| 摘要 |
<p>A hand-brake valve for a vehicle hydraulic brake system of the kind in which hydraulic pressure keeps a spring-actuated brake (3) in a released position, includes a pressure- balanced control spool (16) against which bears a hand-brake lever (2) and a reaction piston (26) having two opposed effective areas (27, 28). The reaction piston is permanently exposed to the pressure from the fluid source (4) which urges the spool towards the brake release position, and in the opposite direction, it is exposed to the brake pressure in the chamber (20). This permits sensitive actuation of the brake. <IMAGE></p> |
