To facilitate the machining and improve the precision of a gap automatic regulating means by providing the gap automatic regulating means for automatically regulating the gap between a brake drum and a brake shoe, an operating element for parking brake for pressing a piston, and the like.
A gap automatic regulating means 36 in a first brake means 2 is provided with a one-way clutch 37 arranged between the inside surface of a piston 8 and the outside surface of a sleeve 30, a cylindrical-inclined surface 38, a rotating ring 25 and the like. When a parking brake 6 is operated, its operating element 7 is moved to press the tappet 19 of the brake means 2 axially outward. A brake shoe is pressed through an adjuster shaft 11 to brake a vehicle. When the gap between a brake drum and the brake shoe exceeds a prescribed value due to the wear of the brake shoe, it is automatically regulated by the gap automatic regulating means 36 consisting of the adjuster shaft 11, the rotating ring 25 and the like.
NAITO TETSUYUKI
OCHI MITSURU
