Continuously variable transmission

• US 7,462,127 B2
• Filed: 03/19/2007
• Issued: 12/09/2008
• Est. Priority Date: 04/26/2001
• Status: Expired due to Fees

• 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): Wright; Dirk
• Application Number:
  US11/688,124
• Publication Number:
  US 20070179013A1
• Time in Patent Office: 631 Days
• Field of Search: None
• US Class Current: 476/38
• 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 is disclosed 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 present invention includes a continuously variable transmission that 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 outwardly from the longitudinal axis,

an input disk contacting a first point on each of the speed adjusters;

an output disk contacting a second point on each of the speed adjusters;

a support member annularly rotatable about the longitudinal axis, located radially inwardly from the speed adjusters and contacting a third point on each of the speed adjusters, the support member having a first end and a second end that are axially separated and having a first diameter at said first end and a second diameter at said second end, wherein the support member is axially movable; and

wherein said first diameter is different from said second diameter.

2. The transmission of claim 1, further comprising a torque responsive element adapted to urge the input disk and output disks closer together in response to an increase in torque.

3. The transmission of claim 2, wherein the torque responsive element urges the input disk and output disks closer in a manner whereby the urge of the torque responsive element varies in a non-linear manner with respect to the increase in torque.

4. The transmission of claim 1, further comprising:

a tubular sleeve coaxially within the support member;

a pin;

a worm drive comprising;

a rod;

a set of acme threads attached to a first end of the rod; and

wherein the pin is attached to the inside of the sleeve and engages with the worm that also fits inside the sleeve such that as the rod is rotated the sleeve moves axially along the longitudinal axis of the transmission.

5. The transmission of claim 4, wherein the axial movement of the sleeve causes axial movement of the support member further causing the transmission to shift.

6. The transmission of claim 5, further comprising:

a stationary hollow shaft having a first end near the center of the transmission and a second end extending coaxially along the longitudinal axis of the transmission away from the first end;

a second end of the rod opposite the first end;

a shifting tube that fits coaxially around the second end of the hollow shaft with which it is in sliding contact; and

wherein the shifting tube is attached to the second end of the rod so as to actuate the worm drive.

7. The transmission of claim 6, wherein the shifting tube and the hollow shaft are engaged so as to amplify the actuation of the worm drive.

8. The transmission of claim 7, wherein the shifting tube and the hollow shaft are engaged so as to diminish the actuation of the worm drive.

9. The transmission of claim 7, further comprising a spring member that engages with the shifting tube to bias the rotation of the shifting tube.

10. The transmission of claim 6, further comprising a servo motor engaged with the shifting tube and that receives an input control signal so as to rotate the shifting tube in response to receiving an electronic input signal from an operator.

11. The transmission of claim 4, wherein the tubular sleeve comprises:

a first end; and

a second end, wherein the first end engages the pin and is thicker than the second end.

12. An axial force generation mechanism comprising:

an input disk having ramp side that faces away from speed adjusters;

a torque responsive element comprising;

a bearing disk similar in diameter to the input disk that is positioned axially near the input disk and that rotates about the same axis as the input disk and has a first side that faces the input disk and wherein the bearing disk provides input torque to the input disk;

a first set of ramps located annularly about the longitudinal axis of a transmission, the first set of ramps fixed to the first side of the bearing disk at a fixed radial position;

a second set of ramps located annularly about the longitudinal axis of the transmission that are fixed to the ramp side of the input disk at a fixed radial position similar to that of the first set of ramps;

a set of ramp bearings which are annularly positioned at a radial position necessary to interact with and fit between the first and second set of ramps;

wherein the first set of ramps rotate with the bearing disk and engage the ramp bearings, which in turn engage the second set of ramps such that the input torque of the bearing disk is converted by the first set of ramps to an axial force component and a rotational force component which axial and rotational force components are transferred to the input disk via the ramp bearings and the second set of ramps;

wherein the first and second set of ramps engage the ramp bearings at various points so as to allow axial movement of the input disk; and

wherein at least one of the first or second set of ramps has a discontinuous slope.

13. The mechanism of claim 12, wherein at least one of the first or second set of ramps has a slope that changes at a constant rate.

14. The mechanism of claim 13, wherein at least one of the first or second set of ramps has a slope that changes at a variable rate.

15. The mechanism of claim 12, wherein at least one of the first or second set of ramps has a changing slope that may be negative or positive with respect to the disk surface that set of ramps is mounted to.

16. A transmission comprising:

a plurality of spindle supports, each mounted to one end of a spindle, and extending radially inwardly from the spindles;

a first camming surface adjacent to the first end of a support member;

a second camming surface adjacent to a second end of a support member, wherein the first and second camming surfaces are each located annularly around a longitudinal axis, and wherein the first and second camming surfaces are in contact with the spindle supports and are axially movable, wherein such axial movement causes radial movement of the spindle supports to tilt the axis of rotation of speed adjusters.

17. The transmission of claim 16, wherein the first camming surface and the second camming surface are in the form of convex radii.

18. The transmission of claim 16, wherein the first camming surface and the second camming surface are shaped differently.