US Patent 9285006 Shock absorber

A shock absorber including a piston inserted into a cylinder (2) having a hydraulic oil sealed therein. An outer tube (3) is provided around the outer periphery of the cylinder to form a reservoir (4) therebetween. A bottomed circular cylindrical casing (25) is joined to a side surface portion of the outer tube, and a damping force control valve (27) is housed in the casing. The bottomed circular cylindrical casing has a bottom (25A) formed with a joint surface (25B) curved along the outer peripheral surface of the outer tube and a flat inner surface (25C). The casing is integrally formed by forging.