WO2020235242A1 - 油圧システム - Google Patents
油圧システム Download PDFInfo
- Publication number
- WO2020235242A1 WO2020235242A1 PCT/JP2020/015737 JP2020015737W WO2020235242A1 WO 2020235242 A1 WO2020235242 A1 WO 2020235242A1 JP 2020015737 W JP2020015737 W JP 2020015737W WO 2020235242 A1 WO2020235242 A1 WO 2020235242A1
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- WIPO (PCT)
- Prior art keywords
- valve
- command
- spool
- pressure reducing
- electromagnetic proportional
- Prior art date
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B13/00—Details of servomotor systems ; Valves for servomotor systems
- F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
- F15B13/04—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor
- F15B13/044—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor operated by electrically-controlled means, e.g. solenoids, torque-motors
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B13/00—Details of servomotor systems ; Valves for servomotor systems
- F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
- F15B13/04—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor
- F15B13/042—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor operated by fluid pressure
- F15B13/043—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor operated by fluid pressure with electrically-controlled pilot valves
- F15B13/0435—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor operated by fluid pressure with electrically-controlled pilot valves the pilot valves being sliding valves
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
- F15B11/08—Servomotor systems without provision for follow-up action; Circuits therefor with only one servomotor
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B13/00—Details of servomotor systems ; Valves for servomotor systems
- F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
- F15B13/025—Pressure reducing valves
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B15/00—Fluid-actuated devices for displacing a member from one position to another; Gearing associated therewith
- F15B15/18—Combined units comprising both motor and pump
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B19/00—Testing; Calibrating; Fault detection or monitoring; Simulation or modelling of fluid-pressure systems or apparatus not otherwise provided for
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B20/00—Safety arrangements for fluid actuator systems; Applications of safety devices in fluid actuator systems; Emergency measures for fluid actuator systems
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B20/00—Safety arrangements for fluid actuator systems; Applications of safety devices in fluid actuator systems; Emergency measures for fluid actuator systems
- F15B20/008—Valve failure
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B19/00—Testing; Calibrating; Fault detection or monitoring; Simulation or modelling of fluid-pressure systems or apparatus not otherwise provided for
- F15B19/005—Fault detection or monitoring
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/30—Directional control
- F15B2211/32—Directional control characterised by the type of actuation
- F15B2211/329—Directional control characterised by the type of actuation actuated by fluid pressure
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/60—Circuit components or control therefor
- F15B2211/63—Electronic controllers
- F15B2211/6303—Electronic controllers using input signals
- F15B2211/6306—Electronic controllers using input signals representing a pressure
- F15B2211/6316—Electronic controllers using input signals representing a pressure the pressure being a pilot pressure
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/60—Circuit components or control therefor
- F15B2211/635—Circuits providing pilot pressure to pilot pressure-controlled fluid circuit elements
- F15B2211/6355—Circuits providing pilot pressure to pilot pressure-controlled fluid circuit elements having valve means
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/80—Other types of control related to particular problems or conditions
- F15B2211/85—Control during special operating conditions
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/80—Other types of control related to particular problems or conditions
- F15B2211/86—Control during or prevention of abnormal conditions
- F15B2211/863—Control during or prevention of abnormal conditions the abnormal condition being a hydraulic or pneumatic failure
- F15B2211/8636—Circuit failure, e.g. valve or hose failure
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
- F15B2211/00—Circuits for servomotor systems
- F15B2211/80—Other types of control related to particular problems or conditions
- F15B2211/865—Prevention of failures
Definitions
- the present invention relates to a hydraulic system in which the movement of a solenoid valve is electronically controlled by a control device.
- a hydraulic system that operates a multi-control valve using a solenoid valve is known, and one example thereof is the hydraulic drive system of Patent Document 1.
- the hydraulic drive system of Patent Document 1 includes a swivel control valve (multi-control valve), and operates on a swivel motor by changing the position of the spool of the swivel control valve according to the pilot pressure output from the solenoid valve. It controls the flow of oil.
- the solenoid valve used in the hydraulic drive system of Patent Document 1 is configured as follows, for example. That is, in the solenoid valve, the spool is slidably inserted into the housing, and the spool moves by receiving the thrust from the solenoid.
- the solenoid valve changes the pilot pressure output from the spool as it moves, and changes the position of the spool of the swivel control valve. In this way, the solenoid valve moves the spool by the solenoid, but the thrust from the solenoid is not large.
- an object of the present invention is to provide a hydraulic system capable of suppressing the occurrence of malfunction of the solenoid valve due to contamination.
- the hydraulic system according to the first invention has a valve spool that slides in the housing, an electromagnetic valve that moves the valve spool in response to an input operation command, and a control that outputs an operation command to the solenoid valve.
- the control device includes a device, and when a predetermined condition is satisfied, the control device gives an operation command to the solenoid valve to reciprocate the valve spool from a fully open position or a fully closed position.
- the valve spool can be intentionally reciprocated from the fully open position or the fully closed position by satisfying a predetermined condition. As a result, it is possible to clean the solenoid valve for removing contamination and the like that have entered between the valve spool and the housing, and it is possible to suppress the occurrence of malfunction of the solenoid valve due to contamination.
- the solenoid valve is an electromagnetic switching valve
- the operation command includes an open command for positioning the valve spool in a fully open position and a close command for positioning the valve spool in a fully closed position.
- the control device reciprocates the valve spool by reversing the operation command of either the open command or the close command continuously given to the solenoid switching valve to the other operation command for a short specified time. It is preferable to exercise.
- the electromagnetic switching valve can be cleaned to remove contamination and the like that have entered between the valve spool and the housing.
- the solenoid valve is an electromagnetic proportional pressure reducing valve
- the operation command includes a predetermined command for positioning the valve spool in the fully open position or the fully closed position, and the control device satisfies the above conditions.
- the valve spool is reciprocated by continuously changing the predetermined command given to the solenoid proportional pressure reducing valve to a specific operation command for a specified time.
- the electromagnetic proportional pressure reducing valve can be cleaned to remove contamination and the like that have entered between the valve spool and the housing.
- the pair of solenoid valves is provided, and each of the pair of solenoid valves is an electromagnetic proportional pressure reducing valve, and the secondary pressure output from each is opposed to the control spool of the control valve.
- the actuation command includes a predetermined command to position the valve spool in the fully open position or the fully closed position, and the control device continues to be electromagnetically proportional when the conditions are met. It is preferable that the predetermined command given to the pressure reducing valve is changed to a specific operation command for a specified time so that the secondary pressure of each of the pair of solenoid proportional pressure reducing valves is the same and the valve spool is reciprocated.
- a switching valve provided on the upstream side of the solenoid proportional pressure reducing valve and capable of shutting off the flow of hydraulic oil to the solenoid proportional pressure reducing valve is provided, and the condition is that the switching valve operates the solenoid valve. It is preferable to include that the flow of oil is blocked.
- the valve spool of the electromagnetic proportional pressure reducing valve can be reciprocated in a state where pressure oil is not supplied to the electromagnetic proportional pressure reducing valve. Therefore, when the electromagnetic proportional pressure reducing valve is reciprocated, an undesired pilot pressure is applied from the electromagnetic proportional pressure reducing valve. Can be suppressed from being output.
- the solenoid valve is an electromagnetic proportional pressure reducing valve, and is arranged so that a secondary pressure output from the electromagnetic proportional pressure reducing valve acts on the control spool of the control valve, and the control valve is a secondary valve.
- the control device has a dead zone that does not operate when the pressure is less than a predetermined value, and the control device issues an operation command for reciprocating the valve spool so that the secondary pressure output from the solenoid proportional pressure reducing valve becomes less than the predetermined value. It is preferable to do so.
- the valve spool of the electromagnetic proportional control valve can be reciprocated without moving the control spool of the control valve. Therefore, it is possible to prevent the control spool of the control valve from making an undesired movement during the reciprocating motion.
- control device reciprocates the valve spool by outputting a step-like operation command to the electromagnetic proportional pressure reducing valve.
- valve spool can be reciprocated with a larger excitation force, so that the spool can be moved even if contamination is slightly bitten. Thereby, a higher cleaning effect can be achieved.
- the condition preferably includes a state in which no oil flow flows to the downstream side of the solenoid valve.
- the pressure sensor provided on the downstream side of the solenoid valve is further provided, and the control device operates the valve spool based on the pressure detected by the pressure sensor and the operation command output to the solenoid valve. It is preferable to detect defects.
- the hydraulic system can detect mechanical malfunctions such as spool sticks.
- the hydraulic system according to the second invention includes a pilot pump that discharges pilot oil, and an electromagnetic proportional pressure reducing valve that is connected to the pilot pump via a pilot passage and outputs a secondary pressure according to an input pressure reducing command.
- a control valve that controls the flow of pressure oil flowing through the hydraulic actuator according to the secondary pressure output from the electromagnetic proportional pressure reducing valve, and the pilot passage that is interposed in the pilot passage and is input in response to a switching command.
- the electromagnetic switching valve includes a control device that outputs a pressure reducing command to the electromagnetic proportional pressure reducing valve and outputs a switching command to the electromagnetic switching valve, and the electromagnetic switching valve slides in the first housing.
- It has a moving first valve spool, and the pilot passage is shut off by moving the first valve spool in response to an input switching command, and the electromagnetic proportional pressure reducing valve slides in the second housing. It has a second valve spool, adjusts the secondary pressure to be output by moving the second valve spool in response to an input decompression command, and the control device is fully opened when a predetermined first condition is satisfied.
- a switching command is given to the electromagnetic switching valve to reciprocate the first valve spool from the position or the fully closed position and a predetermined second condition is satisfied
- the second valve spool reciprocates from the fully open position or the fully closed position.
- a pressure reducing command is given to the electromagnetic proportional pressure reducing valve so as to cause the pressure reduction.
- the valve spools of the electromagnetic proportional pressure reducing valve and the electromagnetic switching valve can be intentionally reciprocated from the fully open position or the closed position by satisfying the first and second conditions, respectively. Contamination and the like that have entered between each valve spool and the housing can be removed. As a result, it is possible to suppress the occurrence of malfunctions in the electromagnetic proportional pressure reducing valve and the electromagnetic switching valve due to contamination.
- the switching command includes an open command for positioning the first valve spool in the fully open position and a closing command for positioning the first valve spool in the fully closed position, and the decompression command is for the second valve spool.
- the control device is one of an open command and a closed command continuously given to the electromagnetic switching valve.
- valve spools of the electromagnetic proportional pressure reducing valve and the electromagnetic switching valve can be intentionally reciprocated from the fully open position or the fully closed position, and each valve spool and the housing can be reciprocated. Cleaning can be performed to remove contamination and the like that have entered. Cleaning can be performed on the electromagnetic proportional pressure reducing valve to remove contamination and the like that have entered between the valve spool and the housing.
- the pair of electromagnetic proportional pressure reducing valves is provided, the control valve has a control spool, and the flow of pressure oil flowing to the hydraulic actuator is controlled according to the position of the control spool.
- Each of the electromagnetic proportional pressure reducing valves moves the control spool by applying the secondary pressure output from each to the control spool in a direction opposite to each other, and the switching command causes the first valve spool to be in the fully open position.
- the control device includes an open command for positioning and a close command for positioning the first valve spool in a fully closed position, and a decompression command includes a predetermined command for positioning the second valve spool in a fully open position or a fully closed position.
- the operation command of either the open command or the close command continuously given to the electromagnetic switching valve is reversed to the other operation command for a short first specified time, and the first operation command is reversed.
- the valve spool is reciprocated and the second condition is satisfied, the predetermined command given to the electromagnetic proportional pressure reducing valve is continuously changed to a specific pressure reducing command for the second specified time, and the pair of electromagnetic proportional pressure reducing pressure is satisfied. It is preferable that the secondary pressure of each valve is the same and the second valve spool is reciprocated.
- valve spools of the electromagnetic proportional pressure reducing valve and the electromagnetic switching valve can be intentionally reciprocated from the fully open position or the closed position, and each of the valve spools is inserted between the valve spool and the housing.
- cleaning can be performed to remove contamination and the like.
- Cleaning can be performed on the electromagnetic proportional pressure reducing valve to remove contamination and the like that have entered between the valve spool and the housing.
- the pair of electromagnetic proportional pressure reducing valves it is possible to perform cleaning on the pair of electromagnetic proportional pressure valves to remove contamination and the like that have entered between the valve spool and the housing without moving the control spool of the control valve. ..
- control valve has a dead zone that does not operate when the secondary pressure is less than a predetermined value, and under the first condition, the secondary pressure output from the electromagnetic proportional pressure reducing valve is less than a predetermined value. It is preferable to include that a decompression command is output.
- the first valve spool of the electromagnetic switching valve can be reciprocated without moving the control spool of the control valve. Therefore, it is possible to prevent the control spool of the control valve from making an undesired movement during the reciprocating motion.
- the second condition preferably includes that the pilot passage is blocked by the electromagnetic switching valve.
- the valve spool of the electromagnetic proportional pressure reducing valve can be reciprocated in a state where pressure oil is not supplied to the electromagnetic proportional pressure reducing valve. Therefore, when the electromagnetic proportional pressure reducing valve is reciprocated, an undesired pilot pressure is applied from the electromagnetic proportional pressure reducing valve. Is output to prevent the control valve from making undesired movements.
- At least one of the first condition and the second condition includes the pilot pump being stopped.
- Vehicles including industrial vehicles and construction vehicles and machines including industrial machines and construction machines are provided with a hydraulic actuator (for example, a hydraulic cylinder and a hydraulic motor, etc.) 2.
- a hydraulic actuator for example, a hydraulic cylinder and a hydraulic motor, etc.
- Various operations can be performed by moving.
- a vehicle or the like is provided with a hydraulic system 1 for supplying hydraulic oil to the hydraulic actuator 2 and moving it, and the hydraulic system 1 of the present embodiment is provided in, for example, a hydraulic excavator.
- the hydraulic system 1 supplies hydraulic oil to, for example, a double-acting hydraulic cylinder 2 provided in a hydraulic excavator.
- the vehicle to which the hydraulic system 1 is applied is not limited to the hydraulic excavator, and the hydraulic actuator 2 is also not limited to the double-acting hydraulic cylinder 2.
- the hydraulic actuator 2 may be a single-acting hydraulic cylinder or a hydraulic motor.
- the hydraulic system 1 will be described.
- the flood control system 1 includes a main pump 11, a multi-control valve 12, a pilot pump 13, a safety lock valve 14, electromagnetic proportional pressure reducing valves 15L and 15R, and a control device 16.
- the main pump 11 is, for example, a variable displacement swash plate pump and is connected to the engine E.
- the main pump 11 is not limited to the swash plate pump, and may be a variable displacement type swash shaft pump.
- the main pump 11 is rotationally driven by the engine E, and the hydraulic oil is discharged by being rotationally driven. A flow rate of the hydraulic oil is discharged according to the tilt angle of the swash plate 11a, and the tilt angle of the swash plate 11a is changed by the regulator 11b. The hydraulic oil discharged in this way is guided to the multi-control valve 12.
- the multi-control valve 12 is a so-called directional control valve, and the direction in which the hydraulic oil flows is switched by moving the spool 12a. More specifically, the multi-control valve 12 is connected to the head side port 2a and the rod side port 2b of the hydraulic cylinder 2 and the tank 17 in addition to the main pump 11, and each of them is connected according to the position of the spool 12a. Switch the connection state. That is, when the spool 12a, which is an example of the control spool, moves from the neutral position M to the first offset position A1, the main pump 11 is connected to the head side port 2a, the rod side port 2b is connected to the tank 17, and the hydraulic cylinder 2 is extended. To do.
- the spool 12a is urged by the two spring members 12L and 12R in a direction opposite to each other, and further, two pilot pressures PL and PR that resist the urging forces of the spring members 12L and 12R and resist each other. Is working. Therefore, the spool 12a moves to a position where the two urging forces and the two pilot pressures PL and PR are balanced, and the hydraulic oil in the direction and flow rate (that is, flow) corresponding to the position of the spool 12a is transferred to the hydraulic cylinder 2. Can be shed. That is, by adjusting the two pilot pressures PL and PR, the extension and contraction of the hydraulic cylinder 2 are switched, and the speed thereof is controlled. Further, the hydraulic system 1 is provided with a pilot pump 13 in order to apply pilot pressures PL and PR to the spool 12a.
- the pilot pump 13 is a fixed-capacity pump (for example, a gear pump) and is rotationally driven by the engine E.
- the pilot pump 13 discharges a predetermined amount of pilot oil into the pilot passage 18, and a safety lock valve 14 is interposed in the pilot passage 18.
- the safety lock valve 14 is a so-called electromagnetic switching valve and can shut off the pilot passage 18.
- the safety lock valve 14 is configured as shown in FIG. 2, for example, and has a housing 21, a spool 22, a solenoid 23, and a spring member 24. Note that FIG. 2 shows only an outline of the configuration of the safety lock valve 14, and does not limit the configuration of the safety lock valve 14 to that. Hereinafter, the configuration of the safety lock valve 14 shown in FIG. 2 will be described.
- Each port 21a, 21b, 21c are formed in the housing 21, which is an example of the first housing, and each port 21a, 21b, 21c is a pilot pump 13, a tank 17, and two electromagnetic proportional pressure reducing valves described later. It is connected to 15L and 15R respectively.
- the spool 22 is housed in the housing 21 so as to be slidable (that is, reciprocally movable) in the axial direction thereof, and the spool 22 is connected to three ports 21a, 21b, 21c by changing its position. The state can be switched. More specifically, the spool 22, which is an example of the first valve spool, has an annular passage 22a.
- the annular passage 22a is formed by being recessed in the middle portion in the axial direction of the spool 22 over the entire circumference, and is always connected to the third port 21c. Further, the spool 22 has a plurality of notches 22b and 22c in the round shoulder portion formed having a large diameter with respect to the intermediate portion in the axial direction. The notches 22b and 22c are opened to the first port 21a and the second port 21b according to the position of the spool 22, and the ports 21a and 21b are connected to the third port 21c via the communication passage 22a by opening the notches 22b and 22c, respectively. That is, the pilot passage 18 can be blocked or opened by moving the spool 22 (more specifically, moving the spool 22 to the blocking position shown in FIG. 2A and the opening position shown in FIG. 2B, respectively). ..
- the spool 22 that operates in this way is provided with a solenoid 23 to move it.
- the plurality of notches 22b and 22c do not necessarily have to be formed
- the solenoid 23 generates an exciting force in response to a switching command (an example of an operation command) input therein.
- the rod 23a of the solenoid 23 is in contact with the spool 22, and pushes the spool 22 with a thrust corresponding to the exciting force to move the spool 22 toward the open position.
- the spool 22 is provided with a spring member 24, and the spool 22 receives an urging force from the spring member 24 in a direction against the exciting force (thrust) of the solenoid 23 and in a direction toward the breaking position. Therefore, when the exciting force is smaller than the urging force, the spool 22 moves to the blocking position or is held at the blocking position.
- the spool 22 connects the first port 21a to the second port 21b at the shutoff position, so that the downstream side is connected to the tank 17.
- the first port 21a is connected to the third port 21c
- the downstream side is connected to the pump 11, and the pilot oil is guided to the downstream side of the safety lock valve 14.
- the pilot passage 18 is branched into two passage portions 18L and 18R on the downstream side of the safety lock valve 14, and pilot pressures PL and PR are applied to the spool 22 in each of these two passage portions 18L and 18R.
- Electromagnetic proportional pressure reducing valves 15L and 15R are connected respectively to give.
- the electromagnetic proportional pressure reducing valves 15L and 15R reduce the pilot oil to a secondary pressure (that is, pilot pressure PL, PR) based on the pressure reducing command input therein and output the pilot oil.
- the configuration of the electromagnetic proportional pressure reducing valves 15L and 15R is similar to the configuration of the safety lock valve 14, for example, and the configuration will be briefly described below. Further, since the electromagnetic proportional pressure reducing valves 15L and 15R have the same configuration, only one configuration will be described, and the same reference numerals will be given to the other configuration, and the description thereof will be omitted. Further, the configurations of the electromagnetic proportional pressure reducing valves 15L and 15R shown below are merely examples, and are not limited to the configurations, as in the configuration of the safety lock valve 14.
- the first electromagnetic proportional pressure reducing valve 15L has a housing 31, a spool 32, a solenoid 33, and a spring member 34 as shown in FIG.
- the housing 31, which is an example of the second housing, is formed with three ports 31a, 31b, and 31c, each of which is connected to the safety lock valve 14, the tank 17, and the multi-control valve 12.
- the spool 32 is slidably housed in the housing 31 in the axial direction (that is, reciprocally movable), and the spool 32 can be connected to the three ports 31a, 31b, 31c by changing its position. It can be switched.
- the spool 32 which is an example of the second valve spool, is formed with a communication passage 32a and notches 32b and 32c, and the notches 32b and 32c are opened to the first port according to the position of the spool 32. It is connected to 31a and the second port 31b, and the first pilot pressure PL corresponding to the opening degree is output from the third port 31c. That is, the first pilot pressure PL can be adjusted by moving the spool 32, and the spool 32 is provided with a solenoid 33 for adjustment.
- the solenoid 33 generates an exciting force according to the decompression command (an example of the operation command) input therein. Further, the rod 33a of the solenoid 33 is in contact with the spool 32, and pushes the spool 32 with a thrust corresponding to the exciting force to move the spool 32. That is, the spool 32 can move from the fully closed position where the third port 31c is closed to the opening position where the third port 31c opens and the third port 31c opens. Further, the spool 32 is provided with a spring member 34, and receives an urging force from the spring member 34 against the exciting force (thrust) of the solenoid 33. Further, the housing 21 is formed with a return passage 31d.
- the return passage 31d returns the secondary pressure (first pilot pressure PL) into the housing 21 and acts on the spool 32 so as to resist the exciting force of the solenoid 33. Therefore, the spool 32 moves to a position where the exciting force, the urging force, and the secondary pressure are balanced, so that the first pilot pressure PL of the pressure corresponding to the exciting force (that is, according to the decompression command) is electromagnetically proportional. It can be output from the pressure reducing valve 15L. In this way, each of the electromagnetic proportional pressure reducing valves 15L and 15R can output the pilot pressures PL and PR of the pressure corresponding to the pressure reducing command, and as shown in FIG. 1, each of the electromagnetic proportional pressure reducing valves 15L and 15R , It is electrically connected to the control device 16 to input a decompression command there.
- the control device 16 is connected to each of the electromagnetic proportional pressure reducing valves 15L and 15R, and outputs a pressure reducing command (for example, current) to each of the electromagnetic proportional pressure reducing valves 15L and 15R.
- the decompression command which is an example of the operation command, is, for example, a pulse width modulation signal (that is, a PWM signal), and the electromagnetic proportional pressure reducing valves 15L and 15R press the spool 32 with an exciting force according to the duty ratio of the PWM signal.
- the pilot pressures PL and PR are reduced to the desired pressures.
- the spool 32 when a zero signal (predetermined command) having a duty ratio of zero is output from the control device 16, the spool 32 is located at the fully closed position, and the duty ratio is increased from there to increase the exciting force.
- the spool 32 can be moved toward the opening position.
- control device 16 is also electrically connected to the safety lock valve 14, and outputs a switching command to the safety lock valve 14.
- the switching command which is an example of the operation command, is a step-shaped command signal such as ON and OFF, and the spool 22 moves to the fully open position when an ON signal (open command) of a predetermined current is output.
- the electromagnetic proportional pressure reducing valves 15L and 15R are connected to the pump 13.
- the switching signal becomes an OFF signal (close command)
- the spool 22 returns to the fully closed position, and the electromagnetic proportional pressure reducing valves 15L and 15R are connected to the tank 17.
- an operating device (not shown) is connected to the control device 16 in order to input the amount of expansion or contraction of the hydraulic cylinder 2.
- the operating device is, for example, an electric joystick or an operating valve, and outputs an operating signal to the control device 16 according to the operating amount (including the operating direction) of the operating tool such as a lever provided therein.
- the control device 16 creates a decompression command based on this operation signal and outputs it to the electromagnetic proportional pressure reducing valves 15L and 15R.
- the operating device also includes a safety lever, and when the safety lever is operated, the operating device outputs a lock signal to the control device 16. Then, the control device 16 outputs a switching signal (specifically, an OFF signal of zero current) to the safety lock valve 14 to shut off the pilot passage 18.
- the operating device that operates the safety lock valve 14 does not necessarily have to be a safety lever, but may be a switch or the like.
- three pressure sensors 19, 19L and 19R are electrically connected to the control device 16.
- the first pressure sensor 19 outputs a signal corresponding to the pressure of the pilot oil output from the safety lock valve 14 to the control device 16.
- the second and third pressure sensors 19L and 19R output signals corresponding to the secondary pressures of the electromagnetic proportional pressure reducing valves 15L and 15R, that is, the pilot pressures PL and PR to the control device 16.
- the control device 16 detects the respective oil pressures based on the signals from the pressure sensors 19, 19L, and 19R.
- the control device 16 can detect the current (or voltage) output based on each command for the safety lock valve 14 and the electromagnetic proportional pressure reducing valves 15L and 15R, that is, the actual current (or actual voltage).
- the control device 16 outputs a decompression command to any of the two electromagnetic proportional pressure reducing valves 15L and 15R in response to the operation signal from the operating device. For example, when a pressure reducing command is input to the first electromagnetic proportional pressure reducing valve 15L, the first pilot pressure PL is output from the first electromagnetic proportional pressure reducing valve 15L, and the spool 12a moves to the first offset position A1. As a result, the hydraulic cylinder 2 is extended.
- the control device 16 outputs a switching signal (specifically, an OFF signal) to the safety lock valve 14 to shut off the pilot passage 18.
- a switching signal specifically, an OFF signal
- the pilot pressures PL and PR from the electromagnetic proportional pressure reducing valves 15L and 15R can be set to zero regardless of the presence or absence of the operation signal from the operating device.
- the hydraulic cylinder 2 can be prevented from operating when the safety lever is operated or when a failure occurs.
- the hydraulic system 1 configured in this way has the following self-cleaning function. That is, the hydraulic system 1 enters between the spools 22 and 32 and the housing 21 in the solenoid valves such as the safety lock valve 14 and the solenoid proportional pressure reducing valves 15L and 15R, and the notches 22b, 22c, 32b and 32c ( Contamination that is caught in the opening such as the metering part) can be removed.
- the ON signal or the OFF signal that has been continuously input up to that point is turned off for the first specified time (for example, a short time of 0.2 sec or less).
- the spool 22 can be reciprocated from the fully open position to the fully closed position or from the fully closed position to the fully open position.
- the spool 22 can be reciprocated from the fully open position to the fully closed position or from the fully closed position to the fully open position.
- By reciprocating in this way it is possible to positively remove more contamination adhering to the outer peripheral surface of the spool 22, such as being able to scrape the above-mentioned contamination into the communication passage 22a.
- the hydraulic oil can be adapted to the outer peripheral surface of the spool 22.
- the pilot oil can be blended in a wider range, and the lubricity of the spool 22 can be improved. This makes it possible to suppress a decrease in the responsiveness of the safety lock valve 14.
- the control device 16 reciprocates the spool 22 only once, but the spool 22 may be reciprocated twice or more, and may be reciprocated at least once.
- the control device 16 sends the zero signal continuously input until then to a specific pressure reducing command for the second specified time (for example, a short time of 0.2 sec or less). More specifically, the spool 32 is reciprocated from the fully closed position by changing to a stepped signal. In the present embodiment, the spool 32 reciprocates so as to return from the fully closed position to the fully open position and then to the fully closed position, but reciprocates so as to return from the fully open position to the fully closed position and then to the fully open position. It may be.
- the hydraulic oil can be adapted to the outer peripheral surface of the spool 32. That is, the pilot oil can be blended in a wider range, and the lubricity of the spool 32 can be improved. As a result, it is possible to suppress a decrease in the responsiveness of the electromagnetic proportional pressure reducing valves 15L and 15R.
- the spool 32 is reciprocated a plurality of times, but it may be reciprocated once or at least once.
- step S1 which is a start condition satisfaction determination step, it is determined whether or not the control device 16 satisfies a predetermined start condition.
- the start conditions include, for example, that the engine E is in a stopped state (that is, the pilot pump 13 is stopped), that the spool 22 of the safety lock valve 14 is located at the shutoff position, and the like. In the embodiment, only the latter is the starting condition.
- the start condition does not necessarily have to be one of the two described above, and may simply be that power is supplied to the control device 16.
- the control device 16 determines whether or not the start condition is satisfied based on the switching signal output to the safety lock valve 14, and if it is determined that the start condition is not satisfied, the determination is repeated in step S1. On the other hand, if it is determined that the control device 16 satisfies the start condition, the process proceeds to step S2.
- step S2 which is the neutral position determination step, the control device 16 determines whether or not the position of the spool 12a of the multi-control valve 12 is the neutral position M. More specifically, the spool 12a is in the neutral position when the pilot pressures PL and PR are less than the predetermined pressure values because the urging forces of the two spring members 12L and 12R act against each other. It is held at M. That is, the spool 12a has a dead zone in which the pilot pressures PL and PR do not operate when the pressure values are less than a predetermined value, and if the decompression command output to the electromagnetic proportional pressure reducing valves 15L and 15R is less than a predetermined value, the spool 12a It is maintained at the neutral position M.
- the decompression command output from the control device 16 is less than a predetermined value (that is, whether or not the absolute value of the operation amount of the operation device is less than a predetermined amount) (satisfaction of the first condition). (Presence / absence) is determined. If the depressurization command is equal to or greater than a predetermined value, the position of the spool 22 may change when the spool 22 of the safety lock valve 14 is reciprocated. Therefore, the process returns to step S1 assuming that the first condition is not satisfied. On the other hand, if the decompression command is less than a predetermined value, it is assumed that the first condition is satisfied, and the process proceeds to step S3.
- step S3 which is the first cleaning step
- the switching command output by the control device 16 is reversed for the first specified time, and the spool 22 is reciprocated from the fully closed position. That is, the control device 16 outputs an ON signal (see reference numeral G1 in FIG. 4) from the state of outputting the OFF signal for the first specified time, and reciprocates the spool 22 from the fully closed position.
- the control device 16 may continuously output the ON signal, reverse the signal to the OFF signal for the first specified time, and reciprocate the spool 22 from the fully open position.
- step S4 which is an electrical failure determination step, the control device 16 determines whether or not there is an electrical failure in the safety lock valve 14 based on the switching command output from the control device 16. That is, the control device 16 detects the actual current (or actual voltage) for the switching command output in step S3, and compares the switching command with the actual current (or actual voltage). In the control device 16, these are completely different (in this embodiment, the actual current (or actual voltage) is zero or near zero with respect to the ON signal, or the actual current (or actual voltage) is other than zero with respect to the OFF signal. Whether or not it is determined. If they are completely different, it is determined that there is an electrical failure such as a disconnection or short circuit between the control device 16 and the safety lock valve 14.
- step S11 which is a warning stop step
- the control device 16 warns that there is an electrical failure by a warning device (for example, LED, display, etc.) (not shown), and sets the switching command as an OFF signal. Then, the self-cleaning process is completed. On the other hand, if they are the same, it is determined that there is no electrical failure, and the process proceeds to step S5.
- a warning device for example, LED, display, etc.
- step S5 which is a mechanical failure determination step
- the control device 16 determines whether or not there is a mechanical failure in the safety lock valve 14 based on the switching command output from the control device 16 and the pressure signal from the first pressure sensor 19. judge.
- the control device 16 detects the pressure output from the safety lock valve 14 based on the pressure signal from the pressure sensor 19, and determines the presence or absence of a mechanical failure based on the detected pressure and the switching command. .. That is, when the detected pressure is equal to or higher than the predetermined pressure even though the OFF signal is output, the control device 16 has a mechanical failure such as the spool 22 of the safety lock valve 14 sticking. judge.
- step S11 which is a warning stop step
- the control device 16 warns that there is a mechanical failure by a warning device (for example, LED, display, etc.) (not shown). Further, the control device 16 maintains the decompression command output to the electromagnetic proportional pressure reducing valves 15L and 15R to zero so that the spool 12a of the multi-control valve 12 does not move undesirably. Then, the self-cleaning process is completed.
- the pressure detected by the control device 16 corresponds to the switching command, it is determined that there is no mechanical failure, and the process proceeds to step S6.
- step S6 which is a cleaning end determination step, it is determined whether or not the control device 16 ends the cleaning work on the safety lock valve 14. More specifically, the control device 16 determines whether or not the first termination condition is satisfied.
- the first termination condition is, for example, that the spool 22 is reciprocated a predetermined number of times (that is, the ON signal and the OFF signal are switched a predetermined number of times), or a predetermined time has elapsed since the reciprocating motion of the spool 22 was started. In this embodiment, it is once. If it is determined that the first end condition is not satisfied, the process returns to step S3, and cleaning is continued. On the other hand, if it is determined that the first termination condition is satisfied, the cleaning of the safety lock valve 14 is completed. When completed, the process proceeds to step S7 for cleaning the electromagnetic proportional pressure reducing valves 15L and 15R.
- step S7 which is the lock state switching step
- the control device 16 shuts off the pilot passage 18. That is, the control device 16 outputs an OFF signal to move the spool 22 of the safety lock valve 14 to the shutoff position.
- the second condition of shutting off the pilot passage 18 is satisfied, and the process proceeds to step S8.
- step S8 which is the second cleaning step, the control device 16 outputs a specific decompression command to each of the electromagnetic proportional pressure reducing valves 15L and 15R to reciprocate the spool 32 from the fully closed position.
- the control device 16 reciprocates the spool 32 from the fully closed position by changing to a specific decompression command, for example, a step-like signal while the output of the zero signal is continuous.
- a specific decompression command for example, a step-like signal while the output of the zero signal is continuous.
- step S9 which is an electrical failure determination step, the control device 16 determines whether or not there is an electrical failure in the electromagnetic proportional pressure reducing valves 15L and 15R based on the pressure reducing command output from the control device 16. That is, the control device 16 detects the actual current (or actual voltage) with respect to the decompression command output in step S7 as in step 4, and calculates the deviation between the decompression command and the actual current (or actual voltage). , Determine whether the calculated deviation is within a predetermined range. If the deviation is not within the predetermined range, it is determined that there is an electrical failure such as a disconnection or a short circuit between the control device 16 and the electromagnetic proportional pressure reducing valves 15L and 15R.
- an electrical failure such as a disconnection or a short circuit between the control device 16 and the electromagnetic proportional pressure reducing valves 15L and 15R.
- step S12 which is a warning stop step
- the control device 16 warns that there is an electrical failure by a warning device (for example, LED, display, etc.) (not shown), and sets the decompression command to zero. Then, the self-cleaning process is completed.
- a warning device for example, LED, display, etc.
- step S10 which is a cleaning end determination step, it is determined whether or not the control device 16 ends the cleaning work in the electromagnetic proportional pressure reducing valves 15L and 15R. That is, the control device 16 determines whether or not the second termination condition is satisfied.
- the second end condition is, for example, reciprocating the spool 32 a predetermined number of times (that is, at least once) (that is, repeating on and off a predetermined number of times in a stepped decompression command), or starting the reciprocating motion of the spool 32. A predetermined time has passed since then. If it is determined that the second end condition is not satisfied, the process returns to step S8, and cleaning is continued. On the other hand, if it is determined that the second end condition is satisfied, the control device 16 ends the cleaning. As a result, the self-cleaning process is completed.
- the hydraulic system 1 configured in this way reverses the switching signal output in the self-cleaning process for the first specified time (or outputs a specific decompression signal), and spools 22 (or the spool 22) of the safety lock valve 14.
- the spools 32) of the electromagnetic proportional pressure reducing valves 15L and 15R are reciprocated from the fully closed position. Therefore, since a step-like switching signal (or decompression signal) can be output to generate a larger exciting force, the spool 22 (or spool 32) can be moved even if contamination is slightly bitten. Thereby, a higher cleaning effect can be achieved.
- the switching signal and the decompression signal are preferably signals that change in steps, but are not necessarily so, and may be sweep-like signals that gradually increase and decrease, and reciprocating motion. Any signal that can be made is sufficient.
- the spool 22 of the safety lock valve 14 is cleaned while the spool 12a of the multi-control valve 12 is maintained at the neutral position M, and the pilot passage 18 is shut off to perform electromagnetic proportional depressurization. Cleaning work of valves 15L and 15R is performed. Therefore, during cleaning and during determination when an electrical failure or a mechanical failure has occurred, hydraulic oil unintentionally flows into the hydraulic cylinder 2 and the hydraulic cylinder 2 moves undesirably. Can be suppressed. In the hydraulic system 1, the same effect can be obtained by stopping the driving of the engine E, that is, stopping the driving of the pilot pump 13.
- the flood control system 1A of the second embodiment has the same configuration as the flood control system 1 of the first embodiment.
- the self-cleaning process performed by the hydraulic system 1A is slightly different from the self-cleaning performed by the hydraulic system 1.
- the self-cleaning process executed by the hydraulic system 1A will be mainly described as being different from the self-cleaning process executed by the hydraulic system 1.
- the configuration of the hydraulic system 1A of the second embodiment is designated by the same reference numerals as the configuration of the hydraulic system 1 of the first embodiment, and the description thereof will be omitted.
- step S21 which is the second cleaning step
- the control device 16 outputs a specific decompression command to each of the electromagnetic proportional pressure reducing valves 15L and 15R to reciprocate the spool 32 from the fully closed position. That is, the control device 16 reciprocates the spool 32 from the fully closed position by changing the PWM signal into a specific decompression signal, for example, a step-like signal or a sweep-like signal, while the output of the zero signal is continuous.
- the control device 16 simultaneously outputs a pressure reducing command of the same or substantially the same current (or voltage) to the electromagnetic proportional pressure reducing valves 15L and 15R, respectively.
- pilot pressures PL and PR of the same pressure or substantially the same pressure can be output from the electromagnetic proportional pressure reducing valves 15L and 15R, and the spool 12a of the multi-control valve 12 is maintained at the neutral position M.
- the spools 32 of the two electromagnetic proportional pressure reducing valves 15L and 15R can be reciprocated (that is, cleaned) from the fully closed position. When the spool 32 is cleaned in this way, the process proceeds to step S9. Further, if it is determined in step S9 that there is no electrical failure, the process proceeds to step S13.
- step S13 which is a mechanical failure determination step
- the electromagnetic proportional pressure reducing valves 15L and 15R are mechanically based on the pressure reducing command output from the control device 16 and the pressure signals from the second and third pressure sensors 19L and 19R.
- the control device 16 determines whether or not there is a failure. For example, the control device 16 detects the first pilot pressure PL based on the pressure signal from the second pressure sensor 19L, and determines the presence or absence of a mechanical failure based on the detected first pilot pressure PL and the decompression command. judge. That is, when the pilot pressures PL and PR corresponding to the depressurization command are not detected, it is determined that the electromagnetic proportional pressure reducing valves 15L and 15R have a mechanical failure.
- step S11 which is a warning stop step
- the control device 16 warns that there is a mechanical failure by a warning device (for example, LED, display, etc.) (not shown). Further, the control device 16 controls the movements of the electromagnetic proportional pressure reducing valves 15L and 15R as follows so that the spool 12a of the multi-control valve 12 does not move undesirably.
- the control device 16 has the same pilot pressures PL, PR as the pilot pressures PR, PL output from the electromagnetic proportional pressure reducing valves 15R, 15L of the one having a mechanical failure, and the one having no mechanical failure.
- a decompression command is set and output so that the output is output from the electromagnetic proportional pressure reducing valves 15L and 15R of.
- the spool 12a of the multi-control valve 12 can be returned to the neutral position M and maintained, and the hydraulic cylinder 2 can be prevented from moving undesirably.
- the self-cleaning process is completed.
- the control device 16 detects the pilot pressures PL and PR corresponding to the decompression command, it is determined that there is no mechanical failure, and the process proceeds to step S10.
- the pair of electromagnetic proportional pressure reducing valves 15L and 15R can be cleaned without moving the spool 12a of the multi-control valve 12. That is, the electromagnetic proportional pressure reducing valves 15L and 15R can be cleaned without shutting off the pilot passage 18, and the step of shutting off the pilot passage 18 can be omitted.
- the flood control system 1A can exert the same effects as the flood control system 1 of the first embodiment.
- the solenoid valves are the safety lock valve 14 and the solenoid proportional pressure reducing valves 15L and 15R, but are not limited thereto.
- the solenoid valve may be a solenoid relief valve, and if the valve is configured to move the spool by a solenoid, a self-cleaning process can be performed.
- the electrical and mechanical failures of the solenoid valves 14, 15L and 15R are determined at the same time as the cleaning work, but they are performed separately from the cleaning work. A failure may be determined.
- the control device 16 may output a low current switching command and a depressurization command so that the spools 22 and 32 do not move.
- the safety lock valves 14 in the hydraulic systems 1 and 1A of the first and second embodiments do not necessarily have to be all controlled by the control device 16. That is, it may be configured to be directly operable by a switch or a safety lever.
- the safety lock valve 14 cannot be cleaned, but the same pilot pressures PL and PR are output from the two electromagnetic proportional pressure reducing valves 15L and 15R as in the hydraulic system 1A of the second embodiment. Thereby, the two electromagnetic proportional pressure reducing valves 15L and 15R can be cleaned. Further, by confirming that the pilot passage 18 is blocked by the safety lock valve 14 by the pressure detected by the pressure sensor 19, the control device 16 uses the same method as that of the hydraulic system 1 of the first embodiment. Cleaning of the two electromagnetic proportional pressure reducing valves 15L and 15R can be performed.
- the power switch and the like are turned on and the self-cleaning process is executed immediately after the engine E is started, but the self-cleaning process is not necessarily performed based on such conditions.
- the cleaning process does not have to be performed.
- the self-cleaning process may be executed when the start condition is satisfied after a while after the start, not immediately after the power switch or the like is turned on or immediately after the engine E is started. In this case, after the self-cleaning process is executed, the process proceeds to step S2 instead of step S1. Further, the self-cleaning process may be executed on condition that the power switch or the like is turned off, and if it is satisfied.
- control device 16 may be supplied with electric power periodically or by remote control so that the self-cleaning process is executed.
- the cleaning work for the spool 22 of the safety lock valve 14 is performed before the cleaning work for the spools 32 of the electromagnetic proportional pressure reducing valves 15L and 15R, but the order is not necessarily limited to that. That is, in the self-cleaning process, the cleaning work on the spools 32 of the electromagnetic proportional pressure reducing valves 15L and 15R may be performed before the cleaning work on the spool 22 of the safety lock valve 14.
- step S21 the same decompression command is output to the electromagnetic proportional pressure reducing valves 15L and 15R, respectively, but such a specific depressurizing command is not necessarily output. There is no need. That is, even if a specific depressurization command is output to the electromagnetic proportional pressure reducing valves 15L and 15R so that the secondary pressure of each of the spools 12a of the multi-control valve 12 does not operate is less than a predetermined pressure value. Good. As a result, the spools 32 of the electromagnetic proportional pressure reducing valves 15L and 15R can be reciprocated from the closed position without moving the spool 12a of the multi-control valve 12.
- the same effect as that of the hydraulic system 1A of the second embodiment can be obtained.
- the secondary pressure of the spool 12a of the multi-control valve 12 does not operate with respect to the electromagnetic proportional pressure reducing valves 15L and 15R, and the secondary pressures are less than the predetermined pressure values.
- Such a specific decompression command may be output.
- the spool 22 of the safety lock valve 14 can be reciprocated without moving the spool 12a of the multi-control valve 12, and it is possible to prevent the spool 12a from making an undesired movement during the reciprocating motion.
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Abstract
Description
産業車両及び建設車両等を含む車両や産業機械や建設機械等を含む機械(以下、単に「車両等」という)は、油圧アクチュエータ(例えば、油圧シリンダ及び油圧モータ等)2を備えており、それを動かすことによって様々な動作を行うことができる。このような車両等は、油圧アクチュエータ2に作動油を供給してそれを動かすべく油圧システム1を備えており、本実施形態の油圧システム1は、例えば油圧ショベルに備わっている。油圧システム1は、例えば油圧ショベルに備わる複動式の油圧シリンダ2に作動油を供給する。なお、油圧システム1が適用される車両は、油圧ショベルに限定されず、油圧アクチュエータ2もまた複動式の油圧シリンダ2それに限定されない。油圧アクチュエータ2は、単動式の油圧シリンダや油圧モータであってもよい。以下では、油圧システム1について説明する。
このように構成されている油圧システム1は、以下のようなセルフクリーニング機能を有している。即ち、油圧システム1は、安全ロック弁14、及び電磁比例減圧弁15L,15R等の電磁弁において各々のスプール22,32とハウジング21との間に入り込んだり、ノッチ22b,22c,32b,32c(メータリング部)等の開口部分に挟まったりしているコンタミを除去できる。このようなセルフクリーニング機能は、例えば安全ロック弁14において、それまで継続して入力されているON信号又はOFF信号を、第1規定時間(例えば、0.2sec以下の短時間)だけOFF信号又はON信号に逆転させ、スプール22を往復運動させる。これにより、スプール22を全開位置から全閉位置又は全閉位置から全開位置まで往復運動させることができる。このように往復運動させることによって、前述するコンタミを連通路22aに掻き出すことができる等、スプール22の外周面に付着するより多くのコンタミを積極的に除去することができる。これにより、コンタミに起因してスプール22がスティックしたり、ノッチ22b,22cが閉じなくなったりすること、即ち動作不良が発生することを抑制できる。また、スプール22を往復運動させることによってスプール22の外周面に作動油を馴染ませることができる。即ち、より広範囲にわたってパイロット油を馴染ませることができ、スプール22の潤滑性を高めることができる。これにより、安全ロック弁14の応答性の低下を抑制できる。なお、本実施形態では、制御装置16がスプール22を1回だけ往復運動させるが、2回以上往復運動させてもよく、少なくとも1回以上の往復運動をさせればよい。
第2実施形態の油圧システム1Aは、図1に示すように第1実施形態の油圧システム1と同じ構成を有している。他方、油圧システム1Aが実行するセルフクリーニング処理は、油圧システム1が実行するセルフクリーニングと若干異なっている。以下では、油圧システム1Aが実行するセルフクリーニング処理について、油圧システム1が実行するセルフクリーニング処理と異なる点について主に説明する。なお、第2実施形態の油圧システム1Aの構成については、第1実施形態の油圧システム1の構成と同一の符号を付してその説明を省略する。
第1及び第2実施形態の油圧システム1,1Aでは、電磁弁が安全ロック弁14及び電磁比例減圧弁15L,15Rであるが、それに限定されない。例えば、電磁弁は電磁リリーフ弁であってもよく、ソレノイドによってスプールを動かすように構成されている弁であれば、セルフクリーニング処理を実行できる。
2 油圧シリンダ(油圧アクチュエータ)
12 マルチコントロール弁(制御弁)
12a スプール(制御スプール)
13 パイロットポンプ
14 安全ロック弁(電磁弁、切換弁)
15L 第1電磁比例減圧弁(電磁弁)
15R 第2電磁比例減圧弁(電磁弁)
16 制御装置
18 パイロット通路
19,19L,19R 圧力センサ
21 ハウジング(第1ハウジング)
22 スプール(第1弁スプール)
31 ハウジング(第2ハウジング)
32 スプール(第2弁スプール)
Claims (15)
- ハウジング内を摺動する弁スプールを有し、入力される作動指令に応じて前記弁スプールを移動させる電磁弁と、
前記電磁弁に作動指令を出力する制御装置とを備え、
前記制御装置は、所定の条件を充足すると、全開位置又は全閉位置から前記弁スプールを往復運動させるべく作動指令を前記電磁弁に与える、油圧システム。 - 前記電磁弁は、電磁切換弁であって、
作動指令は、前記弁スプールを全開位置に位置させる開指令と、前記弁スプールを全閉位置に位置させる閉指令を含み、
前記制御装置は、前記条件を充足すると、前記電磁切換弁に継続して与えられる開指令及び閉指令の何れか一方の作動指令を短い規定時間だけ他方の作動指令に逆転させて前記弁スプールを往復運動させる、請求項1に記載の油圧システム。 - 前記電磁弁は、電磁比例減圧弁であって、
作動指令は、前記弁スプールを前記全開位置又は前記全閉位置に位置させる所定指令を含み、
前記制御装置は、前記条件を充足すると、継続して前記電磁比例減圧弁に与えられる前記所定指令を規定時間の間、特定の作動指令に変えて前記弁スプールを往復運動させる、請求項1に記載の油圧システム。 - 一対の前記電磁弁を備え、
前記一対の電磁弁の各々は、電磁比例減圧弁であって、各々から出力される二次圧を制御弁の制御スプールに対して互いに抗する方向に作用させるように配置され、
作動指令は、前記弁スプールを前記全開位置又は前記全閉位置に位置させる所定指令を含み、
前記制御装置は、前記条件を充足すると、継続して前記電磁比例減圧弁に与えられる前記所定指令を規定時間の間、特定の作動指令に変えて、前記一対の電磁比例減圧弁の各々の二次圧を同一にし且つ前記弁スプールを往復運動させる、請求項1に記載の油圧システム。 - 前記電磁比例減圧弁の上流側に設けられ、前記電磁弁への作動油の流れを遮断可能な切換弁を備え、
前記条件は、前記切換弁によって前記電磁弁への作動油の流れが遮断されていることを含む、請求項3又は4に記載の油圧システム。 - 前記電磁弁は、電磁比例減圧弁であって、前記電磁比例減圧弁から出力される二次圧を制御弁の制御スプールに作用させるように配置され、
前記制御弁は、二次圧が所定値未満では作動しない不感帯を有し、
前記制御装置は、前記弁スプールを往復運動させる際の作動指令を前記電磁比例減圧弁から出力される二次圧が所定値未満となるようにする、請求項1、3、及び4の何れか1つに記載の油圧システム。 - 前記制御装置は、ステップ状の作動指令を前記電磁比例減圧弁に出力することによって前記弁スプールを往復運動させる、請求項3乃至6の何れか1つに記載の油圧システム。
- 前記条件は、前記電磁弁の下流側に油圧が流れない状態であることを含む、請求項1乃至7の何れか1つに記載の油圧システム。
- 前記電磁弁の下流側に設けられる圧力センサを更に備え、
前記制御装置は、前記圧力センサによって検出される圧力と前記電磁弁に出力する作動指令とに基づいて前記弁スプールの動作不良を検知する、請求項1乃至3の何れか1つに記載の油圧システム。 - パイロット油を吐出するパイロットポンプと、
パイロット通路を介して前記パイロットポンプに接続され、入力される減圧指令に応じた二次圧を出力する電磁比例減圧弁と、
前記電磁比例減圧弁から出力される二次圧に応じて、油圧アクチュエータに流す圧油の流れを制御する制御弁と、
前記パイロット通路に介在し、入力される切換指令に応じて前記パイロット通路を遮断する電磁切換弁と、
前記電磁比例減圧弁に減圧指令を出力し、且つ前記電磁切換弁に切換指令を出力する制御装置と、を備え、
前記電磁切換弁は、第1ハウジング内を摺動する第1弁スプールを有し、入力される切換指令に応じて前記第1弁スプールを移動させることによって前記パイロット通路の遮断し、
前記電磁比例減圧弁は、第2ハウジング内を摺動する第2弁スプールを有し、入力される減圧指令に応じて前記第2弁スプールを移動させることによって出力する二次圧を調整し、
前記制御装置は、所定の第1条件を充足すると、全開位置又は全閉位置から前記第1弁スプールを往復運動させるべく切換指令を前記電磁切換弁に与え、所定の第2条件を充足すると、全開位置又は全閉位置から前記第2弁スプールを往復運動させるべく減圧指令を前記電磁比例減圧弁に与える、油圧システム。 - 切換指令は、前記第1弁スプールを全開位置に位置させる開指令と、前記第1弁スプールを全閉位置に位置させる閉指令を含み、
減圧指令は、前記第2弁スプールを前記全開位置又は前記全閉位置に位置させる所定指令を含み、
前記制御装置は、前記第1条件を充足すると、前記電磁切換弁に継続して与えられる開指令及び閉指令の何れか一方の作動指令を短い第1規定時間だけ他方の作動指令に逆転させて前記第1弁スプールを往復運動させ、前記第2条件を充足すると、継続して前記電磁比例減圧弁に与えられる前記所定指令を第2規定時間の間、特定の作動指令に変えて前記第2弁スプールを往復運動させる、請求項10に記載の油圧システム。 - 一対の前記電磁比例減圧弁を備え、
前記制御弁は、制御スプールを有し、前記制御スプールの位置に応じて前記油圧アクチュエータに流す圧油の流れを制御し、
前記一対の電磁比例減圧弁の各々は、各々から出力される二次圧を前記制御スプールに対して互いに抗する方向に作用させて前記制御スプールを動かし、
切換指令は、前記第1弁スプールを全開位置に位置させる開指令と、前記第1弁スプールを全閉位置に位置させる閉指令を含み、
減圧指令は、前記第2弁スプールを全開位置又は全閉位置に位置させる所定指令を含み、
前記制御装置は、前記第1条件を充足すると、前記電磁切換弁に継続して与えられる開指令及び閉指令の何れか一方の作動指令を短い第1規定時間だけ他方の作動指令に逆転させて前記第1弁スプールを往復運動させ、前記第2条件を充足すると、継続して前記電磁比例減圧弁に与えられる前記所定指令を第2規定時間の間、特定の減圧指令に変えて前記一対の電磁比例減圧弁の各々の二次圧を同一にし且つ前記第2弁スプールを往復運動させる、請求項10に記載の油圧システム。 - 前記制御弁は、二次圧が所定値未満では作動しない不感帯を有し、
前記第1条件には、前記電磁比例減圧弁から出力される二次圧が所定値未満となるような減圧指令が出力されていることを含む、請求項10乃至12の何れか1つに記載の油圧システム。 - 前記第2条件には、前記電磁切換弁によって前記パイロット通路が遮断されていることを含む、請求項10又は11に記載の油圧システム。
- 前記第1条件及び前記第2条件の少なくとも一方には、前記パイロットポンプが停止していることを含む、請求項10乃至14の何れか1つに記載の油圧システム。
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