Continuously variable transmission
View Patent ↗Traction planets and traction rings can be operationally coupled to a planetary gearset to provide a continuously variable transmission (CVT). The CVT can be used in a bicycle. In one embodiment, the CVT is mounted on the frame of the bicycle at a location forward of the rear wheel hub of the bicycle. In one embodiment, the CVT is mounted on and supported by members of the bicycle frame such that the CVT is coaxial with the crankshaft of the bicycle. The crankshaft is configured to drive elements of the planetary gearset, which are configured to operationally drive the traction rings and the traction planets. Inventive component and subassemblies for such a CVT are disclosed. A shifting mechanism includes a plurality of pivot arms arranged to pivot about the centers of the traction planets as a shift pin hub moves axially.
1. A bicycle comprising:
a plurality of bicycle frame members configured to form a support structure;
a crankshaft operationally coupled to one or more cranks of the bicycle, the crankshaft configured to be supported with the plurality of bicycle frame members; and
a continuously variable transmission (CVT) coaxially coupled with, and coaxially mounted about, the crankshaft, the CVT comprising:
a plurality of spherical traction planets;
a pivot arm coupled to each traction planet;
a traction sun coupled to each traction planet, the traction sun located radially inward of the traction planets;
an input ring in contact with each of the spherical traction planets, the input ring located radially outward of the traction sun;
an output ring in contact with each of the spherical traction planets, the output ring located radially outward of the traction sun, wherein each spherical traction planet is placed between the input ring and the output ring; and
a cage coupled to each of the spherical traction planets, the cage located in between the input and output rings and is operationally connected to a hub shell by splines.
2. The bicycle of claim 1 , wherein a housing of the CVT is incorporated with the bicycle frame members.
3. The bicycle of claim 1 , wherein a housing of the CVT incorporates a carrier of a planetary gear set.
4. The bicycle of claim 1 , further comprising a planetary gear set.
5. The bicycle of claim 4 , wherein the carrier of the planetary gear set is incorporated with the housing of the CVT.
6. The bicycle of claim 4 , wherein the crankshaft is configured to drive a ring gear of the planetary gear set.
7. The bicycle of claim 6 , wherein the ring gear is configured to drive planetary gears of the planetary gear set.
8. The bicycle of claim 7 , wherein the planetary gears are configured to drive a sun gear of the planetary gear set.
9. The bicycle of claim 8 , wherein the sun gear is configured to drive an input driver of the CVT.
10. The bicycle of claim 9 , wherein the input driver is operably coupled to a traction ring of the CVT.
11. The bicycle of claim 1 , further comprising a pivot pin hub coupled to the pivot arms.
12. The bicycle of claim 11 , wherein an axial movement of the pivot pin hub causes a pivoting of the pivot arms.
13. The bicycle of claim 1 , further comprising an axle coupled to each of the spherical traction planets, wherein the axle couples to the pivot arm.