Sliding bearing

Details Sliding bearing Sliding bearing

1996-10-07

1998-10-06

Watkins, III, William P.

Stock material or miscellaneous articles

Structurally defined web or sheet

Continuous and nonuniform or irregular surface on layer or...

428600, 428646, 428687, 428156, 428161, 428162, 428164, 428172, 428173, 428213, 428215, 428925, 428926, 428648, 428612, 384283, 384284, 384285, 384282, 384912, 384913, F16C 3308, B32B 328

Patent

active

058173978

DESCRIPTION:

BRIEF SUMMARY
FIELD OF THE INVENTION

The invention relates to a sliding bearing, and more particularly, to a sliding bearing which is used in an internal combustion engine.


BACKGROUND

A sliding bearing is known in the art which includes a lining member having a multiplicity of uneven surfaces formed on its surface, and in which the entire surface of the lining member, inclusive of the uneven surfaces, is coated by an intermediate layer, and the entire surface of the lining member which is coated by the intermediate layer is then additionally coated by a overlay layer, wherein recesses within the uneven surfaces are filled by an overlay layer so that when the overlay layer and the intermediate layer become abraded, the exposed surface contains the exposed lining member, the exposed intermediate layer which coats the recesses within the uneven surfaces and the exposed overlay layer which is applied to the recesses within the uneven surfaces (See, for example Japanese Laid-Open Patent Application No. 38,714/90).
In the conventional sliding bearing described above, when the overlay layer comprises Sn and the intermediate layer comprises Ni, for example, as the sliding bearing is heated by heat from the engine, Sn in the overlay layer and Ni in the intermediate layer chemically react with each other to produce an Ni--Sn compound. In the conventional sliding bearing, no consideration has been paid to the relationship between the thickness of the intermediate layer and the roughness of the uneven surfaces. Accordingly, subsequent to the formation of Ni--Sn compound, as the overlay layer which is located on the surface side thereof becomes gradually abraded, the Ni--Sn compound becomes exposed across the entire sliding surface of the sliding bearing, causing a disadvantage in that the anti-seizure resistance of the sliding bearing becomes rapidly degraded.
As a result of a study made by the present inventor concerning the relationship between the thickness of the intermediate layer and the surface roughness of the uneven surfaces, it is found that in the example given above, an Sn--Ni compound, which is found when the sliding bearing becomes heated, has a thickness which is from about twice to thrice the thickness of the intermediate layer. Accordingly, in accordance with the invention, the roughness (depth) of the uneven surfaces is chosen to be thrice the thickness of the intermediate layer or greater, so that if the Ni--Sn compound is produced as mentioned, the exposure of the Ni--Sn compound across the entire sliding surface can be prevented.
More specifically, the invention relates to a sliding bearing in which the surface of a lining member is formed with a multiplicity of uneven surfaces, the entire surface of the lining member, inclusive of the uneven surfaces, is coated by an intermediate layer, and the entire surface of the lining member which is coated by the intermediate layer is additionally coated by an overlay layer. Recesses within the uneven surfaces are filled by an overlay layer, so that when the overlay layer and the intermediate layer become abraded, the exposed surface contains the exposed lining member, the exposed intermediate layer which coats recesses within the uneven surfaces, and the exposed overlay layer which is located within the recesses in the uneven surfaces. In accordance with the invention, the thickness of the intermediate layer is chosen to be in a range from 0.01 to 0.6 .mu.m, and the surface roughness of the lining member which results from forming the uneven surfaces is chosen to be in a range from 2 to 8 .mu.mRz.
With this construction, when the Ni--Sn compound is produced as a result of heating of the intermediate layer and the overlay layer, the roughness (depth) of the uneven surfaces measures thrice the thickness of the intermediate layer, or greater, and accordingly, as the overlay layer becomes gradually abraded, the overlay layer remains within recesses located within the uneven surfaces, thus effectively preventing the exposure of the Ni--Sn compound across the entire slidi

REFERENCES:
patent: 4718155 (1988-01-01), Warriner et al.

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