CONTINUOUSLY VARIABLE GEAR TRANSMISSION

• US 20130337971A1
• Filed: 07/09/2013
• Published: 12/19/2013
• Est. Priority Date: 12/30/2005
• Status: Active Grant

• Current Assignee: Fallbrook Intellectual Property Company LLC (Fallbrook Technologies Incorporated)
• Original Assignee: Fallbrook Intellectual Property Company LLC (Fallbrook Technologies Incorporated)
• Inventors: Kolstrup, Anders
• Granted Patent: US 9,683,638 B2
• Time in Patent Office: Days
• US Class Current: 476/38
• 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

Abstract

A continuously variable gear is described having an input shaft, a plurality of traction balls distributed radially around the axis, each traction ball is mounted on an axle passing there through, the axles are tiltable in the radial grooves in the housing and support plate. To control the position of the traction balls, the axles are guided in curved slots of a turnable iris plate. To control the axial placement of the traction balls, there is a rotatable input disc positioned adjacent to the traction balls, a rotatable output disc positioned adjacent to the traction balls opposite the input disc, and a pre-spanning ring around the traction balls such that each of the traction balls is making three-point contact with the input disc, the output disc and the pre-spanning ring, the contact surface of the pre-spanning ring having a specific curvature larger than the radius of the traction balls.

Claims

1. A continuously variable gear transmission comprising:

a housing;

an input shaft connected to an input disc;

an output shaft connected to an output disc;

a plurality of traction balls each having a radius (r) and being distributed radially around the input and output discs; and

a rotatable pre-spanning ring, said traction balls each being mounted for rotation around a rotation axis, the angle of the rotation axes being controlled for controlling the transmission ratio of the gear transmission, said traction balls having three-point contact with the input disc, the output disc, and the pre-spanning ring, respectively, the pre-spanning ring being mounted axially displaceable and having a curvature of the surface in contact with the traction balls, said curvature being larger than the radius (r) of the traction balls.

2. A continuously variable gear transmission in accordance with claim 1, said traction balls being mounted on axles for rotation thereon, said axles extending pivotably through radial grooves in said housing and a support plate and through spiral grooves in an iris plate for controlling the angles of the axles.

3. A continuously variable gear transmission in accordance with claim 1, further comprising an axial force generator between the input shaft and the input disc.

4. A continuously variable gear transmission in accordance with claim 3, the forces of the axial force generator being transmitted internally from the input shaft to the input disc and via the traction balls to the output disc and through a thrust bearing back to the input shaft.

5. A continuously variable gear transmission in accordance with claim 1, further comprising a support plate having a minor rotational play around its ideal aligned position.

6. A continuously variable gear transmission in accordance with claim 5, further comprising flexible members for flexibly mounting the support plate and forcing the support plate towards its ideal aligned position.

7. A continuously variable gear transmission in accordance with claim 5, further comprising an actuator having an actuator housing connected to the support plate and an actuator arm connected to the iris plate.

8. A continuously variable gear transmission in accordance with claim 1, the pre-spanning ring being positioned on the outside of the traction balls.

9. A continuously variable gear transmission in accordance with claim 1, further comprising a lubrication system to lubricate and cool the transmission.

10. A continuously variable gear transmission in accordance with claim 9, said lubrication system also lubricating a driven unit connected to the output shaft.

11. A continuously variable gear transmission in accordance with claim 1, configured to drive a compressor or a ventilator.

12. A continuously variable gear transmission in accordance with claim 1, further comprising a disengagement mechanism disengaging the input disc from the traction balls.

13. A continuously variable gear transmission in accordance with claim 12, comprising ramps provided on the iris plate, said ramps forcing the input disc to a position out of engagement with the traction balls.

14. A continuously variable gear transmission in accordance with claim 13, the disengagement being performed with the transmission in a low gearing position.

15. An apparatus for facilitating control of the ratio of a continuously variable transmission (CVT), the apparatus comprising:

a first member having a first plurality of radial grooves;

a second member having a second plurality of radial grooves;

wherein the first and second pluralities of radial grooves are arranged angularly about an axis; and

wherein the first and second members are configured for rotation relative to one another such that during operation of the CVT the first plurality of radial grooves can be angularly misaligned relative to the second plurality of grooves.

16. The apparatus of claim 15, wherein the first member comprises a stationary member.

17. The apparatus of claim 16, wherein the second member comprises a support plate configured for rotation relative to the first member.

18. The apparatus of claim 15, wherein the first member comprises a housing member.

19. The apparatus of claim 18, wherein the second member comprises a support plate.

20. The apparatus of claim 19, further comprising an actuator housing and an actuator arm, the actuator housing coupled to the support plate, and the actuator arm coupled to a mechanism for tilting a plurality of traction balls of a CVT.