A dual rotor brushless motor

Abstract

The patent discloses a double-rotor single-stator brushless motor, which comprises a first rotor, a stator and a second rotor, and the main structural features are a circular ring-shaped stator core, a first wire slot and a second wire slot are designed, the two kinds of wire slot numbers are equal, the opening directions are opposite, and the positions are alternately and uniformly arranged; the winding form in the wire slot comprises three combined configuration modes of cross-slot winding, cross-half-slot winding and half-slot winding respectively. The motor has a unique induction voltage curve, and has the advantages of easy manufacturing, high reliability, strong overload capacity and wide voltage adaptability.

Description

Technical Field

[0001] This patent relates to a dual-rotor, single-stator brushless motor. In particular, it relates to a motor with high power density and high speed. Background Technology

[0002] Dual-rotor single-stator brushless motors have attracted attention due to their high power density, high torque density, and lightweight, compact design. These advantages make them highly promising for advanced applications in aerospace and high-performance industrial equipment. A dual-rotor single-stator motor consists of two rotors and one stator, with the stator interacting with both rotors simultaneously, resulting in higher performance compared to a single-rotor structure. For example, application number CN201680005613.1 mentions an axial flux motor using this structure, which significantly improves motor performance in vehicles. However, this type of motor presents a technical challenge: integrating the segmented stator teeth into a single unit, which limits its application scope. In applications such as model aircraft and aviation, motors require even higher and stronger technical performance indicators, as well as ease of manufacturing and reliable use; therefore, more suitable motor integration solutions are always in demand. Summary of the Invention

[0003] To achieve the above objectives, the present invention provides a brushless motor solution incorporating advanced technologies in its stator, slots, windings, and overall structure, as detailed below: A dual-rotor brushless motor includes a first rotor, a stator, and a second rotor. The stator includes an iron core and windings. The iron core is annular and has a first slot and a second slot. The two slots have opposite opening directions, equal numbers that are multiples of 3, and are evenly arranged in alternating positions. The windings are placed in the slots.

[0004] When the motor is a radial motor: The first slot is an outer slot that opens outwards and is evenly distributed along the radial outer ring of the iron core. The second slot is an inner slot that opens inwards and is evenly distributed along the inner ring. The inner and outer rings may overlap in radius, but the positions of the inner and outer slots are uniformly staggered. The first rotor is an outer rotor that is radially outside the outer slots, including an outer back rail and multiple outer magnets that are evenly attached to the inside of the outer back rail. The second rotor is an inner rotor that is radially inside the inner slots, including an inner back rail and multiple inner magnets that are evenly attached to the outside of the inner back rail. The magnets are radially magnetized, and adjacent magnets on the back rail have opposite pole directions. The number of inner and outer magnets is equal.

[0005] One solution to enhance heat dissipation is as follows: An airflow source channel of the perforated type is located above the inner rotor where it is fixed to the shaft; alternatively, an airflow source channel is located near the shaft on the motor base. The outer rotor, inner rotor, and the upper part of the stator axially are designed as an inverted U-shaped enclosed fixing device, with a gap between this inverted U-shape and the stator, forming an inverted U-shaped airflow channel. When the motor rotor rotates, it drives the airflow to rotate, and centrifugal force causes the airflow to flow through the airflow channel, thereby carrying away the heat from the stator and rotor. The inverted U-shaped enclosed fixing device has a radially downward-protruding strip at the top near the stator, which is an optional solution to enhance airflow rotation. The gap between adjacent magnets on the back rail is an optional solution to increase airflow speed and volume.

[0006] When the motor is an axial motor: The first slot is an upper slot with an upward opening, evenly distributed along the upper part of the iron core axis. The second slot is a lower slot with a downward opening, evenly distributed along the lower part of the core axis. The upper and lower slots may overlap in some areas, but their positions are uniformly staggered. The first rotor is an upper rotor located axially above the upper slot, comprising an upper back rail and multiple upper magnets evenly abutting the underside of the upper back rail. The second rotor is a lower rotor located axially below the lower slot, comprising a lower back rail and multiple lower magnets evenly abutting the upper back rail. The magnets are axially magnetized, with adjacent magnets on the back rail having opposite pole directions, and the number of upper and lower magnets is equal. The upper and lower rotors are fixedly connected radially outside the stator. Both rotate simultaneously. This fixed connection has radially open slots; when the rotors rotate, these slots act like centrifugal fan blades, driving airflow radially outward to remove heat from the motor.

[0007] Furthermore, the motor also integrates an electronic speed controller (ESC). The stator and the ESC are fixedly connected. The ESC includes a heat sink, which is mainly made of aluminum, copper, or other high thermal conductivity materials. When the motor is a radial motor: the radiator is located inside the inner rotor, and there is a gap between it and the inner rotor. The rotation of the rotor drives the airflow in the gap to move circumferentially, radially and vertically, which can guide and enhance the heat dissipation of the radiator.

[0008] When the motor is an axial motor: the lower part of the lower rotor has radial strip-shaped downward protrusions. The radiator is located below the lower rotor and there is a gap between it and the lower rotor. When the lower rotor rotates, its radial strip-shaped protrusions drive the airflow to flow circumferentially and radially, which can guide and enhance the heat dissipation of the radiator.

[0009] One cross-slot winding design is as follows: each first slot corresponds to one and only one adjacent second slot, used to place a toroidal coil to form a winding.

[0010] Another winding design scheme is as follows: each slot includes two parts, slot A and slot B, which are arranged vertically, horizontally, or in a mixed manner. The correspondence between the windings and the slots is either a cross-slot winding method or a separate half-slot winding method, wherein: The cross half-slot winding method refers to the following: each first slot A corresponds to one and only one adjacent second slot B, and slot B corresponds to one and only one adjacent second slot A. The corresponding slots are used to place the toroidal coil to form a winding. The separate half-slot winding method means that: each first slot A corresponds to only one adjacent first slot B, and is used to place a toroidal coil to form a first winding; each second slot A corresponds to only one adjacent second slot B, and is used to place a toroidal coil to form a second winding.

[0011] A further heat dissipation solution is to design slots A and B of the same wire groove side by side in the opening direction, with a gap between slots A and B for ventilation and heat dissipation. Another solution for connecting the iron core to the motor base is to have a U-shaped opening in the wire groove, with a connecting and fixing device for the base designed in the gap at the middle of the U-shaped bottom of all or part of the wire groove ends.

[0012] The shape and volume of the motor core can be designed to include one of the following two features: Firstly, the cross-sectional area of ​​the magnetic channels at all points in the iron core is matched with the same value.

[0013] Secondly, the magnetic channel cross-sectional area of ​​the iron core connecting teeth of different types of grooves is matched with a specified value. The minimum circumferential cross-sectional area of ​​the iron core at the tooth position mainly serves to connect and fix, and its magnetic flux channel cross-sectional area is less than this value.

[0014] The magnetic channel cross-sectional area matching described in this article refers to the requirement that the required core area is not less than a specified value when considering the propagation of the magnetic field through the core, given a set magnetic density value.

[0015] The relationship between the motor core, its slots, and windings can be summarized as follows: The windings and slots are connected in a half-slot winding configuration. The motor is a three-phase motor, with each phase consisting of a phase unit. A phase unit refers to either a phase unit 1 formed by connecting a specified number of adjacent first windings, or a phase unit 2 formed by connecting a specified number of adjacent second windings. Each phase of the motor includes an equal number of phase units 1 and phase units 2. When a phase unit includes only one winding, phase units 1 and 2 of the same phase are staggered evenly in the circumferential angle position, and the magnetic deviation angles of the nearest corresponding magnets are the same, with the magnetic pole directions being the same or opposite. When a phase unit includes two or more windings, phase units 1 and 2 of the same phase are staggered evenly in the circumferential angle position as much as possible, and the magnetic deviation angles of the corresponding magnets are all the same, with the magnetic pole directions being all the same or opposite. One volume shape scheme is as follows: the main structure of the winding's central iron core is a solid tooth, and the tooth is connected to the opposite teeth on both sides of the slot by a Y-shaped iron core. The sum of the magnetic channel cross-sectional areas of the two Y-shaped iron cores matches the magnetic channel cross-sectional area of ​​one tooth.

[0016] In a dual-rotor radial motor, the outer magnet is typically larger and has a stronger magnetic force than the inner magnet. One scheme to optimize the number of turns in the radial motor coil is to have a larger number of turns in the first winding than in the second winding, wherein the number of turns in the first winding matches the magnetic flux requirement of the outer magnet, and the number of turns in the second winding matches the magnetic flux requirement of the inner magnet. Beneficial effects

[0017] As shown in the above technical solution, the main features of this patent are the uniformly staggered arrangement of the first and second slots to form a composite magnetic circuit, and the staggered winding phase design in the two types of slots at the closest angular positions. The main response of the induced voltage waveform of the motor to the current is significantly different from that of single-rotor motors, split-stator dual-rotor motors, and H-shaped stator dual-rotor motors. It is no longer primarily a change in amplitude, but rather a change in phase, resulting in a significant advantage: extremely strong instantaneous overload capacity and wider voltage adaptability. This patent also has other characteristics and advantages, which will be explained in the implementation examples in the patent document in conjunction with specific situations. Attached Figure Description

[0018] Appendix Figure 1 A horizontal cross-sectional schematic diagram of a radial motor with a cross-slot winding method.

[0019] Appendix Figure 2 : A side view of a radial motor with a cross-slot winding method.

[0020] Appendix Figure 3 A horizontal cross-sectional schematic diagram of a radial motor with a cross-slot winding configuration.

[0021] Appendix Figure 4 A horizontal cross-sectional schematic diagram of a radial motor with a separate half-slot winding configuration.

[0022] Appendix Figure 5 A schematic diagram of the axial discrete structure of an axial motor with a cross half-slot winding method.

[0023] Appendix Figure 6 : An enlarged schematic diagram of the stator section of an axial motor with a cross-slot winding method.

[0024] Appendix Figure 7 A schematic diagram of an axial motor with a separate half-slot winding method.

[0025] Appendix Figure 8 A schematic diagram of an annular cross-section of an axial motor with a half-slot winding configuration.

[0026] Appendix Figure 9 A simulation diagram of the induced voltage waveform of an axial motor with a half-slot winding configuration. Implementation

[0028] Generally, dual-rotor motors have stronger overall performance than single-rotor motors. Dual-rotor motors are mainly divided into radial motors and axial motors. This patent solution is applicable to both radial and axial motors. In the following implementation description, the main principles and methods of one type of motor embodiment are also applicable to the other type of motor. Those skilled in the art can infer this from the description, so it will not be elaborated further.

[0029] The basic structure of the motor described in this patent is as follows: a brushless motor, including a first rotor, a stator, and a second rotor. The stator includes an iron core and windings. The iron core is annular and has a first slot and a second slot. The opening directions of the two types of slots are opposite, their number is equal and a multiple of 3, and their positions are alternately staggered and evenly arranged. The windings are placed in the slots. The following five embodiments are described in detail.

[0030] Example 1: Radial motor with inner and outer cross-slot windings.

[0031] As attached Figure 1As shown, a horizontal cross-sectional diagram of a radial brushless permanent magnet motor is presented. The stator core 103 is a ring-shaped integral unit. The outer ring has 18 radially evenly distributed outward-opening outer slots 104, and the inner ring has 18 radially evenly distributed inward-opening inner slots 105. The inner and outer slots overlap in some areas, but their positions are evenly staggered. The outer slots radially face outward towards the rotor and include an integral ring-shaped outer back rail 102 and 12 outer magnets 106 evenly attached to the inside of the outer back rail. The inner slots radially face inward towards the inner rotor and include an integral ring-shaped inner back rail 101 and 12 inner magnets 107 evenly attached to the outside of the inner back rail. The magnets are radially magnetized, and adjacent magnets on the back rail have opposite pole directions. The pole-to-slot ratio of the motor is set to 2:3, the number of magnets on one side of the rotor is 12, and the number of teeth on one side is 18. The first rotor, the second rotor, and the stator are coaxial rings, and their various positions are connected to the shaft center, forming an angle. Figure 1 When one stator tooth of the motor is connected to the shaft center by an adjacent slot on the same side, an angle of 360 / 18=20 degrees is formed. The nearest outer magnet 106 and inner magnet 107 have a deviation of half of this angle value, that is, 10 degrees. The magnetic poles of both facing the middle stator are in the same direction, which is the N pole.

[0032] As attached Figure 1 The motor winding design is illustrated as follows: Three phases (U, V, W) with 10 windings per phase, designated U1-U10, V1-V10, and W1-W10 respectively. The cable for one winding forms a loop through two slots. The slots are suffixed with + and - to indicate the current sequence is output and input current, respectively. One slot is for external wiring, and the other is for internal wiring; they are adjacent to each other, as shown in the attached diagram. Figure 1 The symbols U1+ and U1-, V1+ and V1-, and W1+ and W1- represent the two slots and their current states of the first winding of the current UVW three-phase system, respectively. Similarly, U2+ and U2-, V2+ and V2-, and W2+ and W2- represent the two slots and their current states of the second winding of the current UVW three-phase system. The division of the windings into UVW three phases as described in this patent does not imply that the windings must be driven by a sinusoidal three-phase AC current; a three-phase chopper drive is a good alternative.

[0033] The three-phase windings are connected in a star configuration. Multiple windings of the same phase can be connected in series, parallel, or a combination of series and parallel. The motor's main power-generating method is as follows: all three phase windings carry current, with one phase winding being the primary energized and the other two phase windings being equally distributed and energized in opposite directions. The primary energization can be achieved by the current flowing from the outer slot to the inner slot, or vice versa; the equally distributed and reversed energization means that the current direction is opposite to the primary energization direction, and the current magnitude is an average distribution of the primary energized current. (See attached diagram.) Figure 1As shown, the magnetic field lines generated by the energized coil in the iron core mainly consist of two types. One type, such as magnetic field line 142, originates from the inner back rail, passes through the first inner tooth, the first outer tooth, the second inner tooth, then the second outer tooth, and finally reaches the outer back rail. This magnetic field line passes through two winding coils, matching the two phases that are energized in opposite directions. The other type, such as magnetic field line 141, originates from the outer back rail, passes through one outer tooth and one inner tooth, and directly reaches the inner back rail. This magnetic field line passes through only one winding, matching the one phase that is mainly energized. The two types of magnetic field lines are joined together in the back rail to form a loop, creating a circuit.

[0034] Appendix Figure 1 As shown in the current timing state, all three phase windings are energized. The W-phase winding is mainly energized, and the UV-phase windings are equally energized in reverse, generating a magnetic field in the core. Figure 1 With the magnet configuration shown, the motor rotor will rotate clockwise. When it reaches the next position (0.5 phases), the V-phase winding coil reverses its energizing direction, and the U-phase winding becomes the main energizer, while the V and W-phase windings are equally energized in the opposite direction. The motor rotor will continue to rotate clockwise. In the next sequence, the W-phase winding coil reverses its energizing direction, the V-phase becomes the main energizer, and the U and W-phases are equally energized in the opposite direction, and the rotor continues to rotate. This energizing process repeats continuously, ensuring the motor rotor continues to rotate.

[0035] The magnetic field generated by the motor windings interacts with the magnetic field of the magnet, and its magnetic field lines cover most of the iron core. In this embodiment, it is assumed that the magnetic field lines flow uniformly and equally along the annular iron core, so the magnetic flux cross-sectional area is designed to be the same at all locations of the annular iron core.

[0036] In this embodiment, the side view of the motor is shown in the attached figure. Figure 2 As shown, in conjunction with the appendix Figure 1 The location codes 101, 102, 103, 106, 107, and 130 respectively point to the inner back rail, outer back rail, iron core, outer magnet, inner magnet, and motor shaft. (See attached image.) Figure 2 As shown: the inner back rail 101 and outer back rail 102 are integrated into a single unit on the upper part of the motor stator. 120 is the main body of the aluminum heat sink, and 121 points to the radial blades of the aluminum heat sink, with the radial ends of the blades close to the inner rotor. 140 is an opening at the top of the motor, providing an airflow channel. (See attached image) Figure 2As shown, a complete airflow channel is formed by the gaps between the opening 140, the aluminum heat sink blades 121 and the inner back rail 101, the inner magnet 107 and the stator core 103, the stator core 103 and the top of the motor, and the stator core 103 and the outer magnet 106. When the motor rotor rotates, due to centrifugal force, air flows rapidly along the airflow channel, which can carry away the heat of various components in the channel, including the stator, including the heat of the intermediate aluminum heat sink. An electronic speed controller (ESC) is installed at the bottom of the aluminum heat sink. When motors in some aircraft models operate at high speed and high power, the ESCs of brushless motors often generate a lot of heat. In this embodiment, the space inside the inner rotor is fully utilized to install the aluminum heat sink, and the rotor rotation is used for rapid heat dissipation. In motor applications where weight and space are very sensitive, this implementation scheme has great advantages.

[0037] In the above embodiment, the main advantages include: simultaneous energization of all three phases to perform work improves winding utilization and reduces copper loss compared to the usual driving method where only two phases are energized.

[0038] Example 2: Radial motor with interlaced half-slot windings. Details are similar to Example 1, and the similarities may not be elaborated further.

[0039] As attached Figure 3 As shown: In this case, each slot is arranged counterclockwise along the opening direction, comprising two parts: slot A and slot B. For example, the outer slot is divided into slots 222 and 221, and the inner slot is divided into slots 224 and 223. A winding requires two slots: slot A of the outer slot and slot B of the adjacent inner slot, or slot B of the outer slot and slot A of the adjacent inner slot. The slot arrangement of the UVW three phases of the entire stator winding is shown in the attached diagram. Figure 3 As shown, they are arranged sequentially according to the slot position: U1A, U1B, V1A, V1B, W1A, W1B, U2A, U2B, V2A, V2B, W2A, W2B, and so on, until W20A (not marked) and W20B (not marked). In the code, the first digit indicates the three-phase distinction of UVW, the second digit indicates which winding coil, and the third digit A indicates slot A and B indicates slot B.

[0040] like Figure 3As shown, each slot contains three circles, indicating the number of turns in a winding coil. The smaller circles contain "+", "-", or blank markings to indicate the current state of the winding coil at the current time, i.e., current output, current input, and no current. Based on the energizing states of each coil in the diagram, the generated magnetic field lines mainly fall into two categories: one, such as magnetic field line 231, flows from the outer rail to the outer tooth, to the inner tooth, back to the outer tooth, and then back to the outer rail, forming a complete magnetic field line loop. The other, such as magnetic field line 232, flows from the inner rail to the inner tooth, to the outer tooth, back to the inner tooth, and then back to the inner rail, also forming a complete magnetic field line loop.

[0041] In this embodiment, the difference from Embodiment 1 is as follows: Figure 3 As shown, the outer and inner magnets, which are closest to each other, are angularly aligned, and their magnetic poles face the same direction as the middle stator. The three-phase power-on drive method in this embodiment can employ conventional three-phase sine wave drive or chopper drive, technologies that have been mature for decades and will not be elaborated upon here.

[0042] In this embodiment, the division of the slot A and slot B regions of the same groove can also be done in other ways, such as dividing them one above the other in the opening direction, or mixing the regions.

[0043] In the above embodiment, the advantages include simple winding and magnetic circuit, easy winding of coil ends, flexible design of wire groove shape, and wide applicability to various scenarios.

[0044] Example 3: Radial motor, with half-slot windings for both internal and external teeth. Details are similar to Example 1, and the similarities may not be elaborated further.

[0045] In this case study, the cable tray design consists of two sections, slot A and slot B, arranged counter-clockwise in the direction of their openings, along with gaps and partitions. (See attached diagram.) Figure 4 As shown, the trough includes trough A (trough 302), trough B (trough 301), and also includes two gaps 303 and a partition 304 in the middle.

[0046] The phase of the winding coil is set as follows: A winding requires two slots: slots A and B on both sides of one tooth in the outer slot direction; this winding is called the outer winding. Alternatively, slots A and B on both sides of one tooth in the inner slot direction; this winding is called the inner winding. For example... Figure 4 As shown, following the slot sequence, U1A and U1B next to an external tooth form the two slots needed for the first winding of phase U; V1A and V1B next to an adjacent internal tooth form the two slots needed for the first winding of phase V; W1A and W1B next to the next adjacent external tooth form the two slots needed for the first winding of phase W, and so on. There are also slots U2A and U2B, V2A and V2B, and W2A and W2B for the second winding of each of the three phases, ultimately forming all the windings of the UVW three-phase stator of the motor stator. (Appendix) Figure 4 The presence of +, -, or blank spaces within the small circles in the slots indicates that the current in the winding coil is either output current, input current, or no current in the current timing state. The windings of the same phase are connected in series, as shown in the figure. Note that the potential directions of the windings at the outer tooth position and the inner tooth position are opposite. When the outer tooth position is clockwise winding, the inner tooth position is counterclockwise winding, and vice versa.

[0047] In this embodiment, the coil mainly generates four types of magnetic field lines, as shown in the attached diagram. Figure 4 As shown, in the current sequence, an inner magnetic field line 313 is generated, forming a magnetic loop from the inner back rail to the inner tooth, outer tooth, inner tooth, and back to the inner back rail; an outer magnetic field line 311 forms a magnetic loop from the outer back rail to the outer tooth, inner tooth, outer tooth, and back to the outer back rail; a connecting magnetic field line 312 forms from the inner back rail to the inner tooth, outer tooth, and back to the outer back rail; and a connecting magnetic field line 314 forms from the outer back rail to the outer tooth, inner tooth, and back to the inner back rail. The connecting magnetic field lines mix with the inner and outer magnetic field lines in the back rail, forming a mixed loop.

[0048] This embodiment differs from Embodiment 1, as shown in the appendix. Figure 4 As shown, the outer and inner magnets, which are closest to each other, are angularly aligned, and their magnetic poles facing the middle stator are in opposite directions. In the current timing sequence, as... Figure 4 As shown, when the magnetic lines of force combine with the magnets, the motor rotor will rotate clockwise. The complete three-phase power-on drive method in this embodiment can employ conventional three-phase sine wave drive or chopper drive; the technology is extremely mature and will not be elaborated further.

[0049] In this embodiment, the stator core and winding configuration can be optimized in various ways.

[0050] As attached Figure 4 As shown, the magnetic force generated by the outer winding mainly interacts with the outer magnet, while the magnetic force generated by the inner winding mainly interacts with the inner magnet. Therefore, the number of turns in the windings can be optimized: the number of turns in the outer winding should be matched to the magnitude of the magnetic force of the outer magnet, and the number of turns in the inner winding should be matched to the magnitude of the magnetic force of the inner magnet. For example, the ratio of the number of turns in the outer winding to the number of turns in the inner winding, and the ratio of the volume of the outer magnet to the volume of the inner magnet, should be as close as possible. Similarly, the tooth area of ​​the inner and outer teeth of the core can be optimized, such as the ratio of the tooth area of ​​the outer teeth to the tooth area of ​​the inner teeth, and the ratio of the volume of the outer magnet to the volume of the inner magnet, should also be as close as possible.

[0051] As attached Figure 4The diagram shows the magnetic field lines generated by the coils. Magnetic field lines 312 and 314 mainly follow the connection point of the inner and outer teeth and do not pass through a complete tooth. Magnetic field line 313 passes through a complete outer tooth, is mainly driven by the inner winding, and mainly interacts with the inner magnet. Magnetic field line 311 passes through a complete inner tooth, is mainly driven by the outer winding, and mainly interacts with the outer magnet.

[0052] The main advantages of the implementation of separate half-slot windings for internal and external teeth include: four magnetic field lines, which enable almost 100% utilization of the iron core in a single energized power sequence, reducing the amount of iron core material used and iron loss in the motor stator.

[0053] In this implementation, the orientation of the magnetic field lines in the iron core can be mainly considered in terms of the connection between the inner and outer magnets, while the coil windings are mainly considered in terms of the influence of the magnitude and path offset of the magnetic field lines. Therefore, the volume and shape of the iron core can be appropriately optimized accordingly, that is, the cross-sectional area of ​​the magnetic channel of the iron core connecting the inner and outer teeth is matched to a specified value, and the circumferential magnetic flux of the iron core at the tooth position is smaller, and its magnetic channel cross-sectional area is smaller than the specified value.

[0054] Example 4: Implementation of the axial motor cross half-slot winding.

[0055] In the application of this patented technology to axial motors, referring to the previous three radial motor implementation schemes, the inward and outward directions are changed to up and down. It also includes three winding methods: up-and-down cross-slot windings, up-and-down cross-half-slot windings, and up-and-down separate half-slot windings. The details of the winding methods, as well as the magnet configuration, iron core, and magnetic circuit, are essentially the same as the previous three implementation schemes, and can be deduced by those skilled in the art, so further elaboration is unnecessary. This implementation example uses the up-and-down cross-half-slot winding form for illustrated explanation.

[0056] Appendix Figure 5The diagram shows the upper and lower discrete components of an axial motor. Specifically, the motor has an upper and lower axial structure, including an upper rotor with a shaft 501 at its center and an opening 502 on its top. Near the periphery of the upper rotor is an annular upper back rail 503, below which are multiple evenly spaced, tightly attached upper magnets. The periphery of the upper back rail extends downwards, with evenly distributed slots 504 extending along this periphery. In the middle is a stator, including an iron core 511. The iron core has evenly spaced, staggered slots on both the upper and lower sides, and coil windings 512 are placed in these slots. The windings use a combination of upper and lower cross-slot half-slots. A connecting and fixing base 513 is located in the middle and downwards of the stator, and the three-phase winding interface 514 extends downwards. Below the stator is a lower rotor, including multiple evenly spaced, annular lower magnets 521. Below the lower magnets is an annular lower back rail 522, and below the lower back rail are radially convex air guides 523. The motor has a base at its lower part, and the base has a main body 532. An electronic speed controller (ESC) is installed inside the base, which has two power input lines 533 and a communication line 534. The base has radially shaped concave heat dissipation slots 531 made of aluminum. When the motor is running, the large amount of heat generated by the ESC is transferred and concentrated in the aluminum concave heat dissipation slots 531. When the lower rotor rotates, the radially shaped downward-convex air guides 523 of the lower rotor drive the airflow in the gap below to move rapidly in a circumferential and radial direction, quickly dissipating heat from the aluminum concave heat dissipation slots 531.

[0057] Appendix Figure 6 The attached image shows... Figure 5 A detailed enlarged schematic diagram of the stator section of the motor.

[0058] As attached Figure 6 As shown: The base in the middle of the stator has a circular structure, and there is a gap between its outer diameter and the inner diameter formed by the coil wound on the stator core, thereby reducing the electromagnetic influence of the base on the coil and the core.

[0059] As attached Figure 6 As shown, in this embodiment, the stator coil adopts an upper and lower cross-slot combination winding form. Each slot includes two parts, slot A and slot B, with a gap between slot A and slot B. This gap in the axial motor can serve as an airflow channel for ventilation and heat dissipation. Figure 5 As shown, when the rotor rotates, the opening 502 in the middle of the upper rotor serves as an airflow inlet, and the multiple slots 504 extending downward from the periphery of the upper rotor act as centrifugal fan blades, causing the airflow to flow rapidly radially and centrifugally in the gaps of the slots, thereby carrying away the heat of the entire stator.

[0060] The physical connection between the iron core and the motor base needs to be very strong and reliable, as shown in the attached figure. Figure 6As shown, the base has protruding connections 515 at corresponding positions in each upper slot of the iron core, and similarly, protruding connections at corresponding positions in each lower slot. These protruding connections secure the iron core in place and are then encapsulated with epoxy resin after assembly, thus achieving a reliable physical connection between the base and the iron core. The base and the base plate can be fixedly connected, and the winding coils on the iron core are led out through the intermediate base to a three-phase interface 514, connecting to the electrical regulator in the base plate below.

[0061] Appendix Figure 7 This is a schematic diagram of the overall axial motor. The axial motor of this embodiment, in its fully assembled state, is shown in the attached diagram. Figure 7 As shown, the lower rotor and the upper rotor, along with their surrounding periphery, are connected and fixed together. The gap between the radially convex air guide strips at the bottom of the lower rotor and the radially concave heat dissipation grooves at the top of the base is designed to be very small, so as to better dissipate heat from the concave heat dissipation grooves on the base.

[0062] Example 5: Implementation of a half-slot winding system for an axial motor. Details are the same as in the previous examples and will not be repeated here.

[0063] This patented technology is also applicable to axial fractional slot motors. (See attached image) Figure 7 The diagram shows a typical fractional-slot axial motor structure with a pole-to-slot ratio of 24:28. The motor stator core has an outer diameter of 62mm. The motor includes structural components such as the core 601, upper magnet 602, upper back rail 603, lower magnet 604, lower back rail 605, upper winding 606, and lower winding 607. The stator consists of three phases (U, V, W), with each phase comprising four phase units in the upper and lower sections. Each phase unit includes two windings, corresponding to 24 teeth in both the upper and lower sections. The upper and lower sections of the motor also each contain 28 evenly distributed magnets.

[0064] Appendix Figure 8 The diagram shown is a schematic diagram of the annular cross-section of the motor in this embodiment, wherein the attached diagram is shown in the figure. Figure 7 Identifiers with the same code represent the same component.

[0065] As shown in the figure, UT11A and UT11B at half-slot positions form one winding in the upper part of phase U, and the adjacent UT12A and UT12B form another winding. These two windings constitute the first phase unit in the upper part of phase U. Following this sequence, VT11A and VT11B, and VT12A and VT12B form the first phase unit in the upper part of phase V; WT11A and WT11B, and WT12A and WT12B form the first phase unit in phase W; UT21A and UT21B form the first winding of the second phase unit in the upper part of phase U.

[0066] In the half-slot positions, UB11A and UB11B form one winding in the lower part of phase U, and the adjacent UB12A and UB12B form another winding. These two windings constitute the first phase unit in the lower part of phase U. Similarly, VB11A and VB11B, and VB12A and VB12B constitute the first phase unit in the lower part of phase V; WB41A and WB41B, and WB42A and WB42B constitute the fourth phase unit in the lower part of phase W.

[0067] In the phase unit of phase U, the first phase unit at the bottom is located between the first and second phase units at the top. Since there are three tooth positions between them, it is impossible to take the position in the exact middle. In this embodiment, the position of the two teeth on the left is taken, and then the entire lower phase unit is taken in a position slightly to the left.

[0068] In this implementation, the upper and lower phase units of the same phase are set to the same or opposite magnetic deflection positions. For example, if the upper magnets corresponding to slots UT11A and UT11B of the upper winding of phase U are perfectly aligned with the N pole, then the lower magnets corresponding to slots UB11A and UB11B of the lower winding are also perfectly aligned with the N pole. To achieve this purpose, the positions of the upper and lower magnets are offset overall, specifically set to one-seventh of a magnet angle position, such as... Figure 8 As shown, 614 points to the width of a magnet of 7.2mm, and 613 points to the offset width of the upper and lower magnets of 0.6mm.

[0069] In this implementation, such as Figure 8 As shown, there are half-groove positions UT11A and UT11B at the top. The middle iron core tooth is a solid tooth. The width of the tooth is 4.2mm, indicated by 612. The groove is below the tooth. The upper tooth forms a Y shape on both sides of the groove and connects with the lower tooth. The width of the Y-shaped connection is 2.1mm, indicated by 611, which is exactly half the width of the tooth.

[0070] In this implementation, as shown in the appendix Figure 7 As shown, the outer diameters of the upper magnet 602 and the lower magnet 604 are set to 66mm, and the outer diameter of the middle iron core is 62mm. The outer diameter of the magnet is 4mm larger than that of the iron core, which is close to the outer diameter of the iron core after the coil is wound. In the ideal results of computer simulation, the torque increases by as much as 10% compared to the case where the outer diameter of the magnet is 62mm.

[0071] After the magnetic field lines of the N pole of the upper magnet 602 of the motor reach the iron core, there are three possible paths: returning to the upper adjacent magnet S pole, passing through the left iron core branch to reach the lower magnet S pole, and passing through the right iron core branch to reach the lower magnet S pole. At the same time, as can be seen from the three-phase configuration of this embodiment, the phase of the upper part and the nearest lower tooth are not the same, and their maximum magnetic flux density values ​​do not arrive at the same time, with a phase difference of 120 degrees.

[0072] Based on the composite magnetic path and the different phases of the upper and lower teeth described above in this embodiment, the motor in this embodiment has different performance parameters than commonly used motors. In the software simulation test, the motor was set to a fixed speed of 3000 rpm, and each winding coil had 7 turns. The motor produced the following output: Figure 9 The induced voltage waveforms shown are as follows: curves 801, 802, 803, and 804 represent the induced voltage curves of the motor's U-phase under sinusoidal current drives with maximum values ​​of 0A, 20A, 40A, and 60A, respectively. According to these curves, the main response of the motor's induced voltage waveform to current is not primarily through amplitude changes, but rather through phase changes. This results in significantly enhanced instantaneous overload capacity and a wider voltage adaptability.

Claims

1. A dual-rotor brushless motor, comprising a first rotor, a stator, and a second rotor, characterized in that: The stator includes an iron core and windings. The iron core is annular and has a first slot and a second slot. The number of the two types of slots is equal, their opening directions are opposite, and their positions are evenly and alternately arranged. The windings are placed in the slots. The first groove is an outer groove that opens outwards, and the second groove is an inner groove that opens inwards; the first rotor is an outer rotor that is radially outside the outer groove, including an outer back rail and multiple outer magnets that are evenly attached to the inside of the outer back rail; the second rotor is an inner rotor that is radially inside the inner groove, including an inner back rail and multiple inner magnets that are evenly attached to the outside of the inner back rail. Alternatively: the first groove is an upper groove that opens upwards, and the second groove is a lower groove that opens downwards; the first rotor is an upper rotor that is axially above the upper groove, including an upper back rail and multiple upper magnets that are evenly attached to the lower part of the upper back rail; the second rotor is a lower rotor that is axially below the lower groove, including a lower back rail and multiple lower magnets that are evenly attached to the upper part of the lower back rail.

2. The brushless motor according to claim 1, characterized in that: The outer rotor, inner rotor, and the area above the stator axially are designed as an inverted U-shaped closed fixing device, forming an inverted U-shaped airflow channel with the stator. Alternatively: The upper rotor and the lower rotor are fixedly connected on the outer periphery outside the stator radial direction. The outer periphery fixed connection has a radially open slot design. When the rotor rotates, the slot design acts as a centrifugal fan blade, which can drive the airflow outward.

3. The brushless motor according to claim 1 or 2, characterized in that: The motor also integrates an electronic speed controller (ESC), which includes a heat sink. The stator and the ESC are fixedly connected, wherein: The radiator is located inside the inner rotor and there is a gap between it and the inner rotor. The rotation of the rotor can drive the airflow in the gap, which guides and enhances the heat dissipation of the radiator. Alternatively: The lower rotor has radial strip-shaped downward protrusions at the bottom. The radiator is located below the lower rotor and there is a gap between it and the lower rotor. When the lower rotor rotates, its radial strip-shaped protrusions can drive the airflow to flow circumferentially and radially, guiding and enhancing the heat dissipation of the radiator.

4. The brushless motor according to any one of claims 1 to 3, characterized in that: Each first slot corresponds to one and only one adjacent second slot, where a toroidal coil is placed to form a winding.

5. The brushless motor according to any one of claims 1 to 3, characterized in that: each The wire slot consists of two parts, slot A and slot B, which are arranged vertically, horizontally, or in a mixed configuration. The windings correspond to the wire slots in either a cross-slot winding pattern or a separate half-slot winding pattern, wherein: The cross half-slot winding method refers to the following: each first slot A corresponds to one and only one adjacent second slot B, and slot B corresponds to one and only one adjacent second slot A. The corresponding slots are used to place the toroidal coil to form a winding. The separate half-slot winding method means that: each first slot A corresponds to only one adjacent first slot B, and is used to place a toroidal coil to form a first winding; each second slot A corresponds to only one adjacent second slot B, and is used to place a toroidal coil to form a second winding.

6. The brushless motor according to any one of claims 1 to 5, characterized in that: The cross-sectional area of ​​the magnetic channels throughout the iron core is matched to the same value; Alternatively: The magnetic channel cross-sectional area of ​​the iron core connecting teeth of different types of groove directions is matched with a specified value. The minimum circumferential cross-sectional area of ​​the iron core at the tooth position mainly serves to connect and fix, and its magnetic channel cross-sectional area is less than this value.

7. The brushless motor according to claim 5, wherein the correspondence between the windings and the slots is a half-slot winding method, characterized in that: The motor is a three-phase motor, and each phase is composed of phase units. A phase unit refers to a phase unit one formed by connecting a specified number of adjacent first windings, or a phase unit two formed by connecting a specified number of adjacent second windings. Each phase of the motor includes an equal number of phase units one and phase units two. Phase units one and phase units two of the same phase are staggered as evenly as possible in the circumferential angle position, and the corresponding magnets have the same magnetic deviation angle and the same or opposite magnetic pole directions.

8. The brushless motor according to claim 7, characterized in that: The main structure of the winding's central core is a solid tooth. The tooth is connected to the opposite teeth on both sides of the slot by a Y-shaped core. The sum of the magnetic channel cross-sectional areas of the two Y-shaped cores matches the magnetic channel cross-sectional area of ​​one tooth.

9. The brushless motor according to any one of claims 5 to 8, characterized in that: Slots A and B of the same trough are designed side by side in the opening direction, with a gap in the middle, which can be used for ventilation and heat dissipation.

10. The brushless motor according to any one of claims 5 to 9, characterized in that: The number of turns in the first winding is greater than the number of turns in the second winding, wherein the number of turns in the first winding matches the magnetic flux requirement of the outer magnet, and the number of turns in the second winding matches the magnetic flux requirement of the inner magnet.

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