Provided is a friction transmission device including an input raceway ring, a planetary rolling element that is disposed around a rotation axis of the input raceway ring and comes into contact with the input raceway ring; an output raceway ring that comes into contact with the planetary rolling element and is connected to an output shaft, and a first support raceway ring and a second support raceway ring that come into contact with the planetary rolling element. A quadrangle is formed by extension lines of normal vectors at contact points between the planetary rolling element and the respective raceway rings.

A multistage friction/traction speed adapter having a first drive which can include a plurality of free rollers orbiting around a sun element within a frame, transmitting their orbiting movement to guided rollers which do not contact the sun element or the frame. The guided rollers are driven in the orbiting movement and transmit the rotary movement to a carrier via corresponding pins which engage with the carrier. A second drive can include rollers having radial position variation which is prevented from being transmitted to the carrier by providing accommodation at the pin level, either by providing a bushing around the pins with a bore that is eccentric relative to its outer surface, either by engaging the pins into the carriers in portions thereof which are made more flexible. A friction/traction gear at an angle is also disclosed.

A multistage friction/traction speed adapter having a first drive which can include a plurality of free rollers orbiting around a sun element within a frame, transmitting their orbiting movement to guided rollers which do not contact the sun element or the frame. The guided rollers are driven in the orbiting movement and transmit the rotary movement to a carrier via corresponding pins which engage with the carrier. A second drive can include rollers having radial position variation which is prevented from being transmitted to the carrier by providing accommodation at the pin level, either by providing a bushing around the pins with a bore that is eccentric relative to its outer surface, either by engaging the pins into the carriers in portions thereof which are made more flexible. A friction/traction gear at an angle is also disclosed.

A frictional roller reducer having a sun roller; a ring roller; a plurality of intermediate rollers having rolling surfaces coming in rolling contact with the sun roller and the ring roller; the sun roller or the ring roller having a pair of roller elements including inclined surface portions on a circumferential surface coming in rolling with rolling surfaces, the inclined surface portions inclined in directions going toward the intermediate rollers in a radial direction as going away from each other in the axial direction; a pressing device pressing the pair of roller elements in directions going closer to each other, and an elastic member arranged between the pair of roller elements, the elastic member urging the pair of roller elements in directions going away from the rolling surface of the intermediate rollers.

A portable semi-trailer landing-gear motor system and method for use in raising and lowering landing gear on a variety of different semi-trailers by motorized turning of the various-sized drive shafts of the landing gears in appropriate opposing directions, providing motorized performance of an otherwise physically difficult procedure, providing transportability and easy storage within a tractor or truck for use on a variety of semi-trailers in various locations and under various conditions.

A power transmission roller assembly is provided which includes a roller body to be brought into abutment with the driving roller and the driven roller; a pivot shaft fixed to a vehicle body; a pivot arm provided radially inside of the roller body, and pivotally mounted on the pivot shaft; a roller support bearing rotatably supporting the roller body; and a pair of biasing members provided on the pivot arm. The pair of biasing members bias the roller support bearing to a predetermined position between the driving and driven rollers where the abutment forces between the roller body and the driving and driven rollers balance with each other.

A power transmission roller assembly is provided which includes a roller body to be brought into abutment with the driving roller and the driven roller; a pivot shaft fixed to a vehicle body; a pivot arm provided radially inside of the roller body, and pivotally mounted on the pivot shaft; a roller support bearing rotatably supporting the roller body; and a pair of biasing members provided on the pivot arm. The pair of biasing members bias the roller support bearing to a predetermined position between the driving and driven rollers where the abutment forces between the roller body and the driving and driven rollers balance with each other.

A portable, multi-platform friction drive system with a retractable motor drive assembly (12), containing all needed components of an electric friction drive system in a portable handheld case (10), including motor (18), batteries (34), and all associated electronics (36), as well as a mounting system (30) that enables use on popular bike share bicycles (20), personal bicycles, and kick scooters. Its mounting system (30) enables the friction drive system to be easily installed in seconds on many varieties of bicycles or kick scooters, and to be removed just as easily when no longer needed. And by means of its retractable motor assembly (12), the present invention enables the friction drive system to be as compact, clean, and safe as possible so as to be easily carried and stored when not in use.

A portable, multi-platform friction drive system with a retractable motor drive assembly (12), containing all needed components of an electric friction drive system in a portable handheld case (10), including motor (18), batteries (34), and all associated electronics (36), as well as a mounting system (30) that enables use on popular bike share bicycles (20), personal bicycles, and kick scooters. Its mounting system (30) enables the friction drive system to be easily installed in seconds on many varieties of bicycles or kick scooters, and to be removed just as easily when no longer needed. And by means of its retractable motor assembly (12), the present invention enables the friction drive system to be as compact, clean, and safe as possible so as to be easily carried and stored when not in use.

A structure is achieved capable of ensuring excellent transmission efficiency while preventing the occurrence of gross slipping at traction portions.

A pressing device 9 rotationally drives a cam disk 21 by a pressing force adjusting motor 23, which causes an annular roller element 6a of a pair of annular roller elements 6a, 6b to displace in the axial direction. A controller 31, by adjusting the rotational drive of the pressing force adjusting motor 23, adjusts the surface pressure at the traction portions between rolling surfaces 16 of planetary rollers 7 and an inner-diameter side rolling contact surface 5 of an input shaft 3 and outer-diameter side rolling contact surfaces 12a, 12b of the pair of annular roller elements 6a, 6b to a target value.