| 摘要 |
<p>The present specification discloses a disc brake comprising a clamp member (1) which is slidably connected to a torque taking member, with a hydraulic actuator mechanism (5) and an adjuster mechanism (27) being located within the clamp member (1) and a spring arranged to act on the clamp member (1) and adjuster mechanism (27) to provide a parking brake facility. The adjuster mechanism (27) comprises an adjuster nut (33) which is threadedly engaged on an axially movable actuator shaft (29) which acts on a friction pad (9), the adjuster nut (33) having an annular series of detent teeth (37, 45) formed on two axially and oppositely directed faces. The detent teeth (37, 45) are arranged such that when the teeth (37) on one face of the adjuster nut (33) are fully meshed with the teeth (39) on a part (41) of the adjuster mechanism (27) on which said spring acts, the teeth (47) on said detent collar (49) are engaged with but offset from the teeth (45) on the other face of the adjuster nut (33). The adjuster nut (33) engages an abutment (57) during normal hydraulic operation of the brake only after the adjuster nut (33) has moved a predetermined axial distance 'A', the adjuster nut (33) being caused to rotate on the actuator shaft (29) only when the adjuster nut has to travel a distance greater than said predetermined distance to apply the brake, the detent teeth (37, 45) on the said faces of the adjuster nut (33) then moving over the mated teeth on the detent collar (49) and said part (41) of the adjuster mechanism (27), the spring biassed detent collar (49) causing the adjuster nut (33) to rotate when the brake is released, to a position where the teeth (45) on said other face of the adjuster nut (33) are further meshed with the teeth (47) on the detent collar (49), subsequent parking brake operation causing the adjuster nut (33) to rotate to a position where the teeth (37) on said one face of the adjuster nut (33) are fully meshed with the teeth (39) on said one part (41) of the adjuster mechanism (27).</p> |
