Hydrostatic continuously variable transmission

摘要

A ball and piston valve for controlling the flow of hydraulic fluid to a motive means have the ball and piston spring biased in opposing directions and with both initially subject to a first hydraulic fluid pressure that allows the springs to cause the ball to be unseated from its seat whereby fluid is directed to a fluid tank and wherein the ball is of sufficiently larger diameter than the piston that upon an increase in fluid pressure the ball is seated and remains seated when the pressure drops to the first hydraulic fluid pressure whereby the motive means to which the fluid is directed when the ball is seated does not have a sudden lurch upon a subsequent increase in pressure.