Importance

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Abstract

This invention generally concerns electronically controlled hydraulic valves for use in electro-hydraulically controlled transmissions. The proportional pressure control valve 20 includes a hollow cage 42 pierced by cage tank ports 52, cage clutch ports 54, and 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. The cage tank ports 52 return fluid from the valve 20 to a tank from where fluid circulates back to the pump. Main spool 112 controls fluid flow between cage clutch ports 54 and cage pump ports 56 or cage tank ports 52. An electro-magnetically operated pilot valve regulates fluid pressure applied to a control pressure surface 138. A feedback pressure passage 126, having feedback restriction orifice 128, restrains the rate fluid flows between the cage clutch ports 54 and the feedback pressure surface 114.

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First Claim