Ntn Corporation

Tomonori Yamashita

Yoshinori Ito

Takashi Yamaguchi

Takehiro Matsuzuki

Yuta Ohashi

Daisuke Takeda

Provided is a sintered bearing formed mainly of an iron structure () and a copper structure () which are formed of a partially diffusion-alloyed powder () of an iron powder () and a copper powder (). The sintered bearing includes a copper structure () formed of a granular elemental copper powder (') having a grain diameter of 45 μm or less, the ratio of the copper structure () being 10 mass % or less. With this, a further increase in strength of the sintered bearing can be realized.

Sintered bearing and method of manufacturing same

A sintered metal connecting rod () includes as an integrated body, a large end portion (), a small end portion (), and a stem portion (). In the sintered metal connecting rod (), division marks () of a molding die by a compression molding are formed between the large end portion () and the stem portion () and between the small end portion () and the stem portion () on one of front and back surface (to) in which the through-holes () are formed, respectively. The large end portion () and the stem portion () have a density difference of 4% or less, and the small end portion () and the stem portion () have a density difference of 4% or less.

Sintered metal connecting rod

A sintered bearing includes, on an inner peripheral surface, a cylindrical portion and a one-side increased-diameter portion, which are provided so as to be continuous in the axial direction. An end portion of one side in the axial direction of the cylindrical portion and an end portion of another side in the axial direction of the increased-diameter portion coincide, and the cylindrical portion and the increased-diameter portion are molded by performing sizing on a sintered compact having a tubular shape, which is introduced into a die.

Sintered bearing

A sintered bearing () contains as main components iron, copper, a metal having a lower melting point than copper, and a solid lubricant. The sintered bearing () includes a surface layer (S) and a base part (S). The surface layer (S) is formed mainly of flat copper powder arranged so as to be thinned in a thickness direction. In the base part (S), an iron structure () and a copper structure () brought into contact with the iron structure are formed of partially diffusion-alloyed powder in which copper powder is partially diffused in iron powder. Thus, a sintered bearing which achieves a balance between wear resistance of a bearing surface and strength of the bearing, and realizes low cost can be provided.

Sintered bearing and manufacturing process therefor

A connecting rod module () includes: a connecting rod (), which is formed of a sintered metal; and bearing raceway rings (outer rings ()), which are press-fitted into a through-hole (), respectively. The connecting rod () has a Young's modulus of from 120 GPa or more to 180 GPa or less. The outer rings () each have a Young's modulus of from more than 180 GPa to 240 Gpa or less. When T represents a radial thickness of each of the outer rings (), D represents an inner diameter dimension of each of the through-holes (), and I represents an interference between the outer ring () and a peripheral wall of the through-hole () or between the outer ring () and a peripheral wall of the through-hole (), the following equations are established:=(0.05&#x2dc;0.15)&#xd7;; and=(0.0004&#x2dc;0.004)&#xd7;

Connecting rod module

A connecting rod module () includes: a connecting rod (), which is formed of a sintered metal; and bearing raceway rings (outer rings ()), which are press-fitted into a through-hole (), respectively. The connecting rod () has a Young's modulus of from 120 GPa or more to 180 GPa or less. The outer rings () each have a Young's modulus of from more than 180 GPa to 240 GPa or less. When T represents a radial thickness of each of the outer rings (), D represents an inner diameter dimension of each of the through-holes (), and I represents an interference between the outer ring () and a peripheral wall of the through-hole () or between the outer ring () and a peripheral wall of the through-hole (), the following equations are established: T=(0.05&#x2dc;0.15)&#xd7;D; and I=(0.0004&#x2dc;0.004)&#xd7;D.

Method of manufacturing connecting rod module

A sintered bearing includes a cylindrical portion, one-side increased-diameter portion and another-side increased-diameter portion. A metal structure of the another-side increased-diameter portion has a higher density than a metal structure of a core portion of the sintered compact. A metal structure of the cylindrical portion has an expansion along a direction of ironing by the sizing core and a higher density than the metal structure of the another-side increased-diameter portion. A metal structure of the one-side increased-diameter portion has an expansion along a direction of ironing by the sizing core and a higher density than the metal structure of the cylindrical portion.

Growing community of inventors

Aichi, Japan

Tomonori Yamashita