continuously variable bicycle transmission

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 applications related to continuously variable bicycle transmissions This application claims priority to U.S. Provisional Patent Application No. 63 / 421,031, filed October 31, 2022, which is incorporated herein by reference in its entirety. The present invention relates to a continuously variable transmission, particularly for bicycles, that has the ability to transmit power from a crankshaft to a rear hub at an infinitely variable speed ratio. [Background technology]

[0002] Some conventional bicycles have a chain connecting one sprocket on the crankshaft and one sprocket on the rear hub, transmitting power from the rider's pedaling at the crankshaft to the rear wheel at the rear hub, thereby propelling the bicycle forward. However, with only one sprocket on the crankshaft and one on the rear hub, there is only one gear ratio that transmits power to the rear wheel at the rear hub. This gear ratio can be optimized for a narrow range of operating conditions of the bicycle, but cannot be optimized for multiple ranges of operating conditions. For example, a high gear ratio, with a relatively large number of teeth on the rear hub sprocket, increases the torque required to propel the bicycle from a stationary position, but limits the rider's ability to ride the bicycle at high speeds. Conversely, a low gear ratio, with a relatively small number of teeth on the rear hub sprocket, is suitable for high speeds but reduces the rider's ability to launch the bicycle from a stationary position.

[0003] To solve this problem, conventional bicycles feature multiple sprockets on the crankshaft or rear hub, allowing for multiple gear ratios between the crankshaft and rear hub. This allows the rider to start the bicycle at a stationary position using a higher gear ratio, providing more torque to propel the bicycle from a stationary position. 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. This allows the rider to further increase the bicycle's speed, much like a traditional automobile shifts gears as it gains speed. However, even with multiple gears, the rider is limited to a limited number of gear ratios to choose from. These gear ratios are optimized for specific operating conditions and may not be suitable for a particular rider. Furthermore, multiple sprockets, derailleurs, and other shifting components increase the bicycle's complexity, weight, and potential for failure.

[0004] Another conventional system uses multiple spur or helical gears mounted on the crankshaft. This gear system operates like a car's transmission and requires complex shifters to change gear ratios. Like the sprockets and derailleurs mentioned above, this gear system only allows for a 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 herein do not use sprockets or gears for a limited number of gear ratios. Instead, the embodiments described herein have multiple sheave sets connected by a belt that can move through an infinite number of speed ratios, allowing the user to select the exact speed ratio appropriate for the current operating conditions. "Speed ​​ratio" refers to the relative mechanical advantage between the sheave sets and is similar to a gear ratio.

[0006] Other prior art systems for transmitting power can also be installed in the rear hub of a bicycle. One such system includes planetary gears within the rear hub and uses sensitive shifters to change the gear ratio, requiring the bicycle to coast without input power while moving in order for the shifters to change the gear ratio. As described herein, this embodiment includes a position motor that precisely controls the speed ratio. Furthermore, the position motor controls the speed ratio and can maintain a specific speed ratio during operation.

[0007] Another prior art 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 input and output of the system. However, this system requires specialized traction oil, has high internal forces that reduce the system's reliability and lifespan, and is heavy, inefficient, and expensive. The present embodiment provides a continuously variable transmission that does not require specialized oil and reduces internal forces, improving the reliability and lifespan of the transmission. Specifically, the drive assembly described herein increases the rotational speed of the sheaves and belt, reducing the torque on these components, thereby reducing damage and improving the reliability and lifespan of the transmission. Summary of the Invention

[0008] The present embodiment relates to a novel transmission that allows for continuous, infinitely variable speed ratio variation between the input crankshaft and the output drive wheels. Furthermore, the present embodiment provides 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 present transmissions are applicable to any small human-powered or electric vehicle equipped with a transmission.

[0009] One aspect of various embodiments herein provides a continuously variable transmission that includes multiple sheave sets and a belt, allowing infinite speed ratios to be continuously varied, enabling a user to control the speed ratio to suit the specific operating conditions of a bicycle. One sheave set is disposed around a crankshaft that is rotatable about the crankshaft axis, and the other sheave set is disposed around a countershaft that is rotatable about a counteraxis parallel to the crankshaft. Power is transmitted from the sheave set around the crankshaft, i.e., the drive sheave, to the sheave set around the countershaft, i.e., the driven sheave, via a belt. 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 the 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 from the countershaft. The movable drive sheave moves to accommodate the change in belt position, thereby establishing a higher speed ratio. Conversely, when the movable driven sheave is farther from the fixed driven sheave, the belt moves to contact the inner surface of the driven sheave that is closer to the countershaft. Again, the movable drive sheave moves to accommodate the change in belt position, thereby establishing a lower speed ratio. A biasing member acting on the movable drive sheave accommodates these speed ratio changes, as described in more detail herein.

[0011] One aspect of the embodiments herein provides a position motor that conveniently and accurately controls the position of a movable driven sheave along a counteraxis to set the speed ratio of a transmission. The position motor may be, for example, a servo motor with an output shaft rotatable about 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 disposed in a recess in the hub, and as the output shaft and eccentric cam rotate, the hub and movable driven sheave move along the counteraxis to set the speed ratio. Thus, the position motor can change the speed ratio over a range of bicycle speeds and input powers and maintain a desired speed ratio. Furthermore, the position motor can change the speed ratio while the bicycle is stationary or moving, and / or while the user is pedaling to power the transmission or simply coasting.

[0012] A further aspect of some embodiments herein is to reduce the torque acting on the sheaves and belt, 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. High torque acting on the sheaves and belt shortens the lifespan of these components. Furthermore, high torque acting on the sheaves can damage the position motor and other components. Therefore, increasing the speed reduces the torque on the sheaves and belt. The drive assembly transmits torque from the crankshaft to the drive sheave, and the drive assembly increases the rotational speed of the sheave relative to the crankshaft, while reducing the torque, improving the reliability and lifespan of the transmission.

[0013] The drive assembly can be positioned to accommodate various bicycle constraints. For example, embodiments of the derailleur are positioned at 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. As such, some components of the derailleur are constrained by certain dimensions, such as the distance between the crank arms connecting the pedals to the crankshaft and the clearance distance between the bottom bracket and the ground. Accordingly, in various embodiments, the drive assembly includes two planetary gear sets connected in series to transfer power from the crankshaft to the drive sheave. In these embodiments, the drive assembly may be referred to as a drive gear assembly. The use of two planetary gear sets allows for the necessary torque reduction while maintaining a sufficiently compact form factor for the derailleur. However, it should be understood that the present invention includes bicycle derailleur embodiments having more or fewer gear sets or other components, such as sprockets or belts, and also includes derailleur embodiments for other vehicles with other practical constraints.

[0014] Yet another aspect of the embodiments herein provides a driven assembly and output gear that transfers power from the driven sheave and countershaft to a drive wheel, which then drives the rear wheel to propel the vehicle. The rotational speed of the sheave and belt increases to reduce torque in the transmission, but torque must be increased to activate the drive wheel and propel the vehicle. The driven assembly is disposed around and engages 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 engages a first output gear disposed around the countershaft. A separate second output gear is disposed around the crankshaft and engages the first output gear. Finally, in various embodiments, the second output gear transfers power to the drive wheel to propel the bicycle. It will be understood that in some embodiments, a belt transfers power from the drive assembly to the driven sheave, or the driven assembly can include components such as a sprocket, belt, etc.

[0015] A further aspect of embodiments herein provides a controller for regulating and operating various components of the transmission, particularly the position motor. In some embodiments, the transmission includes a battery in communication with the controller that supplies power to the position motor, and a generator that engages a rotating component of the transmission and transmits 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. Additionally, the controller can send output signals to the position motor to control various aspects of the position motor, such as the speed or acceleration of the output shaft, the direction of rotation of the output shaft, etc.

[0016] Various devices can send one or more input signals to a controller, for example, to change the speed ratio of a transmission. For example, a shifter attached to the handlebars of a bicycle 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 a user to a crankshaft and sends an input signal to the controller. The controller can process the one or more input signals and control the flow of power to and output signal to a position motor to set the appropriate speed ratio of the transmission.

[0017] One aspect of the embodiments herein provides a continuously variable transmission having a drive sheave set disposed about a countershaft and a driven sheave set disposed about a crankshaft. The drive assembly transfers power from the crankshaft to the countershaft, which transfers power to the drive sheave. The drive sheave then transfers power via a belt to the driven sheave, which transfers power to a drive wheel, for example, via a driven assembly. This configuration, along with a position motor located adjacent to the movable drive sheave, 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 sheave, resulting in a transmission that is more responsive to user input and allows for faster speed ratio changes.

[0018] In embodiments in which the drive sheave is disposed about the countershaft, as well as in other embodiments, the drive and driven assemblies can include multiple gears, sprockets, belts, etc. to transmit power. In some embodiments, the drive assembly includes a first gear disposed about the crankshaft, a second gear disposed about the intermediate shaft and meshing with the first gear, a third gear disposed about the intermediate shaft, and a fourth gear disposed about 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 less torque than the crankshaft, thereby reducing wear on transmission components.

[0019] Similarly, the driven assembly can include multiple gears, sprockets, belts, etc., to transmit power. In some embodiments, the driven assembly includes a sun gear that receives power from the driven sheave, planet gears, a carrier connected to the planet gears, and a ring gear. The carrier serves as the output of the driven assembly and transmits power to a drive wheel, which rotates slower and with higher torque than the driven sheave. In other embodiments, the driven assembly spans between a countershaft and a crankshaft, with a first sprocket disposed about the countershaft and a second sprocket disposed about the crankshaft, and a synchronous belt connecting the sprockets. Power is transmitted from the countershaft to the first sprocket, the belt, and the second sprocket, which transmits power to the drive wheel, which rotates slower and with higher torque than the countershaft.

[0020] A first aspect of the present specification provides a continuously variable transmission for a bicycle, the continuously variable transmission for a bicycle comprising: a crankshaft rotatable about a crank axis; a drive gear assembly arranged around the crankshaft, the input of the drive gear assembly interlocking with the crankshaft and the output of the drive gear assembly configured to rotate faster and with less torque than the crankshaft; a driven sheave set arranged around the crankshaft and interlocking with the output of the drive gear assembly; a countershaft rotatable about a counter axis; a drive sheave set arranged around the countershaft and engaging with the countershaft; 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 a driven gear assembly arranged around the countershaft, the input of the driven gear assembly interlocking with the countershaft and the output of the driven gear assembly configured to rotate slower and with greater torque than the countershaft, the output of the driven gear assembly configured to transmit power to a drive wheel to propel the bicycle.

[0021] The transmission of the first aspect optionally includes a position motor, the driven sheave set including 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 countershaft to change the speed ratio between the drive sheave set and the driven sheave set.

[0022] A transmission of a first aspect may include one or more of the preceding embodiments, and optionally a biasing member, wherein the drive sheave set includes a fixed sheave and a movable sheave, the biasing member configured to act on the movable sheave along the crankshaft, and the movable sheave configured to change position along the crankshaft to adjust to a speed ratio set by the driven sheave set.

[0023] The transmission of the first aspect may include one or more of the preceding embodiments, and optionally, the drive gear assembly includes a first planetary gear set having a ring gear, a plurality of first planetary gears, a first carrier, and a first sun gear, the first carrier being an input of the drive gear assembly and configured to drive the 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; the second planetary gear set includes a plurality of second planetary gears, a second carrier, and a second sun gear, the second carrier engaging the first sun gear and the second carrier being configured to drive the 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 being an output of the drive gear assembly.

[0024] The transmission of the first aspect may include one or more of the preceding embodiments, and optionally, the first planetary gear set has a gear ratio and the second planetary gear set has a gear ratio, the gear ratio being between about 1:3.5 and 1:4.5.

[0025] The transmission of the first aspect may include one or more of the preceding embodiments, and optionally, the driven gear assembly comprises a planetary gear set having a ring gear, a plurality of planet gears, and a sun gear, the sun gear being an input of the driven gear assembly, the sun gear being configured to drive the plurality of planet gears, the plurality of planet gears being configured to drive the ring gear at a lower speed and with higher torque than the sun gear, and the ring gear being an output of the driven gear assembly.

[0026] The transmission of a first aspect may include one or more of the preceding embodiments, and optionally include a drive wheel disposed about the crankshaft, and an output gear disposed about the crankshaft and engaging the drive wheel, wherein teeth extending around an outer surface of the ring gear are configured to transfer power to the output gear, and wherein the output gear is configured to transfer power to the drive wheel to propel the bicycle.

[0027] A second aspect of the present specification provides a continuously variable transmission system for a bicycle, the system comprising: a crankshaft rotatable about a crankshaft axis; a fixed drive sheave and a movable drive sheave arranged about the crankshaft, the fixed drive sheave and the movable drive sheave being configured to receive power from the crankshaft; a countershaft rotatable about a countershaft axis; a fixed driven sheave and a movable driven sheave arranged about the countershaft; 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 connecting the fixed drive sheave and the movable drive sheave to the fixed driven sheave and the movable driven sheave. The drive sheave is configured to transmit power to the sheaves, and the speed ratio between the fixed and movable drive sheaves and the fixed and movable driven sheaves is continuously variable, and includes a biasing member configured to act on the movable drive sheave along the crankshaft, the movable drive sheave changes position along the crankshaft to correspond to the speed ratio set by the fixed and movable driven sheave, and includes a position motor engaged with the movable driven sheave, and the position motor is configured to move the movable driven sheave along the countershaft to change the speed ratio between the fixed and movable drive sheaves and the fixed and movable driven sheaves.

[0028] The transmission of the second aspect may optionally be configured such that the position motor is a servo motor having an output shaft, the rotation of which can move the movable driven sheave along the counter axis.

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

[0030] The transmission of the second aspect can include one or more of the preceding embodiments, and optionally a controller in communication with the position motor and a shifter in communication with the controller, the shifter configured to send an input signal to the controller, and the controller configured to cause the position motor to move the movable driven sheave along the countershaft to change the speed ratio between the fixed and movable drive sheaves and the fixed and movable driven sheaves.

[0031] The transmission of a second aspect can include one or more of the preceding embodiments, and optionally include a controller in communication with the position motor, and a torque sensor operably engaged with the crankshaft and in communication with the controller, the torque sensor configured to send an input signal to the controller, and the controller configured to cause the position motor to move the movable driven sheave along the countershaft to change the speed ratio between the fixed and movable drive sheaves and the fixed and movable driven sheaves.

[0032] The transmission of a second aspect may include one or more of the preceding embodiments, and optionally include a plurality of pins protruding from the countershaft and a plurality of slots extending through a portion of the movable driven sheave, the plurality of pins being disposed within a respective plurality of slots such that the movable driven sheave is movable relative to the countershaft along the countershaft.

[0033] The transmission of a second aspect may include one or more of the foregoing embodiments, and optionally each slot of the plurality of slots may extend along a line that is not parallel to the counter axis.

[0034] The transmission of the second aspect may include one or more of the foregoing embodiments, and optionally, the portion of the movable driven sheave having the slot may be a cylindrical portion and / or a portion disposed around the countershaft.

[0035] The transmission of the second aspect may include one or more of the foregoing embodiments, optionally wherein the portion of the movable driven sheave having the slot is the portion that does not contact the belt.

[0036] A third aspect of the present 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 about a crankshaft, the movable drive sheave being disposed between the first side of the housing and the fixed drive sheave; a countershaft at least partially disposed within the housing and rotatable about a countershaft; a fixed driven sheave and a movable driven sheave disposed about the countershaft; the fixed driven sheave being disposed between the first side of the housing and the movable driven sheave; the bicycle comprises a plurality of pins projecting from the movable driven sheave and a plurality of slots extending through the movable driven sheave, the plurality of pins being disposed within each of the plurality of slots such that the movable driven sheave is movable relative to the countershaft along a counter axis; a belt connecting the two drive sheaves and the two driven sheaves, the belt being 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 such that power is transmitted to the countershaft to propel the bicycle.

[0037] The transmission of the third embodiment may optionally be such that the portion of the movable driven sheave having the slot is disposed around the cylindrical portion and / or the countershaft.

[0038] The transmission of the third aspect may include one or more of the foregoing embodiments, optionally wherein the portion of the movable driven sheave having the slot is the portion that does not contact the belt.

[0039] A third aspect of the transmission comprises one or more of the preceding embodiments, and optionally a position motor engaged with the movable driven sheave, the position motor configured to move the movable driven sheave along the countershaft to change the speed ratio between the two drive sheaves and the two driven sheaves, and a biasing member configured to act on the movable drive sheave along the 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 transmission of a third aspect may include one or more of the preceding embodiments and, optionally, a drive gear assembly disposed between the first side of the housing and the movable drive sheave, wherein an input of the drive gear assembly is configured to receive power from the crankshaft and an output of the drive gear assembly is configured to rotate faster and with less torque than the crankshaft, and the two drive sheaves are geared with the output of the drive gear assembly.

[0041] A transmission of a third aspect can include one or more of the preceding embodiments and, optionally, a driven gear assembly disposed about the countershaft between the first side of the housing and the fixed driven sheave, wherein an input of the driven gear assembly engages the countershaft and an output of the driven gear assembly is configured to rotate at a slower speed and with higher torque than the countershaft.

[0042] The transmission of a third aspect includes one or more of the foregoing embodiments, and optionally, the drive gear assembly and the driven gear assembly are disposed in an enclosed portion of a housing that is at least partially filled with a lubricant.

[0043] The transmission of a third aspect may include one or more of the preceding embodiments, optionally 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 the present specification is to provide a continuously variable transmission for a bicycle, comprising: a crankshaft rotatable about a crankshaft; a countershaft rotatable about a countershaft; a drive assembly having an input coupled to the crankshaft and an output coupled to the countershaft, wherein the crankshaft drives the drive assembly, and the drive assembly drives the countershaft to rotate the countershaft at a higher speed and with lower torque than the crankshaft; a drive sheave set disposed around the countershaft and engaging with the countershaft; a driven sheave set disposed 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; and a driven assembly disposed around the crankshaft, wherein the input of the driven assembly engages with 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] The transmission of the fourth aspect can optionally include a position motor, wherein the drive sheave set has 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 and driven sheave set.

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

[0047] A transmission of a fourth aspect may include one or more of the preceding embodiments, and optionally, the drive assembly includes a first gear disposed about the crankshaft and being an input of the drive assembly, a second gear disposed about the intermediate shaft and engaging the intermediate shaft, the crankshaft driving the first gear and the first gear driving the second gear so that the intermediate shaft rotates at a higher speed and with lower torque than the crankshaft, a third gear disposed about the intermediate shaft and engaging the intermediate shaft, and a fourth gear disposed about the countershaft and being an output of the drive assembly, the intermediate shaft driving the third gear and the third gear driving the fourth gear so that the countershaft rotates at a higher speed and with lower torque than the intermediate shaft.

[0048] The transmission of the fourth aspect may include one or more of the foregoing embodiments, and optionally the gear ratio between the input and output of the drive assembly may be between about 1:3.8 and 1:14.5.

[0049] A transmission of a fourth aspect may include one or more of the preceding embodiments, and optionally, 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 an input of the driven assembly, the sun gear being configured to drive the plurality of planetary gears relative to the ring gear such that the carrier rotates slower and with greater torque than the sun gear, and the carrier being an output of the drive assembly.

[0050] The transmission of a fourth aspect can include one or more of the preceding embodiments, and optionally, the driven assembly includes a first sprocket that is an input of the driven assembly, a second sprocket that is an output of the driven assembly, and a belt connecting the first sprocket and the second sprocket.

[0051] A fifth aspect of the present disclosure provides a continuously variable transmission system for a bicycle, the system including a crankshaft rotatable about a crankshaft, a countershaft rotatable about a countershaft, a fixed drive sheave and a movable drive sheave arranged about the countershaft, the fixed drive sheave and the movable drive sheave being configured to receive power from the countershaft, a fixed driven sheave and a movable driven sheave arranged about the crankshaft, 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 connecting the fixed drive sheave and the movable drive sheave to the fixed driven sheave and the movable driven sheave. a crankshaft configured to transmit power to the fixed and movable drive sheave, the speed ratio between the fixed and movable drive sheave and the fixed and movable driven sheave being continuously variable, the crankshaft including a biasing member configured to act on the movable driven sheave along the crankshaft, the movable driven sheave changing position along the crankshaft to correspond to the speed ratio set by the fixed and movable drive sheave, and a position motor engaged with the movable drive sheave, the position motor configured to move the movable drive sheave along the countershaft to change the speed ratio between the fixed and movable drive sheave and the fixed and movable driven sheave.

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

[0053] The transmission of a fifth aspect may include one or more of the preceding embodiments, and optionally include an eccentric cam connected to the output shaft of the servo motor and a hub configured to move along the counter axis, the eccentric cam extending into a recess in the hub, and rotation of the output shaft causes the eccentric cam to rotate, causing the hub to move the movable drive sheave along the counter axis to change the speed ratio between the fixed and movable drive sheaves and the fixed and movable driven sheaves.

[0054] The transmission of a fifth aspect can include one or more of the preceding embodiments, and optionally a controller in communication with the position motor and a shifter in communication with the controller, the shifter configured to send an input signal to the controller, and the controller configured to cause the position motor to move the movable drive sheave along the counter shaft to change the speed ratio between the fixed and movable drive sheaves and the fixed and movable driven sheaves.

[0055] The transmission of a fifth aspect can include one or more of the preceding embodiments, and optionally include a controller in communication with the position motor, and a torque sensor operably engaged with the crankshaft and in communication with the controller, the torque sensor configured to send an input signal to the controller, and the controller configured to cause the position motor to move the movable drive sheave along the countershaft to change the speed ratio between the fixed and movable drive sheaves and the fixed and movable driven sheaves.

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

[0057] The transmission of the fifth aspect may include one or more of the preceding embodiments, and optionally, the biasing member is a spring that generates either a linearly varying force or a non-linearly varying force with displacement.

[0058] A sixth aspect of the present specification provides a continuously variable transmission for a bicycle, the continuously variable transmission comprising: a housing extending from a first side to a second side; a crankshaft rotatable about a crank axis, the crankshaft at least partially disposed within the housing; a countershaft rotatable about a counter axis, the countershaft disposed within the housing; a fixed drive sheave and a movable drive sheave disposed about the countershaft; the fixed drive sheave and the movable drive sheave are disposed within the housing; the movable drive sheave is disposed between the fixed drive sheave and the first side of the housing; the fixed drive sheave and the movable drive sheave are configured to receive power from the countershaft; and a fixed driven sheave disposed about the crankshaft. a fixed drive sheave and a movable driven sheave, the fixed driven sheave and the movable driven sheave are disposed within the housing, the movable driven sheave is disposed between the fixed driven sheave and the second side of the housing, a belt configured to transmit power from the fixed drive sheave and the movable driven sheave to the fixed driven sheave and the movable driven sheave, 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, and a position motor disposed between the movable drive sheave and the first side of the housing, the position motor configured 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.

[0059] The transmission of the sixth aspect can optionally include a biasing member configured to act on the movable driven sheave along the crankshaft, the biasing member being disposed between the movable driven sheave and the second side of the housing, and 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 a sixth aspect may include one or more of the preceding embodiments and, optionally, a fixed collar disposed about the crankshaft, the fixed driven sheave engaged with the fixed collar and comprising a movable collar disposed about the fixed collar, the movable driven sheave engaged with the movable collar and comprising a plurality of pins extending from the fixed collar into respective slots in the movable collar, the movable collar and the movable driven sheave configured to transfer power to the fixed collar and move along the crankshaft.

[0061] A transmission of a sixth aspect may include one or more of the preceding embodiments, and optionally include a drive assembly disposed between the second side of the housing and the fixed drive sheave, the drive assembly configured to transfer power from the crankshaft to the countershaft so that the countershaft rotates faster and with less torque than the crankshaft, and a driven assembly disposed about the crankshaft between the first side of the housing and the fixed driven sheave, the driven assembly configured to transfer power from the fixed driven sheave and the movable driven sheave to the drive wheel so that the drive wheel rotates slower and with more torque than the fixed driven sheave and the movable driven sheave.

[0062] A transmission of a sixth aspect may include one or more of the preceding embodiments, optionally wherein the drive assembly is disposed in a first sealing portion of the housing configured to receive the lubricant, and the driven assembly is disposed in a second sealing portion of the housing configured to receive the lubricant.

[0063] A sixth aspect of the transmission includes one or more of the preceding embodiments, optionally wherein the belt has a V-shaped cross section, and the inner surfaces of the fixed and movable drive sheaves and the inner surfaces of the fixed and movable driven sheaves are tapered to complement the sides of the V-shaped belt.

[0064] As used herein, the terms "at least one," "one or more," and "and / or" are open-ended expressions that have both conjunctive and disjunctive functions. For example, the phrases "at least one of A, B, and C," "at least one of A, B, or C," "one or more of A, B, and C," "one or more of A, B, or 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 noted, all numbers expressing quantities, dimensions, conditions, and the like used in the specification and claims are to be understood as being modified in all instances by the term "about."

[0066] As used herein, the reference to "a" entity or "an" entity refers to one or more of that entity. Thus, the terms "a" (or "an"), "one or more," and "at least one" are used interchangeably herein.

[0067] As used herein, "including," "comprises," "has," and variations thereof are intended to encompass the items listed thereafter and equivalents thereof, as well as additional items. Thus, "including," "comprises," "has," and variations thereof can be used interchangeably herein. As used herein, "engages" and variations thereof are intended to encompass direct or indirect connections between components.

[0068] The term "means" as used herein is to be understood to be interpreted as broadly as possible pursuant to 35 U.S.C. §112(f). Accordingly, any claim containing the term "means" is intended to encompass all structure, material, or acts described herein, and all equivalents thereof. Furthermore, structures, materials, or acts, and equivalents thereof, are intended to include everything described in the Summary, Brief Description of the Drawings, Detailed Description, Abstract, and the claims themselves.

[0069] These and other advantages will be apparent from the disclosure of the invention contained herein. The above embodiments, objects, and configurations are not complete or exhaustive. The Summary of the Invention is not intended to be, and should not be construed as, representative of the entire scope and breadth of the present disclosure. Furthermore, references herein to "the present invention" or aspects thereof should be understood to refer to certain embodiments of the present invention / disclosure and should not be construed as necessarily limiting all embodiments to the particular description. The present invention is described in various levels of detail in the Summary of the Invention, the accompanying drawings, and the Detailed Description, and the inclusion or non-inclusion of elements, components, etc. in the Summary of the Invention is not intended to limit the scope of the invention. Further aspects of the present invention will become more readily apparent when read in conjunction with the Detailed Description, particularly when read in conjunction with the drawings.

[0070] It should be understood that any feature or aspect described herein can be claimed in combination with any other feature or aspect described herein, regardless of whether those features or aspects are from the same embodiment.

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

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

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

[0074] It should be understood that the drawings are not necessarily to scale and may be modified in various ways. In some instances, details that are not necessary for an understanding of the invention or that obscure other details may be omitted. Of course, it should be understood that the invention is not necessarily limited to the particular embodiments described herein.

[0075] 2. Bicycles 4 crankshaft 6 pedals 8 driving wheels 10 Chain 12 rear hub 14 rear wheels 16 Transmission 18 Housing 20 Part 1 22 Part 2 24 crankshaft 26 1st planetary gear set 28 2nd planetary gear set 30 Fixed drive sheave 32 Movable drive sheave 34 biasing member 36 Belt 38 Countershaft 40 Counter shaft 42 Fixed driven sheave 44 Movable driven sheave 46 position motor 48 3rd Planetary Gear Set 50 1st output gear 52 Second output gear 54 First Career 56 Ring gear 58a, 58b First planetary gear 58c, 58d 1st planetary gear 60 First Sun Gear 62 Second Career 64a, 64b Second planetary gear 66 Second Sun Gear 68 Drive shaft 70 Drive pin 72 drive slot 74 Follower slot 76 Follower pin 77 screws 78 Hub 80 output shaft 82 Eccentric cam 84 recess 86 Third Sun Gear 88a, 88b 3rd planetary gear 90 3rd ring gear 92 Input section 94 Controller 96 Battery 98 Electric Motor 100 gears 102 Housing 104 crankshaft 106 Part 1 107 1st side 108 Part 2 109 Second side 110 crankshaft 112 Intermediate shaft 114 Intermediate shaft 116 Countershaft 118 Counter shaft 120 drive wheel 122 Drive Gear Assembly 124 1st Gear 126 2nd Gear 128 3rd Gear 130 4th Gear 132 Fixed drive sheave 134 Movable drive sheave 136 position motor 140 Hub 142 output shaft 144 Eccentric Cam 146 Belt 148 First driven sheave 150 Movable driven sheave 152 biasing member 154 Driven Gear Assembly 156 Sun Gear 158 Planetary Gear 160 Careers 162 Ring Gear 164 1st sealed part 166 Second sealed part 168 recess 170 fixed color 172 pins 174 Movable Collar 176 slots 177 Slot shaft 178 Transmission 180 Housing 182 crankshaft 184 Crankshaft 186 Countershaft 188 Counter shaft 190 drive wheel 192 Drive Gear Assembly 194 Fixed drive sheave 196 Movable drive sheave 198 biasing member 200 Belt 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] While the following text provides detailed descriptions of numerous different embodiments, it should be understood that the legal scope of the descriptions is defined by the language of the claims set forth at the end of this specification. The detailed descriptions are to be construed as exemplary only and are not exhaustive, as it would be impractical, if not impossible, to cover every possible embodiment of a transmission. Using current technology, or technology developed after the filing date of this patent, numerous alternative embodiments can be implemented and are within the scope of the claims. Furthermore, any combination of features shown in the various figures can be used to create additional embodiments herein. Thus, the dimensions, aspects, and features of one embodiment of a transmission can be combined with the dimensions, aspects, and features of another embodiment of a transmission to create a claimed embodiment.

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

[0078] In some embodiments, bicycle 2 includes multiple sprockets on rear hub 12 and / or crankshaft 4, and a gear shifting system moves chain 10 between these various sprockets to change the gear ratio between rear hub 12 and crankshaft 4. Derailleur 16 herein eliminates the need for multiple sprockets on rear hub 12 and / or crankshaft 4. However, it will be understood that this embodiment may be used with multiple sprockets on rear hub 12 and / or crankshaft along with a gear shifting system. Furthermore, it will be understood that this embodiment may be used with an electric motor, controller, and / or battery, such as those found on an electric bicycle, as well as other components found on the bicycle.

[0079] FIG. 2A is a side view of a continuously variable transmission 16 of the present specification. The transmission 16, including the crankshaft 4, drive wheel 8, and other components described herein, changes the speed ratio of the transmission 16, whether the bicycle is stationary or traveling at a particular speed, and coordinates the user's effort with the bicycle's motion. In various embodiments, a user can customize the bicycle by selecting, for example, the crankshaft 4, drive wheel 8, pedals, or crank arms connecting the pedals to the crankshaft 4. Thus, the term "transmission" can include embodiments that include or do not include these components. Also shown in FIG. 2A is the line AA.

[0080] 2B is a horizontal cross-sectional view of continuously variable transmission 16 taken along line AA in FIG. 2A. Crankshaft 4 is rotatable about crank axis 24, and drive wheel 8 is disposed around crankshaft 4. Additionally, multiple components connect power applied by a user to crankshaft 4 with drive wheel 8, transmitting power to the rear hub to propel the bicycle forward.

[0081] The transmission 16 includes a set of drive sheaves 30, 32 that drive a belt 36, which transmits power to a set of driven sheaves 42, 44. The set of driven sheaves 42, 44 continuously varies and defines a speed ratio between the sheave sets, and the sheave and belt 36 system functions more efficiently at higher rotational speeds. Specifically, higher rotational speeds result in lower forces, or torque, improving the reliability and lifespan of the transmission 16 components. Thus, in some embodiments, the drive assembly has an input that engages the crankshaft 4 and an output that engages the drive sheaves 30, 32, which rotate at a higher speed and with less torque than the crankshaft. 2B, the drive assembly (which in this example may also be referred to as a drive gear assembly) includes a first planetary gearset 26 and a second planetary gearset 28, with the input of the first planetary gearset 26 engaging the crankshaft 4 and the output engaging the input of the second planetary gearset 28, which in turn has an output engaging a set of drive sheaves 30, 32.

[0082] In some embodiments, the derailleur 16 is located in the bottom bracket of the bicycle frame, and the crankshaft 4 passes through the derailleur 16. Therefore, the drive gear assembly is constrained by the circumferential location of 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 certain bicycle components must be connected in specific configurations and certain components must maintain clearance distances from the ground. Therefore, the series of two planetary gearsets 26, 28 achieves an overall gear reduction of between approximately 1:12.2 and 1:20.3 to satisfy these constraints. In various embodiments, the gear ratio of each planetary gearset 26, 28 is between approximately 1:3.5 and 1:4.5. In some embodiments, the gear ratio of each planetary gearset 26, 28 is approximately 1:4. In some embodiments, each planetary gearset 26, 28 has the same gear ratio, while in other embodiments, each planetary gearset 26, 28 has a different gear ratio.

[0083] While two planetary gear sets 26, 28 are depicted in the figures, 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 includes a single planetary gear set or a system of spur gears to provide the desired gear ratio. Furthermore, it should be understood that the gear ratios identified above are exemplary in nature. For example, the gear ratio of a single planetary gear set can range from approximately 1:2 to 1:20.

[0084] Many components of the transmission 16 are disposed within a housing 18, which may have a first portion 20 on a first side and a second portion 22 on a second side. The first and second planetary gear sets 26, 28 are disposed within the first portion 20 of the transmission 16 such that the first portion 20 is sealed and at least partially filled with lubricant to facilitate operation of the first and second planetary gear sets 26, 28, among other components described herein. The sheaves 30, 32, 42, 44 and the belt 36 are disposed within the second portion 22, which may not be sealed with lubricant, but may protect the sheaves 30, 32, 42, 44 and the belt 36 from the external environment.

[0085] The output of the drive gear assembly transfers power to a set of drive sheaves 30, 32. The fixed drive sheave 30 is rotatable about, but not movable along, the crankshaft 24. The movable drive sheave 32 is rotatable about, and movable along, the crankshaft 24. A biasing member 34 acts on the movable drive sheave 32, urging it toward the fixed drive sheave 30. The biasing member 34 can respond linearly or nonlinearly to force, such as a spring. The variable distance between the drive sheaves 30, 32 allows different speed ratios to be achieved through the set of driven sheaves 42, 44.

[0086] The set of driven sheaves 42, 44 includes a fixed driven sheave 42 that is rotatable about, but not movable along, the counter axis 40 of the countershaft 38, and a movable driven sheave 44 that is rotatable about, but movable along, the counter axis 40. A position motor 46 controls the position of the movable driven sheave 44 along the counter axis 40 to establish the speed ratio between the sheave sets and, therefore, 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 an output shaft, although it should be understood that this specification also encompasses embodiments in which the position motor is another device, such as an actuator.

[0087] The movable sheaves 32, 44 are positioned on opposite sides 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 encompasses embodiments in which the sheave locations are modified.

[0088] The set of driven sheaves 42, 44 powers the countershaft 38, which, like the sheaves 30, 32, 42, 44 and belt 36, rotates at a relatively high speed, reducing 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, more effectively delivering power to the drive wheel 8 and ultimately the rear hub 12 to propel the bicycle. In this embodiment, the driven assembly (which may be referred to as the driven gear assembly in this example) is a third planetary gearset 48. The output of the third planetary gearset 48 engages a first output gear 50, which rotates about the countershaft 40. The first output gear 50 engages a second output gear 52, which rotates about 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] 3A and 3B show the first planetary gearset 26. In this embodiment, the crankshaft 4 is connected to a carrier 54 of the first planetary gearset 26. The carrier 54 drives four planetary gears 58a-58d disposed within a ring gear 56. Other embodiments included herein may include more or fewer planetary gears 58a-58d. In this embodiment, the ring gear 56 is fixed relative to the housing and does not rotate. The four planetary gears 58a-58d rotate (i.e., drive) a first sun gear 60, which is the output of the first planetary gearset 26. In this embodiment, the gear ratio is 1:4, but it will be understood that this disclosure encompasses any gear ratio. Furthermore, it will be understood that this disclosure encompasses other arrangements of gears or other components other than a planetary gear unit to increase the rotational speed of the output.

[0090] FIG. 3C illustrates the second planetary gearset 28. The same ring gear 56 of the first planetary gearset 26 interfaces with components of the second planetary gearset 28. Thus, the terms "first planetary gearset" and "second planetary gearset" can, 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 FIG. 3B) is connected to a second carrier 62 of the second planetary gearset 28. The second carrier 62 drives two planetary gears 64a, 64b, which in turn drive a second sun gear 66, which serves as the output of the second planetary gearset 28. The second planetary gearset 28, and other planetary gearsets described herein, can include any number of planetary gears, for example, two, four, or more.

[0091] Figures 4A and 4B show the transmission components at a high speed ratio in Figure 4A and a low speed ratio in Figure 4B. In Figure 4A, the position motor 46 pulls the movable driven sheave 44 toward the fixed driven sheave 42, and this relative positioning between the driven sheaves 42, 44 pushes the belt 36 away from the axis of rotation of the driven sheaves 42, 44. As a result, the belt 36 contacts the inner surfaces of the driven sheaves 42, 44 at a location farther from the axis of rotation than in the low speed ratio shown in Figure 4B, and farther from the axis of rotation than the belt 36 in the drive sheaves 30, 32.

[0092] When the belt 36 is positioned in the driven sheaves 42, 44, the belt 36 is pulled inward in the drive sheaves 30, 32 toward the axis of rotation of the drive sheaves 30, 32. The inward pulling force of the belt 36 overcomes the force from the biasing member 34 acting on the movable drive sheave 32, causing the movable drive sheave 32 to move further (along the crankshaft) away from the fixed drive sheave 30. As a result, the belt 36 contacts the inner surface of the drive sheaves 30, 32 closer to the axis of rotation of the drive sheaves 30, 32 than in the low speed ratio shown in FIG. 4B and closer to the axis of rotation than the belt 36 in the driven sheaves 42, 44. The speed ratio of FIG. 4A is a higher speed ratio providing higher torque and lower rotational speed, which is suitable for a stationary or slow-moving vehicle.

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

[0094] Depending on the relative positions of the driven sheaves 42, 44, the force from the biasing member acting on the movable drive sheave 32 will move the movable drive sheave 32 closer to the fixed drive sheave 30, taking up the slack in the belt 36 allowed by the relative positions of the driven sheaves 42, 44. As a result, the belt 36 contacts the inner surfaces of the drive sheaves 30, 32 at a location farther from the axis of rotation of the drive sheaves 30, 32. In this regard, the force generated by the biasing member, which may have a linear or nonlinear response, acts in concert with the pulling force from the belt 36 caused by the relative positions of the driven sheaves 42, 44. The speed ratio of FIG. 4B is a lower speed ratio that provides lower torque and a higher rotational speed, making it more suitable for a moving vehicle to achieve higher speeds. As shown in the figures, the belt 36 may have a V-shaped cross section in which the inner and outer surfaces of the belt 36 are generally parallel to one another and the sides of the belt 36 are tapered to complement the angled inner surfaces of the sheaves 30, 32, 42, 44.

[0095] FIG. 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. From the drive side of the transmission, a 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 FIG. 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-and-slot arrangement. A plurality of pins 70 extend outward from the drive shaft 68 and are each positioned within a slot 72 in a portion of the movable drive sheave 32. The portion of the movable drive sheave 32 having the slots 72 may be cylindrical and / or disposed around the crankshaft. In some embodiments, the portion of the movable drive sheave 32 having the slots 72 is not in 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 transfer of power from the drive shaft 68 to the movable drive sheave 32, reducing the force required to move the movable drive sheave 32 along the crankshaft, and preventing slippage of the belt against the sheave as the transmission continuously changes between speed ratios.

[0096] Similarly, on the driven side of the transmission, pins 76 extend from the countershaft 38 and are positioned within respective slots 74 in a portion of the movable driven sheave 44. The portion of the movable driven sheave 44 with the slots 74 may be cylindrical and / or circumferentially disposed about the countershaft 38. In some embodiments, the portion of the movable driven sheave 44 with the slots 74 does not contact the belt 36. Thus, the movable driven sheave 44, along with the fixed driven sheave 42, transfers power from the belt to the countershaft 38. Furthermore, each slot 74 extends along a line that is not parallel to the countershaft axis. The angle and orientation of the slots 74 balance several functions, including effectively transferring power from the movable driven sheave 44 to the countershaft 38, reducing the force required to move the movable driven sheave 44 along the countershaft axis, and preventing slippage of the belt relative to the sheave when the transmission continuously changes between speed ratios.

[0097] The position motor 46 engages the hub 78 to move the movable driven sheave 44 along the countershaft to set the speed ratio of the transmission. The hub 78 is offset from the movable driven sheave 44 along the countershaft and is connected to the movable driven sheave 44 by a plurality of bolts 77. This connection provides space for connecting the fixed driven sheave (42 in FIGS. 4A and 4B) to the countershaft 38. While a plurality of bolts 77 are depicted, it should be understood that this specification encompasses other embodiments of the connection between the hub 78 and the movable driven sheave 44, such as a pin or other connection mechanism.

[0098] FIG. 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 about its longitudinal axis. An eccentric cam 82 is connected to the output shaft 80, so that 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 flat portion, and the eccentric cam 82 has a similarly shaped hole, so that the output shaft 80 fits into the eccentric cam 82 like a key fits into a keyhole. The keyed connection can be different shapes, such as a square, a triangle, a hexagon, or a concave / convex circle. The eccentric cam 82 is generally cylindrical, with the central axis of the cylinder 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 countershaft 40, that is, from side to side as shown in FIG.

[0099] The eccentric cam 82 is positioned in a recess 84 in the hub 78, restricting movement of the hub 78 to movement along the countershaft 40. Therefore, movement of the eccentric cam 82 parallel to the countershaft 40 is transmitted to the hub 78, which moves along the countershaft 40. As the hub 78 moves along the countershaft 40, the movable driven sheave (44 in FIGS. 4A and 4B) moves along the countershaft 40 in response to rotation of the output shaft 80 of the position motor 46 because the hub 78 is connected to the movable driven sheave (44 in FIGS. 4A and 4B). The position motor 46 can rotate the output shaft 80 with specific characteristics, such that the movable driven sheave (44 in FIGS. 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. Additionally, the position motor 46 can rotate the output shaft 80 to accommodate shifting or constantly changing speed ratios rather than moving between discrete speed ratios.

[0100] Although the position motor 46 is shown controlling the relative position of the driven sheave, in some embodiments the position motor 46 controls the relative position of the drive wheel, and the driven sheave automatically adjusts to the speed ratio set by the position motor 46 and the drive wheel.

[0101] 7 shows the driven gear assembly, which in this embodiment is the third planetary gearset 48. The countershaft 38 is connected to the input of the third planetary gearset 48, which in this embodiment is the 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 encompasses further embodiments, including embodiments in which the countershaft 38 and the third sun gear 86 are a single part.

[0102] Power transmitted to the third sun gear 86 rotates the two planetary gears 88 a, 88 b, which in turn rotates the ring gear 90. As a result, the ring gear 90 rotates slower and with more torque than the countershaft 38 and the third sun gear 86. The ring gear 90 is connected to the first output gear 50, which has teeth extending around its outer surface. In some embodiments, the ring gear 90 and the first output gear 50 are separate components, while in some embodiments, the ring gear 90 and the first output gear 50 are a single component, with the ring gear 90 having teeth extending around its inner and outer surfaces.

[0103] FIG. 8 shows a first output gear 50 connected to a second output gear 52, which meshes with a drive wheel 8. Power is transferred from the first output gear 50 to the second output gear 52, which can have various gear ratios, such as maintaining the same torque and speed, increasing torque while decreasing speed, or decreasing torque while increasing speed. The second output gear 52 then transfers power to the drive wheel 8. In the illustrated embodiment, the drive wheel 8 is secured to a portion of the second output gear 52 by a clip. However, it should be understood that this specification also encompasses embodiments in which the drive wheel 8 is secured to a portion of the second output gear 52 in other ways, and embodiments in which the drive wheel 8 and second output gear 52 are a single component. The second output gear 52 and drive wheel 8 are positioned around and rotatable about the crankshaft, similar to the typical placement of a drive wheel 8 on a conventional bicycle. The drive wheel 8 meshes with a chain to drive the rear hub of the bicycle, propelling the bicycle. Alternatively, power can be transmitted by a belt, such as a timing belt, in place of gears 50, 52. Additionally or alternatively, a belt system can be used to drive the rear hub and / or rear wheel of the bicycle in place of a drive wheel and chain.

[0104] 9 shows a schematic diagram of the controller 94 and other components that communicate with each other to operate the transmission. An input 92 sends an input signal to the controller 94, which analyzes the input signal and, depending on the analysis, the controller 94 enables power from a battery 96 to the position motor 46 and determines the speed ratio of the transmission.

[0105] The input 92 can be a variety of devices, and some embodiments herein can have multiple inputs 92. In one embodiment, the input 92 is a shift lever, such as a bicycle gear shifter. Thus, in various embodiments, a user can move a dial or paddle on the input shifter 92 to select a speed ratio. The physical movement of the dial or paddle is detected by a sensor on the input shifter 92, which sends an input signal to the controller 94. In some embodiments, the user selects from among a finite number of speed ratios to maintain a system familiar to users of traditional bicycles. In various embodiments, the user selects from among an infinite number of possible speed ratios. The input signal or other signals can be transmitted via a wired or wireless connection.

[0106] Based on the input signals, the controller 94 varies the amount of power provided from the battery 96 to the position motor 46. Additionally, based on the input signals, the controller 94 can simultaneously send output signals to the position motor 46 to direct the operation of the position motor 46, such as the direction of rotation of the output shaft, the speed of rotation of the output shaft, and the acceleration.

[0107] Another input 92 may include a torque sensor coupled to the crankshaft and drive wheel or a component connected to the drive wheel, such as a second output gear. When a 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 or no torque. In other situations, when climbing uphill, the user applies more torque and exerts significant effort. The torque sensor sends an input signal to the controller 94, which determines whether to take further action based on the input signal. Further action may include, among other actions described herein, changing the amount of power provided by the battery 96 to the position motor 46, for example, sending an output signal to the position motor 46 to reduce the speed ratio to assist with greater user effort. The torque sensor (input) 92 may also communicate information regarding the rotational speed of the crankshaft and / or drive wheel. In other embodiments, a separate cadence or speed sensor may be another input 92 to the controller 94. The input 92 may be any sensor that detects a characteristic of the transmission, the environment surrounding the transmission, or a user input.

[0108] Additionally, in various embodiments, the transmission works in conjunction with other components, such as an electric motor 98, as in the case of an electric bicycle, or e-bike. The electric motor is used in e-bikes to assist the user in various situations, such as pedaling uphill or starting from a standstill. This specification encompasses embodiments that combine the transmissions described herein with an electric motor 98 for the same purpose of assisting the user's efforts.

[0109] In some embodiments, user input and / or input from sensors, such as torque sensors, are sent to the controller 94 in the form of input signals. Based on these input signals, the controller 94 directs the transmission's position motor 46 and / or the electric motor 98 to assist the user in their efforts. In some embodiments, these include changing the transmission's speed ratio set by the position motor 46 and causing the electric motor to generate torque to assist in propelling the vehicle. In various embodiments, the bicycle's battery 96 can be charged by a wheel-located generator and / or regenerative braking.

[0110] Figure 10 is a perspective view of a transmission 100 for use in a vehicle such as a bicycle. Most of the components of transmission 100 are housed within a protective housing 102 to prevent contamination of the components by mud and other elements. A crankshaft 104 extends from housing 102, and a user rotates crankshaft 104 by pedaling and turning crank arms, thereby inputting mechanical power into transmission 100. Figure 10 also shows the B-line.

[0111] Figure 11 is a bottom cross-sectional view of transmission 100 taken along line BB in Figure 10. Housing 102 includes a first portion 106 on a first side 107 of transmission 100 coupled with a second portion 108 on a second side 109 of transmission 100. The terms "first side" and "second side" are relative and may be used interchangeably or substituted with other relative terms.

[0112] The crankshaft 104 rotates about the crankshaft 110, providing a mechanical power input to the transmission 100. As the crankshaft 104 rotates, power is first transmitted through a drive assembly 122 (referred to herein as a drive gear assembly 122), increasing the speed and reducing the torque of a belt 146 of the transmission 100. The increased speed allows for quicker and more responsive speed ratio changes, and the reduced torque reduces wear on the belt 146 and surrounding components. The drive gear assembly 122 is coupled to the crankshaft 104 and includes a first gear 124 disposed about its periphery. The outer teeth of the first gear 124 mesh with the outer teeth of a second gear 126 coupled to and disposed about the intermediate shaft 112. The intermediate shaft 112 is rotatable about the intermediate shaft 114. A third gear 128 is coupled to and disposed about the intermediate shaft 112. The teeth on the outer surface of the third gear 128 mesh with the teeth on the outer surface of a fourth gear 130 that is connected to and disposed around the countershaft 116. The countershaft 116 is rotatable about a counter axis 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, and the second gear 126 and the third gear 128 rotate together with the intermediate shaft 112. Therefore, the drive gear assembly 122 rotates the countershaft 116 at a higher speed and with less torque than the crankshaft 104. If the overall gear ratio of the drive gear assembly 122 is too low, torque reduction will be insufficient, resulting in greater forces, wear, and tear on the sheaves and belts. If the overall gear ratio is too high, components of the transmission 100 may be subjected to excessive speeds, 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 appreciated that other drive assemblies 122 can be used in place of the drive gear assembly 122 of Figure 11. For example, a planetary gear set gear train (26, 28 of Figure 2B) can be used as the drive assembly 122 of Figure 11. The drive assembly 122 can be located within an enclosed portion of the housing 102 that contains a lubricant. The terms drive assembly or driven assembly can include not only gear assemblies but also other assemblies that vary the speed and torque of rotating parts without having gears.

[0115] The countershaft 116 then transmits power to the fixed drive sheave 132 and the movable drive sheave 134, rotating the belt 146. The fixed drive sheave 132 rotates about but does not move along the countershaft 118, while the movable drive sheave 134 rotates about 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. If the distance between the drive sheaves 132, 134 is relatively large, the belt 146 will be positioned relatively low within the drive sheaves 132, 134, and the final output of the transmission 100 will be higher speed and lower torque. Conversely, if the distance between the drive sheaves 132, 134 is relatively small, the belt 146 will be positioned relatively high within the drive sheaves 132, 134, and the final output of the transmission 100 will be relatively slow and have high torque.

[0116] Position motor 136 sets the position of movable drive sheave 134 along counter axis 118 by rotating output shaft 142 that is mounted on eccentric cam 144, which in turn is mounted in a recess in hub 140. As will be explained in more detail with respect to FIG. 13 , eccentric cam 144 and hub 140 convert rotational motion of output shaft 142 into linear motion of movable drive sheave 134 along counter axis 118.

[0117] At the other end of belt 146 are movable driven sheave 150 and fixed driven sheave 148, which are disposed around crankshaft 104 and receive power from belt 146. A biasing member 152 exerts a force on movable driven sheave 150 with a linear or non-linear response, allowing movable driven sheave 150 to move along crankshaft 110 in concert with the movement of belt 146, as demanded by drive sheaves 132, 134 and position motor 136. Driven sheaves 148, 150 (sometimes referred to in this example as driven gear assembly 154) transfer power to driven assembly 154, which amplifies the torque to drive wheel 120 and reduces its speed.

[0118] To set the speed ratio and accommodate up and down movement of the belt 146 at 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 between a first side of the housing 102 and the fixed drive sheave 132, and the movable driven sheave 150 is positioned between a second side of the housing 102 and the fixed driven sheave 148. This positioning ensures stability of the belt 146 as the speed ratio changes.

[0119] In this embodiment, the driven gear assembly 154 includes a sun gear 156 that receives power from the driven sheaves 148 and 150, a plurality of planetary gears 158 that receive power from the sun gear 156, a fixed ring gear 162 within 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 and increase the torque of the drive wheel 120. 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 disposed in an enclosed portion of the housing 102 that contains a lubricant. As previously mentioned, different driven assemblies can be interchangeable. Additionally, the driven assembly is optional, and in some embodiments herein, a driven assembly is not included, in which 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. First gear 124 transfers power from crankshaft 104 to second gear 126 and intermediate shaft 112. Intermediate shaft 112 and third gear 128 then transfer power to fourth gear 130 and countershaft 116. As a result, countershaft 116 rotates at a higher speed and with less torque than crankshaft 104.

[0121] FIG. 13 is a perspective view of the position motor 136 and drive sheaves 132, 134. The output shaft 142 of the position motor 136 is positioned 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 power and rotates the output shaft 142 and eccentric cam 144, the eccentric cam 144 also moves along the counteraxis 118 of the countershaft 116. The eccentric cam 144 is positioned within a recess 168 in the hub 140, restricting its movement to a direction along the counteraxis 118. Therefore, as the eccentric cam 144 moves along the counteraxis 118, the hub 140 also moves along the counteraxis 118, and the movable drive sheave 134 also moves along the counteraxis 118, setting the speed ratio of the transmission. Position motor 136 can receive inputs from various components such as those described in FIG. 9 and rotate output shaft 142 at different speeds, accelerations, etc. to different rotational positions.

[0122] The fixed drive sheave 132 can be directly coupled to the countershaft 116 to receive power from the countershaft 116. Alternatively, the countershaft 116 can be provided with pins that extend outward and into slots in the movable drive sheave 134, similar to the countershaft (38) and movable driven sheave (44) in FIG. 5. Each slot extends along a line that is not parallel to the countershaft 118. The angle and orientation of the slots balance several functions, including efficiently transferring power from the countershaft 116 to the movable drive sheave 134, reducing the force required to move the movable drive sheave 134 along the countershaft 118, and preventing belt-to-sheave slippage as the transmission continuously changes between speed ratios. Additionally, the position motor 136 is located adjacent to the movable drive sheave 134, reducing the complexity of the components required to translate the motion of the output shaft 142 into the movable drive sheave 134.

[0123] FIG. 14 is a perspective view of a fixed driven sheave 148 that is rotatable about the crankshaft 104. The movable driven sheave (150 in FIG. 11) is not shown here, but rather is coupled to a movable collar 174 that has one or more slots 176. The movable driven sheave and movable collar 174 may be a single piece and may be collectively 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 coupled to a fixed collar 170 that has one or more pins 172 that extend outward into corresponding slots 176. The fixed driven sheave 148 and fixed collar 170 may be a single piece and may be collectively referred to as the fixed driven sheave 148. In this embodiment, the slots 176 and pins 172 are evenly spaced around the crankshaft 110. However, it will be appreciated that the spacing may be uneven and / or there may be any number of slots 176 and pins 172 .

[0124] The angle and orientation of slot 176 balances several functions, including efficiently transferring power from the drive sheave to the driven assembly, reducing the force required to move the movable drive sheave along crankshaft 110, and preventing belt-to-sheave slippage as the transmission continuously changes between speed ratios. Specifically, power received by the drive sheave is transferred to collars 170, 174, and fixed collar 170 transfers power to the sun gear (156 in FIG. 15) of the driven assembly described herein.

[0125] The angle between the axis 177 of the slot 176 and the crankshaft 110 can range from approximately 5 degrees to 50 degrees in some embodiments. In various embodiments, this angle is approximately 20 degrees. The angle between the axis of the slot of the movable drive sheave 134 and the counteraxis 118 can range from approximately 5 degrees to 50 degrees in some embodiments. In various embodiments, this angle is approximately 20 degrees. U.S. Patent Application Nos. 18 / 126,653 and 13 / 328,630 are each incorporated by reference herein in their entirety for the purposes of completeness of the specification.

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

[0127] FIG. 16 is a perspective view of a transmission 178 with a housing 180, which transmits power to a vehicle such as a bicycle. FIG. 17 is a cross-sectional view of the transmission 178 of FIG. 16 taken along line CC. A crankshaft 182 is rotatable about a crank axis 184, which rotates a drive assembly 192, which in this example may be referred to as a drive gear assembly 192. Specifically, the drive gear assembly 192 is a planetary gear set gear train, similar to the transmission of FIG. 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, with 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. Position motor 206 controls the position of movable driven sheave 204, which sets the speed ratio of the transmission. Driven sheaves 202, 204 rotate countershaft 186 about counter axis 188. Countershaft 186 rotates driven assembly 208 (which in this example may be referred to as driven sprocket assembly 208), which transmits power to drive wheel 190 and, for example, to the rear hub and rear wheel of a bicycle.

[0128] FIG. 18 is a perspective view of driven sprocket assembly 208 of transmission 178 of FIG. 16. Driven sprocket assembly 208 includes a drive sprocket 210 disposed about countershaft 186, a driven sprocket 214 disposed about crankshaft 182, and a synchronous belt 212 connecting sprockets 210 and 214. Thus, countershaft 186 rotates drive sprocket 210, which in turn rotates belt 212, driven sprocket 214, and drive wheel 190. Because drive sprocket 210 has fewer teeth than driven sprocket 214, drive wheel 190 rotates at a slower speed and with higher torque than countershaft 186. In this embodiment, the use of sprockets 210, 214, and belt 212 eliminates the need for sealed housings containing lubricants, as opposed to gear-to-gear drive or driven assemblies.

[0129] It will generally be understood that various components described herein may 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 may be used in the transmission shown in Figure 1 or Figure 10.

[0130] While various embodiments herein have been described in detail, it will be apparent that modifications and variations of these embodiments will occur to those skilled in the art. However, it is to be expressly understood that such modifications and variations are within the scope and spirit of the appended claims. Moreover, the invention described herein is capable of other embodiments and of being practiced or carried out in various ways. It is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be construed as limiting.

Claims

1. a crankshaft rotatable around a crank axis; a countershaft rotatable about a counter axis; a drive assembly having an input portion engaging the crankshaft and an output portion engaging 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 less torque than the crankshaft; a drive sheave set disposed about and engaging the countershaft; a driven sheave set disposed around the crankshaft; 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 a speed ratio between the drive sheave set and the driven sheave set is continuously variable; a driven assembly disposed about the crankshaft, the driven assembly input engaging the driven sheave set, the driven assembly output configured to rotate at a slower speed and with a higher torque than the driven sheave set, and the driven assembly output configured to transmit power to propel the bicycle; A continuously variable transmission for bicycles.

2. Further comprising a position motor, The drive sheave set A fixed sheave; a movable sheave that engages with the position motor; The position motor is configured to move the movable sheave along the countershaft to change the speed ratio between the drive sheave set and the driven sheave set.

2. The continuously variable transmission according to claim 1.

3. Further comprising a biasing member, The driven sheave set is A fixed sheave; 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 established by the drive sheave set.

2. The continuously variable transmission according to claim 1.

4. the drive assembly: a first gear disposed around the crankshaft and serving as an input of the drive assembly; and a second gear disposed around an intermediate shaft and engaging the intermediate shaft, wherein the crankshaft drives the first gear, and the first gear drives the second gear, such that the intermediate shaft rotates at a higher speed and with a lower torque than the crankshaft; The drive assembly further includes a third gear disposed about the intermediate shaft and engaging the intermediate shaft, and a fourth gear disposed about the countershaft and being an output of the drive assembly, the intermediate shaft driving the third gear, and the third gear driving the fourth gear, such that the countershaft rotates at a higher speed and with a lower torque than the intermediate shaft.

2. The continuously variable transmission according to claim 1.

5. 5. The continuously variable transmission of claim 4, wherein the gear ratio between the input and output of the drive assembly is between about 1:3.8 and 1:14.

5.

6. the driven assembly:

2. The continuously variable transmission of 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 an input of the driven assembly, the sun gear is configured to drive the plurality of planetary gears relative to the ring gear such that the carrier rotates slower and with greater torque than the sun gear, and the carrier is an output of the drive assembly.

7. the driven assembly: a first sprocket at the input of said driven assembly, and a second sprocket at the output of said driven assembly; a belt connecting the first sprocket and the second sprocket 2. The continuously variable transmission according to claim 1.

8. a crankshaft rotatable around a crank axis; a countershaft rotatable about a counter axis; a fixed drive sheave and a movable drive sheave disposed about 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 disposed around the crankshaft; a belt connecting the fixed and movable drive sheaves to the fixed and movable driven sheaves, the belt being configured to transmit power from the fixed and movable drive sheaves to the fixed and movable driven sheaves, and a speed ratio between the fixed and movable drive sheaves and the fixed and movable driven sheaves is continuously variable; a biasing member configured to act on the movable driven sheave along the crankshaft, the movable driven sheave varying in position along the crankshaft to accommodate a speed ratio established by the fixed drive sheave and the movable drive sheave; a position motor engaged with the movable drive sheave, the position motor configured to move the movable drive sheave along the countershaft to change the speed ratio between the fixed and movable drive sheaves and the fixed and movable driven sheaves; A continuously variable transmission system for bicycles.

9. 9. The continuously variable transmission system of claim 8, wherein the position motor is a servo motor having an output shaft, rotation of the output shaft causing the movable drive sheave to move along the countershaft.

10. an eccentric cam connected to the output shaft of the servo motor; 10. The continuously variable transmission system of claim 9, further comprising: a hub configured to move along the counter shaft, the eccentric cam extending into a recess in the hub, and rotation of the output shaft causing the eccentric cam to rotate, which in turn causes the hub to move the movable drive sheave along the counter shaft and change the speed ratio between the fixed and movable drive sheaves and the fixed and movable driven sheaves.

11. a controller in communication with the position motor; and a shifter in communication with the controller, the shifter configured to send an input signal to the controller, the controller configured to cause the position motor to move the movable drive sheave along the countershaft to change the speed ratio between the fixed and movable drive sheaves and the fixed and movable driven sheaves.

9. The continuously variable transmission system according to claim 8.

12. further comprising: a controller in communication with the position motor; 9. The continuously variable transmission system of claim 8, further comprising: a torque sensor operatively engaged with the crankshaft and in communication with the controller, the torque sensor configured to send an input signal to the controller, the controller configured to cause the position motor to move the movable drive sheave along the countershaft to vary the speed ratio between the fixed and movable drive sheaves and the fixed and movable driven sheaves.

13. a drive assembly having an input engaging said crankshaft and an output engaging said countershaft, said crankshaft driving said drive assembly, said drive assembly driving said countershaft, said drive assembly causing said countershaft to rotate at a higher speed and with less torque than said crankshaft; 9. The continuously variable transmission system of claim 8, further comprising a driven assembly disposed around the crankshaft, wherein an input of the driven assembly engages the fixed driven sheave and the movable driven sheave, and an output of the driven assembly is configured to rotate at a slower speed and with a higher torque than the fixed driven sheave and the movable driven sheave, and wherein the output of the driven assembly is configured to transmit power to propel the bicycle.

14. 9. The continuously variable transmission system according to claim 8, wherein the biasing member is a spring that generates a force that changes either linearly or non-linearly depending on the displacement.

15. a housing extending from a first side to a second side; a crankshaft rotatable about a crank axis, the crankshaft being at least partially disposed within the housing; a countershaft rotatable about a counter axis, the countershaft being disposed within the housing; a fixed drive sheave and a movable drive sheave disposed about the countershaft, the fixed drive sheave and the movable drive sheave being disposed within the housing, the movable drive sheave being disposed between the fixed drive sheave and the first side of the housing, the fixed drive sheave and the movable drive sheave being configured to receive power from the countershaft; a fixed driven sheave and a movable driven sheave disposed around the crankshaft, the fixed driven sheave and the movable driven sheave being disposed within the housing, and the movable driven sheave being disposed between the fixed driven sheave and the second side of the housing; a belt configured to transmit power from the fixed and movable drive sheaves to the fixed and movable driven sheaves, wherein a speed ratio between the fixed and movable drive sheaves and the fixed and movable driven sheaves is continuously variable; a position motor disposed between the movable drive sheave and the first side of the housing, the position motor configured to move the movable drive sheave along the countershaft to change the speed ratio between the fixed and movable drive sheaves and the fixed and movable driven sheaves. A continuously variable transmission for bicycles.

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

17. a fixed collar disposed about the crankshaft, the fixed driven sheave engaged with the fixed collar; a movable collar disposed around the fixed collar, the movable driven sheave being engaged with the movable collar; 16. The continuously variable transmission of claim 15, further comprising a plurality of pins extending from the fixed collar into respective slots in the movable collar, the movable collar and the movable driven sheave being configured to transfer power to the fixed collar and move along the crankshaft.

18. further comprising a drive assembly disposed between the second side of the housing and the fixed drive sheave, the drive assembly configured to transfer power from the crankshaft to the countershaft so that the countershaft rotates faster and with less torque than the crankshaft; 16. The continuously variable transmission of claim 15, further comprising a driven assembly disposed about the crankshaft between the first side of the housing and the fixed driven sheave, the driven assembly transmitting power from the fixed and movable driven sheave to a drive wheel configured to rotate slower and with higher torque than the fixed and movable driven sheave.

19. 19. The continuously variable transmission of claim 18, wherein the drive assembly is disposed within a first sealing portion of the housing configured to receive a lubricant, and the driven assembly is disposed within a second sealing portion of the housing configured to receive a lubricant.

20. 16. The continuously variable transmission according to claim 15, wherein 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 to be complementary to the side surfaces of the V-shaped belt.

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