摘要 |
2103354 9220937 PCTABS00017 The disc brake (10, 106, 108, 206) with powered integral parking mechanism comprises a twin piston disc brake (106, 108, 206) having a screw member (22, 24; 122, 124; 222, 224) and nut (28, 29; 228, 229) adjuster mechanism. The twin pistons (16, 18; 216, 218) receive service braking hydraulic pressure to effect a service braking application, and also may be displaced mechanically for a parking application by way of the rack (80, 280) and pinion (47, 48; 247, 248) parking mechanism that is operated by hydraulic pressure. The rack (80, 280) and pinion (47, 48; 247, 248) parking mechanism may be located within the caliper housing (20, 220) such that the rack (80) extends between respective drive pinions (47, 48) located about the screw members (22, 24) in order to effect rotation of the screw members (22, 24) in opposite directions, or the rack (280) may extend longitudinally across the same side of both drive pinions (247, 248) to effect rotation of the drive pinions (247, 248) and associated screw members (222, 224) in the same direction of rotation. The drive pinions (47, 48; 247, 248) have ratchet teeth (49) which engage corresponding ratchet teeth (39) on screw member flanges (32, 34) such that during release the height (B) of a flange ratchet tooth (39) determines the running clearance of the disc brake pads.
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