Speed-changing transmission hub for a bicycle
AssigneeIndustrial Technology Research Institute
InventorsYu-Ming Huang, Jung-Ping Chiang, Caesar Chen, Ching-Huei Wu
Life of this patent
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Abstract
The present invention relates to a speed-changing transmission hub for a bicycle comprising: a central shaft; a controlling device; a planetary gear system, which comprises a planet gear holder, holding several planet gears; a second ring gear; a first ring gear; and two sun gears. Variations of speed are realized by separately fixing the sun gears of different diameters. There is no switching of input and no reversal of the rotation of the sun gears. The sun gears only need to be controlled by a one-way clutch guided by the controlling device, which is mounted on the central shaft. Thereby the arrangement is simplified and its weight is reduced.
Claims9
A speed-changing transmission hub for a bicycle, comprising:
- a central shaft, with an axis that defines a longitudinal axis with a front end and a rear end, having a periphery, into which two accommodating holes are cut at two longitudinal positions;
- a controlling device with a front end and a rear end, surrounding said central shaft, further comprising
- a controlling element on said front end with an angular position controlled by a user, and
- a tube with a front end, a rear end and a periphery, having an angular position that follows said angular position of said controlling element, with two openings cut into said periphery of said tube at said two longitudinal positions of said two accommodating holes;
- a one-way clutch group, comprising two clutches, which are inserted into said two accommodating holes, each of said two clutches either outward protruding through one of said openings of said tube beyond said periphery thereof, or by said tube held back in one of said accommodating holes;
- two sun gears, surrounding said tube at said two longitudinal positions of said two accommodating holes, having a rotational axis coinciding with said longitudinal axis, separately rotatable against said tube and separately engaging or disengaging with said two clutches, as controlled by said angular position of said tube;
- a planet gear system, further comprising
- a carrier, having a large opening with a periphery, surrounding said two sun gears, having an axis coinciding with said longitudinal axis, rotatably mounted on said tube close to said rear end thereof, with several openings in said periphery of said large opening, and
- several planet gears, rotatably mounted in said openings of said carrier, each of said planet gears a first gear portion and a second gear portion, which engage with said two sun gears, respectively, revolving around said sun gears;
- a first ring gear, having an axis coinciding with said longitudinal axis, engaging with said planet gears;
- a first transmission unit for transmitting input torque to said first ring gear;
- and
- an output unit, surrounding said rear end of said tube, for transmitting torque from said carrier to an output hub;
- wherein said planet gears are driven only by said first ring gear, with each of said two sun gears being either fixed or rotating the same way, and gears are switched by separately fixing and releasing said two sun gears using said one-way clutch group, as controlled by said angular position of said tube.
Dependencies are inferred from the claim text.