GB2526586A

GB2526586A - Drive system

Info

Publication number: GB2526586A
Application number: GB1409490.8A
Authority: GB
Inventors: William Dowell; Adrian Dowell
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-05-28
Filing date: 2014-05-28
Publication date: 2015-12-02
Also published as: GB201409490D0

Abstract

A continuously variable transmission unit comprises a plurality of drive units each comprising a tapered input roller 10, a tapered output roller 11 and a drive belt 12 interconnecting said rollers, wherein all input and output rollers of the transmission unit are positioned with their axes parallel and with the tapers of the input rollers opposing those of the output rollers, the unit further comprising an adjuster unit (4, figure 2) that controls the position of the drive belts in a direction parallel to the axes of the rollers. The adjuster unit may comprise a hollow shaft with an externally threaded section (16, figure 10), an adjuster nut mounted on the shaft and a belt tensioner (18, 19) for each of the drive units. The system is preferably electronically controlled. Also disclosed is a bicycle comprising the transmission unit of the invention.

Description

Intellectual Property Office Application No. GB1409490.8 RTTVT Date:5 November 20t4 The following terms are registered trade marks and should be read as such wherever they occur in this document: NuVinci, Bluetooth Intellectual Property Office is an operating name of the Patent Office www.ipo.govuk

TITLE

Drive System

FIELD OF INVENTION

This invention relates to the drive system, particularly an electronically controlled, automatically adjusting, variable speed drive system.

BACKGROUND OF THE INVENTION

Currently the majority of cycle gear systems comprise either derailleur type gear change mechanisms or a wheel hub with integral gearing, or more recently a variable speed wheel hub. These systems are operated either mechanically from a handlebar or frame mounted lever via a Bowden Cable type arrangement or more recently the same mechanical operation is performed by a servo type devise located adjacent to the gear change mechanism performing the mechanical operation in response to control signals from a handlebar or frame mounted electrical switch.

The present invention provides a fully integrated digital control system with data acquisition to provide feedback to the rider and operate the fully automatic speed change.

DESCRIPTION OF THE PRIOR ART

Derailleur type gear changers Gear Hub Devices Nu-Vinci Stepless gear hub

SUMMARY OF THE INVENTION

Whist the derailleur system and wheel hub with internal gearing are well proven they provide gear ratios in distinct steps. The variable speed wheel hub is relatively novel and does offer step-less gear change. However all of the above are predominately mechanical systems with the facility to attach electro mechanical actuators to offer some additional functionality.

The present invention provides a fully integrated digital control system with data acquisition to provide feedback to the rider and fully automatic speed change based on maintaining constant pedal torque or speed values using a stepless ratio change.

Additionally the system has a human interface display and is fully compatible with portable electronic devices.

Furthermore due to the nature of the design, the present invention is suited to harmonizing with an Anti-lock Braking System (ABS) and Traction Control.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention comprises a stepless variable speed wheel hub comprising a series of tapered input and output rollers.

The input and output rollers are arranged in pairs around the wheel axle. For each pair of input and output rollers there is an interconnecting drive belt. A stepper motor rotates a cylindrical adjuster tube about the wheel axle, which, via a screw thread, provides lateral displacement of the adjuster unit, the stepper motor controller providing positional feedback to the control unit.

The adjuster unit with integral spring loaded belt tensioning devices controls the lateral position of the drive belts which in turn changes the rotational speed ratio of the output rollers in relation to the input rollers. All of the input rollers are driven simultaneously by a single input gear such that each pair of tapered rollers work in unison. Similarly all of the output rollers drive a single output gear.

The input gear rotates about the wheel axle and has a chain sprocket attached to one end and a spur gear attached to the other end, which engages with the gears of the input rollers.

The output gear, which is driven by the output rollers and also engages with the wheel hub, is designed such that it is in two sections, and mechanically joined in a manner which allows limited independent rotation of the two pads about the wheel axle, the independent rotation being resisted by a series of compression springs.

The gears of the output rollers indirectly engage with the first part of the output gear whilst the second part engages with the wheel hub.

By using two encoders to measure the relative displacement of the two components of the output gear caused by resistance to drive, the applied torque is calculated by the control unit.

A microprocessor mounted on the cycle receives data about the operating status of the cycle. Examples of cycle data include speed, pedal-crank torque, pedal-crank speed. An electro mechanical device is in connection with the variable speed transmissions to adjust the speed ratios. The microprocessor considers user defined parameters and vehicle data to instruct the electro mechanical devise to adjust the variable speed transmission ratio accordingly and provide user feedback via a human interface device. The microprocessor will also interface with portable electronic devices.

The system includes a generator, which powers the system and recharges the integral battery.

Conveniently, the scope of the invention, for which protection is required, is set out in the Claims appended hereto.

The now follows by way of example of the present invention a detailed description to be read with reference to the accompanying drawings in which: Figure 1 is a left hand front perspective view of a hub assembly with pads broken away for clarity; Figure 2 is a right hand front perspective view of the hub assembly of Figure 1 with parts broken away for clarity; Figure 3 is a left hand front perspective view of the hub casing; Figure 4 is a right hand front perspective view of the hub casing; Figure 5 is a right hand perspective view of an input unit of the present invention; Figure 6 is a left hand perspective view of the input unit of Figure 5; Figure 7 is a right hand perspective view of a drive unit of the present invention; Figure 8 is a left hand perspective view of the drive unit of Figure 7; Figure 9 is a right hand perspective view of an adjuster unit of the present invention; Figure 10 is a left hand perspective view of the adjuster unit of Figure 9; Figure 11 is a right hand perspective view of an output unit of the present invention; Figure 12 is a left hand perspective view of the output unit of Figure 11; Figure 13 is a right hand perspective view of a hub control unit of the present invention; Figure 14 is a left hand perspective view of the hub control unit of Figure 13; Figure 15 is a side perspective view of a hub axle of the present invention; and, Figure 16 is an opposite side perspective of the hub axle of Figure 15.

Generally the present invention comprises of a stepless variable speed wheel hub; a hand operated control unit and human/machine interface device.

Specifically the stepless variable speed hub comprises; a wheel axle 1; an input unit 2; a drive unit 3; an adjuster unit 4; an output unit 5; a hub control unit 6 and a wheel hub 7, see Figures 1 and 2.

The input unit 2 comprises; a chain sprocket 8 and an input gear 9, see Figures 5 and 6.

The drive unit 3, see Figures 7 and 8, comprises four drive modules, each drive module comprising; an input roller 10; an output roller 11; a drive belt 12; input end plate 13; output end plate 14 and a housing 15.

The adjuster unit 4, see Figures 9 and 10, comprises; an adjuster tube 16; a crucifix adjuster 17; spring loaded belt tensioner pistons 18; belt tensioner pulleys 19 and adjuster pulleys 20.

The output unit 5, see Figures 11 and 12, comprises; idler gears 21; a ring gear assembly 22; a generator drive gear 23 and a torque encoder drive gear 24.

The hub control unit 6, see Figures 13 and 14, comprises; a stepper motor with drive gear 25; a generator 26; a speed encoder 27; a torque encoder 28; a microprocessor 29 and a power supply control board 30.

The wheel hub 7, see Figures 3 and 4, comprises a central casing 31; an input cover 32; and an output cover 33.

The wheel axle unit 1, see Figures 15 and 16, comprises an axle 34 and an adaptor bush 35.

The hand operated control unit comprises; a push button for mode selection; a rocker switch to change speed ratio or torque requirements and heart monitor, none of which are shown in the accompanying drawings.

The human/machine interface device, also not shown, comprises; a microprocessor; control buttons; a rechargeable battery and a display unit.

The input unit 2 is mounted on the wheel axle 1 via two bearings and is driven by the chain sprocket 8. As the input unit 2 is rotated about the wheel axle 1, all four of the bearing mounted input rollers 10 are driven simultaneously about their own axes. As each of the four input rollers 10 rotate they each drive their associated bearing mounted output roller 11 about their own axes via the four independent drive belts 12. The adjuster unit 4 includes four spring loaded belt tensioner pulleys 19,\which ensure that each of the drive belts 12 are independently and accurately tensioned.

All of the four output rollers 11 simultaneously drive the ring gear assembly 22, which is attached to the wheel hub 7 and rotates about the wheel axis, via the four idler gears 21. The ring gear assembly 5 is designed such that it is in two sections, and mechanically joined in a manner, which allows limited independent rotation of the two parts about the wheel axle 1, the independent rotation being resisted by a series of compression springs, not shown. The bearing mounted idler gears 21 engage with the first pad of the ring gear assembly 22 whilst the second part engages with the wheel hub 7. As the ring gear assembly 22 rotates about the wheel axis, the bearing mounted wheel hub 7 is rotated accordingly.

When speed change is required, the stepper motor 25 rotates the threaded cylindrical adjuster tube 16 about the wheel axis, which, via the screw thread, drives the crucifix adjuster 17 along the wheel axis. As the crucifix adjuster 17 is driven along the wheel axis, the drive belts 12 are simultaneously moved along the length of the tapered input 10 and output rollers 11 thus modifying the output roller 11 rotational speed in relation to the input roller 10 rotational speed.

As the ring gear assembly 22 rotates, the rotational speeds of the two sections are measured independently by the speed 27 and torque 28 encoders respectively.

When there is a change to the torque applied, first part of the ring gear will move relative to the second part and a positional differential will be detected by the encoders.

The ring gear 22 drives the generator 26, which charges the systems rechargeable battery, not shown.

The hub microprocessor 29 collects the signals from the speed encoder 27 and torque 28 encoder and sends the information to the human/machine interface device via a serial comms link. Additionally as a consequence of signals from the human/machine interface device via the serial comms link, the microprocessor controls the operation of the stepper motor 25 in terms of speed and rotational direction. The serial comms link can be either wired or wireless in nature.

The power supply control board 30 ensures that the generators' 26 electrical output is of the appropriate voltage and charging current for the rechargeable battery.

Claims

CLAIMS1. A continuously variable transmission unit mounted on a longitudinal axis, comprising a plurality of drive units, each comprising a tapered input roller, a tapered output roller and an interconnecting drive belt; the tapered input and output rollers being positioned radially outwards from, and with their axes parallel to, the longitudinal axis and with the taper of the input rollers opposing those of the output rollers such that the rotational speed of the output rollers in relation to that of the input rollers is dependent upon the lateral location of the drive belt as controlled by an adjuster unit of the transmission.
2. A continuously variable transmission unit according to Claim 1, characterised in that the adjuster unit comprises a hollow shaft with an externally threaded section, concentrically aligned with the longitudinal axis, an adjuster nut mounted on the hollow threaded shaft and a plurality of belt tensioners for each for each of said drive units.
3. A continuously variable transmission unit according to Claim 2, characterised in that the transmission unit comprises an electrical-mechanical device that causes, when the transmission unit is in use, the hollow shaft to be rotated about the longitudinal axis, which, in turn, drives the adjuster nut laterally along the length of the hollow shaft, the direction of travel of the adjuster nut relating to the rotational direction of the hollow threaded shaft.
4. A continuously variable transmission unit according to Claim 3, characterised in that the electrical-mechanical device may be a stepper motor.
5. A continuously variable transmission unit according to Claim 3, characterised in that the electrical-mechanical device may be a servo.
6. A continuously variable transmission unit according to Claim 3, characterised in that the adjuster unit includes means for mechanically restricting its movement along the longitudinal axis.
7. A continuously variable transmission unit according to Claim 5, characterised in that the adjuster nut comprises for each drive unit a hollow supporting tube extending radially, or substantially so, from the longitudinal axis, each of the supporting tubes providing location for respective belt tensioner pulleys, the adjuster nut also providing support for associated adjuster pulleys of each drive unit
8. A continuously variable transmission unit according to Claim 6, characterised in that the belt tensioner of each adjuster unit comprises a tension spring having a first end and a second end, the belt tensioner guides being attached to their respective first ends of their tension springs with the second ends of the tension springs being attached to the adjuster nut.
9. A continuously variable transmission unit according to Claim 6, characterised in that the belt tensioner of each adjuster unit comprises a compression spring having a first end a second end, the belt tensioner guides being attached to their respective first ends of their compression springs with the second ends of the compression springs being attached to the adjuster nut.
10. A continuously variable transmission unit according to Claims 7 and 8, characterised in that the belt tensioning springs may be either of the compression or tension springs or a combination of the two.
11. A continuously variable transmission unit according to Claim 9, characterised in that the belt tensioner of the adjuster unit is of geometric section and free to travel along the corresponding hollow section of the supporting tube of the adjuster nut in a direction perpendicular to the longitudinal axis to be acted upon by the belt tensioner such as to apply an appropriate belt tensioning force.
12. A continuously variable transmission unit according to Claim 9, characterised in that the belt tensioner of the adjuster unit is of non-geometric section and free to travel along the corresponding hollow section of the supporting tube of the adjuster nut in a direction perpendicular to the longitudinal axis to be acted upon by the belt tensioner such as to apply an appropriate belt tensioning force.
13. A continuously variable transmission unit according to Claim 11, characterised in that the location of the belt tensioner and a belt position adjuster in relation to the belt drive prevents the adjuster nut from rotating about the hollow threaded shaft.
14. A continuously variable transmission unit according to any one of the preceding Claims, characterised in that when one drive unit is included, the tapered input rollers are driven simultaneously by a common drive gear, which rotates about the longitudinal axis.
15. A continuously variable transmission unit according to Claim 13, characterised in that the drive gear comprises a cylindrical shaft having a toothed gear at one end to drive the input rollers and a means at the other end thereof at which to attach a chain drive sprocket.
16. A continuously variable transmission unit according to Claim 14, characterised in that when the unit is in use and more than one drive unit is included, the tapered output rollers are connected simultaneously to a common drive gear, which rotates about the longitudinal axis.
17. A continuously variable transmission unit according to Claim 15, characterised in that the drive gear comprises means to permit relative movement between its components parts.
18. A continuously variable transmission unit according to Claim 16, characterised in that the drive gear comprises one or more means to resist relative movement between its respective parts.
19. A continuously variable transmission unit according to Claim 17, characterised in that said means to resist relative movement between the respective parts of the drive gear comprises one or more compression springs.
20. A continuously variable transmission unit according to Claim 1, characterised in that the system is electronically controlled.
21. A continuously variable transmission unit according to Claim 20, characterised in that the electronic control is by a microprocessor.
22. A continuously variable transmission unit according to Claim 20, characterised in that the electronic control uses encoders to measure speed values.
23. A continuously variable transmission unit according to Claim 22, characterised in that the electronic control calculates torque values from the measured speed values.
24. A continuously variable transmission unit according to Claim 20, characterised in that the electronic control adjusts the continuously variable transmission unit to maintain user defined values.
25. A continuously variable transmission unit according to Claim 24, characterised in that the user defined values includes the input pedal-crank torque limit.
26. A continuously variable transmission unit according to Claim 24, characterised in that the user defined values includes the input pedal-crank rotational speed.
27. A continuously variable transmission unit according to Claim 20, characterised in that the continuously variable transmission unit and the electronic controller are connected electrically.
28. A continuously variable transmission unit according to Claim 27, characterised in that the connection between the continuously variable transmission unit and the electronic controller is of a wired nature.
29. A continuously variable transmission unit according to Claim 27, characterised in that the connection between the continuously variable transmission unit and the electronic controller is of a wireless nature.
30. A continuously variable transmission unit according to Claim 20, characterised in that the continuously variable transmission unit includes a generator to recharge the power supply battery.
31. A continuously variable transmission unit according to Claim 20, characterised in that the control unit includes communication with a portable electronic device.
32. A continuously variable transmission unit according to Claim 31, characterised in that the communication with a portable electronic device is of a wired nature.
33. A continuously variable transmission unit according to Claim 31, characterised in that the communication with a portable electronic device is of a wireless nature.
34. A continuously variable transmission unit according to Claim 33, characterised in that the wireless communication is in the form of Bluetooth technology
35. A continuously variable transmission unit according to Claim 33, characterised in that the wireless communication is in the form of Near Field Communication technology.
36. A continuously variable transmission unit according to Claim 31, characterised in that the portable electronic device is a smartphone.
37. A continuously variable transmission unit according to Claim 31, characterised in that the portable electronic device is a tablet computer.
38. A continuously variable transmission unit according to Claim 20, characterised in that the control unit includes video recording capabilities.
39. A continuously variable transmission unit according to Claim 38, characterised in that the video recording capabilities utilizes a video camera.
40. A bicycle comprising a continuously variable transmission unit according to any one of the preceding Claims.
41. A tricycle comprising a continuously variable transmission unit according to any one of the preceding Claims.
42. A cycle comprising a continuously variable transmission unit according to any one of the preceding Claims.
43. A continuously variable transmission unit substantially as described herein with reference to Figures 1 to 16 of the accompanying drawings.