Continuously variable transmission

• US 7,727,108 B2
• Filed: 02/08/2008
• Issued: 06/01/2010
• Est. Priority Date: 02/28/2003
• Status: Active Grant

• Current Assignee: Fallbrook Intellectual Property Company LLC (Fallbrook Technologies Incorporated)
• Original Assignee: Fallbrook Technologies Incorporated
• Inventors: Miller, Donald C, Allen, David J, Smithson, Robert A.
• Primary Examiner(s): Wright; Dirk
• Application Number:
  US12/028,734
• Publication Number:
  US 20080132377A1
• Time in Patent Office: 844 Days
• Field of Search: None
• US Class Current: 476/38
• CPC Class Codes: B62M 11/04 of changeable ratio
• CPC Class Codes: B62M 11/14 with planetary gears
• CPC Class Codes: B62M 9/08 involving eccentrically- mounted or elliptically-shaped driving or driven wheel; with expansible driving or driven wheel
• CPC Class Codes: F16H 15/28 with external friction surface
• CPC Class Codes: F16H 15/40 in which two members co-operative by means of balls, or rollers of uniform effective diameter, not mounted on shafts
• CPC Class Codes: F16H 15/50 Gearings providing a continuous range of gear ratios
• CPC Class Codes: F16H 15/503 in which two members co-operate by means of balls or rollers of uniform effective diameter, not mounted on shafts
• CPC Class Codes: F16H 15/52 in which a member of uniform effective diameter mounted on a shaft may co-operate with different parts of another member
• CPC Class Codes: F16H 2037/088 Power split variators with summing differentials, with the input of the CVT connected or connectable to the input shaft
• CPC Class Codes: F16H 2037/101 Power split variators with one differential at each end of the CVT
• CPC Class Codes: F16H 37/084 at least one power path being a continuously variable transmission, i.e. CVT
• CPC Class Codes: F16H 37/0853 CVT using friction between rotary members having a first member of uniform effective diameter cooperating with different parts of a second member
• CPC Class Codes: F16H 37/086 CVT using two coaxial friction members cooperating with at least one intermediate friction member
• CPC Class Codes: F16H 61/6649 characterised by the means for controlling the torque transmitting capability of the gearing
• CPC Class Codes: F16H 63/067 mechanical actuating means
• CPC Class Codes: Y10T 29/49464 Assembling of gear into force transmitting device
• CPC Class Codes: Y10T 408/65 Means to drive tool

Abstract

A variable speed transmission having a plurality of tilting balls and opposing input and output discs is illustrated and described that provides an infinite number of speed combinations over its transmission ratio range. The use of a planetary gear set allows minimum speeds to be in reverse and the unique geometry of the transmission allows all of the power paths to be coaxial, thereby reducing overall size and complexity of the transmission in comparison to transmissions achieving similar transmission ratio ranges.

Claims

1. A transmission comprising:

a rotatable disc mounted coaxially about a longitudinal axis of the transmission;

a plurality of tiltable balls placed angularly about the longitudinal axis and in contact with the rotatable disc;

a nonrotatable disc mounted coaxially about the longitudinal axis and in contact with the plurality of tiltable balls;

a rotatable idler placed radially inward of, and in contact with, the plurality of tiltable balls, the idler adapted to rotate freely without transferring power; and

a rotatable cage operably coupled to the plurality of tiltable balls.

2. The transmission of claim 1, wherein the rotatable disc is adapted to receive a power input, and wherein the rotatable cage is adapted to provide a power output.

3. The transmission of claim 1, wherein the rotatable disc is adapted to provide a power output, and wherein the rotatable cage is adapted to receive a power input.

4. The transmission of claim 1, further comprising a plurality of ball axles, each axle placed in a respective bore of each ball, and wherein the plurality of ball axles operably couples the plurality of tiltable balls to the cage.

5. The transmission of claim 4, further comprising a plurality of rollers adapted to couple operably the plurality of ball axles to the cage.

6. The transmission of claim 1, further comprising an input shaft operably coupled to the first rotatable disc, wherein the input shaft is arranged along the longitudinal axis of the transmission.

7. The transmission of claim 6, wherein the input shaft is adapted to receive a power input, and wherein the rotatable cage is adapted to provide a power output.

8. A method of transferring mechanical power, the method comprising the steps of:

providing a transmission comprising;

a rotatable disc mounted coaxially about a longitudinal axis of the transmission;

a plurality of tiltable balls placed angularly about the longitudinal axis and in contact with the rotatable disc;

a nonrotatable disc mounted coaxially about the longitudinal axis and in contact with the plurality of tiltable balls;

an idler placed radially inward of, and in contact with, the plurality of tiltable balls, the idler adapted to rotate freely without transferring power; and

a rotatable cage operably coupled to the plurality of tiltable balls;

coupling the rotatable disc to a power input; and

coupling the rotatable cage to a load.

9. The method of claim 8, further comprising providing a plurality of ball axles, each ball axle placed in a respective bore of each tiltable ball, and wherein the plurality of ball axles operably couples the plurality of tiltable balls to the cage.

10. The method of claim 9, further comprising providing a plurality of rollers adapted to couple operably the plurality of ball axles to the cage.

11. The method of claim 8, further comprising providing an input shaft arranged along the longitudinal axis of the transmission, the input shaft operably coupled to the first rotatable disc.

12. A method of transferring mechanical power, the method comprising the steps of:

providing a transmission comprising;

a rotatable disc mounted coaxially about a longitudinal axis of the transmission;

a plurality of tiltable balls placed angularly about the longitudinal axis and in contact with the rotatable disc;

a nonrotatable disc mounted coaxially about the longitudinal axis and in contact with the plurality of tiltable balls;

an idler placed radially inward of, and in contact with, the plurality of tiltable balls, the idler adapted to rotate freely without transferring power; and

a rotatable cage operably coupled to the plurality of tiltable balls;

coupling the rotatable disc to a load; and

coupling the rotatable cage to a power input.

13. The method of claim 12, further comprising providing an input shaft arranged along the longitudinal axis of the transmission, the input shaft coupled to the first rotatably disc.

14. The method of claim 12, further comprising providing an output shaft arranged along the longitudinal axis of the transmission, the output shaft coupled to the cage.

15. A transmission comprising:

a rotatable disc mounted coaxially about a longitudinal axis of the transmission, the rotatable disc adapted to rotate freely without transferring power;

a plurality of tiltable balls placed angularly about the longitudinal axis and in contact with the rotatable disc;

a nonrotatable disc mounted coaxially about the longitudinal axis and in contact with the plurality of tiltable balls;

a rotatable idler placed radially inward of, and in contact with, the plurality of tiltable balls; and

a rotatable cage operably coupled to the plurality of tiltable balls.

16. The transmission of claim 15, wherein the rotatable cage is adapted to receive a power input, and wherein the rotatable idler is adapted to provide a power output.

17. The transmission of claim 15, wherein the rotatable cage is adapted to provide power output, and wherein the rotatable idler is adapted to receive a power input.

18. The transmission of claim 15, further comprising a plurality of ball axles, each ball axle placed in a respective bore of each tiltable ball, and wherein the plurality of ball axles operably couples the plurality of tiltable balls to the cage.

19. A method of transferring mechanical power, the method comprising the steps of:

providing a transmission comprising;

a rotatable disc mounted coaxially about a longitudinal axis of the transmission, the rotatable disc adapted to rotate freely without transferring power;

a plurality of tiltable balls placed angularly about the longitudinal axis and in contact with the rotatable disc;

a nonrotatable disc mounted coaxially about the longitudinal axis and in contact with the plurality of tiltable balls;

a rotatable idler placed radially inward of, and in contact with, the plurality of tiltable balls; and

a rotatable cage operably coupled to the plurality of tiltable balls;

coupling the rotatable cage to a power input; and

coupling the rotatable idler to a load.

20. A method of transferring mechanical power, the method comprising the steps of:

providing a transmission comprising;

a rotatable disc mounted coaxially about a longitudinal axis of the transmission, the rotatable disc adapted to rotate freely without transferring power;

a plurality of tiltable balls placed angularly about the longitudinal axis and in contact with the rotatable disc;

a nonrotatable disc mounted coaxially about the longitudinal axis and in contact with the plurality of tiltable balls;

a rotatable idler placed radially inward of, and in contact with, the plurality of tiltable balls; and

a rotatable cage operably coupled to the plurality of tiltable balls;

coupling the rotatable cage to a load; and

coupling the rotatable idler to a power input.