Patent ID: 7070025
Filing Date: 2006-07-04
Classification: F16D

Abstract:
1. A drum brake apparatus, comprising: a drum; first and second brake shoes provided in the drum; a wheel cylinder that presses the first and the second brake shoes; and an automatic clearance adjusting device that automatically adjusts positions of the first and second brake shoes in accordance with wear amounts of the first and second brake shoes, the automatic clearance adjusting device including; wherein the outer surface of the adjuster gear is formed in such a manner that a shortest distance defined between a rotation center of the adjuster gear and the cam surface where the ratchet pawl abuts is increased as the adjuster gear rotates in a biased direction, and the wheel cylinder rotates the adjuster restricting lever against a biasing force of the lever restricting spring so as to engage the ratchet teeth with the ratchet pawl when the controlling force of the wheel cylinder becomes larger than a predetermined force.