JP2007104740A - Brushless motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brushless motor in which the cost can be reduced by reducing assembling man-hour. <P>SOLUTION: Stator 29 of a brushless motor 1 comprises a flux plate 9 provided on a base member 3, a circuit board 13 provided on a flux plate 9, only one coil 23 provided on the circuit board 13, a Hall element provided on the circuit board 13 in order to detect magnetism of magnets 34-37 of the rotor 19, a drive IC 27 provided on the circuit board 13 in order to control a current supplied to the coil 23, and a weight 39 provided on the rotor 19 out of balance. The rotor 19 is provided with magnets 34-37 of quadrupole and rotates about a shaft 15 supported on the base member 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention particularly relates to a brushless motor used as a vibration motor or a fan motor.

Conventionally, as a technique in such a field, a brushless motor described in Patent Document 1 below is known. The brushless motor described in this document includes a stator having a circuit board provided with two coils and a rotor having a 6-pole magnet.
JP 2003-88805 A

  By the way, in this kind of brushless motor, it is required to reduce the number of assembly steps in order to reduce the cost. Accordingly, an object of the present invention is to provide a brushless motor that can reduce assembly man-hours and reduce costs.

  A brushless motor according to the present invention is provided on a base member in a brushless motor that detects the magnetism of a magnet provided in a rotor and rotates the rotor while controlling the current supplied to the coil based on the detected magnetism. A stator having a flux plate, a circuit board provided on the flux plate, a coil provided only on the circuit board, and a Hall element provided on the circuit board for detecting magnetism of the magnet; A magnet having four poles magnetically arranged NS alternately at a position facing the coil, a rotor rotating about a shaft supported by the base member, a circuit board and a circuit board A motor drive element that controls the current supplied to the coil, located between the rotor and the rotor. A weight to be kicked, and further comprising a.

  This brushless motor rotates a rotor provided with a magnet while controlling a current supplied to a coil provided in the stator. And since this brushless motor is provided with the weight provided in the rotor unbalanced, it comprises the vibration motor which generate | occur | produces a vibration by rotating a rotor. The stator of this brushless motor is provided with a Hall element that detects the magnetism of the rotating rotor magnet, and the control of the current supplied to the coil for generating the rotation of the rotor is detected by this Hall element. This is done based on magnetism. The brushless motor has only one coil provided on the stator. According to such a configuration, in addition to the reduction in the number of parts due to the reduction in the number of coils, the routing of the wiring to the coil becomes much simpler than in the case of a plurality of coils, so that the number of coils is reduced to one. The assembly man-hours required are very large. Therefore, the cost of the brushless motor can be reduced by using a single coil.

  Also, in a motor with a brush in which a coil is generally provided not on the stator side but on the rotor side, if one coil is used, the weight balance of the rotor can be balanced with an even arrangement of coils. Therefore, it becomes difficult to set the center of gravity of the rotor in order to obtain a uniform rotation of the rotor. On the other hand, in the case of a brushless motor in which the coil is provided on the stator side, the number of coils can be made one without considering the position of the center of gravity of the rotor. This is effective in a simple brushless motor.

  The brushless motor includes a motor driving element that is provided on the circuit board and controls a current supplied to the coil. Thus, by providing the motor driving element on the circuit board, the convenience when using the motor is improved as compared with the case where the driving circuit is provided outside the motor. In addition, since the free space on the circuit board is widened by the configuration having only one coil, it is easy to secure a place for installing the motor driving element. Further, the motor driving element is provided between the circuit board and the rotor. With such a configuration, the motor driving element can be installed on the circuit board using a space corresponding to the thickness of the coil, so that the motor can be miniaturized by effectively using the space.

  The brushless motor according to the present invention is a brushless motor that detects the magnetism of a magnet provided in a rotor and rotates the rotor while controlling the current supplied to the coil based on the detected magnetism. A flux plate provided; a circuit board provided on the flux plate; a coil provided only on the circuit board; and a hall element provided on the circuit board for detecting magnetism of the magnet. A stator, a magnet having four magnetic poles NS alternately arranged at a position facing the coil, a rotor rotating around a shaft supported by a base member, a circuit board and a circuit are provided. A motor driving element that is located between the substrate and the rotor and controls the current supplied to the coil, and is provided on the rotor. Characterized by comprising a vane for generating a wind, a by rotation of the rotor.

  This brushless motor rotates a rotor provided with a magnet while controlling a current supplied to a coil provided in the stator. And this brushless motor is provided with the blade | wing which is provided in a rotor and generates a wind by rotation of a rotor, Therefore The fan motor which generates a wind is comprised. The stator of this brushless motor is provided with a Hall element that detects the magnetism of the rotating rotor magnet, and the control of the current supplied to the coil for generating the rotation of the rotor is detected by this Hall element. This is done based on magnetism. The brushless motor has only one coil provided on the stator. According to such a configuration, in addition to the reduction in the number of parts due to the reduction in the number of coils, the routing of the wiring to the coil becomes much simpler than in the case of a plurality of coils, so that the number of coils is reduced to one. The assembly man-hours required are very large. Therefore, the cost of the brushless motor can be reduced by using a single coil.

  Also, in a motor with a brush in which a coil is generally provided not on the stator side but on the rotor side, if one coil is used, the weight balance of the rotor can be balanced with an even arrangement of coils. Therefore, it becomes difficult to set the center of gravity of the rotor in order to obtain a uniform rotation of the rotor. On the other hand, in the case of a brushless motor in which the coil is provided on the stator side, the number of coils can be made one without considering the position of the center of gravity of the rotor. This is effective in a simple brushless motor.

  The brushless motor includes a motor driving element that is provided on the circuit board and controls a current supplied to the coil. Thus, by providing the motor driving element on the circuit board, the convenience when using the motor is improved as compared with the case where the driving circuit is provided outside the motor. In addition, since the free space on the circuit board is widened by the configuration having only one coil, it is easy to secure a place for installing the motor driving element. Further, the motor driving element is provided between the circuit board and the rotor. With such a configuration, the motor driving element can be installed on the circuit board using a space corresponding to the thickness of the coil, so that the motor can be miniaturized by effectively using the space.

  According to the present invention, in a brushless motor, the number of assembling steps can be reduced and the cost can be reduced.

  Hereinafter, preferred embodiments of a brushless motor according to the present invention will be described in detail with reference to the drawings.

(First embodiment)
As shown in FIGS. 1-3, the brushless motor 1 of this embodiment comprises the small brushless vibration motor accommodated in apparatuses, such as a mobile telephone. The brushless motor 1 has a base member 3 having a mounting surface 3a to be mounted on a mounting board (not shown) of the device and a component mounting surface 3b facing the mounting surface 3a. Further, the brushless motor 1 has a cover 7 that constitutes a housing 5 together with the base member 3. The base member 3 and the cover 7 are made of a material such as plastic or fiber reinforced plastic (FRP, GFRP, CFRP), for example, and have a substantially square outer shape. And this housing | casing 5 has a magnitude | size of 11 mm long x 11 mm wide x 3.6 mm in height, for example, and size reduction is achieved.

  A flux plate 9 is fixed on the component mounting surface 3b of the base member 3. The flux plate 9 is formed of, for example, a silicon steel plate and has a function of smoothing the start-up of the motor 1. The flux plate 9 is arranged so that the center thereof coincides with the center of the component mounting surface 3b. The flux plate 9 is formed with a pair of notches 9a and 9b having a sector shape with a central angle of 90 ° at positions symmetrical to each other across the center. Further, the circuit board 13 supported on the component mounting surface 3 b of the base member 3 is fixed so as to cover the flux plate 9. The circuit board 13 has a substantially square outer shape, and has the same size as the base member 3. The circuit board 13 is formed of a flexible wiring board or the like, and wiring is printed on the upper surface.

  A flat coil 23 is fixed on the circuit board 13. Further, on the circuit board 13, a Hall element 25 for detecting magnetism, a driving IC (motor driving element) 27, and other electronic components are mounted. The drive IC 27 supplies current to the coil 23 while controlling the current based on the electrical signal from the hall element 25. Since such a drive IC 27 is provided on the circuit board 13, it is more convenient during use than when a drive circuit for supplying power to the coil 23 is separately provided outside the motor 1. In the brushless motor 1, since only one coil 23 exists on the circuit board 13, there is a sufficient space on the circuit board 13, and the installation place of the drive IC 27 can be easily secured.

  Further, shaft holding portions 3d and 7d each having a circular recess are provided at the center of the base member 3 and the center of the cover 7, respectively. The shaft 15 is fixed to the housing 5 by holding both ends of the shaft 15 having a circular section in the shaft holding portions 3d and 7d. The shaft 15 rotatably supports the rotor 19 via the radial bearing 17. The housing 5, the flux plate 9, the circuit board 13, the shaft 15, the coil 23, the hall element 25, and the driving IC 27 are described above. Constitutes a stator 29 for rotating the rotor 19.

  The positional relationship among the components of the flux plate 9, the coil 23, the Hall element 25, and the drive IC 27 in the stator 29 is as follows. In order to explain this positional relationship, as shown in FIG. 2, the direction of the edge 9e forming the notch 9a of the flux plate 9 as viewed from the shaft 15 is defined as a “reference direction A”. It shall represent the direction of each part viewed. In this case, the coil 23 has the centers of both end portions 23a and 23b of the coil 23 in the direction of 115 ° (direction B) and the direction of 202.5 ° (direction C) clockwise from the reference direction A, respectively. Are arranged as follows. The Hall element 25 is arranged so as to exist in a direction (direction D) of 22.5 ° clockwise from the reference direction A, and the drive IC 27 is a direction of 67.5 degrees counterclockwise from the reference direction A. It arrange | positions so that it may exist in (direction E).

  The rotor 19 that rotates with respect to the stator 29 described above has a rotating disk 33 having a diameter of about 8 mm that is rotatably supported by the shaft 15 via the radial bearing 17. Four magnets 34, 35, 36, and 37 are fixed to the surface of the rotating disk 33 that faces the circuit board 13. Of these four magnets, the magnets 34 and 36 are magnetized so that the surface on the side facing the circuit board 13 is an N pole, and the surfaces of the magnets 35 and 37 on the side facing the circuit board 13 are the S poles. Is magnetized. Thus, the four magnets 34 to 37 each formed in a sector shape with a central angle of 90 ° are arranged in the circumferential direction around the shaft 15 to constitute a so-called four-pole magnet.

  In addition, a half-moon-shaped weight 39 made of a material with a high specific gravity such as sintered tungsten is eccentrically fixed to the rotating disk 33 in order to make the weight distribution of the rotor 19 around the shaft 15 uneven. ing. When the rotor 19 provided with such a weight 39 rotates, the brushless motor 1 functions as a vibration motor for generating vibration.

  Based on the above configuration, when a current is supplied from the driving IC 27 to the coil 23, a radial current in the rotor 19 is generated at the end portions 23 a and 23 b of the coil 23. Due to this radial current, a circumferential electromagnetic force acts on the magnets 34 to 37, and the rotor 19 rotates around the shaft 15 by this electromagnetic force. And according to the positional relationship between the coil 23 and the Hall element 25 as described above, at the same timing as the magnets 34 to 37 at the positions of the end portions 23a and 23b of the coil 23 are switched during the rotation of the rotor 19. The magnets 34 to 37 at the position of the hall element 25 are also replaced. That is, at this time, the magnetic field generated at the positions of the end portions 23a and 23b of the coil 23 is reversed by the magnets 34 to 37, and the pole of the magnet detected by the Hall element 25 is reversed at the same timing. Therefore, the power supply to the coil 23 by the drive IC 27 is controlled so as to invert the current supplied to the coil in accordance with the reversal timing of the pole detected by the Hall element 25, so that the magnets 34 to 37 are always provided. The electromagnetic force in the same direction works, and the rotor 19 is continuously rotated by this electromagnetic force.

  The torque obtained with such a brushless motor 1 is shown in FIG. In FIG. 4, the graph shown by the line T <b> 1 shows the torque T <b> 1 resulting from the force obtained at the ends 23 a and 23 b of the coil 23, and the line T <b> 2 shows the interaction between the flux plate 9 and the magnets 34 to 37. The cogging torque T2 is shown. The diagram T3 shows the torque that is actually output from the motor 1 by combining the torque T1 and the torque T2. As shown in FIG. 4, even with the brushless motor 1 having only one coil 23, there is no problem torque characteristics, and no problem rotation is obtained.

  When the rotor 19 is stopped, one of the boundary lines between the magnets 34 to 37 is rotated clockwise from the reference direction A to a direction F of 45 ° by the interaction between the flux plate 9 and the magnets 34 to 37. Will stop. In such a stopped state, the boundary lines of the magnets 34 to 37 which are dead points are not stopped at the positions of the end portions 23 a and 23 b of the coil 23. The rotor 19 starts to rotate smoothly.

  As described above, since the brushless motor 1 has only one coil, in addition to the reduction in the number of parts due to the reduction in the number of coils, the routing of the wiring to the coil becomes much simpler than in the case of a plurality of coils. . Therefore, in such a brushless motor 1, the number of assembling steps can be greatly reduced, and the cost can be reduced.

  In a motor with a brush, in which a coil is generally provided not on the stator side but on the rotor side, if one coil is used, the weight balance of the rotor can be balanced by evenly arranging the coils. Therefore, it becomes difficult to set the center of gravity of the rotor in order to obtain a uniform rotation of the rotor. On the other hand, in the case of the brushless motor 1, since the coil is provided on the stator 29 side, the coil 23 can be made one without considering the position of the center of gravity of the rotor 19. That is, the configuration with one coil is effective only in a brushless motor such as the motor 1.

  Further, as described above, the drive IC 27 is built in the brushless motor 1 for the sake of convenience. However, since there is sufficient free space on the circuit board 13 due to the configuration with one coil, The installation location of the drive IC 27 can be easily secured. Further, the drive IC 27 is disposed between the circuit board 13 and the rotor 19 using a space corresponding to the thickness of the coil 23, and the brushless motor 1 can be reduced in size by effectively using such a space. It is illustrated. Further, since the brushless motor 1 employs a four-pole magnet, the mounting position accuracy of the Hall element 25 is relaxed compared to the case of using a six-pole or eight-pole magnet, and power is supplied to the coil 23 by the drive IC 27. It becomes easy to control.

(Second Embodiment)
As shown in FIG. 5, in the brushless motor 51 of the present embodiment, the rotating disk 55 of the rotor 53 is fixed to the shaft 57. The shaft 57 is supported via a bearing 59 so as to be rotatable with respect to the bearing holding portion 61 a of the base member 61. Based on such a configuration, the shaft 57 rotates integrally with the rotor 53, and vibration is generated by the weight 39 provided on the rotor 53. In addition, in this brushless motor 51, about the structure same or equivalent to the brushless motor 1, the same code | symbol is attached | subjected to drawing and the description is abbreviate | omitted.

(Third embodiment)
As shown in FIG. 6, in the brushless motor 71 of the present embodiment, the rotor 73 has blades 75 instead of the weights 39. A plurality (for example, five) of the blades 75 are arranged at equal intervals in the rotation direction of the rotor 73, and are fixed to the rotation disk 77 of the rotor 73, and from the outer periphery of the rotation disk 77 in the radial direction. It is approaching. Such blades 75 rotate together with the rotor 73 and the shaft 57 to generate wind that flows in a direction perpendicular to the rotation direction. That is, the rotor 73 having such blades 75 functions as a fan that generates wind by rotation.

  Further, a vent hole 85 is formed in the cover 79 and the base member 83 at a position corresponding to the blade 75. The wind generated by the rotation of the rotor 73 passes through the ventilation port 85 and flows to the outside of the brushless motor 71. That is, the brushless motor 61 functions as a fan motor. In addition, in the brushless motor 61, about the structure same or equivalent to the brushless motors 1 and 51, the same code | symbol is attached | subjected to drawing and the description is abbreviate | omitted.

It is sectional drawing which shows 1st Embodiment of the brushless motor which concerns on this invention. It is a top view which shows the stator of the brushless motor shown in FIG. It is a top view of the state which attached the rotor to the stator of FIG. It is a graph which shows the relationship between the rotor rotation angle and generated torque in the brushless motor of FIG. It is sectional drawing which shows 2nd Embodiment of the brushless motor which concerns on this invention. It is sectional drawing which shows 3rd Embodiment of the brushless motor which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,51,71 ... Brushless motor, 3, 61, 83 ... Base member, 9 ... Flux plate, 13 ... Circuit board, 15, 57 ... Shaft, 19, 53, 73 ... Rotor, 23 ... Coil, 25 ... Hall element 27 ... Drive IC (element for driving motor), 29 ... Stator, 34-37 ... Magnet, 39 ... Weight (weight), 75 ... Vane.

Claims (2)

In the brushless motor that detects the magnetism of the magnet provided in the rotor and rotates the rotor while controlling the current supplied to the coil based on the detected magnetism,
A flux plate provided on a base member, a circuit board provided on the flux plate, only one coil provided on the circuit board, and a magnet of the magnet provided on the circuit board. A stator having a Hall element for detecting
The rotor having four magnetic poles NS alternately arranged at a position facing the coil, the rotor rotating about a shaft supported by the base member;
A motor driving element that is provided on the circuit board and located between the circuit board and the rotor and controls a current supplied to the coil;
A brushless motor comprising: a weight provided on the rotor in an unbalanced manner. In the brushless motor that detects the magnetism of the magnet provided in the rotor and rotates the rotor while controlling the current supplied to the coil based on the detected magnetism,
A flux plate provided on a base member, a circuit board provided on the flux plate, only one coil provided on the circuit board, and a magnet of the magnet provided on the circuit board. A stator having a Hall element for detecting
The rotor having four magnetic poles arranged alternately with NS at a position facing the coil is provided, and the rotor rotates around a shaft supported by the base member;
A motor driving element that is provided on the circuit board and located between the circuit board and the rotor and controls a current supplied to the coil;
A brushless motor, comprising: a blade provided on the rotor and generating wind by rotation of the rotor.

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