Patent ID: 7836817

Claim:
A fluid pressure cylinder comprising: a tubular cylinder body having a cylinder chamber, which is elliptically shaped in cross section; a piston formed with an elliptical shape in cross section corresponding to said cylinder chamber, said piston being disposed displaceably along an axial direction inside of said cylinder chamber; and a pair of cover members accommodated inside of said cylinder chamber and closing said cylinder chamber, and having arcuate shaped first projections on an outer circumferential surface thereof that project toward an inner wall surface of said cylinder chamber, said first projections being arranged as a pair, in symmetrical positions centrally about an axis of said cover members, and bulging outwardly on an outer circumferential surface of said cover members, wherein a pair of recesses are formed on said cylinder chamber, which are recessed with respect to the cross sectional elliptically shaped inner wall surface thereof, said first projections being inserted into said recesses and retained therein against movement in the axial direction of said cylinder chamber, and wherein said recesses are recessed in arcuate shapes corresponding to said first projections, in directions away from the center of said cylinder chamber, and a radius of curvature of said recesses is set to be smaller than a radius of curvature on respective end portions of said cylinder chamber.