GB2373552A

GB2373552A - Cone variator transmission

Info

Publication number: GB2373552A
Application number: GB0103811A
Authority: GB
Inventors: Richard Edward Etherton
Original assignee: Individual
Current assignee: Individual
Priority date: 2001-02-16
Filing date: 2001-02-16
Publication date: 2002-09-25
Anticipated expiration: 2021-02-16
Also published as: GB2373552B; GB0103811D0

Abstract

A CVT has a driving cone 2 and a driven cone 4 arranged parallel and alongside each other, the driving cone 2, which may be turned by a motor via a shaft 3, drives the driven cone 4 by an idler wheel 6 which is positioned between the cones 2,4. The wheel 6 is held in place by the arms 9 of a fork 8 which is rotatable about an axis which causes the wheel 6 to traverse up and down the surfaces of the cones 2,4 to vary the speed of rotation of the driven shaft 4 with respect to the driving shaft 2. In another embodiment, a second driven cone and idler wheel may be added which could be used to drive the driven cone 2 in over-run conditions.

Description

Title Variable Speed Transmission Device The present invention relates to a variable speed transmission device.

Various constantly variable transmission devices (CVT's) have hitherto been known in which opposing cones are interlinked with an idler wheel or ball (s). They have potential applications for use in vehicles to replace conventional manual and automatic gearboxes. A problem with these known systems is that the idler wheels or ball (s) need lubricating and/or wear easily and have a tendency to travel sideways between the cones.

The invention seeks to provide a variable speed transmission device which avoids the above difficulties.

According to the present invention there is provided a variable speed transmission device comprising : a) a first driving cone having a first axis of rotation, b) a second cone alongside and opposing the first cone and adapted to be driven by the first cone, said second cone having a second axis of rotation substantially parallel to the first axis of rotation, c) an idler wheel adapted to be position in contact with the first and second cone and having a third axis of rotation, and d) variable angle means to altel the angle of the third axis of the idler wheel relative to the first and second axis whereby to cause the idler wheel to travel along the length of the cones so as to vary the speed of the first cone relative to the second cone.

Preferably when said idler wheel third axis of rotation is substantially parallel to the first and second axis, said idler wheel remains in a fixed position relative to the first and second cones, and said idler wheel travels along the length of the cones when the third axis is at an angle to said first and second axis.

Preferably the idler wheel has a rounded peripheral wall whereby to limit the contact area of the idler wheel on the cones. The wall may be formed from urethane or other synthetic non-slip surface.

The first and second cones may be formed from metal. The cones may be frusto-conical cones.

The first cone may be rotated by a motor such as an electric motor or internal combustion engine.

The second cone may be connected to drive a wheel or propeller.

An embodiment of the invention will now be described with reference to the accompanying drawings in which: Figure 1 shows a perspective view of a concept demonstrator, Figure 2 shows a schematic view of the demonstrator of Figure 1 with the third axis of the idler wheel angled in one direction relative to the first and second axis, and Figure 3 shows a schematic view of the demonstrator of Figure I with the third axis of the idler wheel angled in the other direction relative to the first and second axis.

Referring to Figure 1 there is shown a variable speed transmission device 1.

Device 1 has a first driving cone 2 having a first axis of rotation X-X. Cone 2 is a frusto-conical cone and may be formed of metal. Cone 2 may be connected by its shaft 3 to a motor such as an electric motor or internal combustion engine.

Device 1 has a second cone 4 alongside and opposing the first cone 2 and adapted to be driven by the first cone 2. Second cone 4 has a second axis of rotation Y-Y substantially parallel to the first axis of rotation X-X. Cone 4 is a frusto-conical cone and may be formed of metal. Cone 4 may be connected by its shaft 5 to a wheel or propeller (or other object) to be rotated.

An idler wheel 6 is positioned between and in contact with the first cone 2 and the second cone 4, and has a third axis of rotation Z-Z. Idler wheel 6 has a rounded peripheral wall 7 whereby to limit the contact area of the idler wheel on the cones. The wall 7 may be formed from urethane or other synthetic non-slip surface.

Idler wheel 6 is supported by a y-shaped fork 8, with the arms 9 of the fork supporting the wheel and the base shaft 10 being rotatable. The fork 8 forms a variable angle means to alter the angle of the third axis of the idler wheel relative to the first and second axis whereby to cause the idler wheel to travel along the length of the cones so as to vary the speed of the first cone relative to the second cone as described below with reference to Figures 2 and 3.

When said idler wheel third axis of rotation is substantially parallel to the first and second axis as shown in Figure 1, the idler wheel remains in a fixed position relative to the first and second cones. As the first cone rotates as shown by the arrow"A"so this tends to pull the idler wheel onto the surface of the two cones causing the second cone to rotate in the direction of arrow"B".

As shown in Figure 2, if the third axis of rotation Z-Z is rotated clockwise by rotating fork 8 clockwise so it is at an angle to said first and second axis, the idler wheel will travel along the cones towards the narrow end of cone 2. This will decrease the speed of rotation of cone 4 relative to cone 2.

As shown in Figure 3, if the third axis of rotation Z-Z is rotated anti-clockwise by rotating fork 8 anti-clock wise so it is at an angle to said first and second axis, the idler wheel will travel along the cones towards the narrow end of cone 4. This will increase the speed of rotation of cone 4 relative to cone 2.

It will be appreciated that the (rive ratio between the two cones can be adjusted by"steering"the idler wheel by rotating it so th t it travels to achieve the desired ratio between the cones.

The variable speed transmission device of the invention may take a form different to that specifically described above. For example the variable angle means could be other than a y-shaped fork for the idler wheel.

The device of the invention may be used to drive the wheel of a vehicle. In this respect a third cone could be driven by the first cone by an additional idler wheel, with the third cone and additional idler wheel on the c her side of the first cone to the second cone and its idler wheel shown in Figure 1. The third Lad second cones would be connected (e. g. with a chain) to co-rotate and the third cone wvulJ be used to drive the first cone in over-run conditions when the wheel is driving the motor driving the first cone.

The transmission device of the invention may be used in many different applications.

Further modifications will be apparent to those skilled in the art without departing from the scope of the present invention.

Claims

CLAIMS 1. A variable speed transmission devise comprising: (a) a first driving cone having a first axis of rotation, (b) a second cone alongside and opposing the first cone and adapted to be driven by the first cone, and having a second axis of rotation substantially parallel to the first axis of rotation, (c) an idler wheel adapted to be position in contact with the first and second cone and having a third axis of rotation, and (d) variable angle means to alter the third axis of the idler wheel relative to the first and second axes whereby to cause the idler wheel to travel along the length of the cones so as to vary the speed of the first cone relative to the second cone, (e) said idler wheel having a rounded peripheral wall which is resiliently-faced.
2. A device as claimed in Claim 1 wherein the resilient wall is of non-slip plastics material.
3. A device as claimed in Claims 2 wherein the resilient wall is of urethane.
4. A device as claimed in Claims 1,2 or 3, wherein when said idler wheel third axis of rotation is substantially parallel to the first and second axis, said idler wheel remains in a fixed position relative to the first and second cones, and said idler wheel travels along the length of the cones when the third axis is as an angle to said first and second axis.
5. A device as claimed in any one of Claims 1 to 4 wherein the first and second cones are formed from metal.
6. A device as claimed in any one of Claims 1 to 5, wherein the cones are frusto conical.
7. A device as claimed in any one of Claims 1 to 6 wherein the first cone is rotatable by a motor.
8. A device as claimed in Claim 7, wherein the motor is an electric motor.
9. A device as claimed in Claim 7, wherein the motor is an internal combustion engine.
10. A device as claimed in any one of Claims 1 to 9, wherein the second cone is connected to drive a wheel.
11. A device as claimed in any one of Claims 1 to 9, wherein the second cone is connected to drive a propeller.
12. A device as claimed in any one of Claims 1 to 11, wherein the idler wheel is supported by a y-shaped fork with the arms of the fork supporting the wheel, and provided with a shaft disposed on said third axis of rotation, whereby rotation of the shaft alters the angle of the third axis relative to said first and second axes of said first and second cones.
13. A device as claimed in any one of the Claims 1 to 12, provided with a third driven by the first cone by way of an additional idler wheel, with the third cone and additional idler wheel on the other side of the first cone to the second cone and its idler wheel.
14. A device as claimed in Claim 13 wherein the third and second cones are connected to co-rotate and the cone used to drive the first cone in over-run conditions.
15. A variable speed transmission device, substantially as hereinbefore described, with reference to the accompanying drawings.