JP6856011B2 - Rotating machine rotor - Google Patents

Description

The present invention relates to a rotor of a rotary electric machine.

In Patent Document 1 below, a rotor core formed by laminating a plurality of annular rotor core single plates made of electromagnetic steel plates, and a plurality of rotor cores embedded inside the rotor core at a predetermined distance in the circumferential direction. A rotor of a rotating electric machine provided with a permanent magnet, the rotor core single plate expands in a V shape in the circumferential direction around a central axis, a center bridge portion extending in the radial direction, and the center bridge portion. A pair of magnet insertion holes and a side bridge portion formed between the radial end of the magnet insertion holes and the outer circumference of the rotor core single plate are provided in the rotor core formed by laminating the rotor core single plates. Described is a rotor of a rotary electric machine in which a magnetic pole is formed by a permanent magnet embedded in the pair of adjacent magnet insertion holes.

Japanese Unexamined Patent Publication No. 2016-032340

In the rotor of a rotary electric machine described in Patent Document 1, a permanent magnet is embedded in a pair of magnet insertion holes adjacent in a V shape in the circumferential direction via a center bridge portion to form a magnetic pole. In order to reduce the torque ripple generated when the rotor rotates, a plurality of magnetic poles formed in the circumferential direction are formed to have the same shape.

On the other hand, as the material of the rotor core, an electromagnetic steel sheet rolled in one direction is usually used. This type of rolled steel sheet has anisotropy in strength depending on the angle from the rolling direction. A rotor of a rotary electric machine is required to have a rotor core having a center bridge portion and a side bridge portion having dimensions capable of withstanding centrifugal force from a permanent magnet generated when the rotor rotates.

In the current rotor core, no special consideration is given to the anisotropy of strength depending on the rolling direction of the above-mentioned electrical steel sheet, and in designing, the dimensions of the center bridge portion and the side bridge portion of the rotor core are the dimensions of the electromagnetic steel sheet used. It is usually set based on the strength at the position where the strength is the weakest. As a result, the widths of the center bridge and side bridges are larger than originally required, and as a result, the magnetic flux of the permanent magnets is prevented from flowing to the stator side more than necessary, which is the maximum. It is happening that the torque is also reduced. There is also a limit to the suppression of torque ripple.

The present invention has been made in view of the above circumstances, and the maximum torque can be increased by preventing the magnetic flux of the permanent magnet from flowing to the stator side more than necessary, and at the same time. An object of the present invention is to provide a rotor of a rotating electric machine capable of sufficiently suppressing torque ripple generated in the rotor when the rotor rotates.

The rotor of the rotary electric machine according to the present invention has a rotor core formed by laminating a plurality of annular rotor core single plates made of electromagnetic steel plates rolled in one direction, and a predetermined distance in the circumferential direction inside the rotor core. In the rotor of a rotary electric machine including a plurality of permanent magnets embedded at a distance, the rotor core single plate has a central axis, a center bridge portion in the radial direction, and a V shape in the circumferential direction about the center bridge portion. The center bridge portion includes a pair of magnet insertion holes that expand in a shape, and a circumferential side bridge portion formed between the radial end surface of the magnet insertion hole and the outer circumference of the rotor core single plate. Has a radial axis, the side bridge portion has a tangential axis orthogonal to the radial direction, and when the rolling direction of the electromagnetic steel plate is used as a reference axis, the reference axis and the center bridge portion are described. The larger the angle with the axis, the narrower the circumferential width of the center bridge portion, and the smaller the angle between the reference axis and the axis of the center bridge portion, the wider the circumferential width of the center bridge portion. The larger the angle between the reference axis and the tangential axis of the side bridge portion, the narrower the radial width of the side bridge portion, and the smaller the angle between the reference axis and the tangential axis of the side bridge portion. A wide radial width of the side bridge portion is formed, and a magnetic pole is formed by the permanent magnets embedded in the pair of adjacent magnet insertion holes in the rotor core formed by laminating the rotor core single plates. The plurality of rotor core single plates are sequentially laminated by shifting the phase in the circumferential direction by the same phase as the phase in which the magnetic poles are formed.

In the rotor of the rotary electric machine according to the present invention, the rotor core single plate constituting the rotor has its center bridge portion and side bridge portion, respectively, in consideration of the anisotropy of the strength depending on the rolling direction of the electromagnetic steel plate which is the material. , It is formed with different dimensions that can withstand the centrifugal force of the permanent magnet generated when the rotor rotates, and the plurality of rotor core single plates are shifted in the circumferential direction by the same phase as the phase of the formed electrodes. Are laminated. As a result, the magnetic flux of the permanent magnet is prevented from flowing to the stator side more than necessary, and the thickness in the radial direction at each position in the circumferential direction of the rotor core is also substantially made uniform, which is generated when the rotor rotates. It is also possible to suppress torque ripple. In addition, the maximum torque can be improved.

The schematic block diagram which shows the rotor of the rotary electric machine which concerns on embodiment of this invention seen from the direction along the rotation axis. The plan view which shows the rotor core single plate which comprises the rotor of a rotary electric machine. An enlarged view showing a part of FIG. It is a top view which shows the rotor core single plate, and is the figure for demonstrating the difference in the radial width of a side bridge part. A graph showing the relationship between the strength of an electromagnetic steel sheet and the angle from the rolling direction. It is a figure for demonstrating the state in which a plurality of rotor core single plates are laminated in the rotor of the rotary electric machine which concerns on this embodiment. The graph which shows the effect on the torque of the rotor of the rotary electric machine which concerns on this embodiment. The graph which shows the effect on the torque ripple of the rotor of the rotary electric machine which concerns on this embodiment.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

[Rotor]
FIG. 1 is a diagram showing a schematic configuration of a rotor of a rotary electric machine according to an embodiment of the present invention, and is shown when viewed from a direction along the rotation shaft 1a of the rotor. The rotor 1 is arranged to face the inner peripheral side of the stator (not shown) with a gap in the radial direction, and rotates relative to the stator. The rotor 1 includes a rotor core 2 and a plurality of magnetic poles 3 arranged on the rotor core 2. The rotor core 2 is formed by laminating a plurality of annular rotor core single plates 10 made of electromagnetic steel plates rolled in one direction.

The plurality of magnetic poles 3 are arranged at intervals (equally spaced) from each other along the circumferential direction of the rotor core 2. In the illustrated rotor core 2, eight magnetic poles 3 are formed at equal intervals with a phase of 45 degrees in the circumferential direction. The rotor core 2 is formed with a shaft fitting hole 4 on the inner peripheral side. The central axis of the shaft fitting hole 4 coincides with the rotating shaft 1a of the rotor. The rotor shaft 5 is press-fitted into the shaft fitting hole 4 and fixed integrally with the rotor core 2.

In each of the plurality of magnetic poles 3 described above, a pair of magnet insertion holes 3a and 3b are formed in a V shape in which the outer peripheral side of the rotor core 2 expands, and the permanent magnets 6a and 6b are magnet insertion holes 3a and 3b. One magnetic pole 3 is formed by being inserted into each of the magnets.

[Rotor core single plate]
As described above, the rotor core 2 is formed by laminating a plurality of annular rotor core single plates 10 made of electromagnetic steel plates rolled in one direction. FIG. 2 is a plan view of the rotor core single plate 10. The rotor core single plate 10 has a central axis 10a. The central shaft 10a coincides with the rotation shaft 1a of the rotor 1.

In this example, the rolling direction of the rolled electromagnetic steel plate as a material is the L direction, and a total of eight sets of the pair of magnet insertion holes 3a and 3b for inserting the permanent magnets 6a and 6b described above, that is, in the L direction. Two points symmetrically with the central axis 10a, four points symmetrically with respect to the central axis 10a in the N direction inclined at 45 degrees in the L direction, and the C direction (90 degree direction) orthogonal to the L direction. A total of eight pairs of magnet insertion holes 3a and 3b are formed at two points symmetrically on the central axis 10a. Hereinafter, the set formed in the L direction is referred to as a magnet insertion hole set 30A, the set formed in the N direction is referred to as a magnet insertion hole set 30B, and the set formed in the C direction is referred to as a magnet insertion hole set 30C. ..

[Center bridge]
In each of the magnet insertion hole sets 30A, 30B, and 30C, the magnet insertion hole 3a and the magnet insertion hole 3b have the same shape. The pair of magnet insertion holes 3a and magnet insertion holes 3b have a V-shape in which the outer peripheral side of the rotor core single plate 10 expands mirror-symmetrically with the radial axis 32 of the center bridge portion 31 extending in the radial direction as the axis of symmetry. , Arranged in the circumferential direction.

FIG. 3 shows a magnet insertion hole set 30A as a typical example. As described above, the center bridge portion 31a of the magnet insertion hole assembly 30A has a radial axis 32a, and the magnet insertion hole 3a and the magnet insertion hole 3b have a mirror-symmetrical posture with the radial axis 32a as the axis of symmetry. It is located at. When the rotor 1 rotates, the radial stress (centrifugal force) F1 caused by the permanent magnets 6a and 6b inserted into the magnet insertion hole assembly 30A mainly acts on the center bridge portion 31a. This also applies to the magnet insertion hole sets 30B and 30C.

When the L direction, which is the rolling direction of the rolled electromagnetic steel plate, is set as the reference axis L, the angle formed by the radial axis 32a of the magnet insertion hole assembly 30A with the reference axis L is 0 degrees, and as shown in FIG. The angle formed by the radial axis 32b of the magnet insertion hole assembly 30B with the reference axis L is 45 degrees, and the angle formed by the radial axis 32c of the magnet insertion hole assembly 30C with the reference axis L is 90 degrees.

As shown in FIG. 2, the circumferential width of the center bridge portion 31a in the magnet insertion hole assembly 30A is Wa, the circumferential width of the center bridge portion 31b in the magnet insertion hole assembly 30B is Wb, and the center in the magnet insertion hole assembly 30C. When the width of the bridge portion 31c in the circumferential direction is Wc, Wa> Wb> Wc in the rotor core single plate 10.

That is, as described above, since the stress F1 in the radial direction mainly acts on each center bridge portion 31 when the rotor 1 rotates, when the rolling direction (L direction) of the electromagnetic steel plate is set as the reference axis L, In the magnet insertion hole assembly 30C in which the angle between the reference axis L and the axis 32 of the center bridge portion 31 is the largest, that is, 90 degrees, the circumferential width Wc of the center bridge portion 31c is the narrowest, and the reference axis L and the center are centered. In the magnet insertion hole assembly 30A having the smallest angle with the axis 32 of the bridge portion, that is, 0 degrees, the circumferential width Wa of the center bridge portion 31a is the widest. In the magnet insertion hole assembly 30B in which the angle between the reference axis L and the radial axis 32b of the center bridge portion 31b is 45 degrees, the circumferential width Wb of the center bridge portion 31b is an intermediate width between the two. ..

[Side bridge part]
In each of the magnet insertion hole sets 30A, 30B, and 30C, a side bridge portion 34 exists between the magnet insertion hole 3a, the radial end 33 of the magnet insertion hole 3b, and the outer circumference 11 of the rotor core single plate 10. There is. As shown in FIGS. 2 and 3, in the illustrated example, the end portion 33 is an orthogonal plane in the tangential direction orthogonal to the radial direction, and the end portion 33 which is the orthogonal plane and the outer circumference 11 of the rotor core single plate 10 The space is the side bridge portion 34.

As shown in FIG. 3 showing the case of the magnet insertion hole set 30A, each side bridge portion 34 is provided with permanent magnets 6a, 6b inserted into the magnet insertion hole sets 30A, 30B, 30C when the rotor 1 rotates. The stress F2 acts mainly in the circumferential direction.

Each side bridge portion 34 has a predetermined length in the circumferential direction and has a tangential direction axis 35 orthogonal to the radial direction. In the illustrated rotor core single plate 10, the end portion 33 is an orthogonal plane in the tangential direction orthogonal to the radial direction, and here, the straight line passing through the end portion 33 corresponds to the tangential direction axis 35. If the end 33 is not an orthogonal plane in the tangential direction orthogonal to the radial direction, a straight line in any tangential direction is the tangential axis.

The end 33, which is one edge (inner edge) constituting the side bridge portion 34, is orthogonal to the radial direction as described above, and the outer circumference 11 of the rotor core single plate 10 which is the other edge (outer edge) is It is an arc. Therefore, the width H of the side bridge portion 34 in the radial direction changes in the circumferential direction. In the present embodiment, the average width of the widths that change in the circumferential direction is defined as the "radial width H of the side bridge portion".

In the present embodiment, the radial width of the side bridge portion 34a in the magnet insertion hole assembly 30A is Ha, the radial width of the side bridge portion 34b in the magnet insertion hole assembly 30B is Hb, and the side bridge in the magnet insertion hole assembly 30C. When the radial width of the portion 34c is Hc, Ha <Hb <Hc. That is, since the stress F2 in the circumferential direction mainly acts on the side bridge portion 34, the larger the angle formed by the reference axis L and the tangential axis 35 of each side bridge portion 34, the more the radial direction of the side bridge portion 34. The narrower the width and the smaller the angle between the reference axis L and the tangential axis 35 of the side bridge portion 34, the wider the radial width of the side bridge portion.

Specifically, as shown in FIG. 4, the angle formed by the reference axis L in the magnet insertion hole assembly 30A and the tangential axis 35a of the side bridge portion 34a is α1, and the reference axis L and the side bridge in the magnet insertion hole assembly 30B. When the angle formed by the tangential axis 35b of the portion 34b is α2 and the angle formed by the reference axis L in the magnet insertion hole assembly 30C and the tangential axis 35c of the side bridge portion 34c is α3, α1> α2> α3. Therefore, as described above, Ha <Hb <Hc.

In the magnet insertion hole assembly 30A and the magnet insertion hole assembly 30C, the width H in the radial direction of the side bridge portion 34 corresponding to the magnet insertion hole 3a and the side bridge portion 34 corresponding to the magnet insertion hole 3b is the same. is there. However, for example, as in the magnet insertion hole assembly 30B, the radial axis 32b is in the same direction (0 degree direction) or orthogonal to the reference axis L in the rolling direction (L direction) of the electromagnetic steel plate (90 degree direction). ), The tangential axis 35b1 and the tangential axis 35b2 are the reference axes L in the side bridge portion 34b1 corresponding to one magnet insertion hole 3a and the side bridge portion 34b2 corresponding to the other magnet insertion hole 3b. The angle α2 is different. In the actual design of the rotor core single plate 10, it is desirable to set the widths of both side bridge portions to the width Hb2 of the side bridge portion 34b2 whose angle α2 with respect to the reference axis L is smaller than that of the reference axis L.

[Characteristics of rolled steel sheet]
FIG. 5 is a graph showing the relationship between the strength of the electromagnetic steel plate and the angle from the rolling direction. When the strength in the rolling direction (L direction) is 100, the strength of the electromagnetic steel plate is orthogonal to it from the rolling direction. It gradually increases in the direction of 90 degrees. As described above, in the rotor core single plate 10 according to the present embodiment, the widths of the center bridge portion 31 and the side bridge portion 34 are set according to the strength while using the rolled steel plate having anisotropy in strength. ing.

That is, regarding the center bridge portion 31, the width W in the circumferential direction is the widest in the center bridge portion 31 extending in the rolling direction (L direction), and the width in the circumferential direction is wide in the center bridge portion 31 extending in the direction orthogonal to the rolling direction. W is set to be the narrowest, and for the side bridge portion 34, the radial width H is set narrower as the angle α formed by the tangential axis and the rolling direction (L direction) is larger, and the tangential axis and rolling are set. By setting the width H in the radial direction wider as the angle α formed by the direction (L direction) is smaller, compared with the rotor core single plate in which the center bridge part and the side bridge part are designed based on the conventional weakest part, When assembled as a rotor core, it is possible to reduce magnetic flux leakage of magnets in the center bridge portion 31 and the side bridge portion 34 as a whole.

[Manufacturing of rotor core]
The rotor core 2 is obtained by laminating a plurality of the above-mentioned rotor core single plates 10. For example, when stacking K number of rotor core single plates 10, the phase may be changed by 45 degrees for each plate, and as shown in FIG. 6A, K sheets may be 1/3 · K. It may be divided into groups of 1/6 sheets and laminated by shifting the phase by 45 degrees, respectively. As shown in FIG. 6 (b), the sheets may be divided into 6 groups of 1/6 and K sheets, and the phases may be shifted by 45 degrees each. May be laminated.

When the circumferential width of the center bridge portion and the radial width of the side bridge portion at each magnetic pole are different, the torque ripple may increase if the layers are laminated without changing the phase. In this example, the phases of the magnet insertion hole sets 30A, 30B, and 30C formed on the rotor core single plate 10 are shifted in the circumferential direction, and in this example, the phases are shifted by 45 degrees in the circumferential direction, and a plurality of magnets are inserted. The torque ripple can be reduced by sequentially laminating the rotor core single plates 10 of the above.

[Comparison with conventional rotor core]
The width of the center bridge portion in the circumferential direction of the rotor core according to the conventional design concept was set to W, the width of the side bridge portion in the radial direction was set to H, and the rotor core according to the present embodiment was compared. The schematic configuration of the overall shape of the rotor core is the same as that shown in FIG. In the rotor core based on the conventional design concept, the width in the circumferential direction of the center bridge portion in the magnet insertion hole set at the weakest part, that is, the part where the strength of the electromagnetic steel sheet is the weakest, the magnet corresponding to the magnet insertion hole set 30A in FIG. The width of the center bridge portion in the insertion hole set in the circumferential direction was set to W, and the width of the center bridge portion in the magnet insertion hole set 30B and the magnet insertion hole set 30C in the circumferential direction was also set to W.

The radial width H of the side bridge portion is also H in the radial width of the side bridge portion in the magnet insertion hole assembly corresponding to the magnet insertion hole assembly 30C in FIG. 2, and the magnet insertion hole assembly 30A and the magnet insertion hole assembly The radial widths of the side bridge portions at 30B were all set to H.

In the rotor core according to the present embodiment, the width of the center bridge portion in the circumferential direction and the width of the side bridge portion in the radial direction are set as shown in the following table.

Using the same material, a rotor core according to the conventional design concept and a rotor core according to the present embodiment were manufactured, and the same number of rotor cores were laminated to form a rotor core, and winding was applied to obtain a rotor. Each rotor was attached to a stator of the same standard to make a rotary electric machine. The maximum torque and torque ripple were measured by rotating the rotary electric machine according to the conventional structure and the rotary electric machine according to the present invention under the same conditions. The results are shown in FIGS. 7 and 8. FIG. 7 is a comparison when the maximum torque of the rotary electric machine according to the conventional structure is 100, and FIG. 8 is a comparison when the torque ripple of the rotary electric machine according to the conventional structure is 100.

In the rotary electric machine according to the present invention, as shown in FIG. 7, the maximum torque is relatively increased, and as shown in FIG. 8, the torque ripple is relatively small. This proves the superiority of the present invention.

1 ... Rotating machine rotor,
1a ... Rotating shaft of rotor,
2 ... Rotor core,
3 ... magnetic pole,
3a, 3b ... A pair of magnet insertion holes,
4 ... Shaft fitting hole,
5 ... Rotor shaft,
6a, 6b ... Permanent magnet,
10 ... An annular rotor core single plate made of rolled electromagnetic steel plate,
10a ... Central axis of rotor core single plate,
11 ... Outer circumference of rotor core single plate,
30 (30A, 30B, 30C) ... Magnet insertion hole assembly,
31 (31a, 31b, 31c) ... Center bridge portion extending in the radial direction,
32 (32a, 32b, 32c) ... Radial axis of the center bridge portion,
33 ... Radial end of magnet insertion hole,
34 (34a, 34b, 34c) ... Side bridge part,
35 (35a, 35b, 35c) ... Tangent axis of the side bridge,
L ... Reference axis, which is the rolling direction of the rolled electromagnetic steel sheet, which is the material.
W (Wa, Wb, Wc) ... Width of the center bridge in the circumferential direction,
H (Ha, Hb, Hc) ... Radial width of the side bridge,
F1 ... Radial stress (centrifugal force),
F2 ... Circumferential stress,
α (α1, α2, α3): The angle formed by the reference axis and the tangential axis of the side bridge portion.

Claims (1)

A rotor core formed by laminating a plurality of annular rotor core single plates made of electromagnetic steel sheets rolled in one direction, and a plurality of permanent magnets embedded inside the rotor core at a predetermined distance in the circumferential direction. In the rotor of a rotating electric machine equipped with
The rotor core single plate has a central axis, a center bridge portion in the radial direction, a pair of magnet insertion holes that expand in a V shape in the circumferential direction around the center bridge portion, and a radial direction of the magnet insertion holes. The center bridge portion has a radial axis, and the side bridge portion is orthogonal to the radial direction. Has a tangential axis and
When the rolling direction of the electromagnetic steel plate is used as a reference axis, the larger the angle between the reference axis and the axis of the center bridge portion, the narrower the circumferential width of the center bridge portion, and the reference axis and the center bridge. The smaller the angle of the portion with the axis, the wider the circumferential width of the center bridge portion.
The larger the angle between the reference axis and the tangential axis of the side bridge portion, the narrower the radial width of the side bridge portion, and the smaller the angle between the reference axis and the tangential axis of the side bridge portion. The width of the side bridge portion in the radial direction is formed wider.
A magnetic pole is formed by the permanent magnets embedded in the pair of adjacent magnet insertion holes in the rotor core formed by laminating the rotor core single plates.
The plurality of rotor core single plates are sequentially laminated by shifting the phase in the circumferential direction by the same phase as the phase in which the magnetic poles are formed.
Rotating electric machine rotor characterized by that.

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