| 摘要 |
<p>A brake drum (20A) comprises a wheel hub (21), a brake panel (30) and a drum brake mechanism (40). A clearance (52) between the wheel hub and the brake panel is sealed by a labyrinth mechanism (50). In the portion of the drum brake located above an axle (12), the labyrinth mechanism is fitted at the outer peripheral surface (51) of the brake panel in a recess (23). The brake panel has in its outer peripheral surface an outer labyrinth groove (53) and an inner labyrinth groove (54) in the order mentioned as seen from the front of the panel width toward the recess. The cross-sectional area (A1) of the outer labyrinth groove is smaller than the cross-sectional area (A2) of the inner labyrinth groove.</p> |
