CONTINUOUSLY VARIABLE TRANSMISSION

• US 20180066754A1
• Filed: 08/11/2017
• Published: 03/08/2018
• Est. Priority Date: 02/28/2003
• Status: Active Grant

• 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.
• Granted Patent: US 10,428,939 B2
• Time in Patent Office: Days
• 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 variable speed transmission, comprising:

a main axle defining a longitudinal axis;

a plurality of balls arranged angularly around the main axle, each ball having a tiltable axle defining an axis about which it rotates;

an input disc positioned adjacent to the balls and in contact with each of the balls;

an output disc positioned adjacent to the balls opposite the input disc and in contact with each of the balls;

a rotatable idler having a constant outside diameter and positioned radially inward of and in contact with the plurality of balls; and

an input stator comprising a first set of stator curves and an output stator comprising a second set of stator curves, wherein each of the input stator and the output stator has a first side facing toward the plurality of balls and a second side facing away from the plurality of balls, and wherein the first set of stator curves are offset from the second set of stator curves.

2. The variable speed transmission of claim 1, wherein the first side comprises a concave face.

3. The variable speed transmission of claim 1, wherein the first side comprises a convex face.

4. The variable speed transmission of claim 1, wherein the stator curves are integral with the input stator or the output stator.

5. The variable speed transmission of claim 1, further comprising a plurality of spacers coupled to the input stator and the output stator, wherein the input stator, the output stator, and the plurality of spacers form a cage.

6. The variable speed transmission of claim 1, wherein a tilt angle of the plurality of balls is generated by moving one end of each tiltable axle radially inward or radially outward.

7. The variable speed transmission of claim 6, wherein each ball is coupled to two legs, and wherein moving one end of each tiltable axle comprises moving at least one leg radially outward or radially inward.

8. The variable speed transmission of claim 1, wherein one of the input stator and the output stator is non-rotatable relative to the main axle.

9. A drivetrain comprising:

a prime mover;

a variable speed transmission, comprising

a main axle defining a longitudinal axis,

a plurality of balls arranged angularly around the main axle, each ball having a tiltable axle defining an axis about which it rotates,

an input disc positioned adjacent to the balls and in contact with each of the balls,

an output disc positioned adjacent to the balls opposite the input disc and in contact with each of the balls,

a rotatable idler having a constant outside diameter and positioned radially inward of and in contact with the plurality of balls, and

an input stator comprising a first set of stator curves and an output stator comprising a second set of stator curves, wherein each of the input stator and the output stator has a first side facing toward the plurality of balls and a second side facing away from the plurality of balls, and wherein the first set of stator curves are offset from the second set of stator curves; and

a disengagement mechanism configured to decouple the variable speed transmission from the prime mover.

10. The drivetrain of claim 9, further comprising a plurality of spacers coupled to the input stator and the output stator, wherein the input stator, the output stator, and the plurality of spacers form a cage.

11. The drivetrain of claim 9, wherein one of the input stator and the output stator is non-rotatable relative to the main axle.

12. The drivetrain of claim 9, wherein the disengagement mechanism comprises a ratchet.

13. A method for operating a drivetrain comprising a prime mover and a variable speed transmission, the variable speed transmission comprising a main axle defining a longitudinal axis, a plurality of balls arranged angularly around the main axle, each ball having a tiltable axle defining an axis about which it rotates, an input disc positioned adjacent to the balls and in contact with each of the balls, an output disc positioned adjacent to the balls opposite the input disc and in contact with each of the balls, a rotatable idler having a constant outside diameter and positioned radially inward of and in contact with the plurality of balls, and an input stator comprising a first set of stator curves and an output stator comprising a second set of stator curves, wherein the first set of stator curves are offset from the second set of stator curves, and a disengagement mechanism configured to decouple the variable speed transmission from the prime mover, the method comprising:

when the variable speed transmission is engaged with the prime mover and rotation of the plurality of balls is caused by a rotation of the input disc, changing a tilt angle of the plurality of balls to change an output speed of the output disc; and

when the variable speed transmission is disengaged from the prime mover and rotation of the plurality of balls is caused by a rotation of the output disc, changing a tilt angle of the plurality of balls to a speed ratio based on the output speed of the output disc.

14. The method of claim 13, further comprising disengaging the variable speed transmission from the prime mover.

15. The method of claim 14, wherein rotation of the output disc is caused by a rotation of an output rotating mechanism.

16. The method of claim 15, wherein the output rotating mechanism comprises a drivetrain or a wheel.

17. The method of claim 14, wherein disengaging the variable speed transmission from the prime mover comprises rotating the input disc in a first direction to move the input disc up a screw, and wherein engaging the variable speed transmission to the prime mover comprises rotating the input disc in a second direction to move the input disc down the screw.

18. The method of claim 13, wherein the disengagement mechanism comprises a ratchet.