Continuously variable transmission

• US 9,732,848 B2
• Filed: 05/29/2015
• Issued: 08/15/2017
• Est. Priority Date: 02/28/2003
• Status: Expired due to Fees

• Current Assignee: Fallbrook Intellectual Property Company LLC (Fallbrook Technologies Incorporated)
• Original Assignee: Fallbrook Intellectual Property Company LLC (Fallbrook Technologies Incorporated)
• Inventors: Miller, Donald C., Allen, David J., Smithson, Robert A.
• Primary Examiner(s): Wright, Dirk
• Application Number:
  US14/725,305
• Publication Number:
  US 20150260284A1
• Time in Patent Office: 809 Days
• Field of Search: None
• 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 method for transferring power through a variable speed transmission having a plurality of balls, each ball having a tiltable axle about which it rotates, the method comprising:

receiving a power input by a rotatable input disc positioned adjacent to the balls and in contact with each of the balls;

determining a desired power output for the variable speed transmission;

adjusting a tilt angle for the plurality of balls, wherein the tilt angle is based on one of a desired speed ratio or torque ratio corresponding to the desired power output; and

routing the received power through one of an output disc or a rotatable idler, wherein the output disc is positioned adjacent to the balls opposite the input disc and in contact with each of the balls, wherein the idler is positioned radially inward of and in contact with each of the balls, and wherein the idler is coupled to an idler shaft adapted to receive a power output from the idler and transmit the power output out of the transmission.

2. The method of claim 1, wherein power is transferred via a cage that is rotatable about a longitudinal axis of the variable speed transmission.

3. The method of claim 1, further comprising generating an axial force that increases the traction between the plurality of balls and at least one of the input disc and the output disc.

4. The method of claim 3, wherein an amount of axial force is a function of a transmission ratio of the transmission.

5. The method of claim 1, wherein the variable speed transmission further comprises a planetary gear set, the method further comprising:

determining a first power path through the planetary gear set; and

determining a second power path through the plurality of balls.

6. The method of claim 5, wherein the second power path comprises two power paths.

7. The method of claim 1, wherein a pair of legs is coupled to an axle of each ball, wherein radial movement of one or both legs controls the tilt angle of that ball.

8. The method of claim 1, further comprising disengaging the variable speed transmission when the output rotation is greater than the input rotation.

9. The method of claim 8, wherein disengagement occurs when input rotation ceases and the output disc continues to be rotated.

10. The method of claim 9, further comprising engaging the variable speed transmission when input rotation resumes.

11. A method for transferring power through a variable speed transmission having a plurality of balls, an input disc, an output disc, an idler and a cage, each ball having a tiltable axle about which it rotates, the method comprising:

receiving a power input by the input disc or the cage, wherein the input disc is positioned adjacent to the balls and in contact with each of the balls;

determining a desired power output for the variable speed transmission;

adjusting a tilt angle for the plurality of balls, wherein the tilt angle is based on one of a desired speed ratio or torque ratio corresponding to the desired power output; and

routing the received power through the output disc or the idler, wherein the output disc is positioned adjacent to the balls opposite the input disc and in contact with each of the balls, wherein the idler is positioned radially inward of and in contact with each of the balls, and wherein the idler is coupled to an idler shaft adapted to receive a power output from the idler and transmit the power output out of the transmission.

12. The method of claim 11, wherein power is input through the input disc and the cage.

13. The method of claim 12, wherein the input disc and the cage rotate at different speeds.

14. The method of claim 11, further comprising a planetary gear set, wherein the method comprises transmitting power through the input disc and a first gear of the planetary gear set to form a parallel power path.

15. The method of claim 14, wherein a first power path routes power through one of a sun, carrier or ring of the planetary gear set and a second power path routes power through another one of the sun, carrier or ring.