Stator

Abstract

To solve the problem that in a conventional stator, when the stator core as a laminate of steel plates is microscopically viewed, many fine air gaps due to step differences between the steel plates exist, the heat dissipation from the stator core to the stator holder might be reduced.SOLUTION: A stator S includes a cylindrical stator core 1 formed by laminating steel plates 1A, a cylindrical housing 2 shrink-fitted to its outer periphery, and a resin material 4 filling a space between the stator core 1 and the housing 2, and sufficiently secures a substantial contact area between the stator core 1 and the housing 2 and achieves improvement of heat dissipation property.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a stator used in a rotating electrical machine such as a motor or a generator. [Background technology]

[0002] An example of a conventional stator is described in Patent Document 1. Patent Document 1 describes a motor in which a stator and a rotor are housed in a housing. The stator includes a stator core made of laminated steel plates, a coil wound around the stator core, a resin part covering the coil ends, and a cylindrical stator holder fixed to the outer periphery of the stator core. The motor is provided with a flow path for a cooling fluid between the stator holder and the housing, and is configured to release heat generated by the coil into the flow path via the stator holder and the resin part. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6330938 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the stator described above uses a stator core made by laminating a large number of electromagnetic steel plates punched out by a press. Therefore, when viewed microscopically, there are steps between the steel plates, and these steps create many tiny air gaps. This reduces the contact area between the stator core and the stator holder, which could reduce heat dissipation.

[0005] The present invention has been made in consideration of the above-mentioned conventional situation, and aims to provide a stator having a structure in which a housing is shrink-fitted onto the outer periphery of a stator core made of laminated steel plates, which can ensure a sufficient actual contact area between the stator core and the housing, thereby improving heat dissipation. [Means for solving the problem]

[0006] The stator of the present invention is a stator comprising a cylindrical stator core made of laminated steel plates and a cylindrical housing shrink-fitted to its outer periphery, and is characterized by having a resin material filling the space between the stator core and the housing. [Effects of the Invention]

[0007] By adopting the above-described configuration, the stator of the present invention eliminates the minute air gap that occurs between the stator core and the housing due to the resin material, thereby ensuring a sufficient actual contact area between the stator core and the housing and improving heat dissipation from the stator core to the housing. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view with an enlarged view showing a first embodiment of a stator according to the present invention. [Figure 2] FIG. 2 is a cross-sectional view of a main part of the stator shown in FIG. [Figure 3] 2A and 2B are cross-sectional views illustrating two examples of a method for manufacturing the stator shown in FIG. 1. [Figure 4] FIG. 10 is an enlarged perspective view of a housing according to a second embodiment of the present invention. [Figure 5] 5 is a cross-sectional view of a main part of a stator having a housing shown in FIG. 4. [Figure 6] FIG. 10 is an enlarged perspective view of a housing according to a third embodiment of the present invention. [Figure 7] FIG. 10 is a perspective view of a housing according to a fourth embodiment of the present invention. [Figure 8] FIG. 10 is an enlarged perspective view of a housing according to a fifth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] First Embodiment The stator S shown in Fig. 1 includes a cylindrical stator core 1 and a cylindrical housing 2 shrink-fitted onto the outer periphery of the stator core 1. The stator core 1 is made by laminating a number of steel plates (electromagnetic steel plates) 1A punched out by a press, and has coils 3 wound in slots (not shown). The housing 2 is made of metal, and in the illustrated example, has an outward flange 2A at one end in the axial direction (the lower end in the figure).

[0010] The above-mentioned stator core 1 is made of a large number of press-formed steel plates 1A. As shown in the upper part of the enlarged view in Figure 1, when viewed microscopically, there are steps between the steel plates 1A, and these steps result in the existence of a minute air gap (gap) A between the stator core 1 and the housing 2.

[0011] In contrast, the stator S of this embodiment, as shown in the lower enlarged view of Fig. 1, is provided with a resin material 4 that fills a gap (A) between the outer peripheral surface of the stator core 1 and the inner peripheral surface of the housing 2. The resin material 4 is not particularly limited, but it is preferable to use a thermosetting resin with high thermal conductivity, which hardens to form a resin layer.

[0012] The stator S having the above-described configuration forms a rotating electrical device such as a motor or generator by inserting a rotor (not shown) into the center of the stator core 1. The resin material 4 eliminates the minute air gap A that occurs between the stator core 1 and the housing 2, thereby ensuring a sufficient contact area between the stator core 1 and the housing 2.

[0013] As a result, the stator S can quickly transfer heat generated in the coil 3 from the stator core 1 to the housing 2, improving heat dissipation. Furthermore, as shown in Fig. 2, the stator S has resin material 4 filling the gaps between the steel plates 1A, eliminating minute air gaps and providing an anchor effect in which the resin material 4 is attached to the stator core 1 as indicated by the arrows in the figure, thereby increasing the bonding strength between the stator core 1 and the housing 2.

[0014] As shown in Fig. 3(A), the above-mentioned stator S can be manufactured by heating the housing 2, applying or injecting a resin material 4 onto the inner peripheral surface of the housing 2, and then shrink-fitting the housing 2 onto the outer periphery of the stator core 1. Alternatively, as shown in Fig. 3(B), the stator S can be manufactured by heating the housing 2 and applying or injecting a resin material 4 onto the outer peripheral surface of the stator core 1, and then shrink-fitting the housing 2 onto the outer periphery of the stator core 1.

[0015] 4 to 8 are diagrams illustrating second to fifth embodiments of the present invention. In the following embodiments, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0016] Second Embodiment 4 is a diagram showing a housing in a second embodiment of the stator. The illustrated housing 2 has grooves arranged on its inner circumferential surface in the shrink-fit range of the stator core 1. The grooves in the illustrated example are circumferential grooves G1 that are continuous in the circumferential direction of the housing 2, and the circumferential grooves G1 are arranged at predetermined intervals in the axial direction of the housing 2 (the vertical direction in FIG. 4).

[0017] The depth of the groove (G1) is set to a value smaller than the minimum value calculated from variations in assembly of the steel plate 1A in the radial direction, etc. Therefore, the depth of the groove (G1) is extremely small, so that it has very little effect on the shrink fitting operation of the stator core 1. The depth of the groove (G1) is, for example, several μm to several hundred μm, and the total area is about 10% of the surface area of ​​the inner surface of the housing 2.

[0018] The grooves (G1) can be formed by anodizing, shot peening, laser processing, etc., and it is desirable to determine the number of grooves, width dimensions, etc. to be set based on the tendency of manufacturing variations such as Cpk (process capability index).

[0019] Here, as shown in Figure 3 described in the first embodiment, a stator equipped with the housing 2 is manufactured by applying resin to the outer peripheral surface of the stator core 1 or the inner peripheral surface of the housing 2, and then press-fitting (shrink-fitting) the housing 2 into the stator core 1. However, there is a risk that the resin may peel off during the press-fitting.

[0020] In contrast, a stator including the above-described housing 2 can obtain the same effects as the first embodiment, and in addition, the resin can be retained in the groove (G1), which prevents the resin from peeling off when the housing 2 is pressed in. Furthermore, in this embodiment, the circumferential groove G1 that is continuous in the circumferential direction of the housing 2 is employed, which makes it easier to retain the resin and more reliably prevents the resin from peeling off when the housing 2 is pressed in.

[0021] Furthermore, by employing the circumferential groove G1 in the above-described stator, the resin material 4 is formed so as to straddle the steel plate 1A via the circumferential groove G1, as shown in Fig. 5. This eliminates minute air gaps in the stator, enhancing the anchor effect described in Fig. 2, and substantially improving the adhesion between the steel plate 1A and the resin material 4, and therefore the adhesion between the stator core 1 and the housing 2, thereby improving heat dissipation when the coil generates heat. Note that it is more desirable to arrange the circumferential grooves G1 at equal intervals in the axial direction of the housing 2 in order to ensure uniform adhesion between the stator core 1 and the housing 2.

[0022] Third Embodiment 6 is a view showing a housing in a third embodiment of the stator. The illustrated housing 2 has grooves arranged on its inner circumferential surface in the shrink-fit range of the stator core 1. The grooves in the illustrated example are axial grooves G2 that are continuous in the axial direction of the housing 2 (the vertical direction in FIG. 6), and the axial grooves G2 are arranged at predetermined intervals in the circumferential direction of the housing 2.

[0023] The stator including the housing 2 described above can obtain the same effects as the second embodiment, and by employing the axial groove G2 that is continuous in the axial direction of the housing 2, the resin material 4 is formed in a state where it is connected in the circumferential direction of the housing 2 via the circumferential groove G2. This eliminates minute air gaps in the stator, and the anchor effect substantially improves the adhesion between the stator core 1 and the resin material 4, and therefore the adhesion between the stator core 1 and the housing 2, which in turn contributes to improving heat dissipation when the coil generates heat.

[0024] <Fourth embodiment> Fig. 7 is a diagram showing a housing in a fourth embodiment of the stator. The illustrated housing 2 has grooves arranged on its inner peripheral surface in the shrink-fit range of the stator core 1. The grooves in the illustrated example are circumferential grooves G1 that are continuous in the circumferential direction of the housing 2 and axial grooves G2 that are continuous in the axial direction of the housing 2 (the up-and-down direction in Fig. 7). The circumferential grooves G1 are arranged at predetermined intervals in the axial direction of the housing 2. The axial grooves G2 are also arranged at predetermined intervals in the circumferential direction of the housing 2.

[0025] The stator equipped with the above-described housing 2 can obtain the same effects as the first embodiment, and in addition, by adopting both the circumferential groove G1 and the axial groove G2, it combines the effects of both the second and third embodiments, suppressing peeling of the resin when the housing 2 is pressed in, eliminating minute air gaps, and substantially improving the adhesion between the stator core 1 and the housing 2 due to the anchor effect, thereby achieving further improvement in heat dissipation when the coil generates heat.

[0026] Fifth Embodiment 8 is a view showing a housing according to a fifth embodiment of the stator. The illustrated housing 2 has a groove disposed on its inner circumferential surface in the shrink-fit area of ​​the stator core 1. The illustrated groove is at least one spiral groove G3 that is continuous in the circumferential and axial directions of the housing 2 (the up-and-down direction in FIG. 8).

[0027] A stator including the housing 2 described above can obtain the same effects as those of the above-described embodiments, and by employing the spiral groove G3, the spiral groove G3 can be processed in a so-called single stroke, thereby realizing a reduction in manufacturing time and man-hours, etc. Note that, although this embodiment illustrates the case where one spiral groove G3 is formed, multiple spiral grooves G3 may be formed depending on the heat removal performance, the process capability for the outer diameter of the steel sheet 1A, and it is of course also possible to select the interval between the spiral grooves G3.

[0028] The configuration of the stator according to the present invention is not limited to the above-described embodiments, and can be modified as appropriate within the scope of the present invention, and the configurations of the above-described embodiments can also be combined. [Explanation of symbols]

[0029] 1 stator core 1A steel plate 2. Housing 4. Resin material G1 circumferential groove (groove) G2 Axis groove (groove) G3 Spiral groove (groove) S stator

Claims

1. A stator comprising a cylindrical stator core made of laminated steel plates and a cylindrical housing shrink-fitted to the outer periphery of the stator core, A stator comprising a resin material that fills a gap between the stator core and the housing.

2. 2. The stator according to claim 1, wherein a groove is disposed in an inner peripheral surface of the housing in a region where the stator core is shrink-fitted.

3. 3. The stator according to claim 2, wherein the grooves are circumferential grooves that are continuous in the circumferential direction of the housing, and the circumferential grooves are arranged at predetermined intervals in the axial direction of the housing.

4. 3. The stator according to claim 2, wherein the grooves are axial grooves that are continuous in the axial direction of the housing, and the axial grooves are arranged at predetermined intervals in the circumferential direction of the housing.

5. 3. The stator according to claim 2, wherein the grooves are circumferential grooves arranged at predetermined intervals in the circumferential direction of the housing, and axial grooves arranged at predetermined intervals in the circumferential direction of the housing.

6. 3. The stator according to claim 2, wherein the groove is at least one spiral groove that is continuous in the circumferential direction and the axial direction of the housing.

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