| 摘要 |
<p>A drum brake (10) having first (14) and second (16) brake shoes retained on a backing plate (20) and moved into engagement with a drum (18) to effect a brake application corresponding to a desired braking input supplied to a actuator member (28). The actuator member (28) has a housing (50) with a first bore (54) therein connected to a cross-bore (56). A pinion (58) located in the first bore (54) has a shaft with first end (60) and a second end (62). The shaft has teeth (68) thereon adjacent the first end (60) and a gear (64) connected to the second end (62). First (74) and second (76) racks which are located in the cross-bore (56) have teeth (67, 67') thereon which mesh with the teeth (68) on the pinion (58). A first linkage member (28) connects the first rack (74) with the first brake shoe (14) while a second linkage member (28')connects the second rack (76) with the second brake shoe (16). The pinion (58) receives a rotary torque corresponding to a desired braking input which is translated into linear movement of the first (74) and second (76) racks through the meshing of the first teeth (68) with the second teeth (67, 67'). The linear movement of the first (74) and second (76) racks supply a force which moves the first (14) and second (16) brake shoes into engagement with the drum (18) to effect a desired brake application. A lever (90) connected to the pinion (58) adjusts the first (28) and second (28') linkage members to maintain a desired running clearance between the first (14) and second (16) brake shoes and drum (18).</p> |
