| 摘要 |
<p>PURPOSE:To permit free control of the oil hydraulic circuit pressure at the time of acceleration and deceleration and also permit idling with the lever neutral and also torque control at the time of applying brake by reverse lever operation. CONSTITUTION:A releaf valve 5 and a directional control valve 2 are provided between a discharge pipe 11 of an oil hydraulic pump 1 and a return pipe 12, and the directional control valve 2 is connected to an oil hydraulic motor 4 via pipes 41 and 42. The pressure from an oil hydraulic' pressure source 30 is controlled by an operational valve 3 which consists of a pair of variable reducing valves 6 and 7. The resultant pressure is introduced as secondary side pressure into the directional control valve 2 and a releaf valve 5. The change of the secondary side pressure thus controls the set pressure of the releaf valve 5. The pressure in the pipes 11 and 41 thus constitutes the circuit pressure corresponding to the operation angle of the lever 31, and torque control of the oil hydraulic motor 4 can be made like a mechanical system.</p> |
