US 11,248,654 B2 · Oil impregnated sintered bearing and production method thereof

Abstract

On an inner peripheral surface of a bearing hole into which a shaft is inserted, concave oil supply surfaces arranged dispersively like separated islands and a sliding surface continuous around the oil supply surfaces to hold an outer peripheral surface of the shaft are formed: a maximum height difference between the sliding surface and the oil supply surfaces is not less than 0.01% and not more than 0.5% of an inner diameter Di of the sliding surface; a surface aperture area ratio of pores at the sliding surface is not more than 10%; a surface aperture area ratio of pores at the oil supply surfaces is more than 10% and less than 40%; and an area of each of the oil supply surfaces is not less than 0.03 mm2 and not more than 0.2×Di2 (mm2).

Claims16

Dependent claims

An oil impregnated sintered bearing made of a porous body with pores, having a bearing hole into which a shaft is inserted, comprising:

concave oil supply surfaces formed at an inner peripheral surface of the bearing hole and dispersed throughout the inner peripheral surface, and
a sliding surface with an inner diameter Di formed on the inner peripheral surface of the bearing hole to be continuous around the oil supply surfaces and holding an outer peripheral surface of the shaft, wherein
the oil is exuded from the pores,
a maximum height difference between the sliding surface and the oil supply surface is not less than 0.01% and not more than 0.5% of the inner diameter Di,
a surface aperture area ratio of the pores at the sliding surface is not less than 0% and not more than 10% and a surface aperture area ratio of the pores at the oil supply surfaces is more than 10% and less than 40%, and
each of the oil supply surfaces has an area of not less than 0.03 (mm2) and not more 0.2×Di2 (mm2).

3 more elements

A method of manufacturing an oil impregnated sintered bearing comprising:

a step of forming green compact, forming a cylindrical green compact by filling material powder into a cylindrical space between a forming die plate and a forming core rod of a forming die and pressurizing,
a step of sintering, forming a sintered body by sintering the green compact, and
a step of sizing, correcting dimensions of the sintered body and forming a bearing hole by pushing and pressurizing the sintered body into a cylindrical space between a sizing die plate and a sizing core rod of a sizing die, wherein
in the step of forming the green compact, protruded parts are formed on at least a part of an outer peripheral surface of the forming core rod so as to protrude from the other part outward in a radial direction, concave parts and a convex part adjacent and continuous to the concave parts are formed on an inner peripheral surface of the green compact, said concave parts being dispersed throughout the inner peripheral surface,
in the step of sintering, the concave parts are formed into oil supply surfaces having pores through which oil is exuded and a surface aperture area ratio of more than 10% by sintering the pressured powder body, and
in the step of sizing, an outer peripheral surface of the sizing core rod is formed to be larger than an inner diameter of the convex part of the sintered body and smaller than an inner diameter of the concave parts;
a sliding surface having a surface aperture area ratio of not less than 0% and not more than 10% is formed by compressing the convex part outward in a radial direction by the outer peripheral surface of the sizing core rod;
a maximum height difference between the oil supply surfaces and the sliding surface is formed to be not less than 0.01% and not more than 0.5% of an inner diameter of the sliding surface;
and an area of each of the oil supply surfaces is made to be not less than 0.03 (mm2) and not more than 0.2×Di2 (mm2) to an inner diameter Di of the bearing hole.

6 more elements

Dependencies are inferred from the claim text.

Oil impregnated sintered bearing and production method thereof

Life of this patent

Oil impregnated sintered bearing and production method thereof

Life of this patent

Abstract

Claims16