Continuously variable transmission

A method of facilitating control of the speed ratio of a continuously variable transmission (CVT), the method comprising the steps of:

• providing a plurality of traction planets;
• providing each of the traction planets with a planet axle, each traction planet configured to rotate about a respective planet axle;
• providing a first carrier plate configured to engage a first end of each of the planet axles, the first carrier plate mounted along a longitudinal axis of the CVT;
• providing a second carrier plate configured to engage a second end of each of the planet axles, the second carrier plate mounted coaxially with the first carrier plate;
• and
• arranging the first carrier plate relative to the second carrier plate such that during operation of the CVT the first carrier plate can be rotated, about the longitudinal axis, relative to the second carrier plate.

A transmission comprising:

• a plurality of traction planets arranged angularly about a longitudinal axis of the transmission;
• a plurality of planet axles, each planet axle operably coupled to each traction planet, each planet axle defining a tiltable axis of rotation for each traction planet, each planet axle configured for angular displacement in first and second planes;
• a first carrier plate operably coupled to a first end of each planet axle, the first carrier plate mounted about the longitudinal axis;
• a second carrier plate operably coupled to a second end of each planet axle, the second carrier plate mounted about the longitudinal axis;
• and
• wherein the first and second carrier plates are configured to rotate, about the longitudinal axis, relative to each other.

A method of controlling a continuously variable transmission (CVT) having a plurality of traction planets, each traction planet having a planet axle about which the traction planet rotates, the method comprising the steps of:

• providing a control reference indicative of a desired operating condition of the CVT;
• determining a skew angle based at least in part on the desired operating condition of the CVT;
• and
• applying the skew angle to each of the planet axles.

A method of controlling a continuously variable transmission (CVT) having a plurality of traction planets with tiltable axes of rotation, the method comprising the steps of:

• providing a control reference indicative of a desired operating condition of the CVT;
• sensing a current operating condition of the CVT;
• comparing the desired operating condition with the current operating condition thereby generating a control error;
• and
• imparting a skew angle to each of the tiltable axes, the skew angle based at least in part on the control error.

A control system for a transmission having a traction sun and a plurality of traction planets each having a tiltable axis of rotation, the control system comprising:

• a control reference source configured to provide a control reference indicative of a desired operating condition of the transmission;
• a feedback source configured to provide a feedback indicative of a current operating condition of the transmission;
• a sun position locker operably coupled to the traction sun, the sun position locker configured to selectively hold an axial position of the traction sun;
• a skew angle coordinator operably coupled to the traction planets;
• and
• a decision process module configured to compare the control reference to the feedback, the decision process module configured to generate a signal based at least in part on the comparison, the signal configured to be passed to the sun position locker and to the skew angle coordinator.

A control system for a transmission having a traction sun and a plurality of traction planets operably coupled to a carrier plate and to the traction sun, the control system comprising:

• a control reference nut mounted coaxially with a longitudinal axis of the CVT;
• a feedback cam operably coupled to the control reference nut and to the traction sun, the feedback cam positioned coaxially with the control reference nut, wherein the carrier plate is positioned coaxially with the feedback cam;
• and
• a skew cam coupled to the feedback cam and to the carrier plate, the skew cam configured to rotate the carrier plate about the longitudinal axis.

A neutralizer assembly for a continuously variable transmission having a skew-based control system, the neutralizer assembly comprising:

• a first resistance member configured to generate a force in a first axial direction;
• a second resistance member configured to generate a force in a second axial direction;
• and
• a translating resistance cap operably coupled to the skew-based control system, the translating resistance cap configured to separately engage each of the first and the second resistance members.

A feedback cam for a skew-based control system, the feedback cam comprising:

• a generally elongated cylindrical body having a first end and a second end;
• a bearing race located on the first end;
• a threaded portion located on the first end;
• and
• a splined portion located on the second end.

A skew cam for a continuously variable transmission (CVT) having a skew-based control system, the skew cam comprising:

• a generally elongated cylindrical body having a first end and a second end;
• a first threaded portion located in proximity to the first end;
• a second threaded portion located in proximity to the second end;
• and
• wherein the first threaded portion has a lead that is smaller than a lead of the second threaded portion.

A carrier plate for a continuously variable transmission (CVT) having a skew-based control system and a plurality of traction planets, the carrier plate comprising:

• a generally cylindrical plate;
• a plurality of concave surfaces formed on a face of the cylindrical plate, the concave surfaces adapted to operably couple to each of the traction planets;
• a threaded central bore configured to operably couple to the skew-based control system;
• and
• a reaction face coaxial with the central bore, the reaction face configured to operably couple to the skew-based control system.

A leg assembly for a continuously variable transmission (CVT) having a skew-based control system, the leg assembly comprising:

• a leg comprising:
• an elongated body having a first end and a second end;
• a first bore formed on the first end;
• a second bore formed in proximity to the first end, the second bore having first and second clearance bores, the second bore being substantially perpendicular to the first bore;
• and
• a shift guide roller axle operably coupled to the second bore, the shift guide roller axle adapted to pivot in the second bore.

A leg for a continuously variable transmission (CVT) having a skew-based control system, the leg comprising:

• an elongated body having a first end and a second end;
• a first bore formed on the first end;
• a second bore formed in proximity to the first end, the second bore having first and second clearance bores, the second bore being substantially perpendicular to the first bore;
• and
• a third clearance bore formed between the first and second clearance bores, the third clearance bore configured to provide a pivot location for a shift guide roller axle of the CVT.

A transmission comprising:

• a longitudinal axis;
• a traction sun coaxial with the longitudinal axis, the traction sun configured to translate axially;
• first and second carrier plates coaxial with the longitudinal axis, wherein the traction sun is positioned between the first and second carrier plates;
• a planetary gear set operably coupled to a control reference input source;
• a feedback cam operably coupled to the planetary gear set and to the traction sun;
• a skew cam operably coupled to the planetary gear set and to the first carrier plate;
• first and second resistance members operably coupled to the skew cam;
• and
• wherein the first carrier is configured to be rotatable with respect to the second carrier plate.

A control reference assembly for a continuously variable transmission (CVT) having a skew-based control system, the control reference assembly comprising:

• a control reference nut;
• first and second resistance members coupled to the control reference nut;
• an intermediate reaction member coupled to the first and second resistance members, the intermediate reaction member located coaxially with, and radially inward of, the control reference nut;
• and
• wherein a rotation of the control reference nut in a first direction energizes the first resistance member, and wherein a rotation of the control reference nut in a second direction energizes the second resistance member.

A control reference assembly for a continuously variable transmission (CVT) having a skew-based control system, the control reference assembly comprising:

• a control reference nut;
• first and second resistance members coupled to the control reference nut;
• a pulley operably coupled to the control reference nut;
• first and second cables each coupled to the control reference nut and to the pulley;
• a spring retention member coupled to the pulley and to the first and second resistance members;
• and
• wherein a rotation of the control reference nut in a first direction unwinds the first cable from the pulley, and wherein a rotation of the control reference nut in a second direction unwinds the second cable from the pulley.

A transmission comprising:

• a carrier plate mounted coaxial with a longitudinal axis of the transmission;
• a plurality of traction planets arranged angularly about the longitudinal axis;
• a planet axle operably coupled to each traction planet, the planet axle defining a tiltable axis of rotation;
• a planet support trunnion coupled to a respective planet axle, the planet support trunnion having an eccentric skew cam configured to couple to the carrier plate;
• a sleeve coupled to each planet support trunnion, the sleeve configured to axially translate, the sleeve configured to rotate;
• and
• wherein a rotation of the sleeve imparts a skew angle to each of the planet axles.

A torque governor for a continuously variable transmission (CVT) having a plurality of traction planets with tiltable axes of rotation, the torque governor comprising:

• a carrier plate mounted coaxial with a longitudinal axis of the CVT;
• a shift cam operably coupled to the carrier plate, the shift cam having a threaded extension;
• a first reaction arm coupled to the shift cam, the first reaction arm operably coupled to the carrier plate, the first reaction arm coaxial with the longitudinal axis;
• a second reaction arm operably coupled to the first reaction arm;
• and
• wherein the first and second reaction arms are configured to rotate the carrier plate during operation of the CVT.