Patent ID: 7604304

Claim:
A crawler comprising: a cylindrical crawler bushing, which is surface-hardened on its outer circumference to form a hardened layer, wherein the hardened layer is hardened to a hardness of HRC 50 or more by induction heating and quenching from the outer surface of the bushing; a crawler pin arranged on the inner circumference of said crawler bushing; a clearance provided between said crawler bushing and said crawler pin; and a metal member that is separate from said crawler bushing and said crawler pin and arranged in the clearance between said crawler bushing and said crawler pin, said metal member including at least one layer, wherein: said at least one layer of said metal member is a metallic sliding member having perforations holding lubricating oil and/or a lubricant in widthwise directions, the perforations having a length extending through the metallic sliding member and having openings facing the crawler bushing and the crawler pin, said metallic sliding member is made of copper sintered sliding material, and said copper sintered sliding material is a Cu—Al—Ti based sintered sliding material prepared by compression-molding and sintering the mixed powder for the copper sintered material, as containing essentially 5 to 12 wt % of Al and at least 0.3 to 5 wt % of Ti, and by repeating the steps of compressing and sintering the sintered material obtained, one or more times, an inner surface of the bushing and the metallic sliding member are integrated by caulking, press-fitting, or adhering, a seal device is fitted to an inner surface of the bushing at or near an end of the bushing, and a part of the inner surface of the bushing where the metallic sliding member is integrated with the bushing and where the seal device is fitted to the bushing is relatively softer than the hardened layer and has a hardness that is less than HRC 50.