| 摘要 |
<p>PURPOSE:To enable miniaturization to be attained of a reservoir tank for working fluid by providing an automatic clearance adjusting part adjusting a braking clearance between both friction pads and a brake disk and a stopper restricting a retracting position of the first friction pad. CONSTITUTION:When a brake is released, as a brake disk 6 rotates the first friction pad 91 is retracted, and its retracted position is restricted by bringing a back plate to be opposed to a stopper S1, so that a piston 13 places its retracting position in almost a fixed position, generating the volume of a pressure oil chamber 15 almost in a fixed value. While, when the first and second friction pads 91, 92 are worn exceeding a specified amount by controlling a parking brake, an adjusting bolt 24 is rotated in accordance with a wearing amount by actuating an automatic clearance adjusting part A advancing the second pad 92 toward the brake disk 6 ensuring a proper braking clearance. Since this adjustment is controlled in a side of a mechanically-operated mechanism M2, a hydraulically-operated mechanism M1 is given no influence, and the piston 13 is prevented from changing its retracting position.</p> |
