Sliding bearing for an internal combustion engine

Abstract

A sliding bearing for an internal combustion engine; the sliding bearing having a groove formed substantially circumferentially on an inner circumferential face of the sliding bearing; the width of the groove being smaller than 0.6 mm, and the ratio of the width of the groove to depth of the groove being larger than 40.

We claim:  
     
       1. A sliding bearing for an internal combustion engine; said sliding bearing having a groove formed substantially circumferentially on an inner circumferential face of said sliding bearing; the width of said groove being smaller than 0.6 mm, a  depth of the groove being less than  3  μm  and the ratio of said width of said groove to  the  depth of said groove being larger than 40. 
     
     
       2. A sliding bearing according to  claim 1 , wherein said ratio is smaller than 200. 
     
     
       3. A sliding bearing according to  claim 1 , wherein said groove is formed over an entire inner circumferential face of said sliding bearing. 
     
     
       4. A sliding bearing according to  claim 1 , wherein said groove is a spiral groove. 
     
     
       5. A sliding bearing according to  claim 1 , wherein said groove is formed at less than 1° to a rotational direction of a crank shaft. 
     
     
       6. A sliding bearing according to  claim 1 , wherein kelmet is used as a bearing metal, and said groove is formed on a bearing surface of said kelmet. 
     
     
       7. A sliding bearing according to  claim 6 , wherein a nickel plating layer is formed on said bearing surface of said kelmet, and a lead alloy plating layer is formed on said nickel plating layer. 
     
     
       8. A sliding bearing according to  claim 7 , wherein the thickness of said nickel plating layer is 1-3 μm. 
     
     
       9. A sliding bearing according to  claim 1 , wherein an aluminum alloy is used as a bearing metal, and said groove is formed on a bearing surface of said aluminum alloy. 
     
     
       10. A sliding bearing according to  claim 9 , wherein a nickel plating layer is formed on said bearing surface of said aluminum alloy, and a lead alloy plating layer is formed on said nickel plating layer. 
     
     
       11. A sliding bearing according to  claim 10 , wherein a thickness of said nickel plating layer is 0.1-2.0 μm. 
     
     
       12. A sliding bearing according to  claim 1 , wherein the width of the groove is smaller than about  0 . 4  mm.  
     
     
       13. A sliding bearing according to  claim 12 , wherein the width of the groove is greater than  0 . 15  mm.  
     
     
       14. A sliding bearing according to  claim 1 , wherein the width of the groove is greater than  0 . 15  mm.  
     
     
       15. A sliding bearing according to  claim 1 , wherein the ratio is smaller than  100 .  
     
     
       16. A sliding bearing according to  claim 1 , wherein the ratio is between  43  and  100 .  
     
     
       17. An internal combustion engine including a plurality of the sliding bearings according to  claim 1 .  
     
     
       18. A sliding bearing for an internal combustion engine; the sliding bearing having a groove formed substantially circumferentially on an inner circumferential face of the sliding bearing; the width of the groove being smaller than  0 . 6  mm, a depth of the groove being in the range from  1 . 5  μm to  2 . 5  μm and the ratio of the width of the groove to the depth of the groove being larger than  40 .  
     
     
       19. A sliding bearing according to  claim 18 , wherein the ratio is smaller than  200 .  
     
     
       20. A sliding bearing according to  claim 18 , wherein the groove is formed over an entire inner circumferential face of the sliding bearing.  
     
     
       21. A sliding bearing according to  claim 18 , wherein the groove is a spiral groove.  
     
     
       22. A sliding bearing according to  claim 18 , wherein the groove is formed at less than  1 ° to a rotational direction of a crank shaft.  
     
     
       23. A sliding bearing according to  claim 18 , wherein kelmet is used as a bearing metal, and the groove is formed on a bearing surface of the kelmet.  
     
     
       24. A sliding bearing according to  claim 23 , wherein a nickel plating layer is formed on the bearing surface of the kelmet, and a lead alloy plating layer is formed on the nickel plating layer.  
     
     
       25. A sliding bearing according to  claim 24 , wherein the thickness of the nickel plating layer is  1 - 3  μm.  
     
     
       26. A sliding bearing according to  claim 18 , wherein an aluminum alloy is used as a bearing metal, and the groove is formed on a bearing surface of the aluminum alloy.  
     
     
       27. A sliding bearing according to  claim 26 , wherein a nickel plating layer is formed on the bearing surface of the aluminum alloy, and a lead alloy plating layer is formed on the nickel plating layer.  
     
     
       28. A sliding bearing according to  claim 27 , wherein a thickness of the nickel plating layer is  0 . 1 - 2 . 0  μm.  
     
     
       29. A sliding bearing according to  claim 18 , wherein the width of the groove is smaller than about  0 . 4  mm.  
     
     
       30. A sliding bearing according to  claim 29 , wherein the width of the groove is greater than  0 . 15  mm.  
     
     
       31. A sliding bearing according to  claim 18 , wherein the width of the groove is greater than  0 . 15  mm.  
     
     
       32. A sliding bearing according to  claim 18 , wherein the ratio is smaller than  100 .  
     
     
       33. An internal combustion engine including a plurality of the sliding bearings according to  claim 18 .