GB2319755A - Cycle with wheel hub mounted electric motor which generates electricity on braking - Google Patents

Abstract

A cycle comprises an electric motor (see figs 3 and 5) mounted in wheel hub 5 and controlled by a control unit 2 which is mechanically interlocked with drive lever 1 and brake lever 3. At a standstill and before a pre-set speed is reached, speed sensor 7, 8 prevents the motor from assisting in driving the cycle. After this speed has been exceeded the speed sensor 7, 8, via the control unit 2, activates power assistance the level of which is controlled by drive lever 1. Operating brake lever 3 retards the cycle by braking either wheel and initiates electricity generation, by the motor, which is used to re-charge a battery (19, fig 6). The level of re-charge is regulated by control unit 2. A battery case contains, for example, a fuse, charging socket, battery condition indicator and the necessary cabling (see fig 6). A milometer/speedometer indicates an operating stage of speed sensor 7, 8 so that automatic control of drive assist and/or retard/re-charge is selectable. The milometer/speedometer may be built into the battery case or the control unit 2.

Description

POWER ASSISTED CYCLE This invention relates to a Power Assisted Cycle using an Electric Motor together with its Controls.

Cycles are probably universally known as a form of transport and there are many interpretations, involving various forms of construction, design and drive. The most widely used means of drive being manual. There are some evident draw-backs to their use, such as other traffic dangers and energy requirements.

Taking traffic dangers first. the Government are actively involved with tackling this problem, by the introduction of specific cycle tracks throughout the country.

In tackling the energy requirement problem it will be necessary to address this in a manner which does not severely limit its applications, both from the physical and expense aspects.

It has long been recognised that some means of power assistance would encourage/enable the more widespread use of the cycle. This in itself would be heralded as a 'step in the right direction', from an environmental point of view.

The present invention provides electrical assistance via a motor and battery with relevant controls to enable; drive, re-charge and retard. It takes safety, efficiency of operation, limits of bulk, manufacturing problems, together with expense of product, as its main features of design.

The main features are: Integration of the motor into the wheel hub. (Front or rear).

Variations of this motor/hub 5 integration.

Battery of optimum design, size, capacity and voltage to give best safety, bulk, range, function and expense combination.

Frame to adequately support this battery in the most suitable location.

Provision of speed sensor with outputs for relevant controls.

Manual interlocked controls for selection of and level of, drive assistance or re-charge/retard.

Optional integration of manual controls with mechanical braking.

Electrical/electronic means of enabling required controls of both drive assistance and re-charge/retard levels.

Optional automatic control feature.

Indication of speed, mileage and battery state as required.

Casings of durable, weatherproof construction, with safety and aesthetic view points being addressed.

Bulk minimisation design.

Facilities for both on and off cycle re-charging of the battery.

A specific embodiment of the invention will now be described by way of example with reference to the accompanying drawings of which : Figure 1 illustrates an envisaged control lever arrangement with drive lever 1, control unit 2 and re-charge/retard operation integrated into brake lever 3. The mechanical brake control cable 4, having its usual function.

Figure 2 is a perspective view of the wheel hub 5, together with cabling 6 and frame attached detector 7, with spoke attached target 8, both components of the electronic speed sensor/control system.

Figure 3 shows cycle motor/hub 5 supported between cycle frame forks 10, (front or rear). Comprising of central locked armature 11, having a number of magnetic poles with attached brush gear 12 and duct for cabling 13. The bearings 14 which support the motor body 15, field coils 16, commutator 17 and wheel spoke rings 9.

An aperture with seal 18 is provided.

Figure 4 is another view of commutator.

Figure 5 shows typical cross section of motor/hub 5 with a multiple pole field 16.

Figure 6 illustrates one arrangement for battery 19, with enclosure consisting of sturdy, weatherproof, non-metallic case 20 with removeable top 21. The top 21 designed to house control electronics 22, fuse gear 23, 'on cycle' charging socket 24, with weatherproof cable entries 25. Weatherproof sealing cap over fuse gear 26 and further weatherproof cap with integral battery state indicator 27 designed to be accepted into the charging socket 24, are also shown.

Figure 7 indicates overall arrangement of component parts of this example of power assistance, including bracket arrangement 28 for attaching the battery case. The bicycle illustration in this figure has been used mainly because this form is probably universally recognised, not as a limitation on the use of this power assistance to any other form of cycle.

With reference to the illustrations for this example, an operation is now described: At standstill and prior to achieving a pre-set speed, the cycle power assistance/re-charge is prevented via the speed sensor arrangement.

On passing this relatively low speed the power assistance / re-charge is enabled by the speed sensor. Thence : Operation of the drive lever 1 will initially activate power assistance and subsequently control the level of this assistance via the control unit 2.

Operation of the retard/re-charge lever 3, will initially activate recharge/retard and subsequently control this, also via the control unit 2.

Falling below a further pre-set speed level, close to standstill, disables all forms of operation.

An arrangement in Figure 1 of control levers 1 and 3 gives full mechanical inter-locking, when combined with a common component within control unit 2, together with integration of recharge/retard into the mechanical braking system for any wheel.

For example front wheel re-charge/retard combined with either front or rear wheel mechanical breaking.

This being achieved by simple selection of which mechanical brake cable 4 is attached to lever 3.

The power unit utilised is the electric motor, of the construction having the commonly known property of being able to generate when being driven. Figure 2 represents the stream-lining of this motor into the conventional spoked wheel hub. The unconventional motor construction, for this example, is illustrated by figures 3 and 4, it has been made more feasible by the introduction of modern electronics and materials; whereby speed control is available from zero or very low speeds at relatively high torque's.

This particular example is shown to have electrically generated magnetic fields for both field 16 and armature 11 whereas the modern trend would indicate the use of permanent magnet construction for one of these. The reason for selecting this example is to explore design which would minimise the inherent retardation effect of the magnetic fields, when in de-energised state. (Free wheel rotation).

To facilitate cabling a duct 12 is formed axially along the shaft of the armature 11. This enables cabling to pass through the support bearing 14, owing to the shaft being locked into the cycle forks 10 by virtue of the locked armature construction.

Brush gear 12 is mounted to the fixed armature shaft and in this example a vertical commutator 17, is attached to the motor body 15, and this used to facilitate commutation of the field coils 16 current.

Motor or generator modes are achieved by known interaction of magnetic fields, associated with field 16 and/or armature 11 current directions. The direction of one of these currents being reversible by action of the control unit 2.

It can readily be seen, from figure 3, that this motor construction enables the field 16 with body 15 to revolve on the support bearings 14.

Attached to the motor body 15 are spoke rings 9 which form part of the recognised spoke wheel design. This enables the motor body 15 to become an integral part of the wheel using mutual bearings 14, thereby reducing final friction losses.

By utilising a suitable form of bearing 14 seating, both in the motor body 15 and on the armature 11 shaft, additional axial fastenings for the motor/hub 5 become unnecessary.

To facilitate brush replacement an aperture with suitable weatherproof seal 18 is provided.

Many other forms of motor/hub 5 construction have been explored, examples being the use of conventional motor, with or without gearing, and the introduction of a clutch. A bi-directional torque operated clutch bearing has been devised to minimise resistance to 'free wheel rotation', in some of these constructions.

Bearing gears have also been explored as a form of friction reduction and constructional aid when used in conjunction with other motor/hub 5 designs.

The battery 19 for power assistance is, by necessity of capacity, bulky and in order to prevent danger and protect this but maintain an aesthetic approach, together with a practical sighting, the design example, (for front wheel motor/hub 5) is illustrated as figure 6 with location and fixing shown in figure 7.

A sturdy non-metallic case of which the base 20 houses the high capacity, re-chargeable battery 19. (Or such other means available for storage of electrical energy). The case top 21 forms a weatherproof cover and connects the battery 19 when attached. This top 21 contains the necessary electronic equipment 22 and also provides 'on cycle' charging socket 24, with battery state indicator 27 fitted in a weatherproof cap.Also facilitates main fuse 23 replacement via a further weatherproof cap 26. Cable entries with seals 25 are provided.

The electronic/electrical circuit includes an electrical interlock to prevent inadvertent short circuit of battery 19.

The general layout for this example is indicated as figure 7. A sturdy bracket 28 supporting the bracket case 20 such that safety, cable flexing and balance are main considerations.

A milometer/ speedometer with indication of speed sensor operating stages is provided. These speed sensor operating stages are able to be so arranged such that automatic control of both drive assistance and/or retard/re-charge is selectable. The sighting of this unit (not illustrated) being dependant on practicality, from both the cyclist vision field and the cabling requirement aspects. Building this into the battery case top 21 or the control unit 2 would seem the most desirable locations, from these points of view.

Claims (15)

1 A cycle having electrical means by which to assist its movement forward separately or together with means to assist the retard of this movement, such electrical means being contained within/upon the cycle, with the power unit being integrated within a wheel of said cycle.

2 A cycle as claimed in claim 1 wherein control means are provided to select and regulate means and level of electrical assistance for forward motion and retard of this motion, this retard of motion being an inherent consequence of generation and thereby enabling re-charge of electrical supply means.

3 A cycle as claimed in claims 1 and 2 with said electrical assistance control means for forward or retard motion giving mechanical interlocking between such selections.

4 A cycle as claimed in claims 2 and 3 having said control means for selection and level of retard assistance integrated into a control means for operation of a mechanical brake of said cycle, this mechanical brake shall not necessarily be that applied to the power assisted wheel.

5 A cycle as claimed in claim 4 in which the electrical supply means is provided with durable, weatherproof case and necessary brackets to attach this securely to the cycle structure.

6 A cycle as claimed in claim 5 where said case is provided with removable top section, which in turn provides for sighting and protection of necessary electrical/electronic components.

7 A cycle as claimed as claimed in claim 6 wherein the said removable top section provides access for renewal of main fuse.

8 A cycle as claimed in claim 7 wherein said removable top section is provided with weatherproof cable entries for necessary cabling.

9 A cycle as claimed in claim 8 wherein said removable top section is provided with and access to a 'on cycle' charging socket.

10 A cycle as claimed in claim 9 wherein the said 'on cycle' charging socket is provided with the necessary circuit means to enable the weatherproof sealing cap to include a battery 'condition of charge' indicator and include said indicator.

11 A cycle as claimed in claim 10 provided with means by which the level of speed can be determined and related actions enabled.

12 A cycle as claimed in claim 11 wherein any determined speed level related action is definable by adjustment.

13 A cycle as claimed in claim 12 wherein defmed speed level related actions are provided with indication, such indication being of a form readily recognised by the cyclist.

14 A cycle as claimed in claim 13 wherein speed level related actions are provided such that automatic responses can be accessed from which control of drive assistance and/or retard/re-charge can be achieved by selection.

15 A cycle substantially as described herein with reference to figures 1-7 of the accompanying drawings.