CYLINDER BLOCK AND MACHINING METHOD THEREOF

摘要

Provided are a cylinder block and a machining method thereof, wherein low friction can be achieved, existing facilities can of course be used to easily obtain the machined shape of a bore, and it is possible to form a large tapered shape and to effectively suppress seizing. A machined shape of a bore (111) can be formed by honing including a first step and a second step. In the first step, the cross section of the bore is given a substantially circular shape by varying the rotating speed of a head (302) or the surface pressure from a grind stone (303), and the inner surface of the bore is machined so that the diameter of the substantially circular shape varies along the center axis. In the second step, the rotating speed of the head (302) and the surface pressure from the grind stone (303) are kept constant, whereby the hatch shape of at least part (e.g. all) of the inner surface of the bore (111) is corrected to a predetermined shape.