Automotive engine valve mechanism system shim and lifter of these and cam shaft
US7086362B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 27, 2002 |
| Grant date | Aug 8, 2006 |
| Priority date | — |
| Expiry date | Mar 5, 2024 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF01L2820/01
- WIPO fieldEngines, pumps, turbines
- WIPO sectorMechanical engineering
Abstract
Disclosed is a shim or a valve lifter for an automotive engine valve driving system that slides against a cam lobe of a camshaft to drive an intake/exhaust valve of an internal combustion engine. The shim or lifter has the top of a sliding surface thereof opposing the cam lobe and being coated with a hard carbon film. The hard carbon film has a surface hardness of 1500 to 4500 kg/mm2 in terms of Knoop hardness, a thickness of 0.3 to 2.0 μm and a surface roughness Ry (μm) satisfying the following equation (A):Ry<{(0.75−Hk/8000)×h+0.07/0.8} (A)where h is the thickness (μm) of the hard carbon film; and Hk is the knoop hardness (kg/mm2) of the hard carbon film. By imparting durability, reliability and a low friction coefficient to the hard carbon film that is said to be low in ductility to prevent the hard carbon film from becoming cracked and separated when applied to the sliding portion.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.