JP6824348B2 - Manufacturing method of single-phase brushless motor, single-phase brushless motor, vacuum cleaner equipped with single-phase brushless motor, and manufacturing method of vacuum cleaner - Google Patents

Description

The present invention relates to a method for producing a single-phase brushless motor and the single-phase brushless motor.

As a conventional single-phase brushless motor, a rotor having a plurality of magnetic poles and a stator arranged with a gap from the rotor and having the same number of salient poles as the plurality of magnetic poles of the rotor are provided, and each of the salient poles is a rotor. An outer rotor type single-phase brushless motor having a groove provided on the salient pole surface facing the magnet at a position closer to the edge from the center in the circumferential direction has been proposed.

Japanese Unexamined Patent Publication No. 2012-029515

The conventional single-phase brushless motor is configured as described above, and causes start-up instability by providing a groove on the salient pole surface facing the rotor at a position closer to the end from the center in the circumferential direction of the salient pole. It is possible to lower the peak value of the cogging torque without doing so, but there is almost no effect of shifting the point where the cogging torque becomes zero from the center of the salient pole, and there is a problem that it is difficult to obtain a sufficient starting torque. there were. Further, if the groove is provided at a position closer to the end from the center of the circumferential direction of the salient pole surface, the magnetic flux in the peripheral portion where the groove is provided is disturbed, the magnetic flux density is locally increased, and iron loss is caused. Increase.
The present invention is to solve the above-mentioned problems to obtain a single-phase brushless motor capable of reducing cogging torque and obtaining a sufficient starting torque, and to provide a method for manufacturing a single-phase brushless motor. The purpose.

In the single-phase brushless motor according to the present invention,
A single-phase brushless motor having a rotor and a stator,
The rotor has a cylindrical shape and has a plurality of magnetic poles formed by permanent magnets.
The stator has a stator core and a coil.
The stator core has a yoke and a plurality of magnetic pole teeth.
The magnetic pole tooth has one end and the other end, and is formed at the one end by connecting an arc plane centered on the center line of the rotor and connecting the arc plane to the connecting portion. It has a surface, and the adjacent surface is extended at the same position as the tangent plane of the arc surface at the connection portion between the arc surface and the adjacent surface or with the same curvature as the arc surface from the tangent plane. It is a plane formed so as to be located far from the virtual arc plane.
The coil is wound around the magnetic pole teeth,
The arc surface and the adjacent surface are arranged to face the rotor with a gap in the radial direction of the rotor.
The other end is magnetically coupled to the yoke.

The method for manufacturing a single-phase brushless motor according to the present invention includes a step of bringing the arc surface of the magnetic pole teeth into contact with a cylindrical assembly jig to align the magnetic pole teeth.

In the method for manufacturing a single-phase brushless motor according to the present invention, a step of manufacturing an insulating member assembly having a plurality of insulating members, a step of causing the insulating member to hold the magnetic pole teeth, and a cylindrical assembly jig. It has a step of aligning the magnetic pole teeth by bringing the arcuate surfaces of the magnetic pole teeth into contact with each other.

The single-phase brushless motor according to the present invention
The magnetic pole tooth has one end and the other end, and at the one end, an arc surface centered on the center line of the rotor and an adjacent surface formed by connecting to the arc surface are provided. The adjacent surface has the same position as the tangent plane of the arc surface at the connection portion between the arc surface and the adjacent surface, or a virtual arc surface extended from the tangent plane with the same curvature as the arc surface. Because it is a plane formed so as to be located far from
It is possible to obtain a single-phase brushless motor that can reduce the cogging torque and obtain a sufficient starting torque.

Since the method for manufacturing a single-phase brushless motor according to the present invention includes a step of bringing the arc surface of the magnetic pole teeth into contact with a cylindrical assembly jig to align the magnetic pole teeth.
It is possible to provide a method for manufacturing a single-phase brushless motor which can reduce cogging torque, obtain sufficient starting torque, and easily secure assembly accuracy.

The method for manufacturing a single-phase brushless motor according to the present invention includes a step of manufacturing an insulating member assembly having a plurality of insulating members, a step of causing the insulating member to hold the magnetic pole teeth, and a cylindrical assembly jig. since a step which is brought into contact with the arcuate face of the pole teeth to align the magnetic pole teeth, it is possible to obtain a sufficient starting torque can be reduced cogging torque, and can be easily secured assembling accuracy single A method for manufacturing a phase brushless motor can be provided.

It is sectional drawing which shows the structure of the single-phase brushless motor which is Embodiment 1 of this invention. It is an enlarged view of the main part which shows the main part of the single-phase brushless motor of FIG. It is explanatory drawing which shows the relationship between the angle θα and torque. It is sectional drawing which shows the structure of the conventional single-phase brushless motor for comparison with the single-phase brushless motor of FIG. It is explanatory drawing for demonstrating the characteristic of the single-phase brushless motor of FIG. It is a partially enlarged view of FIG. It is explanatory drawing for demonstrating the assembly procedure of a single-phase brushless motor. It is sectional drawing which shows the structure of the stator of the single-phase brushless motor which is Embodiment 2. FIG. It is sectional drawing which shows the structure of the stator of the single-phase brushless motor which is 3rd Embodiment.

Embodiment 1.
1 to 6 show a first embodiment for carrying out the present invention, FIG. 1 is a cross-sectional view showing a configuration of a single-phase brushless motor, and FIG. 2 shows a main part of the single-phase brushless motor. The enlarged view of the main part and FIG. 3 are explanatory views showing the relationship between the angle θα and the torque. FIG. 4 is a cross-sectional view showing the configuration of a conventional single-phase brushless motor for comparison with the single-phase brushless motor of FIG. 1, FIG. 5 is an explanatory view for explaining the characteristics of the single-phase brushless motor, and FIG. 6 is FIG. A partially enlarged view of the above, FIG. 7 is an explanatory view for explaining an assembly procedure of a single-phase brushless motor. FIG. 1 shows a cross section of the single-phase brushless motor 100 in the radial direction of the rotor 10. The single-phase brushless motor 100 has a rotor 10, a shaft 18, and a stator 20. Although not shown, a frame for holding the stator 20 and a bracket for rotatably supporting the rotor 10 are provided around the stator 20.

The rotor 10 has a cylindrical permanent magnet 11 in which a plurality of magnetic poles 12 are formed. The rotor 10 is fitted to the shaft 18, is arranged to face the inner peripheral side of the stator 20 via a gap, and is rotatably supported by a bracket via a bearing (not shown). The rotor 10 has a magnetic pole 12 having a total of four poles, N pole and S pole, and has a hollow cylindrical shape in which each is integrally connected. The permanent magnet 11 uses a neodymium sintered magnet (residual magnetic flux density (Br) 0.9 to 1.4 T), which is a hard magnetic material having a higher coercive force than the soft magnetic material. The magnetization direction of the permanent magnet 11 may be any of a parallel direction facing the same direction, a radial direction extending radially from the center of rotation, and a direction connecting in a bicurve shape, and at any timing of magnet manufacturing or magnetizing. The magnetizing direction is determined and the north and south poles are formed. The shaft 18 may be either a soft magnetic material or a non-magnetic material, but in this embodiment, a soft magnetic material, for example, carbon steel S10C for machine structure specified in Japanese Industrial Standards is tempered and used. Further, although not shown, a cylindrical member for preventing scattering is provided on the outer peripheral portion of the rotor 10. As an example of a cylindrical member, a fiber reinforced plastic (FRP) in which a thin plate made of SUS (stainless steel) having a thickness of about 0.2 mm is formed into a cylindrical shape and its peripheral end is fixed by welding or the like to cover the outer circumference of the rotor 10. Is wound around the outer circumference of the rotor 10 to form a cylindrical member, and the like. Cylindrical members are not essential. The rotor 10 rotates in the direction of the arrow R, which is the clockwise direction.

Next, the configuration of the stator 20 will be described. The stator 20 has a plurality of stator pieces 21 and a yoke coupling piece 28 that magnetically connects them. The stator piece 21 has a core piece 22, an insulator 26, and a coil 27. The core piece 22 has a yoke piece 23 and a magnetic pole tooth 24 projecting from the central portion of the yoke piece 23 toward one side. The core piece 22 is formed by laminating a predetermined number of magnetic steel sheets having a thickness of about 0.2 to 1.2 mm punched into a T shape, and the yoke piece 23 and the magnetic pole tooth 24 are integrally formed. ing. The magnetic pole tooth 24 has one end 241 and the other end 248 (indicated by a virtual line) on the opposite side. One end 241 has shoes 242 and 243 on both sides in the circumferential direction. Although details will be described later, an arc surface 244 and a plane 245 as an adjacent surface are formed on one end 241. The virtual arc plane VC shown in FIG. 2 is a virtual arc plane. The core piece 22 having the yoke piece 23 and the magnetic pole teeth 24 and the yoke coupling piece 28 are the stator cores in this embodiment.

Here, the arc surface 244, the plane 245, and the virtual arc surface VC will be described in detail with reference to FIG. In FIG. 2, the arc surface 244 is an arc surface having a radius r1 centered on the shaft center line E of the rotor 10. The plane 245 is a plane adjacent to the arc surface 244 at the connecting portion L. The virtual arc plane VC is an arc plane having a radius r1 centered on the shaft center line E of the rotor 10 extending in the counterclockwise direction in FIG. 2 from the connecting portion L between the arc plane 244 and the plane 245. Here, the connecting portion L is on a plane Fb rotated by a constant angle θA (counterclockwise is positive (plus)) with respect to the central surface Fa in the length direction of the magnetic pole tooth 24. The plane 245 is located between the orthogonal plane Fc and the tangent plane Fd, and the angle formed with the orthogonal plane Fc is set to θα (described later). The orthogonal plane Fc is a plane that passes through the connecting portion L and is orthogonal to the central surface Fa of the magnetic pole teeth 24. The tangent plane Fd is a tangent plane of the arc plane 244 at the connecting portion L between the arc plane 244 and the plane 245. Assuming that the angle formed by the tangent plane Fd and the orthogonal plane Fc is the angle θB, there is a relationship of angle θα <angle θB, angle θB = angle θA. One end portion 241 has a shape in which the virtual arc surface VC is linearly cut out by the plane 245. The plane 245 is located closer to the other end 248 than the virtual arc plane VC. Moreover, the plane 245 is located at a position farther from the virtual arc plane VC than the tangent plane Fd. Further, the plane 245 is located closer to the virtual arc plane VC than the orthogonal plane Fc.

To fix the laminated electromagnetic steel sheets, for example, each electromagnetic steel sheet is provided with a crimping portion (not shown) and crimped to each other to be fixed, or after laminating, it is welded in the laminating direction at any position in the circumferential direction. Alternatively, it can be carried out by a method such as interposing an adhesive between the electrical steel sheets and fixing them by heating. An insulator 26 is provided around the magnetic pole tooth 24, and a coil 27 is wound around the insulator 26. The four stator pieces 21 are arranged on the four sides of the square, and the yoke pieces 23 are magnetically connected by a total of four yoke coupling pieces 28 to form a four-pole stator 20 having an annular yoke. There is. A slot 29 is formed between the magnetic pole teeth 24, and the coil 27 is housed in the slot 29.

The insulator 26 is a member that electrically insulates the core piece 22 and the coil 27, and an insulating material such as resin is used. In the case of a thin film, the space for arranging the coil 27 can be widened, so that the cross-sectional area of the coil 27 can be increased to reduce the electrical resistance, and the efficiency of the motor can be improved. Further, if the insulator 26 is formed by injection molding or compression molding, the insulator 26 can also play a role of fixing and supporting the winding frame when the coil 27 is wound around the magnetic pole teeth 24 via the insulator 26 and the terminal of the coil 27. it can. The coil 27 has an insulating coating of several to several tens of μm on the surface, and a copper wire or an aluminum wire having a round or square cross section is used. An armature magnetic flux is generated from the stator 20 by supplying a current to the coil 27. The larger the number of turns and the larger the current flowing through the coil 27, the larger the magnetic flux generated from the stator 20. Therefore, it is preferable to reduce the resistance or increase the number of turns as much as possible, and the larger the cross-sectional area of the coil 27 arranged in the slot 29, the better the performance of the motor.

A rotor 10 fitted to the shaft 18 is arranged on the inner peripheral portion (inside) of the stator 20 as described above with a gap between the rotor 10 and the magnetic pole teeth 24. The radial gap G between the arcuate surface 244 and the rotor 10 in the rotor 10 (hereinafter, simply referred to as the radial direction) is a predetermined value, and the radial gap between the plane 245 and the rotor 10 is counterclockwise from the connecting portion L. It becomes larger as it goes away in the clockwise direction.

Next, the angle θA, the angle θB, and the angle θα will be described. The angle θA is defined as the angle formed by the plane Fb connecting the connecting portion L and the shaft center line E and the center surface Fa of the magnetic pole tooth 24. The center surface Fa of the magnetic pole tooth 24 is the shaft center line E. It is assumed that you will pass through. Therefore, as described above, the angle θA and the angle θB are equal. Therefore, the angle θB is uniquely determined by how the angle θA is selected. Since the angle θA determines the width of the arcuate surface 244 concentric with the shaft center line E, if it is desired to minimize the axial tilt of the magnetic pole teeth 24 during assembly, the angle θA should be as large as possible. On the contrary, if the tilt is allowed to some extent, it is reduced, but from a practical point of view, the angle θA> = 0, that is, the connecting portion L, which is the end line in the counterclockwise direction of the arc surface 244, is at least opposite to the central surface Fa. Set it to be on the clock side.

Next, a method of determining the angle θα formed by the plane 245 and the orthogonal plane Fc will be described. FIG. 3 is a diagram showing the relationship between the magnitude of the angle θα and the three types of torque required as the characteristics of the single-phase brushless motor when the angle θA is set to a predetermined value. FIG. 3 shows the steady torque τn, the torque ripple τr of the steady torque τn, and the starting torque τs. The steady torque τn and the torque ripple τr increase as the angle θα increases, and the starting torque τs increases as the angle θα increases. Decrease. The torque ripple τr is defined as torque ripple τr = (maximum value of steady-state torque τn-minimum value of steady-state torque τn) / 2. Since the steady torque τn, torque ripple τr, and starting torque τs differ depending on the required specifications of the product equipped with the single-phase brushless motor, the value of the angle θα is selected according to the required specifications. For example, when the moment of inertia of a load attached to a single-phase brushless motor (for example, a fan blade) is large, the value of the angle θα is reduced so that the starting torque τs becomes large. On the contrary, when the moment of inertia of the attached load is small but the load torque during operation is large, the value of the angle θα is increased so that the steady torque τn becomes large. Further, since the torque ripple τr leads to vibration and noise, when low vibration and low noise are required, the angle θα is selected to a small value so that the torque ripple τr becomes small. In either case, the angle θA and the angle θα may be appropriately selected according to the required specifications.

However, when the angle θα is larger than the angle θB and the plane 245 does not fall within the range of the angle θB, that is, when the plane 245 comes out to the inner peripheral side of the tangent plane Fd of the arc surface 244 drawn from the connecting portion L, the plane The arc surface 244 interferes with the core mold (see the core mold CC in FIG. 7), and the arc surface 244 cannot be brought into contact with the core mold CC for centering. Therefore, when assembling the divided stator piece 21, the arc surface It becomes difficult to secure the accuracy such as the roundness and the coaxiality of the inner circle formed by 244. Further, when the plane 245 comes out on the other end 248 side of the orthogonal plane Fc, the thickness of the shoe 243 in the radial direction becomes thin, which causes a decrease in torque. If the plane 245 falls within the range of the angle θB (0 = <θα <= θB), the assembly accuracy can be easily obtained and the torque does not decrease. The arcuate surface 244 may be chamfered or rounded at the clockwise end of FIG. 2 or the counterclockwise end of the plane 245.

Next, the characteristics of the single-phase brushless motor having such a configuration will be described in comparison with the conventional ones. First, the single-phase brushless motor according to the first embodiment is characterized in that the starting torque τs is larger than that of the conventional motor. FIG. 4 shows a case where the invention described in Japanese Patent Application Laid-Open No. 2012-029515 (hereinafter, simply referred to as prior art) is applied to a single-phase brushless motor having the same size and configuration as the first embodiment of the present invention. It is sectional drawing which shows the structure of the single-phase brushless motor of. However, the prior art is an outer rotor type single-phase brushless motor. As shown in FIG. 4, the single-phase brushless motor 900 has a stator 90. The stator 90 has an insulator 26, a coil 27, a magnetic pole tooth 94, an annular yoke 98, and a slot 99. The magnetic pole teeth 94 are projected at four locations from the inner peripheral side of the annular yoke 98. The magnetic pole teeth 94 has one end 941 and the other end 948 (indicated by a virtual line) on the opposite side. One end 941 has shoes 942 on both sides in the circumferential direction, and an arc surface 944 is formed. The arc surface 944 is an arc surface having a radius r1 centered on the shaft center line E of the rotor 10.

Further, at one end 941, a groove 945 having a rectangular cross section is formed at a position rotated by a predetermined angle counterclockwise from the center of the arc surface 944 (the shoe 942 on the counterclockwise side of the shoes on both sides). Is provided. The yoke 98 and the magnetic pole tooth 94 are formed by laminating a predetermined number of electrical steel sheets having a thickness of about 0.2 to 1.2 mm punched into a shape having an annular portion and protrusions protruding inward from four points of the annular portion. It is formed, and the yoke 98 and the magnetic pole tooth 94 are integrally formed. The WJ is a nozzle for winding the coil 27 around the magnetic pole tooth 94, and illustrates a state when the coil 27 is wound around the magnetic pole tooth 94. Since the other configurations are the same as those of the first embodiment shown in FIG. 1, the corresponding ones are designated by the same reference numerals and the description thereof will be omitted.

In the single-phase brushless motor configured as described above, the peak of the cogging torque can be lowered by providing the groove portion 945 at one end of the magnetic pole teeth 94. By the way, in a single-phase brushless motor, unlike a case where alternating currents having different phases are passed through a plurality of magnetic pole teeth as in a three-phase motor, alternating currents having the same phase are passed through the magnetic pole teeth. Further, the number of magnetic pole teeth and the number of magnetic poles of the rotor are generally the same. In a single-phase brushless motor having such a configuration, there is a point where the torque becomes zero. Further, when the number of poles is small (for example, when there are four poles as in the present embodiment), in general, the shoe spacing of each magnetic pole tooth is often wide and the cogging torque is relatively large. At the point where the cogging torque becomes 0, that is, the magnetic pole teeth and the magnetic pole centers of the rotor coincide with each other, the magnetic pole teeth and the magnetic poles of the rotor by the permanent magnets are strongly attracted in the radial direction. At this point, when the rotor is stationary, there is a problem that the DC current applied at the time of starting must be controlled in a complicated manner in order to obtain the starting torque, which is difficult.

In the single-phase brushless motor having such characteristics, the torque characteristics of the single-phase brushless motor 100 of the first embodiment of the present invention and the conventional single-phase brushless motor 900 are compared. FIG. 5 is a graph in which the horizontal axis is the rotation angle deg of the rotor 10 and the vertical axis is the torque. FIG. 6 is a partially enlarged view of FIG. In these figures, the position where the rotation angle deg of the horizontal axis is 0 is the position where the magnetic pole center of the rotor 10 overlaps the center of the magnetic pole teeth 24 (94) of the stator 20 (90). 5 (a) and 6 (a) show the characteristics of the conventional single-phase brushless motor 900. The curve a1 in the graph is the steady torque when an alternating current is applied, and the curve b1 is the cogging torque and the curve. c1 indicates the starting torque when a direct current is applied (DC is applied at the time of starting). The point representing the starting torque, which is the torque at the position where the cogging torque on the curve c1 becomes 0, is designated as p1, and is indicated by the ◇ type mark in the figure. 5 (b) and 6 (b) show the characteristics of the single-phase brushless motor 100 according to the present embodiment. The curve a2 in the graph is the steady torque when an alternating current is applied, and the curve b2 is the cogging. The torque and the curve c2 show the starting torque which is the torque when a direct current is applied. The point representing the starting torque, which is the torque at the position where the cogging torque on the curve c2 becomes 0, is designated as p2, and is indicated by the ◇ type mark in the figure.

Looking at how much starting torque can be obtained at the position where the cogging torque is 0 in both cases, the conventional single-phase brushless motor 900 has a deviation between the position where the cogging torque is 0 and the center of the magnetic pole teeth 94. Since it is small, the starting torque, which is the torque when a direct current is applied at that time, is as small as p1. On the other hand, in the single-phase brushless motor 100 of the present embodiment, since the position where the cogging torque becomes 0 and the center of the magnetic pole teeth 24 have a large deviation, the starting torque, which is the torque when a direct current is applied, is as large as p2. Is obtained. The reason for this is briefly described below. The position where the cogging torque becomes 0 is the position where the magnetic pole tooth 24 (94) and the magnetic pole 12 of the rotor 10 are most attracted to each other. In other words, the cogging torque becomes 0 at the position where the distance between the magnetic pole tooth 24 and the magnetic pole 12 which are magnetic materials is the shortest.

In the conventional single-phase brushless motor, the pulling force is weakened at the position of the groove 945, but in the shoe 942 provided with the groove 945, the gap between the shoe 942 and the rotor 10 on both sides of the groove 945 in the circumferential direction is the same size. Since the shoe 942 and the magnetic poles 12 of the rotor 10 are attracted to each other on both the clockwise side and the counterclockwise side with the groove portion 945 in between, the position where the cogging torque becomes 0 as a result may be greatly deviated from the center of the magnetic pole teeth 94. Absent. On the other hand, in the single-phase brushless motor 100 of the present embodiment, the arc surface 244 and the flat surface 245, which are the surfaces of the magnetic pole teeth 24 facing the rotor 10, gradually widen in the counterclockwise direction with the connecting portion L as a boundary. The gap becomes the largest at the end of the shoe 243 on the counterclockwise side. Therefore, the force attracting the magnetic pole teeth 24 and the magnetic poles 12 of the rotor 10 gradually increases from the counterclockwise direction in FIG. 2 of the shoe 243 toward the clockwise direction, and the position (that is, the position where the cogging torque becomes 0). ) Is largely deviated in the clockwise direction from the central surface Fa of the magnetic pole tooth 24. The more the position where the cogging torque becomes 0 deviates from the central surface Fa of the magnetic pole tooth 24, the easier it is to obtain the starting torque.

Another action and effect according to this embodiment will be described. FIG. 7 shows the process of assembling the single-phase brushless motor 100. As described above, since the core piece 22 and the yoke coupling piece 28 can be separated, the coil 27 is first wound around the magnetic pole tooth 24 to manufacture the stator piece 21, and then the stator piece 21 and the yoke coupling piece 28 are manufactured. By assembling and, when winding the coil 27 around the magnetic pole tooth 24, the circumference of the magnetic pole tooth 24 can be widened, and the coil 27 can be easily wound at high speed with a flyer or the like. Since the winding nozzle (see the winding nozzle WJ in FIG. 4) can be easily brought close to the magnetic pole tooth 24, it is not necessary to leave a space for inserting the winding nozzle WJ, and the cross-sectional area of the coil 27 is (Number of turns) can be increased.

On the other hand, in the conventional single-phase brushless motor 900 of FIG. 4, since the magnetic pole tooth 94 and the annular yoke 98 are integrated as shown in FIG. 4, the winding nozzle WJ is inserted from the inner peripheral side to insert the coil 27. Need to be wound around. Then, it is necessary to secure a space for the winding nozzle WJ to enter the depth of the slot 99, and as a result, the cross-sectional area (number of turns) of the coil has to be smaller than that of the single-phase brushless motor 100 of FIG. .. That is, in the single-phase brushless motor 100 of the present embodiment, the cross-sectional area of the coil 27 is large, and copper loss can be reduced as compared with the conventional case. Further, since the conventional one has a groove portion 945, the thickness of the shoe 943 (diametrical dimension of the stator 90) in the vicinity of the groove portion 945 is small, the magnetic flux density is locally increased in the groove portion, and the iron loss is increased. .. On the other hand, in the single-phase brushless motor 100 of the present embodiment, since the thickness of the shoe 243 on the flat surface 245 side is gradually reduced, the magnetic flux density does not increase locally, and compared with the conventional single-phase brushless motor. The iron loss can be kept low. From the above, the single-phase brushless motor 100 of the present embodiment can obtain a good starting torque, low copper loss, low iron loss, and can be made highly efficient.

Such a single-phase brushless motor 100 can be used for all purposes. For example, it is suitable as a drive source for small household electric appliances such as vacuum cleaners in which a motor or a drive circuit needs to be arranged in a limited space. Since the single-phase drive type motor has a small number of phases, the drive circuit configuration can be made simple and compact, and space can be saved.

The single-phase brushless motor of the present embodiment manufactures the stator 20 by combining the stator piece 21 having the core piece 22 and the yoke coupling piece 28. In the divided stator piece 21, after the coil 27 is wound around the magnetic pole teeth 24, the yoke piece 23 is magnetically connected by the yoke coupling piece 28, and the rotor 10 is accommodated on the arcuate surface 244 of the plurality of stator pieces 21. It must be assembled so that the cylindrical portion to be formed is formed. Hereinafter, an accurate assembly method will be described. First, the coil 27 is wound around the magnetic pole tooth 24 to prepare four stator pieces 21. Next, as shown in FIG. 7, the core type CC as an assembly jig is arranged in the center. The core type CC is a columnar one made by adding a gap to the diameter of the rotor 10. Next, each stator piece 21 uses the arc surface 244 of the magnetic pole tooth 24 to bring the arc surface 244 into contact with the core type CC, and in this state, the yoke coupling piece 28 is brought into contact with each yoke piece 23. The arc surface 244 is aligned and the stator piece 21 is aligned in the circumferential direction. By doing so, the center line of the arc surface 244 of the plurality of magnetic pole teeth 24 and the shaft center line E (see FIG. 2) can be accurately aligned, and the arc surface 244 of the magnetic pole teeth 24 is formed. It is possible to secure the roundness of the cylindrical surface to be formed. As a result, a stable starting torque can be obtained, and vibration and noise when the single-phase brushless motor rotates can be suppressed.

Further, as a better example, since the angle θA formed by the plane Fb shown in FIG. 2 and the central surface Fa of the magnetic pole teeth 24 is set to plus (counterclockwise direction is plus), the arc surface 244 is used as a reference. When assembling each stator piece 21, the length of the arc of the arc surface 244 that comes into contact with the core type CC can be increased, the stator piece 21 does not easily fall down, and the stator piece 21 can be assembled with high accuracy.

Embodiment 2.
FIG. 8 is a cross-sectional view showing the configuration of the stator of the single-phase brushless motor according to the second embodiment. In this embodiment, the stator 50 has a connecting portion 55. The connecting portion 55 foldably connects the yoke piece 23 of the stator piece 21 and the yoke coupling piece 28 by plastically deforming them. That is, the outer peripheral portion of the yoke piece 23 and the yoke coupling piece 28 are connected by the connecting portion 55, and the connecting portion 55 is plastically deformed to be bendable. The core piece 22 and the yoke coupling piece 28 can be closed and opened around the connecting portion 55. The core piece 22 having the yoke piece 23 and the magnetic pole teeth 24 and the yoke coupling piece 28 are the stator cores in this embodiment. Since the other configurations are the same as those of the first embodiment shown in FIG. 1, the corresponding ones are designated by the same reference numerals and the description thereof will be omitted.

When winding the coil 27 around the magnetic pole teeth 24, the core piece 22 is opened and wound. Therefore, as in the first embodiment, the coil 27 can be easily wound and the coil area can be increased. When assembling, as in the first embodiment, the arc surface 244 of the stator piece 21 is sequentially brought into contact with the core type CC, bent in the direction of the arrow Z, and the stator piece 21 is arranged so as to go around the core type CC. To do.

As a result, the center line of the arcuate surface 244 of the plurality of magnetic pole teeth 24 and the shaft center line E (see FIG. 2) can be accurately aligned as in the first embodiment, and the magnetic pole teeth 24 can be aligned. The roundness of the cylindrical surface formed by the arc surface 244 can be ensured. Therefore, a stable starting torque can be obtained, and vibration and noise when the single-phase brushless motor rotates can be suppressed. Further, the core pieces 22 can be integrally handled in a state of being connected by the connecting portion 55, which facilitates transportation and handling on the production line.

Embodiment 3.
9A and 9B show the configuration of the stator of the single-phase brushless motor according to the third embodiment, FIG. 9A is a cross-sectional view of the vicinity of the magnetic pole teeth 64, and FIG. 9B is a plan view of the yoke. In this embodiment, the magnetic pole teeth 64 and the yoke 68 of the stator piece 61 are separately manufactured. The magnetic pole tooth 64 has an exposed other end 648 as shown in FIG. 9 (a). Further, the insulator assembly 67 as an assembly of insulating members is provided, and the insulator assembly 67 accommodates and holds four magnetic pole teeth 64, which are equivalent to one single-phase brushless motor, and is an insulator as four insulating members. 66 is integrally formed of, for example, an insulating resin. Further, the insulator 66 has a tubular portion 66a having a rectangular cross section, and magnetic pole teeth 64 are housed in the tubular portion 66a as shown in FIG. 9A, and a coil 27 is provided on the outer peripheral portion of the tubular portion 66a. Is wound around. Therefore, in the state where the magnetic pole teeth 64 and the insulator 66 are combined, the four magnetic pole teeth 64 are supported by the four insulators 66 integrally formed. The magnetic pole teeth 64 and the yoke 68 are the stator cores in this embodiment. Since the other configurations are the same as those of the first embodiment shown in FIG. 1, the corresponding ones are designated by the same reference numerals and the description thereof will be omitted.

Prior to winding the coil 27 around the magnetic pole teeth 64, first, the magnetic pole teeth 64 are sequentially inserted into the four insulators 66 from the inner peripheral side of the insulator assembly 67. At this time, the inner diameter of the cylindrical surface formed on the arc surface 244 of the magnetic pole teeth 64 with all the magnetic pole teeth 64 inserted is set to be slightly larger than the diameter of the core type CC. Then, the core type CC is inserted with all the magnetic pole teeth 64 inserted, and the arc surface 244 of the magnetic pole teeth 64 is brought into contact with the core type CC to position the four magnetic pole teeth 64. Next, a winding machine is placed on the side of the magnetic pole teeth 64, and the coil 27 is wound around the insulator 66. After that, the yoke 68 is inserted from the direction perpendicular to the paper surface of FIG. 9A and fixed integrally with the magnetic pole tooth 24. The fixing method may be any joining method such as press-fitting, shrink-fitting, bonding, and welding. Further, the coil 27 may be wound around the insulator 66, and then the magnetic pole teeth 64 may be sequentially inserted and held in the insulator 66.

Since the magnetic pole teeth 64 divided in this way can be integrally held by the insulator assembly 67, the magnetic pole teeth 64 can be easily handled until they are fixed to the yoke 68. Further, the work of winding the coil 27 by four poles and the work of connecting the coils 27 to each other become easy. It should be noted that two insulator aggregates having two integrated insulators can be used, and the same effect can be obtained.

The single-phase brushless motor as described above can accurately align the center line of the arcuate surface 244 of the plurality of magnetic pole teeth 64 with the shaft center line E, as in the first embodiment, and can accurately align the magnetic pole teeth 64. The roundness of the cylindrical surface formed by the arc surface 244 can be ensured. Therefore, a stable starting torque can be obtained, and vibration and noise when the single-phase brushless motor rotates can be suppressed.

In each of the above embodiments, the rotor 10 having a cylindrical permanent magnet 11 in which each magnetic pole is integrally formed is shown, but the rotor 10 is composed of a plurality of permanent magnets divided for each magnetic pole. May be good. Further, when a plurality of permanent magnets divided for each magnetic pole are used, a yoke body may be provided to connect the magnetic poles formed by the permanent magnets.

The permanent magnet 11 forming the rotor 10 is a hard magnetic material having a higher coercive force than the soft magnetic material. The material of the permanent magnet 11 may be any kind, for example, a ferrite bond magnet (residual magnetic flux density (Br) 0.2 to 0.3T) composed of ferrite magnet powder and resin, and a ferrite sintered magnet (Br 0.35 to 0. 45T), neodymium bond magnets (Br0.5 to 0.8T), sama iron nitrogen bond magnets (Br0.5 to 0.8T), neodymium sintered magnets (Br0.9 to 1.4T) and the like. The materials listed above differ in magnetic flux, density, strength, etc., but may be appropriately selected according to the torque, output, and usage environment required for the single-phase brushless motor. Normally, a material having a higher residual magnetic flux density Br is selected as the torque or output is larger. When used at high temperatures, ferrite magnets that do not demagnetize at high temperatures and neodymium sintered magnets with high coercive force are desirable.

The shaft 18 may be either a soft magnetic material or a non-magnetic material. Examples of the soft magnetic material include steel materials such as carbon steels S10C and SS400 for machine structure specified in Japanese Industrial Standards, and examples of non-magnetic materials include stainless steel (SUS). In addition, these materials may be hardened in order to increase the strength.

For the magnetic pole teeth and yoke, a thin magnetic material such as an electromagnetic steel plate or SPCC having a thickness of about 0.2 to 1.2 mm can be used. The magnetic material is appropriately selected according to the torque, rotation speed, and output required for the single-phase brushless motor. For example, in a motor having a high rotation speed, the smaller the holding force and the thinner the motor, the lower the iron loss and the better the efficiency.

Further, as described above, when manufacturing a single-phase brushless motor, by positioning the arc surface of the magnetic pole teeth in contact with the core mold, the magnetic pole teeth can be positioned quickly and accurately, and is stable. It is possible to provide a method for manufacturing a single-phase brushless motor, which can obtain a starting torque, suppress vibration and noise when rotating, and easily secure assembly accuracy.

In the above embodiment, the adjacent surface is a plane (plane 245), but the surface is not limited to the plane, and the radial cross section of the stator connected by the connecting portion L is a clothoid curve. It may be a clothoid curved surface, an involute curved surface which is an involute curve, or the like.

In the above embodiment, the inner rotor type in which the rotor provided inside the stator rotates is shown, but the outer rotor type in which the inner stator is fixed and the rotor arranged on the outside rotates. Even if it is, it has the same effect.
Further, in the present invention, it is possible to freely combine the above-described embodiments, or to modify or omit the embodiments as appropriate, within the scope of the invention.

10 rotors, 11 permanent magnets, 12 magnetic poles, 20 stators, 21 stator pieces,
22 core pieces, 23 yoke pieces, 24 magnetic pole teeth, 27 coils,
28 yoke coupling piece, 50 stator, 55 connecting part, 61 stator piece,
64 magnetic pole teeth, 66 insulators, 67 insulator aggregates,
68 yoke, 94 magnetic pole teeth, 100 single-phase brushless motor,
200 single-phase brushless motor, 241 ends, 244 arc surfaces, 245 planes,
248,648 ends.

Claims (16)

A single-phase brushless motor having a rotor and a stator,
The rotor has a cylindrical shape and has a plurality of magnetic poles formed by permanent magnets.
The stator has a stator core and a coil.
The stator core has a yoke and a plurality of magnetic pole teeth.
The magnetic pole tooth has one end and the other end, and is formed at the one end by connecting an arc plane centered on the center line of the rotor and connecting the arc plane to the connecting portion. It has a surface, and the adjacent surface is extended at the same position as the tangent plane of the arc surface at the connection portion between the arc surface and the adjacent surface or with the same curvature as the arc surface from the tangent plane. It is a plane formed so as to be located far from the virtual arc plane.
The coil is wound around the magnetic pole teeth,
The arc surface and the adjacent surface are arranged to face the rotor with a gap in the radial direction of the rotor.
The other end is magnetically coupled to the yoke.
Single-phase brushless motor. The single-phase brushless motor according to claim 1, wherein the adjacent surface is arranged to face the rotor so that the radial gap between the adjacent surface and the rotor increases as the distance from the arc surface increases. The single-phase brushless motor according to claim 2, wherein the arc surface is arranged to face the rotor with a constant radial gap between the arc surface and the rotor. The one end has a first shoe and a second shoe, the arc surface is formed on the first shoe, and the radial thickness of the second shoe is from the arc surface. The single-phase brushless motor according to any one of claims 1 to 3, wherein the adjacent surfaces are formed so as to become smaller as the distance increases. The single-phase brushless motor according to claim 4, wherein the connecting portion is located on the central surface of the magnetic pole teeth or on the second shoe side of the central surface. The connection portion is located on the central surface of the magnetic pole teeth and
The single-phase brushless motor according to any one of claims 1 to 5, wherein the adjacent surface is located at the same position as the tangent plane of the arc surface at the connection portion. The adjacent surface is formed so as to be located on the same orthogonal plane as the orthogonal plane passing through the connecting portion and orthogonal to the central surface of the magnetic pole teeth or at a position closer to the virtual arc plane than the orthogonal plane. The single-phase brushless motor according to any one of claims 1 to 5. The single-phase brushless according to any one of claims 1 to 7, wherein the stator core is formed by combining the magnetic pole tooth and a plurality of core pieces having a yoke piece corresponding to the magnetic pole tooth. motor. The single-phase brushless motor according to claim 8, wherein the core piece is formed by integrally forming the magnetic pole tooth and the yoke piece. The single-phase brushless motor according to claim 8 or 9, wherein the stator core has a yoke coupling piece that magnetically couples the yoke pieces. The single-phase brushless motor according to any one of claims 8 to 10, wherein the stator core is configured by connecting the plurality of core pieces so as to be bendable to each other. The single-phase brushless according to any one of claims 1 to 7, wherein the stator core is formed by combining a plurality of magnetic pole teeth formed separately from the yoke and the yoke. motor. The vacuum cleaner provided with the single-phase brushless motor according to any one of claims 1 to 12 . The method for manufacturing a single-phase brushless motor according to any one of claims 8 to 12, wherein the arc surface of the magnetic pole tooth is brought into contact with a cylindrical assembly jig to position the magnetic pole tooth. It has a process of matching
Manufacturing method of single-phase brushless motor. The method for manufacturing a single-phase brushless motor according to claim 12, wherein a step of manufacturing an insulating member assembly having a plurality of insulating members, and a step of causing the insulating member to hold the magnetic pole teeth.
It has a step of bringing the arc surface of the magnetic pole teeth into contact with a cylindrical assembly jig to align the magnetic pole teeth.
Manufacturing method of single-phase brushless motor. A method for manufacturing an electric vacuum cleaner, wherein the single-phase brushless motor in the electric vacuum cleaner is manufactured by using the method for manufacturing a single-phase brushless motor according to claim 14 or 15. Method.

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