Stator, rotating electric machine, and method for manufacturing a stator
The innovative design of the stator with divided stator cores and case components in axial-gap type rotating electric machines narrows the gap between the stator core and rotor, enhancing torque and heat dissipation, and facilitating wire connections.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- MITSUBISHI ELECTRIC CORP
- Filing Date
- 2024-12-20
- Publication Date
- 2026-07-02
AI Technical Summary
Conventional stators in axial-gap type rotating electric machines have a wide gap between the stator core and the rotor, leading to low torque characteristics.
The stator is designed with a plurality of stator cores and a stator case, where the stator cores are divided into two parts in the axial direction, with flange portions having a larger cross-sectional area than the winding portions, and the stator case is also divided into two parts, positioning the flanges axially outward from the case bottoms, allowing for a narrower gap between the stator core and the rotor.
This configuration improves torque characteristics and enhances heat dissipation by narrowing the gap between the stator core and the rotor, while also allowing for improved workability in connecting terminal wires and coolant flow.
Smart Images
Figure 2026109777000001_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to a stator, a rotating electric machine, and a method for manufacturing a stator.
Background Art
[0002] As a thin rotating electric machine, an axial-gap type rotating electric machine in which a disk-shaped stator and a rotor are arranged to face each other in the axial direction is known. As a stator of a conventional axial-gap type rotating electric machine, a structure is disclosed in which a support plate that holds a stator core made of a compressed powder body from both sides in the axial direction is provided, and this support plate is fixed to the frame of the stator (see, for example, Patent Document 1). Further, as another stator, a stator core made of a compressed powder body has a plurality of teeth and an annular back yoke arranged on the outer peripheral side of the teeth, and the teeth are inserted into a groove of the back yoke provided in the circumferential direction from the axial direction and fixed to the back yoke. A structure is disclosed (see, for example, Patent Document 2).
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Patent Document 2
Summary of the Invention
Problems to be Solved by the Invention
[0004] In a conventional stator, since a support plate or a back yoke is arranged between the stator core and the rotor, there is a problem that the gap between the stator core and the rotor cannot be narrowed. Therefore, in a conventional axial-gap type rotating electric machine, there is a problem that the torque characteristics are low.
[0005] This disclosure was made to solve the above-mentioned problems and aims to provide a rotating electric machine that can narrow the gap between the stator core and the rotor and has high torque characteristics. [Means for solving the problem]
[0006] The stator of this disclosure is a stator comprising a plurality of stator cores made of a magnetic material, a plurality of coils wound around each of the plurality of stator cores, and a stator case made of a non-magnetic material that fixes the plurality of stator cores in an annular arrangement, wherein the stator core has a winding portion around which the coils are wound and flange portions at both ends of the winding portion in the axial direction, and the stator core is composed of a first stator core and a second stator core that are divided into two in the axial direction, with the area of the cross-section of the flange portion perpendicular to the axial direction being larger than the area of the cross-section of the winding portion perpendicular to the axial direction, and the stator case has two annular bottom portions having a plurality of through holes through which the winding portions of the plurality of stator cores can each pass, and a cylindrical portion that fastens the outer diameter portions of the two bottom portions in the axial direction, and the stator case is composed of a first stator case and a second stator case that are divided into two in the axial direction, with the flange portions at both ends of the stator core in the axial direction being positioned axially outward from the two bottom portions of the stator case. [Effects of the Invention]
[0007] In the stator of this disclosure, the flanges at both axial ends of the stator core are positioned axially outward from the two bottoms of the stator case, thereby narrowing the gap between the stator core and the rotor. As a result, the torque characteristics of a rotating electric machine equipped with this stator can be improved. [Brief explanation of the drawing]
[0008] [Figure 1] This is a cross-sectional view of a rotating electric machine according to Embodiment 1. [Figure 2] This is a top view of the stator according to Embodiment 1. [Figure 3] This is a cross-sectional view of the stator according to Embodiment 1. [Figure 4]This is an exploded view of the stator according to Embodiment 1. [Figure 5] This is a diagram illustrating the assembly procedure for the stator according to Embodiment 1. [Figure 6] This is a diagram illustrating the assembly procedure for the stator according to Embodiment 1. [Figure 7] This is a diagram illustrating the assembly procedure for the stator according to Embodiment 1. [Figure 8] This is a perspective view of the stator according to Embodiment 2. [Figure 9] This is a perspective view of the stator according to Embodiment 2. [Figure 10] This is a cross-sectional view of the stator according to Embodiment 3. [Modes for carrying out the invention]
[0009] The stator and rotating electric machine according to embodiments for implementing this disclosure will be described in detail below with reference to the drawings. In each drawing, the same reference numerals indicate the same or corresponding parts.
[0010] Embodiment 1. Figure 1 is a cross-sectional view of a rotating electric machine according to Embodiment 1. Figure 1 is a cross-sectional view of a plane parallel to the axis of rotation. As shown in Figure 1, the rotating electric machine 100 according to this embodiment has a cylindrical first housing 11 and a second housing 12 having a bottom, a stator 20 that is sandwiched and fixed in the axial direction between the first housing 11 and the second housing 12, and a rotor 30 that is arranged with a gap in the axial direction between the stator 20.
[0011] The stator 20 includes a plurality of stator cores 21 made of magnetic material, a plurality of coils 22 wound around the stator cores 21, a junction plate 23 for distributing current to the plurality of coils 22, and a stator case 24 made of non-magnetic material. The stator cores 21, coils 22, and junction plate 23 are electrically insulated from each other by bobbins (not shown) fixed to the stator cores 21. Three junction plates 23 are provided, one for each of the three phases, and each is electrically connected to a coil 22 of a different phase. Methods such as TIG (Tungsten Inert Gas) welding, resistance brazing, laser welding, and pressure welding can be used to electrically connect the junction plates 23 and the coils 22. The stator core 21 is composed of a first stator core 211 and a second stator core 212, which will be described later. The stator case 24 is composed of a first stator case 241 and a second stator case 242, which will be described later.
[0012] The rotor 30 has an annular yoke 31 made of a steel plate that easily conducts magnetic flux, and permanent magnets 32 arranged in a circumferential direction on the surface of the yoke 31. A rotating shaft 40 is fastened to the center of the rotor 30. In this embodiment, the rotating electric machine 100 has two rotors 30 facing each other on both sides of the stator 20 with a gap in between in the axial direction. The rotating shaft 40 is rotatably supported by the first housing 11 and the second housing 12 via bearings 50. The rotor 30 rotates relative to the stator 20 around the rotating shaft 40. Here, the direction parallel to the rotating shaft 40 is called the axial direction, the direction perpendicular to the rotating shaft 40 is called the radial direction, and the direction in which the rotor 30 rotates is called the circumferential direction. The inner diameter side is the direction approaching the rotating shaft 40 in the radial direction, and the outer diameter side is the direction moving away from the rotating shaft 40 in the radial direction.
[0013] The rotating electrical machine 100 of this embodiment is an axial-gap type rotating electrical machine, in which a stator 20 is disposed at the central portion in the axial direction, and a double-rotor structure in which two rotors 30 are disposed opposite to each other on both sides in the axial direction of the stator 20. This axial-gap type rotating electrical machine is characterized in that, compared with a radial-gap type rotating electrical machine in which the stator and the rotor are disposed opposite to each other in the radial direction, the area through which magnetic flux passes can be increased, so that the output density of the rotating electrical machine can be increased.
[0014] FIG. 2 is a top view of the stator according to this embodiment. FIG. 2 is a view of the stator 20 of this embodiment as seen from the side of the second housing 12. Further, FIG. 3 is a cross-sectional view of the stator at the position indicated by A-A in FIG. 2. The stator core 21 is formed of a compacted powder core made of powder such as iron. As shown in FIG. 3, the stator core 21 is composed of a second stator core 212 around which a coil 22 is wound and a first stator core 211.
[0015] The second stator core 212 is composed of a winding portion 212a around which a coil 22 is wound and a flange portion 212b having an area larger than the area of the winding portion 212a in order to increase the area through which magnetic flux passes at one end in the axial direction. That is, the area of the cross section of the flange portion 212b orthogonal to the axial direction is larger than the area of the cross section of the winding portion 212a orthogonal to the axial direction. The first stator core 211 is disposed at the end in the axial direction opposite to the flange portion 212b of the second stator core 212. The area of the first stator core 211 is the same as the area of the flange portion 212b of the second stator core 212. Therefore, it can be said that this first stator core 211 is one of the flange portions provided at both ends in the axial direction of the winding portion 212a. Although the first stator core 211 does not have a winding portion, a configuration in which a part of the winding portion 212a of the second stator core 212 is distributed to the first stator core 211 may be adopted. Further, the area of the first stator core 211 does not necessarily have to be the same as the area of the flange portion 212b of the second stator core 212. Furthermore, the second stator core 212 may be one in which the individually manufactured winding portion 212a and the flange portion 212b are integrated in advance using means such as adhesion.
[0016] The material of the stator case 24 is a non-magnetic material such as aluminum or resin. The stator case 24 is composed of an annular first stator case 241 and a cylindrical second stator case 242. A through hole 25 for flowing a coolant is formed in the central portion of the second stator case 242. The second stator case 242 has a cylindrical portion and a bottom portion, and the cylindrical portion is fastened to the outer diameter portion of the bottom portion. In the present embodiment, the cylindrical portion and the bottom portion are integrally formed, but the cylindrical portion and the bottom portion may be separate parts.
[0017] FIG. 4 is an exploded view of the stator according to the present embodiment. As shown in FIG. 4, in the stator of the present embodiment, 18 second stator cores 212 are arranged side by side in an annular shape. The second stator core 212 is arranged with the flange portion 212b downward and the winding portion 212a upward. The first stator case 241 is arranged on the flange portion 212b of the second stator core 212. The first stator case 241 has a disc shape, and a plurality of through holes 241a through which the winding portions 212a of the second stator cores 212 pass are formed.
[0018] A plurality of coils 22 are arranged on the first stator case 241. The 18 coils 22 are arranged side by side in an annular shape. The axial length of the coil 22 is shorter than the axial length of the winding portion 212a of the second stator core. Further above that, the second stator case 242 is arranged. The second stator case 242 has a cylindrical portion and a bottom portion, and a plurality of through holes 242a through which the winding portions 212a of the second stator cores 212 respectively pass are formed in the bottom portion. The first stator core 211 is arranged on the second stator case 242.
[0019] FIGS. 5 to 7 are diagrams for explaining the assembling procedure of the stator of the present embodiment. First, 18 second stator cores 212 are arranged in a circumferential direction. A positioning jig or similar device can be used to accurately arrange the second stator cores 212 in a circumferential direction. Next, adhesive is applied to the surface of the flange portion 212b of the second stator core 212 that contacts the first stator case 241. Then, the winding portion 212a of the second stator core 212 is passed through the through-hole 241a of the first stator case 241, fastening the first stator case 241 and the flange portion 212b of the second stator core 212. Figure 5 shows the state in which the first stator case 241 and the flange portion 212b of the second stator core 212 are fastened. Note that the adhesive may also be applied to the first stator case 241 instead of the flange portion 212b of the second stator core 212. Alternatively, it may be applied to the side surface of the through-hole 241a of the first stator case 241, or to the side surface of the winding portion 212a of the second stator core 212.
[0020] Next, an insulating bobbin (not shown) is placed on the side of the winding section 212a of the second stator core 212, and then the coil 22 is placed outside the winding section 212a as shown in Figure 6. The coil 22 can be made by bending a flat wire in advance using an edgewise process, for example, with a winding frame shaped to match the shape of the winding section 212a. Since the coil 22 is not connected to other coils 22 when it is placed outside the winding section 212a, the terminal wires of the coils 22 are connected to each other after the coil 22 is placed outside the winding section 212a. Note that, as shown in Figure 6, the axial length of the coil 22 is shorter than the axial length of the winding section 212a of the second stator core, so the winding section 212a protrudes above the coil 22.
[0021] Next, the first stator core 211 is bonded to the second stator case 242 with adhesive beforehand. Then, the winding portion 212a, which protrudes above the coil 22, is passed through the through hole 242a of the second stator case 242, and the second stator case 242 to which the first stator core 211 is bonded is fastened to the first stator case 241. At this time, adhesive is applied in advance to at least one of the surfaces on which the first stator case 241 and the second stator case 242 come into contact. Adhesive is also applied to the upper surface of the winding portion 212a, which is the surface on which the first stator core 211 and the second stator core 212 come into contact, thereby fastening the first stator core 211 and the second stator core 212. Figure 7 shows the state in which the first stator case 241 and the second stator case 242 are fastened together. In this way, the stator of this embodiment is completed.
[0022] In the stator assembly method of this embodiment, the terminal wires of the coil 22 are connected before assembling the second stator case 242 having a cylindrical portion and a bottom portion. As a result, the working space on the inner and outer diameter sides of the coil 22 is wide, improving the workability of connecting the terminal wires of the coil 22.
[0023] In a stator configured in this way, the flange portion 212b of the second stator core 212 is exposed at one axial end of the stator, and the first stator core 211 is exposed at the other end. As a result, in a rotating electric machine using this stator, the gap between the stator core and the rotor can be narrowed. Therefore, the torque characteristics of a rotating electric machine equipped with this stator can be improved.
[0024] Furthermore, since the space in which the coil 22 is located, surrounded by the stator core 21 and the stator case 24, is sealed with adhesive, coolant can be flowed through the through-hole 25. As a result, the heat dissipation performance of the stator is improved. In particular, when the stator case 24 is made of aluminum, the distance between the coil 22 and the stator case 24 is short, and the edge portion 212b of the stator core 21 and the stator case 24 are in close contact, thus improving heat dissipation performance.
[0025] In this embodiment, the axial length of the coil is shorter than the axial length of the winding portion of the second stator core, but the axial length of the coil may be longer than the axial length of the winding portion of the second stator core. In that case, the first stator core 211 may have a winding portion. In other words, in this embodiment, the stator core may have a winding portion around which the coil is wound, and flange portions with a larger cross-sectional area than the winding portion at both axial ends of the winding portion, and the stator core may be configured by being divided into two parts in the axial direction.
[0026] Furthermore, in the stator of this embodiment, the stator case is composed of a first annular stator case and a second stator case having a cylindrical portion and a bottom portion, but both the first and second stator cases may have a cylindrical portion and a bottom portion. In other words, in the stator of this embodiment, the stator case may have two annular bottom portions, each having a through hole through which the winding portions of a plurality of stator cores can pass, and a cylindrical portion that fastens the outer diameter portions of the two bottom portions in the axial direction, and the stator case may be composed of two axially divided portions.
[0027] In other words, the stator of this embodiment has a stator core having a winding section around which a coil is wound, and flange sections at both axial ends of the winding section having a cross-sectional area larger than the cross-sectional area of the winding section, and the stator core is divided into two parts in the axial direction, and the stator case has two annular bottom sections having through holes through which the winding sections of the multiple stator cores can pass, and a cylindrical section that fastens the outer diameter portions of the two bottom sections in the axial direction, and the stator case is divided into two parts in the axial direction, and the flange sections at both axial ends of the stator core are positioned axially outward from the two bottom sections of the stator case.
[0028] Furthermore, if the stator case 24 is made of an insulator such as resin, the stator case 24 acts as an insulator between the edges 212b of the first stator core 211 and the second stator core 212 and the coil 22, eliminating the need to place a bobbin in this position. Therefore, the axial length of the stator can be shortened.
[0029] Embodiment 2. Figure 8 is a perspective view of the stator according to Embodiment 2. Figure 8 shows only the second stator case of the stator of this embodiment. In the second stator case 242 of this embodiment, a slot portion 242b for housing the outer periphery of the first stator core 211 is formed on the outer periphery of the through hole 242a through which the winding portion of the second stator core passes. The depth of the slot portion 242b is less than or equal to the thickness of the first stator core 211. In addition, although not shown, a slot portion for housing the outer periphery of the flange portion of the second stator core is also formed on the outer periphery of the through hole of the first stator case. The depth of this slot portion is less than or equal to the thickness of the flange portion.
[0030] Figure 9 is a perspective view of the stator according to this embodiment. As shown in Figure 9, the first stator core 211 is housed in a slot portion 242b formed on the outer circumference of the through hole 242a of the second stator case 242 and joined to the second stator case 242. Although not shown, the flange portion of the second stator core is housed in a slot portion formed on the outer circumference of the through hole of the first stator case and joined to the first stator case.
[0031] This configuration facilitates the positioning of the stator case and the stator core. Furthermore, the increased contact area between the stator case and the stator core is expected to improve heat dissipation and adhesive strength.
[0032] Embodiment 3. Figure 10 is a cross-sectional view of the stator according to this third embodiment. Figure 10 is a cross-sectional view of the stator of this embodiment at the position indicated by AA in Figure 2 of the first embodiment. The structure of the stator of this embodiment is the same as the structure of the stator of the first embodiment. In the stator of this embodiment, the connecting wires 26 that connect the terminal wires of the coil 22 are arranged near the first stator case 241 in the space between the coil 22 and the second stator case 242.
[0033] In a stator configured in this way, the inner circumferential surface 242c of the second stator case 242 above the connecting wire 26 does not need to be machined with high precision to avoid contact with the connecting wire 26, thus reducing processing costs.
[0034] The various aspects of this disclosure are summarized below as an appendix. (Note 1) A stator comprising a plurality of stator cores made of a magnetic material, a plurality of coils wound around each of the plurality of stator cores, and a stator case made of a non-magnetic material that fixes the plurality of stator cores in an annular arrangement, The stator core has a winding section around which the coil is wound and flanges at both ends of the winding section in the axial direction, and the stator core is composed of a first stator core and a second stator core which are divided into two parts in the axial direction, and the area of the cross-section of the flanges perpendicular to the axial direction is larger than the area of the cross-section of the winding section perpendicular to the axial direction. The stator case has two annular bottoms, each having multiple through holes through which the winding portions of the multiple stator cores can pass, and a cylindrical portion that fastens the outer diameter portions of the two bottoms in the axial direction. The stator case is composed of a first stator case and a second stator case, which are divided into two parts in the axial direction. A stator characterized in that the flanges at both axial ends of the stator core are positioned axially outward from the two bottoms of the stator case. (Note 2) The stator according to Appendix 1, characterized in that the first stator core has only the flange portion, and the second stator core has both the winding portion and the flange portion. (Note 3) The stator according to Appendix 1 or 2, characterized in that the first stator case has only the bottom portion, and the second stator case has both the bottom portion and the cylindrical portion. (Note 4) The stator according to any one of the appendices 1 to 3, characterized in that the second stator core, the first stator case, the second stator case, and the first stator core are arranged in axial order. (Note 5) The stator according to any one of the appendices 1 to 4, characterized in that the first stator core and the second stator case are fastened together with an adhesive, and the second stator core and the first stator case are fastened together with an adhesive. (Note 6) The stator according to any one of the appendices 1 to 5, characterized in that the first stator core and the second stator core are fastened together with an adhesive. (Note 7) The stator according to any one of the appendices 1 to 6, characterized in that the first stator case and the second stator case are fastened together with an adhesive. (Note 8) The stator according to any one of the appendices 1 to 7, characterized in that a slot portion for housing the outer circumference of the flange portion is provided on the outer circumference of the through hole provided in the bottom portion on the axial side. (Note 9) A stator according to any one of the appendices 1 to 8, characterized in that a connecting wire for connecting the terminal wires of a plurality of coils is arranged between the stator case and the coils. (Note 10) A stator as described in any one of the appendices 1 to 9, A rotating electric machine characterized by having a stator and a rotor arranged with a gap in the axial direction. (Note 11) A method for manufacturing a stator as described in any one of the appendices 1 to 9, A step of arranging a plurality of the aforementioned second stator cores in a ring shape, The process of fastening the first stator case to the flange portion of the second stator core by passing the winding portions of the multiple second stator cores through the multiple through holes provided in the first stator case, A step of winding a plurality of coils around the winding portion of a plurality of second stator cores, The process of fastening the second stator case to the first stator case by passing the winding portions of the multiple second stator cores through the multiple through holes provided in the second stator case, A method for manufacturing a stator, characterized by comprising the step of fastening the first stator core to the winding portion of the second stator core.
[0035] While this disclosure describes various exemplary embodiments and examples, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment, but are applicable to the embodiments individually or in various combinations. Accordingly, countless variations not illustrated are conceivable within the scope of the art disclosed in this specification. These include, for example, modifying, adding or omitting at least one component, or even extracting at least one component and combining it with components of other embodiments. [Explanation of Symbols]
[0036] 11 First housing, 12 Second housing, 20 Stator, 21 Stator core, 22 Coil, 23 Connection plate, 24 Stator case, 25 Through hole, 26 Connecting wire, 30 Rotor, 31 Yoke, 32 Permanent magnet, 40 Rotating shaft, 50 Bearing, 100 Rotating electric machine, 211 First stator core, 212 Second stator core, 212a Winding section, 212b Flange section, 241 First stator case, 241a Through hole, 242 Second stator case, 242a Through hole, 242b Slot section, 242c Inner surface.
Claims
1. A stator comprising a plurality of stator cores made of a magnetic material, a plurality of coils wound around each of the plurality of stator cores, and a stator case made of a non-magnetic material that fixes the plurality of stator cores in an annular arrangement, The stator core has a winding portion around which the coil is wound and flange portions at both ends of the winding portion in the axial direction, and the stator core is composed of a first stator core and a second stator core which are divided into two parts in the axial direction, and the area of the cross-section of the flange portion perpendicular to the axial direction is larger than the area of the cross-section of the winding portion perpendicular to the axial direction. The stator case has two annular bottoms, each having multiple through holes through which the winding portions of the multiple stator cores can pass, and a cylindrical portion that fastens the outer diameter portions of the two bottoms in the axial direction. The stator case is composed of a first stator case and a second stator case, which are divided into two parts in the axial direction. A stator characterized in that the flanges at both axial ends of the stator core are positioned axially outward from the two bottoms of the stator case.
2. The stator according to claim 1, characterized in that the first stator core has only the flange portion, and the second stator core has both the winding portion and the flange portion.
3. The stator according to claim 1 or 2, characterized in that the first stator case has only the bottom portion, and the second stator case has both the bottom portion and the cylindrical portion.
4. The stator according to claim 1 or 2, characterized in that the second stator core, the first stator case, the second stator case, and the first stator core are arranged in axial order.
5. The stator according to claim 1 or 2, characterized in that the first stator core and the second stator case are fastened together with an adhesive, and the second stator core and the first stator case are fastened together with an adhesive.
6. The stator according to claim 1 or 2, characterized in that the first stator core and the second stator core are fastened together with an adhesive.
7. The stator according to claim 1 or 2, characterized in that the first stator case and the second stator case are fastened together with an adhesive.
8. The stator according to claim 1 or 2, characterized in that a slot portion for housing the outer circumference of the flange portion is provided on the outer circumference of the through hole provided in the bottom portion on the axial side.
9. The stator according to claim 1 or 2, characterized in that a connecting wire for connecting the terminal wires of a plurality of coils is arranged between the stator case and the coils.
10. A stator according to claim 1 or 2, A rotating electric machine characterized by having a stator and a rotor arranged with a gap in the axial direction.
11. A method for manufacturing a stator according to claim 1 or 2, A step of arranging a plurality of the second stator cores in a ring shape, The process of fastening the first stator case to the flange portion of the second stator core by passing the winding portions of the multiple second stator cores through the multiple through holes provided in the first stator case, A step of winding a plurality of coils around the winding portion of a plurality of second stator cores, The process of fastening the second stator case to the first stator case by passing the winding portions of the multiple second stator cores through the multiple through holes provided in the second stator case, A method for manufacturing a stator, characterized by comprising the step of fastening the first stator core to the winding portion of the second stator core.