Patent GB-926008-A (GB)
Title: Improvements in infinitely variable planetary friction transmission
IPC: F16H15/54
Filed: 1961-01-06
Abstract: 926,008. Variable speed epicyclic gear. K. MAICHEN. Jan. 6, 1961 [Jan. 11, 1960; July 22, 1960], No. 644/61. Class 80 (2). In a variable speed epicyclic friction gear for motor vehicles or machine tools, wherein planetary friction cones 12, mounted on an input carrier 7 and having their axes inclined to, and their outer generatrices parallel to, the carrier axis, centrifugally engage a stationary annulus 14 axially moved to vary the velocity ratio, the cones 12 have releasably connected thereto friction or toothed cones 13 engaging an output annulus or sun 15, and are mounted on transversely slidable spindles 10 borne by blocks 9 connected to the carrier by inclined dovetail guides 8. In Fig. 1, the engaging surface of the annulus 14 may be cylindrical, part-toroidal as shown, or of plastic and of cardioid cross-section so as to flatten under load (Fig. 2, not shown). The annulus 14 may be formed as a piston and axially moved hydraulically, or, as shown, may be manually shifted by a lever 16. Friction cones 13, connected to the cones 12 by teeth 20, and the preferably plastic sun 15, connected to a hollow output shaft 5, may be replaced to change the ratio range. The carrier 7 is secured to a driving shaft 3 which extends through a casing 1 and may be connected to a driving element at either or both ends. Spring washers 18. assist the centrifugal engagement of the cones 12. Reactive thrust provided by a helical gear 6 on the output shaft 5, is also used to press the cones 12, 13 against their associated rolling surfaces. In motor vehicles the sun 15 may be flexibly coupled to the output shaft 5. In Fig. 3 (not shown) the cones 12, 13 are connected by friction or toothed planetary gearing comprising stepped planets carried by the cones 12 respectively meshing suns fixed to the spindle 10 and suns keyed to the cones 13. The cones 13 and the sun 15 are connected by gear teeth having pitch cone running shrouds. In Fig. 5, friction cones 13 secured to the cones 12 are engaged by an annulus 15 ported for assembly of the cones 13 and by a freely rotating bearing wheel 74. The annulus 15 is connected to output through teeth 80, a sleeve 81, axial camming means comprising balls 83 in V-grooves 82, and a sleeve 85. Reactive axial thrust from the balls 83, acting through a ball-bearing 87, spring washers 18 and a sleeve 77, is transmitted to the blocks 9 through an element 78 to increase engagement pressure between the cones 12 and the annulus 14, and to the bearing wheel 74, through nuts 91 and ball-bearing 92, to increase engagement pressure between the cones 13 and the annulus 15. As shown, in motor vehicles, the sleeve 85 is connected to the output shaft 5 through centrifugal clutch means comprising conical masses 44 acting on, and pivoted at 51 in, axially movable clutch elements 39, 41 which are connected together by a helical tension spring and to the output shaft 5 through teeth 45, 46, and respectively have clutch teeth 38, 48 for respective engagement with an element 96 connected to the sleeve 85 through teeth 95 and element 49 secured by a pin 50 to the driving shaft 3. Synchronizing friction discs or, as shown, cones are provided between the axially movable clutch elements 39, 41 and the elements 96, 49, respectively. In the outer position of the masses 44 the clutch teeth 38, 48 are respectively disengaged and engaged for direct drive, whereas in the inner, low-speed position of the masses the clutch teeth 38, 48 are respectively engaged and disengaged for drive through the cones 12, 13. In machine tools, drive is direct from the sleeve 85 to the output shaft 5, and the annulus 14 is manually adjusted through a rack and pinion.