GB1021766A - Method and machine for grinding a toothed wheel - Google Patents

Abstract

1,021,766. Gear-grinding. CARL HURTH MASCHINENUND ZAHNRADFABRIK. Nov. 16, 1962 [March 9, 1962], No. 43390/62. Headings B3B and B3K. [Also in Division F2] In a method of grinding gears, at least one flank of a workpiece tooth is machined during both forward and return strokes of the wheel. The workpiece 25, Figs. 1, 4, 5 and 6 (not shown), is carried on a spindle associated with indexing means 26 and rotating in a sleeve carried by a slide 21. The sleeve carries a replaceable rolling segment 28 engaged by tapes 29a-29d, the tapes being tensioned by levers 44 engaged by adjusting screws 51a, 51b on pistons 54a, in cylinders 55a, 55b, on a slide 31 The slide 31 is mounted on a head 32 which is adjusted vertically by a screw 35. The slide 31 is urged by a spring 58 against a lever 63 positioned by a stop 66 adjusted by a screw 69a and gears 70, 71, the setting being indicated on a dial 72. The wheel 75, Fig. 12 (not shown), is mounted in a head 76 which is angularly and vertically displaceable. The wheel spindle 78 is adjusted in a conical bearing 79 by nuts 83 acting against a thrust race 82 engaged by a spring 81. The spindle is rotated by a motor 84 in a sleeve 80 which can be adjusted axially by a motor or manually through gearing 93, 90 and 89 and a nut 87. In operation, the gear flank 100, Fig. 5, is rolled against the fixed face 107 of the grinding wheel. Due to differences in tape expansion in opposite swings 105, 106 of the segment 28, the tooth 25a does not contact the wheel during one swing, being, say, a distance 110 out of contact. The differences may be compensated by applying an additional tension to the tapes in at least one direction of movement by operating at least one piston 54a through a valve 113, Fig. 4, oscillated in unison with movements of the segment 28. In a modification, only one compensating piston is provided working against an adjustable stop. In a further modification, the need for compensation is avoided by relieving the tapes of tension during the rolling movements. To this end, racks 136, 137, Fig. 7 (not shown), are so urged by electromagnets in time with the oscillations of the spindle-carrying sleeve 23 that, through pinions 126, 127, the force on the tapes is reduced. Alternatively, braking forces may be applied to the sleeve 23 to equalize the tape tension. In another modification, the tapes 29a, 29b, Fig. 10 (not shown), are engaged by cams 142a, 142b moved to positions determined by stops 144, 145 by a rod 147 passing through a friction block 148. In a final modification, the corrections are applied to the grinding wheel 75, Fig. 12 (not shown), which is reciprocated axially by rotating the gears 90 to feed the sleeve 86 through a lever 163 moved by a fluid-controlled piston.