An automatic transmission[100] system for controlling application of a power source [160] onto a driven-wheel [110] comprises at least two gear-sets [200] mounted on at least one mediating-disk [120], where the mediating-disks [120] are mounted on a dead-axle shaft [210]. The gear-sets [200] has (a) an output-wheel [130] connected to the power source [160] and revolves accordantly; diameter of the output-wheel [130] configured to set transmission-ratio of angular-velocity and torque to be applied to the driven-wheel [110]; the output-wheel [130] is mounted on the dead-axle shaft [210] and set side by side with the mediating-disk [120]; and (b) an Angular-Velocity Engagement Module configured for automatic engagement and disengagement of the output-wheel [130] with the driven-wheel [110]. Each of the output wheels [130] has different diameter, configured for different transmission-ratio of angular-velocity and torque to be applied to the driven-wheel [110].

A multi-speed hub gear, comprising: an axle adapted to be fixed against rotation; a hub shell; a plurality of planetary gear sets, each comprising: a central gear concentrically fixed on the axle, a rotating gear carrier mounting at least one rotating gear to revolve around the center of the central gear; and a ring gear rotated by the at least one rotating gear; wherein a respective the ring gear of one of the sets is mechanically connected to a respective the rotating gear carrier of another of the sets such that the sets rotate in conjunction; and a gear shifter adapted to engage at least one of the sets to the hub shell while disengaging another of the sets from the hub shell.

The present specification relates to a two-speed power transmission for a power tool comprising a planetary gear and a torque responsive gear shift mechanism for directing torque through the planetary gear in a high torque/low speed mode or past the planetary gear in a low torque/high speed mode, and comprising a driving member, a driven member, and a number of coupling elements arranged to intercouple in a first position the driving member and the driven member and in a second position the planetary gear and the driven member, the driving member comprising a number of recesses and axially acting first cam means for cooperation with the coupling elements in the first position forming part thereof. The present specification also relates to power tool comprising such a gear unit and a method for controlling such a power tool.

An automatic transmission may include a rotating shaft; a slider portion provided on the rotating shaft; a first connecting member having one end hinged to the rotating shaft and the other end rising or falling by a centrifugal force as the rotating shaft rotates; a second connecting member having one end hinged to the first connecting member and the other end connected to a slider portion to vertically slide the slider as the first connecting member rises or falls; a diaphragm spring coupled to the slider portion and deformed in an axial direction of the rotating shaft depending on position of the slider portion; a shift fork connected to the slider portion or the diaphragm spring and engaging a synchronizer with a shift stage gear depending on position of the slider portion; an elastic regulator controlling an elastic force of the diaphragm spring; and a controller controlling the elastic regulator.

An axle drive device for a motor vehicle, having at least one drive assembly that is in operative connection with an input shaft of a shift transmission connecting the drive assembly to a wheel axle. The shift transmission a multiple-speed draw key transmission, having a draw key that, in different positions, establishes different transmission ratios between the input shaft and an output shaft of the shift transmission, wherein the draw key is connected to a centrifugal force regulator that shifts the draw key in dependence on a rotational speed of the input shaft or a rotational speed of the output shaft.

A speed reduction ratio automatic switching device includes a planetary gear mechanism. The planetary gear mechanism includes a sun gear provided for an input shaft, planetary gears in mesh with an outer circumferential side of the sun gear, an internal gear in mesh with an outer circumferential side of the planetary gears, and first and second carriers made of a semi-rigid magnetic material. The first and second carriers support the planetary gears in a rotatable manner, and rotate together with the planetary gears along with revolution of the planetary gears. Each of the sun gear, the planetary gears and the internal gear is a helical gear. First and second magnets for generating a thrust force in an axial direction are provided between the first and second carriers and the internal gear.

An automatic transmission may include rotation shaft, sliding unit mounted on the rotation shaft and slidable up and down along the rotation shaft, diaphragm spring coupled to the sliding unit and deformed to be oriented toward first or second end of the rotation shaft along the rotation shaft according to position of the sliding unit, shift fork connected to the sliding unit or the diaphragm spring and configured to cause synchronizer to engage with speed change gear according to the position of the sliding unit, sliding-unit position adjuster connected to the sliding unit and adjusting the position of the sliding unit by causing the sliding unit to slide up or down along the rotation shaft, and controller for controlling the sliding-unit position adjuster to adjust elastic force of the diaphragm spring according to the vehicle speed by causing the sliding unit to slide upward or downward along the rotation shaft.

A multi-speed hub gear, comprising: an axle adapted to be fixed against rotation; a hub shell; a plurality of planetary gear sets, each comprising: a central gear concentrically fixed on the axle, a rotating gear carrier mounting at least one rotating gear to revolve around the center of the central gear; and a ring gear rotated by the at least one rotating gear; wherein a respective the ring gear of one of the sets is mechanically connected to a respective the rotating gear carrier of another of the sets such that the sets rotate in conjunction; and a gear shifter adapted to engage at least one of the sets to the hub shell while disengaging another of the sets from the hub shell.

A dry type of torque converter for an electric vehicle and a control method thereof are disclosed.

The dry type of torque converter for the electric vehicle according to an exemplary embodiment of the present invention includes: a planetary gear including a first element connected to an input shaft, a second element connected to an output shaft, and a third element variably connected to a fixing unit; at least one eddy current torque generation unit provided between the first element and the second element and generating an eddy current to be controlled by a speed of the output shaft; a front cover integrally connected to the input shaft and the first element and incorporating the planetary gear; a one-way clutch interlocking one-direction connection of the third element and the fixing unit and connecting them to each other; a back cover provided at the output shaft side to be coupled with the front cover; and a lock-up mechanism respectively provided on both sides of the second element based on an axis direction and directly connecting the input shaft and the output shaft while being respectively in selective contact with the inner surfaces of the front cover and the back cover by the centrifugal force generated depending on the rotation speed of the output shaft.

A speed reduction ratio automatic switching device includes a planetary gear mechanism. The planetary gear mechanism includes a sun gear provided for an input shaft, planetary gears in mesh with an outer circumferential side of the sun gear, an internal gear in mesh with an outer circumferential side of the planetary gears, and first and second carriers made of a semi-rigid magnetic material. The first and second carriers support the planetary gears in a rotatable manner, and rotate together with the planetary gears along with revolution of the planetary gears. Each of the sun gear, the planetary gears and the internal gear is a helical gear. First and second magnets for generating a thrust force in an axial direction are provided between the first and second carriers and the internal gear.