| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a torsional damper assuring good weldability and high-frequency hardenability without subjecting the work to a post-heat treatment and allowing a reduction of the number of component parts used, suppression of the manufacturing costs, and easiness in the installing operation on a crank shaft. SOLUTION: The torsional damper is composed of a cylindrical boss made of metal furnished with a hole for installation on the crank shaft of an internal combustion engine, a hub part consisting of a rim part formed concentrically at the periphery of the boss part and a mounting part and a mounting part for mounting the rim part on the boss part in which the two are formed in a single piece structure through a sheet metal processing or cold forging, a mass in cylindrical shape arranged concentrically with the rim part, and a cylindrical resilient piece installed between the rim part and the mass fast in a single piece structure, and is structured so that the mounting part is welded to the end face of the boss part, wherein the metal material of the hub part has a carbon equivalent(Ceq) of 0.5% or less while the metal material of the boss part has a carbon equivalent(Ceq) of 0.5% or less and a carbon content of 0.2% or more, and the part contacting with the oil seal part is subjected to induction hardening.</p> |
