JP2008182852A - Resolver stator fixing structure and brushless motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing structure of a resolver stator, having a simple structure and positively fixing a resolver stator, thereby reducing the manufacturing cost of a brushless motor using a resolver. <P>SOLUTION: The resolver 33 having the resolver stator 34 provided with a circular resolver core 51 and a resolver rotor 35 is fixed so as to baffle and come off in a housing 31. The housing 31 is provided with a resolver stator accommodating portion 54 for accommodating the resolver stator 34. A caulking portion 53 in which an internal circumferential surface 54b near an opening protrudes in a center direction is provided on the circumferential edge 54a of the opening of the stator accommodating portion 54. The caulking portion 53 is formed on a portion where a concave portion 52 exists and a portion where it does not exists, of the external circumferential surface of the resolver core, and the caulking portion 53 protrudes and engages with the concave portion 52 in the former and the caulking portion 53 abuts on the external circumferential surface of the resolver core 51 in the latter. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a resolver used as an angle sensor for a brushless motor or the like, and more particularly to a resolver stator fixing structure in a brushless motor used for an electric power steering device or the like.

  In recent years, many vehicles have been equipped with so-called power steering devices for assisting steering force of automobiles and the like. As such power steering devices, in recent years, vehicles equipped with electric power steering devices (so-called electric power steering devices) are increasing from the viewpoint of reducing engine load and weight. In this electric power steering device (hereinafter abbreviated as EPS), the motor as a driving source thereof is required to be downsized and high in performance because the device is arranged in a narrow bonnet space. Conventionally, DC motors with brushes have been widely used as such motors, but recently, with the improvement of control technology, the adoption of brushless motors that are superior in terms of miniaturization and high performance has increased. is doing. However, a brushless motor is still more expensive than a brushed motor, and how to manufacture the motor in an anchor, including a method for processing a single part, is also a major issue.

  On the other hand, in the brushless motor, in order to rotationally drive the rotor, it is necessary to detect the rotational position of the rotor and sequentially excite the stator side coil (stator coil) based on the detected rotor rotational position. Conventionally, detection devices using encoders, Hall ICs, and the like have been used for detecting the rotational position of the rotor. However, in recent years, high-resolution sensors have been required due to demands for higher performance and lower noise in brushless motors. The use of resolvers, which are one of non-contact rotation sensors, is also increasing.

  The resolver generally includes a resolver rotor that rotates together with the rotor of the motor, and a resolver stator that is disposed outside the resolver rotor, and a high frequency signal is applied to an excitation coil of the resolver stator. The resolver rotor has convex portions in three directions, and the phase of the signal output from the detection coil changes due to the proximity of the convex portions. By comparing this detection signal with the reference signal, the rotational position of the rotor of the brushless motor is detected, the current to the stator coil is appropriately switched based on the rotor rotational position, and the brushless motor is driven to rotate.

  As described above, the resolver has high detection accuracy, has a simple structure and is not easily damaged, and is resistant to high temperatures and vibration environments. Therefore, the resolver is increasingly used for an in-vehicle motor, particularly an EPS. FIG. 4 is an explanatory diagram showing the configuration of the resolver stator of the EPS brushless motor, and FIG. 5 is an explanatory diagram showing the mounting structure of the resolver stator of FIG. As shown in FIG. 4, the resolver stator 101 includes an iron core 102, an insulator 103 attached to the iron core 102, and a coil 104 wound around the iron core 102 via the insulator 103. The iron core 102 has a structure in which a large number of steel plates are laminated, and is formed in a ring shape. The insulator 103 is made of synthetic resin, and a coil 104 made of a copper wire is wound around the outside thereof.

  On the other hand, a resolver stator accommodating portion 106 having a cylindrical hole shape is formed in the housing 105 of the brushless motor. The resolver stator 101 is housed and fixed in the resolver stator housing portion 106. In this case, the resolver stator 101 is press-fitted and fixed to the resolver stator housing portion 106, or is bonded and fixed using an adhesive (or both). As described above, the resolver is a rotational position sensor of the rotor, and the angle deviation of the resolver stator 101 is directly related to the control problem. Therefore, the resolver stator 101 needs to be treated so that the mounting angle is not displaced in any environment. . However, in the case of the resolver as shown in FIG. 5, the resolver stator 101 may be displaced in the circumferential direction and the axial direction due to vibration or the like, which may adversely affect the detection accuracy. For this reason, in order to secure detection accuracy, the following two fixing methods are conventionally used to mechanically fix the resolver stator 101.

  FIG. 6 is an explanatory diagram showing the configuration of the first fixing method. As shown in FIG. 6, here, the resolver stator 101 is accommodated in a bottomed cylindrical resolver holder 107. The resolver holder 107 is made of iron, and a holder fixing piece 108 projects from the opening end of the resolver holder 107 in the radial direction. A long screw hole 109 is formed in the holder fixing piece 108, and the resolver holder 107 is fixed to the housing 105 by a screw 110 inserted through the screw hole 109. In the first fixing method, it is also possible to provide the resolver stator 101 itself with a flange portion without using the resolver holder 107 and screw this to the housing 105. However, since it is difficult and expensive to produce the resolver stator 101, it is not very suitable for mass production, and the method using the resolver holder 107 is more general.

FIG. 7 is an explanatory diagram showing the configuration of the second fixing method. As shown in FIG. 7, here, a convex portion 111 is formed in the resolver stator 101, and this is fitted into a concave portion 112 formed in the housing 105. In the second fixing method, no resolver holder is used, and the resolver stator 101 is prevented from rotating by fitting the convex portion 111 and the concave portion 112 directly formed on the resolver stator 101.
JP 2005-300410 A

  However, in the first fixing method described above, it is necessary to secure a screwing space in the motor, and there is a problem that the layout of the motor components is hindered. In particular, EPS motors are often severely limited in the radial dimension, and it is difficult to secure a screwing portion in the radial direction, which hinders miniaturization of the motor. In addition, because the structure requires the resolver holder 107 and the screw 110, there is a problem that the number of parts is increased correspondingly and this causes an increase in cost.

  Next, in the second fixing method, although the problem of an increase in the number of parts does not occur, it is necessary to form the convex portion 111 on the resolver stator 101. In general, a resolver stator employs a rotating lamination method in which steel plates formed by pressing are stacked one by one while rotating, thereby stabilizing the magnetic balance including iron loss and hysteresis loss. ing. However, it is difficult to provide a convex portion at one location on the outer periphery of the resolver stator 101 by rotating lamination, as shown in FIG. Further, in order to provide the housing 105 with the concave portion 112 with high accuracy, processing such as cutting is necessary, and the manufacturing cost increases. As described above, both the first and second fixing methods inevitably increase the cost, hinder the request to reduce the motor price, and the improvement has been demanded.

  An object of the present invention is to provide a fixing structure of a resolver stator that can securely fix a resolver stator while having a simple structure, and to reduce the manufacturing cost of a brushless motor using the resolver.

  The resolver stator fixing structure of the present invention fixes a resolver having a stator having an annular steel core and a rotor rotatably disposed inside the stator in a housing. The resolver stator fixing structure is provided with a cylindrical hole-shaped stator accommodating portion that can accommodate the stator, and is formed on the outer peripheral surface of the core at the periphery of the opening of the stator accommodating portion. Corresponding to the recessed portion, a bulging portion is provided in which an inner peripheral surface in the vicinity of the opening is protruded in the center direction, and the bulging portion is protruded into the recessed portion.

  In the present invention, since the bulging portion formed in the housing protrudes into the concave portion of the resolver core, the circumferential movement of the resolver core is regulated by the bulging portion that has entered the concave portion, and the resolver core is placed in the stator housing portion. Fixed in a locked state. In this case, the concave portion of the resolver core is conventionally provided for positioning when the core is formed, and by using this, the resolver stator is fixed to the housing, so that the cost of the resolver stator is not increased. A detent can be performed.

  In the fixing structure of the resolver stator, a bulging portion that projects an inner peripheral surface in the vicinity of the opening in the center direction is further provided at a portion of the stator housing portion where the recess is not present on the periphery of the opening. The protruding portion may be brought into contact with the outer peripheral portion of the core. The contact of the bulging portion restricts the movement of the resolver core in the axial direction, and the resolver core is prevented from coming off in the axial direction.

  Further, the bulging portion may be formed by crushing the peripheral edge of the opening from the axial direction. For example, the bulging portion may be formed by a cokin treatment or the like.

  On the other hand, a brushless motor of the present invention is provided with a stator including a stator core and a field coil wound around the stator core, and rotatably disposed inside or outside the stator. A resolver comprising a rotor having a fixed rotor core and a magnet attached to the rotor core, a resolver rotor attached to the rotor shaft, and a steel core disposed outside the resolver rotor and formed in an annular shape. A brushless motor having a stator and a housing having a cylindrical hole-shaped stator accommodating portion capable of accommodating the resolver stator, on a peripheral edge of the opening of the stator accommodating portion, on an outer peripheral surface of the core Corresponding to the formed recess, a bulging portion is provided that projects the inner peripheral surface in the vicinity of the opening in the center direction, The output unit is characterized in that protrudes in the recess.

  In the present invention, since the bulging portion formed in the housing protrudes into the concave portion of the resolver core, the resolver core is fixed in a state of being prevented from rotating in the stator housing portion. In this case, the concave portion of the resolver core is conventionally provided for positioning when the core is formed, and by using this, the resolver stator is fixed to the housing, so that the cost of the resolver stator is not increased. A detent can be performed.

  In the brushless motor, a bulging portion that projects an inner peripheral surface in the vicinity of the opening in the center direction is further provided at a portion of the stator housing portion where the recess is not present on the periphery of the opening, and the bulging portion is provided. You may make it contact | abut to the outer peripheral part of the said core. The contact of the bulging portion restricts the movement of the resolver core in the axial direction, and the resolver core is prevented from coming off in the axial direction.

  According to the fixing structure of the resolver stator of the present invention, a resolver for fixing a resolver having a stator having an annular steel core and a rotor rotatably disposed inside the stator in the housing. In the stator fixing structure, a bulge is formed at the periphery of the opening of the stator housing provided in the housing, with the inner peripheral surface in the vicinity of the opening protruding in the center direction corresponding to the recess formed in the outer peripheral surface of the core The bulging part protrudes into the concave part of the outer peripheral surface of the core, thereby restricting the circumferential movement of the resolver core by the bulging part that has entered the concave part, and the resolver core is prevented from rotating in the stator housing part. It becomes possible to fix with. As a result, it is possible to prevent the resolver stator from rotating without incurring a large cost increase, and it is possible to reduce the size of the motor using the resolver as compared with the conventional fixing method. In addition, since the number of parts and difficult processing / assembly processes are not required, it is possible to reduce the manufacturing cost of a motor using the resolver.

  Further, according to the brushless motor of the present invention, the stator including the stator core and the field coil, the rotor rotatably disposed inside or outside the stator, and the rotor shaft of the rotor are attached. In a brushless motor comprising a resolver rotor, a resolver stator having an annular steel core disposed outside the resolver rotor, and a housing having a cylindrical hole-shaped stator accommodating portion capable of accommodating the resolver stator. A bulging portion is provided on the periphery of the opening of the stator accommodating portion corresponding to the concave portion formed on the outer peripheral surface of the core so that the inner peripheral surface in the vicinity of the opening protrudes in the center direction. By projecting into the recess on the outer peripheral surface, the bulging part that has entered the recess restricts the circumferential movement of the resolver core and prevents the resolver core from rotating in the stator housing part. It is possible to fix. As a result, it is possible to prevent the resolver stator from rotating without incurring a large cost increase, and it is possible to reduce the size of the motor as compared with a motor employing a conventional fixing method. Further, since the number of parts and difficult machining / assembly processes are not required, it is possible to reduce the manufacturing cost of the motor.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing a configuration of a brushless motor to which the present invention is applied. A motor 1 shown in FIG. 1 is used as a power source for a rack-assisted EPS, and has a configuration in which a rack shaft 2 penetrates the motor 1. The rotation of the motor 1 is transmitted to the rack shaft 2 via the ball screw mechanism 3 and becomes a steering assist force.

  The motor 1 has an inner rotor type device configuration in which a stator 11 is disposed outside and a rotor 21 is disposed inside. The stator 11 includes a housing 12, a stator core 13 fixed to the inner peripheral side of the housing 12, and a winding 14 wound around the stator core 13. The housing 12 is formed of iron or the like, and the outer periphery thereof is suppressed to about 100 mm in response to a request for miniaturization of the motor. The stator core 13 has a structure in which a large number of steel plates are laminated, and a plurality (9 in this case) of teeth 16 project from the inner peripheral side of the stator core 13. A coil is wound around a slot (nine slots) formed between the teeth 16 to form a winding 14. Winding 14 is connected to a battery (not shown) via power supply wiring 15.

  The rotor 21 is disposed inside the stator 11 and has a configuration in which a cylindrical rotor shaft 22, a rotor core 23, a magnet 24, and a magnet cover 25 are arranged coaxially. The rack shaft 2 is inserted inside the rotor shaft 22. A cylindrical rotor core 23 is externally provided on the outer periphery of the rotor shaft 22. A magnet 24 having a 6-pole configuration is fixed to the outer periphery of the rotor core 23.

  The magnet 24 is a rare earth magnet such as a neodymium iron magnet that is small and has a high magnetic flux density. Thus, by using a rare earth magnet for the magnet 24, the motor can be miniaturized, the inertia of the rotor 21 is reduced, and the steering feeling is improved. The magnet 24 has a ring shape, and a plurality of magnetic poles are alternately arranged N and S in the circumferential direction. A plurality of segment magnets may be used as the magnet 24. A magnet cover 25 is externally provided on the outside of the magnet 24 so that even if the magnet is broken, the motor 1 is not locked by the broken piece.

  An aluminum die cast housing 31 is attached to the right end side of the housing 12 in the figure. The housing 31 accommodates a bearing 32 that supports the right end side of the rotor 21 and a resolver 33 that detects the rotation of the rotor 21. The resolver 33 includes a resolver stator 34 that is housed and fixed in the resolver stator housing portion 54 of the housing 31, and a resolver rotor 35 that is secured to the rotor 21 side. A coil 36 is wound around the resolver stator 34, and an excitation coil and a detection coil are provided. The resolver stator 34 has the same configuration as that of the resolver stator 101 of FIG. 4, and a coil 36 is wound around an annular resolver core 51 formed by laminating a plurality of steel plates via an insulator (not shown). It has become the composition.

  FIG. 2 is an explanatory view showing a fixing structure of the resolver stator 34 in the motor 1. As shown in FIG. 2, on the outer periphery of the resolver core 51, in order to rotationally stack the resolver stator, positioning concave portions 52 are equally provided along the circumferential direction. Here, since the recessed part 52 is formed with a press die at the time of steel plate shaping | molding, it is formed in the outer periphery of the resolver core 51 with comparatively high precision. On the other hand, since the concave portion 52 is used for positioning when the resolver core 51 is rotated and laminated, if the resolver stator 34 is inserted and set at a predetermined position in the housing 31, the concave portion 52 is always arranged at a predetermined position. . Therefore, in the motor 1, by utilizing this property, a portion that protrudes into the recess 52 is formed in the housing 31 using a fastening method such as a caulking punch, and the circumferential stop of the resolver stator 34 and the axial direction Retaining is performed mechanically.

  As shown in FIG. 2, the housing 31 of the motor 1 is provided with a plurality of caulking portions (bulging portions) 53 formed by caulking punching using caulking chisel or the like. The caulking portion 53 is formed in such a manner that the opening peripheral edge 54a of the resolver stator accommodating portion 54 is crushed from the axial direction by caulking punches. Thereby, in the resolver stator accommodating part 54, the inner peripheral surface 54b in the vicinity of the opening part bulges slightly toward the center direction. In the motor 1, such a cokin portion 53 is provided in a portion where the concave portion 52 of the resolver core 51 exists and a portion where the concave portion 52 does not exist. FIG. 3A is an enlarged view of the coke portion 53 (A portion in FIG. 2) in the portion where the recess 52 exists, and FIG. 3B is a coke portion 53 (B portion in FIG. 2) in the portion where the recess 52 does not exist. FIG.

  As shown in FIG. 3 (a), at the portion where the recess 52 exists, the inner peripheral bulging portion of the coke portion 53 protrudes into the recess 52. In other words, at the concave portion existing portion, the cokin portion 53 enters the concave portion 52, and the coking portion 53 is in pressure contact with the opening edge portion 52a of the concave portion 52, and both are engaged. As a result, the resolver stator 34 (resolver core 51) is restricted from moving in the circumferential direction and is prevented from rotating around the inner peripheral surface 54b of the resolver stator accommodating portion 54. In addition, the axial contact of the resolver stator 34 is restricted by the press contact between the caulking portion 53 and the opening edge portion 52a, so that the resolver stator 34 is prevented from coming off in the axial direction.

  On the other hand, at the portion where the recess 52 does not exist, the inner peripheral bulge portion of the coke portion 53 is in contact with the outer peripheral portion 51 a of the resolver core 51 as shown in FIG. In other words, the cokin 53 is in pressure contact with the resolver core 51 at the recess-existing portion. Accordingly, the resolver stator 34 is restricted from moving in the axial direction and is prevented from being detached from the inner peripheral surface 54 b of the resolver stator accommodating portion 54. As described above, the resolver stator 34 is prevented from being rotated and prevented from coming off by the engagement of the coke part 53 and the concave part 52 at the concave part existence site. However, the contact between the coke part 53 and the resolver core 51 at the concave part absent part is performed. The contact prevents the resolver stator 34 from coming off.

  3B, there is a detent effect due to the contact between the coke portion 53 and the resolver core 51 even in the absence of the recess portion as shown in FIG. 3B. However, the detent of the resolver stator 34 is exclusively between the coke portion 53 and the recess 52. Secured by engagement. Further, the coke 53 and the opening edge 52a are not necessarily in contact with each other at the recessed portion as shown in FIG. 3A. In this case, the resolver stator 34 is prevented from coming off by the recessed portion absent portion. .

  As described above, in the fixing structure of the resolver stator 34 according to the present invention, the resolver stator 34 is fixed to the housing 31 by using the concave portion 52 that has existed in the past, so that the cost of the resolver stator 34 can be increased without incurring a large cost increase. Stopping and retaining can be performed. For this reason, a screwing space is not required as compared with the conventional fixing method, and the motor can be miniaturized. In addition, since the resolver holder and screws are not required, the number of parts can be reduced, and further, cutting and difficult processing / assembly processes are not required when fixing the resolver stator 34, thereby reducing the cost of the brushless motor. It becomes possible.

  Further, in this embodiment, since the processing method that is highly reliable and excellent in cost performance is used, the resolver stator 34 can be reliably and inexpensively fixed. For this reason, it becomes possible to reduce the product cost without impairing the reliability of the product. In addition, since the concave portion 52 of the resolver stator 34 is formed with high accuracy, the coking process can be automated, and the fixing structure can be employed without increasing the manufacturing cost.

  On the other hand, a resolver rotor 35 fixed to the rotor shaft 22 is disposed inside the resolver stator 34. The resolver rotor 35 has a configuration in which metal plates are laminated, and has convex portions in three directions. When the rotor shaft 22 rotates, the resolver rotor 35 also rotates in the resolver stator 34. A high frequency signal is given to the exciting coil of the resolver stator 34, and the phase of the signal output from the detection coil changes due to the proximity of the convex portion. The rotational position of the rotor 21 is detected by comparing the detection signal with the reference signal. Then, based on the rotational position of the rotor 21, the current to the winding 14 is appropriately switched, and the rotor 21 is rotationally driven.

  A housing 41 made of aluminum die casting is attached to the left end side of the housing 12 in the drawing. A ball screw mechanism 3 is incorporated in the housing 41. The ball screw mechanism 3 includes a nut portion 42, a screw portion 43 formed on the outer periphery of the rack shaft 2, and a large number of balls 44 interposed between the nut portion 42 and the screw portion 43. . The rack shaft 2 is supported so as to be reciprocable in the left-right direction by the nut portion 42 in a state where the rotation around the shaft is restricted, and moves in the left-right direction as the nut portion 42 rotates.

  The nut portion 42 is fixed to the left end portion of the rotor shaft 22 and is rotatably held by an angular bearing 45 fixed to the housing 41. The angular bearing 45 is fixed in a state where axial movement is restricted between bearing fixing rings 46 a and 46 b screwed into the opening of the housing 41 and a stepped portion 47 formed inside the housing 41. ing. The axial movement between the nut portion 42 and the angular bearing 45 is restricted by a bearing fixing ring 48 screwed into the left end of the nut portion 42 and a step portion 49 formed on the outer periphery of the nut portion 42. Is done.

  In an EPS equipped with such a motor 1, the steering handle is first operated to rotate the steering shaft, and the rack shaft 2 is moved in a direction corresponding to this rotation to perform a steering operation. When a steering torque sensor (not shown) is activated by this operation, electric power is supplied from the battery to the winding 14 via the power supply wiring 15 according to the detected torque. When electric power is supplied to the winding 14, the motor 1 operates and the rotor shaft 22 rotates. When the rotor shaft 22 rotates, the nut portion 42 coupled therewith rotates, and the steering assist force in the axial direction is transmitted to the rack shaft 2 by the action of the ball screw mechanism 3. Thereby, the movement of the rack shaft 2 is promoted, and the steering force is assisted.

It goes without saying that the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention.
For example, in the above-described embodiment, the description has been given of the case where five positioning concave portions 52 are formed in the resolver stator 34. However, the number of the concave portions 52 is not limited to this, and the number of the concave portions 52 is three or four. Alternatively, the present invention can be applied to six or more resolver stators. Of course, the present invention can be applied to the case where the number of the recesses 52 is one, but from the viewpoint of the effect of fixing the resolver stator, it is preferable that there are two or more recesses 52. Further, in the above-described embodiment, an example in which the caulking process is used for fixing the resolver stator 34 has been described. However, any other processing method may be used as long as it is a fastening method capable of a similar fixing structure.

  Furthermore, in the above-described embodiment, the example in which the resolver stator fixing structure according to the present invention is used for a brushless motor used as an EPS drive source is shown. However, the fixing structure is not limited to an EPS brushless motor, It can be widely applied to brushless motors of Further, the present invention can be applied to a general-purpose resolver stator fixing structure that is not limited to a brushless motor.

It is sectional drawing which shows the structure of the brushless motor to which this invention is applied. It is explanatory drawing which shows the fixing structure of the resolver stator in the motor of FIG. (A) is an enlarged view of the cochin part (A part of FIG. 2) in the site | part in which a recessed part exists, (b) is an enlarged view of the coke part (B part of FIG. 2) in the part in which a recessed part does not exist. It is explanatory drawing which shows the structure of the resolver stator of the brushless motor for EPS. It is explanatory drawing which shows the attachment structure of the resolver stator of FIG. It is explanatory drawing which shows the structure of the 1st fixing system of a resolver stator. It is explanatory drawing which shows the structure of the 2nd fixing system of a resolver stator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motor 2 Rack shaft 3 Ball screw mechanism 11 Stator 12 Housing 13 Stator core 14 Winding 15 Power supply wiring 16 Teeth 21 Rotor 22 Rotor shaft 23 Rotor core 24 Magnet 25 Magnet cover 31 Housing 32 Bearing 33 Resolver 34 Resolver stator 35 Resolver rotor 36 Coil 41 Housing 42 Nut portion 43 Screw portion 44 Ball 45 Angular bearing 46a, 46b Bearing fixing ring 47 Step portion 48 Bearing fixing ring 49 Step portion 51 Resolver core 51a Outer peripheral portion 52 Recessed portion 52a Opening edge portion 53 Cokin portion 54 Resolver stator housing portion 54a Opening peripheral edge 54b Inner peripheral surface
101 resolver stator
102 iron core
103 Insulator
104 coils
105 Housing
106 Resolver stator housing
107 Resolver holder
108 Holder fixing piece
109 Screw hole
110 screws
111 Convex
112 recess

Claims (5)

A resolver stator fixing structure for fixing a resolver in a housing having a stator having a steel core formed in an annular shape and a rotor rotatably disposed inside the stator. ,
The housing includes a cylindrical hole-shaped stator accommodating portion that can accommodate the stator,
A bulging portion is provided on the peripheral edge of the opening of the stator accommodating portion, corresponding to a recess formed on the outer peripheral surface of the core, with an inner peripheral surface in the vicinity of the opening projecting in the center direction. A structure for fixing a resolver stator, wherein a portion protrudes into the recess.   The resolver stator fixing structure according to claim 1, wherein a bulging portion is provided at a portion where the concave portion on the periphery of the opening portion of the stator housing portion does not exist so that an inner peripheral surface in the vicinity of the opening portion protrudes in the center direction. A fixing structure of a resolver stator, wherein the bulging portion is brought into contact with an outer peripheral portion of the core.   3. The resolver stator fixing structure according to claim 1, wherein the bulging portion is formed by crushing the periphery of the opening from the axial direction. A stator comprising a stator core and a field coil wound around the stator core;
A rotor that is rotatably arranged inside or outside the stator and includes a rotor shaft, a rotor core fixed to the rotor shaft, and a magnet attached to the rotor core;
A resolver rotor attached to the rotor shaft;
A resolver stator including a steel core disposed outside the resolver rotor and formed in an annular shape;
A brushless motor having a housing provided with a cylindrical hole-shaped stator accommodating portion capable of accommodating the resolver stator,
A bulging portion is provided on the peripheral edge of the opening of the stator accommodating portion, corresponding to a recess formed on the outer peripheral surface of the core, with an inner peripheral surface in the vicinity of the opening projecting in the center direction. A brushless motor characterized in that a portion protrudes into the recess.   5. The brushless motor according to claim 4, wherein a bulging portion that projects an inner peripheral surface in the vicinity of the opening in a central direction is provided at a portion of the stator housing portion where the recess is not present on the periphery of the opening. A brushless motor characterized in that a protruding portion is brought into contact with an outer peripheral portion of the core.

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