JP2005130552A - Rotary electric machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary electric machine capable of suppressing occurrence of cogging torque and providing easily obtaining a core of perfect circle. <P>SOLUTION: A core body 3 of a motor comprises a plurality of split core bodies 3a, acquired by cutting a back yoke 1, to contain at least one tooth 2. Each split core body 3a receives a clamping force from a frame 6. At least a part of abutting surfaces A1, A2 of the split core bodies 3a, where adjoining split core bodies 3a abut against each other, is formed along the radial line, radially extending from the center axial line of a rotor. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a rotating electrical machine including a core in which a core body composed of a plurality of split core bodies formed by cutting a back yoke so as to include at least one tooth is integrated by a fastening force from a frame. .

Conventionally, in a large electric motor, in order to effectively use an electromagnetic steel sheet used for a stator core without waste, a stator core is manufactured from a divided core piece by, for example, the following procedure.
That is, using a large press machine, a thin magnetic steel sheet is punched to include at least one tooth to form a split core piece, and then the split core piece is laminated to form a split core body. Further, the plurality of divided core bodies are brought into contact with each other to form a ring-shaped core body. Thereafter, the cylindrical frame is heated and expanded, and the outer peripheral surface of the core body is covered with the frame, and then the frame and the core body are integrated by thermal contraction of the frame (see, for example, Patent Document 1).

JP 2001-95181 A

However, in the stator core manufactured by the split core piece, the contact surfaces of the adjacent split core bodies are inclined in the circumferential direction with respect to the radiation extending in the radial direction from the central axis of the core body. The split core body is mirror-asymmetric with respect to the line that bisects the width of the teeth, and the stress distribution caused by the thermal contraction of the frame is also asymmetric. As a result, the magnetic property distribution of the split core body is also asymmetric. There is a problem that cogging torque is generated due to the periodicity of the split core body having magnetic characteristics.
In addition, since the abutting surface is inclined in the circumferential direction, due to the tightening force from the frame, the adjacent split core bodies act in a direction away from each other in the radial direction, and a perfect circle of the core is obtained accordingly. There was also a problem that it was difficult.

  An object of the present invention is to solve the above-described problems, and an object of the present invention is to obtain a rotating electrical machine that can suppress the occurrence of cogging torque and that a perfect circle of a core is easily obtained. To do.

  In the rotating electrical machine according to the present invention, the core body is composed of a plurality of divided core bodies obtained by cutting the back yoke so as to include at least one tooth, and each divided core body is tightened from the frame. At least a part of the contact surface of the split core body where the adjacent split core bodies are in contact with each other is formed along the radiation extending radially from the central axis of the rotor.

  The rotating electrical machine according to the present invention can suppress the occurrence of cogging torque and improve the roundness of the core.

  Hereinafter, embodiments of the present invention will be described. In the drawings, the same or corresponding members and parts will be described with the same reference numerals.

Embodiment 1 FIG.
1 is a partial plan view of a core 5 of an electric motor according to Embodiment 1 of the present invention, FIG. 2 (a) is a partial sectional side view of the core body 3 in FIG. 1, and FIG. 1 (b) is a plan view of the core body 3. (C) is a plan view when a part of the core body 3 is developed linearly.
An electric motor that is a rotating electrical machine includes a stator and a rotor (not shown) that is provided inside the stator via a gap and forms a magnetic circuit with the stator.
The stator includes a core 5 and a winding (not shown) wound around the core 5.
The core 5 includes an annularly formed back yoke 1, a core body 3 including a tooth 2 protruding inward from an inner peripheral portion of the back yoke 1, and a cylindrical frame covering the outer peripheral surface of the core main body 3. 6.
The core body 3 is composed of a plurality of divided core bodies 3 a having a divided back yoke 1 a formed by cutting the back yoke 1 so as to include one tooth 2. Of the contact surfaces A1 and A2 where the adjacent substantially fan-shaped divided back yokes 1a and 1a contact each other, each linear portion A is located substantially along the radiation extending radially from the central axis of the rotor. ing.

The split core body 3a is composed of two types of first split core pieces 10 and second split core pieces 11 shown in FIGS. 3 (a) and 3 (b). In addition, in FIG. 3, the 1st division | segmentation core piece 10 and the 2nd division | segmentation core piece 11 are figures when it expand | deploys linearly.
The first divided core piece 10 has a substantially fan-shaped back yoke portion 12 and a teeth portion 13 extending from the back yoke portion 12 in the inner diameter direction. A joint portion 14 is provided on the right shoulder portion of the back yoke portion 12 so as to protrude in the vertical direction toward the back side of the paper surface in FIG.
The second divided core piece 11 has a substantially fan-shaped back yoke portion 15 and a teeth portion 16 extending from the back yoke portion 15 in the inner diameter direction. A joint portion 17 is provided on the left shoulder portion of the back yoke portion 15 so as to protrude in the vertical direction toward the back side of the paper surface in FIG.
Adjacent first divided core pieces 10 are in contact with each other to form a first core piece body 20, and adjacent second divided core pieces 11 are in contact with each other to form a second core piece body 21. Yes.
The split core main body 3a includes the first split core pieces 10 and the second split core pieces 11 alternately, and the projections of the joint portions 14 of the first split core pieces 10 are joints of the second split core pieces 11. The layers 17 are stacked in a state of being fitted into the recesses.

  In the electric motor having the above-described configuration, a plurality of adjacent divided core bodies 3a are brought into contact with each other to form a ring-shaped core body 3, and then the outer peripheral surface of the core body 3 is covered with a heated and expanded cylindrical frame 6; Thereafter, the core 6 is manufactured by integrating the frame 6 and the core body 3 by thermal contraction of the frame 6. That is, the core 5 is manufactured by “annealing” of the frame 6.

FIG. 4 is a stress contour diagram (region F in FIG. 1) as a result of calculation by the inventor of the stress state applied to the core body 3 as the frame 6 is cooled.
As the stress value, the Mises equivalent stress value most frequently used as the stress of the metal is shown. The value used was normalized by the maximum stress value in the calculation area.
In this embodiment, each of the straight portions A of the contact surfaces A1 and A2 where the adjacent substantially sector-shaped divided back yokes 1a and 1a contact each other is formed on the radiation extending in the radial direction from the central axis of the rotor. Therefore, as can be seen from the above calculation results, it can be seen that the compressive stress is acting in the direction perpendicular to the straight portion i, that is, in the circumferential direction. That is, in the magnetic flux path of the back yoke 1, the contraction fastening force from the frame 6 is effectively applied so that the magnetic gaps at the contact surfaces A1, A2 with which the divided back yokes 1a, 1a abut are less likely to occur. I can see that

In the core 5 of the electric motor according to this embodiment, each linear portion of the contact surfaces A1 and A2 between the adjacent divided core bodies 3a is substantially located on the radiation extending in the radial direction from the central axis of the rotor. The shape of the split core body 3a is substantially mirror-symmetric with respect to the center line of the tooth 2 (a line that bisects the width of the tooth 2). Therefore, the stress distribution in each divided core body 3a caused by the thermal contraction of the frame 6 is almost symmetric, and as a result, the magnetic characteristic distribution of the divided core body 3a is also almost symmetric. Therefore, in the electric motor in which the split core body 3a having this magnetic characteristic is incorporated, the generation of cogging torque is suppressed.
Further, the tightening force from the frame 6 acts in the circumferential direction on the split core body 3a, and a perfect circle of the core 5 is easily secured.

Further, the first core pieces 20 and the second core pieces 21 are alternately laminated, and the contact surfaces A1 and A2 of the split core body 3a are uneven in each layer in the lamination direction. Since it is formed, a part of the magnetic flux on the contact surfaces A1 and A2 can be a so-called “transition magnetic flux” that crosses the other divided core pieces 10 and 11 that contact in the stacking direction.
FIG. 5 is a diagram showing the state of the “crossover magnetic flux”. In FIG. 5, arrows C and D indicate magnetic fluxes flowing through the split core pieces 10 and 11 of the electric motor at a certain time. In addition to the normal magnetic flux flowing through the split core pieces 10 and 11, there is a transitional magnetic flux D. Show.
On the contact surfaces A1 and A2 of the split core main body 3a, although the magnetic resistance increases due to the slight gap, the stress received by cutting the magnetic steel plate, or the stress received when the frame 6 is contracted, the transition magnetic flux di As a result, an increase in the magnetic resistance of the core body 3 can be suppressed.

In addition, by making the contact surfaces of the adjacent divided core pieces different in three or more places in the stacking direction, the number of places where “crossover magnetic flux” is generated is increased, and the magnetic resistance of the core body 3 is further reduced. Also good.
Moreover, you may form the contact surface of a division | segmentation core main body in uneven | corrugated shape for every multilayer unit.
Further, with respect to the joint portions of the uppermost divided core piece and the lowermost divided core piece, the divided core pieces to be joined in the stacking direction are not necessary, and only the convex portion or the hole may be provided.
Also, when winding a wire by winding a conductor around the core body at a location on the innermost peripheral side of the contact surface of the split core body, round the portion so that the conductor is not damaged. You may do it.

Embodiment 2. FIG.
FIG. 6 is a partial plan view of the core 35 of the second embodiment. In this core 35, the Young's modulus of the frame 36 is set lower than that of the split core body 33a.
FIG. 7 is a diagram showing a calculation result of the stress applied to the split core body 33a by the thermal contraction of the frame 36 using Young's modulus, which is a mechanical characteristic of each of the split core body 33a and the frame 36, as a parameter. Similar to FIG. 4, the calculation model is the 1/4 symmetric model shown in FIG. 6, and the continuity condition is applied to the target surfaces α and β. This is obtained by imposing a condition that the displacement vector of the nodal point on the object plane α and the displacement vector of the symmetry plane β are 90-degree conversion type in the local coordinate system on each side.
The horizontal axis in FIG. 7 represents the ratio of Young's modulus of the frame 36 / Young's modulus of the split core body 33a, and the vertical axis represents the Mises equivalent stress value at the center of the split core body 33a for the split core body 33a that contacts the frame 36. The value obtained by averaging the data is normalized by the value in the case of a scale of 1.0 on the vertical axis.

As can be seen from FIG. 7, when the hardness of the frame 36 is higher than that of the split core body 33a, the stress applied to the split core body 33a increases, and when excessive stress is applied from the frame 36, the magnetic resistance of the split core body 33a increases. To do.
In this embodiment, the core 35 is set so that the Young's modulus of the frame 36 is lower than that of the split core main body 33a. Therefore, the stress applied to the split core main body 33a is suppressed, and the split back yoke 31a of the split core main body 33a is suppressed. The increase in magnetic resistance is suppressed, and the magnetic loss of the electric motor can be suppressed. For example, aluminum may be used as the material of the frame 36.

Embodiment 3 FIG.
FIG. 8 is a partial plan view of core 45 of the electric motor according to Embodiment 3 of the present invention.
In this embodiment, the recess 46a on the inner peripheral surface of the frame 46 are formed, the convex portion 43a ₁ which is formed at equal intervals on the outer surface of the split core body 43a in the recess 46a is engaged.
According to this electric motor, the recess 46a is engaged means between the frame 46 split core body 43a, is provided with the convex portion 43a _1, the core 45, it strongly binds with the frame 46 split core body 43a Is done.
As the engaging means, a convex portion may be formed on the inner peripheral surface of the frame, and this convex portion may be engaged with a concave portion formed at equal intervals on the outer surface of the divided back yoke.
Further, only one concave portion and convex portion may be provided in each of the frame and the core body, and the shape is not limited to the shape of the concave portion and convex portion.

Embodiment 4 FIG.
FIG. 9 is a side sectional view in the middle of manufacturing the core 55 of the electric motor according to Embodiment 4 of the present invention.
In this embodiment, the axial length of the frame 56 whose both ends are open ends is longer than the axial length of the core body 53.
According to the core 55 configured as described above, when the frame 56 is thermally contracted, both ends of the frame 56 are thermally contracted without being obstructed by the core body 53, so that the frame 56 extends inward from the outer peripheral edge of the core body 53. As a result, the frame 56 and the core main body 53 are more firmly fixed as compared with the first embodiment.

Embodiment 5.
FIG. 10 is a partial sectional side view of the core main body 63 according to the fifth embodiment of the present invention, FIG. 10B is a plan view of the core main body 63, and FIG. It is a top view.
In the first embodiment, the contact surfaces A1 and A2 between the adjacent divided core bodies 3a are displaced in the circumferential direction in a zigzag shape for each steel plate.
On the other hand, in the case of a magnet-type rotary electric motor having a rotor with a magnet attached to the outer peripheral surface, this magnet portion has the same effect as a gap portion of a magnetic circuit formed between the stator and the rotor. The value of the magnetic resistance due to the gap is very large even when compared with the magnetic resistance value when the gap between the contact surfaces A1 and A2 of the adjacent divided core main bodies 3a is several μm.
That is, as in the first embodiment, the contact having a larger stress value than the effect of “crossover magnetic flux” is expected in order to reduce the magnetic resistance due to the gap between the contact surfaces A1 and A2 of the split core body 3a. In some cases, it is important to reduce the area of the area near the surfaces A1 and A2 from the viewpoint of the magnetic characteristics of the core.
In this embodiment, from such a point of view, it is made in order to reduce the area of the vicinity region of the contact surface. Specifically, the contact surface A between the adjacent split core bodies 63a is set in the axial direction. Along the same plane.
According to the core of this embodiment, the region where the stress is large is not dispersed but is limited to the vicinity of the contact surface A. As a result, the magnetic resistance in the core is reduced and the magnetic characteristics are improved.

Embodiment 6 FIG.
FIG. 11 shows Embodiment 6 of the present invention, and shows a state in which a split core piece 71 is manufactured by punching a magnetic steel sheet.
The split core piece 71 including the back yoke portion 72 and the tooth portion 73 is made of a directional silicon steel plate. The split core piece 71 is punched so that the teeth 73 are substantially parallel to the easy axis direction of the directional silicon steel plate.
A grain-oriented electrical steel sheet is a steel sheet in which the direction in which a magnetic crystal is easily magnetized is arranged in parallel with the rolling direction, and has excellent magnetic properties in the rolling direction. For example, the test piece is parallel to the rolling direction, and KS C 4006 -1989 (or JIS C 2550-1986), as a result of the iron loss test, as a maximum value guaranteed at a magnetic flux density of 1.5 T and an operating frequency of 50 Hz, the thickness of the steel sheet is 0.5 [mm] The value is about 5.0 W / kg or less.
According to the core of this embodiment, since the magnetization easy axis of the electromagnetic steel sheet and the direction of the teeth portion 73 are the same direction, the interlinkage magnetic flux between the windings of the rotary motor can be increased, and the magnetic loss is reduced. Can be reduced.

In each of the above embodiments, the stator core surrounding the rotor has been described. Of course, the stator core is not limited to this, but can also be applied to an outer rotor type electric motor. That is, the present invention can also be applied to a rotor core that surrounds the stator.
In each of the above-described embodiments, the case where an electric motor is used as the rotating electrical machine has been described. However, the present invention can also be applied to a generator that is a rotating electrical machine.
The core body may be composed of a plurality of divided core bodies formed by cutting the back yoke so as to include two or more teeth.

It is a partial top view of the core of the electric motor of Embodiment 1 of this invention. (A) is a partial sectional side view of the core main body of FIG. 1, (b) is a partial plan view of the core main body, and (c) is a plan view when a part of the core main body is developed linearly. (A) is a top view when the 1st core piece which comprises the division | segmentation core main body of FIG. 1 is expand | deployed linearly, (b) is the 2nd core piece which comprises the division | segmentation core main body of FIG. It is a top view when a body is expand | deployed linearly. FIG. 2 is a stress distribution diagram of the core body of FIG. 1. It is a figure for demonstrating the "transition magnetic flux" produced between the 1st division | segmentation core piece of FIG. 1, and a 2nd division | segmentation core piece. It is a partial top view of the core of the electric motor of Embodiment 2 of this invention. It is the figure which showed about the stress which a division | segmentation core main body receives by the thermal contraction of a flame | frame using the Young's modulus of each division | segmentation core main body and a frame as a parameter. It is a partial top view of the core of the electric motor of Embodiment 3 of this invention. It is a sectional side view in the middle of manufacturing the core of the electric motor of Embodiment 4 of this invention. Partial sectional side view of the core body of the electric motor according to Embodiment 5 of the present invention, (b) is a partial plan view of the core body, and (c) is a plan view when a part of the core body is developed linearly. It is. In the electric motor of Embodiment 6 of this invention, it is a figure which shows a mode that a magnetic core is stamped and a division | segmentation core piece is manufactured.

Explanation of symbols

1 Back yoke, 2 teeth, 3, 53, 63 core body, 3a, 33a, 43a, 63a split core body, 4 slots, 5, 35, 45, 55 core, 6, 36, 46, 56 frames, 10, 30 1st division core piece, 11, 31 2nd division core piece, 12, 15 Back yoke part, 13, 16 Teeth part, 14, 17 Joint part, 31a, 43a ₁ convex part, 46a Concave part, 61, 71 Division Core piece, 72 Back yoke part, 73 Teeth part, A, A1, A2 Contact surface.

Claims (6)

An annular core, a stator including a winding around which a conducting wire is wound;
A rotor provided in the stator via a gap portion and forming a magnetic circuit together with the stator;
The core is formed by laminating a plurality of electromagnetic steel plates and covering an annular back yoke, a core main body made of teeth protruding inward from an inner peripheral portion of the back yoke, and an outer peripheral surface of the back yoke. A cylindrical frame,
The core body is composed of a plurality of split core bodies formed by cutting the back yoke so as to include at least one of the teeth, and each split core body receives a tightening force from the frame,
A rotating electrical machine in which at least a part of a contact surface of a split core body where adjacent split core bodies are in contact with each other is formed along radiation extending in a radial direction from a central axis of the rotor.   The rotating electrical machine according to claim 1, wherein the contact surface is formed in an uneven shape along a lamination direction of the electromagnetic steel sheets.   The rotating electrical machine according to claim 1, wherein a Young's modulus of the frame is lower than a Young's modulus of the split core body.   The engagement means for preventing relative movement between the frame and the split core main body is provided between the inner peripheral surface of the frame and the outer peripheral surface of the core main body. The rotating electrical machine according to item 1.   The rotating electrical machine according to any one of claims 1 to 4, wherein the frame and the core body are integrated by annealing the frame.   The electromagnetic steel plate is a grain-oriented silicon steel plate, and the plurality of split core pieces constituting the split core main body are configured by a back yoke portion and a tooth portion, and the easy magnetization axis direction of the grain-oriented silicon steel plate. 6. The rotating electrical machine according to claim 1, wherein the tooth portion is formed by punching so that the teeth portion is substantially parallel to the rotating electrical machine.

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