Continuously variable transmission

• US 7,731,615 B2
• Filed: 02/08/2008
• Issued: 06/08/2010
• Est. Priority Date: 02/28/2003
• Status: Expired due to Fees

• Current Assignee: Enviolo BV
• Original Assignee: Fallbrook Technologies Incorporated
• Inventors: Miller, Donald C, Allen, David J, Smithson, Robert A.
• Primary Examiner(s): Wright; Dirk
• Application Number:
  US12/028,715
• Publication Number:
  US 20080125282A1
• Time in Patent Office: 851 Days
• Field of Search: 475/189
• US Class Current: 475/189
• 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 first 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 first rotatable disc;

a second rotatable 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, wherein the idler is nonrotatable relative to the longitudinal axis; and

a cage operably coupled to the plurality of tiltable balls, the cage adapted to rotate freely without transferring power.

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

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

4. The transmission of claim 3, further comprising a plurality of rollers adapted to couple operably the plurality of balls axles to the cage.

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

providing a transmission comprising;

a first 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 first rotatable disc;

a second rotatable 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, wherein the idler is nonrotatable relative to the longitudinal axis; and

a cage operably coupled to the plurality of tiltable balls, the cage adapted to rotate freely without transferring power;

operably coupling the first rotatable disc to a power input; and

operably coupling the second rotatable disc to a load.

6. The method of claim 5, further comprising delivering power from the first rotatable disc to the tiltable balls via a plurality of contacts between the first rotatable disc and the tiltable balls.

7. The method of claim 6, further comprising delivering power from the tiltable balls to the second rotatable disc via a plurality of contacts between the tiltable balls and the second rotatable disc.

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

8. A transmission comprising:

a first 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 first rotatable disc;

a second rotatable disc mounted coaxially about the longitudinal axis and in contact with the plurality of tiltable balls, wherein the second rotatable disc is adapted to rotate freely without transferring power;

an idler placed radially inward of, and in contact with, the plurality of tiltable balls, wherein the idler is nonrotatable relative to the longitudinal axis; and

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

9. The transmission of claim 8, wherein the first rotatable disc is adapted to receive a power input, and wherein the cage is adapted to provide a power output.

11. The transmission of claim 8, 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.

12. The transmission of claim 11, further comprising a plurality of rollers adapted to couple operably the plurality of ball axles to the cage.

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

providing a transmission comprising;

a first 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 first rotatable disc;

a second rotatable disc mounted coaxially about the longitudinal axis and in contact with the plurality of tiltable balls, wherein the second rotatable disc is adapted to rotate freely without transferring power;

an idler placed radially inward of, and in contact with, the plurality of tiltable balls, wherein the idler is nonrotatable relative to the longitudinal axis; and

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

operably coupling the first rotatable disc to a power input; and

operably coupling the rotatable cage to a load.

14. The method of claim 13, further comprising delivering power from the first rotatable disc to the tiltable balls.

15. The method of claim 14, 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 balls to the cage.

16. The method of claim 15, further comprising delivering power from the tiltable balls to the rotatable cage via at least the ball axles.

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

providing a transmission comprising;

a first 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 first rotatable disc;

a second rotatable disc mounted coaxially about the longitudinal axis and in contact with the plurality of tiltable balls, wherein the second rotatable disc is adapted to rotate freely without transferring power;

an idler placed radially inward of, and in contact with, the plurality of tiltable balls, wherein the idler is nonrotatable relative to the longitudinal axis; and

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

coupling the first rotatable disc to a load; and

coupling the rotatable cage to a power input.

18. The method of claim 17, further comprising providing a plurality of ball axles, each ball 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.

19. The method of claim 18, further comprising delivering power from the rotatable cage to the tiltable balls via the ball axles.

20. The method of claim 19, further comprising delivering power from the tiltable balls to the first rotatable disc.