JP2007043832A - Manufacturing method of stator, brushless motor and yoke - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stator capable of attaining downsizing, while ensuring a magnetic path, as well as preventing idle motion of a stator core. <P>SOLUTION: This stator 20 includes a stator core 23 equipped with an annular toroidal section 21, and a plurality of teeth segments 22, extending to the radially outward side in the radial direction from the toroidal section 21; and a yoke 25 having a tubular section 24 fixing the stator core 23 on the inner periphery surface. V-shaped recesses 26, when viewed in the axial direction, are formed on the outer edges of the teeth segments 22, and protrusions 28 in the shape of V, when viewed in the axial direction, protruding inward in the radial direction are formed on the yoke 25. Both the sides 28a of the protrusions 28 are pressed fit into both the sides 26a of the protrusions 26, thus fixing the stator core 23 onto the inner periphery surface of the yoke 25. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a stator, a brushless motor, and a yoke 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, in the said conventional structure, since the yoke was formed with iron of a magnetic body, the function of forming a magnetic circuit with the outer core overlapped, and there was a waste in terms of the structure. Thus, in order to reduce the number of members and reduce the size of the motor, a configuration in which the outer core is omitted and the inner core is directly press-fitted into the yoke is conceivable. In this case, a structure for fixing the inner core in the yoke is required.

  Therefore, it is conceivable to make a concave-convex fit between the inner peripheral surface of the yoke and the outer peripheral surface of the inner core, but by using the concave-convex shape, the yoke and inner core are pressed against each other on a curved surface without irregularities. As a result, the magnetic resistance of the fitting portion increases.

  Further, for example, when a concave portion is formed on the inner peripheral surface of the yoke and a convex portion formed on the outer peripheral surface of the inner core is fitted, the concave portion is formed on the yoke, thereby reducing the thickness of this portion and reducing the magnetic flux. The flow is obstructed. However, if the thickness of the yoke is sufficient to secure the magnetic path in the portion where the recess is formed, the yoke will be enlarged.

Further, for example, when the inner core is fixed by being press-fitted into the yoke without providing a concave portion or a convex portion, the inner core is likely to idle in the circumferential direction within the yoke.
SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a stator, a brushless motor, and a yoke capable of realizing downsizing while ensuring a magnetic path and preventing idling of the stator core. It is to provide a manufacturing method.

  In order to solve the above-mentioned problem, the invention according to claim 1 is a stator core including a ring-shaped annular portion and a plurality of teeth extending radially from the annular portion, and a cylinder that fixes the stator core on an inner peripheral surface. A stator having a yoke, and a V-shaped recess as viewed in the axial direction is formed at an outer end portion of the tooth, and a V-shape as viewed in the axial direction protrudes radially inward from the yoke. The convex portion is formed, and both sides of the convex portion are press-fitted into both sides of the concave portion, so that the stator core is fixed to the inner peripheral surface of the yoke.

According to a second aspect of the present invention, in the stator according to the first aspect, the both side intersections of the concave portion and the convex portion, which are V-shaped when viewed in the axial direction, are formed at a circumferential central portion of the teeth. .
According to a third aspect of the present invention, in the stator of the second aspect, both sides of the convex portion formed on the yoke are gradually thickened from the circumferential center to the circumferential outer side.

According to a fourth aspect of the present invention, in the stator according to any one of the first to third aspects, the concave and convex portions are formed at equal intervals in the circumferential direction.
According to a fifth aspect of the present invention, in the stator according to any one of the first to fourth aspects, the concave portion and the convex portion are formed for all teeth.

  According to a sixth aspect of the present invention, the stator according to any one of the first to fifth 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. And a rotor.

  The invention described in claim 7 includes a cylindrical portion that fixes a stator core having a ring-shaped annular portion and a plurality of teeth extending in a radial direction from the annular portion on an inner peripheral surface, and is formed in the cylindrical portion. The stator core is fixed to the inner peripheral surface by press-fitting both sides of the V-shaped concave portion formed on the outer end portion of the tooth to both sides of the V-shaped convex portion viewed in the axial direction. A method of manufacturing a yoke, wherein a mandrel having a molding portion formed in a V shape in an axial direction is formed in a state before the projection is formed with respect to the yoke in order to form the projection. Inserting into the workpiece, pressurizing the die from the outer peripheral side of the cylindrical portion of the workpiece toward the molding portion of the mandrel, and moving the meat of adjacent portions adjacent to both sides in the circumferential direction of the convex portion with the die Thus, both sides of the convex portion are formed.

  According to an eighth aspect of the present invention, in the yoke manufacturing method according to the seventh aspect, the die rotates relative to the workpiece and continuously pressurizes the cylindrical portion along the circumferential direction of the cylindrical portion. Thus, the convex portion is formed to protrude.

(Function)
According to the first aspect of the present invention, both sides of the V-shaped convex portion viewed in the axial direction are press-fitted into both sides of the concave portion viewed in the axial direction, so that the stator core is fitted to the inner peripheral surface of the yoke. It is fixed. In this way, the concave portion and the convex portion are V-shaped when viewed in the axial direction, and the contact surface between the two is substantially flat and the contact width in the circumferential direction increases. It is possible to prevent an increase in magnetoresistance during the period. For this reason, it is possible to reduce the thickness of the yoke while securing a magnetic path as compared with the case where there is a magnetic resistance at the fitting portion between the yoke and the stator core, and the entire yoke can be downsized in the radial direction. it can. Further, since the concave portion formed at the outer end portion of the teeth is locked in the circumferential direction by the convex portion formed on the inner peripheral surface of the yoke, idling in the yoke of the stator core can be prevented.

  According to the second aspect of the present invention, the intersecting portions on both sides of the V-shaped concave portion and the convex portion in the axial direction are formed at the center portion in the circumferential direction of the tooth, so that the tooth and the yoke are formed at the outer end portion of the tooth. The magnetic flux between the two is symmetrical about the center in the circumferential direction. For this reason, the flow of the magnetic flux in the fitting part of the concave part and the convex part becomes smooth, and an increase in the magnetic resistance between them is prevented.

  According to the invention described in claim 3, since the thickness of both sides of the convex portion formed on the yoke is gradually increased from the circumferential central portion toward the circumferential outer side, the convex portion has a magnetic flow. The shape is such that the magnetic path is secured toward the portions on both sides in the circumferential direction in which the number of points increases. For this reason, increase of the magnetic resistance in the fitting part of a recessed part and a convex part is prevented suitably.

  According to the fourth aspect of the present invention, since the concave portions and the convex portions are formed at equal intervals in the circumferential direction, transfer of magnetic flux between the yoke and the stator core is uniform in the circumferential direction, and the inner peripheral surface of the stator core. The rotation of the rotor arranged in the is stabilized.

  According to the fifth aspect of the present invention, since the concave portion and the convex portion are formed for all the teeth, magnetic flux is efficiently transferred between the yoke and the stator core, and the inner peripheral surface of the stator core is provided. The arranged rotor is rotated with high efficiency.

  According to the invention described in claim 6, compared with a brushless motor having a stator composed of a conventional inner core and outer core, there is less magnetic resistance between the teeth and the 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 seventh aspect of the present invention, when the convex portion is formed on the yoke, the protruding portions are formed because the flesh of adjacent portions adjacent to both sides in the circumferential direction of the convex portion is collected to form both sides of the convex portion. However, it can be formed thick. Moreover, since the convex part is formed by pressurizing the workpiece before the convex part is formed from the outer diameter side, a highly accurate dimension can be secured, and the stator core can be easily press-fitted into the yoke. It becomes like this. Further, the portions near the adjacent portions on both sides of the convex portion where the magnetic flow increases, the thickness can be easily moved from the adjacent portions, and the thickness can be increased and the magnetic resistance does not occur.

  According to the invention described in claim 8, when the die rotates relative to the workpiece and pressurizes the cylindrical portion, a convex portion having a high dimensional accuracy is formed on the cylindrical portion.

  According to the present invention, it is possible to achieve downsizing while securing a magnetic path and to prevent idling of the stator core.

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, when the brushless motor 5 is driven, the rotary shaft 7 rotates, so that the throttle valve 4 opens the intake pipe 2. When the brushless motor 5 is not driven, the rotary shaft 7 is biased by the return spring 10 so that the throttle valve 4 closes 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 a magnetic body having a cylindrical portion 24 that fixes the stator core 23 on the inner peripheral surface. The bottomed cylindrical yoke 25 is provided.

  Ten teeth 22 are linearly extended in the radial direction with substantially the same circumferential width (see FIG. 2B), and ten teeth 22 are arranged at equal intervals in the circumferential direction. On the outer end portion of the tooth 22, a concave portion 26 is formed which is formed of both sides 26 a opened in a V shape when viewed in the axial 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 I. The yoke 25 has a bottomed cylindrical shape.

  As shown in FIG. 2B, the cylindrical portion 24 of the yoke 25 is formed with a convex portion 28 composed of both sides 28a formed in a V-shape as viewed in the axial direction and projecting radially inward. The thickness W of both sides 28a of the convex portion 28 is gradually increased from the center in the circumferential direction toward the outer side in the circumferential direction. The stator core 23 is fixed to the inner peripheral surface of the yoke 25 (cylindrical portion 24) by press-fitting the concave portion 26 to the convex portion 28. The crossing portions on both sides of the concave portions 26 and the convex portions 28 that are V-shaped when viewed in the axial direction are formed at the center in the circumferential direction of the teeth 22. Further, the concave portion 26 of the stator core 23 and the convex portion 28 of the yoke 25 are formed for all the teeth 22.

  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, a method for manufacturing the brushless motor 5 will be described.
As shown in FIG. 3, the stator 20 having the above-described configuration is configured by first stacking a plurality of core sheets 23 a in the axial direction. Next, the insulator I is mounted on the stator core 23, and a winding is wound around each tooth 22.

  Thereafter, as shown in FIG. 2A, the concave portion 26 of the stator core 23 and the convex portion 28 of the yoke 25 are aligned, and the yoke 28 is fitted so that both sides 28a of the convex portion 28 are fitted to both sides 26a of the concave portion 26. The stator core 23 is press-fitted into the inner peripheral surface of 25. At this time, the stator core 23 is press-fitted into the yoke 25, so that both sides 28 a of the convex portion 28 are fitted along both sides 26 a of the concave portion 26, and the stator core 23 is locked to the yoke 25 in the circumferential direction. .

Here, a manufacturing method of the yoke 25 will be described.
First, the processing apparatus 100 for manufacturing the yoke 25 will be described. The processing apparatus 100 shown in FIG. 5 is for manufacturing the yoke 25 by performing post-processing on the workpiece 40 after drawing shown in FIG. The workpiece 40 is in a state before the convex portion 28 is formed with respect to the yoke 25 which is a finished product, and has a bottomed cylindrical shape in which a cylindrical portion 41, a bottom portion 42, and a bearing concave portion 43 are integrally formed. .

  As shown in FIG. 5, the processing apparatus 100 includes a mandrel 101 inserted into the work 40 after drawing shown in FIG. 4, a front restraint block 102 that fixes the work 40 after insertion of the mandrel 101 from both sides in the axial direction, and The rear restraint block 103 and two dies 104 and 105 that pressurize the work 40 from the outside in the radial direction of the work 40 are provided.

  As shown in FIG. 5, the mandrel 101 includes a cylindrical portion 101a and a protruding portion 101b provided at the center of the tip surface of the cylindrical portion 101a. The outer diameter of the cylindrical portion 101a is substantially the inner diameter of the workpiece 40, and as shown in FIG. 6, forming concave portions 101c as a plurality of forming portions are formed on the outer peripheral surface. The molding concave portion 101c is formed at a location corresponding to the convex portion 28 in the circumferential direction and at a portion corresponding to the cylindrical portion 24 of the yoke 25 in the axial direction. The protrusion 101b has a shape corresponding to the inner peripheral surface of the bearing recess 43 so that the outer peripheral surface of the protrusion 101b and the inner peripheral surface of the bearing recess 43 are in contact with each other.

  As shown in FIG. 5, the front restraint block 102 restrains the workpiece 40 from the bearing recess 43 side of the workpiece 40. The front restraint block 102 includes a contact surface 102 a that contacts the bottom 42 of the workpiece 40. A holding recess 102b is formed at the center of the contact surface 102a, and the bearing recess 43 of the workpiece 40 is fitted into the holding recess 102b. The rear restraint block 103 restrains the work 40 from the opening end side of the work 40. The rear restraint block 103 includes a contact surface 103 a that contacts the open end of the workpiece 40.

  The two dies 104 and 105 are disposed apart from the outer peripheral surface of the cylindrical portion 24, and can come into contact with and separate from the cylindrical portion 24 along the radial direction. The dies 104 and 105 are for forming the convex portion 28 of the yoke 25, and the axial length thereof is substantially equal to the axial length of the convex portion 28.

  In manufacturing the yoke 25 by the processing apparatus 100 configured as described above, first, the mandrel 101 is inserted into the work 40 formed by drawing. At this time, the protrusion 101 b of the mandrel 101 is inserted into the bearing recess 43 of the workpiece 40 and is engaged with the bearing recess 43 by bringing the outer peripheral surface thereof into contact with the inner peripheral surface of the bearing recess 43.

  Next, the workpiece 40 is fixed so as not to move in the axial direction by the front restraint block 102 and the rear restraint block 103. Specifically, the front restraint block 102 and the rear restraint block 103 sandwich the work 40 from both sides in the axial direction of the work 40, and press the work 40 in the axial direction toward the front restraint block 102 and the rear restraint block 103. At this time, the front restraint block 102 fits the bearing recess 43 of the workpiece 40 into the holding recess 102b and makes the contact surface 102a contact the bottom 42.

  At the same time, the rear restraint block 103 abuts the abutment surface 103 a against the open end of the workpiece 40. As a result, the workpiece 40 is fixed so as not to move in the axial direction, and the axial length is kept constant even during machining described later.

  Thereafter, the dies 104 and 105 are brought into contact with the cylindrical portion 24 from the outer peripheral side of the cylindrical portion 24 and are rotated while pressurizing the cylindrical portion 24 toward the molding concave portion 101 c of the mandrel 101. At this time, in the material constituting the cylindrical portion 24, a part of the material pressed by the dies 104 and 105 moves to escape to the molding recess 101 c, so that it is closer to the adjacent portion 27. A V-shaped convex portion 28 having both sides 28a that are thick (becomes gradually thicker toward the outside in the circumferential direction) is formed.

  Then, after the dies 104 and 105 are separated from the yoke 25 and the restraint by the front restraint block 102 and the rear restraint block 103 is released, the mandrel 101 is pulled out from the opening of the yoke 25 and the finished yoke 25 is taken out. It is.

Next, characteristic effects of the above embodiment will be described below.
(1) The stator core 23 is fixed to the inner peripheral surface of the yoke 25 by press-fitting both sides 28a of the V-shaped convex portion 28 into the V-shaped concave portion 26. In this way, the concave portion 26 and the convex portion 28 are V-shaped in the axial direction, the contact surfaces of both are substantially flat, and the contact width in the circumferential direction increases. An increase in magnetic resistance between the convex portions 28 can be prevented. Therefore, it is possible to reduce the thickness of the yoke 25 while securing a magnetic path as compared with the case where the fitting portion between the yoke 25 and the stator core 23 has a magnetic resistance, and the entire yoke 25 is reduced in the radial direction. Can be

  (2) Since the concave portion 26 formed on the outer end portion of the tooth 22 is locked in the circumferential direction by the convex portion 28 formed on the inner peripheral surface of the yoke 25, the idling of the stator core 23 in the yoke 25 is prevented. Can do.

  (3) Since the intersecting portions of both sides of the concave portion 26 and the convex portion 28 that are V-shaped when viewed in the axial direction are formed at the center in the circumferential direction of the tooth 22, the teeth 22 and the yoke 25 The magnetic flux between the two is symmetrical about the center in the circumferential direction. For this reason, the flow of the magnetic flux in the fitting part of the recessed part 26 and the convex part 28 becomes smooth, and the increase in magnetic resistance between both is prevented.

  (4) Since the thickness W of both sides 28a of the convex portion 28 formed on the yoke 25 is gradually increased from the circumferential central portion toward the outer circumferential direction, the convex portion 28 increases the magnetic flow. The magnetic path is secured toward both sides in the circumferential direction. For this reason, increase in the magnetic resistance in the fitting part of the recessed part 26 and the convex part 28 is prevented suitably.

  (5) Since the concave portions 26 and the convex portions 28 are formed at equal intervals in the circumferential direction, the transfer of magnetic flux between the yoke 25 and the stator core 23 is uniform in the circumferential direction, and is disposed on the inner circumferential surface of the stator core 23. The rotation of the rotor 30 is stabilized.

  (6) Since the concave portions 26 and the convex portions 28 are formed for all the teeth 22, the magnetic flux is efficiently transferred between the yoke 25 and the stator core 23, and disposed on the inner peripheral surface of the stator core 23. The rotor 30 is rotated with high efficiency.

  (7) 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 25 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.

  (8) Since the convex portions 28 are formed by collecting the meat of the adjacent portions 27 adjacent to the yoke 25 on both sides in the circumferential direction of the convex portions 28, they can be formed thick even though they are protruding portions. Moreover, since the convex part 28 is formed by pressurizing the workpiece 40 before the convex part 28 is formed from the outer diameter side, a highly accurate dimension can be secured, and the stator core 23 can be easily placed in the yoke 25. Can be press-fitted. Further, the portion close to the adjacent portion 27 on both sides 28a of the convex portion 28 where the magnetic flow increases, the thickness can be easily moved from the adjacent portion 27, the thickness can be increased, and the magnetic resistance does not occur.

(9) When the dies 104 and 105 rotate relative to the workpiece 40 and pressurize the cylindrical portion 24, the cylindrical portion 24 is formed with a convex portion 28 having high dimensional accuracy.
In addition, you may change embodiment of this invention as follows.

  -In above-mentioned embodiment, although the convex part 28 formed in the yoke 25 shall become thick gradually toward the circumferential direction outer side from the circumferential direction center part, the shape of the convex part 28 is not limited to this. . For example, the thickness of the convex portion 28 may be uniform in the circumferential direction.

  In the above embodiment, the concave portions 26 and the convex portions 28 are provided in the portions corresponding to all the teeth 22, but the concave portions 26 and the convex portions 28 are not necessarily provided for all the teeth 22. For example, you may provide only with respect to one tooth. Moreover, even if it is not provided for all the teeth 22, if concave portions and convex portions are provided at equal intervals in the circumferential direction, the transfer of magnetic flux between the yoke and the stator core becomes uniform in the circumferential direction, and the inner peripheral surface of the stator core The effect that the rotation of the rotor arranged in the can be stabilized can be obtained.

  -In above-mentioned embodiment, although the recessed part 26 and the convex part 28 shall be provided in the circumferential direction center part of the teeth 22, the recessed part 26 and the convex part 28 do not necessarily need to be provided in the circumferential direction center part of the teeth 22. Also good. It is good also as a shape where the recessed part and the convex part were biased to one side in the circumferential direction.

  -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 not be 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 technical idea that can be grasped from the above embodiment will be described below.
(B) The brushless motor according to claim 6, 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.

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. Sectional drawing which shows the workpiece | work formed by drawing. Sectional drawing of a processing apparatus. Sectional drawing of a mandrel.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 5 ... Brushless motor, 20 ... Stator, 21 ... Annular part, 22 ... Teeth, 23 ... Stator core, 24 ... Cylindrical part, 25 ... Yoke, 26 ... Recessed part, 26a ... Both sides of a recessed part, 27 ... Adjacent part, 28 ... Convex part 28a ... both sides of the convex part, 30 ... rotor, 40 ... work, 101 ... mandrel, 101c ... molding concave part as a molding part, 104, 105 ... die.

Claims (8)

A stator core comprising a ring-shaped annular portion and a plurality of teeth extending radially outward from the annular portion;
A yoke having a cylindrical portion for fixing the stator core on the inner peripheral surface;
A stator with
An axially-viewed V-shaped recess is formed at the outer end portion of the tooth, and an axially-viewed V-shaped projecting portion protruding radially inward is formed on the yoke. The stator core is fixed to the inner peripheral surface of the yoke by being press-fitted into both sides of the recess. The stator according to claim 1,
The stator is characterized in that a crossing portion on both sides of the concave portion and the convex portion, which is V-shaped when viewed in the axial direction, is formed at a circumferential center portion of the teeth. The stator according to claim 2, wherein
The stator is characterized in that both sides of the convex portion formed on the yoke are gradually thickened from the center in the circumferential direction toward the outer side in the circumferential direction. In the stator according to any one of claims 1 to 3,
The said recessed part and convex part are formed in the circumferential direction at equal intervals, The stator characterized by the above-mentioned. In the stator according to any one of claims 1 to 4,
The said recessed part and convex part are formed with respect to all the teeth, The stator characterized by the above-mentioned. The stator according to any one of claims 1 to 5,
A rotor rotatably disposed inside the stator and rotated by a rotating magnetic field generated in the stator;
A brushless motor characterized by comprising: A cylindrical portion that fixes a stator core having a ring-shaped annular portion and a plurality of teeth extending in a radial direction from the annular portion on an inner peripheral surface;
The stator core is formed by press-fitting both sides of a V-shaped concave portion formed in the outer end portion of the tooth into both sides of a V-shaped convex portion formed in the cylindrical portion. A method of manufacturing a yoke to be fixed to an inner peripheral surface,
In order to form the convex portion, a mandrel having a molding portion formed in a V shape in the axial direction is inserted into the workpiece in a state before the convex portion is formed with respect to the yoke,
By pressing the die from the outer peripheral side of the cylindrical portion of the workpiece toward the molding portion of the mandrel, the convex portion is moved by moving the meat of the adjacent portions adjacent to both sides in the circumferential direction of the convex portion with the die. A method for manufacturing a yoke, characterized in that both sides are formed. In the manufacturing method of the yoke according to claim 7,
The method for producing a yoke according to claim 1, wherein the die is rotated relative to the work and pressurizes the cylindrical portion continuously along a circumferential direction of the cylindrical portion to project the convex portion.

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