Crawler, crawler pin, crawler bush, and crawler manufacturing method

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 separate metal member including at least one layer and being arranged in the clearance between said crawler bushing and said crawler pin, 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 a copper sintered sliding material having a lower Young's modulus than that of steel and having properties of seizure resistance, wear resistance and corrosion resistance,
• 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, which contains 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,
• said metallic sliding member has 5 to 30 volume percentage of pores, which are impregnated with the lubricating oil,
• 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.

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 separate metal member including at least one layer and being arranged in the clearance between said crawler bushing and said crawler pin, wherein
• said at least one layer of said metal member is a metallic sliding member having a structure capable of holding lubricating oil and/or a lubricant,
• said metallic sliding member is a copper sintered sliding material having a lower Young's modulus than that of steel and having properties of seizure resistance, wear resistance and corrosion resistance,
• said copper sintered sliding material is a Cu—Al—Sn based sintered sliding material which contains 5 to 12 wt % of Al, 3 to 6 wt % of Sn, and at least 0.5 to 5.0 wt % of at least one of Ti, Ni, Co, Si, Fe and P,
• 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.

A crawler comprising:

• 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 separate metal member including at least one layer and being arranged in the clearance between said crawler bushing and said crawler pin, wherein
• said at least one layer of said metal member is a metallic sliding member having a structure capable of holding lubricating oil and/or a lubricant,
• said metallic sliding member is a copper sintered sliding material having a lower Young's modulus than that of steel and having properties of seizure resistance, wear resistance and corrosion resistance,
• said copper sintered sliding material is a Cu—Al—Sn based sintered sliding material which contains 5 to 12 wt % of Al, 3 to 6 wt % of Sn, and at least 0.5 to 5.0 wt % of at least one of Ti, Ni, Co, Si, Fe and P, and said metallic sliding member has 5 to 30 volume percentage of pores, which are impregnated with the lubricating oil,
• 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.

A multi-layered crawler bushing constructing a crawler including:

• 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 separate metal member including at least one layer and being arranged in the clearance between said crawler bushing and said crawler pin, said at least one layer of said metal member being 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 member and having openings facing the crawler bushing and the crawler pin, wherein
• the metallic sliding member has a structure in which at least its outer circumference is hardened to HRC50 or higher, has at least one layer on its inner circumference for storing lubricating oil and/or a lubricant, and is integrated with an inner surface of the bushing by caulking, press-fitting or adhering, and
• said copper sintered sliding material is a Cu—Al—Ti based sintered sliding material prepared by compression-molding and sintering a mixed powder for the copper sintered material, which contains 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,
• 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.

A multi-layered crawler bushing constructing a crawler including:

• 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 separate metal member including at least one layer and being arranged in the clearance formed between said crawler bushing and said crawler pin, said at least one layer of said metal member being a metallic sliding member having a structure capable of holding lubricating oil and/or a lubricant, wherein
• the metallic sliding member has a structure in which at least its outer circumference is hardened to HRC50 or higher, has at least one layer on its inner circumference for storing lubricating oil and/or a lubricant, and is integrated with an inner surface of the bushing by caulking, press-fitting or adhering,
• said copper sintered sliding material is a Cu—Al—Sn based sintered sliding material, which contains 5 to 12 wt % of Al and at least 3 to 6 wt % of Sn, and at least 0.5 to 5.0 wt % of at least one of Ti, Ni, Co, Si, Fe and P,
• 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.

A method for manufacturing a crawler including:

• 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 separate metal member including at least one layer and being arranged in the clearance between said crawler bushing and said crawler pin, said at least one layer of said metal member being 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 member and having openings facing the crawler bushing and the crawler pin;
• wherein
• the metallic sliding member has a structure in which at least its outer surface is hardened to HRC50 or higher, or in which a range of surfaces of end faces of the metallic sliding member within a range of a distance of one half or more of the thickness from the outer circumference is hardened to HRC50 or higher,
• the metallic sliding member is integrated with the inner circumference of said crawler bushing by caulking, press-fitting or adhering, and
• said copper sintered sliding material is a Cu—Al—Ti based sintered sliding material that is prepared by compression-molding and sintering a mixed powder for the copper sintered material, which contains 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,
• 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.

A method for manufacturing a crawler including:

• 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 separate metal member including at least one layer and being arranged in the clearance between said crawler bushing and said crawler pin, said at least one layer of said metal member being a metallic sliding member having a structure capable of holding lubricating oil and/or a lubricant, wherein
• the metallic sliding member has a structure in which at least its outer surface is hardened to HRC50 or higher, or in which a range of surfaces of end faces of the metallic sliding member within a range of a distance of one half or more of the thickness from the outer circumference is hardened to HRC50 or higher,
• the metallic sliding member is integrated with the inner circumference of said crawler bushing by caulking, press-fitting or adhering, and
• said copper sintered sliding material is a Cu—Al—Sn based sintered sliding material which contains 5 to 12 wt % of Al and at least 3 to 6 wt % of Sn, and at least 0.5 to 5.0 wt % of at least one of Ti, Ni, Co, Si, Fe and P,
• 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.