Disc brake device

Claim 1

An improved disk brake device including a piston, an automatic adjuster and a sleeve piston within the cylinder of a caliper body, wherein braking and automatic braking-gap adjustment are achieved by a hydraulic input, and said piston being pushed by a mechanical input through said sleeve piston and said automatic adjuster for braking, the improvements comprising; the cylinder of said caliper body having a larger-diameter portion and a smaller-diameter portion connected thereto, said larger and smaller-diameter portions fluid-tightly and movably receiving said piston and said sleeve piston, respectively, to define a hydraulic chamber within said cylinder; said automatic adjuster disposed within said hydraulic chamber including an adjusting nut and an adjusting bolt which are engaged with each other in a multi-threaded relation, said adjusting nut being biased in the braking direction by means of a first spring abutting said piston, whereby said nut is restrained from rotating; said sleeve piston including a smaller-diameter portion and a larger-diameter portion connected thereto, said larger-diameter portion being disposed to said larger-diameter of said cylinder so that said sleeve piston is restrained from rotating by said cylinder but is movable fluid-tightly and axially of said cylinder so as to maintain said hydraulic chamber, and said larger-diameter portion being at its end with a clutch face to be in engagement, within said hydraulic chamber, with a clutch portion of said adjusting bolt biased by a second spring in the counter-braking direction and a portion with which said adjusting bolt is rotatably engaged, said engagement portion and a portion of said adjusting bolt to be in engagement therewith being provided with an atmospheric chamber therebetween, and said smaller-diameter portion cooperating with said mechanical input.