To provide a control device for a variable displacement hydraulic motor capable of preventing the stall of a motor even at the occurrence of such trouble that a spool of a pressure compensation valve of the control device is stuck in a non-switching position due to a mechanical failure or a bite of dirt.
The control device for the variable displacement hydraulic motor is provided with a negative brake forcible switching control valve 23 switched to stop the supply of brake release pressure to a negative brake 21 and to self-hold the switching operation with the brake release pressure when motor driving pressure Pa, Pb supplied to the motor 1 through a motor driving circuit comprising passages 6, 7 exceeds the set pressure of a main relief valve and becomes pressure less than the set pressure of an overload relief valve 15a.
JP4315881 | Power steering device |
JPH03255203 | HYDRAULIC OPERATION VALVE |
JP6304273 | Work machine hydraulic drive |
JPH05126103A | 1993-05-21 | |||
JPH0682407U | 1994-11-25 | |||
JPH03115161U | 1991-11-27 | |||
JPH11301968A | 1999-11-02 | |||
JPH0681809A | 1994-03-22 |
Takenaka Yoshimichi