A statorless axial flux wheel-hub generator for an electric vehicle

Abstract

The application discloses a statorless axial flux wheel hub generator for an electric vehicle, which comprises a gear speed increaser, a coil array disc and two magnet array discs, the two magnet array discs are arranged in parallel and oppositely, and the two magnet array discs are fixedly connected on the two sides of a vehicle wheel hub through wheel hub side covers respectively; the coil array disc is arranged between the two magnet array discs; the gear speed increaser comprises a driving wheel and a driven wheel which are engaged with each other, the driving wheel is connected with the vehicle wheel hub, and the driven wheel is connected with the coil array disc; when the vehicle wheel hub rotates to drive the driving wheel to rotate, the driven wheel drives the coil array disc to rotate relative to the two magnet array discs. The design is compact in structure, small in starting torque, high in self-power generation efficiency, and can efficiently recover the kinetic energy of the vehicle.

Description

Technical Field

[0001] This invention relates to the field of generator technology, specifically to a statorless axial flux generator that generates electricity by utilizing the rotation of vehicle wheel hubs. Background Technology

[0002] Traditional axial flux permanent magnet generators typically include a stator core. For example, the invention patent CN115589093A discloses a two-stage frequency-variable axial flux permanent magnet generator, which includes a stator and a rotor with axial clearance. The stator includes a stator core, which includes several core blocks arranged circumferentially. The core blocks are wound with a first set of windings and a second set of windings with different pole numbers. The first set of windings and the second set of windings each include several coils arranged circumferentially. The circumferential surface of the first set of windings is different from that of the second set of windings. The rotor includes a shaft, a rotor core, a first set of magnetic poles, and a second set of magnetic poles. The rotor core is disc-shaped and fixed to the shaft. The first set of magnetic poles and the second set of magnetic poles rotate synchronously with the rotor core. The circumferential surface of the first set of magnetic poles is different from that of the second set of magnetic poles. The first set of magnetic poles has the same number of poles as the first set of windings, and the second set of magnetic poles has the same number of poles as the second set of windings.

[0003] However, in the operation of such generators with stator cores, the rotation of the generator's magnetic field generates eddy currents in the stator core, leading to hysteresis and eddy current losses, as well as reluctance torque. This causes difficulties in starting and low-speed operation, especially at low speeds where power generation and efficiency are low. In the field of electric vehicles, particularly two-wheeled electric vehicles, achieving efficient power generation and energy recovery is crucial for extending driving range. Existing technologies have attempted to integrate motors into wheel hubs, but most structures remain complex or fail to effectively address the issues of iron losses and reluctance torque. Furthermore, the traditional single-rotor, single-stator structure has limited relative tangential speed between the magnet disk and the coil disk, leaving room for improvement in power generation efficiency. While dual-rotor or dual-stator structures exist, they often require complex support and transmission mechanisms, making integration within the limited space of a wheel hub impractical. Therefore, there is an urgent need for a generator solution that is compact, has low starting resistance, high power generation efficiency, and is particularly suitable for integration into the wheel hub of electric vehicles for autonomous power generation and energy recovery. Summary of the Invention

[0004] To address the problems mentioned in the background, this solution provides a statorless axial flux hub generator for electric vehicles, which has a compact structure, low starting torque, high self-generation efficiency, and can efficiently recover vehicle kinetic energy.

[0005] The technical solution adopted by this invention to solve its technical problem is as follows: a statorless axial flux hub generator for electric vehicles, comprising a gear speed increaser, a coil array disk, and two magnet array disks. The two magnet array disks are arranged in parallel and opposite directions, and are respectively fixedly connected to both sides of the vehicle wheel hub by a hub side cover. The coil array disk is disposed between the two magnet array disks. The gear speed increaser is disposed inside the vehicle wheel hub and includes a driving wheel and a driven wheel that mesh with each other. The driving wheel is connected to the vehicle wheel hub, and the driven wheel is connected to the coil array disk. When the vehicle wheel hub rotates, driving the driving wheel to rotate, after a series of transmission speed-ups (the transmission ratio between the driving wheel and the driven wheel) by the gear speed increaser, the driven wheel drives the coil array disk to rotate relative to the two magnet array disks, thereby cutting magnetic field lines to generate electricity.

[0006] Furthermore, the coil array disk includes a coreless coil frame on which a plurality of coil windings are embedded.

[0007] Furthermore, the coil frame is provided with a coil connection flange for connecting the driven wheel at the center, and the coil frame is also provided with a plurality of radially distributed heat dissipation holes, with the coil windings embedded between the heat dissipation holes.

[0008] Furthermore, the coil frame is made of non-magnetic materials such as resin or plastic, resulting in either a cavity assembly structure or an integral potting molding. The manufacturing method of the coil array disk is as follows: First, the coil windings are evenly and flatly arranged on a platen in a potting mold. Then, thermally conductive resin material is poured into the mold to completely encapsulate the coil windings, ensuring that the coil winding terminals / leads are exposed for easy wiring. After baking and curing at a certain temperature, the coil array disk is demolded and then mounted on a circuit board to form the final coil array disk. Alternatively, the coil array disk can also be manufactured using PCB (printed circuit board) technology, embedding the coil windings within the PCB board to achieve higher precision and more complex winding layouts, further reducing size and losses.

[0009] Furthermore, both of the aforementioned magnet array disks include a magnet frame, on which a plurality of N-pole magnets and S-pole magnets are evenly distributed in a circumferential array. The N-pole magnets and S-pole magnets are arranged alternately along the circumferential direction, and the N-pole magnets and S-pole magnets on the two magnet array disks are paired and arranged opposite each other. The magnet array disks may also employ a Halbach array permanent magnet structure to improve the air gap magnetic flux density and reduce magnetic leakage.

[0010] Furthermore, it also includes a motor spindle and a conductive slip ring. The motor spindle is fixed to the vehicle frame, and the conductive slip ring is mounted on the motor spindle and electrically connected to the coil array disk.

[0011] Furthermore, it also includes wires, and the motor spindle is provided with wire lead holes. One end of the wire passes through the wire lead holes and connects to the conductive slip ring to lead out the electrical energy generated by the coil array disk.

[0012] Furthermore, this design can be applied to power generation in various applications, including but not limited to two-wheeled electric bicycles, electric motorcycles, drones, military and police vehicles, yacht power generation, and emergency situations.

[0013] The beneficial effects of this invention are: 1. Coreless design: The coil array adopts a coreless design, which fundamentally eliminates the hysteresis loss and eddy current loss caused by the stator core, reduces the generator's weight, and eliminates cogging torque, making starting easier and particularly beneficial for generating electricity using low-speed kinetic energy.

[0014] 2. High-efficiency power generation by reverse rotation: Through the ingenious design of the gear speed increaser, the unidirectional rotation input of the vehicle wheel hub is converted into the same-direction or opposite-direction rotation between the magnet array and the coil array, which greatly improves the relative tangential speed between the two, thereby significantly improving the power generation efficiency at the same wheel hub speed.

[0015] 3. Compact structure: The structure of the dual magnet array clamping coil array and the integrated design of the gear speed increaser make the entire generator short in axial dimension, compact in structure and high in power density, which is very suitable for installation in space-constrained wheel hubs.

[0016] 4. High-efficiency energy recovery: This generator can directly utilize the rotation of the wheels to achieve efficient recovery of the kinetic energy of electric vehicles, converting it into electrical energy to directly drive the electric vehicle's drive motor or charge the battery, effectively achieving ultra-long range. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the gear speed increaser of the present invention; Figure 3 This is a schematic diagram of the coil array disk and magnet array disk of the present invention. Detailed Implementation

[0018] The present invention will be further described below with reference to embodiments. It is worth noting that these specific embodiments are merely representative embodiments of the present invention, and the specific methods, apparatuses, conditions, materials, etc., exemplified are not intended to limit the present invention or the corresponding specific embodiments.

[0019] A statorless axial flux hub generator for electric vehicles, such as Figures 1-3 As shown, the device includes a gear speed increaser 7, a coil array disk 4, and two magnet array disks 1. The two magnet array disks 1 are arranged in parallel opposite directions and are respectively fixedly connected to both sides of the vehicle wheel hub 3 through a hub side cover 2, and can rotate together with the vehicle wheel hub 3. The coil array disk 4 is disposed between the two magnet array disks 1. The gear speed increaser 7 is disposed inside the vehicle wheel hub 3. The gear speed increaser 7 includes a driving wheel 8 and a driven wheel 9 that mesh with each other. The driving wheel 8 adopts a sun gear structure, and the driven wheel 9 adopts an internal gear ring structure. The driving wheel 8 is connected to the driven wheel 9 through four planetary gears distributed in a cross shape. The driving wheel 8 is connected to the vehicle wheel hub 3, and the driven wheel 9 is connected to the coil array disk 4.

[0020] Furthermore, the coil array disk 4 includes a coreless coil frame, on which several coil windings are embedded. The coil frame has a coil connection flange at its center for connecting to the driven wheel, and also has multiple radially distributed heat dissipation holes, with the coil windings embedded between the heat dissipation holes.

[0021] Furthermore, the coil frame is made of non-magnetic materials such as resin or plastic, which can result in either a cavity assembly structure or an integral potting molding.

[0022] Furthermore, the manufacturing method of the coil array disk 4 is as follows: First, the coil winding is evenly and flatly arranged in a potting mold. Then, thermally conductive resin material is poured into the mold to completely encapsulate the coil winding. During potting, care is taken to leave the wire ends / leads of the coil winding exposed for easy wiring. After baking and curing at a certain temperature, the circuit board is installed after demolding to form the final coil array disk 4.

[0023] Furthermore, the coil array disk 4 can also be manufactured using PCB (printed circuit board) technology, embedding the coil windings within the PCB board to achieve higher precision and more complex winding layouts, thereby further reducing volume and losses.

[0024] Furthermore, both of the aforementioned magnet array disks 1 include an annular magnet frame. The magnet frame has mounting countersunk holes for connecting the hub cover 2. One side of the magnet frame has several radially arranged fan-shaped grooves, which are evenly distributed in a circumferential array on the disk surface of the magnet frame. Several N-pole magnets and S-pole magnets are installed in the fan-shaped grooves, which are arranged alternately along the circumference. The N-pole magnets and S-pole magnets on the two magnet array disks 1 are paired and arranged opposite each other (i.e., the N-pole magnet on one magnet array disk 1 faces the S-pole magnet on the other magnet array disk 1). The magnet frame is made of Q235 iron, with a thickness of 5-12 mm, an outer diameter of 150-300 mm, and a central hole diameter of 50-100 μm. The magnet frame has several lugs evenly distributed around its outer ring, and each lug has a countersunk hole for mounting, facilitating heat dissipation from the magnet frame to the outer periphery of the stepped plate. The fan-shaped groove features a chamfered step to facilitate the magnet's installation and embedding. The groove depth and chamfered step are optimized to guide the magnetic field lines inward, preventing magnetic leakage from the back side. The N-pole and S-pole magnets are made of permanent magnet materials (such as neodymium iron boron).

[0025] Furthermore, the magnet array disk 1 can also adopt a Halbach array permanent magnet structure to improve the air gap magnetic flux density and reduce magnetic leakage.

[0026] Furthermore, it also includes a motor spindle 6 and a conductive slip ring 10. The motor spindle 6 is fixed on the vehicle frame, and the conductive slip ring 10 is mounted on the motor spindle 6 and electrically connected to the coil array disk 4.

[0027] Furthermore, it also includes a wire 11. The motor spindle 6 is provided with a wire lead hole. One end of the wire 11 passes through the wire lead hole and connects to the conductive slip ring 10 to draw out the electrical energy generated by the coil array disk 4.

[0028] Furthermore, the generator of this embodiment can be used to generate electricity in various situations, including but not limited to two-wheeled electric bicycles, electric motorcycles, drones, military and police vehicles, yachts, or in emergencies.

[0029] The working principle of this embodiment is as follows: the coil array disks 4 on both sides of the vehicle wheel hub 3 are parallel and opposite each other. The coil array disks 4 are precisely set in the axial gap between the two magnet array disks 1. The axial gap between the coil array disks 4 and the two magnet array disks 1 can be adjusted according to production requirements. When the vehicle is moving and the vehicle wheel hub 3 rotates, it drives the two magnet array disks 1 connected to it to rotate synchronously (assuming forward rotation); at the same time, the rotation of the wheel hub side cover 2 drives the drive wheel 8 of the gear speed increaser 7 to rotate forward. After a series of transmissions by the gear speed increaser 7, the driven wheel 9 is driven to rotate in the opposite direction (reverse rotation). The reverse rotation of the driven wheel 9 in turn drives the coil array disk 4 fixed to it to rotate in the opposite direction. Thus, the coil array disk 4 rotates in the opposite direction relative to the two magnet array disks 1. A high-speed relative reverse motion is formed between the magnet array (forward rotation) and the coil array (reverse rotation), which greatly enhances the effect of cutting magnetic lines of force and generates a high induced AC electromotive force in the coil winding 12 of the coil array disk 4. The generated electrical energy is conducted through the lead wire to the conductive slip ring 10 installed on the motor main shaft 6, and finally output through the wire 11 led out from the oblique hole in the center of the main shaft. After rectification and voltage regulation, it directly supplies power to the vehicle drive wheels or charges the battery.

[0030] The above description is merely a preferred embodiment of the present invention and should not be construed as limiting the scope of the present invention. Any simple equivalent changes and modifications made in accordance with the scope of the patent application and the description of the invention shall still fall within the scope of the patent of the present invention.

Claims

1. A statorless axial flux hub generator for electric vehicles, characterized in that, The device includes a gear speed increaser, a coil array disk, and two magnet array disks. The two magnet array disks are arranged in parallel and opposite directions, and are respectively fixedly connected to both sides of the vehicle wheel hub by a hub cover. The coil array disk is disposed between the two magnet array disks. The coil array disk includes a coil frame with several coil windings embedded on it. The coil frame is integrally potted using a non-magnetic material. The gear speed increaser includes a driving wheel and a driven wheel that mesh with each other. The driving wheel is connected to the vehicle wheel hub, and the driven wheel is connected to the coil array disk. When the vehicle wheel hub rotates, causing the driving wheel to rotate, the driven wheel causes the coil array disk to rotate relative to the two magnet array disks.

2. A statorless axial flux hub generator for electric vehicles according to claim 1, characterized in that, The coil frame has a coil connection flange at its center for connecting the driven wheel. The coil frame also has a plurality of radially distributed heat dissipation holes, and the coil winding is embedded between the heat dissipation holes.

3. A statorless axial flux hub generator for electric vehicles according to claim 1 or 2, characterized in that, The manufacturing method of the coil array disk is as follows: First, the coil winding is evenly and flatly arranged on the disk and placed in the potting mold. Then, thermally conductive resin material is poured into the mold to completely wrap the coil winding and form it. After baking and curing, the coil array disk is formed after demolding.

4. A statorless axial flux hub generator for electric vehicles according to claim 1, characterized in that, Both of the magnet array disks include a magnet frame, and a number of N-pole magnets and S-pole magnets are evenly distributed in a circumferential array on the magnet frame. The N-pole magnets and S-pole magnets are arranged alternately along the circumferential direction, and the N-pole magnets and S-pole magnets on the two magnet array disks are respectively paired and arranged opposite each other.

5. A statorless axial flux hub generator for electric vehicles according to claim 1, characterized in that, The magnet array disk adopts a Hellbeck array permanent magnet structure.

6. A statorless axial flux hub generator for electric vehicles according to claim 1, characterized in that, It also includes a motor spindle and a conductive slip ring. The motor spindle is fixed to the vehicle frame, and the conductive slip ring is mounted on the motor spindle and electrically connected to the coil array disk.

7. A statorless axial flux hub generator for electric vehicles according to claim 6, characterized in that, It also includes a wire, and the motor spindle is provided with a wire lead hole, one end of which passes through the wire lead hole and connects to the conductive slip ring.

8. A statorless axial flux hub generator for electric vehicles according to claim 1, characterized in that, Its application is in generating electricity in electric bicycles, electric motorcycles, drones, military and police vehicles, or yachts.

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