Patent ID: 8118567

Claim:
A swash plate type piston pump motor in which: a plurality of pistons are arranged in a circumferential direction in a cylinder block configured to rotate with a rotating shaft; the pistons reciprocate such that tip end portions thereof are guided along a smooth surface of a swash plate; and the swash plate is slidably supported by a swash plate support so as to be able to tilt with respect to the rotating shaft, wherein: a circular-arc smooth convex surface opposed to the swash plate support is formed on a surface of the swash plate, the surface being opposite to the smooth surface of the swash plate, and an oil film keeping groove portion extending in a slide direction is concavely formed on the convex surface; the swash plate support closes one side-opening of a substantially tubular casing main body and constitutes a part of a casing, and a bearing for rotatably supporting the rotating shaft is internally fitted in the swash plate support and a holding member is attached on an outer side of the bearing; a slide surface of the swash plate support is a circular-arc concave surface, the slide surface supporting the convex surface of the swash plate, and a pressure oil supply port which opens and faces the groove portion is formed on the concave surface; the concave surface of the swash plate support includes a first quenched portion partially quenched by laser light; and the concave surface including the first quenched portion further includes a second quenched portion which is formed along an outer periphery of the concave surface so as to entirely surround the first quenched portion and a non-quenched portion in a closed loop shape.