Motor

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

Technical Field

[0001] The present invention relates to an embedded magnet type motor.

Background Art

[0002] For example, the motor of Patent Document 1 is an embedded magnet type motor (so-called IPM type motor) in which the magnetic pole portions of the rotor are formed by permanent magnets embedded in the rotor core. Further, the motor of Patent Document 1 is a full magnet type motor in which the permanent magnets forming the respective magnetic pole portions of the rotor are arranged so as to have different polarities alternately in the circumferential direction.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to provide a motor having a rotating shaft and a rotor core fixed coaxially with the rotating shaft, the rotor having ten permanent magnets embedded in the rotor core in the circumferential direction, twelve teeth provided along the circumferential direction and facing the rotor in the radial direction, and a stator having windings wound around each of the teeth in a three-phase concentrated winding, wherein the rotor core is provided with a magnetic resistance portion between the adjacent permanent magnets in the circumferential direction, and when looking at the radial facing relationship between the rotor and the teeth during one rotation of the rotor, the number of teeth facing a pair of adjacent permanent magnets in the circumferential direction and facing the magnetic resistance portion is at most two.

Means for Solving the Problems

[0005] The motor for solving the above problems has a rotating shaft and a rotor core fixed coaxially with the rotating shaft, and 10 permanent magnets are embedded in the rotor core in the circumferential direction. The motor also includes a stator having 12 teeth provided along the circumferential direction and facing the rotor in the radial direction, and windings wound around each tooth in a concentrated winding of three phases. The rotor core is provided with a magnetic resistance portion between the adjacent permanent magnets in the circumferential direction. When looking at the radial facing relationship between the rotor and the teeth during one rotation of the rotor, the number of teeth facing a pair of adjacent permanent magnets in the circumferential direction and facing the magnetic resistance portion is at most 2.

Brief Description of the Drawings

[0006]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Embodiment for Carrying Out the Invention

[0007] Hereinafter, an embodiment of the motor will be described. The motor 10 of the present embodiment shown in Fig. 1(a) is an embedded magnet type (IPM type) brushless motor. The motor 10 includes an annular stator 12 fixed to the inner peripheral surface of a motor housing 11, a rotating shaft 13 arranged coaxially with the stator 12, and a rotor 14 provided on the rotating shaft 13 so as to be integrally rotatable and arranged radially inside the stator 12. The rotating shaft 13 is rotatably supported with respect to the motor housing 11 via a bearing (not shown).

[0008] 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, electromagnetic 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 (i.e., the number of slots) in the present embodiment is 12, and they have the same shape as each other. That is, the opening angles θs described later at the tip portions (radially inner end portions) of the respective teeth T are equal to each other. Also, the respective teeth T are provided at equal intervals (30-degree intervals in the present embodiment) in the circumferential direction. The stator core 15 of the present embodiment is composed of 12 divided cores 15a divided for each tooth T. Each divided core 15a is configured to have one tooth T and a part of the annular portion R.

[0009] Each tooth T has a straight shape with a constant width from the radially-based end (outer end) to the tip end (inner end) in the axial view. Specifically, as shown in Fig. 1(b), the tooth T has a width dimension W perpendicular to its 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) that is constant in the radial direction. That is, the tooth T of the present embodiment is configured not to have an extending portion (for example, refer to the extending portion Tx shown in Fig. 4) that extends from the radially inner end of the tooth T to both sides in the circumferential direction. Further, the radially inner surface (the 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 formed by extending an arc of a concentric circle centered on the axis L of the rotating shaft 13 in the axial direction.

[0010] A three-phase winding 16 is wound around each tooth T by concentrated winding. Then, a three-phase power supply voltage is applied to the winding 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.

[0011] As shown in Figs. 1(a) and 1(b), the rotor 14 disposed inside the stator 12 includes a columnar (circular cross-section) rotor core 21 fixed coaxially with respect to the rotating shaft 13, and a plurality of permanent magnets 22 embedded inside the rotor core 21. The rotor core 21 is configured by laminating a plurality of core sheets made of, for example, electromagnetic steel sheets in the axial direction.

[0012] In the rotor 14 of the present embodiment, ten permanent magnets 22 having the same shape are used, and each permanent magnet 22 is arranged at equal intervals in the circumferential direction (at intervals of 36 degrees) near the outer peripheral surface of the rotor core 21. And each permanent magnet 22 forms magnet pole portions 23 with 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 pole portions 23) is ten poles. Further, the rotor 14 is a full magnet type rotor provided with a permanent magnet 22 at each of all its poles. Each permanent magnet 22 is made of, for example, a sintered magnet, a bonded magnet (such as a plastic magnet or a rubber magnet) formed by mixing magnet powder with resin and molding 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.

[0013] The shapes of the respective magnet pole portions 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) are the same as each other. That is, the opening angles θr described later of the respective magnet pole portions 23 are equal to each other. Further, for each magnet pole portion 23, the magnetic pole center lines Lp in the circumferential direction are set at equal intervals in the circumferential direction (at intervals of 36 degrees).

[0014] The rotor core 21 has protrusions 24 protruding radially outward between the magnet pole portions 23 of different poles from each other on its outer peripheral portion, and a pair of recesses 25 recessed radially inward provided between the protrusions 24 and the magnet pole portions 23 on both sides thereof, respectively. That is, each magnet 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 (at intervals of 36 degrees). The protrusion 24 and the recesses 25 on both sides thereof are formed to be symmetric about the circumferential center of the protrusion 24 (symmetric in the circumferential direction).

[0015] Next, the setting of the circumferential dimensions at each of the magnet pole portion 23, the protrusion 24, the recess 25, and the tip (radially inner end) of the tooth T will be described with reference to FIG. 1(b). The opening angle of the tip of the tooth T (the angular width between one circumferential end and the other end of the opposing surface Ta centered on the axis L) is defined as "θs", and the opening angle of the magnet pole portion 23 (the angular width between one circumferential end and the other end of the outer circumferential surface of the magnet pole portion 23 centered on the axis L) is defined as "θr", and θs < θr is set. Note that it is desirable that one circumferential end and the other end of the outer circumferential surface of the magnet pole portion 23 that define the opening angle θr be set at the boundary with the magnetoresistive portion (the gap of the recess 25 in this embodiment) adjacent in the circumferential direction.

[0016] Also, the opening angle (inter-pole opening angle θx) between the magnet pole portions 23 adjacent in the circumferential direction (the magnet pole portions 23 of opposite polarities to each other) is such that the opening angle of the protrusion 24 (the angular width of the radially outer end of the protrusion 24 centered on the axis L) is defined as "θt", and the opening angle of one recess 25 (the angular width of the radially outer end of the recess 25 centered on the axis L) is defined as "θg", and θx = θt + (θg × 2). And this inter-pole opening angle θx is set to be smaller than the opening angle θs at the tip of the tooth T. That is, in this embodiment, it is set such that θx < θs < θr.

[0017] FIG. 2 is a table showing the radial facing relationship between the rotor core 21 and each tooth T (opposing surface Ta) at each moment when the rotor 14 is rotated in one circumferential direction (counterclockwise direction in FIG. 1(a)) in the motor 10 of this embodiment. Note that, in order to specifically describe each tooth T individually, as shown in FIG. 1(a), each tooth T is sequentially assigned tooth numbers "1" to "12" in the counterclockwise direction in the circumferential direction, and the same tooth numbers correspond to the tooth numbers in the table of FIG. 2.

[0018] In the table of FIG. 2, at each position when the rotor 14 is rotated counterclockwise by 6 electrical degrees (1.2 mechanical degrees) at a time, it shows which pattern among "A", "B", and "C" each tooth T numbered from "1" to "12" is in, and also shows the number of teeth of each pattern A - C for each position (each rotation angle). Pattern A is a pattern where the opposing surface Ta of the tooth T faces the magnet pole portion 23 and does not face the protrusion 24. Pattern B is a pattern where the opposing surface Ta of the tooth T faces one magnet pole portion 23 and the protrusion 24 simultaneously. And pattern C is a pattern where the opposing surface Ta of the tooth T faces a pair of magnet pole portions 23 adjacent in the circumferential direction (magnet pole portions 23 of different polarities from each other) and the protrusion 24 therebetween simultaneously. Note that pattern B does not include pattern C.

[0019] FIG. 1(a) shows the motor 10 when the rotation angle (electrical angle) of the rotor 14 is 6 degrees. At this time, the teeth T numbered "1" and "7" face the magnet pole portion 23 directly (the circumferential centers of the tooth T and the magnet pole portion 23 coincide). Also, the teeth T numbered "4" and "10" face the protrusion 24 directly (the circumferential centers of the tooth T and the protrusion 24 coincide). Now, regarding the facing relationship between each tooth T and the rotor core 21 at this time, explained in each pattern A - C, the teeth T numbered "1" and "7" are in pattern A, the teeth T numbered "2", "3", "5", "6", "8", "9", "11", "12" are in pattern B, and the teeth T numbered "4" and "10" are in pattern C. That is, the number of teeth of each pattern A - C is in the relationship of "2" - "8" - "2".

[0020] When the rotor 14 is rotated counterclockwise from this state, there is a timing when the number of teeth T of 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, four teeth T numbered "1", "6", "7", and "12" become pattern A, six teeth T numbered "2", "3", "5", "8", "9", and "11" become pattern B, and two teeth T numbered "4" and "10" become pattern C. That is, two teeth T numbered "6" and "12" change from pattern C to pattern A, and the number of teeth T in pattern A increases. After the number of teeth of each of patterns A to C becomes in the relationship of "4"-"6"-"2" at this rotation angle (18 degrees), this relationship remains the same until the rotation angle reaches 30 degrees.

[0021] As described above, when the rotation angle of the rotor 14 is 6 degrees and 12 degrees, the number of teeth of each of patterns A to C is "2"-"8"-"2", and then when the rotation angle is 18 degrees, 24 degrees, and 30 degrees, the number of teeth of each of patterns A to C is "4"-"6"-"2". The change in the number of teeth of each of patterns A to C has periodicity every 30 degrees in electrical angle, and each 30-degree cycle is repeated for one turn (360 degrees) in electrical angle. Since the rotor 14 of the present embodiment is composed of 10 poles, one turn of the mechanical angle of the rotor 14 is achieved in five turns (1800 degrees) of the electrical angle.

[0022] [Comparative Example 1] FIG. 4 shows Comparative Example 1 in which the opening angle θs of the tip portion (opposing surface Ta) of the tooth T is made larger than that of the present embodiment. The same rotor 14 as that of the present embodiment is used for the rotor 14 in Comparative Example 1. In the configuration of Comparative Example 1, the relationship between the opening angle θs of the tooth T and the magnet pole portion 23 of the rotor 14 is θr < θs. Each tooth T in Comparative Example 1 has an extension portion Tx that extends from the radially inner end portion to both sides in the circumferential direction, whereby a wide opposing surface Ta (opening angle θs) with the rotor core 21 is ensured.

[0023] FIG. 5 is a table showing the facing relationship of each tooth T to the rotor core 21 in Comparative Example 1 (a table summarized in the same manner as FIG. 2). Also in Comparative Example 1, the change in the number of teeth of each pattern A to C has periodicity every 30 degrees in electrical angle. Although the number of teeth of patterns B and C are in the cases of "8" - [2] and "6" - [4], the number of teeth of 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 when the number of teeth of pattern A becomes more than the number of teeth of pattern C.

[0024] [Comparative Example 2] FIG. 6 shows Comparative Example 2 with a configuration in which the opening angle θs of the tip portion (opposing surface Ta) of the tooth T is made smaller than the configuration of FIG. 1(a). The rotor 14 in Comparative Example 2 uses the same rotor 14 as in the present embodiment. Also in the configuration of Comparative Example 2, the relationship between the opening angle θs of the tooth T and the opening angle θx between the magnetic pole portions of the rotor 14 is θx < θs. Also, the tooth T in Comparative Example 2 has a straight shape with a constant width over the entire radial direction, similar to the tooth T in the above-described embodiment (the configuration of FIG. 1(a)).

[0025] FIG. 7 is a table showing the facing relationship of each tooth T to the rotor core 21 in Comparative Example 2 (a table summarized in the same manner as FIG. 2). Also in Comparative Example 2, the change in the number of teeth of each pattern A to C has periodicity every 30 degrees in electrical angle. Although the number of teeth of patterns B and C are in the cases of "6" - [2] and "8" - [0], the number of teeth of pattern A is always 4 while the rotor 14 rotates 360 degrees in electrical angle. That is, in Comparative Example 2, while the rotor 14 rotates 360 degrees in electrical angle (that is, while the rotor 14 makes one revolution in mechanical angle), the number of teeth of pattern A is always more than the number of teeth of pattern C.

[0026] The operation of the present embodiment will be described. As shown in Fig. 8, when the current supplied to the winding 16 is increased, in the embodiment (the configuration of Fig. 1(a)) and Comparative Example 2, the degree of decrease in the saliency ratio (Lq / Ld), which is the ratio of the q-axis inductance Lq to the d-axis inductance Ld, is smaller than that in Comparative Example 1. In the embodiment and Comparative Example 2, since the number of teeth T of Pattern A (the teeth T facing the magnet pole portion 23 and not facing the protrusion 24) is larger than that in Comparative Example 1, the amount of magnetic flux flowing into the protrusion 24 (q-axis) when the d-axis current is input can be reduced. As a result, the decrease in the q-axis inductance Lq due to magnetic saturation of the protrusion 24 when the current is increased can be suppressed, so it is considered that the degree of decrease in the saliency ratio when the current is increased is smaller in the embodiment and Comparative Example 2 than in Comparative Example 1. Also, in the embodiment and Comparative Example 2, since it is difficult to form a magnetic circuit straddling the d-axis and the q-axis, magnetic interference between the d-axis and the q-axis is less likely to occur. As a result, the difference between the q-axis inductance Lq and the d-axis inductance Ld can be more suitably ensured, and the decrease in the saliency ratio can be more suitably suppressed.

[0027] Also, as shown in Fig. 9, in the embodiment and Comparative Example 2, the output (the rotation speed when the torque is the same) is improved compared to Comparative Example 1. This is presumably because in the embodiment and Comparative Example 2, the degree of decrease in the saliency ratio when the current is increased is suppressed compared to Comparative Example 1.

[0028] In the comparison between the configuration of the embodiment and Comparative Example 2, as shown in Fig. 8, regarding the degree of decrease in the saliency ratio, the configuration of the embodiment is smaller. Also, as shown in Fig. 9, regarding the output (the rotation speed when the torque is the same), Comparative Example 2 is larger.

[0029] Also, as shown in Fig. 10, when the torque is greatly changed, in the embodiment and Comparative Example 2, the saliency ratio of Comparative Example 2 becomes larger. This is presumably a phenomenon caused by the fact that the smaller the opening angle θs of the teeth T (opposing surface Ta), the easier the magnetic saturation of the d-axis progresses when the q-axis current is large (that is, the easier the d-axis inductance Ld decreases).

[0030] The effects of this embodiment will be described. (1) Protrusions 24 protruding radially outward are provided between magnet pole portions 23 of different polarities from each other on the outer peripheral portion of the rotor core 21. In this embodiment and Comparative Example 2, when looking at the radial facing relationship between the rotor core 21 and each tooth T at each time while the rotor 14 makes one revolution, there is a timing when the number of teeth T (teeth T of pattern A) that face the magnet pole portion 23 and do not face the protrusion 24 is larger than the number of teeth T (teeth T of pattern C) that simultaneously face a pair of adjacent magnet pole portions 23 in the circumferential direction and the protrusion 24 therebetween. Thereby, a decrease in the saliency ratio (Lq / Ld) when the current is increased can be suppressed (see FIG. 8). As a result, it is possible to contribute to an improvement in reluctance torque. Further, in a motor equipped with sensorless control of the disturbance injection method in which a position sensor is abolished as a solution to the need for miniaturization, by adopting the configurations of this embodiment and Comparative Example 2 in which a decrease in the saliency ratio is suppressed, the error in the rotational position of the rotor 14 can be controlled with less error.

[0031] (2) In this embodiment, when looking at the radial facing relationship between the rotor core 21 and each tooth T at each time while the rotor 14 makes one revolution, there is a timing when the number of teeth T (teeth T of pattern A) that face the magnet pole portion 23 and do not face the protrusion 24 is the same (two in this embodiment) as the number of teeth T (teeth T of pattern C) that simultaneously face a pair of adjacent magnet pole portions 23 in the circumferential direction and the protrusion 24 therebetween. For this reason, a decrease in the saliency ratio when the current is increased can be more preferably suppressed (see FIG. 8).

[0032] (3) In Comparative Example 2, when looking at the radial facing relationship between the rotor core 21 and each tooth T at each time while the rotor 14 makes one revolution, the number of teeth T (teeth T of pattern A) that face the magnet pole portion 23 and do not face the protrusion 24 is always larger than the number of teeth T (teeth T of pattern C) that simultaneously face a pair of adjacent magnet pole portions 23 in the circumferential direction and the protrusion 24 therebetween. For this reason, it is possible to contribute to an improvement in the output of the motor 10 (see FIG. 9).

[0033] (4) In the present embodiment and Comparative Example 2, the relationship between the opening angle θs of the opposing surface Ta (radial inner surface) that faces the rotor core 21 in each tooth T in the radial direction and the opening angle θr of each magnet pole portion 23 is configured to satisfy θs < θr. According to the above aspect, the number of teeth T (teeth T of pattern A) that face the magnet pole portion 23 and do not face the protrusion 24 can be configured such that there is a timing when it becomes larger than the number of teeth T (teeth T of pattern C) that simultaneously face a pair of adjacent magnet pole portions 23 in the circumferential direction and the protrusion 24 therebetween.

[0034] (5) In the present embodiment and Comparative Example 2, the opening angles (inter-pole opening angle θx) between adjacent magnet pole portions 23 in the circumferential direction are set equal to each other, and the relationship between the inter-pole opening angle θx and the opening angle θs of the opposing surface Ta of the tooth T is configured to satisfy θx < θs. For this reason, when the rotor 14 rotates, the opposing surface Ta of the tooth T does not face only the protrusion 24. Thereby, it is possible to prevent the magnetic flux from the tooth T from flowing only into the protrusion 24, and as a result, it is possible to suppress a decrease in output.

[0035] (6) In the present embodiment and Comparative Example 2, the tooth T has a constant width (straight shape) extending from the outer end portion in the radial direction to the inner end portion in the axial direction view. That is, the teeth T of the present embodiment and Comparative Example 2 do not have a shape in which the tooth tip extends in the circumferential direction (a shape having an extension portion Tx) as in Comparative Example 1. Thereby, it becomes possible to configure a portion where magnetic saturation hardly changes at the tip portion (radial inner end portion) of the tooth T that faces the rotor core 21. As a result, it is possible to more preferably suppress a decrease in the salient pole ratio when the current is increased. Further, when compared with a configuration in which the opening angle θs of the opposing surface Ta is the same in the tooth T having the extension portion Tx as in Comparative Example 1, in the straight-shaped tooth T as in the above embodiment and Comparative Example 2, since the width of the radial intermediate portion of the tooth T can be ensured, magnetic saturation itself in the tooth T can be suppressed, which can contribute to an improvement in output.

[0036] This embodiment can be implemented with the following modifications. This embodiment and the following modification examples can be implemented in combination with each other within a technically non - conflicting range. · The rotor 14 in the above - described embodiment and Comparative Example 2 may be changed to a rotor 30 as shown in FIG. 11. In the configuration of this figure, for the components similar to those in the above - described embodiment, the same reference numerals are given and the detailed description thereof is omitted. In the rotor 14 of the above - described embodiment and Comparative Example 2, the magnetic resistance portion between the magnet pole portion 23 and the protrusion 24 adjacent to each other in the circumferential direction was a recessed portion 25 that was recessed inward in the radial direction, but this is changed in the configuration shown in FIG. 11. Specifically, in the configuration shown in this figure, a portion 21a outside the permanent magnet 22 in the rotor core 21 (each magnet pole portion 23) and the protrusions 24 adjacent to both sides in the circumferential direction of the portion 21a are integrally connected via a bridge portion 31. In other words, the bridge portion 31 extends in the circumferential direction from each protrusion 24 toward the portion 21a of the magnet pole portions 23 on both sides in the circumferential direction and is connected to the portion 21a of both magnet pole portions 23. A gap portion 32 in contact with the circumferential side surface of the permanent magnet 22 is provided inside the bridge portion 31 in the radial direction. Each bridge portion 31 is formed to have a higher magnetic resistance than other core portions (the portion 21a and the protrusion 24), for example, by being crushed in the axial or radial direction and plastically deformed, and functions as a magnetic resistance portion. In such a configuration, it is desirable that one end and the other end in the circumferential direction of the outer peripheral surface of the magnet pole portion 23 (portion 21a) that defines the opening angle θr of the magnet pole portion 23 be set at the boundary between the magnet pole portion 23 (portion 21a) and the bridge portion 31 that is the magnetic resistance portion.

[0037] · In the above - described embodiment and Comparative Example 2, with respect to the portions 21b on both sides in the circumferential direction of the permanent magnet 22 in the rotor core 21 (the portions between the permanent magnet 22 and the recessed portion 25), for example, by applying crushing (plastic deformation) in the axial or radial direction, a configuration may be adopted in which the magnetic resistance of the portion 21b is increased.

[0038] ·In the above-described embodiment and Comparative Example 2, each tooth T was formed in a straight shape (a shape having a constant width from the outer end portion in the radial direction to the inner end portion), but the present invention is not limited thereto, and an extending portion Tx as in Comparative Example 1 may be provided without changing the opening angle θs of the opposing surface Ta.

[0039] ·The stator core 15 was configured to be divided into the same number as the number of teeth T (a configuration composed of each divided core 15a), but the present invention is not limited thereto, and the stator core 15 including the annular portion R and each tooth T may be integrally formed.

[0040] ·The number of poles of the rotor 14 (the number of magnet pole portions 23) and the number of slots of the stator 12 (the number of teeth T) in the above-described embodiment and Comparative Example 2 are merely examples, and can be appropriately changed to, for example, 14 poles: 12 slots.

[0041] The following technical idea will be described. ·In an embedded magnet type motor such as the above-described Patent Document 1, the larger the saliency ratio (Lq / Ld), which is the ratio of the q-axis inductance Lq to the d-axis inductance Ld, the larger the reluctance torque can be. However, in an embedded magnet type motor, for example, when the current is increased, the q-axis inductance Lq is likely to saturate, thereby causing a problem that the saliency ratio decreases.

[0042] The following technical idea has been made to solve the above problems, and an object thereof is to provide a motor capable of suppressing a decrease in the saliency ratio. ·The motor for solving the above problems has a rotating shaft and a rotor core fixed coaxially with the rotating shaft, and a rotor having a plurality of magnet pole portions in which permanent magnets are embedded in the rotor core and having different polarities alternately along the circumferential direction, and a stator having a plurality of teeth provided along the circumferential direction and facing the outer peripheral surface of the rotor core in the radial direction, and windings wound around the respective teeth. Protrusions protruding radially outward are provided between the magnet pole portions of different polarities on the outer peripheral portion of the rotor core. When looking at the radial facing relationship between the rotor core and the respective teeth at each time during one rotation of the rotor, the number of teeth facing the magnet pole portion and not facing the protrusion is configured such that there is a timing when it becomes larger than the number of teeth facing a pair of magnet pole portions adjacent in the circumferential direction and the protrusion therebetween at the same time.

[0043] According to the above aspect, when looking at the radial facing relationship between the rotor core and the respective teeth at each time during one rotation of the rotor, there is a timing when the number of teeth facing the magnet pole portion and not facing the protrusion becomes larger than the number of teeth facing a pair of magnet pole portions adjacent in the circumferential direction and the protrusion therebetween at the same time. Thereby, a decrease in the saliency ratio when the current is increased can be suppressed (see FIG. 8).

[0044] ·In the above motor, when looking at the radial facing relationship between the rotor core and the respective teeth at each time during one rotation of the rotor, there is a timing when the number of teeth facing the magnet pole portion and not facing the protrusion is the same as the number of teeth facing a pair of magnet pole portions adjacent in the circumferential direction and the protrusion therebetween at the same time.

[0045] According to the above aspect, since there is a timing when the number of teeth facing the magnet pole portion and not facing the protrusion is the same as the number of teeth facing a pair of magnet pole portions adjacent in the circumferential direction and the protrusion therebetween at the same time, a decrease in the saliency ratio when the current is increased can be more preferably suppressed (see FIG. 8).

[0046] · In the above motor, when looking at the radial facing relationship between the rotor core and each tooth at each moment during one rotation of the rotor, the number of teeth that face the magnet pole portion and do not face the protrusion is always greater than the number of teeth that simultaneously face a pair of magnet pole portions adjacent to each other in the circumferential direction and the protrusion therebetween.

[0047] According to the above aspect, since the number of teeth that face the magnet pole portion and do not face the protrusion is always greater than the number of teeth that simultaneously face a pair of magnet pole portions adjacent to each other in the circumferential direction and the protrusion therebetween, it can contribute to improving the output of the motor (see Fig. 9).

[0048] · In the above motor, the opening angles θr of the respective magnet pole portions are set to be equal to each other, the opening angles θs of the facing surfaces that face the rotor core in the radial direction in each tooth are set to be equal to each other, and the relationship between the opening angle θs of the facing surface of the tooth and the opening angle θr of the magnet pole portion is configured to satisfy θs < θr.

[0049] According to the above aspect, it is possible to configure such that there is a timing when the number of teeth that face the magnet pole portion and do not face the protrusion becomes greater than the number of teeth that simultaneously face a pair of magnet pole portions adjacent to each other in the circumferential direction and the protrusion therebetween.

[0050] · In the above motor, the opening angles θx between the magnet pole portions adjacent to each other in the circumferential direction are 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 tooth is configured to satisfy θx < θs.

[0051] According to the above aspect, since the opening angle θs of the facing surface of the tooth is larger than the opening angle θx between the magnet pole portions adjacent to each other in the circumferential direction, the tooth does not face only the protrusion. As a result, it is possible to prevent the magnetic flux from the tooth from flowing only into the protrusion, and thus, it is possible to suppress the output reduction.

[0052] ·In the above motor, the teeth have a constant width from the outer end in the radial direction to the inner end in the axial direction view. According to the above aspect, it is possible to form a configuration in which the magnetically saturated portion hardly changes at the end portion (radial inner end portion) of the teeth facing the rotor core, and as a result, it is possible to more preferably suppress a decrease in the salient pole ratio.

[0053] ·The object of the following technical idea is to provide a motor having a rotating shaft and a rotor core fixed coaxially with the rotating shaft, the rotor having a 10-pole magnet pole portion in which permanent magnets are embedded and having different poles alternately along the circumferential direction, a plurality of 12 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 each of the teeth in a three-phase concentrated winding, and a protrusion protruding radially outward is provided between the magnet pole portions of different poles from each other on the outer peripheral portion of the rotor core.

[0054] ·The motor that achieves the above object has a rotating shaft and a rotor core fixed coaxially with the rotating shaft, the rotor having a 10-pole magnet pole portion in which permanent magnets are embedded and having different poles alternately along the circumferential direction, a plurality of 12 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 each of the teeth in a three-phase concentrated winding, and a protrusion protruding radially outward is provided between the magnet pole portions of different poles from each other on the outer peripheral portion of the rotor core, the opening angles θr of the respective magnet pole portions are set to be equal to each other, the opening angles θs of the opposing surfaces of the respective teeth facing the rotor core in the radial direction are set to be equal to each other, the opening angles θx between the circumferentially adjacent magnet pole portions are set to be equal to each other, and the relationship between the opening angle θs of the opposing surface of the teeth, the opening angle θr of the magnet pole portion, and the opening angle θx between the magnet pole portions satisfies θx < θs < θr.

[0055] ·The motor for achieving the above object has a rotating shaft and a rotor core fixed coaxially with the rotating shaft, and the rotor has a 10-pole magnet pole portion in which permanent magnets are embedded and which has north and south poles alternating in a circumferential direction, a stator having a plurality of 12 teeth provided along the circumferential direction and facing the outer peripheral surface of the rotor core in the radial direction, and windings wound around each of the teeth in a concentrated winding manner. Protrusions protruding radially outward are provided between the magnet pole portions of different poles from each other on the outer peripheral portion of the rotor core. When looking at the radial facing relationship between the rotor core and each of the teeth as the rotor makes one revolution, it is configured such that there is a timing at which the number of teeth facing the magnet pole portion and not facing the protrusion is greater than the number of teeth facing a pair of adjacent magnet pole portions in the circumferential direction and the protrusion therebetween at the same time.

[0056] ·The object of the following technical idea is to provide a motor having a rotating shaft, a rotor having a plurality of magnet pole portions in which permanent magnets are embedded and which are fixed coaxially with the rotating shaft and have north and south poles alternating in a circumferential direction, a stator having a plurality of teeth provided along the circumferential direction and facing the outer peripheral surface of the rotor core in the radial direction, and windings wound around each of the teeth in a concentrated winding manner, and "magnetic resistance portions" or "recessed or void portions" are provided on both sides in the circumferential direction of the magnet pole portions.

[0057] ·The motor for achieving the above object has a rotating shaft and a rotor core coaxially fixed to the rotating shaft, and the rotor has a plurality of magnet pole portions in which permanent magnets are embedded, and the magnet pole portions are alternately of different polarities along the circumferential direction. The motor also includes a stator having a plurality of teeth provided along the circumferential direction and radially opposed to the outer peripheral surface of the rotor core, and windings wound around each of the teeth by concentrated winding. Magnetic resistance portions are provided on both circumferential sides of the magnet pole portions. When looking at the radial facing relationship between the rotor core and each of the teeth at each time during one rotation of the rotor, there is a timing such that the number of teeth facing the magnet pole portions and not facing the magnetic resistance portions is greater than the number of teeth facing a pair of adjacent magnet pole portions in the circumferential direction and the magnetic resistance portion therebetween at the same time.

[0058] ·The motor for achieving the above object has a rotating shaft and a rotor core coaxially fixed to the rotating shaft, and the rotor has a plurality of magnet pole portions in which permanent magnets are embedded, and the magnet pole portions are alternately of different polarities along the circumferential direction. The motor also includes a stator having a plurality of teeth provided along the circumferential direction and radially opposed to the outer peripheral surface of the rotor core, and windings wound around each of the teeth by concentrated winding. Recesses or void portions are provided on both circumferential sides of the magnet pole portions. When looking at the radial facing relationship between the rotor core and each of the teeth at each time during one rotation of the rotor, there is a timing such that the number of teeth facing the magnet pole portions and not facing the recesses or void portions is greater than the number of teeth facing a pair of adjacent magnet pole portions in the circumferential direction and the recesses or void portions therebetween at the same time.

[0059] ·In the above motor, the rotor has 10 magnet pole portions, the stator has 12 teeth, and three-phase windings are wound around each of the teeth by concentrated winding. · The object of the following technical idea is to provide a "motor" or a "motor" having "a rotor having a rotating shaft and a rotor core fixed coaxially with the rotating shaft, the rotor having a 10-pole magnet pole portion in which permanent magnets are embedded and having different poles alternately along the circumferential direction, and a stator having 12 teeth provided along the circumferential direction and facing the outer peripheral surface of the rotor core in the radial direction, and windings wound around each of the teeth in a three-phase concentrated winding manner, wherein a magnetic resistance portion is provided between the magnet pole portions of different poles on the outer peripheral portion of the rotor core, the opening angles θr of the respective magnet pole portions are set equal to each other, the opening angles θs of the opposing surfaces of the respective teeth facing the rotor core in the radial direction are set equal to each other, and the opening angles θx between the magnet pole portions adjacent to each other in the circumferential direction are set equal to each other", or "a rotating shaft, a rotor core composed of a plurality of core sheets laminated in the axial direction and fixed coaxially with the rotating shaft, the rotor having a 10-pole magnet pole portion in which a permanent magnet having a substantially rectangular parallelepiped shape and having a wide surface orthogonal to the radial direction is embedded and having different poles alternately along the circumferential direction, a stator core having 12 teeth and an annular portion, the opposing surfaces of which facing the outer peripheral surface of the rotor core are arc surfaces, the stator core being composed of a plurality of core sheets laminated in the axial direction and consisting of 12 divided cores in the circumferential direction, and a stator having windings wound around each of the teeth in a three-phase concentrated winding manner, and a motor housing rotatably supporting the rotating shaft and fixing the stator, wherein a magnetic resistance portion is provided between the magnet pole portions of different poles on the outer peripheral portion of the rotor core, the opening angles θr of the respective magnet pole portions are set equal to each other, the opening angles θs of the opposing surfaces of the respective teeth facing the rotor core in the radial direction are set equal to each other, the opening angles θx between the magnet pole portions adjacent to each other in the circumferential direction are set equal to each other, and the relationship between the opening angle θs of the opposing surface of the tooth, the opening angle θr of the magnet pole portion, and the opening angle θx between the magnet pole portions satisfies θx < θs < θr".

[0060] ·The motor for achieving the above object has a rotating shaft and a rotor core fixed coaxially with the rotating shaft, and the rotor has a 10-pole magnet magnetic pole portion in which permanent magnets are embedded, and the magnet magnetic pole portions are alternately of different polarities along the circumferential direction. The motor further includes a stator having 12 teeth provided along the circumferential direction and facing the outer peripheral surface of the rotor core in the radial direction, and windings wound around each of the teeth in a concentrated winding of three phases. A magnetic resistance portion is provided between the magnet magnetic pole portions of different polarities on the outer peripheral portion of the rotor core. Gap portions functioning as the magnetic resistance portion are provided on both circumferential sides of the magnet magnetic pole portion. The gap portions are in contact with the circumferential side surfaces of the permanent magnets without contacting the side surfaces of the permanent magnets on the radially outer side. The radially inner end of the portion in contact with the circumferential side surface of the permanent magnet in the gap portion is located radially outside the radially inner end of the circumferential side surface of the permanent magnet. The opening angles θr of the respective magnet magnetic pole portions are set to be equal to each other, the opening angles θs of the opposing surfaces of the respective teeth facing the rotor core in the radial direction are set to be equal to each other, and the opening angles θx between the adjacent magnet magnetic pole portions in the circumferential direction are set to be equal to each other.

[0061] · The motor for achieving the above object has a rotating shaft and a rotor core fixed coaxially with the rotating shaft, and the rotor has a 10-pole magnet pole portion in which permanent magnets are embedded, and the magnet pole portions are alternately of different polarities along the circumferential direction. The stator has 12 teeth provided along the circumferential direction and facing the outer peripheral surface of the rotor core in the radial direction, and windings wound around each tooth in a concentrated winding of three phases. A magnetic resistance portion is provided between the magnet pole portions of different polarities on the outer peripheral portion of the rotor core. Recesses that function as the magnetic resistance portion are provided on both circumferential sides of the magnet pole portion. The recesses are recessed radially inward along the circumferential side surface of the permanent magnet of the magnet pole portion. The radially inner end of the recess is located within the radial length range of the permanent magnet of the magnet pole portion and is located radially outside the radially inner end of the permanent magnet. The opening angles θr of the respective magnet pole portions are set to be equal to each other. The opening angles θs of the opposing surfaces of the respective teeth facing the rotor core in the radial direction are set to be equal to each other. The opening angles θx between the adjacent magnet pole portions in the circumferential direction are set to be equal to each other.

[0062] · In the above motor, the relationship among the opening angle θs of the opposing surface of the tooth, the opening angle θr of the magnet pole portion, and the opening angle θx between the magnet pole portions is configured to satisfy θx < θs < θr.

[0063] ·The motor for achieving the above object has a rotor core that is composed of a plurality of core sheets laminated in the axial direction and is coaxially fixed to the rotating shaft, and has a 10-pole magnet magnetic pole portion in which permanent magnets having a substantially rectangular parallelepiped shape and whose wide surfaces are orthogonal to the radial direction are embedded in the rotor core in such a manner that the poles alternate in the circumferential direction; a stator core having 12 teeth and an annular portion whose opposing surfaces facing the outer peripheral surface of the rotor core in the radial direction are arc surfaces, the stator core being composed of a plurality of core sheets laminated in the axial direction and consisting of 12 divided cores in the circumferential direction; a stator having windings wound around each of the teeth in a concentrated winding of three phases; and a motor housing that rotatably supports the rotating shaft and fixes the stator. A magnetic resistance portion is provided between the magnet magnetic pole portions of different poles from each other on the outer peripheral portion of the rotor core. Gap portions that function as the magnetic resistance portion are provided on both sides in the circumferential direction of the magnet magnetic pole portion. The gap portions are in contact with the circumferential side surfaces of the permanent magnets without contacting the side surfaces on the radially outer side of the permanent magnets. The radially inner end of the portion in contact with the circumferential side surface of the permanent magnet in the gap portion is located radially outside the radially inner end of the circumferential side surface of the permanent magnet. The opening angles θr of the respective magnet magnetic pole portions are set to be equal to each other. The opening angles θs of the opposing surfaces of the respective teeth facing the rotor core in the radial direction are set to be equal to each other. 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. The relationship among the opening angle θs of the opposing 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.

[0064] · The motor that achieves the above object has a rotor core composed of a rotating shaft and a plurality of core sheets laminated in the axial direction and fixed coaxially with the rotating shaft, and has a 10-pole magnet magnetic pole portion in which permanent magnets having a substantially rectangular parallelepiped shape and whose wide surfaces are orthogonal to the radial direction are embedded in the rotor core in such a manner that the poles alternate in the circumferential direction, a stator core having 12 teeth and an annular portion whose opposing surface facing the outer peripheral surface of the rotor core in the radial direction is an arc surface, the stator core being composed of a plurality of core sheets laminated in the axial direction and consisting of 12 divided cores in the circumferential direction, a stator having windings wound around each of the teeth in a concentrated winding of three phases, and a motor housing that rotatably supports the rotating shaft and fixes the stator. A magnetic resistance portion is provided between the magnet magnetic pole portions of different poles from each other on the outer peripheral portion of the rotor core. Recesses that function as the magnetic resistance portion are provided on both circumferential sides of the magnet magnetic pole portion. The recesses are recessed radially inward along the circumferential side surface of the permanent magnet of the magnet magnetic pole portion. The radially inner end of the recess is located within the radial length range of the permanent magnet of the magnet magnetic pole portion and is located radially outside the radially inner end of the permanent magnet. The opening angles θr of the respective magnet magnetic pole portions are set to be equal to each other. The opening angles θs of the opposing surfaces of the respective teeth facing the rotor core in the radial direction are set to be equal to each other. 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. The relationship among the opening angle θs of the opposing 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.

Explanation of Reference Numerals

[0065] 10… motor, 12… stator, 13… rotating shaft, 14… rotor, 15… stator core, T… teeth, Ta… opposing surface, 16… winding, 21… rotor core, 22… permanent magnet, 23… magnet magnetic pole portion, 24… protrusion, 30… rotor.

Claims

1. A rotation axis; a rotor having a rotor core fixed coaxially to the rotating shaft, the rotor having ten magnetic poles formed by ten permanent magnets embedded in the rotor core in a circumferential direction; a stator having twelve teeth arranged along a circumferential direction and radially opposed to the rotor, and a winding wound by three-phase concentrated winding around each of the teeth; Equipped with The rotor core has a magnetic resistance portion between the permanent magnets adjacent in the circumferential direction, When the rotor rotates once, the rotor and the teeth are opposed to each other in the radial direction. the number of teeth facing a pair of the permanent magnets adjacent in the circumferential direction and facing the magnetic resistance portion is a maximum of two, A motor configured so that θs<θr is satisfied when the open angle of each of the magnetic pole portions is θr and the open angle of the opposing surface of each of the teeth that radially faces the rotor core is θs.

2. 2. The motor according to claim 1, wherein the number of teeth facing a pair of circumferentially adjacent permanent magnets and facing the magnetic resistance portion is always two.

3. 2. The motor according to claim 1, wherein there are two timings and zero timings for the number of teeth that face a pair of circumferentially adjacent permanent magnets and that face the magnetic resistance portion.

4. The motor according to any one of claims 1 to 3, wherein the magnetic resistance portion is a recess, a gap, or a bridge portion.

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