Piston ring and compressor

Patent metadata

Field	Value
Publication number	US-11346332-B2
Application number	US-201917046167-A
Country	US
Kind code	B2
Filing date	Apr 8, 2019
Priority date	Apr 27, 2018
Publication date	May 31, 2022
Grant date	May 31, 2022

Abstract

A piston ring includes a first ring portion which is fitted onto an outer circumferential portion of a piston and which is capable of sliding relative to an inner wall surface of a cylinder, and a second ring portion which is fitted onto the outer circumferential portion of the piston, arranged side-by-side with the first ring portion in the axial direction, and which is capable of sliding relative to the inner wall surface of the cylinder. The second ring portion is fitted onto the outer circumferential portion of the piston in such a way as to be positioned on a side opposite to a compression chamber inside the cylinder, relative to the first ring portion, and has a greater hardness than the first ring portion has.

First claim

The invention claimed is:

1. A compressor for a hydrogen station, comprising:
a cylinder having a compression chamber for pressurizing gas;
a piston reciprocating in an axial direction in the cylinder so as to change a volume of the compression chamber; and
a piston ring fitted onto an outer circumferential portion of the piston so as to seal a gap between the outer circumferential portion of the piston and an inner wall surface of the cylinder; the piston ring comprising:
a first ring portion which is fitted onto the outer circumferential portion of the piston and which is capable of sliding relative to the inner wall surface of the cylinder; and
a second ring portion which is fitted onto the outer circumferential portion of the piston, arranged side-by-side with the first ring portion in the axial direction, and which is capable of sliding relative to the inner wall surface of the cylinder,
wherein the second ring portion is fitted onto the outer circumferential portion of the piston in such a way as to be positioned on a side opposite to the compression chamber inside the cylinder, relative to the first ring portion, and has a greater hardness than the first ring portion;
wherein the first ring portion and the second ring portion contain
a main component made of at least one selected from a group consisting of modified polytetrafluoroethylene, polyaryletherketone, polyimide, and polybenzimidazole, and
an additive having a carbonfiller; and

wherein the first ring portion and the second ring portion do not contain sulfur.

2. The compressor according to claim 1 , wherein the first ring portion and the second ring portion are arranged so as to be capable of abutting against each other in a same groove formed so as to be recessed in an orientation away from the inner wall surface of the cylinder on the outer circumferential portion of the piston.

3. The compressor according to claim 2 , wherein the second ring portion includes a plurality of circumferentially divided ring elements each fitted onto the outer circumferential portion of the piston.

4. The compressor according to claim 2 , wherein
the first ring portion is formed with an abutment portion provided by notching a part of a circumferential direction, and
the second ring portion has a portion that overlaps the abutment portion in the axial direction.

5. The compressor according to claim 1 , wherein the second ring portion includes a plurality of circumferentially divided ring elements each fitted onto the outer circumferential portion of the piston.

6. The compressor according to claim 1 , wherein
the first ring portion is formed with an abutment portion provided by notching a part of a circumferential direction, and
the second ring portion has a portion that overlaps the abutment portion in the axial direction.

7. The compressor according to claim 1 , wherein the first ring portion and the second ring portion contain a main component made of at least one selected from a group consisting of polyaryletherketone, polyimide, and polybenzimidazole.

8. The compressor according to claim 1 , wherein
the first ring portion contains a main component made of modified polytetrafluoroethylene, and
the second ring portion contains a main component made of at least one of polyimide and polyetheretherketone.

9. The compressor according to claim 1 , wherein an arithmetic average roughness on the inner wall surface of the cylinder is equal to or less than 0.8.

Assignees

• Kobe Steel Ltd

Inventors

• Kanei Naofumi
• Otsuka Tomohiro
• Ito Hirotaka
• Nii Hiroaki

Classifications

• Y02E60/32

  Hydrogen storage · CPC title

• F16J9/08

  with expansion obtained by pressure of the medium · CPC title

• F04B39/0284

  Constructional details, e.g. reservoirs in the casing (swash-plate compressors F04B27/0878, F04B27/109) · CPC title

• F16J9/16 Primary

  obtained by stacking of rings · CPC title

• F16J9/06

  using separate springs {or elastic elements} expanding the rings; Springs therefor {; Expansion by wedging} · CPC title