Stator core and method for manufacturing a stator core

Abstract

The objective is to provide a stator core that can prevent a decrease in the efficiency of suppressing iron loss due to deformation, even when stress is applied to the stator core. [Solution] A stator core (1) constructed by laminating multiple metal sheets (10), wherein the multiple metal sheets are made of a soft magnetic amorphous alloy, and the stator core has a protrusion (11) provided on the outer periphery (14) of the stator core to relieve the press-fit stress into the stator core, the protrusion being made of resin.

Description

Technical Field

[0001] The present invention relates to a motor stator core and a method for manufacturing a stator core.

Background Art

[0002] As a performance generally required for a motor stator core, low iron loss (loss) is one of the requirements, and a soft magnetic amorphous alloy is known as a soft magnetic material with extremely low iron loss (see, for example, Patent Document 1, for example).

Prior Art Literature

Patent Literature

[0003]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0004] However, when a stator core formed of a soft magnetic amorphous alloy is fitted into a stator cover, if stress is applied to the stator core side, the stressed portion may be denatured, which reduces the iron loss suppression efficiency in some cases.

[0005] An object of the present invention is to provide a stator core and a method for manufacturing a stator core that can prevent a reduction in iron loss suppression efficiency caused by denaturation even when stress is applied to the stator core.

Means for Solving the Problem

[0006] The stator core according to the present invention is configured by laminating a plurality of metal sheets, wherein the plurality of metal sheets are formed of a soft magnetic amorphous alloy, the stator core has a convex portion provided on an outer peripheral portion of the stator core for alleviating press-fitting stress applied to the stator core, and the convex portion is formed of resin.

[0007] In the stator core according to the present invention, it is preferable that the multiple metal sheets are bonded together with an adhesive, and the protrusions are formed by the adhesive extruded onto the outer circumference of the stator core.

[0008] In the stator core according to the present invention, it is preferable that the protrusion of the convex portion is 0.03 mm or more and 1% or less of the diameter of the stator core.

[0009] In the stator core according to the present invention, it is preferable that multiple protrusions are arranged at equal intervals on the outer circumference of the stator core.

[0010] In the method for manufacturing a stator core according to the present invention, multiple metal sheets are laminated while being bonded together with an adhesive, and a portion of the adhesive extruded from between the multiple metal sheets during lamination is solidified to form a protrusion, and the multiple metal sheets are made of a soft magnetic amorphous alloy. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a stator core and a method for manufacturing a stator core that can prevent a decrease in the efficiency of suppressing iron loss due to deformation, even when stress is applied to the stator core. [Brief explanation of the drawing]

[0012] [Figure 1] (a) is a schematic perspective view of the stator core 1 according to the present invention, and (b) is a top view of the stator core 1. [Figure 2] This is a conceptual diagram of a manufacturing apparatus 100 for producing a stator core 1. [Figure 3] (a) is a top view of another stator core 2, and (b) is a top view of yet another stator core 3. [Figure 4] (a) is a diagram showing a stator core 40 without a protrusion, and (b) is a diagram showing the stator core 1 shown in Figure 1. [Modes for carrying out the invention]

[0013] Hereinafter, an embodiment of the stator core and a method for manufacturing the stator core will be described with reference to the drawings. However, it should be noted that the technical scope of the present invention is not limited to these embodiments, but extends to the invention described in the claims and its equivalents.

[0014] Figure 1(a) is a perspective view of the stator core 1 according to the present invention, and Figure 1(b) is a top view of the stator core 1. The stator core 1 is constructed by laminating a plurality of ultra-thin metal plates 10, each of which is composed of a yoke 12 and teeth 13, and six vertically elongated resin protrusions 11 are arranged on the outer periphery 14.

[0015] Figure 1(b)A shows a magnified view of the area around the protrusion 11. In the stator core 1 shown in Figure 1, the protrusion amount of the protrusion 11 is s1 mm, and the width of the protrusion 11 is s2 mm. The protrusion amount (s1) of the protrusion 11 is preferably 0.03 mm or more, and 1% or less of the diameter R mm of the stator core 1. The reason for setting the protrusion amount of the protrusion 11 as described above is that if it is less than 0.03 mm, the effect of substantially absorbing stress is not obtained, and if it is greater than 1% of the diameter R mm of the stator core 1, it takes up too much space. In addition, the width (s2) of the protrusion 11 is preferably 0.03 mm or more, and may be provided around the entire circumference. The reason for setting the width of the protrusion 11 as described above is that if it is less than 0.03 mm, the effect of substantially absorbing stress is not obtained.

[0016] Motor iron losses include hysteresis loss, which is caused by magnetic hysteresis in the motor's magnetic material and results in heat within the magnetic material, and eddy current loss, which is caused by eddy currents generated by electromagnetic induction when a magnetic field passes through the steel plate, resulting in Joule heat within the steel plate. By using a soft magnetic amorphous alloy, hysteresis loss in the stator core is reduced, and by using an ultrathin metal plate, eddy current loss is reduced. Therefore, the ultrathin metal plate 10 in the stator core 1 is made of a soft magnetic amorphous alloy and has a thickness of approximately 0.015 mm to 0.05 mm.

[0017] FIG. 2 is a conceptual diagram of a manufacturing apparatus 100 for manufacturing a stator core 1. The manufacturing apparatus 100 includes a cylindrical portion 101 for laminating ultra-thin metal plates 10, and six groove portions 102 disposed on an outer peripheral portion of the cylindrical portion 101.

[0018] FIG. 2 illustrates a state where one more ultra-thin metal plate 10 is further laminated on a laminated body 1′ in which a plurality of ultra-thin metal plates 10 have already been laminated. In the method for manufacturing a stator core 1 according to the present invention, an adhesive lamination method is employed in which the respective ultra-thin metal plates 10 are adhered by an adhesive to form a laminated body.

[0019] From the state shown in FIG. 2, an adhesive is disposed between one ultra-thin metal plate 10 and the laminated body 1′, and the ultra-thin metal plate 10 is pressed from above in the drawing to be fixed onto the laminated body 1′. This process is repeated to complete the stator core 1 shown in FIG. 1. Although the number of sheets to be laminated varies depending on factors such as the size of the motor, hundreds to thousands of ultra-thin metal plates 10 are laminated to complete the stator core 1.

[0020] Further, the amount of the adhesive is adjusted, and the ultra-thin metal plates 10 are pressed such that the adhesive discharged to the outer peripheral portion 14 from between adjacent ultra-thin metal plates 10 enters the groove portions 102. When the above process is repeated and a predetermined number of ultra-thin metal plates 10 are laminated after a predetermined drying process and the like, the stator core 1 in which the convex portions 11 are formed along the groove portions 102 on the outer peripheral portion 14 is completed. As the adhesive, epoxy resin, polyimide resin, or silicone resin adhesives can be used; any thermosetting adhesive that can penetrate into a gap of about 1 μm and has insulating properties can be used.

[0021] FIG. 3(a) is a top view of another stator core 2, and FIG. 3(b) is a top view of still another stator core 3.

[0022] In the stator core 2 shown in Fig. 3(a), twelve protrusions 21 are arranged at equal intervals along the outer periphery of the stator core 2 (outside the yoke 22) at the positions of the teeth 23. Further, in the stator core 3 shown in Fig. 3(b), twelve protrusions 31 are arranged at equal intervals along the outer periphery of the stator core 3 at positions between adjacent teeth 33 and 33.

[0023] In the stator core 1 shown in Fig. 1, six vertically elongated protrusions 11 are arranged at equal intervals along the outer periphery 14 of the stator core 1 at the positions of the teeth 13. However, as shown in Figs. 3(a) and 3(b), the number of protrusions 11, 21, 31 is not limited to six, and other numbers may be employed. The protrusions may be arranged at the positions of the teeth 13, or at positions other than the positions of the teeth.

[0024] Fig. 4 is a diagram for explaining the function of the protrusions, wherein (a) shows a stator core 40 having no protrusions, and (b) shows the stator core 1 shown in Fig. 1. It is assumed that the stator core 40 has the same configuration as the stator core 1 except that it does not have the protrusions 11.

[0025] As shown in Fig. 4(a), in the case of the stator core 40 having no protrusions, when the stator core 40 is press-fitted into the stator core cover 50 during the motor manufacturing process, a part of the outer periphery of the stator core 40 may be pressed by the stator core cover 50 and deformed. A soft magnetic amorphous alloy is an amorphous material with a random, irregular atomic arrangement. For this reason, soft magnetic amorphous alloys have no magnetocrystalline anisotropy, and the movement of magnetic domains during the magnetization process is easy, so the hysteresis loss is lower than that of ordinary metallic materials. However, when stress is applied to a part of the material, the amorphous property of the stressed portion is disrupted, which reduces the suppression efficiency of hysteresis loss in the entire stator core 40.

[0026] On the other hand, as shown in Figure 4(b), in the case of a stator core 1 having protrusions 11, multiple protrusions 11 are arranged on the outer circumference 14 of the stator core 1. Therefore, when the stator core 1 is press-fitted into the stator core cover 50, the resin protrusions 11 act as a buffer, reducing the stress applied to a part of the outer circumference of the stator core 1. Consequently, the amorphous nature of the stator core 1 is not disrupted, and the hysteresis loss suppression efficiency is maintained as originally intended.

[0027] (modified version) The protrusions 11 of the stator core 1 are made of resin and are formed by the solidification of adhesive that has squeezed out from between multiple ultra-thin metal plates 10 through the manufacturing process shown in Figure 2. Therefore, the protrusions 11 are not formed on each ultra-thin metal plate 10. However, the stator core according to the present invention may be manufactured without following the manufacturing method shown in Figure 2. For example, a stator core without protrusions 11 may be completed by laminating multiple ultra-thin metal plates 10, and then the protrusions 11 may be placed on the outer periphery 14 of the stator core to complete the stator core 1. In this case, the protrusions 11 may be simply bonded to the outer periphery of the stator core, or a predetermined groove may be formed in advance on the outer periphery 14 of the stator core, and the protrusions 11 may be fitted into the groove to form the protrusions 11.

[0028] Alternatively, minute protrusions may be pre-formed on each of the ultra-thin metal plates 10, and the stator core 1 may be completed by stacking the ultra-thin metal plates 10 with the protrusions already formed on them.

[0029] In the stator cores 1, 2, and 3 described above, the protrusions are located in the same position when viewed from above. However, the positions of the protrusions located on the lower outer circumference of the stator core may differ from those located on the middle section and / or upper outer circumference of the stator core. Furthermore, the number of protrusions located on the lower outer circumference of the stator core may differ from the number of protrusions located on the middle section and / or upper outer circumference of the stator core.

[0030] For example, a soft magnetic amorphous alloy has a composition in which, when the total amount of Fe, Si, and B is taken as 100 atomic%, Si is 0 atomic% to 10 atomic%, B is 10 atomic% to 20 atomic%, and Fe accounts for the remainder. Other elements such as Mn, S, C, and Al may be included as additives or unavoidable impurities. A soft magnetic amorphous alloy preferably has the above composition and is amorphous (non-crystalline) without a crystalline structure. The amount of Si is preferably 3 atomic% to 10 atomic%, and more preferably 3 atomic% to 7 atomic%. The amount of B is preferably 10 atomic% to 15 atomic%, and more preferably 13 atomic% to 15 atomic%. Furthermore, in order to obtain a high B80, the amount of Fe is preferably 78 atomic% or more, more preferably 79.5 atomic% or more, more preferably 80 atomic% or more, and more preferably 81 atomic% or more. Soft magnetic amorphous alloys may contain additives or unavoidable impurities, but the total proportion of Fe, Si, and B is preferably 95% by mass or more, and more preferably 98% by mass or more. Furthermore, less than 50% of the Fe atoms may be substituted with Co or Ni. Fe-based amorphous alloys are manufactured by ultra-rapid casting and are non-crystalline materials with an irregular, random atomic arrangement. Because they lack crystal timing anisotropy, the movement of magnetic domains during the magnetization process is easy, resulting in low hysteresis loss when used in applications where the direction of magnetic flux changes periodically, such as motors and transformers. Additionally, obtaining non-crystalline materials by ultra-rapid casting limits the material thickness to approximately 15 μm to 50 μm. This thinness reduces eddy current loss when used as a core material, and combined with the aforementioned properties, it is known as a material with low iron loss.

[0031] Those skilled in the art will understand that various changes, substitutions, and modifications can be made without departing from the spirit and scope of the present invention. For example, the embodiments and modifications described above may be combined as appropriate within the scope of the invention. [Explanation of Symbols]

[0032] 1, 2, 3 Stator Cores 10 Ultra-thin metal plate 11, 21, 31 Convex parts

Claims

1. A stator core constructed by laminating multiple metal sheets, The aforementioned plurality of metal sheets are composed of a soft magnetic amorphous alloy. The stator core has a protrusion provided on its outer circumference to relieve the press-fit stress into the stator core, The aforementioned protrusion is made of resin. A stator core characterized by the following features.

2. The aforementioned multiple metal sheets are bonded together with an adhesive, The aforementioned protrusion is formed by adhesive material extruded onto the outer circumference of the stator core. The stator core according to claim 1.

3. The stator core according to claim 1, wherein the discharge amount of the protrusion is 0.03 mm or more and 1% or less of the diameter of the stator core.

4. The stator core according to any one of claims 1 to 3, wherein the protrusions are arranged at equal intervals on the outer circumference of the stator core.

5. Multiple metal sheets are laminated together using adhesive, During lamination, some of the adhesive extruded from between the multiple metal sheets is solidified to form a protrusion. The aforementioned plurality of metal sheets are composed of a soft magnetic amorphous alloy. A method for manufacturing a stator core, characterized by the following:

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