| 摘要 |
<p>Single acting hydraulic cylinder actuators (35, 45) for adjusting the swash plate tilt in a pump (15) are connected to a charge pump (P) and to respective bypass valves (33, 37) which are solenoid valves, open when de-energised. As illustrated the system is in neutral with both valves open and the swash plate at zero angle. To set a desired pump displacement, a control circuit (52) closes one solenoid valve and the corresponding actuator (35 or 45) tilts the swash plate. When the desired tilt has been reached, as indicated by a feedback transducer (59), the circuit 52 energises also the other valve and both hydraulic actuators are pressurised to lock the swash plate in position. The system requires a minimum of electrohydraulic parts, namely the two simple solenoid valves (33, 37). In an alternative embodiment the swash plate of the motor can be adjusted in a similar manner to permit a further increase in output speed to be obtained after the pump swash plate has been displaced to its maximum extent. <IMAGE></p> |
