WO2021260906A1

WO2021260906A1 - Laminated steel sheet and rotor of rotation electrical machine

Info

Publication number: WO2021260906A1
Application number: PCT/JP2020/025136
Authority: WO
Inventors: 幸嗣上山; 芳幸加茂; 護寺井; 亮人岩▲崎▼
Original assignee: 三菱電機株式会社
Priority date: 2020-06-26
Filing date: 2020-06-26
Publication date: 2021-12-30
Also published as: JPWO2021260906A1

Abstract

The present invention provides a laminated steel sheet which can achieve high heat resistance at 150℃ or more and high stiffness such as to be bearable with high speed rotations at the same time.　Provided is a laminated steel sheet (10) acquired by bonding a plurality of laminated electromagnetic steel sheets (1) with a bonding layer. The bonding layer is configured by a first bonding agent (4) disposed so as to be separated and a second bonding agent (6) disposed so as to fill an area of a gap in the first bonding agent. In the bonding layer viewed in a direction which makes a right angle with a lamination direction, an area occupancy of the first bonding agent is 10% to 90% (both inclusive).

Description

Laminated steel plate and rotor of rotary electric machine

This application relates to laminated steel sheets and rotors of rotary electric machines.

The stator of the rotary electric machine, the iron core of the rotor, the iron core of the transformer, etc. are composed of laminated steel plates on which electromagnetic steel plates are laminated. Methods for joining laminated electrical steel sheets include caulking, welding, and joining with an adhesive. Adhesive if the thickness of the electrical steel sheet is as thin as 0.3 mm or less, if the material of the electrical steel sheet is a material that is not easily plastically deformed such as silicon steel sheet, or if the eddy current loss generated in the electrical steel sheet is a problem. The method of joining electrical steel sheets using the above is the most advantageous.

As a method for manufacturing a laminated steel sheet using an adhesive, a method is known in which a laminated electromagnetic steel sheet is placed in a vacuum container and an adhesive is impregnated between the laminated electromagnetic steel sheets in a vacuum exhaust (for example). See Patent Document 1). As another method, a method of laminating electromagnetic steel sheets to which an adhesive film is attached and pressure-bonding them is known (see, for example, Patent Document 2).

Japanese Unexamined Patent Publication No. 2004-08870 Japanese Patent No. 6589172

With the miniaturization and higher output of the rotary electric machine, the rotor of the rotary electric machine is rotated at a high speed of 10,000 rpm or more. Therefore, the temperature of the rotor core may be 150 ° C. or higher. In addition, a strong centrifugal force is applied to the rotor core that rotates at high speed. Therefore, the laminated steel sheet used for the rotor core is required to have high heat resistance and toughness. In the conventional laminated steel sheets bonded with an adhesive, there is only one type of adhesive for joining the electromagnetic steel sheets to each other. None of the adhesives can simultaneously satisfy the high heat resistance required for a rotor core having a temperature of 150 ° C. or higher and the toughness that can withstand high-speed rotation. Therefore, the laminated steel sheet joined with the conventional adhesive has a problem that high heat resistance of 150 ° C. or higher and toughness capable of withstanding high-speed rotation cannot be achieved at the same time.

The present application has been made to solve the above-mentioned problems, and an object thereof is to provide a laminated steel sheet capable of achieving both high heat resistance of 150 ° C. or higher and toughness capable of withstanding high-speed rotation.

In the laminated steel sheet of the present application, a plurality of laminated electromagnetic steel sheets are bonded by an adhesive layer. The adhesive layer is composed of a first adhesive arranged separately and a second adhesive arranged so as to fill a region between the first adhesives, and is perpendicular to the stacking direction. In the adhesive layer viewed from the direction, the area occupancy of the first adhesive is 10% or more and 90% or less.

The laminated steel plate of the present application is composed of a first adhesive in which adhesive layers are discretely arranged and a second adhesive in which the adhesive layers are arranged so as to fill a region between the first adhesives. The area occupancy of the first adhesive is 10% or more and 90% or less in the adhesive layer viewed from the direction perpendicular to. Therefore, the laminated steel sheet of the present application can achieve both high heat resistance of 150 ° C. or higher and toughness capable of withstanding high-speed rotation.

It is external drawing of the electromagnetic steel sheet which concerns on Embodiment 1. FIG. It is explanatory drawing of the method of forming an adhesive layer which concerns on Embodiment 1. FIG. It is explanatory drawing of the method of forming an adhesive layer which concerns on Embodiment 1. FIG. It is explanatory drawing of the manufacturing method of the laminated steel sheet of Example 1 of Embodiment 1. FIG. It is explanatory drawing of the manufacturing method of the laminated steel sheet of Example 5 of Embodiment 1. FIG. It is explanatory drawing of the manufacturing method of the laminated steel sheet of Example 6 of Embodiment 1. FIG. It is explanatory drawing of the manufacturing method of the laminated steel sheet of Example 7 of Embodiment 1. FIG. It is explanatory drawing of the manufacturing method of the laminated steel sheet of the comparative example 1 of Embodiment 1. FIG. It is explanatory drawing of the manufacturing method of the laminated steel sheet of the comparative example 2 of Embodiment 1. FIG. It is a block diagram of the adhesive layer of the comparative example 3 of Embodiment 1. FIG. It is a block diagram of the adhesive layer of the comparative example 4 of Embodiment 1. FIG. It is explanatory drawing of the rotation test in Embodiment 1. It is explanatory drawing of the drop test in Embodiment 1. FIG. It is a figure which shows the characteristic table of the Example and the comparative example in Embodiment 1. FIG.

Hereinafter, the laminated steel sheet according to the embodiment for carrying out the present application will be described in detail with reference to the drawings. In each figure, the same reference numerals indicate the same or corresponding parts.

Embodiment 1.
FIG. 1 is an external view of an electromagnetic steel sheet used for the laminated steel sheet according to the first embodiment. The laminated steel sheet of this embodiment is applied to a rotor core of a rotary electric machine. As shown in FIG. 1, the electrical steel sheet 1 of the present embodiment is circular, and has a central hole 2 for penetrating a shaft in the center and a plurality of slots 3 for inserting a permanent magnet into an outer edge portion. Has been done. The laminated steel sheet on which the electromagnetic steel sheet 1 is laminated is used for a rotor core of an embedded magnet type synchronous rotary electric machine (IPM: Interior Permanent Magnet). When the laminated steel plate is used for the rotor core of a surface magnet type synchronous rotary electric machine (SPM: Surface Permanent Magnet), the slot 3 is not formed in the electromagnetic steel plate 1.

2 and 3 are explanatory views of a method for forming an adhesive layer according to the present embodiment. Hereinafter, the method for forming the adhesive layer shown in FIG. 2 will be referred to as a first forming method, and the method for forming the adhesive layer shown in FIG. 3 will be referred to as a second forming method. Next, a method of forming each adhesive layer will be described.

<First forming method>
As shown in FIG. 2A, the first adhesive 4 is applied to one surface of the electrical steel sheet 1. The first adhesive 4 is discretely applied to the surface of the electromagnetic steel sheet 1. As a method of applying the first adhesive 4, for example, a dispenser can be used. Next, as shown in FIG. 2B, the electrical steel sheet 1 is laminated and pressed to form a laminated adhesive 5. At this time, the coating area of the first adhesive 4 is expanded in the plane direction, but a gap is formed between the first adhesives 4. Next, as shown in FIG. 2C, the second adhesive 6 is impregnated into the gap formed between the first adhesives 4 of the laminated adhesive 5. As the impregnation method of the second adhesive 6, for example, a vacuum impregnation method in which a liquid is impregnated using a vacuum state can be used. Finally, in this laminated adhesive body 5, the adhesive is cured to become a laminated steel plate 10.

<Second formation method>
As shown in FIG. 3A, the first adhesive 4 and the second adhesive 6 are applied to one surface of the electrical steel sheet 1. The first adhesive 4 and the second adhesive 6 are separately applied to the surface of the electromagnetic steel sheet 1. As a method of applying the first adhesive 4 and the second adhesive 6, for example, a dispenser can be used. Next, as shown in FIG. 3B, the electrical steel sheet 1 is laminated and pressed to form a laminated adhesive 5. At this time, the coating areas of the first adhesive 4 and the second adhesive 6 are expanded in the plane direction. When the coating areas of the first adhesive 4 and the second adhesive 6 are expanded in the plane direction, the first adhesive 4 and the second adhesive 6 are separated into their respective coating regions without being completely mixed. Depending on the amount of the adhesive applied, there are cases where a gap is formed between the application area of the first adhesive 4 and the application area of the second adhesive 6, and there are cases where the gap is not formed. Finally, in this laminated adhesive body 5, the adhesive is cured to become a laminated steel plate 10.

In the first forming method, the first adhesive 4 is applied to one surface of the electrical steel sheet 1, but it may be applied to both surfaces. Further, in the second forming method, the first adhesive 4 and the second adhesive 6 are applied to the same surface of the electromagnetic steel sheet 1, but they may be applied to different surfaces. In the first forming method and the second forming method, the adhesive protruding from the central hole 2 and the slot 3 of the electrical steel sheet 1 is removed.

Next, an example and a comparative example in the laminated steel sheet of this embodiment will be described.
<Example 1>
As an electromagnetic steel sheet having the shape shown in FIG. 1, a non-oriented silicon steel sheet having a diameter of 140 mm and a thickness of 0.25 mm was prepared. Further, a room temperature curable modified acrylic adhesive was prepared as the first adhesive, and a low-viscosity acrylic adhesive was prepared as the second adhesive. The viscosity and thixophilicity of the first adhesive are such that they do not flow by themselves when spread under pressure. The viscosity of the second adhesive is about 100 mPa · s that can be impregnated into the laminated adhesive. The first forming method was adopted as the method for forming the adhesive layer. FIG. 4 is a partially enlarged view for explaining the method for manufacturing the laminated steel sheet of the first embodiment. As shown in FIG. 4A, the surface of the electrical steel sheet 1 was first degreased and washed with isopropyl alcohol. Next, as shown in FIG. 4B, the first adhesive 4 was applied in an oval shape with a dispenser. Next, 260 sheets of electrical steel sheets 1 were laminated and pressed to obtain a laminated adhesive. FIG. 4C shows a state in which the coating area of the first adhesive 4 is expanded on the surface of the laminated pressed electromagnetic steel sheet 1. In this state, the first adhesive was cured at room temperature. Next, the second adhesive 6 was impregnated into the gap formed between the first adhesives 4 of the laminated adhesive. FIG. 4D shows a state in which the second adhesive 6 is impregnated in the gap formed between the first adhesives 4 on the surface of the laminated pressed electromagnetic steel sheet 1. Finally, the laminated adhesive was heated at 130 ° C. for 60 minutes to complete the laminated steel sheet of Example 1. The thickness of the completed laminated steel sheet is about 65 mm.

<Example 2>
As an electromagnetic steel sheet having the shape shown in FIG. 1, a non-oriented silicon steel sheet having a diameter of 140 mm and a thickness of 0.1 mm was prepared. Further, a room temperature curable modified acrylic adhesive was prepared as the first adhesive, and a low-viscosity acrylic adhesive was prepared as the second adhesive. The first adhesive and the second adhesive are the same as the first adhesive and the second adhesive of Example 1, respectively. The first forming method was adopted as the method for forming the adhesive layer. Further, the partially enlarged view for explaining the manufacturing method of the laminated steel plate of the second embodiment is the same as that of FIG. First, the surface of the electrical steel sheet 1 was degreased and washed with isopropyl alcohol, and further subjected to atmospheric pressure plasma treatment. Next, the first adhesive 4 was applied in an oval shape with a dispenser. Next, 650 sheets of electrical steel sheets 1 were laminated and pressed to obtain a laminated adhesive. In this state, the first adhesive was cured at room temperature. Next, the second adhesive 6 was impregnated into the gap formed between the first adhesives 4 of the laminated adhesive. Finally, the laminated adhesive was heated at 130 ° C. for 60 minutes to complete the laminated steel sheet of Example 2. The thickness of the completed laminated steel sheet is about 65 mm.

<Example 3>
As an electromagnetic steel sheet having the shape shown in FIG. 1, a non-oriented silicon steel sheet having a diameter of 140 mm and a thickness of 0.35 mm was prepared. Further, a room temperature curable modified acrylic adhesive was prepared as the first adhesive, and a low-viscosity acrylic adhesive was prepared as the second adhesive. The first adhesive and the second adhesive are the same as the first adhesive and the second adhesive of Example 1, respectively. The first forming method was adopted as the method for forming the adhesive layer. Further, the partially enlarged view for explaining the manufacturing method of the laminated steel sheet of the third embodiment is the same as that of FIG. First, the surface of the electrical steel sheet 1 was laser-cleaned. Next, the first adhesive 4 was applied in an oval shape with a dispenser. Next, 185 sheets of electrical steel sheets 1 were laminated and pressed to obtain a laminated adhesive. In this state, the first adhesive was cured at room temperature. Next, the second adhesive 6 was impregnated into the gap formed between the first adhesives 4 of the laminated adhesive. Finally, the laminated adhesive was heated at 130 ° C. for 60 minutes to complete the laminated steel sheet of Example 3. The thickness of the completed laminated steel sheet is about 65 mm.

<Example 4>
As an electromagnetic steel sheet having the shape shown in FIG. 1, a non-directional permendur having a diameter of 140 mm and a thickness of 0.25 mm was prepared. Permendur is a one-to-one alloy of iron and cobalt. Further, a heat-curable one-component type amine-cured epoxy adhesive was prepared as the first adhesive, and a low-viscosity acrylic adhesive was prepared as the second adhesive. The viscosity and thixophilicity of the first adhesive are such that they do not flow by themselves when spread under pressure. The second adhesive is the same as the second adhesive of Example 1. The first forming method was adopted as the method for forming the adhesive layer. Further, the partially enlarged view for explaining the manufacturing method of the laminated steel plate of the fourth embodiment is the same as that of FIG. First, the surface of the electrical steel sheet 1 was degreased and washed with isopropyl alcohol. Next, the first adhesive 4 was applied in an oval shape with a dispenser. Next, 260 sheets of electrical steel sheets 1 were laminated and pressed to obtain a laminated adhesive. In this state, the first adhesive was heated at 140 ° C. for 60 minutes to cure. After cooling the laminated adhesive, the gap formed between the first adhesives 4 of the laminated adhesive was impregnated with the second adhesive 6. Finally, the laminated adhesive was heated at 130 ° C. for 60 minutes to complete the laminated steel sheet of Example 4. The thickness of the completed laminated steel sheet is about 65 mm.

<Example 5>
As an electromagnetic steel sheet having the shape shown in FIG. 1, a non-oriented silicon steel sheet having a diameter of 140 mm and a thickness of 0.25 mm was prepared. Further, a room temperature curable modified acrylic adhesive was prepared as the first adhesive, and a low-viscosity acrylic adhesive was prepared as the second adhesive. The first adhesive and the second adhesive are the same as the first adhesive and the second adhesive of Example 1, respectively. The first forming method was adopted as the method for forming the adhesive layer. FIG. 5 is a partially enlarged view for explaining the method for manufacturing the laminated steel sheet of Example 5. As shown in FIG. 5A, the surface of the electrical steel sheet 1 was first degreased and washed with isopropyl alcohol. Next, as shown in FIG. 5B, the first adhesive 4 was applied in an oval shape with a dispenser. Next, 260 sheets of electrical steel sheets 1 were laminated and pressed to obtain a laminated adhesive. FIG. 5C shows a state in which the coating area of the first adhesive 4 is expanded on the surface of the laminated pressed electromagnetic steel sheet 1. In this state, before the first adhesive was cured, the gap formed between the first adhesives 4 of the laminated adhesive was impregnated with the second adhesive 6. Finally, the laminated adhesive was heated at 130 ° C. for 60 minutes to complete the laminated steel sheet of Example 5. The thickness of the completed laminated steel sheet is about 65 mm. FIG. 5D shows an adhesive layer on the surface of the electrical steel sheet 1 in the completed laminated steel sheet. The adhesive layer of the laminated steel sheet of Example 5 is composed of a region of the first adhesive 4, a region of the second adhesive 6, and a mixed region 7 in which the first adhesive 4 and the second adhesive 6 are mixed. It had been.

<Example 6>
As an electromagnetic steel sheet having the shape shown in FIG. 1, a non-oriented silicon steel sheet having a diameter of 140 mm and a thickness of 0.25 mm was prepared. Further, a room temperature curable modified acrylic adhesive was prepared as the first adhesive, and a heat-curable one-component amine-curable epoxy adhesive was prepared as the second adhesive. The first adhesive is the same as the first adhesive of Example 1, and the second adhesive is the same as the first adhesive of Example 4. The second forming method was adopted as the method for forming the adhesive layer. FIG. 6 is a partially enlarged view for explaining the method for manufacturing the laminated steel sheet of Example 6. As shown in FIG. 6A, the surface of the electrical steel sheet 1 was first degreased and washed with isopropyl alcohol. Next, as shown in FIG. 6B, the first adhesive 4 and the second adhesive 6 were applied in an elliptical shape with a dispenser, respectively. The amount of the first adhesive 4 and the second adhesive 6 applied was about 5 times the amount of the first adhesive applied in Example 1. The first adhesive 4 and the second adhesive 6 were arranged alternately. Next, 260 sheets of electrical steel sheets 1 were laminated and pressed to obtain a laminated adhesive. This laminated adhesive was heated at 140 ° C. for 60 minutes to complete the laminated steel sheet of Example 6. The thickness of the completed laminated steel sheet is about 65 mm. FIG. 6C shows an adhesive layer on the surface of the electrical steel sheet 1 in the completed laminated steel sheet. The adhesive layer of the laminated steel sheet of Example 6 is composed of a region of the first adhesive 4, a region of the second adhesive 6, and a mixed region 7 in which the first adhesive 4 and the second adhesive 6 are mixed. It had been.

<Example 7>
As an electromagnetic steel sheet having the shape shown in FIG. 1, a non-oriented silicon steel sheet having a diameter of 140 mm and a thickness of 0.25 mm was prepared. In addition, a room temperature curable modified acrylic adhesive is used as the first adhesive, a heat-curable one-component amine-curable epoxy adhesive is used as the second adhesive, and a low-viscosity acrylic adhesive is used as the third adhesive. Got ready. The first adhesive and the third adhesive are the same as the first adhesive and the second adhesive of Example 1, respectively, and the second adhesive is the same as the first adhesive of Example 4. The first forming method was adopted as the method for forming the adhesive layer. However, the adhesives applied in an oval shape with the dispenser are the first adhesive and the second adhesive. FIG. 7 is a partially enlarged view for explaining the method for manufacturing the laminated steel sheet of Example 7. As shown in FIG. 7A, the surface of the electrical steel sheet 1 was first degreased and washed with isopropyl alcohol. Next, as shown in FIG. 7B, the first adhesive 4 and the second adhesive 6 were applied in an elliptical shape with a dispenser, respectively. The coating amount of the first adhesive 4 and the second adhesive 6 was set to about 1/5 of the coating amount of the first adhesive in Example 6. The first adhesive 4 and the second adhesive 6 were arranged alternately. Next, 260 sheets of electrical steel sheets 1 were laminated and pressed to obtain a laminated adhesive. FIG. 7C shows a state in which the coated areas of the first adhesive 4 and the second adhesive 6 are expanded on the surface of the laminated pressed electromagnetic steel sheet 1. In Example 7, a gap was formed between the first adhesive 4 and the second adhesive 6. In this state, the first adhesive and the second adhesive 6 were heated at 150 ° C. for 60 minutes to be cured. After cooling the laminated adhesive, the gap formed between the first adhesive 4 and the second adhesive 6 was impregnated with the third adhesive 8. FIG. 7D shows a state in which the third adhesive 8 is impregnated in the gap formed between the first adhesive 4 and the second adhesive 6 on the surface of the laminated pressed electromagnetic steel sheet 1. Finally, the laminated adhesive was heated at 140 ° C. for 60 minutes to complete the laminated steel sheet of Example 7. The thickness of the completed laminated steel sheet is about 65 mm.

<Comparative Example 1>
As an electromagnetic steel sheet having the shape shown in FIG. 1, a non-oriented silicon steel sheet having a diameter of 140 mm and a thickness of 0.25 mm was prepared. Further, as the first adhesive, a heat-curable one-component type amine-cured epoxy adhesive was prepared. The first adhesive is the same as the first adhesive of Example 4. The second forming method was adopted as the method for forming the adhesive layer. However, only the first adhesive was applied to almost the entire surface of the magnetic steel sheet with a dispenser. FIG. 8 is a partially enlarged view for explaining the method for manufacturing the laminated steel sheet of Comparative Example 1. As shown in FIG. 8A, the surface of the electrical steel sheet 1 was first degreased and washed with isopropyl alcohol. Next, as shown in FIG. 8B, the first adhesive 4 was applied to the surface of the electrical steel sheet 1 in an elliptical shape with a dispenser. Next, 260 sheets of electrical steel sheets 1 were laminated and pressed to obtain a laminated adhesive. FIG. 8C shows a state in which the first adhesive 4 covers the entire surface of the laminated pressed electromagnetic steel sheet 1. Finally, the laminated adhesive was heated at 140 ° C. for 60 minutes to complete the laminated steel sheet of Comparative Example 1. The thickness of the completed laminated steel sheet is about 65 mm.

<Comparative Example 2>
As an electromagnetic steel sheet having the shape shown in FIG. 1, a non-oriented silicon steel sheet having a diameter of 140 mm and a thickness of 0.25 mm was prepared. Further, a heat-curable one-component type amine-cured epoxy adhesive was prepared as the first adhesive, and a low-viscosity acrylic adhesive was prepared as the second adhesive. The first adhesive and the second adhesive are the same as the first adhesive and the second adhesive of Example 4, respectively. The first forming method was adopted as the method for forming the adhesive layer. However, the first adhesive was applied to half of the surface of the electrical steel sheet with a dispenser. FIG. 9 is a partially enlarged view for explaining a method for manufacturing a laminated steel sheet of Comparative Example 2. As shown in FIG. 9A, the surface of the electrical steel sheet 1 was first degreased and washed with isopropyl alcohol. Next, as shown in FIG. 9B, the first adhesive 4 was applied in an elliptical shape to the lower half of the surface of the electrical steel sheet 1 with a dispenser. In the partially enlarged view shown in FIG. 9, the lower half corresponds to a semicircle of a circular electrical steel sheet. Next, 260 sheets of electrical steel sheets 1 were laminated and pressed to obtain a laminated adhesive. FIG. 9C shows a state in which the first adhesive 4 covers the lower half of the surface of the laminated pressed electromagnetic steel sheet 1. In this state, the first adhesive 4 was cured at room temperature. Next, the second adhesive 6 was impregnated in the upper half region of the laminated pressed electromagnetic steel sheet 1 to which the first adhesive 4 was not applied. FIG. 9D shows a state in which the upper half of the surface of the laminated pressed electromagnetic steel sheet 1 is impregnated with the second adhesive 6. Finally, the laminated adhesive was heated at 130 ° C. for 60 minutes to complete the laminated steel sheet of Comparative Example 2. The thickness of the completed laminated steel sheet is about 65 mm.

<Comparative Example 3>
The manufacturing method and the adhesive of the laminated steel sheet of Comparative Example 3 are the same as those of Example 6. However, the amount of the first adhesive 4 and the second adhesive 6 applied in an elliptical shape with the dispenser was set to about 1/10 of the amount of the first adhesive applied in Example 6. Therefore, in the completed laminated steel sheet, the structure of the adhesive layer is different from that of Example 6. FIG. 10 shows the structure of the adhesive layer of Comparative Example 3. As shown in FIG. 10, in the adhesive layer of Comparative Example 3, the first adhesive 4 and the second adhesive 6 cover only a part of the surface of the electrical steel sheet 1, and a part of the surface of the electrical steel sheet 1 is exposed. is doing.

<Comparative Example 4>
The method for manufacturing the laminated steel sheet of Comparative Example 4 is the same as that of Example 6. However, the adhesive used is only the first adhesive of Example 6, and the amount of the first adhesive 4 applied in an elliptical shape with the dispenser is the amount of the first adhesive applied in Example 6. It was set to about 1/10. Therefore, in the completed laminated steel sheet, the structure of the adhesive layer is different from that of Example 6. FIG. 11 shows the structure of the adhesive layer of Comparative Example 4. As shown in FIG. 11, in the adhesive layer of Comparative Example 4, the first adhesive 4 covers only a part of the surface of the electrical steel sheet 1, and a part of the surface of the electrical steel sheet 1 is exposed.

Next, the evaluation method of the laminated steel sheet will be described. The evaluation items are the area occupancy of the first adhesive, the elastic modulus of the first adhesive, the thickness of the adhesive layer, and the peeling evaluation of the adhesive layer after the durability test.

<Area occupancy rate of the first adhesive>
The laminated steel sheet was forcibly peeled off, and an image of the adhesive layer viewed from a direction perpendicular to the laminating direction was obtained using an image processing device. Then, the ratio of the area occupied by the first adhesive to the total area of the adhesive layer was calculated by the image processing apparatus. As a result, the area occupancy of the first adhesive in the laminated steel sheets of Examples 1, 2, 3, 4, 5, 6 and 7 was 27%, 66%, 36%, 33%, 27% and 50%, respectively. And 24%. The area occupancy of the first adhesive in the laminated steel sheets of Comparative Examples 1, 2, 3 and 4 was 100%, 45%, 4% and 27%, respectively.

<Elastic modulus of the first adhesive>
The elastic modulus of the adhesive referred to here is the elastic modulus in a state where the adhesive is solidified in the adhesive layer when the laminated steel sheet is formed.
The laminated steel sheet was forcibly peeled off, and the elastic modulus of the first adhesive was measured. A nano indenter (manufactured by Elionix Inc.) was used to measure the elastic modulus. The elastic modulus was calculated from the measurement results when the temperature of the first adhesive was maintained at 160 ° C. and measured up to 259 steps at 20 msec per step with a pressure of 2 mN using a Berkovich indenter. As a result, the elastic moduli of the first adhesive of the laminated steel sheets of Examples 1, 2, 3, 4, 5, 6 and 7 at 160 ° C. were 0.3 GPa, 0.3 GPa, 0.3 GPa and 1.5 GPa, respectively. , 0.3 GPa, 1.5 GPa and 0.3 GPa. The elastic moduli of the first adhesive of the laminated steel sheets of Comparative Examples 1, 2, 3 and 4 at 160 ° C. were 1.5 GPa, 1.5 GPa, 0.3 GPa and 0.3 GPa, respectively.

<Thickness of adhesive layer>
The thickness of one layer of the adhesive layer was calculated by dividing the thickness of all the electromagnetic steel sheets from the total thickness of the laminated steel sheets. As a result, the thicknesses of the adhesive layers in the laminated steel sheets of Examples 1, 2, 3, 4, 5, 6 and 7 were 2 μm, 1.5 μm, 4 μm, 3 μm, 3 μm, 2 μm and 3 μm, respectively. The thicknesses of the adhesive layers in the laminated steel sheets of Comparative Examples 1, 2, 3 and 4 were 3 μm, 4 μm, 2 μm and 3 μm, respectively.

<Evaluation of peeling of adhesive layer after durability test>
First, the durability test method will be described. The durability test is a test that combines a thermal cycle test, a rotation test, and a drop test.
After holding the laminated steel sheet at 200 ° C. for 200 hours, a thermal cycle test was performed in which holding at 180 ° C. for 10 minutes and holding at −55 ° C. for 10 minutes were repeated 50 times. Next, a rotation test was performed. FIG. 12 is an explanatory diagram showing a rotation test method. As shown in FIG. 12, the shaft 11 was attached to the laminated steel plate 10 by shrink fitting, and the shaft 11 was connected to the rotary machine 12. Then, the rotary machine 12 was rotated at 10000 rpm for 2 hours. During the rotation, hot air was blown onto the laminated steel sheet 10 using a heat gun 13, and the surface temperature of the laminated steel sheet 10 was maintained in the range of 180 ° C. to 200 ° C. Finally, a drop test was conducted. FIG. 13 is an explanatory diagram showing a drop test method. The laminated steel plate 10 removed from the rotary machine was cooled to room temperature, and the laminated steel plate 10 was dropped from a height of 20 cm onto the concrete block 14 with the shaft 11 facing down five times in a row.

Next, the evaluation of peeling of the adhesive layer after such a durability test will be described. This peeling evaluation was performed on three laminated steel sheets in each of the examples and the comparative examples.
Evaluation 1: The entire outer circumference of the laminated steel sheet was visually observed, and whether or not the peeling of the adhesive layer could be confirmed was used as a criterion. If peeling can be confirmed, it is regarded as a defective product, and if peeling cannot be confirmed, it is regarded as a good product.
Evaluation 2: The entire outer circumference of the laminated steel sheet was observed with a magnifying glass having a magnification of 10 times, and whether or not peeling of the adhesive layer could be confirmed was used as a criterion. If peeling can be confirmed, it is regarded as a defective product, and if peeling cannot be confirmed, it is regarded as a good product.

FIG. 14 is a characteristic table showing the types of adhesives, types of electrical steel sheets, methods for forming adhesive layers, evaluation results, etc. in the laminated steel sheets of Examples and Comparative Examples. Regarding the notation of evaluation 1 and evaluation 2 in FIG. 14, the denominator represents the number of laminated steel sheets subjected to the durability test, and the numerator represents the number of defective products. For example, when two of the three laminated steel sheets subjected to the durability test are defective, it is described as 2/3. In Evaluation 1 and Evaluation 2 after the durability test, when all three laminated steel sheets are good products, the laminated steel sheets can have both high heat resistance of 150 ° C. or higher and toughness that can withstand high-speed rotation. It was judged. In

evaluations

1 and 2 after the durability test, if even one defective product was included, it was judged that the laminated steel sheet could not achieve both high heat resistance of 150 ° C. or higher and toughness capable of withstanding high-speed rotation.

No defective products were confirmed in the laminated steel sheets of Examples 1 to 7 in Evaluation 1 and Evaluation 2 after the durability test. From this, a laminated steel sheet having an adhesive layer composed of a first adhesive arranged separately and a second adhesive arranged so as to fill a region between the first adhesives is 150. It can be seen that both high heat resistance of ℃ or higher and toughness that can withstand high-speed rotation can be achieved.
Further, from the results of Examples 1, 2 and 3, it can be seen that the same effect can be obtained when the thickness of the electrical steel sheet is in the range of 0.1 mm to 0.35 mm. Further, it can be seen that the same effect can be obtained regardless of whether the surface cleaning treatment method of the electrical steel sheet is the degreasing cleaning treatment, the atmospheric pressure plasma treatment, or the laser cleaning treatment.
Further, from the results of Example 4, it can be seen that the same effect can be obtained not only when the electromagnetic steel sheet is a silicon steel sheet but also when the permendur is an iron-chromium alloy.
Further, from the results of Example 5, it can be seen that the same effect can be obtained even when there is a region where the first adhesive and the second adhesive coexist between the first adhesive and the second adhesive.
Further, from the results of Example 6, the method of arranging the second adhesive so as to fill the region between the first adhesives arranged separately is not limited to the method of impregnation, but may be a method of coating. You can see that.
Furthermore, from the results of Example 7, it can be seen that the same effect can be obtained even when the first adhesives arranged separately are composed of two types of adhesives.

Therefore, the laminated steel sheet in which the electromagnetic steel sheet is laminated with the adhesive layer in which the second adhesive is arranged so as to fill the region between the first adhesives arranged separately has a high heat resistance of 150 ° C. or higher. It can achieve both toughness that can withstand high-speed rotation. In other words, it can be said that the first adhesives are arranged separately at a plurality of places, or the first adhesives are arranged discontinuously. ..

The reason why the laminated steel sheet configured in this way can achieve both high heat resistance of 150 ° C or higher and toughness that can withstand high-speed rotation is presumed as follows. Once a crack occurs in the adhesive layer, the crack may propagate to the surroundings in a short time. However, if the propagation of this crack can be suppressed, it will not lead to a large fracture of the adhesive layer. The effect of suppressing the propagation of this crack is called the crack arrest effect. In the adhesive layer of the present embodiment, since the second adhesive is arranged so as to fill the region between the first adhesives arranged separately, the first adhesive and the second adhesive can be separated from each other. It is considered that the crack arrest effect is exhibited at the contacting part. As a result, it is presumed that the laminated steel sheet of the present embodiment can have both high heat resistance of 150 ° C. or higher and toughness capable of withstanding high-speed rotation.

On the other hand, in the laminated steel sheets of Comparative Examples 1 to 4, one or more defective products were confirmed in the evaluation 1 and the evaluation 2 after the durability test.
From the results of Comparative Example 1, it can be seen that a laminated steel sheet having an adhesive layer whose entire surface is composed of only one type of adhesive cannot achieve both high heat resistance of 150 ° C. or higher and toughness capable of withstanding high-speed rotation. It is considered that the above-mentioned crack arrest effect does not appear in the adhesive layer whose entire surface is composed of only one type of adhesive.
Further, from the results of Comparative Example 2, a laminated steel sheet having an adhesive layer composed of two types of adhesives on each half surface cannot achieve both high heat resistance of 150 ° C. or higher and toughness capable of withstanding high-speed rotation. I understand. It is considered that the above-mentioned crack arrest effect does not appear in the region occupied by the respective adhesives in the adhesive layer composed of two types of adhesives on each half side.
Further, from the results of Comparative Examples 3 and 4, a laminated steel sheet having an adhesive layer in which one or two types of adhesives are discretely arranged and a part of the surface of the electromagnetic steel sheet is exposed has a high heat resistance of 150 ° C. or higher. It can be seen that it is not possible to achieve both the toughness that can withstand high-speed rotation. In the laminated steel sheet of Comparative Example 3, the second adhesive is arranged in the region between the first adhesives arranged separately. However, in the laminated steel sheet of Comparative Example 3, since the second adhesive does not fill the region between the first adhesives, high heat resistance and toughness cannot be achieved at the same time. That is, it is considered that the above-mentioned crack arrest effect does not appear in Comparative Examples 3 and 4 because there is no portion where the adhesives come into contact with each other.

Next, each configuration in the laminated steel sheet of this embodiment will be described.
<Electromagnetic steel sheet>
The electromagnetic steel sheet suitable for the laminated steel sheet of the present embodiment may be any soft magnetic material applicable to the iron core of a rotary electric machine. Non-directional silicon steel sheets were used in Examples 1 to 3, and non-directional permendur was used in Example 4. From the viewpoint of practicality, the electromagnetic steel sheet is preferably made of cast iron, silicon steel sheet, iron-chromium alloy such as permendur, or amorphous magnetic material (amorphous magnetic material). These electromagnetic steel sheets may be non-oriented electrical steel sheets or may be grain-oriented electrical steel sheets. Further, two or more kinds of electromagnetic steel sheets may be used in combination for adjusting the magnetic characteristics of the laminated steel sheets.
The thickness of the electrical steel sheet is preferably in the range of 0.02 mm to 0.5 mm, and more preferably in the range of 0.1 mm to 0.35 mm from the viewpoint of practicality and productivity.
The surface state of the electrical steel sheet may be any state as long as the reliability of adhesion can be ensured. Generally, electrical steel sheets are coated for the purpose of insulation and corrosion protection. From the viewpoint of availability, a silicon steel sheet coated with a silicone system is one of the desirable electromagnetic steel sheets.

<Surface cleaning method for electrical steel sheets>
Normally, electrical steel sheets are thinly adhered with press oil for processing, rust preventive oil for rust prevention, and the like. In order to remove these oils and improve the adhesiveness of the adhesive, it is desirable to perform surface cleaning treatment of the electrical steel sheet. As the surface cleaning treatment method, degreasing cleaning treatment with solvent system such as isopropyl alcohol, degreasing cleaning treatment with water system, ultraviolet irradiation treatment, atmospheric pressure plasma treatment, plasma treatment under reduced pressure, laser cleaning treatment, flame radiation treatment, coupling Examples thereof include a combined treatment of an agent and flame radiation, a chemical etching treatment, an acid cleaning treatment, an alkali cleaning treatment, a chromium acid-based chemical conversion treatment, a phosphoric acid-based chemical conversion treatment, a zirconium-based chemical conversion treatment, a silane coupling treatment, and a titanate treatment. As a specific surface cleaning treatment method, degreasing cleaning was adopted in Examples 1, 4, 5, 6 and 7, atmospheric pressure plasma treatment was adopted in Example 2, and laser cleaning treatment was adopted in Example 3. As another surface cleaning treatment method, a mechanical surface cleaning treatment method such as shot blasting or sanding may be applied as long as it does not affect the magnetic properties of the electrical steel sheet. From the viewpoint of the simplicity of the manufacturing process, the solvent-based degreasing cleaning treatment, the water-based degreasing cleaning treatment, or the atmospheric pressure plasma treatment is suitable as the surface cleaning treatment method for the electrical steel sheet.

<Elastic modulus of the first adhesive>
In this embodiment, two or more kinds of adhesives are used. It is desirable that at least one of these adhesives has an elastic modulus of 0.1 GPa or more at 160 ° C. Further, it is more desirable that the elastic modulus of this adhesive has an elastic modulus of 0.2 GPa or more at 160 ° C. When the elastic modulus of the adhesive is 0.1 GPa or more at 160 ° C., the rigidity of the adhesive layer is high, and it is possible to obtain toughness that can withstand high-speed rotation.
The elastic modulus of the adhesive depends on the elastic modulus of the resin which is the main component of the adhesive and the amount of the inorganic fine particles dispersed in the resin. The elastic modulus of the adhesive increases as the amount of the inorganic fine particles added increases. On the other hand, if the amount of the inorganic fine particles added is too large, the toughness of the adhesive is impaired. Therefore, the upper limit of the elastic modulus of the adhesive is about 10 GPa from the viewpoint of the toughness of the adhesive layer. The elastic modulus of the adhesive is preferably 5 GPa or less, and more preferably 2.5 GPa or less.

<Material of the first adhesive>
As the first adhesive, epoxy-based, acrylic-based, polyimide-based, amidimide-based, and phenol-based adhesives can be used. The type of the adhesive may be a one-component type or a mixed type of two or more solutions. The curing type of the adhesive may be any of a room temperature curing type, a heat curing type, an anaerobic curing type, an ultraviolet curing type, and a moisture curing type.
The adhesive may contain a diluent solvent. The adhesive containing a diluting solvent may be of a type in which the diluting solvent volatilizes when it is cured, or may be a type in which the diluting solvent does not volatilize when it is cured. Further, the adhesive may contain a primer, a curing accelerator and the like.

<Method of applying the first adhesive>
As the method of applying the first adhesive, any method may be used as long as the adhesive can be applied discretely. For example, as a method of applying an adhesive, a dispenser that extrudes a fixed amount of liquid material from the tip of a nozzle and attaches it to an object to be coated, a jet dispenser that injects a fixed amount of liquid material from the tip of a nozzle and attaches it to an object to be coated, and the like. Can be mentioned. Further, as another coating method, a transfer method using a transfer pin, a transfer roller, or the like can also be used.

<Elastic modulus of the second adhesive>
The elastic modulus of the second adhesive may be lower than the elastic modulus of the first adhesive. For example, the elastic modulus of the second adhesive may be about 1 MPa, or may be about 0.1 GPa, which is equivalent to the elastic modulus of the first adhesive.

<Material for the second adhesive>
As the second adhesive, adhesives such as epoxy-based, acrylic-based, polyimide-based, amidoimide-based, phenol-based, urethane-based, silane-modified polymer-based, silicone-based, and synthetic rubber-based adhesives can be used. The curing type of the adhesive may be any of a room temperature curing type, a heat curing type, an anaerobic curing type, an ultraviolet curing type, and a moisture curing type.

Specifically, the following materials can be used as the materials for the first adhesive and the second adhesive.
As one-component type epoxy adhesives, Nagase Chemtex's Denatite (registered trademark) series, 3M's Scotchweld (registered trademark) series, HENKEL's LOCTILE HYSOL (registered trademark) series, and ThreeBond Co., Ltd. 2200 series manufactured by Nisshinbo Chemical Co., Ltd., Carbodilite (registered trademark) series manufactured by Nisshinbo Chemical Co., Ltd., EP series manufactured by Cemedine Co., Ltd., and the like can be used.
As acrylic adhesives, Denka's Hard Lock (registered trademark) series, Cemedine's Metal Lock (registered trademark) series, High Pressure Gas Industry's Pega Lock (registered trademark) series, and PERMABOND's TA series. , LORD's Maxlok (registered trademark) series, 3M's Scotchweld (registered trademark) DP series, HENKEL's LOCTEL (registered trademark) series, ITW's PLEXUS (registered trademark) series, etc. Can be done.
As the low-viscosity acrylic adhesive used for impregnation coating, AS series manufactured by ASEC, Vistex (registered trademark) manufactured by Matsumoto Fine Chemicals, and the like can be used. As the low-viscosity epoxy adhesive, a plain set (registered trademark) manufactured by Ajinomoto Fine-Techno Co., Ltd. can be used.

<Structure of adhesive layer>
The larger the volume ratio of the electromagnetic steel sheet to the volume of the laminated steel sheet, the better the magnetic characteristics as the rotor core. From this point of view, it is preferable that the thickness of the adhesive layer is thin. However, the thickness of the adhesive layer needs to be 0.1 μm or more from the viewpoint of ensuring the reliability of adhesion between the electromagnetic steel sheets. Specifically, the thickness of the adhesive layer is preferably 0.1 μm or more and 20 μm or less, and more preferably 0.5 μm or more and 5 μm or less.
The area occupancy of the first adhesives arranged separately needs to be 10% or more and 90% or less. When the area occupancy of the first adhesive is less than 10% or more than 90%, it resembles the structure of Comparative Example 1 in which the adhesive layer is composed of one kind of adhesive. In order to exert the crack arrest effect on the entire surface of the adhesive layer, it is necessary that the two types of adhesives are arranged over the entire surface in contact with each other. Therefore, the area occupancy of at least one of the two types of adhesive needs to be 10% or more. That is, in order to achieve both high heat resistance and toughness, it is necessary that the area occupancy of the first adhesives arranged separately is 10% or more and 90% or less. The area occupancy of the first adhesive is more preferably 20% or more and 80% or less, ideally 40% or more and 60% or less. The crack arrest effect becomes more pronounced as the difference between the area occupancy of the first adhesive and the area occupancy of the second adhesive becomes smaller.

<Operating temperature range>
The laminated steel sheet of the present embodiment has a heat resistance of class F (155 ° C.) in the heat resistance class of electrical equipment defined by JIS C4003: 2010 of Japanese Industrial Standards. The lower limit of the operating temperature region on the low temperature side is −40 ° C. when used in ground equipment and −60 ° C. when used in an aircraft.

The rotary electric machine provided with the rotor core made of the laminated steel plate of the present embodiment is used, for example, in automobiles, railroad vehicles, ships, aircraft, electric power equipment, and general industrial equipment.

Although the present application describes exemplary embodiments, the various features, embodiments, and functions described in the embodiments are not limited to the application of a particular embodiment, either alone or. Various combinations are applicable to the embodiments.
Therefore, innumerable variations not exemplified are envisioned within the scope of the techniques disclosed herein. For example, it is assumed that at least one component is modified, added or omitted.

1 electromagnetic steel plate, 2 center hole, 3 slot, 4 first adhesive, 5 laminated adhesive, 6 second adhesive, 7 mixed area, 8 third adhesive, 10 laminated steel plate, 11 shaft, 12 rotary machine, 13 Heat gun, 14 concrete blocks.

Claims

A laminated steel sheet in which a plurality of laminated electromagnetic steel sheets are bonded by an adhesive layer.
The adhesive layer is composed of a first adhesive arranged separately and a second adhesive arranged so as to fill a region between the first adhesives, and is perpendicular to the stacking direction. A laminated steel plate having an area occupancy of 10% or more and 90% or less of the first adhesive in the adhesive layer when viewed from a direction.
The laminated steel sheet according to claim 1, wherein the first adhesive has an elastic modulus of 0.1 GPa or more at 160 ° C.
A rotor of a rotary electric machine, characterized by having an iron core made of the laminated steel plate according to claim 1 or 2.