| 摘要 |
The technical field of the invention generally concerns electronically controlled hydraulic valves adapted for use in electro-hydraulically controlled automotive transmissions. The proportional pressure control valve 20 includes a hollow cage 42 pierced by cage tank ports 52, cage clutch ports 54, and by cage pump ports 56. The cage pump ports 56 receive fluid from a pump. The cage clutch ports 54 supply fluid to a hydraulic actuator, such as that for an automotive clutch. The cage clutch ports 54 supply the fluid at a pressure that is proportional to an electrical control signal applied to a solenoid coil 252 of the valve 20. The cage tank ports 52 return fluid from the valve 20 to a tank from which the fluid circulates back to the pump. Located in the cage 42 is a main spool 112 that is movable laterally relative to the cage 42 for controlling a flow of hydraulic fluid between the cage clutch ports 54 and either the cage pump ports 56 or the cage tank ports 52. An electromagnetically operated pilot valve regulates a control pressure of fluid applied to a control pressure surface 138 at one end of the main spool 112. A feedback pressure passage 126, having a feedback restriction orifice 128, couples the pressure of fluid in the cage clutch ports 54 to a feedback pressure surface 114 at the opposite end of the spool. The feedback restriction orifice 128 restrains the rate at which fluid may flow between the cage clutch ports 54 and the feedback pressure surface 114. One embodiment of the valve 20 includes a pressure spike suppression check valve 504 for relieving any abnormally high pressure that occurs in the cage clutch ports 54.
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