Invention title: Adhesive laminated core for stator and rotary electric machine
Technical field
[0001]
The present invention relates to an adhesive laminated core for a stator and a rotary electric machine.
This application claims priority based on Japanese Patent Application No. 2018-235865 filed in Japan on December 17, 2018, and the contents thereof are incorporated herein by reference.
Background technology
[0002]
Conventionally, a laminated core as described in Patent Document 1 below has been known. In Patent Document 1 below, it is an object to improve the heat conduction performance in the stacking direction while ensuring the adhesive strength and electrical insulation between the electromagnetic steel sheets. Then, in order to solve this problem, it is a laminated core formed by laminating electromagnetic steel sheets having an insulating film on the surface, and an organic substance layer made of at least an adhesive organic substance exists between the electromagnetic steel sheets, and the organic substance layer is present. The structure is adopted in which the average thickness of the grain is 4 μm or less. The adhesive organic substance has a viscosity of 1.0 Pa · s or less at a temperature at which fluidity is required before the curing reaction. Further, the organic material layer is injected between the electrical steel sheets by a vacuum impregnation method.
Prior art literature
Patent documents
[0003]
Patent Document 1: Japanese Patent Application Laid-Open No. 2004-88970
Outline of the invention
Problems to be solved by the invention
[0004]
Electrical steel sheets and adhesive organic substances (hereinafter referred to as adhesive parts) have different coefficients of thermal expansion. Therefore, when the electrical steel sheets are simply bonded to each other as in Patent Document 1 and heated to cure the bonded portion, the bonded portion is thermally shrunk and compressive stress or tensile stress is applied to the electromagnetic steel sheet. When these stresses are applied to the electrical steel sheet, the magnetic properties of the laminated core may deteriorate. This deterioration in magnetic properties is more likely to appear when the electromagnetic steel sheet is thin and the adhesive portion is thick.
On the other hand, even in the case of a room temperature curing type adhesive, it shrinks during curing. Therefore, in both the thermosetting type and the room temperature curing type, shrinkage during curing may cause deterioration of magnetic properties.
[0005]
The present invention has been made in view of the above circumstances, and provides an adhesive laminated core for a stator capable of suppressing a decrease in magnetic properties due to shrinkage of an adhesive during curing, and a rotary electric machine provided with the adhesive laminated core for a stator. Is the subject.
Means to solve problems
[0006]
In order to solve the above problems, the present invention employs the following means.
(1) The adhesive laminated core for a stator according to one aspect of the present invention has a plurality of electrical steel sheets laminated to each other and both sides coated with an insulating coating, and a plurality of electrical steel sheets adjacent to each other in the stacking direction. Each of the above-mentioned electrical steel sheets is arranged in a dot shape and includes an adhesive portion for adhering each of the electrical steel sheets to each other, and the chemical component of each of the electrical steel sheets contains 2.5% to 3.9% Si in mass%. The average tensile elasticity of the bonded portion is 2500 MPa to 5000 MPa, the average thickness of each electrical steel sheet is t1 in units of mm, the average thickness of each bonded portion is t2 in units of μm, and the yield strength of each electrical steel sheet is When the average value is YP in the unit MPa, at least one of the condition A that satisfies the following equations 1, 2, and 3 and the condition B that satisfies the following equations 3, 4, and 5. Meet.
50 x t1-12 ≤ t2 ≤ 50 x t1-6 ... (Equation 1)
0.15 ≤ t1 ≤ 0.27 ... (Equation 2)
0.5 ≤ t2 ≤ 2.5 ... (Equation 3)
0.025 x YP-12 ≤ t2 ≤ 0.025 x YP-8 ... (Equation 4)
380 ≤ YP ≤ 540 ... (Equation 5)
Here, as the substance constituting the insulating film, for example, (1) an inorganic compound, (2) an organic resin, (3) a mixture of an inorganic compound and an organic resin, or the like can be adopted. Of these, when the insulating coating is (1) an inorganic compound or (3) a mixture of an inorganic compound and an organic resin, the deterioration of magnetic properties due to shrinkage of the adhesive during curing is remarkably suppressed. can.
[0007]
(2) In the embodiment described in (1) above, the following configuration may be adopted: only the condition A is satisfied, or both the condition A and the condition B are satisfied; the average plate thickness t1 is It is 0.20 mm to 0.25 mm; and the average thickness t2 is 1.0 μm to 2.0 μm.
(3) In the embodiment described in (1) above, the following configuration may be adopted: only the condition B is satisfied, or both the condition A and the condition B are satisfied; the average thickness t2 is 1. It is 0.0 μm to 2.0 μm; and the average value YP of the yield strength is 450 MPa to 500 MPa.
(4) In the embodiment according to any one of (1) to (3) above, each of the adhesive portions may contain at least one of an acrylic type and an epoxy type oil level adhesive as an oil component.
(5) In the embodiment according to any one of (1) to (3) above, each of the adhesive portions is a room temperature curable acrylic adhesive containing SGA made of an elastomer-containing acrylic adhesive. May be good.
(6) The rotary electric machine according to one aspect of the present invention includes the adhesive laminated core for a stator according to any one of (1) to (5) above.
The invention's effect
[0008]
According to each of the above aspects of the present invention, it is possible to provide an adhesive laminated core for a stator capable of suppressing a decrease in magnetic properties due to shrinkage of the adhesive during curing, and a rotary electric machine provided with the adhesive laminated core for a stator.
A brief description of the drawing
[0009]
FIG. 1 is a cross-sectional view of a rotary electric machine provided with an adhesive laminated core for a stator according to an embodiment of the present invention.
[Fig. 2] Fig. 2 is a side view of the laminated core for the same stator.
3 is a cross-sectional view taken along the line AA of FIG. 2 and is a diagram showing an example of a formation pattern of an adhesive portion in the adhesive laminated core for the same stator.
FIG. 4 is a side view of a manufacturing apparatus used to manufacture an embodiment of an adhesive laminated core for a stator.
FIG. 5 is a graph showing the relationship between the average thickness t1 of the electrical steel sheet and the average thickness t2 of the bonded portion in the same embodiment.
FIG. 6 is a graph showing the relationship between the average value YP of the yield strength of the electrical steel sheet and the average thickness t2 of the bonded portion in the same embodiment.
Mode for carrying out the invention
[0010]
Hereinafter, with reference to the drawings, the adhesive laminated core for the stator and the rotary electric machine provided with the adhesive laminated core for the stator according to the embodiment of the present invention will be described. In the present embodiment, an electric motor as a rotary electric machine, specifically an AC electric motor, more specifically a synchronous electric motor, and even more specifically, a permanent magnet field type electric motor will be described as an example. This type of electric motor is suitably used for, for example, an electric vehicle.
[0011]
As shown in FIG. 1, the rotary electric machine 10 includes a stator 20, a rotor 30, a case 50, and a rotary shaft 60. The stator 20 and rotor 30 are housed in a case 50. The stator 20 is fixed in the case 50.
In the present embodiment, the rotor 30 is an inner rotor type in which the rotor 30 is located inside the stator 20 in the radial direction as the rotary electric machine 10. However, as the rotary electric machine 10, an outer rotor type in which the rotor 30 is located outside the stator 20 may be adopted. Further, in the present embodiment, the rotary electric machine 10 is a 12-pole 18-slot three-phase AC motor. However, the number of poles, the number of slots, the number of phases, and the like can be changed as appropriate.
The rotary electric machine 10 can rotate at a rotation speed of 1000 rpm by applying an exciting current having an effective value of 10 A and a frequency of 100 Hz to each phase, for example.
[0012]
The stator 20 includes an adhesive laminated core for a stator (hereinafter referred to as a stator core) 21 and a winding not shown.
The stator core 21 includes an annular core back portion 22 and a plurality of teeth portions 23. Hereinafter, the central axis O direction of the stator core 21 (or core back portion 22) is referred to as an axial direction, and the radial direction of the stator core 21 (or core back portion 22) (direction orthogonal to the central axis O) is referred to as a radial direction. The circumferential direction of the stator core 21 (or core back portion 22) (direction that orbits around the central axis O) is referred to as a circumferential direction.
[0013]
The core back portion 22 is formed in an annular shape in a plan view of the stator 20 when viewed from the axial direction.
The plurality of tooth portions 23 project from the inner circumference of the core back portion 22 toward the inside in the radial direction (toward the central axis O of the core back portion 22 along the radial direction). The plurality of tooth portions 23 are arranged at equal angular intervals in the circumferential direction. In the present embodiment, 18 tooth portions 23 are provided at every 20 degrees of the central angle centered on the central axis O. The plurality of tooth portions 23 are formed to have the same shape and the same size as each other. Therefore, the plurality of tooth portions 23 have the same thickness dimension as each other.
The winding is wound around the teeth portion 23. The winding may be a centralized winding or a distributed winding.
[0014]
The rotor 30 is arranged inside 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 in an annular shape (annular ring) arranged coaxially with the stator 20. The rotating shaft 60 is arranged in the rotor core 31. The rotating shaft 60 is fixed to the rotor core 31.
The plurality of permanent magnets 32 are fixed to the rotor core 31. In this embodiment, a set of two permanent magnets 32 form one magnetic pole. The plurality of sets of permanent magnets 32 are arranged at equal angular intervals in the circumferential direction. In the present embodiment, 12 sets (24 in total) of permanent magnets 32 are provided at a central angle of 30 degrees about the central axis O.
[0015]
In this embodiment, an embedded magnet type motor is adopted as a permanent magnet field type motor. The rotor core 31 is formed with a plurality of through holes 33 that penetrate the rotor core 31 in the axial direction. The plurality of through holes 33 are provided corresponding to the arrangement of the plurality of permanent magnets 32. Each permanent magnet 32 ​​is fixed to the rotor core 31 in a state of being arranged in the corresponding through hole 33. The fixing of each permanent magnet 32 ​​to the rotor core 31 can be realized, for example, by adhering the outer surface of the permanent magnet 32 ​​and the inner surface of the through hole 33 with an adhesive. As the permanent magnet field type motor, a surface magnet type motor may be adopted instead of the embedded magnet type.
[0016]
Both the stator core 21 and the rotor core 31 are laminated cores. For example, as shown in FIG. 2, the stator core 21 is formed by laminating a plurality of electromagnetic steel sheets 40 in the laminating direction.
The product thickness (total length along the central axis O) of each of the stator core 21 and the rotor core 31 is, for example, 50.0 mm. The outer diameter of the stator core 21 is, for example, 250.0 mm. The inner diameter of the stator core 21 is, for example, 165.0 mm. The outer diameter of the rotor core 31 is, for example, 163.0 mm. The inner diameter of the rotor core 31 is, for example, 30.0 mm. However, these values ​​are examples, and the product thickness, outer diameter and inner diameter of the stator core 21, and the product thickness, outer diameter and inner diameter of the rotor core 31 are not limited to these values. Here, the inner diameter of the stator core 21 is based on the tip of the teeth portion 23 of the stator core 21. That is, the inner diameter of the stator core 21 is the diameter of a virtual circle inscribed in the tips of all the teeth portions 23.
[0017]
Each of the electromagnetic steel sheets 40 forming the stator core 21 and the rotor core 31 is formed, for example, by punching an electromagnetic steel sheet as a base material. As the electromagnetic steel sheet 40, a known electrical steel sheet can be used. The chemical composition of the electrical steel sheet 40 contains 2.5% to 3.9% Si, as shown below in units of mass%. The range other than Si is not particularly limited, but a good range in this embodiment is specified below. By setting the chemical composition in this range, the average value YP of the yield strength of each electrical steel sheet 40 can be set to 380 MPa or more and 540 MPa or less.
[0018]
Si: 2.5% to 3.9%
Al: 0.001% to 3.0%
Mn: 0.05% to 5.0%
Remaining: Fe and impurities
[0019]
In this embodiment, a non-oriented electrical steel sheet is used as the electrical steel sheet 40. As the non-oriented electrical steel sheet, a non-oriented electrical steel strip of JISC2552: 2014 can be adopted. However, as the electrical steel sheet 40, a grain-oriented electrical steel sheet may be used instead of the non-oriented electrical steel sheet.