GB2619752A

GB2619752A - A gearing device

Info

Publication number: GB2619752A
Application number: GB2208844.7A
Authority: GB
Inventors: James Dunstan Edmund
Original assignee: Individual
Current assignee: Individual
Priority date: 2022-06-16
Filing date: 2022-06-16
Publication date: 2023-12-20
Also published as: GB202208844D0

Abstract

A gearing device consisting of axle 10, input disc 9 with an inner convex friction surface, intermediate rollers with ends 12, and output disc 17 with an inner concave friction surface. The gear ratio is altered by the radial displacement of the intermediate rollers under urging from a gearshift means. The radius of curvature of the output disc may be three times that of the input disc and rollers. The gearing device may be for a bicycle or other pedal cycle and the gearshift means may be a gearshift cable operated by the rider.

Description

A GEARING DEVICE

Field of the Invention

The present invention relates to a gearing device, in particular a device for providing variable gearing; more particularly but not exclusively a device for incorporation on a bicycle.

Background

Many societies have increased interest in cycling, as a low-impact and healthy mode of transport..

For cyclists to enjoy their cycling it is frequently important to maintain their cycles, 15 such as bicycles, as in the event of poor maintenance for example rust, ingress of water and humidity, the mechanism of a cycle may tend towards failure.

In particular it is relatively common for gears to become ineffective, which can lead to more difficulty cycling. Additionally or alternatively standard gear mechanisms on 20 bicycles and the like tend to be either inflexible and robust, or flexible and complicated if allowing for more choice of gear for example,.

Prior Art

DE 102 012 022 953 (STRAUSS) discloses a transmission comprises a large friction ring that includes a radius with respect to a central axis, which is greater than a radius of a small friction ring. The small ring, a tapered-roller support with roller and the large ring are respectively designed as an outer gear, a bar with planets and an inner gear, to receive the rotational drive power, and output through the respective components.

EP 2 084 428 (KANERVO) discloses a frictional planetary gear with vadator action, which includes -a body -a rotary ring -a first set of planet wheels, rolling along an internal rolling surface of the rotary ring -a fixed rotation roller path integrally associated with the body -a second set of planet wheels, rolling along the fixed rotation roller path -pins for the planet wheels, and -a bogie or a planet flange, having the pins of the planet wheels supported thereon, characterized in that the planet wheels of the second set are supported by means of a resilient central element for radial displacement and that the fixed rotation roller path has a diameter which is adjustable.

GB 2006 09 647 (ELLIS) discloses a continuously variable transmission comprising a casing defining an axis of rotation, input and output shafts on said axis, respective inner race rims on said shafts, respective outer race rims about said inner race rims, a planet carrier rotatable on said axis, and planets carried by said carrier in rolling contact with said inner and outer race rims and adapted to transmit torque by rolling traction, said inner race rims and outer race rims being relatively movable along said axis, and said planets being relatively movable orthogonal to said axis to vary the speed ratio between said input and output shafts, and a controller being provided to vary the axial separation of said race rims.

The present invention arose in order to overcome problems suffered by existing devices.

Summary of the Invention

According to the present invention there is provided a gearing device comprising: a central axle; an input plate having an inner face with a first radius of curvature and an output plate having an inner face with a second radius of curvature; a plurality of rollers having a first end arranged to contact the inner face of input plate and a second end arranged to contact the inner face of the output plate; wherein the input plate and output plate are spaced apart on, and arranged to rotate about, the central axle; and wherein the rollers are arranged to move in a radial direction under urging from a gearshift means.

The inner faces of the plates are provided with surfaces that are arranged for interaction or engagement, wherein such engagement may be used to drive relative movement on the axle.

In this way more particularly the device is enabled so as to alter gearing between the 35 plates, whereby an input rotational speed at the input plate is geared by the device to provide a different output rotational speed.

It may be envisaged that the axle in use comprises a separate part, passing through a collar adapted to connect thereto, or that the axle comprises an integrated part of the device.

In some embodiments the roller ends have a radius of curvature equal to the inner face of the input plate. It may be envisaged that the roller ends have a radius of curvature a third of that of the inner face of the output plate.

In some embodiments therefore it may be envisaged that the roller ends are in partial contact with the plates in use.

In some embodiments the rollers are arranged to move in an axial slot in a shift housing under urging of the gearshift means.

In some embodiments the rollers are arranged to move in a radial slot in a shifting plate under urging of the gearshift means In some embodiments the gearshift means comprises a chain, cable or wire and a 20 sprocket, and it may be envisaged that such means is manually operable.

In some embodiments the gearshift means comprises a bearing with cam engagement, such as is known in the art, whereby free wheeling in the reverse direction is permitted.

In some embodiments an axial tensioning means is provided, in particular a means for axial compression, being adapted to hold the roller ends on the plates, or in contact with the plates, or more particularly in frictional contact with the plates.

In some embodiments the axial tensioning means comprises the connection of, or a connector of the axle to a plate, such connector having a radially distributed chamfer arranged to drive movement of said plate along the axle towards the opposing plate during axial rotation of the plate.

In some embodiments the axial tensioning means comprises a chamfered connector at connection of each plate to the axle, wherein the chamfer of the connector(s) are arranged to drive axial movement, or compression, of the plates towards one another, during rotation about the axis.

In some embodiments the axial tensioning means comprises a resilient means, for 5 example a spring bias means.

According to a further aspect of the present invention there is provided a bicycle containing a device substantially as described herein.

A preferred embodiment of the invention will now be described by way of example only and with reference to the Figures in which:

Brief Description of Figures

Figure 1 shows an isometric view of an embodiment of the device according to the present invention; Figure 2 shows a reverse isometric view of the embodiment of the device shown in 20 Figure 1; Figures 3 show an exploded isometric view of the embodiment of the device shown in Figure 1; Figure 4 shows a reverse exploded isometric view of the embodiment of the device shown in Figure 1; Figure 5 shows a partial isometric sectional view of the embodiment of the device shown in Figure 1; And Figure 6 shows a sectional view of an intermediate roller as used in the embodiment of the device shown in Figure 1.

Detailed Description of Figures

With reference to the figures there is shown a gearing device 99 generally comprising: a central axle 10; an input plate 9 having a convex inner face, providing a friction surface 39, with a first radius of curvature and an output plate 17 having an 5 inner face, providing a friction surface 39, with a second radius of curvature; a plurality of rollers 12 having a first end with a friction surface 32 arranged to contact the inner face of input plate 9 and a second end with a friction surface 32 arranged to contact the inner face of the output plate 17; wherein the input plate and output plate are spaced apart on, and arranged to rotate about, the central axle 10; and wherein 10 so as to alter gearing between the plates the rollers are arranged to move in a radial direction in slots curving out spirally in a gear shift control disc 13 under urging from a gearshift means.

In particular reference to the pictured explosion of the embodiment of the device 15 shown, the embodiment comprises: 1.1ock nut (steel) 2.sprocket (steel) 3.hub casing (aluminium) 4.bearings 5.spacer (steel) 6.input axial pressure chamfer (steel) 7.bearings 8.Iinear rail bearing 9.input friction plate 10.axle and central plate with roller slots 11.thrust bearings 12.intermediate rollers 13.gear shift control disc 14.thrust bearing 15.gearing plate with roller slot flanges x3 mating with the slots in the axle plate 10 16.bearing 17.output friction plate 18.output axial pressure chamfer (steel) 19.freewheel ratchet (steel) 20.hub casing (aluminium) 21 thrust bearing 22.gear shift joint (steel) 23.1ock nut (steel) The embodiment shown in the figures provides a hub gearing system or hub gear for a commuter bicycle.

The hub gear may comprise a spiral return spring, biased to rotate the control disc 13 anticlockwise to push the rollers 12 outwards radially, and therefore act against the 10 chamfers.

This hub gear is driven by a standard crankset and chain, which drives the sprocket and thereby turns the friction input plate 9. The friction input plate has a concave inner face with an internally convex annular friction surface 39 on the inside of its 15 circumference Drive is transmitted to the output plate 17 by the intermediate rollers 12, which have convex ends providing friction surfaces 32, which are contacting the plates in use.

The output plate 17 provides a concave friction surface, with a radius of curvature three times that of the curved surfaces on the input plate and the intermediate rollers.

This, and the fact that both input and output plates are arranged to be displaced along the axle aid the geometry and function.

The chamfers 69, 96 of the plates 6, 18 provide an axial compressive force for the tensioning means, placing axial pressure when the device, or more particularly lock nuts, are tightened, as torque is applied, to act against the datum provided by the lock nuts. The axial compressing force, in operation, is derived primarily from the torque applied via the chamfers 69, 96 wherein the lock-nuts provide the necessary reaction to it.

The tensioning means may further include a spring to push the plates towards each other, in addition or the alternative.

As the user changes the gear the intermediate rollers 12 move in an axial direction in the slots in the gear shift control disc 13, and radially in relation to the axle in the slots on the axle plate 10. This shift changes the radii of contact between the intermediate rollers and the friction surfaces, when the input and output plates move closer or further apart in an axial direction.

The rollers comprise bearings so as to allow differing rotation between the pads travelling in the slots, namely a roller casing 63 and a shaft 64, and the' friction surfaces provided by the ends. The rollers comprise thrust bearings 61 between the friction surfaces provided by the ends and the roller casing, and internal bearings 62 are provided between the shaft and the casing, as shown in Figure 6.

Advantageously this allows gear ratios to be continuously variable across a wide range, both increasing and decreasing a velocity ratio, which requires only one 15 control. Furthermore, gear mechanisms will not be exposed, so are less likely to rust or become damaged.

The invention has been described by way of examples only and it will be appreciated that variation may be made to the above-mentioned embodiments without departing 20 from the scope of protection as defined by the claims.

Claims

Claims 1. A gearing device comprising: a central axle; an input plate having an inner face with a first radius of curvature and an output plate having an inner face with a second radius of curvature; a plurality of rollers having a first end arranged to contact the inner face of input plate and a second end arranged to contact the inner face of the output plate; wherein the input plate and output plate are spaced apart on, and arranged to rotate about, the central axle; and wherein so as to alter gearing between the plates the rollers are arranged to move in a radial direction under urging from a gearshift means.
2. A gearing device according to claim 1 wherein the roller ends have a radius of curvature equal to the inner face of the input plate.
3. A gearing device according to claim 1 or 2 wherein the roller ends have a radius of curvature a third of that of the inner face of the output plate.
4. A gearing device according to any preceding claim wherein the roller ends in partial contact with the plates.
5. A gearing device according to any preceding claim wherein the rollers arranged to move in an axial slot in a shift housing under urging of the gearshift means.
6. A gearing device according to any preceding claim wherein the rollers arranged to move in a radial slot in a shifting plate under urging of the gearshift means
7. A gearing device according to any preceding claim wherein the gearshift means comprises a cable and sprocket.
8. A gearing device according to any preceding claim wherein the gearshift means comprises a bearing with cam engagement.
9. A gearing device according to any preceding claim comprising an axial tensioning means to hold the roller ends on the plates.
10. A gearing device according to claim 9 wherein the axial tensioning means comprises a connector of the axle to a plate, the connector having a radially distributed chamfer arranged to drive movement along the axle towards the opposing plate during axial rotation of the plate.
11. A gearing device according to claim 9 or 10 wherein the axial tensioning means comprises a chamfered connector at connection of each plate to the axle.
12. A gearing device according to claim 9, 10 or 11 wherein the axial tensioning means comprises a resilient means
13. A pedal bicycle containing a device according to any of the preceding claims.