Continuously variable transmission

Patent metadata

Field	Value
Publication number	US-10704657-B2
Application number	US-201815904831-A
Country	US
Kind code	B2
Filing date	Feb 26, 2018
Priority date	Aug 26, 2008
Publication date	Jul 7, 2020
Grant date	Jul 7, 2020

Abstract

Components, subassemblies, systems, and/or methods for continuously variable transmissions (CVT) having a control system adapted to facilitate a change in the ratio of a CVT are described. In one embodiment, a control system includes a stator plate configured to have a plurality of radially offset slots. Various 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.

First claim

What we claim is:

1. A continuously variable transmission (CVT) comprising a main shaft defining a main drive axis and a plurality of spherical traction planets arranged around the main drive axis, each traction planet comprising a planet axle defining a tiltable axis of rotation, the CVT comprising:
a first stator plate, mounted coaxially about the main shaft, comprising a plurality of radially offset slots arranged angularly in a first plane about a center of the first stator plate coaxial with the main drive axis of the CVT, wherein a first end of each planet axle is positioned in a radially offset slot; and
a second stator plate, mounted coaxially about the main shaft, comprising a plurality of radial slots, the plurality of radial slots arranged angularly about a center of the second stator plate coaxial with the main drive axis of the CVT wherein a second end of each planet axle is positioned in a radial slot, and wherein the first stator plate is configured for rotation relative to the second stator plate.

2. The CVT of claim 1 , wherein the second stator plate is non-rotatable about the main drive axis of the CVT.

3. The CVT of claim 1 , wherein each radially offset slot has a curved profile in a second plane perpendicular to the first plane defined by the first stator plate.

4. The CVT of claim 3 , wherein the first stator plate is formed with a clearance cut.

5. The CVT of claim 4 , further comprising a shift stop extension arranged about the center of the first stator plate.

6. The CVT of claim 5 , wherein the shift stop extension is located radially inward of the radially offset slots.

7. The CVT of claim 5 , wherein the shift stop extension is located radially outward of the radially offset slots.

8. The CVT of claim 1 , further comprising a control system configured to rotate the first stator plate relative to the second stator plate to an angular displacement (β) to induce a non-zero skew angle (ζ) to tilt the axles of the traction planets to a unique tilt angle (γ) to control an operating condition of the CVT.

9. The CVT of claim 8 , wherein the operating condition is a speed ratio.

10. The CVT of claim 8 , wherein the control system comprises a microprocessor communicatively coupled to a look-up table used to convert a value of angular displacement to an actuator command signal.

11. The CVT of claim 10 , wherein the actuator command signal comprises a voltage or current.

12. The CVT of claim 10 , wherein the microprocessor is configured to control the CVT using an open loop scheme.

13. A method of controlling a continuously variable transmission (CVT) comprising a main shaft defining a main drive axis and a plurality of spherical traction planets arranged around the main drive axis, each traction planet comprising a planet axle defining a tiltable axis of rotation, a first end of each planet axle being positioned in a radially offset slot in a first stator, mounted coaxially about the main axis, and a second end of each planet axle being positioned in a radial slot in a second stator, mounted coaxially about the main axis, the method comprising:
rotating the first stator relative to the second stator to an angular displacement (β) to induce a non-zero skew angle (ζ) to tilt the axles of the traction planets to a unique tilt angle (γ).

14. The method of claim 13 , wherein a control system including a microprocessor performs:
receiving a desired speed ratio (SR) set point for the CVT;
determining the angular displacement for the CVT; and
determining, from a look-up table, an actuator command signal based on the determined angular displacement.

15. The method of claim 14 , further comprising determining the actual SR for the CVT.

16. The method of claim 15 , wherein measuring the actual SR of the CVT comprises measuring a speed of an input component and an output component of the CVT.

17. The method of claim 15 , wherein measuring the actual SR of the CVT comprises measuring a tilt angle of a planet axis of rotation.

18. The method of claim 15 , wherein measuring the actual SR of the CVT comprises measuring a torque of one or more of an input component and an output component.

19. The method of claim 15 , performed as an open loop process.

Assignees

• Fallbrook Ip Co Llc

Inventors

• Thomassy Fernand A

Classifications

• F16H15/28 Primary

  with external friction surface · CPC title

• F16H15/52

  in which a member of uniform effective diameter mounted on a shaft may co-operate with different parts of another member · CPC title

• F16H15/503 Primary

  in which two members co-operate by means of balls or rollers of uniform effective diameter, not mounted on shafts · CPC title

• Y10T29/49464

  Assembling of gear into force transmitting device · CPC title

• F16H55/32

  Friction members · CPC title