Process for producing a pulley for a continuously variable belt drive transmission

A process for producing a pulley for a continuously variable belt drive transmission including an input pulley, an output pulley and an endless belt disposed between the input and output pulleys, the input and output pulleys having tapered surfaces contacted with the endless belt, respectively, the endless belt including a plurality of metal elements stacked on each other in a thickness direction thereof, the metal elements each having a plurality of microscopic projections and recesses on opposed side faces which are contacted with the tapered surfaces of the input and output pulleys, the tapered surfaces of at least one of the input and output pulleys being formed with microgrooves in the form of concentric grooves or a continuous helical groove, in which a relationship represented by the following expression:

• W1≧(W2+W3), wherein W1 is a width of each of the microscopic projections on the side faces of the metal elements, W2 is a width of a top surface of each of microprojections defined between the adjacent microgrooves, and W3 is a width of each of the microgrooves, is satisfied, the process comprising:
• subjecting tapered surfaces of a preform of at least one of the input pulley and the output pulley to surface hardening;
• subjecting the surface-hardened tapered surfaces of the preform to hard turning to form the microgrooves radially spaced from one another thereon, between which microprojections are formed;
• and
• reducing a height of the microprojections to thereby provide the at least one of the input pulley and the output pulley having the tapered surfaces with the microgrooves which satisfy said relationship.