JP2021002971A - Laminated core - Google Patents

Abstract

To provide a laminated core capable of reducing eddy current loss on a surface (inner peripheral surface of a slot) forming a slot among electrical steel sheets.SOLUTION: In a laminated core 1 in which electromagnetic steel sheets 2A and 2B having a plurality of teeth 4A and 4B arranged in parallel at equal or substantially equal pitches in a predetermined direction and slots 5 formed between teeth adjacent in a parallel direction 4X are laminated, in the laminated state, at least the inner peripheral surfaces of the slots 5iA and 5iB (the side end surfaces 5sA and 5sB of the slot, and the bottom surfaces 5uA and 5uB of the slot) of the electrical steel sheets are arranged so as to be uneven in the lamination direction.SELECTED DRAWING: Figure 3

Description

The present invention relates to a laminated core applicable to a motor or the like.

Conventionally, for example, a laminated core applied to a motor is generally formed by laminating electromagnetic steel sheets having the same shape in the same phase. Here, since the insulating film is peeled off and burrs are generated on the processed surface of the electrical steel sheet (the surface generated when the press is punched or the like), in the laminated core in which the electromagnetic steel sheet is laminated in the lamination direction, the surface is adjacent in the lamination direction. There is a risk that the machined surfaces of the matching electrical steel sheets will come into contact with each other and the electromagnetic steel sheets will be electrically short-circuited through the machined surfaces.

In such a laminated core, eddy current loss occurs when magnetic fluxes alternate in a short-circuited state. In particular, as the motor excitation frequency increases, the effect increases, which becomes a problem in high-speed motors and multi-pole motors having an excitation frequency of several hundred to several thousand Hz or more.

Further, even in a motor (skewed motor) in which each electromagnetic steel sheet is laminated by shifting the phase by a certain angle for the purpose of reducing torque ripple and the like, a short circuit cannot be avoided depending on the angle. In addition, skew itself may not be allowed depending on the type and specifications of the motor.

Patent Document 1 below discloses a configuration in which processed surfaces are individually insulatingly coated before laminating in order to prevent electrical short circuits between processed surfaces of electrical steel sheets.

Further, in Patent Document 2 below, as an electromagnetic steel sheet, one having a protruding portion protruding in the plate thickness direction at the tip of the tooth is applied, and a plurality of magnetic steel sheets are rotated by about 90 degrees to shift their positions. A configuration is disclosed in which a required number of teeth are laminated so that the teeth overlap each other, and a step is formed between the tips of the teeth of the electromagnetic steel sheets adjacent to each other in the stacking direction.

JP 2015-162912 Japanese Unexamined Patent Publication No. 2013-240183

However, in the case of the configuration described in Patent Document 1, a new treatment step for carrying out the insulating coating is required, and the cost is increased accordingly.

Further, in the configuration described in Patent Document 2, a step is provided on the tip surface of the teeth of the electromagnetic steel sheet adjacent to the stacking direction (the tip surface of the teeth that functions as a gap surface with the rotor), thereby causing an eddy current due to the magnetic flux of the motor. It is possible to suppress the current loss.

However, as the speed, miniaturization, and multipolarization of the motor increase, there is a high possibility that the eddy current loss on the surface other than the tip surface of the teeth, particularly the surface forming the slot (inner peripheral surface of the slot), cannot be overlooked. In particular, when the magnetic gap between the stator and the rotor (a narrow gap also called an air gap) is increased by increasing the speed of the motor, a part of the magnetic flux generated by the motor excitation passes through the slot and enters the slot. It is expected that the eddy current loss on the peripheral surface will increase.

The present invention has been made focusing on such a problem, and a main object thereof is to provide a laminated core capable of reducing eddy current loss on a surface forming a slot (inner peripheral surface of the slot). ..

That is, the laminated core according to the present invention is formed by laminating a plurality of teeth parallel to equal pitch or substantially equal pitch in a predetermined direction and an electromagnetic steel plate having slots formed between adjacent teeth in the parallel direction. It is characterized in that at least the inner peripheral surface of the slot, which is the surface of the electromagnetic steel sheet forming the slot in the laminated state, is arranged unevenly in the laminating direction.

In such a laminated core according to the present invention, since the inner peripheral surface of the slot of the electromagnetic steel sheet is laminated in a form having an uneven step in the laminating direction, a short circuit is unlikely to occur on the inner peripheral surface of the slot, and an eddy current is formed. The current loss can be reduced. Further, according to the laminated core according to the present invention, in order to reduce the eddy current loss on the inner peripheral surface of the slot, it is not required to apply the insulating coating after the press working, so that it is lower than the embodiment in which the insulating coating is applied. It is possible to reduce the cost.

In the laminated core according to the present invention, in order to more effectively prevent the occurrence of a short circuit on the inner peripheral surface of the slot and further reduce the eddy current loss, at least in the slot among the electromagnetic steel plates adjacent to each other in the laminating direction. A structure in which the peripheral surfaces are arranged unevenly in the stacking direction may be adopted.

In the present invention, as a preferable example of realizing a laminated core in which at least the inner peripheral surface of the slot, which is the surface forming the slot of the electrical steel sheet in the laminated state, is arranged unevenly in the stacking direction, each electrical steel sheet has the same shape. It has teeth, and an embodiment in which electromagnetic steel sheets adjacent to each other in the stacking direction are laminated in a state of being shifted by a predetermined phase in the parallel direction of the teeth in each electromagnetic steel sheet can be mentioned. Here, the "state shifted by a predetermined phase in the parallel direction of the teeth" means a state shifted by a predetermined angle in the parallel direction of the teeth if the parallel direction of the teeth is the circumferential direction.

Further, as another preferable example of realizing a laminated core in which at least the inner peripheral surface of the slot, which is the surface forming the slot of the electrical steel sheet in the laminated state, is arranged in an uneven shape in the lamination direction, each electrical steel sheet has a different shape2. It has more than one kind of teeth, and it can be mentioned that the electromagnetic steel sheets adjacent to each other in the stacking direction are laminated in a state where the teeth having different shapes are arranged in the stacking direction.

In particular, if the laminated core according to the present invention has a structure in which the tip surface of the teeth is unevenly arranged in the stacking direction in addition to the inner peripheral surface of the slot of the electromagnetic steel sheet in the laminated state, a short circuit on the tip surface of the teeth is unlikely to occur. , It is possible to further reduce the eddy current loss.

According to the present invention, since the inner peripheral surface of the slot of the electrical steel sheet is laminated in a form having an uneven step in the laminating direction, a structure in which a short circuit is unlikely to occur on the inner peripheral surface of the slot can be obtained, and eddy current loss is effective. It is possible to provide a laminated core that can be effectively reduced.

The figure which shows typically the plan view of the laminated core which concerns on one Embodiment (1st Embodiment) of this invention. The plan view of the electromagnetic steel plate in the same embodiment. FIG. 1 is an enlarged view of region a. FIG. 3 is a sectional view taken along line bb of FIG. The figure which shows typically the plan view of the laminated core which concerns on other embodiment (second embodiment) of this invention. The plan view of the electromagnetic steel plate in the same embodiment. FIG. 5 is an enlarged view of the c region of FIG. Enlarged view of d area of FIG. FIG. 7 is a cross-sectional view taken along the line EE of FIG. FIG. 7 is a cross-sectional view taken along the line ff of FIG.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
The laminated core according to the present embodiment can be applied as, for example, a stator constituting a rotating machine. The rotating machine is provided with a stator and a rotor arranged with a magnetic gap between the stators, and is suitably used as a motor capable of increasing speed, miniaturization, and multipolarization. Is.

The shape of the rotor is appropriately set according to the shape of the stator, the specifications of the motor, and the like, and detailed description thereof will be omitted. Hereinafter, the first embodiment and the second embodiment regarding the stator (laminated core) applicable to the inner rotor type motor in which the rotor is arranged inside (inner peripheral side) of the tubular stator will be described in order.

<First Embodiment>
The laminated core 1 according to the first embodiment has, for example, the shape shown in FIG. 1, and is formed by laminating a predetermined number of electromagnetic steel plates 2. As shown in FIG. 2, each electromagnetic steel plate 2 includes a substantially cylindrical yoke 3 and a plurality of (12 in the illustrated example) teeth 4 extending linearly inward from the inner peripheral surface of the yoke 3. It has one body. The tip surface 4t of the teeth 4 is set to have a larger (wider) dimension in the circumferential direction X than the other portions. In each electromagnetic steel plate 2, the direction in which the teeth 4 are lined up (the same direction as the circumferential direction X in this embodiment) is hereinafter referred to as the parallel direction 4X of the teeth 4. Each electrical steel sheet 2 has a slot 5 between the teeth 4 adjacent to each other in the parallel direction 4X of the teeth 4. The number and shape of the teeth 4 and slots 5 can be appropriately changed in design.

Such an electromagnetic steel sheet 2 is formed into a predetermined shape by punching with a press die or the like. Therefore, the tip surface 4t of the teeth 4, the bottom surface 5u of the slot 5, and the side end surface 5s are cut surfaces.

Here, burrs and sagging occur on the cut surface, and if such burrs and sagging overlap in a state where a predetermined number of electromagnetic steel sheets 2 are laminated, interlayer contact occurs, eddy current increases, and eddy current loss increases. However, it also leads to deterioration of motor performance.

Therefore, the laminated core 1 according to the present embodiment is shown in FIGS. 1, 3 and 4 (FIG. 3 is an enlarged view of the a region of FIG. 1, and FIG. 4 is a sectional view taken along line bb of FIG. 3). As shown, in the laminated state, at least the bottom surface 5u and the side end surface 5s of the slot 5 of the electromagnetic steel sheets 2 are arranged so as to be unevenly arranged in the stacking direction Y. Here, the bottom surface 5u and the side end surface 5s of the slot 5 are both slot inner peripheral surfaces 5i forming the inner circumference of the slot 5.

As shown in FIG. 3, the laminated core 1 according to the present embodiment is an electromagnetic steel sheet 2 adjacent to each other in the stacking direction Y when the electromagnetic steel sheets 2 having all the teeth 4 having the same shape in the parallel direction 4X at a predetermined pitch are laminated. The teeth 4 are shifted by a predetermined angle in the parallel direction 4X of the teeth 4, and inside the slots of the odd-numbered electrical steel sheet 2 (2A) slot inner peripheral surface 5i (5iA) and the even-numbered electrical steel sheet 2 (2B) in the stacking direction Y. The peripheral surface 5i (5iB) is set so as to be in a laminated state slightly deviated in the circumferential direction X. In FIG. 4, only the laminated state of three electromagnetic steel sheets 2 from the top surface of the laminated core 1 is extracted and shown, and the fourth and subsequent electrical steel sheets 2 are omitted.

The teeth 4 included in the laminated core 1 according to the present embodiment are teeth 4 (teeth without skew) that have uneven portions at predetermined intervals in the laminating direction Y but are substantially linear in the laminating direction Y. In the laminated core 1 according to the present embodiment, the tip surfaces 4t (4tA, 4tB) of the teeth 4 (4A, 4B) of the electromagnetic steel plates 2 (2A, 2B) adjacent to each other in the laminated direction Y in the laminated state are also in the circumferential direction X. Slightly offset (see FIGS. 1 and 3).

In such a laminated core 1 of the present embodiment, a winding (stator winding) (not shown) is provided in a slot 5 formed between teeth 4 arranged at equal pitches in the circumferential direction X. Then, a magnetic field is generated in the stator by supplying electric power to the stator windings, and the rotor is configured to rotate by the interaction between the magnetic field and the magnetic flux of the permanent magnet attached to the rotor.

Then, according to the laminated core 1 according to the present embodiment, in addition to the tooth tip surface 4t, an uneven step is formed on the slot inner peripheral surface 5i (5s, 5u), which is the surface forming the slot 5, in the stacking direction Y. Therefore, as compared with the configuration in which the slot inner peripheral surfaces 5i of the electromagnetic steel plates 2 adjacent to each other in the stacking direction Y are flush with each other, short circuits due to burrs and sagging are less likely to occur, and the slot inner peripheral surfaces 5i (5s, 5u) ), The eddy current loss can be reduced. In particular, when a magnetic flux passing through the slot is generated by motor excitation, the eddy current loss at the slot side end faces 5s (51s, 52s) can be reduced. In addition, according to the laminated core 1 according to the present embodiment, in order to reduce the eddy current loss on the slot inner peripheral surface 5i, it is not required to apply the insulating coating after the press working, so that the insulating coating is carried out after the press working. It is possible to reduce the cost as compared with the above mode. Further, in the laminated core 1 according to the present embodiment, since the laminated core 1 having the same shape can form an uneven step on the slot inner peripheral surface 5i (5s, 5u) in the stacking direction Y, several types of electromagnetic steel plates having different shapes can be formed. The cost can be reduced as compared with the case of laminating.

<Second Embodiment>
The laminated core 1 according to the second embodiment has the shape shown in FIG. 5, and is formed by laminating a predetermined number of electromagnetic steel plates 2 shown in FIG. Each electromagnetic steel sheet 2 integrally has a substantially cylindrical yoke 3 and a plurality of (12 in the illustrated example) teeth 4 extending linearly inward from the inner peripheral surface of the yoke 3. The point that the tip surface 4t of the teeth 4 is set wider than the other parts is the same as that of the electromagnetic steel plate 2 of the first embodiment, but the first embodiment is that a plurality of types of the shapes of the teeth 4 are set. It is different from the form of the electromagnetic steel plate 2.

That is, as shown in FIG. 6, each electrical steel sheet 2 in the second embodiment is set to a relatively small size with the first tooth 41 set to a relatively large size in the parallel direction 4X of the teeth 4. The second teeth 42 that have been made are arranged alternately. Further, since the shape of the slot 5 depends on the shape of the teeth 4 adjacent to each other in the parallel direction 4X, between the first teeth 41 and the second teeth 42 from the first teeth 41 to the second teeth 42 in the parallel direction 4X. A slot 5 (first slot 51) formed and a slot 5 (second slot) formed between the second teeth 42 and the first teeth 41 from the second teeth 42 to the first teeth 41 in the parallel direction 4X. The shape of 52) is also different.

The laminated core 1 according to the present embodiment is shown in FIGS. 5, 7 to 10 (FIG. 7 is an enlarged view of the c region of FIG. 5, FIG. 8 is an enlarged view of the d region of FIG. 5, and FIG. 9 is an enlarged view of the d region. 7 is a cross-sectional view taken along the line EE, and FIG. 10 is a cross-sectional view taken along the line ff of FIG. 7). As shown in FIG. 7), the shapes of the electromagnetic steel plates 2 adjacent to each other in the stacking direction Y are different from each other. Teeth 4 (first teeth 41 and second teeth 42) are laminated in a state of being overlapped and arranged in the stacking direction Y. Specifically, the even-numbered electrical steel sheets 2 (2B) are shifted in the circumferential direction X by one tooth (or a predetermined angle) with respect to the odd-numbered electrical steel sheets 2 (2A) in the stacking direction Y. It is laminated. Therefore, in the laminated core 1 according to the present embodiment, in the laminated state, the bottom surface 5u (51u, 52u) and the side end surface 5s (51s, 52s) of the slot 5 which is the inner peripheral surface of the slot of the electromagnetic steel plate 2 and the tip of the teeth. The surfaces 4t (41t, 42t) are arranged unevenly in the stacking direction Y.

The teeth 4 included in the laminated core 1 of the present embodiment are teeth 4 (teeth without skew) that have uneven portions at predetermined intervals in the laminating direction Y but are substantially linear in the laminating direction Y.

In such a laminated core 1, windings (stator windings) (not shown) are arranged in slots 5 formed between teeth 4 arranged at substantially equal pitches in the circumferential direction X. Then, a magnetic field is generated in the stator by supplying electric power to the stator windings, and the rotor is configured to rotate by the interaction between the magnetic field and the magnetic flux of the permanent magnet attached to the rotor.

Then, according to the laminated core 1 according to the present embodiment, in addition to the tooth tip surface 4t (41t, 42t), the slot inner peripheral surface 5i (51s, 51u, 52s, 52u), which is the surface forming the slot 5, is formed. Since there is an uneven step in the stacking direction Y, the slot inner peripheral surfaces 5i (51s, 51u, 52s) are aligned with each other in the slot inner peripheral surfaces 5i of the electromagnetic steel plates 2 adjacent to the stacking direction Y. , 52u), the eddy current loss can be reduced. In particular, as in the first embodiment, when a magnetic flux passing through the slot is generated by motor excitation, the eddy current loss at the slot side end surface 5s (51s, 52s) can be reduced. In addition, according to the laminated core 1 according to the present embodiment, it is not required to perform an insulating coating after the press working in order to reduce the eddy current loss on the slot inner peripheral surface 5i (51s, 51u, 52s, 52u). Therefore, the cost can be reduced as compared with the embodiment of the insulating coating. Further, as in the first embodiment, since the electromagnetic steel plate having the same shape can form an uneven step on the slot inner peripheral surface 5i (51s, 51u, 52s, 52u) in the stacking direction Y, several types of electromagnetic steel having different shapes can be formed. Compared with the case of laminating steel plates, the cost can be reduced.

In the first embodiment and the second embodiment, the laminated core 1 uses a positioning notch (recess) formed on the outer peripheral surface (outer peripheral surface of the yoke 3) of each electrical steel sheet 2 to be described above. The laminated state may be realized with high accuracy, or the above-mentioned laminated state may be realized by a stacking device or the like of an electromagnetic steel sheet 2 having no notch for positioning.

Although the embodiment of the present invention has been described above, the present invention is not limited to the configuration of the above embodiment. For example, in the above-described embodiment, the number, shape, and pitch of the teeth can be changed as appropriate, and for example, either an electromagnetic steel sheet having exactly the same pitch or an electromagnetic steel sheet having substantially the same pitch. It doesn't matter.

The outer edge shape of the electrical steel sheet may not be circular (the yoke is cylindrical) but polygonal (the yoke is square cylinder).

Further, in the present invention, for example, a first electromagnetic steel plate having the same shape of the teeth and a first electromagnetic steel plate having the same shape of the teeth and having a shape of the teeth different from the shape of the teeth of the first electromagnetic steel plate are the first. Two types of electrical steel sheets, two types of electrical steel sheets, are provided, and several types of electrical steel sheets with different shapes are laminated, such as alternately laminating a first electromagnetic steel sheet and a second electrical steel sheet in a direction in which the teeth substantially overlap in the laminating direction. Also includes the core. Even with such a laminated core, at least the inner peripheral surfaces of the slots of the electromagnetic steel sheets are arranged in an uneven shape in the laminating direction in the laminated state, and the eddy current loss on the inner peripheral surfaces of the slots can be reduced.

The present invention also includes a laminated core applicable to an outer rotor type motor in which the rotor rotates outward in the radial direction of the stator.

Further, the laminated core of the present invention may be applicable to a linear motor. In this case, the parallel direction of the teeth of each electrical steel sheet is the same as the traveling direction (moving direction) of the motor.

The laminated core of the present invention may have a form in which at least the inner peripheral surfaces of the slots of the electromagnetic steel plates are arranged in an uneven shape in the laminating direction in the laminated state, and only the end faces on the slot side of the inner peripheral surfaces of the slots are uneven in the laminating direction. It may be a form in which only the bottom surface of the slot is arranged in an uneven manner in the stacking direction among the inner peripheral surfaces of the slot. That is, the present invention includes a laminated core having a form in which only a part of the inner peripheral surface of the slot is arranged unevenly in the laminating direction, not the entire inner peripheral surface of the slot.

Further, the laminated core according to the present invention has a structure in which a plurality of adjacent (for example, 2 to 3) electromagnetic steel sheets are set as one set in a laminated state, and at least the inner peripheral surfaces of the slots are arranged unevenly in the stacking direction in each set. There may be.

In addition, the specific configuration of each part is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

1 ... Laminated core 2 ... Electromagnetic steel plate 4 ... Teeth 4t ... Teeth tip surface 4X ... Parallel direction 5 ... Slot 5i ... Slot inner peripheral surface

Claims (5)

It is a laminated core in which a plurality of teeth parallel to equal pitches or substantially equal pitches in a predetermined direction and electromagnetic steel plates having slots formed between the teeth adjacent to each other in the parallel direction are laminated.
A laminated core characterized in that at least the inner peripheral surface of a slot, which is a surface of the electromagnetic steel sheet forming the slot in a laminated state, is arranged in an uneven shape in the laminating direction. The laminated core according to claim 1, wherein at least the inner peripheral surfaces of the slots of the electromagnetic steel sheets adjacent to each other in the laminated direction are arranged in an uneven manner in the laminated direction. Each of the electrical steel sheets has the same shape of the teeth, and the electromagnetic steel sheets adjacent to each other in the stacking direction are laminated in a state of being shifted by a predetermined phase in the parallel direction of the teeth in each of the electrical steel sheets. The laminated core according to claim 1 or 2. Claim that each of the electromagnetic steel sheets has two or more types of the teeth having different shapes, and the electromagnetic steel sheets adjacent to each other in the stacking direction are laminated in a state where the teeth having different shapes are arranged in the stacking direction. The laminated core according to 1 or 2. The laminated core according to any one of claims 1 to 4, wherein the tip surfaces of the teeth of the electromagnetic steel sheets are arranged unevenly in the laminated direction in the laminated state.

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