| 摘要 |
An electrically controlled clutch control valve which provides both hydraulic flow and hydraulic pressure control to the clutch cylinder comprises a valve body 11 containing a spool 12 maintained in contact with the drive pin 13 of the electrical actuator 14 by a spring 20. Port 16 is in communication with the clutch cylinder and when an increase in pressure is required, spool 12 is pushed by actuator 14 to allow additional fluid to flow from the pump port 17. When pressure is higher than required, the spool is moved to allow port 16 to communicate with the tank port 18. To control flow, positional feedback with respect to the spool is provided by a displacement detector 19 and the spool is moved to known positions (FIGS 3 and 4). When a position of maximum pressure is reached a further displacement detector on the clutch cylinder instructs the control circuit not to increase the pressure further. Gear changing is permitted when the ports 17, 18 are isolated from port 16 and the clutch is disengaged. <IMAGE> |
