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
  • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
  • F15B11/08—Servomotor systems without provision for follow-up action; Circuits therefor with only one servomotor

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

Applications Claiming Priority (2)

Publications (1)

Family

ID=91323643

Family Applications (1)

Country Status (4)

Citations (2)

Family Cites Families (3)

• 2023
  • 2023-10-20 JP JP2024561249A patent/JPWO2024116647A1/ja active Pending
  • 2023-10-20 EP EP23897304.4A patent/EP4628736A1/en active Pending
  • 2023-10-20 WO PCT/JP2023/038041 patent/WO2024116647A1/ja not_active Ceased
  • 2023-10-20 CN CN202380078653.9A patent/CN120187957A/zh active Pending

Patent Citations (2)

Non-Patent Citations (1)

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