WO2018087898A1 - 作業機械 - Google Patents
作業機械 Download PDFInfo
- Publication number
- WO2018087898A1 WO2018087898A1 PCT/JP2016/083607 JP2016083607W WO2018087898A1 WO 2018087898 A1 WO2018087898 A1 WO 2018087898A1 JP 2016083607 W JP2016083607 W JP 2016083607W WO 2018087898 A1 WO2018087898 A1 WO 2018087898A1
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- WO
- WIPO (PCT)
- Prior art keywords
- pressure
- hydraulic
- relief
- pump
- motor
- Prior art date
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
- F16H61/38—Control of exclusively fluid gearing
- F16H61/40—Control of exclusively fluid gearing hydrostatic
- F16H61/4008—Control of circuit pressure
- F16H61/4017—Control of high pressure, e.g. avoiding excess pressure by a relief valve
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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
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
- F16H61/38—Control of exclusively fluid gearing
- F16H61/40—Control of exclusively fluid gearing hydrostatic
- F16H61/4035—Control of circuit flow
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
- F16H61/38—Control of exclusively fluid gearing
- F16H61/40—Control of exclusively fluid gearing hydrostatic
- F16H61/4157—Control of braking, e.g. preventing pump over-speeding when motor acts as a pump
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
- F16H61/38—Control of exclusively fluid gearing
- F16H61/40—Control of exclusively fluid gearing hydrostatic
- F16H61/42—Control of exclusively fluid gearing hydrostatic involving adjustment of a pump or motor with adjustable output or capacity
- F16H61/421—Motor capacity control by electro-hydraulic control means, e.g. using solenoid valves
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
- F16H61/38—Control of exclusively fluid gearing
- F16H61/40—Control of exclusively fluid gearing hydrostatic
- F16H61/46—Automatic regulation in accordance with output requirements
- F16H61/478—Automatic regulation in accordance with output requirements for preventing overload, e.g. high pressure limitation
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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
- B66F9/02—Stationary loaders or unloaders, e.g. for sacks
- B66F9/04—Stationary loaders or unloaders, e.g. for sacks hydraulically actuated or controlled
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H59/00—Control inputs to control units of change-speed-, or reversing-gearings for conveying rotary motion
- F16H59/36—Inputs being a function of speed
- F16H59/44—Inputs being a function of speed dependent on machine speed of the machine, e.g. the vehicle
Definitions
- the present invention relates to a work machine having a hydraulic pump and a hydraulic motor that forms a closed circuit between the hydraulic pump and is driven by hydraulic oil discharged from the hydraulic pump.
- HST hydrostatic transmission
- the HST includes a variable displacement traveling hydraulic pump driven by an engine and a variable displacement hydraulic motor driven by hydraulic oil discharged from the traveling hydraulic pump in a main hydraulic circuit that is a closed circuit.
- the vehicle is driven by transmitting the driving force of the hydraulic motor to the driving wheels.
- the hydraulic circuit generally includes a relief valve that discharges hydraulic oil when a predetermined pressure is reached so that excessive pressure does not occur.
- Patent Document 1 describes a relief valve that can change a set pressure.
- work machines have mechanical brakes.
- HST work machines having HST.
- the flow of the traveling hydraulic pump is reduced to generate a braking force, but the mechanical brake also generates the braking force at the same time. Due to the response delay of the traveling hydraulic pump, excessive pressure may be generated in the hydraulic oil in the main hydraulic circuit when braking the work machine having the HST.
- An aspect of the present invention aims to suppress an excessive increase in the pressure of hydraulic oil in the main hydraulic circuit during braking of a work machine having an HST.
- a hydraulic pump and a hydraulic motor are configured in a closed circuit by a hydraulic line, a relief valve that is disposed in the hydraulic line and sets a relief pressure of the hydraulic line;
- a relief device comprising: a braking device that brakes the traveling device attached to the hydraulic motor; and an operation mechanism that operates the braking device, and the speed when the traveling device travels is equal to or greater than a predetermined threshold value. Is provided with a work machine in which the first pressure before the braking operation by the operation mechanism is changed to the second pressure lower than the first pressure.
- the relief pressure is A work machine that changes from a second pressure to the first pressure is provided.
- the hydraulic pump and the hydraulic motor are configured in a closed circuit by a hydraulic line, and provided with a relief valve that is disposed in the hydraulic line and sets a relief pressure of the hydraulic line.
- the relief pressure is at least one of a state of an electric system between the hydraulic pump and a control device that controls the hydraulic pump and the hydraulic motor and a state of an electric system between the control device and the hydraulic motor.
- a work machine is provided that is modified in response to
- the relief valve is provided with a work machine capable of changing the relief pressure steplessly.
- the aspect of the present invention can suppress an excessive increase in the pressure of hydraulic oil in the main hydraulic circuit during braking of a work machine having an HST.
- FIG. 1 is a diagram illustrating an overall configuration of a forklift that is an example of a work machine according to an embodiment.
- FIG. 2 is a block diagram showing a control system of the forklift shown in FIG.
- FIG. 3 is a flowchart showing an example of control during braking of the forklift.
- FIG. 4 is a flowchart illustrating an example of processing when an abnormality occurs in the electrical system.
- FIG. 5 is a diagram illustrating an example in which the relief pressure of the relief valve is changed steplessly.
- FIG. 2 is a block diagram showing a control system of the forklift 1 shown in FIG.
- the forklift 1 includes a vehicle body 3 having a drive wheel 2a and a steered wheel 2b, a work implement 5, and mechanical brakes 9F and 9R that are brake devices for braking the drive wheel 2a and the steered wheel 2b.
- the forklift 1 has a front side from the driver seat ST toward the steering member HL, and a rear side from the steering member HL to the driver seat ST.
- the work machine 5 is provided in front of the vehicle body 3.
- the vehicle body 3 is equipped with an engine 4 that is an example of an internal combustion engine, a traveling hydraulic pump 10 that is a variable displacement hydraulic pump that is driven using the engine 4 as a drive source, and a working machine hydraulic pump 16.
- the engine 4 is a diesel engine, for example, it is not limited to this.
- the output shaft 4S of the engine 4 is connected to the working machine hydraulic pump 16.
- the working machine hydraulic pump 16 and the traveling hydraulic pump 10 are connected via a charge pump 15.
- the traveling hydraulic pump 10, the working machine hydraulic pump 16, and the charge pump 15 are driven by the engine 4 through the output shaft 4S to discharge hydraulic oil.
- a hydraulic motor 20 is mounted on the vehicle body 3.
- the hydraulic motor 20 is a variable displacement hydraulic motor.
- the hydraulic motor 20 forms a closed circuit through which hydraulic oil flows with the traveling hydraulic pump 10, and is driven by the hydraulic oil discharged from the traveling hydraulic pump 10 to rotate the driving wheel 2 a that is a wheel.
- the drive wheel 2a is driven by the power generated by the hydraulic motor 20.
- variable displacement traveling hydraulic pump 10 and the variable displacement hydraulic motor 20 are connected in a closed circuit, that is, a closed hydraulic circuit to form an HST.
- the forklift 1 travels by HST.
- each of the traveling hydraulic pump 10 and the working machine hydraulic pump 16 includes a swash plate 10S and a swash plate 16S, and the tilt angle between the swash plate 10S and the swash plate 16S is changed. As a result, the capacity changes.
- the work machine 5 includes a lift cylinder 7 that lifts and lowers a fork 6 on which a load is placed, and a tilt cylinder 8 that tilts the fork 6.
- the driver's seat of the vehicle body 3 is provided with a forward / reverse lever 42a, an inching pedal 40a as a brake operation unit, an accelerator pedal 41a as an accelerator operation unit, and a work machine operation lever for operating the work machine 5.
- the inching pedal 40a is also referred to as a brake pedal.
- the inching pedal 40a changes the inching rate.
- the accelerator pedal 41 a changes the amount of fuel supplied to the engine 4.
- the inching pedal 40a and the accelerator pedal 41a are provided at positions where the operator of the forklift 1 can perform a stepping operation from the driver's seat. In FIG. 1, the inching pedal 40 a and the accelerator pedal 41 a are depicted in an overlapping state.
- the inching pedal 40a is an operation mechanism that operates the mechanical brakes 9F and 9R. That is, when the inching pedal 40a is operated, brake oil is supplied from the master cylinder 40MS shown in FIG. 2 to the mechanical brakes 9F and 9R. The mechanical brakes 9F and 9R supplied with the brake oil generate a braking force on the drive wheel 2a and the steered wheel 2b by the pressure of the supplied brake oil.
- the traveling device of the work machine is the wheel of the forklift 1, more specifically, the drive wheel 2a.
- the drive wheel 2a is attached to the hydraulic motor 20 via an output shaft 20a and a transfer 20b.
- the traveling device is a crawler belt.
- the traveling device varies depending on the type of the work machine, but may be any apparatus that causes the work machine to travel.
- the forklift 1 includes a main hydraulic circuit 100.
- the main hydraulic circuit 100 is a closed circuit including a traveling hydraulic pump 10, a hydraulic motor 20, and a hydraulic supply line 10a and a hydraulic supply line 10b that connect the two. That is, the main hydraulic circuit 100 is configured by configuring the traveling hydraulic pump 10 and the hydraulic motor 20 in a closed circuit by a hydraulic supply line 10a and a hydraulic supply line 10b that are hydraulic lines.
- the traveling hydraulic pump 10 is a device that is driven by the engine 4 to discharge hydraulic oil.
- the traveling hydraulic pump 10 is a variable displacement pump whose capacity can be changed by changing the swash plate tilt angle, for example.
- the method of changing the capacity of the traveling hydraulic pump 10 is not limited to changing the swash plate tilt angle.
- the hydraulic motor 20 is driven by hydraulic oil discharged from the traveling hydraulic pump 10.
- the hydraulic motor 20 is, for example, a variable capacity hydraulic motor having a swash plate 20S and capable of changing the capacity by changing the swash plate tilt angle.
- the method for changing the capacity of the hydraulic motor 20 is not limited to changing the swash plate tilt angle.
- the hydraulic motor 20 may be a fixed capacity hydraulic motor.
- the hydraulic motor 20 has an output shaft 20a connected to the drive wheel 2a via a transfer 20b.
- the hydraulic motor 20 drives the forklift 1 by driving the drive wheels 2a via the transfer 20b.
- the hydraulic motor 20 can switch the rotation direction according to the supply direction of the hydraulic oil discharged from the traveling hydraulic pump 10.
- the forklift 1 moves forward or backward by switching the rotation direction of the hydraulic motor 20.
- the forklift 1 moves forward, and when the hydraulic oil is supplied from the hydraulic supply line 10b to the hydraulic motor 20. It is assumed that the forklift 1 moves backward.
- a portion connected to the hydraulic supply line 10a is an A port 10A
- a portion connected to the hydraulic supply line 10b is a B port 10B.
- the forklift 1 includes a pump capacity setting unit 11, a motor capacity setting unit 21, and a charge pump 15.
- the pump capacity setting unit 11 is provided in the traveling hydraulic pump 10.
- the pump capacity setting unit 11 includes a forward pump electromagnetic proportional control valve 12, a reverse pump electromagnetic proportional control valve 13, and a pump capacity control cylinder 14.
- a command signal is given to the forward pump electromagnetic proportional control valve 12 and the reverse pump electromagnetic proportional control valve 13 from a control device 30 described later.
- the forward pump electromagnetic proportional control valve 12 and the reverse pump electromagnetic proportional control valve 13 supply hydraulic oil to the pump displacement control cylinder 14 or discharge hydraulic oil from the pump displacement control cylinder 14 when a command signal is given.
- the pump displacement control cylinder 14 is operated.
- the pump capacity setting unit 11 is operated by the pump capacity control cylinder 14 in accordance with a command signal given from the control device 30, and the swash plate tilt angle of the traveling hydraulic pump 10 is changed. The capacity of is changed.
- the forward pump electromagnetic proportional control valve 12 and the reverse pump electromagnetic proportional control valve 13 are in accordance with a command signal given from the control device 30 via the signal lines 12c and 13c, and the forward pump electromagnetic proportional control valve 12 and the reverse pump.
- the pump displacement control cylinder 14 is operated.
- the pump displacement control cylinder 14 operates, the displacement of the traveling hydraulic pump 10 is changed.
- the pump capacity control cylinder 14 has a piston 14a housed in a cylinder case 14C.
- the piston 14a reciprocates in the cylinder case 14C when hydraulic oil is supplied to or discharged from the space between the cylinder case 14C and the piston 14a.
- the piston 14a is held at the neutral position when the swash plate tilt angle is zero. For this reason, even if the engine 4 rotates, the amount of hydraulic oil discharged from the traveling hydraulic pump 10 to the hydraulic pressure supply line 10a or the hydraulic pressure supply line 10b of the main hydraulic circuit 100 is zero.
- the motor capacity setting unit 21 is provided in the hydraulic motor 20.
- the motor capacity setting unit 21 includes a motor electromagnetic proportional control valve 22, a motor cylinder control valve 23, and a motor capacity control cylinder 24.
- motor control pressure is supplied from the motor electromagnetic proportional control valve 22 to the motor cylinder control valve 23 to control the motor capacity.
- the cylinder 24 operates.
- the motor capacity control cylinder 24 operates, the swash plate tilt angle of the hydraulic motor 20 changes in conjunction with the movement of the motor capacity control cylinder 24. For this reason, the capacity
- FIG. Specifically, the motor capacity setting unit 21 is configured such that the swash plate tilt angle of the hydraulic motor 20 decreases as the motor control pressure supplied from the motor electromagnetic proportional control valve 22 increases.
- the motor electromagnetic proportional control valve 22 operates the motor electromagnetic proportional control valve 22 by operating the motor electromagnetic proportional control valve 22 in accordance with the command signal given from the control device 30 via the signal line 22c, and the motor capacity.
- the control cylinder 24 is operated. When the motor capacity control cylinder 24 operates, the capacity of the hydraulic motor 20 is changed.
- the charge pump 15 is driven by the engine 4.
- the charge pump 15 supplies pump control pressure to the pump displacement control cylinder 14 via the forward pump electromagnetic proportional control valve 12 and the reverse pump electromagnetic proportional control valve 13 described above.
- the charge pump 15 supplies motor control pressure to the motor cylinder control valve 23 via the motor electromagnetic proportional control valve 22.
- the engine 4 drives the working machine hydraulic pump 16 in addition to the traveling hydraulic pump 10.
- the work machine hydraulic pump 16 supplies hydraulic oil to a lift cylinder 7 and a tilt cylinder 8 which are work actuators for driving the work machine 5.
- the main hydraulic circuit 100 has a relief valve 45.
- the relief valve 45 is disposed between the hydraulic pressure supply line 10 a and the hydraulic pressure supply line 10 b that connect the traveling hydraulic pump 10 and the hydraulic motor 20.
- the relief valve 45 is disposed between the first connection line 10c and the second connection line 10d that connect the hydraulic pressure supply line 10a and the hydraulic pressure supply line 10b.
- the inlet 45i of the relief valve 45 is connected to the first connecting pipe 10c, and the outlet 45e of the relief valve 45 is connected to the second connecting pipe 10d.
- the relief valve 45 is disposed in the hydraulic pressure supply line 10a and the hydraulic pressure supply line 10b via the first connection line 10c and the second connection line 10d.
- the relief valve 45 sets the circuit pressure of the hydraulic line constituting the main hydraulic circuit 100.
- a check valve 50 and a check valve 51 are attached to the first connection pipe line 10c.
- the check valve 50 allows the flow of hydraulic oil from the hydraulic supply line 10a to the hydraulic supply line 10b
- the check valve 51 allows the flow of hydraulic oil from the hydraulic supply line 10b to the hydraulic supply line 10a.
- An inlet 45 i of the relief valve 45 is connected between the check valve 50 and the check valve 51.
- a check valve 52 and a check valve 53 are attached to the second connecting pipeline 10d.
- the check valve 52 allows the flow of hydraulic oil from the hydraulic supply line 10b to the hydraulic supply line 10a
- the check valve 53 allows the flow of hydraulic oil from the hydraulic supply line 10a to the hydraulic supply line 10b.
- An outlet 45 e of the relief valve 45 is connected between the check valve 52 and the check valve 53.
- the relief valve 45 discharges hydraulic fluid in the main hydraulic circuit 100 between the traveling hydraulic pump 10 and the hydraulic motor 20. More specifically, when a relief pressure that is a preset set pressure is applied to the relief valve 45, the inlet 45i and the outlet 45e are connected, and hydraulic oil flows from the inlet 45i to the outlet 45e.
- the relief pressure is a pressure when the relief valve 45 discharges hydraulic oil.
- the relief valve 45 can change the relief pressure.
- the relief valve 45 has an elastic member 45S for determining the relief pressure.
- the relief valve 45 When the force generated by the pressure of the hydraulic oil acting on the relief valve 45 from the inlet 45i becomes larger than the force generated by the elastic member 45S, the relief valve 45 is opened. That is, the inlet 45i and the outlet 45e are connected. The pressure at which the relief valve 45 opens is the relief pressure.
- the relief pressure is changed by changing the force generated by the elastic member 45 ⁇ / b> S by the adjusting device 46.
- the elastic member 45S is a spring that generates a repulsive force when compressed. When the adjusting device 46 changes the length of the spring that is the elastic member 45S, the force generated by the elastic member 45S changes.
- the adjusting device 46 is a solenoid valve.
- the adjusting device 46 is controlled by the control device 30.
- the adjustment device 46 is supplied with hydraulic oil from the charge pump 15 via the oil passage 15a.
- the adjusting device 46 operates, there are two states, a first state and a second state.
- the adjusting device 46 is supplied with the hydraulic oil supplied from the charge pump 15 in the first state to the relief valve 45, and passes through the hydraulic oil supplied from the charge pump 15 in the second state.
- the elastic member 45S In a state where hydraulic oil is supplied from the adjusting device 46 to the relief valve 45, the elastic member 45S has a first length.
- the elastic member 45S does not receive a force due to the pressure of the hydraulic fluid, and thus changes to a second length longer than the first length. Since the force generated by the elastic member 45S is smaller in the first length than in the second length, the first pressure that is the relief pressure corresponding to the first length is the second pressure. It is higher than the second pressure, which is the relief pressure corresponding to the length, and the second pressure is lower than the first pressure. Thus, the relief valve 45 changes the relief pressure in two stages.
- the relief valve 45 When the pressure of the hydraulic oil in the hydraulic pressure supply line 10a becomes higher than the pressure of the hydraulic oil in the hydraulic pressure supply line 10b and becomes equal to or higher than the relief pressure of the relief valve 45, the relief valve 45 is opened.
- the hydraulic fluid in the hydraulic supply line 10a flows through the first connection line 10c, the check valve 50, the relief valve 45, the second connection line 10d, and the check valve 53 to the hydraulic supply line 10b and is discharged.
- the relief valve 45 When the pressure of the hydraulic oil in the hydraulic pressure supply line 10b becomes higher than the pressure of the hydraulic oil in the hydraulic pressure supply line 10a and exceeds the relief pressure of the relief valve 45, the relief valve 45 is opened.
- the hydraulic oil in the hydraulic supply line 10b flows through the first connection line 10c, the check valve 51, the relief valve 45, the second connection line 10d, and the check valve 52 to the hydraulic supply line 10a and is discharged.
- the relief valve 45 suppresses an excessive increase in the pressure of hydraulic oil on the inlet side and the outlet side of the traveling hydraulic pump 10 and the hydraulic motor 20.
- the relief pressure of the relief valve 45 is changed according to the operating state of the inching pedal 40a.
- the relief pressure of the relief valve 45 is at least one of the state of the electrical system between the control device 30 and the traveling hydraulic pump 10 and the state of the electrical system between the control device 30 and the hydraulic motor 20. It changes according to one side.
- the relief pressure during operation of the forklift 1 is normally the first pressure, and is changed to the second pressure when the relief pressure changing condition is satisfied. The relief pressure is changed from the second pressure to the first pressure when the condition for canceling the change of the relief pressure is satisfied after the relief pressure is changed to the second pressure.
- the forklift 1 includes an inching potentiometer (brake potentiometer) 40 that is an operation amount detector of a braking device, an accelerator potentiometer 41 that is an operation amount detector of an accelerator, a forward / reverse lever switch 42 that is a detector of a direction of travel, an engine rotation A sensor 43r and a vehicle speed sensor 43v are provided.
- an inching potentiometer (brake potentiometer) 40 that is an operation amount detector of a braking device
- an accelerator potentiometer 41 that is an operation amount detector of an accelerator
- a forward / reverse lever switch 42 that is a detector of a direction of travel
- an engine rotation A sensor 43r and a vehicle speed sensor 43v are provided.
- the inching potentiometer 40 detects and outputs the operation amount when the inching pedal 40a is operated.
- the operation amount of the inching pedal 40a is the inching operation amount Is.
- the inching operation amount Is output from the inching potentiometer 40 is input to the control device 30.
- the inching operation amount Is may be referred to as an inching stroke Is.
- the accelerator potentiometer 41 outputs the operation amount Aop of the accelerator pedal 41a when the accelerator pedal 41a is operated.
- the operation amount Aop of the accelerator pedal 41a is also referred to as an accelerator opening Aop.
- the accelerator opening Aop output from the accelerator potentiometer 41 is input to the control device 30.
- the forward / reverse lever switch 42 is a selection switch for switching the traveling direction of the forklift 1.
- the forward / reverse lever switch 42 is applied.
- Information indicating the traveling direction of the forklift 1 selected by the forward / reverse lever switch 42 is given to the control device 30 as selection information.
- the traveling direction of the forklift 1 selected by the forward / reverse lever switch 42 includes both the direction in which the forklift 1 will travel and the direction in which the forklift 1 actually travels.
- the engine rotation sensor 43 r detects the actual rotation speed of the engine 4.
- the rotation speed of the engine 4 detected by the engine rotation sensor 43r is an actual engine rotation speed Nr.
- Information indicating the actual engine rotation speed Nr is input to the control device 30.
- the rotational speed of the engine 4 is the rotational speed of the output shaft 4S of the engine 4 per unit time.
- the vehicle speed sensor 43v is a device that detects the actual vehicle speed Vc that is the speed at which the forklift 1, that is, the traveling device travels.
- Control device 30 includes a processing unit 30C and a storage unit 30M.
- the control device 30 is a device that includes, for example, a computer and executes various processes related to the control of the forklift 1.
- the processing unit 30C is, for example, a device that combines a processor such as a CPU (Central Processing Unit) and a memory.
- the processing unit 30C controls the operation of the main hydraulic circuit 100 by reading a computer program stored in the storage unit 30M for controlling the main hydraulic circuit 100 and executing instructions described therein. .
- the storage unit 30M stores the above-described computer program, data necessary for controlling the main hydraulic circuit 100, and the like.
- the storage unit 30M is, for example, a ROM (Read Only Memory), a storage device, or a device that combines these.
- the control device 30 is electrically connected to various sensors such as an inching potentiometer 40, an accelerator potentiometer 41, a forward / reverse lever switch 42, an engine rotation sensor 43r, and a vehicle speed sensor 43v. Based on the input signals from these various sensors, the control device 30 receives command signals from the forward pump electromagnetic proportional control valve 12, the reverse pump electromagnetic proportional control valve 13, the motor electromagnetic proportional control valve 22, and the adjusting device 46. Generate. The control device 30 gives the generated command signal to the forward pump electromagnetic proportional control valve 12, the reverse pump electromagnetic proportional control valve 13, the motor electromagnetic proportional control valve 22, and the adjusting device 46.
- various sensors such as an inching potentiometer 40, an accelerator potentiometer 41, a forward / reverse lever switch 42, an engine rotation sensor 43r, and a vehicle speed sensor 43v. Based on the input signals from these various sensors, the control device 30 receives command signals from the forward pump electromagnetic proportional control valve 12, the reverse pump electromagnetic proportional control valve 13, the motor electromagnetic proportional control valve 22, and the adjusting device 46
- the control device 30 is supplied with electric power from the power supply 44 through the electric wire 44W.
- the control device 30 operates with power supplied from the power supply 44.
- the power supply 44 is exemplified by a secondary battery mounted on the forklift 1.
- control during braking of the forklift 1 will be described.
- the inching potentiometer 40 detects the operating state of the inching pedal 40a and gives it to the control device 30.
- the operation state of the inching pedal 40a is exemplified by the operation amount and the operation speed of the inching pedal 40a, but is not limited thereto.
- the control device 30 reduces the flow rate of the traveling hydraulic pump 10 based on the operating state of the inching pedal 40a received from the inching potentiometer 40.
- the flow rate of the traveling hydraulic pump 10 is decreased, the flow rate of the hydraulic motor 20 becomes larger than the flow rate of the traveling hydraulic pump 10, so the forklift 1 is decelerated.
- the mechanical brakes 9F and 9R generate braking force.
- the rotational speed of the drive wheel 2a and the rotational speed of the hydraulic motor 20 are rapidly decreased by the mechanical brakes 9F and 9R.
- the speed at which the flow rate of the traveling hydraulic pump 10 is decreased may not be in time for the decrease in the rotational speed of the hydraulic motor 20. That is, at the time of braking, the response of the traveling hydraulic pump 10 may not be in time.
- the flow rate of the traveling hydraulic pump 10 instantaneously becomes excessive with respect to the flow rate of the hydraulic motor 20, and the hydraulic oil suddenly flows between the discharge side of the traveling hydraulic pump 10 and the inflow side of the hydraulic motor 20.
- the pressure increases. Since there is a response delay of the relief valve 45, the pressure of the hydraulic oil existing between the discharge side of the traveling hydraulic pump 10 and the inflow side of the hydraulic motor 20 in the main hydraulic circuit 100 may increase excessively. is there.
- the relief pressure of the relief valve 45 is set to an inching pedal in order to suppress an excessive increase in the pressure of hydraulic oil existing between the discharge side of the traveling hydraulic pump 10 and the inflow side of the hydraulic motor 20. It changes according to the operation state of 40a. Specifically, when the inching pedal 40a is in an operation state indicating sudden braking, the relief pressure is changed from the first pressure to a second pressure lower than the first pressure. This change is performed by the control device 30.
- the control device 30 determines the operation state of the inching pedal 40a from the detection result of the inching potentiometer 40. If the operation state of the inching pedal 40a indicates sudden braking, the control device 30 generates a command value for setting the adjustment device 46 in the second state. To the adjusting device 46. Receiving this command, the adjusting device 46 changes from the first state to the second state, so that the relief pressure changes from the first pressure to the second pressure. Then, the relief valve 45 opens at a second pressure lower than the first pressure, so that the inflow side of the traveling hydraulic pump 10 and the hydraulic motor are between the discharge side of the traveling hydraulic pump 10 and the inflow side of the hydraulic motor 20. The hydraulic oil is discharged between the 20 discharge sides. For this reason, it is suppressed that the hydraulic oil in the main hydraulic circuit 100, specifically, the hydraulic oil existing between the discharge side of the traveling hydraulic pump 10 and the inflow side of the hydraulic motor 20 increases excessively. .
- the adjustment device 46 When the operating state of the inching pedal 40a does not indicate sudden braking, the adjustment device 46 is in the first state, so that the relief pressure is a first pressure higher than the second pressure. For this reason, when the forklift 1 is not in a state of sudden braking, the possibility that acceleration and traction force of the forklift 1 are reduced by opening the relief valve 45 is suppressed.
- a braking operation that is, an operation for generating a braking force to the mechanical brakes 9F and 9R to the inching pedal 40a.
- the relief pressure changes from the first pressure Prh to the second pressure Prl or is maintained at the first pressure Prh depending on the operation state of the inching pedal 40a.
- at least a braking operation needs to be applied to the inching pedal 40a.
- FIG. 3 is a flowchart showing an example of control during braking of the forklift 1.
- step S101 when the control device 30 detects a braking operation from the inching potentiometer 40 (step S101, Yes), in step S102, the control device 30 determines whether or not a relief pressure changing condition is satisfied.
- the control device 30 does not detect a braking operation from the inching potentiometer 40 (No in step S101), the control during braking ends.
- Condition (5) “Shuttle” means that the direction of the forward / reverse lever 42a and the direction in which the forklift 1 travels are different. Condition (5) does not hold when the forward / reverse lever 42a is reverse, but the forklift 1 is moving forward.
- the operation amount of the inching pedal 40a that is, the inching stroke Is before the first time before the determination, is less than a first threshold which is a predetermined threshold.
- the speed at which the inching stroke Is increases is equal to or higher than a second threshold that is a predetermined threshold.
- the inching stroke Is at the time of determination is equal to or greater than a third threshold that is a predetermined threshold.
- the actual vehicle speed Vc of the forklift 1 is equal to or higher than a fourth threshold which is a predetermined threshold.
- the forward / reverse lever 42a is on the reverse side and is not in the shuttle.
- step S103 the control device 30 sets the relief pressure Pr to the second pressure Prl.
- the control device 30 sets the relief device Pr to the second pressure Prl by setting the adjustment device 46 to the second state.
- step S102, No the control during braking ends.
- step S104 the control device 30 determines whether or not a condition for canceling the change of the relief pressure is satisfied.
- Condition (A) means that the state in which the amount of braking operation applied to the inching pedal 40a has decreased has continued for a predetermined time.
- Condition (B) is established in a state where the forward / reverse lever 42a is reverse, but the forklift 1 is moving forward.
- the state where the inching stroke Is is less than the third threshold is continued for a second time which is a predetermined time.
- the forward / reverse lever 42a is on the reverse side and in the shuttle.
- step S105 the control device 30 sets the relief pressure Pr to the first pressure Prh.
- the control device 30 sets the relief pressure Pr to the first pressure Prh by setting the adjustment device 46 to the first state. Thereafter, the control during braking ends.
- the control device 30 performs the above-described control, so that the hydraulic oil existing in the main hydraulic circuit 100, specifically, between the discharge side of the traveling hydraulic pump 10 and the inflow side of the hydraulic motor 20 is controlled. Suppresses the possibility of excessive pressure rise.
- the condition for changing the relief pressure is satisfied when all of the conditions (1) to (5) are satisfied, but whether or not the braking is sudden is determined if there is an operating state of the inching pedal 40a. it can. For this reason, the control device 30 determines that the condition for changing the relief pressure is satisfied when all of the conditions (1), (2), and (3), which are conditions related to the operation state of the inching pedal 40a, are satisfied. May be.
- Condition (4) is that when the speed at which the forklift 1 travels is equal to or higher than a fourth threshold, which is a predetermined threshold, the relief pressure Pr is changed from the first pressure Prh to the second pressure Prl, and a braking operation is given.
- the relief pressure is made smaller than before being applied.
- Condition (5) is for changing the relief pressure Pr from the first pressure Prh to the second pressure Prl when the forklift 1 travels backward.
- the relief pressure Pr When the relief pressure does not have to be changed to the second pressure Prh according to the condition (5), the relief pressure Pr is maintained at the first pressure Prh. Therefore, the acceleration and traction force of the forklift 1 is increased by opening the relief valve 45. The possibility of lowering can be reduced.
- condition (5) may not be added to the condition for changing the relief pressure according to the specifications of the forklift 1, and the content may be changed. Since the condition (B) included in the condition for releasing the change of the relief pressure corresponds to the condition (5) of the relief pressure change condition, the condition (B) also changes the relief pressure according to the specifications of the forklift 1. It may not be added to the conditions, and the content may be changed.
- the relief pressure Pr becomes the second pressure after the state in which the operation amount of the braking operation applied to the inching pedal 40a has been reduced continues for the second time.
- the pressure Prl is changed to the first pressure Prh.
- the electrical system of the main hydraulic circuit 100 includes a first system that is an electrical system between the control device 30 and the traveling hydraulic pump 10 and a second system that is an electrical system between the control device 30 and the hydraulic motor 20. .
- the control device 30 controls the traveling hydraulic pump 10 by giving a command signal which is an electric signal to the forward pump electromagnetic proportional control valve 12 and the reverse pump electromagnetic proportional control valve 13 through the signal lines 12c and 13c. To do.
- the first system includes the control circuit 30, the signal lines 12c and 13c, and the electric circuits of the forward pump electromagnetic proportional control valve 12 and the reverse pump electromagnetic proportional control valve 13.
- the control device 30 controls the hydraulic motor 20 by giving a command signal, which is an electrical signal, to the motor electromagnetic proportional control valve 22 via the signal line 22c.
- the second system includes an electric circuit included in the control device 30, the signal line 22c, and the motor electromagnetic proportional control valve 22.
- the control device 30 changes the relief pressure Pr according to at least one of the state of the first system and the state of the second system. For example, when the controller 30 detects that at least one of the signal line 12c and the signal line 13c of the first system is disconnected and grounded, or the signal line 22c of the second system is disconnected and grounded, the relief device 30 The pressure Pr is changed from the first pressure Prh to the second pressure Prl.
- the relief valve 45 When the relief pressure Pr is lowered to the second pressure Prl, the relief valve 45 is easier to open than in the case of the first pressure Prh.
- the relief valve 45 When the relief valve 45 is opened because the relief pressure Pr has decreased to the second pressure Prl, the hydraulic oil existing between the inflow side of the traveling hydraulic pump 10 and the discharge side of the hydraulic motor 20 passes through the relief valve 45. And discharged between the discharge side of the traveling hydraulic pump 10 and the inflow side of the hydraulic motor 20. As a result, a sudden increase in the pressure of the hydraulic oil existing between the inflow side of the traveling hydraulic pump 10 and the discharge side of the hydraulic motor 20 is avoided, so that rapid deceleration of the forklift 1 is suppressed.
- the adjustment device 46 enters the second state when the control device 30 is turned off.
- the control device 30 is turned off, and the adjustment device 46 is in the second state.
- the relief pressure becomes the second pressure Prl
- the relief valve 45 becomes easier to open than in the case of the first pressure Prh.
- the relief valve 45 is opened because the relief pressure Pr has decreased to the second pressure Prl, the hydraulic oil existing between the inflow side of the traveling hydraulic pump 10 and the discharge side of the hydraulic motor 20 passes through the relief valve 45. And discharged between the discharge side of the traveling hydraulic pump 10 and the inflow side of the hydraulic motor 20.
- a sudden increase in the pressure of the hydraulic oil existing between the inflow side of the traveling hydraulic pump 10 and the discharge side of the hydraulic motor 20 is avoided, so that rapid deceleration of the forklift 1 is suppressed.
- FIG. 4 is a flowchart showing a processing example when an abnormality occurs in the electrical system.
- step S201 when the control device 30 detects that an abnormality, for example, at least one of a ground fault and a disconnection has occurred in at least one of the first system and the second system (step S201, Yes), in step S202, the relief pressure Pr is set to the second pressure Prl.
- the controller 30 does not detect that an abnormality has occurred in at least one of the first system and the second system (No in step S201), the control device 30 ends the process.
- the control device 30 can suppress sudden deceleration of the forklift 1 by changing the relief pressure Pr to the second pressure Prl when an abnormality occurs in at least one of the first system and the second system.
- FIG. 5 is a diagram showing an example in which the relief pressure Pr of the relief valve 45 is changed steplessly.
- the relief pressure Pr of the relief valve 45 can be changed in two stages of the first pressure Prh or the second pressure Prl, but may be changed infinitely.
- the length of the elastic member 45S is steplessly changed by a pressure changing cylinder 48 driven by the electromagnetic proportional control valve 47. As a result, the relief pressure Pr is changed steplessly.
- the electromagnetic proportional control valve 47 is supplied with hydraulic oil discharged from the charge pump 15 shown in FIG. 2 from the oil passage 15a.
- the electromagnetic proportional control valve 47 supplies the hydraulic oil supplied from the oil passage 15 a to the pressure change cylinder 48 or discharges the hydraulic oil from the pressure change cylinder 48. Then, the pressure changing cylinder 48 is operated.
- the control device 30 can change the relief pressure Pr steplessly according to the operating state of the inching pedal 40a.
- the control device 30 can finely adjust the second pressure Prl in consideration of the temperature of the hydraulic oil, or can change the second pressure Prl according to the operation amount and operation speed of the inching pedal 40a. .
- the control device 30 can realize more appropriate and precise control than when the relief pressure Pr is changed in two stages.
- the work machine is not limited to a forklift, and may be a wheel loader, a grader, a bulldozer, a dump truck, or the like.
- the traveling hydraulic pump 10 and the hydraulic motor 20 may not be variable displacement types.
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Abstract
Description
図1は、実施形態に係る作業機械の一例であるフォークリフト1の全体構成を示す図である。図2は、図1に示したフォークリフト1の制御系統を示すブロック図である。フォークリフト1は、駆動輪2a及び操向輪2bを有した車体3と、作業機5と、駆動輪2a及び操向輪2bを制動する制動装置である機械式ブレーキ9F,9Rと、を有する。フォークリフト1は、運転席STから操舵部材HLへ向かう側が前であり、操舵部材HLから運転席STへ向かう側が後である。作業機5は、車体3の前方に設けられる。
図2に示されるように、フォークリフト1は、主油圧回路100を備えている。主油圧回路100は、走行用油圧ポンプ10と、油圧モータ20と、両者を接続する油圧供給管路10a及び油圧供給管路10bとを含んだ閉回路である。つまり、主油圧回路100は、走行用油圧ポンプ10及び油圧モータ20を、油圧管路である油圧供給管路10a及び油圧供給管路10bによって閉回路に構成したものである。走行用油圧ポンプ10は、エンジン4によって駆動されて作動油を吐出する装置である。実施形態において、走行用油圧ポンプ10は、例えば、斜板傾転角を変更することによって容量を変更することのできる可変容量型のポンプである。走行用油圧ポンプ10の容量を変更する方式は、斜板傾転角を変更するものには限定されない。
フォークリフト1は、ポンプ容量設定ユニット11、モータ容量設定ユニット21及びチャージポンプ15を有する。ポンプ容量設定ユニット11は、走行用油圧ポンプ10に設けられる。ポンプ容量設定ユニット11は、前進用ポンプ電磁比例制御バルブ12、後進用ポンプ電磁比例制御バルブ13及びポンプ容量制御シリンダ14を備える。ポンプ容量設定ユニット11は、前進用ポンプ電磁比例制御バルブ12及び後進用ポンプ電磁比例制御バルブ13に、後述する制御装置30から指令信号が与えられる。前進用ポンプ電磁比例制御バルブ12及び後進用ポンプ電磁比例制御バルブ13は、指令信号が与えられると、ポンプ容量制御シリンダ14に作動油を供給、又はポンプ容量制御シリンダ14から作動油を排出させて、ポンプ容量制御シリンダ14を動作させる。ポンプ容量設定ユニット11は、制御装置30から与えられた指令信号に応じてポンプ容量制御シリンダ14が動作し、走行用油圧ポンプ10の斜板傾転角が変化することによって、走行用油圧ポンプ10の容量が変更される。
モータ容量設定ユニット21は、油圧モータ20に設けられる。モータ容量設定ユニット21は、モータ電磁比例制御バルブ22、モータ用シリンダ制御バルブ23及びモータ容量制御シリンダ24を備えている。モータ容量設定ユニット21では、モータ電磁比例制御バルブ22に制御装置30から指令信号が与えられると、モータ電磁比例制御バルブ22からモータ用シリンダ制御バルブ23にモータ制御圧力が供給されて、モータ容量制御シリンダ24が動作する。モータ容量制御シリンダ24が動作すると、モータ容量制御シリンダ24の動きに連動して油圧モータ20の斜板傾転角が変化することになる。このため、制御装置30からの指令信号に応じて油圧モータ20の容量が変更されることになる。詳細には、モータ容量設定ユニット21は、モータ電磁比例制御バルブ22から供給されるモータ制御圧力が増加するにしたがって、油圧モータ20の斜板傾転角が減少するようになっている。
主油圧回路100は、リリーフ弁45を有する。リリーフ弁45は、走行用油圧ポンプ10と油圧モータ20とを接続する油圧供給管路10aと油圧供給管路10bとの間に配置される。詳細には、リリーフ弁45は、油圧供給管路10aと油圧供給管路10bとを接続する第1連結管路10cと第2連結管路10dとの間に配置される。リリーフ弁45の入口45iは第1連結管路10cに接続され、リリーフ弁45の出口45eは第2連結管路10dに接続される。このようにリリーフ弁45は、第1連結管路10cと第2連結管路10dとを介して、油圧供給管路10a及び油圧供給管路10bに配設される。リリーフ弁45は、主油圧回路100を構成する油圧管路の回路圧力を設定する。
フォークリフト1は、制動装置の操作量検出器であるインチングポテンショメータ(ブレーキポテンショメータ)40、アクセルの操作量検出器であるアクセルポテンショメータ41、走行方向の指示の検出器である前後進レバースイッチ42、エンジン回転センサ43r及び車速センサ43vを備えている。
制御装置30は、処理部30Cと記憶部30Mとを含む。制御装置30は、例えば、コンピュータを備え、フォークリフト1の制御に関する各種の処理を実行する装置である。処理部30Cは、例えば、CPU(Central Processing Unit)のようなプロセッサとメモリとを組合せた装置である。処理部30Cは、記憶部30Mに記憶されている、主油圧回路100を制御するためのコンピュータプログラムを読み込んでこれに記述されている命令を実行することにより、主油圧回路100の動作を制御する。記憶部30Mは、前述したコンピュータプログラム及び主油圧回路100の制御に必要なデータ等を記憶している。記憶部30Mは、例えば、ROM(Read Only Memory)、ストレージデバイス又はこれらを組合せた装置である。
次に、フォークリフト1の制動時における制御について説明する。フォークリフト1のオペレータがインチングペダル40aを踏み込むと、インチングポテンショメータ40はインチングペダル40aの操作状態を検出し、制御装置30に与える。インチングペダル40aの操作状態は、インチングペダル40aの操作量及び操作速度が例示されるが、これらには限定されない。
(1)判定時よりも第1の時間前におけるインチングペダル40aの操作量、すなわちインチングストロークIsが所定の閾値である第1の閾値未満であること。
(2)インチングストロークIsの増加する速度が、所定の閾値である第2の閾値以上であること。
(3)判定時におけるインチングストロークIsが所定の閾値である第3の閾値以上であること。
(4)フォークリフト1の実車速Vcが所定の閾値である第4の閾値以上であること。
(5)前後進レバー42aが後進側、かつシャトル中でないこと。
(A)インチングストロークIsが第3の閾値未満である状態が、予め定められた時間である第2の時間、継続すること。
(B)前後進レバー42aが後進側、かつシャトル中であること。
次に、制御装置30と主油圧回路100との間の電気系統に異常が発生した場合の制御について説明する。主油圧回路100の電気系統は、制御装置30と走行用油圧ポンプ10との間の電気系統である第1系統及び制御装置30と油圧モータ20との間の電気系統である第2系統がある。
図5は、リリーフ弁45のリリーフ圧力Prを無段階に変更する例を示す図である。これまでの説明において、リリーフ弁45のリリーフ圧力Prは、第1圧力Prh又は第2圧力Prlの2段階に変更できたが、無段階に変更できてもよい。リリーフ弁45は、電磁比例制御バルブ47によって駆動される圧力変更シリンダ48によって、弾性部材45Sの長さが無段階に変更される。その結果、リリーフ圧力Prは無段階に変更される。
2a 駆動輪
4 エンジン
5 作業機
6 フォーク
9F,9R 機械式ブレーキ
10 走行用油圧ポンプ
12 前進用ポンプ電磁比例制御バルブ
13 後進用ポンプ電磁比例制御バルブ
11 ポンプ容量設定ユニット
12c,13c,22c 信号線
14 ポンプ容量制御シリンダ
15 チャージポンプ
16 作業機用油圧ポンプ
20 油圧モータ
21 モータ容量設定ユニット
22 モータ電磁比例制御バルブ
23 モータ用シリンダ制御バルブ
24 モータ容量制御シリンダ
30 制御装置
30C 処理部
30M 記憶部
40 インチングポテンショメータ
40MS マスタシリンダ
40a インチングペダル
42 前後進レバースイッチ
42a 前後進レバー
45 リリーフ弁
45e 出口
45i 入口
45S 弾性部材
46 調整装置
47 電磁比例制御バルブ
48 圧力変更シリンダ
100 主油圧回路
Pr リリーフ圧力
Prh 第1圧力
Prl 第2圧力
Claims (4)
- 油圧ポンプ及び油圧モータを油圧管路によって閉回路に構成し、前記油圧管路に配設され、前記油圧管路のリリーフ圧力を設定するリリーフ弁と、
前記油圧モータに取り付けられた走行装置を制動する制動装置と、
前記制動装置を操作する操作機構と、を備え、
前記走行装置が走行するときの速度が所定の閾値以上である場合、前記リリーフ圧力は、前記操作機構による制動操作がされる前の第1圧力から、前記第1圧力よりも低い第2圧力に変更される、作業機械。 - 前記操作機構に与えられた前記制動操作の操作量が減少した状態が、予め定められた時間継続した後に、前記リリーフ圧力が前記第2圧力から前記第1圧力に変更される、請求項1に記載の作業機械。
- 油圧ポンプ及び油圧モータを油圧管路によって閉回路に構成し、前記油圧管路に配設され、前記油圧管路のリリーフ圧力を設定するリリーフ弁を備え、
前記リリーフ圧力が、前記油圧ポンプ及び前記油圧モータを制御する制御装置と前記油圧ポンプとの間の電気系統の状態及び前記制御装置と前記油圧モータとの間の電気系統の状態のうち少なくとも一方に応じて変更される、作業機械。 - 前記リリーフ弁は、前記リリーフ圧力を無段階に変更できる、請求項1から請求項3のいずれか1項に記載の作業機械。
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US15/511,342 US20180231118A1 (en) | 2016-11-11 | 2016-11-11 | Work machine |
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JP7197433B2 (ja) | 2019-06-11 | 2022-12-27 | 株式会社小松製作所 | 作業車両の制御装置、作業車両、および作業車両の制御方法 |
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JP2010270767A (ja) * | 2009-05-19 | 2010-12-02 | Kobe Steel Ltd | 油圧式走行装置の制御装置 |
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2016
- 2016-11-11 JP JP2016574018A patent/JP6335340B1/ja active Active
- 2016-11-11 CN CN201680003132.7A patent/CN108291635A/zh active Pending
- 2016-11-11 WO PCT/JP2016/083607 patent/WO2018087898A1/ja active Application Filing
- 2016-11-11 US US15/511,342 patent/US20180231118A1/en not_active Abandoned
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JPS6435169A (en) * | 1987-07-31 | 1989-02-06 | Honda Motor Co Ltd | Hydraulic control device for vehicle continuously variable transmission |
JPH01166162U (ja) * | 1988-04-27 | 1989-11-21 | ||
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JPH09317878A (ja) * | 1996-05-30 | 1997-12-12 | Kayaba Ind Co Ltd | 車両用流体圧駆動装置 |
JP2005308113A (ja) * | 2004-04-22 | 2005-11-04 | Shin Caterpillar Mitsubishi Ltd | 油圧式走行車両の異常動作防止装置 |
US20100050624A1 (en) * | 2006-11-15 | 2010-03-04 | Robert Bosch Gmbh | Hydrostatic travel drive having two hydraulic motors |
Also Published As
Publication number | Publication date |
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US20180231118A1 (en) | 2018-08-16 |
JPWO2018087898A1 (ja) | 2018-11-08 |
CN108291635A (zh) | 2018-07-17 |
JP6335340B1 (ja) | 2018-05-30 |
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