JP2007028706A - Stator and brushless motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stator which can be attached easily while reducing the size. <P>SOLUTION: The stator 20 comprises a stator core 23 equipped with a ring-shaped annular portion 21 and a plurality of teeth 22 extending radially from the annular portion 21, and a cylindrical yoke 24 having an inner circumferential surface 24a fixed with the outer diameter side end 22a of the teeth 22 and an outer circumferential surface 24b composed of a magnetic body forming the outer circumferential surface of a motor. The outer circumferential surface 22b at the outer diameter side end 22a of the teeth 22 is a curved surface extending along the inner circumferential surface 24a of the yoke 24 and the stator core 23 is secured to the yoke 24 by press fitting the outer circumferential surface 22b at the outer diameter side end 22a to the inner circumferential surface 24a of the yoke 24. A recess 27 extending in the axial direction is formed in the circumferential center at the outer diameter side end 22a of the teeth 22. A protrusion 28 engaging with the recess 27 is provided on the inner circumferential surface 24a of the yoke 24 to project therefrom and extend in the axial direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a stator and a brushless motor in an inner rotor type brushless motor.

2. Description of the Related Art Conventionally, some inner rotor type brushless motors include a stator core as disclosed in Patent Document 1, for example.
The stator core of the above publication has a ring-shaped outer core and a plurality of teeth that extend linearly in the radial direction and wind the windings, and are arranged in the circumferential direction at equal intervals in the circumferential direction. And an inner core formed with a rotor receiving hole at the inner peripheral portion thereof, and the inner peripheral portion of the outer core and the outer end portion of the teeth are connected to each other. Then, the inner peripheral surface of the yoke is press-fitted and fixed to the outer peripheral surface of the outer core, so that the stator formed by winding the winding around the stator core is fixed to the inner peripheral surface of the bottomed cylindrical yoke.

In such a stator core, before connecting the outer core and the inner core, the winding can be wound around the teeth of the inner core, and in this case, since the winding can be wound from the outside of the teeth, Winding work is easy and the space factor of the winding can be improved.
JP 2004-64925 A

  By the way, with the above conventional configuration, the outer core and the yoke overlap in the radial direction, leading to an increase in the size of the motor. Moreover, since there are a plurality of fixing portions to the outer core of the inner core and the concave and convex press fitting, in order to press-fit these fixing portions in the circumferential direction and the radial direction, it is necessary to process the fixing portions with high accuracy. The assembly work was not easy.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide a stator and a brushless motor that can be reduced in size and can be easily assembled.

  In order to solve the above-mentioned problem, the invention according to claim 1 is directed to a stator core including a ring-shaped annular portion and a plurality of teeth extending in a radial direction from the annular portion, and an outer diameter side end portion of the teeth being an inner portion. A cylindrical yoke made of a magnetic material fixed to the peripheral surface and having an outer peripheral surface forming the outer peripheral surface of the motor.

  According to a second aspect of the present invention, in the stator according to the first aspect, the outer peripheral surface of the outer diameter side end portion of the teeth has a curved shape along the inner peripheral surface of the yoke, and the outer diameter side end The stator core is fixed to the yoke by press-fitting and fixing the outer peripheral surface of the portion to the inner peripheral surface of the yoke.

  According to a third aspect of the present invention, in the stator according to the first aspect, the outer diameter side end portion of the teeth is press-fitted into the inner peripheral surface of the yoke from the circumferential center line of the teeth toward the outer side in the circumferential direction. The bill is set to gradually increase.

According to a fourth aspect of the present invention, in the stator according to any one of the first to third aspects, a recess extending in the axial direction is formed at a circumferential central portion of the outer diameter side end portion of the teeth. ing.
According to a fifth aspect of the present invention, in the stator according to the fourth aspect, the inner peripheral surface of the yoke is provided with a convex portion that protrudes from the inner peripheral surface and extends in the axial direction and engages with the concave portion. Have been.

  The invention according to claim 6 is the stator according to any one of claims 1 to 5, wherein the outer diameter side end portion of the teeth extends to both sides in the circumferential direction with respect to the teeth. A flange portion having a radial width of at least one half of the circumferential width of the teeth and a circumferential width of at least one half of the circumferential width of the teeth is formed. A stator core is fixed to the inner peripheral surface of the yoke.

  A seventh aspect of the present invention is the stator according to any one of the first to sixth aspects, wherein the outer peripheral surface of the yoke has a cylindrical shape made of a magnetic material at an outer portion where the stator core is press-fitted. The annular magnetic member was further provided.

According to an eighth aspect of the present invention, in the stator according to the first to seventh aspects, the stator core has a skewed slot.
According to a ninth aspect of the present invention, the stator according to any one of the first to eighth aspects of the present invention and the stator are rotatably disposed inside the stator and rotated by a rotating magnetic field generated by the stator. A brushless motor comprising a rotor.

  A tenth aspect of the present invention is the brushless motor according to the ninth aspect, wherein the brushless motor opens and closes a valve provided in an intake pipe that controls the speed or direction of air flowing into the engine combustion chamber.

(Function)
According to the first aspect of the present invention, since the stator is configured by fixing the stator core to the yoke, the stator includes the inner core and the outer core, which are inserted and fixed in the yoke to configure the yoke. Compared to the case, the stator is reduced in diameter and reduced in size. Moreover, since the number of parts which comprise a stator is reduced, cost reduction can be aimed at. Further, since the stator can be formed by fixing the stator core to the inner peripheral surface of the yoke, it can be easily assembled. Therefore, the motor can be reduced in size and can be easily assembled.

  According to the second aspect of the invention, since the outer peripheral surface of the outer diameter side end portion of the tooth is a curved shape along the inner peripheral surface of the yoke, the outer peripheral surface of the outer diameter side end portion of the tooth is the yoke. All the outer peripheral surfaces of the outer diameter side end portions of the teeth become magnetic passage surfaces. Therefore, the magnetic flux efficiently flows from the teeth to the yoke, and the thickness of the yoke can be reduced compared to the case where there is a magnetic resistance in this portion, and the stator can be downsized.

  According to the third aspect of the invention, the outer diameter side end portion of the teeth is set so that the press-fitting allowance of the yoke gradually increases from the circumferential center to the circumferential outer side. On the outer peripheral surface of the side end portion, the portions on both sides in the circumferential direction across the center in the circumferential direction of the teeth are equally in contact with the inner peripheral surface of the yoke. For this reason, the flow of the magnetic flux with respect to the yoke in the outer peripheral surface of the outer diameter side end portion across the center in the circumferential direction of the teeth becomes the same, and the motor can be rotated smoothly. In addition, in the portion facing the teeth on the inner peripheral surface of the yoke, the portion facing the circumferential center of the outer diameter side end portion of the teeth is compared with the portion facing the circumferential both sides of the outer diameter side end portion of the teeth. The teeth are slightly distorted radially inward, but the teeth are locked in the circumferential direction on the inner peripheral surface of the yoke to prevent idling. The press-fitting allowance is the radial length of the portion that is press-fitted into the inner peripheral surface of the yoke at the outer diameter side end of the tooth.

  According to the fourth aspect of the present invention, when the stator core is press-fitted into the yoke, the inner peripheral surface of the yoke is slightly directed toward the concave portion formed in the circumferential central portion of the outer diameter side end portion of the tooth. Since the teeth are distorted, the teeth are locked in the circumferential direction on the inner peripheral surface of the yoke to prevent idling.

  According to the fifth aspect of the present invention, since the convex portion provided on the inner peripheral surface of the yoke is engaged with the concave portion formed on the outer diameter side end portion of the tooth, the stator core is reliably secured in the circumferential direction within the yoke. To prevent idling.

  According to the invention described in claim 6, the flanges formed on both sides in the circumferential direction of the outer diameter side end portion of the teeth have a circumferential width that is at least half of the circumferential width of the tooth, The width is at least half the circumferential width of the teeth. For this reason, the magnetic flux flowing through the teeth surely flows to the yoke. For example, even if a magnetic resistance such as a recess is formed at the center of the end portion on the outer diameter side of the tooth, no magnetic flux loss is caused. Further, since the idling torque of the stator core is increased by the flange portion, the stator core is securely fixed in the yoke.

  According to the seventh aspect of the present invention, since an annular magnetic member made of a magnetic material is provided on the outer portion of the stator core, a magnetic circuit can be formed outside the yoke by the annular magnetic member. By reducing the plate thickness, the portion other than the magnetic circuit can be reduced, and the stator and the motor can be reduced in size in the radial direction, thereby reducing the weight.

According to the eighth aspect of the present invention, it is possible to easily fix the skew by press-fitting the stator core into the inner peripheral surface of the yoke, and to reduce the detent torque.
According to invention of Claim 9, compared with the brushless motor provided with the stator which consists of the conventional inner core and outer core, there is little magnetic resistance between teeth and a yoke, and the flow of magnetic flux is smooth, Since the number of parts constituting the stator is reduced, the brushless motor is reduced in size and weight in the radial direction.

  According to the invention described in claim 10, compared with a conventional brushless motor having a stator composed of an inner core and an outer core, the brushless motor has a reduced magnetic resistance between the teeth and the yoke and a smooth magnetic flux flow. Opens and closes the valve. For this reason, the sound and vibration generated in the brushless motor are reduced, and the control of the valve becomes easy.

  According to the present invention, it is possible to provide a stator stator and a brushless motor that can be miniaturized and can be easily assembled.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a throttle valve device 1 mounted on an automobile engine to which a stator and a brushless motor according to the present invention are applied. The throttle valve device 1 is a device for controlling and adjusting the amount of air taken into the engine combustion chamber in order to suitably control the combustion state of the engine combustion chamber of the automobile, and the brushless motor is the air that flows into the engine combustion chamber. The valve provided in the intake pipe for controlling the speed or direction of the engine is opened and closed.

  The throttle valve device 1 includes a throttle body 3 in which an intake pipe 2 is formed, a throttle valve 4 as a valve provided in the intake pipe 2, a brushless motor 5 that drives the throttle valve 4, and driving of the brushless motor 5. And a control unit 6 for controlling. The intake pipe 2 is connected to an engine cylinder (not shown).

  The throttle valve 4 is rotatable about a rotating shaft 7 supported by the throttle body 3, and the intake pipe 2 is opened and closed by rotating around the rotating shaft 7 in the intake pipe 2. Adjust the amount of air that passes through and flows into the engine combustion chamber. One end of the rotary shaft 7 is connected to the output shaft 5a of the brushless motor 5 via a pinion 8 and a reduction gear 9, and the throttle valve 4 is fixed to the other end. The rotary shaft 7 is provided with a return spring 10, and this return spring 10 constantly urges the rotary shaft 7 so that the throttle valve 4 rotates in a direction to close the intake pipe 2.

  With this configuration, the brushless motor 5 is driven, the rotating shaft 7 rotates, and the throttle valve 4 rotates to open and close the intake pipe 2. When the brushless motor 5 is not driven so that the throttle valve 4 opens the intake pipe 2, the throttle valve 4 is biased by the return spring 10 to close the intake pipe 2.

  Further, the throttle body 3 is provided with an opening sensor 11 that outputs a detection signal corresponding to the opening of the throttle valve 4. The control unit 6 inputs signals such as a detection signal from the opening sensor 11, a depression amount of an accelerator pedal provided in the interior of the automobile, an engine speed, a vehicle speed, and the like, and controls the brushless motor 5 based on these signals. To do. That is, the control unit 6 controls the speed and direction of air that flows into the engine cylinder (not shown) connected to the intake pipe 2 in accordance with signals such as the accelerator pedal depression amount, the engine speed, and the vehicle speed. To do.

  Specifically, when the control unit 6 inputs signals, the control unit 6 sets the target opening of the throttle valve 4 based on these signals, and controls the brushless motor 5 so that the detection signal from the opening sensor 11 reaches the target opening. To drive. Then, when the opening degree of the throttle valve 4 reaches the target opening degree, the opening degree of the throttle valve 4 is maintained by maintaining the energization current amount of the brushless motor 5.

Next, the brushless motor 5 will be described. FIG. 2A is a cross-sectional view of the brushless motor 5. The brushless motor 5 includes a stator 20 and a rotor 30.
The stator 20 includes a stator core 23 having a ring-shaped annular portion 21 and a plurality of teeth 22 extending in a radial direction from the annular portion 21, and an outer diameter side end portion 22a of the teeth 22 fixed to an inner peripheral surface 24a. The outer peripheral surface 24 b includes a cylindrical yoke 24 made of a magnetic material that forms the outer peripheral surface 5 b of the brushless motor 5.

  Ten teeth 22 extend linearly in the radial direction with substantially the same circumferential width B (see FIG. 2B), and are arranged at equal intervals in the circumferential direction. In the annular portion 21, a thin portion 21 a is provided at a portion connecting the teeth 22. The thin portion 21a is provided to increase the magnetic resistance so as to reduce the leakage magnetic flux between the adjacent teeth 22. As shown in FIG. 3, the stator core 23 is a laminated core configured by laminating a plurality of core sheets 23 a formed by press punching a magnetic metal plate material. A winding (not shown) is wound around each tooth 22 via an insulator 25. The yoke 24 has a bottomed cylindrical shape.

  As shown in FIG. 2B, the outer diameter side end portion 22 a of the tooth 22 is provided with a flange portion 26 that extends to both sides in the circumferential direction with respect to the tooth 22. Each flange portion 26 has a radial width that is at least one half of the circumferential width B of the tooth 22, and a circumferential width that is at least one half of the circumferential width B of the tooth 22. Further, the outer peripheral surface 26a of each flange portion 26, that is, the outer peripheral surface 22b of the outer diameter side end portion 22a of the tooth 22, is a curved shape along the inner peripheral surface 24a of the yoke 24, and the flange portion 26 (outer diameter). The stator core 23 is fixed to the yoke 24 by the side end 22 a) being press-fitted and fixed to the inner peripheral surface 24 a of the yoke 24. That is, the outer peripheral surface 26a of each collar portion 26 extending on both sides in the circumferential direction at the outer diameter side end portion 22a of each tooth 22 is pressed against the inner peripheral surface 24a, so that the outer peripheral surface 22b of each tooth 22 is the circumference of the tooth 22. Only the direction width B is surely pressed against the inner peripheral surface 24a, and a surface through which the magnetic flux flows is secured.

  Further, a concave portion 27 extending in the axial direction is formed between the circumferential center portion of the outer peripheral surface 22b of the outer diameter side end portion 22a, that is, between the flange portions 26. Each concave portion 27 has an opening on the outer side in the radial direction, and has a substantially trapezoidal shape such that the sides facing each other in the circumferential direction are separated from each other toward the outer side in the radial direction.

  Further, the inner peripheral surface 24a of the yoke 24 is provided with a convex portion 28 that protrudes from the inner peripheral surface 24a and extends in the axial direction at a position corresponding to each tooth 22 and is engaged with the concave portion 27. Yes. The convex portion 28 may be formed by newly providing a protrusion on the inner peripheral surface 24a, or may be formed by deforming the yoke 24 inward.

  In the stator 20 having such a configuration, first, the stator core 23 is configured by laminating a plurality of core sheets 23a in the axial direction. Next, an insulator 25 is attached to the stator core 23, and a winding is wound around each tooth 22. Then, the concave portion 27 of the stator core 23 and the convex portion 28 of the yoke 24 are aligned, and the stator core 23 is press-fitted into the yoke 24 so that the concave portion 27 is fitted to the convex portion 28. At this time, the stator core 23 is press-fitted into the yoke 24, whereby the convex portion 28 is fitted along the concave portion 27, and the stator core 23 is locked in the circumferential direction with respect to the yoke 24. The stator core 23 is fixed in a state where the outer peripheral surface 26a of the flange portion 26 (the outer peripheral surface 22b of the teeth 22) is in pressure contact with the inner peripheral surface 24a of the yoke 24, and does not cause rattling in the circumferential direction.

  On the other hand, as shown in FIG. 2A, the rotor 30 is rotatably disposed inside the stator 20 and is generated in the stator 20 based on an output signal from the control unit 6 (see FIG. 1). It is rotated by a rotating magnetic field. The rotor 30 has a plurality of magnets 31 having different polarities in the circumferential direction fixed to the outer peripheral surface thereof, and is rotatable about a rotating shaft 32 having the output shaft 5a (see FIG. 1) at its end. ing.

Next, characteristic effects of the above embodiment will be described below.
(1) Since the stator 20 is configured by fixing the stator core 23 to the yoke 24, the stator 20 is reduced in size compared to the case where the stator is configured to include an inner core, an outer core, and a yoke. Moreover, since the number of parts which comprise the stator 20 is reduced, cost reduction can be aimed at. Moreover, since the stator 20 can be formed by fixing the stator core 23 to the inner peripheral surface 24a of the yoke 24, it can be easily assembled. Therefore, the brushless motor 5 can be miniaturized and assembled easily.

  (2) Since the outer peripheral surface 22b of the outer diameter side end portion 22a of the tooth 22 has a curved shape along the inner peripheral surface 24a of the yoke 24, the outer peripheral surface 22b of the outer diameter side end portion 22a of the tooth 22 is the yoke. 24, the outer peripheral surface 22b of the outer diameter side end 22a of the tooth 22 becomes a magnetic passage surface. For this reason, the magnetic flux efficiently flows from the teeth 22 to the yoke 24, and the plate thickness of the yoke 24 can be reduced compared to the case where there is a magnetic resistance in this portion, and the stator 20 can be downsized.

  (3) Since the convex portion 28 provided on the inner peripheral surface 24 a of the yoke 24 is engaged with the concave portion 27 formed on the outer diameter side end portion 22 a of the tooth 22, the stator core 23 is arranged in the circumferential direction within the yoke 24. Engagement is ensured and idling is prevented.

  (4) The flanges 26 formed on both sides in the circumferential direction of the outer diameter side end 22a of the tooth 22 have a circumferential width that is at least half the circumferential width B of the tooth 22, and the radial width is the teeth. It is set to 1/2 or more of the circumferential width B of 22. For this reason, the magnetic flux flowing through the teeth 22 surely flows into the yoke 24. For example, even if a magnetic part such as a recess is formed at the center of the outer diameter side end 22a of the tooth 22, no magnetic flux loss is caused. Further, since the idling torque of the stator core 23 is increased by the flange portion 26, the stator core 23 is securely fixed in the yoke 24.

  (5) Compared to a conventional brushless motor having a stator composed of an inner core and an outer core, the throttle valve 4 is controlled by the brushless motor 5 having a small magnetic resistance between the teeth 22 and the yoke 24 and a smooth flow of magnetic flux. Opened and closed. For this reason, the sound and vibration generated in the brushless motor 5 are reduced, and the control of the throttle valve 4 is facilitated.

In addition, you may change embodiment of this invention as follows.
In the above embodiment, the outer peripheral surface 22b of the outer diameter side end portion 22a of the tooth 22 (that is, the outer peripheral surface 26a of the flange portion 26) has a curved shape along the inner peripheral surface 24a of the yoke 24. However, the outer peripheral surface 22b (26a) is not limited to this shape. For example, in the said embodiment, it may replace with the teeth 22 and may use the teeth 40 shown to Fig.4 (a). In this case, it is assumed that the projections 28 are not provided on the yoke 24 before the stator is press-fitted. As shown in FIG. 4A, the outer diameter side end portion 41 of the tooth 40 gradually increases the press-fitting allowance with respect to the inner peripheral surface 24 a of the yoke 24 from the circumferential center of the tooth 40 toward the circumferential outer side. Is set to The press-fitting allowance is the radial length of the portion that is press-fitted into the inner peripheral surface 24a of the yoke 24 at the outer diameter side end of the tooth 40. Further, a recess 42 is formed in the central portion in the circumferential direction of the outer peripheral surface 41 a of the outer diameter side end 41. If comprised in this way, in the outer peripheral surface 41a of the outer-diameter side edge part 41 of the teeth 40, the part of the circumferential direction both sides will contact | abut to the inner peripheral surface 24a of the yoke 24 equally on both sides of the circumferential center of the teeth 40. .

  That is, with this configuration, when the stator core is press-fitted into the yoke 24, the outer peripheral side end 41 has a circumferential center of the teeth 40 even if the inner peripheral surface 24 a of the yoke 24 is not a perfect circle. The portions on both sides in the circumferential direction are in contact with the inner peripheral surface 24a of the yoke 24 equally. For this reason, the flow of magnetic flux to the yoke 24 on the outer peripheral surface 41a of the outer diameter side end 41 across the circumferential center of the teeth 40 is the same, and the magnetic flux flows from the teeth 40 to both sides in the circumferential direction. Don't bias. Therefore, the brushless motor can be smoothly rotated.

  Further, in the portion of the inner peripheral surface 24 a of the yoke 24 facing the teeth 40, the center in the circumferential direction of the outer diameter side end portion 41 of the teeth 40, that is, the portion facing the recess 42 is the outer diameter side end portion 41 of the tooth 40. Compared to the portions facing both sides in the circumferential direction, the inner side is slightly distorted in the radial direction. This is because the portion of the inner peripheral surface 24 a of the yoke 24 that faces both sides in the circumferential direction of the outer diameter side end portion 41 (the portion where the press-fitting allowance is large) is radial along the outer peripheral surface 41 a of the outer diameter side end portion 41. This is because it is slightly deformed outward. For this reason, the teeth 40 are locked in the circumferential direction on the inner peripheral surface 24a of the yoke 24 to prevent idling.

  In the above embodiment, as shown in FIG. 5, a cylindrical annular magnetic member 50 made of a magnetic material may be provided on the outer surface of the yoke 24 on the outer side where the stator core 23 is press-fitted. . With this configuration, since the magnetic circuit can be formed outside the yoke 24 by the annular magnetic member 50, the portion other than the magnetic circuit can be reduced by reducing the thickness of the yoke 24, and the stator 20 and the brushless motor. 5 can be reduced in size in the radial direction to reduce the weight. The annular magnetic member 50 may be a C-ring.

  In the above embodiment, the stator core 23 may have a skewed slot. In this case, it is possible to easily fix the skew by press-fitting the stator core 23 into the inner peripheral surface 24a of the yoke 24, and to reduce the detent torque.

  In the above embodiment, the concave portion 27 is formed in the central portion in the circumferential direction of each tooth 22, and the convex portion 28 is provided at a position corresponding to each concave portion 27 on the inner peripheral surface 24a of the yoke 24. The number, shape, and position of the corresponding convex portions 28 may be changed as appropriate.

  -In above-mentioned embodiment, although the recessed part 27 was provided in each teeth 22, the recessed part 27 does not necessarily need to be provided. Even if the recess 27 is not provided, the outer diameter side end 22 a of the tooth 22 is press-fitted into the inner peripheral surface 24 a of the yoke 24 and fixed. In that case, the convex portion 28 may not be provided on the yoke 24.

  -You may change suitably the structure of the brushless motor 5 of the said embodiment other than the above. For example, although the teeth 22 are arranged at equal intervals on the stator core 23, the arrangement may not be equal intervals. Further, the number of teeth 22 may be other than ten.

  In the above embodiment, the case where the stator 20 and the brushless motor 5 are applied to the throttle valve device 1 has been described. However, the stator 20 and the brushless motor 5 may be applied to devices other than the throttle valve device 1.

The schematic block diagram of a throttle valve apparatus. (A) is sectional drawing of a brushless motor. (B) is the elements on larger scale of (a). An axial direction sectional view of a brushless motor. (A), (b) is sectional drawing explaining the teeth of a modification. Sectional drawing explaining the stator of a modification.

Explanation of symbols

  2 ... intake pipe, 4 ... throttle valve as valve, 5 ... brushless motor, 5b ... outer peripheral surface of motor, 20 ... stator, 21 ... annular part, 22, 40 ... teeth, 22a, 41 ... outer diameter side end of teeth Part, 22b, 41a ... outer peripheral surface of teeth, 23 ... stator core, 24 ... yoke, 24a ... inner peripheral surface of yoke, 24b ... outer peripheral surface of yoke, 26 ... collar, 26a ... outer peripheral surface of collar, 27, 42 ... concave portion, 28 ... convex portion, 30 ... rotor, 50 ... annular magnetic member, B ... circumferential width of teeth.

Claims (10)

A stator core comprising a ring-shaped annular portion and a plurality of teeth extending radially from the annular portion;
A cylindrical yoke made of a magnetic material whose outer diameter side end of the tooth is fixed to the inner peripheral surface and whose outer peripheral surface forms the outer peripheral surface of the motor;
A stator comprising: The stator according to claim 1,
The outer peripheral surface of the outer diameter side end of the teeth is a curved shape along the inner peripheral surface of the yoke,
A stator characterized in that the stator core is fixed to the yoke by press-fitting and fixing the outer peripheral surface of the outer diameter side end portion to the inner peripheral surface of the yoke. The stator according to claim 1,
The stator is characterized in that the outer diameter side end portion of the teeth is set so that a press-fitting allowance with respect to the inner peripheral surface of the yoke gradually increases from the circumferential center line of the teeth toward the outer side in the circumferential direction. . In the stator according to any one of claims 1 to 3,
A concave portion extending in the axial direction is formed in a central portion in the circumferential direction of the outer diameter side end portion of the tooth. The stator according to claim 4, wherein
The stator is characterized in that the inner peripheral surface of the yoke is provided with a convex portion that protrudes from the inner peripheral surface and extends in the axial direction and engages with the concave portion. In the stator according to any one of claims 1 to 5,
At the outer diameter side end portion of the teeth, the radial width is at least one half of the circumferential width of the teeth and the circumferential width of the teeth is extended to both sides in the circumferential direction with respect to the teeth. A stator having a flange portion that is at least half the circumferential width, and the stator core is fixed to the inner peripheral surface of the yoke by the flange portion. The stator according to any one of claims 1 to 6,
The stator further comprising a cylindrical annular magnetic member made of a magnetic material at an outer portion of the yoke on the outer side where the stator core is press-fitted. The stator according to claim 1,
The stator having a skewed slot. The stator according to any one of claims 1 to 8,
A rotor rotatably disposed inside the stator and rotated by a rotating magnetic field generated in the stator;
A brushless motor characterized by comprising: The brushless motor according to claim 9,
The brushless motor opens and closes a valve provided in an intake pipe that controls the speed or direction of air flowing into the engine combustion chamber.

Images