EP4628736A1 - Fluid pressure control device - Google Patents

Fluid pressure control device

Info

Publication number
EP4628736A1
EP4628736A1 EP23897304.4A EP23897304A EP4628736A1 EP 4628736 A1 EP4628736 A1 EP 4628736A1 EP 23897304 A EP23897304 A EP 23897304A EP 4628736 A1 EP4628736 A1 EP 4628736A1
Authority
EP
European Patent Office
Prior art keywords
passage
valve
pressure
primary
pilot
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.)
Pending
Application number
EP23897304.4A
Other languages
German (de)
French (fr)
Inventor
Kosuke SHIBUYA
Koki Ishibashi
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 EP4628736A1 publication Critical patent/EP4628736A1/en
Pending legal-status Critical Current

Links

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
    • E02F9/22—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
    • E02F9/2264—Arrangements or adaptations of elements for hydraulic drives
    • E02F9/2267—Valves or distributors
    • 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
    • E02F9/2278—Hydraulic circuits
    • E02F9/2285—Pilot-operated 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
    • E02F9/2278—Hydraulic circuits
    • E02F9/2296—Systems with a variable displacement pump
    • 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
    • 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
    • F15B13/0433—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 pressure control 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
    • F15B13/06—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with two or more servomotors
    • F15B13/08—Assemblies of units, each for the control of a single servomotor only
    • F15B13/0803—Modular units
    • F15B13/0807—Manifolds
    • F15B13/0814—Monoblock manifolds
    • 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
    • F15B13/06—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with two or more servomotors
    • F15B13/08—Assemblies of units, each for the control of a single servomotor only
    • F15B13/0803—Modular units
    • F15B13/0878—Assembly of modular units
    • F15B13/0885—Assembly of modular units using valves combined with other components
    • F15B13/0892—Valves combined with fluid components
    • 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
    • F15B13/06—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with two or more servomotors
    • F15B13/08—Assemblies of units, each for the control of a single servomotor only
    • F15B13/0803—Modular units
    • F15B13/0807—Manifolds
    • F15B13/0817—Multiblock manifolds
    • 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
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/2053—Type of pump
    • F15B2211/20546—Type of pump variable capacity
    • 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
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/20576—Systems with pumps with multiple pumps
    • 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
    • F15B2211/31—Directional control characterised by the positions of the valve element
    • F15B2211/3105—Neutral or centre positions
    • F15B2211/3111—Neutral or centre positions the pump port being closed in the centre position, e.g. so-called closed centre
    • 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
    • F15B2211/327—Directional 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
    • F15B2211/30—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
    • 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
    • F15B2211/50—Pressure control
    • F15B2211/505—Pressure control characterised by the type of pressure control means
    • F15B2211/50554—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure downstream of the pressure control means, e.g. pressure reducing 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

Definitions

  • the present invention relates to a fluid pressure control device.
  • JP2019-94973A discloses a configuration of a construction machine such as a hydraulic excavator including a variable displacement hydraulic pump that discharges hydraulic oil, a hydraulic actuator, and a control valve that controls a supply amount and a supply direction of hydraulic oil from the hydraulic pump to the hydraulic actuator.
  • the control valve includes a housing, a spool movably accommodated in the housing, and a pair of springs biasing the spool to an initial position.
  • the housing includes a pair of actuator ports connected to the hydraulic actuator by a pair of actuator oil passages, and a pair of pilot ports to which hydraulic oil (pilot oil) for moving the spool is guided.
  • the construction machine includes a pressure reducing valve that generates a primary pressure by lowering a pressure of the hydraulic oil discharged from the hydraulic pump, and a solenoid proportional pressure reducing valve that controls a pressure (secondary pressure) acting on the pilot ports by the primary pressure being guided.
  • a pressure reducing valve that generates a primary pressure by lowering a pressure of the hydraulic oil discharged from the hydraulic pump
  • a solenoid proportional pressure reducing valve that controls a pressure (secondary pressure) acting on the pilot ports by the primary pressure being guided.
  • the control valve 10 is a spool valve having four ports and three positions. In the present embodiment, a plurality of control valves 10 having the same configuration are provided corresponding to the respective hydraulic cylinders 6. In the control valve 10, a secondary pilot pressure is guided to a pair of pilot pressure chambers 11 through a pilot passage 16 to be described later in accordance with an operation direction and an operation amount of an operation lever 9 by an operator, and the position of the control valve 10 is switched. The position of the control valve 10 is switched among a neutral position 10A, an extension position 10B, and a contraction position 10C in accordance with a magnitude of the secondary pilot pressure supplied to the pair of pilot pressure chambers 11. The control of the control valve 10 will be described in detail later.
  • the controller 8 is implemented by a microcomputer including a central processing unit (CPU) that performs arithmetic processing, a read-only memory (ROM) that stores a control program and the like executed by the CPU, and a random access memory (RAM) that stores an arithmetic result and the like of the CPU.
  • the controller 8 may be implemented by a single microcomputer or a plurality of microcomputers.
  • the main valve block 1 can be made common regardless of the presence or absence of the pilot pump 90.
  • the intra-spool passage 53 communicates with the second valve accommodation hole 42, and the pressure of the pilot oil in the intra-spool passage 53 decreases. Accordingly, the primary pilot pressure guided to the solenoid proportional pressure reducing valve 7 through the second primary pressure passage 26 can be kept constant regardless of a magnitude of the pressure of a pilot fluid guided through the second introduction passage 35.
  • the spool 50 has the main body 51 and is formed to have a uniform outer diameter.
  • the spool 50 may further include, in addition to the main body 51, a large-diameter portion 58 having a larger diameter than the main body 51.
  • the large-diameter portion 58 is accommodated in the first sub-accommodation hole 41b.
  • the first sub-accommodation hole 41b is divided, by the large-diameter portion 58, into a primary pressure chamber 39 communicating with the second primary pressure passage 26 and a damper chamber 40 communicating with the primary pressure chamber 39.
  • the damper chamber 40 is expanded and contracted by the large-diameter portion 58 in accordance with movement of the spool 50.
  • the damper chamber 40 is provided on a second valve accommodation hole 42 side (the right side in FIG. 7 ) in the first sub-accommodation hole 41b.
  • An outer diameter of the large-diameter portion 58 is slightly smaller than an inner diameter of the first sub-accommodation hole 41b. Therefore, a gap 59 is formed between an outer peripheral surface of the large-diameter portion 58 and an inner peripheral surface of the first sub-accommodation hole 41b. Since the damper chamber 40 communicates with the primary pressure chamber 39 through the gap 59, a pilot fluid is supplied to and discharged from the damper chamber 40 in accordance with movement of the spool 50.
  • the pilot fluid is supplied from the primary pressure chamber 39 to the damper chamber 40 through the gap 59.
  • the fluid pressure control device 100 operates and the pressure of the second introduction passage 35 increases, the spool 50 moves to the right side in FIG. 7 against the biasing force of the spring 60.
  • the pilot fluid in the damper chamber 40 is discharged to the primary pressure chamber 39 through the gap 59.
  • the second throttle 55 communicates with the second valve accommodation hole 42 and the pressure in the intra-spool passage 53 and the second introduction passage 35 decreases, the spool 50 moves to the left side in FIG. 7 by the biasing force of the spring 60, and at this time, the pilot fluid is supplied from the primary pressure chamber 39 to the damper chamber 40 through the gap 59.
  • the damper chamber 40 is defined by the large-diameter portion 58, and when the pressure in the second introduction passage 35 increases, the spool 50 moves while discharging the pilot fluid in the damper chamber 40 to the primary pressure chamber 39. Therefore, an amount of movement of the spool 50 is reduced as compared with a case where the spool 50 does not have the large-diameter portion 58. Accordingly, even when the pressure in the second introduction passage 35 rapidly increases, the rapid movement of the spool 50 is limited, and an opening area of the intra-spool passage 53 (second throttle 55) opening to the second valve accommodation hole 42 does not rapidly increase. Therefore, the pressure in the second primary pressure passage 36 is prevented from decreasing more than necessary, and the occurrence of hunting of the spool 50 can be prevented.
  • the primary pressure chamber 39 is open to an outer surface of the sub-valve block 2, and at the time of assembly, the spool 50 is attached from the opening, and the large-diameter portion 58 is accommodated in the first sub-accommodation hole 41b.
  • the second introduction passage 35 and the second primary pressure passage 36 communicate with each other through a third throttle 56 provided on an end 50a side of the first throttle 54. Accordingly, the pressure loss is smaller than in the case where the second introduction passage 35 and the second primary pressure passage 36 communicate with each other through the groove 50b (see FIGS. 3 to 5 ).
  • the fluid pressure control device 100 is configured to control the hydraulic cylinder 6 as an actuator driven by a working fluid discharged from the hydraulic pump 5 as a pump, and the fluid pressure control device 100 includes the control valve 10 that controls a flow of the working fluid to be supplied to and discharged from the hydraulic cylinder 6, the solenoid proportional pressure reducing valve 7 as a solenoid valve that generates pilot pressure for controlling the control valve 10, the main valve block 1 that is provided with the control valve 10 and the solenoid proportional pressure reducing valve 7, and the sub-valve block 2 that is detachably provided in the main valve block 1.
  • the first introduction passage 25, the first primary pressure passage 26, and the first drain passage 27 are formed to open to the outer surface 1a of the main valve block 1, and in the sub valve block 2, openings 2a, 2b, and 2c that are capable of respectively communicating with the first introduction passage 25, the first primary pressure passage 26, and the first drain passage 27 are formed in the outer surface 2d, and the primary pressure generating valve 30 that is capable of generating a primary pilot pressure by reducing a pressure of a pilot fluid guided through the first introduction passage 25 and guiding the primary pilot pressure to the first primary pressure passage 26 is provided.
  • the main valve block 1 can be made common regardless of the presence or absence of the pilot pump 90.
  • the spool 50 is moved by a balance between a pressure of a fluid downstream of the first throttle 54 in the intra-spool passage 53 and the biasing force of the spring 60, and the second primary pressure passage 36 communicates with the second introduction passage 35 or the second drain passage 37 through the intra-spool passage 53 in accordance with the movement of the spool 50.
  • the primary pilot pressure guided to the solenoid proportional pressure reducing valve 7 through the second primary pressure passage 36 can be kept constant regardless of the magnitude of the pressure of the pilot fluid guided through the second introduction passage 35.
  • the spool 50 further includes the main body 51 and the large-diameter portion 58 formed to have a larger diameter than the main body 51.
  • the first valve accommodation hole 41 includes the main accommodating hole 41a in which the main body 51 slides, and the first sub-accommodation hole 41b having a larger inner diameter than the main accommodation hole 41a and serving as a sub-accommodation hole in which the large-diameter portion 58 is accommodated.
  • the first sub-accommodation hole 41b is divided into the primary pressure chamber 39 communicating with the second primary pressure passage 36 and the damper chamber 40 communicating with the primary pressure chamber 39 and expanded and contracted by the large-diameter portion 58 in accordance with movement of the spool 50.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Mechanical Engineering (AREA)
  • Mining & Mineral Resources (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Fluid-Pressure Circuits (AREA)

Abstract

A fluid pressure control device (100) includes a main valve block (1) and a sub-valve block (2), the main valve block (1) includes a supply passage (20), a first introduction passage (25), a first primary pressure passage (26), and a first drain passage (27), the first introduction passage (25), the first primary pressure passage (26), and the first drain passage (27) are formed to open to an outer surface (1a) of the main valve block (1), and in the sub-valve block (2), openings (2a, 2b, 2c) capable of respectively communicating with the first introduction passage (25), the first primary pressure passage (26), and the first drain passage (27) are formed in an outer surface (2d), and a primary pressure generating valve (30) capable of generating a primary pilot pressure and guiding the primary pilot pressure to the first primary pressure passage (26) is provided.

Description

    TECHNICAL FIELD
  • The present invention relates to a fluid pressure control device.
    • BACKGROUND ART
  • JP2019-94973A discloses a configuration of a construction machine such as a hydraulic excavator including a variable displacement hydraulic pump that discharges hydraulic oil, a hydraulic actuator, and a control valve that controls a supply amount and a supply direction of hydraulic oil from the hydraulic pump to the hydraulic actuator. The control valve includes a housing, a spool movably accommodated in the housing, and a pair of springs biasing the spool to an initial position. The housing includes a pair of actuator ports connected to the hydraulic actuator by a pair of actuator oil passages, and a pair of pilot ports to which hydraulic oil (pilot oil) for moving the spool is guided. The construction machine includes a pressure reducing valve that generates a primary pressure by lowering a pressure of the hydraulic oil discharged from the hydraulic pump, and a solenoid proportional pressure reducing valve that controls a pressure (secondary pressure) acting on the pilot ports by the primary pressure being guided. When pilot oil is supplied to the pilot ports, the spool is moved.
    • SUMMARY OF INVENTION
  • In the construction machine as described in JP2019-94973A , a discharge pressure of the hydraulic pump is reduced by the pressure reducing valve to generate a primary pressure, pilot oil of a primary pressure is guided to the solenoid proportional pressure reducing valve to generate a secondary pressure, and pilot oil of a secondary pressure is guided to a pilot chamber. However, if the pressure reducing valve is provided in the housing of the control valve, the oil passage becomes complicated and the housing becomes large in size.
  • Further, in the construction machine described in JP2019-94973A , depending on the need of a user, the discharge pressure of the pilot pump may be maintained at the primary pressure and guided to the solenoid proportional pressure reducing valve. However, when the pressure reducing valve is provided in the housing of the control valve, it is difficult to form an oil passage for guiding only the discharge pressure of the pilot pump to the solenoid proportional pressure reducing valve, and it is difficult to guide the discharge pressure of the pilot pump to the solenoid proportional pressure reducing valve as it is.
  • It is an object of the present invention to provide a fluid pressure control device that can reduce an increase in a size of a housing, and can guide a discharge pressure of a pilot pump to a solenoid valve as a primary pressure as necessary.
    • MEANS FOR SOLVING THE PROBLEM
  • According to one aspect of the present invention, a fluid pressure control device for controlling an actuator driven by a working fluid discharged from a pump, the fluid pressure control device includes: a control valve configured to control a flow of the working fluid to be supplied to and discharged from the actuator; a solenoid valve configured to generate a pilot pressure for controlling the control valve; a main valve block provided with the control valve and the solenoid valve; and a sub-valve block detachably attached to the main valve block, the main valve block includes, a supply passage configured to supply the working fluid discharged from the pump is supplied, a first introduction passage branching from an upstream side of the control valve in the supply passage and capable of guiding a part of the fluid discharged from the pump as a pilot fluid to the sub-valve block, a first primary pressure passage for guiding a primary pilot pressure from the sub-valve block or a pilot pump to the solenoid valve, and a first drain passage capable of discharging a drain fluid from the sub-valve block to a tank, the first introduction passage, the first primary pressure passage, and the first drain passage are formed to open to an outer surface of the main valve block, and in the sub-valve block, openings capable of respectively communicating with the first introduction passage, the first primary pressure passage, and the first drain passage are formed in an outer surface, and a primary pressure generating valve capable of generating a primary pilot pressure by reducing a pressure of the pilot fluid guided through the first introduction passage and guiding the primary pilot pressure to the first primary pressure passage is provided.
    • BRIEF DESCRIPTION OF DRAWINGS
    • FIG. 1 is a fluid pressure circuit diagram of a fluid pressure control device according to an embodiment of the present invention, showing a state where a sub-valve block is attached to a main valve block.
    • FIG. 2 is a side view showing a mounting surface of the sub-valve block provided in the main valve block.
    • FIG. 3 is a sectional view showing the sub-valve block, showing a state where a spool is seated on a first plug.
    • FIG. 4 is a sectional view showing the sub-valve block, showing a state where the spool is separated from the first plug.
    • FIG. 5 is a sectional view showing the sub-valve block, showing a state where the spool is further moved to a right side from the state shown in FIG. 4.
    • FIG. 6 is a fluid pressure circuit diagram of the fluid pressure control device according to the embodiment of the present invention, showing a state where a pilot pump is connected to the main valve block.
    • FIG. 7 is a sectional view showing a sub-valve block according to a modification of the embodiment of the present invention, which corresponds to FIG. 3.
    DESCRIPTION OF EMBODIMENTS
  • A fluid pressure control device 100 according to an embodiment of the present invention will be described with reference to the drawings.
  • The fluid pressure control device 100 is a device that controls an actuator driven by a working fluid discharged from a pump, and is mounted on a work machine such as a construction machine, an agricultural machine, or an industrial machine. Hereinafter, a case where the fluid pressure control device 100 is mounted on a hydraulic excavator and is used to control operations of actuators such as a hydraulic motor for traveling and a hydraulic cylinder for driving a boom, an arm, a bucket, and the like will be described. Although an example in which hydraulic oil is used as the working fluid for driving the actuator of a hydraulic excavator will be described, another fluid such as working water may be used as the working fluid.
  • First, an overall configuration of the fluid pressure control device 100 will be described with reference to a fluid pressure circuit diagram of FIG. 1.
  • The fluid pressure control device 100 includes a variable displacement hydraulic pump 5 serving as a pump, a hydraulic cylinder 6 serving as an actuator that is driven by the hydraulic oil discharged from the hydraulic pump 5, a supply passage 20 that supplies the hydraulic oil discharged from the hydraulic pump 5, control valves 10 that are provided in the supply passage 20 and control a flow of the hydraulic oil supplied to and discharged from the hydraulic cylinder 6, a pair of actuator passages 21 that are connected to the control valves 10 and the hydraulic cylinder 6 and through which the hydraulic oil to be supplied to and discharged from the hydraulic cylinder 6 flows, and a discharge passage 22 that is connected to the control valves 10 and tanks 4 and guides the hydraulic oil discharged from the hydraulic cylinder 6 to the tanks 4. A plurality of hydraulic cylinders 6 and control valves 10 are provided, and one hydraulic cylinder 6 and two control valves 10a, 10b are representatively shown in FIG. 1.
  • The hydraulic pump 5 is driven by an engine mounted on the hydraulic excavator. The hydraulic pump 5 is not limited thereto, and may be driven by an electric motor. The hydraulic cylinder 6 includes a cylinder tube 6a, a piston rod 6b inserted into the cylinder tube 6a, and a piston 6c provided on an end of the piston rod 6b and sliding along an inner peripheral surface of the cylinder tube 6a. The inside of the cylinder tube 6a is partitioned into a rod-side chamber 6d and a bottom-side chamber 6e by a piston 6c. The hydraulic oil is supplied to and discharged from the rod-side chamber 6d and the bottom-side chamber 6e through the actuator passages 21.
  • The supply passages 20 are connected to the hydraulic pump 5 and the control valves 10, and guide the hydraulic oil discharged from the hydraulic pump 5 to the control valves 10. One actuator passage 21a of the pair of actuator passages 21 is connected to the control valve 10 and the rod-side chamber 6d of the hydraulic cylinder 6, and the other actuator passage 21b is connected to the control valve 10 and the bottom-side chamber 6e of the hydraulic cylinder 6. One of the pair of actuator passages 21 is connected to the supply passage 20 and the other is connected to the discharge passage 22 according to a position of the control valve 10.
  • The control valve 10 is a spool valve having four ports and three positions. In the present embodiment, a plurality of control valves 10 having the same configuration are provided corresponding to the respective hydraulic cylinders 6. In the control valve 10, a secondary pilot pressure is guided to a pair of pilot pressure chambers 11 through a pilot passage 16 to be described later in accordance with an operation direction and an operation amount of an operation lever 9 by an operator, and the position of the control valve 10 is switched. The position of the control valve 10 is switched among a neutral position 10A, an extension position 10B, and a contraction position 10C in accordance with a magnitude of the secondary pilot pressure supplied to the pair of pilot pressure chambers 11. The control of the control valve 10 will be described in detail later.
  • Further, the fluid pressure control device 100 includes: a pilot passage 16 that is branched from the supply passage 20 and guides the pilot pressure for controlling the control valves 10 to the pair of pilot pressure chambers 11; a primary pressure generating valve 30 that is provided in the pilot passage 16 and generates a primary pilot pressure; a drain passage 17 that guides the drain oil from the primary pressure generating valve 30 to the tank 4; solenoid proportional pressure reducing valves 7 that are provided in the pilot passage 16 and serve as solenoid valves for generating a secondary pilot pressure for controlling the control valves 10 from the primary pilot pressure; and a controller 8 that controls the operation of the solenoid proportional pressure reducing valves 7.
  • The pilot passage 16 branches from an upstream side of the control valves 10 in the supply passage 20, and is connected to the pair of pilot pressure chambers 11 of the control valves 10. A part of the hydraulic oil discharged from the hydraulic pump 5 is guided to the pilot passage 16 as pilot oil. The pilot passage 16 is provided with the primary pressure generating valve 30 on an upstream side, is branched into two branch passages 16a, 16b downstream of the primary pressure generating valve 30, and the branch passages 16a, 16b are connected to the pair of pilot pressure chambers 11a, 11b, respectively. The solenoid proportional pressure reducing valve 7 are provided in each of the two branch passages 16a, 16b.
  • The primary pressure generating valve 30 reduces the pressure of the pilot oil guided from the hydraulic pump 5 to the pilot passage 16, and generates a primary pilot pressure guided to the solenoid proportional pressure reducing valve 7. The primary pressure generating valve 30 operates so that the primary pilot pressure is constantly kept constant regardless of the pressure of the pilot oil guided from the hydraulic pump 5 to the supply passage 20. A detailed configuration of the primary pressure generating valve 30 will be described later.
  • The solenoid proportional pressure reducing valves 7 are electrically connected to the controller 8, and generate a secondary pilot pressure according to a signal from the controller 8. In the pilot passage 16, a primary pilot pressure is generated by the primary pressure generating valve 30, the primary pilot pressure is guided to the two solenoid proportional pressure reducing valves 7, and a secondary pilot pressure is generated by the solenoid proportional pressure reducing valves 7 and is guided to the pair of pilot pressure chambers 11. Accordingly, the control valves 10 are controlled. Further, the discharge oil is discharged from the solenoid proportional pressure reducing valves 7 through a passage 18. The passage 18 communicates with the drain passage 17, and the discharge oil from the solenoid proportional pressure reducing valves 7 is discharged to the tank 4 through the passage 18 and the drain passage 17.
  • The controller 8 is implemented by a microcomputer including a central processing unit (CPU) that performs arithmetic processing, a read-only memory (ROM) that stores a control program and the like executed by the CPU, and a random access memory (RAM) that stores an arithmetic result and the like of the CPU. The controller 8 may be implemented by a single microcomputer or a plurality of microcomputers.
  • The controller 8 transmits a control signal corresponding to the operation direction and the operation amount of the operation lever 9 to the solenoid proportional pressure reducing valve 7 to control the solenoid proportional pressure reducing valve 7. When the operation lever 9 is not operated, the controller 8 performs control so that the secondary pilot pressure is not guided to the pair of pilot pressure chambers 11. Accordingly, the control valve 10a is held at the neutral position 10A by a pair of springs 14. When the control valve 10a is at the neutral position 10A, the pair of actuator passages 21 do not communicate with either the supply passage 20 or the discharge passage 22. When the operation lever 9 is operated to switch the control valve 10 to the extension position 10B, the controller 8 controls the solenoid proportional pressure reducing valves 7 so that the secondary pilot pressure is guided to the pilot pressure chamber 11a. Accordingly, the control valve 10a is switched to the extension position 10B against a biasing force of the springs 14. When the control valve 10a is at the extension position 10B, the actuator passage 21b communicates with the supply passage 20, and the hydraulic oil is guided from the hydraulic pump 5 to the bottom-side chamber 6e. The actuator passage 21a communicates with the discharge passage 22, the hydraulic oil in the rod-side chamber 6d is discharged to the tank 4, and the hydraulic cylinder 6 extends.
  • When the operation lever 9 is operated to switch the control valve 10 to the contraction position 10C, the controller 8 controls the solenoid proportional pressure reducing valves 7 so that the secondary pilot pressure is guided to the pilot pressure chamber 11b. Accordingly, the control valve 10a is switched to the contraction position 10C against the biasing force of the springs 14. When the control valve 10a is at the contraction position 10C, the actuator passage 21b communicates with the discharge passage 22, and the hydraulic oil in the bottom-side chamber 6e is discharged to the tank 4. The actuator passage 21a communicates with the supply passage 20, the hydraulic oil is guided from the hydraulic pump 5 to the rod-side chamber 6d, and the hydraulic cylinder 6 contracts. In this way, the control valve 10a is controlled.
  • Next, a main valve block 1 and a sub-valve block 2 in which the above-described fluid pressure circuit is formed will be described in detail.
  • The fluid pressure control device 100 includes the main valve block 1 and the sub-valve block 2 detachably provided in the main valve block 1. FIG. 1 shows a region formed in the main valve block 1 and a region formed in the sub-valve block 2 in the fluid pressure circuit. As shown in FIG. 1, the pilot passage 16 is formed over the main valve block 1 and the sub-valve block 2, and the primary pressure generating valve 30 is provided in the sub-valve block 2. As described above, in the fluid pressure control device 100, the primary pressure generating valve 30 is provided not in the main valve block 1 but in a sub-block that is detachable from the main valve block 1. Accordingly, the oil passage of the main valve block 1 is prevented from becoming complicated. This will be described in detail below.
  • In the main valve block 1, the control valves 10 and the solenoid proportional pressure reducing valves 7 are provided, and the supply passage 20, the actuator passage 21, and the discharge passage 22 are formed. A part of the pilot passage 16 and a part of the drain passage 17 are formed in the main valve block 1. Specifically, the main valve block 1 includes a first introduction passage 25 that is at the most upstream side of the pilot passage 16, a first primary pressure passage 26 which is a part of the pilot passage 16 and guides the primary pilot pressure generated by the primary pressure generating valve 30 into the solenoid proportional pressure reducing valves 7, a first drain passage 27 which is a part of the drain passage 17 and discharges the drain oil from the primary pressure generating valve 30 to the tank 4, and the branch passages 16a, 16b of the pilot passage 16. The first introduction passage 25 branches from an upstream side of the control valves 10 in the supply passage 20, and guides a part of the hydraulic oil discharged from the hydraulic pump 5 to the sub-valve block 2 as pilot oil. The first primary pressure passage 26 guides the primary pilot pressure generated by the primary pressure generating valve 30 of the sub-valve block 2 to the solenoid proportional pressure reducing valve 7. The first drain passage 27 discharges drain oil from the primary pressure generating valve 30 of the sub-valve block 2 to the tank 4.
  • As shown in FIG. 2, the first introduction passage 25, the first primary pressure passage 26, and the first drain passage 27 are formed to open to an outer surface 1a of the main valve block 1. A spool hole 1b for accommodating spools of the plurality of control valves 10 is also formed in the outer surface 1a of the main valve block 1.
  • As shown in FIGS. 1 and 3, the primary pressure generating valve 30 is provided in the sub-valve block 2, and a part of the pilot passage 16 and a part of the drain passage 17 are formed. As shown in FIG. 3, the sub-valve block 2 is attached to an outer surface 1a where the first introduction passage 25, the first primary pressure passage 26, and the first drain passage 27 formed in the main valve block 1 are opened via a fastening member such as a bolt by bringing an outer surface 2d into contact with the outer surface 1a. In the sub-valve block 2, openings 2a, 2b, and 2c respectively communicating with the first introduction passage 25, the first primary pressure passage 26, and the first drain passage 27 formed in the main valve block 1 are formed in the outer surface 2d.
  • The primary pressure generating valve 30 is capable of generating a primary pilot pressure by reducing the pressure of the pilot oil introduced through the first introduction passage 25 of the main valve block 1 and guiding the primary pilot pressure to the first primary pressure passage 26 of the main valve block 1. As shown in FIGS. 1 and 3, the primary pressure generating valve 30 includes a second introduction passage 35 formed in the sub-valve block 2 and capable of communicating with the first introduction passage 25 through the opening 2a (see FIG. 3), a second primary pressure passage 36 formed in the sub-valve block 2 and capable of communicating with the first primary pressure passage 26 through an opening 2b (see FIG. 3), and a second drain passage 37 formed in the sub-valve block 2 and capable of communicating with the first drain passage 27 through the opening 2c (see FIG. 3).
  • The second introduction passage 35 is a part of the pilot passage 16, and guides a part of the hydraulic oil discharged from the hydraulic pump 5 to the primary pressure generating valve 30 as pilot oil. That is, a part of the hydraulic oil discharged from the hydraulic pump 5 is guided to the primary pressure generating valve 30 through the first introduction passage 25 of the main valve block 1 and the second introduction passage 35 of the sub-valve block 2. The second primary pressure passage 36 is a part of the pilot passage 16, and guides the primary pilot pressure generated by the primary pressure generating valve 30 to the solenoid proportional pressure reducing valve 7 through the first primary pressure passage 26 of the main valve block 1. The second drain passage 37 is a part of the drain passage 17, and discharges the drain oil of the primary pressure generating valve 30 to the tank 4 through the first drain passage 27 of the main valve block 1.
  • Next, a configuration in which the primary pressure is generated by the primary pressure generating valve 30 will be described. As shown in FIG. 3, the primary pressure generating valve 30 includes a first valve accommodation hole 41 through which the second introduction passage 35 and the second primary pressure passage 36 communicate with each other, a second valve accommodation hole 42 that communicates with the first valve accommodation hole 41, a spool 50 serving as a valve body that is accommodated across the first valve accommodation hole 41 and the second valve accommodation hole 42 and controls the flow of the pilot oil from the second introduction passage 35 to the second primary pressure passage 36, a spring 60 serving as a biasing member that is accommodated in the second valve accommodation hole 42 and biases the spool 50 toward the first valve accommodation hole 41, and a spring seat 70 on which the spring 60 is seated.
  • The first valve accommodation hole 41 opens to an outer surface of the sub-valve block 2, and the opening is sealed by a first plug 61. The second valve accommodation hole 42 is formed to be continuous with the first valve accommodation hole 41 and extend coaxially with the first valve accommodation hole 41, and is formed to have a larger diameter than the first valve accommodation hole 41. The second valve accommodation hole 42 opens to the outer surface of the sub-valve block 2, and the opening is sealed by a second plug 62. The second drain passage 37 communicates with the second valve accommodation hole 42.
  • The first valve accommodation hole 41 includes a main accommodation hole 41a in which the spool 50 (specifically, a main body 51 to be described later) slides, a first sub-accommodation hole 41b and a second sub-accommodation hole 41c each having a larger inner diameter than the main accommodation hole 41a. The main accommodation hole 41a, the first sub-accommodation hole 41b, and the second sub-accommodation hole 41c are formed to extend coaxially. The first sub-accommodation hole 41b communicates with the second primary pressure passage 36, and the second sub-accommodation hole 41c communicates with the second introduction passage 35. The first sub-accommodation hole 41b corresponds to a "sub-accommodation hole" in the claims.
  • The spool 50 is slidably provided in the first valve accommodation hole 41. The spring seat 70 includes a flange portion 71 on which the spring 60 is seated, and a spring guide 72 that guides the spring 60 in contact with an outer peripheral surface of the spring seat 70. The spring seat 70 is accommodated in the second valve accommodation hole 42. In the spring seat 70, the flange portion 71 and the spring guide 72 are integrally formed. The spool 50 is fitted into a recess 71a formed in the center of the flange portion 71 and connected to the spring seat 70. Accordingly, a portion of the spool 50 fitted into the recess 71a is accommodated in the second valve accommodation hole 42, and the other portion is accommodated in the first valve accommodation hole 41. In the present embodiment, the spring 60 is seated on the flange portion 71 of the spring seat 70, and the spool 50 is coupled to the flange portion 71, so that the spool 50 is biased by the spring 60 via the flange portion 71. An end 50a of the spool 50 is seated on the first plug 61. In this state, the flange portion 71 of the spring seat 70 is seated on a bottom surface 42a of the second valve accommodation hole 42. The spool 50 may be provided such that a gap is present between the flange portion 71 and the bottom surface 42a of the second valve accommodation hole 42 in a state where the end 50a is seated on the first plug 61.
  • The spool 50 includes the main body 51 slidable in the first valve accommodation hole 41, an intra-spool passage 53 serving as an intra-valve passage formed inside the spool 50 and allowing the second introduction passage 35 and the second primary pressure passage 36 to communicate with each other, a first throttle 54 serving as a throttle provided in the intra-spool passage 53 and configured to apply resistance to the pilot oil passing therethrough, and a second throttle 55 provided in the intra-spool passage 53 at a position closer to the flange portion 52 than the first throttle 54. In the present embodiment, the spool 50 has a uniform outer diameter.
  • The intra-spool passage 53 is formed to extend in an axial direction in the main body 51, and opens to the end 50a of the spool 50. The first throttle 54 and the second throttle 55 are formed to extend radially inside the spool 50, and open to an outer peripheral surface of the spool 50. The first throttle 54 and the second throttle 55 are formed to have a diameter smaller than that of the intra-spool passage 53 and an equivalent area larger than that of the intra-spool passage 53. When the end 50a of the spool 50 is seated on the first plug 61, the first throttle 54 communicates with the second introduction passage 35, and the second throttle 55 does not communicate with the second introduction passage 35 and the second valve accommodation hole 42. A distance between the first throttle 54 and the second throttle 55 is smaller than a distance between the second sub-accommodation hole 41c and the second valve accommodation hole 42.
  • The spool 50 is moved by a balance between a load due to the pressure of the pilot oil downstream of the first throttle 54 in the intra-spool passage 53 and the biasing force of the spring 60. The second primary pressure passage 36 communicates with the second introduction passage 35 and the second drain passage 37 through the intra-spool passage 53 in accordance with the movement of the spool 50. As shown in FIG. 3, when the fluid pressure control device 100 is not operated, the end 50a of the spool 50 is seated on the first plug 61 by the biasing force of the spring 60. In this state, the first introduction passage 25 and the second primary pressure passage 36 communicate with each other through the intra-spool passage 53 and a groove 50b radially formed in the end 50a of the spool 50.
  • When the fluid pressure control device 100 operates and a part of the hydraulic oil discharged from the hydraulic pump 5 becomes pilot oil and is gradually guided from the supply passage 20 to the intra-spool passage 53 through the first introduction passage 25, the second introduction passage 35, and the first throttle 54, the pressure downstream of the first throttle 54 in the intra-spool passage 53 increases. Accordingly, the spool 50 moves to a right side in FIG. 3 against the biasing force of the spring 60, and the end 50a of the spool 50 is separated from the first plug 61. In this state, the pilot oil in the second introduction passage 35 is guided to the second primary pressure passage 36 while being reduced the pressure by the first throttle 54 through the intra-spool passage 53. Accordingly, the primary pilot pressure is generated by the primary pressure generating valve 30. The primary pilot pressure is guided to the solenoid proportional pressure reducing valve 7 through the second primary pressure passage 36 and the first primary pressure passage 26, and a secondary pilot pressure is generated by the solenoid proportional pressure reducing valve 7 and guided to the pilot pressure chamber 11. Accordingly, the control valves 10 are controlled.
  • In the fluid pressure control device 100, the pressure of the pilot oil guided to the primary pressure generating valve 30 changes according to operation states of a plurality of hydraulic cylinders 6. Specifically, when the number of hydraulic cylinders 6 in operation is reduced, the working fluid supplied from the hydraulic pump 5 to the hydraulic cylinders 6 decreases, and thus the pressure of the pilot oil guided to the primary pressure generating valve 30 increases. When the pressure of the pilot oil guided to the primary pressure generating valve 30 increases, the pressure downstream of the first throttle 54 in the intra-spool passage 53 also increases, and the spool 50 moves to the right side in FIG. 3 against a biasing force of the spring 60. When the pressure downstream of the first throttle 54 in the intra-spool passage 53 exceeds a predetermined pressure, first, as shown in FIG. 4, the first throttle 54 does not communicate with the second introduction passage 35, and the communication between the second introduction passage 35 and the second primary pressure passage 36 is blocked.
  • Immediately thereafter, as shown in FIG. 5, the second throttle 55 communicates with the second valve accommodation hole 42, and the intra-spool passage 53 and the second drain passage 37 communicate with each other through the second valve accommodation hole 42. Accordingly, the pilot oil in the intra-spool passage 53 is discharged to the tank 4 through the second drain passage 37 and the first drain passage 27. At this time, the pressure in the intra-spool passage 53 is prevented from decreasing much more than necessary by the second throttle 55. In this way, an increase in the primary pilot pressure is reduced. Thereafter, when the pressure downstream of the first throttle 54 in the intra-spool passage 53 falls below the predetermined pressure, the spool 50 moves to the left side in FIG. 3 by the biasing force of the spring 60, the communication between the second throttle 55 and the second valve accommodation hole 42 is blocked, the first throttle 54 communicates with the second introduction passage 35 again, and the second introduction passage 35 and the second primary pressure passage 36 communicate with each other again through the intra-spool passage 53. In this way, a decrease in the primary pilot pressure is reduced. Since the distance between the first throttle 54 and the second throttle 55 is smaller than the distance between the second sub-accommodation hole 41c and the second valve accommodation hole 42, the second introduction passage 35 and the second drain passage 37 do not communicate with each other through the intra-spool passage 53 and the second valve accommodation hole 42.
  • As described above, even when the pressure of the pilot oil guided to the primary pressure generating valve 30 changes, after the communication between the intra-spool passage 53 and the second introduction passage 35 is blocked in the primary pressure generating valve 30, the intra-spool passage 53 communicates with the second valve accommodation hole 42, and an increase in the pressure of the pilot oil in the intra-spool passage 53 is reduced. Accordingly, even if the pressure of the pilot oil guided to the primary pressure generating valve 30 changes, the primary pilot pressure guided to the first and second primary pressure passages 26 and 36 can be kept constant. Positions and sizes of the first throttle 54 and the second throttle 55, a spring constant of the spring 60, and the like are designed according to the set pressure of the primary pilot pressure.
  • As described above, in the fluid pressure control device 100, the sub-valve block 2 is attached to the main valve block 1, a part of the hydraulic oil discharged from the hydraulic pump 5 is guided to the sub-valve block 2 through the first introduction passage 25, and the primary pilot pressure generated by the primary pressure generating valve 30 of the sub-valve block 2 is guided to the main valve block 1 through the first primary pressure passage 26. In the fluid pressure control device 100, the primary pressure generating valve 30 is provided not in the main valve block 1 but in the sub-valve block 2. Therefore, an oil passage of the main valve block 1 is simplified, and an increase in size of the main valve block 1 can be reduced.
  • Further, the fluid pressure control device 100 can be used by removing the sub-valve block 2. Specifically, the sub-valve block 2 is removed from the main valve block 1. As shown in FIG. 6, when openings of the first introduction passage 25 and the first drain passage 27 of the main valve block 1 are blocked by plugs 80, the pilot pump 90 is connected to the first primary pressure passage 26 of the main valve block 1. Accordingly, a discharge pressure of the pilot pump 90 is guided to the solenoid proportional pressure reducing valve 7 as a primary pilot pressure. Thus, in the fluid pressure control device 100, the discharge pressure of the pilot pump 90 can be guided to the fluid pressure control device 100 as a primary pilot pressure according to the need of the user. Therefore, the main valve block 1 can be made common regardless of the presence or absence of the pilot pump 90.
  • In the fluid pressure control device 100, when the sub-valve block 2 is attached and used, the hydraulic oil discharged from the hydraulic pump 5 is guided to the primary pressure generating valve 30 to generate a primary pilot pressure. Therefore, it is not necessary to provide a pilot pump different from the hydraulic pump 5 in order to generate the primary pilot pressure, and a manufacturing cost of the fluid pressure control device 100 is reduced.
  • According to the above-described embodiment, the following functions and effects are achieved.
  • In the fluid pressure control device 100, when the sub-valve block 2 is attached to the main valve block 1, a part of the hydraulic oil discharged from the hydraulic pump 5 is guided to the sub-valve block 2 through the first introduction passage 25 as pilot oil, and the primary pilot pressure generated by the primary pressure generating valve 30 of the sub-valve block 2 is guided to the main valve block 1 through the first primary pressure passage 26. Thus, in the fluid pressure control device 100, the primary pressure generating valve 30 is provided not in the main valve block 1 but in the sub-valve block 2. Therefore, an oil passage of the main valve block 1 is simplified, and an increase in size of the main valve block 1 can be reduced. On the other hand, by removing the sub-valve block 2 from the main valve block 1, blocking the openings of the first introduction passage 25 and the first drain passage 27 of the main valve block 1 with the plugs 80, and connecting the pilot pump 90 to the first primary pressure passage 26, the discharge pressure of the pilot pump 90 can be guided to the solenoid proportional pressure reducing valve 7 as a primary pilot pressure. Therefore, the main valve block 1 can be made common regardless of the presence or absence of the pilot pump 90.
  • In the fluid pressure control device 100, even when the pressure of the pilot oil guided to the primary pressure generating valve 30 increases, after the communication between the intra-spool passage 53 and the second introduction passage 35 is blocked in the primary pressure generating valve 30, the intra-spool passage 53 communicates with the second valve accommodation hole 42, and the pressure of the pilot oil in the intra-spool passage 53 decreases. Accordingly, the primary pilot pressure guided to the solenoid proportional pressure reducing valve 7 through the second primary pressure passage 26 can be kept constant regardless of a magnitude of the pressure of a pilot fluid guided through the second introduction passage 35.
  • Next, a modification of the present embodiment will be described. The following modification is also within the scope of the present invention, and it is also possible to combine the following modification and the configurations of the above embodiment.
    • <Modification>
  • In the above-described embodiment, the spool 50 has the main body 51 and is formed to have a uniform outer diameter. Alternatively, as shown in FIG. 7, the spool 50 may further include, in addition to the main body 51, a large-diameter portion 58 having a larger diameter than the main body 51. The large-diameter portion 58 is accommodated in the first sub-accommodation hole 41b. The first sub-accommodation hole 41b is divided, by the large-diameter portion 58, into a primary pressure chamber 39 communicating with the second primary pressure passage 26 and a damper chamber 40 communicating with the primary pressure chamber 39. The damper chamber 40 is expanded and contracted by the large-diameter portion 58 in accordance with movement of the spool 50. The damper chamber 40 is provided on a second valve accommodation hole 42 side (the right side in FIG. 7) in the first sub-accommodation hole 41b.
  • The large-diameter portion 58 is formed at a position where the large-diameter portion 58 does not come into contact with an inner wall 40a of the damper chamber 40 until the intra-spool passage 53 and the second drain passage 37 communicate with each other through the second valve accommodation hole 42 as shown in FIG. 5 when the pressure of the pilot oil guided to the primary pressure generating valve 30 increases. Specifically, when the end 50a of the spool 50 is seated on the first plug 61, a distance between the large-diameter portion 58 and the inner wall 40a is larger than a distance between the second throttle 55 and the second valve accommodation hole 42. The large-diameter portion 58 is formed so that the damper chamber 40 does not directly communicate with a second primary pressure passage 36 in a state where the end 50a of the spool 50 is seated on the first plug 61.
  • An outer diameter of the large-diameter portion 58 is slightly smaller than an inner diameter of the first sub-accommodation hole 41b. Therefore, a gap 59 is formed between an outer peripheral surface of the large-diameter portion 58 and an inner peripheral surface of the first sub-accommodation hole 41b. Since the damper chamber 40 communicates with the primary pressure chamber 39 through the gap 59, a pilot fluid is supplied to and discharged from the damper chamber 40 in accordance with movement of the spool 50.
  • Specifically, first, when the pilot fluid is guided to the intra-spool passage 53 through the second introduction passage 35 during standby of the fluid pressure control device 100, the pilot fluid is supplied from the primary pressure chamber 39 to the damper chamber 40 through the gap 59. When the fluid pressure control device 100 operates and the pressure of the second introduction passage 35 increases, the spool 50 moves to the right side in FIG. 7 against the biasing force of the spring 60. At this time, the pilot fluid in the damper chamber 40 is discharged to the primary pressure chamber 39 through the gap 59. When the second throttle 55 communicates with the second valve accommodation hole 42 and the pressure in the intra-spool passage 53 and the second introduction passage 35 decreases, the spool 50 moves to the left side in FIG. 7 by the biasing force of the spring 60, and at this time, the pilot fluid is supplied from the primary pressure chamber 39 to the damper chamber 40 through the gap 59.
  • As described above, in the present modification, the damper chamber 40 is defined by the large-diameter portion 58, and when the pressure in the second introduction passage 35 increases, the spool 50 moves while discharging the pilot fluid in the damper chamber 40 to the primary pressure chamber 39. Therefore, an amount of movement of the spool 50 is reduced as compared with a case where the spool 50 does not have the large-diameter portion 58. Accordingly, even when the pressure in the second introduction passage 35 rapidly increases, the rapid movement of the spool 50 is limited, and an opening area of the intra-spool passage 53 (second throttle 55) opening to the second valve accommodation hole 42 does not rapidly increase. Therefore, the pressure in the second primary pressure passage 36 is prevented from decreasing more than necessary, and the occurrence of hunting of the spool 50 can be prevented.
  • In the present modification, the primary pressure chamber 39 is open to an outer surface of the sub-valve block 2, and at the time of assembly, the spool 50 is attached from the opening, and the large-diameter portion 58 is accommodated in the first sub-accommodation hole 41b. In the present modification, in the intra-spool passage 53, the second introduction passage 35 and the second primary pressure passage 36 communicate with each other through a third throttle 56 provided on an end 50a side of the first throttle 54. Accordingly, the pressure loss is smaller than in the case where the second introduction passage 35 and the second primary pressure passage 36 communicate with each other through the groove 50b (see FIGS. 3 to 5).
  • The configurations, functions, and effects of the embodiment of the present invention configured as described above will be collectively described.
  • The fluid pressure control device 100 is configured to control the hydraulic cylinder 6 as an actuator driven by a working fluid discharged from the hydraulic pump 5 as a pump, and the fluid pressure control device 100 includes the control valve 10 that controls a flow of the working fluid to be supplied to and discharged from the hydraulic cylinder 6, the solenoid proportional pressure reducing valve 7 as a solenoid valve that generates pilot pressure for controlling the control valve 10, the main valve block 1 that is provided with the control valve 10 and the solenoid proportional pressure reducing valve 7, and the sub-valve block 2 that is detachably provided in the main valve block 1. The main valve block 1 includes the supply passage 20 that supplies the working fluid discharged from the hydraulic pump 5, the first introduction passage 25 that branches from the upstream side of the control valve 10 in the supply passage 20 and is capable of guiding a part of the fluid discharged from the hydraulic pump 5 as the pilot fluid to the sub-valve block 2, the first primary pressure passage 26 that guides the primary pilot pressure from the sub-valve block 2 or the pilot pump 90 to the solenoid proportional pressure reducing valve 7, and the first drain passage 27 that is capable of discharging the drain fluid from the sub-valve block 2 to the tank 4. The first introduction passage 25, the first primary pressure passage 26, and the first drain passage 27 are formed to open to the outer surface 1a of the main valve block 1, and in the sub valve block 2, openings 2a, 2b, and 2c that are capable of respectively communicating with the first introduction passage 25, the first primary pressure passage 26, and the first drain passage 27 are formed in the outer surface 2d, and the primary pressure generating valve 30 that is capable of generating a primary pilot pressure by reducing a pressure of a pilot fluid guided through the first introduction passage 25 and guiding the primary pilot pressure to the first primary pressure passage 26 is provided.
  • In this configuration, when the sub-valve block 2 is attached to the main valve block 1, a part of the working fluid discharged from the hydraulic pump 5 is guided to the sub-valve block 2 through the first introduction passage 25 as the pilot fluid, and the primary pilot pressure generated by the primary pressure generating valve 30 of the sub-valve block 2 is guided to the main valve block 1 through the first primary pressure passage 26. Thus, in the fluid pressure control device 100, the primary pressure generating valve 30 is provided not in the main valve block 1 but in the sub-valve block 2. Therefore, an oil passage of the main valve block 1 is simplified, and an increase in size of the main valve block 1 can be reduced. On the other hand, by removing the sub-valve block 2 from the main valve block 1, blocking the openings of the first introduction passage 25 and the first drain passage 27 of the main valve block 1 with plugs or the like, and connecting the pilot pump 90 to the first primary pressure passage 26, the discharge pressure of the pilot pump 90 can be guided to the solenoid proportional pressure reducing valve 7 as a primary pilot pressure. Therefore, the main valve block 1 can be made common regardless of the presence or absence of the pilot pump 90.
  • Further, in the fluid pressure control device 100, the primary pressure generating valve 30 includes the second introduction passage 35 formed in the sub-valve block 2 and capable of communicating with the first introduction passage 25 through the opening 2a, the second primary pressure passage 36 formed in the sub-valve block 2 and capable of communicating with the first primary pressure passage 26 through the opening 2b, the first valve accommodation hole 41 through which the second introduction passage 35 and the second primary pressure passage 36 communicate with each other, and the spool 50 serving as a valve body that is partially accommodated in the first valve accommodation hole 41 and controls the flow of a fluid from the second introduction passage 35 to the second primary pressure passage 36. The spool 50 includes the intra-spool passage 53 serving as an intra-valve passage formed inside the spool 50 and allowing the second introduction passage 35 and the second primary pressure passage 36 to communicate with each other, and the first restrictor 54 serving as a throttle provided in the intra-spool passage 53 and configured to apply resistance to the pilot oil passing therethrough.
  • In this configuration, the fluid discharged from the hydraulic pump 5 is further reduced in pressure by the first throttle 54 provided in the intra-spool passage 53, and the primary pilot pressure guided to the solenoid proportional pressure reducing valve 7 can be generated.
  • In the fluid pressure control device 100, the primary pressure generating valve 30 further includes the second drain passage 37 that is formed in the sub-valve block 2 and is capable of communicating with the first drain passage 27 through the opening 2c, the second valve accommodation hole 42 that communicates with the first valve accommodation hole 41 and accommodates a part of the spool 50, and the spring 60 serving as a biasing member that is accommodated in the second valve accommodation hole 42 and biases the spool 50 toward the first valve accommodation hole 41. The spool 50 is moved by a balance between a pressure of a fluid downstream of the first throttle 54 in the intra-spool passage 53 and the biasing force of the spring 60, and the second primary pressure passage 36 communicates with the second introduction passage 35 or the second drain passage 37 through the intra-spool passage 53 in accordance with the movement of the spool 50.
  • In this configuration, the primary pilot pressure guided to the solenoid proportional pressure reducing valve 7 through the second primary pressure passage 36 can be kept constant regardless of the magnitude of the pressure of the pilot fluid guided through the second introduction passage 35.
  • Further, in the fluid pressure control device 100, the spool 50 further includes the main body 51 and the large-diameter portion 58 formed to have a larger diameter than the main body 51. The first valve accommodation hole 41 includes the main accommodating hole 41a in which the main body 51 slides, and the first sub-accommodation hole 41b having a larger inner diameter than the main accommodation hole 41a and serving as a sub-accommodation hole in which the large-diameter portion 58 is accommodated. The first sub-accommodation hole 41b is divided into the primary pressure chamber 39 communicating with the second primary pressure passage 36 and the damper chamber 40 communicating with the primary pressure chamber 39 and expanded and contracted by the large-diameter portion 58 in accordance with movement of the spool 50.
  • In this configuration, an amount of movement of the spool 50 is reduced as compared with the case where the spool 50 does not have the large-diameter portion 58. Accordingly, even when the pressure in the second introduction passage 35 rapidly increases, the rapid movement of the spool 50 is limited, the pressure in the second primary pressure passage 36 is prevented from decreasing more than necessary, and the occurrence of hunting of the spool 50 can be prevented.
  • Embodiments of the present invention were described above, but the above embodiments are merely examples of applications of the present invention, and the technical scope of the present invention is not limited to the specific constitutions of the above embodiments.
  • With respect to the above description, the contents of application No. 2022-191551, with a filing date of November 30, 2022 in Japan, are incorporated herein by reference.

Claims (4)

  1. A fluid pressure control device for controlling an actuator driven by a working fluid discharged from a pump, the fluid pressure control device comprising:
    a control valve configured to control a flow of the working fluid to be supplied to and discharged from the actuator;
    a solenoid valve configured to generate a pilot pressure for controlling the control valve;
    a main valve block provided with the control valve and the solenoid valve; and
    a sub-valve block detachably attached to the main valve block, wherein
    the main valve block includes,
    a supply passage configured to supply the working fluid discharged from the pump,
    a first introduction passage branching from an upstream side of the control valve in the supply passage and capable of guiding a part of the fluid discharged from the pump as a pilot fluid to the sub-valve block,
    a first primary pressure passage for guiding a primary pilot pressure from the sub-valve block or a pilot pump to the solenoid valve, and
    a first drain passage capable of discharging a drain fluid from the sub-valve block to a tank,
    the first introduction passage, the first primary pressure passage, and the first drain passage are formed to open to an outer surface of the main valve block, and
    in the sub-valve block, openings capable of respectively communicating with the first introduction passage, the first primary pressure passage, and the first drain passage are formed in an outer surface, and a primary pressure generating valve capable of generating a primary pilot pressure by reducing a pressure of the pilot fluid guided through the first introduction passage and guiding the primary pilot pressure to the first primary pressure passage is provided.
  2. The fluid pressure control device according to claim 1, wherein
    the primary pressure generating valve includes
    a second introduction passage formed in the sub-valve block and capable of communicating with the first introduction passage through the opening,
    a second primary pressure passage formed in the sub-valve block and capable of communicating with the first primary pressure passage through the opening,
    a first valve accommodation hole through which the second introduction passage and the second primary pressure passage communicate with each other, and
    a valve body partially accommodated in the first valve accommodation hole and configured to control a flow of a fluid from the second introduction passage to the second primary pressure passage, and
    the valve body includes
    an intra-valve passage formed in the valve body and allowing the second introduction passage and the second primary pressure passage to communicate with each other, and
    a throttle provided in the intra-valve passage and configured to apply resistance to the fluid passing through the intra-valve passage.
  3. The fluid pressure control device according to claim 2, wherein
    the primary pressure generating valve further includes
    a second drain passage formed in the sub-valve block and capable of communicating with the first drain passage through the opening,
    a second valve accommodation hole communicating with the first valve accommodation hole and configured to accommodate a part of the valve body, and
    a biasing member accommodated in the second valve accommodation hole and configured to bias the valve body toward the first valve accommodation hole,
    the valve body is moved by a balance between a pressure of a fluid downstream of the throttle in the intra-valve passage and a biasing force of the biasing member, and
    the second primary pressure passage communicates with the second introduction passage or the second drain passage through the intra-valve passage in accordance with movement of the valve body.
  4. The fluid pressure control device according to claim 2, wherein
    the valve body further includes
    a main body, and
    a large-diameter portion formed to have a larger diameter than the main body,
    the first valve accommodation hole includes
    a main accommodation hole in which the main body slides, and
    a sub-accommodation hole which has a larger inner diameter than the main accommodation hole and in which the large-diameter portion is accommodated, and
    the sub-accommodation hole is divided into a primary pressure chamber communicating with the second primary pressure passage and a damper chamber communicating with the primary pressure chamber and expanded and contracted by the large-diameter portion in accordance with movement of the valve body.
EP23897304.4A 2022-11-30 2023-10-20 Fluid pressure control device Pending EP4628736A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2022191551 2022-11-30
PCT/JP2023/038041 WO2024116647A1 (en) 2022-11-30 2023-10-20 Fluid pressure control device

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EP4628736A1 true EP4628736A1 (en) 2025-10-08

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EP23897304.4A Pending EP4628736A1 (en) 2022-11-30 2023-10-20 Fluid pressure control device

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EP (1) EP4628736A1 (en)
JP (1) JP7805484B2 (en)
CN (1) CN120187957A (en)
WO (1) WO2024116647A1 (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2019094973A (en) 2017-11-22 2019-06-20 キャタピラー エス エー アール エル Hydraulic control circuit of construction machine
JP2022191551A (en) 2021-06-16 2022-12-28 サミー株式会社 Pachinko game machine

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004084828A (en) * 2002-08-27 2004-03-18 Komatsu Ltd Electromagnetic proportional control valve unit with switching valve
EP2876306B1 (en) 2012-07-19 2018-11-07 Volvo Construction Equipment AB Flow control valve for construction machinery
JP2020034113A (en) * 2018-08-30 2020-03-05 Ｋｙｂ株式会社 Fluid pressure control device

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2019094973A (en) 2017-11-22 2019-06-20 キャタピラー エス エー アール エル Hydraulic control circuit of construction machine
JP2022191551A (en) 2021-06-16 2022-12-28 サミー株式会社 Pachinko game machine

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of WO2024116647A1

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JP7805484B2 (en) 2026-01-23
CN120187957A (en) 2025-06-20
WO2024116647A1 (en) 2024-06-06

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