| CPC F01B 13/061 (2013.01) [F01B 1/0644 (2013.01); F01B 1/0648 (2013.01)] | 4 Claims |
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1. A bearing device for a radial piston machine, comprising:
a cam ring having a cam face on a radially inner side thereof;
a rotor rotatably supported in the cam ring and having a plurality of cylinders formed radially with respect to a rotational axis of the rotor;
a cylindrical piston arranged slidably in the cylinder;
a cylindrical roller arranged at an axial end of the piston on a cam ring side, a rotational axis of the roller being arranged parallel to the rotational axis of the rotor so that the roller rolls on the cam face; and
a half bearing arranged between the piston and the roller, the half bearing being composed of a slide layer forming an inner circumferential surface for supporting the roller and a steel back metal layer forming an outer circumferential surface held by the piston, wherein:
the piston comprises, at the axial end on the cam ring side, a recessed holding surface of partial cylindrical shape for holding the half bearing, and holding side surfaces formed on both axial sides of the recessed holding surface;
each holding side surface comprises:
a ridge portion extending in a radial direction of the recessed holding surface and an axial direction of the piston, and having an arc-shaped or elliptic-arc-shaped profile in a cross section perpendicular to the axial direction of the piston so as to protrude toward a radially inner side of the piston; and
side surface portions expanding on both sides of the ridge portion in a circumferential direction of the piston;
the half bearing comprises: a partially cylindrical portion of partially cylindrical shape, the partially cylindrical portion including axial end faces at both axial ends thereof, each axial end face extending in a plane perpendicular to the axial direction; and protruding portions protruding toward axially outer sides from the axial end faces at a circumferential center of the partially cylindrical portion;
each of the protruding portions comprises: two circumferential side surfaces extending from the axial end faces; and a protruding portion end face extending between the two circumferential side surfaces to face toward the axially outer side;
the protruding portion end face comprises:
a central recessed surface located in a circumferential center of the half bearing and recessed toward an axially inner side of the half bearing; and
two support recessed surfaces located on both circumferential sides of the central recessed surface and formed into an arc shape or an elliptic arc shape so as to correspond to the profile of the ridge portion, so that only the two support recessed surfaces of the protruding portion end face are in contact with the ridge portion of the piston while the central recessed surface, the circumferential side surface and the axial end faces are not in contact with any of the ridge portion and the side surface portion; and
the protruding portion has a circumferential length corresponding to an angle of circumference of 40 to 70° of the half bearing.
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