JPS579302A - Unload valve - Google Patents

Unload valve

Info

Publication number
JPS579302A
JPS579302A JP8139480A JP8139480A JPS579302A JP S579302 A JPS579302 A JP S579302A JP 8139480 A JP8139480 A JP 8139480A JP 8139480 A JP8139480 A JP 8139480A JP S579302 A JPS579302 A JP S579302A
Authority
JP
Japan
Prior art keywords
pressure
main
oil
discharge
pump
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
JP8139480A
Other languages
Japanese (ja)
Inventor
Toichi Hirata
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.)
Hitachi Construction Machinery Co Ltd
Original Assignee
Hitachi Construction Machinery Co Ltd
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 Hitachi Construction Machinery Co Ltd filed Critical Hitachi Construction Machinery Co Ltd
Priority to JP8139480A priority Critical patent/JPS579302A/en
Publication of JPS579302A publication Critical patent/JPS579302A/en
Pending legal-status Critical Current

Links

Landscapes

  • Operation Control Of Excavators (AREA)
  • Fluid-Pressure Circuits (AREA)

Abstract

PURPOSE: To effectively utilize the output of a prime mover by controlling the pressure-receiving area of two pilot pressure receiving members to make it a value proportional to the total discharge amount of the main pumps in the unload valve of an oil-pressure circuit with plural pumps.
CONSTITUTION: In an oil-presssure circuit having the main pumps 2 and 3 and an accelerating pump 4 whose oil pressure is jointed with the oil pressure of the main pump 3, the discharge pressures of the main pumps 2 and 3 as pilot pressures are acted on an unload valve 6, and the accelerating pump 4 is unloaded in the position II. Then, in the unload valve 6, the values of the pressure-receiving areas A and B of the pilot pressure-receiving members 15 and 16 are controlled so as to proportionate to the total discharge amounts D1 and D1+D2 (where D1 is the discharge amounts of the main pumps 2 and 3 and D2 is the discharge amount of the accelerating pump 4. And, when the formula D1Sp1+(D1+D2)Sp1≥F where S is a constant, p1 is the discharge pressure of the main pump 2, and F is the pushing force of a spring 14, is met, the valve 6 is switched to the position II.
COPYRIGHT: (C)1982,JPO&Japio
JP8139480A 1980-06-18 1980-06-18 Unload valve Pending JPS579302A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP8139480A JPS579302A (en) 1980-06-18 1980-06-18 Unload valve

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP8139480A JPS579302A (en) 1980-06-18 1980-06-18 Unload valve

Publications (1)

Publication Number Publication Date
JPS579302A true JPS579302A (en) 1982-01-18

Family

ID=13745080

Family Applications (1)

Application Number Title Priority Date Filing Date
JP8139480A Pending JPS579302A (en) 1980-06-18 1980-06-18 Unload valve

Country Status (1)

Country Link
JP (1) JPS579302A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58224561A (en) * 1982-06-21 1983-12-26 Sharp Corp Switching type constant-voltage circuit
JPS61131139U (en) * 1985-02-05 1986-08-16
EP3943756A4 (en) * 2019-03-19 2022-11-30 Yanmar Power Technology Co., Ltd. Hydraulic circuit for construction machine, and hydraulic circuit

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58224561A (en) * 1982-06-21 1983-12-26 Sharp Corp Switching type constant-voltage circuit
JPS61131139U (en) * 1985-02-05 1986-08-16
EP3943756A4 (en) * 2019-03-19 2022-11-30 Yanmar Power Technology Co., Ltd. Hydraulic circuit for construction machine, and hydraulic circuit

Similar Documents

Publication Publication Date Title
ES462925A1 (en) Hydraulic system for supplying hydraulic fluid to a hydraulically operated device alternately at pressures of different value
JPS579302A (en) Unload valve
JPS5587865A (en) Control circuit of variable capacity pump
GB1508948A (en) Piston pump assembly utilizing load pressure control
JPS5569782A (en) Output-power controller for pumps
JPS5794103A (en) Hydraulic circuit
JPS5311306A (en) Pump unit
JPS56143803A (en) Fluid controller
JPS54108002A (en) Input power controlling system for hydraulic pump
JPS5773203A (en) Oil pressure circuit
JPS56143857A (en) Stepless hydraulic transmission device
JPS5718485A (en) Liquid pressurizing device of variable volume type
JPS53140479A (en) Hydraulic pressure controller
JPS5765467A (en) Relief valve
JPS5632088A (en) Input torque controlling system for variable displacement pump
JPS57140583A (en) Controller for power of hydraulic equipment
JPS56118580A (en) Control circuit for variable capacity type pump
JPS5776358A (en) Automatic speed change valve
JPS5632087A (en) Input torque controlling system for variable displacement pump
JPS5311302A (en) Control circuit of plural hydraulic pump and input controller for control circuit
JPS5284377A (en) Coaxial boost cylinder oil pressure circuit
JPS57210188A (en) Total horsepower control method for a multitude of oil hydraulic pumps
JPS56159584A (en) Oil pressure control circuit for construction machine
JPS5758739A (en) Construction machinery such as power shovel
JPS5297073A (en) Speed controller in oil pressure transmitter