JPS61180256U

JPS61180256U -

Info

Publication number: JPS61180256U
Application number: JP6107385U
Authority: JP
Priority date: 1985-04-25
Filing date: 1985-04-25
Publication date: 1986-11-10

Description

[Brief explanation of the drawing]

第１図、第２図は本考案の実施例を示す回路図
、第３図、第４図、第５図は従来例を示す回路図
である。１ａ，１ｂ，１ｃは油圧ポンプ、３はドレン回
路、５ａ，５ｂ，５ｃはポンプデリバリ回路、６
はインラインフイルタ、７はリリーフ弁、８は圧
力スイツチ、１０は下流側回路、１１は逆止弁、
１２はリターンフイルタ。 1 and 2 are circuit diagrams showing an embodiment of the present invention, and FIGS. 3, 4, and 5 are circuit diagrams showing a conventional example. 1a, 1b, 1c are hydraulic pumps, 3 is a drain circuit, 5a, 5b, 5c is a pump delivery circuit, 6
is an in-line filter, 7 is a relief valve, 8 is a pressure switch, 10 is a downstream circuit, 11 is a check valve,
12 is a return filter.

Claims

[Scope of utility model registration request]

Hydraulic pumps 1a, 1b, 1c, valves that selectively supply hydraulic pressure from the hydraulic pumps 1a, 1b, 1c to actuators, and a drain circuit 3 that drains drain oil from the actuators to a tank via the valves. In the hydraulic circuit of a construction machine, an in-line filter 6 is installed in pump delivery circuits 5a, 5b, 5c between hydraulic pumps 1a, 1b, 1c and valves, and the upstream side of this in-line filter 6 is connected to a relief valve 7. , and the drain circuit 3 is provided with a check valve 11 upstream from the connection point with the downstream circuit 10 of the relief valve 7 and a return filter 12 downstream. Furthermore, a pressure switch 8 which is activated by the pressure difference between the sides of the in-line filter 6 in the flow direction is connected to the pump delivery circuits 5a, 5b, and 5c, and this pressure switch 8 is interposed in the warning circuit. Features hydraulic circuits for construction machinery.