Creep-inhibiting device for an automotive vehicle equipped with an

Abstract

A creep-inhibiting device for use in an automotive vehicle equipped with a transmission mechanism coupled in series to a fluid coupling and having a frictionally engaging element. Control means interposed between the frictionally engaging element and an operating fluid source controls the power transmission capacity of the frictionally engaging element within a range from substantially zero to a predetermined value in dependence on a signal fluid pressure representative of engine load, to inhibit creeping of the vehicle when the vehicle engine is in a no-load state. The control means has a valve body selectively connecting and disconnecting an input fluid line to and from an output fluid line. A first pressure chamber defined by a first end face of the valve body is supplied with an operating fluid pressure in the output fluid line, while a second pressure chamber defined by a second end face of the valve body is supplied with the signal fluid pressure. A third fluid line having a restriction always connects the input and output fluid lines with each other, and a resilient member urges the valve body in a direction of connecting the input fluid line to the output fluid line. The operating fluid pressure in the output fluid line is allowed to escape through a drain line to a lower pressure zone by an amount corresponding to an amount by which the valve body is biased in a direction of disconnecting the input fluid line from the output fluid line.