Patent Description:
Conventionally, a laminated core in which a plurality of electrical steel sheets are laminated on each other is known as a core used in an electric motor. The plurality of electrical steel sheets are joined by a method such as welding, adhesion, fastening, or the like. However, joining by welding or fastening makes it difficult to reduce vibration of an electric motor and obtain a high mechanical strength.

<CIT> discloses a laminated core in which electrical steel sheets are partially adhered and laminated with a cyanoacrylate-based adhesive, and then the electrical steel sheets are entirely adhered to each other by being vacuum-impregnated with an epoxy resin. <CIT> discloses a laminated core in which a laminate in which electrical steel sheets are laminated is coated with a cyanoacrylate-based instant adhesive on a side surface thereof to be temporarily fixed, and then the electrical steel sheets are entirely adhered to each other by being impregnated with a thermosetting resin such as an epoxy resin. <CIT> describes a method of manufacturing a motor comprising a process of applying a room temperature curing type adhesive to a first area of a strip of electromagnetic steel sheet, and a process of applying a thermosetting adhesive to a second area of said strip of electromagnetic steel sheet. <CIT> relates to two non-oriented electrical steel sheets of <NUM>-<NUM> thick are laminated via an adhesive layer, where the adhesive layer is provided with dot-like adhesive parts, in zigzag, on the adhesive surface of the non-oriented electrical steel sheet. <CIT> describes a method of producing a laminated steel plate by laminating a plurality of steel plates. <CIT> relates to a motor including a bearing housing and a stator. <CIT> relates to an insulating material used on an electrical machine for insulating turns of wound coil assemblies.

However, the conventional methods such as <CIT> and <CIT> have poor productivity, and iron loss that can be incurred in the electric motor cannot be sufficiently suppressed.

An object of the present invention is to provide an adhesively-laminated core for a stator having excellent productivity and high mechanical strength and that is thus capable of reducing vibration and noise of an electric motor and suppressing iron loss, a method of manufacturing the same, and an electric motor including the adhesively-laminated core for a stator.

insulation coating, and an adhesion part which is disposed between the electrical steel sheets adjacent to each other in a stacking direction and adheres the electrical steel sheets to each other, in which all sets of the electrical steel sheets adjacent to each other in the stacking direction are adhered by a plurality of adhesion parts, an adhesive forming the adhesion part includes a fast-curing type adhesive and a thermosetting adhesive, and the adhesion part is partially provided between the electrical steel sheets adjacent to each other in the stacking direction.

[<NUM>] The adhesively-laminated core for a stator according to [<NUM>], in which the adhesion part includes a first adhesion part formed with the fast-curing type adhesive, and a second adhesion part formed with the thermosetting adhesive.

[<NUM>] The adhesively-laminated core for a stator according to [<NUM>], in which the adhesion part includes the first adhesion part provided between tooth parts of the electrical steel sheets, and the second adhesion part provided between core back parts of the electrical steel sheets.

[<NUM>] The adhesively-laminated core for a stator according to [<NUM>] or [<NUM>], in which the first adhesion part has a dot shape with an average diameter of <NUM> or more and <NUM> or less, the second adhesion part has a dot shape with an average diameter of <NUM> or more and <NUM> or less, and a proportion of an adhesion area of the first adhesion part is <NUM>% or more and <NUM>% or less and a proportion of an adhesion area of the second adhesion part is <NUM>% or more and <NUM>% or less with respect to a total adhesion area of the adhesion part between the electrical steel sheets.

[<NUM>] The adhesively-laminated core for a stator according to [<NUM>] or [<NUM>], in which the first adhesion part has a dot shape with an average diameter of <NUM> or more and <NUM> or less, the second adhesion part has a dot shape with an average diameter of <NUM> or more and <NUM> or less, and a proportion of an adhesion area of the first adhesion part.

According to the present invention, it is possible to provide an adhesively-laminated core for a stator having excellent productivity and high mechanical strength and that is thus capable of reducing vibration and noise of an electric motor and suppressing iron loss, a method of manufacturing the same, and an electric motor including the adhesively-laminated core for a stator.

Hereinafter, an adhesively-laminated core for a stator according to one embodiment of the present invention and an electric motor including the adhesively-laminated core for a stator will be described with reference to the drawings. In the present embodiment, a motor, specifically an AC motor, more specifically a synchronous motor, and even more specifically a permanent magnetic electric motor, will be described as one example of the electric motor. A motor of this type is suitably employed for, for example, an electric automobile.

As illustrated in <FIG>, an electric motor <NUM> includes a stator <NUM>, a rotor <NUM>, a case <NUM>, and a rotary shaft <NUM>. The stator <NUM> and the rotor <NUM> are accommodated in the case <NUM>. The stator <NUM> is fixed to an inside of the case <NUM>.

In the present embodiment, an inner rotor type in which the rotor <NUM> is positioned on a radially inner side of the stator <NUM> is employed as the electric motor <NUM>. However, an outer rotor type in which the rotor <NUM> is positioned on an outer side of the stator <NUM> may also be employed as the electric motor <NUM>. Also, in the present embodiment, the electric motor <NUM> is a <NUM>-pole <NUM>-slot three-phase AC motor. However, the number of poles, the number of slots, the number of phases, or the like can be changed as appropriate.

The electric motor <NUM> can rotate at a rotation speed of <NUM> rpm by applying, for example, an excitation current having an effective value of <NUM> A and a frequency of <NUM> to each phase.

The stator <NUM> includes an adhesively-laminated core for a stator (hereinafter referred to as a stator core) <NUM> and a winding (not illustrated).

The stator core <NUM> includes an annular core back part <NUM> and a plurality of tooth parts <NUM>. Hereinafter, a direction along a central axis O of the stator core <NUM> (or the core back part <NUM>) is referred to as an axial direction, a radial direction of the stator core <NUM> (or the core back part <NUM>) (i.e., a direction orthogonal to the central axis O) is referred to as a radial direction, and a circumferential direction of the stator core <NUM> (or the core back part <NUM>) (i.e., a direction revolving around the central axis O) is referred to as a circumferential direction.

The core back part <NUM> is formed in an annular shape in a plan view of the stator <NUM> along the axial direction.

The plurality of tooth parts <NUM> protrude inward in the radial direction (toward the central axis O of the core back part <NUM> in the radial direction) from an inner circumference of the core back part <NUM>. The plurality of tooth parts <NUM> are disposed at equiangular intervals in the circumferential direction. In the present embodiment, <NUM> tooth parts <NUM> are provided at every <NUM> degrees in terms of the central angle with the central axis O as a center. The plurality of tooth parts <NUM> are formed to have the same shape and the same size with each other. Therefore, the plurality of tooth parts <NUM> have the same thickness dimension with each other.

The windings are wound around the tooth parts <NUM>. The windings may be a concentrated windings or a distributed windings.

The rotor <NUM> is disposed on a radially inner side with respect to the stator <NUM> (the stator core <NUM>). The rotor <NUM> includes a rotor core <NUM> and a plurality of permanent magnets <NUM>.

The rotor core <NUM> is formed in a ring shape (an annular shape) disposed coaxially with the stator <NUM>. The rotary shaft <NUM> is disposed in the rotor core <NUM>. The rotary shaft <NUM> is fixed to the rotor core <NUM>.

The plurality of permanent magnets <NUM> are fixed to the rotor core <NUM>. In the present embodiment, a set of two permanent magnets <NUM> forms one magnetic pole. The plurality of sets of permanent magnets <NUM> are disposed at equiangular intervals in the circumferential direction. In the present embodiment, <NUM> sets of the permanent magnets <NUM> (<NUM> in total) are provided at every <NUM> degrees in terms of the central angle with the central axis O as a center.

In the present embodiment, an interior permanent magnet motor is adopted as the permanent magnetic electric motor. A plurality of through holes <NUM> penetrating the rotor core <NUM> in the axial direction are formed in the rotor core <NUM>. The plurality of through holes <NUM> are provided to correspond to a disposition of the plurality of permanent magnets <NUM>. The permanent magnets <NUM> are each fixed to the rotor core <NUM> in a state in which it is disposed inside the corresponding through hole <NUM>. Fixing of each permanent magnet <NUM> to the rotor core <NUM> can be realized, for example, by causing an outer surface of the permanent magnet <NUM> and an inner surface of the through hole <NUM> to be adhered to each other using an adhesive or the like. Further, a surface permanent magnet motor may be adopted as the permanent magnetic electric motor instead of an interior permanent magnet motor.

The stator core <NUM> and the rotor core <NUM> are both laminated cores. As illustrated in <FIG>, the stator core <NUM> may be formed by, for example, laminating a plurality of electrical steel sheets <NUM>.

Further, laminated thicknesses (the entire length along the central axis O) of the stator core <NUM> and the rotor core <NUM> may each be, for example, <NUM>. An outer diameter of the stator core <NUM> may be, for example, <NUM>. An inner diameter of the stator core <NUM> may be, for example, <NUM>. An outer diameter of the rotor core <NUM> may be, for example, <NUM>. An inner diameter of the rotor core <NUM> may be, for example, <NUM>. However, these values are an example, and the laminated thickness, the outer diameter, and the inner diameter of the stator core <NUM>, and the laminated thickness, the outer diameter, and the inner diameter of the rotor core <NUM> are not limited only to these values. Here, an edge portion of the tooth part <NUM> of the stator core <NUM> is used as a reference of the inner diameter of the stator core <NUM>. That is, the inner diameter of the stator core <NUM> is a diameter of a virtual circle inscribed in the edge portions of all the tooth parts <NUM>.

Each of the electrical steel sheets <NUM> forming the stator core <NUM> and the rotor core <NUM> may be formed by, for example, punching an electrical steel sheet serving as a base material or the like. As the electrical steel sheet <NUM>, a known electrical steel sheet can be used. A chemical composition of the electrical steel sheet <NUM> is not particularly limited. In the present embodiment, a non-grain-oriented electrical steel sheet is used as the electrical steel sheet <NUM>. As the non-grain-oriented electrical steel sheet, for example, a non-grain-oriented electrical steel strip of JIS C <NUM>:<NUM> can be adopted.

However, as the electrical steel sheet <NUM>, 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 of JIS C <NUM>:<NUM> can be adopted.

In order to improve workability of the electrical steel sheets and iron loss of the stator core, both sides of the electrical steel sheets <NUM> are preferably coated with an insulation coating. As a material constituting the insulation coating, for example, (<NUM>) an inorganic compound, (<NUM>) an organic resin, (<NUM>) a mixture of an inorganic compound and an organic resin, or the like can be adopted. As the inorganic compound, for example, (<NUM>) a compound of dichromate and boric acid, and (<NUM>) a compound of phosphate and silica or the like can be exemplified. As the organic resin, an epoxy resin, an acrylic resin, an acrylic-styrene resin, a polyester resin, a silicone resin, a fluorine resin, or the like can be exemplified.

When the electrical steel sheets <NUM> are coated with the insulation coating, a thickness of the insulation coating (average thickness per one surface of the electrical steel sheet <NUM>) is preferably <NUM> or more to secure insulation performance between the electrical steel sheets <NUM> laminated on each other.

On the other hand, an insulating effect becomes saturated as the insulation coating becomes thicker. Also, as the insulation coating becomes thicker, a space factor decreases and performance of the stator core deteriorates. Therefore, the insulation coating is preferably made thin in a range in which the insulating performance can be secured. The thickness of the insulation coating (thickness per one surface of the electrical steel sheet <NUM>) is preferably <NUM> or more and <NUM> or less, and more preferably <NUM> or more and <NUM> or less.

As a sheet thickness of the electrical steel sheet <NUM> becomes thinner, an effect of improving iron loss gradually saturates. Also, as the electrical steel sheet <NUM> becomes thinner, a manufacturing cost of the electrical steel sheet <NUM> increases. Therefore, the thickness of the electrical steel sheet <NUM> is preferably <NUM> or more when the effect of improving iron loss and the manufacturing costs are considered.

On the other hand, if the electrical steel sheet <NUM> is too thick, the iron loss increases. Therefore, when iron loss characteristics of the electrical steel sheet <NUM> are considered, the thickness of the electrical steel sheet <NUM> is preferably <NUM> or less, and more preferably <NUM> or <NUM>.

In consideration of the above-described points, the thickness of each electrical steel sheet <NUM> may be, for example, <NUM> or more and <NUM> or less, preferably <NUM> or more and <NUM> or less, and more preferably <NUM> or <NUM>. Further, the thickness of the electrical steel sheet <NUM> includes the thickness of the insulation coating.

As illustrated in <FIG>, in the stator core <NUM>, an adhesion part <NUM> that causes the electrical steel sheets <NUM> to be adhered to each other is partially provided between all sets of the electrical steel sheets <NUM> adjacent to each other in a stacking direction. All the sets of the electrical steel sheets <NUM> adjacent to each other in the stacking direction are laminated via the adhesion part <NUM> that is partially provided therebetween. The electrical steel sheets <NUM> adjacent to each other in the stacking direction are not fixed by other means (for example, fastening or the like).

The adhesion part <NUM> is one for causing the electrical steel sheets <NUM> adjacent to each other in the stacking direction to be adhered. The adhesion part <NUM> is an adhesive that is cured without being divided.

As illustrated in <FIG>, the adhesion part <NUM> includes a first adhesion part 41a and a second adhesion part 41b. The first adhesion part 41a is a fast-curing type adhesive that is cured without being divided. The second adhesion part 41b is a thermosetting adhesive that is cured without being divided. The first adhesion part 41a and the second adhesion part 41b are formed in a dot shape between the electrical steel sheets <NUM> adjacent to each other in the stacking direction.

A thickness of the adhesion part <NUM> is preferably <NUM> or more to obtain a stable and sufficient adhesion strength.

On the other hand, when the thickness of the adhesion part <NUM> exceeds <NUM>, an adhesion force is saturated. Also, as the adhesion part <NUM> becomes thicker, a space factor decreases, and magnetic properties such as iron loss of the stator core deteriorate. Therefore, the thickness of the adhesion part <NUM> is preferably <NUM> or more and <NUM> or less, and more preferably <NUM> or more and <NUM> or less.

Further, in the above description, the thickness of the adhesion part <NUM> means an average thickness of the adhesion parts <NUM>.

The average thickness of the adhesion parts <NUM> is more preferably <NUM> or more and <NUM> or less. When the average thickness of the adhesion parts <NUM> is less than <NUM>, a sufficient adhesion force cannot be secured as described above. Therefore, a lower limit value of the average thickness of the adhesion parts <NUM> is <NUM>, and more preferably <NUM>. Conversely, when the average thickness of the adhesion parts <NUM> increases more than <NUM>, a problem such as a large increase in strain amount of the electrical steel sheet <NUM> due to thermosetting shrinkage occurs. Therefore, an upper limit value of the average thickness of the adhesion parts <NUM> is <NUM>, and more preferably <NUM>.

The average thickness of the adhesion parts <NUM> is an average value as the entire laminated core. The average thickness of the adhesion parts <NUM> hardly changes throughout laminated positions in the stacking direction and circumferential positions around the central axis of the laminated core. Therefore, the average thickness of the adhesion parts <NUM> can be set to an average value of numerical values measured at <NUM> or more points in the circumferential direction at upper end positions of the laminated core.

The adhesion part <NUM> is partially provided between the electrical steel sheets <NUM> adjacent to each other in the stacking direction. That is, an adhesion region <NUM> and a non-adhesion region <NUM> are formed on a surface (first surface) of the electrical steel sheet <NUM> facing in the stacking direction. The adhesion region <NUM> is a region of the first surface of the electrical steel sheet <NUM> at which the adhesion part <NUM> is provided, that is, a region of the first surface of the electrical steel sheet <NUM> at which the adhesive cured without being divided is provided. The non-adhesion region <NUM> is a region of the first surface of the electrical steel sheet <NUM> at which the adhesion part <NUM> is not provided, that is, a region of the first surface of the electrical steel sheet <NUM> at which the adhesive cured without being divided is not provided. Between the electrical steel sheets <NUM> adjacent to each other in the stacking direction in the stator core <NUM>, it is preferable that the adhesion part <NUM> be partially provided between the core back parts <NUM> and be partially provided between the tooth parts <NUM> as well.

Typically, the adhesion part <NUM> is disposed to be distributed to a plurality of positions between the electrical steel sheets <NUM> adjacent to each other in the stacking direction.

<FIG> is an example of a disposition pattern of the adhesion part <NUM>. In this example, the first adhesion part 41a and the second adhesion part 41b are formed in a plurality of circular dots. More specifically, in the core back part <NUM>, a plurality of second adhesion parts 41b are formed in a dot shape with an average diameter of <NUM> at equiangular intervals in the circumferential direction. Some of each second adhesion part 41b protrudes to the tooth part <NUM>. In the tooth part <NUM>, a plurality of first adhesion parts 41a are formed in a dot shape with an average diameter of <NUM> in the radial direction.

The average diameter illustrated here is an example. The average diameter of the dot-shaped second adhesion part 41b is preferably <NUM> or more and <NUM> or less, and more preferably <NUM> or more and <NUM> or less. The average diameter of the dot-shaped first adhesion part 41a is preferably <NUM> or more and <NUM> or less, and more preferably <NUM> or more and less than <NUM>. The average diameter of the first adhesion part 41a is preferably smaller than the average diameter of the second adhesion part 41b.

Further, the formation pattern of <FIG> is an example, and the number, shape, and disposition of the adhesion parts <NUM> provided between the electrical steel sheets <NUM> can be appropriately changed as necessary.

The average diameter can be obtained by measuring diameters of adhesive marks of the adhesion parts <NUM> when the electrical steel sheets <NUM> are broken away from each other with a ruler. When a shape of the adhesive mark in a plan view is not a perfect circle, a diameter thereof is set as a diameter of a circumscribed circle (perfect circle) of the adhesive mark in a plan view.

Average diameters of the first adhesion part and the second adhesion part in the tooth parts and the core back part may not be the same.

Generally, curing shrinkage occurs when an adhesive is cured. Due to the curing shrinkage, compressive stress and tensile stress are applied to the electrical steel sheets <NUM>. When these stresses are applied to the electrical steel sheets <NUM>, a strain is caused. Particularly, in a case of a thermosetting adhesive, the applied stress increases due to a difference in thermal expansion coefficient between the electrical steel sheet <NUM> and the adhesion part. The strain of the electrical steel sheet <NUM> increases iron loss of the electric motor <NUM>. An influence of the strain of the electrical steel sheet <NUM> constituting the stator core <NUM> on the iron loss is larger than an influence of the strain of the steel sheet constituting the rotor core <NUM> on the iron loss.

In the present embodiment, since the adhesion part <NUM> is partially provided, the stress applied to the electrical steel sheet <NUM> due to curing shrinkage is reduced compared to a case in which the adhesion part <NUM> is provided on the entire surface.

A fast-curing type adhesive is cured in a short period of time at room temperature and has a smaller curing shrinkage than the thermosetting adhesive. Also, the influence of the strain of the electrical steel sheet <NUM> on the iron loss is larger in the tooth part <NUM> than that in the core back part <NUM>. Therefore, when the thermosetting adhesive is applied to the core back part <NUM> to form the second adhesion part 41b and the fast-curing type adhesive is applied to the tooth part <NUM> to form the first adhesion part 41a as in the present embodiment, increase in iron loss can be further suppressed.

Also, when the adhesion part is partially provided between the electrical steel sheets by combining a temporary adhesion using the fast-curing type adhesive that is cured in a short period of time and a main adhesion using the thermosetting adhesive that has a high mechanical strength after curing to cause the electrical steel sheets to be adhered, a stator core that combines high productivity, a high strength, low noise, and low vibration can be obtained.

An adhesion area ratio Q<NUM> of the adhesion part <NUM> to the electrical steel sheet <NUM> is preferably <NUM>% or more and <NUM>% or less, more preferably <NUM>% or more and <NUM>% or less, and still more preferably <NUM>% or more and <NUM>% or less. When the adhesion area ratio Q<NUM> is equal to or higher than the lower limit value of the above-described range, a mechanical strength of the laminated core is secured. When the adhesion area ratio Q<NUM> is equal to or lower than the upper limit value of the above-described range, an effect of suppressing the iron loss is more excellent.

Further, the adhesion area ratio Q<NUM> is a proportion of an area occupied by the adhesion part <NUM> (the adhesion region <NUM>) in the first surface of the electrical steel sheet <NUM> with respect to an area of the first surface of the electrical steel sheet <NUM>. Both the first adhesion part and the second adhesion part present on the first surface of the tooth part are included in calculating the adhesion area ratio Q<NUM>.

An adhesion area ratio QA0 of the adhesion part <NUM> to the core back part <NUM> is preferably <NUM>% or more and <NUM>% or less, more preferably <NUM>% or more and <NUM>% or less, and still more preferably <NUM>% or more and <NUM>% or less. When the adhesion area ratio QA0 is equal to or higher than the lower limit value of the above-described range, since the electrical steel sheets <NUM> adjacent to each other in the stacking direction can be adhered to each other with a sufficient adhesion strength, a rigidity of the stator core improves and noise characteristics are excellent. When the adhesion area ratio QA0 is equal to or lower than the upper limit value of the above-described range, an effect of suppressing the iron loss is more excellent.

Further, the adhesion area ratio QA0 is a proportion of an area occupied by the adhesion part <NUM> (the adhesion region <NUM>) in the first surface of the core back part <NUM> with respect to an area of the first surface of the core back part <NUM> of the electrical steel sheet <NUM>. Both the first adhesion part and the second adhesion part present on the first surface of the core back part are included in calculating the adhesion area ratio QA0. For example, when some of the first adhesion part 41a formed with the fast-curing type adhesive applied to the tooth part <NUM> is also present in the core back part <NUM>, the adhesion area ratio QA0 is calculated including that portion as well.

An adhesion area ratio QA1 of the first adhesion part 41a to the core back part <NUM> is preferably <NUM>% or more and <NUM>% or less, more preferably <NUM>% or more and <NUM>% or less, and still more preferably <NUM>% or more and <NUM>% or less. When the adhesion area ratio QA1 is equal to or higher than the lower limit value of the above-described range, a temporary fixing effect can be obtained. When the adhesion area ratio QA1 is not higher than the upper limit value of the above-described range, an effect of suppressing the iron loss is more excellent.

Further, the adhesion area ratio QA1 is a proportion of an area occupied by the first adhesion part 41a in the first surface of the core back part <NUM> with respect to the area of the first surface of the core back part <NUM> of the electrical steel sheet <NUM>.

An adhesion area ratio QA2 of the second adhesion part 41b to the core back part <NUM> is preferably <NUM>% or more and <NUM>% or less, more preferably <NUM>% or more and <NUM>% or less, and still more preferably <NUM>% or more and <NUM>% or less. When the adhesion area ratio QA2 is equal to or higher than the lower limit value of the above-described range, an effect of improving a rigidity of the laminated core can be obtained. When the adhesion area ratio QA2 is equal to or lower than the upper limit value of the above-described range, an effect of suppressing the iron loss is more excellent.

Further, the adhesion area ratio QA2 is a proportion of an area occupied by the second adhesion part 41b in the first surface of the core back part <NUM> with respect to the area of the first surface of the core back part <NUM> of the electrical steel sheet <NUM>.

An adhesion area ratio QB0 of the adhesion part <NUM> to the tooth part <NUM> is preferably <NUM>% or more and <NUM>% or less, more preferably <NUM>% or more and <NUM>% or less, and still more preferably <NUM>% or more and <NUM>% or less. When the adhesion area ratio QB0 is equal to or higher than the lower limit value of the above-described range, since the electrical steel sheets <NUM> adjacent to each other in the stacking direction can be adhered to each other with a sufficient adhesion strength, jumping of the tooth part can be suppressed, and thus a core shape is excellent. When the adhesion area ratio QB0 is equal to or lower than the upper limit value of the above-described range, an effect of suppressing the iron loss is more excellent.

Further, the adhesion area ratio QB0 is a proportion of an area occupied by the adhesion part <NUM> (the adhesion region <NUM>) in the first surface of the tooth part <NUM> with respect to an area of the first surface of the tooth part <NUM> of the electrical steel sheet <NUM>. Both the first adhesion part and the second adhesion part present on the first surface of the tooth part are included in calculating the adhesion area ratio QB0. For example, when some of the second adhesion part 41b formed with the thermosetting adhesive applied to the core back part <NUM> is also present on the tooth part <NUM>, the adhesion area ratio QB0 is calculated including that portion as well.

An adhesion area ratio QB1 of the tooth part <NUM> by the first adhesion part 41a is preferably <NUM>% or more and <NUM>% or less, more preferably <NUM>% or more and <NUM>% or less, and still more preferably <NUM>% or more and <NUM>% or less. When the adhesion area ratio QB1 is equal to or higher than the lower limit value of the above-described range, an effect of preventing the tooth part from being displaced can be obtained. When the adhesion area ratio QB1 is equal to or lower than the upper limit value of the above-described range, an effect of suppressing the iron loss is more excellent.

Further, the adhesion area ratio QB1 is a proportion of an area occupied by the first adhesion part 41a on the first surface of the tooth part <NUM> with respect to the area of the first surface of the tooth part <NUM> of the electrical steel sheet <NUM>.

An adhesion area ratio QB2 of the second adhesion part 41b to the tooth part <NUM> is preferably <NUM>% or more and <NUM>% or less, more preferably <NUM>% or more and <NUM>% or less, and still more preferably <NUM>% or more and <NUM>% or less. The adhesion area ratio QB2 may be <NUM>%. When the adhesion area ratio QB2 is equal to or lower than the upper limit value of the above-described range, an effect of suppressing the iron loss is more excellent.

Further, the adhesion area ratio QB2 is a proportion of an area occupied by the second adhesion part 41b on the first surface of the tooth part <NUM> with respect to the area of the first surface of the tooth part <NUM> of the electrical steel sheet <NUM>.

Between the electrical steel sheets <NUM> adjacent to each other in the stacking direction, a proportion (proportion P<NUM>) of an adhesion area of the first adhesion part 41a with respect to a total adhesion area of the adhesion part <NUM> is preferably <NUM>% or more and <NUM>% or less, and a proportion (proportion P<NUM>) of an adhesion area of the second adhesion part 41b with respect thereto is preferably <NUM>% or more and <NUM>% or less. Thereby, an effect of improving the mechanical strength, an effect of reducing noise and vibration, and an effect of suppressing the iron loss can be sufficiently obtained. Also, it is more preferable that the proportion P<NUM> be <NUM>% or more and less than <NUM>% and the proportion P<NUM> be <NUM>% or more and <NUM>% or less, it is still more preferable that the proportion P<NUM> be <NUM>% or more and <NUM>% or less and the proportion P<NUM> be <NUM>% or more and <NUM>% or less, it is particularly preferable that the proportion P<NUM> be <NUM>% or more and <NUM>% or less and the proportion P<NUM> be <NUM>% or more and <NUM>% or less, and it is most preferable that the proportion P<NUM> be <NUM>% or more and <NUM>% or less and the proportion P<NUM> be <NUM>% or more and <NUM>% or less. A sum of the proportion P<NUM> and the proportion P<NUM> is <NUM>%.

In calculating the adhesion area ratios Q<NUM>, QA0, QA1, QA2, QB0, QB1, and QB2, and the proportions P<NUM> and P<NUM>, an area of the adhesive marks obtained by an image analysis of the adhesive marks of the adhesion part <NUM>, the first adhesion part 41a, or the second adhesion part 41b after the electrical steel sheets <NUM> are broken away from each other is employed as an area of the adhesion region formed by each adhesion part.

In the present embodiment, it is preferable that the first adhesion part 41a have a dot shape with an average diameter of <NUM> or more and <NUM> or less, the second adhesion part 41b have a dot shape with an average diameter of <NUM> or more and <NUM> or less, the proportion P<NUM> be <NUM>% or more and less than <NUM>%, and the proportion P<NUM> be <NUM>% or more and <NUM>% or less. Also, it is more preferable that the first adhesion part 41a have a dot shape with an average diameter of <NUM> or more and <NUM> or less, the second adhesion part 41b have a dot shape with an average diameter of <NUM> or more and <NUM> or less, and the proportion P<NUM> be <NUM>% or more and less than <NUM>%, the proportion P<NUM> be <NUM>% or more and <NUM>% or less, the adhesion area ratio QB0 be <NUM>% or more and <NUM>% or less, and the adhesion area ratio QB1 be <NUM>% or more and <NUM>% or less.

The fast-curing type adhesive is one in which a monomer in a liquid state is instantly polymerized by a very small amount of moisture in the air or on a surface of an adherend to exhibit an adhesiveness.

As the fast-curing type adhesive, for example, a cyanoacrylate-based adhesive and an anaerobic adhesive can be exemplified. Of these, the cyanoacrylate-based adhesive known as an instant adhesive is preferable in terms of being excellent in fast-curing properties.

As the cyanoacrylate-based adhesive, an adhesive in which cyanoacrylate is polymerized and cured can be used without limitation. As the cyanoacrylate contained in the cyanoacrylate-based adhesive, for example, methyl cyanoacrylate, ethyl cyanoacrylate, methoxyethyl cyanoacrylate, butyl cyanoacrylate, and octyl cyanoacrylate can be exemplified. The cyanoacrylate contained in the cyanoacrylate-based adhesive may be one type or two or more types.

The thermosetting adhesive may be a one-component type or a two-component type.

As the thermosetting adhesive, for example, an epoxy resin-based adhesive, a phenol resin-based adhesive, and an unsaturated polyester resin-based adhesive can be exemplified. Of these, the epoxy resin-based adhesive is preferable from a viewpoint in which a stator core having a high mechanical strength can be easily obtained.

The epoxy resin-based adhesive contains an epoxy resin and a curing agent.

The epoxy resin is not particularly limited, and for example, a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a bisphenol AD type epoxy resin, an amine type epoxy resin, an alicyclic epoxy resin, a phenol novolac type epoxy resin, and a naphthalene type epoxy resin can be exemplified. Of these, the phenol novolac type epoxy resin is preferable from a viewpoint of application properties.

The curing agent contained in the epoxy resin-based adhesive may be one type or two or more types.

A glass transition temperature (Tg) of the epoxy resin is preferably <NUM> or higher and <NUM> or lower, more preferably <NUM> or higher and <NUM> or lower, and still more preferably <NUM> or higher and <NUM> or lower. When the Tg of the epoxy resin is equal to or higher than the lower limit value of the above-described range, a stator core having excellent heat resistance and high mechanical strength can be easily obtained. When the Tg of the epoxy resin is equal to or lower than the upper limit value of the above-described range, adhesion to the electrical steel sheet can be easily obtained.

Further, the Tg of the epoxy resin is a midpoint glass transition temperature measured by a differential scanning calorimetry (DSC) method according to JIS K <NUM>-<NUM>.

A number average molecular weight (Mn) of the epoxy resin is preferably <NUM> or more and <NUM> or less, more preferably <NUM> or more and <NUM> or less, and still more preferably <NUM> or more and <NUM> or less. When the Mn of the epoxy resin is equal to or more than the lower limit value of the above-described range, an adhesion strength can be easily increased. When the Mn of the epoxy resin is not more than the upper limit value of the above-described range, the epoxy resin-based adhesive becoming highly viscous is easily suppressed.

Further, the Mn of the epoxy resin can be measured by size-exclusion chromatography (SEC) described in JIS K <NUM>-<NUM>:<NUM> using polystyrene as a standard substance.

For the curing agent, a generally used thermosetting epoxy resin curing agent can be used. The curing agent is not particularly limited, and for example, an acid anhydride-based curing agent (phthalic anhydride, hexahydrophthalic anhydride, <NUM>-methylhexahydrophthalic anhydride, or the like), a phenol novolac resin, and dicyandiamide (DICY) can be exemplified. The curing agent contained in the epoxy resin-based adhesive may be one type or two or more types.

The phenol novolac resin is a novolak type phenol resin obtained by subjecting phenols (phenol or the like) and aldehydes (formaldehyde or the like) to a condensation reaction using an acid catalyst. As the curing agent, the phenol novolac resin is preferable from a viewpoint in which a stator core having a high mechanical strength can be easily obtained.

A curing agent content in the epoxy resin-based adhesive can be appropriately set according to types of curing agents, and for example, when a phenol novolac resin is used, <NUM> parts by mass or more and <NUM> parts by mass or less with respect to <NUM> parts by mass of the epoxy resin is preferable.

The epoxy resin-based adhesive may contain an acrylic resin in addition to the epoxy resin and the curing agent. An acrylic modified epoxy resin obtained by graft-polymerizing the acrylic resin on the epoxy resin may also be used.

The acrylic resin is not particularly limited. As monomers used for the acrylic resin, for example, unsaturated carboxylic acids such as acrylic acid and methacrylic acid, and (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, cyclohexyl (meth) acrylate, <NUM>-ethylhexyl (meth) acrylate, <NUM>-hydroxyethyl (meth) acrylate, and hydroxypropyl (meth) acrylate can be exemplified. Further, the (meth) acrylate means acrylate or methacrylate.

A number average molecular weight (Mn) of the acrylic resin is preferably <NUM> or more and <NUM> or less, more preferably <NUM> or more and <NUM> or less, and still more preferably <NUM> or more and <NUM> or less. When the Mn of the acrylic resin is equal to or more than the lower limit value of the above-described range, an adhesion strength can be easily increased. When the Mn of the acrylic resin is not more than the upper limit value of the above-described range, the epoxy resin-based adhesive becoming highly viscous is easily suppressed.

Further, the Mn of the acrylic resin can be measured by the same method as that in the Mn of the epoxy resin.

When the epoxy resin-based adhesive contains an acrylic resin, an acrylic resin content is not particularly limited, and can be, for example, <NUM>% by mass or more and <NUM>% by mass or less with respect to a total amount of the epoxy resin and the acrylic resin.

In the present embodiment, a plurality of electrical steel sheets forming the rotor core <NUM> are fixed to each other by fastening (dowel). However, the plurality of electrical steel sheets forming the rotor core <NUM> may also have a laminated structure fixed by an adhesive as in the stator core <NUM>.

Further, the laminated cores such as the stator core <NUM> and the rotor core <NUM> may also be formed by so-called turn-stacking.

The stator core <NUM> can be manufactured, for example, by repeating an operation in which the fast-curing type adhesive and the thermosetting adhesive are applied to a part of a surface of the electrical steel sheet <NUM>, the electrical steel sheet <NUM> is stacked on another electrical steel sheet, and then the electrical steel sheets are press-stacked to form the adhesion part <NUM> at room temperature (for example, <NUM> or higher and <NUM> or lower).

Curing of the applied fast-curing type adhesive progresses at room temperature, and the first adhesion part 41a is formed. Also, curing of the thermosetting adhesive progresses due to heating at the time of the press-stacking, and the second adhesion part 41b is formed.

Either the fast-curing type adhesive or the thermosetting adhesive may be applied first or they may be applied at the same time. Also, the fast-curing type adhesive and the thermosetting adhesive may be applied individually or may be applied in a mixed state.

Hereinafter, a method of manufacturing the stator core <NUM> using a manufacturing device <NUM> illustrated in <FIG> will be described.

First, the manufacturing device <NUM> will be described. In the manufacturing device <NUM>, while an electrical steel sheet P is sent in an arrow F direction from a coil C (hoop), the electrical steel sheet P is punched a plurality of times by a mold disposed at each stage to be gradually formed into a shape of the electrical steel sheet <NUM>, the fast-curing type adhesive and the thermosetting adhesive are applied to predetermined positions on a lower surface of a second and subsequent electrical steel sheets <NUM>, and the punched-out electrical steel sheets <NUM> are sequentially laminated and press-stacked while being heated.

As illustrated in <FIG>, the manufacturing device <NUM> includes a first stage punching station <NUM> at a position closest to the coil C, a second stage punching station <NUM> disposed adjacent to the punching station <NUM> on a downstream side in a conveying direction of the electrical steel sheet P, a first adhesive-coating station <NUM> disposed adjacent to the punching station <NUM> on a further downstream side, and a second adhesive-coating station <NUM> disposed adjacent to the first adhesive-coating station <NUM> on a further downstream side.

The punching station <NUM> includes a female mold <NUM> disposed below the electrical steel sheet P and a male mold <NUM> disposed above the electrical steel sheet P.

The first adhesive-coating station <NUM> and the second adhesive-coating station <NUM> respectively include an applicator <NUM> and an applicator <NUM> each having a plurality of injectors disposed according to a disposition pattern of the adhesion part <NUM> described above.

The manufacturing device <NUM> further includes a stacking station <NUM> at a position downstream of the second adhesive-coating station <NUM>. The stacking station <NUM> includes a heating device <NUM>, a fixed mold for outer shape <NUM>, a heat insulation member <NUM>, a fixed mold for inner shape <NUM>, and a spring <NUM>.

The heating device <NUM>, the fixed mold for outer shape <NUM>, and the heat insulation member <NUM> are disposed below the electrical steel sheet P.

The fixed mold for inner shape <NUM> and the spring <NUM> are disposed above the electrical steel sheet P.

In the manufacturing device <NUM> having the above-described configuration, first, the electrical steel sheet P is sequentially sent from the coil C in the arrow F direction of <FIG>. Then, punching processing by the punching station <NUM> is first performed with respect to the electrical steel sheet P. Next, punching processing by the punching station <NUM> is performed with respect to the electrical steel sheet P. Due to punching processing of these, a shape of the electrical steel sheet <NUM> having the core back part <NUM> and the plurality of tooth parts <NUM> illustrated in <FIG> is obtained in the electrical steel sheet P. However, since it is not completely punched out at this point, the processing proceeds to the next step in the arrow F direction.

In the first adhesive-coating station <NUM> of the next step, the fast-curing type adhesive is supplied from the injectors of the applicator <NUM> to be applied in a dot shape to a plurality of positions on a lower surface of the tooth part <NUM> of the electrical steel sheet <NUM>. Further, in the second adhesive-coating station <NUM>, the thermosetting adhesive is supplied from the injectors of the applicator <NUM> to be applied in a dot shape to a plurality of positions on a lower surface of the core back part <NUM> of the electrical steel sheet <NUM>.

Next, the electrical steel sheet P is sent to the stacking station <NUM>, punched out by the fixed mold for inner shape <NUM>, and laminated with high accuracy. For example, when a notch is formed at a plurality of positions on an outer circumferential end portion of the core back part and a scale is pressed against the notches from a side surface, the electrical steel sheets <NUM> can be prevented from being displaced and can be laminated with higher accuracy. At the time of the lamination, the electrical steel sheet <NUM> is heated to, for example, <NUM> or higher and <NUM> or lower by the heating device <NUM> while receiving a constant pressing force by the spring <NUM>. Curing of the thermosetting adhesive is accelerated by the heating.

The punching step, the application step, and the laminating step as described above are sequentially repeated, and thereby a predetermined number of electrical steel sheets <NUM> can be laminated via the partially provided adhesion part <NUM>.

The stator core <NUM> is completed by the above steps.

A method of manufacturing the stator core is not limited to the above-described method. For example, the thermosetting adhesive may be applied at the first adhesive-coating station <NUM>, and the fast-curing type adhesive may be applied at the second adhesive-coating station <NUM>. Also, at either or both of the first adhesive-coating station <NUM> and the second adhesive-coating station <NUM>, the thermosetting adhesive and the fast-curing type adhesive may be individually applied, and the thermosetting adhesive and the fast-curing type adhesive may be applied in a mixed state.

The adhesion part for causing the electrical steel sheets to be adhered to each other preferably includes two types of the first adhesion part formed with the fast-curing type adhesive and the second adhesion part formed with the thermosetting adhesive but may also include a third adhesion part formed with an adhesive in which the fast-curing type adhesive and the thermosetting adhesive are mixed. When the adhesion part for causing the electrical steel sheets to be adhered to each other includes the third adhesion part, the adhesion part may include only the third adhesion part or may include a combination of either or both of the first adhesion part and the second adhesion part and the third adhesion part.

A shape of the stator core is not limited to the form illustrated in the above-described embodiment. Specifically, dimensions of the outer diameter and inner diameter, a laminated thickness, and the number of slots of the stator core, a dimensional ratio of the tooth part in the circumferential direction and the radial direction, a dimensional ratio in the radial direction between the tooth part and the core back part, or the like can be arbitrarily designed according to desired characteristics of the electric motor.

In the rotor of the above-described embodiment, a set of two permanent magnets <NUM> forms one magnetic pole, but the present invention is not limited thereto. For example, one permanent magnet <NUM> may form one magnetic pole, or three or more permanent magnets <NUM> may form one magnetic pole.

In the above-described embodiment, the permanent magnetic electric motor has been described as an example of the electric motor, but a structure of the electric motor is not limited thereto as will be illustrated below, and furthermore, various known structures not illustrated below can also be employed.

In the above-described embodiment, the permanent magnetic electric motor has been described as an example of the electric motor, but the present invention is not limited thereto. For example, the electric motor may also be a reluctance motor or an electromagnet field motor (wound-field motor).

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

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

In the above-described embodiment, the motor has been described as an example of the electric motor, but the present invention is not limited thereto. For example, the electric motor may be a generator.

The stator core <NUM> can also be employed in a transformer instead of the electric motor <NUM>. In this case, a grain-oriented electrical steel sheet is preferably employed for the electrical steel sheet instead of the non-grain-oriented electrical steel sheet.

In addition, the components in the above-described embodiments can be appropriately replaced with well-known components within a range not departing from the meaning of the present invention, and the modified examples described above may be appropriately combined.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to the following description.

Fast-curing type adhesive (A-<NUM>): Cyanoacrylate-based adhesive (product name "Aron Alpha", manufactured by Toagosei Co.

Thermosetting adhesive (B-<NUM>): Epoxy resin-based adhesive (product name "ThreeBond", manufactured by ThreeBond Co. , Tg of epoxy resin: <NUM>).

A hoop having a composition for a non-grain-oriented electrical steel sheet containing <NUM>% by mass of Si, <NUM>% by mass of Al, and <NUM>% by mass of Mn was prepared. A thickness of the base steel was <NUM>. An insulation coating treatment agent containing a metal phosphate and an acrylic resin emulsion was applied to the hoop and baking was performed at <NUM> so that the hoop is coated with an insulation coating in a predetermined amount.

A stator core was fabricated by punching the hoop (electrical steel sheet) into a single-plate core which has a ring shape with an outer diameter of <NUM> and an inner diameter of <NUM> and to which <NUM> rectangular tooth parts <NUM> each having a length of <NUM> and a width of <NUM> are provided on an inner diameter side and then laminating it in sequence using the manufacturing device <NUM> having the configuration illustrated in <FIG> by the following procedures.

The hoop was sequentially sent in the arrow F direction of <FIG> from the coil C. Then, punching processing by the punching station <NUM> was first performed with respect to the hoop, and next, punching processing by the punching station <NUM> was performed with respect to the hoop. Due to punching processing of these, a shape of the electrical steel sheet <NUM> having the core back part <NUM> and the plurality of tooth parts <NUM> illustrated in <FIG> was formed in the hoop (punching step).

Next, the fast-curing type adhesive (A-<NUM>) was applied in a dot shape to predetermined positions on a lower surface (the first surface) of the tooth parts <NUM> of the hoop using the applicator <NUM> at the first adhesive-coating station <NUM>. Next, the thermosetting adhesive (B-<NUM>) was applied in a dot shape to predetermined positions on the lower surface (the first surface) of the core back part <NUM> of the hoop using the applicator <NUM> at the second adhesive-coating station <NUM> (application step).

Next, the hoop sent to the stacking station <NUM> was punched into a single-plate core by the fixed mold for inner shape <NUM> and then laminated while being pressurized (laminating step). At this time, the adhesive was heated to <NUM> by the heating device <NUM> to accelerate curing of the adhesive.

The punching step, the application step, and the laminating step described above were sequentially repeated to laminate <NUM> single-plate cores. An average diameter of the first adhesion part formed with the fast-curing type adhesive (A-<NUM>) between the electrical steel sheets <NUM> was <NUM>. An average diameter of the second adhesion part formed with the thermosetting adhesive (B-<NUM>) was <NUM>. The adhesion area ratios Q<NUM>, QA0, QA1, QA2, QB0, QB1, and QB2, and the proportions P<NUM> and P<NUM> were as shown in Table <NUM>.

A stator core was fabricated in the same manner as in example <NUM> except that average diameters, the adhesion area ratios Q<NUM>, QA0, QA1, QA2, QB0, QB1 and QB2, and the proportions P<NUM> and P<NUM> of the first adhesion part and the second adhesion part were as shown in Tables <NUM> and <NUM>.

The fast-curing type adhesive (A-<NUM>) was applied to the first surface of the tooth part in the same manner as in example <NUM> for a temporary adhesion, thereafter the metal steel sheets were entirely adhered to each other by being vacuum-impregnated with the thermosetting adhesive (B-<NUM>), and thereby a stator core having the adhesion area ratios Q<NUM>, QA0, QA1, QA2, QB0, QB1, and QB2 and the proportions P<NUM> and P<NUM> as shown in Table <NUM> was fabricated.

A stator core was fabricated in the same manner as in example <NUM> except that an adhesive used was only the fast-curing type adhesive (A-<NUM>), and the adhesion area ratios Q<NUM>, QA0, QA1, QA2, QB0, QB1, and QB2 and the proportions P<NUM> and P<NUM> were as shown in Table <NUM>.

A stator core was fabricated in the same manner as in example <NUM> except that an adhesive used was only the thermosetting adhesive (B-<NUM>), and the adhesion area ratios Q<NUM>, QA0, QA1, QA2, QB0, QB1, and QB2 and the proportions P<NUM> and P<NUM> were as shown in Table <NUM>.

The following evaluation was performed on the stator core of each example. The results are shown in Tables <NUM> and <NUM>.

After dropping the stator core from a height of <NUM>, a core strength was evaluated by measuring the number of sets of the electrical steel sheets in which a gap was generated between the electrical steel sheets among all the sets of the electrical steel sheets adjacent to each other in the stacking direction. When a distance between the electrical steel sheets was larger than that before the dropping, it was determined that a gap was generated between the electrical steel sheets. A smaller number of sets of the electrical steel sheets in which a gap was generated between the electrical steel sheets means higher core strength.

An outer circumferential end portion of the core back part of the stator core was vibrated in the radial direction by an impact hammer, and a modal analysis of noise and vibration was performed with a distal end of the tooth part and a central portion of the core back part in a direction of <NUM>° axially with respect to the vibration source as measurement points. Also, when a central portion of the core back part in the radial direction was vibrated in the axial direction by an impact hammer, a modal analysis of noise and vibration was performed with a distal end of the tooth part and a central portion of the core back part in a direction of <NUM>° axially with respect to the vibration source as measurement points. The evaluation was performed according to the following criteria. A smaller value means that more noise can be suppressed.

Stator iron loss was measured using a rotational iron loss-simulator having a rotor-shaped detector with a diameter of <NUM>. This rotational iron loss-simulator is one disclosed in <NPL>.

In evaluation of iron loss of the stator core, a fixed by fastening-stacking core having <NUM> laminated sheets in which eight adhesion parts were formed in the core back part and a fastening with a diameter of <NUM> was formed in a central portion of all the tooth parts was fabricated as a core serving as evaluation criteria. The stator core and the fixed by fastening-stacking core in each example were measured using the rotational iron loss-simulator, and the iron loss was evaluated according to the following evaluation criteria.

When the stator core was fabricated at <NUM> spm (the number of electrical steel sheets laminated in one minute was <NUM>) using the manufacturing device illustrated in <FIG>, a fixing state of the stator core taken out from the mold was checked and productivity of the stator was evaluated according to the following criteria.

Claim 1:
An adhesively laminated core (<NUM>) for a stator (<NUM>), in which a plurality of electrical steel sheets (<NUM>) are stacked to each other via a plurality of adhesion portions (<NUM>) disposed between the electrical steel sheets (<NUM>) adjacent to each other in a stacking direction, the adhesively laminated core (<NUM>) comprising:
the plurality of electrical steel sheets (<NUM>), wherein both surfaces of each of the plurality of electrical steel sheets (<NUM>) are coated with an insulation coating; and
the adhesion portion (<NUM>) which adheres the electrical steel sheets (<NUM>) to each other, wherein
all sets of the electrical steel sheets (<NUM>) adjacent to each other in the stacking direction are adhered by the plurality of adhesion portions (<NUM>),
each adhesion portion (<NUM>) is a cured adhesive without being divided,
the adhesive forming the adhesion portions (<NUM>) includes a fast-curing type adhesive (41a) and a thermosetting adhesive (41b),
the adhesion portions (<NUM>) are partially provided between the electrical steel sheets (<NUM>) adjacent to each other in the stacking direction,
each of the adhesion portions (<NUM>) includes a first adhesion part (41a) formed with the fast-curing type adhesive and a second adhesion part (41b) formed with the thermosetting adhesive,
the first adhesion part (41a) has an average diameter of <NUM> or more and <NUM> or less in a circular dot shape, the second adhesion part (41b) has an average diameter of <NUM> or more and <NUM> or less in a circular dot shape, and a proportion of an adhesion area of the first adhesion part (41a) is <NUM>% or more and less than <NUM>% and a proportion of an adhesion area of the second adhesion part (41b) is <NUM>% or more and <NUM>% or less with respect to a total adhesion area by the adhesion portion (<NUM>) between the electrical steel sheets (<NUM>), and
characterized in that an adhesion area ratio QB0 of the tooth part by the fast-curing adhesion portion (41a) is <NUM>% or more and <NUM>% or less and an adhesion area ratio QA0 of the core back part by the thermosetting adhesion portion (41b) is <NUM>% or more and <NUM>% or less between the electrical steel sheets (<NUM>).