Patent attributes
A valve assembly (10) comprising a valve member (14) having surfaces (70, 72, 74, 76, 78) radially sized and axially situated to provide an axial sealing force to insure leakfree operation. When the valve member (14) is in a supply position, the sum of fluid forces imposed on the radial surfaces is positive towards supply position, and, when the valve member (14) is a nonsupply position, the sum of fluid forces imposed on the radial surfaces is positive towards the nonsupply position. The valve assembly (10) is compatible with a piezo-type actuator (18) that provides lift-shift forces early in its stroke. Once movement of the valve member (14) has been initiated by the actuator (18), the fluid forces can be relied upon to complete the shift and seal the valve member (14) against the corresponding seat (40/42).
