ES293236A1 - Wheel manufacture - Google Patents

Abstract

A method of making a wheel having a disc 12, Figs. 1-23 (not shown), and at least a part 18 of the rim formed as a seamless unitary structure from a sheet-metal disc-shaped blank 30, comprises subjecting the blank to at least one pressing operation to shape the outer peripheral portion of the blank to form the part 18. The apertured blank 30 (Fig. 2) is cupped in a twostage operation between dies 32-34 (Fig. 3), the flange of the blank then being hot-shaped between a roll 37 (Fig. 4) and an expansible supporting roll 35 on which the blank is held by a disc 36. A hot-pressing operation follows (Fig. 5) to steepen the outer wall 21 of a circumferentially extending gutter-groove 20 to be formed in the rim. This is followed by flaring of the rim between dies 38, 40 (Fig. 6), and then by a final hot-shaping operation between an expansible carrier roll 41 (Fig. 7), and a roll 42. Alternatively, the last rolling operation may be replaced by mounting the cupped blank on an expansible roll 43 (Fig. 8) movable horizontally to carry the blank against forming rolls 44, 45 coupled by a chain and driven by an electromotor. Instead, the gutter groove 20 may be formed by an outer roll 49 (Fig. 9) and an inner roll 48 of smaller radius A-A than that B-B of the blank. In a modification, the only rolling operation thins the flat blank towards its circumference (Fig. 10). This is followed by a cold cupping operation (Fig. 11), and a pressing operation (Fig. 12) to reduce the free edge of the rim. Hot pressing follows, forming the undercut edge of the groove (Fig. 13), then a final hot pressing with a divided die 62 (Fig. 14) which forms a rebate 64 for lapping on a similar rebate of the other sector 22 (Fig. 1) of the rim, the sections being joined by welding 24 at the lap joint. The other section 22 is produced from a cylindrical blank 70 (Fig. 15) of thickness equal to the maximum thickness of the finished section and reduced at the edges by rolls 71, 72. Two pressing stages follow (Figs. 16 and 17), after which edge 81 of the blank is rebated. If the section 22 is made from a blank of thickness equal to the thinnest section of the finished section, the thickness of the blank is increased locally by hot pressing (Fig. 18). Alternatively, a pressing operation (similar to that in Fig. 16) may be followed by further pressing operations turning out the free edge of the rim (Figs. 19 and 20), the final form being produced by rolling and/or pressing operations. In a further form (Fig. 23) the whole rim is formed in one piece integrally with the wheel disc, and the wheel is formed in several pressing operations and a flow-turning operation.