Sliding member

Patent metadata

Field	Value
Publication number	US-10422380-B2
Application number	US-201715704197-A
Country	US
Kind code	B2
Filing date	Sep 14, 2017
Priority date	Sep 23, 2016
Publication date	Sep 24, 2019
Grant date	Sep 24, 2019

Abstract

A sliding member includes a sliding layer including graphite particles dispersed in a synthetic resin matrix. The graphite particles have a volume ratio of 5% to 50% and are composed of spheroidal particles and flake-like particles, respectively having a graphitization degree K 1 and K 2 . The flake-like particles have a volume ratio of 10 to 40% with respect to a total volume of the graphite particles. The spheroidal particles have a cross-sectional structure with AB planes of a graphite crystal laminated from a surface toward a center. The flake-like particles have a cross-sectional structure with the AB planes laminated in a thickness direction. The spheroidal particles and the flake-like particles have an average particle size of 3 to 50 μm, and 1 to 25 μm respectively. K 1 is 0.80 to 0.97 and K 2 is greater than K 1 , and a difference K 2 −K 1 is 0.03 to 0.15.

First claim

The invention claimed is:

1. A sliding member comprising:
a back metal layer; and
a sliding layer on the back metal layer, the sliding layer comprising a synthetic resin matrix and graphite particles dispersed in the synthetic resin matrix, the graphite particles having a volume ratio of 5% to 50% of a volume of the sliding layer,
wherein the graphite particles include spheroidal graphite particles having a graphitization degree K 1 and thin plate-shaped flake-like graphite particles having a graphitization degree K 2 , the flake-like graphite particles having a volume ratio of 10% to 40% with respect to a total volume of the graphite particles,
wherein the spheroidal graphite particles have a cross-sectional structure in which a plurality of AB planes of a graphite crystal are laminated, from a particle surface toward a center direction, to have a curved shape along the spherical particle surface,
wherein the flake-like graphite particles have a cross-sectional structure in which the plurality of AB planes of a graphite crystal are laminated in a thickness direction of the thin plate shape,
wherein the spheroidal graphite particles have an average particle size of 3 to 50 μm, and the flake-like graphite particles have an average particle size of 1 to 25 μm, and
wherein the graphitization degree K 1 of the spheroidal graphite particles is 0.80 to 0.97, the graphitization degree K 2 of the flake-like graphite particles is greater than the graphitization degree K 1 of the spheroidal graphite particles, and a difference K 2 −K 1 between the graphitization degree K 2 and the graphitization degree K 1 is 0.03 to 0.15.

2. The sliding member according to claim 1 , wherein the graphitization degree K 1 of the spheroidal graphite particles is 0.85 to 0.97.

3. The sliding member according to claim 1 , wherein the difference K 2 -K 1 is 0.03 to 0.10.

4. The sliding member according to claim 1 , wherein the spheroidal graphite particles have an average aspect ratio of 1.5 to 4.5.

5. The sliding member according to claim 1 , wherein the flake-like graphite particles have an average aspect ratio of 5 to 10, and
wherein an anisotropic dispersion index of the flake-like graphite particles is not less than 3, the anisotropic dispersion index being defined as an average value of a ratio X 1 /Y 1 of each of the flake-like graphite particles, where X 1 is defined as a length of a flake-like graphite particle in a direction parallel to a sliding surface when viewed in a cross-sectional structure perpendicular to the sliding surface of the sliding layer, and
Y 1 is defined as a length of the flake-like graphite particle in a direction perpendicular to the sliding surface when viewed in the cross-sectional structure perpendicular to the sliding surface of the sliding layer.

6. The sliding member according to claim 1 , wherein the synthetic resin matrix is made of one or more synthetic resins selected from a group consisting of PAI, PI, PBI, PA, phenol, epoxy, POM, PEEK, PE, PPS, and PEI.

7. The sliding member according to claim 1 , wherein the sliding layer further comprises 1 to 20 volume % of one or more solid lubricants selected from a group consisting of MoS 2 , WS 2 , h-BN and PTFE.

8. The sliding member according to claim 1 , wherein the sliding layer further comprises 1 to 10 volume % of one or more fillers selected from a group consisting of CaF 2 , CaCO 3 , talc, mica, mullite, iron oxide, calcium phosphate and Mo 2 C.

9. The sliding member according to claim 1 , further comprising a porous metal layer between the back metal layer and the sliding layer.

Assignees

• Daido Metal Co

Inventors

• Yamauchi Takayoshi

Classifications

• C10N2020/06

  Particles of special shape or size · CPC title

• F16C2202/52

  Graphite · CPC title

• F16C2208/40

  Imides, e.g. polyimide [PI], polyetherimide [PEI] (F16C2208/58 takes precedence) · CPC title

• F16C2208/66

  Acetals, e.g. polyoxymethylene [POM] · CPC title

• F16C2208/32

  Polytetrafluorethylene [PTFE] (F16C2208/58 takes precedence) · CPC title