| 摘要 |
A drum brake assembly includes a pair of brake shoes which are carried by a backing plate and engageable with a hydraulic actuator. The hydraulic actuator is operable to move the pair of brake shoes from a rest position to a braking position. A strut extending between the pair of brake shoes cooperates with a parking arm to move the pair of brake shoes to the braking position during a parking brake application. A support assembly on the backing plate is disposed opposite the hydraulic actuator for the purpose of absorbing braking torque developed by the pair of brake shoes. The support assembly comprises a pair of slots and a lever. The lever is movable in response to movement of the parking arm to adjust the position of the pair of blocks relative to each other. In a first position the blocks are in abutment with the backing plate while in a second position the blocks are free to move a limited amount relative to the backing plate. Moreover, the lever imparts a separating force to the pair of brake shoes via the blocks during a parking brake application to expand the brake shoes radially. This expansion is in addition to the movement imparted to the brake shoes by the strut and parking arm. |
