US 12,146,573 B2
Shifting mechanisms for split-pulley variable transmissions
Alexander Kernbaum, Sunnyvale, CA (US); Murphy Kitchell, Menlo Park, CA (US); and Thomas Egan, Marblehead, MA (US)
Assigned to SRI International, Menlo Park, CA (US)
Filed by SRI INTERNATIONAL, Menlo Park, CA (US)
Filed on Jul. 5, 2023, as Appl. No. 18/347,294.
Application 18/347,294 is a division of application No. 16/500,024, granted, now 11,732,787, previously published as PCT/US2018/025804, filed on Apr. 3, 2018.
Claims priority of provisional application 62/481,046, filed on Apr. 3, 2017.
Prior Publication US 2023/0341030 A1, Oct. 26, 2023
Int. Cl. F16H 9/20 (2006.01); F16H 55/56 (2006.01)
CPC F16H 9/20 (2013.01) [F16H 55/56 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A transmission having a controllable transmission ratio for more rapid or more controllable shifting, the transmission comprising:
a first conical split pulley having a first half-pulley and a second half-pulley;
a first input member coupled to the first half-pulley and the second half-pulley such that a torque applied to the first input member is transmitted to the first and second half-pulleys;
a second input member;
a screw, wherein the second input member is coupled to the screw such that a differential rotation between the first input member and the second input member causes an axial force to be applied, via the screw, between the first half-pulley and the second half-pulley, thus allowing an axial distance between the first half-pulley and the second half-pulley to increase or decrease, which thereby enables a change in an effective diameter of the first conical split pulley resulting in the controllable transmission ratio of the transmission;
a second conical split pulley having a third half-pulley and a fourth half-pulley, wherein the first conical split pulley is nested within the second conical split pulley; and
a belt that couples the first conical split pulley to the second conical split pulley;
wherein application of a torque via the first input member causes a torque to be transmitted from the first conical split pulley to the second conical split pulley via the belt.