JPS5776304A - Hydraulic circuit for construction machinery - Google Patents

Hydraulic circuit for construction machinery

Info

Publication number
JPS5776304A
JPS5776304A JP55151425A JP15142580A JPS5776304A JP S5776304 A JPS5776304 A JP S5776304A JP 55151425 A JP55151425 A JP 55151425A JP 15142580 A JP15142580 A JP 15142580A JP S5776304 A JPS5776304 A JP S5776304A
Authority
JP
Japan
Prior art keywords
pressure
flow rate
bleed
pump
passage
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
JP55151425A
Other languages
Japanese (ja)
Inventor
Norihei Yamaji
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.)
NIPPON SEIKOSHO KK
Japan Steel Works Ltd
Original Assignee
NIPPON SEIKOSHO KK
Japan Steel Works 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 NIPPON SEIKOSHO KK, Japan Steel Works Ltd filed Critical NIPPON SEIKOSHO KK
Priority to JP55151425A priority Critical patent/JPS5776304A/en
Publication of JPS5776304A publication Critical patent/JPS5776304A/en
Pending legal-status Critical Current

Links

Landscapes

  • Fluid-Pressure Circuits (AREA)
  • Control Of Positive-Displacement Pumps (AREA)

Abstract

PURPOSE: To control the flow rate of a main pump according to the variation of its bleed-off flow rate in a power-saving type hydraulic circuit by connecting a discharging pipe of an auxiliary pump to a center-by-pass passage of change- over valves and thereby producing a bleed-off flow rate which is regulated by the passage pressure.
CONSTITUTION: With change-over valves 3 all in neutral position, the discharge flow from an auxiliary pump returns to a tank 7. At this time, the pressure in a discharge pipe passage 13 is low and the set-pressure of a bleed-off valve 5 becomes the lowest for unloading the flow from a main pump 1. The unloaded flow produces pressure after being throttled by a throttle 6, and this pressure reduces the discharge flow rate from the pump 1. If the change-over valves are switched, a by-pass passage 14 is throttled depending on a stroke of a spool, whereby the pressure in the discharge pipe passage 13 increases and the set- pressure of the bleed-off valve 5 is subsequently increases. Accordingly, the bleed-off flow rate for the pump 1 decreases and the pressure produced by a throttle 6 lowers, and the discharge flow rate from the pump 1 increases.
COPYRIGHT: (C)1982,JPO&Japio
JP55151425A 1980-10-30 1980-10-30 Hydraulic circuit for construction machinery Pending JPS5776304A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP55151425A JPS5776304A (en) 1980-10-30 1980-10-30 Hydraulic circuit for construction machinery

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP55151425A JPS5776304A (en) 1980-10-30 1980-10-30 Hydraulic circuit for construction machinery

Publications (1)

Publication Number Publication Date
JPS5776304A true JPS5776304A (en) 1982-05-13

Family

ID=15518334

Family Applications (1)

Application Number Title Priority Date Filing Date
JP55151425A Pending JPS5776304A (en) 1980-10-30 1980-10-30 Hydraulic circuit for construction machinery

Country Status (1)

Country Link
JP (1) JPS5776304A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6155090A (en) * 1984-08-27 1986-03-19 石川島播磨重工業株式会社 Drive for grab bucket
JPS61252902A (en) * 1985-05-02 1986-11-10 ダンフオス　アクチエセルスカベト Controller for at least one hydraulic operating actuator
JPS6216804U (en) * 1985-07-15 1987-01-31
JPWO2018164263A1 (en) * 2017-03-10 2020-01-23 住友建機株式会社 Excavator

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6155090A (en) * 1984-08-27 1986-03-19 石川島播磨重工業株式会社 Drive for grab bucket
JPS61252902A (en) * 1985-05-02 1986-11-10 ダンフオス　アクチエセルスカベト Controller for at least one hydraulic operating actuator
JPS6216804U (en) * 1985-07-15 1987-01-31
JPH0542243Y2 (en) * 1985-07-15 1993-10-25
JPWO2018164263A1 (en) * 2017-03-10 2020-01-23 住友建機株式会社 Excavator

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