EP-4741689-A1 - SLIDING COMPONENT

Abstract

Provided are sliding components capable of maintaining low friction properties. Sliding components includes a pair of sliding rings 10 and 20 having sliding surfaces 11 and 21 which rotate relative to each other to define an outer radial space S1 and an inner radial space S2, the sliding surface 11 is provided with a circumferential groove 14 extending in a circumferential direction and a recess 18 communicating with the circumferential groove 14, and the circumferential groove 14 has a throttled opening portion AA in close vicinity to the sliding surface 11.

Inventors

• HOSOI KAZUYA
• FUKUHARA Takuto
• YANO YUKI

Assignees

• Eagle Industry Co., Ltd.

Dates

Publication Date

20260513

Application Date

20240701

Claims (8)

1. Sliding components comprising a pair of sliding rings having sliding surfaces which rotate relative to each other to define an outer radial space and an inner radial space of the sliding rings, wherein the sliding surface of one of the sliding rings is provided with a circumferential groove extending in a circumferential direction and a recess communicating with the circumferential groove, and wherein the circumferential groove has a throttled opening portion in close vicinity to the sliding surface of the one of the sliding rings.
2. The sliding components according to claim 1, wherein the throttled opening portion is defined by both side walls of the circumferential groove projecting in a radial direction.
3. The sliding components according to claim 1, wherein the circumferential groove has a dovetail shape in which both side walls of the circumferential groove are inclined with respect to an axial direction.
4. The sliding components according to claim 1, wherein the recess is formed to be deeper than the circumferential groove.
5. The sliding components according to claim 1, wherein the recess has a throttled opening portion on the side of the sliding surface.
6. The sliding components according to claim 1, wherein the recess is formed at a plurality of positions along the circumferential groove extending in a circumferential direction.
7. The sliding components according to claim 1, wherein the circumferential groove is formed in a plurality of radial stripes at a predetermined pitch, and wherein a maximum radial width of the recess is equal to or larger than half the predetermined pitch of the circumferential grooves.
8. The sliding components according to any one of claims 1 to 7, wherein the sliding components are formed of SiC.

Description

{TECHNICAL FIELD} The present invention relates to sliding components, for example, sliding components used in a shaft seal or a bearing. {BACKGROUND ART} As sliding components for preventing leakage of a sealed fluid around a rotating shaft in a rotary machine, for example, a mechanical seal consisting of a pair of annular sliding rings that rotate relative to each other and have sliding surfaces that slide against each other is known. In such mechanical seals, it is desirable to reduce the amount of energy lost due to sliding for environmental measures and the like, and some mechanical seals have a structure aimed at ensuring low friction properties on the sliding surface of the sliding ring. For example, one is described in Patent Citation 1 as below. The sliding surface of one of the sliding components of the mechanical seal is provided with a plurality of minute concave portions provided at a predetermined pitch width, and a deep groove that is provided across the plurality of concave portions and is deeper than the concave portions. When a pair of sliding components rotate relative to each other, a curved convex portion which is a top portion between concave portions slides against the other sliding surface to generate fine wear products, and the fine wear products adhere between the convex portion and the other sliding surface to form a transfer layer and are also collected in the concave portion. The transfer layer promotes the transition from severe wear to mild wear between the sliding surfaces during relative rotation. Further, the excess wear products are discharged into the deep grooves. {CITATION LIST} {Patent Literature} Patent Citation 1: JP 2019-108921 A (Page 5, FIG. 1) {SUMMARY OF INVENTION} {Technical Problem} In the sliding components of Patent Citation 1, as the sliding surfaces break in due to sliding, wear products are accumulated and retained in the recesses of the periodic structure, thereby ensuring low friction properties between the sliding surfaces. However, since a radial flow occurs in the fluid between the sliding surfaces due to the pressure difference between the inner radial side and the outer radial side of the sliding components and the centrifugal force acting on the fluid between the sliding surfaces, it is easy for fine wear products to be discharged from the concave portions, and there is a risk that the wear products returning between the sliding surfaces will hinder the maintenance of low friction properties. The present invention has been made in view of such problems and an object thereof is to provide sliding components capable of maintaining low friction properties. {Solution to Problem} In order to solve the above-described problems, sliding components according to the present invention are sliding components comprising a pair of sliding rings having sliding surfaces which rotate relative to each other to define an outer radial space and an inner radial space of the sliding rings, wherein the sliding surface of one of the sliding rings is provided with a circumferential groove extending in a circumferential direction and a recess communicating with the circumferential groove, and wherein the circumferential groove has a throttled opening portion in close vicinity to the sliding surface of the one of the sliding rings. According to the aforesaid feature of the present invention, the wear products generated by the wear of the sliding components are collected in the circumferential groove, and the movement of the collected wear products is hindered by the throttled opening portion, so that the wear products are less likely to be discharged particularly in the radial direction, and the wear products are retained in the circumferential groove and the recess communicating with the circumferential groove to maintain low friction properties. It may be preferable that the throttled opening portion is defined by both side walls of the circumferential groove projecting in a radial direction. According to this preferable configuration, the wear products collected in the circumferential groove are less likely to be discharged to both radial sides. It may be preferable that the circumferential groove has a dovetail shape in which both side walls of the circumferential groove are inclined with respect to an axial direction. According to this preferable configuration, since the throttled opening portion is formed by the inclination, a large volume can be formed on the bottom portion side of the circumferential groove, and the wear products can be efficiently collected. It may be preferable that the recess is formed to be deeper than the circumferential groove. According to this preferable configuration, the wear products accumulated in the recesses are less likely to be discharged to the outside due to relative sliding of the sliding surfaces. It may be preferable that the recess has a throttled opening portion on the side of the sliding surface. According to this preferable