Axial Flux Motor

Abstract

The present invention provides an axial flux motor, which includes a stator assembly (10) and rotor assemblies (20) located at both ends of the stator assembly (10), the stator assembly (10) including a stator frame (11) and a plurality of stator cores (12), the stator frame (11) including a bearing stand (111) and a plurality of spokes (113) spaced apart from each other on the bearing stand (111), each spoke (113) including a pair of opposing main surfaces (1133) and a plurality of side edges (1134) connecting the pair of main surfaces (1133), the main surfaces (1133) being perpendicular to the axis of the axial flux motor, and the stator core (12) being fixed between the plurality of spokes (1113).

Description

[Technical Field]

[0001] The present invention relates to the field of motor technology, and more particularly to axial flux motors. [Background technology]

[0002] With the rapid development of new energy vehicles, motor systems, which are an important drive system for new energy vehicles, are also undergoing a period of rapid development. Axial flux motors have many advantages, including high torque density, high efficiency, good heat dissipation performance, and compact axial dimensions, making them the focus of research in the motor field. Summary of the Invention

[0003] The present invention provides an axial flux motor with simplified stator core positioning.

[0004] The present invention provides an axial flux motor including a stator assembly and rotor assemblies located at both ends of the stator assembly, wherein the stator assembly includes a stator frame and a plurality of stator cores, the stator frame includes a bearing stand and a plurality of spokes spaced apart from each other on the bearing stand, each of the spokes including a pair of opposing main surfaces and a plurality of side edges connecting the pair of main surfaces, the main surfaces being perpendicular to an axis of the axial flux motor, and each of the stator cores being fixed between a corresponding one of the plurality of spokes.

[0005] Further, each of the stator cores has a positioning slot on each side surface thereof that fits with the corresponding spokes, the side edges of the corresponding spokes are accommodated in the positioning slot, and the positioning slot is located at the center of the both side surfaces of the stator core. Further, each of the spokes includes a front spoke step provided adjacent to the bearing base and a rear spoke step extending further from the front spoke step, and the width of the front spoke step is greater than the width of the rear spoke step.

[0006] Furthermore, each of the stator cores has a structure having a pole piece on one side, one end of the stator core is a pole piece end, and the other end of the stator core is a pole piece-less end, and the area of ​​the pole piece end is larger than the area of ​​the pole piece-less end.

[0007] Furthermore, the plurality of stator cores include a first set of stator cores and a second set of stator cores that are alternately arranged on the stator frame, with the pole piece ends of the first set of stator cores facing one end of the stator assembly and the pole piece ends of the second set of stator cores facing the other end of the stator assembly.

[0008] Furthermore, the circumferential width of the pole piece end of each of the stator cores is greater than the circumferential distance between two adjacent spokes, and notches are formed between the pole piece end of each of the stator cores and the pole piece-free ends of two adjacent stator cores, and the multiple notches in the stator assembly are of the same size and uniformly distributed.

[0009] Furthermore, the axial flux motor further includes a housing, one ends of the plurality of spokes are fixed to the bearing base and the other ends of the plurality of spokes are fixed to the housing, the stator frame includes a housing connection portion connected to the other ends of the plurality of spokes, and the housing connection portion is attached to the inside of the housing.

[0010] Furthermore, a coolant passage is provided inside the housing, and a water inlet is provided in the housing.

[0011] Furthermore, sealing plates are fixed to both ends of the stator assembly, the sealing plates abut against the stator core, adjacent stator cores form stator slots, an oil channel plate is provided within the stator slots, and the stator core, the sealing plates and the oil channel plates form an oil guide circuit.

[0012] Furthermore, the stator frame includes an annular sleeve provided outside the bearing stand, and the plurality of spokes are uniformly provided on the annular sleeve.

[0013] Furthermore, a steel sleeve is fitted inside the bearing stand, and the material of the annular sleeve and the spokes is a polymer resin-based material.

[0014] Furthermore, the rotor assembly includes a magnetic guide disk and a plurality of permanent magnets provided on the magnetic guide disk, the outer arc surface of the permanent magnets being flush with the outer arc surface of the magnetic guide disk, and the outer arc surface of the magnetic guide disk and the outer arc surface of the permanent magnets being covered with a carbon fiber sleeve formed by winding carbon fiber.

[0015] Furthermore, the stator frame and the stator core are fixed together by epoxy potting.

[0016] Furthermore, each of the stator cores is formed by pressing a soft magnetic composite material, winding an amorphous steel strip, or laminating silicon steel sheets.

[0017] In the present invention, by providing spokes on the stator frame, the stator core can be positioned via the spokes. The positioning method of positioning the stator core between two spokes is simple. At the same time, the spokes can bear the torque and tangential force transmitted from the stator core, improving rigidity.

[0018] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention. [Brief explanation of the drawings]

[0019] The drawings herein are incorporated in and constitute a part of the specification, illustrate embodiments consistent with the present invention, and together with the specification, serve to explain the principles of the invention. [Figure 1]1 is a cross-sectional view of an axial flux motor of the present invention. [Figure 2] 2 is a cross-sectional view of the stator assembly of FIG. 1 mounted in a housing. [Figure 3] 2 is a front view of the stator frame of FIG. 1 attached to a housing. FIG. [Figure 4] FIG. 2 is a perspective view of the stator core of FIG. 1. [Figure 5] 3 is a front view of the stator assembly of FIG. 2 mounted in a housing. DETAILED DESCRIPTION OF THE INVENTION

[0020] Illustrative embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description refers to the drawings, the same numerals in different drawings refer to the same or similar elements unless otherwise noted. It should be noted that the embodiments described in the following illustrative examples do not represent all embodiments consistent with the present invention. On the contrary, they are merely examples of apparatus and methods consistent with certain aspects of the present invention, as set forth in the appended claims.

[0021] The terms used in the present invention are merely for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the specification and claims, the singular forms "a," "the," and "the" are intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term "and / or" used in the present invention means to include any or all possible combinations of one or more of the associated listed items.

[0022] While the present invention may use terms such as "first," "second," and "third" to describe various pieces of information, it should be understood that such information is not limited to these terms. These terms are used only to distinguish between the same types of information. For example, first information may be referred to as "second information," and similarly, second information may be referred to as "first information" without departing from the scope of the present invention. Also, depending on the context, the word "if" used herein may be interpreted as "when," "when," or "in response to a determination."

[0023] YASA has invented a double rotor axial flux motor without a stator yoke, which has the advantages of high efficiency, light weight, and ease of processing. However, because the stator yoke is eliminated and the stator cores are installed separately from each other, positioning the stator cores is difficult.

[0024] In view of this, an embodiment of the present invention provides an axial flux motor.

[0025] 1, the axial flux motor of the present invention includes a stator assembly 10, a rotor assembly 20, and a housing 30. The stator assembly 10 includes a stator frame 11 and a plurality of stator cores 12.

[0026] 2 and 3 , the stator frame 11 includes a bearing base 111, an annular sleeve 112, spokes 113, and a housing connection portion 114. The stator frame 11 can be integrally molded and may include any non-magnetic, non-conductive, and strong material, such as a polymer resin-based material, thereby reducing the weight of the axial flux motor. The stator frame 11 may also be a separate piece, and in this case, the annular sleeve 112, spokes 113, and housing connection portion 114 may also include a polymer resin-based material. A steel sleeve is fitted inside the bearing base 111, and a bearing is provided inside the steel sleeve. Since the steel sleeve has a small amount of thermal deformation, the amount of thermal deformation of the entire stator assembly 10 can be reduced.

[0027] The bearing stand 111 is a stepped cylindrical member and includes a main body 1111 and an end portion 1112 that are coaxially arranged. The inner diameter of the main body 1111 is larger than the inner diameter of the end portion 1112, and the outer diameter of the main body 1111 is larger than the outer diameter of the end portion 1112, thereby forming a step between the inside and outside of the bearing stand 111, which can limit the position of a component such as a bearing mounted on the bearing stand 111. The annular sleeve 112 is a seat and is arranged on the outside of the main body 1111.

[0028] The spokes 113 are mounted on the bearing base 111, with one end fixed to the bearing base 111 and the other end fixed to the housing 30. In this embodiment, the spokes 113 are uniformly arranged on the annular sleeve 112 along the circumferential direction, thereby improving the connection strength between the spokes 113 and the bearing base 111. In other embodiments, the annular sleeve 112 may be omitted, and the spokes 113 are formed to extend radially directly from the bearing base 111.

[0029] Each spoke 113 is a long sheet, and includes a pair of opposing main surfaces 1133 and a plurality of side edges 1134 connecting the pair of main surfaces 1133. The main surfaces 1133 are perpendicular to the axis of the axial flux motor. The multiple spokes 113 are arranged along the circumferential direction on a plane perpendicular to the axis of the axial flux motor and are flush with one another. The plane is located in the center between both end faces of the axial flux motor. The multiple main surfaces 1133 on the same side of the spoke 113 are also flush with one another.

[0030] One end of the spokes 113 is connected to the annular sleeve 112 and extends radially of the bearing base 111. Each stator core 12 is fixed between the corresponding spokes 113. When mounting, positioning is completed simply by abutting the stator core 12 against two adjacent spokes 113, making the operation simple. In addition, the spokes 113 can bear the torque and tangential force transmitted from the stator core 12, improving rigidity.

[0031] The spokes 113 include a front spoke section 1131 disposed adjacent to the bearing base 111 and a rear spoke section 1132 extending further from the front spoke section 1131. A first positioning space 101 is formed between adjacent front spoke sections 1131, and a second positioning space 102 is formed between adjacent rear spoke sections 1132. The width of the front spoke section 1131 is greater than the width of the rear spoke section 1132, and the first positioning space 101 is smaller than the second positioning space 102, allowing the spokes 113 to fit the shape of the stator core 12.

[0032] The housing connection portion 114 is cylindrical and connected to the other end of the spokes 113. The housing connection portion 114 is attached to the inside of the housing 30 and fixes the stator frame 11 to the housing 30 with an interference fit.

[0033] In other embodiments, the housing connection portion 114 and the housing 30 may be fixed to each other by fasteners such as bolts, by fitting protrusions and recesses, or by welding. The housing connection portion 114 may be omitted, and the spokes 113 may be directly connected to and fixed to the housing 30. The stator frame 11 may be die-cast integrally with the housing 30.

[0034] 4, the stator core 12 has a rectangular prism shape with a pole piece on one side. The stator core 12 includes a tooth portion 120 and a pole piece end 121 and a pole piece-less end 122 located at both ends of the tooth portion 120. The tooth portion 120 includes a pair of side surfaces 123, a top surface 124, and a bottom surface 125.

[0035] Positioning slots 126 are provided on both side surfaces 123 of the stator core 12 to fit the corresponding spokes 113. The positioning slots 126 are provided along a plane perpendicular to the axis of the axial flux motor, and a pair of side edges 1134 of the spokes 113 are accommodated in the positioning slots 126. The positioning slots 126 extend from the top surface 124 to the bottom surface 125. The positioning slots 126 are located in the center of both side surfaces 123 of the stator core 12, providing a high fixing effect. The engagement of the positioning slots 126 with the spokes 113 allows for quick positioning and installation of the stator core 12.

[0036] The end faces of the tooth portion 120, the pole piece end 121, and the non-pole piece end 122 are all trapezoidal. The area of ​​the pole piece end 121 is larger than the area of ​​the non-pole piece end 122. Both sides of the pole piece end 121 extend beyond the non-pole piece end 122. A positioning slot 126 is located between the pole piece end 121 and the non-pole piece end 122. After the stator core 12 is mounted on the stator frame 11, the pole piece end 121 and the non-pole piece end 122 are located on both sides of the plane formed by the spokes 113.

[0037] The provision of the pole-piece-free end 122 improves the mounting efficiency of the stator core 12. During mounting, the stator core 12 passes between two adjacent spokes 113 at a position close to the housing 30, and the pole-piece-free end 122 can pass through the first positioning space 101 and the second positioning space 102. After passing through the spokes 113, the stator core 12 is moved radially toward the axis so that the positioning slots 126 on both sides of the stator core 12 are fixed to the side edges 1134, and the teeth 120 abut against the two adjacent spokes 113. A stator winding (not shown) can be mounted on the stator core 12 by passing through the pole-piece-free end 122. An insulating bushing (not shown) is provided between the stator winding and the stator core 12, and the insulating bushing is positioned to avoid the positioning slots 126.

[0038] 5, the multiple stator cores 12 include a first set of stator cores and a second set of stator cores that are alternately arranged on the stator frame 11. Pole piece ends 121 of the first set of stator cores face one end of the stator assembly 10, and pole piece ends 121 of the second set of stator cores face the other end of the stator assembly 10.

[0039] Notches 127 are formed between the pole piece ends 121 of the stator core 12 and the pole piece-free ends 122 of two adjacent stator cores 12. The multiple notches 127 in the stator assembly 10 are uniform in size and uniformly distributed. The circumferential width of the pole piece ends 121 of the stator core 12 is greater than the circumferential distance between two adjacent spokes 113. When viewed axially, the pole piece ends 121 of the stator core 12 overlap the two adjacent spokes 113 and the annular sleeve 112. The width of the notches 127 is small, and is smaller than the width of the spokes 113. The notches 127 also overlap the spokes 113. The staggered arrangement of the stator cores 12 results in uniform, narrow notches 127, which allows for smooth installation of the stator windings and reduces torque pulsation in axial flux motors.

[0040] The stator frame 11 and the stator core 12 are fixed together by epoxy potting. On the one hand, the fixing strength of the stator core 12 can be improved. On the other hand, the rigidity of the stator assembly 10 can be improved, vibration noise can be reduced, and the NVH effect can be improved. At the same time, the poured epoxy has high thermal conductivity, which can improve the cooling speed of the stator core and stator windings, increase motor power, improve power density, and improve the motor's sustained operating ability.

[0041] The stator core 12 can be directly press-molded using a soft magnetic composite material, which simplifies the manufacturing process and increases production efficiency. The soft magnetic composite material has high electrical resistivity and low eddy current loss. When the frequency is higher than 400 Hz, the specific loss of the composite soft magnetic material is low. The stator core 12 may be formed by winding an amorphous steel strip or by laminating silicon steel sheets.

[0042] The rotor assemblies 20 are located at both ends of the stator assembly 10, and form a first air gap 201 and a second air gap 202 between them. The rotor assemblies 20 include a magnetic guide disk 21 and a plurality of permanent magnets 22 provided on the magnetic guide disk 21. The north and south poles of the permanent magnets 22 in the rotor assemblies 20 at both ends are arranged to face each other.

[0043] The magnetic flux starts from the north pole of the rotor assembly 20 at one end, passes through the first air gap 201, the teeth 120 of the stator core 12, and the second air gap 202, enters the south pole of the rotor assembly 20 at the other end, then enters the adjacent north pole through the magnetic guide disk 21, starts from the north pole, passes through the second air gap 202, the teeth 120 of the stator core 12, and the first air gap 201, and returns to the south pole of the rotor assembly 20 at the first end, forming a closed magnetic path.

[0044] The magnetic guide disk 21 is annular, and the permanent magnet 22 is sector-shaped annular. The permanent magnet 22 is positioned on the magnetic guide disk 21 via a shallow groove and fixed with adhesive or plastic sealing. The outer arc surface of the permanent magnet 22 is flush with the outer arc surface of the magnetic guide disk 21.

[0045] The outer arcuate surfaces of the magnetic guide disc 21 and the permanent magnet 22 are covered with a carbon fiber sleeve 23. The carbon fiber sleeve 23 is formed by winding high-strength carbon fiber. The axial width of the carbon fiber sleeve 23 is the same as the sum of the axial thicknesses of the magnetic guide disc 21 and the permanent magnet 22, allowing the magnetic guide disc 21 and the permanent magnet 22 to be enclosed within the carbon fiber sleeve 23. The provision of the carbon fiber sleeve 23 overcomes centrifugal stress that occurs during high-speed rotor operation, enabling high-speed operation of the axial flux motor.

[0046] The axial flux motor of the present invention can employ two cooling methods: water cooling and oil cooling. When water cooling is employed, a coolant passage (not shown) is provided inside the housing 30, and a water inlet 31 is provided in the housing 30.

[0047] When oil cooling is adopted, sealing plates (not shown) are fixed to both ends of the stator assembly 10 and abut against the stator core 12. Adjacent stator cores 12 form stator slots 128, and oil channel plates (not shown) are provided within the stator slots 128. The stator cores 12, sealing plates, and oil channel plates form an oil guide circuit, achieving oil-immersed cooling for the stator core 12 and the stator windings. The material of the sealing plates may be any non-magnetic, non-conductive material, such as glass fiber.

[0048] The above are merely some embodiments of the present invention and do not limit the present invention. Although the present invention has been disclosed above in some embodiments, these embodiments do not limit the present invention. Those skilled in the art can make slight changes or modify equivalent embodiments by using the technical content disclosed above without departing from the scope of the technical solutions of the present invention. However, any simple modifications, equivalent changes and modifications made to the above examples based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention still fall within the scope of the technical solutions of the present invention. Explanation of symbols

[0049] 10—stator assembly, 101—first positioning space, 102—second positioning space, 11—stator frame, 111—bearing base, 1111—main body, 1112—end, 112—annular sleeve, 113—spokes, 1131—front spoke section, 1132—rear spoke section, 1133—main surface, 1134—side edge, 114—housing connection section, 12—stator core, 120—tooth section, 121—pole piece end, 122—pole piece-free end, 123—side, 124—top surface, 125—bottom surface, 126—positioning slot, 127—notch, 128—stator slot, 20—rotor assembly, 201—first air gap, 202—second air gap, 21—magnetic guide disc, 22—permanent magnet, 23—carbon fiber sleeve, 30—housing, 31—water inlet.

Claims

1. An axial flux motor including a stator assembly and rotor assemblies located at both ends of the stator assembly, the stator assembly including a stator frame and a plurality of stator cores, the stator frame including a bearing stand and a plurality of spokes spaced apart from each other on the bearing stand, each spoke including a pair of opposing main surfaces and a plurality of side edges connecting the pair of main surfaces, the main surfaces being perpendicular to an axis of the axial flux motor, and each stator core being fixed between a corresponding one of the plurality of spokes. Axial flux motor.

2. Positioning slots are provided on both side surfaces of each of the stator cores to fit with the corresponding spokes, and the side edges of some of the corresponding spokes are accommodated in the positioning slots, and the positioning slots are located at the centers of the both side surfaces of the stator cores.

2. The axial flux motor of claim 1.

3. Each spoke includes a front spoke section provided adjacent to the bearing base and a rear spoke section extending further from the front spoke section, and the width of the front spoke section is greater than the width of the rear spoke section.

2. The axial flux motor of claim 1.

4. Each of the stator cores has a pole piece on one side, one end of the stator core is a pole piece end, and the other end of the stator core is a pole piece end, and the area of ​​the pole piece end is larger than the area of ​​the pole piece end.

2. The axial flux motor of claim 1.

5. the plurality of stator cores include a first set of stator cores and a second set of stator cores that are alternately provided on the stator frame, the pole piece ends of the first set of stator cores facing one end of the stator assembly, and the pole piece ends of the second set of stator cores facing the other end of the stator assembly; 5. The axial flux motor of claim 4.

6. a width along the circumferential direction of the pole piece end of each of the stator cores is greater than a distance along the circumferential direction between two adjacent spokes, and notches are formed between the pole piece end of each of the stator cores and the pole piece-free ends of two adjacent stator cores, and the sizes of the multiple notches in the stator assembly are the same and are uniformly distributed; 5. The axial flux motor of claim 4.

7. the stator frame further includes a housing, one ends of the spokes are fixed to the bearing base and the other ends of the spokes are fixed to the housing, the stator frame includes a housing connection portion connected to the other ends of the spokes, and the housing connection portion is attached to the inside of the housing.

2. The axial flux motor of claim 1.

8. A coolant passage is provided inside the housing, and a water inlet is provided in the housing.

8. The axial flux motor of claim 7.

9. a sealing plate fixed to each end of the stator assembly, the sealing plate abutting against the stator core, adjacent stator cores forming stator slots, an oil channel plate provided in the stator slots, the stator core, the sealing plate and the oil channel plate forming an oil guide circuit; 8. The axial flux motor of claim 7.

10. The stator frame includes an annular sleeve provided outside the bearing stand, and the plurality of spokes are uniformly provided on the annular sleeve.

2. The axial flux motor of claim 1.

11. A steel sleeve is fitted inside the bearing base, and the material of the annular sleeve and the spokes is a polymer resin-based material.

11. An axial flux motor as claimed in claim 10.

12. The rotor assembly includes a magnetic guide disk and a plurality of permanent magnets provided on the magnetic guide disk, the outer arcuate surfaces of the permanent magnets being flush with the outer arcuate surface of the magnetic guide disk, and the outer arcuate surfaces of the magnetic guide disk and the permanent magnets being covered with a carbon fiber sleeve formed by winding carbon fiber.

2. The axial flux motor of claim 1.

13. The stator frame and the stator core are fixed together by epoxy potting.

2. The axial flux motor of claim 1.

14. Each of the stator cores is formed by press molding of a soft magnetic composite material, winding of an amorphous steel strip, or lamination of silicon steel sheets.

2. The axial flux motor of claim 1.

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