Title:
【発明の名称】油圧駆動装置及び方向切換弁
Document Type and Number:
Japanese Patent JP2744846
Kind Code:
B2
Abstract:
Each of direction change-over valves (5, 6) respectively provided between a hydraulic supply system (50) and a plurality of actuators (3, 4) comprises: a pump port (9); a pressure chamber (10); a feeder path (11); actuator ports (12a, 12b); a tank port (13); first variable throttles (15a, 15b) of a meter-in system, which are provided between the pump port and the pressure chamber; and a pressure compensation valve (16) provided between the pressure chamber and the feeder path, one of opposing ends of which receives pressure from the pressure chamber and the other end of which receives the maximum of load pressures of the plurality of actuators. The hydraulic supply system comprises: a hydraulic pump (1); and a pump flowrate control device (2) for controlling a discharge flowrate of the hydraulic pump in such a manner that discharge pressure of the hydraulic pump is higher by a predetermined value than the maximum of load sensing pressures obtained from load pressures of the plurality of actuators. At least one of the direction change-over valves further comprises: a bleed path (21) for connecting the feeder path (11) and the tank port (13) to each other; and second variable throttles (22a, 22b) provided in this bleed path and interlocked with the first variable throttles of the meter-in system. With this arrangement, an abrupt action of the actuators for driving an inertial member is prevented and vibrations of the circuit are controlled even when one of a pump discharge flowrate and a load pressure is fluctuated.
Inventors:
Toichi Hirata
Genroku Sugiyama
Genroku Sugiyama
Application Number:
JP50053992A
Publication Date:
April 28, 1998
Filing Date:
November 26, 1991
Export Citation:
Assignee:
Hitachi Construction Machinery Co., Ltd.
International Classes:
E02F9/22; F15B11/00; F15B11/05; F15B11/16; F15B13/04; F15B13/042; F16K11/07; (IPC1-7): F15B11/00; E02F9/22; F15B11/05; F15B11/16; F15B13/042; F16K11/07
Domestic Patent References:
| JP57116965A | ||||
| JP6032041B2 |
Other References:
【文献】米国特許4939023(US,A)
【文献】英国公開2195745(GB,A)
【文献】西独国特許出願公開2906670(DE,A)
【文献】英国公開2195745(GB,A)
【文献】西独国特許出願公開2906670(DE,A)
Attorney, Agent or Firm:
Kasuga