JP2019176577A - motor - Google Patents

Abstract

To provide a motor that can prevent a reduction in salient pole ratio.SOLUTION: A motor is configured so as to have a facing relationship in a radial direction between a 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 a magnet magnetic pole part 23 and do not face toward a pseudo magnetic pole part 24 is more than the number of teeth T that face the magnet magnetic pole part 23 and the pseudo magnetic pole part 24 adjacent in the circumferential direction at the same time.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a motor provided with a continuous pole type rotor.

  For example, a continuous pole type (half magnet type) rotor disclosed in Patent Document 1 includes a magnet magnetic pole portion in which a permanent magnet is embedded in an outer peripheral portion of a rotor core, and a magnet magnetic pole portion formed of one part of the rotor core. A plurality of pseudo magnetic pole portions provided with a gap therebetween are alternately provided in the circumferential direction. And each magnet magnetic pole part (each permanent magnet) is set to the same polarity, and each pseudo magnetic pole part functions as a magnetic pole having a different polarity from the magnet magnetic pole part by the magnetic flux of the permanent magnet of the magnet magnetic pole part adjacent in the circumferential direction. To do.

JP 2014-131376 A

  In a motor having a rotor as described in Patent Document 1, the reluctance torque can be increased as the salient pole ratio (Lq / Ld), which is the ratio between the q-axis inductance Lq and the d-axis inductance Ld, is larger. However, in the motor, the stator teeth face each other at the same time as the magnet magnetic pole part and the pseudo magnetic pole part, so that a magnetic path that short-circuits the magnet magnetic pole part and the pseudo magnetic pole part is formed, and the q-axis inductance Lq is reduced. As a result, there is a problem that the salient pole ratio decreases.

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

  A motor that solves the above problems includes a rotating shaft, a rotor having a rotor core fixed coaxially to the rotating shaft, a plurality of teeth provided along the circumferential direction, and teeth that are radially opposed to the outer circumferential surface of the rotor core; And a stator having a winding wound around each of the teeth, and the rotor core has a magnet magnetic pole portion in which a permanent magnet is embedded in an outer peripheral portion thereof, and the magnet magnetic pole portion formed of one portion of the rotor core; Are provided with a plurality of pseudo magnetic pole portions provided alternately with each other in the circumferential direction, the magnet magnetic pole portions having the same polarity, and the pseudo magnetic pole portions having different polarities from the magnet magnetic pole portion. And when the rotor core makes one round, when viewed from the radial opposing relationship between the rotor core and each tooth at that time, facing the magnet magnetic pole portion, and Serial number of pseudo magnetic pole portion not facing teeth, many become timing than the number of teeth simultaneously opposed to said magnet pole portions adjacent to each other in the circumferential direction and the pseudo magnetic pole portion is configured to present.

  According to the above aspect, when the radial opposing relationship between the rotor core and each tooth at that time during one round of the rotor is viewed, the number of teeth facing the magnet magnetic pole part and not facing the pseudo magnetic pole part is There is a timing that is greater than the number of teeth facing the magnet magnetic pole portion and the pseudo magnetic pole portion adjacent in the circumferential direction at the same time. Thereby, the fall of a salient pole ratio can be suppressed.

  In the motor, the teeth facing the magnet magnetic pole portion and not facing the pseudo magnetic pole portion when the radial facing relationship between the rotor core and the teeth at that time of the rotor makes one turn Is always larger than the number of teeth facing the magnet magnetic pole part and the pseudo magnetic pole part adjacent in the circumferential direction at the same time.

  According to the above aspect, the number of teeth facing the magnetic pole part and not facing the pseudo magnetic pole part is always larger than the number of teeth facing the magnet magnetic pole part and the pseudo magnetic pole part adjacent in the circumferential direction at the same time. Further, it is possible to more suitably suppress a decrease in salient pole ratio.

  In the motor, the opening angles θr of the magnet magnetic pole portions are set to be equal to each other, the opening angles θd of the pseudo magnetic pole portions are set to be equal to each other, and the opening of the facing surfaces of the teeth facing the rotor core in the radial direction is opened. The angles θs are set to be equal to each other, and the relationship between the open angles θr, θd, and θs satisfies θs <θd <θr.

  According to the above aspect, the timing at which the number of teeth facing the magnetic pole part and not facing the pseudo magnetic pole part is larger than the number of teeth facing the magnet magnetic pole part and the pseudo magnetic pole part adjacent in the circumferential direction at the same time. Can be configured to exist.

In the motor, the teeth have a constant width from an outer end in the radial direction to an inner end in the axial direction.
According to the above aspect, magnetic saturation in the teeth can be suppressed, which can contribute to securing the motor output.

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

(A) Sectional drawing of the motor of embodiment, (b) The top view which partially enlarges and shows the rotor of the same form. The table which shows the opposing relationship of the rotor core and each tooth for every rotation angle of the rotor in the same form. Sectional drawing of the motor of a comparative example. The graph which shows the salient pole ratio change according to the electric current change in embodiment and a comparative example. The graph which shows the output change according to the torque change in embodiment and a comparative example.

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

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

  Each tooth T has a straight shape having a constant width from the base end portion (outer end portion) in the radial direction to the tip end portion (inner end portion) when viewed in the axial direction. Specifically, as shown in FIG. 1B, the tooth T has a width dimension W perpendicular to the circumferential center line C1 (a straight line perpendicular to the axis L of the rotating shaft 13 and passing through the circumferential center of the tooth T). It is constant over the radial direction. That is, the tooth T of the present embodiment has a configuration that does not include, for example, an extending portion (see, for example, the extending portion Tx illustrated in FIG. 3) that extends from the radially inner end of the tooth T to both sides in the circumferential direction. Yes. In addition, the radially inner side surface (tip surface in the extending direction) of each tooth T is a facing surface Ta that faces the outer peripheral surface of the rotor 14 in the radial direction. The facing surface Ta of each tooth T is an arc surface obtained by extending a concentric arc centering on the axis L of the rotating shaft 13 in the axial direction.

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

  As shown in FIGS. 1 (a) and 1 (b), the rotor 14 disposed inside the stator 12 includes a substantially cylindrical rotor core 21 that is coaxially fixed to the rotating shaft 13. The rotor core 21 is configured by laminating a plurality of core sheets made of, for example, electromagnetic steel plates in the axial direction.

  The rotor core 21 includes a magnet magnetic pole portion 23 in which the permanent magnet 22 is embedded and a pseudo magnetic pole portion 24 formed with a gap K between the magnet magnetic pole portion 23 and a portion of the rotor core 21 at the outer periphery thereof. Provided alternately in the circumferential direction. In the present embodiment, five magnet magnetic pole portions 23 and five pseudo magnetic pole portions 24 are provided. That is, the number of poles of the rotor 14 (number of magnet magnetic pole portions 23) is 10.

  Each magnet magnetic pole portion 23 is formed by embedding a permanent magnet 22 in a portion (a portion between the gaps K) protruding outward in the radial direction in the rotor core 21. The shape of each magnet magnetic pole portion 23 (the shape of the permanent magnet 22 and the shape of the portion of the rotor core 21 in the vicinity where the permanent magnet 22 is embedded) has the same shape. That is, the later-described open angles θr of the magnet magnetic pole portions 23 are equal to each other. In each magnet magnetic pole portion 23, the magnetic pole center lines L1 in the circumferential direction are set at equal intervals in the circumferential direction (72-degree intervals).

  The permanent magnet 22 of each magnet magnetic pole portion 23 has a substantially rectangular parallelepiped shape, and the widest surface thereof is provided so as to be orthogonal to the radial direction of the rotor 14. Each permanent magnet 22 is configured such that the radially outer magnetic pole surfaces have the same polarity (for example, N pole). Thereby, each magnet magnetic pole part 23 is comprised as mutually the same pole (for example, N pole). Each permanent magnet 22 is made of, for example, a sintered magnet or a bonded magnet (such as a plastic magnet or a rubber magnet) that is molded and solidified by mixing magnet powder with resin.

  The pseudo magnetic pole portion 24 formed between the magnet magnetic pole portions 23 in the circumferential direction is formed of a portion that protrudes radially outward from the rotor core 21. Concave portions 25 that are recessed radially inward are formed between the pseudo magnetic pole portion 24 and the magnet magnetic pole portions 23 adjacent to each other in the circumferential direction. That is, the pseudo magnetic pole part 24 and the magnet magnetic pole part 23 are adjacent to each other via the gap K in the recess 25 in the circumferential direction. The pseudo magnetic pole portions 24 have the same shape as each other and are provided at equal intervals in the circumferential direction (72 ° intervals).

  Each pseudo magnetic pole portion 24 functions as a magnetic pole (for example, S pole) having a different polarity from the magnet magnetic pole portion 23 by the magnetic flux of the magnet magnetic pole portion 23 adjacent in the circumferential direction (the magnetic flux of the permanent magnet 22). The magnetic pole center line L1 of the magnet magnetic pole part 23 and the magnetic pole center line L2 of the pseudo magnetic pole part 24 are alternately provided at equal intervals in the circumferential direction (36 degree intervals).

Next, the dimension setting (open angle) in the circumferential direction in each of the magnet magnetic pole part 23, the pseudo magnetic pole part 24, and the teeth T will be described.
As shown in FIG. 1B, the opening angle θr of the magnet magnetic pole portion 23 is an angular width between one end and the other end of the outer peripheral surface of the magnet magnetic pole portion 23 with the axis L as the center. The opening angle θd of the pseudo magnetic pole portion 24 is an angular width between one end and the other end of the outer peripheral surface of the pseudo magnetic pole portion 24 around the axis L. Further, the open angle θs of the teeth T is an angular width between one end and the other end in the circumferential direction of the facing surface Ta with the axis L as the center. The relationship between the open angles θr, θd, and θs is configured to satisfy θs <θd <θr. In addition, the circumferential direction one end and the other end of the outer peripheral surface of the magnet magnetic pole part 23 that define the open angle θr are set as a boundary part with the magnetoresistive part adjacent to the circumferential direction (in this embodiment, the gap K of the recess 25). It is desirable. Similarly, one end and the other end in the circumferential direction of the outer peripheral surface of the pseudo magnetic pole portion 24 that define the open angle θd are set as boundaries with the magnetoresistive portion adjacent in the circumferential direction (the gap K of the recess 25 in this embodiment). It is desirable that

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

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

  FIG. 1A shows the motor 10 when the rotation angle (electrical angle) of the rotor 14 is 6 degrees. At this time, the tooth T having the number “1” is opposed to the magnet magnetic pole portion 23 in front of the center (the centers in the circumferential direction of the teeth T and the magnet magnetic pole portion 23 coincide). Further, the tooth T having the number “7” is opposed to the pseudo magnetic pole portion 24 in front of the teeth T (the centers in the circumferential direction of the teeth T and the pseudo magnetic pole portion 24 coincide). The opposing relationship between the teeth T and the rotor core 21 at this time will be described with reference to the patterns A to C. The teeth T with numbers “1”, “3”, “6”, “8”, and “11” are patterns. A, teeth T with numbers “2”, “5”, “7”, “12” become pattern B, and teeth T with numbers “4”, “9”, “10” become pattern C. That is, the number of teeth in each of the patterns A to C has a relationship of “5” − “4” − “3”. The number of teeth of each of the patterns A to C is always the same as the rotor 14 rotates one round (360 degrees) in electrical angle. In addition, since the rotor 14 of this embodiment is comprised by 10 poles, it will be 1 mechanical angle of the rotor 14 for 5 electrical angles (1800 degrees).

  FIG. 3 shows, as a comparative example, a configuration in which the opening angle θs of the facing surface Ta of the tooth T is larger than that of the present embodiment. The rotor 14 in the comparative example is the same rotor 14 as in this embodiment. In the configuration of the comparative example, the relationship among the opening angle θr of the magnet magnetic pole portion 23, the opening angle θd of the pseudo magnetic pole portion 24, and the opening angle θs of the teeth T is θd <θs <θr. Each tooth T of the same comparative example has an extending portion Tx extending from the radially inner end to both sides in the circumferential direction, thereby ensuring a wide facing surface Ta (opening angle θs) with the rotor core 21. Has been.

  In the state shown in FIG. 3, the opposing relationship of each tooth T with the rotor core 21 will be described with reference to each pattern A to C. Three teeth T of numbers “1”, “6”, and “8” become the pattern A, One tooth T with the number “7” becomes the pattern B, and eight pieces with the numbers “2”, “3”, “4”, “5”, “9”, “10”, “11”, “12” Teeth T are pattern C. The number of teeth “3”-“1”-“8” of the patterns A to C is always the same as the rotor 14 rotates once.

The operation of this embodiment will be described.
The teeth T (pattern C) facing simultaneously with the magnet magnetic pole portion 23 and the pseudo magnetic pole portion 24 form a magnetic path that short-circuits the magnet magnetic pole portion 23 and the pseudo magnetic pole portion 24, and therefore, the comparative example having a large number of teeth of the pattern C Then, the q-axis inductance Lq tends to decrease when the d-axis current is input. On the other hand, in the present embodiment, since the number of teeth of the pattern C is reduced and the number of teeth of the pattern A is increased, it is possible to suppress a decrease in the q-axis inductance Lq when the d-axis current is input. A decrease in salient pole ratio can be suppressed.

  As shown in FIG. 4, when the current supplied to the winding 16 is increased, the degree of decrease in the salient pole ratio (Lq / Ld), which is the ratio between the q-axis inductance Lq and the d-axis inductance Ld, is as follows. The embodiment is fewer than the comparative example.

  Further, as shown in FIG. 5, in this embodiment, the output (the number of revolutions when the torque is the same) is improved as compared with the comparative example. In this embodiment, this is considered to be due to the fact that the degree of decrease in the salient pole ratio when the current value is increased is suppressed as compared with the comparative example.

The effect of this embodiment will be described.
(1) The teeth T facing the magnet magnetic pole portion 23 and not facing the pseudo magnetic pole portion 24 when looking at the radial facing relationship between the rotor core 21 and each tooth T at that time during one round of the rotor 14 There is a timing when the number of (the teeth T of the pattern A) is larger than the number of the teeth T (the teeth T of the pattern C) simultaneously facing the magnet magnetic pole part 23 and the pseudo magnetic pole part 24 adjacent in the circumferential direction. Thereby, the fall of a salient pole ratio (Lq / Ld) can be suppressed (refer FIG. 4). As a result, the reluctance torque can be improved. Further, since leakage of magnetic flux to the pseudo magnetic pole portion 24 can be suppressed when a field weakening current (d-axis current) is input, a suitable high rotation drive can be realized.

  (2) The teeth T facing the magnet magnetic pole portion 23 and not facing the pseudo magnetic pole portion 24 when looking at the radial opposing relationship between the rotor core 21 and each tooth T at that time during one round of the rotor 14 Is always larger than the number of teeth T facing the magnet magnetic pole part 23 and the pseudo magnetic pole part 24 adjacent in the circumferential direction at the same time. For this reason, the fall of a salient pole ratio can be suppressed more suitably.

  (3) The relationship among the opening angle θr of the magnetic pole portion 23, the opening angle θd of the pseudo magnetic pole portion 24, and the opening angle θs of the facing surface Ta of the tooth T is configured to satisfy θs <θd <θr. According to this aspect, the number of teeth T facing the magnet magnetic pole part 23 and not facing the pseudo magnetic pole part 24 is the same as that of the teeth T facing the magnet magnetic pole part 23 and the pseudo magnetic pole part 24 adjacent in the circumferential direction at the same time. It can be configured such that there are more timings than numbers.

  (4) The teeth T have a certain width from the radially outer end to the inner end in the axial direction (straight shape). That is, the teeth T of the present embodiment are not in a shape (a shape having an extension portion Tx) in which the tip of the teeth expands in the circumferential direction as in the comparative example. As a result, it is possible to make a configuration in which the portion where the magnetic saturation occurs is difficult to change at the tip portion (radially inner end portion) of the teeth T facing the rotor core 21, and as a result, the salient pole ratio can be more suitably reduced. It becomes possible to suppress. Moreover, when compared with the configuration in which the opening angle θs of the facing surface Ta is the same in the tooth T having the extension portion Tx as in the comparative example, the diameter of the tooth T in the straight shape tooth T as in the above embodiment. Since the width of the intermediate portion in the direction can be ensured, magnetic saturation itself at the teeth T can be suppressed, and the output can be improved.

This embodiment can be implemented with the following modifications. The present embodiment and the following modifications can be implemented in combination with each other within a technically consistent range.
In the above embodiment, the portions 21a (portions between the permanent magnet 22 and the gap K) on both sides in the circumferential direction of the permanent magnet 22 in the rotor core 21 are crushed (plastically deformed) in the axial direction or the radial direction, for example. Thus, the magnetic resistance of the portion 21a may be increased.

  In the above embodiment, each tooth T has a straight shape (a shape having a constant width from the outer end in the radial direction to the inner end). However, the present invention is not limited to this, and the opening angle θs of the facing surface Ta is changed. Instead, an extension portion Tx as in the comparative example may be provided.

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

  In the above embodiment, the number of teeth of each of the patterns A to C when the rotor 14 is rotated is configured to be “5” − “4” − “3”. The number of teeth of .about.C may be, for example, “4”-“5”-“3”.

  In the above embodiment, the number of poles of the rotor 14 (number of magnet magnetic pole portions 23) and the number of slots of the stator 12 (number of teeth T) are examples, and can be appropriately changed to 14 poles: 12 slots.

The technical idea that can be grasped from the embodiment and the modified examples will be described.
(B) When the opposing relationship in the radial direction between the rotor core and each tooth at that time during one round of the rotor is viewed, the teeth facing the pseudo magnetic pole portion and not facing the magnet magnetic pole portion The timing is such that the number is greater than the number of teeth facing the magnet magnetic pole part and the pseudo magnetic pole part adjacent in the circumferential direction at the same time. Thereby, the fall of a salient pole ratio can be suppressed more suitably.

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

Claims (4)

A rotation axis;
A rotor having a rotor core fixed coaxially to the rotation axis;
A plurality of teeth provided along the circumferential direction and facing the outer circumferential surface of the rotor core in the radial direction, and a stator having a winding wound around each of the teeth,
In the outer periphery of the rotor core, a magnet magnetic pole portion in which a permanent magnet is embedded and a pseudo magnetic pole portion which is a part of the rotor core and is provided with a gap between the magnet magnetic pole portion are alternately arranged in the circumferential direction. Each has multiple,
The magnet magnetic pole portions are the same polarity as each other, and each pseudo magnetic pole portion functions as a magnetic pole having a different polarity from the magnet magnetic pole portion,
The number of teeth facing the magnet magnetic pole part and not facing the pseudo magnetic pole part when looking at the radial facing relationship between the rotor core and each tooth at that time during the round of the rotor, A motor configured to have a timing that is greater than the number of teeth that simultaneously face the magnet magnetic pole portion and the pseudo magnetic pole portion adjacent in the circumferential direction.   The number of teeth facing the magnet magnetic pole part and not facing the pseudo magnetic pole part when looking at the radial facing relationship between the rotor core and each tooth at that time during the round of the rotor, 2. The motor according to claim 1, wherein the motor is always larger than the number of teeth facing the magnet magnetic pole part and the pseudo magnetic pole part adjacent in the circumferential direction at the same time. The opening angles θr of the magnet magnetic pole portions are set equal to each other,
The open angles θd of the pseudo magnetic pole portions are set to be equal to each other,
The opening angles θs of the opposing surfaces in the teeth facing the rotor core in the radial direction are set to be equal to each other,
3. The motor according to claim 1, wherein the relationship between the open angles θr, θd, and θs is configured to satisfy θs <θd <θr.   The motor according to any one of claims 1 to 3, wherein the teeth have a constant width from an outer end in a radial direction to an inner end in an axial view.