Patent ID: 7547201

Claim:
A compact simplified compressor apparatus comprising: a rotating shaft rotationally driven by a motor; a compact compressor provided with a rod attached to the rotating shaft via a crank, a piston having a peripheral groove in an outer peripheral surface thereof and arranged in an end of said rod, a cylinder having a cylinder chamber receiving the piston so as to freely reciprocate, and a ring seal sealing between said piston and an inner peripheral surface of the cylinder chamber; an air feeding means for feeding a high-pressure air from the compact compressor to a tire; and a power source plug supplying an electricity to said motor, said rod and the piston are formed by an integrally formed body made of fiber reinforced plastics (FRP), said peripheral groove of said piston has a groove wall surface in a rod side and a groove wall surface in an opposite rod side, each extending from each side of a groove bottom surface, said ring seal is provided with a base portion having a base surface seating on said rod side groove wall surface, and inner and outer lip portions, which extend from said base portion radially inwardly and outwardly, respectively, so as to be opened toward the opposite rod side, in a free state in which said ring seal is not attached to said peripheral groove, an inner peripheral surface of said inner lip portion comprises an inclined surface which is inclined at an angle β 1 between 10 and 40° with respect to a line perpendicular to said base surface, and a curved surface with a shape of a convex circular arc, which is connected to a leading end side thereof, and an outer peripheral surface of said outer lip portion is constituted by an inclined surface which is inclined at an angle β 2 between 10 and 40° with respect to the line perpendicular to said base surface, and an inclined surface in a leading end side which intersects the inclined surface at an angle γ in a range of 80 to 140°, said groove wall surface in said non-rod side of said peripheral groove and said groove wall surface in said rod side are inclined so as to increase a groove width toward an outer side in a radial direction, and angles α 1 and α 2 of the inclination with respect to a radial line perpendicular to said groove bottom surface are respectively set in a range of 5° to 20°, said groove bottom surface is in parallel to a central axis of the piston, and said base surface of the ring seal is at a right angle with respect to the central axis of the ring seal in said free state.