HYDRAULICALLY OPERATED TRANSMISSION CONTROL ARRANGEMENT

摘要

A hydraulically operated control arrangement for a transmission includes a spring-loaded pressure regulating valve which slides into a position to cut off an exit chamber for hydraulic fluid from an input chamber for pressurized hydraulic fluid so as to route the incoming hydraulic fluid exclusively to the transmission for various control and lubricating functions when hydraulic fluid pressure in the input chamber falls below a first threshold value. Hydraulic fluid applied to the input chamber continues to feed a first plurality of functions within the transmission via the input chamber and a second plurality of functions in the transmission via an intermediate chamber disposed between the input and exit chambers and in communication with the pressure regulating valve until such time as the hydraulic fluid pressure at the input chamber drops below a second threshold value so as to permit the pressure regulating valve to cut off the intermediate chamber from the input chamber. Loss of hydraulic fluid pressure also causes movement of a power takeoff control lever to the disengaged or off position through the action of a power takeoff control valve which operates a detent arrangement and movement of a planetary control lever into a low position through the action of a high-low control valve.