PURPOSE: To prevent the separation of a main shaft by attaching the main shaft to the thrust bearing surface of a rotary swash plate with its inclination at a specific minute angle toward the top dead center of a piston to uniformly press the main shaft against the top dead center side of a radial needle bearing.
CONSTITUTION: A rotor 14 is formed of a wedge shaped rotary swash plate attached to the end of a main shaft 16, and reciprocates a piston through an oscillating plate pressed relatively rotatably onto the inclining surface of the rotor 14. In this case, the main shaft 16 is tiltingly attached to the rotor 14. Namely, when the thrust bearing surface of the rotor 14 is denoted by ST, and an axis perpendicular to the thrust bearing surface ST by OR, the center line OS of the main shaft 16 is inclined at an angle of θ1 from the above- mentioned axis OR toward the top dead center of the rotor (that is, the thicker side of the rotor). When the axial length of a radial bearing is denoted by l, and a clearance between the bearing and the main shaft 16 by c, the angle of θ1 is selected so as to satisfy the formula of θ1≥tan-1(C/l), namely the angle of θ1 is set to about 0.5°.
SHIMIZU SHIGEMI
HATAKEYAMA HIDEHARU
KUMAGAI SHUZO
