| 摘要 |
PROBLEM TO BE SOLVED: To provide an outside joint member for a constant-velocity universal joint and a fixed type constant-velocity universal joint in which both properties of statistic torsional strength and torsional fatigue strength of a mouth portion can be improved without generating a hardening crack in a hardened portion of a truck opening end, at low cost with no decrease involved in operational angle. SOLUTION: An outside joint member has a mouth portion 27 whose inner diametral surface is formed with a track groove 31 whose backside and opening side are formed into a circular-arc shaped portion 31a and a linear portion 31b, respectively. The mouth portion 27 is processed by a cold forging operation and an outer circumferential side of the mouth portion 27 is made to be 280Hv or more and 400Hv or less in hardness. A hardened layer H1 is formed in an inner surface of the track groove 31 of the mouth portion 27. The hardened layer is made to be 500 Hv or more and 780 Hv or less in hardness. A chamfer 44 is formed in the mouth portion 27. There is provided a tilted portion 45 which tilts from an opening edge of the track groove 31 to the opening side and further to an outer diametral side to reach an opening end surface of the mouth portion 27. Thickness of the hardened layer of an opening end in the track groove 31 is made to be 1 to 25% of that of mouth portion. Besides, thickness of the hardened layer in a portion corresponding to a boots mounted portion 40 is made to be 20 to 55% of that of mouth portion. COPYRIGHT: (C)2009,JPO&INPIT
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