Method of manufacturing pulley cover in continuously variable transmission

A method of manufacturing a pulley cover in a continuously variable transmission in which an endless transmission member is wound around a drive pulley and a driven pulley and which shifts a gear ratio by changing a groove width of the drive pulley and a groove width of the driven pulley by means of hydraulic pressure, at least one of the drive pulley and the driven pulley including a fixed pulley half fixed on a rotary shaft, a movable pulley half supported on the rotary shaft in such a way as to be incapable of rotation relative thereto but capable of movement in an axial direction, a pulley cover fixed to the rotary shaft and facing a rear surface of the movable pulley half, and first and second hydraulic oil chambers defined inside the pulley cover and separated in an inner side and an outer side in a radial direction by an annular partition wall, the movable pulley half being configured to be biased toward the fixed pulley half by hydraulic pressure supplied to the first and second hydraulic oil chambers,

• the method comprising:
• manufacturing the pulley cover by machining a metal sheet, the machining of the metal sheet comprising:
• press-forming the annular partition wall;
• opening an oil hole in the partition wall, the oil hole allowing communication between the first and second hydraulic oil chambers;
• and
• then press-forming a peripheral wall of the second hydraulic oil chamber at an outer side, in the radial direction, of the partition wall so as to make the peripheral wall of the second hydraulic oil chamber extend substantially parallel to and be opposed to said annular partition wall.