JP2014209847A - Permanent magnet dynamo-electric machine and electric power steering device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce cogging torque generated due to variations on the rotor side.SOLUTION: A protrusion 8 composed of a magnetic material and holding a permanent magnet 1 is provided at a part of a rotor core 2 in the direction of the axis of rotation. More than one region of different magnetic circuit design, due to change in the cross-sectional shape of a cross-section perpendicular to the rotating shaft 10 of the rotor 30 having the permanent magnet 1 and the rotor core 2, is provided in the direction of the axis of rotation of the rotor 30. An auxiliary groove 5 is provided in a partial region of a stator core 3 in the axial direction of the teeth. The region provided with the auxiliary groove 5 is a partial region for each region facing the region provided with the protrusion 8, and the region not provided with the protrusion 8.

Description

  The present invention relates to a permanent magnet type rotating electric machine using a permanent magnet as a field and an electric power steering apparatus using the same.

  In recent years, motors with small cogging torque have been required for various applications, for example, industrial servo motors and elevator hoisting machines. Focusing on the vehicle, an electric power steering device has been widely used to improve fuel efficiency and steering performance. The motor used in the electric power steering apparatus has a strong demand for reducing the cogging torque of the motor in order to obtain a smooth steering feeling because the cogging torque is transmitted to the driver via the gear. On the other hand, as a technique for reducing the cogging torque, there is a technique of providing auxiliary grooves in the iron core of the stator. Such a technique is disclosed in Patent Document 1, Patent Document 2, and Patent Document 3.

JP 2001-25182 A JP 2006-230116 A International Publication No. WO2009 / 084151 Pamphlet

In the permanent magnet type rotating electrical machine of Patent Document 1, since the auxiliary grooves are provided in all the axial directions of the motor, there is a problem that the equivalent air gap length increases and the torque decreases. Moreover, although Patent Document 1, Patent Document 2 and Patent Document 3 are effective in reducing the pulsation number of the least common multiple of the number of poles and the number of slots and cogging torque that is an integral multiple thereof, there is an effect of permanent magnet sticking position error, shape error, There has been a problem that cogging torque components (components that pulsate the number of times corresponding to the number of slots in one rotation of the rotor) cannot be sufficiently suppressed due to variations on the rotor side such as variations in magnetic characteristics.
The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain a permanent magnet type rotating electric machine with reduced cogging torque and an electric power steering device using the same.

A permanent magnet type rotating electrical machine according to the present invention is provided with a rotor having a plurality of magnetic poles and a rotor core made of permanent magnets, a rotor armature, and a slot for housing the armature winding, and the rotor In the permanent magnet type rotating electrical machine, comprising: a stator including a stator core having a plurality of teeth facing each other, wherein an auxiliary groove is provided in a portion of the teeth facing the rotor of the teeth. In a section in a direction perpendicular to the rotation axis of the rotor having the permanent magnet and the rotor core, the protrusion having the permanent magnet and the magnetic core is provided on a part of the rotation axis direction of the iron core. Two or more regions having different magnetic circuit designs are provided in the direction of the rotation axis of the rotor due to a change in cross-sectional shape in the direction of the rotation axis, and the auxiliary groove is a part of the teeth of the stator core in the axial direction. Territory The regions where the auxiliary grooves are provided are a part of each region facing the region where the protrusions are provided and the region where the protrusions are not provided. It is.
The permanent magnet type rotating electrical machine of the present invention is provided with a rotor having a plurality of magnetic poles and a rotor iron core constituted by permanent magnets, a rotor armature, and a slot for housing the armature winding, and the rotating In a permanent magnet type rotating electrical machine, comprising a stator including a stator core having a plurality of teeth facing the child, wherein an auxiliary groove is provided in a portion of the teeth facing the rotor of the teeth, In the rotor, a plurality of magnetic poles are configured by embedding the permanent magnets in a plurality of holes in the rotation axis direction provided in the rotor core, and the magnetic poles adjacent to each other on the surface of the rotor core are formed. A recess groove is formed in a part of the axial direction along the magnetic pole, and a cross-sectional shape in a cross section perpendicular to the rotation axis of the rotor having the permanent magnet and the rotor core changes in the rotation axis direction. By Two or more regions having different air circuit designs are provided in the direction of the rotation axis of the rotor, the auxiliary groove is provided in a partial region in the axial direction of the teeth of the stator core, and the auxiliary groove is The provided area is a partial area for each area facing the area where the recessed groove is provided and the area where the recessed groove is not provided.

In the permanent magnet type rotating electrical machine according to the present invention, the cogging torque (the number of pulsations per one rotation of the rotor matches the number of slots) generated by variations on the rotor side such as a permanent magnet sticking position error, shape error, or variation in magnetic characteristics. Component).
Other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention with reference to the drawings.

It is sectional drawing which shows typically the permanent magnet type rotary electric machine in Embodiment 1 of this invention. It is A1-A2 sectional drawing of FIG. It is B1-B2 sectional drawing of FIG. It is C1-C2 sectional drawing of FIG. It is D1-D2 sectional drawing of FIG. FIG. 3 is a partial perspective view showing a stator core in the first embodiment. FIG. 3 is a perspective view showing a rotor in the first embodiment. 5 is a partial perspective view showing another stator core in the first embodiment. FIG.

FIG. 5 is a perspective view showing another rotor in the first embodiment. FIG. 8 is a partial cross-sectional view schematically showing a permanent magnet type rotating electric machine including the stator core of FIG. 6 and the rotor of FIG. 7. It is a fragmentary sectional view which shows typically a stator core and the permanent magnet type rotary electric machine which comprises the rotor of FIG. FIG. 10 is a partial cross-sectional view schematically showing a permanent magnet type rotating electric machine including the stator core of FIG. 8 and the rotor of FIG. 9. FIG. 10 is a partial cross-sectional view schematically showing a stator magnet core and a permanent magnet type rotating electric machine including the rotor of FIG. 9. It is sectional drawing which shows a rotor when the sticking position of a permanent magnet has shifted | deviated from the position of an ideal equal interval. It is explanatory drawing which shows the waveform of the cogging torque for rotation angle 30 degree | times (mechanical angle). It is explanatory drawing which shows the waveform of the cogging torque for rotation angle 30 degree | times (mechanical angle).

It is explanatory drawing which compares the cogging torque waveform of invention and a prior art example (without an auxiliary groove). It is explanatory drawing of the frequency analysis result of the cogging torque waveform of FIG. It is explanatory drawing which shows the histogram of the cogging torque of a prior art example. It is explanatory drawing which shows the histogram of the cogging torque of invention. It is explanatory drawing which shows the dimension of an auxiliary groove and a slot opening part. It is explanatory drawing which shows the relationship between the width | variety of an auxiliary groove, and a cogging torque. FIG. 6 is a cross-sectional view showing a permanent magnet type rotating electric machine in a second embodiment. FIG. 10 is a cross-sectional view showing another example of the permanent magnet type rotating electric machine in the second embodiment.

FIG. 12 is a cross-sectional view showing still another example of the permanent magnet type rotating electric machine in the second embodiment. FIG. 10 is a perspective view showing a rotor in a third embodiment. FIG. 9 is a partial perspective view showing a stator core in the third embodiment. FIG. 12 is a partial perspective view showing another example of the stator core in the third embodiment. FIG. 6 is a cross-sectional view showing a rotor in a third embodiment. FIG. 10 is a perspective view showing a rotor in a fourth embodiment. FIG. 10 is a partial perspective view showing a stator core in the fourth embodiment. FIG. 10 is a perspective view showing another example of a rotor in the fourth embodiment. FIG. 10 is a perspective view showing an electric power steering device in a fifth embodiment.

Embodiment 1 FIG.
1 is a schematic cross-sectional view on a plane that is parallel to and passes through a rotation axis of the permanent magnet type rotating electric machine according to Embodiment 1 of the present invention. A permanent magnet 1 is provided on the surface of the rotor core 2. Protrusions 8 are provided near the circumferential end of the permanent magnet 1, and the protrusions 8 are arranged so as to sandwich the permanent magnet 1. When the protrusion 8 is disposed between adjacent permanent magnets 1, the protrusion 8 and the permanent magnet 1 are simultaneously drawn in a cross-sectional view on a plane parallel to the rotation shaft (shaft) 10 and passing through the rotation shaft 10. Nonetheless, FIG. 1 is drawn at the same time to aid understanding.

  A rotary shaft 10 is press-fitted into the rotor core 2, and the rotor 30 is rotatable by bearings 11a and 11b. The rotor 30 is provided with a rotation angle sensor 14 that detects a rotation angle. The rotation angle sensor 14 includes, for example, a resolver, a hall sensor, a magnet, or an encoder. The stator core 3 is provided so as to face the permanent magnet 1, and the stator core 3 may be configured by, for example, laminating electromagnetic steel plates, or may be configured by a dust core. An armature winding 4 is wound around the stator core 3. The stator 40 is fixed to the frame 13 by press-fitting or shrink fitting, and the frame 13 is further fixed to the housing 12.

  An auxiliary groove 5 is provided in a portion of the stator core 3 facing the permanent magnet 1. Further, the auxiliary groove 5 is provided in a part in the rotation axis direction. In the example of FIG. 1, the auxiliary grooves 5 are arranged at three locations in the axial direction. Although details will be described later, the positional relationship in the axial direction in which the auxiliary grooves 5 are provided is set according to the protrusions 8.

  2, 3, 4, and 5 are cross-sectional views in a plane perpendicular to the rotating shaft 10 of FIG. 1. 2, 3, 4 and 5 are cross sections taken along lines A1-A2, B1-B2, C1-C2, and D1-D2 in FIG. 1, respectively. In these sectional views, the permanent magnet 1 is affixed to the surface of the rotor core 2, and the number of poles (number of magnetic poles) is 10 in this example. Furthermore, the cross-sectional shape of the permanent magnet 1 is a semi-cylindrical shape, and the torque pulsation is reduced by reducing the harmonic component of the magnetic flux and making the induced voltage sinusoidal. The rotor core 2 is provided with a protruding portion 8 made of the same material by a part of the rotor core 2, and serves to fix and hold the permanent magnet 1 so as not to slide in the circumferential direction.

  On the other hand, the stator core 3 of the stator 40 is provided with a slot 6 for winding the armature winding 4. In the example of FIG. 2, the armature winding 4 is intensively wound around the teeth 7 extending in the radial direction of the stator core 3, and the number of slots is twelve. Armature windings are wound around all twelve teeth. Furthermore, the number of phases of the permanent magnet type rotating electrical machine is 3, and when these are U phase, V phase, and W phase, the winding arrangement is U1 +, U1−, V1−, V1 +, W1 + as shown in FIG. , W1−, U2−, U2 +, V2 +, V2−, W2−, W2 +. Here, + and-indicate winding directions, and + and-indicate that the winding directions are opposite to each other. Furthermore, U1 + and U1− are connected in series, and U2− and U2 + are also connected in series. These two series circuits may be connected in parallel or may be connected in series. The same applies to the V and W phases. Further, the three phases may be Y-connected or delta-connected.

  FIG. 2 is a cross section taken along line A1-A2 of FIG. 1. In the cross section, the stator core 3 is not provided with an auxiliary groove, and the rotor core 2 is provided with a protrusion 8. FIG. 3 is a B1-B2 cross section of FIG. 1, in which an auxiliary groove 5 is provided in the stator core 3, and a protrusion 8 is provided in the rotor core 2. 4 is a cross section taken along line C1-C2 of FIG. 1, in which the auxiliary core 5 is not provided in the stator core 3, and the protrusion 8 is not provided in the rotor core 2. FIG. FIG. 5 is a D1-D2 cross section of FIG. 1, in which the auxiliary groove 5 is provided in the stator core 3, and the protrusion 8 is not provided in the rotor core 2.

  6 is a partial perspective view showing a stator core of the permanent magnet type rotating electric machine of FIG. FIG. 6 shows only six half of the twelve teeth to help understand the present invention. The stator core 3 has a tooth 7 extending in the radial direction and facing the permanent magnet, and an auxiliary groove 5 is provided on a surface facing the rotor at the tip of the tooth 7. The auxiliary grooves 5 are arranged at three locations in the axial direction, and the auxiliary grooves 5 near the center in the axial direction have a longer axial length than the other two auxiliary grooves 5.

  FIG. 7 is a perspective view showing a rotor of the permanent magnet type rotating electric machine of FIG. For simplicity, the portion where the rotating shaft 10 protrudes from the end face of the rotor core 2 is omitted. Further, the protective cover of the permanent magnet 1 is omitted. The permanent magnet 1 is provided on the surface of the rotor core 2, and a protrusion 8 is provided between adjacent permanent magnets 1. Furthermore, the protrusion part 8 is provided in the both ends of the axial direction. When the protrusion 8 is made of a magnetic material, the configuration of the magnetic circuit in the plane cross section perpendicular to the rotation shaft 10 is different between the cross section of the portion with the protrusion 8 and the cross section of the portion without the protrusion 8. It will be.

  The presence of the protrusions 8 has the effect of preventing the permanent magnet 1 from shifting in the circumferential direction and the effect of facilitating positioning of the permanent magnet 1, but the presence or absence of the protrusions 8 changes in the axial direction, When the magnitude of 8 changes in the axial direction, there is a problem that the cogging torque increases because the magnetic circuit is not uniform in the axial direction. In particular, the cogging torque due to variations in the position, shape or characteristics of the permanent magnet 1 may increase. In the present invention, in the permanent magnet type rotating electrical machine having the rotor 30 having the configuration of at least two kinds of magnetic circuits as described above, an object of the present invention is to provide an arrangement of the auxiliary grooves 5 that can effectively reduce the cogging torque. Yes.

  Hereinafter, the arrangement of the auxiliary grooves 5 for the purpose of reducing the cogging torque will be described in detail. FIG. 10 is a cross-sectional view of the permanent magnet type rotating electric machine of FIG. 1, that is, the permanent magnet type rotating electric machine having the stator core of FIG. 6 and the rotor of FIG. Indicate. In FIG. 10, symbols A and B are used to distinguish the configuration of the magnetic circuit on the rotor 30 side. A region having the protrusion 8 is indicated by A, and a region having no protrusion is indicated by B. In this example, since the protrusions 8 are provided at both ends in the axial direction, the regions A, B, and A are arranged in this order from the top in FIG. Further, the lengths of these regions in the axial direction are indicated by Lr1, Lr2, and Lr3. On the other hand, on the side of the stator 40, an area without the auxiliary groove 5 is indicated by X and an area with the auxiliary groove 5 is indicated by Y. In FIG. 10, X, Y, X, Y, X, Y, and X are arranged in this order from the top toward the paper surface. Furthermore, the lengths in the axial direction of these regions are indicated by Ls1, Ls2, Ls3, Ls4, Ls5, Ls6, and Ls7.

  The broken line in FIG. 10 is a line indicating a plane perpendicular to the axis, and is the same for FIGS. 11, 12, and 13. The broken lines in FIG. 10 indicate that the positions of the end face in the axial direction of the protrusion 8 and the end face in the axial direction of the auxiliary groove 5 are the same. For example, it is shown that the lower end surface of the upper protrusion 8 toward the paper surface coincides with the lower end surface of the upper auxiliary groove 5 toward the paper surface. 10, 11, 12, and 13, the same position in the axial direction on the stator side corresponding to the axial position on the rotor side is shown at the position of the broken line. In FIG. 10, the relational expression Lr1 = Ls1 + Ls2 holds. Similarly, the relational expressions Lr2 = Ls3 + Ls4 + Ls5 and Lr3 = Ls6 + Ls7 hold.

  Next, a mechanism that can significantly reduce the cogging torque when the auxiliary grooves 5 are arranged as shown in FIG. 10 will be described. The ten permanent magnets 1 in the rotors of FIGS. 2 to 5 and FIG. 7 have the same sticking positions and the same sectional shape. However, in practice, manufacturing variations occur. For example, even if it is applied with high accuracy, the application positions of the permanent magnets 1 are not evenly spaced and may deviate by several μm to 100 μm in the circumferential direction. On the other hand, it is assumed that the cross-sectional shape is not an ideal left-right symmetric shape, and the thickness of one of the left and right increases and the other thickness decreases. An example is shown in FIG.

  In FIG. 14, it has shown that the sticking position of a permanent magnet has shifted | deviated to the direction shown by the arrow from the position of an ideal equal interval. Furthermore, the cross-sectional shape is not left-right symmetric, and the kamaboko-shaped apex portion moves in the direction of the arrow, indicating that it is not left-right symmetric. As described above, when variation occurs in the rotor, the cogging torque increases, and a component that pulsates as many times as the number of slots per one rotation of the rotor appears. In the example of the first embodiment, since the number of slots is 12, a cogging torque having a period of 360 degrees / 12 = 30 degrees in terms of mechanical angle appears 12 times in one rotation of the rotor.

  FIGS. 15 and 16 are diagrams showing waveforms of cogging torque corresponding to a rotation angle of 30 degrees (mechanical angle). The waveform indicated by A-X in FIG. 15 shows that when the stator 40 and the rotor 30 of the permanent magnet type rotating electric machine are uniformly “with protrusions and without auxiliary grooves”, the variation of the permanent magnet 1 is as shown in FIG. The cogging torque waveform when the state is reached is shown. On the other hand, the waveform indicated by A-Y shows the cogging torque when the variation of the permanent magnet 1 is in the state shown in FIG. 14 when the stator 40 and the rotor 30 are uniformly “with protrusions and with auxiliary grooves”. The waveform is shown. These waveforms show that a component with a mechanical angle of 30 degrees is large and the cogging torque is large.

  Furthermore, the waveform shown in the legend “invention” in FIG. 15 indicates that the variation of the permanent magnet 1 is the state shown in FIG. 14 when “with protrusions and without auxiliary grooves” and “with protrusions and with auxiliary grooves” are provided simultaneously. This is a waveform of the cogging torque at the time, and is an average waveform of the two waveforms. In this waveform, the component with a mechanical angle of 30 degrees is very small, and the cogging torque can be greatly reduced. By providing the auxiliary groove 5, the phase of the component having a mechanical angle of 30 degrees is reversed to cancel out the cogging torque in the portion without the auxiliary groove 5, thereby greatly reducing the cogging torque.

  Similarly, FIG. 16 shows the variation of the permanent magnet 1 when the waveform indicated by BX is “no protrusion and no auxiliary groove” and the waveform indicated by BY is “no protrusion and an auxiliary groove”. 14 shows a cogging torque waveform when 14 state is reached. On the other hand, when the waveform of the invention is provided with “no protrusion and no auxiliary groove” and “no protrusion and with an auxiliary groove” at the same time, the cogging torque of the permanent magnet 1 when the variation becomes the state of FIG. The waveform is an average waveform of the two waveforms. Also in this case, it can be seen that the component of the mechanical angle of 30 degrees is very small, and the cogging torque can be greatly reduced.

  Further, the waveform of AX in FIG. 15 and the waveform of BX in FIG. 16 are different, and the waveform of AY in FIG. 15 and the waveform of BY in FIG. 16 are different. You need to be careful. This indicates that the cogging torque cannot be canceled sufficiently with the AX waveform and the BY waveform, and that the cogging torque cannot be canceled with the BX waveform and the AY waveform. Accordingly, in order to sufficiently reduce the component having a mechanical angle of 30 degrees, it is necessary to consider the arrangement of the protrusions 8, that is, the magnetic circuit design on the rotor 30 side, in the arrangement of the auxiliary grooves 5. Therefore, if the auxiliary grooves as shown in FIG. 10 are arranged, the AX waveform and the AY waveform can be offset in the axial length Lr1 region and the Lr3 region, and the axial length Lr2. In this region, the BX waveform and the BY waveform can be offset, so that the cogging torque can be greatly reduced. The axial length in which the auxiliary groove 5 is provided is about 1/2 (for example, 1/2 ± 10%), more preferably 1/2 (for example, 1/2 ± 5%) of the axial length of the stator core. It is good to do.

Furthermore, in FIG. 10, Ls1 = Ls2 = Lr1 / 2
Ls4 = Ls3 + Ls5 = Lr2 / 2
Ls6 = Ls7 = Lr3 / 2
Then, the axial lengths of the AX region and the AY region are equal, and the axial lengths of the BX region and the BY region are equal. It becomes the structure which can demonstrate more.

  FIG. 17 shows a comparison between the configuration of FIG. 10 and the cogging torque waveform when the auxiliary groove 5 is not provided as a conventional example. The conventional cogging torque is standardized with a maximum value of 100%. A broken line is a conventional cogging torque waveform, and a component that pulsates 12 times with one rotation of the rotor is noticeable. On the other hand, it can be confirmed that the invention of the solid line is the cogging torque waveform of the configuration of FIG. FIG. 18 shows a frequency analysis result of the cogging torque waveform of FIG. In the invention, the cogging torque twelfth order component caused by the variation on the rotor 30 side can be greatly reduced as compared with the conventional example.

  The above is the case where the variation pattern is shown in FIG. 14, but in order to demonstrate the effect of the invention, it is assumed that random variations occur in each of the ten permanent magnets. A histogram was created for the twelfth order component (component whose pulsation number matches the slot number). The results are shown in FIGS. FIG. 19 is a histogram of a conventional example, and FIG. 20 is a histogram of the configuration (invention) of FIG. The vertical axis represents the frequency, and the horizontal axis represents the magnitude of the cogging torque. Comparison is made assuming that the variation condition on the rotor 30 side is the same. In FIG. 19, the cogging torque is widely distributed, and there is a problem that the cogging torque becomes large depending on the variation pattern.

  However, in the configuration of the invention, it can be seen that the cogging torque is small regardless of the variation pattern of the permanent magnet 1 of the rotor 30. That is, it is possible to obtain a permanent magnet type rotating electrical machine having high robustness against manufacturing variations on the rotor 30 side. In the configuration of the conventional auxiliary groove, a reduction effect is aimed at a component in which the number of pulsations per rotation of the rotor coincides with the least common multiple of the number of poles and the number of slots, and a component generated due to variations on the rotor 30 side ( A sufficient reduction effect cannot be obtained for a component whose pulsation number matches the slot number.

  11 can obtain the same effect as that of FIG. FIG. 11 is an example in which the arrangement of the protrusions 8 of the rotor core 2 is the same as that of FIG. 10, but the arrangement of the auxiliary grooves 5 of the stator core 3 is different. In this example, the auxiliary grooves 5 in the area of Ls4 in FIG. 10 are provided in the areas of Ls3 and Ls5, and the auxiliary grooves 5 are arranged in two axial directions. Even in such an arrangement of the auxiliary grooves 5, the cogging torque reduction effect can be obtained by the mechanism described in the example of FIG. Similarly to FIG. 10, the axial length in which the auxiliary groove 5 is provided is about ½ (for example, ½ ± 10%) of the axial length of the stator core, and more preferably ½ (for example, 1/2 ± 5%) is preferable.

Furthermore, in FIG. 11, Ls1 = Ls2 = Lr1 / 2
Ls4 = Ls3 + Ls5 = Lr2 / 2
Ls6 = Ls7 = Lr3 / 2
Then, the axial lengths of the AX region and the AY region are equal, and the axial lengths of the BX region and the BY region are equal. Needless to say, the configuration is such that the above can be further demonstrated.

  In FIGS. 6, 7, 10, and 11, the example in which the protrusions 8 are disposed at both ends in the axial direction has been described, but the scope of application of the present invention is not limited to this. Another example is shown in FIGS. FIG. 8 is a partial perspective view showing another stator core of the permanent magnet type rotating electric machine according to the first embodiment. FIG. 8 shows six teeth, half of the twelve, to help understanding. FIG. 9 is a perspective view showing another rotor of the permanent magnet type rotating electric machine according to the first embodiment. For simplicity, the portion where the rotating shaft 10 protrudes from the end face of the rotor core 2 is omitted. Further, the protective cover of the permanent magnet 1 is omitted. The permanent magnet 1 is provided on the surface of the rotor core 2. A protrusion 8 made of the same material is provided at a part of the rotor core 2 between the adjacent permanent magnets 1 to fix and hold the permanent magnet 1. Further, the protrusion 8 is provided at a position separated from the both ends in the axial direction by a predetermined distance.

  12 and 13 are cross-sectional views corresponding to this example. 12 and 13, two protrusions 8 of the rotor core are provided in the axial direction, and the positions in the axial direction are separated from the end portions by Lr1 and Lr5. FIG. 12 shows an example in which three auxiliary grooves 5 of the stator core 3 are arranged in the axial direction, and FIG. 13 shows an example in which two auxiliary grooves 5 are arranged in two places. If the auxiliary grooves 5 are arranged as shown in FIG. 12, the AX waveform and the AY waveform can be offset in the axial length Lr2 region and the Lr4 region, and the axial lengths Lr1, Lr3. , Lr5, the BX waveform and the BY waveform can be canceled out, so that the cogging torque can be greatly reduced. The axial length in which the auxiliary groove 5 is provided is about 1/2 (for example, 1/2 ± 10%), more preferably 1/2 (for example, 1/2 ± 5%) of the axial length of the stator core. It is good to do.

Furthermore, in FIG. 12, Ls1 = Ls2 = Lr1 / 2
Ls3 = Ls4 = Lr2 / 2
Ls5 + Ls7 = Ls6 = Lr3 / 2
Ls8 = Ls9 = Lr4 / 2
Ls10 = Ls11 = Lr5 / 2
Then, the axial lengths of the AX region and the AY region are equal, and the axial lengths of the BX region and the BY region are equal. It becomes the structure which can demonstrate more.

  On the other hand, when the auxiliary grooves 5 are arranged as shown in FIG. 13, the AX waveform and the AY waveform can be canceled out in the axial length Lr2 region and the Lr4 region, and the axial length In the regions Lr1, Lr3, and Lr5, the BX waveform and the BY waveform can be canceled out, so that the cogging torque can be greatly reduced. The axial length in which the auxiliary groove 5 is provided is about 1/2 (for example, 1/2 ± 10%), more preferably 1/2 (for example, 1/2 ± 5%) of the axial length of the stator core. It is good to do.

Furthermore, in FIG. 13, Ls1 = Lr1
Ls2 = Ls3 = Lr2 / 2
Ls7 = Ls8 = Lr4 / 2
Ls4 + Ls6 = Ls1 + Ls5 + Ls9 = (Lr1 + Lr3 + Lr5) / 2
Ls9 = Lr5
Then, the axial lengths of the AX region and the AY region are equal, and the axial lengths of the BX region and the BY region are equal. It becomes the structure which can demonstrate more.

  In the example shown this time, the presence or absence of the protrusion of the rotor core changes in the axial direction, but the present invention is not limited to this. If there are two or more regions in the axial direction where the magnetic circuit design of the rotor is different, such as when there is a recess instead of a protrusion between adjacent permanent magnets, or when the cross-sectional shape of the permanent magnet changes, the same The cogging torque can be greatly reduced by providing the auxiliary groove by the method.

  From the above, in the rotor, at least one of the cross-sectional shape in the cross section perpendicular to the rotation axis of the rotor core and the cross-sectional shape in the cross section perpendicular to the rotation axis of the permanent magnet changes in the direction of the rotation axis. Have two or more regions in the axial direction, the auxiliary groove is provided in a partial region of the stator core in the axial direction, and the region provided with the auxiliary groove is a magnetic circuit of the rotor If the design is configured to be a partial region for each region facing the same region, cogging torque (due to variations in the rotor side such as a permanent magnet sticking position error, shape error, or magnetic property variation) The component in which the number of pulsations in one rotation of the rotor matches the number of slots) can be greatly reduced. Note that the above-mentioned region facing the same region of the rotor magnetic circuit design is the same region where the rotor magnetic circuit design when the rotor side and the stator side are separated by a plane perpendicular to the axis. The corresponding stator side area is shown.

  In addition, the region where the auxiliary groove is provided is generated in the region where the auxiliary groove is provided if the magnetic circuit design of the rotor is configured to be half the axial length of each region facing the same region. The effect of offsetting the cogging torque to be generated and the cogging torque generated in the region where the auxiliary groove is not provided is sufficiently exerted, and therefore, due to variations on the rotor side such as a permanent magnet sticking position error, shape error, or magnetic characteristic variation The generated cogging torque (a component in which the number of pulsations in one rotation of the rotor matches the number of slots) can be reduced more effectively.

  If a configuration in which a projection is provided in a part of the rotor core in the axial direction is provided, there is an effect that the positioning of the permanent magnet can be performed because the projection is provided, so that the accuracy of the sticking position is improved. . At the same time, an auxiliary groove is provided to prevent an increase in cogging torque due to a difference in magnetic circuit design caused by the protrusion, and a cogging torque generated by variations on the rotor side (the number of pulsations in one rotation of the rotor is a slot). (Components matching the number) can be more effectively reduced. In addition, as shown in FIGS. 6 and 8, the auxiliary groove is not provided at the axial end, so that the auxiliary groove is rotated at the axial end compared to the case where the auxiliary groove is provided at the axial end. The part where the gap with the child is large is reduced. This increases the effect of preventing foreign matter from entering the gap portion between the stator and the rotor.

  Next, the shape of the auxiliary groove will be described. FIG. 21 is a diagram illustrating the auxiliary groove width Wd, auxiliary groove depth Hd, slot opening width Ws, and tooth tip thickness Hs. In the structure of the present invention, the auxiliary groove is obtained by inverting the phase of the component in which the number of pulsations of the cogging torque matches the number of slots in the portion provided with the auxiliary groove and the portion not provided with the auxiliary groove. The selection of the shape affects the magnitude of the effect. FIG. 22 is a graph in which the ratio of the width Wd of the auxiliary groove to the slot opening width Ws is plotted on the horizontal axis, and the overall value of cogging torque when variation occurs in the rotor is plotted on the vertical axis.

  When Wd / Ws = 0, that is, when the auxiliary groove is not provided, if Wd / Ws ≧ 1.0, the cogging torque is ½ or less that when the auxiliary groove is not provided. Further, when Wd / Ws ≧ 1.25, the cogging torque is as small as 0.001 Nm. If the cogging torque due to rotor variations is suppressed to this level, for example, when a rotating electric machine is incorporated in an electric power steering device described later, the driver does not feel the cogging torque and a good steering feeling is achieved. The effect that it can be obtained is acquired.

When Wd / Ws ≧ 1.0, the pulsation component of the permeance due to the stator core slot can be changed to reverse the phase of the component whose cogging torque pulsation number matches the slot number. Can cancel each other with cogging torque. When one auxiliary groove is provided, Wd / Ws ≧ 1.0 may be satisfied. When two or more auxiliary grooves are provided, the total width of all auxiliary grooves provided in the teeth is defined as Wd / Wd / The same effect can be obtained if Ws ≧ 1.0.
Further, the depth Hd of the auxiliary groove is desirably larger than the thickness Hs of the tooth tip. This also changes the pulsation component of the permeance due to the slots of the stator core, and can reverse the phase of the cogging torque component whose pulsation number matches the slot number. The above-described canceling effect with the cogging torque in the portion without the auxiliary groove can be sufficiently exhibited.

  In Patent Document 1, Patent Document 2, and Patent Document 3, an example in which two or more auxiliary grooves are provided in the circumferential direction in each tooth is described, but in Embodiment 1, the auxiliary groove is in the circumferential direction of each tooth. One in the center. The cogging torque S-order component (S is the number of slots) generated due to variations on the rotor side is largely related to the S-order component of the permeance pulsation due to the slots of the stator, but by providing one auxiliary groove, There is an effect that it is easy to change the amplitude and phase of the S-order component of the permeance pulsation. The smaller the number of auxiliary grooves, the smaller the average gap length. Therefore, there is only one auxiliary groove at the center in the circumferential direction and only a part in the axial direction. Limit to the limit.

  In the first embodiment, the auxiliary groove has a shape in which the iron core is cut out in a quadrangular shape, but is not limited thereto. For example, it goes without saying that the same effect can be obtained with a shape in which the iron core is cut out in an arc shape, a shape cut out in a triangular shape, or the like. In addition, the permanent magnet type rotating electrical machine having 10 poles and 12 slots shown in the first embodiment has a winding factor of the fundamental wave larger than that of the conventional pole number: slot number = 2: 3. Suitable for small and high power applications. The pole number and the least common multiple of the number of slots are 60 for the 10 poles and 12 slots and 24 for the 8 poles and 12 slots, and the cogging torque of the order of the least common multiple is 10 poles and 12 slots. small. However, there is a problem that the cogging torque due to the variation on the rotor side is larger than the 8-pole 12-slot and the robustness against the manufacturing variation is low. However, since the problem can be solved by the first embodiment, it is possible to obtain a permanent magnet type rotating electric machine that achieves both a small and high output and a reduction in cogging torque due to manufacturing variations.

  The example which provided the projection part in the rotor iron core was shown. While there is an effect to prevent the positioning of the permanent magnet and displacement in the circumferential direction if there is a protrusion, there is a problem that the cogging torque S-order component (S is the number of slots) is increased due to different magnetic circuit design. The first embodiment can solve this problem, and it is possible to achieve both the effect of preventing the positioning of the permanent magnet and the shift in the circumferential direction and the reduction of the cogging torque S-order component.

Embodiment 2. FIG.
In the first embodiment, the example of the number of poles (number of magnetic poles) 10 and the number of slots 12 is described, but the present invention is not limited to this. If the number of poles of the permanent magnet type rotating electrical machine is P and the number of slots is S,
0.75 <S / P <1.5
In the case of the combination having the relationship, the winding coefficient is higher than in the case of S / P = 0.75 and S / P = 1.5 described in Patent Document 1, Patent Document 2, and Patent Document 3. It is known that a permanent magnet type rotating electrical machine having a small size and high torque can be obtained by efficiently using the magnetic flux of the permanent magnet.

  Furthermore, since the least common multiple of the number of poles and the number of slots is large, the cogging torque component that pulsates the number of times corresponding to the least common multiple of the number of poles and the number of slots in one rotation of the rotor is S / P = 0.75, S / P It is also known that it is smaller than the case of = 1.5. On the other hand, the cogging torque S-order component (component that pulsates S times by one rotation of the rotor) generated by variations on the rotor side, such as a permanent magnet sticking position error, shape error, or magnetic characteristic variation, is large. The problem is that the robustness against variations is low. Therefore, it is necessary to solve this problem in a permanent magnet type rotating electrical machine that is mass-produced as in an electric power steering apparatus.

Therefore, the present invention is 0.75 <S / P <1.5.
When applied to a combination of permanent magnet type rotating electrical machines having such a relationship, the robustness is high with respect to variations on the rotor side, and the cogging torque S-order component can be reduced.
0.75 <S / P <1.5
FIG. 23 shows an example of P = 14, S = 12, FIG. 24 shows an example of P = 8, S = 9, and FIG. 25 shows P = 10, S = 9. Indicated.

  One auxiliary groove 5 is provided for each tooth. 23, 24, and 25 are cross-sectional views, but are cross-sectional views of a portion where the auxiliary groove 5 is provided, and there are portions where the auxiliary groove 5 is not provided depending on the position in the axial direction as in the first embodiment. The figure is omitted. With such a configuration, since the winding coefficient is high, it is possible to achieve both the effect of being small and having high torque and the effect of increasing robustness against variations on the rotor side.

In addition, since the same effect can be obtained by a combination of the number of poles and an integral multiple of the number of slots, generalization including the number of poles P = 10 and the number of slots S = 12,
Let n be a natural number,
Number of poles P = 12n ± 2n, number of slots S = 12n
Number of poles P = 9n ± n, number of slots S = 9n
If so, the same effect can be obtained.

Embodiment 3 FIG.
In the above embodiments, the permanent magnet is an example of the surface magnet type provided on the surface of the rotor core, but the present invention is not limited to this and can be applied. FIG. 26 shows a magnet-embedded structure in which the permanent magnet 1 is embedded in a plurality of holes 9 (FIG. 29) provided in the rotor core 2 in the rotation axis direction. A rotating shaft 10 is inserted into the rotor core 2. A flat iron plate 1 is embedded in the rotor core 2 to form a plurality of magnetic poles. Further, the rotor core 2 is provided with a recessed groove 2a in a part in the axial direction along the magnetic pole between adjacent magnetic poles on the surface portion. FIG. 29 shows a cross-sectional view of the portion having the recessed groove 2a. The permanent magnet 1 is embedded in the hole 9 of the rotor core 2, and nonmagnetic gaps 9 a are provided on the left and right sides of the permanent magnet 1. Furthermore, an iron core portion 2b between the magnetic poles is provided in the magnetic path portion of the rotor iron core 2 provided between the adjacent permanent magnets 1.

  The cross-sectional shape of the rotor core 2 in the cross section perpendicular to the rotation axis 10 changes in the axial direction as can be seen from FIG. The region indicated by A is provided with a recessed groove 2a, and the region indicated by B has a shape having no recessed groove. The cross-sectional shape changes in the order of ABAB in the axial direction, and regions with different magnetic circuit designs are arranged. Furthermore, the axial lengths of these regions are Lr1, Lr2, Lr3, and Lr4. By making the magnetic circuit design different in the axial direction in this way, the cogging torque of the order corresponding to the least common multiple of the number of poles and the number of slots and the number of poles and slots can be reduced by using the canceling effect. Can do. In FIG. 26, the cogging torque and torque ripple in the region A and the cogging torque and torque ripple in the region B can be canceled.

  However, the cogging torque due to variations on the rotor side, such as a position error, shape error, or variation in magnetic characteristics of the permanent magnet, may increase on the contrary. However, this problem can be solved by adopting the stator core structure described below.

  27 and 28 are partial perspective views showing only one tooth of the stator core for the sake of easy understanding. Although the first embodiment has been described with reference to cross-sectional views as illustrated in FIGS. 10 to 14, here, description will be made using perspective views. The permanent magnet type rotating electrical machine of the third embodiment is a configuration example of 10 poles and 12 slots in which 12 stator cores 3 of FIG. 27 are arranged in the circumferential direction so as to surround the rotor of FIG. It is. Further, the positional relationship between the rotor 30 and the stator core 3 is a positional relationship in which the axial end portions substantially coincide or coincide with each other.

  In the stator core 3 of FIG. 27, in the region facing the region A where the recessed groove 2 a of the rotor core 2 is provided, the stator core 3 has a region X without the auxiliary groove 5 and a region with the auxiliary groove 5. Y is composed of two types of areas. The region facing the region B without the concave groove 2a is also composed of two types of regions, a region X without the auxiliary groove 5 and a region Y with the auxiliary groove 5. With such a configuration, as described in the first embodiment, it is possible to significantly reduce the cogging torque by utilizing the canceling effect. The axial length in which the auxiliary groove 5 is provided is about ½ (for example, ½ ± 10%), more preferably ½ (for example, ½ ± 5%) of the axial length of the stator core. ).

Furthermore, in FIGS.
Ls1 = Ls2 = Lr1 / 2
Ls3 = Ls4 = Lr2 / 2
Ls5 = Ls6 = Ls3 / 2
Ls7 = Ls8 = Lr4 / 2
Then, as described in the first embodiment, the axial lengths of the AX region and the AY region are equal, and the axial lengths of the BX region and the BY region are the same. Therefore, the cogging torque reduction effect can be further exhibited.

  Also in the stator core 3 of FIG. 28, the stator core 3 is divided into two types, a region X without the auxiliary groove 5 and a region Y with the auxiliary groove 5 in the region facing the region A where the recessed groove 2 a is provided. The region that is composed of the region and faces the region B without the concave groove 2 a is also composed of two types of regions, a region X without the auxiliary groove 5 and a region Y with the auxiliary groove 5. The axial length in which the auxiliary groove 5 is provided is about ½ (for example, ½ ± 10%) of the axial length of the stator core 3, and more preferably ½ (for example, ½ ± 5). %).

Further, in FIGS.
Ls1 = Ls2 / 2 = Lr1 / 2
Ls2 / 2 = Ls3 / 2 = Lr2 / 2
Ls3 / 2 = Ls4 / 2 = Lr3 / 2
Ls4 / 2 = Ls5 = Lr4 / 2
As a result, the axial lengths of the AX and AY regions are equal, and the axial lengths of the BX and BY regions are equal. It becomes the structure which can be exhibited more.

  With such a configuration, the cogging torque does not increase significantly even if the position of the permanent magnet shifts or the characteristics vary in the hole provided in the rotor core. That is, it is highly robust against variations on the rotor side, and the cogging torque S-order component can be reduced (S is the number of slots in the stator core). Furthermore, when the shape of the hole 9 of the rotor core is designed to be large in the left-right direction of the permanent magnet, and the gap 9a is formed on the left and right of the permanent magnet when the permanent magnet is inserted, the adjacent permanent magnet Since the magnetic path portion of the rotor core provided between them, that is, the core portion 2b between the magnetic poles can be made thin, the leakage magnetic flux can be reduced, and a small high torque rotating electrical machine can be obtained.

  However, since there are gaps on the left and right sides of the permanent magnet, there is a problem in that the position of the permanent magnet is shifted and the S-order component of the cogging torque is increased. However, with the configuration provided with the stator core of the present invention, there is an effect that the robustness is high with respect to variations on the rotor side and the cogging torque S-order component can be reduced. Furthermore, by adopting a structure in which the magnetic circuit design is different in the axial direction, it is possible to reduce the cogging torque of the order that matches the torque ripple of the sixth electrical angle and the least common multiple of the number of poles and the number of slots.

Embodiment 4 FIG.
In the first to third embodiments, at least one of the cross-sectional shape in the cross section perpendicular to the rotation axis of the rotor core and the cross-sectional shape in the cross section perpendicular to the rotation axis of the permanent magnet changes in the direction of the rotation axis. Although the permanent magnet type rotating electrical machine having two or more regions having different designs in the rotation axis direction has been described, another configuration example will be described here. FIG. 30 is a perspective view of a rotor having the permanent magnet 1 provided on the surface portion of the rotor core 2 and having 10 poles. Two permanent magnets 1 are arranged in the axial direction and further provided with a stepped skew.

  As described above, in the rotor 30 configured by arranging two or more permanent magnets 1 in the axial direction, the variation in the shape of the permanent magnet shown in FIG. There may be a large change between the above permanent magnets 1. In this case, there is a problem that the effect of canceling out cannot be obtained unless the auxiliary grooves of the stator core are properly provided, and the cogging torque is increased. Therefore, in the present invention, the problem is solved by the following configuration.

  As shown in FIG. 30, M1 and M2 are made to correspond to the permanent magnets 1 arranged in the direction of the rotation axis in the direction of the rotation axis. Further, the lengths of these regions in the axial direction are Lr1 and Lr2. On the other hand, FIG. 31 is a partial perspective view showing only one tooth out of twelve stator cores. The region where the auxiliary groove 5 is not provided is X, the region where the auxiliary groove 5 is provided is Y, and the regions are arranged in the order of XYXY. Each axial length is Ls1, Ls2, Ls3, Ls4.

  Since the cogging torque increases when the variation in the shape of the permanent magnet and the variation in the pasting position and the like are different between M1 and M2, both the presence and absence of the auxiliary groove 5 are provided in each of the regions M1 and M2. The structure. With such a structure, the canceling effect of M1-X and M1-Y and the canceling effect of M2-X and M2-Y are sufficiently exhibited, and the permanent magnets are arranged between the permanent magnets arranged in the rotation axis direction. The cogging torque S-order component can be reduced even when the variation in shape, the error in the pasting position, or the variation in magnetic characteristics changes greatly between two or more permanent magnets arranged in the axial direction (S is the stator). Number of slots in the iron core). The axial length in which the auxiliary groove is provided is about ½ (for example, ½ ± 10%), more preferably ½ (for example, ½ ± 5%) of the axial length of the stator core. It is good.

Further, in FIGS.
Ls1 = Ls2 = Lr1 / 2
Ls3 = Ls4 = Lr2 / 2
Then, the axial lengths of the M1-X region and the M1-Y region are equal, and the axial lengths of the M2-X region and the M2-Y region are equal. It becomes the structure which can be exhibited more.

  In FIG. 30, the permanent magnet 1 is an example of a segment magnet, but the present invention is not limited to this. FIG. 32 shows an example in which two ring-shaped magnets are arranged in the axial direction. Ring-shaped permanent magnets include those with radial anisotropy, polar anisotropy, and no anisotropy, but the S-order component of cogging torque (S is the stator core due to variations in orientation and magnetization) Number of slots) may occur. As in the example of FIG. 30, when the state of variation is different between the permanent magnets arranged in the axial direction, the effect of offsetting is not obtained unless the auxiliary grooves of the stator core are properly provided, and the cogging torque There is a problem that increases. Therefore, if an auxiliary groove is arranged as in the stator iron core of FIG. 31, a configuration that can more effectively reduce the cogging torque is obtained. In the fourth embodiment, an example in which two are arranged in the axial direction is shown, but it goes without saying that the same effect can be obtained even in the case of three or more. Further, for example, in the structure other than the configuration of FIG. 31, for example, a region in which the auxiliary groove is not provided is X, a region in which the auxiliary groove is provided is Y, and the same arrangement is obtained in the order of XYYX.

30 and FIG. 31, the example of the number of poles (number of magnetic poles) 10 and the number of slots 12 has been described. However, the fourth embodiment is not limited thereto. If the number of poles of the permanent magnet type rotating electrical machine is P and the number of slots is S,
0.75 <S / P <1.5
In the case of the combination having the relationship, the winding coefficient is higher than in the case of S / P = 0.75 and S / P = 1.5 described in Patent Document 1, Patent Document 2, and Patent Document 3. It is known that a permanent magnet type rotating electrical machine having a small size and high torque can be obtained by efficiently using the magnetic flux of the permanent magnet.

Further, since the least common multiple of the number of poles and the number of slots is large, the cogging torque component that pulsates the number of times that matches the least common multiple of the number of poles and the number of slots in one rotation of the rotor is S / P = 0.75, S / P It is also known that it is smaller than the case of = 1.5. On the other hand, a cogging torque S-order component (a component that pulsates S times by one rotation of the rotor) generated by variations on the rotor side such as a permanent magnet sticking position error, shape error, or magnetic characteristic variation is large, and the rotor side The problem is that the robustness against variations is low. Therefore, it is necessary to solve this problem in a permanent magnet type rotating electrical machine that is mass-produced as in the case of being mounted on an electric power steering device. Therefore, the fourth embodiment is changed to 0.75 <S / P <1.5.
When applied to a combination of permanent magnet type rotating electrical machines having such a relationship, the robustness is high with respect to variations on the rotor side, and the cogging torque S-order component can be reduced.
Moreover, in FIG. 31, since the auxiliary groove is provided at one central portion in the circumferential direction of the teeth of the stator core, an effect that the torque is reduced less than the conventional example can be obtained. Therefore, it is possible to achieve both compact realization of high torque and high robustness, and to obtain a special effect that cannot be obtained in Patent Document 1, Patent Document 2, and Patent Document 3 by the configuration of the fourth embodiment. Can do.

Embodiment 5. FIG.
FIG. 33 is a conceptual diagram showing an electric power steering device for a vehicle using the permanent magnet type rotating electric machine according to the first to fourth embodiments. In FIG. 33, the electric power steering apparatus is provided with a column shaft 23 for transmitting a steering force from the steering wheel 22. The column shaft 23 is connected to a worm gear 24 (details are omitted in the figure and only a gear box is shown). The worm gear 24 transmits the output (torque, rotation speed) of the drive motor 20 controlled by the controller 21 while changing the rotation direction to a right angle, and simultaneously decelerates to increase the assist torque. Reference numeral 25 denotes a handle joint which transmits a steering force and also changes the rotation direction. Reference numeral 26 denotes a steering gear (details are omitted in the figure, only the gear box is shown), and the rotation of the column shaft 23 is decelerated and simultaneously converted into a linear motion of the rack 27 to obtain a required displacement. The wheels are moved by the linear motion of the rack 27, and the direction of the vehicle can be changed.

  In such an electric power steering apparatus, torque pulsation generated by the drive motor 20 is transmitted to the steering wheel 22 via the worm gear 24 and the column shaft 23. Therefore, when the drive motor 20 generates a large torque pulsation, a smooth steering feeling cannot be obtained. However, the torque pulsation can be reduced by incorporating the permanent magnet type rotating electric machine of the first to fourth embodiments as the drive motor 20 of the electric power steering apparatus of the fifth embodiment. For this reason, the steering feeling in the electric power steering apparatus can be improved.

Further, since the drive motor for the electric power steering apparatus is mass-produced, there is a problem that the robustness of the cogging torque with respect to manufacturing variations must be improved. On the other hand, since the cogging torque component resulting from the variation of the rotor can be greatly reduced by mounting the permanent magnet type rotating electrical machine described in the first to fourth embodiments, there is an effect that the robustness is improved. .
Various modifications or alterations of the present invention can be realized without departing from the scope and spirit of the present invention by a related expert, and are not limited to the embodiments described in this specification. Should be understood.

Claims (13)

A rotor having a plurality of magnetic poles constituted by permanent magnets and a rotor core;
A stator comprising an armature winding and a stator core provided with a slot for accommodating the armature winding and having a plurality of teeth facing the rotor;
In the permanent magnet type rotating electrical machine in which an auxiliary groove is provided in a part of the stator core facing the rotor of the teeth,
Protrusions that hold the permanent magnet and are made of a magnetic material are provided on a part of the rotor core in the rotation axis direction,
There are two regions with different magnetic circuit designs in the direction of the rotation axis of the rotor because the cross-sectional shape in the cross section perpendicular to the rotation axis of the rotor having the permanent magnet and the rotor core changes in the direction of the rotation axis. Provided, the auxiliary groove is provided in a partial region in the axial direction of the teeth of the stator core,
The region where the auxiliary groove is provided is a partial region for each region facing the region where the protrusion is provided and the region where the protrusion is not provided. Permanent magnet type rotating electric machine.   The region in which the auxiliary groove is provided is a region that is half the axial length of each region facing the region in which the protrusion is provided and the region in which the protrusion is not provided. The permanent magnet type rotating electrical machine according to claim 1.   The permanent magnet type rotating electrical machine according to claim 1 or 2, wherein a width Wd of the auxiliary groove is larger than an opening width Ws of the slot.   3. The permanent magnet type rotating electric machine according to claim 1, wherein a depth Hd of the auxiliary groove is larger than a thickness Hs of a tip end portion of the teeth.   The permanent magnet type rotating electrical machine according to claim 1 or 2, wherein the auxiliary groove is not provided at an axial end portion of the stator core.   3. The permanent magnet type rotation according to claim 1, wherein the auxiliary groove is provided at one place in a circumferential central portion of the stator core in a portion of the teeth facing the rotor. 4. Electric.   The relation of 0.75 <S / P <1.5 is established, where P is the number of poles of the magnetic pole of the rotor and S is the number of slots of the stator. 2. The permanent magnet type rotating electric machine according to 2.   3. The permanent magnet type according to claim 1, wherein n is a natural number, the number P of the magnetic poles of the rotor is 12n ± 2n, and the number S of the slots of the stator is 12n. Rotating electric machine.   3. The permanent magnet type rotating electric machine according to claim 1, wherein n is a natural number, the number P of the magnetic poles of the rotor is 9n ± n, and the number of slots S of the stator is 9n. . A rotor having a plurality of magnetic poles constituted by permanent magnets and a rotor core;
A stator comprising an armature winding and a stator core provided with a slot for accommodating the armature winding and having a plurality of teeth facing the rotor;
In the permanent magnet type rotating electrical machine in which an auxiliary groove is provided in a part of the stator core facing the rotor of the teeth,
In the rotor, a plurality of magnetic poles are configured by embedding the permanent magnets in a plurality of holes in a rotation axis direction provided in the rotor core,
In the rotor core, a concave groove is formed in a part in the axial direction along the magnetic pole between the magnetic poles adjacent to each other on the surface portion,
There are two regions with different magnetic circuit designs in the direction of the rotation axis of the rotor because the cross-sectional shape in the cross section perpendicular to the rotation axis of the rotor having the permanent magnet and the rotor core changes in the direction of the rotation axis. Provided
The auxiliary groove is provided in a partial region in the axial direction of the teeth of the stator core,
The region where the auxiliary groove is provided is a partial region for each region facing the region where the recessed groove is provided and the region where the recessed groove is not provided. Permanent magnet type rotating electric machine.   The region in which the auxiliary groove is provided is a region that is half of the axial length of each region facing the region in which the recessed groove is provided and the region in which the recessed groove is not provided. The permanent magnet type rotating electric machine according to claim 10.   The axial end surface of the auxiliary groove is located on an end surface perpendicular to the rotation axis between regions having different magnetic circuit designs of the rotor. 11. The permanent magnet type rotating electrical machine according to any one of 11 above. An electric power steering device using the permanent magnet type rotating electric machine according to any one of claims 1 to 12 as a drive motor.

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