Patent GB-539538-A (GB)
Title: Improvements relating to friction gearing
IPC: F16H61/662
Filed: 1939-09-14
Abstract: 539,538. Variable-speed gearing. NAAMLOOZE VENNOOTSCHAP CONVERTO. Sept. 14, 1939, No. 25851. Convention date, Sept. 15, 1938. [Class 80 (ii)] In gearing of the kind comprising balls or other rolling members which co-operate with surfaces provided on driving and reaction members and co-axial with the driving and driven members, and co-operate also with surfaces provided on the driven members and not co-axial with the driving and driven members, camming or wedging surfaces separate from the above-mentioned surfaces are provided for effecting longitudinal displacement of the reaction member to vary the speed ratio. The camming surfaces may consist of a screw and nut, or helicoidal races with interposed balls. In the mechanism shown in Fig. 1, planetary balls 134 co-operate with co-axial races on a member 137 secured to the driving-shaft 145, and a reaction-member 135 provided with a brake 136 respectively, and co-operate also with cups 138 mounted on inclined axis a ... a on a carrier 144. The shafts 141 of the cups are mounted on ball-bearings 140 in resilient parts 142 of the carrier. A disc 135a on the reaction-member is mounted on roller-bearings 160 on a sleeve 162 engaging centrifugal masses 163 which are fulcrumed on a sleeve 165 on the driven shaft 153 and engage rubber blocks 164. The carrier 144 and bearings 160 are separated by rings 156, 157 formed with staggered, inclined races co-operating with three balls 158 to effect relative axial movement of the reaction-member 135 and ball-cups 138 during speed-change. The balls 158 co-operate also with a separator consisting of a loose ring 159 provided, preferably in copper strips, with ballcavities. The tangent-surface between each ball 134 and cup 135 passes through the point of intersection of the axes y-y and a-a of the ball and cup, the arrangement enabling them to roll on each other without slip or spinning friction, regardless of their relative position. The balls 158 and co-operating races can be replaced by elliptic or like members which co-operate in the manner of toggles with grooves in the rings 156, 157. To compensate for centrifugal force, the balls 134 engage recesses 179a, Fig. 8, in members 179 which are mounted' on springs 179b on a spider 154 secured to the carrier 144, and abut on fingers 178 thereon. When the motor is braked, the shaft 153 drives, and the members 179 are swung over and slip from one side to the other of the fingers 178. The members 179 and fingers 178 may be replaced by rollers which are mounted on the resilient parts 142 of the carrier 144 and abut on the balls. The rollers may be employed for transmitting torque from the secondary shaft, in which case the centrifugal masses 163 may be omitted. In the mechanism shown in Fig. 10, planetary balls 200 co-operate with races 201, 203, and cones 206 mounted on inclined axes on a resilient carrier 219. The race 203 is mounted in a housing 204, provided with a brake. The race 201 is formed on a ring 202 having a toroidal surface 208 co-operating with three balls 209 which engage helical grooves 210 in a member 211 splined to the driving-shaft 250. The balls 209 are mounted in a cage 212 in connection with a torsion spring 214 which urges the balls 209 into such a position that the points of contact of the balls 200 and race 201 are approximately in the axes of rotation of the rollers. Balls 220 and inclined races 221, 222 are arranged between the carrier 219 and the driven shaft 215. When the shaft 250 drives, the balls 209, 220 effect adjustment of the carrier 219, race 201 and the balls 200. Normally, a spring plate 216 holds the housing 204 in such a position that the balls 200 do not press on the race 203, and the engine can run idly. The cups 138, Fig. 1, or cones 206, Fig. 10, may be replaced by a ring mounted on ball-bearings in a non-rotatable cup. The planetary balls may be replaced by non-spherical members running on ball-bearings on the carrier. Specification 352,778 is referred to.