Rotating electric machine

Abstract

Provided is a rotating electric machine comprising: a rotor comprising a rotor core configured by layering a plurality of steel plates in which an outer peripheral groove, a magnet hole with a magnet embedded therein, and a through hole on a q-axis are formed; and a stator. The rotor core includes m blocks, where m=2n or 2n-1. When a block disposed at the end on one side among the m blocks is regarded as a first stage, and a block disposed at the end on the other side is regarded as an m-th stage, the outer peripheral grooves of the blocks disposed from the first stage to an n-th stage are disposed at positions rotated by a rotation angle α in a first direction on the basis of the outer peripheral groove of the block of the first stage. The outer peripheral grooves of the blocks disposed from an (n+1)-th stage to the m-th stage when m=2n or from the n-th stage to the m-th stage when m=2n-1 are disposed at positions rotated by the rotation angle α in a second direction opposite the first direction on the basis of the outer peripheral groove of the block of the (n+1)-th stage when m=2n or the n-th stage when m=2n-1. The centers of the through holes of the blocks of the first stage and the m-th stage are provided at positions shifted by a rotation angle β in the first direction on the basis of the q-axis of each block. The centers of the through holes of the blocks of the n-th stage and the n+1-th stage when m=2n or the n-th stage when m=2n-1 are provided at positions shifted by the rotation angle β in the second direction on the basis of the q-axis of each block. The rotation angle α is larger than the rotation angle β.

Description

Rotating electrical machine

[0001] The present invention relates to a rotating electrical machine.

[0002] In the rotor of a rotating electrical machine, it is known that by adopting a skew structure in the rotor core, torque ripple is reduced and NV (vibration and noise) characteristics are improved. For example, Patent Document 1 below discloses a configuration of a rotor of a rotating electrical machine that achieves both torque ripple reduction and stress optimization by complicating the shape of the through holes in the rotor core.

[0003] International Publication No. 2024 / 142403

[0004] In view of the technique described in Patent Document 1, an object of the present invention is to provide a rotating electrical machine that achieves both reduction of torque ripple and improvement of NV characteristics.

[0005] A rotating electrical machine comprising a rotor provided with a rotor core formed by laminating a plurality of steel plates in which an outer peripheral groove, a magnet hole in which a magnet is embedded, and a through hole on the q-axis are formed, and a stator, wherein the rotor core includes m blocks, m = 2n or 2n - 1, when the block disposed at one end among the m blocks is regarded as the first stage and the block disposed at the other end is regarded as the m-th stage, the outer peripheral grooves of the blocks arranged from the first stage to the n-th stage are arranged at positions rotated by a rotation angle α in the first direction with respect to the outer peripheral groove of the block in the first stage, the outer peripheral grooves of the blocks arranged from the (n + 1)-th stage to the m-th stage when m = 2n or from the n-th stage to the m-th stage when m = 2n - 1 are arranged at positions rotated by the rotation angle α in the second direction, which is opposite to the first direction, with respect to the outer peripheral groove of the block in the (n + 1)-th stage when m = 2n or the n-th stage when m = 2n - 1, the centers of the through holes of the blocks in the first stage and the m-th stage are provided at positions shifted by a rotation angle β in the first direction with respect to the q-axis of each block, the centers of the through holes of the blocks in the n-th and (n + )-th stages when m = 2n or the n-th stage when m = 2n - 1 are provided at positions shifted by the rotation angle β in the second direction with respect to the q-axis of each block, and the rotation angle α is larger than the rotation angle β.

[0006] We can provide a rotating electric machine that achieves both reduced torque ripple and improved NV characteristics.

[0007] A diagram illustrating the configuration of the rotor core before pressurization according to the first embodiment of the present invention. A diagram illustrating the pin inserted into the through hole of the rotor core according to the first embodiment of the present invention. A diagram illustrating the configuration of the through hole of the rotor core according to the first embodiment of the present invention. A diagram illustrating the skew of the rotor core after pressurization according to the first embodiment of the present invention. A diagram illustrating the skew of the rotor core after pressurization according to the second embodiment of the present invention. A diagram illustrating the shape of the through hole according to a modified example of the present invention.

[0008] Embodiments of the present invention will be described below with reference to the drawings. The following description and drawings are illustrative for illustrating the present invention, and have been omitted and simplified as appropriate for clarity of explanation. The present invention can also be carried out in various other forms. Unless otherwise specified, each component may be singular or plural.

[0009] The positions, sizes, shapes, and ranges of the components shown in the drawings may not represent their actual positions, sizes, shapes, and ranges in order to facilitate understanding of the invention. Therefore, the present invention is not necessarily limited to the positions, sizes, shapes, and ranges disclosed in the drawings.

[0010] (First Embodiment and Overall Configuration) (Figure 1) An embodiment of the present invention will be described in conjunction with the explanation of the manufacturing process of the rotor of a rotating electric machine. In the following explanation, the direction of arrow L will be referred to as the first direction L, and the direction of arrow R will be referred to as the second direction R, with the first direction L and the second direction R being opposite to each other. Also, the direction of arrow A will be one side of the rotor core 1, and the direction of arrow B will be the other side of the rotor core 1. Furthermore, a rotating electric machine has a rotor and a stator. In the following explanation, the rotor core 1 of the rotor will be the main focus, but the stator of the rotating electric machine will not be shown or described.

[0011] The rotor core 1, which constitutes the rotor of a rotating electric machine, is constructed by stacking a plurality of blocks 10 in the direction of rotation, as shown in the figure. Each block 10 is made up of a plurality of steel plates 3 stacked in the axial direction, and a plurality of outer peripheral grooves 5 are formed on its outer peripheral surface. The steel plates 3 are provided with magnet holes 2 in which magnets are embedded, and through holes 4 formed on the q-axis of each block 10 for positioning each block 10 in the rotor core 1.

[0012] Figure 1(b) shows the positions of the outer periphery grooves 5 in each block 10 shown in Figure 1(a). The rotor core 1 is constructed by stacking m blocks 10 in the axial direction, but Figure 1 shows a configuration where m = 2n, i.e., an even number of blocks 10 are stacked. For example, the rotor core 1 is made up of six stacked blocks 10. In the manufacturing process, the skew angle of the rotor core 1 can be calculated by determining the position of the outer periphery grooves 5 of each block 10.

[0013] As shown in Figure 1(b), m = 2n, and when the block 10 located at one end of the 2n blocks 10 is considered the first layer, the outer periphery grooves 5 of the blocks 10 from the first layer to the nth layer are positioned rotated by an angle α in the first direction L relative to the outer periphery groove 5 of the first layer block 10. Furthermore, the outer periphery grooves 5 of the blocks 10 from the (n+1)th layer to the other end (m layer) are positioned rotated by an angle α in the second direction R, which is opposite to the first direction L, relative to the outer periphery groove 5 of the (n+1)th layer block 10. In addition, in the rotor core 1, the nth layer block 10 and the (n+1)th layer block 10 are not skewed relative to each other, and their respective outer periphery grooves 5 are in the same position. Thus, from the formation positions of the outer periphery grooves 5 of each block 10, it can be seen that each block 10 is stacked skewed by an angle α in the first direction L and the second direction R.

[0014] (Figure 2) Figures 2(a) and 2(b) are cross-sectional views illustrating the relationship between the through-holes 4 and the pins 6 inserted into the through-holes 4 during the manufacturing process of the rotor core 1, when a portion of the rotor core 1 is viewed in cross-section. Multiple blocks 10 are stacked in the axial direction, and the rotor core 1, with the skew angle shown in Figure 1(b), has pins 6 inserted into the through-holes 4 as shown in Figure 2(a). This causes the pins 6 to penetrate the rotor core 1. One end of the pins 6 is fixed to the fixing surface 7a of the fixing base 7 with a fixing member such as a bolt (not shown). The other end of the pins 6 may be fixed or positioned with a jig or the like (not shown). One pin 6 penetrates all of the through-holes 4 of the blocks 10 stacked in the axial direction.

[0015] As shown in Figure 2(a), with the pins 6 passing through the through holes 4 of all the blocks 10 and fixed to the base 7, the rotor core 1 (block 10) is pressed in the axial direction as shown in Figure 2(b). In Figure 2(b), the axial pressing of the rotor core 1 is illustrated with three arrows. Due to this pressing, the gaps between the multiple steel plates 3 (Figure 1) that make up the block 10 become smaller, so the height h1 of the rotor core 1 before pressing becomes a height h2 which is smaller than the height h1 after pressing.

[0016] When the rotor core 1 is pressurized, each block 10 stacked adjacent to each other in the axial direction experiences a different degree of load from the direction of pressurization due to the skew angle set on the rotor core 1 (see Figure 1), resulting in an uneven distribution of load on each block 10 in the axial direction. As a result, some of the blocks 10 rotate in a certain circumferential direction, shifting their position from the skew angle set before pressurization. Simultaneously, as shown in Figure 2(b), the pins 6 also deform due to the circumferential rotation caused by the misalignment.

[0017] As shown in Figure 2(b), for example, if the number of blocks 10 stacked in the axial direction is 2n, then when pressure is applied from the axial direction, the displacement of the nth and (n+1)th blocks 10 from the top will be greater than the displacement of the other blocks 10. In other words, in the skew setting of the rotor core 1, the block 10 that is set to be furthest from its rotational position in a particular circumferential direction with respect to the q-axis of a certain block 10 will experience the greatest displacement when pressure is applied. To put it another way, blocks 10 located towards the center in the axial direction will experience a greater displacement due to pressure than blocks 10 located towards the ends in the axial direction.

[0018] Due to the phenomenon that occurs when the rotor core 1 is pressurized, the rotation angle α of each block 10 set before pressurization changes, making it impossible to obtain the desired skew rotation angle α after pressurization. This can lead to a deterioration of NV characteristics and potentially fail to satisfy customer requirements. Therefore, in the embodiment of the present invention described later in Figure 3, the formation positions of the through holes 4 in each block 10 (steel plate 3) are made different for each step of the block 10 so that the desired skew angle can be maintained with high accuracy even after pressurization.

[0019] (Figure 3) As shown in Figure 3(a), in the steel plate 3, the center of the through hole 4 is formed at a position shifted by a predetermined rotation angle from the position of the q axis. Figure 3(a) shows, as an example, the center 4b of the through hole in the nth and n+1th stage blocks 10 of an even number (m=2n) of blocks 10 stacked in the axial direction as shown in Figure 2. Figure 3(b) is a diagram illustrating the formation position of the through hole 4 in the block 10 when the rotor core 1 is viewed from the axial direction, when m=2n blocks 10 made of steel plate 3 are stacked in the axial direction and the q axis positions of each block 10 are aligned.

[0020] In the rotor core 1, the centers 4a of the through holes in the first and 2nth layers of the axially stacked blocks 10 are located at a position shifted by a rotation angle β in the first direction L with respect to the q-axis of each block 10. The centers 4b of the through holes in the nth and (n+1)th layers of the 10 are located at a position shifted by a rotation angle β in the second direction R with respect to the q-axis of each block 10. Furthermore, the rotation angle α (Figure 1) is set to be greater than this rotation angle β.

[0021] (Figure 4) As shown above, for each block 10 having the configuration of the through hole 4 shown in Figure 3, if an even number of blocks 10, m = 2n, are stacked in the axial direction as shown in Figure 4(a), then the present embodiment can also be applied to the case where an odd number of blocks 10, m = 2n-1, are stacked in the axial direction as shown in Figure 4(b), since it is sufficient to have a desired skew angle such that the position of the q axis of each block 10 is symmetrical in the axial direction when viewing the rotor core 1 from the cross-sectional direction.

[0022] Figure 4(a) shows the q-axis position 11 of each block 10 after the rotor core 1 in Figure 1(b) has been pressurized from the axial direction. When m = 2n and the block 10 located at one end of the m blocks 10 is considered the first stage, the q-axis position 11 of the blocks 10 located from the first stage to the nth stage is a position rotated by an angle α in the first direction L, relative to the q-axis position 11 of the first stage block 10. Furthermore, the q-axis position 11 of the blocks 10 located from the (n+1)th stage to the other end (m stage) is a position rotated by an angle α in the second direction R, relative to the q-axis position 11 of the (n+1)th stage block 10.

[0023] Figure 4(b) illustrates the q-axis position 11 of each block 10 when m = 2n-1. When the block 10 located at one end of the m blocks 10 stacked in the axial direction is considered the first layer, the q-axis positions 11 of the blocks 10 from the first layer to the nth layer are positions rotated by an angle α in the first direction L relative to the q-axis position 11 of the first layer block 10. Similarly, the q-axis positions 11 of the blocks 10 from the nth layer to the other end (mth layer) are positions rotated by an angle α in the second direction R relative to the q-axis position 11 of the nth layer block 10. In this case, the center position of the through hole 4 in the nth layer block 10 is located at a position shifted by an angle β in the second direction R relative to the q-axis of that block 10.

[0024] As described above, the formation positions of the through-holes 4 in each block 10 differ for each stage with respect to the q-axis of each block 10. This ensures that when the rotor core 1 is subjected to pressure from the axial direction, the formation positions of the through-holes 4, which take into account the positional displacement, allow each block 10 to fall within an acceptable range from its pre-pressurized skew setting position. Therefore, a desired skew angle can be obtained. Furthermore, this not only reduces the torque ripple of the rotating electric machine and improves the NV characteristics, but also reduces noise generated during skew angle displacement in the manufacturing process, as skew angle displacement is eliminated.

[0025] (Second Embodiment) (Figure 5) The object of the present invention can also be realized in a rotor core 1 with a different number of block 10 layers and a different skew setting than that in Figure 4 described above. For example, Figures 5(a) and 5(b) show the q-axis position 11 of each block 10 when the number of blocks 10 stacked in the axial direction is odd, but the second embodiment has a different number of blocks 10 stacked in the axial direction than the configuration shown in Figure 4(b). In addition, the second embodiment has a configuration that includes a block 10 that is stacked with the most rotation in the first direction L, as well as a block 10 that is stacked with the most rotation in the second direction R. In such a configuration, it is sufficient to have a configuration that divides the rotor core 1 into three parts in the axial direction based on two blocks 10 whose skew directions are reversed. Also, Figure 5(a) illustrates the case where there are nine blocks 10, and Figure 5(b) illustrates the case where there are seven blocks 10.

[0026] In the second embodiment, among the m blocks (m layers) stacked in the axial direction, the block 10 that is most rotated in the first direction L is defined as the n1th layer block 10, and the block 10 that is most rotated in the second direction R is defined as the n2nd layer block 10. The relationship is 1 < n1 < n2 < m.

[0027] The blocks 10 arranged from the 1st to the n1th layer are stacked with the q-axis position 11 of each block 10 rotated by an angle α in the first direction L, relative to the q-axis position 11 of the 1st layer block 10. The blocks 10 arranged from the n1+1th layer to the n2nd layer are stacked with the q-axis position 11 of each block 10 rotated by an angle α in the second direction R, relative to the q-axis position 11 of the n1+1th layer block 10. The blocks 10 arranged from the n2+1th layer to the mth layer are stacked with the q-axis position 11 of each block 10 rotated by an angle α in the first direction L, relative to the q-axis position 11 of the n2+1th layer block 10.

[0028] Furthermore, the n1th and n1+1th stage blocks 10 are not skewed relative to each other, and their q-axis positions 11 are the same. Similarly, the n2nd and n2+1st stage blocks 10 are not skewed relative to each other, and their q-axis positions 11 are the same. In addition, the centers of the through holes 4 in the n1st and n1+1st stage blocks 10 are located at a position shifted by a rotation angle β in the second direction R relative to the q-axis of each block 10.

[0029] Here, the displacement of the block 10 after axial pressure is applied to the rotor core 1 is greater for the n1st and n1+1th stage blocks 10 than for the other blocks 10. In other words, if the block 10 that is rotated the most circumferentially after pressure is applied includes both the first direction L and the second direction R, the displacement of the block 10 closest to the side that is pressed from the axial direction will be the greatest. In such a case, the center of the through hole 4 in the n2nd and n2+1st stage blocks 10 does not necessarily have to be located at a position shifted by a rotation angle β from the q axis of each block 10 in the first direction L.

[0030] (Modified form) (Figure 6) The cross-sectional shape of the through-hole 4 in each of the blocks 10 described above is shown as a perfect circle from the viewpoint of the relationship with the cross-sectional shape of the pin 6 that is inserted through the through-hole 4, as well as from the viewpoint of ease of design and productivity, but the shape is not limited as long as it is a shape that the pin 6 can penetrate through the through-hole 4. Also, it is preferable for the through-hole 4 to be symmetrical from the viewpoint of ease of design and productivity, but it is not limited to this. The center 4c of the through-hole 4 can be any point equidistant from multiple lines or points that form the edge of the through-hole 4.

[0031] As shown in Figure 6(a), if the shape of the through-hole 4 is a perfect circle or a circular shape, the center of the perfect circle or circular shape is the center 4c of the through-hole 4. If the through-hole 4 has a line-symmetric shape with a radial axis of symmetry 12, the center 4c of the through-hole 4 can be any point on the axis of symmetry 12. Also, as shown in Figure 6(b), if the shape of the through-hole 4 is line-symmetric, the center 4c of the through-hole 4 can be any point on the axis of symmetry 12 of the line-symmetric shape.

[0032] Furthermore, as shown in Figure 6(c), the shape of the through-hole 4 is rectangular, with its shorter side being an arc shape, and a symmetry axis 12 provided along its longitudinal direction. Two straight sections 4d parallel to the symmetry axis 12 are provided as part of the shape of the through-hole 4, with the symmetry axis 12 in between. In this case, if the range from one end to the other end of the straight section 4d is defined as range C, then the center 4c of the through-hole 4 is on the symmetry axis 12 and is the point where the perpendicular line 4e of the straight section 4d intersects with the symmetry axis 12, and can be any point within range C.

[0033] The center 4c of such through-holes 4 can be positioned using known techniques such as laser measurement. Furthermore, the multiple through-holes 4 in the steel plate 3 do not all have to be the same shape. As described above, regardless of the shape of the through-holes 4, by making the formation positions of the through-holes 4 different in each steel plate 3 (block 10), it is possible to achieve both a reduction in torque ripple and an improvement in NV characteristics.

[0034] It should be noted that the present invention is not limited to the embodiments described above, and various modifications and combinations of other configurations can be made without departing from the spirit of the invention. Furthermore, the present invention is not limited to having all the configurations described in the embodiments described above, and may also include configurations in which some of those configurations are omitted.

[0035] 1. Rotor core 1a. Rotation axis hole 2. Magnet hole 3. Steel plate 4. Through hole 4a. Center of the 1st and 2nth stage through holes 4b. Center of the nth and n+1th stage through holes 4c. Center 4d. Straight section 4e. Perpendicular line 5. Outer groove 6. Pin 7. Fixing base 7a. Fixing surface 10. Block 11. Q-axis position 12. Axis of symmetry

Claims

1. A rotating electric machine comprising a rotor having a rotor core formed by laminating a plurality of steel plates having outer perimeter grooves, magnet holes in which magnets are embedded, and through holes on the q axis, wherein the rotor core comprises m blocks, m = 2n or 2n-1, and when the block located at one end of the m blocks is designated as the first stage and the block located at the other end is designated as the m stage, the outer perimeter grooves of the blocks arranged from the first stage to the nth stage are positioned rotated by an angle α in the first direction with respect to the outer perimeter groove of the first stage block, the outer perimeter grooves of the blocks arranged from the n+1th stage to the mth stage when m = 2n, or from the nth stage to the mth stage when m = 2n-1, are positioned rotated by an angle α in the second direction, which is opposite to the first direction, with respect to the outer perimeter groove of the n+1th stage when m = 2n, or the nth stage when m = 2n-1, The centers of the through holes in the first and m-th stage blocks are located at a position shifted by a rotation angle β in the first direction with respect to the q-axis of each block, and the centers of the through holes in the n and n+1 stage blocks when m = 2n, or the n-th stage block when m = 2n-1, are located at a position shifted by a rotation angle β in the second direction with respect to the q-axis of each block, and the rotation angle α is greater than the rotation angle β.

2. A rotating electric machine according to claim 1, wherein when m = 2n-1, the blocks arranged from the nth stage to the mth stage are stacked by rotating in the second direction by the rotation angle α with respect to the q-axis of the nth stage block.

3. A rotating electric machine according to claim 1, wherein the through hole has a line-symmetric shape with a radial axis of symmetry, and the center of the through hole lies on the axis of symmetry.

4. A rotating electric machine according to claim 3, wherein the through hole is circular in shape, and the center of the through hole is the center of the circular shape.

5. A rotating electric machine according to claim 2, wherein the block that is stacked with the most rotation in the first direction is the n1th block, the block that is stacked with the most rotation in the second direction is the n2nd block, and the relationship between them is 1 < n1 < n2 < m, the blocks arranged from the 1st to the n1st stage are stacked with rotations of α in the first direction with respect to the q axis of the 1st stage block, the blocks arranged from the n1+1th to the n2nd stage are stacked with rotations of α in the second direction with respect to the q axis of the n1+1th stage block, and the blocks arranged from the n2+1th to the mth stage are stacked with rotations of α in the first direction with respect to the q axis of the n2+1st stage block.

6. A rotating electric machine according to claim 1, wherein a pin is passed through the through hole, and the blocks stacked in the axial direction through which the pin is passed are pressed in the axial direction.

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