| 摘要 |
An actuator (24) including first and second members (25 and 31), each of which has a rolling surface (32, 33). The first and second members (25, 31) being arranged so that the respective rolling surfaces (32, 33) are disposed in substantially opposed relationship and for relative rotation. The actuator (24) further including rolling elements (37) disposed between the first and second members (25, 31) and in engagement with the respective rolling surfaces (32, 33) thereof, that engagement causing the rolling elements (37) to roll relative to the rolling surfaces (32, 33) upon relative rotation between the first and second members (25, 31). At least one of the rolling surfaces (32, 33) being at least part conical so as to define a generally curved and tapered surface. Each rolling element (37) being constrained to roll in a spiral path upon relative rotation of the first and second members (25, 31) so as to traverse the gradient of the taperred rolling surface (32, 33) and the other of the rolling surfaces (32, 33) having a profile so that traversal of the tapered rolling surface by the rolling elements (37) causes a shift in the spacing between the first and second members (25, 31). The actuator (24) is suitable for use in a disc brake caliper or a drum brake for actuating the brake friction lining into engagement with the disk rotor or drum brake surface. |
