Patent ID: 6742373
Filing Date: 2004-06-01
Classification: B21D,F16G,Y10T

Abstract:
A method for manufacturing a V-block of a metal belt type continuously variable transmission having an endless metal belt, said endless metal belt comprising a thin metal ring assembly formed by thin metal rings piled on each other stratified and a plurality of V-blocks supported by the thin metal ring assembly along its circumference, each of said V-blocks having a rocking edge defining a boundary between an outer portion thereof of substantially uniform thickness and a tapered inner portion thereof, said endless metal belt being wound round a drive pulley and a driven pulley for controlling speed change ratio by changing widths of grooves of the pulleys, wherein said method comprises:forming each of said V-blocks by punching a V-block press material with a main punch and a counter punch; wherein said V-block press material has a sectional view including an outer portion of about uniform thickness and a tapered inner portion with a slant gently inclined toward an innermost end away from said outer portion of the material from a place distant from a location to become said rocking edge by a predetermined distance inward; wherein said main punch and said counter punch have front shapes of substantially same as that of said V-block; and wherein either punch facing said rocking edge has a slant starting at a place corresponding to said rocking edge and extending inward rising gradually away from said outer portion.