Power transmission shaft
AssigneeNtn Corporation
InventorsKazuhiko Yoshida, Hiroaki Makino, Akira Wakita
Life of this patent
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Abstract
The power transmission shaft 12 is made by applying induction hardening to carbon steel with hardening ratio in a range from 0.25 to 0.50. For the carbon steel, one containing 0.39 to 0.49% of C, 0.4 to 1.5% of Si, 0.4 to 1.0% of Mn, 0.025% or less S, 0.02% or less P and 0.01 to 0.1% of Al by weight as the basic components, with the rest comprising Fe and inevitable impurities is used. This makes it possible to achieve higher strength and lighter weight of the power transmission shaft.
Claims4
A power transmission shaft, used in a constant velocity joint, said shaft having an induction-hardened smooth-surfaced portion and an induction-hardened torque transmitting teeth portion, wherein effective depth of hardened layer of the smooth-surfaced portion having the least diameter is set to be greater than the effective depth of hardened layer of a minor diameter portion of the torque transmitting teeth portion and wherein the core of the smooth-surfaced portion of the least diameter has a structure including ferrite and martensite and an effect of heat is caused to reach the core.
Dependencies are inferred from the claim text.