Bearing device for radial piston machine

Patent metadata

Field	Value
Publication number	US-12018566-B2
Application number	US-202117483869-A
Country	US
Kind code	B2
Filing date	Sep 24, 2021
Priority date	Sep 28, 2020
Publication date	Jun 25, 2024
Grant date	Jun 25, 2024

Abstract

A bearing device includes a piston arranged in a cylinder of a rotor, and a half bearing mounted on the piston to support a roller. The piston includes a recessed holding surface, and holding side surfaces on both axial sides thereof. Each holding side surface includes a ridge portion having an arc-shaped or elliptic-arc-shaped profile protruding toward a radially inner side of the piston. The half bearing includes a partially cylindrical portion, and protruding portions protruding from axial end faces thereof. Each protruding portion has a protruding portion end face which includes a central recessed surface, and two support recessed surfaces located on both circumferential sides thereof, that have an arc shape or an elliptic arc shape to correspond to the profile of the ridge portion, so that only the two support recessed surfaces are in contact with the ridge portion.

First claim

The invention claimed is:

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 circumferentially extending between both circumferential end faces of the half bearing, the partially cylindrical portion having the same axial length as those of the circumferential end faces over the entire circumferential direction of the half bearing, and thereby defining axial end faces on both axial sides thereof that extend in a plane perpendicular to the axial direction of the half bearing; and
a protruding portion extending toward an axially outer side from each of the axial end faces of the partially cylindrical portion, and formed over the entire circumferential direction of the half bearing integrally with the partially cylindrical portion;

each of the protruding portions comprises a protruding portion end face facing toward the axially outer side;
the protruding portion end face comprises:
a central recessed surface located at a circumferential center of the half bearing and recessed toward an axially inner side of the half bearing;
two support recessed surfaces located on both circumferential sides of the central recessed surface and each formed into an arc shape or an elliptic arc shape so as to correspond to the profile of the ridge portion; and
two tilted surfaces located on both circumferentially outer sides of the two support recessed surfaces and extending up to the circumferential end faces, the two tilted surfaces being formed so that an axial protrusion amount of each of the tilted surfaces from the axial end face becomes smaller from a support recessed surface side toward a circumferential end face side, 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 and the tilted surfaces are not in contact with any of the ridge portion and the side surface portion; and

the two support recessed surfaces and the central recessed surface have, as a whole, a circumferential length corresponding to an angle of circumference of 40 to 70° of the half bearing.

2. The bearing device according to claim 1 , wherein the central recessed surface has a circumferential length which is 25 to 75% of the circumferential length of the two support recessed surfaces and the central recessed surface as a whole.

3. The bearing device according to claim 1 , wherein the protruding portion end face further comprises a parallel surface between the tilted surface and the support recessed surface, the parallel surface having a constant axial protrusion amount from the axial end face.

4. The bearing device according to claim 1 , wherein a bearing wall thickness in the protruding portion of the half bearing is smaller than a bearing wall thickness in the partially cylindrical portion.

5. 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 circumferentially extending between both circumferential end faces of the half bearing, the partially cylindrical portion having the same axial length as those of the circumferential end faces over the entire circumferential direction of the half bearing, and thereby defining axial end faces on both axial sides thereof that extend in a plane perpendicular to the axial direction of the half bearing; and
a protruding portion extending toward an axially outer side from each of the axial end faces of the partially cylindrical portion, and formed over the entire circumferential direction of the half bearing integrally with the partially cylindrical portion;

each of the protruding portions comprises a protruding portion end face facing toward the axially outer side;
the protruding portion end face comprises:
a central recessed surface located at a circumferential center of the half bearing and recessed toward an axially inner side of the half bearing;
two support recessed surfaces located on both circumferential sides of the central recessed surface and each formed into an arc shape or an elliptic arc shape so as to correspond to the profile of the ridge portion; and
two tilted surfaces located on both circumferentially outer sides of the two support recessed surfaces and extending up to the circumferential end faces, the two tilted surfaces being formed so that an axial protrusion amount of each of the tilted surfaces from the axial end face becomes smaller from a support recessed surface side toward a circumferential end face side, 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 and the tilted surfaces are not in contact with any of the ridge portion and the side surface portion; and

the central recessed surface has a c

Assignees

• Daido Metal Co

Inventors

• Imamura Akiyoshi
• Suzuki Yu
• Oguri Marina

Classifications

• F01B1/0644 Primary

  Pistons · CPC title

• F01B1/0651

  consisting of several cylindrical elements, e.g. rollers · CPC title

• F02B57/10

  with combustion space in centre of star · CPC title

• F02B75/32

  Engines characterised by connections between pistons and main shafts and not specific to preceding main groups · CPC title

• F02B75/222

  with cylinders in star arrangement · CPC title