JP2019161766A - Electromagnetic steel sheet - Google Patents

Abstract

To provide an electromagnetic steel sheet by which a motor core can be stably manufactured even when applying a processing method generally used for manufacturing the motor core to the electromagnetic steel sheet in which an alloy addition amount is increased from a viewpoint of improving an iron loss.SOLUTION: An electromagnetic steel sheet is formed by bonding faces of two or more kinds of electromagnetic steel sheets that are different from each other. One of two or more kinds of the electromagnetic steel sheets has growth rate of 7% or less. Also the electromagnetic steel sheet with growth rate of 9% or more is adjacent to the electromagnetic steel with growth rate of 7% or less, and 20% or more of contact surface of the electromagnetic steel sheet is bonded.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an electrical steel sheet formed by bonding two or more different types of electrical steel sheets to each other.

  In recent years, in order to obtain a low iron loss electromagnetic steel sheet, a high frequency low iron loss electromagnetic steel sheet having a Si content of 6% or more has been developed. In such an electromagnetic steel sheet, since the Si content is high, the hardness is high and the brittleness, it is difficult to perform punching and caulking used in normal motor iron core manufacturing. In particular, in the caulking process, it is necessary to greatly deform the electromagnetic steel sheet locally, so it is difficult to process the low workability electromagnetic steel sheet. For this reason, conventionally, when manufacturing a motor core using a magnetic steel sheet having high hardness and low workability, the steel sheets are laminated after performing punching, wire cutting, and laser cutting. A method in which an adhesive is infiltrated and bonded between the electromagnetic steel sheets (see Patent Document 1), or a coating on the surface of the electromagnetic steel sheet has an adhesion function and is fixed after processing the iron core shape (see Patent Document 2). It was taken.

JP 2012-120299 A JP-A-4-299039

  However, in the method for manufacturing the motor core described above, the manufacturing process becomes complicated and the cost increases. For this reason, provision of the manufacturing method of the motor core using the conventional punching process and crimping process excellent in productivity was anticipated. Although it is becoming clear that machining of electrical steel sheets with higher hardness and lower elongation is possible by precisely controlling the conditions of punching and caulking, electrical steel sheets with an increased amount of alloy elements are becoming clearer. In the case of processing or when trying to secure productivity by increasing the processing speed, stable processing becomes difficult.

  The present invention has been made in view of the above-mentioned problems, and its purpose is to apply a processing method normally used in the manufacture of a motor core to an electromagnetic steel sheet having a high alloy addition amount from the viewpoint of iron loss improvement. Even in such a case, an electromagnetic steel sheet capable of stably producing a motor iron core is provided.

  The electrical steel sheet according to the present invention is an electrical steel sheet formed by bonding surfaces of two or more different types of electrical steel sheets to each other, and one of the two or more electrical steel sheets is elongated. Is a steel sheet of 7% or less, and an electrical steel sheet having an elongation of 7% or less is adjacent to an electrical steel sheet having an elongation of 9% or more, and 20% or more of the contact surface of the electrical steel sheet is bonded. It is characterized by that.

The electrical steel sheet according to the present invention is characterized in that, in the above invention, an insulating film having an interlayer resistance of 0.7 Ω · cm ² or more is formed on one side or both sides of adjacent electrical steel sheets that serve as adhesive surfaces between the electrical steel sheets. And

  According to the electromagnetic steel sheet according to the present invention, a motor iron core is stably produced even when a processing method normally used in the production of a motor iron core is applied to an electromagnetic steel sheet with a high alloy addition amount from the viewpoint of iron loss improvement. be able to.

FIG. 1 is a plan view showing a configuration of a stator iron core. FIG. 2 is a schematic diagram for explaining an adhesive surface of a steel plate.

  The inventors of the present invention have a method of performing caulking processing used in the manufacture of motor cores using an electromagnetic steel sheet having an Si content that has been inferior in terms of workability but has been inferior in terms of workability but has been increased to 6% or more. Various studies were made. As a result, the inventors obtained the knowledge that it is effective to use an electromagnetic steel sheet having a low Si content on an electromagnetic steel sheet having a Si content of 6% or more, and arrived at the present invention. Here, the reason that the caulking process is possible despite the use of the electromagnetic steel sheet having low workability by such a method is that the low Si content electromagnetic steel sheet having low hardness and large elongation is bonded. This is considered to be because the electrical steel sheet having a low Si content suppresses the fracture of the electrical steel sheet having a high Si content. Moreover, such knowledge can be arranged not only by the difference in Si content but by hardness and elongation which are indexes of workability.

  Hereinafter, the electrical steel sheet according to the present invention will be described.

(1) Use of a plurality of types of electrical steel sheets In the present invention, a plurality of different types (two or more types) of electrical steel sheets are mixed and used (mixed lamination) in the same motor core, whereby a low iron loss electrical steel sheet. The iron loss of the entire motor core tends to be inferior compared with the case where only is used. However, the inventors of the present invention have confirmed that in the case of a mixed laminated motor iron core, the characteristics of the magnetic steel sheet having high magnetic permeability are preferentially developed. The electrical steel sheet laminated with adhesive is advantageous in terms of the balance of magnetic properties and material cost. Furthermore, the workability of the material can be greatly improved by bonding a plurality of types of electrical steel sheets.

(2) One of a plurality of types of electrical steel sheets is an electrical steel sheet having an elongation of 7% or less, and an electrical steel sheet having an elongation of 7% or less is adjacent to an electrical steel sheet having an elongation of 9% or more. It is possible to greatly improve the workability of the entire electromagnetic steel sheet by adhering and bonding the magnetic steel sheet having high workability to the electromagnetic steel sheet having low workability. In many cases, it is suitable to evaluate the workability of the electrical steel sheet by the elongation. For improving the workability of the electrical steel sheet having a small elongation, it is effective to bond the electrical steel sheet having a large elongation. In addition, it is difficult to set a typical hardness in an electromagnetic steel sheet in which the Si content is distributed in a gradient direction in the thickness direction, but it can be specified in the case of elongation. The elongation here is preferably the average value in the rolling direction and the direction orthogonal to the rolling direction. When the elongation of the electrical steel sheet used exceeds 7%, it is not necessary to use the present invention because it can be processed normally by itself. Moreover, the workability of the whole bonded electrical steel sheet can be improved by setting the elongation of the electrical steel sheet to be bonded to the electrical steel sheet having an elongation of 7% or less to 9% or more.

(3) 20% or more of the contact surfaces are bonded. It is generally not clear at the manufacturing stage which portion of the base steel plate corresponds to the strongly processed portion by stamping or caulking. Therefore, the base steel plates to be laminated and bonded need to be bonded to each other in as wide a range as possible. However, even if the entire region is not completely bonded, a corresponding effect can be exhibited if a portion close to the processed portion is fixed to some extent. If the area of the bonded portion of the contact surface is less than 20%, the effect of the adjacent highly workable electrical steel sheet cannot be sufficiently imparted, so the range is limited to 20% or more. Further, from the results shown in Table 2 of Example 1, it is more desirable that the adhesion area ratio is 50% or more.

  In addition, it is possible to suppress an increase in eddy current by electrically insulating the joint surface where different types of electrical steel sheets are bonded and bonded, but insulate them before bonding to the part that becomes the joint surface of the magnetic steel sheet that is the base material. Even if the coating is not formed, if the adhesive layer such as an adhesive has an effect of sufficiently suppressing the insulation between the joined electrical steel sheets, the electrical contact between the laminated electrical steel sheets Increase in iron loss can be suppressed.

(4) In order to suppress an increase in eddy current due to electrical contact between the joint surfaces of different types of electrical steel sheets having an insulating film with an interlayer resistance of 0.7 Ω · cm ² or more on one or both sides of the bonding surface, It is desirable to have an insulating film having sufficient insulation on one side or both sides of the surface to be the bonding surface of the magnetic steel sheets to be bonded. Even in the absence of such an insulating coating, an insulating adhesive can also serve as an insulating layer, but when the thickness of the adhesive layer is insufficiently managed, partial electrical contact May occur and the magnetic characteristics may deteriorate. From such a viewpoint, it is ideal that one side or both sides of the surfaces of the magnetic steel sheets to be bonded and bonded have an insulating film in advance. At this time, in order to ensure the insulating property of the insulating coating, the interlayer resistance according to the method defined in JIS C 2550-4 is preferably 0.7 Ω · cm ² or more. If the interlayer resistance is less than 0.7 Ω · cm ² , an eddy current flows between different types of electrical steel sheets and the iron loss characteristics deteriorate, so that the resistance is limited to 0.7 Ω · cm ² or more.

  In obtaining the effects of the present invention, the method for bonding the magnetic steel sheets is not particularly limited, and various adhesives and adhesive coatings can be used. When an electromagnetic steel sheet having no insulating coating is used as the laminated steel sheet, it is necessary to select a non-conductive substance as an adhesive that also serves as an insulating layer. In addition, the idea of the present invention is obtained by trying to improve the workability of the electrical steel sheet having a high Si content, but the electrical steel sheet used is not limited to the electrical steel sheet having a high Si content, Although it is added in a large amount from the viewpoint of improving magnetic properties, such as a high Cr content electrical steel sheet and a high Al content electrical steel sheet, it is applicable when elements that deteriorate the workability of the electrical steel sheet are added.

[Example 1]
In this example, 1-3 types of electrical steel sheets shown in Table 1 were laminated in the order shown in Table 1 and adhered to each other. The bonding method was an epoxy adhesive or an adhesive film. When bonded with an epoxy-based adhesive, do not form an insulating coating on the bonding surface of the base steel sheet, but also serve as an insulating layer in the adhesive layer after bonding, and the outer side of the magnetic steel sheet after being laminated and bonded An insulating coating made of a chromic acid compound and an organic resin was formed on the surface (Nos. 3 and 7). Moreover, in the examples of Nos. 4 to 6, adhesion was performed by forming an adhesive film on the surface to be the bonding surface of the base steel plate and holding it at 700 ° C. for 5 minutes in a pressurized state. An insulating coating made of a chromic acid compound and an organic resin was formed on the outer surface of the magnetic steel sheet after being laminated and adhered. In any case, the area ratio of the bonded portion in the entire electromagnetic steel sheet was 20 to 50%. Using these steel plates, stamping and crimping of the stator core 1 shown in FIG. 1 was performed using a progressive die. Here, the clearance at the time of punching was 8% of the total thickness of the laminated steel sheets. Further, the caulking 2 was V caulking, the long side when the V caulking portion was viewed from above was 3 mm, the short side was 1 mm, and the height of the caulking dowel was 0.4 mm. The state after the press working with the progressive die was observed. The case where a clear crack was observed at the punching end was indicated as “X”, the case where a very small crack was observed as “Δ”, and the case where there was no problem at all. For caulking, the case where the crack occurrence rate at the dowel was 50% or more was evaluated as x, the case where the crack generation rate was 5 to 50% was Δ, and the case where the crack generation rate was 5% or less was rated as ◯.

  Table 1 shows the results of pressing. As shown in Table 1, it can be said that the problem is sufficiently suppressed in both the punching process and the caulking process under the condition that satisfies the condition of claim 1 of the present invention. Moreover, using the magnetic steel sheet of No. 5 in Table 1 in Table 2, by changing the application area of the adhesive variously, the adhesive area ratio and workability (press workability, The caulking property is shown. Sufficient workability was ensured when the adhesion area ratio was 20% or more, and more desirable results were obtained if 50% or more were adhered.

[Example 2]
In this example, the two types of original steel plates used in numbers 4 and 8 shown in Table 1 have various thicknesses on the surfaces of FIG. 2 (the original steel plate 1 lower surface and the original steel plate 2 upper surface) to be bonded. An insulating film made of a chromic acid compound and an organic resin was formed, and then bonded and integrated using an epoxy adhesive. The adhesion area ratio at this time was 50 to 70%. The interlayer resistance value of each surface before adhesive bonding was measured according to JIS C 2550-4. When the punch test of the stator iron core 1 shown in FIG. 1 was performed from the obtained electromagnetic steel sheet, both the punching process and the caulking process could be carried out without any problem. Further, an Epstein test piece having a length of 280 mm and a width of 30 mm in the rolling direction and the direction perpendicular to the rolling direction was cut out from the laminated and bonded steel plates, and the iron loss W10 / 400 was measured by the method defined in JIS C 2550-3. Table 3 shows the relationship between the interlayer resistance value of each surface and the magnetic properties of the laminated steel sheets. As shown in Table 3, iron loss can be reduced by forming an insulating film having an interlayer resistance of 0.7 Ω · cm ² or more on one surface of the lower surface of the original steel plate 1 and the upper surface of the original steel plate 2 and then bonding the steel plates together. It was confirmed that the increase was suppressed.

  The embodiment to which the invention made by the present inventors is applied has been described above, but the present invention is not limited by the description and the drawings that constitute a part of the disclosure of the present invention. That is, other embodiments, examples, operational techniques, and the like made by those skilled in the art based on this embodiment are all included in the scope of the present invention.

1 Stator core 2 Caulking

Claims (2)

It is an electrical steel sheet formed by bonding the surfaces of two or more different electrical steel sheets to each other,
One of the two or more types of electrical steel sheet is a steel sheet having an elongation of 7% or less, and further, an electrical steel sheet having an elongation of 9% or more is adjacent to the electrical steel sheet having an elongation of 7% or less, and An electrical steel sheet, wherein 20% or more of the contact surface of the electrical steel sheet is bonded. 2. The electrical steel sheet according to claim 1, wherein an insulating coating having an interlayer resistance of 0.7 Ω · cm ² or more is formed on one surface or both surfaces of adjacent electrical steel sheets serving as bonding surfaces between the electrical steel sheets.

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