GB1153572A - Variable Ratio Transmission Unit - Google Patents

Abstract

1,153,572. Variable-speed friction-gearing. NATIONAL RESEARCH DEVELOPMENT CORP. 15 July, 1966 [16 July, 1965], No. 30321/65. Heading F2D. In a steplessly variable-speed friction-gear in which coaxial rollers 8, 9 secured respectively to aligned driving and driven shafts 6, 7 engage idler-discs 21, 22 on a carrier 14, axially adjustable by a screw to vary the ratio, the discs 21, 22 are supported by spherical bearing seatings on bushes 20, 19 initially pre-loaded against the discs by a central screwed rod 27 and further loaded against the discs by the torque transmitted which causes the carrier 14 to turn relatively to the fixed input and output shaft mountings 4, 5 to actuate means to press the discs 21, 22 upon the rollers 8, 9 with a force varying in proportion to the torque transmitted. As shown, the means comprises a yoke 33, sandwiched between the bush 19 and nut and washer 28, 32, having a rod 34 freely turnably mounted in a lug 35 of the carrier 14 and welded at its outer end to one end of an arm 36 which is supported at its other end by a pin-and-slot connection 42, 43 in the ratio adjusting screwed sleeve 38, 39, turning movement of the carrier due to torque reaction serving to pivot the arm 36 to turn the rod 34, whereby the yoke 33 is canted to increase end loading of the discs 21, 22. Alternatively, turning movement of the carrier may be restrained hydraulically, fluid being expelled from one fluid chamber into another fluid chamber inserted between the washer 27 and bush 17, the chambers being arranged to provide the necessary force multiplication for adequate loading of the discs 21, 22 against the rollers 8, 9. The rollers 8, 9 may have driving surfaces 10, 11 of rounded crosssection in the form of toroidal rings nesting in grooves in the rollers.