| 摘要 |
A drum brake assembly provides a pair of brake shoes which are movable by a hydraulic actuator to a braking position. The hydraulic actuator is carried by a backing plate and the pair of brake shoes is movable relative to the backing plate. A piston is slidably mounted within a bore on the hydraulic actuator and pressurized fluid communicated to the bore acts against the piston to move the piston and pair of brake shoes. A partition is also disposed within the bore to substantially define a secondary chamber which receives pressurized fluid from the bore. The partition is movably disposed within the bore and resiliently engaged with the piston so that increased pressure within the bore is transmitted to the piston via the partition and the resilient engagement. Moreover, the partition controls venting of the secondary chamber so that upon contact of the pair of brake shoes with a drum, backlash or retraction of the pair of brake shoes is limited.
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