JPS57178043A - Hydraulic circuit of construction equipment - Google Patents

Hydraulic circuit of construction equipment

Info

Publication number
JPS57178043A
JPS57178043A JP6146381A JP6146381A JPS57178043A JP S57178043 A JPS57178043 A JP S57178043A JP 6146381 A JP6146381 A JP 6146381A JP 6146381 A JP6146381 A JP 6146381A JP S57178043 A JPS57178043 A JP S57178043A
Authority
JP
Japan
Prior art keywords
pilot
valve
valves
opening
controlled
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.)
Granted
Application number
JP6146381A
Other languages
Japanese (ja)
Other versions
JPH0257171B2 (en
Inventor
Kunihiko Yoshida
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 JP6146381A priority Critical patent/JPS57178043A/en
Publication of JPS57178043A publication Critical patent/JPS57178043A/en
Publication of JPH0257171B2 publication Critical patent/JPH0257171B2/ja
Granted legal-status Critical Current

Links

Classifications

    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02FDREDGING; SOIL-SHIFTING
    • E02F9/00Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20Drives; Control devices
    • E02F9/22Hydraulic or pneumatic drives
    • E02F9/2221Control of flow rate; Load sensing arrangements
    • E02F9/2232Control of flow rate; Load sensing arrangements using one or more variable displacement pumps
    • EFIXED CONSTRUCTIONS
    • E02HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02FDREDGING; SOIL-SHIFTING
    • E02F9/00Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20Drives; Control devices
    • E02F9/22Hydraulic or pneumatic drives
    • E02F9/2278Hydraulic circuits
    • E02F9/2296Systems with a variable displacement pump

Landscapes

  • Engineering & Computer Science (AREA)
  • Mining & Mineral Resources (AREA)
  • Civil Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structural Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Operation Control Of Excavators (AREA)

Abstract

PURPOSE:To eliminate the need for a bypass of a switch valve and to improve a control ability of a working cylinder, by a method wherein an opening and shutting valve for controlling a discharge amount of a pump is located between a hydraulic pump and a tank, and is controlled by a pilot valve for regulating a switch valve which drives the working cylinder. CONSTITUTION:Discharge amounts of variable capacity type hydraulic pumps 2a and 2b are controlled by pilot valves 41 and 42 for regulating pilot system direction switching valve 36 and 37 which drives a working cylinder. A pilot type opening and shutting valve 40 is situated in the middle of a line, with which discharge sides of the variable capacity type pumps 2a and 2b are coupled to a tank, it is controlled by pilot valves 41 and 42, and no bypass oil path is formed at the switching valves 36 nd 37. At a time when the pilot valves 41 and 42 are in a non-operating condition, the switch valves 36 and 37 are brought to a neutral, the opening and shutting valve is open, and the discharge amount of the hydraulic pump 2a is minimum. With the pilot valve 41 operated, the opening and shutting valve 40 is brought to a closing state, and the discharge amount of the hydraulic pump 2a varies with pilot pressure.
JP6146381A 1981-04-24 1981-04-24 Hydraulic circuit of construction equipment Granted JPS57178043A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP6146381A JPS57178043A (en) 1981-04-24 1981-04-24 Hydraulic circuit of construction equipment

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP6146381A JPS57178043A (en) 1981-04-24 1981-04-24 Hydraulic circuit of construction equipment

Publications (2)

Publication Number Publication Date
JPS57178043A true JPS57178043A (en) 1982-11-02
JPH0257171B2 JPH0257171B2 (en) 1990-12-04

Family

ID=13171749

Family Applications (1)

Application Number Title Priority Date Filing Date
JP6146381A Granted JPS57178043A (en) 1981-04-24 1981-04-24 Hydraulic circuit of construction equipment

Country Status (1)

Country Link
JP (1) JPS57178043A (en)

Also Published As

Publication number Publication date
JPH0257171B2 (en) 1990-12-04

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