EP3379090A1 - Counter balance valve and fluid pressure control device provided with counter balance valve - Google Patents

Counter balance valve and fluid pressure control device provided with counter balance valve Download PDF

Info

Publication number
EP3379090A1
EP3379090A1 EP16865999.3A EP16865999A EP3379090A1 EP 3379090 A1 EP3379090 A1 EP 3379090A1 EP 16865999 A EP16865999 A EP 16865999A EP 3379090 A1 EP3379090 A1 EP 3379090A1
Authority
EP
European Patent Office
Prior art keywords
control valve
flow rate
valve
fluid pressure
motor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP16865999.3A
Other languages
German (de)
English (en)
French (fr)
Inventor
Tatsuo Ito
Junichiro Sugimoto
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
KYB Corp
Original Assignee
KYB Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by KYB Corp filed Critical KYB Corp
Publication of EP3379090A1 publication Critical patent/EP3379090A1/en
Withdrawn legal-status Critical Current

Links

Images

Classifications

    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/2058—Electric or electro-mechanical or mechanical control devices of vehicle sub-units
    • E02F9/2083—Control of vehicle braking systems
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/2221—Control of flow rate; Load sensing arrangements
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/2221—Control of flow rate; Load sensing arrangements
    • E02F9/2225—Control of flow rate; Load sensing arrangements using pressure-compensating valves
    • E02F9/2228—Control of flow rate; Load sensing arrangements using pressure-compensating valves including an electronic controller
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/2253—Controlling the travelling speed of vehicles, e.g. adjusting travelling speed according to implement loads, control of hydrostatic transmission
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/226—Safety arrangements, e.g. hydraulic driven fans, preventing cavitation, leakage, overheating
    • 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
    • F15B11/02—Systems essentially incorporating special features for controlling the speed or actuating force of an output member
    • F15B11/04—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed
    • F15B11/0406—Systems essentially incorporating special features for controlling the speed or actuating force of an output member for controlling the speed during starting or stopping
    • 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
    • F15B13/029—Counterbalance valves
    • 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
    • F15B13/0401—Valve members; Fluid interconnections therefor
    • 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
    • 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
    • F15B21/00—Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
    • F15B21/08—Servomotor systems incorporating electrically operated control means
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/2264—Arrangements or adaptations of elements for hydraulic drives
    • E02F9/2267—Valves or distributors
    • 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
    • F15B13/0401—Valve members; Fluid interconnections therefor
    • F15B2013/0412—Valve members; Fluid interconnections therefor with three positions
    • 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
    • F15B2211/40—Flow control
    • F15B2211/405—Flow control characterised by the type of flow control means or valve
    • F15B2211/40515—Flow control characterised by the type of flow control means or valve with variable throttles or orifices
    • 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
    • F15B2211/40—Flow control
    • F15B2211/42—Flow control characterised by the type of actuation
    • F15B2211/426—Flow control characterised by the type of actuation electrically or electronically
    • 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
    • F15B2211/632—Electronic controllers using input signals representing a flow rate
    • F15B2211/6326—Electronic controllers using input signals representing a flow rate the flow rate being an output member flow rate
    • 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
    • F15B2211/6336—Electronic controllers using input signals representing a state of the output member, e.g. position, speed or acceleration
    • 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
    • F15B2211/634—Electronic controllers using input signals representing a state of a valve
    • 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
    • F15B2211/6346—Electronic controllers using input signals representing a state of input means, e.g. joystick position
    • 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
    • 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
    • F15B2211/67—Methods for controlling pilot pressure
    • 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
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/705—Output members, e.g. hydraulic motors or cylinders or control therefor characterised by the type of output members or actuators
    • F15B2211/7058—Rotary output members
    • 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
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/715—Output members, e.g. hydraulic motors or cylinders or control therefor having braking means
    • 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
    • F15B2211/70—Output members, e.g. hydraulic motors or cylinders or control therefor
    • F15B2211/755—Control of acceleration or deceleration of the output member

Definitions

  • the present invention relates to a counterbalance valve and a fluid pressure control device including a counterbalance valve.
  • JP06-147201A describes a drive circuit of a hydraulic motor constituting a traveling device of a construction machine, in which the drive circuit interposes a counterbalance valve between the hydraulic motor and a directional control valve to suppress the impact occurring at the time of starting and stopping.
  • a counterbalance valve In the counterbalance valve described in JP06-147201A , an orifice is provided in a passage that allows an oil chamber defined on both ends of a plunger to communicate with a hydraulic passage communicating to the hydraulic motor.
  • a stroke speed of the plunger of the counterbalance valve is determined depending on the diameter of the orifice. More specifically, with a larger orifice diameter, the stroke speed of the plunger increases, and with a smaller orifice diameter, the stroke speed of the plunger slows down.
  • the orifice diameter is set on the basis that the construction machine will travel on flat surface.
  • the distance until the construction machine stops would extend when attempting to stop while traveling on a downslope.
  • the orifice diameter is set on the basis of traveling on the downslope, the construction machine would suddenly stop when attempting to stop while traveling on flat surface.
  • An object of the present invention is to provide a counterbalance valve that can appropriately adjust a braking distance of a vehicle body, and a fluid pressure control device comprising this counterbalance valve.
  • a counterbalance valve includes: a valve-side passage communicating with the directional control valve; a motor-side passage communicating with the fluid pressure motor; a control valve configured to control flowing of working fluid between the valve-side passage and the motor-side passage when the directional control valve is switched; a pilot chamber to which pilot pressure for controlling the control valve is guided; a pilot passage communicating the valve-side passage with the pilot chamber; and a flow rate control valve configured to variably control a flow rate of working fluid flowing through the pilot passage.
  • Fig. 1 is a hydraulic circuit diagram showing the counterbalance valve 10 and the fluid pressure control device 100 including the counterbalance valve 10, in the first embodiment.
  • the fluid pressure control device 100 is mounted in a vehicle body of a working machine that is driven by fluid pressure, such as a power shovel or a wheel loader.
  • fluid pressure such as a power shovel or a wheel loader.
  • working oil is used as the working fluid
  • other fluids such as working water may be used as the working fluid.
  • the fluid pressure control device 100 includes a pump 1 that discharges working oil, a hydraulic motor 2 as a fluid pressure motor driven by the working oil discharged from the pump 1, a directional control valve 3 provided in a flow passage connecting the pump 1 with the hydraulic motor 2 and which switches a rotating direction of the hydraulic motor 2, a supply flow passage 21 connecting the pump 1 with the directional control valve 3, supply and discharge flow passages 22a and 22b connecting the hydraulic motor 2 with the directional control valve 3, and a remote control valve 5 that controls pilot pressure of the directional control valve 3.
  • the pump 1 is driven by power of an engine not shown, and discharges working oil to the supply flow passage 21.
  • the pump 1 is a swash plate axial piston pump.
  • the pump 1 is shown as a fixed displacement type in Fig. 1 , it is not limited to this and may be a variable displacement type.
  • the hydraulic motor 2 is a swash plate axial piston motor with a fixed displacement, and is used as a hydraulic motor for traveling.
  • the hydraulic motor 2 is rotatably driven upon receiving supply of the working oil discharged from the pump 1.
  • the hydraulic motor 2 switches between forward rotation and reverse rotation caused by the directional control valve 3. With the forward rotation of the hydraulic motor 2, the working machine moves forward, and with the reverse rotation of the hydraulic motor 2, the working machine moves backward.
  • the hydraulic motor 2 is not limited to the swash plate axial piston motor of the fixed displacement, and may be a swash plate axial piston motor of a variable displacement.
  • the hydraulic motor 2 is provided with a negative type parking brake 2a that applies braking force to the hydraulic motor 2 when stopping.
  • the parking brake 2a is connected to a counterbalance valve 10 described later, via a flow passage 23.
  • the parking brake 2a allows the hydraulic motor 2 to rotate upon releasing the brake when the pressure of the flow passage 23 exceeds a predetermined pressure (brake release pressure).
  • the directional control valve 3 includes a forward position A that guides the working oil discharged from the pump 1 into the supply flow passage 21 to the hydraulic motor 2 through the supply and discharge flow passage 22a, a backward position B that guides the working oil discharged from the pump 1 into the supply flow passage 21 to the hydraulic motor 2 through the supply and discharge flow passage 22b, and a neutral position C that allows the pump 1 and the hydraulic motor 2 to communicate with a tank T.
  • the directional control valve 3 is switched due to working oil (pilot pressure) supplied from a pilot pump 4 to pilot chambers 3a and 3b through a remote control valve 5 in association with an operator of the working machine manipulating the remote control valve 5.
  • the directional control valve 3 switches to the forward position A, and when the remote control valve 5 is manipulated to the other side and the pilot pressure is supplied to the pilot chamber 3b, the directional control valve 3 switches to the backward position B.
  • the remote control valve 5 is in a neutral position, that is, when no pilot pressure is acting on either of the pilot chambers 3a and 3b, the directional control valve 3 becomes in the neutral position C due to an energizing force of springs 3c provided on both sides of the directional control valve 3.
  • the pilot pressure supplied to the pilot chambers 3a and 3b is controlled in accordance with the manipulated amount of the remote control valve 5.
  • the remote control valve 5 includes a position detecting sensor 5a that detects a neutral state of the remote control valve 5.
  • the position detecting sensor 5a outputs a detection signal to a controller 40 when the operation lever of the remote control valve 5 is in the neutral position.
  • the directional control valve 3 is also in the neutral state. Namely, the neutral state of the directional control valve 3 can be detected by the position detecting sensor 5a.
  • the position detecting sensor 5a is equivalent to a neutral state detecting unit adapted to detect that the directional control valve 3 is in the neutral state.
  • the fluid pressure control device 100 further includes the counterbalance valve 10 provided between the directional control valve 3 and the hydraulic motor 2.
  • the counterbalance valve 10 is provided in the supply and discharge flow passages 22a and 22b.
  • the counterbalance valve 10 includes valve-side passages 14a and 14b that communicate with the directional control valve 3 through the supply and discharge flow passages 22a and 22b, motor-side passages 15a and 15b that communicate with the hydraulic motor 2 through the supply and discharge flow passages 22a and 22b, a control valve 11 that controls the flow of the working oil between the valve-side passages 14a and 14b and the motor-side passages 15a and 15b when the directional control valve 3 is switched, pilot chambers 11a and 11b to which pilot pressure to control the control valve 11 is guided, pilot passages 13a and 13b that allow the valve-side passages 14a and 14b to communicate with the pilot chambers 11a and 11b, and flow rate control valves 12a and 12b provided in the pilot passages 13a and 13b and which variably controls the flow rate of the working oil flowing through the pilot passages 13a and 13b.
  • the pilot chambers 11a and 11b are provided on either ends of the control valve 11.
  • the pilot passages 13a and 13b branch from the respective valve-side passages 14a and 14b and communicate with the pilot chambers 11a and 11b, respectively.
  • the control valve 11 includes a working position D that allows the valve-side passage 14a to communicate with the motor-side passage 15a and the flow passage 23 and allows the valve-side passage 14b to communicate with the motor-side passage 15b, a working position E that allows the valve-side passage 14a to communicate with the motor-side passage 15a and allows the valve-side passage 14b to communicate with the motor-side passage 15b and the flow passage 23, and a neutral position F that disconnects the communication between the valve-side passage 14a and 14b and the motor-side passage 15a and 15b.
  • the control valve 11 When the directional control valve 3 is switched to the forward position A, the control valve 11 is switched to the working position D by the working oil discharged from the pump 1 being guided to the pilot chamber 11a through the supply and discharge flow passage 22a, the valve-side passage 14a and the pilot passage 13a. Moreover, when the directional control valve 3 is switched to the backward position B, the control valve 11 is switched to the working position E by the working oil discharged from the pump 1 being guided to the pilot chamber 11b through the supply and discharge flow passage 22b, the valve-side passage 14b and the pilot passage 13b.
  • the control valve 11 is switched to the neutral position F by the working oil within the pilot chambers 11a and 11b being discharged to the tank T through the supply and discharge flow passages 22a and 22b, the pilot passages 13a and 13b and the valve-side passages 14a and 14b, due to the energizing force of the spring 11c provided on both sides.
  • the flow rate control valves 12a and 12b are electromagnetic proportional control valves including an electromagnetic proportional solenoid.
  • the flow rate control valves 12a and 12b control the flow rate of the working oil flowing through the pilot passages 13a and 13b, by the flow passage area varying on the basis of an electric current applied from the controller 40.
  • the flow rate control valves 12a and 12b function as a variable throttle.
  • the flow rate control valves 12a and 12b have a minimum flow passage area (throttle) in a state in which no electric current is applied from the controller 40, and is controlled to have the flow passage area (throttle) increase as the electric current applied from the controller 40 increases.
  • the flow rate control valves 12a and 12b control the pressure of the working oil within the pilot chambers 11a and 11b and adjust the switching speed of the control valve 11, by controlling the flow rate of the working oil flowing through the pilot passages 13a and 13b.
  • the fluid pressure control device 100 further includes an inclination sensor 30 as an inclination detecting unit to detect a tilt angle of a vehicle body of the working machine, and a flow rate sensor 50 as a flow rate detecting unit to detect the flow rate of the working oil flowing to the hydraulic motor 2.
  • the inclination sensor 30 detects the tilt angle in the forward-backward direction towards a horizontal plane of the vehicle body of the working machine, and outputs the detected tilt angle to the controller 40.
  • the flow rate sensor 50 is provided in the supply and discharge flow passage 22a, detects the flow rate of the working oil flowing through the supply and discharge flow passage 22a and outputs the detected flow rate to the controller 40.
  • the flow rate sensor 50 may be provided in the supply and discharge flow passage 22b.
  • First described is a case of moving the working machine forwards.
  • the working oil discharged from the pilot pump 4 is supplied to the pilot chamber 3a through the remote control valve 5.
  • the pilot chamber 3a is supplied with a pilot pressure in accordance with the manipulated amount of the remote control valve 5. This causes the directional control valve 3 to switch to the forward position A, and the working oil discharged from the pump 1 flows from the supply flow passage 21 into the valve-side passage 14a of the counterbalance valve 10 through the supply and discharge flow passage 22a.
  • the directional control valve 3 is not in the neutral state, and thus no electric current from the controller 40 is applied to the flow rate control valve 12a. Accordingly, the flow passage area of the flow rate control valve 12a is at its minimum. Therefore, since the flow is limited by the flow rate control valve 12a, the working oil flowing through the pilot passage 13a flows gently into the pilot chamber 11a. This causes the control valve 11 to gradually switch to the working position D.
  • the working oil discharged from the pump 1 is supplied to the hydraulic motor 2 through the supply flow passage 21, the directional control valve 3, the supply and discharge flow passage 22a, the valve-side passage 14a, the control valve 11, the motor-side passage 15a, and the supply and discharge flow passage 22a. Simultaneously to this, the working oil discharged from the pump 1 is supplied to the parking brake 2a via the control valve 11 through the flow passage 23, thereby releasing the parking brake 2a. This causes the hydraulic motor 2 to rotate forwardly, and the working machine moves forward.
  • the flow rate of the working oil flowing through the supply and discharge flow passage 22a is detected by the flow rate sensor 50, and the detected flow rate is outputted to the controller 40.
  • the working oil discharged from the hydraulic motor 2 is returned to the tank T through the supply and discharge flow passage 22b, the motor-side passage 15b, the control valve 11, the valve-side passage 14b, the supply and discharge flow passage 22b, and the directional control valve 3.
  • valve-side passage 14a communicates with the tank T through the supply and discharge flow passage 22a and the directional control valve 3. This causes the working oil within the pilot chamber 11a to be discharged to the tank T through the pilot passage 13a, the valve-side passage 14a, the supply and discharge flow passage 22a, and the directional control valve 3.
  • the position detecting sensor 5a provided in the remote control valve 5 detects that the operation lever of the remote control valve 5 is in the neutral state, and outputs a detection signal to the controller 40.
  • the controller 40 applies an electric current in accordance with the tilt angle detected by the inclination sensor 30, to the flow rate control valve 12a. More specifically, the controller 40 applies no electric current to the flow rate control valve 12a when the working machine is in a horizontal state, and when the working machine is in a state tilted with the front side lower, a larger electric current is applied to the flow rate control valve 12a with a larger tilt angle of the vehicle body.
  • the fluid pressure control device 100 can make the braking force to the hydraulic motor 2 occur earlier when the working machine is traveling forward on the downslope, and thus the braking distance at the time of the working machine stopping can be made shorter.
  • the controller 40 receives the flow rate of the supply and discharge flow passage 22a detected by the flow rate sensor 50.
  • the controller 40 applies an electric current to the flow rate control valve 12a in accordance with the flow rate detected by the flow rate sensor 50. More specifically, the controller 40 applies a larger electric current to the flow rate control valve 12a with a greater flow rate.
  • the flow rate detected by the flow rate sensor 50 is equal to the flow rate of the working oil supplied to the hydraulic motor 2, and thus with a greater flow rate detected at the flow rate sensor 50, a rotational speed of the hydraulic motor 2 will become faster.
  • the switching speed of the control valve 11 will increase, and thus the communication between the valve-side passage 14a and the motor-side passage 15a will be disconnected quicker than the case in which the rotational speed of the hydraulic motor 2 is slow (when the speed of the working machine is slow), and the braking force occurs quicker to the hydraulic motor 2.
  • the fluid pressure control device 100 can cause the braking force to the hydraulic motor 2 to occur quicker when the speed of the working machine is fast, and thus the braking distance of the working machine can be made short.
  • the working oil discharged from the pilot pump 4 is supplied to the pilot chamber 3b through the remote control valve 5.
  • the pilot chamber 3b is supplied with a pilot pressure in accordance with the manipulated amount of the remote control valve 5. This makes the directional control valve 3 switch to the backward position B, and the working oil discharged from the pump 1 flows from the supply flow passage 21 into the valve-side passage 14b of the counterbalance valve 10 through the supply and discharge flow passage 22b.
  • the directional control valve 3 is not in the neutral state, and thus no electric current is applied from the controller 40 to the flow rate control valve 12b. Therefore, the flow passage area of the flow rate control valve 12b is in its minimum. Therefore, the working oil flowing through the pilot passage 13b is limited in the flow by the flow rate control valve 12b, and thus the working oil flows into the pilot chamber 11b gradually. This causes the control valve 11 to switch to the working position E gradually.
  • the working oil discharged from the pump 1 is supplied to the hydraulic motor 2 through the supply flow passage 21, the directional control valve 3, the supply and discharge flow passage 22b, the valve-side passage 14b, the control valve 11, the motor-side passage 15b, and the supply and discharge flow passage 22b. Simultaneously to this, the working oil discharged from the pump 1 is supplied to the parking brake 2a from the control valve 11 through the flow passage 23, and the parking brake 2a is released. This causes the hydraulic motor 2 to rotate backwards, and the working machine moves backwards.
  • the working oil discharged from the hydraulic motor 2 is returned to the tank T through the supply and discharge flow passage 22a, the motor-side passage 15a, the control valve 11, the valve-side passage 14a, the supply and discharge flow passage 22a, and the directional control valve 3.
  • the flow rate of the working oil flowing through the supply and discharge flow passage 22a is detected by the flow rate sensor 50, and the detected flow rate is outputted to the controller 40.
  • valve-side passage 14b communicates with the tank T through the supply and discharge flow passage 22b and the directional control valve 3. This causes the working oil within the pilot chamber 11b to be discharged to the tank T through the pilot passage 13b, the valve-side passage 14b, the supply and discharge flow passage 22b, and the directional control valve 3.
  • the position detecting sensor 5a provided in the remote control valve 5 detects that the operation lever of the remote control valve 5 is in the neutral position, and outputs a detection signal to the controller 40.
  • the controller 40 applies an electric current in accordance with a tilt angle detected by the inclination sensor 30, to the flow rate control valve 12b. More specifically, when the working machine is in the horizontal state, the controller 40 applies no electric current to the flow rate control valve 12b, and when the working machine is in a tilted state with its rear side lower, the controller 40 applies a greater electric current to the flow rate control valve 12b with a larger tilt angle of the vehicle body.
  • the fluid pressure control device 100 can cause the braking force on the hydraulic motor 2 to occur earlier, and thus can shorten the braking distance at the time of stopping the working machine.
  • the controller 40 receives the flow rate of the supply and discharge flow passage 22a that is detected by the flow rate sensor 50.
  • the controller 40 applies an electric current in accordance with the flow rate detected by the flow rate sensor 50 to the flow rate control valve 12b. More specifically, the controller 40 applies a greater electric current to the flow rate control valve 12b with a greater flow rate.
  • the flow rate detected by the flow rate sensor 50 is equal to the flow rate of the working oil supplied to the hydraulic motor 2, and thus when the flow rate detected at the flow rate sensor 50 is great, the rotational speed of the hydraulic motor 2 will be fast.
  • the switching speed of the control valve 11 increases; thus, the communication between the valve-side passage 14b and the motor-side passage 15b is disconnected earlier than when the rotational speed of the hydraulic motor 2 is slow (when the speed of the working machine is slow), and the braking force in the hydraulic motor 2 occurs earlier.
  • the fluid pressure control device 100 can cause the braking force on the hydraulic motor 2 to occur earlier when the speed of the working machine is fast, and thus can shorten the braking distance of the working machine.
  • the flow rate control valves 12a and 12b are described using examples of electromagnetic proportional control valves, this may be a two-position electromagnetic switching valve.
  • a threshold value may be provided to the tilt angle detected by the inclination sensor 30 and the flow rate detected by the flow rate sensor 50, and make the position of the electromagnetic switching valve to switch their positions when the threshold value is exceeded. This requires just the ON/OFF controlling of the positions of the flow rate control valves 12a and 12b, and thus allows for facilitating the controlling by the controller 40.
  • the flow rate control valves 12a and 12b may be rotary valves 60a and 60b driven by an electric motor, as shown in Fig. 2 .
  • an electric motor such as a stepping motor is employed, however an electric motor of any form may be used as long as the rotation angle can be detected.
  • the flow rate control valves 12a and 12b may be provided with a stroke sensor 12c that detects a stroke of a valve body of the flow rate control valves 12a and 12b. By controlling the stroke of the valve body detected by the stroke sensor 12c while providing feedback, control may be performed with further higher accuracy.
  • the fluid pressure control device 100 is configured that the flow rate control valves 12a and 12b are controlled by the controller 40, the flow rate control valves 12a and 12b may be of a variable throttle by manual manipulation. Even with such a configuration, the switching speed of the control valve 11 can be adjusted as appropriate.
  • the fluid pressure control device 100 may be configured to control the flow rate control valves 12a and 12b just by the tilt angle detected by the inclination sensor 30, or just by the flow rate detected by the flow rate sensor 50. Furthermore, the flow rate control valves 12a and 12b may be configured by providing just the flow rate control valve 12a being on the forward side.
  • the controller 40 may control the flow rate control valves 12a and 12b not just when the vehicle body is in the front side lowered state but also when the vehicle body is in a front side raised state.
  • a constant electric current may be applied to the flow rate control valves 12a and 12b to increase or decrease the electric current applied in accordance with the tilt angle of the vehicle body.
  • the counterbalance valve 10 includes the flow rate control valves 12a and 12b that variably control the flow rate of the working oil flowing through the pilot passages 13a and 13b. Accordingly, the flow rate of the working oil flown into/discharged from the pilot chambers 11a and 11b of the control valve 11 can be controlled to adjust the switching speed of the control valve 11. This allows for the control valve 11 to adjust a timing of disconnecting the communication between the hydraulic motor 2 and the pump 1 as appropriate, and thus allows for adjusting the braking of the hydraulic motor 2. Therefore, it is possible to adjust the braking distance of the vehicle body as appropriate.
  • the flow rate control valves 12a and 12b control the flow of the working oil discharged from the pilot chambers 11a and 11b in accordance with the tilt angle detected by the inclination sensor 30 and the flow rate detected by the flow rate sensor 50.
  • the fluid pressure control device 100 includes the position detecting sensor 5a that detects that the directional control valve 3 is in the neutral state, and the inclination sensor 30 that detects the tilt angle of the vehicle body; further, the flow rate control valves 12a and 12b are controlled in accordance with the tilt angle detected by the inclination sensor 30 when the neutral state is detected by the position detecting sensor 5a. Therefore, when the hydraulic motor 2 is to be stopped, the switching speed of the control valve 11 is adjusted in accordance with the tilt angle detected by the inclination sensor 30, to adjust the timing of disconnecting the communication between the hydraulic motor 2 and the pump 1.
  • the fluid pressure control device 100 can make the braking force on the hydraulic motor 2 occur in accordance with the tilt angle of the vehicle body by the counterbalance valve 10; thus, the braking of the vehicle body can be performed in an appropriate braking distance even when the vehicle body is tilted with its front side lower.
  • the fluid pressure control device 100 includes the flow rate sensor 50 that detects the flow rate of the working oil flowing to the hydraulic motor 2, and the flow rate control valves 12a and 12b are controlled in accordance with the flow rate detected by the flow rate sensor 50. Therefore, when stopping the hydraulic motor 2, the switching speed of the control valve 11 is adjusted in accordance with the flow rate detected by the flow rate sensor 50 to adjust the timing to disconnect the communication between the hydraulic motor 2 and the pump 1. Accordingly, the fluid pressure control device 100 can make a braking force on the hydraulic motor 2 occur in accordance with the speed of the working machine by the counterbalance valve 10; thus, the braking of the vehicle body can be performed at an appropriate braking distance even when the speed of the working machine is fast.
  • a fluid pressure control device 200 according to a second embodiment of the present invention is described with reference to Fig. 4 .
  • points different from the above first embodiment will be mainly described, and configurations identical to those in the fluid pressure control device 100 of the first embodiment will be given the same reference signs, and description thereof will be omitted.
  • the flow rate of the working oil flowing to the hydraulic motor 2 is detected by the flow rate sensor 50.
  • the second embodiment differs in the point that the flow rate of the working oil flowing to the hydraulic motor 2 is calculated by a differential pressure gauge 70 and a rotation speed sensor 80. This will be described in detail below.
  • the fluid pressure control device 200 includes the differential pressure gauge 70 as a differential pressure detecting unit that detects a differential pressure between a supply side and a discharge side in the hydraulic motor 2, and the rotation speed sensor 80 as a rotational speed detecting unit that detects a rotation speed of the hydraulic motor 2.
  • the differential pressure gauge 70 detects pressures of the supply and discharge flow passage 22a and the supply and discharge flow passage 22b, and outputs their difference to the controller 40.
  • the rotation speed sensor 80 is provided in the vicinity of a rotational shaft of the hydraulic motor 2, and detects the rotation speed of this rotational shaft and outputs the rotation speed of the hydraulic motor 2 to the controller 40.
  • a map is stored in advance which shows a relationship between the differential pressure detected by the differential pressure gauge 70 and a volume efficiency of the hydraulic motor 2.
  • the controller 40 calculates the flow rate of the hydraulic motor 2 based on the rotation speed detected by the rotation speed sensor 80, the differential pressure detected by the differential pressure gauge 70, and the above map. By the flow rate calculated as such, the flow rate control valves 12a and 12b are controlled as with the first embodiment.
  • a pressure meter may be provided on the supply side and the discharge side of the hydraulic motor 2, and the control may be performed based on a difference between pressures detected by these pressure meters.
  • the differential pressure gauge 70 and the rotation speed sensor 80 have small measurement errors as compared to the flow rate sensor 50, and thus can calculate the flow rate with good accuracy. Therefore, the flow rate control valves 12a and 12b can be controlled more accurately. This thus allows for adjusting the braking distance of the vehicle body more suitably in accordance with the rotational speed of the hydraulic motor 2.
  • the counterbalance valve 10 includes the valve-side passages 14a and 14b that communicate with the directional control valve 3, the motor-side passages 15a and 15b that communicate with the fluid pressure motor (hydraulic motor 2), the control valve 11 that controls the flow of the working oil between the valve-side passages 14a and 14b and the motor-side passages 15a and 15b when the directional control valve 3 is switched, the pilot chambers 11a and 11b to which pilot pressures for controlling the control valve 11 are guided, the pilot passages 13a and 13b that allow the valve-side passages 14a and 14b to communicate with the pilot chambers 11a and 11b, and the flow rate control valves 12a and 12b that variably control the flow rate of the working oil flowing through the pilot passages 13a and 13b.
  • the counterbalance valve 10 includes the flow rate control valves 12a and 12b that variably control the flow rate of the working oil flowing through the pilot passages 13a and 13b;Therefore, by adjusting the flow rate of the working oil flowing into/discharged from the pilot chambers 11a and 11b of the control valve 11, the switching speed of the control valve 11 can be adjusted.
  • This allows for adjusting the timing for the control valve 11 to disconnect the communication between the fluid pressure motor (hydraulic motor 2) and the pump 1, and thus can adjust the braking of the fluid pressure motor (hydraulic motor 2). Accordingly, the braking distance of the vehicle body can be suitably adjusted.
  • the flow rate control valves 12a and 12b are controlled to increase the flow passage area when the directional control valve 3 is switched from an activation position (forward position A or backward position B) of the fluid pressure motor (hydraulic motor 2) to the stop position (neutral position C) of the fluid pressure motor (hydraulic motor 2).
  • the flow passage area increases in the flow rate control valves 12a and 12b when the directional control valve 3 is switched from the activation position of the fluid pressure motor (hydraulic motor 2) (forward position A or backward position B) to the stop position of the fluid pressure motor (hydraulic motor 2).
  • This allows for quickening the timing that the control valve 11 disconnects the communication between the fluid pressure motor (hydraulic motor 2) and the pump 1, and can prevent the braking distance of the vehicle body from extending.
  • the pilot chambers 11a and 11b are provided on each of end portions of the control valve 11, and the flow rate control valves 12a and 12b are provided in respective pilot passages 13a and 13b that guide the pilot pressure to their respective pilot chambers 11a and 11b.
  • the flow rate control valves 12a and 12b are electromagnetic switching valves.
  • the flow rate control valves 12a and 12b are electromagnetic switching valves; therefore, the electric current just needs to be switched ON or OFF. This thus allows for simplifying the controlling.
  • the flow rate control valves 12a and 12b are rotary valves 60a and 60b driven by an electric motor.
  • the flow rate control valves 12a and 12b are electromagnetic proportional control valves.
  • minute control can be performed since electric motors and electromagnetic proportional control valves are used.
  • the flow rate control valves 12a and 12b further include the stroke sensor 12c that detects the moved amount of the valve body.
  • the fluid pressure control device 100 includes the pump 1 that discharges working oil, the fluid pressure motor (hydraulic motor 2) that drives by the working oil discharged from the pump 1, the directional control valve 3 provided in the flow passage connecting the pump 1 with the fluid pressure motor (hydraulic motor 2) and which switches the rotating direction of the fluid pressure motor (hydraulic motor 2), and the counterbalance valve 10 provided between the directional control valve 3 in the flow passage and the fluid pressure motor (hydraulic motor 2).
  • the fluid pressure control device 100 further includes the neutral state detecting unit (position detecting sensor 5a) that detects that the directional control valve 3 is in the neutral state, and the inclination detecting unit (inclination sensor 30) that detects the tilt angle of the vehicle body, and the flow rate control valves 12a and 12b are controlled with accordance with the tilt angle detected by the inclination detecting unit (inclination sensor 30) when the neutral position detecting unit (position detecting sensor 5a) detects the neutral state.
  • the neutral state detecting unit position detecting sensor 5a
  • inclination detecting unit inclination sensor 30
  • the flow rate control valves 12a and 12b are controlled in accordance with the tilt angle of the vehicle body when the directional control valve 3 is in the neutral state; thus, the switching speed of the control valve 11 when the fluid pressure motor (hydraulic motor 2) stops can be adjusted in accordance with the tilt angle of the vehicle body. Therefore, the braking of the fluid pressure motor (hydraulic motor 2) can be suitably performed in the state in which the vehicle body is tilted. This allows for suitably adjusting the braking distance of the vehicle body with accordance with the tilted state of the vehicle body.
  • the fluid pressure control device 100 further includes the flow rate detecting unit (flow rate sensor 50) that detects the flow rate of the working oil flowing to the fluid pressure motor (hydraulic motor 2), and the flow rate control valves 12a and 12b are controlled in accordance with the detected flow rate detected by the flow rate detecting unit (flow rate sensor 50).
  • flow rate sensor 50 the flow rate detecting unit that detects the flow rate of the working oil flowing to the fluid pressure motor (hydraulic motor 2)
  • the flow rate control valves 12a and 12b are controlled in accordance with the detected flow rate detected by the flow rate detecting unit (flow rate sensor 50).
  • the flow rate control valves 12a and 12b are controlled in accordance with the flow rate detected by the flow rate detecting unit (flow rate sensor 50), and thus the switching speed of the control valve 11 can be adjusted in accordance with the rotational speed of the fluid pressure motor (hydraulic motor 2). This thus allows for suitably adjusting the braking distance of the vehicle body in accordance with the rotational speed of the fluid pressure motor (hydraulic motor 2).
  • the fluid pressure control device 100 further includes the differential pressure detecting unit (differential pressure gauge 70) that detects the differential pressure between the supply side and the discharge side of the fluid pressure motor (hydraulic motor 2), and the rotation speed detecting unit (rotation speed sensor 80) that detects the rotation speed of the fluid pressure motor (hydraulic motor 2); and the flow rate control valves 12a and 12b are controlled in accordance with the differential pressure detected by the differential pressure detecting unit (differential pressure gauge 70) and the rotation speed detected by the rotation speed detecting unit (rotation speed sensor 80).
  • the differential pressure detecting unit differential pressure gauge 70
  • rotation speed detecting unit rotation speed sensor 80
  • the working state of the fluid pressure motor (hydraulic motor 2) can be detected based on the differential pressure between the supply side and the discharge side of the fluid pressure motor (hydraulic motor 2) and the rotation speed of the fluid pressure motor (hydraulic motor 2). Since the measurement errors in the differential pressure between the supply side and the discharge side in the fluid pressure motor (hydraulic motor 2) and the rotation speed of the fluid pressure motor (hydraulic motor 2) are small, the flow rate can be calculated with good accuracy. Accordingly, the flow rate control valves 12a and 12b can be controlled more accurately. This thus allows for more suitably adjusting the braking distance of the vehicle body in accordance with the rotational speed of the fluid pressure motor (hydraulic motor 2).
  • an oil temperature sensor that detects an oil temperature may be provided in the supply and discharge flow passages 22a and 22b. Since viscosity of the working oil can be calculated from the detected oil temperature, the flow rate control valves 12a and 12b can be controlled with better accuracy by controlling using correction factors (or a map) in accordance with the viscosity.
  • the hydraulic motor 2 is described using one for traveling as an example, however the hydraulic motor 2 may be used for revolving.
  • a sensor that detects a position of the valve body of the directional control valve 3 may be provided.
  • the neutral state of the directional control valve 3 may be detected by detecting a pressure of the pilot chambers 3a and 3b or the pilot flow passage communicating with the pilot chambers 3a and 3b.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mining & Mineral Resources (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Fluid-Pressure Circuits (AREA)
  • Operation Control Of Excavators (AREA)
EP16865999.3A 2015-11-20 2016-09-09 Counter balance valve and fluid pressure control device provided with counter balance valve Withdrawn EP3379090A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2015227811A JP6268146B2 (ja) 2015-11-20 2015-11-20 カウンタバランス弁及びカウンタバランス弁を備えた流体圧制御装置
PCT/JP2016/076678 WO2017085996A1 (ja) 2015-11-20 2016-09-09 カウンタバランス弁及びカウンタバランス弁を備えた流体圧制御装置

Publications (1)

Publication Number Publication Date
EP3379090A1 true EP3379090A1 (en) 2018-09-26

Family

ID=58718082

Family Applications (1)

Application Number Title Priority Date Filing Date
EP16865999.3A Withdrawn EP3379090A1 (en) 2015-11-20 2016-09-09 Counter balance valve and fluid pressure control device provided with counter balance valve

Country Status (4)

Country Link
EP (1) EP3379090A1 (ja)
JP (1) JP6268146B2 (ja)
KR (1) KR20180066210A (ja)
WO (1) WO2017085996A1 (ja)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3779062A4 (en) * 2018-03-28 2021-05-26 Sumitomo (S.H.I.) Construction Machinery Co., Ltd. SHOVEL
CN113348301A (zh) * 2019-02-08 2021-09-03 川崎重工业株式会社 液压泵流量校正系统

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6903541B2 (ja) * 2017-10-03 2021-07-14 株式会社クボタ 作業機の油圧システム

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5715157A (en) * 1980-07-03 1982-01-26 Kawasaki Heavy Ind Ltd Brake valve
JP2537617Y2 (ja) * 1991-06-19 1997-06-04 株式会社小松製作所 カウンタバランス弁
JPH08277547A (ja) * 1995-04-07 1996-10-22 Shin Caterpillar Mitsubishi Ltd 車両の走行系制御回路

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3779062A4 (en) * 2018-03-28 2021-05-26 Sumitomo (S.H.I.) Construction Machinery Co., Ltd. SHOVEL
US11913194B2 (en) 2018-03-28 2024-02-27 Sumitomo Construction Machinery Co., Ltd. Shovel
CN113348301A (zh) * 2019-02-08 2021-09-03 川崎重工业株式会社 液压泵流量校正系统
CN113348301B (zh) * 2019-02-08 2024-03-08 川崎重工业株式会社 液压泵流量校正系统

Also Published As

Publication number Publication date
JP6268146B2 (ja) 2018-01-24
WO2017085996A1 (ja) 2017-05-26
JP2017096368A (ja) 2017-06-01
KR20180066210A (ko) 2018-06-18

Similar Documents

Publication Publication Date Title
US10202986B2 (en) Hydraulic drive system
CN102549313B (zh) 作业车辆
JP5628832B2 (ja) 流体力を補償する油圧制御システム
US9932957B2 (en) Switchable hydrostatic adjusting device
EP1905903B1 (en) Backhoe hydraulic system
US9328757B2 (en) Hydraulic system for work machine
CN102483156A (zh) 作业车辆
US6564549B2 (en) Displacement control device for hydraulic pump and brake control device for hydraulic motor
EP3379090A1 (en) Counter balance valve and fluid pressure control device provided with counter balance valve
US9995018B2 (en) Control system of hybrid construction machine
CN110914503B (zh) 作业车辆以及作业车辆的控制方法
JP2009522147A (ja) 車両操舵装置および方法
US8868306B1 (en) Wheel loader
JP2020002991A (ja) 作業機の油圧システム
JP2019065956A (ja) 作業機械
JP2024102120A (ja) 作業機
JP2014190255A (ja) ポンプ制御装置
JP2020008171A (ja) 作業機の油圧システム
JP2017096368A5 (ja)
JP2017053413A (ja) 作業機の油圧システム
JPH0689848B2 (ja) 液圧システム
JP2015004369A (ja) 油圧モータの制御装置
JP2020002992A (ja) 作業機の油圧システム
JP2019143806A (ja) 作業機の油圧システム
JP2014190434A (ja) 作業機

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20180620

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

AX Request for extension of the european patent

Extension state: BA ME

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN

18W Application withdrawn

Effective date: 20190115