Electric traction drives
View Patent ↗Inventive embodiments are directed to components, subassemblies, systems, and/or methods for electric traction drives employing a continuously variable transmission (CVT) having a variator provided with a plurality of tilting traction planets and opposing traction rings. In one embodiment, an electric traction drive is provided with an electromotive device configured to transfer power to or from a traction sun of a CVT. In other embodiments, an electric traction drive is provided with an electromotive device that couples to certain components of a CVT such as a traction ring, a carrier assembly, and a main axle. Various inventive shifting assemblies having shift cams and shift cam cages can be used to facilitate adjusting the transmission speed ratio of a CVT. Various related devices include embodiments of, for example, a power input apparatus, a speed ratio shifter, a shift cam actuator, a shift nut, and a carrier assembly configured to support the tilting traction planets.
1. An electric traction drive having a continuously variable transmission, comprising:
a plurality of traction planets distributed radially about a longitudinal axis, each traction planet configured to rotate about a planet axle, the planet axle providing a tiltable axis of rotation, wherein an adjustment of a tilt position of the planet axle adjusts a speed ratio of the continuously variable transmission;
a first traction ring in contact with the plurality of traction planets;
a rotatable traction sun coaxial about the longitudinal axis and positioned radially inward of and in contact with each of the traction planets, the traction sun coupled to a traction sun shaft;
a second traction ring in contact with the plurality of traction planets; and
an electromotive device operably coupled to the second traction ring, the electromotive device comprising:
an electric motor winding coupled to the traction sun shaft; and
an electric rotor, wherein the electric motor winding and the electric rotor are configured to rotate in opposite directions on axes coincident with the longitudinal axis.
2. The electric traction drive of claim 1 , further comprising an array of magnets operably coupled to the second traction ring.
3. The electric traction drive of claim 2 , wherein the array of magnets is coupled to the second traction ring via a frame.
4. The electric traction drive of claim 1 , further comprising a load cam assembly coupled to the electric rotor.
5. The electric traction drive of claim 3 , wherein the frame is coupled to a thrust support structure configured to provide thrust to an axial force thrust bearing.
6. The electric traction drive of claim 1 , further comprising a wiring harness communicatively coupled to a controller and further configured to transmit electrical power into the electromotive device.
7. A vehicle, comprising:
a power source; and
an electric traction drive having a continuously variable transmission, comprising
a plurality of traction planets distributed radially about a longitudinal axis, each traction planet configured to rotate about a planet axle, the planet axle providing a tiltable axis of rotation, wherein an adjustment of a tilt position of the planet axle adjusts a speed ratio of the continuously variable transmission,
a first traction ring in contact with the plurality of traction planets,
a rotatable traction sun coaxial about the longitudinal axis and positioned radially inward of and in contact with each of the traction planets, the traction sun coupled to a traction sun shaft,
a second traction ring in contact with the plurality of traction planets, and
an electromotive device operably coupled to the second traction ring, the electromotive device comprising
an electric motor winding coupled to the traction sun shaft, and
an electric rotor, wherein the electric motor winding and the electric rotor are configured to rotate in opposite directions on axes coincident with the longitudinal axis.
8. The vehicle of claim 7 , further comprising an array of magnets coupled to a frame for rotation about the longitudinal axis, the frame being coupled to a load cam assembly configured to drive the second traction ring.
9. The vehicle of claim 8 , wherein the frame is coupled to a thrust support structure configured to provide thrust to an axial force thrust bearing.
10. The vehicle of claim 7 , further comprising a load cam assembly coupled to the electric rotor.
11. The vehicle of claim 7 , further comprising a wiring harness communicatively coupled to a controller and further configured to transmit electrical power into the electromotive device.