| 摘要 |
<p>Provided is a heat treatment method by which it is possible to form an outside connecting member of a tripod-type constant velocity universal joint having an excellent strength by continuous high-frequency hardening without forming a hardened layer at the large-inner-diameter section. Also provided are an outside connecting member and a tripod-type constant velocity universal joint formed using the heat treatment method of such description. A heat treatment device performs continuous hardening, in which a high-frequency induction heating coil (56) is moved axially with respect to the outside joint member (31). The outside joint member (31) has track grooves (36), comprising roller guide surfaces (37, 37) which face each other in the circumferential direction and a large-diameter section (43) provided between the roller guide surfaces, formed in three locations of the inner circumference. In the continuous hardening, a hardened layer (S) is formed on the roller guide surfaces (37, 37) of the outside joint member (31). The heat treatment device is provided with a large-inner-diameter-section cooling means (M1) for discharging water onto the large-diameter section (43) and suppressing the temperature increase of the large-diameter section (43).</p> |
