GB464764A - Improvements in or relating to friction transmission mechanisms - Google Patents

Abstract

464,764. Friction gearing. ERBAN, R. Sept. 23, 1935, No. 26354. [Classes 80 (i) and 80 (ii)] A friction roller 115, Fig. 7, which works between oppositely-running races, not shown, is free to swing about an axis AA oblique to the plane of the roller. The axis cuts tangentplanes of the contacts of the roller with the races at points one on each race which lie each on the approach side of a plane containing the contact point and the roller axis. The object is to get stability of the roller, and the invention is a development of the arrangement described in Specification 283,934, [Class 80 (ii)], in which the axis of free swing is oblique to the race but not to the plane of the roller. Analytical diagrams are furnished. In the precessional variable-speed gear with toric discs shown in Fig. 1, 2 and 3, this oblique axis AA passes through the centre of the roller 15, which it does not do in the arrangement of Fig. 7. A ball 33 which supports each roller at its centre is supported on a lug 17 of a spider 16 through which spider passes loosely a shaft 12 carrying a toric race disc 11. The other race disc is loose and shown at 10, and the usual adhesion pressure generating device is not shown. Swivel mounted on each ball 33 is a bearing element 35 upon which the roller 15 rotates between shoulders 36. The inner shoulder 36 has a pin extension 41 which passes freely through a ball 14 which is pressed into an arcuate groove 45 upon the spider 16 by a cup 25 upon a control arm 24. There is an arm 24 for each roller 15, and these arms are rigid with a control hub 23 which is rocked about the shaft 12 by moving a ball end 30 to bring the axis AA to other positions such as A<1>A<1> and A2A2 where precession starts and continues until a change in the speed ratio has been completed. In a form shown in Figs. 4 and 6, the roller 215 is in a carrier 212 which rocks about trunnions 240. The obliquity of the axis DD about which the roller 215 is free to rock is obtained by an oblique cylindrical bearing surface between inner and outer bushes 222, 224 fast respectively to a through pivot pin 220 and to a bearing 216 on which the roller turns freely. When the direction of the power transmission reverses, the obliquity of the axis DD must be reversed, and this is provided for by allowing the pin 220 to turn freely through a limited angle with respect to the carrier by lost-motion means 221, 245.