Trim valve for a fluid operated friction torque transmitting device

摘要

A trim valve controls the pressure rise and pressure gain in a torque transmitter. The trim valve controls the distribution of a system pressure to the torque transmitter in a controlled manner such that the apply pressure of the torque transmitter has a desired gain rate. A spool valve controls the admission of system pressure through a sleeve valve for distribution to the torque transmitter in response to a control pressure. The trim valve has bias spring elements that control a sleeve member of the trim valve in response to the apply pressure at the torque transmitter. The rate at which the apply pressure rises in relation to the control pressure is established by the bias spring elements which can be a single variable rate member or a plurality of parallel members. If parallel members are used, they are positioned to be sequentially engaged by the sleeve valve during linear movement in response to a change in the apply pressure.