| 摘要 |
<p>PURPOSE:To provide a high-frequency hardening method of a rack shaft which decreases hardening strains, improves the bending fatigue strength of teeth and improves productivity. CONSTITUTION:Hardened layers are simultaneously formed on the tooth faces and rear surfaces of the tooth parts of the rack shaft by high-frequency hardening, by which the hardening volume on the tooth face side and the hardening volume on the rear surface side facing the tooth faces are nearly equaled. The range from the tooth parts to the shaft part on the tooth surface side of the rack shaft to the range from the rear surfaces of the tooth parts on the rear surface side to the shaft part are simultaneously subjected to the high-frequency hardening. The hardened layers of the equal volume are simultaneously formed on the tooth faces and rear surfaces of the tooth parts of the rack shaft are formed and, therefore, the rack shaft having the good accuracy and decreased hardening strains is obtd. The uncured parts at the boundaries of the tooth parts and the shaft part are eliminated by executing integral hardening and, therefore, the accuracy is improved. Since the strength is imparted to the tooth surfaces and the wear resistance to the shaft part by one time of stage, the productivity is improved.</p> |
