| 摘要 |
In an automotive disc brake, the main hydraulic seal 18 is arranged in a trapezoidal annular groove 21 so that it distorts into a parallelogram shape during brake application and provides a resilient retraction force for the piston 17 in the cylinder 16 when the cylinder is depressurised. A combined dust seal and retraction control means 19 incorporates an abutment means 26, 28 which grips the piston and can move axially with the piston between retraction stop 31 forming the rear of a groove 34 and a setting stop provided by a flange on retainer 25. During brake application the piston slides through the abutment means 26, 28, which has its position on the piston set by the setting stop. On brake release, retraction brought about by main seal 18 is restricted to distance A by engagement of the abutment means with the retraction stop. |
