EP1516411A1 - A generator for a bicycle - Google Patents

A generator for a bicycle

Info

Publication number
EP1516411A1
EP1516411A1 EP03756975A EP03756975A EP1516411A1 EP 1516411 A1 EP1516411 A1 EP 1516411A1 EP 03756975 A EP03756975 A EP 03756975A EP 03756975 A EP03756975 A EP 03756975A EP 1516411 A1 EP1516411 A1 EP 1516411A1
Authority
EP
European Patent Office
Prior art keywords
rotor
generator according
generator
drive wheel
rotating member
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP03756975A
Other languages
German (de)
French (fr)
Inventor
Troels Pedersen
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
REELIGHT APS
Original Assignee
REELIGHT APS
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by REELIGHT APS filed Critical REELIGHT APS
Publication of EP1516411A1 publication Critical patent/EP1516411A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
    • H02K7/18—Structural association of electric generators with mechanical driving motors, e.g. with turbines
    • H02K7/1807—Rotary generators
    • H02K7/1846—Rotary generators structurally associated with wheels or associated parts
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K21/00—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets
    • H02K21/12—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets
    • H02K21/24—Synchronous motors having permanent magnets; Synchronous generators having permanent magnets with stationary armatures and rotating magnets with magnets axially facing the armatures, e.g. hub-type cycle dynamos
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K7/00—Arrangements for handling mechanical energy structurally associated with dynamo-electric machines, e.g. structural association with mechanical driving motors or auxiliary dynamo-electric machines
    • H02K7/10—Structural association with clutches, brakes, gears, pulleys or mechanical starters
    • H02K7/116—Structural association with clutches, brakes, gears, pulleys or mechanical starters with gears

Definitions

  • the present invention relates to a generator to be driven by a moving member of a bicycle.
  • the invention relates to a simple and reliable bicycle generator which is capable of delivering sufficient electrical output for a head and a tail light even at relatively low rotational speed of the driving member of the bicycle.
  • a generator attached between the frame and a wheel of a bicycle to generate electrical energy for consuming devices such as a head or tail light.
  • synchronous generators comprising one single-phase wire coil of a stator and a corresponding permanent magnet of a rotor have been assembled into dynamo units for attachment to a front fork or on similar locations where the dynamo can be driven by the rotation of a bicycle wheel.
  • the rotor part is driven via a drive roll connected to or pressed against a wheel or tire of the bicycle.
  • US 5,895,991 suggests using a generator with a rotor coupled to a wheel via a gear allowing the rotor to rotate faster than the wheel.
  • the present invention relates to a generator for a bicycle having a frame and a rotating member, the rotating member having a hub axis, the generator comprising a rotor, rotatable in relation to a stator, and a transmission
  • SUBSTITUTE SHEET fixedly securable to the rotating member for transmitting rotational power from the rotating member to the rotor, the transmission being adapted to transmit the rotational power so that the rotor is rotatable at a speed faster than that of the rotating member, wherein a first part is one of the stator and the rotor and comprises a plurality of magnetic pole sets.
  • a generator which can be connected to and driven by a wheel or crank of the bicycle and which can provide an output in the size of 3-6 Watt which is sufficient for a head and tail light without extensive gearing. It has been found that an amount of 8-20 pole sets (north and south poles), i.e. 16-40 poles and a gearing rate between 1:3 and 1: 10 such as 1:7 between the rotational speed of a normal bicycle wheel and the rotational speed of the rotor is sufficient for powering head and tail lights in accordance with typical national rules, e.g. 3 W.
  • the other part of the rotor or stator may be provided with a plurality, e.g. 8-12, of individually wound windings.
  • a larger number of pole sets e.g. 20-40 pole sets, i.e. 40-80 poles may be used.
  • the gearing rate may be raised to the range between 1:7 and 1:20 such as 1: 14.
  • the rotor comprises the pole sets and the stator comprises one or more windings.
  • the rotor and/or the stator may be formed by laminating a plurality of individually isolated layers of a magnetically conductive material, e.g. iron or it could be sintered ferrite or polymer bounded iron dust. In some variants this material may be soft magnetic alloys specially designed to have high magnetic conductivity or a low specific resistance. Since the rotor or the stator comprises a plurality of pole sets, the transmission can be made in a relatively simple manner, e.g.
  • the second drive wheel can be driven either via a belt or via meshing teeth of the drive wheels (gear wheels) or even via frictional resistance between peripheral surfaces of the two drive wheels.
  • the rotor may be integrated with the second drive wheel.
  • the integrated rotor and drive wheel may comprise a gear wheel fastened to a plate which carries a ring-shaped magnet or a plurality of magnets arranged along an outer peripheral edge of the plate.
  • the gear wheel could be made from a light weight and magnetically non- conductive material, e.g. nylon, Teflon, Acetal etc.
  • the plate could preferably be made from a magnetically conductive material to improve the magnetic field from the magnet(s).
  • the ring shaped magnet could be arranged in contact with an additional element of a magnetically conductive material. The additional element could be arranged coaxially inside the ring-shaped magnet and thus improve the magnetic field.
  • the rotor could be rotated by the rotating member of the bicycle e.g. via a cam fastened directly to the rotor or to the first drive wheel.
  • the cam could engage the rotating member, e.g. a wheel or a crank shaft of the bicycle.
  • the rotor could also be rotated by the rotating member of the bicycle via a magnetic field between the rotating member of the bicycle and the generator, e.g. via a magnet fastened to the first drive wheel for creation of a force between the first drive wheel and a magnetic conductive material of the rotating member of the bicycle, or a magnet could be fastened to the rotating member of the bicycle for creation of a force between the rotating member and a magnetic conductive material fastened to the rotor or to the first drive wheel.
  • the first drive wheel is attached coaxially to the hub of the rotating member and the rotating power is transferred, e.g. via a cam arranged on either the rotating member or on the first drive wheel.
  • the first drive wheel is thereby driven at the rotational speed of this member.
  • the second drive wheel can be coupled directly to the rotor for driving the rotor at a rotational speed equal to the rotational speed of the second drive wheel.
  • the users of dynamos for a bicycle experience that there is a disproportion between the generated output and the necessity for light.
  • it is a well known drawback of the known generators that cycling with very low speed generates too little energy to power the lights of the bicycle sufficiently.
  • cycling with very high speed causes the generator to produce more energy than needed and thus to consume more energy than necessary.
  • the magnetic pole sets of the generator according to the present invention may be electrically magnetised. Whenever there is a need for more electrical energy with unchanged rotational speed, the poles can be magnetised stronger, vice versa.
  • the generator may comprise a control circuit allowing the user to control the magnetism of the pole sets and the control circuit may be adapted to automatically control the magnetism based on a desired fixed output, e.g. 3 W for driving a head lamp.
  • a desired fixed output e.g. 3 W for driving a head lamp.
  • the use of a drive belt in relation to meshing teeth of the drive wheels has the advantage that the noise developed by the transmission can be reduced.
  • some drive belts require tension means to be used, e.g. a spring loaded roll which presses radially against the belt and thus ensures a minimum pressure between the drive belt and the drive wheels.
  • tension means e.g. a spring loaded roll which presses radially against the belt and thus ensures a minimum pressure between the drive belt and the drive wheels.
  • the first and the second drive wheel can be attached radially movably in relation to each other.
  • the drive belt is a toothed belt for a tooth belt drive or a belt which is wedge shaped in a cross-sectional view.
  • the drive wheels could be made from a steel material or from nylon, Acetal, Teflon or any similar plastic material.
  • the transmission could also comprise a train of gears.
  • first and second drive wheels are toothed drive wheels, they may, in order to reduce noise, be made with helical teeth.
  • first and second drive wheels are toothed drive wheels, they may have tooth profiles which differ from traditionally tooth-profiles in order to reduce noise.
  • 8-20 sets of poles combined with a gear rate of 3-7 between a bicycle wheel and the rotor may be sufficient for generating the electrical power necessary for powering a head and/or a tail light.
  • a gear exchange rate between 2 and 15, i.e. a gear which causes the rotor to rotate 2-15 times faster than the rotating member is sufficient for a bicycle, even when the crank, which typically has a lower rotational speed than that of the wheels, is chosen as the rotating member.
  • a gear exchange rate of this size can easily be made in a single gear step by means of two drive wheels.
  • the generator may have coupling means for coupling and decoupling the transmission between the rotating member and the rotor.
  • the decoupling can be performed by moving one of the wheels in a radial direction away from the other one of the wheels so that the teeth thereof disengage.
  • the power is transmitted from one wheel to the other via a belt
  • the decoupling can be performed by moving one of the wheels in a redial direction towards the other one of the wheels.
  • the belt can be slackened sufficiently to ensure that it can no longer transfer the power.
  • one of the wheels can be moved radially away from the other one of the wheels until the belt tightens against the peripheral surfaces of the wheels and starts to transfer power there between.
  • the generator may comprise a control, e.g. comprising a wire leading from the generator to a handgrip in the vicinity of or attached to the handle bar or to the bicycle frame.
  • the generator may be housed in a ring- shaped chassis comprising an opening of a size allowing the chassis to be attached to the frame around the hub axis.
  • the housing may be attached to the free end of the fork holding the front or rear wheel of the bicycle.
  • the opening can be arranged to encircle the centre axis of the wheel hub and the rotation of the wheel can be transferred to the first of the rotating drive wheels via a direct fixation of the drive wheel to the bicycle wheel or the bicycle wheel may be formed with an axially outwardly extending cam arranged to push a corresponding notch or edge of the drive wheel.
  • Rotation of the rotating member of the bicycle may also be transferred to the generator via a magnetic coupling between the member of the bicycle and the generator.
  • the electrical output from the generator may preferably comprise an electrical connector arranged in the housing shielded from moist and dirt.
  • Fig. 1 shows a schematic view of the generator according to the invention
  • Fig. 2 shows an alternative embodiment of the generator according to the invention
  • FIGs. 3 and 4 show schematic views of the generator attached to a bicycle
  • Fig. 5 shows a rotor with a plurality of magnets
  • Fig. 6 shows a rotor with a ring-shaped magnet
  • Fig. 7 shows an embodiment of the invention, wherein a centre part of the rotor is made from a magnetic conductive material, and
  • Fig. 8 shows a generator coupled to a rotating member of the bicycle via a gear connection comprising toothed wheels.
  • the generator comprises a housing 1 inclosing a stator 2 and a rotor 3, the rotor is connected to a drive wheel via a drive axle 4 and comprises a plurality of sets of magnetic poles 5, 6 arranged alternately north and south poles along the entire outer periphery of the rotor.
  • the core 7 of the rotor is preferably made from a magnetically conductive material such as iron or any other metallic composition.
  • the stator is made with a winding 8 from which winding electrical cables 9 transfer the generated electrical power to an outlet terminal 10, when the rotor is rotated around the centre axis 11.
  • Fig. 2 shows a housing 21 inclosing a stator 22 and a rotor 23.
  • the stator can be made with a plurality of individually wound windings 24 arranged in fixtures 25.
  • the windings are connected to one and the same cable 26 transferring the generated electrical power to the terminal 27.
  • the generator 31 has been attached to the frame, e.g. to the front fork 32 of a bicycle.
  • the first drive wheel 33 of the generator is attached coaxially in relation to the hub axle 34 of the crank or to the hub axle of one of the wheels of the bicycle.
  • the first drive wheel is driven by the wheel via a cam 35 fastened to the drive wheel and extending in the axial direction of the hub between the spokes 36 of the wheel. In that way, the first drive wheel is driven directly with the same rotational speed as the bicycle wheel. From the first drive wheel, the rotational power is transferred to a second drive wheel 37 via a drive belt 38.
  • the first and second drive wheels have toothed outer peripheral surfaces 39, 40 enhancing the
  • the drive belt may be a toothed belt made to engage the toothed surface of the drive wheels.
  • the first drive wheel 43 of the generator may be driven directly by the hub 42 of one of the wheels of the bicycle. From the first wheel, the power is transferred to the second drive wheel 44 via frictional resistance between the two wheels along their outer peripheral surfaces 45, 46.
  • the drive wheels may be formed with meshing teeth as gear-wheels.
  • Fig. 5 shows a rotor comprising a gear wheel 50 attached to a plate 51 which plate carries a plurality of magnets 52-58.
  • the magnets are fastened to the plate along the outer peripheral part thereof.
  • the rotor is carried by a bearing for rotation around the centre axis 59.
  • the gear wheel 50 is made from nylon, Teflon, Acetal etc.
  • the plate 51 is made from a magnetically conductive material.
  • the magnets may be adhered to the plate e.g. during a moulding process wherein the magnets are arranged in a mould of an injection moulding machine or the magnets may be glued to the surface of the plate.
  • Fig. 6 shows a rotor similar to the rotor of Fig. 5 wherein the magnet 63 is a ring-shaped magnet polarised to form a plurality of pole-pairs 64, 65 along the periphery.
  • the ring- shaped magnet is fastened to a plate and a gear wheel of a kind and in a way as described under Fig. 5, i.e. the plate 62 is made from a magnetically conductive material to improve the magnetic field.
  • Fig. 7 shows a rotor comprising a ring-shaped magnet or a plurality of magnets with north and south poles 72, 73 arranged peripherally in contact with a magnetically conductive part 74.
  • the rotor is rotated around the centre axis 75 via the gear wheel 76.
  • Fig. 8 shows a hub 81 connected to a first drive wheel 82 being toothed wheel.
  • the first drive wheel meshes with the second toothed drive wheel 83 which is connected to the rotor of the generator 84 via the drive shaft 85.
  • the generator 84 could be displaceable mounted to the hub axle 86 or to the front or rear fork of the bicycle so that the toothed wheels can be connected and disconnected, respectively.
  • the position of the generator in relation to the first drive wheel 82 could be controlled via a handle fixed to the handlebar of the bicycle.

Abstract

The present invention relates to a generator to be driven by a driving member of a bicycle. The generator according to the invention can be made with a simple and reliable design and with a performance which is sufficient for a head and tail light even at low rotational speed of the driving member. Accordingly, the generator can be driven not only by the wheel of the bicycle but also by a crank hub axle. The generator is provide with a combination between a transmission which causes a rotor to rotate faster than the rotating member of the bicycle and a rotor-stator arrangement comprising a plurality of magnet pole sets and windings.

Description

A GENERATOR FOR A BICYCLE
INTRODUCTION
The present invention relates to a generator to be driven by a moving member of a bicycle. In particular, the invention relates to a simple and reliable bicycle generator which is capable of delivering sufficient electrical output for a head and a tail light even at relatively low rotational speed of the driving member of the bicycle.
BACKGROUND OF THE INVENTION
It is known to use a generator attached between the frame and a wheel of a bicycle to generate electrical energy for consuming devices such as a head or tail light. For that purpose, synchronous generators comprising one single-phase wire coil of a stator and a corresponding permanent magnet of a rotor have been assembled into dynamo units for attachment to a front fork or on similar locations where the dynamo can be driven by the rotation of a bicycle wheel. In the design of generators for bicycles, it is desired to keep the construction relatively simple and to keep the weight low. In some of the known dynamos, the rotor part is driven via a drive roll connected to or pressed against a wheel or tire of the bicycle. The rolls which are biased against the rubber tire often generate noise, and by accident, the rotor may even tilt into the spokes of the wheel thereby blocking rotation thereof. In more advanced generators, the rotor part is fixed to and driven directly by the rotation of the wheel. Since, however, the generated output from the generator is proportional to the speed of the rotor in relation to the stator, it is difficult to obtain sufficient electrical energy when driving at low speed.
In order to improve the efficiency of the known generators, US 5,895,991 suggests using a generator with a rotor coupled to a wheel via a gear allowing the rotor to rotate faster than the wheel.
Even though a gear may improve the output from the generator, extensive gearing has some drawbacks. First of all, the loss due to the mechanical gearing is proportional with the gear rate. Secondly, making of gears with a large gearing ratio complicates the construction of the generator and as a consequence, the price will be increased while the reliability may be impaired. Thirdly, a large gearing ratio can impair the weight of the dynamo, and finally, the noise developed by the generator depends on the speed of the rotor and on the ratio of gearing.
DESCRIPTION OF THE INVENTION
It is an object of the present invention to provide a bicycle generator with a simple and reliable design and which is capable of generating a satisfactory amount of electrical energy for a head light. Accordingly, the present invention, relates to a generator for a bicycle having a frame and a rotating member, the rotating member having a hub axis, the generator comprising a rotor, rotatable in relation to a stator, and a transmission
SUBSTITUTE SHEET fixedly securable to the rotating member for transmitting rotational power from the rotating member to the rotor, the transmission being adapted to transmit the rotational power so that the rotor is rotatable at a speed faster than that of the rotating member, wherein a first part is one of the stator and the rotor and comprises a plurality of magnetic pole sets.
Due to combination between the plurality of pole sets of either the rotor or the stator and the transmission which increases the rotational speed of the rotor in relation to the rotating member of the bicycle, a generator is provided which can be connected to and driven by a wheel or crank of the bicycle and which can provide an output in the size of 3-6 Watt which is sufficient for a head and tail light without extensive gearing. It has been found that an amount of 8-20 pole sets (north and south poles), i.e. 16-40 poles and a gearing rate between 1:3 and 1: 10 such as 1:7 between the rotational speed of a normal bicycle wheel and the rotational speed of the rotor is sufficient for powering head and tail lights in accordance with typical national rules, e.g. 3 W. Edison type light bulbs in both lights. In order further to improve the output from the generator, the other part of the rotor or stator may be provided with a plurality, e.g. 8-12, of individually wound windings. If the generator is designed to be driven by a bicycle element rotating at a relatively low speed, e.g. to be driven by the crank shaft, a larger number of pole sets, e.g. 20-40 pole sets, i.e. 40-80 poles may be used. Correspondingly, the gearing rate may be raised to the range between 1:7 and 1:20 such as 1: 14.
In order to avoid complicating transfer of electricity from a housing for the generator to the rotating rotor, it is an advantage to make a generator wherein the rotor comprises the pole sets and the stator comprises one or more windings. The rotor and/or the stator may be formed by laminating a plurality of individually isolated layers of a magnetically conductive material, e.g. iron or it could be sintered ferrite or polymer bounded iron dust. In some variants this material may be soft magnetic alloys specially designed to have high magnetic conductivity or a low specific resistance. Since the rotor or the stator comprises a plurality of pole sets, the transmission can be made in a relatively simple manner, e.g. via a single gear wherein a first drive wheel with one radial size drives a second drive wheel with another radial size. The second drive wheel can be driven either via a belt or via meshing teeth of the drive wheels (gear wheels) or even via frictional resistance between peripheral surfaces of the two drive wheels.
In order to reduce the weight of the generator or in general to keep the design simple, the rotor may be integrated with the second drive wheel. As an example, the integrated rotor and drive wheel may comprise a gear wheel fastened to a plate which carries a ring-shaped magnet or a plurality of magnets arranged along an outer peripheral edge of the plate. The gear wheel could be made from a light weight and magnetically non- conductive material, e.g. nylon, Teflon, Acetal etc. The plate could preferably be made from a magnetically conductive material to improve the magnetic field from the magnet(s). In order further to improve the magnetic field, the ring shaped magnet could be arranged in contact with an additional element of a magnetically conductive material. The additional element could be arranged coaxially inside the ring-shaped magnet and thus improve the magnetic field.
SUBSTITUTE SHEET The rotor could be rotated by the rotating member of the bicycle e.g. via a cam fastened directly to the rotor or to the first drive wheel. The cam could engage the rotating member, e.g. a wheel or a crank shaft of the bicycle. The rotor could also be rotated by the rotating member of the bicycle via a magnetic field between the rotating member of the bicycle and the generator, e.g. via a magnet fastened to the first drive wheel for creation of a force between the first drive wheel and a magnetic conductive material of the rotating member of the bicycle, or a magnet could be fastened to the rotating member of the bicycle for creation of a force between the rotating member and a magnetic conductive material fastened to the rotor or to the first drive wheel.
Alternatively, the first drive wheel is attached coaxially to the hub of the rotating member and the rotating power is transferred, e.g. via a cam arranged on either the rotating member or on the first drive wheel. The first drive wheel is thereby driven at the rotational speed of this member. The second drive wheel can be coupled directly to the rotor for driving the rotor at a rotational speed equal to the rotational speed of the second drive wheel.
Sometimes, the users of dynamos for a bicycle experience that there is a disproportion between the generated output and the necessity for light. As an example, it is a well known drawback of the known generators that cycling with very low speed generates too little energy to power the lights of the bicycle sufficiently. On the other hand, cycling with very high speed causes the generator to produce more energy than needed and thus to consume more energy than necessary. In order to improve the efficiency and to allow a better control of the output of the generator, the magnetic pole sets of the generator according to the present invention may be electrically magnetised. Whenever there is a need for more electrical energy with unchanged rotational speed, the poles can be magnetised stronger, vice versa. For that purpose, the generator may comprise a control circuit allowing the user to control the magnetism of the pole sets and the control circuit may be adapted to automatically control the magnetism based on a desired fixed output, e.g. 3 W for driving a head lamp. By the use of electromagnetism, one single pole set of the rotor or stator may even be sufficient for driving the electrical appliances of the bicycle.
The use of a drive belt in relation to meshing teeth of the drive wheels has the advantage that the noise developed by the transmission can be reduced. On the other hand, some drive belts require tension means to be used, e.g. a spring loaded roll which presses radially against the belt and thus ensures a minimum pressure between the drive belt and the drive wheels. In order to tighten or slacken the drive belt, respectively, one or both of the first and the second drive wheel can be attached radially movably in relation to each other. In a preferred embodiment, the drive belt is a toothed belt for a tooth belt drive or a belt which is wedge shaped in a cross-sectional view. The drive wheels could be made from a steel material or from nylon, Acetal, Teflon or any similar plastic material. The transmission could also comprise a train of gears.
SUBSTITUTE SHEET If the first and second drive wheels are toothed drive wheels, they may, in order to reduce noise, be made with helical teeth.
If the first and second drive wheels are toothed drive wheels, they may have tooth profiles which differ from traditionally tooth-profiles in order to reduce noise.
As mentioned earlier, 8-20 sets of poles combined with a gear rate of 3-7 between a bicycle wheel and the rotor may be sufficient for generating the electrical power necessary for powering a head and/or a tail light. In general, a gear exchange rate between 2 and 15, i.e. a gear which causes the rotor to rotate 2-15 times faster than the rotating member, is sufficient for a bicycle, even when the crank, which typically has a lower rotational speed than that of the wheels, is chosen as the rotating member. A gear exchange rate of this size can easily be made in a single gear step by means of two drive wheels.
In order to allow the generator to be decoupled, e.g. at daytime when no lights are necessary, the generator may have coupling means for coupling and decoupling the transmission between the rotating member and the rotor. If the drive wheels are formed as meshing toothed wheels, the decoupling can be performed by moving one of the wheels in a radial direction away from the other one of the wheels so that the teeth thereof disengage. If the power is transmitted from one wheel to the other via a belt, the decoupling can be performed by moving one of the wheels in a redial direction towards the other one of the wheels. Thereby, the belt can be slackened sufficiently to ensure that it can no longer transfer the power. Whenever there is a need for electrical power, one of the wheels can be moved radially away from the other one of the wheels until the belt tightens against the peripheral surfaces of the wheels and starts to transfer power there between.
For the purpose of coupling and decoupling the generator, respectively, the generator may comprise a control, e.g. comprising a wire leading from the generator to a handgrip in the vicinity of or attached to the handle bar or to the bicycle frame.
For an easy fitting of the generator to a bicycle, the generator may be housed in a ring- shaped chassis comprising an opening of a size allowing the chassis to be attached to the frame around the hub axis. As an example, the housing may be attached to the free end of the fork holding the front or rear wheel of the bicycle. The opening can be arranged to encircle the centre axis of the wheel hub and the rotation of the wheel can be transferred to the first of the rotating drive wheels via a direct fixation of the drive wheel to the bicycle wheel or the bicycle wheel may be formed with an axially outwardly extending cam arranged to push a corresponding notch or edge of the drive wheel.
Rotation of the rotating member of the bicycle may also be transferred to the generator via a magnetic coupling between the member of the bicycle and the generator.
The electrical output from the generator may preferably comprise an electrical connector arranged in the housing shielded from moist and dirt.
SUBSTITUTE SHEET DETAILED DESCRIPTION OF THE INVENTION
In the following, the invention will be described in further details with reference to the drawing in which:
Fig. 1 shows a schematic view of the generator according to the invention,
Fig. 2 shows an alternative embodiment of the generator according to the invention,
Figs. 3 and 4 show schematic views of the generator attached to a bicycle, and
Fig. 5, shows a rotor with a plurality of magnets,
Fig. 6 shows a rotor with a ring-shaped magnet, and
Fig. 7 shows an embodiment of the invention, wherein a centre part of the rotor is made from a magnetic conductive material, and
Fig. 8 shows a generator coupled to a rotating member of the bicycle via a gear connection comprising toothed wheels.
As shown in Fig. 1, the generator comprises a housing 1 inclosing a stator 2 and a rotor 3, the rotor is connected to a drive wheel via a drive axle 4 and comprises a plurality of sets of magnetic poles 5, 6 arranged alternately north and south poles along the entire outer periphery of the rotor. The core 7 of the rotor is preferably made from a magnetically conductive material such as iron or any other metallic composition. The stator is made with a winding 8 from which winding electrical cables 9 transfer the generated electrical power to an outlet terminal 10, when the rotor is rotated around the centre axis 11.
Fig. 2 shows a housing 21 inclosing a stator 22 and a rotor 23. As shown in Fig. 2, the stator can be made with a plurality of individually wound windings 24 arranged in fixtures 25. In this case, the windings are connected to one and the same cable 26 transferring the generated electrical power to the terminal 27.
In Fig. 3, the generator 31 has been attached to the frame, e.g. to the front fork 32 of a bicycle. The first drive wheel 33 of the generator is attached coaxially in relation to the hub axle 34 of the crank or to the hub axle of one of the wheels of the bicycle. In the embodiment of Fig. 3, the first drive wheel is driven by the wheel via a cam 35 fastened to the drive wheel and extending in the axial direction of the hub between the spokes 36 of the wheel. In that way, the first drive wheel is driven directly with the same rotational speed as the bicycle wheel. From the first drive wheel, the rotational power is transferred to a second drive wheel 37 via a drive belt 38. As shown, the first and second drive wheels have toothed outer peripheral surfaces 39, 40 enhancing the
SUBSTITUTE SHEET frictional force against the drive belt. The drive belt may be a toothed belt made to engage the toothed surface of the drive wheels.
As shown in Fig. 4, wherein the generator is attached to a frame 41 of the bicycle, the first drive wheel 43 of the generator may be driven directly by the hub 42 of one of the wheels of the bicycle. From the first wheel, the power is transferred to the second drive wheel 44 via frictional resistance between the two wheels along their outer peripheral surfaces 45, 46. Alternatively (not shown), the drive wheels may be formed with meshing teeth as gear-wheels.
Fig. 5 shows a rotor comprising a gear wheel 50 attached to a plate 51 which plate carries a plurality of magnets 52-58. The magnets are fastened to the plate along the outer peripheral part thereof. The rotor is carried by a bearing for rotation around the centre axis 59. The gear wheel 50 is made from nylon, Teflon, Acetal etc. In order to improve the magnetic field, the plate 51 is made from a magnetically conductive material. The magnets may be adhered to the plate e.g. during a moulding process wherein the magnets are arranged in a mould of an injection moulding machine or the magnets may be glued to the surface of the plate.
Fig. 6 shows a rotor similar to the rotor of Fig. 5 wherein the magnet 63 is a ring-shaped magnet polarised to form a plurality of pole-pairs 64, 65 along the periphery. The ring- shaped magnet is fastened to a plate and a gear wheel of a kind and in a way as described under Fig. 5, i.e. the plate 62 is made from a magnetically conductive material to improve the magnetic field.
Fig. 7 shows a rotor comprising a ring-shaped magnet or a plurality of magnets with north and south poles 72, 73 arranged peripherally in contact with a magnetically conductive part 74. The rotor is rotated around the centre axis 75 via the gear wheel 76.
Fig. 8 shows a hub 81 connected to a first drive wheel 82 being toothed wheel. The first drive wheel meshes with the second toothed drive wheel 83 which is connected to the rotor of the generator 84 via the drive shaft 85. The generator 84 could be displaceable mounted to the hub axle 86 or to the front or rear fork of the bicycle so that the toothed wheels can be connected and disconnected, respectively. The position of the generator in relation to the first drive wheel 82 could be controlled via a handle fixed to the handlebar of the bicycle.
SUBSTITUTE SHEET

Claims

1. A generator for a bicycle having a frame and a rotating member, the generator comprising a rotor, rotatable in relation to a stator, a transmission fixedly securable to the rotating member for transmitting rotational power from the rotating member to the rotor, the transmission being adapted to transmit the rotational power so that the rotor is rotatable at a speed faster than that of the rotating member, wherein a first part is one of the stator and the rotor and comprises a plurality of pole sets.
2. A generator according to claim 1, wherein a second part being the other one of either the stator or the rotor comprises a plurality of sets of individually wound windings.
3. A generator according to claim 1 or 2, wherein the first part comprises in the range of 8-20 sets of poles.
4. A generator according to claims 1-3, wherein the second part comprises in the range of 4-20 sets of individually wound windings.
5. A generator according to any of the preceding claims, wherein the transmission comprises a first drive wheel driving a second drive wheel, the first drive wheel driving with the rotational speed of the rotating member, and the second drive wheel being coupled directly to the rotor for driving the rotor at a rotational speed equal to the rotational speed of the second drive wheel.
6. A generator according to claims 1-5, wherein the first drive wheel drives the second drive wheel via a single drive belt e.g. a tooth belt or a smooth belt made of rubber which in a cross sectional view is circular or V-shaped.
7. A generator according to claim 5, wherein the first and the second drive wheels are gear wheels and wherein the first drive wheel drives the second drive wheel via a single gear mesh.
8. A generator according to claims 5-7 wherein the rotor is integrated with the second drive wheel.
9. A generator according to claim 8, wherein the integrated rotor and drive wheel comprises a gear wheel made from a material which is unable to conduct magnetism and a ring-shaped magnet fastened thereto.
10. A generator according to claim 9, wherein the ring-shaped magnet is in contact with an element of a magnetically conductive material, the element being arranged coaxially inside the ring-shaped magnet.
SUBSTITUTE SHEET
11. A generator according to any of the preceding claims, wherein the rotor is rotated by a cam arranged on the generator to engage a spoke of a bicycle wheel.
12. A generator according to any of the preceding claims, wherein the rotor is rotated by a magnetic field between the rotating member of the bicycle and the generator.
13. A generator according to any of the preceding claims, wherein the transmission is adapted to transmit the rotational power so that the rotor is rotatable at a speed which is between 2 and 10 times faster than that of the rotating member.
14. A generator according to any of the preceding claims, further comprising coupling means for coupling and decoupling of the transmission between the rotating member and the rotor.
15. A generator according to claim 14, wherein the coupling means comprises a control for radially disposing the first drive wheel in relation to the second drive wheel.
16. A generator according to any of the preceding claims, wherein the rotor and stator is housed in a ring-shaped chassis comprising an opening of a size allowing the chassis to be attached to the frame around a hub axis of the rotating member.
17. A generator according to any of the preceding claims, wherein the rotor is laminated from a plurality of individually isolated plates of a magnetically conductive material.
18. A generator according to any of the preceding claims, wherein the stator is laminated from a plurality of individually isolated plates of a magnetically conductive material.
19. A generator according to any of the preceding claims, wherein the magnetic poles are polarised electrically.
20. A generator according to claim 19, further comprising a signal processing unit adapted to control the electrical polarisation of the magnetic poles based on the electrical output from the generator.
21. A generator according to claim 20, wherein the signal processing unit is adapted to control the electrical polarisation of the magnetic poles based on the rotational speed of the rotor.
22. A generator according to claim to any preceding claims, wherein the generator is attached to an electric circuit or a Zener diode to limit the produced output voltage.
23. A generator according to claim 22, wherein the voltage is limited to 6 V.
SUBSTITUTE SHEET
EP03756975A 2002-06-06 2003-06-06 A generator for a bicycle Withdrawn EP1516411A1 (en)

Applications Claiming Priority (9)

Application Number Priority Date Filing Date Title
DKPA200200857 2002-06-06
DK200200857 2002-06-06
DKPA200200885 2002-06-11
DK200200885 2002-06-11
DKPA200300165 2003-02-06
DK200300165 2003-02-06
DK200300645 2003-04-29
DKPA200300645 2003-04-29
PCT/DK2003/000376 WO2003105314A1 (en) 2002-06-01 2003-06-06 A generator for a bicycle

Publications (1)

Publication Number Publication Date
EP1516411A1 true EP1516411A1 (en) 2005-03-23

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ID=29740898

Family Applications (1)

Application Number Title Priority Date Filing Date
EP03756975A Withdrawn EP1516411A1 (en) 2002-06-06 2003-06-06 A generator for a bicycle

Country Status (3)

Country Link
EP (1) EP1516411A1 (en)
AU (1) AU2003232163A1 (en)
WO (1) WO2003105314A1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8075168B1 (en) 2008-01-02 2011-12-13 Carl Lee Shoolman Bicycle safety lights for day and night
WO2013160100A2 (en) * 2012-04-24 2013-10-31 Aktiebolaget Skf Bearing power generating configuration

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19707243A1 (en) * 1997-02-25 1998-08-27 Stephan Walter Dynamo light machine especially for bicycle
DE19720301A1 (en) * 1997-05-15 1998-11-19 Sram De Gmbh Electricity generator for bicycles
US5874792A (en) * 1997-06-10 1999-02-23 Industrial Technology Research Institute Bicycle generator

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO03105314A1 *

Also Published As

Publication number Publication date
AU2003232163A1 (en) 2003-12-22
WO2003105314A1 (en) 2003-12-18

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