Patent ID: 8673092
Filing Date: 2014-03-18
Classification: B23K,C21D,F16D,Y02P

Abstract:
1. An outer member of a constant velocity universal joint, the outer member comprising: a cup-section-side forming part including a cup section having a plurality of track grooves formed therein; and a shaft-section-side forming part including a shaft section having one end coupled to a bottom portion of the cup section, wherein the cup-section-side forming part and the shaft-section-side forming part are friction welded together, the cup-section-side forming part and the shaft-section-side forming part have different carbon content, one of the cup-section-side forming part and the shaft-section-side forming part having a high carbon content has a carbon content of 0.45 mass % to 0.58 mass %, and another of the cup-section-side forming part and the shaft-section-side forming part having a low carbon content has a carbon content of 0.35 mass % to 0.46 mass %, the friction welded cup-section-side forming part and shaft-section-side forming part include an induction hardened layer, a hardening heat-affected portion affected by induction hardening, a hardening heat-unaffected portion unaffected by the induction hardening, a joining heat-affected portion affected by heat generated at a time of friction welding, and a joining heat-unaffected portion unaffected by the heat generated at the time of the friction welding, and the one of the cup-section-side forming part and the shaft-section-side forming part having the high carbon content has an end portion with a joining end surface that is joined to the other of the cup-section-side forming part and the shaft-section-side forming part having the low carbon content, the hardening heat-unaffected portion at the end portion being free from a martensitic structure and the joining heat-affected portion being at the end portion.