JP2019176576A - motor - Google Patents

Abstract

To provide a motor that can prevent a reduction in salient pole ratio.SOLUTION: A protrusion 24 protruding outward in a radial direction is provided at between magnet magnetic pole parts 23 whose poles are different from each other on the outer circumference of a rotor core 21. A motor is configured so as to have a facing relationship in a radial direction between the rotor core 21 and each tooth T at each time while a rotor 14 rotates once such that there is a timing when the number of teeth T that face toward the magnet magnetic pole part 23 and do not face toward the protrusion 24 is more than the number of teeth T that face a pair of the magnet magnetic pole part 23 and the protrusion 24 adjacent in the circumferential direction at the same time.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an interior magnet type motor.

  For example, the motor of Patent Document 1 is an embedded magnet type motor (so-called IPM type motor) in which a magnetic pole portion of a rotor is formed of a permanent magnet embedded in a rotor core. Moreover, the motor of patent document 1 is a full magnet type motor arrange | positioned so that the permanent magnet which forms each magnetic pole part of a rotor may become a different polarity alternately in the circumferential direction.

JP 2008-109799 A

  In the embedded magnet type motor as in Patent Document 1, the reluctance torque can be increased as the salient pole ratio (Lq / Ld), which is the ratio between the q-axis inductance Lq and the d-axis inductance Ld, is larger. However, in the embedded magnet type motor, for example, when the current is increased, the q-axis inductance Lq is likely to be saturated, and the salient pole ratio is thereby reduced.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a motor that can suppress a decrease in salient pole ratio.

  A motor that solves the above problems has a rotating shaft and a rotor core fixed coaxially with the rotating shaft, and a plurality of magnet magnetic pole portions in which permanent magnets are embedded in the rotor core along the circumferential direction. A rotor having an aspect with alternately different poles, a plurality of teeth that are provided along the circumferential direction and that are radially opposed to the outer circumferential surface of the rotor core, and a stator that has a winding wound around each of the teeth. In addition, a protrusion projecting radially outward is provided between the magnet magnetic pole portions having different polarities on the outer peripheral portion of the rotor core, and the rotor core at each time and the respective portions of the rotor make one turn When looking at the radial opposing relationship with the teeth, the number of teeth facing the magnet magnetic pole part and not facing the protrusion is a pair of the magnet magnetic pole parts adjacent in the circumferential direction and the protrusion between them. Same as And it is configured such that there are many becomes timing than the number of the opposing teeth on.

  According to the above aspect, when looking at the radial opposing relationship between the rotor core and each tooth at that time during one revolution of the rotor, the number of teeth facing the magnetic pole part and not facing the protrusion is There is a timing that is greater than the number of teeth facing each other at the same time as a pair of magnet magnetic pole portions adjacent to each other in the circumferential direction and the protrusions therebetween. Thereby, the fall of the salient pole ratio when current is increased can be suppressed (see FIG. 8).

  In the motor, when the radial opposing relationship between the rotor core and the teeth at each time of the rotation of the rotor makes one turn, the teeth of the teeth that face the magnet magnetic pole part and do not face the protrusion There is a timing at which the number and the number of teeth facing each other at the same time as the pair of magnet magnetic pole portions adjacent to each other in the circumferential direction and the protruding portion therebetween are present.

  According to the above aspect, the number of teeth facing the magnet magnetic pole portion and not facing the protrusion is the same as the number of teeth facing the pair of magnet magnetic pole portions adjacent in the circumferential direction and the protrusion therebetween. Therefore, the decrease in salient pole ratio when the current is increased can be more suitably suppressed (see FIG. 8).

  In the motor, when the radial opposing relationship between the rotor core and the teeth at each time of the rotation of the rotor makes one turn, the teeth of the teeth that face the magnet magnetic pole part and do not face the protrusion The number is always larger than the number of teeth facing at the same time as the pair of magnet magnetic pole portions adjacent to each other in the circumferential direction and the protrusions therebetween.

  According to the above aspect, the number of teeth facing the magnet magnetic pole part and not facing the protrusion is always larger than the number of teeth facing the pair of magnet magnetic pole parts adjacent in the circumferential direction and the protrusion therebetween. Therefore, it can contribute to the improvement of the motor output (see FIG. 9).

  In the motor, the opening angles θr of the magnet magnetic pole portions are set to be equal to each other, and the opening angles θs of the facing surfaces of the teeth facing the rotor core in the radial direction are set to be equal to each other. The relationship between the opening angle θs and the opening angle θr of the magnet magnetic pole portion is configured to satisfy θs <θr.

  According to the above aspect, the number of teeth facing the magnet magnetic pole part and not facing the protrusion is larger than the number of teeth facing the pair of magnet magnetic pole parts adjacent in the circumferential direction and the protrusion therebetween. The timing can be configured to exist.

  In the motor, the opening angle θx between the magnet magnetic pole portions adjacent in the circumferential direction is set to be equal to each other, and the relationship between the opening angle θx and the opening angle θs of the facing surface of the teeth is θx <θs. It is configured to satisfy.

  According to the above aspect, since the opening angle θs of the facing surface of the teeth is larger than the opening angle θx between the magnet magnetic pole portions adjacent in the circumferential direction, the teeth do not face only the protrusion. Thereby, it can prevent that the magnetic flux from a tooth | gear flows in into a protrusion only, As a result, an output fall can be suppressed.

In the motor, the teeth have a constant width from an outer end in the radial direction to an inner end in the axial direction.
According to the above aspect, at the end portion (radially inner end portion) of the teeth facing the rotor core, it is possible to make the configuration where the magnetic saturation is difficult to change, and as a result, it is more preferable to reduce the salient pole ratio. Can be suppressed.

  According to the motor of the present invention, the reduction of the salient pole ratio can be suppressed.

(A) Sectional drawing of the motor of embodiment, (b) The top view which partially enlarges and shows the rotor of the same form. The table which shows the opposing relationship of the rotor core and each tooth for every rotation angle of the rotor in the same form. It is sectional drawing of the motor of the same form, Comprising: The figure which shows when the rotation angle (electrical angle) of a rotor is 18 degree | times. Sectional drawing of the motor of the comparative example 1. FIG. The table which shows the opposing relationship of the rotor core and each tooth for every rotation angle of the rotor in the comparative example 1. FIG. Sectional drawing of the motor of the comparative example 2. FIG. The table which shows the opposing relationship of the rotor core and each tooth for every rotation angle of the rotor in the comparative example 2. FIG. The graph which shows the salient pole ratio change according to the electric current change in embodiment and Comparative Examples 1 and 2. FIG. The graph which shows the output change according to the torque change in embodiment and the comparative examples 1 and 2. FIG. The graph which shows the salient pole ratio change according to the torque change in embodiment and the comparative examples 1 and 2. FIG. The top view which shows a part of rotor in the example of a change.

Hereinafter, an embodiment of the motor will be described.
A motor 10 according to this embodiment shown in FIG. 1A is an embedded magnet type (IPM type) brushless motor. The motor 10 is provided with an annular stator 12 fixed to the inner peripheral surface of the motor housing 11, a rotating shaft 13 disposed coaxially with the stator 12, and a rotatable shaft 13. And a rotor 14 disposed on the inner side in the direction. The rotating shaft 13 is rotatably supported with respect to the motor housing 11 via a bearing (not shown).

  The stator 12 has an annular stator core 15, and the outer peripheral surface of the stator core 15 is fixed to the motor housing 11. Note that the stator core 15 is configured by laminating a plurality of core sheets made of, for example, electromagnetic steel plates in the axial direction. The stator core 15 includes a cylindrical annular portion R fixed to the inner peripheral surface of the motor housing 11 and a plurality of teeth T extending radially inward from the inner peripheral surface of the annular portion R. In this embodiment, the number of teeth T (that is, the number of slots) is 12 and has the same shape. That is, the open angles θs described later at the tips (radially inner ends) of the teeth T are equal to each other. Further, the teeth T are provided at equal intervals in the circumferential direction (30-degree intervals in the present embodiment). In addition, the stator core 15 of this embodiment is comprised from the 12 division | segmentation cores 15a divided | segmented for every teeth T. FIG. Each divided core 15a is configured to have one tooth T and a part of the annular portion R.

  Each tooth T has a straight shape having a constant width from the base end portion (outer end portion) in the radial direction to the tip end portion (inner end portion) when viewed in the axial direction. Specifically, as shown in FIG. 1B, the tooth T has a width dimension W perpendicular to the circumferential center line C1 (a straight line perpendicular to the axis L of the rotating shaft 13 and passing through the circumferential center of the tooth T). It is constant over the radial direction. That is, the tooth T of the present embodiment has a configuration that does not include, for example, an extending portion (for example, see the extending portion Tx illustrated in FIG. 4) that extends from the radially inner end of the tooth T to both sides in the circumferential direction. Yes. In addition, the radially inner side surface (tip surface in the extending direction) of each tooth T is a facing surface Ta that faces the outer peripheral surface of the rotor 14 in the radial direction. The facing surface Ta of each tooth T is an arc surface obtained by extending a concentric arc centering on the axis L of the rotating shaft 13 in the axial direction.

  A three-phase winding 16 is wound around each tooth T by concentrated winding. A three-phase power supply voltage is applied to the windings 16 of each phase to form a rotating magnetic field in the stator 12, and the rotor 14 is rotated by the interaction between the rotating magnetic field and the magnetic field on the rotor 14 side. Yes.

  As shown in FIGS. 1A and 1B, the rotor 14 disposed inside the stator 12 includes a columnar (circular cross section) rotor core 21 that is coaxially fixed to the rotating shaft 13, and a rotor core 21. And a plurality of permanent magnets 22 embedded therein. The rotor core 21 is configured by laminating a plurality of core sheets made of, for example, electromagnetic steel plates in the axial direction.

  Ten permanent magnets 22 having the same shape are used for the rotor 14 of the present embodiment, and the permanent magnets 22 are arranged at equal intervals in the circumferential direction (36-degree intervals) in the vicinity of the outer peripheral surface of the rotor core 21. . And each permanent magnet 22 forms the magnet magnetic pole part 23 which becomes a different polarity alternately in the circumferential direction in the outer peripheral surface of the rotor core 21, and the pole number (the number of the magnet magnetic pole parts 23) of the rotor 14 is 10 poles. Yes. The rotor 14 is a full magnet type rotor having permanent magnets 22 in each of all the magnetic poles. Each permanent magnet 22 is made of, for example, a sintered magnet or a bonded magnet (such as a plastic magnet or a rubber magnet) that is molded and solidified by mixing magnet powder with resin. Further, the permanent magnet 22 of the present embodiment has a substantially rectangular parallelepiped shape, and is provided so that the widest surface thereof is orthogonal to the radial direction of the rotor 14.

  The shape of each magnet magnetic pole portion 23 (the shape of the permanent magnet 22 and the shape of the portion of the rotor core 21 in the vicinity where the permanent magnet 22 is embedded) has the same shape. That is, the later-described open angles θr of the magnet magnetic pole portions 23 are equal to each other. In each magnet magnetic pole portion 23, the magnetic pole center lines Lp in the circumferential direction are set at equal intervals in the circumferential direction (36 ° intervals).

  The rotor core 21 includes a protrusion 24 protruding outward in the radial direction between the magnet magnetic pole parts 23 of different polarities on the outer peripheral part, and between the protrusion 24 and the adjacent magnet magnetic pole part 23. It has a pair of recesses 25 that are provided radially inward. In other words, each magnet magnetic pole portion 23 is configured to be adjacent to the protrusion 24 via the recess 25 on both sides in the circumferential direction. The protrusions 24 have the same shape as each other and are provided at equal intervals in the circumferential direction (36-degree intervals). The protrusion 24 and the concave portions 25 adjacent to the protrusion 24 are formed so as to be bilaterally symmetric (symmetric in the circumferential direction) with respect to the circumferential center of the protrusion 24.

Next, dimension setting in the circumferential direction at each of the magnetic pole portion 23, the protrusion 24, the recess 25, and the tip end portion (radially inner end portion) of the tooth T will be described with reference to FIG.
The opening angle of the tip of the tooth T (the angular width between one end and the other end of the opposing surface Ta around the axis L) is “θs”, and the opening angle of the magnet magnetic pole portion 23 (centering on the axis L). The angle width between one end and the other end of the outer circumferential surface of the magnet magnetic pole portion 23 is “θr”, and θs <θr is set. In addition, the circumferential direction one end and the other end of the outer peripheral surface of the magnet magnetic pole part 23 that define the open angle θr are set as a boundary part with a magnetoresistive part adjacent to the circumferential direction (in this embodiment, the gap of the recess 25). It is desirable.

  Further, the opening angle between the magnetic pole portions 23 adjacent to each other in the circumferential direction (magnet magnetic pole portions 23 having different polarities) (the opening angle θx between the magnetic pole portions) is the opening angle of the protrusion 24 (the protrusion around the axis L). The angle width of the radially outer end of the portion 24 is “θt”, and the opening angle of one recess 25 (the angle width of the radially outer end of the recess 25 around the axis L) is “θg”. = Θt + (θg × 2). The opening angle θx between the magnetic pole parts is set to be smaller than the opening angle θs at the tip of the tooth T. That is, in the present embodiment, it is set to satisfy θx <θs <θr.

  FIG. 2 shows that the rotor core 21 and each tooth T (opposing surface Ta) are sometimes rotated when the rotor 14 is rotated in one circumferential direction (counterclockwise direction in FIG. 1A) in the motor 10 of the present embodiment. It is a table | surface which shows the opposing relationship of the radial direction. In addition, in order to identify and describe each tooth T individually, as shown in FIG. 1A, the teeth numbers “1” to “12” are sequentially provided in the counterclockwise direction in the circumferential direction with respect to each tooth T. The tooth number corresponds to the tooth number in the table of FIG.

  In the table of FIG. 2, each of the teeth from “1” to “12” at each position when the rotor 14 is rotated counterclockwise by 6 degrees in electrical angle (1.2 degrees in mechanical angle). T indicates which pattern is “A”, “B”, and “C”, and the number of teeth of each pattern A to C for each position (for each rotation angle). The pattern A is a pattern in which the facing surface Ta of the tooth T faces the magnet magnetic pole part 23 and does not face the protrusion 24. The pattern B is a pattern in which the facing surface Ta of the tooth T faces the one magnetic pole portion 23 and the protrusion 24 simultaneously. The pattern C is a pattern in which the facing surface Ta of the tooth T faces the pair of magnet magnetic pole portions 23 (magnet magnetic pole portions 23 having different polarities) adjacent to each other in the circumferential direction and the protrusion 24 therebetween. Note that the pattern B does not include the pattern C.

  FIG. 1A shows the motor 10 when the rotation angle (electrical angle) of the rotor 14 is 6 degrees. At this time, the teeth T having the numbers “1” and “7” respectively face the magnet magnetic pole portion 23 in front of each other (the circumferential centers of the teeth T and the magnet magnetic pole portion 23 coincide with each other). Each of the teeth T having the numbers “4” and “10” is opposed to the protrusion 24 in front of each other (the circumferential centers of the teeth T and the protrusion 24 coincide with each other). Then, the opposing relationship of each tooth T with the rotor core 21 will be described with reference to each pattern A to C. The teeth T with numbers “1” and “7” become the pattern A, and the numbers “2”, “3”, Teeth T of “5”, “6”, “8”, “9”, “11”, “12” are pattern B, and teeth T of numbers “4” and “10” are pattern C. . That is, the number of teeth in each of the patterns A to C has a relationship of “2” − “8” − “2”.

  When the rotor 14 is rotated counterclockwise from this state, there is a timing when the number of teeth T of the pattern A increases to four. For example, FIG. 3 is a view when the rotation angle of the rotor 14 in the table of FIG. 2 is 18 degrees. At this time, the four teeth T of the numbers “1”, “6”, “7”, “12” become the pattern A, and the numbers “2”, “3”, “5”, “8”, “9”. , “11” becomes the pattern B, and the two teeth T having the numbers “4” and “10” become the pattern C. That is, the two teeth T having the numbers “6” and “12” are changed from the pattern C to the pattern A, and the number of the teeth T of the pattern A is increased. After the rotation angle (18 degrees), the number of teeth of each of the patterns A to C becomes a relationship of “4”-“6”-“2”, and the relationship remains unchanged until the rotation angle is 30 degrees.

  Thus, when the rotation angle of the rotor 14 is 6 degrees and 12 degrees, the number of teeth of each of the patterns A to C is “2” − “8” − “2”, and then the rotation angle is 18 degrees, 24 degrees, 30 The number of teeth of each pattern A to C is “4” − “6” − “2”. The change in the number of teeth in each of the patterns A to C has a periodicity of every 30 degrees in electrical angle, and the period of every 30 degrees is repeated for one round (360 degrees) in electrical angle. In addition, since the rotor 14 of this embodiment is comprised by 10 poles, it will be 1 mechanical angle of the rotor 14 for 5 electrical angles (1800 degrees).

[Comparative Example 1]
In FIG. 4, a configuration in which the opening angle θs of the tip portion (opposing surface Ta) of the tooth T is larger than that of the present embodiment is shown as a comparative example 1. As the rotor 14 in the comparative example 1, the same rotor 14 as that of the present embodiment is used. In the configuration of Comparative Example 1, the relationship between the open angle θs of the teeth T and the magnet magnetic pole portion 23 of the rotor 14 is θr <θs. Each tooth T of the comparative example 1 has an extending portion Tx extending from the radially inner end portion to both sides in the circumferential direction, whereby the facing surface Ta (opening angle θs) to the rotor core 21 is wide. It is secured.

  FIG. 5 is a table (a table summarized in the same manner as FIG. 2) showing the opposing relationship of each tooth T with respect to the rotor core 21 in Comparative Example 1. Also in the comparative example 1, the change in the number of teeth of each of the patterns A to C has a periodicity of every 30 degrees in electrical angle, and the number of teeth of the patterns B and C is “8” − [2]. And “6”-[4], the number of teeth of the pattern A is always 2 while the rotor 14 rotates 360 degrees in electrical angle. That is, in Comparative Example 1, there is no timing at which the number of teeth in pattern A is greater than the number of teeth in pattern C.

[Comparative Example 2]
In FIG. 6, a configuration in which the opening angle θs of the tip portion (opposing surface Ta) of the tooth T is smaller than the configuration of FIG. As the rotor 14 in the comparative example 2, the same rotor 14 as that of the present embodiment is used. Also in the configuration of Comparative Example 2, the relationship between the opening angle θs of the teeth T and the opening angle θx between the magnetic pole portions of the rotor 14 is θx <θs. Moreover, the teeth T of Comparative Example 2 have a straight shape having a constant width over the entire radial direction, similarly to the teeth T of the above-described embodiment (configuration of FIG. 1A).

  FIG. 7 is a table (a table summarized in the same manner as FIG. 2) showing the opposing relationship of each tooth T with respect to the rotor core 21 in Comparative Example 2. Also in the comparative example 2, the change in the number of teeth of each of the patterns A to C has a periodicity of every 30 degrees in electrical angle, and the number of teeth of the patterns B and C is “6” − [2]. And “8”-[0], the number of teeth of the pattern A is always 4 while the rotor 14 rotates 360 degrees in electrical angle. In other words, in the comparative example 2, the number of teeth of the pattern A is always larger than the number of teeth of the pattern C while the rotor 14 rotates 360 degrees in electrical angle (that is, while the rotor 14 makes one round in mechanical angle). Many.

The operation of this embodiment will be described.
As shown in FIG. 8, when the current supplied to the winding 16 is increased, in the embodiment (configuration in FIG. 1A) and the comparative example 2, the q-axis inductance Lq and the d-axis inductance Ld The degree of decrease in the salient pole ratio (Lq / Ld), which is the ratio, is smaller than that in Comparative Example 1. In the embodiment and the comparative example 2, the number of teeth T of the pattern A (the teeth T facing the magnet magnetic pole portion 23 and not facing the protrusion 24) is larger than that of the comparative example 1, so that when d-axis current is input The amount of magnetic flux flowing into the protrusion 24 (q-axis) can be reduced. Thereby, since the fall of the q-axis inductance Lq by the magnetic saturation of the protrusion 24 when the current is increased can be suppressed, the degree of decrease in the salient pole ratio when the current is increased is higher than that of the first embodiment. This is considered to be less in Comparative Example 2. In the embodiment and the comparative example 2, since a magnetic circuit straddling the d-axis and the q-axis is hardly formed, magnetic mutual interference is hardly generated between the d-axis and the q-axis. As a result, the difference between the q-axis inductance Lq and the d-axis inductance Ld can be ensured more suitably, and the decrease in the salient pole ratio can be more suitably suppressed.

  Further, as shown in FIG. 9, in the embodiment and the comparative example 2, the output (the rotational speed when the torque is the same) is improved as compared with the comparative example 1. This is considered to be due to the fact that in the embodiment and the comparative example 2, the degree of decrease in the salient pole ratio when the current is increased is suppressed as compared with the comparative example 1.

  In the comparison between the configuration of the embodiment and Comparative Example 2, as shown in FIG. 8, the configuration of the embodiment is smaller with respect to the degree of decrease in the salient pole ratio. Further, as shown in FIG. 9, the comparative example 2 is larger with respect to the output (the number of revolutions when the torque is the same).

  As shown in FIG. 10, when the torque is changed greatly, the salient pole ratio in the comparative example 2 is larger in the embodiment and the comparative example 2. This is a phenomenon that occurs because the d-axis magnetic saturation tends to proceed when the q-axis current is large (that is, the d-axis inductance Ld tends to decrease) as the opening angle θs of the tooth T (opposing surface Ta) is small. It is believed that there is.

The effect of this embodiment will be described.
(1) Between the magnetic pole portions 23 of different polarities on the outer peripheral portion of the rotor core 21, a protrusion 24 that protrudes radially outward is provided. In the present embodiment and Comparative Example 2, when the opposing relationship in the radial direction between the rotor core 21 and each tooth T during each round of the rotor 14 is seen, it faces the magnetic pole portion 23 and protrudes. The number of teeth T (the teeth T of the pattern A) that are not opposed to the portion 24 is the number of teeth T (the teeth T of the pattern C) that are simultaneously opposed to the pair of magnet magnetic pole portions 23 adjacent to each other in the circumferential direction and the protrusion 24 therebetween. There are more timings. Thereby, the fall of salient pole ratio (Lq / Ld) when an electric current is enlarged can be suppressed (refer FIG. 8). As a result, the reluctance torque can be improved. In addition, by adopting the configuration of the present embodiment and comparative example 2 in which the decrease in salient pole ratio is suppressed in a motor equipped with disturbance injection type sensorless control that eliminates the position sensor as a solution to the need for miniaturization. The error of the rotational position of the rotor 14 can be controlled with little.

  (2) In the present embodiment, when the radial opposing relationship between the rotor core 21 and each tooth T at that time during one rotation of the rotor 14 is seen, the magnet 14 is opposed to the magnetic pole portion 23 and the protrusion 24. The number of teeth T not facing each other (the teeth T of pattern A) is the same as the number of teeth T facing each other at the same time as the pair of magnet magnetic pole portions 23 adjacent to each other in the circumferential direction and the protrusions 24 therebetween. There is a timing of (2 in this embodiment). For this reason, the fall of the salient pole ratio when the current is increased can be more suitably suppressed (see FIG. 8).

  (3) In Comparative Example 2, when the opposing relationship in the radial direction between the rotor core 21 and each tooth T at that time during one round of the rotor 14 is seen, the magnet pole portion 23 is opposed to the protrusion 24. The number of teeth T (the teeth T of the pattern A) that are not opposed to each other is always larger than the number of teeth T (the teeth T of the pattern C) that are simultaneously opposed to the pair of magnet magnetic pole portions 23 adjacent to each other in the circumferential direction and the protrusion 24 therebetween. Many. For this reason, it can contribute to the output improvement of the motor 10 (refer FIG. 9).

  (4) In the present embodiment and Comparative Example 2, the relationship between the open angle θs of the opposing surface Ta (radial inner side surface) facing the rotor core 21 in each tooth T in the radial direction and the open angle θr of each magnetic pole portion 23. Is configured to satisfy θs <θr. According to the above aspect, the number of the teeth T (the teeth T of the pattern A) facing the magnet magnetic pole part 23 and not facing the protrusion 24 is the pair of magnet magnetic pole parts 23 adjacent in the circumferential direction and the protrusions therebetween. 24, it is possible to configure so that there is a timing that is greater than the number of teeth T (tooth T of pattern C) facing each other.

  (5) In this embodiment and Comparative Example 2, the opening angle between the magnetic pole portions 23 adjacent in the circumferential direction (opening angle θx between the magnetic pole portions) is set to be equal to each other, and the opening angle θx between the magnetic pole portions is The relationship with the open angle θs of the facing surface Ta of the tooth T is configured to satisfy θx <θs. For this reason, when the rotor 14 rotates, the facing surface Ta of the tooth T does not face only the protrusion 24. Thereby, it can prevent that the magnetic flux from the teeth T flows in into only the protrusion 24, As a result, an output fall can be suppressed.

  (6) In this embodiment and Comparative Example 2, the teeth T have a certain width from the radially outer end to the inner end in the axial direction (straight shape). That is, the teeth T of the present embodiment and Comparative Example 2 are not shaped like the Comparative Example 1 in which the tips of the teeth expand in the circumferential direction (shapes having the extending portions Tx). As a result, it is possible to make a configuration in which the portion where the magnetic saturation is difficult to change at the tip portion (radially inner end portion) of the teeth T facing the rotor core 21, and as a result, the salient pole ratio when the current is increased. It is possible to more suitably suppress the decrease in the above. Moreover, when compared with the configuration in which the opening angle θs of the facing surface Ta is the same in the tooth T having the extension portion Tx as in the comparative example 1, the straight tooth T as in the above embodiment and the comparative example 2 is used. Since the width of the intermediate portion in the radial direction of the teeth T can be secured, the magnetic saturation itself at the teeth T can be suppressed, and the output can be improved.

This embodiment can be implemented with the following modifications. The present embodiment and the following modifications can be implemented in combination with each other within a technically consistent range.
-You may change the rotor 14 of the said embodiment and the comparative example 2 to the rotor 30 as shown in FIG. Note that, in the configuration of the figure, the same reference numerals are given to the same configurations as those in the above embodiment, and the detailed description thereof is omitted. In the rotor 14 of the above embodiment and the comparative example 2, the magnetoresistive portion between the magnet magnetic pole portion 23 and the protrusion 24 adjacent to each other in the circumferential direction is the concave portion 25 recessed inward in the radial direction. The configuration changes this. More specifically, in the configuration shown in the figure, the portion 21a on the outer side in the radial direction of the permanent magnet 22 in the rotor core 21 (each magnetic pole portion 23) and the protrusions 24 adjacent on both sides in the circumferential direction of the portion 21a are bridged. They are connected together via the part 31. In other words, the bridge portions 31 extend in the circumferential direction from the respective protrusions 24 toward the portions 21 a of the magnet magnetic pole portions 23 on both sides in the circumferential direction, and are connected to the portions 21 a of both the magnet magnetic pole portions 23. On the radially inner side of each bridge portion 31, a gap portion 32 that is in contact with the circumferential side surface of the permanent magnet 22 is provided. Each bridge portion 31 is crushed in the axial direction or the radial direction and plastically deformed, for example, so that the magnetic resistance is higher than that of the other core portion (the portion 21a or the protrusion 24), and functions as a magnetoresistive portion. To do. In such a configuration, one end and the other end of the outer peripheral surface of the magnet magnetic pole part 23 (part 21a) that define the opening angle θr of the magnet magnetic pole part 23 are the magnet magnetic pole part 23 (part 21a) and the magnetoresistive part. It is desirable to set the boundary portion with a certain bridge portion 31.

  In the above embodiment and comparative example 2, the portions 21b (portions between the permanent magnet 22 and the recess 25) on both sides in the circumferential direction of the permanent magnet 22 in the rotor core 21 are crushed, for example, in the axial direction or the radial direction (plastic deformation) ), The magnetic resistance of the portion 21b may be increased.

  In the above embodiment and the comparative example 2, each tooth T has a straight shape (a shape having a constant width from the outer end in the radial direction to the inner end). The extending portion Tx as in Comparative Example 1 may be provided without changing the angle θs.

  The stator core 15 is divided into the same number as the number of teeth T (a structure composed of each divided core 15a). However, the present invention is not limited to this, and the stator core 15 including the annular portion R and each tooth T is integrally formed. Also good.

  The number of poles of the rotor 14 (number of magnet magnetic pole portions 23) and the number of slots of the stator 12 (number of teeth T) in the above embodiment and comparative example 2 are examples, and can be appropriately changed to 14 poles: 12 slots or the like. is there.

  DESCRIPTION OF SYMBOLS 10 ... Motor, 12 ... Stator, 13 ... Rotating shaft, 14 ... Rotor, 15 ... Stator core, T ... Teeth, Ta ... Opposite surface, 16 ... Winding, 21 ... Rotor core, 22 ... Permanent magnet, 23 ... Magnet magnetic pole part, 24 ... protrusion, 30 ... rotor.

Claims (6)

A rotation axis;
A rotor having a rotor core fixed coaxially with respect to the rotation shaft, and having a plurality of magnet magnetic pole portions in which permanent magnets are embedded in the rotor core alternately in a different direction along the circumferential direction;
A plurality of teeth provided along the circumferential direction and facing the outer circumferential surface of the rotor core in the radial direction, and a stator having a winding wound around each of the teeth,
Between each of the magnet magnetic pole parts of different polarities in the outer peripheral part of the rotor core, a protrusion protruding radially outward is provided,
The number of teeth facing the magnet magnetic pole portion and not facing the protrusion when the radial facing relationship between the rotor core and the teeth at that time during one rotation of the rotor A motor configured to have a timing that is greater than the number of teeth facing each other at the same time as a pair of magnet magnetic pole portions adjacent to each other in the direction and the protrusion therebetween.   The number of teeth facing the magnet magnetic pole part and not facing the protrusion, and the number of teeth when the radial facing relationship between the rotor core and the teeth at that time of the rotor makes one turn, The motor according to claim 1, wherein there is a timing at which a pair of magnet magnetic pole portions adjacent to each other in a direction and the number of teeth facing each other at the same time as the protrusions therebetween are the same.   The number of teeth facing the magnet magnetic pole portion and not facing the protrusion when the radial facing relationship between the rotor core and the teeth at that time during one rotation of the rotor 2. The motor according to claim 1, wherein the motor is always larger than the number of teeth facing each other simultaneously with the pair of magnet magnetic pole portions adjacent to each other in the direction and the protrusion therebetween. The opening angles θr of the magnet magnetic pole portions are set equal to each other,
The opening angles θs of the opposing surfaces in the teeth facing the rotor core in the radial direction are set to be equal to each other,
The motor according to any one of claims 1 to 3, wherein a relationship between an opening angle θs of the facing surface of the teeth and an opening angle θr of the magnet magnetic pole portion satisfies θs <θr. .   The opening angles θx between the magnet magnetic pole portions adjacent to each other in the circumferential direction are set to be equal to each other so that the relationship between the opening angle θx and the opening angle θs of the facing surface of the teeth satisfies θx <θs. The motor according to claim 4, wherein the motor is configured.   The motor according to any one of claims 1 to 5, wherein the teeth have a constant width from an outer end portion in a radial direction to an inner end portion in an axial view.