Stator core, rotating electric machine, and pressurizing jig

Abstract

A stator core (30) is provided, comprising a plurality of laminated electromagnetic steel sheets (40) and adhesive portions (100) respectively disposed between adjacent electromagnetic steel sheets (40) in the lamination direction, wherein each electromagnetic steel sheet (40) includes an annular core back (41), a plurality of teeth (42) that project radially from the core back (41) at circumferential intervals, and a connecting portion (43) that connects the tips of adjacent teeth (42), and the adhesive portion (100) includes a first adhesive portion (110) that surrounds the space formed by the core back (41), adjacent teeth (42), and connecting portion (43) of the plurality of electromagnetic steel sheets (40).

Description

Technical Field

[0001] The present invention relates to a stator core, a rotating electric machine, and a pressing jig. This application claims priority based on Japanese Patent Application No. 2024-124581 filed in Japan on July 31, 2024, and incorporates its contents herein.

Background Art

[0002] As the electrification of automobiles progresses, motors used in electric vehicles are desired to be small and high-output. Also, motor thermal management has become an important issue. In response to this issue, in recent years, cooling technologies such as directly oil-cooling the inside of the motor have been adopted. As one of the cooling methods inside the motor, a technique has been studied in which a sealed structure is formed for each slot of the stator core, and a cooling medium is passed from the outside to directly cool the heat generated by the coil winding. For example, in Patent Document 1, in order to cool the winding inside the slot, the winding is moved closer to the inner diameter side inside the slot and a gap is provided on the outer diameter side to secure a path for air, which is the cooling medium.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, if the cooling medium leaks out of the slot area through gaps such as between the laminated electromagnetic steel sheets used to form the stator core, there is a concern that the cooling medium will act as resistance to the motor's rotational force. Furthermore, especially if the cooling medium is a liquid, if it leaks, it will be necessary to replenish the leaked cooling medium, requiring a structure or device to recover the leaked cooling medium, which raises concerns about increased costs. On the other hand, if additional components are required to create a sealed structure in the slot area to address cooling medium leakage, there are concerns about a decrease in the coil winding's space utilization ratio. Therefore, the inventors investigated a sealed structure for the stator core that requires as few additional components as possible.

[0005] The present invention has been made in view of the above, and aims to provide a stator core that can prevent the cooling medium flowing through the slots from leaking out of the stator core. [Means for solving the problem]

[0006] (1) A stator core according to one aspect of the present invention is Multiple laminated electrical steel sheets, A stator core comprising adhesive portions disposed between adjacent electrical steel sheets in the stacking direction, The aforementioned electrical steel sheets are, A ring-shaped core back, Multiple teeth that protrude radially from the core back at intervals in the circumferential direction, It includes a connecting portion that connects the tips of adjacent teeth, The adhesive portion includes a first adhesive portion that surrounds the space formed by the core backs, adjacent teeth, and connecting portions of the plurality of electrical steel sheets. fruit, The first adhesive portion is, The circumferential adhesive portion provided on each of the adjacent teeth, An inner adhesive portion is provided in the connecting portion, which connects the radially inner sides of the circumferential adhesive portions of each of the adjacent teeth, The core back has an outer adhesive portion that connects the radially outer sides of the circumferential adhesive portions of each of the adjacent teeth, The compressive stress remaining in the region of the connecting portion where the inner adhesive portion is provided is greater than at least one of the compressive stresses remaining in the region of the teeth where the circumferential adhesive portion is provided, or in the region of the core back where the outer adhesive portion is provided. .

[0007] (2) above In the stator core described in 1 ( ), the circumferential adhesion part is provided at the end closest to the space in each of the adjacent teeth, the inner adhesion part is provided at least at the radially outer end of the connecting part, the outer adhesion part may be provided at the radially inner end of the core back. (3) A stator core according to one aspect of the present invention is Multiple laminated electrical steel sheets, A stator core comprising adhesive portions disposed between adjacent electrical steel sheets in the stacking direction, The aforementioned electrical steel sheets are, A ring-shaped core back, Multiple teeth that protrude radially from the core back at intervals in the circumferential direction, It includes a connecting portion that connects the tips of adjacent teeth, The adhesive portion includes a first adhesive portion that surrounds the space formed by the core backs, adjacent teeth, and connecting portions of the plurality of electromagnetic steel sheets. The first adhesion part has an inner ring adhesion part provided annularly across the tips of the plurality of teeth and the plurality of connecting parts, and an outer ring adhesion part provided annularly across the core back. death, The compressive stress remaining in the region of the connecting portion where the inner ring adhesive portion is provided is greater than the compressive stress remaining in at least one of the region of the tip of the teeth where the inner ring adhesive portion is provided, or the region of the core back where the outer ring adhesive portion is provided. . (4) A stator core according to one aspect of the present invention is Multiple laminated electrical steel sheets, A stator core comprising adhesive portions disposed between adjacent electrical steel sheets in the stacking direction, The aforementioned electrical steel sheets are, A ring-shaped core back, Multiple teeth that protrude radially from the core back at intervals in the circumferential direction, It includes a connecting portion that connects the tips of adjacent teeth, The adhesive portion comprises a first adhesive portion that surrounds the space formed by the core backs, adjacent teeth, and connecting portions of the plurality of electromagnetic steel sheets, and A second adhesion part provided at a position different from the first adhesion part described and The first adhesive portion is formed by the solidification of a first adhesive that exhibits adhesive strength corresponding to the pressure applied during bonding. The compressive stress remaining in the region of the connecting portion where the first adhesive portion is provided is greater than the compressive stress remaining in the region of the electrical steel sheet where the second adhesive portion is provided. (5 ) In the stator core described in the above 4 ( ), The second adhesive portion may be provided in all portions between the electrical steel sheets where the first adhesive portion is not present.

[0008] ( 6 )A rotating electric machine according to one aspect of the present invention is as described above (1)~( 5 It comprises a stator core as described in any one of the items of the following paragraphs.

[0009] (7) A pressurizing jig according to one aspect of the present invention is A pressurizing jig used in the manufacture of a stator core comprising a plurality of laminated electromagnetic steel sheets and adhesive portions disposed between adjacent electromagnetic steel sheets in the lamination direction, The stator core The electromagnetic steel sheet that constitutes the teeth, Each consists of an annular core back and a radially projecting portion from the core back, spaced apart in the circumferential direction. Multiple teeth, Connecting the tips of adjacent teeth It has a connecting part, The adhesive portion includes a first adhesive portion that surrounds the space formed by the core backs, adjacent teeth, and connecting portions of the plurality of electromagnetic steel sheets, and a second adhesive portion provided at a different position from the first adhesive portion. The aforementioned pressurizing jig is The member has an uneven surface on the pressing surface, The pressing surface of the member protrudes at least at a position corresponding to the connecting portion. Furthermore, in the stacking direction, the region corresponding to the region forming the first adhesive portion protrudes more than the region corresponding to the region forming the second adhesive portion. It is characterized by having this feature. [Effects of the Invention]

[0010] According to the stator core of the present invention, it is possible to prevent the cooling medium flowing through the slots from leaking out of the stator core. [Brief explanation of the drawing]

[0011] [Figure 1] This is a diagram illustrating a rotating electric machine according to one embodiment of the present invention, and is a cross-sectional view of the stator and rotor of the rotating electric machine as seen from the lamination direction of the electromagnetic steel sheet. [Figure 2] This figure illustrates a first adhesive portion provided in each slot according to one embodiment of the present invention, and corresponds to an enlarged view of the vicinity of the slot in Figure 1. [Figure 3] This figure illustrates a first adhesive portion provided in each slot according to another embodiment of the present invention, and corresponds to an enlarged view of the vicinity of the slot in Figure 1. [Figure 4] This figure illustrates a first adhesive 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 as seen from the lamination direction of the electromagnetic steel sheet. [Figure 5] This is a cross-sectional view showing a pressurizing jig according to one embodiment of the present invention. [Modes for carrying out the invention]

[0012] The embodiments of the present invention will be described below with reference to examples, but it is obvious that the present invention is not limited to the examples described below. In the following description, specific numerical values ​​and materials may be given as examples, but other numerical values ​​and materials may be applied as long as the effects of the present invention are obtained. In addition, each component of the following embodiments can be combined with one another.

[0013] Figure 1 is a schematic diagram illustrating a rotating electric machine 1 comprising a stator 10 and a rotor 20. Note that Figure 1 omits other components of the rotating electric machine 1, as only those necessary for explanation are shown. Furthermore, coils in the stator 10, permanent magnets in the rotor 20, magnet insertion holes, air gaps, and the rotating shaft are also omitted. Figure 1 is a cross-sectional view of the stator 10 and rotor 20 of the rotating electric machine 1, viewed from the lamination direction of the electromagnetic steel sheets 40 (hereinafter also referred to as the lamination direction). It corresponds to a view of the rotating electric machine 1 cut perpendicular to the lamination direction between adjacent electromagnetic steel sheets 40 in the lamination direction. In other words, Figure 1 is a cross-sectional view of the stator 10 cut along the radial direction D, for example, between adjacent electromagnetic steel sheets 40. Hereafter, the radial direction D is the direction perpendicular to the central axis C of the stator 10. The circumferential direction R is the direction around the central axis C of the stator 10.

[0014] As shown in Figure 1, in the rotating electric machine 1, the stator 10 and rotor 20 are arranged sharing the same central axis C. Generally, the stator 10 and rotor 20 are constructed by laminating multiple electromagnetic steel sheets in the direction of their thickness. Adjacent electromagnetic steel sheets in the lamination direction of the stator 10 and rotor 20 are fixed to each other by adhesive, riveting, or a combination thereof. The stator 10 also has a stator core 30.

[0015] First, the stator core 30 according to this embodiment will be described with reference to Figure 1. As shown in Figure 1, the stator core 30 according to this embodiment comprises a plurality of stacked electromagnetic steel sheets 40 and adhesive portions 100 (first adhesive portions 110) arranged between adjacent electromagnetic steel sheets 40 in the stacking direction. Each electrical steel sheet 40 includes an annular core back 41 (annular in Figure 1), a plurality of teeth 42 that protrude radially D from the core back 41 at intervals in the circumferential direction R, and a connecting portion 43 that connects the tips of adjacent teeth 42.

[0016] In this embodiment, the teeth 42 protrude radially inward from the core back 41. That is, when viewed from the lamination direction (see Figure 1), if the outermost part of the annular core back 41 in the radial direction D is the outer edge 41e and the innermost part is the inner edge 41i, then each of the multiple teeth 42 extends so as to protrude from the inner edge 41i of the annular core back 41 in the direction toward the central axis C. The innermost end of the tooth 42 in the radial direction D is the tip of the tooth 42. When viewed from the lamination direction, the outer edge 41e of the core back 41 coincides with the side surface of the electrical steel sheet 40 (the surface whose length in the lamination direction is the thickness of the sheet). Furthermore, the tip of the tooth 42 is the portion including the tip of the tooth 42, and the connecting portion 43 may be connected to a portion of the tip of the tooth 42 other than the tip (a portion radially outward from the tip). Details of the adhesive portion 100 will be described later, but the adhesive portion 100 includes at least a first adhesive portion 110 and may further include a second adhesive portion 120.

[0017] As the multiple electromagnetic steel sheets 40 constituting the stator core 30 are stacked, the gaps formed inside by the two adjacent teeth 42 of each electromagnetic steel sheet 40, 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 a slot 44) that penetrates the stator core 30 in the stacking direction. A coil 50 (see Figures 2 and 3 described later) is housed inside this slot 44. The space inside the slot 44 where the coil 50 is not present is connected in the stacking direction so as to connect the outside of both ends of the slot 44 in the radial direction D, and is configured to allow the flow of a cooling medium such as cooling water, oil, or gas. The teeth 42 may also protrude radially outward from the core back (also called the yoke). Stator cores of this shape are used in outer rotor type rotating electric machines.

[0018] In the embodiment shown in Figure 1, the width of the connecting portion 43 (length in the radial direction D) is generally constant in the circumferential direction (the same applies to Figures 2 to 4 described later). However, the specific shape of the connecting portion 43 is arbitrary as long as it connects the tips of adjacent teeth 42. For example, there may be parts of the connecting portion 43 whose width differs from other parts, and for example, when viewed from the stacking direction, the edges of the connecting portion 43, such as the outer edge in the radial direction D, may be formed by one or more straight sections or arcs.

[0019] In the stator core 30 according to this embodiment, all of the laminated electromagnetic steel sheets 40 are provided with the connecting portion 43 described above, but some of the laminated electromagnetic steel sheets 40 may be provided with the connecting portion 43. In this case, in electromagnetic steel sheets that are not provided with the connecting portion 43 (not shown), instead of the connecting portion 43, the gap may be filled with a resin or the like (for example, the same material as the first adhesive portion 110) that is different from the electromagnetic steel sheet 40 so as to connect the adjacent tooth tips. This adhesive portion may be formed to the same thickness as the electromagnetic steel sheet so that the slot 44 is surrounded by the adhesive portion, thereby preventing leakage of the cooling medium from inside the slot 44. Furthermore, the thickness of each electromagnetic steel sheet 40 forming the stator core 30 may be appropriately determined considering the effect of improving magnetic properties such as iron loss improvement, manufacturing costs, and press punching workability.

[0020] Next, the adhesive portion 100 described above will be explained in detail using Figures 2 to 4. Figures 2 and 3 are enlarged views of the vicinity of slot 44 in Figure 1, and are diagrams illustrating the first adhesive portion 110 according to one embodiment of the present invention. Figure 4 is a cross-sectional view of a stator 10 different from the embodiments in Figures 1 to 3, viewed from the stacking direction, similar to Figure 1.

[0021] The adhesive portion 100 is provided on the surface of the electromagnetic steel sheets 40 (the sheet surface facing the lamination direction) where the laminated electromagnetic steel sheets 40 face each other. The adhesive portion 100 is formed when adhesive applied between adjacent electromagnetic steel sheets 40 has solidified (hardened). The adhesive portion 100 may bond two adjacent electromagnetic steel sheets 40 in the stator core 30 together. In other words, the adhesive portion 100 does not have to bond adjacent electromagnetic steel sheets 40 together in at least a portion of it. To put it another way, the adhesive portion 100 may include a first adhesive portion 110 that does not contribute to fixing the electromagnetic steel sheets 40 together by bonding, and an adhesive portion that contributes to fixing the electromagnetic steel sheets 40 together by bonding (for example, a second adhesive portion 120 described later). If the entire adhesive portion 100 does not bond adjacent electromagnetic steel sheets 40 together, the electromagnetic steel sheets 40 may be fixed together by other fixing means such as crimping. Examples of adhesives used as the adhesive portion 100 include thermosetting adhesives that rely on polymerization bonding, acrylic adhesives that cure at room temperature, anaerobic adhesives, instant adhesives, and elastomer-containing acrylic adhesives.

[0022] Alternatively, at least a portion of the adhesive portion 100 may be composed of an adhesive coating applied to the entire surface of the electromagnetic steel sheet 40. The adhesive coating is, for example, a type of adhesive that solidifies by heat treatment. In this case, two adjacent electromagnetic steel sheets 40 in the stator core 30 are bonded together by the adhesive coating. Bonding of the electromagnetic steel sheets 40 together by the adhesive coating is carried out using a pressure jig as described later. The adhesive may be applied over an insulating coating applied to the surface of the electromagnetic steel sheet 40, or it may be applied to the surface of the electromagnetic steel sheet 40 when there is no insulating coating on the surface of the electromagnetic steel sheet 40.

[0023] As shown in Figures 2 and 3, the adhesive portion 100 includes a first adhesive portion 110 that surrounds the slot 44 provided in the stator core 30. More specifically, as shown in Figures 2 and 3, the first adhesive portion 110 may have a circumferential adhesive portion 111, an inner adhesive portion 112, and an outer adhesive portion 113. The circumferential adhesive portion 111 is provided on each of two adjacent teeth 42 (for example, 42A and 42B). The inner adhesive portion 112 is provided on the connecting portion 43 and connects the radially inner sides of each circumferential adhesive portion 111 of adjacent teeth 42. The outer adhesive portion 113 is provided on the core back 41 and connects the radially outer sides of each circumferential adhesive portion 111 of adjacent teeth 42. The circumferential adhesive portion 111 may be provided along the radial direction D on each of two adjacent teeth 42.

[0024] In other words, when viewed from the stacking direction, in each slot 44 of the stator core 30, the first adhesive portion 110 is formed to surround the corresponding slot 44 by two circumferential adhesive portions 111 facing each other across the slot 44, an inner adhesive portion 112, and an outer adhesive portion 113. Furthermore, when viewed from the stacking direction, each of the first adhesive portions 110 is formed continuously without any discontinuity.

[0025] In the embodiment shown in Figure 2, the circumferential adhesive portion 111 is located at the end of each adjacent tooth 42 closest to the slot 44, away from the edge of each tooth 42 (slot circumferential edge 44a). In other words, the circumferential adhesive portion 111 is not located on the entire tooth 42, and is located at the circumferential end portion, spaced apart from the edge. Similarly, the outer adhesive portion 113 is located at the radially inner end of the core back 41 (not the entire core back 41, but the end portion), away from the slot outer edge 44c. Note that a portion of the inner edge 41i and the slot outer edge 44c overlap. The inner adhesive portion 112 is located at the radially outer end of the connecting portion 43, away from the radially outer edge (slot inner edge 44b). In Figure 2, the separation distances from the edges of the slots 44 (slot peripheral edge 44a, slot inner edge 44b, and slot outer edge 44c) of each part constituting the first adhesive portion 110 are generally the same, but there may be parts or positions with different separation distances.

[0026] With the above configuration, the first adhesive portion 110 surrounding the slot 44 can limit the area where the cooling medium leaks from the slot 44 to the electrical steel sheet 40 to the vicinity of the slot 44.

[0027] In the embodiment shown in Figure 3, the circumferential adhesive portion 111 is located at the end of each adjacent tooth 42 closest to the slot 44, and is positioned to overlap with the edge of each tooth 42 (slot circumferential edge 44a). In other words, the circumferential adhesive portion 111 is not located on the entire tooth 42, but is located at the circumferential end portion, and when viewed from the lamination direction, the end of the circumferential adhesive portion 111 coincides with the side surface of the electromagnetic steel sheet 40 that forms the slot 44. Similarly, the outer adhesive portion 113 is located at the radially inner end of the core back 41 (not the entire core back 41, but the end portion), and is positioned to overlap with the inner edge 41i of the core back 41 (slot outer edge 44c). The inner adhesive portion 112 is located at the radially outer end of the connecting portion 43, and is positioned to overlap with the radially outer edge (slot inner edge 44b). Furthermore, in at least a portion of each part constituting the first adhesive portion 110, the first adhesive portion 110 may extend to the inner wall of the slot 44.

[0028] With the above configuration, the first adhesive portion 110 surrounding the slot 44 is provided up to the edge of the slot 44, which prevents the cooling medium from leaking not only to the outside of the slot 44 but also to the spaces between adjacent electromagnetic steel sheets 40 (the surface of the electromagnetic steel sheets 40). Furthermore, assuming that the widths of each part constituting the first adhesive portion 110 are the same in Figures 2 and 3, Figure 3 has the advantage that the first adhesive portion 110 is located further away from the region where the magnetic flux mainly flows during operation (the region in the circumferential center of the teeth 42), so the first adhesive portion 110 is less likely to obstruct the flow of magnetic flux, and thus is expected to suppress the deterioration of motor characteristics. Furthermore, with the above configuration, no additional components are required to prevent leakage of the cooling medium. Therefore, space for additional components is not required, and the opening area of ​​the slot 44 can be secured. In addition, since no additional components are required with the above configuration, it is also advantageous from the standpoint of manufacturing efficiency.

[0029] In Figures 2 and 3, the inner adhesive portion 112 may be provided over the entire connecting portion 43. In Figure 3, the first adhesive portion 110 is provided up to the edge (side) of the electromagnetic steel sheet 40 forming the slot 44 at all positions when viewed from the lamination direction, but at least one of the two circumferential adhesive portions 111, the inner adhesive portion 112, and the outer adhesive portion 113, or at least one location of the first adhesive portion 110, may not be provided up to the edge.

[0030] Furthermore, the widths of the first adhesive portion 110, such as the width of the circumferential adhesive portion 111, the width of the inner adhesive portion 112, and the width of the outer adhesive portion 113, are not particularly limited, but should be set appropriately from the viewpoint of preventing leakage of the cooling medium. In addition, the viewpoint of iron loss degradation may also be considered, in which case the width of the adhesive portion should be set appropriately considering both leakage prevention and iron loss degradation. Here, the width of the adhesive portion refers to the length of the adhesive portion in the direction perpendicular to the longitudinal direction (extension direction) of the adhesive portion, when viewed from the lamination direction.

[0031] As explained above using Figures 2 and 3 (and similarly Figure 1), the first adhesive portion 110 is composed of a circumferential adhesive portion 111, an inner adhesive portion 112, and an outer adhesive portion 113. As a result, each slot 44 of the stator core 30 is completely surrounded by multiple first adhesive portions 110 and multiple electromagnetic steel sheets 40 arranged alternately in the lamination direction. This prevents the cooling medium flowing through the slot 44 from leaking out of the slot 44 (Figure 3) or from remaining near the slot 44 (Figure 2). Therefore, leakage of the cooling medium from the stator core 30 to the outside can be prevented.

[0032] Alternatively, as shown in Figure 4, the first adhesive portion 110 may have an inner ring adhesive portion 121 that is continuously provided in an annular shape across the tips of the multiple teeth 42 and the multiple connecting portions 43 that form the inner peripheral edge of the annular stator core 30, and an outer ring adhesive portion 122 that is continuously provided in an annular shape across the core back 41. The inner ring adhesive portion 121 and the outer ring adhesive portion 122 are each formed continuously without interruption. That is, when viewed from the stacking direction, multiple slots 44 are surrounded by the inner ring adhesive portion 121 and the outer ring adhesive portion 122.

[0033] In the embodiment shown in Figure 4, the outer ring adhesive portion 122 is formed in an annular (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 adhesive portion 122 may be provided in an annular shape in a region closer to the inner edge 41i side or the outer edge 41e side of the core back 41 than to the central region of the core back 41. The closer the outer ring adhesive portion 122 is to the inner edge 41i of the core back 41, the smaller the range of cooling medium that leaks from the slot 44 into the electromagnetic steel sheet 40. The closer the outer ring adhesive portion 122 is to the outer edge 41e of the core back 41, the further the outer ring adhesive portion 122 is from the region where magnetic flux mainly flows during the operation of the rotating electric machine (the region radially inward of the core back 41), thereby reducing the deterioration of magnetic properties such as iron loss due to compressive stress (strain) applied to the electromagnetic steel sheet 40 by the solidification of the adhesive. Furthermore, the fact that iron loss increases when compressive stress (elastic compressive stress) is applied to steel plates is described, for example, in the literature by Yabumoto et al. (Nippon Steel Technical Report No. 378, pp. 51-54 (2003)).

[0034] Furthermore, in the embodiment shown in Figure 4, the inner ring adhesive portion 121 and the outer ring adhesive portion 122 each have an annular shape with a generally constant width, but at least one of them may include a straight portion, a wave-shaped portion, a curved portion with a different curvature from the others in at least a part, or it may have a portion with a different width from the other portion, or a portion may be present on the teeth 42, or a combination of these may be included. The width of the first adhesive portion 110 means the length in the direction perpendicular to the longitudinal direction (extension direction) of the adhesive portion when viewed from the lamination direction. The widths of the inner ring adhesive portion 121 and the outer ring adhesive portion 122 are arbitrary. In addition, each of the inner ring adhesive portion 121 and the outer ring adhesive portion 122 may be composed of one or more annular adhesive portions spaced apart in the radial direction D. If the outer ring adhesive portion 122 includes a plurality of annular adhesive portions, the outer ring adhesive portion 122 may be composed of a plurality of annular adhesive portions provided at intervals along the radial direction D in at least a portion of the core back 41, such as the central region described above. The outer ring adhesive portion 122 may be provided over the entire surface of the core back 41. Also, if the inner ring adhesive portion 121 includes a plurality of annular adhesive portions, the inner ring adhesive portion 121 may be composed of a plurality of annular adhesive portions provided at intervals along the radial direction D in the tip portion and connecting portion 43 of the teeth 42.

[0035] In this way, each slot 44 is surrounded by a first adhesive portion 110 having an inner ring adhesive portion 121 and an outer ring adhesive portion 122, thereby preventing the cooling medium from leaking out of the stator core 30.

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

[0037] Next, we will explain the contents other than the configuration of the first adhesive portion 110 described above. The first adhesive portion 110 may be formed by the solidification of a first adhesive that exhibits adhesive strength corresponding to the pressure applied during bonding. The adhesive strength of this first adhesive changes depending on the pressure applied during bonding. For example, the higher the pressure applied during bonding, the higher the adhesive strength after solidification. The application area of ​​such a first adhesive may be the entire surface between adjacent electrical steel sheets 40, or at least around the slots 44 (Figures 2 and 3) or in the area surrounding multiple slots 44 (Figure 4), or at least on a part of the surface of the stator core 30, and the first adhesive portion 110 may be formed by bonding only the area that will become the first adhesive portion 110 with locally stronger pressure than other areas. When the first adhesive is applied to the entire surface, an adhesive coat may be formed by the first adhesive. The adhesive that forms the adhesive coat may be an adhesive that hardens by heat treatment. Applying adhesive to each punched-out stator core individually is time-consuming and prone to uneven application. However, applying the adhesive in a coating (film-like) manner has the advantage of suppressing uneven application and making it easier to achieve a uniform stacking thickness. As a result, the adhesive portion 100 will include the first adhesive portion 110 and other adhesive portions. Examples of adhesives that can be used as the first adhesive include thermosetting adhesives that rely on polymerization bonding, acrylic adhesives, room-temperature curing adhesives, anaerobic adhesives, instant adhesives, and elastomer-containing acrylic adhesives.

[0038] According to the above configuration, by locally and strongly bonding only the region forming the first adhesive portion 110 in adjacent electrical steel sheets 40, the adjacent electrical steel sheets are bonded together by the first adhesive portion 110, and the region forming the first adhesive portion 110 is bonded relatively more strongly than other regions (for example, the region that will become the second adhesive portion 120, as described later). This makes it possible to increase the contribution of the first adhesive portion 110 to the fixing force between the electrical steel sheets 40 compared to when a uniform adhesive strength is provided. Therefore, it becomes possible to secure the fixing force required for the stator core even if the adhesive strength of the parts of the adhesive portion 100 other than the first adhesive portion 110 is further reduced, or the area of ​​those parts is further reduced. For this reason, by reducing the adhesive strength of the areas other than the first adhesive portion 110, the adhesive strength in the region where the magnetic flux mainly flows during operation can be reduced, thereby reducing the effect of increased iron loss due to compressive stress applied to the electrical steel sheets 40 by the adhesive portion 100. Therefore, it is possible to prevent the cooling medium from flowing out (leaking) from the inside of the slot 44 to the outside while suppressing the degradation of the overall characteristics of the stator 10.

[0039] Furthermore, the compressive stress remaining in the region where the first adhesive portion 110 is provided in the connecting portion 43 of the electrical steel sheet 40 (residual compressive stress) may be greater than the compressive stress remaining in the region where the first adhesive portion 110 is provided in the portion of the electrical steel sheet 40 other than the connecting portion 43.

[0040] The compressive stress remaining in the electrical steel sheet 40 can be measured, for example, by the X-ray diffraction method described in the Standard for X-Ray Stress Measurement (2002 edition) = Iron and Steel = (JSMS-SD-5-02), published by the Japan Society for Materials Science. When measuring the residual compressive stress in the electrical steel sheets 40 using X-ray diffraction, the stator 10 is divided in the stacking direction at the adhesive joint 100 between the electrical steel sheets 40. When dividing the stator 10 in the stacking direction, there are no particular limitations, but one method is to push a tool into the gap (adhesive joint 100) between the electrical steel sheets 40 and apply force starting from this tool to split the stator 10 into two. Alternatively, the adhesive joint 100 may be cut to divide the stator 10 into two. In this way, the adhesive joint 100 between the electrical steel sheets 40 is exposed. The presence or absence of the adhesive joint 100 can be confirmed by visually inspecting the collected electrical steel sheet 40, but the residual compressive stress in the electrical steel sheet 40 is measured by preparing a sample suitable for the above-mentioned X-ray diffraction method from the collected electrical steel sheet 40. When using X-ray diffraction, if the adhesive joint 100 is present on the surface of the electrical steel sheet 40, the X-rays will not penetrate to the desired depth of the electrical steel sheet 40, so it is desirable to remove the adhesive joint 100. On the other hand, when visually checking the application state (shape, etc.) of the adhesive part 100, it is preferable for traces of the adhesive part 100 to remain.

[0041] For example, in the case where the first adhesive portion 110, as shown in Figures 2 and 3, is composed of a circumferential adhesive portion 111, an inner adhesive portion 112, and an outer adhesive portion 113, the compressive stress remaining in the region of the connecting portion 43 where the inner adhesive portion 112 is provided may be greater than at least one of the compressive stresses remaining in the region of the teeth 42 where the circumferential adhesive portion 111 is provided, or in the region of the core back 41 where the outer adhesive portion 113 is provided.

[0042] Furthermore, in the case where the first adhesive portion 110 is composed of an inner ring adhesive portion 121 and an outer ring adhesive portion 122, as shown in Figure 4, the compressive stress remaining in the region of the connecting portion 43 where the inner ring adhesive portion 121 is provided may be greater than the compressive stress remaining in either or both of the region of the tip of the teeth 42 where the inner ring adhesive portion 121 is provided or the region of the core back 41 where the outer ring adhesive portion 122 is provided.

[0043] When the tips of adjacent teeth 42 are connected by the connecting portion 43, magnetic flux can flow through the connecting portion 43 during the operation of the rotating electric machine 1, which is undesirable from the perspective of the performance of the rotating electric machine 1. Therefore, in this embodiment, by utilizing the fact that the magnetic properties of the electromagnetic steel sheet 40 deteriorate due to the solidification of the adhesive, the first adhesive is solidified under high pressure so that a stronger adhesive strength (adhesive force) than required for adhesive fixing is exerted on the connecting portion 43. This makes it possible to actively increase the iron loss of the connecting portion 43, making it difficult for magnetic flux to flow through the connecting portion 43. Thus, it is possible to suppress the deterioration of motor characteristics due to the flow of magnetic flux through the connecting portion 43.

[0044] Such a distribution of residual compressive stress in the first adhesive portion 110 may be formed, for example, by using two or more different types of adhesives and by uniformly applying pressure to the surface of the laminated electrical steel sheets 40 when joining them together. In this case, among the different adhesives, for example, the adhesive that solidifies to form the first adhesive portion 110 may be called the first adhesive, and the adhesive that solidifies to form the second adhesive portion 120 may be called the second adhesive. Alternatively, the distribution of residual compressive stress may be achieved by using the first adhesive described above to form the first adhesive portion 110, and by applying pressure while changing the pressure distribution during joining. In the manufacturing of the stator core 30, electrical steel sheets 40 coated with adhesive to form the bonding portion 100 are stacked, and the stacked electrical steel sheets 40 are joined by applying pressure in the direction of stacking. The pressure is applied, for example, by a pressure device that presses the stator core 30, via a pressure jig that presses the stator core 30. The pressure distribution on the surface of the electrical steel sheet 40 during bonding can be adjusted by this pressure jig by forming irregularities on the jig. For example, a pressure jig that can apply locally higher pressure may be used by making the part that forms the connecting portion 43 in the first bonding portion 110 protrude in a direction that applies more pressure than other parts. By using such a pressure jig, the pressure distribution on the surface of the electrical steel sheet 40 during bonding can be arbitrarily set. An example of a pressure jig will be described later.

[0045] According to the above configuration, the adhesive strength of the portion of the first adhesive portion 110 corresponding to the connecting portion 43 is intentionally made greater than the adhesive strength of the portions corresponding to the core back 41 and teeth 42. By increasing the iron loss in the connecting portion 43, magnetic flux can be made less likely to flow in the connecting portion 43, thereby suppressing the deterioration of motor characteristics.

[0046] Furthermore, the multiple electromagnetic steel sheets 40 constituting the stator core 30 as shown in Figures 1 to 4 may be fixed by an adhesive portion 100 that includes the first adhesive portion 110 described above and a second adhesive portion 120 provided at a different position from the first adhesive portion 110. In this case, the second adhesive portion 120 may be provided in at least a part of the area on the surface of each electromagnetic steel sheet 40 where the first adhesive portion 110 is not located, or it may be provided in the entire area. In particular, if the entire surface of the electromagnetic steel sheet 40 is covered by the adhesive portion 100 including the first adhesive portion 110 and the second adhesive portion 120, the adhesive portion 100 may be formed by the solidification of the first adhesive under the pressure distribution described above.

[0047] When the adhesive portion 100 covers the space between adjacent electrical steel sheets 40 in the lamination direction by the first adhesive portion 110 and the second adhesive portion 120, the compressive stress remaining in the region of the electrical steel sheet 40 where the first adhesive portion 110 is provided may be greater than the compressive stress remaining in the region of the electrical steel sheet 40 where the second adhesive portion 120 is provided. Such a distribution of residual compressive stress may be formed, for example, by using two or more different types of adhesives and applying uniform pressure to the surface of the laminated electrical steel sheets. Alternatively, the adhesives used to form the first adhesive portion 110 and the second adhesive portion 120 may be of the same type in the electrical steel sheet 40, and the first adhesive and pressure jig described above may be used to form the first adhesive portion 110 and the second adhesive portion 120. Furthermore, the compressive stress remaining in at least the region of the connecting portion 43 within the region of the electrical steel sheet 40 where the first adhesive portion 110 is provided may be greater than the compressive stress remaining in the region of the electrical steel sheet 40 where the second adhesive portion 120 is provided.

[0048] For example, in the examples shown in Figures 1 to 4, if the entire surface area of ​​the electromagnetic steel sheet 40 that lacks the first adhesive portion 110 is to be made into the second adhesive portion 120, the first adhesive described above is applied between all adjacent electromagnetic steel sheets, and the first adhesive is solidified by applying pressure through a pressure jig with irregularities such that the area corresponding to the first adhesive portion 110 becomes a convex portion and the area corresponding to the second adhesive portion 120 becomes a concave portion. In this way, an adhesive portion 100 is formed in Figures 1 to 4 where the entire area that lacks the first adhesive portion 110 becomes the second adhesive portion 120.

[0049] According to the above configuration, the stator core 30 is fixed by adhesive joint 100, which includes a first adhesive joint 110 and a second adhesive joint 120. This prevents the cooling medium flowing through the slots 44 from leaking out of the stator core 30 while firmly fixing the stator core 30. Furthermore, if the second adhesive joint 120 is provided in all areas between the electromagnetic steel sheets 40 where the first adhesive joint 110 is not present, the entire surface of the electromagnetic steel sheets 40 will be bonded by the first adhesive joint 110 and the second adhesive joint 120, thereby further improving the ability to prevent cooling medium leakage and the fixing strength of the stator core 30.

[0050] However, the present invention is not limited to the embodiments described above. The adhesive portion 100 may not include the second adhesive portion 120, and may consist only of the first adhesive portion 110. For example, the first adhesive portion 110 may be formed by applying the first adhesive described above only to the portion that forms the first adhesive portion 110 and allowing it to solidify. Alternatively, instead of the second adhesive portion 120, the multiple electromagnetic steel sheets 40 constituting the stator core 30 may be fixed by other fixing means. Other fixing means include riveting and welding.

[0051] (Pressure jig) The following describes a pressurizing jig 200 that can be used in the manufacture of the stator core 30 according to the above embodiment. Figure 5 is a schematic diagram showing an example of use of the pressurizing jig 200. The pressurizing jig 200 is used when pressure must be applied for bonding. For example, it is mainly used when an adhesive coating (adhesive film) is applied to an electrical steel sheet 40.

[0052] The pressurizing jig 200 is a jig used during the manufacturing of the stator core 30 to press and fix a core portion (hereinafter referred to as the core portion P) which is made up of multiple electromagnetic steel sheets 40 that make up the stator core 30, with adhesive in between. As shown in Figure 5, the pressurizing jig 200 includes a first member 210 having irregularities on the pressing surface 211 that presses against the core portion P while in contact with it. The core portion P is then bonded by applying pressure to it via the first member 210 using the pressing part 201 of the pressing device. The core portion P may also be heated to a predetermined temperature before applying pressure.

[0053] More specifically, the pressing surface 211 of the first member 210 protrudes more in the position (region) corresponding to the area forming the first adhesive portion 110 than in the position (region) corresponding to the area forming the second adhesive portion 120 in the stacking direction of the stator core 30. In other words, the position corresponding to the first adhesive portion 110 is convex in the stacking direction of the stator core 30, and the position corresponding to the second adhesive portion 120 is concave in the stacking direction of the stator core 30. Thus, the pressing surface 211 has a first pressing portion 211A (convex portion) configured to press relatively strongly against the position corresponding to the first adhesive portion 110, and a second pressing portion 211B (concave portion) configured to press relatively weakly against the position corresponding to the second adhesive portion 120.

[0054] In short, the pressing jig 200 has an uneven surface on its pressing surface 211 such that, during bonding, the pressing force in a desired area of ​​the core portion P is higher than in other areas. The shape of the unevenness of the pressing surface 211 in a plan view of the stator core 30 from the stacking direction is designed according to the shape and position of the first bonding portion 110. As a result, the pressure during pressing is higher in the areas corresponding to the convex areas than in the areas corresponding to the concave areas. Therefore, if the adhesive used to bond and fix the stator core 30 is of a type that exhibits adhesive 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 in a single step.

[0055] In the embodiment shown in Figure 5, the pressurizing jig 200 (first member 210) is a plate-shaped member with irregularities formed on it, such as a mold formed on a metal plate of a predetermined thickness with irregularities in the thickness direction. Furthermore, when pressed by the pressing part 201, the first pressing part 211A of the first member 210 presses a predetermined portion of the electromagnetic steel sheet 40, and the second pressing part 211B presses an area other than the predetermined portion. The predetermined portion includes at least a position corresponding to the connecting part 43, but may also include a position corresponding to the entire portion of the first adhesive part 110. On the pressing surface 211, the predetermined portion protrudes more than at least a part of its surroundings, so that the protruding predetermined portion corresponds to a convex part, and at least a part of the area around the convex part corresponds to a concave part.

[0056] Furthermore, the pressing surface 211 includes 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 and are formed so that the pressing force changes gradually. As a configuration in which the pressing force changes gradually, for example, the tapered portion 212 may be gradually inclined at a constant rate, or it may change quadratically.

[0057] Furthermore, in the embodiment shown in Figure 5, the first member 210 is positioned above the core portion P with its pressing surface 211 facing downwards. The core portion P is supported from below by placing it on the upper surface of the second member 220, which is fixedly positioned below the core portion P. The first member 210 is then pressed in the direction of arrow F (downward in the stacking direction) by the pressing part 201 of the pressing device, thereby applying pressure to the core portion P and performing adhesive fixing.

[0058] However, the present invention is not limited to the embodiments described above. For example, the first member 210 may be positioned below and the second member 220 above. In addition to the first member 210, the support surface of the core portion P of the second member 220 may also have irregularities formed 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 do not necessarily have a tapered portion 212, and may be connected, for example, by a single stepped portion.

[0059] Note that Figure 5 is a simplified representation of the shape of the pressurizing jig 200 for clarity, and the actual dimensions of the pressurizing jig 200 may differ. For example, in the view shown by the arrow in Figure 5 (side view of the stator core 30), a difference H (μm) in the unevenness of the pressing surface 211 is provided. The difference H may be determined based on the relationship between the adhesive pressurizing conditions, which have been determined in advance by experiments or calculations, and the strength improvement allowance of the electromagnetic steel sheet 40 due to the provision of the first adhesive portion 110.

[0060] According to the pressurizing jig 200 described above, the irregularities formed on the pressing surface 211 allow for a pressure distribution on the surface of the electromagnetic steel sheet 40 with a single application of pressure. Therefore, during adhesive fixing, a single application of pressure allows for a higher pressure to be applied to the area where the first adhesive portion 110 of the electromagnetic steel sheet 40 is to be formed than to the area where the second adhesive portion 120 is to be formed. Consequently, the first adhesive portion 110 and the second adhesive portion 120 can be formed efficiently, thereby reducing the manufacturing cost of the stator core 30.

[0061] (Rotating electric machine) The rotating electric machine according to this embodiment includes the stator core of the embodiment described above. Since the rotating electric machine according to this embodiment includes the stator 10 described above, leakage of the cooling medium from the stator core 30 is prevented, and a structure or device for recovering the leaked cooling medium is unnecessary. Furthermore, "rotating electric machine" refers to a motor or generator. The motor is not particularly limited, and the motor type may be, for example, an IPM (Interior Permanent Magnet) motor, an IM (Induction Motor), or an EESM (Electrically Excited Synchronous Motor). The rotating electric machine may also be an outer rotor type motor. [Industrial applicability]

[0062] The stator core according to the present invention prevents the cooling medium flowing through the slots from leaking out of the stator core. Furthermore, since the rotating electric machine according to the present invention is equipped with the stator described above, leakage of the cooling medium from the stator core is prevented, eliminating the need for structures or devices to recover leaked cooling medium. In addition, by using the pressurizing jig according to the present invention, adhesive portions having a first adhesive portion and a second adhesive portion can be efficiently formed. For this reason, the present invention is extremely useful in industry. [Explanation of symbols]

[0063] 1. Rotating electric machine 10 staters 20 rotors 30 stator cores 40 Electrical steel sheet 41 Coreback 41e Outer edge 41i inner edge 42 Teeth 43 Connecting part 44 slots 44a Slot peripheral edge 44b Inner edge of slot 44c slot outer edge 50 coils 100 Adhesive part 110 1st adhesive part 111 Circumferential adhesive part 112 Inner adhesive part 113 Outside adhesive part 120 2nd adhesive part 121 Inner ring adhesive part 122 Outer ring adhesive part 200 Pressurizing fixtures 201 Pressing part 210 First Member 211 Pressing surface 211A First pressing section 211B Second pressing section 212 Tapered section 220 Second Member

Claims

1. Multiple laminated electrical steel sheets, A stator core comprising adhesive portions disposed between adjacent electrical steel sheets in the stacking direction, The aforementioned electrical steel sheets are, A ring-shaped core back, Multiple teeth that protrude radially from the core back at intervals in the circumferential direction, It includes a connecting portion that connects the tips of adjacent teeth, The adhesive portion includes a first adhesive portion that surrounds the space formed by the core backs, adjacent teeth, and connecting portions of the plurality of electromagnetic steel sheets. The first adhesive portion is, The circumferential adhesive portion provided on each of the adjacent teeth, An inner adhesive portion is provided in the connecting portion, which connects the radially inner sides of the circumferential adhesive portions of each of the adjacent teeth, The core back has an outer adhesive portion that connects the radially outer sides of the circumferential adhesive portions of each of the adjacent teeth, The compressive stress remaining in the region of the connecting portion where the inner adhesive portion is provided is greater than at least one of the compressive stress remaining in the region of the teeth where the circumferential adhesive portion is provided, or in the region of the core back where the outer adhesive portion is provided. A stator core characterized by the following features.

2. The circumferential adhesive portion is provided at the end of each of the adjacent teeth closest to the space, The inner adhesive portion is provided at least at the radially outer end of the connecting portion, The outer adhesive portion is provided at the radially inner end of the core back. The stator core according to feature 1.

3. Multiple laminated electrical steel sheets, A stator core comprising adhesive portions disposed between adjacent electrical steel sheets in the stacking direction, The aforementioned electrical steel sheets are, A ring-shaped core back, Multiple teeth that protrude radially from the core back at intervals in the circumferential direction, It includes a connecting portion that connects the tips of adjacent teeth, The adhesive portion includes a first adhesive portion that surrounds the space formed by the core backs, adjacent teeth, and connecting portions of the plurality of electromagnetic steel sheets. The first adhesive portion is, An inner ring adhesive portion is provided in an annular shape across the tip portions of the plurality of teeth and the plurality of connecting portions, It has an outer ring adhesive portion provided in an annular shape across the core back, The compressive stress remaining in the region of the connecting portion where the inner ring adhesive portion is provided is greater than the compressive stress remaining in at least one of the region of the tip of the teeth where the inner ring adhesive portion is provided, or the region of the core back where the outer ring adhesive portion is provided. A stator core characterized by the following features.

4. Multiple laminated electrical steel sheets, A stator core comprising adhesive portions disposed between adjacent electrical steel sheets in the stacking direction, The aforementioned electrical steel sheets are, A ring-shaped core back, Multiple teeth that protrude radially from the core back at intervals in the circumferential direction, It includes a connecting portion that connects the tips of adjacent teeth, The adhesive portion includes a first adhesive portion that surrounds the space formed by the core backs, adjacent teeth, and connecting portions of the plurality of electromagnetic steel sheets, and a second adhesive portion provided at a different position from the first adhesive portion. The first adhesive portion is formed by the solidification of a first adhesive that exhibits adhesive strength corresponding to the pressure applied during bonding. The compressive stress remaining in the region where the first adhesive portion is provided in the connecting portion is greater than the compressive stress remaining in the region where the second adhesive portion is provided in the electrical steel sheet. A stator core characterized by the following features.

5. The second adhesive portion is provided in all parts between the electrical steel sheets where the first adhesive portion is not present. The stator core according to feature 4.

6. A stator core comprising the stator core according to any one of claims 1 to 5, A rotating electric machine characterized by the following features.

7. A pressurizing jig used in the manufacture of a stator core comprising a plurality of laminated electromagnetic steel sheets and adhesive portions disposed between adjacent electromagnetic steel sheets in the lamination direction, Each of the electromagnetic steel sheets constituting the stator core has an annular core back, a plurality of teeth that protrude radially from the core back at circumferential intervals, and a connecting portion that connects the tips of adjacent teeth. The adhesive portion includes a first adhesive portion that surrounds the space formed by the core backs, adjacent teeth, and connecting portions of the plurality of electromagnetic steel sheets, and a second adhesive portion provided at a different position from the first adhesive portion. The aforementioned pressurizing jig is The member has an uneven surface on the pressing surface, The pressing surface of the member protrudes at least at a position corresponding to the connecting portion, and in the stacking direction, the region corresponding to the region forming the first adhesive portion protrudes more than the region corresponding to the region forming the second adhesive portion. A pressurizing jig characterized by the following features.

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