Pin slide-type floating disc brake

A pin slide-type floating disc brake comprising:

• a mount assembled to a vehicle body;
• a caliper assembled to be movable with respect to the mount in a rotor shaft direction, wherein either one of the mount and the caliper is formed with a slide hole extending in the rotor shaft direction;
• a support pin provided in the other one of the mount and the caliper to extend in the rotor shaft direction and slidably inserted into the slide hole;
• and
• a tubular pin boot covering a part of the support pin protruding from the slide hole,
• wherein the pin boot integrally includes;
• a pin-side annular seal portion fitted to an outer periphery of the support pin;
• a slide hole-side annular seal portion fitted to an annular accommodation groove provided at an opening end portion of the slide hole, and including an outer peripheral part coming in pressure contact with a bottom wall surface of the annular accommodation groove and an inner peripheral part joined to an outer peripheral surface of the support pin;
• and
• an extendable tubular bellows portion connecting the pin-side annular seal portion and the slide hole-side annular seal portion,
• wherein the outer peripheral part of the slide hole-side annular seal portion of the pin boot includes:
• an annular outer peripheral seal surface which comes in pressure contact with the bottom wall surface of the annular accommodation groove;
• and
• an elastic restriction portion which is elastically engaged with both side wall surfaces of the annular accommodation groove to elastically restrict movement of the slide hole-side annular seal portion in the rotor shaft direction, in the annular accommodation groove, and
• wherein the inner peripheral part of the slide hole-side annular seal portion of the pin boot includes:
• an inner peripheral annular groove which opens to the outer peripheral surface of the support pin at a middle portion thereof in the rotor shaft direction;
• a first annular lip portion which comes in sliding contact with the outer peripheral surface of the support pin to be movable in the rotor shaft direction on a bellows portion side of the inner peripheral annular groove;
• and
• a second annular lip portion which has a retraction function by being engaged with the outer peripheral surface of the support pin so as to be elastically deformable in the rotor shaft direction on an opposite side to the bellows portion of the inner peripheral annular groove.