A traction device including a ring member, a carrier, and a sun member and an electric motor, wherein the electric motor is coupled to at least one of the ring member, the carrier, and the sun member.

An infinitely variable multi-epicyclic friction transmission system for an electric motor, the system comprising: a main shaft; a motor drum comprising two cylindrically shaped half-drums disposed axially around the main shaft and separated by a longitudinal gap, the half-drums configured to bear a series of inverted vee-rings splined on an outer circumferential surface of the half-drums so as to be configured to slide longitudinally along the half-drums; a rotor configured to be accommodated in a cavity defined by the half-drums, the rotor comprising a rotor carrier driver configured to be disposed in the longitudinal gap for rotating at least one planetary carrier about the main shaft; a plurality of twin planetary cone assemblies attached to the at least one planetary carrier and disposed circumferentially around the two half-drums, each twin planetary cone assembly comprising: a torque tube and a planetary cone-hemisphere structure provided at each end of the torque tube.

An infinitely variable multi-epicyclic friction transmission system for an electric motor, the system comprising: a main shaft; a motor drum comprising two cylindrically shaped half-drums disposed axially around the main shaft and separated by a longitudinal gap, the half-drums configured to bear a series of inverted vee-rings splined on an outer circumferential surface of the half-drums so as to be configured to slide longitudinally along the half-drums; a rotor configured to be accommodated in a cavity defined by the half-drums, the rotor comprising a rotor carrier driver configured to be disposed in the longitudinal gap for rotating at least one planetary carrier about the main shaft; a plurality of twin planetary cone assemblies attached to the at least one planetary carrier and disposed circumferentially around the two half-drums, each twin planetary cone assembly comprising: a torque tube and a planetary cone-hemisphere structure provided at each end of the torque tube.

A multi-stage planetary roller power transmission device includes a high-speed power transmission mechanism including a first sun shaft, a first fixed ring, first planetary rollers disposed between the first sun shaft and the first fixed ring with a first negative clearance, first support shafts, and an annular first carrier into which the first support shafts are press-fitted; and a low-speed power transmission mechanism including a second sun shaft, a second fixed ring, second planetary rollers disposed between the second sun shaft and the second fixed ring with a second negative clearance, second support shafts, and an annular second carrier into which the second support shafts are press-fitted. A clearance amount of the first negative clearance and a clearance amount of the second negative clearance are equal to each other, and the number of the first planetary rollers is smaller than the number of the second planetary rollers.

An infinitely variable multi-epicyclic friction transmission system for an electric motor, the system comprising: a main shaft; a motor drum comprising two cylindrically shaped half-drums disposed axially around the main shaft and separated by a longitudinal gap, the half-drums configured to bear a series of inverted vee-rings splined on an outer circumferential surface of the half-drums so as to be configured to slide longitudinally along the half-drums; a rotor configured to be accommodated in a cavity defined by the half-drums, the rotor comprising a rotor carrier driver configured to be disposed in the longitudinal gap for rotating at least one planetary carrier about the main shaft; a plurality of twin planetary cone assemblies attached to the at least one planetary carrier and disposed circumferentially around the two half-drums, each twin planetary cone assembly comprising: a torque tube and a planetary cone-hemisphere structure provided at each end of the torque tube.

An infinitely variable multi-epicyclic friction transmission system for an electric motor, the system comprising: a main shaft; a motor drum comprising two cylindrically shaped half-drums disposed axially around the main shaft and separated by a longitudinal gap, the half-drums configured to bear a series of inverted vee-rings splined on an outer circumferential surface of the half-drums so as to be configured to slide longitudinally along the half-drums; a rotor configured to be accommodated in a cavity defined by the half-drums, the rotor comprising a rotor carrier driver configured to be disposed in the longitudinal gap for rotating at least one planetary carrier about the main shaft; a plurality of twin planetary cone assemblies attached to the at least one planetary carrier and disposed circumferentially around the two half-drums, each twin planetary cone assembly comprising: a torque tube and a planetary cone-hemisphere structure provided at each end of the torque tube.

A planetary variator applicable in a variable transmission for realizing a variable speed and torque ratio includes: a ring wheel; at least two planet wheels, the at least two planet wheels including a shaft portion and a wheel portion that is rotatable about the shaft portion, the shaft portion having a longitudinal central axis, the longitudinal central axis also being the rotation axis of the wheel portion, each planet wheel being freely rotatable about a hinge axis that is oriented essentially perpendicularly with respect to a plane defined by the common central axis and the rotation axis of the wheel portion of the planet wheel; and a sun wheel. The ring wheel and the sun wheel are axisymmetric bodies positioned with respect to a common central symmetry axis. Interaction between the ring wheel, the at least two planet wheels, and the sun wheel takes place through a rolling motion.

A planetary variator applicable in a variable transmission for realizing a variable speed and torque ratio includes: a ring wheel; at least two planet wheels, the at least two planet wheels including a shaft portion and a wheel portion that is rotatable about the shaft portion, the shaft portion having a longitudinal central axis, the longitudinal central axis also being the rotation axis of the wheel portion, each planet wheel being freely rotatable about a hinge axis that is oriented essentially perpendicularly with respect to a plane defined by the common central axis and the rotation axis of the wheel portion of the planet wheel; and a sun wheel. The ring wheel and the sun wheel are axisymmetric bodies positioned with respect to a common central symmetry axis. Interaction between the ring wheel, the at least two planet wheels, and the sun wheel takes place through a rolling motion.

A continuously-variable planetary transmission including: (a) first and second spaced rotatable transmission elements spaced around a transmission axis and having first and second contact points, respectively; (b) at least one support element in fixed radial position with respect to the transmission axis and each having a third contact point; and (c) at least one elongate, rotationally-symmetric, rotatable planetary rolling element, each rolling element (1) contacting the transmission elements at the first and second contact points and each support element at its third contact point, the contact points each in frictional rolling connection to the at least one rolling element and (2) being supported by the first and second transmission elements and the at least one support element with freedom to move around the transmission axis; and (d) an adjusting device for displacing the center of each planetary rolling element to change the ratio of the transmission.

A continuously-variable planetary transmission including: (a) first and second spaced rotatable transmission elements spaced around a transmission axis and having first and second contact points, respectively; (b) at least one support element in fixed radial position with respect to the transmission axis and each having a third contact point; and (c) at least one elongate, rotationally-symmetric, rotatable planetary rolling element, each rolling element (1) contacting the transmission elements at the first and second contact points and each support element at its third contact point, the contact points each in frictional rolling connection to the at least one rolling element and (2) being supported by the first and second transmission elements and the at least one support element with freedom to move around the transmission axis; and (d) an adjusting device for displacing the center of each planetary rolling element to change the ratio of the transmission.