GB1022139A - A method of manufacturing generally cupped and cylindrically shaped parts - Google Patents

Abstract

1,022,139. Making wheels, brake drums, upsetting; corrugating, rolling, stamping. D. S. COX. April 13, 1964, No. 15279/64. Headings B3A, B3E, B3H, B3M and B3Q. A method of making a cupped and cylindrically shaped part such as e.g. a vehicle wheel or brake drum shell cylindrical blank, rolled from strip longitudinally seam welded and if necessary normalized is initially located in a die and expanded over a portion of its length into a conical form by a plurality of radially movable segments 16 actuated by a co-operating wedge 17 and the upper edge of the blank is bent inwardly as at 18. The conical portion is subsequently confined by die members 19, 20 (Fig. 4A, not shown) and the upper portion 15 confined by a movable die member 26 co-operating with a member 22 which, when lowered, arcuately curves the portion 15 inwardly between the die surface 25, 27 and effects an increase in the thickness thereof. The blank is next located in a die, (Fig. 6, not shown) comprising elements 32, 34 having movable segments 35, 37, 45 and the hub section made flat and perpendicular to the blank axis whilst the conical portion is reformed into a cylindrical section 38. Finally the inner annular edge of the blank is trimmed, bolt holes punched and the lip 40 inwardly curled as required to form a brake drum. The lip may be curled and the central portion corrugated by rolling. The upper end of the blank may be rotated on a mandrel and externally tapered by rolls to offset the subsequent unequal thickening which takes place during forming in the dies. To produce a tubeless-type wheel disc a cylindrical blank 2 is initially rotated on a mandrel and the external surface engaged by rollers 64 (Fig. 10A, not shown) which follow cams 68 to vary the wall thickness thereof in predetermined areas related to the contour of the finished wheel and effect lengthening of the blank against a pressure yielding ring 70. Alternatively the varying wall thickness may be made by rolling the strip prior to forming it into the cylindrical blank. The profiled blank is subsequently formed in a similar manner to the brake drum above in successive die units, (Figs. 11, 12 not shown), having radially inwardly and outwardly slidable sets of die segments 121, 122 co-operating with wedge members 126, 127. To produce a locking ring type of wheel the blank is finally formed in a die unit (Fig. 14, not shown) which comprises radially expandable segments 150, a central floating die segment 164 attached to a knockout bar 188 and radially spaced die segments 178 spring biased into their retracted position. As the die closes the segment 164 is pushed against the plate 122, the ring 166 advances to size the blank and the segments are expanded by sliding over the fixed wedge member 152 whilst the segments 178 are advanced by engagement with the cam ring 174 to form a peripheral groove 180 in the rim. Annealing may be carried out between the forming operations and the area of the locking ring groove heated during forming. The blank may be initially upset to reduce its diameter to within 25%-35% of the final diameter of the hub centre hole, annealed and upset to the required size. The dies are so constructed that as they open knock-out members and yieldingly mounted lower die members free the workpiece therefrom.