A friction-type continuously variable transmission includes first to third rolling elements of which are annular and is centered on a principal axis, planetary rollers arranged in a circumferential direction about the principal axis, support pins arranged to rotatably support the planetary rollers, and a planetary roller support portion arranged to support each support pin such that the support pin is capable of inclining in a section including the principal axis. Each planetary roller includes a recessed portion in the shape of a circular ring in an outer circumference thereof centered on the support pin. The first rolling element is arranged to make contact with a rolling contact surface of the planetary roller from one side in a radial direction axially below the recessed portion. The first rolling element is arranged to make contact with the rolling contact surface of the planetary roller from the one side in the radial direction axially above the recessed portion. The third rolling element is arranged to make contact with the recessed portion of the planetary roller from an opposite side in the radial direction, and is supported to be capable of moving in a vertical direction relative to the planetary roller support portion.

A transmission includes a first shaft which is rotatably supported by a first radial bearing, a ring member which is connected to an end portion of the first shaft, a sun roller which is disposed inside the ring member in a radial direction, a second shaft which extends from the sun roller, a plurality of planetary rollers which are disposed in a state of being in contact with an inner peripheral surface of the ring member and an outer peripheral surface of the sun roller, and a planetary roller supporting member which rotatably supports the planetary roller and restrains a movement of the planetary roller in the circumferential direction, in which the ring member is in contact with the plurality of planetary rollers in a state of pressing the plurality of planetary rollers inward in the radial direction so that the plurality of planetary rollers face the sun roller.

A transmission includes a first shaft which is rotatably supported by a first radial bearing, a ring member which is connected to an end portion of the first shaft, a sun roller which is disposed inside the ring member in a radial direction, a second shaft which extends from the sun roller, a plurality of planetary rollers which are disposed in a state of being in contact with an inner peripheral surface of the ring member and an outer peripheral surface of the sun roller, and a planetary roller supporting member which rotatably supports the planetary roller and restrains a movement of the planetary roller in the circumferential direction, in which the ring member is in contact with the plurality of planetary rollers in a state of pressing the plurality of planetary rollers inward in the radial direction so that the plurality of planetary rollers face the sun roller.

In a cycloid transmission a second input side eccentric cam and a first output side eccentric cam are integrally fixed to a rotary shaft to be eccentric in the same phase, a first input side eccentric cam is fixed to the rotary shaft so that the first input side eccentric cam is eccentric in a phase different from that of the second input side eccentric cam and that of the first output side eccentric cam, a second output side eccentric cam is rotatably attached to the rotary shaft, a second input side cycloid gear and a first output side cycloid gear are integrally formed to be rotated in synchronism with each other in the same phase, and a first input side cycloid gear is connected to the second output side cycloid gear by a connection member to be rotated in synchronism with each other in the same phase.

In a cycloid transmission a second input side eccentric cam and a first output side eccentric cam are integrally fixed to a rotary shaft to be eccentric in the same phase, a first input side eccentric cam is fixed to the rotary shaft so that the first input side eccentric cam is eccentric in a phase different from that of the second input side eccentric cam and that of the first output side eccentric cam, a second output side eccentric cam is rotatably attached to the rotary shaft, a second input side cycloid gear and a first output side cycloid gear are integrally formed to be rotated in synchronism with each other in the same phase, and a first input side cycloid gear is connected to the second output side cycloid gear by a connection member to be rotated in synchronism with each other in the same phase.

An electric drive includes a motor and a transmission for transferring torque from the motor to a tool. The transmission includes a plurality of planetary rollers which are driven by a rotary shaft of the motor, and an output ring which is connectable to the tool, and which is driven by the planetary rollers. The transmission further includes a roller casing which is secured to a housing of the motor, and which supports parallel planetary shafts upon which the planetary rollers are mounted for rotation relative to the roller casing, and a bearing having an inner race which engages the roller casing, and an outer race which engages the inner periphery of the output ring.

An electric drive includes a motor and a transmission for transferring torque from the motor to a tool. The transmission includes a plurality of planetary rollers which are driven by a rotary shaft of the motor, and an output ring which is connectable to the tool, and which is driven by the planetary rollers. The transmission further includes a roller casing which is secured to a housing of the motor, and which supports parallel planetary shafts upon which the planetary rollers are mounted for rotation relative to the roller casing, and a bearing having an inner race which engages the roller casing, and an outer race which engages the inner periphery of the output ring.

A nutational cycloidal reducer reduces an input speed to an output speed by a reduction ratio. The reducer includes a timing ring having an internal wall with a series of longitudinally extending tooth profiles, an output connected to the timing ring, a pulley having a central opening, a series of longitudinally extending tooth profiles and a plurality of circumferentially disposed pin bores. An input shaft has first and second shaft portions. The first portion is concentric with a longitudinal axis and the second portion is eccentric to the axis. A plate has a central opening. The pulley is positioned in the timing ring with some of the pulley and timing ring tooth profiles engaged with each other. The second shaft portion is positioned in the pulley and the plate and drives the pulley in a nutational movement. The pulley has one or more less tooth profiles than the timing ring, such that the reduction ratio is defined by # of timing ring tooth profiles/(# of timing ring tooth profiles−# of pulley tooth profiles).

A nutational cycloidal reducer reduces an input speed to an output speed by a reduction ratio. The reducer includes a timing ring having an internal wall with a series of longitudinally extending tooth profiles, an output connected to the timing ring, a pulley having a central opening, a series of longitudinally extending tooth profiles and a plurality of circumferentially disposed pin bores. An input shaft has first and second shaft portions. The first portion is concentric with a longitudinal axis and the second portion is eccentric to the axis. A plate has a central opening. The pulley is positioned in the timing ring with some of the pulley and timing ring tooth profiles engaged with each other. The second shaft portion is positioned in the pulley and the plate and drives the pulley in a nutational movement. The pulley has one or more less tooth profiles than the timing ring, such that the reduction ratio is defined by # of timing ring tooth profiles/(# of timing ring tooth profiles−# of pulley tooth profiles).

A transmission arrangement includes an input shaft, an output shaft, an outer race mounted on one end of one of the input and output shafts, an inner race mounted on one end of the other of the input and output shafts, ball bearings, and first and second finger assists. The inner and outer races are arranged to create a cage. The ball bearings are disposed within the cage and spaced apart from each other. The first finger assist is mounted to press at least a first one of the ball bearings into position within the cage. The second finger assist is mounted to press at least a second one of the ball bearings into position within the cage. The second finger assist is disposed in registration with the first finger assist.