Piston ring
US5154433A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 14, 1991 |
| Grant date | Oct 13, 1992 |
| Priority date | — |
| Expiry date | Jun 14, 2011 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF16J9/26
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
A piston ring comprises a martensitic stainless steel ring having a nitrided layer formed in the surface portion thereof, and a titanium nitride film coated on the outer sliding surface of the ring by an ion-plating process. According to a first embodiment of the present invention, the titanium nitride film has a nitrogen concentration which is gradually increased toward the top surface thereof to gradually lower a toughness of the film toward the top surface and to make a surface portion of the film more brittle than the other portion of the film. On the other hand, according to a second embodiment of the present invention, the titanium nitride film has a nitrogen concentration which is gradually decreased toward the top surface and to make a surface hardness of the film HV 1800 or less.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.