| 摘要 |
A hydraulic pressure control valve (15) for a fluid pressure operated clutch (18) includes a piston (21) responsive to a pilot control pressure at 24 as a proportion of source pressure and feedback pressure at 19 indicative of fluid pressure in the clutch to connect the clutch to source pressure whenever pilot pressure exceeds feedback pressure and to connect the clutch to drain (22) whenever feedback pressure exceeds pilot pressure. Pilot pressure is derived from source pressure by the use of a solenoid operated valve (25) responsive to an electrical square wave signal (26) to dump a proportion of the fluid in a passage (23) to a reservoir (11). The clutch may be for a charge speed transmission of a motor vehicle. <IMAGE> |
