Abstract: A method for producing a hollow piston for compressor by coupling a piston top side member and a rotation preventing portion side member where a rotation preventing portion and a cylindrical portion are formed integrally. When the rotation preventing portion side member is formed, an intermediate material for forging the rotation preventing portion side member is formed, the cylindrical portion of the rotation preventing portion side member is forged in a uniaxial direction by molding for pushing the cylindrical portion rearward in a punch inserting direction using a punch having a tip portion formed asymmetrically to a piston axis, and a material theft portion is formed to copy the asymmetric profile at the tip of the punch on the rotation preventing portion side bottom of the hollow section for forming the cylindrical portion. A hollow piston can be produced by simple and inexpensive forging and the position of the center of gravity can be brought closer to the axis of the cylindrical portion of the piston.

Abstract: A method for forming a spherical concave surface includes the steps of bringing a tool into contact with a material to be formed, rotating the material around a predetermined axis, and moving the tool in a first direction parallel to a central axis of the tool and in a second direction perpendicular to the first direction for forming the spherical concave surface on the material. The method also may include the steps of forming an acute first angle between the central axis and the predetermined axis, and forming an acute second angle between the central axis and a tangent line parallel to the central axis and passing through a first end point of the spherical concave surface.

Abstract: In a method of machining the spherical surfaces of a piston for a swash plate type compressor for machining the spherical surfaces of the swash-plate-passing-slot of the piston through which a swash plate passes, wherein the swash plate rotates about a rotating axis and the peripheral edge surfaces of the swash plate carry out a reciprocating motion in a direction substantially along the rotating axis and the motion of the swash plate is converted into a reciprocating motion in a cylinder bore by the piston through spherical shoes. The method comprises the step of machining the spherical recesses of both the end surfaces of the swash-plate-passing-slot for accommodating and retaining the spherical portions of the spherical shoes by moving the center axis of a tool element having a spherical cutter from the rotational center axis of a machine tool while rotating the tool element.

Abstract: In a swash plate type compressor having a shoe interposed between a swash plate and a concave surface of a piston, the concave surface has a first and a second spherical surface which are adjacent to and offset from each other to make a slight step extending along the concave surface. The shoe has a spherically convex surface received in the concave surface. In a condition where the spherically convex surface is received in the concave surface, the slight step serves to cause a small gap between the spherically convex surface and a part of the first spherical surface. When the swash plate is rotated together with a rotary shaft, the shoe converts a rotation of the swash plate into a reciprocating motion of the piston.

Abstract: In a swash plate type compressor in which a shoe (3) is interposed between a swash plate (5) and a reciprocally movable piston (2), a concave curved surface (21a) is made at an end of the piston to have an elliptical portion with an elliptical shape in cross section. The shoe has a convex spherical surface inserted into the concave curved surface and reciprocally moves the piston in accordance with a rotation of the swash plate.

Abstract: In a swash plate compressor (1) comprising a shoe (8) disposed between, and being in sliding contact with, a piston (7) and a swash plate (6), at least one of a shoe receiving surface (73e) of the piston (7) and a piston-side sliding surface (8b) of the shoe (8) is provided with an oil path (73f, 73g) for allowing the flow of a lubricating oil therebetween.