JP2006224068A - Vibration motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration motor capable of improving an impact resistance with a simple structure and suitable for miniaturization. <P>SOLUTION: Recently, there happens that an output shaft 3 becomes extremely narrow due to a promotion of miniaturization of a vibration motor 1. If the output shaft 3 becomes narrow, the output shaft 3 is easily distorted by gravity of a weight 6. Especially, if a strong shock of drop or the like is added to the vibration motor 1 during its operation, distortion of the output shaft 3 by the gravity of the weight 6 becomes bigger, the weight 6 clashes to an equipment (circuit board of cellular phone or the like) and the output shaft 3 is plastic deformed by receiving strong impact. If the output shaft 3 is plastic deformed, there is a case that a stable vibration can not be generated. So this invention is provided with an elastic member 6B on the outer surface of the weight body 6A in order to have a high performance of impact resistance and a high degree of freedom in modification of weight shape. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vibration motor, and more particularly, to a small vibration motor that is used as a vibration generation source, for example, used as a calling function in a mobile communication device (such as a mobile phone) or a bodily sensation function in a game device. Is.

  Conventionally, it is disclosed by patent documents 1-3 as a technique of such a field. The weight of the vibration motor described in Patent Document 1 includes a first weight extending portion and a second weight extending portion extending in the axial direction of the output shaft, and the first weight extending portion. Is formed in a semi-cylindrical shape so as to avoid the bearing portion, and the second weight extending portion is formed in a semi-arc shape so as to avoid the motor housing. Such a weight shape can continue to rotate the weight regardless of the direction in which the output shaft bends due to impact. The weight of the vibration motor described in Patent Document 2 has a bending prevention body that protrudes in a direction perpendicular to the axis of the output shaft. This bend prevention body prevents the output shaft from being bent by an impact such as dropping. The weight of the vibration motor described in Patent Document 3 is also provided with a bending prevention protrusion that protrudes along the axis of the output shaft.

JP 2002-045793 A JP 07-336941 A Japanese Patent Laid-Open No. 08-196054

  However, the weight applied to the above-described conventional vibration motor is a product in which the shape of the weight itself has been devised according to the situation in which the motor is used. And the weight itself is enlarged, which makes it difficult to apply to models (such as mobile phones) that are required to be downsized.

  An object of the present invention is to provide a vibration motor that can improve impact resistance with a simple configuration and is suitable for downsizing.

  The vibration motor according to the present invention is a vibration motor in which a weight is eccentrically fixed to an output shaft protruding from the front end of the motor body, and the weight is provided with an elastic member on the outer surface of the weight body made of metal. Features.

  In recent years, vibration motors have been required to be further downsized, and there has been a situation where the output shaft becomes extremely thin due to the promotion of downsizing of vibration motors. When the output shaft becomes thin, the output shaft is easily bent due to the weight of the weight. In particular, if a strong impact such as a drop is applied to the vibration motor while the vibration motor is being driven, the weight of the weight increases the deflection of the output shaft, causing the weight to collide with equipment (such as a mobile phone circuit board). The output shaft undergoes plastic deformation under strong impact. If the output shaft is plastically deformed, stable vibration may not be generated. Therefore, in order to achieve a motor having high impact resistance while increasing the degree of freedom in changing the weight shape, an elastic member is provided on the outer surface of the weight body in the present invention. Such a configuration is extremely simple, but is extremely novel with respect to the combination of the weight body and the elastic member in the weight.

  Further, the weight body has a substantially semicircular or substantially fan-shaped cross section, and the outer surface of the weight body is provided with an elastic member on at least one of the front surface, the back surface, and the circumferential surface of the substantially semicircle or the substantially fan shape. Is preferred. The surface on which the elastic member is provided is appropriately selected according to the model to which the vibration motor is applied, but the elastic member can be easily fixed by using the outer surface of the weight main body. Become.

  The weight main body has a substantially semicircular or substantially fan-shaped cross section, and the outer surface of the weight main body is provided with an elastic member at a front corner portion formed by a substantially semicircular or fan-shaped front surface and a circumferential surface. It is preferable that Since the front corner portion of the weight is a place where the weight easily collides with a circuit board in a device (such as a mobile phone), the maximum effect can be achieved with less elastic material with respect to impact resistance.

  Further, it is preferable that the motor body is accommodated in an elastic holder. When the motor body is vibrated by the weight, if the motor body is housed in the elastic holder in order to prevent unnecessary vibration noise from being generated from the housing of the device (for example, mobile phone), the motor body is moved vertically and horizontally by strong impact. As a result, the weight easily collides with a device (such as a mobile phone substrate). Therefore, the above-described configuration in which the elastic member is provided on the outer surface of the weight main body is particularly effective when the motor main body is accommodated in the elastic holder.

  According to the present invention, the shock resistance can be enhanced with a simple configuration, and a vibration motor suitable for downsizing can be realized.

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

  As shown in FIG. 1, the vibration motor 1 includes a cored motor, and includes a motor main body A having a cylindrical metal motor case 2 having a diameter of about 4 mm and a length of about 10 mm. . A stator made of a permanent magnet having N and S poles is fixed to the inner wall surface of the motor case 2, and a rotor having a coil wound around an iron core is accommodated in the motor case 2. An output shaft (shaft) 3 supported by a bearing is fixed at the center of the rotor, and a front end portion of the output shaft 3 extends so as to penetrate the front end portion of the motor case 2. In the motor body A, a resin bracket 4 is fixed to the rear end of the motor case 2 by bending a claw.

  Further, in the motor case 2, a commutator is fixed to the rear end of the output shaft 3, and a pair of brushes are in sliding contact with the commutator. A plate-like energizing terminal is fixed to each brush, and the rear end of each energizing terminal protrudes from a bracket 4 provided at the rear end of the motor case 2. A weight 6 having a substantially sectoral cross section is caulked or press-fitted to the tip portion of the output shaft 3, and the weight 6 is eccentrically fixed to the output shaft 3. The weight 6 may have a substantially semi-cylindrical cross section. Therefore, the motor case 2 itself can be vibrated by swinging the weight 6 with the rotational force of the output shaft 3. Such a vibration motor 1 with a weight is used as a function of calling a user to receive an incoming call by vibrating the casing with a portable small-sized wireless caller or a mobile phone.

  Here, the motor body A is provided with a pair of leaf spring terminals 8 on the left and right sides for making one-touch electrical connection between the energization terminal and the predetermined electrical contact 7a of the circuit board 7. Each terminal 8 is provided corresponding to each energization terminal, and applies a predetermined voltage from the outside to the brush. The base end of each terminal 8 is fixed to each energizing terminal via solder, and a part of the terminal 8 is exposed from the motor body A to the outside.

  The terminal 8 is formed by bending a thin spring plate cut into a predetermined shape. The terminal 8 is formed in a substantially U shape along the axis L of the output shaft 3 in a cantilevered state while extending from the base end portion 8a fixed to the bracket 4 and in a cantilevered state. 3 has an elastic portion 8b having an elastic force in a direction substantially orthogonal to the third. The base end portion 8a is fixed to a current-carrying terminal provided on the bracket 4 via solder, and a part of the elastic portion 8b makes electrical connection with a predetermined electrical contact 7a of the circuit board 7 possible. Exposed from the lower surface of the motor body A.

  Furthermore, the motor body A is covered with a rubber holder 16 having elasticity. As a result, when the motor 1 vibrates with the weight 6, unnecessary vibration noise is prevented from being generated from the housing of the device (for example, a mobile phone).

  Such a vibration motor 1 is arranged on the circuit board 7, and in that state, the motor 1 is pressed in the direction of the arrow Z by a lid of a device (not shown) (for example, a mobile phone), so that the electric contact 7a is connected. The need for soldering can be eliminated. In this case, as indicated by a two-dot chain line, the terminal 8 and the electrical contact 7a of the circuit board 7 are reliably electrically connected in a state where the terminal 8 is elastically deformed and has a predetermined urging force.

  Such a vibration motor 1 is used in a small device such as a mobile phone and further reduction in size is required. However, the output shaft 3 becomes extremely thin as the vibration motor 1 is reduced in size. A situation has occurred. When the output shaft 3 becomes thin, the output shaft 3 is easily bent due to the weight of the weight 6. In particular, when a strong impact such as a drop is applied to the vibration motor while the vibration motor 1 is being driven, the weight of the weight 6 increases the deflection of the output shaft 3 having a diameter of about 1 mm, and the weight 6 becomes a device (cell phone circuit). The output shaft 3 receives a strong impact and plastically deforms. If the output shaft 3 is plastically deformed, stable vibration may not be generated.

  Therefore, in order to achieve a motor having high impact resistance while increasing the degree of freedom in changing the weight shape, the weight body 6A made of metal (for example, tungsten) has a sectional fan shape as shown in FIGS. An elastic member 6B made of silicon rubber is fixed to the entire circumferential surface 6a of the weight main body 6A by an adhesive or fusion. By providing the elastic member 6B at such a position, as shown in FIG. 3, a strong impact such as dropping is applied to the vibration motor 1 while the vibration motor 1 is being driven, and the weight of the weight 6 causes the output shaft 3 to move. Even if the deflection becomes large and the weight 6 collides with a device (such as a circuit board 7 of a mobile phone), the elastic member 6B absorbs a strong impact, thereby avoiding a situation where the output shaft 3 is plastically deformed. Can do.

  In particular, when the motor main body A is accommodated in the elastic holder 16, the motor main body A is likely to swing up and down and left and right due to a strong impact, which makes it easier for the weight 6 to collide with a device (such as a cellular phone substrate). . Therefore, the above-described configuration in which the elastic member 6B is provided on the circumferential surface (outer surface) 6a of the weight main body 6A is particularly effective when the motor main body A is accommodated in the elastic holder 16.

  Needless to say, the present invention is not limited to the above-described embodiment, and modifications of the weight are described below.

  As shown in FIGS. 4 and 5, in the vibration motor 11, the weight 10 includes a weight main body 10A made of a metal having a sectional fan shape (for example, tungsten) and an elastic made of silicon rubber fixed to the fan-shaped front face 10a of the weight main body 10A. Member 10B. Such a weight 10 is effective when the front surface 10a of the weight main body 10A is close to the wall surface C of the cabinet when the motor 1 is loaded in the housing space of the cabinet in a device (such as a mobile phone).

  As shown in FIGS. 6 and 7, in the vibration motor 21, the weight 20 includes a weight main body 20A made of a fan-shaped metal (for example, tungsten) and an elastic made of silicon rubber fixed to the fan-shaped back surface 20a of the weight main body 20A. Member 20B. Such a weight 20 is effective when the back surface 20a of the weight main body 20A is close to the wall surface D of the cabinet when the motor 1 is loaded into the housing space of the cabinet in a device (such as a mobile phone).

  As shown in FIGS. 8 and 9, in the vibration motor 31, the weight 30 includes a weight body 30A made of a metal having a sectional fan shape (for example, tungsten), a fan-shaped front surface 30a, a back surface 30b, and a circumferential surface 30c of the weight body 30A. And an elastic member 30B made of silicone rubber. This is suitable when a general purpose weight is intended.

  As shown in FIGS. 10 and 11, in the vibration motor 41, the weight 40 is formed by a weight body 40A made of a metal having a sectional fan shape (for example, tungsten), a front surface 40a and a circumferential surface 40b of the weight body 40A. And an elastic member 40B made of silicon rubber fixed to the front corner portion R. Since the front corner portion R of the weight 40 is a place where the weight 40 easily collides with the circuit board 7 in the device (such as a mobile phone), the maximum effect can be achieved with a small elastic material with respect to impact resistance. The front corner portion R is formed as a groove portion 40c having an L-shaped cross section in consideration of accommodation of the elastic member 40B.

1 is a cross-sectional view showing a first embodiment of a vibration motor according to the present invention. It is a perspective view of the weight applied to the motor of FIG. It is sectional drawing which shows the state in which the external force was added to the vibration motor. It is sectional drawing which shows 2nd Embodiment of the vibration motor which concerns on this invention. It is a perspective view of the weight applied to the motor of FIG. It is sectional drawing which shows 3rd Embodiment of the vibration motor which concerns on this invention. It is a perspective view of the weight applied to the motor of FIG. It is sectional drawing which shows 4th Embodiment of the vibration motor which concerns on this invention. It is a perspective view of the weight applied to the motor of FIG. It is sectional drawing which shows 4th Embodiment of the vibration motor which concerns on this invention. It is a perspective view of the weight applied to the motor of FIG.

Explanation of symbols

1, 11, 21, 31, 41 ... vibration motor, 3 ... output shaft, 6, 10, 20, 30, 40 ... weight, 6A, 10A, 20A, 30A, 40A ... weight body, 6B, 10B, 20B, 30B , 40B ... elastic member, 6a, 30c, 40b ... circumferential surface, 10a, 30a, 40a ... front surface, 20a, 30b ... back surface, 16 ... holder, A ... motor body, R ... front corner part.

Claims (4)

In the vibration motor in which the weight is eccentrically fixed to the output shaft protruding from the front end of the motor body,
The vibration motor according to claim 1, wherein an elastic member is provided on an outer surface of a weight main body made of metal.   The weight main body has a substantially semicircular or substantially fan-shaped cross section, and the outer surface of the weight main body is provided with the elastic member on at least one of a front surface, a back surface, and a circumferential surface of a substantially semicircular or substantially fan shape. The vibration motor according to claim 1.   The weight main body has a substantially semicircular or substantially fan-shaped cross section, and the outer surface of the weight main body is provided with the elastic member at a front corner portion formed by a substantially semicircular or fan-shaped front surface and a circumferential surface. The vibration motor according to claim 1, wherein the vibration motor is provided. The vibration motor according to claim 1, wherein the motor body is accommodated in a holder having elasticity.

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