Abstract: A ball-planetary continuously variable transmission (CVT) capable of stable control in forward and reverse rotation over a range of speed ratios including underdrive and overdrive is provided. Imparting a skew angle (zeta) causes unbalanced forces that change the tilt angle (gamma), resulting in a change in speed ratio of the CVT. Angularly orientating a control system of the CVT with a positive offset angle (psi) configures the CVT for operation in a first direction of rotation or angularly orientating the control system with a negative offset angle (psi) configures the CVT for operation in a reverse direction of rotation. A control system for configuring the offset angle (psi) may lead or trail the planets. The control system may configure a larger offset angle for more stable control or may configure a smaller offset angle for higher sensitivity in potential rollback scenarios.

Abstract: A ball-planetary continuously variable transmission (CVT) capable of stable control in forward and reverse rotation over a range of speed ratios including underdrive and overdrive is provided. Imparting a skew angle (zeta) causes unbalanced forces that change the tilt angle (gamma), resulting in a change in speed ratio of the CVT. Angularly orientating a control system of the CVT with a positive offset angle (psi) configures the CVT for operation in a first direction of rotation or angularly orientating the control system with a negative offset angle (psi) configures the CVT for operation in a reverse direction of rotation. A control system for configuring the offset angle (psi) may lead or trail the planets. The control system may configure a larger offset angle for more stable control or may configure a smaller offset angle for higher sensitivity in potential rollback scenarios.

Abstract: Inventive embodiments are directed to components, subassemblies, systems, and/or methods for continuously variable transmissions (CVT). In one embodiment, a main axle is adapted to receive a shift rod that cooperates with a shift rod nut to actuate a ratio change in a CVT. In another embodiment, an axial force generating mechanism can include a torsion spring, a traction ring adapted to receive the torsion spring, and a roller cage retainer configured to cooperate with the traction ring to house the torsion spring. Various inventive idler-and-shift-cam assemblies can be used to facilitate shifting the ratio of a CVT. Embodiments of a hub shell and a hub cover are adapted to house components of a CVT and, in some embodiments, to cooperate with other components of the CVT to support operation and/or functionality of the CVT. Among other things, shift control interfaces and braking features for a CVT are disclosed.

Abstract: Inventive embodiments are directed to components, subassemblies, systems, and/or methods for continuously variable transmissions (CVT). In one embodiment, a main axle is adapted to receive a shift rod that cooperates with a shift rod nut to actuate a ratio change in a CVT. In another embodiment, an axial force generating mechanism can include a torsion spring, a traction ring adapted to receive the torsion spring, and a roller cage retainer configured to cooperate with the traction ring to house the torsion spring. Various inventive idler-and-shift-cam assemblies can be used to facilitate shifting the ratio of a CVT. Embodiments of a hub shell and a hub cover are adapted to house components of a CVT and, in some embodiments, to cooperate with other components of the CVT to support operation and/or functionality of the CVT. Among other things, shift control interfaces and braking features for a CVT are disclosed.

Abstract: A ball-planetary continuously variable transmission (CVT) capable of stable control in forward and reverse rotation over a range of speed ratios including underdrive and overdrive is provided. Imparting a skew angle (zeta) causes unbalanced forces that change the tilt angle (gamma), resulting in a change in speed ratio of the CVT. Angularly orientating a control system of the CVT with a positive offset angle (psi) configures the CVT for operation in a first direction of rotation or angularly orientating the control system with a negative offset angle (psi) configures the CVT for operation in a reverse direction of rotation. A control system for configuring the offset angle (psi) may lead or trail the planets. The control system may configure a larger offset angle for more stable control or may configure a smaller offset angle for higher sensitivity in potential rollback scenarios.

Abstract: A ball-planetary continuously variable transmission (CVT) capable of stable control in forward and reverse rotation over a range of speed ratios including underdrive and overdrive is provided. Imparting a skew angle (zeta) causes unbalanced forces that change the tilt angle (gamma), resulting in a change in speed ratio of the CVT. Angularly orientating a control system of the CVT with a positive offset angle (psi) configures the CVT for operation in a first direction of rotation or angularly orientating the control system with a negative offset angle (psi) configures the CVT for operation in a reverse direction of rotation. A control system for configuring the offset angle (psi) may lead or trail the planets. The control system may configure a larger offset angle for more stable control or may configure a smaller offset angle for higher sensitivity in potential rollback scenarios.

Abstract: A ball-planetary continuously variable transmission (CVT) capable of stable control in forward and reverse rotation over a range of speed ratios including underdrive and overdrive is provided. Imparting a skew angle (zeta) causes unbalanced forces that change the tilt angle (gamma), resulting in a change in speed ratio of the CVT. Angularly orientating a control system of the CVT with a positive offset angle (psi) configures the CVT for operation in a first direction of rotation or angularly orientating the control system with a negative offset angle (psi) configures the CVT for operation in a reverse direction of rotation. A control system for configuring the offset angle (psi) may lead or trail the planets. The control system may configure a larger offset angle for more stable control or may configure a smaller offset angle for higher sensitivity in potential rollback scenarios.

Abstract: Inventive embodiments are directed to components, subassemblies, systems, and/or methods for continuously variable transmissions (CVT). In one embodiment, a control system is adapted to facilitate a change in the ratio of a CVT. In another embodiment, a control system includes a stator plate configured to have a plurality of radially offset slots. Various inventive traction planet assemblies and stator plates can be used to facilitate shifting the ratio of a CVT. In some embodiments, the traction planet assemblies include planet axles configured to cooperate with the stator plate. In one embodiment, the stator plate is configured to rotate and apply a skew condition to each of the planet axles. In some embodiments, a stator driver is operably coupled to the stator plate. Embodiments of a traction sun are adapted to cooperate with other components of the CVT to support operation and/or functionality of the CVT. Among other things, shift control interfaces for a CVT are disclosed.

Abstract: Traction planets and traction rings can be operationally coupled to a planetary gearset to provide a continuously variable transmission (CVT). The CVT can be used in a bicycle. In one embodiment, the CVT is mounted on the frame of the bicycle at a location forward of the rear wheel hub of the bicycle. In one embodiment, the CVT is mounted on and supported by members of the bicycle frame such that the CVT is coaxial with the crankshaft of the bicycle. The crankshaft is configured to drive elements of the planetary gearset, which are configured to operationally drive the traction rings and the traction planets. Inventive component and subassemblies for such a CVT are disclosed. A shifting mechanism includes a plurality of pivot arms arranged to pivot about the centers of the traction planets as a shift pin hub moves axially.

Abstract: Inventive embodiments are directed to components, subassemblies, systems, and/or methods for continuously variable transmissions (CVT). In one embodiment, a main axle is adapted to receive a shift rod that cooperates with a shift rod nut to actuate a ratio change in a CVT. In another embodiment, an axial force generating mechanism can include a torsion spring, a traction ring adapted to receive the torsion spring, and a roller cage retainer configured to cooperate with the traction ring to house the torsion spring. Various inventive idler-and-shift-cam assemblies can be used to facilitate shifting the ratio of a CVT. Embodiments of a hub shell and a hub cover are adapted to house components of a CVT and, in some embodiments, to cooperate with other components of the CVT to support operation and/or functionality of the CVT. Among other things, shift control interfaces and braking features for a CVT are disclosed.

Abstract: Components, subassemblies, systems, and/or methods for improving the performance and increasing the life of continuously variable transmissions (CVT). A first stator may be formed with an outer diameter greater than an outer diameter of a second stator. A stator may have radial slots formed to extend farther radially inward than slots on the other stator. The larger outer diameter of a stator or the formation of guide slots on a first stator extending farther radially inward of guide slots on a second stator may prevent egress of a planet axle from a radial slot, increase range of the CVT, allow for larger tolerances to reduce losses, and other advantages, Slots on a timing plate may be formed having a width greater than a width of guide slots formed on either stator to allow the stators to control adjustments while the timing plate avoids runaway axles. The shape, including junction between surfaces on a timing plate or stator may also prevent an axle from egressing.

Abstract: A continuously variable transmission (CVT) having a main shaft configured to support and position various components of the CVT. Shift cam discs cooperate with ball-leg assemblies to shift the transmission ration of the CVT. Load cam discs, a torsion disc, rolling elements, and a hub cap shell are configured to generate axial force, transmit torque, and manage reaction forces. In one embodiment, a splined input shaft and a torsion disc having a splined bore cooperate to input torque into the variator of the CVT. Among other things, various ball axles, axle-ball combinations, and reaction force grounding configurations are disclosed. In one embodiment, a CVT having axial force generation means at both the input and output elements is disclosed.

Abstract: A continuously variable transmission (CVT) can be used in concert with an electric motor to facilitate power assistance to a rider in a bicycle. In some embodiments, the CVT and motor is mounted on the frame of the bicycle at a location forward of the rear wheel hub of the bicycle. In some embodiments, the CVT is mounted on and supported by members of the bicycle frame such that the CVT is coaxial with the crankshaft of the bicycle. The crankshaft is configured to drive elements of the CVT, which are configured to operationally drive the traction rings and the traction planets. In some embodiments, the motor is configured to drive elements of the CVT. In other embodiments, the motor is configured to drive the crankshaft. Inventive component and subassemblies for such a CVT are disclosed.

Abstract: Continuously variable transmissions (CVTs) having a plurality of balls, each ball having a bore through which a ball axle passes, are provided. In some aspects, the CVTs include first and second rings on either side and in contact with the plurality of balls, and an idler assembly including an idler having a non-uniform outer diameter. The profile of the idler ensures lubricant flows to a largest diameter of the non-uniform outer diameter, and lubricant sprays off the largest diameter to lubricate one or more components of the CVT. A lubrication system may include a scraper configured to remove lubricant that accumulates in an interior of the CVT.

Abstract: Inventive embodiments are directed to components, subassemblies, systems, and/or methods for continuously variable transmissions (CVT). In one embodiment, a main axle is adapted to receive a carrier assembly to facilitate the support of components in a CVT. In another embodiment, a carrier includes a stator support member and a stator interfacial member. In some embodiments, the stator interfacial member is configured to interact with planet subassemblies of a CVT. Various inventive planet subassemblies and idler assemblies can be used to facilitate shifting the ratio of a CVT. In some embodiments, the planet subassemblies include legs configured to have a sliding interface with a carrier assembly. Embodiments of a hub shell, a hub cover are adapted to house components of a CVT and, in some embodiments, to cooperate with other components of the CVT to support operation and/or functionality of the CVT. Among other things, shift control interfaces and braking features for a CVT are disclosed.

Abstract: A continuously variable transmission (CVT) having a main shaft configured to support and position various components of the CVT. Shift cam discs cooperate with ball-leg assemblies to shift the transmission ration of the CVT. Load cam discs, a torsion disc, rolling elements, and a hub cap shell are configured to generate axial force, transmit torque, and manage reaction forces. In one embodiment, a splined input shaft and a torsion disc having a splined bore cooperate to input torque into the variator of the CVT. Among other things, various ball axles, axle-ball combinations, and reaction force grounding configurations are disclosed. In one embodiment, a CVT having axial force generation means at both the input and output elements is disclosed.

Abstract: Inventive embodiments are directed to components, subassemblies, systems, and/or methods for continuously variable transmissions (CVT). In one embodiment, a control system is adapted to facilitate a change in the ratio of a CVT. In another embodiment, a control system includes a stator plate configured to have a plurality of radially offset slots. Various inventive traction planet assemblies and stator plates can be used to facilitate shifting the ratio of a CVT. In some embodiments, the traction planet assemblies include planet axles configured to cooperate with the stator plate. In one embodiment, the stator plate is configured to rotate and apply a skew condition to each of the planet axles. In some embodiments, a stator driver is operably coupled to the stator plate. Embodiments of a traction sun are adapted to cooperate with other components of the CVT to support operation and/or functionality of the CVT. Among other things, shift control interfaces for a CVT are disclosed.

Abstract: A continuously variable transmissions (CVT), includes a main axle adapted to receive a shift rod that cooperates with a shift rod nut to actuate a ratio change in a CVT. An axial force generating mechanism can include a torsion spring, a traction ring adapted to receive the torsion spring, and a roller cage retainer configured to cooperate with the traction ring to house the torsion spring. Power roller-leg assemblies can be used to facilitate shifting the ratio of a CVT. A hub shell and a hub cover are adapted to house components of a CVT and, in some embodiments, to cooperate with other components of the CVT to support operation and/or functionality of the CVT. Among other things, shift control interfaces and braking features for a CVT are disclosed.

Abstract: Inventive embodiments are directed to components, subassemblies, systems, and/or methods for continuously variable transmissions (CVT). In one embodiment, a control system is adapted to facilitate a change in the ratio of a CVT. In another embodiment, a control system includes a stator plate configured to have a plurality of radially offset slots. Various inventive traction planet assemblies and stator plates can be used to facilitate shifting the ratio of a CVT. In some embodiments, the traction planet assemblies include planet axles configured to cooperate with the stator plate. In one embodiment, the stator plate is configured to rotate and apply a skew condition to each of the planet axles. In some embodiments, a stator driver is operably coupled to the stator plate. Embodiments of a traction sun are adapted to cooperate with other components of the CVT to support operation and/or functionality of the CVT. Among other things, shift control interfaces for a CVT are disclosed.

Abstract: Traction planets and traction rings can be operationally coupled to a planetary gearset to provide a continuously variable transmission (CVT). The CVT can be used in a bicycle. In one embodiment, the CVT is mounted on the frame of the bicycle at a location forward of the rear wheel hub of the bicycle. In one embodiment, the CVT is mounted on and supported by members of the bicycle frame such that the CVT is coaxial with the crankshaft of the bicycle. The crankshaft is configured to drive elements of the planetary gearset, which are configured to operationally drive the traction rings and the traction planets. Inventive component and subassemblies for such a CVT are disclosed. A shifting mechanism includes a plurality of pivot arms arranged to pivot about the centers of the traction planets as a shift pin hub moves axially.