JPH0354854U

JPH0354854U -

Info

Publication number: JPH0354854U
Application number: JP11357189U
Authority: JP
Priority date: 1989-09-29
Filing date: 1989-09-29
Publication date: 1991-05-27
Anticipated expiration: 2004-09-28
Also published as: JPH0637091Y2

Description

[Brief explanation of drawings]

第１図は本考案の土木・建設機械の油圧駆動装
置の一実施例を示す回路図、第２図はこの実施例
に備えられるレギユレータを示す説明図である。１，２……可変容量油圧ポンプ、３……コント
ロールバルブ、４……アクチユエータ（標準仕様
）、５……第１の方向切換弁、５ａ……第２の方
向切換弁、５ｃ……閉位置、７……別のアクチユ
エータ（追加のアクチユエータ）、８……第３の
方向切換弁、９……操作装置（パイロツトバルブ
）、１０……シヤトル弁、１１……２位置切換弁
、１２……減圧弁、１３……シヤトル弁、１３ａ
……管路、１４……タンク、１４ａ……絞り、１
５，１６，１６ａ，１６ｂ，１６ｃ，１７……管
路、２１……レギユレータ。 FIG. 1 is a circuit diagram showing an embodiment of the hydraulic drive system for civil engineering and construction machinery of the present invention, and FIG. 2 is an explanatory diagram showing a regulator provided in this embodiment. 1, 2... Variable displacement hydraulic pump, 3... Control valve, 4... Actuator (standard specification), 5... First directional switching valve, 5a... Second directional switching valve, 5c... Closed position , 7... Another actuator (additional actuator), 8... Third directional switching valve, 9... Operating device (pilot valve), 10... Shuttle valve, 11... 2-position switching valve, 12... Pressure reducing valve, 13...Shuttle valve, 13a
...Pipeline, 14...Tank, 14a...Aperture, 1
5, 16, 16a, 16b, 16c, 17...Pipeline, 21...Regulator.

Claims

[Scope of utility model registration request]

A variable displacement hydraulic pump, an actuator driven by pressure oil supplied from the variable displacement hydraulic pump, and a first directional control valve that controls the flow of the pressure oil supplied from the variable displacement hydraulic pump to the actuator. and a second directional control valve,
The actuator is driven in one direction by supplying pressure oil from the variable displacement hydraulic pump through both the first directional valve and the second directional valve, and the actuator is driven in the other direction. This is carried out by supplying pressure oil for the variable displacement hydraulic pump only through the second directional switching valve, and the first directional switching valve has an empty position in which it does not participate in driving the actuator in the other direction. The hydraulic drive device for construction machinery includes another actuator different from the actuator, a third directional control valve for controlling the drive of the other actuator, and one end connected to the variable displacement hydraulic pump and the first
a conduit connected to a conduit portion between the directional control valve and the third directional control valve, the other end being connected to the third directional control valve; an operating device for controlling the drive of the third directional control valve; a control means capable of changing the displacement of the variable displacement hydraulic pump in accordance with the operation of the operating device;
A switching means for switching the first directional control valve to an empty position in response to the operation of the operating device, and disabling the operation of the switching means when both the first directional control valve and the second directional control valve are switched. A hydraulic drive device for civil engineering and construction machinery, characterized in that the empty position is formed in a closed position to block the flow of pressure oil discharged from the variable displacement hydraulic pump.