Patent GB-996933-A (GB)
Title: Improvements in and relating to infinitely variable conical disk transmissions
IPC: F16H9/12
Filed: 1963-11-14
Abstract: 996,933. Expanding wheel gear; variablespeed friction gear; ratchet clutches. W. REIMERS. Nov. 14, 1963 [Nov. 15, 1962], No. 44944/63. Headings F2C and F2D. Relates to a continuously variable speed gear, for motor vehicles or machine tools, having conical drive members axially slidable on the transmission shafts for ratio variation, wherein cam means providing traction pressure loading dependent on torque and gear ratio comprises inversely inclined varying-pitch helical camtracks and co-operating rolling elements arranged between at least one of the shafts and an axially slidable conical drive member thereon. To obviate lost-motion and resulting harmful knocking on torque reversal due to cam-track changeover of the rolling elements in such a gear, the cam means comprises inversely inclined, outer and inner sets of helical camtracks and rolling elements of which sets the outer and inner cam-tracks (Figs. 1 and 2) or rolling elements (Figs. 4, 6) are relatively rotatable on ratio-change axial sliding of the conical drive member so that both the outer and inner cam-tracks are held in constant engagement with their co-operating rolling elements. The gear may comprise friction V- belts or chains (Figs. 1 and 2) or tooth-forming chains between expanding conical pulleys (with simultaneous operation of driving and driven pulleys) or cones arranged on intersecting axes and in frictional contact with each other (Figs. 4, 6). In Fig. 1, an expanding conical pulley comprises pulley halves 2, 3 jaw-coupled together at 6, freely rotatable but respectively axially fixed and slidable on a shaft 1, and engaging a double roller chain 4. Rollers 10, 11 carried by radial shafts 9 on a disc 8 fixed to the shaft 1 engage inversely inclined varying-pitch helical cam-tracks 13, 16 respectively on an outer sleeve 12 integral with the slidable pulley half 3 and on an inner sleeve 15 acting on the half 3 through a thrust bearing 17. The sleeves 12, 15 have inversely inclined, varying-pitch helical slots 18, 19 intersecting to form openings 20 each accommodating a pair of rollers 21, 22 carried by a radial shaft 23 and respectively movable in the slots 18, 19. The shafts 23 are mounted in an axially adjustable ring 24'engaging, through a bearing 25, a non-rotatable axially adjustable ratio-setting ring 26. When the ring 26 is axially moved the rollers 21, 22 are also axially moved and effect relative rotation of the sleeves 12, 15 so that the pulley half 3 is axially moved for such a distance that the two cam-tracks 13, 16 remain in engagement with their co-operating rollers 10, 11. In Fig. 2, the pulley half 3 is directly axially moved by a ratio-setting ring 30 acting through a thrust bearing 32. Outer and inner sleeves 33, 34 thrusting on the pulley half 3 and comprising inversely inclined varying-pitch helical camtracks 35, 35<SP>1</SP> engaging the axially fixed outer and inner rollers 10, 11 alternately drivingly engage the pulley half 3 through a double friction roller ratchet clutch 36 comprising rollers 40, 41 engaging cylindrical surfaces 38, 39 of the sleeves 33, 34 and a common polyhedral hub of the pulley half 3. The rollers 40, 41 are held staggered in a common cage 42 so that engagement of one set of rollers releases the other set. In one direction torque is transmitted through the rollers 11, cam-tracks 35<SP>1</SP>, the sleeves 34, and the rollers 41, whereas in the other direction torque is transmitted through the rollers 10, cam-tracks 35, the sleeves 33 and the rollers 40. In order that the unloaded freely rotatable cam-tracks will follow the loaded cam-tracks, auxiliary rollers 47, 48 mounted on the disc 8 engage auxiliary cam-tracks backing on the cam-tracks 35, 35<SP>1</SP>. In Figs. 4, 6 two friction cones 52, 54 are respectively loose and axially slidable on shafts 51, 53 arranged at right angles. The cone 54 is axially moved, to vary the gear ratio, by a hand wheel acting through a screw and nut 56, 58 and a bell-crank lever 60. Outer and inner rollers 69, 70 on relatively rotatable sleeves 65, 66 engage outer and inner cam-tracks on a disc 62 fixed on the shaft 51. The sleeves 65, 66, thrusting on the cone 52, alternately drivingly engage the cone 52 through a double friction roller ratchet clutch 78 comprising rollers 79, 80 carried in a common U -sectioned cage 81 and engaging cylindrical surfaces on the sleeves 65, 66 and a common ratchet flange 75 of the cone 52. In order that the unloaded freely rotatable sleeve will follow the loaded sleeve a spiral spring 82 under torsion tends to turn one sleeve relative to the other.