JP2019103347A - Electric rotary machine - Google Patents

Abstract

To provide a rotary electric machine capable of reducing torque pulsation.SOLUTION: A rotor 3 includes a rotor core 31 and magnets 32 constituting 4*N magnetic poles. An angle formed between a center of a magnetic pole at a middle in a circumferential direction of an arbitrary magnet 32 and a center of a magnetic pole of the magnet 32 spaced by N pieces away from the magnet to one side in the circumferential direction around an axis of the rotor 3 in a cross section of the rotor 3 is less than 90 degrees. An angle formed between a center of a magnetic pole at the middle in the circumferential direction of an arbitrary magnet 32 and a center of a magnetic pole of the magnet 32 spaced by N pieces away from the magnet 32 to the other side in the circumferential direction is greater than 90 degrees.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a rotating electrical machine capable of achieving smooth rotation by reducing the pulsation of torque acting between a stator and a rotor.

  As a rotating electrical machine, there is known a rotating electrical machine having a stator having a stator core and a winding, and a surface magnet type rotor having a magnet attached to the outer peripheral surface of the rotor core. In such a rotating electrical machine, it is known that the forces generated between the magnet and the stator core and attracting each other are not always constant, but vary according to the rotation angle of the rotor. . In order to reduce the pulsation of the torque generated in the rotor, various methods are employed.

  As a representative example, techniques for skewing the magnets of the rotor are known. Further, in Patent Document 1, a plurality of magnetic poles continuous in the circumferential direction among the rotor magnets are regarded as one magnet group, and all the rotor magnets are divided by an even number of magnet groups including the same number of rotor magnets. A rotating electric machine in which magnet groups adjacent to each other in the circumferential direction are moved by the same angle in opposite directions in the circumferential direction from a state in which all the rotor magnets on the rotor are uniformly disposed in the circumferential direction Proposed.

  Further, Patent Document 2 proposes a rotor having a reluctance salient salient magnetic pole, in which the salient pole magnetic pole portion is made asymmetrical to reduce the pulsation of the generated torque.

JP, 2013-132154, A WO 2016/088698

  In the rotating electrical machine described in Patent Document 1, adjacent magnets are attached in a direction toward each other, so the magnets can not be brought closer to each other until the adjacent magnets hit, and the positions of the magnets attached in the circumferential direction are There is a problem that it is difficult to greatly reduce torque pulsations by largely shifting.

  In the rotating electrical machine described in Patent Document 2, the magnets are unevenly distributed in a part in the circumferential direction, so that the resultant force of the attraction between the magnets and the stator core is generated as a radial force, and the life of the rotor bearing is increased. It becomes a problem that it becomes early, causes abnormal noise and vibration. Further, with regard to a surface magnet type rotating electrical machine, a method for specifically reducing torque pulsation is not shown.

  The present invention has been made to solve the above-described problems, and an object thereof is to reduce the torque pulsation of the rotor and to obtain a rotating electrical machine that rotates smoothly.

The rotating electric machine according to the present invention is
In a rotating electrical machine comprising a stator and a rotor rotatably supported inside the stator,
The stator comprises a stator core and a coil wound around the stator core,
The stator core includes an annular yoke portion, and a plurality of teeth portions provided on the inner circumferential surface of the yoke portion at equal intervals in the circumferential direction and projecting radially inwards.
The rotor is disposed so as to extend in the axial direction of the rotor core at intervals from the rotor core and in the circumferential direction of the rotor core, and N is 2 or more A natural number) consisting of magnets that make up each magnetic pole,
Centering on the axis of the rotor in the cross section of the rotor,
The angle between the magnetic pole center at the circumferential direction of any of the magnets and the magnetic pole centers of the N magnets away from the magnet in one circumferential direction is less than 90 degrees,
The angle between the magnetic pole center at the circumferential direction center of the arbitrary magnet and the magnetic pole centers of the N magnets spaced apart from the magnet in the other circumferential direction is larger than 90 degrees.

According to the rotating electrical machine of the present invention,
The rotor is disposed so as to extend in the axial direction of the rotor core at intervals from the rotor core and in the circumferential direction of the rotor core, and N is 2 or more A natural number) consisting of magnets that make up each magnetic pole,
Centering on the axis of the rotor in the cross section of the rotor,
The angle between the magnetic pole center at the circumferential direction of any of the magnets and the magnetic pole centers of the N magnets away from the magnet in one circumferential direction is less than 90 degrees,
The torque pulsation of the rotating electrical machine is reduced because the angle between the magnetic pole center in the circumferential direction of the arbitrary magnet and the magnetic pole centers of the N magnets spaced apart from the magnet in the other circumferential direction is greater than 90 degrees. Can.

  In addition, since the stator of the rotating electrical machine targeted by the present invention is axially symmetric (rotational symmetry of 180 degrees), when the arrangement of the magnets of the rotor is configured by only a set symmetrical with respect to the rotational axis, The forces acting between the two magnets forming the symmetrical set and the stator cancel each other out. As a result, no mutually attractive forces are generated in the radial direction, and the life of the rotating electrical machine can be extended.

It is a cross-sectional schematic diagram perpendicular | vertical to the axial direction of the rotary electric machine which concerns on Embodiment 1 of this invention. It is a figure which shows the arrangement | positioning relationship of the magnet which concerns on Embodiment 1 of this invention. It is a graph which shows the torque of the rotary electric machine at the time of no load at the time of arrange | positioning a magnet equally to the circumferential direction. It is a graph which shows the torque of the rotary electric machine at the time of no load concerning Embodiment 1 of this invention. It is a graph which shows the torque of the rotary electric machine at the time of rated load at the time of arranging a magnet equally to the circumferential direction. It is a graph which shows the torque of the rotary electric machine at the time of the rated load concerning Embodiment 1 of this invention. It is a figure which shows the other example of arrangement | positioning of the magnet which concerns on Embodiment 1 of this invention. It is a cross-sectional schematic diagram perpendicular | vertical to the axial direction of the rotary electric machine which concerns on Embodiment 2 of this invention. It is a figure which shows the arrangement | positioning relationship of the magnet which concerns on Embodiment 2 of this invention. It is a figure which shows the arrangement | positioning relationship of the magnet which concerns on Embodiment 2 of this invention. It is a graph which shows the torque of the rotary electric machine at the time of no load at the time of arrange | positioning a magnet equally to the circumferential direction. It is a graph which shows the torque of the rotary electric machine at the time of no load concerning Embodiment 2 of this invention.

Embodiment 1
Hereinafter, a rotary electric machine according to Embodiment 1 of the present invention will be described with reference to the drawings.
In the present specification, the terms "axial direction", "circumferential direction", "radial direction" and "peripheral surface" are referred to respectively as "axial direction", "circumferential direction" and "diameter" of the rotor, unless otherwise noted. It shall mean "direction" and "peripheral surface".

FIG. 1 is a schematic cross-sectional view perpendicular to the axial direction of the rotary electric machine 100. As shown in FIG.
The rotary electric machine 100 includes a stator 2 and a rotor 3 rotatably supported inside the stator 2. The stator 2 comprises a stator core 21 and a coil 22. The stator core 21 is provided circumferentially at equal intervals on the inner peripheral surface of the annular yoke portion 21a and the yoke portion 21a. It consists of the teeth part 21b which protrudes in the direction inner side. The coil 22 is wound around the teeth 21 b.

  The rotor 3 has a cylindrical rotor core 31 present at the center of the rotor 3 and an outer peripheral surface of the rotor core 31 spaced apart from each other in the circumferential direction of the rotor core 31. It consists of 4 * N (N is a natural number of 2 or more, N = 3 in this embodiment) magnets 32 arranged to extend in the axial direction. The 4 · N magnets 32 are provided such that the poles of the magnets 32 adjacent to each other in the circumferential direction are reversed so that the magnetic poles thereof are alternately arranged in the circumferential direction of the rotor core 31. The fact that the number of magnets 32 is 4 · N means that N (three) magnets 32 are arranged at 90 degrees around the central axis of the rotor.

  The stator core 21 is made by laminating electromagnetic steel sheets having a thickness of 0.1 to 0.5 mm containing a large amount of silicon. The electromagnetic steel plates are connected in the laminating direction by extraction, caulking, welding, adhesion, etc., and an insulating layer is provided between the laminations to suppress generation of eddy current and to lose rotational torque due to heat generation of the stator 2 Can be reduced. The coil 22 of the stator 2 is composed of three phases of U phase, V phase and W phase, and is wound in the order of U phase, V phase and W phase on the teeth portion 21b adjacent in the circumferential direction, The same configuration is repeated six times in the circumferential direction.

  Now, assuming that the direction indicated by the arrow A in FIG. 1 is 0 degrees, the magnet 32 in which the pole center (center in the circumferential direction) is disposed at the position of 0 degrees is No. No. 1 toward the left side in the circumferential direction of the figure. 2, No. 3 · · No. Twelve magnets 32 are arranged in the order of twelve. The intervals between the circumferential end portions of the magnets 32 adjacent in the circumferential direction of the rotor core 31 are uneven depending on the location. 1 and No. The distance between the centers of 12 magnets 32 and No. 6 and No. The spacing between the circumferential ends of 7 is greater than the spacing between the circumferential ends of the other two adjacent magnets 32.

  FIG. 2 is a view showing an arrangement relationship of the magnets 32. Each magnet 32 when assuming that the magnet number of each magnet 32 of the rotor 3 of FIG. 1 and 12 magnets are equally arranged in the circumferential direction. The arrangement angle of the magnetic pole center (in FIG. 2, expressed as a uniform angle), the arrangement angle of the magnetic pole center of each magnet 32 in the present embodiment (in FIG. 2, expressed as an actual angle), and 12 magnets. The magnetic pole centers of the respective magnets 32 with respect to the magnitude of the angular deviation of the magnetic pole centers of the respective magnets 32 from the case where they are uniformly arranged in the directions and the axial center O of the rotor 3 in the cross section of the rotor 3 It is a figure which shows the angle which N pole left | separated from there (in this case N = 3 in this case) and the magnetic pole center of the magnet 32 to make make. The angles shown in the figure are rounded to the third decimal place.

  Generally, when magnets are uniformly arranged on the surface of rotor core 31 in the circumferential direction, the number of poles 4 · N (12 in the present embodiment) and the number of slots S 2 · M (this embodiment) In the embodiment, it is known that a torque pulsation having a cycle of an angle divided by 360 degrees is generated by the least common multiple L (36 in the present embodiment) of 18, where (M is a natural number)).

  In this embodiment, in order to cancel out the torque pulsations generated in the cycle of 360/36 = 10 degrees by the attraction forces generated between the magnets 32 and the stator 2, the following arrangement of the magnets 32 is provided. It is carried out.

  That is, for each magnet 32, an angle formed by the magnetic pole centers of the respective magnets 32 and the magnetic pole centers of the magnets 32 separated to the left by N pieces with respect to the axial center O of the rotor 3 in the cross section of the rotor 3 A half of the 360 / L degree (five degrees in the present embodiment) is deviated from the angle assuming that the magnets are evenly arranged in the circumferential direction.

  In FIG. 2, the angle between the magnetic pole centers of adjacent magnets 32 between magnet number 1 to magnet number 6 and between magnet number 7 to magnet number 11 is (90−5) / 3 = 28. I have 33 degrees. In this equation, "5" indicates 5 degrees, which is an angle half of the torque pulsation cycle. The angle between the magnetic pole centers of magnet No. 6 and magnet No. 7 and the angle between magnet No. 12 and magnet No. 1 are 38.33 degrees, and magnet 32 of magnet No. 1 and magnet No. 7 respectively. The angle formed by the center of the magnetic pole of the magnetic head is 180 degrees. In other words, the magnetic pole centers of the magnets 32 spaced apart by 2 · N in the circumferential direction are set to a position of 180 °, and the adjacent magnetic pole centers of 2 · N continuous magnets 32 in the circumferential direction are set. The interval between them is the same.

  When the magnets 32 are arranged as described above, No. 6 No. 1 magnet 32 and N pieces separated N to the left. The angle C1 between the magnetic pole centers of the four magnets 32 is 85 degrees. Similarly, all the “angles between the magnetic pole centers of the N magnets separated to the left” in FIG. 2 are plus 5 degrees or minus from 90 degrees assuming that the magnets are equally disposed in the circumferential direction. It is arranged to be 5 degrees. When attention is focused on the specific magnet 32, when the angle between the magnetic pole centers of the magnet 32 separated N from left and right is 95 degrees, which is plus 5 degrees, the magnetic poles of the magnet 32 separated from the other N The angle between the centers is 85 degrees, which is minus 5 degrees. As shown in FIG. 2, the above-mentioned plus 5 degrees and minus 5 degrees are interchanged in units of N from the magnet number 1.

  By setting the arrangement of the magnets 32 in this manner, the torque pulsations generated in the above-described cycle are less likely to be generated because the torques due to the magnetic forces generated mutually cancel each other among the magnets 32 separated by N in the circumferential direction. be able to.

  Next, torque pulsation generated between the rotor and the stator (at no load) in both the case where the magnets are arranged uniformly in the circumferential direction and the case where the magnets 32 are arranged as in the present embodiment Are compared using electromagnetic field analysis.

  FIG. 3 is a graph showing the torque of the rotating electrical machine at no load when the magnets are evenly arranged in the circumferential direction. The horizontal axis of the graph of FIG. 3 represents the rotational angle (mechanical angle) of the rotor, and the vertical axis represents the magnitude of the torque generated between the rotor and the stator. Since no load is connected to the rotating electrical machine, torque is only a component of torque pulsation. The broken line parallel to the horizontal axis represents the upper limit value and the lower limit value of the pulsating torque, and the curve drawn between the two broken lines represents the transition of the pulsating torque. The units on the vertical axis are relative units, and are the same units in FIG. 3 and FIG. 4 described next.

  As shown in FIG. 3, the pulsating torque between the rotor and the stator fluctuates in a cycle of approximately 10 degrees, and the fluctuation width (the width of the torque pulsation) is approximately 0.19. I understand.

  FIG. 4 is a graph showing the torque of the rotating electrical machine 100 at no load when the magnets 32 are unevenly arranged as described above. The horizontal axis of the graph of FIG. 4 represents the rotation angle (mechanical angle) of the rotor 3, and the vertical axis represents the magnitude of the torque generated between the rotor 3 and the stator 2. Since no load is connected to the rotating electrical machine 100, the torque is only the component of the torque pulsation. The broken line parallel to the horizontal axis represents the upper limit value and the lower limit value of the pulsating torque, and the curve drawn between the two broken lines represents the transition of the pulsating torque.

  As shown in FIG. 4, the torque pulsating between the rotor 3 and the stator 2 fluctuates in a cycle of approximately 20 degrees, and the fluctuation width (width of the torque pulsation) is set to plus or minus It turns out that it is 0.06.

  By comparing FIG. 3 and FIG. 4, the cycle of the torque pulsation which is a cycle of 10 degrees in FIG. 3 becomes 20 degrees, the fluctuation range decreases from 0.19 to 0.06, and the torque pulsation is reduced. You can see the effect of a 68% decrease.

  Next, torque pulsation generated between the rotor and the stator (during rated load) both in the case where magnets are uniformly arranged in the circumferential direction and in the case where magnets 32 are arranged as in the present embodiment Are applied to the stator coils and compared using electromagnetic field analysis.

  FIG. 5 is a graph showing the torque of the rotating electrical machine at rated load when the magnets are arranged evenly in the circumferential direction. The horizontal axis of the graph of FIG. 5 represents the rotation angle (mechanical angle) of the rotor, and the vertical axis represents the magnitude of the torque generated between the rotor and the stator. The broken line parallel to the horizontal axis represents the upper limit value and the lower limit value of the pulsating torque, and the curve drawn between the two broken lines represents the transition of the pulsating torque. The units of the vertical axis are relative units, and are the same units in FIG. 5 and FIG. 6 described next.

  As shown in FIG. 5, the pulsating torque between the rotor and the stator fluctuates between 1.76 and 1.95 in a cycle of approximately 10 degrees, and the fluctuation range of the torque is approximately 0.19. I understand that there is.

  FIG. 6 is a graph showing the torque of the rotary electric machine 100 at rated load when the magnets 32 are unevenly arranged as described above. The horizontal axis of the graph of FIG. 6 represents the rotation angle (mechanical angle) of the rotor 3, and the vertical axis represents the magnitude of the torque generated between the rotor 3 and the stator 2. The broken line parallel to the horizontal axis represents the upper limit value and the lower limit value of the pulsating torque, and the curve drawn between the two broken lines represents the transition of the pulsating torque.

As shown in FIG. 6, the torque pulsating between the rotor and the stator fluctuates between 1.70 and 1.84 in a cycle of approximately 20 degrees, and the fluctuation range of the torque is approximately 0.14. I understand that there is.
By comparing FIG. 5 and FIG. 6, the cycle of the torque pulsation which is a cycle of 10 degrees in FIG. 5 becomes 20 degrees, the fluctuation range decreases from 0.19 to 0.14, and the torque pulsation is 26% You can see the decreasing effect.

  In the above description, the magnetic pole centers of the magnets 32 spaced apart by 2 · N in the circumferential direction are set to be 180 degrees. Further, the intervals between the adjacent magnetic pole centers of 2 · N continuous magnets 32 in the circumferential direction are the same. By arranging in this manner, it is possible to reduce the magnetic flux flowing to the magnets 32 adjacent in the circumferential direction without passing through the stator core, and the torque constant of the rotary electric machine 100 can be further increased.

  In the above description, the angle between the magnetic pole centers of the two magnets 32 spaced apart in the circumferential direction is shifted by half of 360 / L degrees as compared with the case where the magnets are equally disposed in the circumferential direction. Although described, it is possible to obtain the same effect by approaching 180 / L degree, even if it is not strictly 180 / L degree.

FIG. 7 is a view showing another example of the arrangement of the magnets 32. As shown in FIG.
Even if the angle between the magnetic pole centers of the N magnets 32 arranged in the range of 90 degrees is set as shown in FIG. 3, the angle between the magnetic pole centers of the magnets 32 separated by N pieces is equal to the magnets. From 90 degrees assuming placement, it can be plus 5 degrees or minus 5 degrees. In addition, although the magnet 32 was demonstrated using the example arrange | positioned to the surface of the rotor core 31, until now, you may be embedded in the rotor core.

  According to rotary electric machine 100 according to the first embodiment of the present invention, torque pulsation of rotary electric machine 100 can be reduced. Further, since the stator 2 of the rotary electric machine 100 is axially symmetric (rotational symmetry of 180 degrees), when the arrangement of the magnets 32 of the rotor 3 is configured only with a set symmetrical with respect to the rotation axis, the symmetry is concerned. The forces acting between the two magnets 32 forming the set and the stator 2 cancel each other. For this reason, the forces mutually attracting in the radial direction are not generated, and the life of the rotary electric machine 100 can be extended.

Second Embodiment
Hereinafter, a rotary electric machine 200 according to Embodiment 2 of the present invention will be described focusing on differences from Embodiment 1.

FIG. 8 is a schematic cross-sectional view perpendicular to the axial direction of the rotary electric machine 200. As shown in FIG. The number of slots S2 of the stator 202 and the number of magnets 232 of the rotor 203 are different between the rotary electric machine 100 described in the first embodiment and the rotary electric machine 200 according to the present embodiment.
The rotary electric machine 200 includes a stator 202 and a rotor 203 rotatably supported inside the stator 202.
The stator 202 is composed of a stator core 221 and a coil 222. The stator core 221 is provided circumferentially on the inner peripheral surface of the annular yoke portion 221a and the yoke portion 221a, and is provided in the radial direction It consists of the teeth part 221b which protrudes inside. The coil 222 is wound around the teeth portion 221 b.

  The rotor 203 has a cylindrical rotor core 231 existing at the center of the rotor 203 and an outer peripheral surface of the rotor core 231 at intervals in the circumferential direction of the rotor core 231. It consists of 4 * N (N is a natural number of 2 or more, N = 10 in this embodiment) magnets 232 arranged to extend in the axial direction. The 4 · N magnets 232 are provided such that the poles of the magnets 232 adjacent in the circumferential direction are different from one another so that the magnetic poles thereof are alternately arranged in the circumferential direction of the rotor core 231. The fact that the number of magnets 232 is 4 · N means that N (10) magnets 232 are disposed at 90 degrees around the central axis of the rotor.

  The stator core 221 is made by laminating electromagnetic steel sheets having a thickness of 0.1 to 0.5 mm containing a large amount of silicon. The electromagnetic steel plates are connected in the lamination direction by extraction, caulking, welding, adhesion, etc., and an insulation layer is provided between the laminations to suppress the generation of eddy current and to lose rotational torque due to heat generation of the stator 202. Can be reduced. The coil 222 of the stator 202 is composed of three phases of U phase, V phase and W phase, and U +, U-, U +, V +, V +, V-, V +, W +, W It is repeatedly wound in the order of-and W +, and four sets of the same configuration are repeated in the circumferential direction. Although U + and U- flow current of the same phase, the direction of the magnetic field of the stator generated is different due to the difference in the direction of the windings. V + and V- as well as W + and W- have the same relationship.

  Now, assuming that the direction indicated by the arrow B in FIG. 8 is 0 degrees, the magnet 232 whose magnetic pole center (center in the circumferential direction) is disposed at the position of 0 degrees is No. No. 1 toward the left side in the circumferential direction of the figure. 2, No. 3 · · No. 40 magnets 232 are arranged in the order of 40. The spacing between circumferential end portions of the magnets 232 adjacent in the circumferential direction of the rotor core 231 is uneven depending on the place.

  9 and 10 are diagrams showing the arrangement relationship of the magnets 232, assuming that the magnet numbers of the magnets 232 of the rotor 203 of FIG. 8 and 40 magnets are equally arranged in the circumferential direction. Positional angle of magnetic pole center of each magnet, arrangement angle of each magnet 232 in the present embodiment, and angular deviation of magnetic pole center of each magnet 232 from the case where it is assumed that 40 magnets are equally arranged in the circumferential direction The magnetic pole centers of the respective magnets 232 and N from the center of the magnet 232 with respect to the size of the magnetic pole, the angle between the magnetic pole centers of the magnets 232 adjacent on the left, and the axial center O of the rotor 3 in the cross section of the rotor 3 It is a figure which shows the angle which the distant (in this case N = 10) and the magnetic pole center of the magnet 232 make.

  In this embodiment, since the number of poles 4 · N is 40 and the number of slots 2 · M is 36, N = 10 and M = 18, and the least common multiple L = 360 of 4 · N and 2 · M. Therefore, it can be said that torque pulsation with a cycle of 360/360 = 1 degree is likely to occur.

  Therefore, in the present embodiment, in order to cancel the torque pulsation generated in a cycle of 1 degree by the attraction forces generated between each magnet 232 and stator 202, the following arrangement is performed for each magnet 232 ing.

  That is, for each magnet 232, it was assumed that the magnet was equally disposed in the circumferential direction, with the magnetic pole centers of the respective magnets 232 and the magnetic pole centers of the magnets 232 of the magnets 232 separated by N (N = 10) left and right It is offset by 0.5 degrees which is half of 1 degree from the angle.

  For example, as shown in FIGS. 9 and 10, the angle between the magnet 232 of the magnet No. 1 and the center of the magnetic pole of the magnet 232 of the magnet No. 11 separated by N (N = 10) to the left from the magnet No. The angle is 89.5 degrees, and it can be understood from the angle between the magnetic pole centers when assuming that the magnets are equally disposed in the circumferential direction, it is smaller by 0.5 degrees which is an angle half of the period of the torque pulsation. Similarly, the angle formed by the magnet 232 of the magnet No. 11 and the magnetic pole center of the magnet 232 of the magnet No. 21 separated N to the left is 90.5 degrees, which is half the angle of the torque pulsation cycle 0 It turns out that .5 degrees is large.

This relationship holds for all the magnets 232.
At this time, with the axis O of the rotor 203 at the cross section of the rotor 203 as the center,
The angle between the magnetic pole centers of two circumferentially adjacent magnets 232 is:
The magnetic pole centers of the magnet 232 of magnet No. 10 and the magnet 232 of magnet No. 11 are 9.5 degrees between the magnetic pole centers of the magnet 232 of magnet No. 20 and magnet No. 21 of the magnet No. 21. The magnetic pole centers of the magnet 232 of magnet No. 30 and the magnet 232 of magnet No. 31 are 9.5 degrees between the magnetic pole centers of the magnet 232 of magnet No. 40 and magnet No. 1 of magnet No. 40. The angle between the magnetic pole centers of the other adjacent magnets 232 is 9 degrees.
This is because the angle formed by the magnetic pole centers of the two adjacent magnets 232 is the smallest at two points symmetrical with respect to the center of the rotor 203, and two points at 90 degrees from these two points respectively. The angle formed by the magnetic pole centers of the two adjacent magnets 232 is the largest, and the angle formed by the magnetic pole centers of the other two adjacent magnets 232 is equal to the number of 360 ÷ magnetic poles.

  Next, torque pulsation generated between the rotor and the stator (at no load) in both of the case where the magnets are equally disposed in the circumferential direction and the case where the magnets 232 are disposed as in the present embodiment Are compared using electromagnetic field analysis.

  FIG. 11 is a graph showing the torque of the rotating electrical machine at no load when the magnets are arranged uniformly in the circumferential direction. The horizontal axis of the graph of FIG. 11 represents the rotation angle (mechanical angle) of the rotor, and the vertical axis represents the magnitude of the torque generated between the rotor and the stator. Since no load is connected to the rotating electrical machine, torque is only a component of torque pulsation. The broken line parallel to the horizontal axis represents the upper limit value and the lower limit value of the pulsating torque, and the curve drawn between the two broken lines represents the transition of the pulsating torque. The units on the vertical axis are relative units, and are the same units in FIG. 11 and FIG. 12 described next.

  As shown in FIG. 11, the torque pulsating between the rotor and the stator fluctuates in a cycle of approximately one degree, and the fluctuation range (the width of the torque pulsation) is approximately 1.80. I understand. In addition, since the fluctuation | variation of a torque generate | occur | produces periodically, in FIG. 11, only the range which the rotor 203 rotated 10 degree | times by mechanical angle is described.

  FIG. 12 is a graph showing the torque of the rotating electrical machine 200 at no load when the magnets 232 are unevenly arranged as described above. The horizontal axis of the graph of FIG. 12 represents the rotation angle (mechanical angle) of the rotor 203, and the vertical axis represents the magnitude of the torque generated between the rotor 203 and the stator 202. Since no load is connected to the rotating electrical machine 200, the torque is only a component of the torque pulsation. The broken line parallel to the horizontal axis represents the upper limit value and the lower limit value of the pulsating torque, and the curve drawn between the two broken lines represents the transition of the pulsating torque.

  In FIG. 12, the torque pulsation of 1 degree cycle when the magnets are evenly arranged in the circumferential direction disappears, the fluctuation range of torque decreases from 1.80 to 0.18, and the torque pulsation is 90%. You can see the decreasing effect.

  According to the rotating electrical machine according to the second embodiment of the present invention, the same effect as that of the first embodiment can be obtained. Further, by applying the present invention to a rotating electrical machine in which the number of magnets 232 and the number of coils 222 are larger than those of the first embodiment, it is possible to provide a rotating electrical machine 200 with less torque pulsation.

  In the present invention, within the scope of the invention, each embodiment can be freely combined, or each embodiment can be appropriately modified or omitted.

100,200 electric rotating machines, 2, 202 stators, 21, 221 stator cores,
21a, 221a yoke portion, 21b, 221b teeth portion, 22, 222 coil, 3, 203 rotor, 31, 231 rotor core, 32, 232 magnet,
L Least common multiple.

Claims (5)

In a rotating electrical machine comprising a stator and a rotor rotatably supported inside the stator,
The stator comprises a stator core and a coil wound around the stator core,
The stator core includes an annular yoke portion, and a plurality of teeth portions provided on the inner circumferential surface of the yoke portion at equal intervals in the circumferential direction and projecting radially inwards.
The rotor is disposed so as to extend in the axial direction of the rotor core at intervals from the rotor core and in the circumferential direction of the rotor core, and N is 2 or more A natural number) consisting of magnets that make up each magnetic pole,
Centering on the axis of the rotor in the cross section of the rotor,
The angle between the magnetic pole center at the circumferential direction of any of the magnets and the magnetic pole centers of the N magnets away from the magnet in one circumferential direction is less than 90 degrees,
The rotating electrical machine, wherein an angle formed by a magnetic pole center at the circumferential direction center of the arbitrary magnet and a magnetic pole center of N magnets spaced apart from the magnet in the other circumferential direction is larger than 90 degrees. The rotating electrical machine according to claim 1, wherein the arbitrary magnet may be any of N continuous magnets. Centering on the axis of the rotor in the cross section of the rotor,
A magnetic pole center of a magnet spaced N apart from the arbitrary magnet in the circumferential direction,
The rotating electrical machine according to claim 1 or 2, wherein an angle between the arbitrary magnet and the magnetic pole center of the N magnets spaced apart from each other in the circumferential direction is 180 degrees. At two points symmetrical with respect to the center of the rotor, the angle between the magnetic pole centers of two adjacent magnets is the smallest,
The angle formed by the magnetic pole centers of the two adjacent magnets is the largest at the two positions located at 90 degrees from the two positions,
The angle between the magnetic pole centers of the other two adjacent magnets is
The rotating electrical machine according to any one of claims 1 to 3, which is equal to the number of poles of a 360 ÷ rotor. When the least common multiple of the number of magnetic poles of the rotor and the number of slots of the stator is L,
Centering on the axis of the rotor in the cross section of the rotor,
The angle formed by the magnetic pole center of any of the magnets and the magnetic pole centers of N magnets spaced apart from the magnet in one circumferential direction is (90-360 / L / 2) degrees,
The angle between the magnetic pole center of the arbitrary magnet and the magnetic pole centers of N magnets spaced apart from the magnet in the other circumferential direction is (90 + 360 / L / 2) degrees. The rotating electrical machine according to any one of the items.

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