位置８０ａ側のパイロット操作部と電磁比例弁４８の下流側（後側）とは、パイロット流路８２を介して接続されている。回生用流量制御弁８０は、電磁比例弁４８の前後の圧力差に応じた開度で開く。具体的には、回生用流量制御弁８０は、電磁比例弁４８が閉じている通常時には閉位置にある。そして、電磁比例弁４８が開状態となると、回生用流量制御弁８０は電磁比例弁４８の前後の圧力差に応じた開度で開く。この時、電磁比例弁４８の前後の圧力差が小さくなるほど、回生用流量制御弁８０の開度は大きくなり、電磁比例弁４８の前後の圧力差が大きくなるほど、回生用流量制御弁８０の開度は小さくなる。 In the hydraulic pipe 47, a regenerative flow control valve (second flow control valve) 80 is disposed between the suction port 17a of the hydraulic pump motor 17 and the branch point 91. The regenerative flow control valve 80 controls the flow rate of the hydraulic fluid flowing from the lift cylinder 4 to the hydraulic pump motor 17. The regenerative flow control valve 80 is switched between an open position 80a that allows the flow of hydraulic fluid, a closed position 80b that blocks the flow of hydraulic fluid, and a throttle position 80c that adjusts the flow rate of hydraulic fluid. The pilot operating portion on the closed position 80 b side of the regenerative flow control valve 80 and the upstream side (front side) of the electromagnetic proportional valve 48 are connected via a pilot flow path 81. The pilot operating portion on the open position 80 a side of the regenerative flow control valve 80 and the downstream side (rear side) of the electromagnetic proportional valve 48 are connected via a pilot flow path 82. The regenerative flow control valve 80 opens at an opening corresponding to the pressure difference before and after the electromagnetic proportional valve 48. Specifically, the regenerative flow control valve 80 is in the closed position at the normal time when the electromagnetic proportional valve 48 is closed. When the electromagnetic proportional valve 48 is opened, the regenerative flow control valve 80 is opened at an opening corresponding to the pressure difference before and after the electromagnetic proportional valve 48. At this time, as the pressure difference before and after the electromagnetic proportional valve 48 decreases, the opening degree of the regenerative flow control valve 80 increases, and as the pressure difference before and after the electromagnetic proportional valve 48 increases, the regenerative flow control valve 80 opens. The degree becomes smaller.
　上述で説明したシリンダのうち、作動油の給排によりリフトシリンダ（第１油圧シリンダ）４と異なる動作を行うティルトシリンダ９、アタッチメントシリンダ１５、及びＰＳシリンダ１４を総称して「第２油圧シリンダ７０」と称することがある。また、第２油圧シリンダ７０を操作するためのレバーである、ティルト操作レバー１２、ステアリング１３、アタッチメント操作レバーを総称して「第２操作部７３」と称することがある。 Among the cylinders described above, the tilt cylinder 9, the attachment cylinder 15, and the PS cylinder 14 that perform different operations from the lift cylinder (first hydraulic cylinder) 4 by supplying and discharging hydraulic oil are collectively referred to as “second hydraulic cylinder 70. May be called. Further, the tilt operation lever 12, the steering wheel 13, and the attachment operation lever, which are levers for operating the second hydraulic cylinder 70, may be collectively referred to as a “second operation unit 73”.
　図３は、油圧駆動装置１６の制御系を示す構成図である。同図において、油圧駆動装置１６は、リフト操作レバー１１の操作量を検出するリフト操作レバー操作量センサ（操作量検出部）５５と、ティルト操作レバー１２の操作量を検出するティルト操作レバー操作量センサ５６と、アタッチメント操作レバー（図示せず）の操作量を検出するアタッチメント操作レバー操作量センサ５７と、ステアリング１３の操作速度を検出するステアリング操作速度センサ５８と、電動モータ１８の実回転数（モータ実回転数）を検出する回転数センサ５９と、コントローラ６０と、を備えている。 FIG. 3 is a configuration diagram showing a control system of the hydraulic drive device 16. In the figure, a hydraulic drive device 16 includes a lift operation lever operation amount sensor (operation amount detection unit) 55 that detects an operation amount of the lift operation lever 11 and a tilt operation lever operation amount that detects an operation amount of the tilt operation lever 12. A sensor 56, an attachment operation lever operation amount sensor 57 for detecting the operation amount of an attachment operation lever (not shown), a steering operation speed sensor 58 for detecting the operation speed of the steering wheel 13, and the actual rotational speed of the electric motor 18 ( A rotation speed sensor 59 for detecting the actual rotation speed of the motor) and a controller 60 are provided.
　コントローラ６０は、操作レバー操作量センサ５５～５７、ステアリング操作速度センサ５８、回転数センサ５９の検出値を入力し、所定の処理を行い、電動モータ１８、電磁比例弁２３，２６，３１，３６，４８を制御する。なお、第２操作部７３の操作量を検出するセンサ５６，５７，５８を「第２操作量検出部７１」と称することがある。また、油圧ポンプモータ１７の吐出口１７ｂと第２油圧シリンダとの間に配設され、第２操作部７３の操作に基づいて前記作動油の流れを制御する電磁比例弁２６，３１，３６を「第２制御弁７２」と称することがある。 The controller 60 inputs detection values of the operation lever operation amount sensors 55 to 57, the steering operation speed sensor 58, and the rotation speed sensor 59, performs a predetermined process, and performs the electric motor 18, the electromagnetic proportional valves 23, 26, 31, 36. , 48 are controlled. The sensors 56, 57, and 58 that detect the operation amount of the second operation unit 73 may be referred to as “second operation amount detection unit 71”. In addition, electromagnetic proportional valves 26, 31, 36 that are disposed between the discharge port 17 b of the hydraulic pump motor 17 and the second hydraulic cylinder and control the flow of the hydraulic oil based on the operation of the second operation unit 73 are provided. It may be referred to as “second control valve 72”.
　図４は、油圧駆動装置１６の制御系のブロック構成を示すブロック構成図である。図４に示すように、コントローラ６０は、モータドライバ６１と、力行トルク制限制御目標回転数算出部６６と、モータ指令回転数算出部６７と、判定部６９と、を備える。 FIG. 4 is a block configuration diagram showing a block configuration of a control system of the hydraulic drive device 16. As shown in FIG. 4, the controller 60 includes a motor driver 61, a power running torque limit control target rotational speed calculation unit 66, a motor command rotational speed calculation unit 67, and a determination unit 69.
　モータドライバ６１は、比較部６２Ａ，６２Ｂと、ＰＩＤ演算部６３と、力行トルク制限値算出部６８と、出力トルク決定部（制御部）６４と、モータ制御部（制御部）６５とを有している。比較部６２Ａは、モータ指令回転数算出部６７で設定されたモータ指令回転数と回転数センサ５９により検出されたモータ実回転数との回転数偏差を算出する。比較部６２Ｂは、力行トルク制限制御目標回転数算出部６６で設定された力行トルク制限制御目標回転数と回転数センサ５９により検出されたモータ実回転数との回転数偏差を算出する。ＰＩＤ演算部６３は、モータ指令回転数とモータ実回転数との回転数偏差のＰＩＤ演算を行い、当該回転数偏差がゼロになるような電動モータ１８の力行トルク指令値を求める。ＰＩＤ演算は、比例（Proportional）動作、積分（Integral）動作及び微分（Derivative）動作を組み合わせた演算である。力行トルク制限値算出部６８は、力行トルク制限制御目標回転数と回転数センサ５９により検出されたモータ実回転数との回転数偏差に基づいて、電動モータ１８の力行トルク制限値を算出し、設定する。力行トルク制限値とは、電動モータ１８の出力トルクが力行側へ向かう場合に、出力トルクが大きくならないように制限するための値である。なお、力行トルク制限値算出部６８が設定する力行トルク制限値については詳述する。 The motor driver 61 includes comparison units 62A and 62B, a PID calculation unit 63, a power running torque limit value calculation unit 68, an output torque determination unit (control unit) 64, and a motor control unit (control unit) 65. ing. The comparison unit 62A calculates a rotational speed deviation between the motor command rotational speed set by the motor command rotational speed calculation unit 67 and the actual motor rotational speed detected by the rotational speed sensor 59. The comparison unit 62B calculates a rotational speed deviation between the power running torque limit control target rotational speed set by the power running torque limit control target rotational speed calculation unit 66 and the actual motor rotational speed detected by the rotational speed sensor 59. The PID calculation unit 63 performs a PID calculation of a rotation speed deviation between the motor command rotation speed and the motor actual rotation speed, and obtains a power running torque command value of the electric motor 18 such that the rotation speed deviation becomes zero. The PID calculation is a combination of a proportional operation, an integral operation, and a derivative operation. The power running torque limit value calculation unit 68 calculates the power running torque limit value of the electric motor 18 based on the rotation speed deviation between the power running torque limit control target rotation speed and the actual motor rotation speed detected by the rotation speed sensor 59. Set. The power running torque limit value is a value for limiting the output torque so as not to increase when the output torque of the electric motor 18 moves toward the power running side. The power running torque limit value set by the power running torque limit value calculation unit 68 will be described in detail.
　制御部を構成する出力トルク決定部６４及びモータ制御部６５は、モータ指令回転数（回転数指令値）に基づく回転数となるように電動モータ１８を制御し、電動モータ１８の出力トルクが力行側へ向かう場合は、力行トルク制限値に基づく回転数となるように電動モータ１８を制御する。出力トルク決定部６４は、ＰＩＤ演算部６３で得られた力行トルク指令値（モータ指令回転数に基づいている値である）と力行トルク制限値算出部６８で設定された電動モータ１８の力行トルク制限値とを比較し、電動モータ１８の出力トルクを決定する。具体的には、力行トルク指令値が力行トルク制限値以下のときは、力行トルク指令値を電動モータ１８の出力トルクとし、力行トルク指令値が力行トルク制限値よりも高いときは、力行トルク制限値を電動モータ１８の出力トルクとする。モータ制御部６５は、出力トルク決定部６４で決定された出力トルクを電流信号に変換して電動モータ１８に送出する。なお、電動モータ１８が、力行トルク制限値に基づく回転数となるように制御されることにより、モータ指令回転数に基づく駆動を達成できない場合、バイパス用流量制御弁５０は、油圧配管４９を介してタンク１９へ作動油を排出する。 The output torque determination unit 64 and the motor control unit 65 constituting the control unit control the electric motor 18 so that the rotation speed is based on the motor command rotation speed (rotation speed command value), and the output torque of the electric motor 18 is power running. When heading to the side, the electric motor 18 is controlled so that the rotational speed is based on the power running torque limit value. The output torque determination unit 64 is a power running torque command value (a value based on the motor command rotational speed) obtained by the PID calculation unit 63 and a power running torque of the electric motor 18 set by the power running torque limit value calculation unit 68. The output torque of the electric motor 18 is determined by comparing with the limit value. Specifically, when the power running torque command value is less than or equal to the power running torque limit value, the power running torque command value is set as the output torque of the electric motor 18, and when the power running torque command value is higher than the power running torque limit value, the power running torque limit is set. The value is the output torque of the electric motor 18. The motor control unit 65 converts the output torque determined by the output torque determination unit 64 into a current signal and sends it to the electric motor 18. When the electric motor 18 is controlled so as to have a rotational speed based on the power running torque limit value and cannot be driven based on the motor command rotational speed, the bypass flow control valve 50 is connected via the hydraulic pipe 49. The hydraulic oil is discharged to the tank 19.
　モータ指令回転数算出部６７は、各センサ５５，５６，５７，５８で検出された検出値を取得し、当該検出値に基づいてモータ指令回転数（回転数指令値）を設定する。モータ指令回転数算出部６７は、各操作レバーの操作量に応じてモータ指令回転数を設定する。なお、モータ指令回転数算出部６７が設定するモータ指令回転数については詳述する。力行トルク制限制御目標回転数算出部６６は、各センサ５５，５６，５７，５８で検出された検出値を取得し、当該検出値に基づいて力行トルク制限制御目標回転数を設定する。力行トルク制限制御目標回転数算出部６６は、各操作レバーの操作状況に応じて力行トルク制限制御目標回転数を設定する。 The motor command rotation speed calculation unit 67 acquires detection values detected by the sensors 55, 56, 57, and 58, and sets a motor command rotation speed (rotation speed command value) based on the detection values. The motor command rotation speed calculation unit 67 sets the motor command rotation speed according to the operation amount of each operation lever. The motor command rotational speed set by the motor command rotational speed calculation unit 67 will be described in detail. The power running torque limit control target rotational speed calculation unit 66 acquires the detection values detected by the sensors 55, 56, 57, and 58, and sets the power running torque limit control target rotational speed based on the detected values. The power running torque limit control target rotational speed calculation unit 66 sets the power running torque limit control target rotational speed according to the operation state of each operation lever.
　判定部６９は、リフト操作レバー１１の下降操作が単独で行われたか否かと、リフト操作レバー１１の下降操作を含む第２操作部７３の操作が同時に行われたか否かを判定する。例えば、フォーク下降＋ティルト操作、フォーク下降＋アタッチメント操作、フォーク下降＋パワーステアリング操作、フォーク下降＋ティルト＋パワーステアリング操作が行われた場合、判定部６９は、リフト操作レバー１１を含む第２操作部７３の操作が同時に行われたと判定する。判定部６９は、判定結果をモータ指令回転数算出部６７及び力行トルク制限値算出部６８に判定結果を出力する。 The determination unit 69 determines whether the lowering operation of the lift operation lever 11 is performed alone and whether the operation of the second operation unit 73 including the lowering operation of the lift operation lever 11 is performed simultaneously. For example, when the fork lowering + tilt operation, the fork lowering + attachment operation, the fork lowering + power steering operation, and the fork lowering + tilt + power steering operation are performed, the determination unit 69 includes the second operation unit including the lift operation lever 11. It is determined that the operations 73 are performed simultaneously. The determination unit 69 outputs the determination result to the motor command rotational speed calculation unit 67 and the power running torque limit value calculation unit 68.
　図５は、コントローラ６０により実行される制御処理手順を示すフローチャートである。なお、本制御処理では、フォーク６の下降（フォーク下降）を含む動作のみを対象としている。また、本制御処理を実行する周期は、実験等により適宜決められている。 FIG. 5 is a flowchart showing a control processing procedure executed by the controller 60. In this control process, only the operation including the lowering of the fork 6 (fork lowering) is targeted. In addition, the period for executing this control process is appropriately determined by experiments or the like.
　同図において、まず操作レバー操作量センサ５５～５７により検出されたリフト操作レバー１１、ティルト操作レバー１２及びアタッチメント操作レバーの操作量と、ステアリング操作速度センサ５８により検出されたステアリング１３の操作速度とを取得する（手順Ｓ１０１）。 In the figure, first, the operation amounts of the lift operation lever 11, the tilt operation lever 12 and the attachment operation lever detected by the operation lever operation amount sensors 55 to 57, and the operation speed of the steering wheel 13 detected by the steering operation speed sensor 58 are shown. Is acquired (procedure S101).
　続いて、手順Ｓ１０１で取得されたリフト操作レバー１１、ティルト操作レバー１２、アタッチメント操作レバーの操作量及びステアリング１３の操作速度に基づいて、操作条件としてのフォーク下降モードを判定する（手順Ｓ１０２）。フォーク下降モードとしては、フォーク下降単独操作、フォーク下降＋ティルト操作、フォーク下降＋アタッチメント操作、フォーク下降＋パワーステアリング操作、フォーク下降＋ティルト＋パワーステアリング操作がある。 Subsequently, the fork lowering mode as the operation condition is determined based on the operation amount of the lift operation lever 11, the tilt operation lever 12, the attachment operation lever and the operation speed of the steering wheel 13 acquired in step S101 (step S102). Fork lowering modes include fork lowering single operation, fork lowering + tilt operation, fork lowering + attachment operation, fork lowering + power steering operation, fork lowering + tilt + power steering operation.
　続いて、手順Ｓ１０１で取得されたリフト操作レバー１１、ティルト操作レバー１２、アタッチメント操作レバーの操作量及びステアリング１３の操作速度と手順Ｓ１０２で判定されたフォーク下降モードとに応じた電磁比例弁ソレノイド電流指令値を求める（手順Ｓ１０３）。電磁比例弁ソレノイド電流指令値としては、リフト操作レバー１１の下降操作の操作量に応じたフォーク下降用ソレノイド電流指令値、ティルト操作レバー１２の操作量に応じたティルト用ソレノイド電流指令値、アタッチメント操作レバーの操作量に応じたアタッチメント用ソレノイド電流指令値、ステアリング１３の操作速度に応じたパワーステアリング（ＰＳ）用ソレノイド電流指令値がある。 Subsequently, the solenoid proportional valve solenoid current according to the operation amount of the lift operation lever 11, the tilt operation lever 12, the attachment operation lever and the operation speed of the steering wheel 13 acquired in step S101 and the fork lowering mode determined in step S102. A command value is obtained (procedure S103). The solenoid proportional valve solenoid current command value includes a fork lowering solenoid current command value corresponding to the operation amount of the lowering operation of the lift operation lever 11, a tilt solenoid current command value corresponding to the operation amount of the tilt operation lever 12, and an attachment operation. There are an attachment solenoid current command value according to the lever operation amount and a power steering (PS) solenoid current command value according to the operation speed of the steering 13.
　続いて、手順Ｓ１０２で得られた操作条件に対する必要回転数を求める（手順Ｓ１０４）。必要回転数としては、リフト必要モータ回転数、ティルト必要モータ回転数、アタッチメント必要モータ回転数及びパワーステアリング（ＰＳ）必要モータ回転数がある。リフト必要モータ回転数は、リフト動作を行うのに必要な電動モータ１８の回転数である。ティルト必要モータ回転数は、ティルト動作を行うのに必要な電動モータ１８の回転数である。アタッチメント必要モータ回転数は、アタッチメント動作を行うのに必要な電動モータ１８の回転数である。ＰＳ必要モータ回転数は、ＰＳ動作を行うのに必要な電動モータ１８の回転数である。 Subsequently, the necessary rotational speed for the operation condition obtained in step S102 is obtained (step S104). The required rotational speed includes a lift required motor speed, a tilt required motor speed, an attachment required motor speed, and a power steering (PS) required motor speed. The lift required motor rotation speed is the rotation speed of the electric motor 18 necessary for performing the lift operation. The tilt required motor rotational speed is the rotational speed of the electric motor 18 necessary for performing the tilt operation. The attachment-required motor rotational speed is the rotational speed of the electric motor 18 necessary for performing the attachment operation. The PS required motor rotational speed is the rotational speed of the electric motor 18 necessary for performing the PS operation.
　続いて、モータ指令回転数算出部６７は、手順Ｓ１０２で判定されたフォーク下降モードと手順Ｓ１０４で得られた必要回転数に基づいて、モータ回転数指令値（モータ指令回転数）を設定する（手順Ｓ１０５）。このとき、モータ指令回転数は、上述の図６に基づいて設定される。 Subsequently, the motor command rotational speed calculation unit 67 sets a motor rotational speed command value (motor command rotational speed) based on the fork lowering mode determined in step S102 and the necessary rotational speed obtained in step S104 ( Procedure S105). At this time, the motor command rotational speed is set based on the above-described FIG.
　続いて、手順Ｓ１０２で判定されたフォーク下降モードに基づいて、電動モータ１８の力行トルク制限値を設定する（手順Ｓ１０６）。力行トルク制限値は、許容する力行トルクの値のことである。このとき、力行トルク制限値算出部６８は、上述の図６に基づいて設定される。 Subsequently, the power running torque limit value of the electric motor 18 is set based on the fork lowering mode determined in step S102 (step S106). The power running torque limit value is an allowable power running torque value. At this time, the power running torque limit value calculation unit 68 is set based on the above-described FIG.
　手順Ｓ１０６を実施した後、手順Ｓ１０３で得られた電磁比例弁ソレノイド電流指令値を対応する電磁比例弁のソレノイド操作部に送出する（手順Ｓ１０７）。このとき、フォーク下降用ソレノイド電流指令値を電磁比例弁４８のソレノイド操作部４８ｃに送出する。また、ティルト用ソレノイド電流指令値を求めたときは、その電流指令値を電磁比例弁２６のソレノイド操作部２６ｄ，２６ｅの何れかに送出し、アタッチメント用ソレノイド電流指令値を求めたときは、その電流指令値を電磁比例弁３１のソレノイド操作部３１ｄ，３１ｅの何れかに送出し、ＰＳ用ソレノイド電流指令値を求めたときは、その電流指令値を電磁比例弁３６のソレノイド操作部３６ｄ，３６ｅの何れかに送出する。 After executing step S106, the electromagnetic proportional valve solenoid current command value obtained in step S103 is sent to the solenoid operation unit of the corresponding electromagnetic proportional valve (step S107). At this time, the fork lowering solenoid current command value is sent to the solenoid operating portion 48 c of the electromagnetic proportional valve 48. Also, when the tilt solenoid current command value is obtained, the current command value is sent to either of the solenoid operating portions 26d and 26e of the electromagnetic proportional valve 26, and when the attachment solenoid current command value is obtained, When the current command value is sent to one of the solenoid operating portions 31d and 31e of the electromagnetic proportional valve 31 and the PS solenoid current command value is obtained, the current command value is sent to the solenoid operating portions 36d and 36e of the electromagnetic proportional valve 36. To any of the above.
　続いて、手順Ｓ１０５で設定されたモータ回転数指令値（モータ指令回転数）と回転数センサ５９により検出されたモータ実回転数と手順Ｓ１０６で設定された電動モータ１８の力行トルク制限値とに基づいて電動モータ１８の出力トルクを求め、その出力トルクを制御信号として電動モータ１８に送出する（手順Ｓ１０８）。手順Ｓ１０８の処理は、図４に示すように、コントローラ６０に含まれるモータドライバ６１により実行される。 Subsequently, the motor rotational speed command value (motor command rotational speed) set in step S105, the actual motor rotational speed detected by the rotational speed sensor 59, and the power running torque limit value of the electric motor 18 set in step S106 are obtained. Based on this, the output torque of the electric motor 18 is obtained, and the output torque is sent to the electric motor 18 as a control signal (step S108). The process of step S108 is executed by a motor driver 61 included in the controller 60 as shown in FIG.
　次に、図６を参照して、本実施形態の油圧駆動装置１６における電動モータ１８のモータ回転数とリフトシリンダ４のシリンダ流量の特性について説明する。図６（ａ）は、下降操作量とモータ回転数との関係を示すグラフである。図６（ａ）の横軸は、リフト操作レバー１１の操作量（以下、下降操作量と称する）であり、縦軸は、電動モータ１８のモータ回転数を示している。なお、モータ回転数は、油圧ポンプモータ１７のポンプ回転数と同等であり、下降用の電磁比例弁４８の開度に対応する値である。図６（ａ）に示すように、下降操作量とモータ回転数（すなわち下降用の電磁比例弁４８の開度）との間には正比例の関係が成り立つ。 Next, the characteristics of the motor rotation speed of the electric motor 18 and the cylinder flow rate of the lift cylinder 4 in the hydraulic drive device 16 of the present embodiment will be described with reference to FIG. FIG. 6A is a graph showing the relationship between the lowering operation amount and the motor rotation speed. The horizontal axis of FIG. 6A is the operation amount of the lift operation lever 11 (hereinafter referred to as the downward operation amount), and the vertical axis indicates the motor rotation speed of the electric motor 18. The motor rotation speed is equivalent to the pump rotation speed of the hydraulic pump motor 17 and is a value corresponding to the opening of the descending electromagnetic proportional valve 48. As shown in FIG. 6A, a direct proportional relationship is established between the lowering operation amount and the motor speed (that is, the opening degree of the electromagnetic proportional valve 48 for lowering).
　図６（ｂ）は、モータ回転数とシリンダ流量との関係を示すグラフである。図６（ｂ）の横軸は、電動モータ１８のモータ回転数を示しており、油圧ポンプモータ１７のポンプ回転数と同等であるとみなしてよい。図６（ｂ）の縦軸は、リフトシリンダ４のシリンダ流量であり、フォーク下降速度に対応する値であるとみなしてよい。また、図６（ｂ）の中には、下降操作量が「大」の場合における特性を示すグラフＬ１と、下降操作量が「中」の場合における特性を示すグラフＬ２と、下降操作量が「小」の場合における特性を示すグラフＬ３と、が示されている。グラフＬ１，Ｌ２，Ｌ３から分かるように、下降操作量が大きいほど、シリンダ流量、すなわちフォーク下降速度が速くなるように制御が行われる。なお、図６（ａ）に示すように操作量は、運転者のレバー操作によって無段階で設定可能であるが、図６（ｂ）では説明のために、「大」「中」「小」の三段階の場合を例にしている。 FIG. 6B is a graph showing the relationship between the motor speed and the cylinder flow rate. The horizontal axis of FIG. 6B indicates the motor rotation speed of the electric motor 18 and may be regarded as being equivalent to the pump rotation speed of the hydraulic pump motor 17. The vertical axis in FIG. 6B is the cylinder flow rate of the lift cylinder 4 and may be regarded as a value corresponding to the fork lowering speed. Further, in FIG. 6B, the graph L1 indicating the characteristics when the lowering operation amount is “large”, the graph L2 indicating the characteristics when the lowering operation amount is “medium”, and the lowering operation amount. A graph L3 showing characteristics in the case of “small” is shown. As can be seen from the graphs L1, L2, and L3, the control is performed so that the cylinder flow rate, that is, the fork lowering speed increases as the lowering operation amount increases. As shown in FIG. 6A, the operation amount can be set steplessly by the driver's lever operation. In FIG. 6B, for the sake of explanation, “large”, “medium”, and “small” are used. The three-stage case is taken as an example.
　また、図６（ｂ）には、モータ回転数（ポンプ回転数）と油圧ポンプモータ１７のポンプ流量との関係を示すグラフＬＰが示されている。グラフＬＰに示されるように、モータ回転数と油圧ポンプモータ１７のポンプ流量との間には正比例の関係が成り立つ。フォーク下降操作が単独で行われた場合、各下降操作量に対するモータ回転数指令値は、それぞれグラフＬＰ上のＰ１，Ｐ２，Ｐ３に設定される。例えば、下降操作量が「大」の時にフォーク下降操作が単独で行われる場合であって、積荷荷重が大きく、バイパス用流量制御弁５０が作動油の流量の制御（タンク１９へ作動油を排出する）を行わない場合は、モータ回転数及びシリンダ流量は「Ｐ１」における値となる。 FIG. 6B shows a graph LP indicating the relationship between the motor rotation speed (pump rotation speed) and the pump flow rate of the hydraulic pump motor 17. As shown in the graph LP, a direct proportional relationship is established between the motor rotation speed and the pump flow rate of the hydraulic pump motor 17. When the fork lowering operation is performed independently, the motor rotation speed command value for each lowering operation amount is set to P1, P2, and P3 on the graph LP, respectively. For example, when the lowering operation amount is “large”, the fork lowering operation is performed alone, the load is heavy, and the bypass flow control valve 50 controls the flow rate of the hydraulic oil (discharges the hydraulic oil to the tank 19). If not, the motor rotation speed and cylinder flow rate are the values at “P1”.
　ここで、グラフＬＰよりもモータ回転数が負側（紙面左側）の領域Ｅ１においては、バイパス用流量制御弁５０による流量制御が行われる。すなわち、グラフＬ１，Ｌ２，Ｌ３のうち領域Ｅ１側のグラフＬ１ａ，Ｌ２ａ，Ｌ３ａの部分では、バイパス用流量制御弁５０による流量制御が行われる。このときの回生用流量制御弁８０は「開」の状態となっている。領域Ｅ１では、グラフＬ１ａ，Ｌ２ａ，Ｌ３ａに示すように、下降操作量に応じてシリンダ流量（すなわちフォーク下降速度）が一定となるように、バイパス用流量制御弁５０が、排出する作動油の流量を制御する。例えば、下降操作量「大」で単独下降操作がなされている状態のモータ回転数が「Ｐ１」であって、この状態から第２油圧シリンダ７０の同時操作に移行してモータ回転数が「Ｐ１」より小さい「Ｒ１」となったとする。この場合、電磁比例弁４８の前後の圧力差が小さくなるので、回生用流量制御弁８０の開度が大きくなるとともにバイパス用流量制御弁５０の開度が大きくなって、シリンダ流量の一部がバイパス用流量制御弁５０を介してタンク１９へ排出される。具体的には、グラフＬ１ａとポンプ流量のグラフＬＰとの間の「Ｖ１」に示す流量にかかる作動油が、バイパス用流量制御弁５０によってタンク１９へ排出される。一方、グラフＬＰの「Ｖ２」に示す流量に係る作動油が、油圧ポンプモータ１７の吸込口１７ａへ流れることによって、回生が行われる。 Here, the flow rate control by the bypass flow control valve 50 is performed in the region E1 where the motor rotation speed is more negative than the graph LP (left side of the drawing). That is, in the graphs L1, L2, and L3, the flow control by the bypass flow control valve 50 is performed in the graphs L1a, L2a, and L3a on the region E1 side. At this time, the regenerative flow control valve 80 is in an “open” state. In the region E1, as shown in the graphs L1a, L2a, and L3a, the flow rate of the hydraulic oil discharged by the bypass flow control valve 50 so that the cylinder flow rate (that is, the fork lowering speed) becomes constant according to the lowering operation amount. To control. For example, the motor rotational speed in the state where the lowering operation amount is “large” and the single lowering operation is performed is “P1”, and the state shifts from this state to the simultaneous operation of the second hydraulic cylinder 70 and the motor rotational speed is “P1”. “R1” smaller than “”. In this case, since the pressure difference before and after the electromagnetic proportional valve 48 becomes smaller, the opening degree of the regenerative flow control valve 80 becomes larger and the opening degree of the bypass flow control valve 50 becomes larger, so that a part of the cylinder flow rate is reduced. It is discharged to the tank 19 via the bypass flow control valve 50. Specifically, hydraulic oil corresponding to the flow rate indicated by “V 1” between the graph L 1 a and the pump flow rate graph LP is discharged to the tank 19 by the bypass flow control valve 50. On the other hand, regeneration is performed by the hydraulic oil relating to the flow rate indicated by “V2” in the graph LP flowing into the suction port 17a of the hydraulic pump motor 17.
　グラフＬＰよりもモータ回転数が正側（紙面右側）の領域Ｅ２においては、回生用流量制御弁８０による流量制御が行われる。すなわち、グラフＬ１，Ｌ２，Ｌ３のうち領域Ｅ２側のグラフＬ１ｂ，Ｌ２ｂ，Ｌ３ｂ及びグラフＬ１ｃ，Ｌ２ｃ，Ｌ３ｃの部分では、回生用流量制御弁８０による流量制御が行われる。このときのバイパス用流量制御弁５０は「閉」の状態となっている。領域Ｅ２では、グラフＬ１ｃ，Ｌ２ｃ，Ｌ３ｃに示すように、下降操作量に応じてシリンダ流量（すなわちフォーク下降速度）が一定となるように、回生用流量制御弁８０が、油圧ポンプモータ１７の吸込口１７ａへ流れる作動油の流量を制御する。グラフＬ１ｃ，Ｌ２ｃ，Ｌ３ｃの部分では、モータ回転数に対応するポンプ流量と、一定に保たれているシリンダ流量の差分は、油圧ポンプモータ１７がタンク１９から油圧配管２０を介して作動油を引っ張ることで補われる。従って、グラフＬ１ｃ，Ｌ２ｃ，Ｌ３ｃの部分では、回生は生じていない。グラフＬ１ｃ，Ｌ２ｃ，Ｌ３ｃの部分におけるシリンダ流量（すなわちフォーク下降速度）は、グラフＬ１ａ，Ｌ２ａ，Ｌ３ａの部分におけるシリンダ流量（すなわちフォーク下降速度）よりも高く設定されている。すなわち、回生用流量制御弁８０によって制御可能な作動油の流量は、バイパス用流量制御弁によって制御可能な作動油の流量よりも多く設定されている。 The flow rate control by the regenerative flow rate control valve 80 is performed in the region E2 in which the motor rotational speed is on the positive side (right side of the drawing) from the graph LP. That is, in the graphs L1, L2, L3, the flow rate control by the regenerative flow control valve 80 is performed in the graphs L1b, L2b, L3b and the graphs L1c, L2c, L3c on the region E2 side. The bypass flow control valve 50 at this time is in a “closed” state. In the region E2, as shown in the graphs L1c, L2c, and L3c, the regenerative flow control valve 80 causes the suction of the hydraulic pump motor 17 so that the cylinder flow rate (that is, the fork lowering speed) becomes constant according to the lowering operation amount. The flow rate of the hydraulic oil flowing to the port 17a is controlled. In the graphs L1c, L2c, and L3c, the difference between the pump flow rate corresponding to the motor rotation speed and the cylinder flow rate kept constant is that the hydraulic pump motor 17 pulls the hydraulic oil from the tank 19 via the hydraulic pipe 20. It is supplemented by that. Therefore, regeneration does not occur in the graphs L1c, L2c, and L3c. The cylinder flow rate (that is, the fork lowering speed) in the graphs L1c, L2c, and L3c is set higher than the cylinder flow rate (that is, the fork lowering speed) in the graphs L1a, L2a, and L3a. That is, the flow rate of the hydraulic oil that can be controlled by the regenerative flow control valve 80 is set to be larger than the flow rate of the hydraulic oil that can be controlled by the bypass flow control valve.
　グラフＬ１ｂ，Ｌ２ｂ，Ｌ３ｂの部分では、モータ回転数の増加に伴い、シリンダ流量がポンプ流量のグラフＬＰに沿って僅かに立ち上がるように、回生用流量制御弁８０の絞り具合が調整されている。グラフＬ１ｂ，Ｌ２ｂ，Ｌ３ｃの部分では回生が生じている。グラフＬ１ｂ，Ｌ２ｂ，Ｌ３ｂの部分は、バイパス用流量制御弁５０による流量制御から回生用流量制御弁８０による流量制御へ移行する際のバッファ部として機能する。 In the graphs L1b, L2b, and L3b, the degree of throttling of the regenerative flow control valve 80 is adjusted so that the cylinder flow rate slightly rises along the pump flow rate graph LP as the motor rotation speed increases. Regeneration occurs in the graphs L1b, L2b, and L3c. The portions of the graphs L1b, L2b, and L3b function as a buffer unit when shifting from the flow control by the bypass flow control valve 50 to the flow control by the regenerative flow control valve 80.
　リフトシリンダ４の下降操作に加え、第２油圧シリンダ７０を同時に操作し、且つ、下降必要回転数よりも第２油圧シリンダ７０の必要回転数の方が大きい場合、モータ回転数が大きくなり、領域Ｅ２側の制御がなされる。例えば、下降操作量「大」で単独下降操作がなされている状態のモータ回転数が「Ｐ１」であって、この状態から第２油圧シリンダ７０の同時操作がなされてモータ回転数が「Ｐ１」よりも大きい「Ｒ２」となったとする。この場合、電磁比例弁４８の前後の圧力差が大きくなるので、バイパス用流量制御弁５０の開度が小さくなるとともに回生用流量制御弁８０の開度が小さくなってシリンダ流量はグラフＬ１ｃに対応する値となる。すなわち、下降速度が大きく変化することが抑制される。一方、モータ回転数「Ｒ２」の場合のポンプ流量とシリンダ流量の間の「Ｖ３」に係る流量の作動油は、油圧ポンプモータ１７によって油圧配管２０を介してタンク１９から吸い上げられる。 When the second hydraulic cylinder 70 is operated simultaneously in addition to the lowering operation of the lift cylinder 4 and the required rotational speed of the second hydraulic cylinder 70 is larger than the required rotational speed of the lowering, the motor rotational speed increases and the region E2 side control is performed. For example, the motor rotational speed in the state where the lowering operation amount is “large” and the single lowering operation is performed is “P1”, and from this state, the second hydraulic cylinder 70 is operated simultaneously and the motor rotational speed is “P1”. It is assumed that “R2” is larger than that. In this case, since the pressure difference before and after the electromagnetic proportional valve 48 increases, the opening of the bypass flow control valve 50 decreases and the opening of the regenerative flow control valve 80 decreases, so that the cylinder flow corresponds to the graph L1c. The value to be That is, a significant change in the descending speed is suppressed. On the other hand, hydraulic fluid having a flow rate related to “V3” between the pump flow rate and the cylinder flow rate at the motor rotation speed “R2” is sucked up from the tank 19 via the hydraulic pipe 20 by the hydraulic pump motor 17.
　次に、本実施形態の油圧駆動装置１６の動作を図７を参照して説明する。フォーク下降操作が単独で行われた場合は、制御部６４，６５は、力行トルク制限制御目標回転数を０ｒｐｍ近傍に設定し、力行トルク制限制御を行う。なお、前述のように、力行トルク制限制御においては、「回転数偏差＝力行トルク制限制御目標回転数―実回転数」とし、回転数偏差が０になるように力行トルク制限値出力が決定される。図７では３パターンの制御形態が示されているが、いずれの形態においても、フォーク下降操作の単独操作時（以下、単に「単独操作」と称する）は、このような力行トルク制限制御がなされる。 Next, the operation of the hydraulic drive device 16 of this embodiment will be described with reference to FIG. When the fork lowering operation is performed independently, the control units 64 and 65 set the power running torque limit control target rotational speed to be close to 0 rpm and perform the power running torque limit control. As described above, in the power running torque limit control, “rotational speed deviation = power running torque limit control target rotational speed−actual rotational speed” is set, and the power running torque limit value output is determined so that the rotational speed deviation becomes zero. The In FIG. 7, three patterns of control forms are shown. In any form, such a power running torque limit control is performed at the time of the single operation of the fork lowering operation (hereinafter simply referred to as “single operation”). The
　図７に、フォークを所望の速度で下降させるのに必要な「下降必要回転数」よりもフォーク以外のその他アクチュエータを所望の速度で動作させるのに必要な「その他必要回転数」が小さい場合を示す。図７の上段のグラフは、積荷荷重が大きい状態（高負荷状態）であり、十分な回生を行うことができる状態を示している。図７の下段のグラフは、積荷荷重が小さい状態（低負荷状態）であり、十分な回生を行うことができない状態を示している。 FIG. 7 shows a case where the “other required rotational speed” required for operating other actuators other than the fork at a desired speed is smaller than the “required rotational speed required for lowering the fork at the desired speed”. Show. The upper graph in FIG. 7 shows a state where the load is large (high load state) and sufficient regeneration can be performed. The lower graph of FIG. 7 shows a state where the load is small (low load state) and sufficient regeneration cannot be performed.
　図７（ａ）に示す制御形態においては、コントローラ６０は、フォーク下降操作が単独で行われた場合は力行トルク制限制御をＯＮにして、電動モータ１８の指令回転数を力行トルク制限目標回転数（例えば、０ｒｐｍ近傍の値）に設定する。そして、フォーク下降操作と第２油圧シリンダ７０の同時操作（以下、単に「同時操作」と称する）が行われた場合、電動モータ１８の指令回転数は、下降必要回転数と第２油圧シリンダ７０の必要回転数（「その他必要回転数」で示される）の高い方に設定される。また、力行トルク制限制御はＯＦＦ（力行を１００％許可）に設定される。図７（ａ）の上段のグラフに示すように、高負荷状態では、積荷のエネルギーが十分に大きいので、フォーク下降操作を単独で行う単独操作時には、リフトシリンダ４から排出される作動油により電動モータ１８の実回転数が下降必要回転数となって回生が行われる。また、高負荷状態で、単独操作から同時操作へ移行した場合には、電動モータ１８の実回転数は下降必要回転数に制御されて回生が行われるとともに、リフトシリンダ４から排出される作動油によって油圧ポンプモータ１７が駆動されて第２油圧シリンダ７０に作動油が供給される。即ち、この場合は、積荷のエネルギーを有効利用して回生とその他のアクチュエータの動作を行うことができる。一方で、図７（ａ）の下段のグラフに示すように、低負荷状態における単独操作時は、リフトシリンダ４から排出される作動油のエネルギーが小さく電動モータ１８の実回転数は下降必要回転数まで上昇しない。この場合、電磁比例弁４８の前後の圧力差が小さくなるのでバイパス用流量制御弁５０の開度が大きくなって、リフトシリンダ４から排出される作動油の多くがバイパス用流量制御弁５０を介してタンク１９へ排出される。また、低負荷状態で単独操作から同時操作へ移行した時には、力行トルク制限制御がＯＦＦとされるので、電動モータ１８が力行して電動モータ１８の実回転数が下降必要回転数（その他必要回転数よりも高い）となる。この時、バイパス用流量制御弁５０の開度は電磁比例弁４８の圧力差に応じた開度に制御され、リフトシリンダ４から排出される作動油の一部がタンク１９へバイパスされる。 In the control mode shown in FIG. 7A, the controller 60 turns on the power running torque limit control when the fork lowering operation is performed alone, and sets the command rotation speed of the electric motor 18 to the power running torque limit target rotation speed. (For example, a value in the vicinity of 0 rpm). When a fork lowering operation and a simultaneous operation of the second hydraulic cylinder 70 (hereinafter simply referred to as “simultaneous operation”) are performed, the command rotational speed of the electric motor 18 is the required rotational speed and the second hydraulic cylinder 70. Is set to a higher one (represented by “other required rotation number”). Further, the power running torque limit control is set to OFF (power running is 100% permitted). As shown in the upper graph of FIG. 7A, since the energy of the load is sufficiently large in a high load state, the hydraulic oil discharged from the lift cylinder 4 is electrically operated during the single operation for performing the fork lowering operation alone. Regeneration is performed with the actual rotational speed of the motor 18 being the required rotational speed. Further, when the operation is shifted from the single operation to the simultaneous operation in a high load state, the actual rotational speed of the electric motor 18 is controlled to the revolving required rotational speed, regeneration is performed, and the hydraulic oil discharged from the lift cylinder 4 As a result, the hydraulic pump motor 17 is driven and hydraulic oil is supplied to the second hydraulic cylinder 70. That is, in this case, regeneration and other actuator operations can be performed by effectively using the energy of the load. On the other hand, as shown in the lower graph of FIG. 7A, during the single operation in the low load state, the energy of the hydraulic oil discharged from the lift cylinder 4 is small, and the actual rotational speed of the electric motor 18 is required to be lowered. Does not rise to a number. In this case, since the pressure difference before and after the electromagnetic proportional valve 48 becomes smaller, the opening degree of the bypass flow control valve 50 becomes larger, and much of the hydraulic oil discharged from the lift cylinder 4 passes through the bypass flow control valve 50. And discharged to the tank 19. Further, when the operation is shifted from the single operation to the simultaneous operation in the low load state, the power running torque limit control is turned off, so that the electric motor 18 is powered and the actual rotational speed of the electric motor 18 is reduced to the required rotational speed (other necessary rotational speeds). Higher than the number). At this time, the opening degree of the bypass flow control valve 50 is controlled to an opening degree corresponding to the pressure difference of the electromagnetic proportional valve 48, and a part of the hydraulic oil discharged from the lift cylinder 4 is bypassed to the tank 19.
　図７（ｂ）に示す制御形態においては、コントローラ６０は、フォーク下降操作が単独で行われた場合は力行トルク制限制御をＯＮにして、電動モータ１８の指令回転数を力行トルク制限目標回転数（例えば、０ｒｐｍ近傍の値）に設定する。そして、フォーク下降操作と第２油圧シリンダ７０の同時操作が行われた場合には、電動モータ１８の指令回転数は、第２油圧シリンダ７０の必要回転数（その他必要回転数）に設定される。また、力行トルク制限制御はＯＦＦ（力行を１００％許可）に設定される。図７（ｂ）の上段のグラフに示すように、高負荷の単独操作時には電動モータ１８の実回転数が下降必要回転数となって回生が行われる。また、高負荷の同時操作時には、電動モータ１８の実回転数が下降必要回転数よりも小さいその他必要回転数に制御されて回生が行われるとともに、リフトシリンダ４から排出される作動油によって駆動される油圧ポンプモータ１７を介して第２油圧シリンダに作動油が供給される。なお、この時、電磁比例弁４８の前後の圧力差が小さくなることで、バイパス用流量制御弁５０の開度が大きくなって、リフトシリンダ４から排出される作動油の一部がバイパス用流量制御弁５０を介してタンク１９へ排出される。図７（ｂ）の下段のグラフに示すように、低負荷の単独操作時には、電動モータ１８の実回転数は下降必要回転数まで上昇しない。この場合、電磁比例弁４８の前後の圧力差が小さくなり、バイパス用流量制御弁５０の開度が大きくなって、リフトシリンダ４から排出される作動油の多くはバイパス用流量制御弁５０を介してタンク１９へ排出される。また低負荷の同時操作時には、力行トルク制限制御がＯＦＦとされるので電動モータ１８が力行して電動モータ１８の実回転数がその他必要回転数に制御される。この時、バイパス用流量制御弁５０の開度は電磁比例弁４８の圧力差に応じた開度に制御され、リフトシリンダ４から排出される作動油の一部がタンク１９へバイパスされる。 In the control mode shown in FIG. 7B, the controller 60 turns on the power running torque limit control when the fork lowering operation is performed alone, and sets the command rotation speed of the electric motor 18 to the power running torque limit target rotation speed. (For example, a value in the vicinity of 0 rpm). When the fork lowering operation and the second hydraulic cylinder 70 are simultaneously performed, the command rotational speed of the electric motor 18 is set to the necessary rotational speed of the second hydraulic cylinder 70 (other necessary rotational speed). . Further, the power running torque limit control is set to OFF (power running is 100% permitted). As shown in the upper graph of FIG. 7B, regeneration is performed with the actual rotational speed of the electric motor 18 being the required rotational speed at the time of single operation at a high load. Further, during simultaneous operation with a high load, regeneration is performed by controlling the actual rotational speed of the electric motor 18 to other required rotational speed that is smaller than the required rotational speed, and the electric motor 18 is driven by hydraulic oil discharged from the lift cylinder 4. The hydraulic oil is supplied to the second hydraulic cylinder via the hydraulic pump motor 17. At this time, the pressure difference before and after the electromagnetic proportional valve 48 is reduced, so that the degree of opening of the bypass flow control valve 50 is increased, and a part of the hydraulic oil discharged from the lift cylinder 4 is bypassed. It is discharged to the tank 19 through the control valve 50. As shown in the lower graph of FIG. 7B, the actual rotational speed of the electric motor 18 does not increase to the required rotational speed during the single operation with a low load. In this case, the pressure difference before and after the electromagnetic proportional valve 48 becomes smaller, the opening degree of the bypass flow control valve 50 becomes larger, and most of the hydraulic oil discharged from the lift cylinder 4 passes through the bypass flow control valve 50. And discharged to the tank 19. Further, during simultaneous operation with a low load, the power running torque limit control is turned off, so that the electric motor 18 is powered and the actual rotational speed of the electric motor 18 is controlled to the other necessary rotational speed. At this time, the opening degree of the bypass flow control valve 50 is controlled to an opening degree corresponding to the pressure difference of the electromagnetic proportional valve 48, and a part of the hydraulic oil discharged from the lift cylinder 4 is bypassed to the tank 19.
　図７（ｃ）に示す制御形態においては、コントローラ６０は、フォーク下降操作が単独で行われた場合は力行トルク制限制御をＯＮにして、電動モータ１８の指令回転数を力行トルク制限目標回転数（例えば、０ｒｐｍ近傍の値）に設定する。そして、フォーク下降操作と第２油圧シリンダ７０の同時操作が行われた場合、電動モータ１８の指令回転数は、下降必要回転数と第２油圧シリンダ７０の必要回転数（その他必要回転数）の高い方に設定される。また、力行トルク制限制御はＯＮに設定される。力行トルク制限制御目標回転数は、第２油圧シリンダ７０の必要回転数（その他必要回転数）に設定される。図７（ｃ）の上段のグラフに示すように、高負荷の単独操作時には、電動モータ１８の実回転数が下降必要回転数まで上昇して回生が行われる。また、高負荷の同時操作時には、電動モータ１８の実回転数は下降必要回転数に制御されて回生が行われるとともに、リフトシリンダ４から排出される作動油によって油圧ポンプモータ１７が駆動されて第２油圧シリンダ７０に作動油が供給される。図７（ｃ）の下段のグラフに示すように、低負荷の単独操作時には電動モータ１８の実回転数は下降必要回転数まで上昇しない。この場合、電磁比例弁４８の前後の圧力差が小さくなり、バイパス用流量制御弁５０の開度が大きくなって、リフトシリンダ４から排出される作動油の多くはバイパス用流量制御弁５０を介してタンク１９へ排出される。また、低負荷の同時操作時には、力行トルク制限制御がＯＮとなって、電動モータ１８の実回転数はその他必要回転数に制限される。この時、バイパス用流量制御弁５０の開度は電磁比例弁４８の圧力差に応じた開度に制御され、リフトシリンダ４から排出される作動油の一部がタンク１９へバイパスされる。 In the control mode shown in FIG. 7C, the controller 60 turns on the power running torque limit control when the fork lowering operation is performed alone, and sets the command rotation speed of the electric motor 18 to the power running torque limit target rotation speed. (For example, a value in the vicinity of 0 rpm). When the fork lowering operation and the second hydraulic cylinder 70 are simultaneously performed, the command rotational speed of the electric motor 18 is equal to the required rotational speed of the lowering and the required rotational speed of the second hydraulic cylinder 70 (other required rotational speed). Set to the higher one. The power running torque limit control is set to ON. The power running torque limit control target rotational speed is set to a necessary rotational speed of the second hydraulic cylinder 70 (other necessary rotational speed). As shown in the upper graph of FIG. 7 (c), during a single operation with a high load, the actual rotational speed of the electric motor 18 is increased to the required rotational speed for reduction, and regeneration is performed. Further, at the same time when the high load is operated, the actual rotational speed of the electric motor 18 is controlled to the revolving required rotational speed to perform regeneration, and the hydraulic pump motor 17 is driven by the hydraulic oil discharged from the lift cylinder 4 to 2 Hydraulic oil is supplied to the hydraulic cylinder 70. As shown in the lower graph of FIG. 7C, the actual rotational speed of the electric motor 18 does not increase to the required rotational speed during the single operation with a low load. In this case, the pressure difference before and after the electromagnetic proportional valve 48 becomes smaller, the opening degree of the bypass flow control valve 50 becomes larger, and most of the hydraulic oil discharged from the lift cylinder 4 passes through the bypass flow control valve 50. And discharged to the tank 19. Further, during simultaneous operation with a low load, the power running torque limit control is turned ON, and the actual rotational speed of the electric motor 18 is limited to other necessary rotational speeds. At this time, the opening degree of the bypass flow control valve 50 is controlled to an opening degree corresponding to the pressure difference of the electromagnetic proportional valve 48, and a part of the hydraulic oil discharged from the lift cylinder 4 is bypassed to the tank 19.
　また、図７（ａ）、図７（ｂ）及び図７（ｃ）と同様の制御を行う場合であって、下降必要回転数よりもその他必要回転数が大きい場合について説明する。この場合、いずれの制御内容を採用した場合であっても、図８に示すように、実回転数が同様なグラフを描く。図８の上段のグラフに示すように、高負荷状態では、図７（ａ）、図７（ｂ）及び図７（ｃ）の何れの制御を行った場合でも、フォーク下降操作を単独で行う単独操作時には、リフトシリンダ４から排出される作動油により電動モータ１８の実回転数が下降必要回転数となって回生が行われる。また、高負荷状態で、単独操作から同時操作へ移行した場合には、電動モータ１８の実回転数はその他必要回転数に制御されて回生が行われる。また、リフトシリンダ４から排出される作動油によって油圧ポンプモータ１７が駆動されて第２油圧シリンダ７０に作動油が供給される。図８の下段のグラフに示すように、低負荷状態における単独操作時は、リフトシリンダ４から排出される作動油のエネルギーが小さく、電動モータ１８の実回転数は下降必要回転数まで上昇しない。この場合、電磁比例弁４８の前後の圧力差が小さくなるのでバイパス用流量制御弁５０の開度が大きくなって、リフトシリンダ４から排出される作動油の多くがバイパス用流量制御弁５０を介してタンク１９へ排出される。また、低負荷状態で単独操作から同時操作へ移行した時には、いずれの制御を行う場合にも、電動モータ１８の実回転数がその他必要回転数（下降必要回転数より高い）となる。この時、バイパス用流量制御弁５０の開度は電磁比例弁４８の圧力差に応じた開度に制御され、リフトシリンダ４から排出される作動油の一部がタンク１９へバイパスされる。 Further, a case where the same control as in FIGS. 7A, 7B, and 7C is performed and the other necessary rotational speed is larger than the required rotational speed for lowering will be described. In this case, regardless of which control content is employed, a graph having the same actual rotational speed is drawn as shown in FIG. As shown in the upper graph of FIG. 8, in a high load state, the fork lowering operation is performed independently regardless of the control in FIGS. 7 (a), 7 (b), and 7 (c). During the single operation, the hydraulic oil discharged from the lift cylinder 4 causes the actual rotational speed of the electric motor 18 to become the required rotational speed to be regenerated. Further, when the operation is shifted from the single operation to the simultaneous operation in a high load state, the actual rotational speed of the electric motor 18 is controlled to the other necessary rotational speed, and regeneration is performed. Further, the hydraulic pump motor 17 is driven by the hydraulic oil discharged from the lift cylinder 4 and the hydraulic oil is supplied to the second hydraulic cylinder 70. As shown in the lower graph of FIG. 8, during the single operation in the low load state, the energy of the hydraulic oil discharged from the lift cylinder 4 is small, and the actual rotational speed of the electric motor 18 does not increase to the required rotational speed. In this case, since the pressure difference before and after the electromagnetic proportional valve 48 becomes smaller, the opening degree of the bypass flow control valve 50 becomes larger, and much of the hydraulic oil discharged from the lift cylinder 4 passes through the bypass flow control valve 50. And discharged to the tank 19. Further, when shifting from the single operation to the simultaneous operation in the low load state, the actual rotational speed of the electric motor 18 becomes the other necessary rotational speed (higher than the descending necessary rotational speed) in any control. At this time, the opening degree of the bypass flow control valve 50 is controlled to an opening degree corresponding to the pressure difference of the electromagnetic proportional valve 48, and a part of the hydraulic oil discharged from the lift cylinder 4 is bypassed to the tank 19.
　次に、本実施形態に係る荷役車両１の油圧駆動装置１６の作用・効果について説明する。 Next, functions and effects of the hydraulic drive device 16 of the cargo handling vehicle 1 according to the present embodiment will be described.
　本実施形態に係る荷役車両１の油圧駆動装置１６において、リフト操作レバー１１からの作動油を油圧ポンプモータ１７に送るための油圧配管４７から分岐点９１を介して油圧配管４９が接続されている。当該油圧配管４９上には、リフト操作レバー１１からタンク１９に戻る作動油の流量を制御するバイパス用流量制御弁５０が配設されている。また、油圧配管４７において、油圧ポンプモータ１７の吸込口１７ａと分岐点９１との間には、リフト操作レバー１１から油圧ポンプモータ１７へ流れる作動油の流量を制御する回生用流量制御弁８０が配設されている。このような構成によれば、例えば積荷荷重が軽いことによって、油圧ポンプモータ１７に接続される電動モータ１８のモータ回転数が、リフト操作レバー１１の下降操作の操作量に対応するモータ回転数より低い場合（図６の領域Ｅ１側）、バイパス用流量制御弁５０がリフト操作レバー１１からタンク１９へ作動油を戻すことで、下降操作の操作量に応じたフォーク下降速度を得ることができる。一方、下降操作と他の油圧シリンダの操作が同時（且つ、他の油圧シリンダの必要回転数が下降必要回転数より大きい）に行われることで、単独下降時よりもモータ回転数が上がり、油圧ポンプモータ１７の流量が上がる場合（図６の領域Ｅ２側）、回生用流量制御弁８０がリフト操作レバー１１から油圧ポンプモータ１７へ向かう作動油の流量を抑えるように制御することにより、フォーク下降速度が急激に増加することを抑制できる。以上により、昇降用のリフトシリンダ４の下降操作と他の油圧シリンダの操作が同時に行われる場合に、他のアクチュエータを所望の速度で動作させるとともに昇降物リフトを所望の下降速度で下降させることができる。また、同時操作の際に、下降必要回転数の方が、他の油圧シリンダの必要回転数よりも大きい場合であっても、積荷荷重のエネルギーを利用して他の油圧シリンダを作動させることができるので、省エネルギー化を図ることができる。 In the hydraulic drive device 16 of the cargo handling vehicle 1 according to this embodiment, a hydraulic pipe 49 is connected via a branch point 91 from a hydraulic pipe 47 for sending hydraulic oil from the lift operation lever 11 to the hydraulic pump motor 17. . A bypass flow control valve 50 for controlling the flow rate of the hydraulic oil returning from the lift operation lever 11 to the tank 19 is disposed on the hydraulic pipe 49. Further, in the hydraulic pipe 47, a regenerative flow control valve 80 that controls the flow rate of the hydraulic oil flowing from the lift operation lever 11 to the hydraulic pump motor 17 is provided between the suction port 17 a of the hydraulic pump motor 17 and the branch point 91. It is arranged. According to such a configuration, for example, when the load is light, the motor rotation speed of the electric motor 18 connected to the hydraulic pump motor 17 is higher than the motor rotation speed corresponding to the operation amount of the lowering operation of the lift operation lever 11. When it is low (on the side of the region E1 in FIG. 6), the bypass flow control valve 50 returns the hydraulic oil from the lift operation lever 11 to the tank 19, whereby the fork lowering speed corresponding to the operation amount of the lowering operation can be obtained. On the other hand, the lowering operation and the operation of the other hydraulic cylinder are performed simultaneously (and the required rotation speed of the other hydraulic cylinder is larger than the required rotation speed of the other hydraulic cylinder), so that the motor rotation speed is increased compared with the single lowering operation. When the flow rate of the pump motor 17 increases (the region E2 side in FIG. 6), the regenerative flow control valve 80 controls the hydraulic oil flow from the lift operation lever 11 to the hydraulic pump motor 17 so as to lower the fork. The rapid increase in speed can be suppressed. As described above, when the lowering lift cylinder 4 is lowered and the other hydraulic cylinders are simultaneously operated, the other actuators can be operated at a desired speed and the lifted object lift can be lowered at the desired lowering speed. it can. In addition, during simultaneous operation, even if the required rotational speed for lowering is greater than the required rotational speed for other hydraulic cylinders, it is possible to operate other hydraulic cylinders using the load load energy. As a result, energy saving can be achieved.
　本実施形態に係る荷役車両１の油圧駆動装置１６において、回生用流量制御弁８０によって制御可能な作動油の流量は、バイパス用流量制御弁５０によって制御可能な作動油の流量よりも多く設定されている。これにより、所定の下降操作量に対して、回生用流量制御弁８０の制御によってフォーク下降速度を一定に保つ場合（図６のグラフＬ１ｃ，Ｌ２ｃ，Ｌ３ｃの部分）と、バイパス用流量制御弁５０の制御によってフォーク下降速度を一定に保った場合（図６のグラフＬ１ａ，Ｌ２ａ，Ｌ３ａの部分）とを比較すると、回生用流量制御弁８０の制御によるフォーク下降速度の方を高くすることができる。これにより、モータ回転数が上がることで、バイパス用流量制御弁５０による制御から回生用流量制御弁８０による制御へ移行するに、モータ回転数に伴ってフォーク下降速度が部分的に上がる移行部分（図６に示すグラフＬ１ｂ，Ｌ２ｂ，Ｌ３ｂの部分）を設けることができる。このような移行部分を設けることで、バイパス用流量制御弁５０による制御から回生用流量制御弁８０による制御へ急激に変化することを抑制できる。例えば、同時操作ではなく温度変化などの影響によってわずかにモータ回転速度が上がったような場合にも、ただちに制御が切り替わる場合は、不要なタイミングで回生が行われなくなることで、回生効率が低下してしまう。バッファ部として機能する移行部分を設けることで、そのような回生効率の低下を抑制できる。 In the hydraulic drive device 16 of the cargo handling vehicle 1 according to the present embodiment, the flow rate of the hydraulic fluid that can be controlled by the regenerative flow control valve 80 is set to be larger than the flow rate of the hydraulic fluid that can be controlled by the bypass flow control valve 50. ing. Accordingly, when the fork descending speed is kept constant by controlling the regenerative flow control valve 80 with respect to a predetermined lowering operation amount (the portions of the graphs L1c, L2c, and L3c in FIG. 6), the bypass flow control valve 50 is used. As compared with the case where the fork descending speed is kept constant by the control (the portions of the graphs L1a, L2a, L3a in FIG. 6), the fork descending speed by the control of the regenerative flow control valve 80 can be made higher. . As a result, when the motor rotational speed is increased, the transition from the control by the bypass flow control valve 50 to the control by the regenerative flow control valve 80 is performed. Graphs L1b, L2b, and L3b shown in FIG. 6) can be provided. By providing such a transition portion, it is possible to suppress abrupt change from the control by the bypass flow control valve 50 to the control by the regenerative flow control valve 80. For example, even if the motor rotation speed slightly increases due to temperature changes, etc., instead of simultaneous operation, if the control is switched immediately, regeneration will not be performed at unnecessary timing, reducing the regeneration efficiency. End up. By providing the transition portion that functions as the buffer unit, such a decrease in regeneration efficiency can be suppressed.
　本実施形態に係る荷役車両１の油圧駆動装置１６において、電磁比例弁４８の前後の圧力差に基づいて、回生用流量制御弁８０は作動油の流量を制御する。これにより、回生用流量制御弁は、下降操作の操作量に応じたフォーク下降速度で制御することができる。 In the hydraulic drive device 16 of the cargo handling vehicle 1 according to the present embodiment, the regenerative flow control valve 80 controls the flow rate of the hydraulic oil based on the pressure difference before and after the electromagnetic proportional valve 48. Thereby, the regenerative flow control valve can be controlled at a fork lowering speed corresponding to the operation amount of the lowering operation.
　本実施形態に係る荷役車両１の油圧駆動装置１６において、電磁比例弁４８の前後の圧力差に基づいて、バイパス用流量制御弁５０は作動油の流量を制御する。これにより、回生用流量制御弁は、下降操作の操作量に応じたフォーク下降速度で制御することができる。 In the hydraulic drive device 16 of the cargo handling vehicle 1 according to the present embodiment, the bypass flow control valve 50 controls the flow rate of the hydraulic oil based on the pressure difference before and after the electromagnetic proportional valve 48. Thereby, the regenerative flow control valve can be controlled at a fork lowering speed corresponding to the operation amount of the lowering operation.
　以上、本発明に係る荷役車両の油圧駆動装置の好適な実施形態について幾つか説明してきたが、本発明は、上記実施形態に限定されるものではない。 Although several preferred embodiments of the hydraulic drive device for a cargo handling vehicle according to the present invention have been described above, the present invention is not limited to the above embodiment.
　上述の実施形態では、第２油圧シリンダとして、ティルトシリンダ、ＰＳシリンダ、及びアタッチメントシリンダが設けられている。しかし、第２油圧シリンダは少なくとも一本あればよく、一部は省略されてよい。例えば、上記実施形態では、アタッチメント及びパワーステアリングが搭載されているが、本発明の油圧駆動装置は、アタッチメント及びパワーステアリングが搭載されていないフォークリフトにも適用可能である。また、本発明の油圧駆動装置は、フォークリフト以外のバッテリ式の荷役車両であれば適用可能である。 In the above-described embodiment, a tilt cylinder, a PS cylinder, and an attachment cylinder are provided as the second hydraulic cylinder. However, at least one second hydraulic cylinder may be provided, and a part thereof may be omitted. For example, in the above-described embodiment, the attachment and the power steering are mounted, but the hydraulic drive device of the present invention can be applied to a forklift that is not mounted with the attachment and the power steering. The hydraulic drive device of the present invention is applicable to any battery-type cargo handling vehicle other than a forklift.
　１…荷役車両、４…リフトシリンダ（油圧シリンダ）、６…フォーク（昇降物）、１１…リフト操作レバー（第１操作部）、１６…油圧駆動装置、１７…油圧ポンプモータ（油圧ポンプ）、１７ａ…吸込口、１７ｂ…吐出口、１８…電動モータ、４７…油圧配管（第１作動油流路）、４８…フォーク下降用の電磁比例弁（電磁比例弁）、４９…油圧配管（第１作動油流路）、５０…バイパス用流量制御弁（第１流量制御弁）、７０…第２油圧シリンダ、７３…第２操作部、８０…回生用流量制御弁。 DESCRIPTION OF SYMBOLS 1 ... Cargo handling vehicle, 4 ... Lift cylinder (hydraulic cylinder), 6 ... Fork (lifting object), 11 ... Lift operation lever (1st operation part), 16 ... Hydraulic drive device, 17 ... Hydraulic pump motor (hydraulic pump), 17a ... Suction port, 17b ... Discharge port, 18 ... Electric motor, 47 ... Hydraulic piping (first hydraulic fluid flow path), 48 ... Electromagnetic proportional valve (electromagnetic proportional valve) for fork lowering, 49 ... Hydraulic piping (first Hydraulic fluid flow), 50 ... bypass flow control valve (first flow control valve), 70 ... second hydraulic cylinder, 73 ... second operating portion, 80 ... regenerative flow control valve.

Claims (4)

  1. 　作動油の給排により昇降物を昇降させる昇降用の第１油圧シリンダと、
    　前記作動油の給排により前記第１油圧シリンダと異なる動作を行う第２油圧シリンダと、
    　前記第１油圧シリンダを作動させるための第１操作部と、
    　前記第２油圧シリンダを作動させるための第２操作部と、
    　前記第１油圧シリンダ及び第２油圧シリンダに対する前記作動油の給排を行う油圧ポンプと、
    　前記油圧ポンプに接続されて、電動機または発電機として機能する電動モータと、
    　前記作動油を貯留するタンクと、
    　前記油圧ポンプの吸込口と前記第１油圧シリンダとを接続し、前記第１油圧シリンダからの前記作動油を前記油圧ポンプに送るための第１作動油流路と、
    　前記第１作動油流路上の分岐点と前記タンクとを接続し、前記第１油圧シリンダからの前記作動油を前記タンクに戻すための第２作動油流路と、
    　前記第２作動油流路上に配設され、前記第１油圧シリンダから前記タンクに戻る前記作動油の流量を制御する第１流量制御弁と、
    　前記第１作動油流路において、前記油圧ポンプの前記吸込口と前記分岐点との間に配設され、前記第１油圧シリンダから前記油圧ポンプへ流れる前記作動油の流量を制御する第２流量制御弁と、を備え、
    　前記第１操作部による下降操作と前記第２操作部の操作が同時に行われる際に、前記第１操作部の単独操作時よりもモータ回転数が上昇して前記油圧ポンプの流量が多くなる場合、前記第２流量制御弁が前記第１油圧シリンダから前記油圧ポンプへ向かう前記作動油の流量を抑えるように制御する
    　荷役車両の油圧駆動装置。     A first lifting / lowering hydraulic cylinder that lifts and lowers the lifting object by supplying and discharging hydraulic oil;
    A second hydraulic cylinder that operates differently from the first hydraulic cylinder by supplying and discharging the hydraulic oil;
    A first operating portion for operating the first hydraulic cylinder;
    A second operating portion for operating the second hydraulic cylinder;
    A hydraulic pump for supplying and discharging the hydraulic oil to and from the first hydraulic cylinder and the second hydraulic cylinder;
    An electric motor connected to the hydraulic pump and functioning as an electric motor or a generator;
    A tank for storing the hydraulic oil;
    A first hydraulic fluid passage for connecting the suction port of the hydraulic pump and the first hydraulic cylinder, and for sending the hydraulic fluid from the first hydraulic cylinder to the hydraulic pump;
    A second hydraulic oil passage for connecting the branch point on the first hydraulic oil passage and the tank, and returning the hydraulic oil from the first hydraulic cylinder to the tank;
    A first flow rate control valve disposed on the second hydraulic oil flow path for controlling the flow rate of the hydraulic oil returning from the first hydraulic cylinder to the tank;
    A second flow rate that is disposed between the suction port of the hydraulic pump and the branch point in the first hydraulic fluid flow path and controls the flow rate of the hydraulic fluid that flows from the first hydraulic cylinder to the hydraulic pump. A control valve,
    When the lowering operation by the first operation unit and the operation of the second operation unit are performed at the same time, the number of rotations of the hydraulic pump is increased and the flow rate of the hydraulic pump is increased compared with the single operation of the first operation unit A hydraulic drive device for a cargo handling vehicle that controls the second flow rate control valve so as to suppress a flow rate of the hydraulic fluid from the first hydraulic cylinder to the hydraulic pump.
  2. 　前記第２流量制御弁によって制御可能な前記作動油の流量は、前記第１流量制御弁によって制御可能な前記作動油の流量よりも多く設定されている、請求項１に記載の荷役車両の油圧駆動装置。 2. The hydraulic pressure of the cargo handling vehicle according to claim 1, wherein a flow rate of the hydraulic oil that can be controlled by the second flow rate control valve is set to be greater than a flow rate of the hydraulic oil that can be controlled by the first flow rate control valve. Drive device.
  3. 　前記第１作動油流路において、前記第１油圧シリンダと前記分岐点との間に配設され、前記第１操作部の下降操作の操作量に応じた開度で開く比例弁と、を更に備え、
    　前記比例弁の前後の圧力差に基づいて、前記第２流量制御弁は前記作動油の流量を制御する、請求項１又は２に記載の荷役車両の油圧駆動装置。     A proportional valve that is disposed between the first hydraulic cylinder and the branch point in the first hydraulic oil flow path and opens at an opening degree corresponding to an operation amount of the lowering operation of the first operation unit; Prepared,
    The hydraulic drive device for a cargo handling vehicle according to claim 1 or 2, wherein the second flow rate control valve controls a flow rate of the hydraulic oil based on a pressure difference before and after the proportional valve.
  4. 　前記第１作動油流路において、前記第１油圧シリンダと前記分岐点との間に配設され、前記第１操作部の下降操作の操作量に応じた開度で開く比例弁と、を更に備え、
    　前記比例弁の前後の圧力差に基づいて、前記第１流量制御弁は前記作動油の流量を制御する、請求項１～３の何れか一項に記載の荷役車両の油圧駆動装置。     A proportional valve that is disposed between the first hydraulic cylinder and the branch point in the first hydraulic oil flow path and opens at an opening degree corresponding to an operation amount of the lowering operation of the first operation unit; Prepared,
    The hydraulic drive system for a cargo handling vehicle according to any one of claims 1 to 3, wherein the first flow control valve controls a flow rate of the hydraulic oil based on a pressure difference before and after the proportional valve.
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