Title:
CONSTANT PRESSURE CONTROLLED LIQUID HYDRAULIC DRIVEN DEVICE
Document Type and Number:
Japanese Patent JP3545111
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To obtain sufficient holding force (braking force) at the time when a command means indicates neutral in a constant pressure controlled liquid hydraulic driven device.
SOLUTION: A first cam 27 shifts a directional control valve 20 to neutral at the time when an operation lever 9 is neutral and in a braking range 9a, 9b and when shifted to a drive range 9c, 9d the directional control valve 20 is shifted to a position (a) or a position (b) according to the operation direction. A second cam 28 controls the inclination of an oil hydraulic motor 4 to the maximum when the operation lever 9 is neutral, and when it is in the braking range 9a, 9b the inclination of the oil hydraulic motor 4 is controlled according to the operation, when it is in the drive range 9c, 9d the inclination of the oil hydraulic motor is controlled according to the operation signal. Check valves 23, 24 allowing flow only to a high pressure conduit 7 from a first conduit 21 and a second conduit 22 and check valves 25, 26 preventing the generation of negative pressure of the first conduit 21 and the second conduit 22 are provided.
Inventors:
Akira Hibi
Morio Oka
Morio Oka
Application Number:
JP24964795A
Publication Date:
July 21, 2004
Filing Date:
September 27, 1995
Export Citation:
Assignee:
Hitachi Construction Machinery Co., Ltd.
International Classes:
F15B9/14; F15B11/028; F15B11/08; F15B13/042; (IPC1-7): F15B11/08; F15B11/028
Domestic Patent References:
| JP4370403A | ||||
| JP7139510A | ||||
| JP478302A |
Foreign References:
| WO1993018308A1 |
Attorney, Agent or Firm:
Kasuga Toshiaki
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