Patent ID: 8815020
Filing Date: 2014-08-26
Classification: B21D,C21D,C23C,F16G

Abstract:
1. A method of manufacturing a laminar ring which is used for a power transmitting belt of a belt-type continuously variable transmission for a vehicle and which is constituted by a plurality of annular endless metallic band members having respective different circumferential lengths and tightly laminated on each other to support a plurality of circularly arranged elements of the power transmitting belt, comprising: a nitriding treatment step of subjecting surfaces of said plurality of metallic band members to a nitriding treatment wherein the metallic band members are kept in a controlled predetermined atmosphere for a predetermined length of time while gaps are formed between circumferential portions of adjacent ones of the metallic band members laminated on each other such that a position of said gaps is moved relative to the metallic band members in a circumferential direction of the metallic band members.