| 摘要 |
<p>PROBLEM TO BE SOLVED: To suppress dragging of a pad by providing a retract setting means increasing piston retract amount on a back thickness absence side more than that on a back thickness presence side between a cylinder part and a piston. SOLUTION: Cylinder opening side chamfering amount A1 on a back thickness absence side in an annular groove 13a1 of a cylinder part 13a of a caliper 13 is increased more than cylinder opening side chamfering A2 on a back thickness presence side and deformation amount of a retraction ring 15 at the time of a braking is made larger on a back thickness absence side. Thus, piston retract amount on the back thickness absence side becomes larger than that on the back thickness presence side. Large quantity of back thickness absence side portion of a piston 14 is returned at the time of depressurization after the braking. Therefore, the caliper 13 is warped by reaction of braking hydraulic pressure at the time of a braking, the back thickness absence side portion of the piston 14 can be sufficiently returned by the ring 15 at the time of depressurization after the braking, even if moving amount of the back thickness absence side portion of the piston 14 becomes large, a sufficient clearance can be secured between the piston 14 and the pad 16 and dragging of the pad 16 can be suppressed.</p> |
