JP2017135766A - Single-phase brushless motor and manufacturing method of single-phase brushless motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a single-phase brushless motor capable of reducing a cogging torque and obtaining a sufficient start torque.SOLUTION: A stator piece 21 comprises a core piece 22 including a yoke piece 23 and magnetic pole teeth 24 and a coil 27 which is wound around the magnetic pole teeth 24, and a stator 20 is formed by connecting the stator piece 21 via four yoke coupling pieces 28. In an end portion 241 of the magnetic pole teeth 24, an arcuate surface 244 and a plane 245 adjacent to the arcuate surface 244 in a connection part L are provided. The plane 245 is positioned between an orthogonal plane Fc which passes the connection part L and is orthogonal with a central face Fa of the magnetic pole teeth 24, and a contact plane Fd in the connection part L of the arcuate surface 244, and configured in such a manner that a clearance between the plane 245 and a rotor 10 in a radial direction of the rotor 10 becomes larger in a counter-clockwise direction from the connection part L.SELECTED DRAWING: Figure 2

Description

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

  As a conventional single-phase brushless motor, a rotor having a plurality of magnetic poles and a stator having a number of salient poles arranged with a gap from the rotor and having the same number of salient poles as the plurality of magnetic poles of the rotor, An outer rotor type single-phase brushless motor has been proposed which has a groove provided on a salient pole surface opposite to a circumferential direction from the center to the end.

JP2012-029515A

The conventional single-phase brushless motor is configured as described above, and causes a starting instability by providing a groove on the salient pole surface facing the rotor at a position near the circumferential center of the salient pole toward the end. The peak value of the cogging torque can be lowered without any problem, but there is almost no effect of shifting the point where the cogging torque becomes zero from the center of the salient pole, and it is difficult to obtain a sufficient starting torque. there were. Also, if a groove is provided at a position near the end of the salient pole surface in the circumferential direction, the magnetic flux in the peripheral portion where the groove is provided is disturbed, and the magnetic flux density is locally increased, resulting in iron loss. Increase.
The present invention provides a single-phase brushless motor capable of reducing the cogging torque and obtaining a sufficient starting torque, and a method for manufacturing the single-phase brushless motor. Objective.

In the single-phase brushless motor according to the present invention,
A single-phase brushless motor having a rotor and a stator,
The rotor is cylindrical 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 teeth have one end and the other end, and the one end has an arcuate surface and an adjacent surface formed by connecting the arcuate surface and the connecting portion, and the adjacent surface is A plane or curved surface formed so as to be positioned closer to the other end than a virtual arc surface extended with the same curvature as the arc surface from the connecting portion between the arc surface and the adjacent surface. ,
The coil is wound around the magnetic pole teeth,
The magnetic pole teeth are arranged so that the arc surface is opposed to the rotor with a certain gap in the radial direction of the rotor, and the radial gap between the adjacent surface and the rotor increases as the distance from the arc surface increases. In this way, the adjacent surface is arranged to face the rotor, and the other end is magnetically coupled to the yoke.

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

  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 holding the magnetic pole teeth on the insulating members, and a cylindrical assembly jig The method includes a step of aligning the magnetic pole teeth by contacting the arc surface of the magnetic pole teeth.

The single-phase brushless motor according to the present invention is
The magnetic pole teeth have one end and the other end, and the one end has an arc surface and an adjacent surface connected to the arc surface, and the adjacent surface is the arc. Since it is a plane or curved surface formed so as to be located at a position that is the same as or far from the virtual arc surface extended from the connection portion between the surface and the adjacent surface with the same curvature as the arc surface,
A single-phase brushless motor capable of reducing cogging torque and obtaining sufficient starting torque can be obtained.

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

  The method of 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 holding the magnetic pole teeth on the insulating members, and a cylindrical assembly jig with the step And the step of aligning the magnetic pole teeth with the arcuate surface of the magnetic pole teeth, so that the cogging torque can be reduced, sufficient starting torque can be obtained, and the assembly accuracy can be easily secured. A method of 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 a principal part enlarged view which shows the principal part of the single phase brushless motor of FIG. It is explanatory drawing which shows the relationship between angle (theta) (alpha) and a torque. It is sectional drawing which shows the structure of the conventional single phase brushless motor for contrast 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 the elements on larger scale of FIG. It is explanatory drawing for demonstrating the assembly procedure of a single phase brushless motor. FIG. 5 is a cross-sectional view showing a configuration of a stator of a single-phase brushless motor that is a second embodiment. FIG. 6 is a cross-sectional view illustrating a configuration of a stator of a single-phase brushless motor that is a third embodiment.

Embodiment 1 FIG.
1 to 6 show a first embodiment for carrying out the present invention. FIG. 1 is a sectional view showing a configuration of a single-phase brushless motor, and FIG. 2 shows a main part of the single-phase brushless motor. FIG. 3 is an explanatory diagram showing the relationship between the angle θα and the torque. 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 diagram for explaining the characteristics of the single-phase brushless motor, and FIG. FIG. 7 is an explanatory diagram for explaining the assembly procedure of the single-phase brushless motor. FIG. 1 shows a cross section in the radial direction of the rotor 10 of the single-phase brushless motor 100. The single-phase brushless motor 100 includes the rotor 10, the shaft 18, and the stator 20. Although not shown, a frame that holds the stator 20 and a bracket that rotatably supports the rotor 10 are provided around the stator 20.

  The rotor 10 includes 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 opposed to the inner peripheral side of the stator 20 with a gap, and is rotatably supported by a bracket via a bearing (not shown). The rotor 10 has four magnetic poles 12 having N poles and S poles in total, and has a hollow cylindrical shape that is integrally connected. The permanent magnet 11 employs a neodymium sintered magnet (residual magnetic flux density (Br) 0.9 to 1.4 T) which is a hard magnetic material having a coercive force higher than that of the soft magnetic material. The magnetization direction of the permanent magnet 11 may be any one of a parallel direction facing the same direction, a radial direction extending radially from the center of rotation, and a direction connected to a hyperbola, and at any timing during magnet manufacture or magnetization. The magnetization direction is determined, and the N pole and the S pole 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 mechanical structure defined in Japanese Industrial Standards is tempered and used. Although not shown, a cylindrical member for preventing scattering is provided on the outer peripheral portion of the rotor 10. As an example of the cylindrical member, a fiber reinforced plastic (FRP) in which a SUS (stainless steel) thin plate having a thickness of about 0.2 mm is formed in a cylindrical shape and the circumferential end is fixed by welding or the like and is covered on the outer periphery of the rotor 10. There is a manufacturing method such as forming a cylindrical member around the outer periphery of the rotor 10. The cylindrical member is not essential. The rotor 10 rotates in the direction of the arrow R that is clockwise.

  Next, the configuration of the stator 20 will be described. The stator 20 includes a plurality of stator pieces 21 and a yoke coupling piece 28 that magnetically connects these pieces. The stator piece 21 includes a core piece 22, an insulator 26, and a coil 27. The core piece 22 includes a yoke piece 23 and a magnetic pole tooth 24 protruding from the central portion of the yoke piece 23 toward one side. The core piece 22 is formed by laminating a predetermined number of 0.2 to 1.2 mm thick electromagnetic steel sheets punched into a T shape, and the yoke piece 23 and the magnetic pole teeth 24 are integrally formed. ing. The magnetic teeth 24 have one end 241 and the other end 248 (shown in phantom) 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, a circular arc surface 244 and a plane 245 as an adjacent surface are formed at one end 241. Note that the virtual arc surface VC shown in FIG. 2 is a virtual arc surface. The core piece 22 having the yoke piece 23 and the magnetic pole teeth 24 and the yoke coupling piece 28 are the stator core in this embodiment.

  Here, the arc surface 244, the flat surface 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 r <b> 1 centered on the shaft center line E of the rotor 10. The plane 245 is a plane adjacent to the circular arc surface 244 in the connection portion L. The virtual arcuate surface VC is an arcuate surface having a radius r1 centered on the shaft centerline E of the rotor 10 and extending counterclockwise in FIG. 2 from the connection portion L between the arcuate surface 244 and the flat surface 245. Here, the connection portion L is on a plane Fb rotated by a constant angle θA (counterclockwise is positive (plus)) counterclockwise from the longitudinal center face Fa of the magnetic pole teeth 24. The plane 245 is located between the orthogonal plane Fc and the tangential 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 center plane Fa of the magnetic pole teeth 24. The tangent plane Fd is a tangent plane of the arc surface 244 at the connection portion L between the arc surface 244 and the plane 245. Assuming that the angle formed between the tangential plane Fd and the orthogonal plane Fc is an angle θB, the relationship of angle θα <angle θB and angle θB = angle θA is established. One end 241 has a shape in which a virtual arcuate surface VC is linearly cut out by a plane 245. The plane 245 is located at a position closer to the other end 248 than the virtual arcuate surface VC. The plane 245 is located farther from the virtual arcuate surface VC than the tangential plane Fd. Further, the plane 245 is located closer to the virtual arcuate surface VC than the orthogonal plane Fc.

  For fixing the laminated electrical steel sheets, for example, each electromagnetic steel sheet is provided with a caulking portion (not shown) to be secured by caulking each other, or after being laminated, 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 magnetic steel sheets and fixing them by heating. An insulator 26 is provided around the magnetic pole teeth 24, and a coil 27 is wound around the outer periphery thereof. Four stator pieces 21 are arranged on four sides of a square, and a total of four yoke coupling pieces 28 magnetically connect the yoke pieces 23 to form a four-pole stator 20 having an annular yoke. Yes. Note that a slot 29 is formed between the magnetic pole teeth 24, and the coil 27 is accommodated 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. If the film is a thin film, the space in which the coil 27 is disposed can be widened, so that the cross-sectional area of the coil 27 can be increased and the electrical resistance can be lowered, and the efficiency of the motor is improved. Further, if the insulator 26 is formed by injection molding or compression molding, the insulator 26 can also serve to fix and support 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 aluminum wire having a round or square cross section is used. By supplying a current to the coil 27, an armature magnetic flux is generated from the stator 20, but as the number of turns increases and the current flowing through the coil 27 increases, the generated magnetic flux from the stator 20 increases. Therefore, it is preferable to reduce the resistance or increase the number of turns as much as possible. The larger the cross-sectional area of the coil 27 disposed in the slot 29, the better the motor performance.

  In the inner peripheral portion (inside) of the stator 20 as described above, the rotor 10 fitted to the shaft 18 is disposed with a gap between the rotor and the magnetic pole teeth 24. The gap G in the radial direction of the rotor 10 (hereinafter simply referred to as the radial direction) between the arc surface 244 and the rotor 10 is a predetermined value, and the radial gap between the plane 245 and the rotor 10 is opposite from the connection portion L. It gets bigger as you go further clockwise.

  Next, the angle θA, the angle θB, and the angle θα will be described. The angle θA is defined as an angle formed by the plane Fb connecting the connecting portion L and the shaft centerline E and the center plane Fa of the magnetic pole teeth 24. However, the center plane Fa of the magnetic pole teeth 24 is the shaft centerline E. It is assumed that you pass. Therefore, as described above, the angle θA and the angle θB are equal. Therefore, the angle θB is uniquely determined depending on how the angle θA is selected. Since the angle θA determines the width of the arc surface 244 concentric with the shaft center line E, the angle θA should be as large as possible in order to minimize the axial tilt of the magnetic pole teeth 24 during assembly. On the other hand, although the tilt is allowed to some extent, it is reduced, but from a practical point of view, the angle θA> = 0, that is, the connection portion L that is the end line in the counterclockwise direction of the circular arc surface 244 is at least counter to the center plane Fa. Set to be on the watch side.

  Next, how to determine 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 necessary 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 torque τn−minimum value of steady torque τn) / 2. Since the steady torque τn, the torque ripple τr, and the 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 each required specification. For example, when the moment of inertia of a load (for example, fan blades) attached to the single-phase brushless motor is large, the value of the angle θα is decreased so that the starting torque τs is increased. On the contrary, although the moment of inertia of the mounted load is small, when the load torque during operation is large, the value of the angle θα is increased so that the steady torque τn is increased. Since the torque ripple τr leads to vibration and noise, when low vibration and noise are required, the angle θα is selected to be small so that the torque ripple τr is small. In any case, the angle θA and the angle θα may be appropriately selected according to 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 from the tangential plane Fd of the arc surface 244 drawn from the connection portion L, the plane 245 and the core mold (refer to the core mold CC in FIG. 7), the arc surface 244 cannot be centered by contacting the core mold CC, and the arc surface when the divided stator piece 21 is assembled. It becomes difficult to ensure accuracy such as roundness and coaxiality of the inner circumference formed by H.244. Further, when the flat surface 245 comes out to the other end portion 248 side of the orthogonal flat surface Fc, the radial thickness of the shoe 243 becomes thin, resulting in a decrease in torque. If the plane 245 is within the range of the angle θB (0 = <θα <= θB), it is easy to achieve assembly accuracy and the torque is not reduced. Note that the arcuate surface 244 may be chamfered or rounded at the clockwise end in FIG. 2 or the counterclockwise end of the flat surface 245.

  Next, the characteristics of the single-phase brushless motor having such a configuration will be described in comparison with the conventional one. First, the single-phase brushless motor according to the first embodiment has a feature that the starting torque τs is larger than that of the conventional one. 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 in the first embodiment of the present invention. It is sectional drawing which shows the structure of this single phase brushless motor. 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 includes an insulator 26, a coil 27, a magnetic pole tooth 94, an annular yoke 98, and a slot 99. The magnetic pole teeth 94 protrude from the inner peripheral side of the annular yoke 98 at four locations. The magnetic teeth 94 have one end portion 941 and the other end portion 948 (indicated by phantom lines) on the opposite side. One end portion 941 has shoes 942 on both sides in the circumferential direction, and an arcuate surface 944 is formed. The arc surface 944 is an arc surface having a radius r <b> 1 centered on the shaft center line E of the rotor 10.

  Further, in one end portion 941, a groove portion 945 that forms a groove having a rectangular cross section at a position rotated counterclockwise by a predetermined angle from the center of the arcuate surface 944 (the shoe 942 on the counterclockwise side of the shoes on both sides). Is provided. The yoke 98 and the magnetic pole teeth 94 are formed by laminating a predetermined number of electromagnetic steel plates having a thickness of about 0.2 to 1.2 mm punched into a shape having an annular portion and projecting portions projecting inward from four locations of the annular portion. The yoke 98 and the magnetic pole teeth 94 are integrally formed. WJ is a nozzle for winding the coil 27 around the magnetic pole teeth 94, and shows a state when the coil 27 is wound around the magnetic pole teeth 94. Since other configurations are the same as those of the first embodiment shown in FIG. 1, the same reference numerals are given to the corresponding components and the description thereof is omitted.

  The single-phase brushless motor configured as described above can reduce the peak of cogging torque by providing a groove 945 at one end of the magnetic pole teeth 94. By the way, unlike a case of a single-phase brushless motor in which alternating currents having different phases are passed through a plurality of magnetic pole teeth, such as 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 the single-phase brushless motor having such a configuration, there is a point where the torque becomes zero. In addition, when the number of poles is small (in the case of four poles as in the present embodiment, etc.), generally, the gap between the shoes 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 point where the magnetic teeth and the magnetic pole center of the rotor coincide with each other, the magnetic poles of the magnetic teeth and the permanent magnet of the rotor attract strongly in the radial direction. In this respect, when the rotor is stationary, there is a problem in that it is necessary to control the DC current applied at the start in a complicated manner 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 according to 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 represents the rotation angle deg of the rotor 10 and the vertical axis represents the torque. FIG. 6 is a partially enlarged view of FIG. In these drawings, the position where the rotation angle deg on the horizontal axis is 0 is a 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 a conventional single-phase brushless motor 900. A curve a1 in the graph is a steady torque when an alternating current is applied, a curve b1 is a cogging torque, and a curve. c1 indicates a starting torque when a direct current is applied (a direct current is applied at the time of starting). A point representing the starting torque, which is a torque at a position where the cogging torque becomes 0 on the curve c1, is denoted by p1, and is indicated by a ◇ mark in the figure. FIG. 5B and FIG. 6B show the characteristics of the single-phase brushless motor 100 in the present embodiment. A curve a2 in the graph is a steady torque when an alternating current is applied, and a curve b2 is cogging. A torque curve c2 indicates a starting torque that is a torque when a direct current is applied. A point representing the starting torque, which is a torque at a position where the cogging torque is 0 on the curve c2, is denoted by p2, and is indicated by a ◇ mark in the figure.

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

  In the conventional single-phase brushless motor, although the pulling force at the position of the groove portion 945 is weakened, the shoe 942 provided with the groove portion 945 has the same gap between the shoe 942 and the rotor 10 on both sides in the circumferential direction of the groove portion 945. Since the shoe 942 and the magnetic pole 12 of the rotor 10 are attracted both on the clockwise side and the counterclockwise side across the groove 945, the position where the cogging torque becomes 0 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 according to the present embodiment, the gap between the arc surface 244 and the flat surface 245 that are opposed to the rotor 10 of the magnetic teeth 24 gradually increases in the counterclockwise direction with the connection portion L as a boundary. The gap becomes the largest at the end of the shoe 243 on the counterclockwise side. Therefore, the force attracted by the magnetic teeth 24 and the magnetic pole 12 of the rotor 10 gradually increases in the clockwise direction from the counterclockwise direction of the shoe 243 in FIG. 2, and the position (that is, the position where the cogging torque becomes 0). ) Deviates more in the clockwise direction than the center plane Fa of the magnetic pole teeth 24. As the position at which the cogging torque becomes 0 deviates from the center plane Fa of the magnetic pole teeth 24, it becomes easier to obtain the starting torque.

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

  On the other hand, in the conventional single-phase brushless motor 900 of FIG. 4, since the magnetic teeth 94 and the annular yoke 98 are integrated as shown in FIG. 4, the winding nozzle WJ is inserted from the inner peripheral side and the coil 27 is inserted. Need to be wound. As a result, a space for the winding nozzle WJ to enter the slot 99 must be secured, and as a result, the cross-sectional area (number of turns) of the coil must be smaller than that of the single-phase brushless motor 100 of FIG. . That is, the single-phase brushless motor 100 of the present embodiment has a large cross-sectional area of the coil 27 and can reduce copper loss compared to the conventional one. In addition, since the conventional one has the groove portion 945, the thickness of the shoe 943 in the vicinity of the groove portion 945 (the radial dimension of the stator 90) is small, and the magnetic flux density locally increases in the portion, thereby increasing the iron loss. . 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 is not locally increased, and compared with the conventional single-phase brushless motor. 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, and has a low copper loss and a low iron loss, and can be highly efficient.

  Such a single-phase brushless motor 100 can be used for any application. For example, it is suitable for a drive source of a small household electric product such as a vacuum cleaner that needs to arrange a motor or a drive circuit in a limited space. Since the single-phase drive type motor has a small number of phases, the configuration of the drive circuit can be made simple and small, 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, the coil 27 is wound around the magnetic pole teeth 24, and then the yoke piece 23 is magnetically connected by the yoke coupling piece 28, and the rotor 10 is accommodated by the arc surfaces 244 of the plurality of stator pieces 21. Must be assembled so that a cylindrical part is formed. Hereinafter, an accurate assembly method will be described. First, the coil 27 is wound around the magnetic teeth 24 to prepare four stator pieces 21. Next, as shown in FIG. 7, a core CC as an assembly jig is arranged at the center. The core type CC is a cylindrical shape having a diameter obtained 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 teeth 24 to bring the arc surface 244 into contact with the core CC, and in this state, the yoke coupling piece 28 is brought into contact with each yoke piece 23. Center alignment of the arc surface 244 and circumferential alignment of the stator piece 21 are performed. In this way, the center line of the arc surface 244 of the plurality of magnetic teeth 24 and the shaft center line E (see FIG. 2) can be accurately aligned, and the arc surface 244 of the magnetic teeth 24 is formed. It is possible to ensure the roundness of the cylindrical surface. Thereby, stable starting torque can be obtained, and vibration and noise when the single-phase brushless motor rotates can be suppressed.

  As a more preferable example, the angle θA formed between the plane Fb shown in FIG. 2 and the center plane Fa of the magnetic pole teeth 24 is set to be positive (the counterclockwise direction is positive). Thus, when assembling each stator piece 21, the length of the arc of the arc surface 244 to be brought into contact with the core CC can be increased, and the stator piece 21 is unlikely to fall down and can be assembled with high accuracy.

Embodiment 2. FIG.
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 connects the yoke piece 23 and the yoke coupling piece 28 of the stator piece 21 so as to be bendable by plastic deformation. 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 can be bent by plastic deformation. The core piece 22 and the yoke coupling piece 28 can be closed or opened with the connecting portion 55 as an axis. The core piece 22 having the yoke piece 23 and the magnetic pole teeth 24 and the yoke coupling piece 28 are the stator core in this embodiment. Since other configurations are the same as those of the first embodiment shown in FIG. 1, the same reference numerals are given to the corresponding components and the description thereof is omitted.

  When the coil 27 is wound around the magnetic teeth 24, the core piece 22 is opened and wound. Therefore, like the first embodiment, the coil 27 can be easily wound and the coil area can be increased. When assembling, similarly to the first embodiment, the arcuate 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, as in the first embodiment, 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. The roundness of the cylindrical surface formed by the arc surface 244 can be ensured. Therefore, stable starting torque can be obtained, and vibration and noise when the single-phase brushless motor rotates can be suppressed. Furthermore, the core piece 22 can be handled integrally in a state where the core piece 22 is connected by the connecting portion 55, and transportation and handling in the production line becomes easy.

Embodiment 3 FIG.
FIG. 9 shows the configuration of the stator of the single-phase brushless motor according to the third embodiment. FIG. 9A is a cross-sectional view in 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 teeth 64 have the other end 648 exposed as shown in FIG. The insulator assembly 67 has an insulator assembly 67 as an insulation member assembly, and the insulator assembly 67 accommodates and holds four magnetic teeth 64 corresponding to one single-phase brushless motor, respectively. 66 is integrally formed of insulating resin, for example. The insulator 66 has a cylindrical portion 66a having a rectangular cross section, and the magnetic pole teeth 64 are accommodated in the cylindrical portion 66a as shown in FIG. 9A, and the coil 27 is disposed on the outer peripheral portion of the cylindrical portion 66a. Is wound. Therefore, in a 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 formed integrally. The magnetic pole teeth 64 and the yoke 68 are the stator core in this embodiment. Since other configurations are the same as those of the first embodiment shown in FIG. 1, the same reference numerals are given to the corresponding components and the description thereof is 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 by the arc surface 244 of the magnetic pole teeth 64 with all the magnetic pole teeth 64 inserted is slightly larger than the diameter of the core CC. Then, the core CC is inserted with all the magnetic teeth 64 inserted, and the four magnetic teeth 64 are positioned by bringing the arc surface 244 of the magnetic pole teeth 64 into contact with the core CC. Next, a winding machine is placed on the side of the magnetic teeth 64 and the coil 27 is wound around the insulator 66. Thereafter, the yoke 68 is inserted from a direction perpendicular to the paper surface of FIG. 9A and fixed integrally with the magnetic pole teeth 24. Note that the fixing method may be any joining method such as press-fitting, shrink fitting, adhesion, and welding. Alternatively, after the coil 27 is wound around the insulator 66, the magnetic pole teeth 64 may be sequentially inserted and held in the insulator 66.

  The magnetic pole teeth 64 divided in this way can be held together by the insulator assembly 67, so that the handling until the magnetic pole teeth 64 is fixed to the yoke 68 becomes easy. Moreover, the operation | work which winds the coil 27 for 4 poles, and the operation | work which connects the coil 27 mutually become easy. Two insulator assemblies 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 arc surface 244 and the shaft center line E of the magnetic pole teeth 64 as in the first embodiment. The roundness of the cylindrical surface formed by the arc surface 244 can be ensured. Therefore, stable starting torque can be obtained, and vibration and noise when the single-phase brushless motor rotates can be suppressed.

  In each of the embodiments described above, the rotor 10 having the cylindrical permanent magnet 11 in which the magnetic poles are integrally formed is shown. However, the rotor 10 is constituted by a plurality of permanent magnets divided for each magnetic pole. Also good. Moreover, when using the some permanent magnet divided | segmented for every magnetic pole, the yoke body which connects the magnetic poles formed with a permanent magnet may be provided.

  The permanent magnet 11 forming the rotor 10 is a hard magnetic material having a coercive force higher than that of the soft magnetic material. The permanent magnet 11 may be of any kind, for example, a ferrite bonded magnet (residual magnetic flux density (Br) 0.2 to 0.3 T) composed of ferrite magnetic powder and resin, or a ferrite sintered magnet (Br 0.35 to 0. 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 force, 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 increases. In addition, when used at a high temperature, a ferrite magnet that does not demagnetize at a high temperature or a neodymium sintered magnet with a high coercive force is desirable.

  The shaft 18 may be a soft magnetic material or a nonmagnetic material. Examples of the soft magnetic material include steel materials such as carbon steel for mechanical structure S10C and SS400 defined in Japanese Industrial Standards, and examples of the nonmagnetic material include stainless steel (SUS). Further, these materials may be quenched to increase the strength.

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

  In addition, as described above, when manufacturing a single-phase brushless motor, the magnetic pole teeth can be positioned quickly and accurately by positioning the magnetic pole teeth by contacting the arc surface of the magnetic pole teeth to the core mold. It is possible to provide a method for manufacturing a single-phase brushless motor that can obtain a starting torque, can suppress vibration and noise when rotating, and can easily assure assembly accuracy.

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

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 disposed on the outside rotates. Even if it is a thing, there exists the same effect.
In the present invention, the above-described embodiments can be freely combined within the scope of the invention, and each embodiment can be appropriately changed or omitted.

10 rotor, 11 permanent magnet, 12 magnetic pole, 20 stator, 21 stator piece,
22 core pieces, 23 yoke pieces, 24 magnetic teeth, 27 coils,
28 Yoke coupling piece, 50 stator, 55 connecting part, 61 stator piece,
64 magnetic teeth, 66 insulator, 67 insulator assembly,
68 yoke, 94 magnetic teeth, 100 single-phase brushless motor,
200 single-phase brushless motor, 241 end, 244 arc surface, 245 plane,
248,648 end.

Claims (10)

A single-phase brushless motor having a rotor and a stator,
The rotor is cylindrical 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 teeth have one end and the other end, and the one end has an arcuate surface and an adjacent surface formed by connecting the arcuate surface and the connecting portion, and the adjacent surface is A plane or curved surface formed so as to be positioned closer to the other end than a virtual arc surface extended with the same curvature as the arc surface from the connecting portion between the arc surface and the adjacent surface. ,
The coil is wound around the magnetic pole teeth,
The magnetic pole teeth are arranged so that the arc surface is opposed to the rotor with a certain gap in the radial direction of the rotor, and the radial gap between the adjacent surface and the rotor increases as the distance from the arc surface increases. A single-phase brushless motor in which the adjacent surface is arranged to face the rotor and the other end is magnetically coupled to the yoke. The said adjacent surface is formed so that it may be located in the same position as the tangent plane of the said circular arc surface in the said connection part, or a position far from the said virtual circular arc surface rather than the said tangential plane. Single phase brushless motor. The adjacent surface is formed so as to be located at a position that is the same as an orthogonal plane that passes through the connecting portion and is orthogonal to the center plane of the magnetic pole teeth, or closer to the virtual arc surface than the orthogonal plane. The single-phase brushless motor according to claim 1 or 2. 4. The single-phase brushless according to claim 1, wherein the stator core is configured by combining the magnetic pole teeth and a plurality of core pieces having yoke pieces corresponding to the magnetic pole teeth. 5. motor. The single-phase brushless motor according to claim 4, wherein the core piece is formed by integrally forming the magnetic pole teeth and the yoke piece. The single-phase brushless motor according to claim 4, wherein the stator core has a yoke coupling piece that magnetically couples the yoke piece. The single-phase brushless motor according to any one of claims 4 to 6, wherein the stator core is configured such that the plurality of stator pieces are connected to each other so as to be bendable. 4. The single-phase brushless according to claim 1, wherein the stator core is configured by combining a plurality of the magnetic teeth formed separately from the yoke and the yoke. 5. motor. The method for manufacturing a single-phase brushless motor according to any one of claims 4 to 8, wherein the arc surface of the magnetic pole teeth is brought into contact with a cylindrical assembly jig to position the magnetic pole teeth. A method for manufacturing a single-phase brushless motor, which includes a step of combining. 9. The method of manufacturing a single-phase brushless motor according to claim 8, wherein a step of manufacturing an insulating member assembly having a plurality of insulating members, a step of holding the magnetic pole teeth on the insulating members, and a cylindrical assembly And a step of bringing the arc surface of the magnetic pole teeth into contact with a jig to align the magnetic pole teeth.

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