JPH027387U

JPH027387U -

Info

Publication number: JPH027387U
Application number: JP8477688U
Authority: JP
Priority date: 1988-06-27
Filing date: 1988-06-27
Publication date: 1990-01-18

Description

[Brief explanation of the drawing]

第１図は本考案実施例のパイロツト機構の断面
図、第２図は第１図のパイロツト機構を採用した
ポンプシステムの略図、第３図は吐出量制御特性
を示すグラフである。１……油圧ポンプ、３……サーボシリンダ、８
……制御弁、１３……フイードバツクレバー、２
０……パイロツト機構、２１……パイロツトスプ
ール、４５……ピストン、４６……ストツパー、
４８……指令圧室、５５……ばね（付勢機構）、
６０……パイロツト圧室、６３……指令圧制御ラ
イン。 FIG. 1 is a sectional view of a pilot mechanism according to an embodiment of the present invention, FIG. 2 is a schematic diagram of a pump system employing the pilot mechanism of FIG. 1, and FIG. 3 is a graph showing discharge rate control characteristics. 1... Hydraulic pump, 3... Servo cylinder, 8
...Control valve, 13...Feedback lever, 2
0... Pilot mechanism, 21... Pilot spool, 45... Piston, 46... Stopper,
48... Command pressure chamber, 55... Spring (biasing mechanism),
60...Pilot pressure chamber, 63...Command pressure control line.

Claims

[Scope of utility model registration request]

A control valve is provided to control the hydraulic pressure of a servo cylinder for controlling the discharge amount, and a pilot spool of a pilot mechanism is connected to the control valve, and the control valve and the servo are connected so that the discharge amount control state of the servo cylinder corresponds to the position of the pilot spool. A piston is connected to the cylinder by a feedback lever, and the pilot mechanism includes a piston that determines the limit of movement of the pilot spool in one direction, and a piston that is movable in a predetermined section in a direction opposite to the one direction of the piston. A stopper for determining the movement limit of the stopper, a biasing mechanism for biasing the stopper in the above-mentioned one direction, and a command pressure chamber for biasing the stopper and the piston in the above-mentioned opposite direction. and a command pressure control line capable of selectively supplying and stopping the supply of the second hydraulic pressure is connected to the command pressure chamber,
A variable displacement hydraulic pump characterized in that only the piston is moved to the limit position in the opposite direction by the hydraulic pressure, and the piston and the stopper are moved to the limit position in the opposite direction by the second hydraulic pressure. flow control device.