A double-stator single-rotor disc motor

Abstract

The present invention provides a dual-stator, single-rotor disc motor comprising a rotor, two stators, a housing, and two bearings. The stator is a bilaterally symmetrical, slotless, and coreless structure, comprising end caps and windings, wherein the windings are single-layer, concentric, short-pitch windings directly bonded to the end caps with epoxy resin. The rotor is a surface-embedded structure, wherein the rotating shaft is a hollow shaft, integrally formed with the rotor core and rotor frame. The housing and end caps both serve as part of the magnetic circuit. The disc motor of the present invention exhibits no cogging torque or stator core loss, and exhibits excellent heat dissipation, high mechanical strength, and strong reliability, thereby improving the motor's efficiency, overload capacity, and power density.

Description

Technical Field

[0001] The present invention belongs to the technical field of motors, and in particular relates to a double-stator single-rotor disc motor. Background Art

[0002] Disc motors have garnered increasing attention in recent years due to improvements in manufacturing processes and solutions to the unilateral magnetic pull problem. Due to their compact structure, high efficiency, and high power density, they are widely used in applications such as electric vehicles, flywheel energy storage systems, and wind power generation. Existing dual-stator, single-rotor disc motors have separate stator cores and end caps, often secured together by complex locating rings, locating holes, and support brackets. To reduce the magnetic resistance of the motor's magnetic circuit, existing dual-stator, single-rotor disc motors often incorporate a stator core. This unavoidable hysteresis and eddy current losses are particularly severe for motors with a large number of pole pairs and high operating frequencies. The presence of the stator core also causes torque pulsation and noise, hindering smooth operation and efficiency. Traditional motor windings have difficulty dissipating heat. To improve the motor's overload capacity, separate coolant circulation piping is often required, which increases the complexity of motor design. Therefore, it is crucial to find a structural topology that offers high overload capacity, simple structure, reliable operation, and significantly reduced stator core losses.

[0003] Patent CN102130563A proposes a "disk-type permanent magnet motor with a printed circuit board winding structure." By designing the windings as a PCB, this simplifies the stator assembly and motor structure. However, PCB manufacturing is difficult, and the winding current of this structure is limited, making it suitable only for small and medium-power motors.

[0004] Patent CN207625414U proposes a "Halbach-type array permanent magnet disk ironless hollow shaft motor," which improves the motor's power density by incorporating a Halbach structure into the motor structure. However, the motor described in this patent requires brushes because the energized armature disk is a rotating component, which places high demands on the process. Furthermore, the Halbach array is difficult to implement, making engineering difficult. Summary of the Invention

[0005] To overcome the shortcomings of existing dual-stator, single-rotor disc motors, such as high stator core loss and difficulty dissipating heat from the windings, the present invention provides a novel dual-stator, single-rotor disc motor. This motor reduces stator core loss while improving the motor's heat dissipation capacity, thereby enhancing the motor's efficiency and overload capacity.

[0006] A dual-stator single-rotor disc motor includes a rotor, two stators, a housing and two bearings, characterized in that: the stator is a bilaterally symmetrical slotless and coreless structure, including end covers and windings, wherein the end covers serve as stator yokes, the windings are single-layer concentric short-pitch windings with a pitch of 1, and the windings and end covers are directly bonded with epoxy resin; the rotor is a surface-embedded structure, including a rotating shaft, a rotor core, a rotor frame, and magnetic steel, wherein the rotating shaft is a hollow shaft and is an integrally formed structure with the rotor core and rotor frame.

[0007] The rotor core has a through rotor slot for placing the magnet. The depth of the rotor slot is greater than the thickness of the magnet. During installation, the magnet is placed axially into the rotor slot, and an axial gap of equal length is left between the upper and lower surfaces of the magnet and the upper and lower surfaces of the rotor slot, and is encapsulated with epoxy resin.

[0008] Furthermore, the end cover includes a recessed platform, an end cover disk and an end cover edge, wherein the recessed platform is used to place the bearing and limit its axial position, the end cover disk is used to place the winding and serve as the stator yoke, and the end cover edge is used to connect to the casing.

[0009] Furthermore, the magnetic steel adopts a fan-shaped structure, the magnetization direction is axial, and the magnetization directions of two adjacent magnetic steels along the circumferential direction are opposite.

[0010] Furthermore, the winding is composed of a plurality of concentric coils, the two ends of a single coil are concentric arcs with equal radians, the extension lines of the two element sides intersect at the center of the concentric arcs, and the mechanical angle θ corresponding to the coil end arc satisfies Where p is the number of motor pole pairs and α is the pole arc coefficient of the motor.

[0011] Furthermore, the motor has two magnetic flux paths, one is any magnetic steel A—air gap—end cover—air gap—magnetic steel A, a circumferentially adjacent magnetic steel—air gap—end cover—air gap—magnetic steel A, and the other is any magnetic steel A—air gap—end cover—housing—end cover—air gap—magnetic steel A.

[0012] The beneficial effects of the present invention are as follows: due to the slotless and coreless structure, there is no cogging torque and stator core loss; because the casing and the end cover both serve as part of the magnetic circuit, the performance of the ferromagnetic material is fully utilized and the power density is improved; because the winding is a single-layer structure and is directly bonded to the end cover, the heat dissipation performance is excellent and the overload capacity of the motor can be improved; because the rotating shaft, the rotor core and the rotor frame are an integrated structure, the mechanical strength is high and the reliability is strong. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic structural diagram of a dual-stator single-rotor disc motor according to the present invention;

[0014] Figure 2 Schematic diagram of the end cap and the effective side of the winding of the present invention;

[0015] in, Figure 2 a is an isometric drawing, Figure 2 b is a top view, Figure 2 c is the main view;

[0016] Figure 3 A schematic diagram of a coil of the present invention;

[0017] Figure 4 This is a schematic diagram of the stator assembly of the present invention;

[0018] Figure 5 This is a schematic diagram of the assembly of the rotor portion of the present invention;

[0019] In the figure, 1-end cover, 2-casing, 3-rotor core, 4-rotating shaft, 5-bearing, 6-winding, 7-magnet, 11-recess, 12-end cover disk, 13-end cover edge, 21-casing edge, 31-rotor slot, 32-rotor frame, 61-coil. DETAILED DESCRIPTION

[0020] The present invention is further described below with reference to the accompanying drawings and examples. The present invention includes but is not limited to the following examples.

[0021] like Figure 1 As shown, the disc motor structure of the present invention includes an end cap 1, a housing 2, a rotor core 3, a rotor frame 32, a rotating shaft 4, bearings 5, windings 6, and magnets 7. To reduce thickness and weight, the end cap 1 and housing 2 are both made of 1J22 material. To minimize machining difficulty, the rotor core 3, rotor frame 32, and rotating shaft 4 are integrally formed, forged from a single piece of cast iron or steel. The magnets 7 are made of neodymium iron boron (NdFeB) and are embedded in the surface of the rotor core to reduce its axial length.

[0022] like Figure 2 As shown in Figures 2a, 2b, and 2c, the end cap disc 12 is the area between the concave platform 11 and the end cap edge 13. The winding 6 is a single-layer concentric winding composed of multiple coils. The projections of the coils 61 on the end cap 1 are all located within the end cap disc 12 area, with a certain margin left from the outermost edge of the end cap disc 12. A certain axial gap is reserved between the winding 6 and the end cap disc 12 for epoxy resin bonding and potting.

[0023] like Figure 3 As shown, the two ends of a single coil 61 are concentric arcs with equal arc lengths. The extension lines of the two element sides intersect at the center of the concentric arcs. Therefore, the electrical angle spanned by a single coil 61 is the product of the mechanical angle θ corresponding to the arc-shaped end and the number of motor pole pairs p. If the motor pole arc coefficient is α, then in order to ensure that each coil 61 generates effective torque, it should satisfy

[0024] like Figure 4 As shown, both end covers 1 have an end cover edge 13, the shape of which corresponds to the shape of the casing edge 21, and its purpose is to ensure that the end cover 1 and the casing 2 fit together during assembly.

[0025] like Figure 1 、 5 As shown, the rotor core 3 has a through-hole rotor slot 31. The raised portion between the inner diameter of the rotor slot 31 and the outer diameter of the rotating shaft 4 is the rotor frame 32. The rotor slot 31 is used to accommodate the magnets 7. The magnets 7 are magnetized axially and have a fan-shaped shape. Adjacent magnets 7 have opposite magnetization directions along the circumference. The depth of the rotor slot 31 is slightly greater than the thickness of the magnets 7. During installation, the magnets 7 are placed axially into the rotor slot 31. The upper and lower surfaces of the magnets 7 and the upper and lower surfaces of the rotor slot 31 have equal axial clearances. This axial clearance is sealed with epoxy resin.

[0026] like Figures 1 to 5 As shown, this motor has two main magnetic circuits. Because two circumferentially adjacent magnetic steels 7 have opposite polarities, they form a closed magnetic circuit with the air gaps and end caps 1 facing each other. This magnetic circuit (referred to as magnetic circuit 1) accounts for the majority of the main magnetic circuit. A smaller portion of the magnetic circuit (referred to as magnetic circuit 2) is closed by a single magnetic steel 7, the housing 2, the air gaps facing the magnetic steel 7, and the end caps 1. Magnetic circuit 1 contains four air gaps and two magnetic steels 7, while magnetic circuit 2 contains one magnetic steel 7 and two air gaps.

[0027] like Figure 1 、 2 As shown in Figures 2a, 2b, 2c, 4, and 5, the flat wire is first wound into a concentric single-layer winding 6, which is then bonded to the end cover disk 12 with epoxy resin. The magnetic steel 7 is then axially placed into the rotor slot 31 and bonded with epoxy resin. The rotor core 3, rotor frame 32, and rotating shaft 4 are integrally formed. The rotating shaft 4 is fixed to the inner ring of the bearing 5. The bearing 5 is placed on the concave platform 11 of the end cover 1. The rotor frame 32 and the concave platform 11 jointly limit the axial position of the bearing 5. The casing 2 and the end cover 1 are bonded or welded together through the casing edge 21 and the end cover edge 13 with corresponding shapes.

Claims

1. A dual-stator single-rotor disc motor, comprising a rotor, two stators, a housing, and two bearings, characterized in that: The stator is a bilaterally symmetrical slotless and coreless structure, consisting of end caps and windings. The end caps serve as the stator yoke, and the windings are single-layer concentric short-pitch windings with a pitch of 1. The windings and end caps are directly bonded with epoxy resin. The rotor is a surface-embedded structure, consisting of a rotating shaft, rotor core, rotor frame, and magnets. The rotating shaft is a hollow shaft, integrally formed with the rotor core and rotor frame. The rotor core has a through rotor slot for placing the magnet. The depth of the rotor slot is greater than the thickness of the magnet. During installation, the magnet is placed axially into the rotor slot, and an axial gap of equal length is left between the upper and lower surfaces of the magnet and the upper and lower surfaces of the rotor slot, and is encapsulated with epoxy resin.

2. The dual-stator single-rotor disc motor according to claim 1, characterized in that: The end cover includes a recessed platform, an end cover plate and an end cover edge, wherein the recessed platform is used to place the bearing and limit its axial position, the end cover plate is used to place the winding and serve as the stator yoke, and the end cover edge is used to connect with the casing.

3. A dual-stator single-rotor disc motor according to claim 1 or 2, characterized in that: The magnetic steel adopts a fan-shaped structure, the magnetization direction is axial, and the magnetization directions of two adjacent magnetic steels along the circumferential direction are opposite.

4. A dual-stator single-rotor disc motor according to claim 1, 2 or 3, characterized in that: The winding is composed of several concentric coils. The two ends of a single coil are concentric arcs with equal radians. The extension lines of the two element sides intersect at the center of the concentric arcs. The mechanical angle θ corresponding to the arc at the coil end satisfies Where p is the number of motor pole pairs and α is the pole arc coefficient of the motor.

5. A dual-stator single-rotor disc motor according to claim 1, 2, 3 or 4, characterized in that: The motor has two magnetic flux paths, one is any magnet A—air gap—end cover—air gap—magnet A, the circumferentially adjacent magnet—air gap—end cover—air gap—magnet A, and the other is any magnet A—air gap—end cover—housing—end cover—air gap—magnet A.

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