VALVULA DE PRESSAO RESIDUAL

摘要

A check valve in an automotive braking system between the master cylinder and a wheel cylinder includes a screw or a piston mounted in the check-valve housing for overriding or opening the valve prior to a charging or filling operation to facilitate an evacuation of air from the system. A flow-regulating assembly in the valve includes an annular sealing disk biased by a restoring spring into a fluid-tight contact with an annular valve seat. Another restoring spring mounted in the housing in opposition to the first spring biases a spherical plug into a fluid-tight contact with an inner rim of the disk, this disk being mounted in a cup-shaped extension of a hollow shaft. In one embodiment the shaft extends from the flow-regulating assembly to the override screw; upon an inward shift the screw engages the free end of the shaft and thereby pivots the same and the sealing disk about a point on the valve seat. In another embodiment a tube traverses the shaft and the disk to engage the spherical plug and unseat the same from the inner rim of the disk in opposition to the force exerted by the second spring; the tube shifts longitudinally in response to an inward motion of the screw or piston, the same being provided with a fructoconical camming surface engaging the end of the tube opposite the spherical plug.