Claims
- 1. A shim for a tappet in an internal combustion engine having a cam which rotates with the engine, comprising;
- a shim member mounted on the tappet and having a contact surface thereon for slidably contacting the cam, the contact surface having a central area and a second area surrounding the central area;
- the shim having a plurality of bores on the contact surface, the density of the bores in the central area being higher than the density of the bores in the surrounding second area.
- 2. A shim as defined in claim 1 wherein an opening area of the bore at the contact surface of the shim is 0.1 to 50000 .mu.m.sup.2.
- 3. A shim as defined in claim 1 wherein lubricating solid material is filled in at least some of the bores.
- 4. A shim as defined in claim 3 wherein the lubricating solid material is filled in said bores so that an upper surface of the solid material is substantially as high as the contact surface of the shim.
- 5. A shim as defined in claim 3 wherein the lubricating solid material comprises molybdenum disulfide.
- 6. A shim as defined in claim 3 wherein the lubricating solid material comprises polyethylene.
- 7. A shim as defined in claim 1 wherein at least some of said bores are formed as hemispheres.
- 8. A shim as defined in claim 3 wherein at least some of said bores have a first diameter at the contact surface and a second diameter remote from the contact surface of the shim, the second diameter being larger than the first diameter, thereby impeding the solid material from escaping from the bores.
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of U.S. patent application Ser. No. 08/539,324, filed Oct. 4, 1995, now abandoned, which is a continuation-in-part of Ser. No. 08/386,300 (now abandoned) filed Feb. 8, 1995.
US Referenced Citations (6)
Continuation in Parts (2)
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Number |
Date |
Country |
Parent |
539324 |
Oct 1995 |
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Parent |
386300 |
Feb 1995 |
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