JP2006101601A - Vibration motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration motor for maintaining an activation performance and increasing the quantity of vibration. <P>SOLUTION: In the vibration motor 1, a flat rotor 30 has one coil 33 embedded in a frame 32 and is rotatably received on a magnet 11 in a case C, and a magnetic material 36 makes the rotor 30 stop in an activation position when the rotor 30 is in a stationary state and is embedded in the frame 32 outside the coil 33. The frame 32 is provided with a nonmagnetic weight 37 between the magnetic material 36 and the coil 33. In the vibration motor 1, the rotor 30 is rotated and the case C is vibrated by carrying a current to the coil 33. Since the weight 37 is provided, the quantity of vibration is increased. Since the weight 37 is nonmagnetic, the magnetic material 36 surely regulates the stationary position of the rotor 30, the activation performance can be maintained, and the quantity of vibration can be increased without an influence by the weight 37 if the weight 37 is adopted. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vibration motor incorporated in various mobile communication devices (for example, mobile phones) and used as a vibration generation source.

  A mobile phone has a built-in vibration motor as a vibration source for notifying incoming calls. In recent years, the vibration motor has been reduced in size, and a single-phase flat type has been frequently used. As such a single-phase flat-type vibration motor, there is one described in Patent Document 1. The vibration motor described in this publication has a substantially cylindrical case, and a flat rotor in which coils are embedded in a frame, and N and S poles are alternately arranged in the case. An annular magnet is accommodated, and the rotor is rotatably arranged above the magnet fixed to the inner surface of the case. Then, when a current is passed through the coil, the rotor rotates and the case vibrates.

In a single-phase motor, the current is supplied to the coil via a commutator electrically connected to the coil, and the direction of the current flowing through the coil is switched by the commutator in accordance with a change in magnetism. . Therefore, when the vibration motor is stopped, if the rotor is stationary at the current switching position, a start error occurs. In view of this, in the vibration motor, the frame is provided with a magnetic pin that restricts the stationary position of the rotor so that the rotor comes to the startable position when the coil is not energized.
Japanese Patent Laid-Open No. 10-336983

  By the way, since the vibration motor is used to notify the incoming call of the mobile phone as described above, the vibration motor is required to have a sufficiently high vibration as the incoming call notification while being reduced in size. In order to obtain this high vibration, in the conventional vibration motor, the amount of eccentricity of the rotor is increased by adjusting the arrangement of the coils in the frame. It has also been proposed to place a weight inside the coil. However, it has been difficult to obtain a sufficient amount of vibration that can meet the requirements only by adjusting the arrangement of the coils. In addition, when a weight is provided, if the weight has magnetism, the stationary position of the rotor is also restricted by the weight, resulting in a decrease in the function of the magnetic pin and a rotor start error. was there.

  Therefore, an object of the present invention is to provide a vibration motor in which the amount of vibration is increased while maintaining the starting performance.

  In order to solve the above-mentioned problems, a vibration motor according to the present invention includes a flat rotor in which one coil is embedded in a frame and is rotatably accommodated on a magnet in a case. In a vibration motor in which a magnetic body for resting at a startable position is embedded in the frame outside the coil, the frame is provided with a non-magnetic weight between the magnetic body and the coil. And

  In this configuration, when the current flows through the coil, the rotor rotates and the case vibrates. When the rotor rotates, the weight provided on the frame increases the amount of eccentricity of the rotor, so that high vibration can be obtained. Since the weight is arranged between the coil and the magnetic body, it is easy to select the size and shape of the weight effective for increasing the amount of eccentricity of the rotor. A configuration is obtained. Further, since the weight is non-magnetic, the stationary position of the rotor is surely restricted to the startable position by the magnetic body embedded in the frame outside the coil without being affected by the weight. As a result, even when a weight is employed, the amount of vibration can be increased while maintaining the starting performance of the vibration motor.

  Moreover, it is preferable that the rotor of the vibration motor according to the present invention has a disk shape. In this case, since a larger weight can be arranged, the amount of eccentricity of the rotor can be further increased, and as a result, high vibration can be obtained.

  According to the vibration motor of the present invention, the vibration motor can be started smoothly and high vibration can be obtained.

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

  As shown in FIGS. 1 and 2, the vibration motor 1 has a substantially cylindrical case C composed of a disk-shaped metal base plate 10 and a metal cylindrical cover 20. The flat rotor 30 is accommodated. The vibration motor 1 is a single-phase motor and is downsized to have a diameter of about 10 mm and a height of about 3 mm. The vibration motor 1 is built in a mobile phone and used as a vibration source.

  An annular magnet 11 is bonded and fixed on the base plate 10. The magnet 11 is equally divided into four regions, magnetized in a direction substantially perpendicular to the upper surface of the base plate 10, and N poles 11a and 11c and S poles 11b and 11d are alternately arranged. Yes.

  A support shaft 12 that rotatably supports the rotor 30 is disposed in the center of the base plate 10. The support shaft 12 is press-fitted into a boss portion 13 formed in the center of the base plate 10, for example. It is fixed. A flexible substrate 14 is arranged on the base plate 10 so as to surround the boss portion 13. The flexible substrate 14 has a pair of terminals 14b and 14c embedded in an insulating substrate 14a. A portion of the flexible substrate 14 is connected to the peripheral wall 10a of the base plate 10 in order to connect to an external power source (not shown). It protrudes outward from the formed notch.

  Then, one end of the pair of terminals 14b and 14c is exposed from the board 14a to the protruding portion, and is electrically connected to an external power source. The other ends of the pair of terminals 14b and 14c are joined to the base ends of the pair of brushes 15a and 15b disposed around the boss portion 13 by solder. Thereby, electric power can be supplied to the pair of brushes 15a and 15b from the external power source. Further, the free ends of the pair of brushes 15a and 15b protrude from the flexible substrate 14 toward the rotor 30 in order to ensure sliding contact with the commutator 31 (see FIGS. 2 and 3) of the rotor 30. . The free end of the brush 15a is located near the boundary between the N pole 11a and the S pole 11b, and the free end of the brush 15b is located near the boundary between the S pole 11b and the N pole 11c.

  The rotor 30 has a disk-shaped frame 32 made of resin, and an air-core coil 33 is integrally embedded in the frame 32, and a substantially cylindrical bearing to be the rotation center of the rotor 30. 34 is embedded. The rotor 30 is rotatably supported by the support shaft 12 via a bearing 34.

  Since the bearing 34 extends toward the lower side (base plate 10 side) than the bottom surface 32a of the frame 32 so that a gap is formed between the rotor 30 and the magnet 11 (see FIG. 2), the rotor 30 is Rotates smoothly without hitting the magnet 11. Further, a spacer 41 is provided between the bearing 34 and the boss portion 13 in order to facilitate the rotation of the rotor 30. Further, when the rotor 30 is accommodated in the case C, the flange portion 42 is fixed to the upper portion of the bearing 34 so that the rotor 30 does not rattle in the axial direction of the support shaft 12.

  Further, as shown in FIGS. 2 and 3, a commutator 31 is provided around the bearing 34 in the frame 32. The commutator 31 is provided on a commutator plate 35 made of an insulating material provided integrally with the frame 32, and as four substantially fan-shaped commutator pieces 31a, 31b, 31c, and 31d arranged in an annular shape. Is formed. Moreover, commutator pieces 31a and 31c facing each other among the commutator pieces 31a to 31d are electrically connected, and commutator pieces 31b and 31d facing each other are electrically connected. Further, the commutator piece 31 a and one end of the coil 33 are connected, and the commutator piece 31 d and the other end of the coil 33 are connected.

  The coil 33 disposed so as to face the magnet 11 is substantially fan-shaped, and is substantially line symmetric with respect to the center line L1 of the coil 33 along the radial direction of the rotor 30. The opening angle α1 of the coil 33 is about 90 degrees, like the opening angle α2 of the commutator pieces 31a to 31d, and the center line L1 substantially coincides with the center line of the commutator piece 31a. Further, since the coil 33 is displaced from the rotation center of the rotor 30, it contributes to the vibration of the case C.

  With the above configuration, when current flows through the coil 33 through the terminals 14b and 14c, the pair of brushes 15a and 15b, and the commutator 31, torque is generated in the coil 33 facing the magnet 11, and the rotor 30 rotates. When the rotor 30 rotates, the direction of the current flowing through the coil 33 is reversed by the commutator 31 in accordance with the change in the magnetic poles of the magnet 11, so that the rotor 30 rotates in one direction.

  The adjacent commutator pieces 31a to 31d are separated by a predetermined width so that the commutator pieces are not short-circuited via the brushes 15a and 15b, and the intermediate pad 31e is provided between the commutator pieces 31a to 31d. Is formed. Therefore, when the brushes 15a and 15b are positioned on the intermediate pad 31e, a so-called dead point is generated, which is a region where no current flows through the coil 33 and no torque is generated.

  Therefore, a magnetic pin 36 for embedding the stationary position of the rotor 30 is embedded in the frame 32 so that the rotor 30 does not stop at a dead point when the rotor 30 stops. The magnetic pin 36 is made of iron or nickel, and is disposed on the recess 32b provided in the frame 32, thereby increasing the degree of exposure. The magnetic pin 36 is positioned at an arrangement angle β of about 112.5 degrees (90 degrees + 22.5 degrees) with respect to the center line L1 of the coil 33, and the longitudinal direction of the magnetic body pin 36 is a tangential direction with respect to the circumferential direction. It arrange | positions at the bottom face 32a of the flame | frame 32 so that it may correspond substantially. Here, the arrangement angle β is an angle between a center line L2 passing through the center between both ends 36a and 36b of the magnetic pin 36 and the center of the bearing 34 and the center line L1 of the coil 33.

  When the rotor 30 is stopped (that is, when no power is supplied), magnetism is induced in the magnetic pin 36 by the magnet 11, and a magnetic attractive force is generated between the magnetic pin 36 and the magnet 11. As a result, the rotor 30 stops so that the magnetic pin 36 is positioned on the boundary between the S pole and the N pole. At this time, since the arrangement angle β is 112.5 degrees, the center line L1 of the coil 33 is deviated from the boundary between the north pole and the south pole of the magnet 11, so that the stationary position of the rotor 30 becomes the startable position. ing. This position is also a position where the brushes 15a and 15b and the coil 33 are reliably energized when the vibration motor 1 is started.

  As described above, by providing the magnetic pin 36 in the frame 32, the start error of the vibration motor 1 can be avoided. As a result, the rotor 30 starts smoothly and vibration is generated. In order to increase the vibration amount of the case C, a weight 37 is embedded in the frame 32 as shown in FIGS.

  The weight 37 is a plate-like body that is curved along the circumferential direction of the frame 32, and is embedded in the frame 32 between the magnetic pin 36 and the coil 33 in the circumferential direction of the frame 32. The weight 37 is made of tungsten, brass, or the like having a large specific gravity so as to be non-magnetic. As a result of the eccentric amount of the rotor 30 being increased by the weight 37, high vibration is obtained when the rotor 30 rotates.

  Furthermore, since the weight 37 is non-magnetic, the rotor 30 is reliably stopped at the startable position by the magnetic pin 36 without being affected by the weight 37. As a result, the vibration motor 1 is designed to increase the vibration amount while maintaining the starting performance.

  Further, since the vibration motor 1 is a one-coil motor in which one coil 33 is provided on a disk-shaped frame 32, a space for arranging the weight 37 in the frame 32 is sufficiently wide. Therefore, it is easy to select the size and shape of the weight 37 that is effective for increasing the amount of eccentricity of the rotor 30, and the vibration motor 1 can be reduced in size and sufficient for the incoming notification of the mobile phone. The amount of vibration can be obtained. Furthermore, since it is a one-coil motor, the manufacturing cost is reduced as compared with the case where a plurality of coils 33 are provided.

  As mentioned above, although preferred embodiment of this invention was described, it cannot be overemphasized that this invention is not limited to the said embodiment. For example, the rotor 50 may have a semicircular shape as shown in FIG. The rotor 50 includes a semicircular disk-shaped frame 51. The frame 51 is provided with a commutator 31, a coil 33, and a magnetic pin 36, and a circle is formed between the coil 33 and the magnetic pin 36. A plate-like nonmagnetic weight 52 is provided. In this case, since the rotor 50 has a semicircular disk shape, the amount of eccentricity of the rotor 50 is increased. In order to increase the eccentric amount of the rotor 50 and realize high vibration, it is preferable to form the frame 32 from a high specific gravity resin. The shape of the rotor 30 can also be a sector shape.

  Furthermore, the magnetic body for restricting the stationary position of the rotor 30 is not limited to a rod shape like the magnetic pin 36, and may be a plate shape, for example. Further, the position of the magnetic pin 36 may be such that the rotor 30 is stationary at a startable position where the torque is surely generated in the coil 33 at the time of starting. Furthermore, although the magnet 11 is formed in an annular shape by integral molding, a plurality of fan-shaped magnets 11 magnetized on the N pole and the S pole may be arranged in an annular shape.

It is an exploded perspective view showing one embodiment of a vibration motor concerning the present invention. It is a longitudinal cross-sectional view of the vibration motor shown by FIG. It is a bottom view of the rotor which makes a part of vibration motor shown by FIG. It is a top view of the rotor which makes a part of vibration motor shown by FIG. It is a bottom view which shows the other example of a rotor.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Vibration motor, 11 ... Magnet, 11a, 11c ... N pole, 11b, 11d ... S pole, 30, 50 ... Rotor, 31 ... Commutator, 31a-31d ... Commutator piece, 32, 51 ... Frame, 33 ... Coil, 35 ... commutator plate, 36 ... magnetic material pin (magnetic material), 37, 52 ... weight, C ... case.

Claims (2)

A flat rotor in which one coil is embedded in a frame is rotatably accommodated on a magnet in a case, and a magnetic body for stopping the rotor at a startable position when the rotor is stationary is the coil. In the vibration motor embedded in the frame on the outside,
The vibration motor according to claim 1, wherein a nonmagnetic weight is provided between the magnetic body and the coil.   The vibration motor according to claim 1, wherein the rotor has a disk shape.

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