JP2006204052A - Electric motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric motor that prevents the occurrence of vibration and the like while suppressing the fluctuation of the output, increasing the mechanical strength and preventing the occurrence of damage, even when the output is increased.
A stator 12 of the electric motor includes a substantially cylindrical stator body 31 and a plurality of teeth 33 formed to protrude in a radial direction at predetermined positions in the circumferential direction of the stator body. A tip surface of each tooth facing the rotor 11 faces the stator via a predetermined amount of motor gap GP, and a coil 35 for energization is wound around each tooth to form a salient pole 32. Each tooth stands in the radial direction from the stator main body and is divided into a magnetic pole tooth 41 having a divided structure divided in the circumferential direction through a groove drilled in the radial direction, and is integrally combined with the groove and the tip. A tooth tip portion 42 having a top portion 42A which is fixed to the magnetic pole teeth and provides the tip surface. The circumferential width of the top portion 42 </ b> A is formed wider than the circumferential width of the salient pole magnetic pole 32.
[Selection] Figure 1

Description

  The present invention relates to an electric motor having a stator facing a rotor with a gap of a predetermined dimension, and more particularly to an electric motor having a structure in which a plurality of salient poles provided on the stator are divided.

  In general, in a motor (electric motor) having a stator (stator) facing a rotor (rotor) through a gap of a predetermined dimension, a plurality of teeth are projected from the stator, and a coil is provided for each of the teeth. As a result, a salient pole magnetic pole is formed.

  In a motor having a structure having a salient pole, the number of windings wound around the teeth is increased as much as possible (improvement of the space factor), and the area where the electromagnetic force acts (area receiving the magnetic flux) is increased. For this reason, as shown in Patent Documents 1 to 3, a structure is known in which a tooth tip portion facing a gap or a salient pole magnetic pole portion is divided.

  However, these divided structures can increase the space factor and the area of action of electromagnetic force, but as pointed out in Patent Documents 4 and 5, at the time of manufacturing, It is very difficult to increase the accuracy of mechanical dimensions such as circularity. The mechanical variation of these salient poles leads to an increase in cogging torque, an increase in torque fluctuation, etc., and due to the weak mechanical strength of the divided parts, it causes motor vibration and noise generation, resulting in characteristics It was difficult to provide a good motor.

In order to solve this problem, a structure described in Patent Documents 6 and 7 has been proposed. Specifically, the electric motor described in Patent Document 6 is configured to receive a reaction force of rotational torque by bringing adjacent tooth tips into contact with each other. In the case of the electric motor described in Patent Document 7, the yoke portion of the stator core is divided, and the divided yoke portion core is evenly stressed in the inner diameter direction after assembling so that the accuracy of the core dimensions can be improved. I try to correct it.
JP 2003-52139 A Japanese Patent Laid-Open No. 10-94280 JP 2000-152528 A Japanese Patent Laid-Open No. 2000-190088 JP 2001-218429 A JP 2001-190038 A JP 2001-218429 A

  According to the structure of the electric motor described in Patent Documents 6 and 7, the output fluctuation can be improved by suppressing cogging or the like, but on the other hand, there is a problem that the mechanical strength is inevitably lowered. It was. The problem of a decrease in mechanical strength is not a concern when the output torque of the motor is low, but in the case of a motor with a high output torque, motor vibration and noise are likely to occur.

  The present invention has been made in view of the above-described problems, and provides an electric motor having sufficiently high mechanical strength while suppressing output fluctuations (cogging, torque ripple) even when output is increased. Objective.

  In order to achieve the above-mentioned object, the electric motor of the present invention has, as one basic aspect thereof, a stator that is fixedly arranged, and can be rotated to face this stator via a predetermined amount of gap in the radial direction. And a stator having a substantially cylindrical stator body and a plurality of teeth formed to project from the stator body in the radial direction at predetermined positions in the circumferential direction of the stator body. The front end surface of each tooth facing the rotor faces the stator via the predetermined amount of gap, and a coil for energization is wound around each tooth to form a salient pole. In this configuration, each of the plurality of teeth rises in the radial direction from the stator body and is divided in the circumferential direction through a groove formed in the radial direction, and the magnetic pole teeth A tooth tip portion that is integrally combined with the tooth groove and the tip portion and has a top portion that is fixed to the magnetic pole tooth and provides the tip face. The circumferential width of the top is formed wider than the circumferential width of the magnetic pole.

  According to the electric motor of the present invention, each of the plurality of teeth rises in the radial direction from the stator body and has a divided structure of magnetic pole teeth that are divided in the circumferential direction through a groove formed in the radial direction. A tooth tip portion that is integrally combined with the groove and the tip portion of the magnetic pole tooth and has a top portion that is fixed to the magnetic pole tooth and provides a tip surface for the motor gap, so that the magnetic pole tooth and the tooth tip portion are connected to each other. Only with care, the roundness of the stator can be easily secured and the structure can be strengthened. For this reason, the salient pole magnetic pole structure which can endure high output torque can be provided. In addition, since the circumferential width of the top portion is formed wider than the circumferential width of the salient pole magnetic pole, the area where the electromagnetic force acts (area receiving the magnetic flux) can be increased. As a result, even when the output is increased, it is possible to provide an electric motor that suppresses fluctuations in output (cogging, torque ripple) and increases mechanical strength to prevent vibration and the like.

  Hereinafter, with reference to FIGS. 1-6, one Embodiment of the electric motor (motor) which concerns on this invention is described.

  The electric motor according to the present invention is either an outer rotor type in which the rotor (rotor) is located outside (the stator (stator) is inside) or an inner rotor type in which the rotor is located inside (the stator is outside). However, in this embodiment, an outer rotor type motor will be described. Of course, the electric motor implemented in the present invention can be applied to both direct current and alternating current. Further, in the case of an AC motor, it can be implemented with a single phase or a plurality of phases such as three phases.

  In FIG. 1, sectional drawing for demonstrating the structure of 10 of the electric motor which concerns on this embodiment is shown. Here, for convenience of explanation, an orthogonal coordinate system in which the direction of the rotation axis of the electric motor 10 is the Z axis is set as illustrated. Therefore, the axial direction is the Z-axis direction, the circumferential direction (circumferential direction: see arrow P) is the rotational direction when the Z-axis is the rotational axis, and the radial direction is the Z-axis rotational axis ( This is the radial direction of the motor when the center axis is taken.

  As shown in the figure, the electric motor 10 is disposed so as to oppose a cylindrical rotor 11 (only a part of which is shown in FIG. 1) and a gap GP (motor gap) of a predetermined distance in the radial direction. The stator 12 is provided. In this embodiment, the rotor 11 is an outer rotor type positioned on the outer side of the stator 12 in the radial direction, and is formed as a three-phase AC motor. The rotor 11 and the stator 12 are coaxially arranged in an electric motor cover (not shown).

  The rotor 11 includes a back yoke 21 made of a hollow annular magnetic body, and a plurality of (for example, 22) permanent magnet magnetic poles 22 fixed at predetermined positions on the inner peripheral surface of the back yoke 21. The permanent magnet magnetic pole 22 is magnetized with an even distribution by alternately changing the N pole and the S pole so as to face a salient pole magnetic pole on the stator side described later. In addition to this, as the permanent magnet magnetic pole 22, it is preferable to reduce a sticking error to the back yoke 21 by using a segment magnet having a pair of N pole and S pole or a ring-shaped field permanent magnet.

  On the other hand, the stator 12 has a cylindrical stator body 31 and a plurality of salient poles 32 erected radially outward at predetermined positions over the entire circumference of the stator body 31. .

The plurality of salient poles 32 are all formed in the same shape. As shown in FIG. 1, each of the salient poles 32 is erected from the stator body 31 with its top portion slightly larger than the main body portion in a shade shape. A tooth 33 and a coil 35 wound around the tooth 33 via an insulator 34 are provided.
The stator body 31 and the plurality of teeth 33 are formed by laminating a plurality of punched thin electromagnetic steel sheets or the like (for example, silicon steel sheets in the present embodiment). This stacking direction is the Z-axis direction after the electric motor 10 in FIG. 1 is assembled.

  Each tooth 33 is fixed and attached to the magnetic pole teeth 41 formed with a substantially V-shaped groove 41A at the center in the circumferential direction when viewed from the axial direction (Z-axis direction). And a substantially T-shaped (wedge-shaped) tooth tip portion 42. The tooth tip portion 42 is fixed to the magnetic pole tooth 41 with its wedge-shaped portion mounted in the groove 41 </ b> A of the magnetic pole tooth 41. Since the magnetic pole teeth 41 and the tooth tip portion 42 are members corresponding to the features of the present invention, they will be described in detail below.

  As shown in FIG. 2, the magnetic pole teeth 41 are pillar-shaped members having outer dimensions in the radial direction (Y-axis direction in FIG. 2) formed in the same width W <b> 1 when viewed from the axial direction, and are integrated with the stator body 31. Is formed. A substantially V-shaped (a shape when viewed from the axial direction) groove 41A is provided at the center of the magnetic pole teeth 41 in the circumferential direction (see arrow P). As shown in FIG. 2, the groove 41 </ b> A is formed so as to penetrate the column portion of the magnetic pole tooth 41 in the radial direction from the upper surface to the lower portion, and its bottom portion is the outer surface in the radial direction of the starter body 31. It is lowered to a predetermined position that exceeds the level (see symbol d). Such a stator main body 31 and a plurality of magnetic pole teeth 41 are integrally formed by laminating a predetermined number of silicon steel plates punched into a shape partially shown in FIG.

  As described in detail in FIG. 3, the V-shaped groove 41A is formed such that the width W2 in the circumferential direction becomes narrower as the position becomes lower in the radial direction (the direction toward the stator body). . However, this width W2 is a constant width W3 different from the V-shape at a position where it rises from the predetermined range above the groove 41A to the upper surface of the magnetic pole teeth 41.

  That is, as shown in FIG. 3, a wall surface parallel to a center line C extending in the radial direction passing through the circumferential center position of the magnetic pole teeth 41, that is, the groove 41A (first surface) F1 is formed symmetrically on both sides over a predetermined height range H1. W3 between the first surfaces F1 in the circumferential direction is the same as the maximum value W2max of the width W2 of the groove 41A. That is, the width W2 of the groove 41A gradually increases as it goes upward of the magnetic pole teeth 41, and when it reaches its maximum value W2max (= W3), it is connected to the first surfaces F1 on both sides and remains as it is. Extends to the top with W3.

  The first surfaces F1 on both sides are connected symmetrically to the upper surfaces F2 (referred to as second surfaces) of the magnetic pole teeth 41 located on both sides in the circumferential direction of the center line C, respectively. The second surface F2 is formed at right angles to the center line C, and the width in the direction orthogonal to the center line C is set to R1. As a result, the first surface F1 is bent at a right angle through an appropriate R portion as it is, and is connected to the second surface F2, thereby forming orthogonal surfaces on both sides of the center line C.

  On the other hand, as shown in FIG. 4, the tooth tip portion 42 has a top portion 42A that forms a substantially T-shaped top portion when viewed from the axial direction, and a pillar portion (pillar) 42B that extends from one end portion of the top portion 42A. The top portion 42A and the column portion 42B are integrally formed by laminating a predetermined number of silicon steel plates punched into the shape shown in FIG.

  Among these, the upper surface of the top portion 42 </ b> A, that is, the radially outermost surface forms a stator side surface that creates a motor gap GP between the stator 12 and the rotor 11. In addition, an orthogonal surface is formed in the shoulder portion in charge of the connection between the top portion 42A and the support portion 42B below the top portion 42A when viewed from the axial direction. That is, on both sides in the circumferential direction of the tooth tip portion 42 (when the tooth tip portion 42 is attached to the magnetic pole teeth 41), the side surface F3 (hereinafter referred to as the third surface) over a range of a predetermined height H2 near the top of the support post portion 42B. And a lower surface F4 (hereinafter referred to as a fourth surface) of the top portion 42A are continuously formed. The third surface and the fourth surface form orthogonal surfaces on both sides in the circumferential direction. That is, when the tooth tip portion 42 is attached to the magnetic pole tooth 41, the third surfaces F3 on both sides are located across the center line C, and both the surfaces F3 are parallel to the center line C. Further, the fourth surfaces F4 on both sides are orthogonal to the center line C, and each of them has a predetermined diameter not larger than a predetermined diameter of the R portion connecting the first surface F1 and the second surface F2. It continues so that it may bend in the 3rd surface F3 via the R part.

  At this time, the width R2 of each of the fourth surfaces F4 located on both sides in the circumferential direction is almost equal to the width R1 of the second surface F2 described above. In addition, the height H2 of each of the third F3 located on both sides in the circumferential direction is equal to the height H1 of the first surface F1 described above or shorter than the height H1 by a predetermined length. . The distance between the third surfaces F3 located on both sides is substantially equal to the width W3 between the first surfaces F1 described above.

  Further, the shape of the outer surface of the rod-like portion excluding the third surface F3 of the support portion 42B is such that the clearance with the groove 41A of the magnetic pole tooth 41 is substantially constant when the tooth tip portion 42 is attached to the magnetic pole tooth 41. It is formed to become. That is, the width W4 (<W2) when viewed from the axial direction through the small step B from the third surface F3 is connected to the reduced width portion SR that gradually decreases toward the head portion. The leading portion TP of the reduced width portion SR is formed so as to draw a substantially semicircle having a constant radius so that the clearance between the bottom portion of the groove 41A is substantially constant when the tooth tip portion 42 is attached to the magnetic pole teeth 41. Yes.

  The stator 12 includes a plurality of silicon steel plates punched into an integral shape of the stator body 31 and a plurality of magnetic pole teeth 41, and a plurality of silicon steel plates punched into the shape of the tooth tip portion 42 using corresponding molds. It is formed by stacking. This situation in the case of the stator body 31 and the magnetic pole teeth 41 is schematically shown in FIG. Although partially shown in the figure, the cylindrical formwork 51 has two tip portions of the magnetic pole teeth 41 (both tip portions of the groove 41A forming the split structure) on both sides in the circumferential direction. A plurality of protrusions 51A for formation are formed at predetermined positions. A predetermined number of silicon steel plates after punching may be sequentially laminated so that the tips of the magnetic pole teeth 41 are locked to the protrusions 51A. Here, the protrusion 51A of the mold 51 and a portion adjacent to the protrusion 51A are set so as to be in close contact with the first surface F1 and the second surface F2 of each steel plate to be laminated. Therefore, it is possible to minimize the deviation between the steel plates of at least the first surface F1 and the second surface F2 of the laminated body obtained by an appropriate method such as adhesion and welding after lamination. The lamination method using the mold 51 is also applied to the tooth tip portion 42.

  FIG. 6 shows an insulator 34 formed by forming a resin material attached to the outside of each magnetic pole tooth 41 in a hollow / box shape. An upper surface and a lower surface in a predetermined direction of the insulator 34 are open, and instead, flanges 34A and 34B are provided at the ends. The size of the inside of the insulator 34 is formed to a size that can be fitted to the outer surface of each magnetic pole tooth 41. That is, the width of one side is substantially the same as W1, and the width of the other side is the width that substantially matches the stack thickness of the stacked body. For this reason, the flanges 34A and 34B are used as partitions at both ends, and the coil 35 is wound therebetween.

  When assembling the electric motor 10, the magnetic pole teeth 41 and the tooth tip portions 42 are respectively laminated and assembled in advance, and a coil 35 is wound around the insulator 34. Thereafter, each magnetic pole tooth 41 and the insulator 34 around which the coil 35 is wound are put on, and then, the column part 42B of the tooth tip part 42 is inserted and mounted in the groove 41A of each magnetic pole tooth 41.

  At this time, there is a relationship between the height H1 of the first surface F1 and the height H2 of the third surface F3 between the groove 41A and the support post portion 42B, that is, between the magnetic pole tooth 41 and the tooth tip portion 42. Since H2 <H1 and the stepped portion 42B of the tooth tip portion 42 is formed with a minute step B, it is substantially V-shaped when viewed from the axial direction and has a substantially constant gap. (Gap) SP is formed. The gap SP is filled with a filler such as an adhesive, so that when the motor 10 is driven, the tooth tip portion is caused by mechanical vibration applied to the motor itself and electromagnetic force applied to the tooth tip portion 42. 42 can be fixed so as not to be detached from the magnetic pole teeth 41.

  When the insulator 34 coiled around each magnetic pole tooth 41 is packaged and the tooth tip portion 42 is attached, the salient pole 32 is formed by these three members. The coils 35 of the plurality of (for example, 21) salient pole magnetic poles 32 formed in this way are divided into a plurality of groups so as to form a three-phase winding of U phase, V phase, and W phase (for example, Seven salient poles 32) are connected to each other. The winding lead-out end for each phase group is connected to a three-phase power supply circuit (not shown). Thereby, the rotor 11 is rotated by the three-phase rotating magnetic field created by the plurality of salient pole magnetic poles 32 of the stator 12.

  The electric motor 10 configured and functioning as described above can achieve the following effects.

  First, each of the plurality of teeth 33 basically stands up from the stator body 31 in the radial direction and has a plurality of magnetic pole teeth 41 having a divided structure that is divided in the circumferential direction through grooves 41A formed in the radial direction. And a tooth tip portion 42 having a top portion 42A that is fixed to each magnetic pole tooth 41 and provides a tip surface for the motor gap GP. For this reason, the circularity of the stator 12 can be easily secured and the structure can be strengthened only by paying attention to the connection between the magnetic pole teeth 41 and the tooth tip portions 42. For this reason, the salient pole magnetic pole structure which can endure high output torque can be provided. Further, since the circumferential width W5 (see FIG. 2) of the top portion 42A is formed wider than the circumferential width of each salient pole 32, the area where the electromagnetic force acts (area receiving the magnetic flux) can be increased. . As a result, even when the output is increased, it is possible to provide an electric motor that suppresses fluctuations in output (cogging, torque ripple), increases mechanical strength, prevents occurrence of vibration, and prevents the possibility of damage. it can.

  In addition, according to the present embodiment, various advantages can be ensured.

  First, the first surface F1 and the second surface F2 are formed on the tip portion of the magnetic pole tooth 41, and the third surface F3 and the fourth surface F4 are formed on the shoulder portion of the tooth tip portion 42. The tooth tip portion 42 is attached to the magnetic pole teeth 41 such that the first surface F1 and the third surface F3 are in contact with each other and the second surface F2 and the fourth surface F4 are in contact with each other. For this reason, in each salient pole 35, it is easy to more accurately determine the dimensions of the magnetic pole teeth 41 and the tooth tip portions 42 in the radial direction and the circumferential direction. For this reason, the dimensional variation of the tip portion of the teeth 33 can be suppressed only by the error due to the lamination (the lamination direction is the Z-axis direction in FIG. 1). As a result, the cogging due to the deviation of the roundness of the stator 12 can be reliably reduced.

  Further, the first surface F1 is formed at the tip portion of the magnetic pole teeth 41, the third surface F3 is formed at the shoulder portion of the tooth tip portion 42, and the first surface F1 and the third surface F3 are mutually formed. The tooth tip portion 42 is attached to the magnetic pole tooth 41 so as to abut. As a result, when this gap has a complicated shape, it may be difficult to assemble the gap to zero, and it is necessary to provide a gap with a further margin, according to this embodiment. Inconvenience can be eliminated.

  By the way, in general, a motor is manufactured by laminating plate materials such as electromagnetic steel plates, which are laminated using a laminating jig, and thereafter, adhesion, welding, and the like are performed. When the division part of the salient pole magnetic pole has a complex shape, the reference part of the stack will use the outer peripheral part other than the split part, the inner peripheral part, the salient pole magnetic pole, etc. The stacking accuracy of the portions is improved, but the stacking accuracy of the other portions is often not so good because the errors of die punching are accumulated. When the reference surface of the stacking jig is set to the entire circumference of the plate to be stacked, the error appears on all the surfaces. However, according to the present embodiment, since a plurality of flat surfaces which are the first to fourth surfaces F1 to F4 are combined, a reference surface at the time of stacking can be provided on the flat surface portion. Thereby, the clearance gap between flat parts (1st-4th surface F1-F4) can be made into zero, and a laminated body can be comprised by favorable positioning and dimensioning.

  Further, another advantage that the above-described flat portion gap is zero will be described. In general, when the salient pole magnetic pole is divided, a gap is likely to be generated at the divided portion. This gap acts as an interruption (gap) of the magnetic circuit, increases the magnetic resistance, reduces the amount of magnetic flux of the entire magnetic circuit, and deteriorates the characteristics. On the other hand, in the case of the electric motor 10 of the present embodiment, the gap between the flat portions (the first to fourth surfaces F1 to F4) can be reliably zero or substantially zero. The resistance can be minimized and good rotation characteristics can be obtained.

  In general, the gap between the rotor and stator of the motor (motor gap) is the portion with the highest magnetic resistance. The amount of magnetic flux per unit area of the electrical steel sheets that make up the stator is determined, but the area around the entire circumference of the stator is the maximum amount of magnetic flux that can be passed through the magnetic circuit. Get better. In general, the magnetoresistance of parts other than the gap is lower than that of the gap. In such a situation, if the salient poles are divided, the magnetic resistance at the portion other than the motor gap increases, and the rotational characteristics of the motor also deteriorate due to this increase. For this reason, when the salient pole magnetic pole has a split structure, it is desired to suppress the increase in magnetic resistance related to the split structure as much as possible. In this regard, according to the structure of the salient pole magnetic pole 32 according to the present embodiment, the gap between the flat portions (first to fourth surfaces F1 to F4) between the magnetic pole teeth 41 and the tooth tip portion 42 is zero. With the contact structure (or substantially zero), the facing area between the magnetic pole teeth 41 and the tooth tip portion 42 can be made larger than the area value. For this reason, local magnetic saturation due to the divided structure can be prevented, and a decrease in the rotational characteristics of the motor can be suppressed.

  Further, when the salient pole magnetic pole is provided with a divided structure as in the present embodiment, it is necessary to provide a gap in the radially opposed portion in order to keep the motor gap constant. In the present embodiment, the gap between the flat portions (the first to fourth surfaces F1 to F4) has a zero (or substantially zero) contact structure, but the other portions have a gap. It is necessary to provide it. Since this gap portion has a large magnetic flux resistance, it is a portion where the flow of magnetic flux is bad, but according to the present embodiment, it is formed in a substantially V shape, so that the portion where this magnetic flux flow is bad is the bottom of the V shape It is possible to concentrate only on (vertex). Further, by positioning the bottom portion at the base portion of the salient pole magnetic pole 32 of the stator 12, it is possible to further reduce the influence of the increase in magnetic resistance. Further, since the thickness of the magnetic pole teeth 41 in the circumferential direction becomes thicker toward the tooth root direction, it is preferable for increasing the rigidity of the salient pole magnetic poles 32.

  In addition, this invention is not limited to the thing of embodiment mentioned above, It can implement with a various form further within the range of the summary as described in a claim. For example, in the above-described embodiment, the electric motor in which the rotor is provided on the outer side of the stator in the radial direction is shown, but the present invention is also applied to an electric motor having a configuration in which the stator is arranged on the outer side in the radial direction and the rotor is arranged on the inner side. it can. In this case, the stator is provided with a plurality of teeth standing on the radially inner side of the cylindrical stator body, and each tooth has magnetic pole teeth divided in the circumferential direction through a groove formed in the radial direction. It can join and consist of a tooth tip part.

It is a schematic sectional drawing of the axial direction (direction along a motor rotating shaft) which shows the structure of the electric motor which concerns on one Embodiment of this description. It is an external appearance view of the axial direction which shows the structure of the salient pole magnetic pole of the stator used in the embodiment. It is an external view of the axial direction which shows the structure of the magnetic pole tooth of each salient pole magnetic pole. It is an external view of the axial direction which shows the structure of the tooth tip part of each salient pole magnetic pole. It is explanatory drawing explaining the lamination | stacking operation | work of the stator using a formwork. It is a perspective view of the insulator used when winding a coil on each salient pole magnetic pole.

Explanation of symbols

10 Electric motor 11 Rotor (rotor)
12 Stator (stator)
31 Stator body

Claims (10)

  A stator that is fixedly arranged, and a rotor that is rotatably supported facing the stator with a predetermined amount of gap in the radial direction. The stator includes a substantially cylindrical stator body, and the stator body In an electric motor in which a current-carrying coil is wound around a plurality of teeth formed so as to protrude in the radial direction from the stator body at a predetermined position in the circumferential direction, a salient pole magnetic pole is formed. Each of the magnetic pole teeth stands in the radial direction from the stator body and is divided in the circumferential direction through a groove formed in the radial direction, and is integrated with the groove and the tip of the magnetic pole tooth. And a tooth tip portion having a top portion that is combined and fixed to the magnetic pole tooth to provide the tip surface, and the circumferential width of the top portion is wider than the circumferential width of the salient pole. An electric motor, characterized in that the form was.    The groove of the magnetic pole tooth is formed in a shape that becomes narrower as it reaches the stator body side when viewed from the axial direction of the stator, and the tooth tip portion is formed with a pillar corresponding to the shape of the groove of the magnetic pole tooth, Formed as a substantially wedge-shaped member having the apex at one end in the longitudinal direction of the pillar, and inserting the pillar into the groove allows the apex to be positioned at the tip of the magnetic pole tooth. The electric motor according to claim 1, wherein the electric motor is mounted on a magnetic pole tooth.   Each of the circumferentially opposite side portions of the tooth tip portion that transition from the pillar to the top portion is formed on a perpendicular surface when viewed from the axial direction, and from the groove of the magnetic pole tooth to the tip surface thereof The shoulder portions in the circumferential direction that crawl up are formed on orthogonal surfaces that are perpendicular to each other when viewed from the axial direction, and two orthogonal surfaces in the circumferential direction of the tooth tip portion and in the circumferential direction of the magnetic pole teeth The electric motor according to claim 2, wherein the tooth tip portion is attached to the magnetic pole teeth so that the two orthogonal surfaces are in close contact with each other.   The two orthogonal surfaces of the magnetic pole teeth each have a first surface parallel to a center line extending in the radial direction through the circumferential center position of each tooth, and a second surface orthogonal to the first surface. Each of the two orthogonal surfaces of the tooth tip portion, and a third surface parallel to the center line when the tooth tip portion is attached to the magnetic pole tooth, The electric motor according to claim 3, comprising a fourth surface orthogonal to the surface.   The groove portion excluding the two orthogonal surfaces of the groove portions of the magnetic pole teeth has a substantially V-shape that becomes narrower when viewed from the axial direction as it goes to the stator body side, A portion of the pillar excluding the two orthogonal planes has a tapered shape that becomes thinner as it proceeds toward the tip opposite to the top and is substantially V-shaped when viewed from the axial direction, 5. The gap according to claim 4, wherein when the tooth tip portion is attached to the magnetic pole tooth, a gap of a predetermined distance is formed between the pillar and the groove except for the portions of the two orthogonal surfaces. The electric motor described.   The electric motor according to claim 5, wherein the gap of the predetermined distance between the pillar and the groove is filled with a filler such as an adhesive.   The sum of the circumferential widths of the two second surfaces located on both sides in the circumferential direction of the groove of the magnetic pole teeth and the circumferential directions of the two fourth surfaces located on both sides in the circumferential direction of the pillar of the tooth tip portion 7. The electric motor according to claim 4, wherein the total width is substantially the same.   The radial lengths of the two first surfaces located on both sides in the circumferential direction of the groove of the magnetic pole teeth are set to the lengths of the two third surfaces located on both sides in the circumferential direction of the pillar. 8. The electric motor according to claim 4, wherein the electric motor is formed longer than a length in a radial direction.   The electric motor according to any one of claims 1 to 8, wherein a groove of the magnetic pole teeth of the magnetic pole teeth has a depth equivalent to that of the stator body.   The electric motor according to any one of claims 1 to 9, wherein the stator including the teeth including the magnetic pole teeth and the tooth tip portion is a member formed by laminating thin steel plates.

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