Stator core, rotary motor and pressure fixture

Abstract

A stator core is provided, characterized in that: the stator core (30) comprises a plurality of stacked electromagnet plates (40); and a connecting portion (100) respectively disposed between adjacent electromagnet plates (40) in the stacking direction, wherein each electromagnet plate (40) comprises: an annular core back (41); a plurality of teeth (42) protruding radially from the core back (41) at intervals in the circumferential direction; and a connecting portion (43) connecting the front ends of adjacent teeth (42) to each other, wherein the connecting portion (100) comprises a first connecting portion (110) surrounding the space formed by the core back (41), the adjacent teeth (42) and the connecting portion (43) of the plurality of electromagnet plates (40).

Description

[Technical Field]

[0001] Field of the Invention This invention relates to a stator core, a rotary electric motor, and a pressure fixture. Priority is claimed under Japanese Patent Application No. 2024-124581 filed in Japan on July 31, 2024, the contents of which are incorporated herein by reference. [Previous Technology]

[0002] Background of the Invention In the process of automobile electrification, motors used in electric vehicles are expected to be small and have high output. Furthermore, thermal management of motors has become an important issue. To address this issue, cooling technologies such as direct oil cooling inside the motor have been adopted in recent years. As one method of cooling the inside of the motor, the following technology has been explored: forming a sealed structure for each slot of the stator core and allowing cooling medium to flow from the outside, thereby directly cooling the heat generated in the coil windings. For example, in Patent Document 1, in order to cool the windings inside the slots, a gap is provided on the outer diameter side of the windings close to the inner diameter side of the slot to ensure the path of the cooling medium, i.e., air. Prior Art Documents Patent Documents

[0003] Patent Document 1: Japanese Patent Application Publication No. 2014-128041 [Summary of the Invention]

[0004] Summary of the Invention Problems to be Solved by the Invention However, if cooling medium leaks out of the slot from the gaps between the layers of electromagnetic steel sheets laminated to form the stator core, there is a concern that the cooling medium may act as a resistance to the rotational force of the motor. Furthermore, especially when the cooling medium is liquid, if cooling medium leaks, it is necessary to replenish the leaked amount, requiring a structure or device for recovering the leaked cooling medium, thus increasing costs. On the other hand, if additional components are required to make the slot a sealed structure as a solution to cooling medium leakage, there is a concern that the occupancy rate of the coil windings may decrease. Therefore, the inventors of this invention have explored a sealed structure for the stator core that minimizes the need for additional components.

[0005] This invention was made in view of the above, and its object is to provide a stator core that can prevent the cooling medium flowing in the slot from leaking from the stator core. Means for solving the problem

[0006] (1) A stator core of one embodiment of the present invention comprises: a plurality of laminated electromagnetic steel plates; and a bonding portion disposed between adjacent electromagnetic steel plates in the laminated direction, wherein each electromagnetic steel plate comprises: an annular core back; a plurality of teeth protruding radially from the core back at intervals in the circumferential direction; and a connecting portion connecting the front ends of adjacent teeth to each other, wherein the bonding portion comprises a first bonding portion surrounding the space formed by the core back, the adjacent teeth and the connecting portion of the plurality of electromagnetic steel plates.

[0007] (2) In the stator core described in (1) above, it may also be: The first connecting part has: a peripheral connecting part, which is respectively provided on the aforementioned adjacent teeth; an inner connecting part, which is provided on the aforementioned connecting part and connects the radial inner sides of the aforementioned peripheral connecting parts of the aforementioned adjacent teeth to each other; and an outer connecting part, which is provided on the aforementioned core back and connects the radial outer sides of the aforementioned peripheral connecting parts of the aforementioned adjacent teeth to each other. (3) In the stator core described in (2) above, it may also be: The aforementioned peripheral connecting part is provided on the end of the aforementioned adjacent teeth that is closest to the aforementioned space; the aforementioned inner connecting part is provided at least on the radial outer end of the aforementioned connecting part; and the aforementioned outer connecting part is provided on the radial inner end of the aforementioned core back. (4) In the stator core described in (2) or (3) above, the compressive stress remaining in the region where the inner connecting portion is provided in the aforementioned connecting portion is greater than at least one of the compressive stress remaining in the region where the peripheral connecting portion is provided in the aforementioned tooth portion or the region where the outer connecting portion is provided in the aforementioned core back. (5) In the stator core described in (1) above, the first connecting portion may have: an inner ring connecting portion, which is provided in a ring shape covering the front end of the aforementioned plurality of teeth portions and the plurality of aforementioned connecting portions; and an outer ring connecting portion, which is provided in a ring shape covering the aforementioned core back. (6) In the stator core described in (5) above, the compressive stress remaining in the region where the inner ring connecting portion is provided in the aforementioned connecting portion is greater than at least one of the compressive stress remaining in the region where the inner ring connecting portion is provided in the front end of the aforementioned tooth portion or the region where the outer ring connecting portion is provided in the aforementioned core back. (7) In any of the stator cores described in (1) to (6) above, the aforementioned connection portion may further include a second connection portion disposed at a position different from the aforementioned first connection portion. (8) In the stator core described in (7) above, the aforementioned first connection portion may be solidified by a first adhesive with a bonding strength corresponding to the pressure during application and bonding, and the compressive stress remaining in the area of ​​the aforementioned connection portion where the aforementioned first connection portion is disposed is greater than the compressive stress remaining in the area of ​​the aforementioned electromagnet plate where the aforementioned second connection portion is disposed. (9) In the stator core described in (7) or (8) above, the aforementioned second connection portion may be disposed in all portions between the aforementioned electromagnet plates that do not have the aforementioned first connection portion.

[0008] (10) A rotating electric motor of the present invention comprises the stator core described in any one of (1) to (9) above.

[0009] (11) A pressure fixture of the present invention is characterized in that it is used in the manufacture of a stator core, wherein the stator core comprises a plurality of laminated electromagnetic steel plates and connecting portions respectively disposed between adjacent electromagnetic steel plates in the laminated direction; the stator core comprises a plurality of teeth and connecting portions connecting adjacent teeth; the pressure fixture comprises a member having a concave-convex surface on the pressing surface, wherein the pressing surface of the member is protruding at least at the position corresponding to the connecting portion. Effects of the Invention

[0010] According to the stator core of the present invention, leakage of the cooling medium flowing in the slot from the stator core can be prevented.

Implementation Method

[0012] The following description, which illustrates embodiments of the invention, is not limited to the examples described below. While specific values ​​or materials may be shown in the following description, other values ​​or materials may also be applied as long as the effects of the invention are achieved. Furthermore, the constituent elements of the following embodiments can be combined with each other.

[0013] Figure 1 is a schematic diagram illustrating a rotary electric machine 1 comprising a stator 10 and a rotor 20. Furthermore, in Figure 1, since the illustration is based on the scope required for explanation, other components of the rotary electric machine 1 are omitted. Also, coils and the like of the stator 10, permanent magnets or magnet insertion holes, gaps, and rotating shafts of the rotor 20 are omitted. Figure 1 is a cross-sectional view of the stator 10 and rotor 20 of the rotary electric machine 1 viewed from the lamination direction (hereinafter also referred to as the lamination direction) of the electromagnet plates 40, and is equivalent to a view after the rotary electric machine 1 has been cut perpendicularly to the lamination direction between adjacent electromagnet plates 40 in the lamination direction. In other words, Figure 1 is a cross-sectional view after the stator 10 has been cut along the radial direction D, for example, between adjacent electromagnet plates 40. Hereinafter, the radial direction D is the direction orthogonal to the central axis C of the stator 10. The circumferential direction R refers to the direction around the central axis C of the stator 10.

[0014] As shown in Figure 1, in the rotary electric machine 1, the stator 10 and the rotor 20 are arranged with the same central axis C. Generally, the stator 10 and the rotor 20 are constructed by laminating a plurality of electromagnetic steel plates in their thickness direction. Adjacent electromagnetic steel plates in the lamination direction constituting the stator 10 and the rotor 20 are fixed to each other by adhesive, bonding, or combination. Furthermore, the stator 10 has a stator core 30.

[0015] First, the stator core 30 of this embodiment will be described using FIG1. ​​As shown in FIG1, the stator core 30 of this embodiment includes: a plurality of laminated electromagnet plates 40, and a bonding portion 100 (first bonding portion 110) respectively disposed between adjacent electromagnet plates 40 in the lamination direction. Each electromagnet plate 40 includes an annular (circular in FIG1) core back 41, a plurality of teeth 42 that protrude from the core back 41 in the radial direction D at intervals in the circumferential direction R, and a connecting portion 43 that connects the front ends of adjacent teeth 42 to each other.

[0016] In this embodiment, the tooth 42 protrudes from the core back 41 toward the radially inward direction. That is, when viewed from the lamination direction (see Figure 1), if the outermost edge 41e of the radial direction D of the annular core back 41 is defined as the outer edge 41e, and the innermost edge 41i is defined as the inner edge 41i, each of the plurality of teeth 42 extends to protrude from the inner edge 41i of the annular core back 41 toward the central axis C. The innermost end of the tooth 42 in the radial direction D is the front end of the tooth 42. Furthermore, when viewed from the lamination direction, the outer edge 41e of the core back 41 coincides with the side surface of the electromagnetic steel plate 40 (the surface whose length in the lamination direction becomes the plate thickness). Also, the front end of the tooth 42 is the portion that includes the front end of the tooth 42, and the connecting portion 43 can also be connected to the portion of the front end of the tooth 42 other than the front end (the portion closer to the radially outer side than the front end). The details of the next part 100 will be described later. The next part 100 includes at least the first next part 110 and may also include the second next part 120.

[0017] Then, by stacking a plurality of electromagnetic steel plates 40 constituting the stator core 30 described above, the gaps formed on the inner side of each electromagnetic steel plate 40 by two adjacent teeth 42, the core back 41 (inner edge 41i), and the connecting portion 43 are connected in the stacking direction, thereby forming a space (hereinafter referred to as slot 44) penetrating the stator core 30 in the stacking direction. A coil 50 can be accommodated inside this slot 44 (see Figures 2 and 3 described later). The space inside the slot 44 where there is no coil 50 is connected in the stacking direction to connect the outer sides of the two ends of the slot 44 in the radial direction D, thus forming a cooling medium, such as cooling water, oil, or gas, that can flow through it. Furthermore, the teeth 42 can also protrude from the core back (also called yoke) toward the radial direction outward. A stator core with such a shape can be used in an external rotor type rotary motor.

[0018] In the embodiment shown in FIG1, the width (length of radial direction D) of the connecting portion 43 is generally fixed in the circumferential direction (the same applies to FIG2 to FIG4 described later). However, the specific shape of the connecting portion 43 can be arbitrary as long as the front ends of adjacent teeth 42 are connected to each other. For example, the connecting portion 43 may also have a portion with a width different from other positions. For example, when viewed from the stacking direction, the outer edge of the radial direction D of the connecting portion 43 may be formed by one or more straight lines or arcs.

[0019] Furthermore, in the stator core 30 of this embodiment, although all of the laminated electromagnetic steel plates 40 have the aforementioned connecting portion 43, only a portion of the laminated electromagnetic steel plates 40 may have the aforementioned connecting portion 43. In this case, in electromagnetic steel plates (not shown) that do not have the connecting portion 43, the gaps may be filled with a resin or the same material as the first bonding portion 110, instead of the material without the connecting portion 43, to connect the front ends of adjacent teeth. It can also be configured such that the bonding portion is formed to the same thickness as the electromagnetic steel plate, thereby surrounding the groove 44 with the bonding portion and preventing leakage of cooling medium from the inside of the groove 44. Furthermore, the thickness of each electromagnetic steel plate 40 forming the stator core 30 can be appropriately determined by considering the magnetic characteristic improvement effect such as iron loss improvement effect, or manufacturing cost, and pressing and punching workability.

[0020] Next, the aforementioned bonding portion 100 will be described in detail using Figures 2 to 4. Figures 2 and 3 are enlarged views corresponding to the area near the groove 44 in Figure 1, and are used to explain the first bonding portion 110 of one embodiment of the present invention. Also, Figure 4 is a cross-sectional view of the stator 10, which is different from the embodiment of Figures 1 to 3, viewed from the lamination direction in the same manner as Figure 1.

[0021] The bonding portion 100 is provided on the surface of the laminated electromagnet plates 40 facing each other, i.e., the surface of the electromagnet plates 40 (the plate surface facing the lamination direction). The bonding portion 100 is the adhesive applied between adjacent electromagnet plates 40 that has solidified (hardened). Two adjacent electromagnet plates 40 in the stator core 30 can also be bonded to each other by the bonding portion 100. That is, the bonding portion 100 may not bond adjacent electromagnet plates 40 to each other in at least a portion. In other words, the bonding portion 100 may also include: a first bonding portion 110 that does not contribute to the fixation formed by bonding the electromagnet plates 40 to each other, and a bonding portion that contributes to the fixation formed by bonding the electromagnet plates 40 to each other (such as a second bonding portion 120, etc., described later). In the case where the bonding portion 100 does not bond all adjacent electromagnet plates 40 to each other, the electromagnet plates 40 may be fixed to each other by other fixing means such as convergence. Examples of adhesives used for bonding the adhesive portion 100 include thermosetting adhesives formed by polymerization, acrylic adhesives (i.e., room temperature curing adhesives), anaerobic adhesives, instant adhesives, and acrylic adhesives containing elastomers.

[0022] Alternatively, at least a portion of the bonding portion 100 may also be formed by an adhesive coating applied to the entire surface of the electromagnetic steel plate 40. The adhesive coating is, for example, an adhesive that solidifies by heat treatment. In this case, two adjacent electromagnetic steel plates 40 in the stator core 30 are bonded to each other by the adhesive coating. The bonding of the electromagnetic steel plates 40 formed by the adhesive coating is performed by a pressure fixture as described later. Furthermore, the adhesive may be applied from an insulating film applied to the surface of the electromagnetic steel plate 40, or it may be applied to the surface of the electromagnetic steel plate 40 without an insulating film.

[0023] Furthermore, as shown in Figures 2 and 3, the connecting portion 100 includes a first connecting portion 110, which surrounds the groove 44 provided by the stator core 30. More specifically, as shown in Figures 2 and 3, the first connecting portion 110 may also have a peripheral connecting portion 111, an inner connecting portion 112, and an outer connecting portion 113. The peripheral connecting portions 111 are respectively provided on two adjacent teeth 42 (e.g., 42A and 42B). The inner connecting portion 112 is provided on the connecting portion 43 and connects the radially inner sides of the peripheral connecting portions 111 of each of the adjacent teeth 42 to each other. The outer connecting portion 113 is provided on the core back 41 and connects the radially outer sides of the peripheral connecting portions 111 of each of the adjacent teeth 42 to each other. The peripheral connecting portions 111 may also be provided along the radial direction D in each of the two adjacent teeth 42.

[0024] That is, when viewed from the stacking direction, in each slot 44 of the stator core 30, the first connecting portion 110 is formed by two peripheral connecting portions 111, an inner connecting portion 112, and an outer connecting portion 113 facing each other and sandwiching the slot 44, thus surrounding the corresponding slot 44. Furthermore, when viewed from the stacking direction, each of the first connecting portions 110 is formed continuously without interruption.

[0025] In the embodiment shown in FIG2, the peripheral connecting portion 111 is provided at the end closest to the groove 44 of each of the adjacent teeth 42 and away from the edge of each tooth 42 (groove peripheral edge 44a). That is, the peripheral connecting portion 111 is not disposed on the entire tooth 42, and is provided at a distance from the edge in the circumferential end portion. Similarly, the outer connecting portion 113 is provided at the radially inner end of the core back 41 (not the entire core back 41 but the end portion) and away from the groove outer edge 44c. Furthermore, a portion of the inner edge 41i is repeated with the groove outer edge 44c. The inner connecting portion 112 is provided at the radially outer end of the connecting portion 43 and away from the radially outer edge (groove inner edge 44b). In Figure 2, although the separation distances of each part constituting the first connection portion 110, measured from the edge of the groove 44 (groove periphery 44a, groove inner 44b, and groove outer 44c), are generally the same, they may also have portions or positions that have different separation distances from others.

[0026] According to the above configuration, the cooling medium leaking from the groove 44 to the electromagnetic steel plate 40 can be kept near the groove 44 by means of the first connecting part 110 surrounding the groove 44.

[0027] In the embodiment shown in FIG3, the peripheral bonding portion 111 is provided at the end closest to the groove 44 of each of the adjacent teeth 42 and overlaps with the edge (groove peripheral edge 44a) of each tooth 42. That is, the peripheral bonding portion 111 is not disposed on the entire tooth 42, but is provided at the end in the circumferential direction, and when viewed from the stacking direction, the end of the peripheral bonding portion 111 coincides with the side of the forming groove 44 of the electromagnetic steel plate 40. Similarly, the outer bonding portion 113 is provided at the end (not the entire core back 41 but the end portion) of the inner radial direction of the core back 41 and overlaps with the inner edge 41i (groove outer edge 44c) of the core back 41. The inner bonding portion 112 is provided at the end of the outer radial direction of the connecting portion 43 and overlaps with the outer radial edge (groove inner edge 44b). Furthermore, the first connecting portion 110 may reach the inner wall of the groove 44 in at least a portion of each of the portions constituting the first connecting portion 110.

[0028] According to the above configuration, by providing the first connecting portion 110 surrounding the groove 44 to the edge of the groove 44, not only can leakage of the cooling medium to the outside of the groove 44 be prevented, but leakage of the cooling medium to the adjacent electromagnet plates 40 (the surface of the electromagnet plates 40) can also be prevented. Furthermore, if we consider the case where the widths of the portions forming the first connecting portion 110 in Figures 2 and 3 are all the same, since the case in Figure 3 is such that the first connecting portion 110 is located further away from the area where the magnetic flux mainly flows during operation (the area at the center of the circumference of the tooth portion 42), the first connecting portion 110 becomes less likely to obstruct the flow of magnetic flux, and the degradation of motor characteristics can be expected to be suppressed. Furthermore, according to the above configuration, leakage of the cooling medium can be prevented without the need for additional components. Therefore, space is not required for additional components, and the opening area of ​​the groove 44 can be ensured. Furthermore, since no additional components are required in the above configuration, it is also advantageous from the viewpoint of manufacturing efficiency.

[0029] Furthermore, in Figures 2 and 3, the inner bonding portion 112 may also be provided on the entire connecting portion 43. In Figure 3, the first bonding portion 110 is provided to the edge (side) of the forming groove 44 of the electromagnetic steel plate 40 at all positions when viewed from the lamination direction, but it may not be provided to the edge at at least one of the two peripheral bonding portions 111, the inner bonding portion 112 and the outer bonding portion 113, or at least one of the first bonding portions 110.

[0030] Furthermore, the width of the first attachment portion 110, including the width of the peripheral attachment portion 111, the width of the inner attachment portion 112, and the width of the outer attachment portion 113, is not particularly limited, as long as it can be appropriately set from the viewpoint of preventing leakage of the cooling medium. Also, from the viewpoint of iron loss degradation, the width of the attachment portion can be appropriately set considering both leakage prevention and iron loss degradation. Here, the width of the attachment portion refers to its length in the direction perpendicular to the length direction (extension direction) of the attachment portion when viewed from the lamination direction.

[0031] As explained above using Figures 2-3 (and Figure 1 as well), the first connecting portion 110 is composed of a peripheral connecting portion 111, an inner connecting portion 112, and an outer connecting portion 113. Each slot 44 of the stator core 30 is surrounded without gap by a plurality of first connecting portions 110 and a plurality of electromagnetic steel plates 40 arranged alternately in the lamination direction. This prevents leakage of the cooling medium flowing within the slot 44 to the outside of the slot 44 (Figure 3) or keeps it near the slot 44 (Figure 2). Accordingly, leakage of the cooling medium from the stator core 30 to the outside can be prevented.

[0032] Alternatively, as shown in FIG4, the first connecting portion 110 may also have: an inner ring connecting portion 121, which covers the front ends of a plurality of teeth 42 forming the inner periphery of the annular stator core 30 and a plurality of connecting portions 43 continuously arranged in an annular shape; and an outer ring connecting portion 122, which is continuously arranged in an annular shape on the core back 41. The inner ring connecting portion 121 and the outer ring connecting portion 122 are each formed continuously without interruption. That is, when viewed from the lamination direction, the plurality of grooves 44 are surrounded by the inner ring connecting portion 121 and the outer ring connecting portion 122.

[0033] In the embodiment shown in FIG. 4, the outer ring connection portion 122 is formed in a circular (perfectly circular) shape in the central region of the annular core back 41. However, the present invention is not limited to this embodiment. For example, the outer ring connection portion 122 may also be formed in a region closer to the inner edge 41i or outer edge 41e of the core back 41 than the central region of the core back 41. The closer the outer ring connection portion 122 is to the inner edge 41i of the core back 41, the smaller the range of cooling medium leaking from the groove 44 to the electromagnet plate 40 can be. Since the outer ring connection portion 122 is closer to the outer edge 41e of the core back 41, the outer ring connection portion 122 is further away from the region where the magnetic flux mainly flows during the operation of the rotating motor (the region radially inward of the core back 41), so the deterioration of magnetic properties such as iron loss caused by the compressive stress (strain) imparted to the electromagnet plate 40 due to the solidification of the adhesive can be reduced. Furthermore, if compressive stress (elastic compressive stress) is applied to the steel plate, iron loss will increase, as has been documented in, for example, the literature by Yasumoto et al. (Nippon Steel Technical Report No. 378, pp. 51-54 (2003)).

[0034] Furthermore, in the embodiment shown in FIG4, although the inner ring connector 121 and the outer ring connector 122 each have an annular shape with a generally fixed width, at least one of them may include at least a portion of a straight line portion, a wavy portion, a curved portion with a curvature different from the others, or a portion with a width different from the others, or a portion may exist in the tooth portion 42, or a combination of these may be included. The width of the first connector 110 refers to the length in the direction perpendicular to the length direction (extension direction) of the connector when viewed from the lamination direction. The widths of the inner ring connector 121 and the outer ring connector 122 are arbitrary. Furthermore, each of the inner ring connector 121 and the outer ring connector 122 may be constructed by one or more annular connectors at intervals across the radial direction D. When the outer ring connector 122 includes a plurality of annular connectors, the outer ring connector 122 can also be formed by a plurality of annular connectors spaced apart in the radial direction D, for example, in at least a portion of the core back 41, such as the central region described above. The outer ring connector 122 can also be provided on the entire surface of the core back 41. Similarly, when the inner ring connector 121 includes a plurality of annular connectors, the inner ring connector 121 can also be formed by a plurality of annular connectors spaced apart in the radial direction D at the front end of the tooth 42 and in the connecting portion 43.

[0035] In this way, all the slots 44 of the stator core 30 can be surrounded by the first connection portion 110 having the inner ring connection portion 121 and the outer ring connection portion 122, thereby preventing the cooling medium from leaking from the stator core 30 to the outside.

[0036] The first connection portion 110 has been described above using Figures 2 to 4. As mentioned above, each slot 44 of the stator core 30 can be individually (see Figures 1 to 3) or entirely (see Figure 4) surrounded by the first connection portion 110. This prevents the cooling medium flowing in the slots 44 from leaking out of the area surrounded by the first connection portion 110 to the outside in the stator core 30. Thus, leakage of the cooling medium from the stator core 30 to the outside can be prevented. Furthermore, from the viewpoint of ensuring the flow of magnetic flux, it is preferable to configure each slot 44 to be surrounded by one first connection portion 110 as described above. However, from the viewpoint of simplifying the manufacturing process, it is also possible to configure one first connection portion 110 to surround a plurality of adjacent slots 44.

[0037] Next, we will explain aspects other than the configuration of the first bonding portion 110 described above. The first bonding portion 110 may also be solidified by a first adhesive with a bonding strength corresponding to the pressure applied during bonding. The bonding strength of this first adhesive changes depending on the pressure applied during bonding. For example, the higher the pressure during bonding, the higher the bonding strength after solidification. This first adhesive may also be applied to the entire surface between adjacent electromagnet plates 40, or at least around the grooves 44 (Figs. 2 and 3) or the area surrounding a plurality of grooves 44 (Fig. 4), etc., to at least a portion of the surface of the stator core 30, and a stronger pressure is applied only locally to the area that becomes the first bonding portion 110 to bond it, thereby forming the first bonding portion 110. When the first adhesive is applied to the entire surface, an adhesive coating may also be formed by the first adhesive. The adhesive used to form the bonding coating can also be a type of adhesive that hardens through heat treatment. Applying adhesive to the target area of ​​each piece of stator core cut from sheet by sheet is labor-intensive and prone to unevenness. By applying the adhesive as a coating (film), it is advantageous to suppress uneven application and easily achieve uniform build-up thickness. As a result, the bonding portion 100 includes the first bonding portion 110 and the other bonding portions. Examples of adhesives used as the first adhesive include, for instance, thermosetting adhesives formed by polymerization, acrylic adhesives (room temperature curing adhesives), anaerobic adhesives, instant adhesives, and acrylic adhesives containing elastomers.

[0038] According to the above configuration, by only locally and strongly bonding the regions forming the first bonding portion 110 in adjacent electromagnet plates 40, the adjacent electromagnet plates are bonded together by the first bonding portion 110, and the region forming the first bonding portion 110 is bonded more strongly than other regions (such as the region forming the second bonding portion 120, as described later). This allows the contribution of the first bonding portion 110 to the fixing force between the electromagnet plates 40 to be greater than in the case of setting a uniform bonding strength. Accordingly, even if the bonding strength of the bonding portion 100 other than the first bonding portion 110 is set weaker, or the area of ​​that portion is set smaller, the required fixing force for the stator core can still be ensured. Therefore, since the bonding strength in the area where the magnetic flux mainly flows during operation can be reduced by weakening the bonding strength in areas other than the first bonding portion 110, the effect of increased iron loss caused by the compressive stress imposed on the electromagnet steel plate 40 by the bonding portion 100 can be reduced. As a result, the degradation of the characteristics of the stator 10 as a whole can be suppressed, and the outflow (leakage) of the cooling medium from the inside of the tank 44 to the outside can be prevented.

[0039] Furthermore, the compressive stress (residual compressive stress) remaining in the region where the first bonding portion 110 is provided in the connecting portion 43 of the electromagnetic steel plate 40 may become greater than the compressive stress remaining in the region where the first bonding portion 110 is provided in the parts other than the connecting portion 43 of the electromagnetic steel plate 40.

[0040] The compressive stress remaining in the electromagnetic steel plate 40 can be measured, for example, by X-ray diffraction, as described in the Standard for X-ray Stress Measurement (2002) = Iron and Steel = (JSMS-SD-5-02), Japan Materials Society. When measuring the compressive stress remaining in the electromagnetic steel plate 40 using X-ray diffraction, the stator 10 is divided in the lamination direction using the joint 100 between the electromagnetic steel plates 40 as the boundary. There are no particular limitations on how the stator 10 is divided in the lamination direction; simply push a tool into the gap between the electromagnetic steel plates 40 (joint 100) and apply force from this tool to divide the stator 10 into two pieces. Alternatively, the joint 100 can be cut off to divide the stator 10 into two pieces. This process is repeated to expose the joint 100 between the electromagnetic steel plates 40. While the presence or absence of the adhesive portion 100 can be confirmed by visually inspecting the collected electromagnetic steel sheet 40, the compressive stress remaining on the electromagnetic steel sheet 40 is measured by preparing a sample suitable for the aforementioned X-ray diffraction method using the collected electromagnetic steel sheet 40. When using the X-ray diffraction method, since the adhesive portion 100 on the surface of the electromagnetic steel sheet 40 prevents X-rays from penetrating to the target depth of the electromagnetic steel sheet 40, it is desirable to remove the adhesive portion 100. On the other hand, when visually inspecting the coating state (shape, etc.) of the adhesive portion 100, it is preferable to leave traces of the adhesive portion 100.

[0041] Alternatively, for example, when the first connecting portion 110 shown in FIG2 and FIG3 is constructed of a peripheral connecting portion 111, an inner connecting portion 112 and an outer connecting portion 113, the compressive stress remaining in the area of ​​the connecting portion 43 where the inner connecting portion 112 is provided will become greater than at least one of the compressive stress remaining in the area of ​​the tooth portion 42 where the peripheral connecting portion 111 is provided, or in the area of ​​the core back 41 where the outer connecting portion 113 is provided.

[0042] Alternatively, when the first connecting portion 110 shown in FIG4 is constructed of an inner ring connecting portion 121 and an outer ring connecting portion 122, the compressive stress remaining in the area of ​​the connecting portion 43 where the inner ring connecting portion 121 is provided will become greater than the compressive stress remaining in the area of ​​the front end of the tooth portion 42 where the inner ring connecting portion 121 is provided or the area of ​​the core back 41 where the outer ring connecting portion 122 is provided, or both.

[0043] Since the connecting portion 43 connects the front ends of adjacent teeth 42, magnetic flux can flow in the connecting portion 43 during the operation of the rotary motor 1, resulting in poor performance of the rotary motor 1. Therefore, in this embodiment, taking advantage of the fact that the magnetic properties of the electromagnet plate 40 deteriorate due to the solidification of the adhesive, a higher pressure is applied to solidify the first adhesive, so that a stronger bonding strength (adhesive force) required for bonding and fixing can be achieved in the connecting portion 43. This can actively increase the iron loss of the connecting portion 43 and make it difficult for magnetic flux to flow in the connecting portion 43. Accordingly, the deterioration of motor characteristics caused by the flow of magnetic flux through the connecting portion 43 can be suppressed.

[0044] The distribution of residual compressive stress in the first bonding portion 110 can also be achieved by, for example, using two or more different types of adhesives and uniformly applying pressure to the surface of the electromagnetic steel sheets laminated when the electromagnetic steel sheets 40 are joined together. In this case, the adhesive that solidifies into the first bonding portion 110 can be called the first adhesive, and the adhesive that solidifies into the second bonding portion 120 can be called the second adhesive. Alternatively, the first adhesive described above can be used in the formation of the first bonding portion 110, and pressure can be applied by changing the pressure distribution during joining, thereby achieving the distribution of residual compressive stress. Here, when manufacturing the stator core 30, the electromagnetic steel sheets 40 coated with the adhesive that forms the bonding portion 100 are laminated, and the laminated electromagnetic steel sheets 40 are joined by pressure in the lamination direction. Pressurization is achieved, for example, by a pressurizing device that pressurizes the stator core 30, through a pressurizing fixture that pushes the stator core 30. The pressure distribution on the surface of the electromagnet plate 40 during contact can be adjusted by creating unevenness in this pressurizing fixture. For example, a pressurizing fixture that can apply locally higher pressure can also be used by making the portion corresponding to the connecting portion 43 in the first contact portion 110 protrude more in the direction of applying pressure than other portions. By using such a pressurizing fixture, the pressure distribution on the surface of the electromagnet plate 40 during contact can be arbitrarily set. An example of a pressurizing fixture will be described later.

[0045] Based on the above configuration, the bonding strength of the portion of the first bonding portion 110 corresponding to the connecting portion 43 can be intentionally set to be greater than the bonding strength of the portion corresponding to the core back 41 or the tooth portion 42. In this way, since the iron loss of the connecting portion 43 can be increased, making it difficult for magnetic flux to flow in the connecting portion 43, the deterioration of motor characteristics can be suppressed.

[0046] Furthermore, the plurality of electromagnet plates 40 constituting the stator core 30, as shown in Figures 1 to 4, can also be fixed by a bonding portion 100 including the first bonding portion 110 described above and a second bonding portion 120 disposed at a different position from the first bonding portion 110. In this case, the second bonding portion 120 can be disposed on at least a portion of the surface of each electromagnet plate 40 in the area where the first bonding portion 110 is not disposed, or it can be disposed on all of them. In particular, when the entire surface of the electromagnet plate 40 is covered by the bonding portion 100 including the first bonding portion 110 and the second bonding portion 120, the bonding portion 100 can also be formed by the first adhesive solidifying under the pressure distribution described above.

[0047] When adjacent electromagnetic steel plates 40 in the lamination direction are covered by the bonding portion 100 via the first bonding portion 110 and the second bonding portion 120, the compressive stress remaining in the region of the electromagnetic steel plate 40 where the first bonding portion 110 is provided may be greater than the compressive stress remaining in the region of the electromagnetic steel plate 40 where the second bonding portion 120 is provided. This latter distribution of residual compressive stress can be formed, for example, by using two or more different types of adhesives and uniformly applying pressure to the surface of the laminated electromagnetic steel plates. Alternatively, the adhesives forming the first bonding portion 110 and the second bonding portion 120 may be of the same type in the electromagnetic steel plate 40, and the aforementioned first adhesive and pressure fixture may be used in the formation of the first bonding portion 110 and the second bonding portion 120. Alternatively, it can be that in the region of the electromagnetic steel plate 40 where the first connecting portion 110 is provided, the compressive stress remaining in the region where the connecting portion 43 is provided is greater than the compressive stress remaining in the region of the electromagnetic steel plate 40 where the second connecting portion 120 is provided.

[0048] For example, in the examples of Figures 1 to 4, when the entire surface portion of the electromagnet plate 40 without the first bonding portion 110 is designated as the second bonding portion 120, the first adhesive is applied between all adjacent electromagnet plates. A pressure fixture, with its uneven surface configured such that the area corresponding to the first bonding portion 110 is a protrusion and the area corresponding to the second bonding portion 120 is a recess, applies pressure to solidify the first adhesive. In this way, a bonding portion 100 is formed in Figures 1 to 4 where the entire area without the first bonding portion 110 becomes the second bonding portion 120.

[0049] According to the above configuration, the stator core 30 is fixed by a connection portion 100 including a first connection portion 110 and a second connection portion 120. This prevents the cooling medium flowing through the groove 44 from leaking to the outside of the stator core 30 and securely fixes the stator core 30. Furthermore, since the second connection portion 120 is provided only on the portion of the electromagnet plates 40 between each other that does not contain the first connection portion 110, the surfaces of the electromagnet plates 40 can be integrally connected by the first connection portion 110 and the second connection portion 120, thus further enhancing the prevention of cooling medium leakage and the fixing force of the stator core 30.

[0050] However, the present invention is not limited to the embodiments described above. The bonding portion 100 may also not include the second bonding portion 120, but only the first bonding portion 110. For example, the first bonding portion 110 may be formed only in the portion where the first bonding portion 110 is to be formed by applying the first adhesive described above and allowing it to solidify. Furthermore, the second bonding portion 120 may be changed to be fixed by other fixing means, thereby fixing the plurality of electromagnet plates 40 constituting the stator core 30. Other fixing means include joining, welding, etc.

[0051] (Pressure Fixture) Hereinafter, a pressure fixture 200 that can be used in the manufacture of the stator core 30 of the above embodiment will be described. Figure 5 is a schematic diagram showing an example of using the pressure fixture 200. The pressure fixture 200 is used when pressure must be applied to the bonding. For example, it is mainly used when a bonding coating (bonding film) is provided on the electromagnetic steel plate 40.

[0052] The pressure jig 200 is a jig used to press and fix at least a portion of the plurality of electromagnetic steel plates 40 constituting the stator core 30, which are stacked in a state of being sandwiched with adhesive (hereinafter referred to as core portion P), during the manufacturing of the stator core 30. As shown in FIG5, the pressure jig 200 includes a first member 210, the first member 210 having an uneven surface 211 for pressing the core portion P while making contact, etc. The core portion P is joined by applying pressure through the first member 210 by the pressing part 201 of the pressing device. The pressure can also be applied after heating the core portion P to a predetermined temperature.

[0053] More specifically, the pressing surface 211 of the first member 210 is more prominent in the stacking direction of the stator core 30 at the position (region) corresponding to the region forming the first attachment portion 110 than at the position (region) corresponding to the region forming the second attachment portion 120. That is, the position corresponding to the first attachment portion 110 is convex in the stacking direction of the stator core 30, and the position corresponding to the second attachment portion 120 is concave in the stacking direction of the stator core 30. In this way, the pressing surface 211 has: a first pressing portion 211A (convex portion), configured to press relatively strongly at the position corresponding to the first attachment portion 110; and a second pressing portion 211B (concave portion), configured to press relatively weakly at the position corresponding to the second attachment portion 120.

[0054] In summary, the pressure fixture 200 has an uneven pressing surface 211, so that the pressure applied to the desired area of ​​the core portion P during bonding becomes higher than that of other areas. The shape of the uneven pressing surface 211, viewed from the planar perspective of the stator core 30 in the stacking direction, is designed according to the shape or position of the first bonding portion 110. Thereby, the pressure applied during pressing becomes higher for the protruding areas than for the concave areas. Accordingly, when the adhesive used for bonding and fixing the stator core 30 is an adhesive of the type that can exert a bonding strength corresponding to the magnitude of the pressure applied during bonding, the first bonding portion 110 and the second bonding portion 120 can be formed by applying pressure to the core portion P at one time.

[0055] In the embodiment shown in FIG. 5, the pressure fixture 200 (first member 210) is a mold or the like that forms protrusions and concavities on a metal plate having a predetermined thickness in the thickness direction, and is a member with protrusions and concavities formed on a plate-shaped member. Furthermore, by pressing with the pressing part 201, the first pressing part 211A in the first member 210 presses a predetermined portion of the electromagnetic steel plate 40, and the second pressing part 211B presses an area other than the predetermined portion. The predetermined portion includes at least the position corresponding to the connecting part 43, but may also include the entire position corresponding to the first connecting part 110. By the pressing surface 211, the predetermined portion protrudes more than at least a portion of its surroundings, the predetermined portion corresponds to the protruding convex portion, and at least a portion of the surroundings of the convex portion corresponds to the concave portion.

[0056] Furthermore, the pressing surface 211 has a tapered portion 212 connecting the first pressing portion 211A and the second pressing portion 211B. That is, the first pressing portion 211A and the second pressing portion 211B are smoothly connected, thus forming a gradual change in applied pressure. As a configuration for gradually changing applied pressure, the tapered portion 212 may, for example, gradually tilt at a fixed ratio, or change in a quadratic curve manner.

[0057] Furthermore, in the embodiment shown in FIG5, the first member 210 is positioned above the core portion P with its pressing surface 211 facing downwards. Also, by placing the core portion P on the upper surface of the second member 220, which is already fixed below the core portion P, and while supporting the core portion P from below, the pressing part 201 of the pressing device presses the first member 210 in the direction of arrow F (downward direction of the lamination direction), thereby applying pressure to the core portion P for subsequent fixation.

[0058] However, the present invention is not limited to the embodiments described above. For example, the first member 210 may be disposed below and the second member 220 above. Also, in addition to the first member 210, the support surface of the core portion P in the second member 220 may also have irregularities to match the irregularities of the pressing surface 211 of the first member 210. Furthermore, the first pressing portion 211A and the second pressing portion 211B of the first member 210 may not have a tapered portion 212, or they may be connected, for example, by a stepped section.

[0059] Furthermore, Figure 5 is a simplified representation to facilitate understanding of the shape of the pressure fixture 200, and the actual dimensions of the pressure fixture 200 may differ. For example, in the arrow view of Figure 5 (side view of the stator core 30), the difference H (μm) between the unevenness of the pressing surface 211 is provided. The difference H can also be determined based on the relationship between the pressure conditions of the adhesive obtained in advance through experiments or calculations and the strength increase of the electromagnetic steel plate 40 formed by providing the first bonding part 110.

[0060] According to the pressure fixture 200 described above, a pressure distribution can be established on the surface of the electromagnetic steel plate 40 during a single pressurization by means of the unevenness formed on the pressing surface 211. Accordingly, during the bonding and fixing process, a higher pressure can be applied to the area of ​​the electromagnetic steel plate 40 where the first bonding portion 110 is to be formed than to the area where the second bonding portion 120 is to be formed by a single pressure application. As a result, since the first bonding portion 110 and the second bonding portion 120 can be formed efficiently, the manufacturing cost of the stator core 30 can be reduced.

[0061] (Rotating Electric Machine) The rotating electric machine of this embodiment has the stator core of the above-described embodiment. Because the rotating electric machine of this embodiment has the stator 10 described above, leakage of the cooling medium from the stator core 30 can be prevented, and there is no need for a structure or device to recover the leaked cooling medium. Furthermore, a rotating electric machine refers to a motor or generator. As a motor, there is no particular limitation; the type of motor can also be, for example, an IPM (Interior Permanent Magnet) motor, an IM (Induction Motor), or an EESM (Electrically Excited Synchronous Motor). Also, the rotating electric machine can be an external rotor type motor. Industrial Applicability

[0062] According to the stator core of the present invention, leakage of the cooling medium flowing in the slot from the stator core can be prevented. Furthermore, since the rotary electric machine of the present invention has the aforementioned stator, leakage of the cooling medium from the stator core can be prevented, and no structure or device for recovering leaked cooling medium is required. Moreover, by using the pressure fixture of the present invention, a connection having a first connection portion and a second connection portion can be efficiently formed. Therefore, the present invention is extremely useful industrially. [Simplified Explanation of the Diagram]

[0011] FIG1 is a diagram illustrating a rotary electric motor according to one embodiment of the present invention, and is a cross-sectional view of the stator and rotor of the rotary electric motor viewed from the direction of the stacking of the electromagnetic steel sheets. FIG2 is a diagram illustrating a first connection portion provided in each slot according to one embodiment of the present invention, and is an enlarged view corresponding to the vicinity of the slot in FIG1. ​​FIG3 is a diagram illustrating a first connection portion provided in each slot according to another embodiment of the present invention, and is an enlarged view corresponding to the vicinity of the slot in FIG1. ​​FIG4 is a diagram illustrating a first connection portion provided around a plurality of slots according to another embodiment of the present invention, and is a cross-sectional view of the stator core viewed from the direction of the stacking of the electromagnetic steel sheets. FIG5 is a cross-sectional view showing a pressure fixture according to one embodiment of the present invention.

Claims

1. A stator core, characterized in that: the stator core comprises: a plurality of laminated electromagnetic steel plates; and connecting portions disposed between adjacent electromagnetic steel plates in the lamination direction, each electromagnetic steel plate comprising: an annular core back; a plurality of teeth protruding radially from the core back at intervals in the circumferential direction; and connecting portions connecting the front ends of adjacent teeth to each other, the connecting portions comprising a first connecting portion surrounding the space formed by the core back, the adjacent teeth, and the connecting portions of the plurality of electromagnetic steel plates, the first connecting portion comprising: a peripheral connecting portion disposed on the adjacent teeth; an inner connecting portion disposed on the connecting portion and connecting the radially inner sides of the peripheral connecting portions of each of the adjacent teeth to each other; and an outer connecting portion disposed on the core back and connecting the radially outer sides of the peripheral connecting portions of each of the adjacent teeth to each other. The compressive stress remaining in the region of the aforementioned connecting portion where the aforementioned inner bonding portion is provided is greater than at least one of the compressive stress remaining in the region of the aforementioned tooth portion where the aforementioned peripheral bonding portion is provided, or in the region of the aforementioned core back portion where the aforementioned outer bonding portion is provided.

2. The stator core of claim 1, wherein the aforementioned peripheral connecting portion is provided at the end closest to the aforementioned space of each of the aforementioned adjacent teeth, the aforementioned inner connecting portion is provided at least at the end of the aforementioned connecting portion in the radial direction outside, and the aforementioned outer connecting portion is provided at the end of the aforementioned core back in the radial direction inside.

3. A stator core, characterized in that: the stator core comprises: a plurality of laminated electromagnet plates; and connecting portions disposed between adjacent electromagnet plates in the lamination direction, each electromagnet plate comprising: an annular core back; a plurality of teeth protruding radially from the core back at intervals in the circumferential direction; and connecting portions connecting the front ends of adjacent teeth, the connecting portions comprising a first connecting portion surrounding the space formed by the core back, the adjacent teeth, and the connecting portions of the plurality of electromagnet plates, the first connecting portion having: The inner ring connection portion, which covers the front ends of the aforementioned plurality of teeth and the aforementioned plurality of connecting portions, is arranged in a ring shape; and the outer ring connection portion, which covers the aforementioned core back, is arranged in a ring shape, wherein the compressive stress remaining in the region of the aforementioned connecting portion where the aforementioned inner ring connection portion is provided is greater than the compressive stress remaining in at least one of the region of the aforementioned teeth where the aforementioned inner ring connection portion is provided, or the region of the aforementioned core back where the aforementioned outer ring connection portion is provided.

4. A stator core, characterized in that: the stator core comprises: a plurality of laminated electromagnetic steel plates; and bonding portions disposed between adjacent electromagnetic steel plates in the lamination direction, each electromagnetic steel plate comprising: an annular core back; a plurality of teeth protruding radially from the core back at intervals in the circumferential direction; and connecting portions connecting the front ends of adjacent teeth, the bonding portions comprising a first bonding portion and a second bonding portion, the first bonding portion surrounding the space formed by the core back, the adjacent teeth, and the connecting portions of the plurality of electromagnetic steel plates, the second bonding portion being disposed at a different position from the first bonding portion, the first bonding portion being solidified by a first adhesive of bonding strength corresponding to the pressure exerted during bonding, and the compressive stress remaining in the region of the connecting portion where the first bonding portion is disposed being greater than the compressive stress remaining in the region of the electromagnetic steel plate where the second bonding portion is disposed.

5. The stator core of claim 4, wherein the aforementioned second connection portion is disposed between the aforementioned electromagnetic steel plates in all portions not containing the aforementioned first connection portion.

6. A rotary electric motor, characterized in that it comprises a stator core as claimed in any one of claims 1 to 5.

7. A pressure fixture, characterized in that: it is used for manufacturing a stator core, the stator core having a plurality of stacked electromagnet plates and connecting portions respectively disposed between adjacent electromagnet plates in the stacking direction, the stator core having a plurality of teeth and connecting portions connecting adjacent teeth, the pressure fixture having a member having a concave-convex surface on the pressing surface, the pressing surface of the member being protruding at least at the position corresponding to the connecting portion.

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