Continuously variable speed transmission for bicycles

Abstract

Providing a continuously variable bicycle transmission improves bicycle functionality and increases the reliability and lifespan of the transmission. The transmission is capable of infinitely variable speeds among a potentially infinite number of speed ratios, allowing the user to select the appropriate speed ratio based on driving conditions, bicycle motion, and other user considerations. The drive assembly reduces torque from the crankshaft to a series of sheaves and belts, improving the reliability and lifespan of the transmission components that set the speed ratio. Furthermore, the position motor controls the relative position between the sheaves, thereby easily and accurately controlling the speed ratio. The driven assembly increases the output torque to the drive wheel that propels the bicycle.

Description

Technical Field

[0001] Cross-Reference to Related Applications for Bicycle Continuously Variable Transmissions The present application claims the benefit of U.S. Provisional Patent Application No. 63 / 421,031, filed on October 31, 2022, which is hereby incorporated by reference in its entirety. The present invention particularly relates to continuously variable transmissions for bicycles, and to a continuously variable transmission having the capability of transmitting power from a crankshaft to a rear hub at a stepless speed ratio.

Background Art

[0002] Some conventional bicycles are provided with a chain connecting one sprocket on a crankshaft to one sprocket on a rear hub, which transmits power generated by a rider pedaling the crankshaft to a rear wheel mounted to the rear hub, thereby propelling the bicycle forward. However, if there is only one sprocket on the crankshaft and one sprocket on the rear hub, there is only one gear ratio for transmitting power to the rear wheel on the rear hub. While this gear ratio can be optimized for a narrow range of operating conditions of the bicycle, it cannot be optimized for a plurality of ranges of operating conditions. For example, in the case of a high gear ratio where the rear hub sprocket has a relatively large number of teeth, the torque for moving the bicycle from a stationary state is large, but the rider's ability to travel at high speed on the bicycle is limited. Conversely, a low gear ratio where the rear hub sprocket has a relatively small number of teeth is suitable for high speed travel, but provides poor performance when the rider starts the bicycle from a stationary state.

[0003] To address this issue, conventional bicycles feature multiple sprockets on the crankshaft or rear hub, allowing for multiple gear ratios between the crankshaft and rear hub. This enables the rider to start with a high gear ratio when the bicycle is stationary, providing greater torque to propel the bike from a standstill. The derailleur then shifts the chain connecting the crankshaft and rear hub from one sprocket on the crankshaft or rear hub to another, achieving a lower gear ratio. As a result, the rider can further increase the bicycle's speed, much like a conventional car shifting gears as it increases. However, even with multiple gears, the number of gear ratios the rider can choose from is very limited. These gear ratios are optimized only for specific operating conditions and may not be suitable for all riders. Furthermore, multiple sprockets, derailleurs, and other shifting components increase the complexity, weight, and potential for failure of the bicycle.

[0004] In another conventional system, multiple spur gears or helical gears are arranged on the crankshaft. This gear system operates like a car's transmission, requiring a complex shifter to change gear ratios. Similar to the sprockets and derailleurs mentioned earlier, this gear system can only switch between a very limited number of gear ratios, and is complex, heavy, and expensive.

[0005] In contrast to sprocket and derailleur systems and crankshaft gear systems, the embodiments described herein do not use sprockets or gears for a limited number of gear ratios. Instead, the embodiments described herein feature multiple sheave sets connected by belts and capable of moving at countless speed ratios, allowing the user to precisely select a speed ratio suitable for the current operating conditions. "Speed ​​ratio" represents the relative mechanical advantage between the sheave sets and is analogous to a gear ratio.

[0006] Other conventional power transmission systems can also be installed in the rear hub of a bicycle. One such system features planetary gears within the rear hub, using a sensitive shifter to change the gear ratio, and requires the bicycle to be moving while coasting without power input for the shifter to change the gear ratio. As described herein, this embodiment includes a position motor that precisely controls the speed ratio. Furthermore, the position motor can control the speed ratio and maintain a specific speed ratio during operation.

[0007] Another conventional system located in the rear hub uses a continuously variable mechanism with a rotating ball ring to continuously change the gear ratio, or speed ratio, between the system's input and output. However, this system requires special traction oil, has high internal forces that reduce the system's reliability and lifespan, and is heavy, inefficient, and expensive. This embodiment provides a continuously variable transmission that does not require special oil and reduces internal forces to improve the reliability and lifespan of the transmission. Specifically, the drive assembly described herein reduces the torque on the sheaves and belt by increasing their rotational speed, thereby reducing damage and improving the reliability and lifespan of the transmission. [Overview of the project]

[0008] This embodiment relates to a novel transmission that enables the speed ratio between the input crankshaft and the output drive wheel to be continuously varied in a stepless speed ratio. Furthermore, this embodiment offers more precise control of the speed ratio, greater reliability, and a longer lifespan. While many of the embodiments described herein relate to transmissions for bicycles, the transmissions of this embodiment are applicable to any small human-powered or electric vehicle equipped with a transmission.

[0009] One aspect of the various embodiments described herein provides a continuously variable transmission comprising multiple sheave sets and a belt, capable of infinitely changing speed ratios in a stepless manner, allowing a user to control the speed ratio to suit specific operating conditions of a bicycle. One sheave set is arranged around a crankshaft rotatable around a crank axis, and the other sheave set is arranged around a countershaft rotatable around a counter axis parallel to the crank axis. Power is transmitted via a belt from the sheave set around the crankshaft, i.e., the drive sheaves, to the sheave set around the countershaft, i.e., the driven sheaves. Each sheave set has a fixed sheave that rotates around the shaft but does not move along the shaft, and a movable sheave that rotates around the shaft and moves along the shaft.

[0010] To change the speed ratio between multiple sheave sets and the overall speed ratio of the transmission, one of the movable sheaves changes position along its respective shaft. For example, as the movable driven sheave approaches the fixed driven sheave, the belt moves to contact the inner surface of the driven sheave that is further away from the countershaft. The movable drive sheave moves in accordance with the change in the belt's position, thereby setting a high speed ratio. Conversely, as the movable driven sheave moves further away from the fixed driven sheave, the belt moves to contact the inner surface of the driven sheave that is closer to the countershaft. In this case as well, the movable drive sheave moves in accordance with the change in the belt's position, thereby setting a low speed ratio. The biasing members acting on the movable drive sheaves respond to these changes in speed ratios, as will be described in more detail herein.

[0011] One embodiment of the embodiments described herein provides a position motor for convenient and precise control of the position of a movable driven sheave along the counter axis to set the speed ratio of a transmission. The position motor may be, for example, a servo motor with an output shaft rotatable around an axis. In various embodiments, an eccentric cam is connected to the output shaft and a hub is connected to the movable driven sheave. The eccentric cam is located in a recess of the hub, and as the output shaft and eccentric cam rotate, the hub and movable driven sheave move along the counter axis to set the speed ratio. Thus, the position motor can change the speed ratio over a range of bicycle speeds and inputs and maintain a desired speed ratio. Furthermore, the position motor can change the speed ratio while the bicycle is stopped or in motion and / or while the user is pedaling to power the transmission or simply coasting.

[0012] Further aspects of some embodiments of this specification relate to reducing the torque acting on the sheaves and belts, thereby improving the reliability and lifespan of the transmission. Generally, in a transmission, force or torque is inversely proportional to speed, with an increase in torque associated with a decrease in speed and a decrease in torque associated with an increase in speed. When high torque acts on the sheaves and belts, the lifespan of these components is shortened. Furthermore, when high torque acts on the sheaves, the position motor and other components may be damaged. Therefore, increasing the speed reduces the torque on the sheaves and belts. The drive assembly transmits torque from the crankshaft to the drive sheaves, and the drive assembly increases the rotational speed of the sheaves compared to the crankshaft while reducing the torque, thereby improving the reliability and lifespan of the transmission.

[0013] The drive assembly can be positioned to accommodate various constraints of a bicycle. For example, an embodiment of the derailleur is located on the bottom bracket of the bicycle frame where the user engages the pedals with the crankshaft, and some components of the derailleur are positioned around the crankshaft. Therefore, some components of the derailleur are constrained by certain dimensions, such as the distance between the crank arms that connect the pedals to the crankshaft, or the clearance distance between the bottom bracket and the ground. Thus, in various embodiments, the drive assembly comprises two planetary gear sets connected in series to transmit power from the crankshaft to the drive sheave. In these embodiments, the drive assembly may also be called a drive gear assembly. Using two planetary gear sets allows for the necessary torque reduction while keeping the form factor of the derailleur sufficiently compact. However, it should be understood that the present invention includes embodiments of bicycle derailleurs with more or fewer gear sets, or with other components such as sprockets or belts, and also includes embodiments of derailleurs for other vehicles subject to other practical constraints.

[0014] A further embodiment of the embodiments herein provides a driven assembly and output gear that transmit power from a driven sheave and countershaft to a drive wheel, thereby driving the rear wheel to propel the vehicle. The rotational speed of the sheave and belt is increased to reduce torque in the transmission, but the torque needs to be increased to enable the drive wheel to propel the vehicle. The driven assembly is positioned around the countershaft and engages with the countershaft. The driven assembly can be one or more planetary gear sets that reduce speed and increase torque. In these embodiments, the driven assembly is a driven gear assembly. And in some embodiments, the output of the driven gear assembly is engaged with a first output gear positioned around the countershaft. Another second output gear is positioned around the crankshaft and engages with the first output gear. Finally, in various embodiments, the second output gear transmits power to the drive wheel to propel the bicycle. In some embodiments, it will be understood that a belt transmits power from the drive assembly to the driven sheave, or that the driven assembly includes components such as a sprocket and a belt.

[0015] Further embodiments of the embodiments described herein provide controllers for adjusting and operating various components of a transmission, particularly the position motor. In some embodiments, the transmission includes a battery that communicates with the controller to power the position motor, and a generator that engages with the rotating parts of the transmission to transmit power to the battery. The controller can determine the amount of power to be transmitted to the position motor based on one or more input signals. Furthermore, the controller can transmit output signals to the position motor to control the position motor in various ways, such as the speed or acceleration of the output shaft or the direction of rotation of the output shaft.

[0016] Various devices can send one or more input signals to a controller, for example, to change the speed ratio of a gearbox. For instance, a shifter mounted on a bicycle handlebar can send an input signal to the controller. When a user moves a dial or paddle, a position sensor detects the movement and sends an input signal to the controller. Similarly, a torque sensor detects the torque applied by the user to the crankshaft and sends an input signal to the controller. The controller can process one or more input signals and controls the flow of power to the position motor and the output signal to the position motor to set the appropriate speed ratio for the gearbox.

[0017] One embodiment of the specifications provides a continuously variable transmission having a drive sheave set arranged around a countershaft and a driven sheave set arranged around a crankshaft. The drive assembly transmits power from the crankshaft to the countershaft, and the countershaft transmits power to the drive sheaves. The drive sheaves then transmit power to the driven sheaves via belts, and the driven sheaves transmit power to the drive wheels, for example, via a driven assembly. This configuration, along with a position motor positioned adjacent to the movable drive sheaves, reduces the number and complexity of parts. The position motor controls the speed ratio of the transmission by controlling the position of the movable drive sheaves, resulting in improved responsiveness to user input and faster changes in the speed ratio.

[0018] In embodiments where the drive sheave is positioned around the countershaft, and in other embodiments, the drive assembly and driven assembly may comprise multiple gears, sprockets, belts, etc., for power transmission. In some embodiments, the drive assembly comprises a first gear positioned around the crankshaft, a second gear positioned around the intermediate shaft and meshing with the first gear, a third gear positioned around the intermediate shaft, and a fourth gear positioned around the countershaft and meshing with the third gear. Thus, power is transmitted from the crankshaft to the first gear, which drives the second gear and the intermediate shaft. The intermediate shaft then transmits power to the third gear, the fourth gear, and the countershaft. These gears are sized and positioned so that the countershaft rotates at a higher speed and with lower torque than the crankshaft, thereby reducing wear on the transmission components.

[0019] Similarly, the driven assembly may comprise multiple gears, sprockets, belts, etc., for power transmission. In some embodiments, the driven assembly comprises a sun gear, planetary gears, a carrier connected to the planetary gears, and a ring gear, which receive power from the driven sheave. The carrier acts as the output of the driven assembly, transmitting power to the drive wheel so that the drive wheel rotates at a slower speed and higher torque than the driven sheave. In other embodiments, the driven assembly spans between the countershaft and the crankshaft, with a first sprocket positioned around the countershaft and a second sprocket positioned around the crankshaft, and a synchronous belt connecting these sprockets. Power is transmitted from the countershaft to the first sprocket, the belt, and then to the second sprocket, which transmits power to the drive wheel so that the drive wheel rotates at a slower speed and higher torque than the countershaft.

[0020] A first aspect of this specification provides a continuously variable transmission for a bicycle, comprising a crankshaft rotatable around a crank axis, a drive gear assembly positioned around the crankshaft, wherein the input to the drive gear assembly is coupled to the crankshaft, and the output of the drive gear assembly is configured to rotate faster and with lower torque than the crankshaft, a driven sheave set positioned around the crankshaft and coupled to the output of the drive gear assembly, a countershaft rotatable around a counter axis, a drive sheave set positioned around the countershaft and engaged with the countershaft, and a belt connecting the drive sheave set and the driven sheave set and configured to transmit power from the drive sheave set to the driven sheave set, wherein the speed ratio between the drive sheave set and the driven sheave set is continuously variable, and comprising a driven gear assembly positioned around the countershaft, wherein the input to the driven gear assembly is coupled to the countershaft, and the output of the driven gear assembly is configured to rotate slower and with greater torque than the countershaft, and the output of the driven gear assembly is configured to transmit power to the drive wheel to propel the bicycle.

[0021] A transmission in the first embodiment optionally includes a position motor, and the driven sheave set comprises a fixed sheave and a movable sheave that engages with the position motor, and the position motor is configured to move the movable sheave along the counter shaft to change the speed ratio between the drive sheave set and the driven sheave set.

[0022] A transmission of the first embodiment may include one or more of the embodiments described above and selectively a biasing member, wherein the drive sheave set comprises a fixed sheave and a movable sheave, the biasing member is configured to act on the movable sheave along the crankshaft, and the movable sheave is configured to change position along the crankshaft to adjust to a speed ratio set by the driven sheave set.

[0023] A transmission of the first embodiment may include one or more of the embodiments described above, optionally, a drive gear assembly comprising a first planetary gear set having a ring gear, a plurality of first planetary gears, a first carrier, and a first sun gear, wherein the first carrier is the input to the drive gear assembly and is configured to drive a plurality of first planetary gears between the ring gear and the first sun gear to rotate the first sun gear faster and with lower torque than the crankshaft; a second planetary gear set comprising a plurality of second planetary gears, a second carrier, and a second sun gear, wherein the second carrier engages with the first sun gear and is configured to drive a plurality of second planetary gears between the ring gear and the second sun gear to rotate the second sun gear faster and with lower torque than the first sun gear, and the second sun gear is the output to the drive gear assembly.

[0024] A transmission of the first embodiment may include one or more of the embodiments described above, optionally having a first planetary gear set with a gear ratio and a second planetary gear set with a gear ratio between approximately 1:3.5 and 1:4.5.

[0025] A transmission of the first embodiment may include one or more of the embodiments described above, optionally, the driven gear assembly comprising a planetary gear set having a ring gear, a plurality of planetary gears, and a sun gear, wherein the sun gear is the input to the driven gear assembly and is configured to drive the plurality of planetary gears, the plurality of planetary gears are configured to drive the ring gear at a lower speed and with higher torque than the sun gear, and the ring gear is the output to the driven gear assembly.

[0026] A transmission of the first embodiment comprises one or more of the embodiments described above, and optionally a drive wheel positioned around a crankshaft, and an output gear positioned around a crankshaft and engaging with the drive wheel, wherein teeth extending around the outer surface of the ring gear are configured to transmit power to the output gear, and the output gear is configured to transmit power to the drive wheel to propel the bicycle.

[0027] A second aspect of the present specification is to provide a continuously variable transmission system for bicycles, comprising: a crankshaft rotatable about a crank axis; a fixed drive sheave and a movable drive sheave disposed around the crankshaft, the fixed drive sheave and the movable drive sheave configured to receive power from the crankshaft; a counter shaft rotatable about a counter axis; a fixed driven sheave and a movable driven sheave disposed around the counter shaft; and a belt connecting the fixed drive sheave and the movable drive sheave to the fixed driven sheave and the movable driven sheave, the belt configured to transmit power from the fixed drive sheave and the movable drive sheave to the fixed driven sheave and the movable driven sheave, wherein a speed ratio between the fixed drive sheave and the movable drive sheave and the fixed driven sheave and the movable driven sheave is continuously variable; the transmission system further comprises a biasing member configured to act on the movable drive sheave along the crank axis, the movable drive sheave changes position along the crank axis to accommodate the speed ratio set by the fixed driven sheave and the movable driven sheave; and a position motor engaged with the movable driven sheave, the position motor configured to move the movable driven sheave along the counter axis to change the speed ratio between the fixed drive sheave and the movable drive sheave and the fixed driven sheave and the movable driven sheave.

[0028] In the transmission according to the second aspect, optionally, the position motor may be a servo motor having an output shaft, and rotation of the output shaft is configured to move the movable driven sheave along the counter axis.

[0029] The transmission according to the second aspect, in combination with one or more of the foregoing embodiments, may optionally include an eccentric cam connected to the output shaft of the servo motor and a hub connected to the movable driven sheave, wherein the eccentric cam extends into a recess of the hub, rotation of the output shaft rotates the eccentric cam, and the hub and the movable driven sheave move along the counter axis, thereby changing the speed ratio between the fixed drive sheave and the movable drive sheave and the fixed driven sheave and the movable driven sheave.

[0030] A transmission of a second embodiment may optionally include one or more of the embodiments described above, a controller communicating with a position motor, and a shifter communicating with the controller, the shifter being configured to transmit an input signal to the controller, and the controller being configured such that the position motor moves a movable driven sheave along a counter axis to change the speed ratio between the fixed driven sheave and the movable driven sheave and the fixed driven sheave and the movable driven sheave.

[0031] A transmission in a second embodiment may optionally include one or more of the embodiments described above, a controller communicating with a position motor, and a torque sensor operably engaged with a crankshaft and communicating with the controller, wherein the torque sensor is configured to transmit an input signal to the controller, and the controller is configured such that the position motor moves a movable driven sheave along a countershaft to change the speed ratio between the fixed driven sheave and the movable driven sheave and the fixed driven sheave and the movable driven sheave.

[0032] A transmission of a second embodiment may optionally include one or more of the embodiments described above, and a plurality of pins protruding from the countershaft and a plurality of slots extending through a portion of a movable driven sheave, wherein the plurality of pins are arranged in each of the plurality of slots such that the movable driven sheave is movable relative to the countershaft along the counter axis.

[0033] A transmission of the second embodiment includes one or more of the embodiments described above, wherein each of the multiple slots may optionally extend along a line that is not parallel to the counter axis.

[0034] A transmission of the second embodiment may include one or more of the embodiments described above, wherein the portion of the movable driven sheave having slots may be a portion arranged around the cylindrical portion and / or countershaft.

[0035] The transmission of the second embodiment may include one or more of the embodiments described above, wherein the portion of the movable driven sheave having a slot is a portion that does not come into contact with the belt.

[0036] A third aspect of this specification provides a continuously variable transmission for a bicycle, comprising a housing extending from a first side to a second side, a fixed drive sheave and a movable drive sheave rotatable around a crankshaft, the movable drive sheave being positioned between the first side of the housing and the fixed drive sheave, a countershaft at least partially positioned within the housing and rotatable around a countershaft, and a fixed driven sheave and a movable driven sheave positioned around the countershaft, the fixed driven sheave being positioned between the first side of the housing and the movable driven sheave, and the countershaft It comprises a plurality of pins protruding from and a plurality of slots extending through a movable driven sheave, the plurality of pins being positioned in each of the plurality of slots such that the movable driven sheave is movable relative to the countershaft along the counter axis, and a belt connecting two drive sheaves and two driven sheaves, the belt configured to transmit power from the two drive sheaves to the two driven sheaves, the speed ratio between the two drive sheaves and the two driven sheaves being continuously variable, and configured so that power is transmitted to the countershaft to propel the bicycle.

[0037] The transmission of the third embodiment may optionally have a portion of the movable driven sheave having slots arranged around the cylindrical portion and / or countershaft.

[0038] A third embodiment of the transmission may include one or more of the embodiments described above, wherein the portion of the movable driven sheave having a slot is a portion that does not come into contact with the belt.

[0039] A third embodiment of the transmission comprises one or more of the embodiments described above and, optionally, a position motor that engages with a movable driven sheave, the position motor being configured to move the movable driven sheave along a countershaft to change the speed ratio between two drive sheaves and two driven sheaves, and includes a biasing member configured to act on the movable drive sheave along a crankshaft, the movable drive sheave being configured to change position along the crankshaft to correspond to the speed ratio set by the two driven sheaves.

[0040] A third embodiment of the transmission may include one or more of the embodiments described above, and optionally a drive gear assembly positioned between a first side of the housing and a movable drive sheave, wherein the input to the drive gear assembly is configured to receive power from the crankshaft, and the output to the drive gear assembly is configured to rotate faster and with less torque than the crankshaft, and the two drive sheaves are coupled to the output to the drive gear assembly.

[0041] A third embodiment of the transmission may include one or more of the embodiments described above, and optionally a driven gear assembly positioned around a countershaft between a first side of the housing and a fixed driven sheave, wherein the input of the driven gear assembly engages with the countershaft, and the output of the driven gear assembly is configured to rotate at a lower speed and with higher torque than the countershaft.

[0042] A third embodiment of the transmission includes one or more of the embodiments described above, wherein the drive gear assembly and the driven gear assembly are optionally located in a sealed portion of a housing that is at least partially filled with lubricant.

[0043] A third embodiment of the transmission may include one or more of the embodiments described above, wherein the belt has a V-shaped cross-section, and the inner surfaces of the two drive wheels and the inner surfaces of the two driven sheaves are tapered to complement the sides of the V-shaped belt.

[0044] A fourth aspect of this specification provides a continuously variable transmission for a bicycle, comprising a crankshaft rotatable around a crankshaft, a countershaft rotatable around a countershaft, and a drive assembly having an input linked to the crankshaft and an output linked to the countershaft, wherein the crankshaft drives the drive assembly, and the drive assembly drives the countershaft, causing the countershaft to rotate at a higher speed and with lower torque than the crankshaft, comprising a drive sheave set arranged around the countershaft and engaged with the countershaft, a driven sheave set arranged around the crankshaft, and a belt connecting the drive sheave set and the driven sheave set and configured to transmit power from the drive sheave set to the driven sheave set, wherein the speed ratio between the drive sheave set and the driven sheave set is continuously variable, comprising a driven assembly arranged around the crankshaft, wherein the input of the driven assembly is linked to the driven sheave set, and the output of the driven assembly is configured to rotate at a lower speed and with higher torque than the driven sheave set, and the output of the driven assembly is configured to transmit power to propel the bicycle.

[0045] A transmission in a fourth embodiment may optionally include a position motor, the drive sheave set comprising a fixed sheave and a movable sheave that engages with the position motor, the position motor being configured to move the movable sheave along a counter axis to change the speed ratio between the drive sheave and the driven sheave set.

[0046] A fourth embodiment of the transmission may optionally include one or more of the embodiments described above, and a biasing member, wherein the driven sheave set comprises a fixed sheave and a movable sheave, the biasing member is configured to act on the movable sheave along the crankshaft, and the movable sheave is configured to change position along the crankshaft to correspond to the speed ratio set by the driven sheave set.

[0047] A fourth embodiment of the transmission may include one or more of the embodiments described above, optionally comprising: a drive assembly comprising a first gear positioned around a crankshaft and being an input to the drive assembly; a second gear positioned around an intermediate shaft and engaging with the intermediate shaft, wherein the crankshaft drives the first gear, and the first gear drives the second gear, so that the intermediate shaft rotates faster and with less torque than the crankshaft; a third gear positioned around the intermediate shaft and engaging with the intermediate shaft; and a fourth gear positioned around a countershaft and being an output to the drive assembly, wherein the intermediate shaft drives the third gear, and the third gear drives the fourth gear, so that the countershaft rotates faster and with less torque than the intermediate shaft.

[0048] A transmission of the fourth embodiment includes one or more of the embodiments described above, and optionally, the gear ratio between the input and output of the drive assembly may be between approximately 1:3.8 and 1:14.5.

[0049] A fourth embodiment of the transmission may include one or more of the embodiments described above, in which the driven assembly comprises a planetary gear set having a ring gear, a plurality of planetary gears, a carrier connecting the plurality of planetary gears, and a sun gear, the sun gear being the input to the driven assembly and configured to drive the plurality of planetary gears relative to the ring gear such that the carrier rotates slower than the sun gear and with greater torque, the carrier being the output to the driven assembly.

[0050] A fourth embodiment of the transmission may include one or more of the embodiments described above, wherein the driven assembly comprises a first sprocket which is the input to the driven assembly, a second sprocket which is the output to the driven assembly, and a belt which connects the first sprocket and the second sprocket.

[0051] A fifth aspect of the present disclosure provides a continuously variable transmission system for a bicycle, comprising a crankshaft rotatable around a crank axis, a countershaft rotatable around a counter axis, a fixed drive sheave and a movable drive sheave arranged around the countershaft, the fixed drive sheave and the movable drive sheave configured to receive power from the countershaft, a fixed driven sheave and a movable driven sheave arranged around the crankshaft, and a belt connecting the fixed drive sheave and the movable drive sheave to the fixed drive sheave and the movable driven sheave, the belt moving from the fixed drive sheave and the movable drive sheave to the fixed drive sheave and the movable driven sheave The system is configured to transmit power to a sheave, and the speed ratio between the fixed drive sheave and the movable drive sheave and the fixed driven sheave and the movable driven sheave is continuously variable, and includes a biasing member configured to act on the movable driven sheave along the crankshaft, the movable driven sheave having a position motor that changes position along the crankshaft to correspond to the speed ratio set by the fixed drive sheave and the movable drive sheave, the position motor being configured to move the movable drive sheave along the countershaft to change the speed ratio between the fixed drive sheave and the movable drive sheave and the fixed driven sheave and the movable driven sheave.

[0052] In the fifth embodiment of the transmission, the position motor may optionally be a servo motor with an output shaft, and the rotation of the output shaft may cause a movable drive sheave to move along the counter shaft.

[0053] A fifth embodiment of the transmission may optionally include one or more of the embodiments described above, an eccentric cam connected to the output shaft of a servo motor, and a hub configured to move along a counter axis, the eccentric cam extending into a recess of the hub, the rotation of the output shaft causing the eccentric cam to rotate, the hub moving a movable drive sheave along the counter axis, and changing the speed ratio between the fixed drive sheave and the movable drive sheave and the fixed driven sheave and the movable driven sheave.

[0054] A fifth embodiment of the transmission may optionally include one or more of the embodiments described above, a controller communicating with a position motor, and a shifter communicating with the controller, the shifter being configured to transmit an input signal to the controller, and the controller being configured such that the position motor moves a movable drive sheave along a counter axis to change the speed ratio between the fixed drive sheave and the movable drive sheave and the fixed driven sheave and the movable driven sheave.

[0055] A fifth embodiment of the transmission may optionally include one or more of the embodiments described above, a controller communicating with a position motor, and a torque sensor operably engaged with the crankshaft and communicating with the controller, wherein the torque sensor is configured to transmit an input signal to the controller, and the controller is configured such that the position motor moves a movable drive sheave along a countershaft to change the speed ratio between the fixed drive sheave and the movable drive sheave and the fixed driven sheave and the movable driven sheave.

[0056] A fifth embodiment of the transmission may optionally include one or more of the embodiments described above, and a drive assembly having an input linked to a crankshaft and an output linked to a countershaft, wherein the crankshaft drives the drive assembly such that the countershaft rotates faster and with less torque than the crankshaft, the driven assembly is positioned around the crankshaft, the input of the driven assembly is linked to a fixed driven sheave and a movable driven sheave, the output of the driven assembly is configured to rotate slower and with more torque than the fixed driven sheave and the movable driven sheave, and the output of the driven assembly is configured to transmit power to propel the bicycle.

[0057] A fifth embodiment of the transmission may include one or more of the embodiments described above, wherein the biasing member is a spring that generates either a force that changes linearly or a force that changes non-linearly in response to displacement.

[0058] A sixth aspect of this specification provides a continuously variable transmission for a bicycle, comprising a housing extending from a first side to a second side, and a crankshaft rotatable about a crankshaft, the crankshaft at least partially located within the housing, and a countershaft rotatable about a countershaft, the countershaft located within the housing, and a fixed drive sheave and a movable drive sheave located around the countershaft, the fixed drive sheave and the movable drive sheave located within the housing, the movable drive sheave located between the fixed drive sheave and the first side of the housing, the fixed drive sheave and the movable drive sheave configured to receive power from the countershaft, and a fixed driven sheave located around the crankshaft The system comprises a belt configured to transmit power from the fixed drive sheave and the movable drive sheave to the fixed drive sheave and the movable drive sheave, wherein the fixed drive sheave and the movable drive sheave are located within a housing, and the movable drive sheave is located between the fixed drive sheave and the second side of the housing, and the speed ratio between the fixed drive sheave and the movable drive sheave is continuously variable, and a position motor located between the movable drive sheave and the first side of the housing is configured to move the movable drive sheave along a counter axis to change the speed ratio between the fixed drive sheave and the movable drive sheave and the fixed drive sheave and the movable drive sheave.

[0059] A transmission in a sixth embodiment may optionally include a biasing member configured to act on a movable driven sheave along the crankshaft, the biasing member positioned between the movable driven sheave and a second side of the housing, the movable driven sheave changing position along the crankshaft to correspond to the speed ratio set by the fixed drive sheave and the movable drive sheave.

[0060] A transmission of the sixth embodiment may include one or more of the embodiments described above, and optionally a fixed collar positioned around a crankshaft, wherein the fixed driven sheave engages with the fixed collar and comprises a movable collar positioned around the fixed collar, and the movable driven sheave engages with the movable collar and comprises a plurality of pins extending from the fixed collar to each slot of the movable collar, and the movable collar and movable driven sheave are configured to transmit power to the fixed collar and move along the crankshaft.

[0061] A transmission of a sixth embodiment may include one or more of the embodiments described above, and optionally, a drive assembly disposed between a second side of the housing and a fixed drive sheave, the drive assembly configured to transmit power from the crankshaft to the countershaft so that the countershaft rotates at a higher speed and with lower torque than the crankshaft, and a driven assembly disposed around the crankshaft between a first side of the housing and a fixed driven sheave, the driven assembly configured to transmit power from the fixed driven sheave and a movable driven sheave to a drive wheel so that the drive wheel rotates at a lower speed and with higher torque than the fixed driven sheave and the movable driven sheave.

[0062] A sixth embodiment of the transmission may include one or more of the embodiments described above, in which, optionally, a drive assembly is located in a first sealed portion of a housing configured to receive a lubricant, and a driven assembly is located in a second sealed portion of a housing configured to receive a lubricant.

[0063] A transmission of the sixth embodiment includes one or more of the embodiments described above, wherein the belt selectively has a V-shaped cross-section, and the inner surfaces of the fixed drive sheave and the movable drive sheave, and the inner surfaces of the fixed driven sheave and the movable driven sheave, are tapered in a manner complementary to the sides of the V-shaped belt.

[0064] The phrases “at least one,” “one or more,” and “and / or” used in this book are non-restrictive (open-ended) expressions that have both conjunctive and disjunctive functions. For example, the expressions “at least one of A, B, and C,” “at least one of A, B, or C,” “one or more of A, B, and C,” and “A, B, and / or C” mean A alone, B alone, C alone, A and B simultaneously, A and C simultaneously, B and C simultaneously, or A, B, and C simultaneously, respectively.

[0065] Unless otherwise specified, all numerical values ​​representing quantities, dimensions, conditions, etc., used in this specification and in the claims shall be understood in all cases to be modified by the term "approximately".

[0066] The "a" or "an" subject used here indicates that there is one or more subjects. Therefore, the terms "a" (or "an"), "one or more," and "at least one" are used interchangeably in this book.

[0067] The terms “include,” “equip,” “have,” and their variations herein encompass the items and their equivalents listed thereafter, as well as any additional items. Thus, “include,” “equip,” “have,” and their variations herein can be used interchangeably. “Engage,” and its variations herein encompass any direct or indirect connection between components.

[0068] As used herein, the term “means” shall be understood to be interpreted as broadly as possible in accordance with 35 U.S. Code § 112(f). Accordingly, any claim containing the term “means” shall encompass all structures, materials, or actions described herein, and all their equivalents. Furthermore, structures, materials, or actions, and their equivalents, shall include all those described in the summary of the invention, the brief description of the drawings, the detailed description, the abstract, and the claims themselves.

[0069] These and other advantages will become apparent from the disclosure of the invention contained herein. The embodiments, objectives, and configurations described above are neither complete nor exhaustive. The summary of the invention is not intended to represent, and should not be construed to represent, the entire scope or scope of this specification. Furthermore, references to “the invention” or its embodiments herein should be understood to mean certain embodiments of the invention / disclosure, and should not necessarily be construed to limit all embodiments to a particular description. The invention is described in detail at various levels in the summary of the invention, the accompanying drawings, and the detailed description, and the inclusion or exclusion of elements, components, etc., in the summary of the invention is not intended to limit the scope of the invention. Further aspects of the invention will become more readily apparent when read in conjunction with the detailed description, in particular with the drawings.

[0070] It should be understood that any feature or aspect described herein, whether or not it derives from the same embodiment, can be combined with any other feature or aspect described herein to form the claimed invention.

[0071] One or more embodiments described herein can be combined with one or more other embodiments described herein. One or more features described herein can be combined with one or more other features described herein. One or more embodiments described herein can be combined with one or more other embodiments described herein. [Brief explanation of the drawing]

[0072] Those skilled in the art will understand that the following description is merely illustrative of the principles of the present invention and can be applied in various ways to provide many different alternative embodiments. This description is intended to illustrate the general principles teaching the invention and is not intended to limit the concepts of the invention disclosed herein.

[0073] The accompanying drawings incorporated herein and constituting part of this specification illustrate embodiments and, together with the general description of the invention and the detailed description of the drawings below, illustrate the principles of the invention. [Figure 1] This is a side view showing a part of a bicycle equipped with a gear shifter according to one embodiment of the present invention. [Figure 2A] This is a side view of the transmission shown in Figure 1, relating to one embodiment of the present invention. [Figure 2B] This is a top cross-sectional view of a transmission along line AA in Figure 2A, relating to one embodiment of the present invention. [Figure 3A] This is a perspective view of the first planetary gear set according to one embodiment of the present invention. [Figure 3B] This is a perspective view of the first planetary gear set of Figure 3A without a carrier, according to one embodiment of the present invention. [Figure 3C] This is a perspective view of a second planetary gear set according to one embodiment of the present invention. [Figure 4A] This is a perspective view showing a part of the transmission in Figure 1 at a high speed ratio according to one embodiment of the present invention. [Figure 4B] This is a partial perspective view of the low-speed ratio of the transmission shown in Figure 1, according to one embodiment of the present invention. [Figure 5] This is a perspective view of a portion of the transmission shown in Figure 1, excluding the belt, movable drive sheave, and fixed driven sheave, according to one embodiment of the present invention. [Figure 6] Figure 1 is a perspective view of the position motor, hub, and countershaft of the transmission according to one embodiment of the present invention. [Figure 7] This is a perspective view of a third planetary gear set according to one embodiment of the present invention. [Figure 8] This is a perspective view of an output gear and drive wheel according to one embodiment of the present invention. [Figure 9] This is a schematic diagram of a controller and other components relating to one embodiment of the present invention. [Figure 10] This is a perspective view of a transmission according to one embodiment of the present invention. [Figure 11]This is a bottom cross-sectional view of a transmission along line BB in Figure 10, relating to one embodiment of the present invention. [Figure 12] Figure 10 is a perspective view of the drive assembly of the transmission according to one embodiment of the present invention. [Figure 13] This is a perspective view of the position motor of the transmission shown in Figure 10, relating to one embodiment of the present invention. [Figure 14] This is a perspective view of the fixed driven sheave of the transmission shown in Figure 10, according to one embodiment of the present invention. [Figure 15] Figure 10 is a perspective view of the drive assembly of the transmission according to one embodiment of the present invention. [Figure 16] This is a perspective view of a transmission according to one embodiment of the present invention. [Figure 17] This is a plan cross-sectional view of a transmission along line CC in Figure 16, according to one embodiment of the present invention. [Figure 18] Figure 16 is a perspective view of the driven assembly of the transmission according to one embodiment of the present invention.

[0074] It should be understood that the drawings are not necessarily to scale and may be modified to various dimensions. In some cases, details that are not necessary for understanding the invention, or details that would make it difficult to understand other details, may be omitted. Of course, it should be understood that the invention is not necessarily limited to the specific embodiments described herein.

[0075] 2 Bicycles 4 Crankshaft 6 pedals 8 drive wheels 10 chains 12 Rear Hub 14 Rear wheels 16-speed transmission 18 Housing 20 Part 1 22 Part 2 24 Crank Axle 26. First Planetary Gear Set 28. Second Planetary Gear Set 30 Fixed drive sheave 32 Movable drive sheave 34. Biasing member 36 belts 38 Countershaft 40 Counter axis 42 Fixed driven sheave 44 Movable driven sheave 46-Position Motor 48. Third Planetary Gear Set 50 First Output Gear 52 Second Output Gear 54 First Carrier 56 Ring Gear 58a, 58b First Planetary Gear 58c, 58d First planetary gear 60 First Solar Gear 62. Second Carrier 64a, 64b Second Planetary Gear 66 Second Solar Gear 68 Drive shaft 70 drive pins 72 drive slots 74 Dependent Slots 76 Driven pin 77 screws 78 Hub 80 Output shaft 82 Eccentric Cam 84 recess 86 Third Solar Gear 88a, 88b Third Planetary Gear 90 Third Ring Gear 92 Input section 94 Controllers 96 batteries 98 Electric motor 100 transmission 102 Housing 104 Crankshaft 106 Part 1 107 1st side 108 Part 2 109 Second side 110 Crank Axle 112 Intermediate shaft 114 Intermediate shaft 116 Countershaft 118 Counter shaft 120 drive wheels 122 Drive Gear Assembly 124 First Gear 126 Second Gear 128 Third Gear 130 Fourth Gear 132 Fixed drive sheave 134 Movable drive sheave 136 Position Motor 140 Hub 142 Output shaft 144 Eccentric Cam 146 belts 148 First driven sieve 150 Movable driven sheave 152 Biasing member 154 Driven Gear Assembly 156 Sun Gear 158 Planetary Gear 160 carriers 162 Ring Gear 164 1st sealed part 166 Second sealed part 168 recess 170 Fixed Colors 172 pins 174 Movable Color 176 slots 177 Slot Axis 178 transmission 180 Housing 182 Crankshaft 184 Crank Axle 186 Countershaft 188 Counter axis 190 drive wheels 192 Drive Gear Assembly 194 Fixed drive sheave 196 Movable drive sheave 198 Biasing member 200 belts 202 Fixed driven sheave 204 Movable driven sheave 206 Position Motor 208 Driven Sprocket Assembly 210 drive sprocket 212 belt 214 Detailed Description of the Driven Sprocket Invention

[0076] The following text provides a detailed description of numerous different embodiments, but it should be understood that the legal scope of the description is defined by the claims text set forth at the end of this specification. The detailed description should be interpreted as illustrative only and does not cover all embodiments, for it is impractical, if not impossible, to cover all embodiments of a transmission. Numerous alternative embodiments can be carried out using current technology or technology developed after the filing date of this patent, and these are also included in the claims. Furthermore, further embodiments can be created using any combination of features shown in the various figures. Thus, embodiments of the claims can be created by combining the dimensions, aspects, and features of one embodiment of a transmission with the dimensions, aspects, and features of another embodiment of a transmission.

[0077] Figure 1 shows a part of a bicycle 2 equipped with a continuously variable transmission 16 of this embodiment. The user operates the pedals 6 to rotate the crankshaft 4 and the drive wheel 8 (sprocket in this embodiment). The rotation of the drive wheel 8 causes the chain 10, which is meshed with the sprocket on the rear hub 12, to rotate, and the rotation of the rear hub 12 drives the rear wheel 14, causing the bicycle 2 to move forward.

[0078] In one embodiment, the bicycle 2 is equipped with multiple sprockets on the rear hub 12 and / or crankshaft 4, and the gear shift system changes the gear ratio between the rear hub 12 and crankshaft 4 by moving the chain 10 between these various sprockets. The derailleur 16 of this specification eliminates the need for multiple sprockets on the rear hub 12 and / or crankshaft 4. However, it will be understood that this embodiment can be used in conjunction with multiple sprockets provided on the rear hub 12 and / or crankshaft together with the gear shift system. Furthermore, it will be understood that this embodiment can be used in conjunction with, for example, an electric motor, controller, and / or battery mounted on an electric bicycle, as well as other components mounted on the bicycle.

[0079] Figure 2A is a side view of the continuously variable transmission 16 described herein. The transmission 16 comprises a crankshaft 4, a drive wheel 8, and other components described herein, and changes the speed ratio of the transmission 16, coordinating the user's force with the movement of the bicycle, whether the bicycle is stationary or moving at a specific speed. In various embodiments, the user can customize the bicycle by selecting, for example, the crankshaft 4, the drive wheel 8, the pedals, or the crank arms that connect the pedals to the crankshaft 4. Thus, the term “transmission” may include embodiments that include these components as well as embodiments that do not. Also, line AA is shown in Figure 2A.

[0080] Figure 2B is a horizontal cross-sectional view of the continuously variable transmission 16 as seen along line AA in Figure 2A. The crankshaft 4 is rotatable around the crank axis 24, and the drive wheel 8 is positioned around the crankshaft 4. In addition, several components that connect the power applied by the user to the crankshaft 4 and the drive wheel 8 transmit power to the rear hub to propel the bicycle forward.

[0081] The transmission 16 comprises a set of drive sheaves 30, 32 that drive a belt 36, and the belt 36 transmits power to a set of driven sheaves 42, 44. The set of driven sheaves 42, 44 continuously changes and defines the speed ratio between the sheave sets, and the system consisting of these sheaves and the belt 36 functions more efficiently at higher rotational speeds. Specifically, the higher the rotational speed, the smaller the force, i.e., the torque, which improves the reliability and lifespan of the components of the transmission 16. Therefore, in some embodiments, the drive assembly has an input part that engages with the crankshaft 4 and an output part that engages with the drive sheaves 30, 32 that rotate faster and with lower torque than the crankshaft. In Figure 2B, the drive assembly (which can also be called the drive gear assembly in this example) comprises a first planetary gear set 26 and a second planetary gear set 28. The input of the first planetary gear set 26 engages with the crankshaft 4, and its output engages with the input of the second planetary gear set 28. The second planetary gear set 28 has an output that engages with a set of drive sheaves 30 and 32.

[0082] In some embodiments, the derailleur 16 is located on the bottom bracket of the bicycle frame, and the crankshaft 4 passes through the derailleur 16. Thus, the drive gear assembly is constrained by its position around the crankshaft 4 and the distance between the crank arms on the crankshaft 4. Furthermore, the drive gear assembly is constrained by the overall form factor of the derailleur 16 and the housing 18, as some parts of the bicycle are connected in a specific arrangement, and some parts maintain a ground clearance distance. Thus, a set of two planetary gear sets 26, 28 achieves an overall gear reduction between approximately 1:12.2 and 1:20.3 to satisfy these constraints. In various embodiments, the gear ratio of each planetary gear set 26, 28 is approximately 1:3.5 to 1:4.5. In some embodiments, the gear ratio of each planetary gear set 26, 28 is approximately 1:4. In some embodiments, each planetary gear set 26, 28 has the same gear ratio, and in other embodiments, each planetary gear set 26, 28 has different gear ratios.

[0083] Although the figure depicts two planetary gear sets 26 and 28, it should be understood that this specification encompasses embodiments of drive gear assemblies with any number of gear sets, gear sets other than planetary gear sets, sprockets, belts, etc. For example, in some embodiments, the drive gear assembly comprises a single planetary gear set or a system of spur gears to give a desired gear ratio. Furthermore, it should be understood that the gear ratios specified above are essentially illustrative. For example, the gear ratio of a single planetary gear set can range from about 1:2 to 1:20.

[0084] Many components of the transmission 16 are located within a housing 18, which may have a first section 20 on a first side and a second section 22 on a second side. The first and second planetary gear sets 26, 28 are located within the first section 20 of the transmission 16 so as to be sealed and at least partially filled with lubricant, thereby facilitating the operation of the first and second planetary gear sets 26, 28 among the other components described herein. The sheaves 30, 32, 42, 44 and the belt 36 are located within the second section 22, which may not be sealed with lubricant, but can be protected from the external environment.

[0085] The output of the drive gear assembly transmits power to a set of drive sheaves 30 and 32. The fixed drive sheave 30 is rotatable around the crankshaft 24 but cannot move along the crankshaft 24. The movable drive sheave 32 is rotatable around the crankshaft 24 and can move along the crankshaft 24 at the same time. A biasing member 34 acts on the movable drive sheave 32, biasing it toward the fixed drive sheave 30. The biasing member 34 can respond linearly or nonlinearly to force, for example, a spring. The variable distance between the drive sheaves 30 and 32 enables different speed ratios by the set of driven sheaves 42 and 44.

[0086] The set of driven sheaves 42, 44 comprises a fixed driven sheave 42 that is rotatable around the counter shaft 40 of the counter shaft 38 but cannot move along the counter shaft 40, and a movable driven sheave 44 that is rotatable around the counter shaft 40 and can move along the counter shaft 40. A position motor 46 controls the position of the movable driven sheave 44 along the counter shaft 40 to establish the speed ratio between the sheave set, and thus the overall speed ratio (similar to a gear ratio) of the transmission 16. In some embodiments, the position motor 46 is a servo motor that rotates the output shaft, but it should be understood that this specification also includes embodiments in which the position motor is other devices such as actuators.

[0087] The movable sheaves 32 and 44 are positioned on the opposite side of the belt 36 to stabilize the belt 36 within the sheaves. Specifically, the movable drive sheave 32 is positioned between the fixed drive sheave 30 and the drive gear assembly, and the fixed driven sheave 42 is positioned between the movable driven sheave 44 and the driven gear assembly. It should be understood that this specification also includes embodiments with modified sheave arrangements.

[0088] The set of driven sheaves 42, 44 powers the countershaft 38, which rotates at a relatively high speed, as do the sheaves 30, 32, 42, 44 and the belt 36, reducing the forces on certain components within the transmission 16. The output of the countershaft 38 works in conjunction with the driven assembly to reduce speed and increase torque, making it more effective to power the drive wheel 8 and ultimately the rear hub 12 of the rear wheel to propel the bicycle. In this embodiment, the driven assembly (which in this example may be called the driven gear assembly) is a third planetary gear set 48. The output of the third planetary gear set 48 engages with a first output gear 50 that rotates around the countershaft 40. The first output gear 50 engages with a second output gear 52 that rotates around the crankshaft 24. This second output gear 52 powers the drive wheel 8. In the illustrated embodiment, the output gears 50, 52 have gear ratios that further reduce speed and increase torque.

[0089] Figures 3A and 3B show the first planetary gear set 26. In this embodiment, the crankshaft 4 is connected to the carrier 54 of the first planetary gear set 26. The carrier 54 drives four planetary gears 58a-58d arranged within a ring gear 56. In other embodiments included herein, the number of planetary gears 58a-58d may be greater or less. In this embodiment, the ring gear 56 is fixed to the housing and does not rotate. The four planetary gears 58a-58d rotate (i.e., drive) the first sun gear 60, which is the output of the first planetary gear set 26. In this embodiment, the gear ratio is 1:4, but it will be understood that this specification encompasses any gear ratio. Furthermore, it will be understood that this disclosure encompasses other arrangements of gears or other components other than the planetary gear unit to increase the rotational speed of the output.

[0090] Figure 3C shows the second planetary gear set 28. The same ring gear 56 of the first planetary gear set 26 interlocks with the components of the second planetary gear set 28. Thus, the terms “first planetary gear set” and “second planetary gear set” may, in various embodiments, include the same ring gear 56, different components of the same ring gear 56, or different ring gears 56. The first sun gear (60 in Figure 3B) is connected to the second carrier 62 of the second planetary gear set 28. The second carrier 62 drives two planetary gears 64a, 64b, and these planetary gears 64a, 64b drive the second sun gear 66, which serves as the output of the second planetary gear set 28. The second planetary gear set 28 and other planetary gear sets described herein may comprise any number of planetary gears, e.g., two, four, or more.

[0091] Figures 4A and 4B show the components of the transmission, with Figure 4A showing the high-speed ratio and Figure 4B showing the low-speed ratio. In Figure 4A, the position motor 46 pulls the movable driven sheave 44 towards the fixed driven sheave 42, and this relative positional relationship between the driven sheaves 42 and 44 presses the belt 36, moving it away from the rotation axis of the driven sheaves 42 and 44. As a result, the belt 36 contacts the inner surfaces of the driven sheaves 42 and 44 at a position further from the rotation axis than in the case of the low-speed ratio shown in Figure 4B, and at a position further from the rotation axis than the belt 36 inside the drive sheaves 30 and 32.

[0092] When belt 36 is positioned in the driven sheaves 42, 44, belt 36 is pulled inward in the drive sheaves 30, 32, moving closer to the axis of rotation of the drive sheaves 30, 32. The inward pulling force on belt 36 exceeds the force from the biasing member 34 acting on the movable drive sheave 32, thereby moving the movable drive sheave 32 further away from the fixed drive sheave 30 (along the crankshaft). As a result, belt 36 contacts the inner surface of the drive sheaves 30, 32 at a position closer to the axis of rotation of the drive sheaves 30, 32 than in the case of the low speed ratio shown in Figure 4B, and also closer to the axis of rotation than belt 36 in the driven sheaves 42, 44. The speed ratio in Figure 4A is a higher speed ratio that provides higher torque and lower rotational speed, which is suitable for stationary or low-speed vehicles.

[0093] In Figure 4B, the position motor 46 moves the movable driven sheave 44 further away from the fixed driven sheave 42, and this relative positioning between the driven sheaves 42 and 44 allows the belt 36 to move closer to the rotation axis of the driven sheaves 42 and 44. As a result, the belt 36 contacts the inner surfaces of the driven sheaves 42 and 44 at a position even closer to the rotation axis of the driven sheaves 42 and 44.

[0094] Depending on the relative positions of the driven sheaves 42 and 44, the force from the biasing member acting on the movable drive sheave 32 brings the movable drive sheave 32 closer to the fixed drive sheave 30 and absorbs the slack in the belt 36 that is permitted by the relative positions of the driven sheaves 42 and 44. As a result, the belt 36 contacts the inner surfaces of the drive sheaves 30 and 32 at a position further away from the axis of rotation of the drive sheaves 30 and 32. From this perspective, the force, which may be linear or nonlinear in response to the biasing member, acts in coordination with the tensile force from the belt 36 caused by the relative positions of the driven sheaves 42 and 44. The speed ratio in Figure 4B is a lower speed ratio that provides lower torque and a faster rotational speed, making it more suitable for a moving vehicle to achieve higher speeds. As shown in the figure, the belt 36 may have a V-shaped cross-section in which the inner and outer surfaces of the belt 36 are approximately parallel to each other, the sides of the belt 36 are tapered, and the shape complements the angled inner surfaces of the sheaves 30, 32, 42, and 44.

[0095] Figure 5 is a perspective view of the transmission components with the belt, a portion of the movable drive sheave 32, and the fixed driven sheave removed. Viewed from the drive side of the transmission, the drive shaft 68 is positioned around the crankshaft 4 and connected to the output of the drive gear assembly (in this embodiment, the second sun gear in Figure 3C). It will be understood that in various embodiments, the drive shaft 68 and the second sun gear may be a single component. The drive shaft 68 receives power from the drive gear assembly and transmits power to the drive sheaves 30, 32. In this embodiment, the drive shaft 68 is directly connected to the fixed drive sheave 30, and the drive shaft 68 is connected to the movable drive sheave 32 by a pin-slot mechanism. Multiple pins 70 extend outward from the drive shaft 68 and are each positioned in slots 72 provided in a portion of the movable drive sheave 32. The portion of the movable drive sheave 32 having slots 72 may be a cylindrical portion and / or a portion positioned around the crankshaft. In some embodiments, the portion of the movable drive sheave 32 having slots 72 is the portion that does not come into contact with the belt 36. Each slot 72 extends along a line that is not parallel to the crankshaft. The angle and orientation of the slots 72 balance several functions, including efficient power transmission from the drive shaft 68 to the movable drive sheave 32, reduction of the force required to move the movable drive sheave 32 along the crankshaft, and prevention of belt slippage against the sheave when the transmission changes continuously between speed ratios.

[0096] Similarly, on the driven side of the transmission, pins 76 extend from the countershaft 38 and are positioned in slots 74 provided in a portion of the movable driven sheave 44. The portion of the movable driven sheave 44 with slots 74 can be a cylindrical portion and / or a portion positioned around the countershaft 38. In some embodiments, the portion of the movable driven sheave 44 with slots 74 is a portion that does not contact the belt 36. Thus, the movable driven sheave 44, together with the fixed driven sheave 42, transmits power from the belt to the countershaft 38. Furthermore, each slot 74 extends along a line that is not parallel to the counter axis. The angle and orientation of the slots 74 balance several functions, including the function of effectively transmitting power from the movable driven sheave 44 to the countershaft 38, the function of reducing the force required to move the movable driven sheave 44 along the counter axis, and the function of preventing the belt from slipping against the sheave when the transmission changes continuously between speed ratios.

[0097] The position motor 46 engages with the hub 78, moving the movable driven sheave 44 along the counter shaft to set the transmission speed ratio. The hub 78 is offset along the counter shaft from the movable driven sheave 44 and is connected to the movable driven sheave 44 by several bolts 77. This connection provides space for connecting a fixed driven sheave (42 in Figures 4A and 4B) to the counter shaft 38. Although several bolts 77 are depicted, it should be understood that this specification also encompasses other embodiments of the connection between the hub 78 and the movable driven sheave 44, such as pins or other connection mechanisms.

[0098] Figure 6 is a plan view of the position motor 46, hub 78, and movable driven sheave 44. In this embodiment, the position motor 46 is a servo motor having an output shaft 80. The position motor 46 can rotate the output shaft 80 clockwise or counterclockwise around its longitudinal axis. An eccentric cam 82 is connected to the output shaft 80, and the rotation of the output shaft 80 also rotates the eccentric cam 82. In one embodiment, the output shaft 80 has a circular cross-section with a planar section, and the eccentric cam 82 has a hole of a similar shape, and the output shaft 80 fits into the eccentric cam 82 like a key fitting into a keyhole. The key connection can be of different shapes, such as a square, triangle, hexagon, or a convex circle. The eccentric cam 82 is generally cylindrical, and the central axis of the cylinder is offset from the axis of the output shaft 80. In other words, the output shaft 80 does not pass through the center point (and central axis) of the eccentric cam 82 and / or is not concentric with the center point of the eccentric cam 82. Therefore, when the output shaft 80 rotates, the eccentric cam 82 rotates, and the central axis or mass of the eccentric cam 82 moves in a direction parallel to the counter shaft 40, that is, from side to side as shown in Figure 6.

[0099] The eccentric cam 82 is positioned in a recess 84 of the hub 78, and the movement of the hub 78 is restricted to movement along the counter shaft 40. Thus, the movement of the eccentric cam 82 parallel to the counter shaft 40 is transmitted to the hub 78, and the hub 78 moves along the counter shaft 40. As the hub 78 moves along the counter shaft 40, the movable driven sheave (44 in Figures 4A and 4B) moves along the counter shaft 40 in response to the rotation of the output shaft 80 of the position motor 46, since the hub 78 is connected to the movable driven sheave (44 in Figures 4A and 4B). The position motor 46 can rotate the output shaft 80 with specific characteristics so that the movable driven sheave (44 in Figures 4A and 4B) can set or change the speed ratio with specific characteristics. The position motor 46 can rotate the output shaft 80 with a predetermined angular velocity, angular momentum, and / or angular acceleration. Furthermore, the position motor 46 can accommodate shifts or constantly changing speed ratios, rather than moving between discrete speed ratios, by rotating the output shaft 80.

[0100] In the diagram, the position motor 46 controls the relative position of the driven sheave, but in some embodiments, the position motor 46 controls the relative position of the drive wheel, and the driven sheave is automatically adjusted to a speed ratio set by the position motor 46 and the drive wheel.

[0101] Figure 7 shows a driven gear assembly, which in this embodiment is a third planetary gear set 48. The countershaft 38 is connected to the input of the third planetary gear set 48, which in this embodiment is a third sun gear 86. Although the countershaft 38 and the third sun gear 86 are shown as separate parts, it will be understood that this specification also encompasses further embodiments, including embodiments in which the countershaft 38 and the third sun gear 86 are a single part.

[0102] The power transmitted to the third sun gear 86 rotates the two planetary gears 88a and 88b, and then rotates the ring gear 90. As a result, the ring gear 90 rotates slower than the countershaft 38 and the third sun gear 86, but with greater torque. The ring gear 90 is connected to the first output gear 50, whose teeth extend to surround the outer surface of the first output gear 50. In some embodiments, the ring gear 90 and the first output gear 50 are separate components, and in some embodiments, the ring gear 90 and the first output gear 50 are a single component, and the ring gear 90 may have teeth extending to surround the inner and outer surfaces.

[0103] Figure 8 shows the first output gear 50 connected to the second output gear 52, which meshes with the drive wheel 8. Power is transmitted from the first output gear 50 to the second output gear 52, and these gears 50, 52 can have various gear ratios, either maintaining the same torque and speed, increasing torque while decreasing speed, or decreasing torque while increasing speed. The second output gear 52 then transmits power to the drive wheel 8. In the illustrated embodiment, the drive wheel 8 is fixed to a portion of the second output gear 52 and secured with a clip. However, it should be understood that this specification also includes embodiments in which the drive wheel 8 is fixed to a portion of the second output gear 52 in a different way, and embodiments in which the drive wheel 8 and the second output gear 52 are a single part. The second output gear 52 and the drive wheel 8 are arranged around the crankshaft and rotatable around the crankshaft, similar to the typical arrangement of the drive wheel 8 in a conventional bicycle. The drive wheel 8 meshes with the chain to drive the rear hub of the bicycle, propelling the bicycle. Alternatively, instead of gears 50 and 52, power can be transmitted by a belt, such as a timing belt. In addition, or alternatively, instead of a drive wheel and chain, a belt system can be used to drive the rear hub and / or the rear wheel of the bicycle.

[0104] Figure 9 shows a schematic diagram of the controller 94 and other components that communicate with each other for the operation of the transmission. The input unit 92 transmits an input signal to the controller 94, where the input signal is analyzed, and according to the analysis result, the controller 94 allows power supply from the battery 96 to the position motor 46 and determines the speed ratio of the transmission.

[0105] The input unit 92 can be a variety of devices, and some embodiments of this specification may have multiple input units 92. In one embodiment, the input unit 92 is a shift lever, such as a gear shifter on a bicycle. Thus, in various embodiments, the user can select a speed ratio by moving a dial or paddle provided on the input shifter 92. The physical movement of the dial or paddle is detected by a sensor on the input shifter 92, and the sensor transmits an input signal to the controller 94. In some embodiments, the user selects from a finite number of speed ratios to maintain a system familiar to users of conventional bicycles. In various embodiments, the user selects from a possible range of continuously variable speed ratios. The input signal or other signals can be transmitted via a wired or wireless connection.

[0106] The controller 94 changes the amount of power supplied from the battery 96 to the position motor 46 based on the input signal. Furthermore, the controller 94 can simultaneously send output signals to the position motor 46 to instruct its operation, such as the direction of rotation of the output shaft, the rotational speed of the output shaft, and the acceleration, based on the input signal.

[0107] Another input unit 92 is a torque sensor connected to a component connected to the drive wheel, such as the crankshaft and the drive wheel, or a second output gear. When the user applies force to the pedals and crankshaft, the crankshaft generates torque on the drive wheel. In some situations, when coasting downhill, the user applies low torque or no torque at all. On the other hand, in other situations, when climbing uphill, the user applies greater torque and puts in considerable effort. The torque sensor transmits an input signal to the controller 94, which decides whether to take further action based on the input signal. Further actions include, among other actions described herein, changing the amount of power supplied from the battery 96 to the position motor 46, for example, transmitting an output signal to the position motor 46 to reduce the speed ratio to assist the user's considerable effort. The torque sensor (input unit) 92 can also transmit information regarding the rotational speed of the crankshaft and / or the drive wheel. In other embodiments, a separate cadence sensor or speed sensor can be another input unit 92 to the controller 94. The input unit 92 can be any sensor that detects the characteristics of the transmission, the environment around the transmission, or user input.

[0108] Furthermore, in various embodiments, the gearbox operates in conjunction with other components, such as an electric motor 98, as in the case of an electric bicycle, or e-bike. In an e-bike, the electric motor is used to assist the user in various situations, such as pedaling uphill or starting from a standstill. For the same purpose of assisting the user's effort, this specification includes embodiments in which the gearbox described herein is combined with an electric motor 98.

[0109] In some embodiments, user input and / or input from sensors such as torque sensors are transmitted to the controller 94 in the form of input signals. Based on these input signals, the controller 94 gives instructions to the gear position motor 46 and / or electric motor 98 to assist the user's attempt. In some embodiments, these include changing the gear speed ratio set by the position motor 46 and generating torque in the electric motor to assist in propelling the vehicle. In various embodiments, the bicycle's battery 96 can be charged by a wheel-mounted generator and / or regenerative brake.

[0110] Figure 10 is a perspective view of a gear shifter 100 used in vehicles such as bicycles. Most of the components of the gear shifter 100 are housed in a protective housing 102 to prevent contamination of the components by mud and other elements. A crankshaft 104 extends from the housing 102, and the user rotates the crankshaft 104 by turning the pedals and crank arms, thereby inputting mechanical power to the gear shifter 100. The bottom bracket line is also shown in Figure 10.

[0111] Figure 11 is a bottom cross-sectional view of the transmission 100 along the BB line in Figure 10. The housing 102 comprises a first part 106 on the first side 107 of the transmission 100, which is connected to a second part 108 on the second side 109 of the transmission 100. The terms “first side” and “second side” are relative and can be used in reverse or replaced with other relative terms.

[0112] The crankshaft 104 rotates around the crankshaft 110, providing mechanical power input to the transmission 100. As the crankshaft 104 rotates, power is first transmitted through the drive assembly 122 (referred to here as the drive gear assembly 122) to increase the speed of the belt 146 in the transmission 100 and reduce the torque. The increased speed allows for faster and more responsive changes in the speed ratio, while the reduced torque reduces wear on the belt 146 and surrounding components. The drive gear assembly 122 comprises a first gear 124 coupled to the crankshaft 104 and positioned around it. The teeth on the outer surface of the first gear 124 mesh with the teeth on the outer surface of a second gear 126, which is coupled to the intermediate shaft 112 and positioned around it. The intermediate shaft 112 is rotatable around the intermediate shaft 114. A third gear 128 is then coupled to the intermediate shaft 112 and positioned around it. The teeth on the outer surface of the third gear 128 are connected to the countershaft 116 and mesh with the teeth on the outer surface of the fourth gear 130, which is positioned around it. The countershaft 116 is rotatable around the counter shaft 118.

[0113] In this drive gear assembly 122, the second gear 126 has fewer teeth than the first gear 124, and the fourth gear 130 has fewer teeth than the third gear 128, with the second gear 126 and third gear 128 rotating together with the intermediate shaft 112. Therefore, the drive gear assembly 122 rotates the countershaft 116 at a higher speed and with lower torque than the crankshaft 104. If the overall gear ratio of the drive gear assembly 122 is too low, the torque reduction will be insufficient, resulting in greater stress, wear, and breakage on the sheaves and belts. If the overall gear ratio is too high, the components of the transmission 100 may be exposed to excessive speed, reducing the efficiency of components such as bearings and other moving parts. Therefore, in some embodiments, the overall gear ratio of the drive gear assembly 122 is between approximately 1:3.8 and 1:14.5. In various embodiments, the overall gear ratio of the drive gear assembly 122 is approximately 1:9.

[0114] It will be understood that other drive assemblies 122 can be used instead of the drive gear assembly 122 in Figure 11. For example, the gear train of a planetary gear set (26, 28 in Figure 2B) can be used as the drive assembly 122 in Figure 11. The drive assembly 122 can be located in a sealed portion of the housing 102, which contains a lubricant. The terms drive assembly or driven assembly can include not only gear assemblies but also other assemblies that change the speed and torque of rotating parts without having gears.

[0115] Next, the countershaft 116 transmits power to the fixed drive sheave 132 and the movable drive sheave 134, causing the belt 146 to rotate. The fixed drive sheave 132 rotates around the countershaft 118 but does not move along the countershaft 118, while the movable drive sheave 134 rotates around the countershaft 118 and is movable along the countershaft 118. The position of the movable drive sheave 134 along the countershaft 118 is set by the position motor 136, and the position of the movable drive sheave 134 along the countershaft 118 sets the speed ratio of the transmission 100. When the distance between the drive sheaves 132 and 134 is relatively large, the belt 146 is positioned relatively low within the drive sheaves 132 and 134, and the final output of the transmission 100 is faster and has lower torque. Conversely, if the distance between the drive sheaves 132 and 134 is relatively small, the belt 146 is positioned relatively high within the drive sheaves 132 and 134, resulting in a relatively low speed output from the transmission 100 and a high torque.

[0116] The position motor 136 sets the position of the movable drive sheave 134 along the counter shaft 118 by rotating the output shaft 142, which is located on the eccentric cam 144. Meanwhile, the eccentric cam 144 is located in a recess of the hub 140. As will be shown in more detail with reference to Figure 13, the eccentric cam 144 and the hub 140 convert the rotational motion of the output shaft 142 into the linear motion of the movable drive sheave 134 along the counter shaft 118.

[0117] At the other end of the belt 146 are a movable driven sheave 150 and a fixed driven sheave 148, which are positioned around the crankshaft 104 and receive power from the belt 146. A biasing member 152 exerts force on the movable driven sheave 150 in a linear or nonlinear response, thereby allowing the movable driven sheave 150 to move along the crankshaft 110 in accordance with the movement of the belt 146, as required by the drive sheaves 132, 134 and the position motor 136. The driven sheaves 148, 150 (sometimes referred to as the driven gear assembly 154 in this example) transmit power to the driven assembly 154, amplifying the torque to the drive wheel 120 to reduce its speed.

[0118] To accommodate the setting of the speed ratio and the vertical movement of the belt 146 in the sheaves 132, 134, 148, and 150, the movable drive sheave 134 and the movable driven sheave 150 are positioned on opposite sides of the belt 146. In other words, the movable drive sheave 134 is positioned between the first side of the housing 102 and the fixed drive sheave 132, and the movable driven sheave 150 is positioned between the second side of the housing 102 and the fixed driven sheave 148. This arrangement ensures the stability of the belt 146 even when the speed ratio changes.

[0119] In this embodiment, the driven gear assembly 154 comprises a sun gear 156 that receives power from driven sheaves 148, 150, a plurality of planetary gears 158 that receive power from the sun gear 156, a fixed ring gear 162 inside which the planetary gears 158 rotate, and a carrier 160 that connects the planetary gears 158. The carrier 160 transmits power from the planetary gears 158 to the drive wheel 120. Overall, the driven gear assembly 154 transmits power to reduce the speed of the drive wheel 120 and increase the torque. In some embodiments, the overall gear ratio of the driven gear assembly 154 is between approximately 3:1 and 4.5:1. In various embodiments, the overall gear ratio of the driven gear assembly 154 is between 3.8:1 and 4:1. The driven assembly 154 can be placed in a sealed section of the housing 102 containing a lubricant. As previously stated, different driven assemblies can be substituted for each other. Furthermore, the driven assembly is optional, and in some embodiments herein, the driven assembly is not included. In that case, the driven sheaves 148, 150 power the output of the transmission 100, which rotates at the same speed and torque as the driven sheaves 148, 150.

[0120] Figure 12 is a perspective view of the drive gear assembly 122 of Figure 11. The first gear 124 transmits power from the crankshaft 104 to the second gear 126 and the intermediate shaft 112. The intermediate shaft 112 and the third gear 128 then transmit power to the fourth gear 130 and the countershaft 116. As a result, the countershaft 116 rotates faster and with lower torque than the crankshaft 104.

[0121] Figure 13 is a perspective view of the position motor 136 and drive sheaves 132 and 134. The output shaft 142 of the position motor 136 is located within the eccentric cam 144. In other words, the axis of rotation of the output shaft 142 is offset from the center of the eccentric cam 144. When the position motor 136 receives input and rotates the output shaft 142 and the eccentric cam 144, the eccentric cam 144 also moves along the counter axis 118 of the counter shaft 116. The eccentric cam 144 is located within a recess 168 of the hub 140, and its movement is restricted to the direction along the counter axis 118. Therefore, as the eccentric cam 144 moves along the counter axis 118, the hub 140 also moves along the counter axis 118, and the movable drive sheave 134 also moves along the counter axis 118 to set the speed ratio of the transmission. The position motor 136 can receive input from various components as described in Figure 9, and rotate the output shaft 142 to different rotational positions at different speeds, accelerations, etc.

[0122] The fixed drive sheave 132 can be directly connected to the countershaft 116 to receive power from the countershaft 116. The countershaft 116 may also have pins extending outward and into slots in the movable drive sheave 134, as shown in Figure 5 with the countershaft (38) and movable driven sheave (44). Each slot extends along a line not parallel to the counter shaft 118. The angle and orientation of the slots balance several functions, including efficient power transmission from the countershaft 116 to the movable drive sheave 134, reduction of the force required to move the movable drive sheave 134 along the counter shaft 118, and prevention of belt-sheave slippage when the transmission continuously changes between speed ratios. Furthermore, because the position motor 136 is positioned adjacent to the movable drive sheave 134, the complexity of the components that convert the movement of the output shaft 142 to the movable drive sheave 134 is reduced.

[0123] Figure 14 is a perspective view of a fixed driven sheave 148 rotatable around a crankshaft 104. A movable driven sheave (150 in Figure 11) is not shown here, but a movable driven sheave is connected to a movable collar 174 having one or more slots 176. The movable driven sheave and movable collar 174 may be a single part, or the whole may be referred to as the movable driven sheave. Each slot 176 has an axis 177 that is not parallel to the crankshaft 110. The fixed driven sheave 148 is connected to a fixed collar 170 having one or more pins 172 that extend outward into the corresponding slots 176. The fixed driven sheave 148 and fixed collar 170 may be a single part, or the whole may be referred to as the fixed driven sheave 148. In this embodiment, the multiple slots 176 and multiple pins 172 are arranged at equal intervals around the crankshaft 110. However, it will be understood that the spacing may be uneven, and / or the number of slots 176 and pins 172 may be any number.

[0124] The angle and orientation of slot 176 balance several functions, including efficient power transmission from the drive sheave to the driven assembly, reduction of the force required to move the movable drive sheave along the crankshaft 110, and prevention of belt and sheave slippage when the transmission changes continuously between speed ratios. Specifically, the power received by the drive sheave is transmitted to collars 170 and 174, and the fixed collar 170 transmits power to the sun gear (156 in Figure 15) of the driven assembly described herein.

[0125] The angle between the shaft 177 of slot 176 and the crankshaft 110 can range from about 5 to 50 degrees in some embodiments. In various embodiments, this angle is about 20 degrees. The angle between the shaft of the slot of the movable drive sheave 134 and the countershaft 118 can range from about 5 to 50 degrees in some embodiments. In various embodiments, this angle is about 20 degrees. To ensure compliance with the description requirements of this specification, U.S. Patent Application No. 18 / 126,653 and U.S. Patent Application No. 13 / 328,630 are incorporated herein by reference in their entirety, respectively.

[0126] Figure 15 is a perspective view of the driven gear assembly 154 arranged around the crankshaft 104. The sun gear 156 receives power from the driven sheaves, particularly the fixed collar (170 in Figure 14). The sun gear 156 then drives four planetary gears 158 to a fixed ring gear 162. The carrier 160 connects the planetary gears 158 and transmits power to the drive wheel (120 in Figure 11). The driven gear assembly 154 transmits power to the drive wheel so that the drive wheel rotates with greater torque and at a lower speed than the driven sheaves. The drive wheel then transmits power to the rear hub and rear wheel in the case of a bicycle.

[0127] Figure 16 is a perspective view of a transmission 178 with housing 180, which transmits power to a vehicle such as a bicycle. Figure 17 is a cross-sectional view of the transmission 178 of Figure 16 along line CC. The crankshaft 182 is rotatable around crankshaft 184, and the crankshaft 182 rotates a drive assembly 192, which in this example can be called a drive gear assembly 192. Specifically, the drive gear assembly 192 is a gear train of a planetary gear set, similar to the transmission in Figure 2B. The output of the drive gear assembly 192 rotates a fixed drive sheave 194 and a movable drive sheave 196, which is passively biased by a biasing member 198, in a linear or nonlinear response. The drive sheaves 194 and 196 rotate a belt 200, which in turn rotates a fixed driven sheave 202 and a movable driven sheave 204. The position motor 206 controls the position of the movable driven sheave 204, thereby setting the speed ratio of the transmission. The driven sheaves 202 and 204 rotate the countershaft 186 around the counter shaft 188. The countershaft 186 rotates the driven assembly 208 (which in this example could be called the driven sprocket assembly 208), which transmits power to the drive wheel 190, and further to, for example, the rear hub and rear wheel of a bicycle.

[0128] Figure 18 is a perspective view of the driven sprocket assembly 208 of the transmission 178 shown in Figure 16. The driven sprocket assembly 208 comprises a drive sprocket 210 positioned around the countershaft 186, a driven sprocket 214 positioned around the crankshaft 182, and a synchronous belt 212 connecting the sprockets 210 and 214. Thus, the countershaft 186 rotates the drive sprocket 210, and the drive sprocket 210 rotates the belt 212, the driven sprocket 214, and the drive wheel 190. Because the drive sprocket 210 has fewer teeth than the driven sprocket 214, the drive wheel 190 rotates at a lower speed and with higher torque than the countershaft 186. In this embodiment, the use of sprockets 210, 214, and the belt 212 eliminates the need for a sealed housing containing lubricant, unlike drive or driven assemblies where gears mesh with gears.

[0129] It will be generally understood that various components described herein can be substituted for other embodiments described herein without departing from the scope of the invention. For example, the driven assembly 208 shown in Figure 18 can be used in the transmission shown in Figure 1 or Figure 10.

[0130] While various embodiments of this specification have been described in detail, it will be apparent to those skilled in the art that modifications and changes to these embodiments can be conceived. However, it should be clearly understood that such modifications and changes will remain within the scope and spirit of the claims. Furthermore, the inventions described herein can also be embodied in other ways and carried out in various manner. It should be understood that the expressions and terms used herein are for illustrative purposes only and should not be construed as limiting.

Claims

1. A crankshaft that can rotate around the crank axis, A counter shaft that can rotate around the counter axis, The drive assembly comprises an input section that engages with the crankshaft and an output section that engages with the countershaft, wherein the crankshaft drives the drive assembly, and the drive assembly drives the countershaft, causing the countershaft to rotate at a higher speed and with lower torque than the crankshaft. A drive sheave set arranged around the counter shaft and engaged with the counter shaft, A driven sheave set arranged around the crankshaft, The system comprises a belt configured to connect the drive sheave set and the driven sheave set, and to transmit power from the drive sheave set to the driven sheave set, wherein the speed ratio between the drive sheave set and the driven sheave set is continuously variable. The system comprises a driven assembly positioned around the crankshaft, wherein the input of the driven assembly engages with the driven sheave set, the output of the driven assembly is configured to rotate at a lower speed and with higher torque than the driven sheave set, and the output of the driven assembly is configured to transmit power to propel the bicycle. A continuously variable transmission for bicycles characterized by the following features.

2. Equipped with a position motor, The aforementioned drive sheave set, Fixed sheave and, The system includes a movable sheave that engages with the position motor, The position motor is configured to move the movable sheave along the counter axis to change the speed ratio between the drive sheave set and the driven sheave set. The continuously variable transmission according to feature 1.

3. Further comprising a biasing member, The aforementioned driven sheave set, Fixed sheave and, Equipped with a movable sheave, The biasing member is configured to act on the movable sheave along the crankshaft, and the movable sheave is configured to change position along the crankshaft, corresponding to the speed ratio set by the drive sheave set. The continuously variable transmission according to feature 1.

4. The aforementioned drive assembly The drive assembly comprises a first gear arranged around the crankshaft and being an input to the drive assembly, and a second gear arranged around the intermediate shaft and engaging with the intermediate shaft, wherein the crankshaft drives the first gear, and the first gear drives the second gear, so that the intermediate shaft rotates at a higher speed and with lower torque than the crankshaft. Furthermore, the system includes a third gear positioned around the intermediate shaft and engaging with it, and a fourth gear positioned around the countershaft and being the output of the drive assembly, wherein the intermediate shaft drives the third gear, and the third gear drives the fourth gear, so that the countershaft rotates faster and with lower torque than the intermediate shaft. The continuously variable transmission according to feature 1.

5. The continuously variable transmission according to claim 4, characterized in that the gear ratio between the input and output of the drive assembly is between approximately 1:3.8 and 1:14.

5.

6. The aforementioned driven assembly, The continuously variable transmission according to claim 1, comprising a planetary gear set having a ring gear, a plurality of planetary gears, a carrier connecting the plurality of planetary gears, and a sun gear, wherein the sun gear is the input to the driven assembly, and the sun gear is configured to drive the plurality of planetary gears relative to the ring gear such that the carrier rotates slower than the sun gear and with greater torque, and the carrier is the output to the drive assembly.

7. The aforementioned driven assembly, The first sprocket is the input to the driven assembly, and the second sprocket is the output to the driven assembly. The system includes a belt connecting the first sprocket and the second sprocket. The continuously variable transmission according to feature 1.

8. A crankshaft that can rotate around the crank axis, A counter shaft that can rotate around the counter axis, The system comprises a fixed drive sheave and a movable drive sheave arranged around the counter shaft, the fixed drive sheave and the movable drive sheave being configured to receive power from the counter shaft, A fixed driven sheave and a movable driven sheave are arranged around the crankshaft, The system comprises a fixed drive sheave and a movable drive sheave, and a belt connecting the fixed driven sheave and the movable driven sheave, wherein the belt is configured to transmit power from the fixed drive sheave and the movable drive sheave to the fixed driven sheave and the movable driven sheave, and the speed ratio between the fixed drive sheave and the movable drive sheave and the fixed driven sheave and the movable driven sheave is continuously variable. The system includes a biasing member configured to act on the movable driven sheave along the crankshaft, wherein the movable driven sheave changes its position along the crankshaft to correspond to the speed ratio set by the fixed drive sheave and the movable drive sheave. The system includes a position motor that engages with the movable drive sheave, and the position motor is configured to move the movable drive sheave along the counter axis to change the speed ratio between the fixed drive sheave and the movable drive sheave, and between the fixed driven sheave and the movable driven sheave. A continuously variable speed (CVT) system for bicycles characterized by the following features.

9. The continuously variable speed system according to claim 8, characterized in that the position motor is a servo motor having an output shaft, and the movable drive sheave moves along the counter shaft due to the rotation of the output shaft.

10. An eccentric cam connected to the output shaft of the servo motor, The continuously variable transmission system according to claim 9, further comprising a hub configured to move along the counter axis, wherein the eccentric cam extends into a recess of the hub, the rotation of the output shaft causes the eccentric cam to rotate, the hub moves the movable drive sheave along the counter axis, and changes the speed ratio between the fixed drive sheave and the movable drive sheave and the fixed driven sheave and the movable driven sheave.

11. A controller that communicates with the aforementioned position motor, The system further comprises a shifter that communicates with the controller, the shifter being configured to transmit an input signal to the controller, and the controller being configured to cause the position motor to move the movable drive sheave along the counter axis to change the speed ratio between the fixed drive sheave and the movable drive sheave and the fixed driven sheave and the movable driven sheave. The continuously variable transmission system according to claim 8, characterized in that it is as described above.

12. Furthermore, a controller that communicates with the position motor, The continuously variable transmission system according to claim 8, further comprising a torque sensor operably engaged with the crankshaft and communicating with the controller, wherein the torque sensor is configured to transmit an input signal to the controller, and the controller is configured to cause the position motor to move the movable drive sheave along the counter shaft to change the speed ratio between the fixed drive sheave and the movable drive sheave and the fixed driven sheave and the movable driven sheave.

13. A drive assembly having an input that engages with the crankshaft and an output that engages with the countershaft, the crankshaft drives the drive assembly, the drive assembly drives the countershaft, and the drive assembly causes the countershaft to rotate at a higher speed and with lower torque than the crankshaft. The continuously variable transmission system according to claim 8, comprising a driven assembly disposed around the crankshaft, wherein the input of the driven assembly engages with the fixed driven sheave and the movable driven sheave, the output of the driven assembly is configured to rotate at a lower speed and with higher torque than the fixed driven sheave and the movable driven sheave, and the output of the driven assembly is configured to transmit power to propel the bicycle.

14. The continuously variable speed system according to claim 8, characterized in that the biasing member is a spring that generates either a force that changes linearly or a force that changes non-linearly in accordance with the displacement.

15. A housing extending from the first side to the second side, It comprises a crankshaft rotatable around a crank axis, the crankshaft being at least partially located within the housing, The device includes a counter shaft that is rotatable around the counter axis, and the counter shaft is located within the housing. The system comprises a fixed drive sheave and a movable drive sheave arranged around the counter shaft, the fixed drive sheave and the movable drive sheave being located within the housing, the movable drive sheave being located between the fixed drive sheave and the first side of the housing, and the fixed drive sheave and the movable drive sheave being configured to receive power from the counter shaft. The system comprises a fixed driven sheave and a movable driven sheave arranged around the crankshaft, the fixed driven sheave and the movable driven sheave being located within the housing, and the movable driven sheave being located between the fixed driven sheave and the second side of the housing. The belt is configured to transmit power from the fixed drive sheave and the movable drive sheave to the fixed driven sheave and the movable driven sheave, and the speed ratio between the fixed drive sheave and the movable drive sheave and the fixed driven sheave and the movable driven sheave is continuously variable. The system includes a position motor positioned between the movable drive sheave and the first side of the housing, wherein the position motor is configured to move the movable drive sheave along the counter axis to change the speed ratio between the fixed drive sheave and the movable drive sheave, and between the fixed driven sheave and the movable driven sheave. A continuously variable transmission for bicycles characterized by the following features.

16. The continuously variable transmission according to claim 15, further comprising a biasing member configured to act on the movable driven sheave along the crankshaft, wherein the biasing member is positioned between the movable driven sheave and the second side of the housing, and the movable driven sheave changes position along the crankshaft to correspond to the speed ratio set by the fixed drive sheave and the movable drive sheave.

17. The crankshaft is equipped with a fixed collar, and the fixed driven sheave is engaged with the fixed collar. The movable collar is arranged around the fixed collar, and the movable driven sheave is engaged with the movable collar. The continuously variable transmission according to claim 15, comprising a plurality of pins extending from the fixed collar to each slot of the movable collar, wherein the movable collar and the movable driven sheave are configured to transmit power to the fixed collar and move along the crankshaft.

18. Furthermore, the housing is provided with a drive assembly positioned between the second side and the fixed drive sheave, wherein the drive assembly is configured to transmit power from the crankshaft to the countershaft so that the countershaft rotates faster and with less torque than the crankshaft. The continuously variable transmission according to claim 15, further comprising a driven assembly positioned between the first side of the housing and the fixed driven sheave around the crankshaft, wherein the driven assembly transmits power from the fixed driven sheave and the movable driven sheave to the drive wheel, and the drive wheel is configured to rotate slower and with higher torque than the fixed driven sheave and the movable driven sheave.

19. The continuously variable transmission according to claim 18, characterized in that the drive assembly is disposed within a first sealed portion of the housing configured to receive a lubricant, and the driven assembly is disposed within a second sealed portion of the housing configured to receive a lubricant.

20. The continuously variable transmission according to claim 15, characterized in that the belt has a V-shaped cross-section, and the inner surfaces of the fixed drive sheave and the movable drive sheave and the inner surfaces of the fixed drive sheave and the movable driven sheave are tapered in a manner complementary to the side surface of the V-shaped belt.

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