Continuously variable transmission

• US 6,949,049 B2
• Filed: 02/03/2004
• Issued: 09/27/2005
• Est. Priority Date: 04/26/2001
• Status: Expired due to Term

• Current Assignee: Fallbrook Intellectual Property Company LLC (Fallbrook Technologies Incorporated)
• Original Assignee: Fallbrook Technologies Incorporated
• Inventors: Allen, David John, Miller, Donald C.
• Primary Examiner(s): Fenstermacher, David M.
• Application Number:
  US10/770,966
• Publication Number:
  US 20040157699A1
• Time in Patent Office: 602 Days
• Field of Search: 476/40, 476/41, 476/42, 476/45, 476/61, 476/36, 476/37, 476/38
• US Class Current: 476/45
• CPC Class Codes: B62M 11/12 with frictionally-engaging wheels B62M11/14 takes precedence
• CPC Class Codes: F16H 15/28 with external friction surface
• 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 61/664 Friction gearings
• 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

Abstract

A continuously variable transmission for use in rotationally or linearly powered machines and vehicles. The transmission provides a simple manual shifting method for the user. Further, the practical commercialization of traction roller transmissions requires improvements in the reliability, ease of shifting, function and simplicity of the transmission. The continuously variable transmission may be employed in connection with any type of machine that is in need of a transmission. For example, the transmission may be used in (i) a motorized vehicle such as an automobile, motorcycle, or watercraft, (ii) a non-motorized vehicle such as a bicycle, tricycle, scooter, exercise equipment or (iii) industrial equipment, such as a drill press, power generating equipment, or textile mill.

Claims

1. A continuously variable transmission having a longitudinal axis, comprising;

a plurality of speed adjusters, each having a tiltable axis of rotation, and each speed adjuster located radially outward from the longitudinal axis;

a drive disk annularly rotatable about the longitudinal axis and having a first side contacting a first point on each of the speed adjusters and having a second side facing away from the speed adjusters;

a driven disk annularly rotatable about the longitudinal axis and contacting a second point on each of the speed adjusters;

a generally cylindrical support member annularly rotatable about the longitudinal axis and contacting a third point on each speed adjuster;

a set of perimeter ramps annularly rotatable about the longitudinal axis and adapted to provide rotational and axial force to the second side of the drive disk; and

a set of central ramps annularly rotatable about the longitudinal axis and adapted to transmit torque to the perimeter ramps.

2. The transmission of claim 1, further comprising:

a nut formed by internal threads that are mounted near the center portion of the drive disc; and

a screw in operable contact with the central ramps and adapted to fit within and mate with the nut, wherein the screw and nut transfer torque from the central ramps to the drive disc and apply axial force to the drive disc.

3. The transmission of claim 2, wherein the central ramps further comprise a set of central screw ramps and a complimentary and mating set of central drive shaft ramps, wherein the central ramps are adapted to distribute axial force generation between the screw and nut and the perimeter ramps.

4. The transmission of claim 3, further comprising a generally cylindrical drive shaft that is rotatable about the longitudinal axis and has a first end to which the central drive shaft ramps are operably attached and a second end extending out of the transmission that is adapted to receive torque input to the transmission.

5. The transmission of claim 4, wherein the second end of the drive shaft is adapted to receive input torque from a sprocket of a bicycle.

6. The transmission of claim 4, wherein the second end of the drive shaft is adapted to receive input torque from an automobile engine.

7. The transmission of claim 4, wherein the second end of the drive shaft is adapted to receive input torque from a motorcycle engine.

8. The transmission of claim 4, wherein the second end of the drive shaft is adapted to receive input torque from a tractor engine.

9. The transmission of claim 4, wherein the second end of the drive shaft is adapted to receive input torque from an electric motor.

10. The transmission of claim 4, wherein the output disc is a hub adapted to at least partially encapsulate the speed adjusters and drive disk.

11. The transmission of claim 4, wherein the screw and nut comprise a first axial force generator and the perimeter ramps comprise a second axial force generator.

12. The transmission of claim 11, wherein the axial force component produced by each of the first and second axial force generators varies as the transmission is shifted.

13. The transmission of claim 11, wherein the axial force is larger in a set of low transmission ratios than in a set of high transmission ratios for a corresponding change in transmission ratio.

14. The transmission of claim 11, wherein the first and second axial force generators share production of the axial force to the drive disk.

15. The transmission of claim 11, wherein the first and second axial force generators produce axial force separately, and wherein the first axial force generator produces substantially all of the axial force applied to the drive disk in a high transmission ratio, and the second axial force generator produces substantially all of the axial force applied to the drive disk in a low transmission ratio.

16. The transmission of claim 11, wherein the screw has a face that faces the speed adjusters and has an annular bearing race thereon adapted to receive thrust from a thrust bearing to bias the screw in a direction away from the speed adjusters.

17. The transmission of claim 15, wherein the set of central ramps is adapted to adjust the amount of axial force produced by each of the first and second axial force generators.