EA042110B1 - PLATED CORE AND ELECTRIC MOTOR - Google Patents

Description

The field of technology to which the invention belongs

The present invention relates to a laminated core and to an electric motor.

This patent application claims priority to Japanese Patent Application No. 2018-235857 filed December 17, 2018, the contents of which are incorporated herein by reference.

State of the art

Conventionally, a laminated core as described in Patent Document 1 below has been known. In this laminated core, electrical steel sheets adjacent to each other in the axial direction are bonded to each other.

List of bibliographic references

Patent Documents.

Patent document 1.

Unexamined patent application (Japan), first publication number 2011-023523.

The essence of the invention

Problems solved by the invention.

There is a margin to improve the magnetic properties of the traditional laminated core.

The present invention has been made in view of the above circumstances, and the purpose of the present invention is to improve the magnetic properties of the laminated core.

Problem solver.

(1) One aspect of the present invention is a laminated core including a plurality of electrical steel sheets stacked on top of each other, and adhesive portions that are provided between the electrical steel sheets next to each other in the axial direction and adhere the electrical steel sheets to each other. each of the electrical steel sheets includes an annular back portion of the core and a plurality of teeth that extend from the back portion of the core in the radial direction of the back portion of the core and are spaced in the circumferential direction of the back portion of the core, and each of the teeth of the electrical steel sheets includes a bonding area containing an adhesive portion in the form of a strip extending in the circumferential direction.

According to the above configuration, each of the teeth of the electrical steel sheets has a bonding area containing a strip-shaped adhesive portion. Since the strip-shaped adhesive portion extends in one direction, the bonding area of the adhesive portion can increase and improve its adhesive strength compared to the case in which the dotted adhesive portions are provided discontinuously in the same range.

A curing shrinkage tension of the adhesive material occurs in a region of each of the electrical steel sheets in contact with the adhesive portion, and steel loss of each of the electrical steel sheets increases in this region. Here, the area of each of the electrical steel sheets in which the steel loss increases due to the tension caused by contact with the bonding area is called a degradation area. According to the above configuration, since the adhesive portions are in the form of a strip extending in the circumferential direction and are provided on the teeth, the degrading area extends in the circumferential direction of the teeth. Since the magnetic flux flowing through the teeth is in the radial direction, the length of the magnetic flux path passing through the degrading region is reduced due to the degrading region extending in the circumferential direction. Therefore, the magnetic resistance to each magnetic flux in the magnetic circuit is reduced, and deterioration of the magnetic properties of the laminated core can be prevented.

(2) The laminated core according to the above (1) may have a configuration in which bonding areas are formed on the side closer to the back portion of the core than to the vicinity of the tooth tops.

The magnetic flux dissipates and passes from the tops of the teeth in both circumferential directions. For this reason, the magnetic flux tends to be concentrated in both circumferential end portions in the vicinity of the tops of the teeth. If a degradation region is provided in a region in which the magnetic flux is concentrated, the steel loss tends to increase significantly. For this reason, if a degradation region is provided in the vicinity of the tooth tips, the iron loss tends to increase. According to the above configuration, since the bonding areas are located on the side closer to the back portion of the core than to the vicinity of the tooth tops, the degraded area can be located at a large distance from the area having a high magnetic flux density, thereby preventing iron loss from increasing.

(3) The laminated core according to the above (1) or above (2) may have a configuration in which the width dimensions of the bonding areas in the radial direction increase from the circumferential tooth center portions to the sides of the circumferential tooth end portions.

The magnetic flux dissipates and passes from the tops of the teeth in both circumferential directions. In addition, the magnetic flux tends to flow over the shortest distance. For this reason, the magnetic flux density of the teeth increases towards the sides of the circumferential end portions. If the variation

- 1 042110 magnetic flux density of the teeth increases in the circumferential direction, the magnetic properties of the laminated core may deteriorate. According to the above configuration, the width dimensions of the bonding areas in the radial direction increase from the tooth center portions to the sides of the circumferential end portions. Thus, the length of the degradation region in the radial direction becomes longer from the tooth center portions to the sides of the circumferential end portions. For this reason, the magnetic resistance of the teeth increases toward the outside in the circumferential direction, and the magnetic flux does not easily flow on the sides of the circumferential end portions. As a result, variation in the magnetic flux density of the teeth can be prevented, and the magnetic flux density in the teeth can become uniform, thereby improving the magnetic properties of the laminated core.

(4) The laminated core according to (1) above or (2) above may have a configuration in which the bonding areas extend in arcuate shapes in the circumferential direction.

According to the above configuration, since the adhesive portions can be evenly applied in the circumferential direction, the manufacturing process can be simplified.

(5) The laminated core according to (1) to (4) above may have a configuration in which the adhesive portions extend over all tooth widths.

According to the above configuration, since the adhesive portions extend over all widths of the teeth, the adhesive strength between the teeth can be easily secured.

(6) In the laminated core according to any of the above (1) to (5), the average thickness of the adhesive portions may be 1.0 to 3.0 µm.

(7) In the laminated core according to any of the above (1) to (6), the average tensile modulus E of the adhesive portions may be 1500-4500 MPa.

(8) In the laminated core according to any of the above (1) to (7), the adhesive portions may be room temperature adhesive acrylic-based adhesives containing SGA made from an elastomer-containing acrylic-based adhesive.

(9) In the laminated core according to any of the above (1) to (8), the melting point of each of the adhesive portions may be 180° C. or higher.

(10) An electric motor according to one aspect of the present invention is an electric motor including a laminated core according to any of the above (1) to (9).

Since the motor having the above configuration has a laminated core having excellent magnetic properties, the power efficiency of the motor can be improved.

Benefits of the Invention

According to the present invention, the magnetic properties of the laminated core can be improved.

Brief description of the figures

Fig. 1 is a sectional view of an electric motor according to one embodiment of the present invention.

Fig. 2 is a plan view of a stator included in the motor shown in FIG. 1.

Fig. 3 is a front view of a stator included in the electric motor shown in FIG. 1.

Fig. 4 is a schematic view of the electrical steel sheet and bonding area of the stator shown in FIG. 2 and 3.

Fig. 5 is a schematic view of the stator bonding area of the modified example 1. FIG. 6 is a schematic view of the stator bonding area of the modified example 2. FIG. 7 is a schematic view of the stator bonding area of the modified example 3. FIG. 8 is a schematic view of the stator bonding area of the modified example 4. FIG. 9 is a schematic view of the stator bonding area of the modified example 5. FIG. 10 is a graph showing the results of steel loss simulation of models 1-4.

Fig. 11 is a schematic view of a model number 4 stator core as a comparative example.

Embodiments for carrying out the invention

Hereinafter, this document describes an electric motor according to one embodiment of the present invention with reference to the drawings. In addition, in the present embodiment, as a motor, a motor, namely, an AC motor, more specifically, a synchronous motor, and more specifically, a permanent magnet motor, is described as an example. This type of electric motor is suitably used for an electric vehicle, for example.

As shown in FIG. 1 and 2, the electric motor 10 includes a stator 20, a rotor 30, a casing 50, and a rotary shaft 60. The stator 20 and the rotor 30 are housed in the casing 50. The stator 20 is attached to the casing 50.

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In the electric motor 10 of the present embodiment, for example, a drive current having an effective value of 10 A and a frequency of 100 Hz is applied to each phase of the stator 20, and along with this, the rotor 30 and the rotation shaft 60 rotate at a rotation speed of 1000 rpm. min.

In the present embodiment, an internal rotor motor in which the rotor 30 is located in the stator 20 is used as the electric motor 10. However, an external rotor motor in which the rotor 30 is located outside the stator 20 can be used as the electric motor 10. Additionally , in the present embodiment, the motor 10 is a three-phase AC motor having 12 poles and 18 slots. However, for example, the number of poles, the number of slots, the number of phases, etc. can be changed appropriately.

The stator 20 includes a stator core 21 (laminated core) and windings (not shown).

The stator core 21 includes an annular back portion 22 and a plurality of teeth 23. The axial direction (direction of the central axis O of the stator core 21) of the stator core 21 (the back portion 22) is called the axial direction, the radial direction (the direction orthogonal to the central axis O of the stator core 21) of the stator core 21 (core back portion 22) is called the radial direction, and the circumferential direction (rotational direction about the central axis O of the stator core 21) of the stator core 21 (core back portion 22) is called the circumferential direction below.

The back portion 22 of the core has an annular shape when viewed from above the stator 20 when viewed from the axial direction.

A plurality of teeth 23 extend inwardly in the radial direction from the core back portion 22 (towards the central axis O of the core back portion 22 in the radial direction). A plurality of teeth 23 are arranged at equal intervals in the circumferential direction. In the present embodiment, 18 prongs 23 are provided every 20° of a central angle centered on the central axis O. A plurality of prongs 23 are formed to be identical in shape and size to each other.

The windings are wound around the teeth 23. The windings may be concentrated windings or distributed windings.

The rotor 30 is located in the stator 20 (stator core 21) in the radial direction. The rotor 30 includes a rotor core 31 and a plurality of permanent magnets 32.

The rotor core 31 is formed to have an annular shape (encircling the annular shape) disposed coaxially with the stator 20. The rotation shaft 60 is disposed in the rotor core 31. The rotation shaft 60 is attached to the core 31 of the rotor.

A plurality of permanent magnets 32 are attached to the rotor core 31. In the present embodiment, a set of two permanent magnets 32 form one magnetic pole. A plurality of sets of permanent magnets 32 are arranged at equal intervals in the circumferential direction. In the present embodiment, 12 sets (24 in total) of permanent magnets 32 are provided every 30° of a central angle centered on the central axis O.

In the present embodiment, an internal permanent magnet motor is used as a permanent magnet excited motor. A plurality of through holes 33 that extend through the rotor core 31 in the axial direction are formed in the rotor core 31 . The plurality of through holes 33 are provided so that they correspond to the plurality of permanent magnets 32. Each permanent magnet 32 is attached to the rotor core 31 in the state in which it is located in the corresponding through hole 33. The attachment of each permanent magnet 32 to the rotor core 31 can be implemented, for example, by providing an adhesive between the outer surface of the permanent magnet 32 and the inner surface of the through hole 33 with an adhesive material or the like. In addition, as a permanent magnet motor, a surface permanent magnet motor can be used instead of an internal permanent magnet motor.

Lined core.

As shown in FIG. 3, the stator core 21 is a laminated core. The stator core 21 is formed by laminating a plurality of electrical steel sheets 40 . Thus, the stator core 21 includes a plurality of electrical steel sheets 40 laminated in the axial direction.

Further, the stacking thickness of the stator core 21 is, for example, 50.0 mm. The outer diameter of the stator core 21, for example, is 250.0 mm. The inner diameter of the stator core 21, for example, is 165.0 mm. However, these values are examples, and the stacking thickness, outer diameter, and inner diameter of the stator core 21 are not limited to these values. Here, the inner diameter of the stator core 21 is measured with the tops of the teeth 23 of the stator core 21 as reference members. The inner diameter of the stator core 21 represents

- 3 042110 is the diameter of a virtual circle inscribed in the tops of all teeth 23.

Each electrical steel sheet 40 forming the stator core 21 and the rotor core 31 is formed, for example, by punching an electrical steel sheet serving as a base material. As the electrical steel sheet 40, a known electrical steel sheet may be used. The chemical composition of the electrical steel sheet 40 is not specifically limited. In the present embodiment, a grain-oriented electrical steel sheet is used as the electrical steel sheet 40 . As the non-grain-oriented electrical steel sheet, for example, a non-grain-oriented electrical steel strip according to JIS C 2552:2014 can be used.

However, as the electrical steel sheet 40, it is also possible to use a grain-oriented electrical steel sheet instead of a non-grain-oriented electrical steel sheet. As the grain-oriented electrical steel sheet, for example, a grain-oriented electrical steel strip according to JIS C 2553:2012 can be used.

Insulating coatings are provided on both surfaces of the electrical steel sheet 40 to improve the workability of the electrical steel sheet and the steel loss of the laminated core. As the insulating coating material, for example, (1) an inorganic compound, (2) an organic polymer, (3) a mixture of an inorganic compound and an organic polymer, and the like can be used. As the inorganic compound, for example, (1) a complex compound of dichromate and boric acid, (2) a complex compound of phosphate and silica, and the like can be illustrated. As the organic resin, epoxy resin, acrylic resin, acrylic styrene resin, polyester resin, silicone resin, and fluorine resin can be roughly illustrated.

In order to ensure the insulating performance between the electrical steel sheets 40 stacked on top of each other, the thickness of the insulating coating (thickness per surface of the electrical steel sheet 40) is preferably 0.1 µm or more.

On the other hand, the insulation effect saturates as the insulation coating becomes thicker. Further, as the insulating coating becomes thicker, the spatial ratio of the insulating coating in the stator core 21 increases, and the magnetic properties of the stator core 21 deteriorate. Therefore, the insulating coating can be as thin as possible while maintaining the performance of the insulation. The thickness of the insulating coating (thickness per side of the electrical steel sheet 40) is preferably 0.1 µm or more and 5 µm or less, and more preferably 0.1 µm or more and 2 µm or less.

As the electrical steel sheet 40 becomes thinner, the steel loss improvement effect gradually saturates. Further, as the electrical steel sheet 40 becomes thinner, the manufacturing cost of the electrical steel sheet 40 increases. For this reason, the thickness of the electrical steel sheet 40 is preferably 0.10 mm or more in view of the steel loss improvement effect and manufacturing cost.

On the other hand, if the electrical steel sheet 40 is too thick, the punching processing of the electrical steel sheet 40 becomes difficult. For this reason, in consideration of the punching processing of the electrical steel sheet 40, the thickness of the electrical steel sheet 40 is preferably 0.65 mm or less.

Additionally, as the electrical steel sheet 40 becomes thick, the steel loss increases. For this reason, considering the steel loss characteristics of the electrical steel sheet 40, the thickness of the electrical steel sheet 40 is preferably 0.35 mm or less, more preferably 0.20 mm or 0.25 mm.

Considering the above aspects, the thickness of each electrical steel sheet 40 is, for example, 0.10 mm or more and 0.65 mm or less, preferably 0.10 mm or more and 0.35 mm or less, and more preferably 0.20 mm or 0.25 mm. In addition, the thickness of the electrical steel sheet 40 also includes the thickness of the insulating coating.

A plurality of electrical steel sheets 40 forming the stator core 21 are adhered to each other by an adhesive portion 41. The adhesive portion 41 is an adhesive material that is provided between the electrical steel sheets 40 next to each other in the axial direction and is cured without separation. As the adhesive material, for example, a thermoset adhesive material by polymer bonding is used. As the adhesive composition, (1) acrylic resin, (2) epoxy resin, (3) composition containing acrylic resin and epoxy resin, and the like can be used. As such an adhesive material, a radical polymerization adhesive material and the like. can be used in addition to a thermosetting adhesive, and from a performance point of view, a room temperature curing adhesive is preferably used. Room temperature curing adhesive

- 4 042110 material cures at 20-30°C. As a room temperature curing adhesive, an acrylic adhesive is preferred. A typical acrylic adhesive includes a second generation acrylic adhesive (SGA) and the like. Any of the anaerobic adhesive, the instant adhesive, and the acrylic-based elastomeric adhesive can be used within a range where the benefits of the present invention are not impaired. In addition, the adhesive material mentioned herein is the adhesive material in the state before curing, and becomes the adhesive portion 41 after the adhesive material is cured.

The average tensile modulus E of the adhesive portion 41 at room temperature (2030° C.) is in the range of 1500-4500 MPa. If the average tensile modulus E of the adhesive portion 41 is less than 1500 MPa, a problem arises that the rigidity of the laminated core is lowered. For this reason, the lower limit of the average tensile modulus E of the adhesive portion 41 is 1500 MPa, more preferably 1800 MPa. Conversely, if the average tensile modulus E of the adhesive portion 41 exceeds 4500 MPa, there is a problem of peeling off the insulating coating formed on the surface of the electrical steel sheet 40 . For this reason, the upper limit of the average tensile modulus E of the adhesive portion 41 is 4500 MPa, more preferably 3650 MPa.

Additionally, the average tensile modulus E is measured by a resonance method. In particular, the tensile modulus is measured in accordance with JIS R 1602:1995.

More specifically, a measurement sample (not shown) is first made. This pattern is obtained by bonding between two electrical steel sheets 40 using an adhesive material that is the target of measurements, and curing them so as to form an adhesive portion 41. In a case in which the adhesive material is thermosetting, curing is performed by heating and making pressurization in it under conditions of heating and pressurization in the actual processing. On the other hand, in the case where the adhesive material is of the room temperature-curable type, curing is performed by pressurizing at room temperature.

In addition, the tensile modulus of this sample is measured using a resonance method. As described above, the method for measuring tensile modulus using the resonance method is performed in accordance with JIS R 1602:1995. Further, the tensile modulus of only the adhesive portion 41 is obtained by removing the influence of the electrical steel sheet 40 itself from the tensile modulus (measured value) of the sample by calculation.

Since the tensile modulus thus obtained from the sample is equal to the average value of the entire laminated core, this value is considered as the average tensile modulus E. The composition is set in such a way that the average tensile modulus E remains practically unchanged at the lamination position in the axial direction or at the circumferential position around the central axis of the laminated core. For this reason, the average tensile modulus E can be set to the value obtained by measuring the adhesive portion 41 after curing at the top end position of the laminated core.

The electric motor generates heat during operation. For this reason, when the melting point of the adhesive portion 41 is low, the adhesive portion 41 melts due to the heat generated by the motor, and the shape of the bonding region 42 changes so that a desired effect cannot be obtained. Typically, an insulating coating (enamel) is provided on the surface of the winding wound around the stator core 21. The heat resistant temperature of this coating, for example, is approximately 180°C. For this reason, the common motor is driven at 180° C. or lower. Thus, the motor can be heated up to approximately 180°C. In the present embodiment, the melting point of the adhesive portion 41 is preferably 180° C. or higher. Further, the melting point of the adhesive portion 41 is more preferably 200° C. or higher in view of the safety factor and in view of the fact that there is a portion in which the temperature is locally high.

As the bonding method, for example, a method in which an adhesive material is applied to electrical steel sheets 40 and then bonded by heat, pressure bonding, or both can be used. In addition, the heating means may be any means such as heating in a high temperature bath or electric furnace, or a direct power supply method.

In order to obtain stable and sufficient adhesive strength, the thickness of the adhesive portion 41 is preferably 1 µm or more.

On the other hand, if the thickness of the adhesive portion 41 exceeds 100 μm, the bonding force is saturated. Further, as the adhesive portion 41 becomes thicker, its spatial coefficient decreases and the magnetic properties such as loss in the laminated core steel deteriorate. Therefore, the thickness of the adhesive portion 41 is preferably 1 µm or more, and

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100 µm or less, and more preferably 1 µm or more and 10 µm or less.

Additionally, in the above description, the thickness of the adhesive portion 41 indicates the average thickness of the adhesive portion 41.

The average thickness of the adhesive portion 41 is more preferably 1.0 µm or more and 3.0 µm or less. If the average thickness of the adhesive portion 41 is less than 1.0 μm, sufficient adhesive strength cannot be ensured as described above. For this reason, the lower limit of the average thickness of the adhesive portion 41 is 1.0 µm, more preferably 1.2 µm. Conversely, if the average thickness of the adhesive portion 41 becomes larger than 3.0 μm, problems such as a significant increase in the tension amount of the electrical steel sheet 40 due to heat curing occur. For this reason, the upper limit of the average thickness of the adhesive portion 41 is 3.0 µm, more preferably 2.6 µm. The average thickness of the adhesive portion 41 is the average of the entire laminated core.

The average thickness of the adhesive portion 41 remains practically unchanged at the lamination position in the axial direction and at the circumferential position around the central axis of the laminated core. For this reason, the average thickness of the adhesive portion 41 may be set to the average of the numerical values measured at 10 or more points in the circumferential direction at the upper end position of the laminated core.

In addition, the average thickness of the adhesive portion 41 can be adjusted by changing, for example, the amount of applied adhesive. Additionally, for example, in the case of a thermoset adhesive, the average tensile modulus E of the adhesive portions 41 can be controlled by changing one or both of the heating and pressurization conditions applied during bonding and the type of curing agent.

Next, the relationships between the electrical steel sheets 40, the adhesive portions 41, and the bonding areas 42 will be described with reference to FIG. 4.

As shown in FIG. 4, the electrical steel sheets 40 adjacent to each other in the axial direction are not fully surface-bonded. These electrical steel sheets 40 are locally bonded to each other. Adhesive portions 41 are provided in a plurality of teeth 23 of electrical steel sheets. The teeth 23 are adhered to each other by the adhesive portions 41. Thus, a plurality of electrical steel sheets 40 are adhered to each other by the adhesive portions 41.

Bonded areas 42 and non-bonded areas (empty areas) are formed on the surfaces of the electrical steel sheets 40 facing the axial direction (hereinafter referred to as the first surfaces of the electrical steel sheet 40). Bond regions 42 are regions on first surfaces of electrical steel sheets 40 on which adhesive portions 41 are provided. More specifically, bond regions 42 are regions of first surfaces of electrical steel sheets 40 on which cured adhesive materials are provided. The non-adhesive areas are areas on the first surfaces of the electrical steel sheets on which the adhesive portions 41 are not provided.

One adhesive portion 41 is provided in one tooth 23. According to the present embodiment, the adhesive portions 41 are respectively provided on a plurality of teeth 23. For this reason, a plurality of adhesive portions 41 are provided discretely in the circumferential direction as all electrical steel sheets 40. As a result, the electrical steel sheets 40 can be attached to each other symmetrically.

The adhesive portion 41 forms a strip shape extending linearly in the circumferential direction. Therefore, the bonding area 42 also forms a strip shape extending linearly in the circumferential direction, similar to the adhesive portion 41. Thus, the bonding area 42 extends in a direction orthogonal to the direction in which the tooth 23 extends. The size across the width of the bonding area 42 is uniform in the entire length of the area 42 gluing. Additionally, the bonding region 42 is located near the tip of the tooth 23. Here, the vicinity of the tip of the tooth 23 is the range from the tip of the tooth 23 to 1/10 of the radial length of the tooth 23 along the radial length of the tooth 23.

In addition, in the present specification, the direction in which the tooth 23 extends (i.e., the radial direction) may be referred to as the length direction of the tooth 23, and the direction orthogonal to the length direction may be referred to as the width direction of the tooth 23.

Further, in the present specification, the shape of the strip as the shape in which the adhesive portion 41 extends indicates that the shape extends in one direction and its width is equal to or greater than 1.5% of the outer diameter of the stator core 21. By forming the width of the adhesive portion 41 so that it is equal to or greater than 1.5% of the outer diameter of the stator core 21, the adhesive strength between the electrical steel sheets 40 can be sufficiently secured.

In addition, in the present embodiment, a case is described in which the width dimension of the bonding region 42 is uniform along the entire length of the bonding region 42. However, the width dimension of the bonding region 42 need not be uniform. As an example, both

- 6 042110 the end portions of the gluing region 42 in the width direction can be wound and pulled in the length direction.

The adhesive portion 41 has a substantially rectangular shape, the longitudinal direction of which is orthogonal to the radial direction when viewed from above. According to the present embodiment, by forming the adhesive portion 41 so that it has a shape extending in one direction, the bonding area of the adhesive portion 41 can be increased to improve the bonding strength, compared with the case in which the adhesive portions 41 having a dot shape intermittently provided in the identical range.

By increasing the dimension d1 across the width of the adhesive portion 41, the adhesive portion 41 can be easily formed during the manufacturing process. Further, by reducing the dimension d1 across the width of the adhesive portion 41, deterioration in steel loss of the entire electrical steel sheet 40 can be prevented without causing a large local tension in the electrical steel sheet 40 due to the stress when compressing the adhesive material.

In addition, the width dimension d1 of the adhesive portion 41 is the size of the adhesive portion 41 forming a strip shape in the transverse direction, and is the dimension of the adhesive portion 41 in the radial direction in the present embodiment. In the present embodiment, since the bonding region 42 is the region in which the adhesive portion 41 is provided on the first surface of the electrical steel sheet 40, the width dimension of the bonding region 42 and the width dimension of the adhesive portion 41 are identical.

The adhesive portion 41 extends across the entire width of the tooth 23. According to the present embodiment, since the adhesive portion 41 forms a strip shape extending across the entire width of the tooth 23, the adhesive strength between the teeth 23 is easily secured.

In the present embodiment, the adhesive material shrinks upon curing. For this reason, curing shrinkage tension of the adhesive material occurs in the region of the electrical steel sheet 40 in contact with the bonding region 42, and the steel loss of the electrical steel sheet 40 increases in the region. Here, in the first surface of the electrical steel sheet 40, the region in which the steel loss increases due to the tension resulting from contact with the adhesive portion 41 is called the degradation region 29 . The degraded area 29 is an area that overlaps the bonding area 42 when viewed from the axial direction. The degraded region 29 has a higher magnetic resistance than other regions (non-degraded regions).

In the present detailed description, an increase in the iron loss value may be referred to as a deterioration in iron loss.

The magnetic flux B is generated on the electrical steel sheet 40 by the current flowing through the winding (not shown) of the stator 20. The magnetic flux B forms a magnetic circuit that passes through the tooth 23 and the back portion 22 of the core. The magnetic flux B passes in the radial direction in the tooth 23.

According to the present embodiment, the bonding area 42 is formed in the tooth 23 with the shape of a strip extending in the circumferential direction. Therefore, the degraded region 29 is formed in the tooth 23 with a band shape extending in the circumferential direction. As described above, the magnetic flux B flows in the tooth 23 in the radial direction. For this reason, by forming the bonding area 42 having the shape of a strip extending in the circumferential direction in the tooth 23, the length of the magnetic flux path B passing through the degrading area 29 is shortened. As a result, the magnetic resistance to the magnetic flux B in the magnetic circuit is lowered, so that the magnetic properties of the stator core 21 can be improved as compared with the case in which electrical steel sheets are attached to each other by fastening.

In the present embodiment, the rotor core 31 is a laminated core, similar to the stator core 21. Thus, the rotor core 31 includes a plurality of electrical steel sheets laminated in its thickness direction. In the present embodiment, the stacking thickness of the rotor core 31 is equal to the stacking thickness of the stator core 21, for example, 50.0 mm. The outer diameter of the rotor core 31, for example, is 163.0 mm. The inner diameter of the rotor core 31, for example, is 30.0 mm. However, these values are examples, and the stacking thickness, outer diameter, and inner diameter of the rotor core 31 are not limited to these values.

In the present embodiment, a plurality of electrical steel sheets forming the rotor core 31 are attached to each other by fastening C (dowels, see FIG. 1). However, a plurality of electrical steel sheets 40 forming the rotor core 31 can be adhered to each other by adhesive portions.

In addition, laminated cores such as the stator core 21 and the rotor core 31 can be formed by so-called coil stacking.

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modified example 1.

Next, the adhesive portion 141 and the adhesive portion 142 of the modified Example 1 that can be used in the above-described embodiment will be described with reference to FIG. 5. In addition, components with identical aspects to those in the above-described embodiment are denoted by identical numerals, and their descriptions are omitted.

Similar to the above-described embodiment, the barb 23 has a bonding region 142 comprising an adhesive portion 141 shaped as a strip extending in the circumferential direction. The adhesive portion 141 of the present modified example mainly differs from the adhesive portion 141 of the above embodiment in that the adhesive portion 142 is located near the base end of the prong 23.

Similar to the above embodiment, the bonding region 142 forms a strip shape extending linearly along the circumferential direction. The width dimension of the bonding region 142 is uniform along the entire length of the bonding region 142. A region (deterioration region 129) in which steel loss increases due to tension resulting from contact with the bonding region 142 is formed in the electrical steel sheet 40 . According to the present modified example, since the length of the magnetic flux path B passing through the degrading region 129 is shortened, the magnetic resistance to the magnetic flux B in the magnetic circuit is reduced, so that the magnetic properties of the stator core 21 can be improved.

The magnetic flux B dissipates and passes from the top of the tooth 23 in both circumferential directions. For this reason, near the tip of the tooth 23, the magnetic flux B is concentrated in both circumferential end portions, and the magnetic flux density tends to increase. If a degradation region is provided in a region having a high magnetic flux density, the increase in iron loss tends to be significant. For this reason, if a degradation region 129 is provided near the top of the tooth 23, the iron loss tends to increase. The bonding region 142 of the present modified example is formed near the base end of the tooth 23. Thus, the bonding region 142 is formed on the side closer to the core back portion 22 than to the vicinity of the tip of the tooth 23. For this reason, the degradation region 129 may be located at a large distance from the region having a high magnetic flux density, so that an increase in steel loss can be prevented. As a result, the magnetic resistance to the magnetic flux B in the magnetic circuit is reduced, so that the magnetic properties of the stator core 21 can be improved. If the bonding region 142 is located on the basic end side with respect to 1/2 of the entire length of the tooth 23, the above effect can be obtained, and if the bonding region 142 is located on the basic end side with respect to 1/3 of the entire length of the tooth 23, the above effect can be obtained to a greater extent .

modified example 2.

Next, the adhesive portion 241 and the bonding area 242 of the modified example 2 that can be used in the above-described embodiment will be described with reference to FIG. 6. In addition, components with aspects identical to those in the above-described embodiment are designated by identical reference numbers, and their descriptions are omitted.

Similar to the above embodiment, the barb 23 has a bonding region 242 comprising an adhesive portion 241 shaped like a strip extending in the circumferential direction. The adhesive portion 241 of the present modified example mainly differs from the adhesive portion 241 of the above embodiment in that the bonding region 242 is formed substantially at the center of the tooth 23 in the length direction.

Similar to the above embodiment, since the bonding area 242 forms a strip shape extending linearly in the circumferential direction, the length of the magnetic flux path B passing through the degrading area 229 can be shortened. As a result, the magnetic resistance to the magnetic flux B in the magnetic circuit is reduced, so that the magnetic properties of the stator core 21 can be improved. Moreover, the bonding region 242 of the present modified example is uniform along the entire length of the bonding region 242.

Further, since the bonding area 242 of this modified example is located on the side closer to the core back portion 22 than to the vicinity of the tip of the tooth 23, similarly to the bonding area 242 of the modified example 1, an increase in iron loss can be prevented. As a result, the magnetic resistance to the magnetic flux B in the magnetic circuit is reduced, so that the magnetic properties of the stator core 21 can be improved.

Modified example 3.

Next, the adhesive portion 341 and the adhesive portion 342 of the modified Example 3 that can be used in the above-described embodiment will be described with reference to FIG. 7. In addition, components with aspects identical to those in the above-described embodiment are designated by identical reference numbers, and their descriptions are omitted.

Similar to the above embodiment, the barb 23 has a bonding region 342 comprising an adhesive portion 341 shaped as a strip extending in the circumferential direction. Region

- 8 042110

The bonding area 342 of the present Modified Example is similar to the configuration of the bonding area 242 of the Modified Example 2. According to the stator core 21 having the adhesive portion 341 of the present Modified Example, effects identical to those of the stator core 21 having the adhesive portion 241 of the Modified Example 2 can be obtained. of the modified example differs from the bonding area 242 of the modified example 2 in that the width dimension is not uniform along the entire length of the bonding area 342.

Both end portions of the bonding area 342 in the width direction of the present modified example are curved. Both end portions of the bonding region 342 in the width direction are separated from each other from the circumferential center portion of the tooth 23 to the sides of the circumferential end portions of the tooth 23. For this reason, the width dimension of the bonding region 342 in the radial direction increases from the circumferential center portion in the direction of the tooth 23 to the sides. the circumferential end portions of the prong 23. The bonding region 342 is smallest in width at the circumferential center portion of the prong 23.

As shown in FIG. 4, the magnetic flux B dissipates and passes from the top of the tooth 23 to both circumferential directions. Additionally, magnetic flux B tends to flow in such a way that it travels the shortest distance. For this reason, the magnetic flux density of the tooth 23 tends to increase towards the sides of the circumferential end portions. If the variation in the magnetic flux density of the tooth 23 increases in the circumferential direction, the magnetic properties of the stator core 21 may deteriorate.

According to the present modified example, the width dimension of the bonding region 342 in the radial direction increases from the central portion of the tooth 23 to the sides of the circumferential end portions. Thus, the length of the deterioration area 391 in the radial direction increases from the central portion of the tooth 23 to the sides of the end portions in the width direction. For this reason, the magnetic resistance of the tooth 23 increases towards the sides of the circumferential end portions, and it is unlikely that the magnetic flux B should flow on the sides of the circumferential end portions. Thus, variation of the magnetic flux density in the circumferential direction of the tooth 23 can be prevented, and the magnetic flux density in the tooth 23 can become uniform. As a result, the magnetic properties of the laminated core can be improved.

Modified example 4.

Next, the adhesive portion 441 and the adhesive portion 442 of the modified Example 4 that can be used in the above-described embodiment will be described with reference to FIG. 8. In addition, components with identical aspects to those in the above-described embodiment are designated by identical reference numbers, and their descriptions are omitted.

Similar to the above embodiment, a bonding area 442 comprising an adhesive portion 441 having a strip shape extending linearly in the circumferential direction is provided in a tooth 23. Further, the adhesive portion 441 of the present modified example mainly differs from the above embodiment in that a plurality of (three ) bonding regions 442 placed in the pull direction are formed in the tooth 23. A plurality of bonding regions 442 are placed in the immediate vicinity of the center in the length direction of the tooth 23 towards the base end side.

As shown in the present modified example, a plurality of bonding areas 441 may be provided for each tooth 23 in the above embodiment and in each modified example. Even in this case, the effects of the embodiments and modified examples can be obtained, and in addition, the adhesive strength between the electrical steel sheets 40 can be increased.

In the case where a plurality of bonding areas 442 are provided in one tooth 23, the width dimension of the bonding area 442 is preferably smaller than the spacing between adjacent bonding areas 442. As a result, it is possible to prevent tension on the electrical steel sheet due to the plurality of bonding regions 442, thereby preventing deterioration (increase) in steel loss of the electrical steel sheet.

Modified example 5.

Next, the adhesive portion 541 and the bonding region 542 of the modified Example 5 that can be used in the above-described embodiment will be described with reference to FIG. 9. In addition, components with aspects identical to those in the above-described embodiment are designated by identical reference numbers, and their descriptions are omitted.

Similar to the above embodiment, a bonding region 542 comprising an adhesive portion 541 shaped like a band extending in the circumferential direction is provided in a tooth 23. The adhesive portion 541 of the present modified example differs mainly from the above embodiment in that the bonding region 542 extends in an arcuate form in the circumferential direction. Since the adhesive portion 541 of the present modified example can be uniformly applied in the circumferential direction, the manufacturing process can be simplified.

- 9 042110

In addition, the scope of the present invention is not limited to the above embodiment and modified examples, and various changes can be made thereto without departing from the gist of the present invention.

In the stator core of the above embodiment and its modified examples, a plurality of electrical steel sheets are attached to each other in an adhesive portion provided in a tooth. However, the electrical steel sheets can be attached to each other not only in the tooth but also in the back portion of the core. In this case, the back portion of the core may comprise a fastening portion, or the back portion of the core may comprise a separate adhesive portion. Additionally, the electrical steel sheets can be welded and attached to each other in addition to being fixed by gluing due to the adhesive portion. Thus, the effects of the present embodiment can be obtained regardless of the method of fixing the back portion of the core.

The shape of the stator core is not limited to the shape shown in the above embodiment. In particular, the dimensions of the outer diameter and the inner diameter of the stator core 21, the stacking thickness, the number of slots, the size ratio of the tooth 23 between the circumferential direction and the radial direction, the size ratio in the radial direction between the tooth 23 and the core back portion 22, and the like. can be freely calculated according to the required properties of the motor.

In the rotor of the above embodiment, a set of two permanent magnets 32 forms one magnetic pole, but the present invention is not limited to this. For example, one permanent magnet 32 may form one magnetic pole, or three or more permanent magnets 32 may form one magnetic pole.

In the above-described embodiment, the permanent magnet motor is described as an example of the motor, but as illustrated below, the structure of the motor is not limited to this, and various well-known structures not illustrated below can also be used.

In the above-described embodiment, the permanent magnet motor is described as an example of a synchronous motor, but the present invention is not limited thereto. For example, the motor may be a reluctance motor or an electromagnetic field motor (two winding motor).

In the above embodiment, the synchronous motor is described as an example of an AC motor, but the present invention is not limited thereto. For example, the motor may be an induction motor.

In the above embodiment, the AC motor is described as an example of the motor, but the present invention is not limited thereto. For example, the motor may be a DC motor.

In embodiments, a motor is described as an example of a motor, but the present invention is not limited thereto. For example, the electric motor may be a generator.

In the above embodiment, a case is shown in which the laminated core according to the present invention is applied to a stator core, but it can also be applied to a rotor core.

In addition, the components in the embodiment and its modified examples can be replaced with known components in an appropriate manner, and the above modified examples can be combined with each other in an appropriate manner without departing from the gist of the present invention.

Example.

A proof test was carried out in order to check the prevention of deterioration in steel loss of electrical steel sheets due to mechanical stress when compressing the adhesive portion. This proof test is performed by simulation using software. The software used was JMAG, a finite element electromagnetic field simulation software developed by JSOL Corporation. As the model used for the simulation, the stator cores (laminated cores) of models 1-4 described below are assumed. As the electrical steel sheets used for each model, electrical steel sheets made by punching thin sheets having a sheet thickness of 0.25 mm and a sheet thickness of 0.20 mm are used. The shape of the electrical steel sheet is identical to that shown in FIG. 2.

The fixing structure of the electrical steel sheets differs between the stator cores of models No. 1-3 and the stator core of models No. 4. In the stator cores of models Nos. 1-3, an adhesive part is provided between the electrical steel sheets, and the electrical steel sheets are attached by gluing to each other. On the other hand, in the stator core of model number 4, electrical steel sheets are attached to each other by means of fastening.

- 10 042110

The bonding area of model number 1 corresponds to the bonding area 42 shown in FIG. 4.

Pattern number 1 bonding areas are formed in a plurality of teeth, and each bonding area forms a band shape extending linearly in the circumferential direction near the top of the tooth.

The bonding region of model number 2 corresponds to the bonding region 142 shown in FIG. 5. Pattern number 2 bonding areas are formed in a plurality of teeth, and each bonding area forms a band shape extending linearly in the circumferential direction near the base end of the tooth.

The bonding area of model number 3 corresponds to the bonding area 242 shown in FIG. 6. Pattern number 3 bonding areas are formed in a plurality of teeth, and each bonding area forms a strip shape extending linearly in the circumferential direction at the center of the tooth in the length direction.

A model number 4 stator core 1021 is shown in FIG. 11. The stator core 1021 is formed by laminating electrical steel sheets 40 having the same shape as the stator core 21 of the above-described embodiment in the thickness direction. The stator core 1021 differs from the stator core 21 of the above embodiment in that the electrical steel sheets 40 are fastened and attached to each other. Thus, the electrical steel sheets 40 of the stator core 1021 are attached to each other by means of the attachment 1042 (dowels). Attachment 1042 is located in tooth 23.

For each model in Fig. 10 shows the calculation results of the steel loss of the electrical steel sheet calculated by the simulation software. Additionally, in steel loss (vertical axis) from the calculation results shown in FIG. 10, the loss in steel model number 4 is set to 1.0, and the loss in steel of another model is expressed as their ratio with respect to the loss in steel model number 4.

As shown in FIG. 10, it is confirmed that the stator cores of model numbers 1 to 3 have lower steel loss values than the steel loss values of model number 4 stator core.

The model number 1 stator core has higher steel losses than the model number 2 and model number 3 stator cores. In the model number 1 stator core, as shown in FIG. 4, it is considered that since the bonding area is located near the tip of the tooth, the iron loss is increased because the degrading area is provided in the area having a high magnetic flux density. On the other hand, in the stator cores of model number 2 and model number 3, as shown in FIG. 5 and 6, it is considered that the degraded area can be located at a large distance from the area having a high magnetic flux density, and an increase in steel loss is prevented.

Industrial Applicability

According to the present invention, the magnetic properties can be improved. Hence, it provides wide industrial applicability.

Brief description of links with numbers

- electric motor;

- stator;

- stator core (laminated core);

- part of the back of the core;

- tooth;

- a sheet of electrical steel;

, 141, 241, 341 - adhesive part;

, 142, 242, 342 - gluing area;

d1 - size in width;

B is the magnetic flux.

Claims (10)

CLAIM 1. A laminated core comprising a plurality of electrical steel sheets stacked on top of each other, wherein each of the electrical steel sheets is formed with an annular back portion of the core and a plurality of teeth that extend from the annular portion of the back of the core in the radial direction and are spaced at intervals in the circumferential direction. parts of the back of the core; and bonding areas provided on the surface of each of the teeth, between axially adjacent electrical steel sheets, so as to bond the electrical steel sheets to each other, each bonding area having an adhesive portion shaped as a strip extending in the circumferential direction with a width equal to or exceeding 1.5% of the outer diameter of the annular portion of the back of the core. 2. A laminated core according to claim 1, wherein the bonded areas are formed on the teeth closer to the annular portion of the back of the core than to the tops of the teeth. - 11 042110 3. The laminated core according to claim 1 or 2, wherein the width dimensions of the bonding areas in the radial direction increase from the circumferential tooth centers towards the sides of the circumferential end portions of the teeth. 4. A laminated core according to claim 1 or 2, wherein the areas of bonding are arcuate in the circumferential direction. 5. A laminated core according to any one of claims 1 to 4, wherein the adhesive portions extend over all tooth widths. 6. Laminated core according to any one of claims 1 to 5, wherein the average thickness of the adhesive portions is 1.0-3.0 µm. 7. The laminated core according to any one of claims 1 to 6, wherein the average tensile modulus E of the adhesive portions is 1500-4500 MPa. 8. The laminated core according to any one of claims 1 to 7, wherein the adhesive portions are room temperature adhesive acrylic-based adhesives containing a second generation acrylic adhesive made from an elastomer-containing acrylic-based adhesive. 9. The laminated core according to any one of claims 1 to 8, wherein the melting point of each of the adhesive portions is 180° C. or higher. 10. An electric motor containing a laminated core according to any one of claims 1 to 9.