Title:
CONTROL UNIT FOR HYDRAULIC SYSTEM
Document Type and Number:
Japanese Patent JPS57195955
Kind Code:
A
Abstract:
PURPOSE:To prevent a lag in working of a variable-capacity hydraulic pump by controlling a pilot pressure signal led to a pressure receiving portion of a servo- valve according to pressure of each main circuit on discharge side and suction side in a control unit for a hydraulic shovel. CONSTITUTION:A pilot pressure signal is output from a pilot valve 11A by operation of an operation lever 10A. If each pressure of main circuits A, B is zero, a first control valve 15 is located at a neutral position 15C, so that the pilot pressure signal is led to a first pressure receiving portion 6a of a servo- valve 6 so as to switch the servo-valve 6 over to a switching position 6A. Control oil from a control hydraulic source 9 passes through the valve 6 into a left oil chamber 5A of a controlling actuator 5 so as to move a piston to the right, which causes a squeezing capacity changing mechanism 4 to move from a neutral position in such a manner as to discharge toward the main circuit A, so that a variable-capacity hydraulic pump 1 discharges pressure oil to the main circuit A.
Inventors:
TANAKA YASUO
ONO KOUZOU
IZUMI EIKI
SHIMOTORI MASAHIKO
YOSHIDA KUNIHIKO
GOTOU YASUHARU
TANAKA SOUTAROU
AOYANAGI YUKIO
ONO KOUZOU
IZUMI EIKI
SHIMOTORI MASAHIKO
YOSHIDA KUNIHIKO
GOTOU YASUHARU
TANAKA SOUTAROU
AOYANAGI YUKIO
Application Number:
JP7865781A
Publication Date:
December 01, 1982
Filing Date:
May 26, 1981
Export Citation:
Assignee:
HITACHI CONSTRUCTION MACHINERY
International Classes:
E02F9/22; F16H61/42; F16H61/433; (IPC1-7): E02F9/22