Closed loop control for shift fork position.

摘要

A hydraulic closed loop control (10) for positioning a transmission shift rail (12) and synchronizer fork (14) has recesses (70,72,74) on the shift rail and ports (76-86) in a valve body (18) in which the shift rail is disposed. Fluid flow between the ports as permitted by the shift rail recesses controls the position of valves (36,52) which in turn control the position of the shift rail. The valves control the position of the shift rail by routing pressurized fluid to one of two opposing sides of a piston (16) fixed to the shift rail in response to the flow of fluid from the valve body ports. The pressurized fluid moves the shift rail to a desired position (20,22) with the flow of pressurized fluid being interrupted when that position is reached.