JP2021119741A - 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 embedded magnet type motor.

For example, the motor of Patent Document 1 is an embedded magnet type motor (so-called IPM type motor) in which the magnetic pole portion of the rotor is formed of a permanent magnet embedded in the rotor core. Further, the motor of Patent Document 1 is a full magnet type motor in which permanent magnets forming each magnetic pole portion of the rotor are arranged so as to be alternately different poles in the circumferential direction.

Japanese Unexamined Patent Publication No. 2008-109799

An object of the present invention is to have a rotating shaft and a rotor core coaxially fixed to the rotating shaft, and alternating 10-pole magnet magnetic poles in which a permanent magnet is embedded in the rotor core along the circumferential direction. A rotor having different polarities, 12 teeth provided along the circumferential direction and facing the outer peripheral surface of the rotor core in the radial direction, and a three-phase concentrated winding around each of the teeth. Provided is a motor provided with a stator having a winding, and a protrusion protruding outward in the radial direction is provided between each of the magnet magnetic pole portions having different poles on the outer peripheral portion of the rotor core. be.

A motor that solves the above problems has a rotating shaft and a rotor core that is coaxially fixed to the rotating shaft, and has a 10-pole magnet magnetic pole portion in which a permanent magnet is embedded in the rotor core along the circumferential direction. Rotors that are alternately provided with different poles, 12 teeth that are provided along the circumferential direction and face the outer peripheral surface of the rotor core in the radial direction, and three-phase concentrated winding around each of the teeth. A stator having a rotated winding is provided, and a protrusion protruding outward in the radial direction is provided between each of the magnet magnetic pole portions having different poles on the outer peripheral portion of the rotor core, and the magnet magnetic pole portions are provided. The opening angles θr of the two are set to be equal to each other, the opening angles θs of the facing surfaces facing the rotor core in the radial direction in each tooth are set to be equal to each other, and the opening angles between the magnet magnetic pole portions adjacent to each other in the circumferential direction are set to be equal to each other. θx is set to be equal to each other, and the relationship between the opening angle θs of the facing surfaces of the teeth, the opening angle θr of the magnet magnetic poles, and the opening angle θx between the magnet magnetic poles is θx <θs <θr. It is configured to meet.

A motor that solves the above problems has a rotating shaft and a rotor core that is coaxially fixed to the rotating shaft, and has a 10-pole magnet magnetic pole portion in which a permanent magnet is embedded in the rotor core along the circumferential direction. Rotors that are alternately provided with different poles, 12 teeth that are provided along the circumferential direction and face the outer peripheral surface of the rotor core in the radial direction, and three-phase concentrated winding around each of the teeth. A stator having a rotated winding is provided, and a protrusion protruding radially outward is provided between each of the magnet magnetic pole portions having different poles on the outer peripheral portion of the rotor core, and the rotor makes one round. When looking at the radial facing relationship between the rotor core and each tooth at that time, the number of teeth facing the magnet magnetic pole portion and not facing the protruding portion is a pair adjacent to each other in the circumferential direction. It is configured so that there is a timing that is larger than the number of teeth facing each other at the same time as the magnet magnetic pole portion and the protrusion portion between them.

(A) A cross-sectional view of the motor of the embodiment, and (b) a plan view showing a part of the rotor of the same embodiment in an enlarged manner. The figure which shows the facing relationship between the rotor core and each tooth for each rotation angle of a rotor in the same form. It is a cross-sectional view of the motor of the same form, and is the figure which shows when the rotation angle (electrical angle) of a rotor is 18 degrees. FIG. 3 is a cross-sectional view of the motor of Comparative Example 1. The chart which shows the facing relationship between the rotor core and each tooth for each rotation angle of the rotor in the comparative example 1. FIG. FIG. 3 is a cross-sectional view of the motor of Comparative Example 2. The figure which shows the facing relationship between the rotor core and each tooth for each rotation angle of the rotor in the comparative example 2. FIG. The graph which shows the salient pole ratio change according to the current change in Embodiment and Comparative Examples 1 and 2. The graph which shows the output change according to the torque change in Embodiment and Comparative Examples 1 and 2. The graph which shows the salient pole ratio change according to the torque change in Embodiment and Comparative Examples 1 and 2. The plan view which shows a part of the rotor in the modification example.

Hereinafter, one embodiment of the motor will be described.
The motor 10 of the present embodiment shown in FIG. 1A is an embedded magnet type (IPM type) brushless motor. The motor 10 is provided integrally with an annular stator 12 fixed to the inner peripheral surface of the motor housing 11, a rotating shaft 13 arranged coaxially with the stator 12, and a rotating shaft 13, and has a diameter of the stator 12. It includes a rotor 14 arranged inside in the direction. The rotary shaft 13 is rotatably supported by 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. The stator core 15 is formed by laminating a plurality of core sheets made of, for example, electrical steel sheets 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. The number of teeth T (that is, the number of slots) of the present embodiment is 12 and has the same shape as each other. That is, the opening angles θs of the tip portions (diameter inner end portions) of the teeth T, which will be described later, 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). The stator core 15 of the present embodiment is composed of 12 divided cores 15a divided for each tooth T. Each split core 15a is configured to have one tooth T and a portion of the annular portion R.

Each tooth T has a straight shape having a constant width from the base end portion (outer end portion) to the tip end portion (inner end portion) in the radial direction in the axial direction. Specifically, as shown in FIG. 1B, the teeth T has a width dimension W orthogonal to the circumferential center line C1 (a straight line orthogonal to the axis L of the rotation axis 13 and passing through the circumferential center of the teeth T). , It is constant over the radial direction. That is, the teeth T of the present embodiment has a configuration that does not have, for example, an extension portion (see, for example, the extension portion Tx shown in FIG. 4) extending from the radial inner end portion of the teeth T to both sides in the circumferential direction. There is. The radial inner 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 in which arcs of concentric circles centered on the axis L of the rotating shaft 13 extend in the axial direction.

A three-phase winding 16 is wound around each tooth T in a concentrated winding. Then, 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. There is.

As shown in FIGS. 1A and 1B, the rotor 14 arranged inside the stator 12 is a columnar (circular cross section) rotor core 21 fixed coaxially with the rotating shaft 13 and a rotor core 21. It is provided with a plurality of permanent magnets 22 embedded inside. The rotor core 21 is formed by laminating a plurality of core sheets made of, for example, electrical steel sheets in the axial direction.

In the rotor 14 of the present embodiment, ten permanent magnets 22 having the same shape are used, and the permanent magnets 22 are arranged at equal intervals (36 degree intervals) in the circumferential direction in the vicinity of the outer peripheral surface of the rotor core 21. .. Then, each permanent magnet 22 forms magnet magnetic pole portions 23 having different poles alternately in the circumferential direction on the outer peripheral surface of the rotor core 21, and the number of poles of the rotor 14 (the number of magnet magnetic pole portions 23) is set to 10 poles. There is. Further, the rotor 14 is a full magnet type rotor provided with permanent magnets 22 on each of its magnetic poles. Each permanent magnet 22 is made of, for example, a sintered magnet or a bond magnet (plastic magnet, rubber magnet, etc.) formed by mixing magnet powder with a resin and solidifying it. Further, the permanent magnet 22 of the present embodiment has a substantially rectangular parallelepiped shape, and its widest surface is provided so as to be 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 as each other. That is, the opening angles θr of each magnet magnetic pole portion 23, which will be described later, are equal to each other. Further, in each magnet magnetic pole portion 23, the magnetic pole center lines Lp in the circumferential direction are set at equal intervals (36 degree intervals) in the circumferential direction.

The rotor core 21 has a protrusion 24 protruding outward in the radial direction between the magnet magnetic poles 23 having different poles on the outer peripheral portion thereof, and between the protrusion 24 and the magnet magnetic poles 23 on both sides of the protrusion 24, respectively. It has a pair of recesses 25 that are provided and are recessed inward in the radial direction. That is, 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 (36 degree intervals) in the circumferential direction. The protrusion 24 and the recesses 25 on both sides thereof are formed so as to be symmetrical (symmetrical in the circumferential direction) with respect to the center of the protrusion 24 in the circumferential direction.

Next, the dimensional setting in the circumferential direction at each of the magnet magnetic pole portion 23, the protrusion 24, the recess 25, and the tip portion (diameter inner end portion) of the tooth T will be described with reference to FIG. 1 (b).
The opening angle of the tip of the tooth T (angle width between one end and the other end in the circumferential direction of the facing surface Ta centered on the axis L) is "θs", and the opening angle of the magnet magnetic pole portion 23 (centered on the axis L). The angular width between one end and the other end in the circumferential direction of the outer peripheral surface of the magnet magnetic pole portion 23) is set to “θr” and θs <θr. It should be noted that one end and the other end in the circumferential direction of the outer peripheral surface of the magnet magnetic pole portion 23 that defines the opening angle θr are set at the boundary portion with the magnetic resistance portion (the gap of the recess 25 in the present embodiment) adjacent in the circumferential direction. Is desirable.

Further, the opening angle (opening angle θx between the magnetic pole portions) between the magnet magnetic pole portions 23 adjacent to each other in the circumferential direction (magnet magnetic pole portions 23 having different poles from each other) is the opening angle of the protruding portion 24 (the protrusion centered on the axis L). The angular width of the radial outer end of the portion 24) is "θt", and the opening angle of one recess 25 (the angular width of the radial outer end of the recess 25 centered on the axis L) is "θg". = Θt + (θg × 2). The opening angle θx between the magnetic poles is set to be smaller than the opening angle θs at the tip of the teeth T. That is, in this embodiment, it is set so that θx <θs <θr.

FIG. 2 shows the rotor core 21 and each tooth T (opposing surface Ta) 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 which shows the facing relationship in the radial direction of. In addition, in order to individually identify and explain each tooth T, as shown in FIG. 1A, the tooth numbers of "1" to "12" are sequentially arranged counterclockwise in the circumferential direction with respect to each tooth T. Is attached, and the teeth number corresponds to the teeth number in the table of FIG.

In the table of FIG. 2, each tooth number "1" to "12" is displayed at each position when the rotor 14 is rotated counterclockwise by 6 degrees in the electric angle (1.2 degrees in the mechanical angle). It shows which pattern T is "A", "B", and "C", and shows 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 teeth T faces the magnet magnetic pole portion 23 and does not face the protrusion 24. The pattern B is a pattern in which the facing surface Ta of the teeth T faces one magnet magnetic pole portion 23 and the protruding portion 24 at the same time. The pattern C is a pattern in which the facing surfaces Ta of the teeth T face each other at the same time as a pair of magnet magnetic pole portions 23 (magnet magnetic pole portions 23 having different poles from each other) adjacent to each other in the circumferential direction and a protrusion 24 between them. The pattern B does not include the pattern C.

FIG. 1A shows a motor 10 when the rotation angle (electrical angle) of the rotor 14 is 6 degrees. At this time, the teeth T of the numbers "1" and "7" face each other directly in front of the magnet magnetic pole portion 23 (the centers of the teeth T and the magnet magnetic pole portion 23 in the circumferential direction coincide with each other). Further, the teeth T of the numbers "4" and "10" face each other directly in front of the protrusion 24 (the centers of the teeth T and the protrusion 24 in the circumferential direction coincide with each other). Then, when the facing relationship of each tooth T with the rotor core 21 at this time is explained in each pattern A to C, the tooth T of the numbers "1" and "7" becomes the pattern A, and the numbers "2", "3", The teeth T of "5", "6", "8", "9", "11", and "12" are pattern B, and the teeth T of numbers "4" and "10" are pattern C. .. That is, the number of teeth of each pattern 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 diagram 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", and "12" become the pattern A, and the numbers "2", "3", "5", "8", and "9". , 6 teeth T of "11" become pattern B, and 2 teeth T of numbers "4" and "10" become pattern C. That is, the two teeth T of the numbers "6" and "12" change from the pattern C to the pattern A, and the number of the teeth T of the pattern A increases. At this rotation angle (18 degrees), the number of teeth of each pattern A to C has a relationship of "4"-"6"-"2", and the relationship remains the same until the rotation angle is 30 degrees.

In this way, when the rotation angles of the rotor 14 are 6 degrees and 12 degrees, the number of teeth of each pattern A to C becomes "2"-"8"-"2", and then the rotation angles are 18 degrees, 24 degrees and 30 degrees. The number of teeth of each pattern A to C becomes "4"-"6"-"2". Then, the change in the number of teeth of each pattern A to C has a periodicity of every 30 degrees at the electric angle, and the cycle of every 30 degrees is repeated for one round (360 degrees) at the electric angle. Since the rotor 14 of the present embodiment is composed of 10 poles, 5 electric angles (1800 degrees) are equivalent to 1 mechanical angle of the rotor 14.

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

FIG. 5 is a table showing the facing relationship of each tooth T with respect to the rotor core 21 in Comparative Example 1 (a table summarized in the same manner as in FIG. 2). Also in Comparative Example 1, the change in the number of teeth of each pattern A to C has a periodicity of every 30 degrees in the electric angle, and the number of teeth of patterns B and C is "8"-[2]. Although there are cases of "6"-[4], the number of teeth of the pattern A is always two while the rotor 14 rotates 360 degrees at the electric angle. That is, in Comparative Example 1, there is no timing when the number of teeth of pattern A becomes larger than the number of teeth of pattern C.

[Comparative Example 2]
FIG. 6 shows a configuration in which the opening angle θs of the tip portion (opposing surface Ta) of the teeth T is smaller than the configuration of FIG. 1 (a) as Comparative Example 2. As the rotor 14 in Comparative Example 2, the same rotor 14 as in the present embodiment is used. Further, 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 poles of the rotor 14 is θx <θs. Further, the tooth T of the comparative example 2 has a straight shape having a constant width over the entire radial direction, similarly to the tooth T of the above embodiment (configuration of FIG. 1A).

FIG. 7 is a table showing the facing relationship of each tooth T with respect to the rotor core 21 in Comparative Example 2 (a table summarized in the same manner as in FIG. 2). Also in Comparative Example 2, the change in the number of teeth of each pattern A to C has a periodicity of every 30 degrees in the electric angle, and the number of teeth of 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 at the electric angle. That is, in Comparative Example 2, the number of teeth of pattern A is always larger than the number of teeth of pattern C while the rotor 14 rotates 360 degrees at the electric angle (that is, while the rotor 14 makes one revolution at the 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 of FIG. 1A) and 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 Comparative Example 2, since the number of teeth T (teeth T facing the magnet magnetic pole portion 23 and not facing the protrusion 24) of the pattern A is larger than that of Comparative Example 1, when the d-axis current is input. The amount of magnetic flux flowing into the protrusion 24 (q-axis) can be reduced. As a result, it is possible to suppress a decrease in the q-axis inductance Lq due to magnetic saturation of the protrusion 24 when the current is increased, so that the degree of decrease in the salient pole ratio when the current is increased is higher than that in Comparative Example 1 It is considered that the number is reduced in Comparative Example 2. Further, in the embodiment and Comparative Example 2, since it is difficult to form a magnetic circuit straddling the d-axis and the q-axis, it is difficult for magnetic mutual interference to occur 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 more preferably secured, and the decrease in the salient pole ratio can be more preferably suppressed.

Further, as shown in FIG. 9, in the embodiment and Comparative Example 2, the output (rotation speed when the torque is the same) is improved as compared with Comparative Example 1. It is considered that this is because in the embodiment and Comparative Example 2, the degree of decrease in the salient pole ratio when the current is increased is suppressed as compared with 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 in terms of the degree of decrease in the salient pole ratio. Further, as shown in FIG. 9, the output (rotational speed when the torque is the same) is larger in Comparative Example 2.

Further, as shown in FIG. 10, when the torque is greatly changed, the salient pole ratio is larger in Comparative Example 2 between the embodiment and Comparative Example 2. This is a phenomenon that occurs because the smaller the opening angle θs of the teeth T (opposing surface Ta), the more easily the d-axis magnetic saturation proceeds when the q-axis current is large (that is, the d-axis inductance Ld tends to decrease). It is believed that there is.

The effect of this embodiment will be described.
(1) A protrusion 24 projecting outward in the radial direction is provided between each of the magnet magnetic pole portions 23 having different poles on the outer peripheral portion of the rotor core 21. Then, in the present embodiment and Comparative Example 2, when the radial facing relationship between the rotor core 21 and each tooth T at that time while the rotor 14 makes one revolution is seen, it faces the magnet magnetic pole portion 23 and collides with it. The number of teeth T (teeth T of pattern A) that do not face the portion 24 is the number of teeth T (teeth T of pattern C) that face each other at the same time as the pair of magnet magnetic pole portions 23 that are adjacent to each other in the circumferential direction and the protrusion 24 between them. There are more timings than. As a result, it is possible to suppress a decrease in the salient pole ratio (Lq / Ld) when the current is increased (see FIG. 8). As a result, it can contribute to the improvement of the reluctance torque. Further, as a solution to the needs for miniaturization, in a motor equipped with a disturbance injection type sensorless control in which the position sensor is abolished, the configuration of the present embodiment and Comparative Example 2 in which the decrease in the salient pole ratio is suppressed is adopted. , The error of the rotation position of the rotor 14 can be controlled to be small.

(2) In the present embodiment, when the radial facing relationship between the rotor core 21 and each tooth T at that time while the rotor 14 makes one revolution is seen, it faces the magnet magnetic pole portion 23 and faces the protruding portion 24. The number of teeth T (teeth T of pattern A) that do not face each other is the same as the number of teeth T (teeth T of pattern C) that face each other at the same time as a pair of magnet magnetic pole portions 23 adjacent to each other in the circumferential direction and a protrusion 24 between them. There is a timing (two in this embodiment). Therefore, it is possible to more preferably suppress the decrease in the salient pole ratio when the current is increased (see FIG. 8).

(3) In Comparative Example 2, when the radial facing relationship between the rotor core 21 and each tooth T at that time while the rotor 14 makes one revolution is seen, it faces the magnet magnetic pole portion 23 and faces the protruding portion 24. The number of non-opposing teeth T (teeth T of pattern A) is always larger than the number of teeth T (teeth T of pattern C) 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 protrusion 24 between them. many. Therefore, it can contribute to the improvement of the output of the motor 10 (see FIG. 9).

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

(5) In the present embodiment and Comparative Example 2, the opening angles (opening angles θx between the magnetic poles) between the magnet magnetic poles 23 adjacent to each other in the circumferential direction are set to be equal to each other, and the opening angles θx between the magnetic poles and the magnetic poles are set to be equal to each other. The relationship between the opening angle θs of the facing surface Ta of the teeth T is configured to satisfy θx <θs. Therefore, when the rotor 14 is rotating, the facing surface Ta of the teeth T does not face only the protrusion 24. As a result, it is possible to prevent the magnetic flux from the teeth T from flowing only into the protrusion 24, and as a result, it is possible to suppress a decrease in output.

(6) In the present embodiment and Comparative Example 2, the teeth T have a constant width from the outer end portion in the radial direction to the inner end portion in the axial direction (straight shape). That is, the teeth T of the present embodiment and Comparative Example 2 do not have a shape in which the tip of the teeth expands in the circumferential direction (a shape having an extending portion Tx) as in Comparative Example 1. As a result, it is possible to make the tip portion (diameter inner end portion) facing the rotor core 21 of the teeth T so that the magnetically saturated portion is less likely to change, and as a result, the salient pole ratio when the current is increased. Can be more preferably suppressed. Further, when compared with the configuration in which the opening angle θs of the facing surface Ta is the same in the teeth T having the extending portion Tx as in Comparative Example 1, the straight-shaped teeth T as in the above embodiment and Comparative Example 2 Since the width of the radial intermediate portion of the teeth T can be secured, the magnetic saturation itself at the teeth T can be suppressed, which can contribute to the improvement of the output.

This embodiment can be modified and implemented as follows. The present embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
-The rotor 14 of the above embodiment and Comparative Example 2 may be changed to the rotor 30 as shown in FIG. In the configuration shown in the figure, the same components as those in the above embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. In the rotor 14 of the above embodiment and Comparative Example 2, the reluctance portion between the magnet magnetic pole portions 23 and the protrusions 24 adjacent to each other in the circumferential direction is a recess 25 recessed inward in the radial direction, which is shown in FIG. The configuration changes this. More specifically, in the configuration shown in the figure, the radial outer portion 21a of the permanent magnet 22 in the rotor core 21 (each magnet magnetic pole portion 23) and the protruding portions 24 adjacent to each other on both sides in the circumferential direction of the portion 21a are bridged. They are integrally connected via a unit 31. In other words, the bridge portion 31 extends from each protrusion 24 toward the portion 21a of the magnet magnetic pole portions 23 on both sides in the circumferential direction in the circumferential direction, and is connected to the portion 21a of both magnet magnetic pole portions 23. A gap portion 32 in contact with the circumferential side surface of the permanent magnet 22 is provided inside each bridge portion 31 in the radial direction. Each bridge portion 31 is crushed in the axial direction or the radial direction and plastically deformed, so that the magnetic resistance is formed higher than that of other core portions (the portion 21a and the protrusion 24) and functions as a magnetic resistance portion. do. In such a configuration, one end and the other end in the circumferential direction of the outer peripheral surface of the magnet magnetic pole portion 23 (site 21a) that defines the opening angle θr of the magnet magnetic pole portion 23 are formed by the magnet magnetic pole portion 23 (site 21a) and the magnetoresistive portion. It is desirable to set it at the boundary with a certain bridge portion 31.

-In the above-described embodiment and Comparative Example 2, the parts 21b (the parts between the permanent magnet 22 and the recess 25) on both sides of the permanent magnet 22 in the rotor core 21 are crushed in the axial direction or the radial direction (plastic deformation). ) May be applied to increase the magnetic resistance of the portion 21b.

-In the above-described embodiment and Comparative Example 2, each tooth T has a straight shape (a shape having a constant width from the outer end portion to the inner end portion in the radial direction), but the present invention is not limited to this, and the facing surface Ta is opened. The extension portion Tx as in Comparative Example 1 may be provided without changing the angle θs.

The stator core 15 is divided by the same number as the number of teeth T (a configuration composed of each divided core 15a), but the present invention is not limited to this, and the stator core 15 is integrally formed including the annular portion R and each tooth T. May be good.

The number of poles of the rotor 14 (the number of magnet magnetic poles 23) and the number of slots of the stator 12 (the number of teeth T) in the above embodiment and Comparative Example 2 are examples, and can be appropriately changed to 14 poles: 12 slots and the like. be.

The technical idea is described below.
In an embedded magnet type motor as in Patent Document 1, the larger the salient pole ratio (Lq / Ld), which is the ratio of the q-axis inductance Lq and the d-axis inductance Ld, the larger the reluctance torque can be. .. However, in the embedded magnet type motor, for example, when the current is increased, the q-axis inductance Lq tends to be saturated, which causes a problem that the salient pole ratio is lowered.

The following technical idea was made to solve the above-mentioned problems, and the purpose thereof is to provide a motor capable of suppressing a decrease in the salient pole ratio.
A motor that solves the above problems has a rotating shaft and a rotor core that is coaxially fixed to the rotating shaft, and has a plurality of magnet magnetic pole portions in which permanent magnets are embedded in the rotor core along the circumferential direction. A rotor having a different electrode alternately, a plurality of teeth provided along the circumferential direction and facing the outer peripheral surface of the rotor core in the radial direction, and a stator having windings wound around the teeth are provided. A protrusion protruding outward in the radial direction is provided between each of the magnet magnetic pole portions having different poles on the outer peripheral portion of the rotor core, and the rotor core and the rotor core at each time of the rotation of the rotor are provided. When looking at the radial facing relationship with each tooth, the number of teeth facing the magnet magnetic pole portion and not facing the protrusion portion is the number of the pair of magnet magnetic pole portions adjacent to each other in the circumferential direction and the protrusion between them. It is configured so that there is a timing that is greater than the number of teeth facing each other at the same time as the part.

According to the above aspect, when looking at the radial facing relationship between the rotor core and each tooth while the rotor makes one revolution, the number of teeth facing the magnet magnetic pole portion and not facing the protrusion portion is determined. There will be a pair of magnetic poles adjacent to each other in the circumferential direction and a protrusion between them, and at the same time, there will be a timing that is larger than the number of teeth facing each other. As a result, it is possible to suppress a decrease in the salient pole ratio when the current is increased (see FIG. 8).

-In the motor, when the radial facing relationship between the rotor core and each tooth is seen while the rotor makes one revolution, the teeth facing the magnet magnetic pole portion and not facing the protrusion portion. There is a timing at which the number of the magnet magnetic poles adjacent to each other in the circumferential direction and the number of teeth facing each other at the same time as the protrusions between them are the same.

According to the above aspect, the number of teeth facing the magnet magnetic pole portion and not facing the protrusion portion and the number of teeth facing the pair of magnet magnetic pole portions adjacent to each other in the circumferential direction and the protrusion portion between them at the same time are the same. Since there is such a timing, it is possible to more preferably suppress a decrease in the salient pole ratio when the current is increased (see FIG. 8).

-In the motor, when the radial facing relationship between the rotor core and each tooth is seen while the rotor makes one revolution, the teeth facing the magnet magnetic pole portion and not facing the protrusion portion. Is always larger than the number of the pair of magnet magnetic poles adjacent to each other in the circumferential direction and the teeth facing each other at the same time as the protrusions between them.

According to the above aspect, the number of teeth facing the magnetic poles of the magnet and not facing the protrusions is always larger than the number of teeth facing the pair of magnetic poles adjacent to each other in the circumferential direction and the protrusions between them at the same time. Therefore, it can contribute to the improvement of the output of the motor (see FIG. 9).

In the motor, the opening angles θr of the magnetic poles of the magnets are set to be equal to each other, the opening angles θs of the facing surfaces facing the rotor core in the radial direction in each tooth are set to be equal to each other, and the facing surfaces of the teeth are set to be equal to each other. The relationship between the opening angle θs of the above 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 magnetic poles of the magnet and not facing the protrusions is larger than the number of teeth facing the pair of magnetic poles adjacent to each other in the circumferential direction and the protrusions between them at the same time. It can be configured to have timing.

In the motor, the opening angles θx between the magnet magnetic poles adjacent to each other in the circumferential direction are set to be equal to each other, and the relationship between the opening angles θx and the opening angles θs of the facing surfaces of the teeth is θx <. It is configured to satisfy θs.

According to the above aspect, since the opening angle θs of the facing surfaces of the teeth is larger than the opening angle θx between the magnet magnetic pole portions adjacent to each other in the circumferential direction, the teeth do not face only the protrusions. As a result, it is possible to prevent the magnetic flux from the teeth from flowing only into the protrusion, and as a result, it is possible to suppress a decrease in output.

-In the motor, the teeth have a constant width from the outer end portion in the radial direction to the inner end portion in the axial direction.
According to the above aspect, at the end portion (diameter inner end portion) facing the rotor core in the teeth, it is possible to make the configuration in which the magnetically saturated portion is unlikely to change, and as a result, the reduction of the salient pole ratio is more preferable. Can be suppressed.

10 ... motor, 12 ... stator, 13 ... rotating shaft, 14 ... rotor, 15 ... stator core, T ... teeth, Ta ... facing surface, 16 ... winding, 21 ... rotor core, 22 ... permanent magnet, 23 ... magnet magnetic pole part, 24 ... protrusion, 30 ... rotor.

Claims (2)

Rotation axis and
A rotor having a rotor core coaxially fixed to the rotation axis and having 10 pole magnet magnetic poles in which permanent magnets are embedded in the rotor core so as to be alternately different poles along the circumferential direction. ,
Twelve teeth provided along the circumferential direction and facing the outer peripheral surface of the rotor core in the radial direction, and a stator having windings wound by three-phase concentrated winding around each tooth are provided.
A protrusion protruding outward in the radial direction is provided between each of the magnet magnetic pole portions having different poles on the outer peripheral portion of the rotor core.
The opening angles θr of the magnetic poles of the magnets are set to be equal to each other.
The opening angles θs of the facing surfaces facing the rotor core in the radial direction in each of the teeth are set to be equal to each other.
The opening angles θx between the magnetic poles of the magnets adjacent to each other in the circumferential direction are set to be equal to each other.
The relationship between the opening angle θs of the facing surface of the teeth, the opening angle θr of the magnet magnetic pole portion, and the opening angle θx between the magnet magnetic pole portions is configured to satisfy θx <θs <θr. ,motor. Rotation axis and
A rotor having a rotor core coaxially fixed to the rotation axis and having 10 pole magnet magnetic poles in which permanent magnets are embedded in the rotor core so as to be alternately different poles along the circumferential direction. ,
Twelve teeth provided along the circumferential direction and facing the outer peripheral surface of the rotor core in the radial direction, and a stator having windings wound by three-phase concentrated winding around each tooth are provided.
A protrusion protruding outward in the radial direction is provided between each of the magnet magnetic pole portions having different poles on the outer peripheral portion of the rotor core.
When looking at the radial facing relationship between the rotor core and each tooth while the rotor makes one revolution, the number of teeth facing the magnet magnetic pole portion and not facing the protruding portion is the circumference. A motor configured such that there is a timing greater than the number of teeth facing each other at the same time as the pair of magnet magnetic poles adjacent to each other in the direction and the protrusions between them.

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