GB1470224A - Infinitely variable gear with a mechanical contact pressure regulator - Google Patents

Abstract

1470224 Variable-ratio friction gear NEUWEG FERTIGUNG GmbH 19 June 1974 [19 June 1973] 27232/74 Heading F2D In an infinitely variable ball friction gear in which planetary balls 32 spaced by a cage 34 are engaged by a bearing ring 28 driven by the input shaft 20, bearing ring 46 driving the output shaft 22, and guide rings 30, 50 of which the latter is axially adjustable to determine the transmission ratio, a contact pressure regulator comprises balls 38 reacting between the ring 30 and a thrust ring 36 either of which is formed with ramps 60, Fig. 2, of which the angle of slope, gamma, increases, starting from the point on a ramp at which a ball 38 makes contact at the lowest transmission ratio n 2 /n 1 , where n 1 and n 2 are the input and output speeds respectively, according to the equation gamma (radians) = (1 + 15#(n 2 /n 1 )F/R, where F is the distance between the centres of the balls 32 and the principal axis 24 of the gear, and R is the mean radius of the ramps. The ramps terminate at their highest points, corresponding to the positions of the balls 38 at the highest ratio n 2 /n 1 , in portions 62 of greater slope than that given by the above equation. Ramps 60<SP>1</SP>, 62<SP>1</SP> extend in the opposite direction so that the gear operates in either sense of rotation. The ring 50 has ramps 52 coacting with fixed rollers 54 so that it is adjusted axially to vary the transmission ratio when turned by a worm gear 58, 56. The bearing ring 28 and the thrust ring 36 are secured to a sleeve 26 which is axially slidable but non-rotatable relatively to the input shaft 20, and the cage 34 and ring 30 are rotatable on the sleeve 26, the ring 30 being axially loaded by a spring 42.