EP4670235A1

EP4670235A1 - PLANAR COMMUTATOR WITH INVERSE FREEWHEEL AND ELECTRIC BICYCLE WITH IT

Info

Publication number: EP4670235A1
Application number: EP23924392.6A
Authority: EP
Inventors: Cenap Oguz Demir
Original assignee: Individual
Current assignee: Individual
Priority date: 2023-02-20
Filing date: 2023-02-20
Publication date: 2025-12-31
Also published as: WO2024177582A1

Abstract

An interoperating planar commutator (200) and an inverse freewheel (400) mechanism is proposed. The inverse freewheel (400) saves kinetic energy through momentum conservation via seamless mechanical decoupling of motors from loads in non-power assist mode in electric bicycles; and the planar commutator (200) energizes the rotor (300) powering the load through said inverse freewheel (400) via their common shaft (450) while improving production yield through low part count, disclike form fit and axial flux, for electric bicycles, mapping electrically parallel connected quantity N three-pole rotors (110) on a long shaft (120), into a 3 x N pole single rotor (300) on a short shaft (450). Both disclosures alleviate microcontroller, software, sensors and/or sophisticated electronics requirements. Disclosed invention specifically concerns energy saving, part reduction and form fitting improvements suitable for use in low-speed high torque applications such as electric bicycles.

Description

PLANAR COMMUTATOR WITH INVERSE FREEWHEEL AND ELECTRIC BICYCLE HAVING THE SAME

Technical Field of the Present Invention

The present disclosure generally relates to means of improving kinetic energy saving through momentum conservation via seamless mechanical decoupling of motors from their loads when in non-power assist mode such as in electric bicycles; and production yield in commutation through low part count for mechanically-switched and relatively high current, suitable for applications such as electric bicycles, that maps a group of electrically parallel connected quantity N three-pole rotors on a long shaft, into a 3 x N pole single rotor having a short shaft, arranged for motors and generators having the form fit of a disc, such as axial flux brushed DC machines. Disclosed invention more specifically concerns energy saving, part reduction and form fitting improvements suitable for use in low-speed high torque applications such as electric bicycles.

Background of the Present Invention

The three-pole motor, a member of the self-starting motors, comprise three coils/poles that are fixed to the shaft, in an arrangement with 120 degrees therebetween in the rotor section or armature, as well as a three segment commutator connecting the three common ends of the coils/poles and transferring current from a direct current (DC) power source through radial carbon brushes located on the stator and contacting the arc-wise bent segments of the commutator that are insulated from each other. The rotor rotates by means of torque created by the coils/poles in a certain order in the direction of rotation within the radial magnetic field formed between two permanent magnet poles within the stator.

As mentioned, as part of their structure, permanent magnet motors comprise pairs of magnets and multiple coils/poles that are arranged to overpass the magnets in close proximity and systematically energized to produce rotational motion. While the commutator is always located on the coil holding unit, based on the type of three-pole brushed motor, rotation may be engaged for either the coil holding unit being external to the stator which is named thereof an out-runner motor or internal to the stator which is named thereof an in-runner motor. Motors with salient poles such as the three-pole motor may also have a cogging torque since permanent magnets and coils/poles mutually exert direction changing magnetic forces on each other creating the said cogging effect which may result in vibration and noise.

US 20130002089A1 discloses a commutator with a tubular insulating core, a first slip ring fixed to the core, a plurality of first bars electrically connected to the first slip ring, a second slip ring fixed to the core, and a plurality of second bars electrically connected to the second slip ring. Said bars are alternately arranged at equally spaced intervals in the circumferential direction of the core. The first slip ring and the second slip ring are arranged on the same side of the first bars and the second bars. The first and second slip rings respectively comprise a contact surface that is substantially perpendicular to the axis of the commutator and is configured for contacting brushes.

CN106114057B discloses a split type flywheel rear-drive motor for an electric bicycle with a horizontally-provided main shaft, a rotatable hub housing, a ratchet detachably fixed to the hub housing, a sleeve outside a rotor and a flywheel toothed disc fixed to the sleeve. EP 1 237 235 discloses a planar carbon segment commutator comprising a commutator base of insulating material, said base having a rotational axis, front and rear surfaces, extending, at least in part, transversely to the rotational axis, and a plurality of first apertures extending through the base, a plurality of commutator terminals each of which comprises a terminal portion and a contact portion, the contact portion of each terminal extending through a respective first aperture in the base and being bent to lie against or in close proximity to the front surface of the base and the terminal portion of each terminal having two cutting edges for cutting insulation on a connector portion of a winding and a slot which in use straddles and grips said connector portion, and a plurality of carbon segments formed on the front surface of the base and over the contact portions, respectively, of the terminals.

Objects of the Present Invention

Primary object of the present invention is to provide a planar commutator suitable for use in axial flux DC motors for electric bicycles.

Another object of the present invention is to provide a planar commutator that co-planarly groups three-pole rotors in parallel physical planes and in parallel electrical connection along a shaft, around the rim of a single disc rotor to improve form fit for electric bicycles.

A further object of the present invention is to provide a planar commutator with few part-count that greatly simplifies control and power stage driver electronics for a DC motor it works in conjunction therewith.

A still further object of the present invention is to provide an inversely installed freewheel to couple mechanical power via the shaft into the transmission from the rotor or armature disc energized by the provided planar commutator.

A still further object of the present invention is to provide the same inversely installed freewheel, that decouples the rear wheel being driven by the DC motor and mechanically bypasses regenerative braking, thereby conserving bicycle momentum when the motor is not energized or in a non-power assisting mode.

Brief Description of the Present Invention

In a first aspect, there is provided a motor suitable for use in electric bicycles that simplifies commutation and saves kinetic energy. Said motor achieves these tasks with the aid of one planar commutator, and one freewheel apparatus whereby momentum of the bicycle is mostly conserved by bypassing regenerative braking during non-power assisting mode.

One aspect of the present disclosure, namely the planar commutator, ensures form-fit-function adaptability to a greater scale of potential applications, while first and foremost of it has been devised for electric bicycles. Said planar commutator structure also achieves longevity during high rate of power transfer suitable for electric bicycles and simplifies the control and driver power electronics compared to permanent magnet brushless DC motors.

In the art, there exists a widely accepted notion that brushless DC motors are advantageous when compared to brushed motors because of the lack of friction present between parts. While this notion may be true for low-torque high rpm brushed motors wherein lost energy due to brush friction and windage may add up to a significant portion of the total energy consumed and in turn reduce the efficiency thereof while leading to mechanical wear of brushes and commutators, for high-torque low rpm motors, this loss and wear can become comparably negligible. As a corollary, with a novel planar commutator and a novel freewheel use case, as set forth by the present disclosure, relatively costly complex electronics and microcontroller/software needed for electronic commutation and loss of kinetic energy of the bicycle in cases of diminishing marginal utility of regenerative braking or non-power assisting mode, are both avoided.

Brief Description of the Figures of the Present Invention

Accompanying drawings are given solely for the purpose of exemplifying a planar commutator on the rotor and an inverse freewheel on the shaft of the rotor of an electric bicycle motor, whose advantages over prior art were outlined above and will be explained in brief hereinafter.

The drawings are not meant to delimit the scope of protection as identified in the claims nor should they be referred to alone in an effort to interpret the scope identified in said claims without recourse to the technical disclosure in the description of the present invention.

Figure 1 demonstrates a radial flux DC motor with four three-pole rotors arranged in multiple parallel planes according to an embodiment of the present disclosure.

Figure 2 demonstrates the planar commutator with inverse freewheel embodiment as described in the present disclosure.

Figure 3 demonstrates a planar commutator and an exploded view of the planar commutator as described in the present disclosure. Figure 4 demonstrates an axial flux DC motor with three-pole rotors grouped into a single plane by the planar commutator according to an embodiment of the present disclosure.

Figure 5 demonstrates an inverse freewheel mechanism and the exploded view of the inverse freewheel mechanism integrated to the planar commutator via the rotor according to an embodiment of the present disclosure.

Detailed Description of the Present Invention

100 Multi-parallel three-pole radial flux DC motor

110 Multi-plane three-pole rotors

120 Radial flux DC motor shaft

130 Radial magnetic flux

140 Three segment commutator

150 Carbon brushes

200 Planar commutator

210 Outer ring conductor piece

211 Outer ring commutator segments

212 Outer ring lead

220 Mid ring conductor piece

221 Mid ring commutator segments

222 Mid ring lead

230 Inner ring conductor piece

231 Inner ring commutator segments

232 Inner ring lead

240 Insulating base 300 Muti parallel three-pole axial flux rotor

310 Coil/pole leads

320 Carbon brushes

330 Stator/field magnet pairs

340 Coil/poles

350 Multi parallel pole connection

400 Inverse freewheel

410 Nut

420 Freewheel

430 Central hub piece

440 Shaft collar

450 Shaft

An important feature of a motor for use in specific applications such as in electric bicycles is that it should be able to self-start. In order to achieve this, at any instant while any coil is inactive during switching of poles, other coils/poles should continue to provide sufficient level of torque. As such, a quite important feature in electric bicycle motors is rendered effective, such that said motor can always self-start rotation from standstill when the coils/poles are energized. On the other hand, referring specifically to a pre-transformed embodiment of the presently disclosed invention with reference to Figure 1, the brushed DC motor topology comprising multi-paralleled radial flux three- pole rotors (110) rotating in different planes on the same shaft (120) is demonstrated, together making up a multi-parallel three-pole radial flux DC motor (100). The torque of rotation that can be obtained using three-poles may be limited or even truncated depending on the requirements of the application under different embodiments. The torque exerted by the motor (100) on the shaft (120) can be increased in multiples of three-pole rotors connected in parallel. According to at least one embodiment as demonstrated in Figure 1, four three-pole rotors (110) may be multi-paralleled.

The planar commutator (200) integrated into a disc rotor (300) having an inverse freewheel (400) as shown with respect to Figure 2 and according to the present disclosure, can transform rotors (110) of said motor (100) into said disc rotor (300) as disclosed below and comprises four members as further shown with reference to Figure 3. Said four members comprise three ring conductor pieces (210, 220, 230) and one electrically insulating support member (240) said three ring conductor pieces (210, 220, 230) are affixed thereon. In conjunction with said parts, in contact with the segments of the ring conductors (211, 221, 231) there also are comprised carbon brush pairs (320) whose quantity or contact area can be adjusted based on the amount of current capacity needed for the specific use case. Said three ring conductor pieces (210, 220, 230) are arranged coaxially, such that while one of said three ring conductor pieces (220) is in the middle, another ring conductor piece is in the outer (210) and one in the inner (230) section of the complete assembly. Said middle ring conductor (220) is arranged such that a base ring thereof is displaced in a different, but still in a parallel plane, thereby enabling all aligned commutator segments (211, 221, 231) of the three ring conductors to operate together.

The planar commutator (200) as set forth according to the present disclosure has the advantage of addressing a common problem in configurations with many parallel three-pole rotor radial flux DC motors (100) an embodiment of which has been shown with respect to Figure 1. As the number of paralleled rotors increase, the length of the shaft also needs to increase, rendering a motor that progressively and orthogonally protrudes out of the plane of the bicycle and deviating from a preferred form factor. Consequently, magnets tasked with generating the radial field flux (130) are both required to be larger, bulkier and also more expensive. It is of paramount importance for motors to be used for electric bicycles to have the advantage of a form fitting, compact size. Present invention addresses this problem while retaining the advantage of multi parallel three-pole motors.

As mentioned, the planar commutator (200) as shown with respect to Figure 4, whilst transposing the overall motor (100) into a form fitting topology (300), also maintains the self-starting feature that is essential to the operation specifically in the case of electric bicycles. Furthermore, coils/poles (340) are grouped and co-planarly positioned as opposed to positioning on different planes, diminishing the size and distributing the magnets (330) thus converting the radial magnetic flux into axial flux, correspondingly, allowing the motor topology to display characteristics of a shorter shaft, a disk-like motor with a smaller than typical width and a larger-than-typical diameter, as opposed to a long, cylindrical motor that is fundamentally unsuitable for application in electric bicycles as a form factor.

According to the teaching of the present disclosure, what follows is that since typical allowable speed limit for electric power assisted cycles in many jurisdictions is around 25 kph and torque takes precedence over high speed, it is particularly advantageous to generate more torque with a motor with greater radius, hence one that utilizes the axial flux topology.

Disclosed invention transposes electrically paralleled quantity N three-pole radial flux rotors fixed on a common shaft and positioned in different parallel planes into a 3 times N pole axial flux disc rotor, all poles thereof rotating on a single plane as demonstrated with respect to Figure 4. In the meantime, a single large area magnetic field (130) is broken down and distributed into smaller area fields and therefore resulting smaller magnet pairs (330).

It can therefore be summarized that the planar commutator (200) of Figure 3 and disclosed according to the present disclosure has the advantage of having fewer parts, facilitating easy assembly using shrink fitting of the conducting rings (210, 220, 230) into the insulating base (240). Furthermore, with this design, conducting parts (210, 220, 230) of the commutator (200) can be manufactured in a simple manner yet, based on their geometry allowing them to be obtained from sheet metal as opposed to bent and/or irregular geometries. As a result of the planar contact surfaces, capacity of current flow between brush and conductor commutator segments (211, 221, 231) is drastically improved compared to that of relatively small radius shaft mounted, conventional commutators. Losses in power commutation to rotor are also greatly reduced with the aid of carbon brushes (320) with high metal content and lower count of power MOSFETs in the driver circuit when compared to ones accomplishing the same with microcontroller based three phase, Hall sensor or other positioning method dependent H-bridges with six MOSFETs. Furthermore, a pair of bulky magnets are reduced into much smaller sized magnets.

According to at least one embodiment as shown in Figure 4, the planar commutator (200) in the present invention is configured such that the gaps between commutator segments (211, 221, 231) of said commutator (200) are arranged to line up with mid of coils/poles (340).

Another feature of the planar commutator according to the embodiment shown in Figure 4 is that said carbon brushes (320) are configured to be arranged on segments (211, 221, 231) in a manner such that there exists an angle corresponding to a one-half segment between said brush pairs (320) referenced to the rotor (300) center.

According to the embodiment as demonstrated in Figure 4, the base of the mid ring conductor base (220) of the commutator is situated on another plane relative to the other ring conductors (210, 230).

According to at least one embodiment of the disclosed invention, the number of stator/field magnet pairs (330) providing axial magnetic flux are configured such that they amount to two thirds (2/3) of the number of rotor poles (340). Additionally, each rotor pole (340) face must be configured such that they span over two thirds (2/3) of a corresponding stator magnet pair (330) surface. According to various other embodiments, rotor pole (340) faces and stator magnet (330) surfaces are configured such that they ideally span over a full 360-degree turn.

Above recited features are set forth as the optimum conditions for the intended operation of the multi-parallel three-pole axial flux rotor (300) as disclosed according to various embodiments. It can be appreciated readily by the person skilled in the art that, based on different considerations, some of the conditions could be altered and modified, for different possible advantages, albeit to the detriment of the overall performance of the motor.

For electric bicycles, the power generated by the motor needs to be delivered to at least one wheel. For this purpose, generally, a transmission method suitable for the type of motor is used. In mid-motor configurations, power is directly integrated to the crankset, subsequently delivered to the wheel via the chain. In hub motor configurations, motor is centrally situated in either one of the wheels, directly delivering power to said wheel. Both types of motors can start operating as electrical generators the moment drive power ceases to be supplied, therefore generating electrical power in place of mechanical power to drive the wheels.

Through regenerative braking, that is, through the electricity produced in the generator state of the motor, it is possible to re/charge the battery. This however directly comes at the expense of kinetic and potential energy of the bicycle, which can eventually bring said bicycle to a complete stop if elaborate sensors and electronics are not provided. To eliminate this effect, whilst the bicycle is in motion whereas the motor is not generating any assisting power, there should be a mechanism to decouple the motor from the wheel, or stop the current flow in the motor electrically.

According to the present disclosure, a freewheel mechanism (400) as shown with respect to Figure 2, suitable for use in electric bicycles is proposed. Disclosed invention, enables, in one direction, delivery of power generated by the motor to the wheel, and in the other direction, ensures total mechanical separation preventing switching of the motor to generator mode and consumption of kinetic or potential energy of the bicycle without any elaborate sensor and electronics.

Freewheel or overrunning clutch, as is known in the art, is a wheel allowed to normally rotate in one direction but ratchets in the reverse direction. A standard application for bicycles, whether electric or otherwise, is that it is fixedly connected to the right side of the rear wheel shaft of the bicycle with chain rolled therearound, in which configuration it can sometimes be called a freehub. This arrangement enables the power coming from the crankset to be delivered to the rear wheel. At a certain speed, where the cyclist ceases pedaling, the connection established between the wheel and the crankset is disrupted, therefore preventing the revolving rear wheel from exerting any force on the crankset.

According to at least one embodiment of the present disclosure as demonstrated with respect to Figure 5, it is also set forth a freewheel (420) mechanism that is configured such that a freewheel is connected to the motor (300) shaft (450), instead of the right side of the rear wheel shaft. This freewheel (420) connects to the motor shaft (450) in the inverse (sides flipped) setup of having been connected to the rear wheel shaft as found in the examples in the art. This inverse setup is devised to ensure a one-way power delivery relationship is formed between the motor (300) and the rear wheel, i.e. the power generated by the motor can be delivered to the rear wheel. In the cycling process, whenever the motor (300) ceases to supply power, freewheel (420) is configured to be engaged such that the momentum of the bicycle is preserved, facilitating a normal cycling or cruising without pedaling of the bicycle and without the active assist of the motor (300). This inverse freewheel setup enables delivery of power to the rear wheel through a sprocket that uses the standard disk brake rotor coupling interface on the left side of the rear wheel shaft rendering a torque convertible power transfer independent from the original gear set of the bicycle.

According to another embodiment as shown with respect to Figure 5, proposed freewheel (420) has disposed therein a central hub piece (430). Said freewheel (420) is screwed on said central hub piece (430), which is in turn screwed on the motor shaft (450) all of which are threaded such that they self-lock as power is sourced from the motor (300). These members, according to an embodiment, while power is being transmitted, are also provided with a nut (410) and a shaft collar (440) situated in the front and post-freewheel respectively, both axially fixed to the motor shaft (450) having a high bending stiffness such that the alignment with the rear wheel gear is always maintained under torque.

According to an embodiment of the present invention, an electric bicycle apparatus for an electric bicycle, simplifying commutation with reduced partcount, said electric bicycle apparatus being suitable for use with permanent magnet brushed axial flux DC motors having a configuration comprising a rotor (300) coil/pole leads (310), carbon brushes (320), multiple stator/field magnet pairs (330) and a multiplicity of coils/poles (340), said apparatus comprising a planar commutator (200) with concentric conductor pieces (210, 220, 230), and an insulating base (240) is proposed.

According to at least an embodiment of the present invention, said plurality of concentric conductor pieces (210, 220, 230) are in the form of flat rings with unequal diameters.

According to at least an embodiment of the present invention, two of said plurality of concentric conductor pieces (210, 220, 230) namely an inner conductor piece (230) and an outer conductor piece (210) are concentrically arranged in a coplanar manner.

According to at least an embodiment of the present invention, said insulating base (240) and said concentric conductor pieces (210, 220, 230) are arranged to form a circular locus of conducting segments on which a plurality of carbon brushes (320) can be configured to be in contact.

According to at least an embodiment of the present invention, a mid ring conducting piece (220) that is in the form of a flat ring is disposed such that the base of which is positioned in a different plane to the inner and outer coplanar conducting pieces (210, 230).

According to at least an embodiment of the present invention, said plurality of conducting pieces (210, 220, 230) are electrically isolated from each other.

According to at least an embodiment of the present invention, said plurality of concentric conductor pieces (210, 220, 230) each comprise multiple ring leads (212, 222, 232) on which rotor coils/poles (340) can be contacted by their respective leads (310) in a predetermined systematic pattern.

According to at least an embodiment of the present invention, said apparatus further comprises a freewheel (420) inversely attachable to a central hub piece (430) structurally associated with a DC motor shaft (450) and arranged to mechanically decouple a rear wheel of a bicycle from the motor when said motor is in non-power assisting mode.

According to at least an embodiment of the present invention, said insulating base (240) comprises slots in which said mid ring conductor piece (220), said outer ring conductor piece (210) and inner ring conductor piece (230) can be tightly snapped thereinto.

According to at least an embodiment of the present invention, said plurality of concentric conductor pieces (210, 220, 230) each respectively comprise four commutator segments (211, 221, 231) arranged thereon in a circular locus in an equidistant manner.

According to at least an embodiment of the present invention, said multiple coil/pole contacting ring leads (212, 222, 232) are positioned on said commutator segments (211, 221, 231). According to at least an embodiment of the present invention, said ring conductor pieces (210, 220 230) are positioned such that said plurality of carbon brushes (320) carrying a high side and a ground side potential of a supply voltage lie at an angle corresponding to the span of one and a half conducting segment (211, 221, 231) with respect to the center of the planar commutator (200).

According to at least an embodiment of the present invention, said pairs of said carbon brushes (320) are in electrical contact with the segments (211, 221, 231) of the ring conductor pieces (210, 220, 230).

According to at least an embodiment of the present invention, said planar commutator (200) is positioned in relation to said DC motor such that gaps between commutator segments (211, 221, 231) are arranged to align with the center of said multiple coils/ poles (340).

According to at least an embodiment of the present invention, said planar commutator (200) comprises an assembly obtainable by shrink fitting of the conducting rings (210, 220, 230) into the insulating base (240).

According to at least an embodiment of the present invention, current flow between carbon brushes (320) and conducting commutator segments (211, 221, 231) is adapted to be higher through planar contact surfaces relative to arc-wise bent segments mounted on a shaft with relatively smaller radius.

According to an embodiment of the present invention, a freewheel apparatus suitable for an electric bicycle comprising at least a rear wheel and a DC motor is proposed. According to at least an embodiment of the present invention, said apparatus comprises an inverse freewheel (400).

According to at least an embodiment of the present invention, said inverse freewheel (400) having a freewheel (420) configured to be inversely attachable to a central hub piece (430) structurally associated with a motor shaft (450) of said DC motor.

According to at least an embodiment of the present invention, said inverse freewheel (400) is configured such that it mechanically decouples a rear wheel from said DC motor when said DC motor is in non-power assisting mode.

According to at least an embodiment of the present invention, said inverse freewheel (400) comprises a stopping mechanism further comprising a nut (410), a central hub piece (430) and a shaft collar (440) such that said freewheel (420) retains its sense and axial position on a shaft (450) while under drive.

According to at least an embodiment of the present invention, said inverse freewheel (400) enables delivery of power to said rear wheel through a sprocket with a specific number of teeth in relation to a freewheel (420) teeth count, configured to be usable with a standard disk brake rotor coupling interface on the left side of a rear wheel shaft, whereby a torque convertible power transfer independent from an original gear set of a bicycle is enabled.

According to an embodiment of the present invention, an electric bicycle comprising a rear wheel with a disc brake rotor standard coupling interface, an inverse freewheel (400) that transmits power to the said rear wheel via a sprocket compatible with said disc brake rotor standard coupling interface, at least one brushed DC motor comprising a commutation device is proposed.

According to at least an embodiment of the present invention, said freewheel (420) is an inverse freewheel (400) that is structurally associated with said DC motor shaft (450).

According to at least an embodiment of the present invention, said inverse freewheel (400) is screwed on a central hub piece (430).

According to at least an embodiment of the present invention, said inverse freewheel (400) is configured such that, as said brushed DC motor is in nonpower assist mode, said rear wheel is decoupled from said motor.

According to at least an embodiment of the present invention, commutation device is a planar commutator (200) comprises three conducting members (210, 220, 230) in the form of flat rings with unequal diameters, two of which are concentrically arranged in a coplanar manner (210, 230) and the middle conducting member (220) being disposed such that the base thereof is positioned in a different plane to the coplanar, concentrically-arranged conducting members (210, 230) and, said conducting members (210, 220, 230) further comprising multiple ring leads (212, 222, 232) on which coils/poles (340) can be contacted by their leads (310) in a systematic pattern.

According to at least an embodiment of the present invention, the number of stator/field magnet pairs (330) found in said DC motor providing axial magnetic flux are arranged to be two thirds of the quantity of rotor poles.

Claims

1) An electric bicycle apparatus for an electric bicycle, simplifying commutation with reduced part-count, said electric bicycle apparatus being suitable for use with permanent magnet brushed axial flux DC motors having a configuration comprising a rotor (300) coil/pole leads (310), carbon brushes (320), multiple stator/field magnet pairs (330) and a multiplicity of coils/poles (340), said apparatus comprising a planar commutator (200) with concentric conductor pieces (210, 220, 230), and an insulating base (240) characterized in that, said plurality of concentric conductor pieces (210, 220, 230) are in the form of flat rings with unequal diameters, two of said plurality of concentric conductor pieces (210, 220, 230) namely an inner conductor piece (230) and an outer conductor piece (210) are concentrically arranged in a coplanar manner, said insulating base (240) and said concentric conductor pieces (210, 220, 230) are arranged to form a circular locus of conducting segments on which a plurality of carbon brushes (320) can be configured to be in contact.

2) An electric bicycle apparatus for an electric bicycle as in Claim 1, characterized in that a mid ring conducting piece (220) that is in the form of a flat ring is disposed such that the base of which is positioned in a different plane to the inner and outer coplanar conducting pieces (210, 230).

3) An electric bicycle apparatus for an electric bicycle as in Claims 1 and 2, characterized in that said plurality of conducting pieces (210, 220, 230) are electrically isolated from each other. 4) An electric bicycle apparatus for an electric bicycle as in Claims 1 to 3 characterized in that said plurality of concentric conductor pieces (210, 220, 230) each comprise multiple ring leads (212, 222, 232) on which rotor coils/poles (340) can be contacted by their respective leads (310) in a predetermined systematic pattern.

5) An electric bicycle apparatus for an electric bicycle as in Claims 1 to 4 characterized in that said apparatus further comprises a freewheel (420) inversely attachable to a central hub piece (430) structurally associated with a DC motor shaft (450) and arranged to mechanically decouple a rear wheel of a bicycle from the motor when said motor is in non-power assisting mode.

6) An electric bicycle apparatus for an electric bicycle as in any preceding Claim, characterized in that said insulating base (240) comprises slots in which said mid ring conductor piece (220), said outer ring conductor piece (210) and inner ring conductor piece (230) can be tightly snapped thereinto.

7) An electric bicycle apparatus for and electric bicycle as in any preceding Claim characterized in that said plurality of concentric conductor pieces (210, 220, 230) each respectively comprise four commutator segments (211, 221, 231) arranged thereon in a circular locus in an equidistant manner.

8) An electric bicycle apparatus for and electric bicycle as in any preceding Claim characterized in that said multiple coil/pole contacting ring leads (212, 222, 232) are positioned on said commutator segments (211, 221, 10) An electric bicycle apparatus for an electric bicycle as in any preceding Claim, characterized in that said ring conductor pieces (210, 220

230) are positioned such that said plurality of carbon brushes (320) carrying a high side and a ground side potential of a supply voltage lie at an angle corresponding to the span of one and a half conducting segment (211, 221,

231) with respect to the center of the planar commutator (200).

11) An electric bicycle apparatus for an electric bicycle as in any preceding Claim, characterized in that said pairs of said carbon brushes (320) are in electrical contact with the segments (211, 221, 231) of the ring conductor pieces (210, 220, 230).

12) An electric bicycle apparatus for an electric bicycle as in any preceding Claim, characterized in that said planar commutator (200) is positioned in relation to said DC motor such that gaps between commutator segments (211, 221, 231) are arranged to align with the center of said multiple coils/ poles (340).

13) An electric bicycle apparatus for an electric bicycle as in any preceding Claim, characterized in that said planar commutator (200) comprises an assembly obtainable by shrink fitting of the conducting rings (210, 220, 230) into the insulating base (240).

14) An electric bicycle apparatus for an electric bicycle as in any preceding Claim, characterized in that current flow between carbon brushes (320) and conducting commutator segments (211, 221, 231) is adapted to be higher through planar contact surfaces relative to arc-wise bent segments mounted on a shaft with relatively smaller radius. 15) A freewheel apparatus suitable for an electric bicycle comprising at least a rear wheel and a DC motor, characterized in that said apparatus comprises an inverse freewheel (400), said inverse freewheel (400) having a freewheel (420) configured to be inversely attachable to a central hub piece (430) structurally associated with a motor shaft (450) of said DC motor, said inverse freewheel (400) is configured such that it mechanically decouples a rear wheel from said DC motor when said DC motor is in nonpower assisting mode.

16) A freewheel apparatus as in Claim 15, characterized in that said inverse freewheel (400) comprises a stopping mechanism further comprising a nut (410), a central hub piece (430) and a shaft collar (440) such that said freewheel (420) retains its sense and axial position on a shaft (450) while under drive.

17) A freewheel apparatus as in Claims 15 and 16, characterized in that said inverse freewheel (400) enables delivery of power to said rear wheel through a sprocket with a specific number of teeth in relation to a freewheel (420) teeth count, configured to be usable with a standard disk brake rotor coupling interface on the left side of a rear wheel shaft, whereby a torque convertible power transfer independent from an original gear set of a bicycle is enabled.

18) An electric bicycle comprising apparatuses according to Claim 1 and 15. 19) An electric bicycle comprising a rear wheel with a disc brake rotor standard coupling interface, an inverse freewheel (400) that transmits power to the said rear wheel via a sprocket compatible with said disc brake rotor standard coupling interface, at least one brushed DC motor comprising a commutation device characterized in that; said freewheel (420) is an inverse freewheel (400) that is structurally associated with said DC motor shaft (450) said inverse freewheel (400) is screwed on a central hub piece (430), said inverse freewheel (400) is configured such that, as said brushed DC motor is in non-power assist mode, said rear wheel is decoupled from said motor.

20) An electric bicycle as in Claim 19, characterized in that said commutation device is a planar commutator (200) comprises three conducting members (210, 220, 230) in the form of flat rings with unequal diameters, two of which are concentrically arranged in a coplanar manner (210, 230) and the middle conducting member (220) being disposed such that the base thereof is positioned in a different plane to the coplanar, concentrically-arranged conducting members (210, 230) and, said conducting members (210, 220, 230) further comprising multiple ring leads (212, 222, 232) on which coils/poles (340) can be contacted by their leads (310) in a systematic pattern.

21) An electric bicycle as in Claims 19 and 20, characterized in that, the number of stator/field magnet pairs (330) found in said DC motor providing axial magnetic flux are arranged to be two thirds of the quantity of rotor poles. 22) A commutation device, simplifying commutation with reduced part-count, suitable for use with axial flux DC motors at least comprising a planar commutator (200) with concentric conductor pieces (210, 220, 230), and an insulating base (240) characterized in that, said plurality of concentric conductor pieces (210, 220, 230) are in the form of flat rings with unequal diameters, two of said plurality of concentric conductor pieces (210, 220, 230) namely an inner conductor piece (230) and an outer conductor piece (210) are concentrically arranged in a coplanar manner, said insulating base (240) and said concentric conductor pieces

(210, 220, 230) are arranged to form a circular locus of conducting segments on which a plurality of carbon brushes (320) can be configured to be in contact; and said device further comprises a mid ring conducting piece (220) in the form of a flat ring, disposed such that the base of which is positioned in a different plane to the inner and outer coplanar conducting pieces (210, 230).