GB1125713A - An improvement in the generating method of cuttinggears and apparatus therefor - Google Patents

Abstract

1,125,713. Gear-cutting. YUTAKA SEIMI. TSU KOGYO. 24 Nov., 1965 [27 Nov., 1964; 30 Sept., 1965 (2); 5 Oct., 1965 (2)], No. 49848/65. Heading B3K. A gear-cutting or -grinding machine for generating bevel and hypoid gears comprises a spindle carrying the workpiece 3 and a master gear 4 on an oscillatory table 1, and an arcuate gear 6 engaging the master gear 4 to cause rocking of the work about its axis and about the table axis, the arcuate gear being displaceable along its pitch circle to determine the spiral angle of each tooth surface to be cut. When the table 1 is oscillated, rack-andpinion gearing 7, 9, 9<SP>1</SP>, 11 rotates a cam 12 to determine the modifying effect of the movement of the arcuate gear 6 in its guide 13. By disengaging a clutch C, the cam is rendered inoperative. Thus, the work may be rotated through a small angle by a cam 16, Fig. 4(a), contacting the follower 6<SP>1</SP>,Fig. 1, to control the tooth space width, the cam adding an increment of motion to the arcuate gear at one end of a generating swing but maintaining the new position during the return stroke. Or a cam 17, Fig. 5(a), may be used which modifies the spiral angle on a return stroke, or a further cam may modify the spiral angle during the initial stroke. Alternatively, the cam may have two non-circular portions. In all of these embodiments, the shaft 18, Fig. 1, is driven through a double-acting ratchet device 11a,11b, Fig. 7, so that the cam rotates unidirectionally. The work is indexed by rolling the gear 4, at each end of its movement, on to a gear portion 25 or 26, Fig. 8, and moving the portion relatively to the arcuate gear. The table 1 is oscillated by a reciprocating, fluid-pressure device 36, Fig. 11, carrying a roller 38 engaging a groove in the table. In a modification, the shaft 2 is oscillated by a D.C. motor or worm gearing.