DRIVING DEVICE FOR A HYDRAULIC MOTOR

Title:

DRIVING DEVICE FOR A HYDRAULIC MOTOR

Document Type and Number:

WIPO Patent Application WO/1996/030651

Kind Code:

A1

Abstract:

A driving device for a hydraulic motor comprising a directional control valve (21) for supplying pressure oil discharged from a hydraulic pump (20) to a first port (25) or a second port (26) of a hydraulic motor (24) and returning oil returning from the second port or the first port to a tank (27) and a pilot pressure supplying valve (40) for controlling the directional control valve (21) wherein the directional control valve is of a pilot pressure selection type in which the valve is positioned, respectively, at a neutral position A by means of springs (32, 33), at a first position B by virtue of a pressure to a first pressure receiving portion (34), and at a second position C by virtue of a pressure to a second pressure receiving portion (35), wherein when the directional control valve is at the neutral position, the discharged pressure oil is supplied to the first and second ports via check valves (36, 37), when at the first position, the discharged pressure oil is supplied to the first port, while pressure oil at the second port is discharged therefrom into the tank, and when at the second position, the discharged pressure oil is supplied to the second port, while pressure oil at the second port is discharged therefrom into the tank, wherein the pilot pressure supplying valve is positioned at a neutral position F by means of springs (50, 51), and is switched to a first position G and a second position H by first and second drive means (52, 53), respectively, so as to supply pilot pressure to the first and second pressure receiving portions, and wherein when the pilot pressure supplying valve is positioned at the neutral position, the first and second pressure receiving portions communicate with the tank, when at the first position, the first port communicates with the first pressure receiving portion, while the second pressure receiving portion communicates with the tank and when at the second position, the second port communicates with the second pressure receiving portion, while the first pressure receiving portion communicates with the tank.

Inventors:

HAYASHI SEITA (JP)
NUNOTANI SADAO (JP)
AKASAKA TOSIYUKI (JP)

Application Number:

PCT/JP1996/000764

Publication Date:

October 03, 1996

Filing Date:

March 22, 1996

Export Citation:

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Assignee:

KOMATSU MFG CO LTD (JP)
HAYASHI SEITA (JP)
NUNOTANI SADAO (JP)
AKASAKA TOSIYUKI (JP)

International Classes:

E02F9/12; F15B11/00; E02F9/22; F15B11/044; F15B11/05; F15B11/08; F15B13/04; (IPC1-7): F15B11/00; F15B11/08

Foreign References:

JPH0450507A	1992-02-19
JPH04133003U	1992-12-10
JPS5469676A	1979-06-04
JPS60260703A	1985-12-23

Other References: