Flow restrictor assembly in transmission clutch control system

摘要

There is provided in accord with the present invention a work vehicle having a transmission and a clutch control system controlling the vehicle clutches, with the clutch control system including a flow restrictor assembly. The flow restrictor assembly comprises a modulator valve and an unloading valve in fluid communication with the fluid supply and the clutch control system. The unloading valve is selectively in fluid communication with the modulator valve through a modulator tank orifice and is responsive to fluid pressure changes acting on the modulator valve, as the clutch control system operates to control the length of time the modulator valve regulates the rate of flow of fluid to the clutch control system through the modulator tank orifice. In one embodiment the unloading valve spool is nested inside the modulator valve spool.