JP2000334379A - Vibration actuator for generating sound and low frequency vibration - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the propagation of large vibration to the outside by elastically supporting not only a vibrator on a magnetic circuit by a damper but also the magnetic circuit on a cover by a flexible structure and transmitting relative vibration to the cover when an AC signal is a low frequency signal. SOLUTION: In a vibration actuator for a pager, a vibrator 9 is bonded to the annular flat part 8 of a collision part and the annular flat part 8 and a damper 6 are integrally fomed. The damper 6 supports the vibrator 1 and the center position of a coil 5 and is supported by a damper support part 7 so as to be displaceable in an up and down direction. A magnetic circuit is constituted by bonding a plate 2 comprising a magnetic material to one magnetic pole of a magnet 1 and bonding a yoke 3 comprising a magnetic material to the other magnetic pole thereof. Since the annular flat part 8 is largely displaced by the coil 5 when the vibrator is driven at relatively low frequency, the vibrator collides with a collision cover 12 through an elastic material 10 and the vibration generated by this collision is propagated to the outside.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electroacoustic transducer, which is installed in a portable telephone or the like and emits a sound for calling when a signal is received, capable of outputting low-frequency vibration.
This is an electric vibration transducer used for notifying a call by vibration, and can be used particularly for the purpose of reducing the size and weight.

[0002]

2. Description of the Related Art A conventional pager vibration actuator is also called a pager vibration motor or a vibration generation actuator, and needs to be small, thin, capable of generating vibration with low power consumption, and inexpensive. However, since the purpose is to generate only vibration, it is naturally impossible to make a voice call or generate a conversation sound. Therefore, at least two or more device parts are required for incoming information and voice generation.

[0003] In addition, a vibrating actuator for a pager, which is often used, consumes a large amount of starting power because it rotates a relatively large mass. Further, the number of parts is increased due to the configuration of rotation, and there are problems in reliability and accuracy control. Because it has a brush for current switching because it uses DC current, it may cause malfunctions during rotation,
Also, large electromagnetic noise is generated.

FIG. 8 shows the most commonly used vibration motor for a pager. A counterweight 29 rotates through a shaft 28 driven by a drive motor 27 constituted by a cylindrical coreless rotor, and generates whirling vibration. The drive motor 27 is formed of a curved permanent magnet and a cylindrical coreless rotor,
Further, it is necessary to form a plurality of magnetic poles in order to obtain a rotational driving force, and there is a limit in precision management and manufacturing cost for realizing the driving motor 27 having a small diameter. Furthermore, since the direction of the vibration mode is omnidirectional, there is a limit to the effective use of the drive current applied to the coreless rotor as the propagation of vibration energy to the outside.

[0005]

The conventional vibration actuator for a pager can generate vibration, but cannot generate sound, and the efficiency of conversion to external vibration energy is not always good. In addition, the starting power cannot always be reduced, and it is quite impossible to reduce the external dimensions. There is a limit in reducing the cost, and there is also a case where a rotation operation failure is likely to occur, and a case having a core generates particularly large electromagnetic noise.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electric vibration converter, in particular a vibration actuator for a pager, which can generate vibration and sound and can effectively convert a driving current into vibration energy. An object of the present invention is to provide a vibration actuator for generating sound and low-frequency vibration, which is easily flattened and has few malfunctions.

[0007]

In order to achieve the above object, the present invention provides a magnetic circuit having an annular magnetic gap including a permanent magnet and a yoke, and a coil disposed in the magnetic gap. A vibration actuator having a cover attached with an electric vibration converter that causes an AC electric signal to flow through the coil to cause relative vibration between the vibration body and the magnetic circuit. The magnetic circuit is elastically supported by a damper, and the magnetic circuit is elastically supported by a flexible component on the cover. When the AC signal is a signal having a frequency lower than the audio frequency, the relative vibration is reduced. Is transmitted to the cover, wherein when the AC vibration is a high-frequency sound frequency, the relative vibration causes the vibrating body to vibrate and emit a sound. It is a vibration actuator for dynamic generation.

[0008] The flexible structure may be made of thin rubber fixed to the cover while covering the outer surface of the magnetic circuit.

According to one embodiment, a part of the thin rubber can be used also as the elastic material.

According to another embodiment of the present invention, the flexible structure is a tubular rubber that extends around the outer periphery of a magnetic circuit, and the yoke top of the magnetic circuit is connected to the cover of the cover via the tubular rubber. It is possible to adopt a cell configuration locked to the support portion.

Further, the flexible structure may be constituted by an annular damper having an inner end fixed to the bottom of the magnetic circuit and an outer end fixed to the support of the cover.

The yoke may be composed of a plurality of thin plates. As a result, the annular wall surface of the yoke can be made vertical with high accuracy, so that it is possible to cope with a large relative displacement between the coil and the magnetic circuit.

According to one embodiment of the present invention, the cover is a cover of a portable telephone.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described based on examples with reference to the drawings.

FIG. 1 shows an embodiment of a vibration actuator for a pager according to the present invention, which uses the driving principle of a moving coil type electro-acoustic transducer for generating sound. The vibrating body 9 is bonded to the annular flat portion 8 of the collision portion, and the damper 6 is formed integrally with the annular flat portion 8.

The damper 6 supports the center position of the vibrating body 9 and the coil 5 and has a structure that can be softly displaced in the vertical direction, and is supported by the damper support 7. The damper support 7 has, for example, a cylindrical configuration with a step, and is fixed to the center hole of the plate 2.

In the magnetic circuit, a disk-shaped magnetic plate 2 having a hole at the center is adhered to one magnetic pole of a magnet 1 which is a columnar permanent magnet magnetized in the thickness direction, and the other magnetic pole is formed. Is formed by bonding a molded yoke 3 of a magnetic material. A coil 5 and a bobbin 4 are provided between the yoke 3 and the plate 2.
An annular gap that moves up and down is formed, resulting in a space with a high magnetic flux density.

When driven at a relatively low frequency,
Since the displacement of the annular flat portion 8 due to the coil 5 increases, the generation of unnecessary sound due to the collision is reduced through the elastic member 10 and the flat portion 8 collides with the collision cover 12. The annular flat portion 8 colliding with the collision cover 12 is structurally strong and collides on average. The vibration generated by the collision propagates to the outside. The elastic material 11 on the plate 2 also reduces unnecessary sound at the time of collision.

When the incoming signal is to be notified by vibration, it is driven at a low frequency of several hundred hertz or less to transmit the collision vibration between the annular flat portion 8 and the collision cover 12 to the outside. At this time, the vibration direction is only the vertical direction, and the vibration energy can be efficiently extracted to the outside. In order to increase the amplitude of vibration at a low frequency and not to reduce the driving force, the damper 6 needs to have a flexible configuration having a large vertical compliance.

In order to further increase the vibration generated outside, it is effective to cause the yoke 3 to collide with the collision cover 12. In the embodiment of FIG. 1, the rubber 13 presses the bottom of the yoke 3 of the magnetic circuit with the rubber bottom 15, and the rubber end 14,
At 17, it adheres to the collision cover 12. Magnet 1, plate 2
The magnetic circuit including the yoke 3 is supported by the tension of the rubber 13.

FIG. 2 shows that a current is applied to the coil 5 and the elastic material 1
0 shows a state in which the vehicle has collided with the collision cover 12 via the “0”. Since it is driven at a low frequency, the collision portion of the annular flat portion 8 keeps holding the elastic member 10 for a long time. As a reaction, the magnetic circuit including the yoke 3 moves away from the collision cover 12. When the current flowing through the coil 5 rapidly weakens, goes to zero, or changes polarity, the reaction rapidly weakens, goes to zero, or reverses.

FIG. 3 shows an example of a square wave driving current. When the current level is A, the coil 5 shown in FIG.
While the force in the collision direction to 2 continues and the level A continues, the coil 5 will continue to hold down the elastic material 10 almost after the collision. As a reaction, the magnetic circuit including the yoke 3 moves away from the collision cover 12 against the tension of the rubber 13. Almost at the same time when the current level becomes zero and the coil 5 separates from the elastic member 10, the yoke top 16 collides with the collision cover 12 via the rubber end 14 also serving as the elastic member, and generates vibration to the outside. Another elastic material may be added between the rubber end 14 and the yoke top 16 in order to reduce the impact sound.

As a result of the above, the vibration generated at the time of the collision of the magnetic circuit including the yoke 3 is added to the vibration generated at the time of the collision due to the coil 5, and as shown in FIG. The simple yoke 3 is fixed to the collision cover 12 by the support portion 26, and the level of vibration transmitted to the outside is larger than that of the collision vibration only by the coil 5.

In order to increase the effect of the present invention, the vibrating body 9
As shown in FIG. 4 in a partially cutaway perspective view of the actuator in which the shape of the damper is omitted, the spiral-shaped damper 6 is long and thin so that it can cope with the displacement in the vertical direction greatly and softly. Further, even if the width is narrow, the rigidity in the width direction is increased to 1 mm or more, and the deviation from the center of the annular flat portion 8 and the coil 5 supported by the plurality of dampers 6 is reduced so that the coil 5 and the yoke 18 can be almost freely. It is good to make it displace up and down.

Another embodiment of the present invention is shown in the sectional view of FIG. This also shows a method of effectively extracting energy at the time of collision of the magnetic circuit including the yoke 3 as vibration.
The magnetic circuit is supported on a flat portion on the back surface of the yoke top portion 16 at the outermost periphery by a support portion 21 via a tubular rubber 20. Support part 21
Is fixed to the collision cover 12, the yoke 3 can be displaced up and down relatively flexibly. A foamed resin may be used instead of the tubular rubber.

FIG. 6 shows another embodiment of the present invention.
The magnetic circuit including the yoke 3 is supported by bonding the inner peripheral portion of the annular damper 25 to the bottom of the yoke 3 and bonding the outer peripheral portion to the annular support portion 23. The magnetic circuit including the yoke 3 can be displaced up and down relatively freely. In addition, a lead wire from the coil 5 is taken out from a window 24 provided in the annular support portion 23.

The embodiment shown in FIGS.
In addition to the vibration when the upper annular flat portion 8 collides with the collision cover 12 via the elastic member 22 by the driving force of the above, the magnetic circuit including the yoke 3 is separated from the collision cover 12 by the reaction with the coil 5. Thereafter, the yoke top 16 collides with the collision cover 12 due to the elastic restoring force of the rubber 13, the tubular rubber 20, and the annular damper 25, and vibration is generated.

When the magnetic circuit composed of the magnet 1, the plate 2 and the yoke 3 has an excess of 10 g, the drive frequency is about 80 Hz and the coil 5 of the vibration actuator for a pager of the present invention is used.
And the yoke 3 alternately collide with the collision cover 12, so that the bodily sensation vibration is large, and the level of unnecessary sound when the collision is made with an elastic material interposed therebetween can be made relatively low.

As shown in FIG. 4, the yoke 18 is formed by laminating a plurality of thin magnetic material plates and press-molded, so that the height of the annular vertical wall facing the plate 2 can be easily increased. Become. Further, in this case, if the slits 19 are formed at a plurality of positions, the pressure molding is further facilitated.

[0030]

Since the present invention is configured as described above, it has the following effects.

It is natural that the coil is soft and easy to move in the vertical direction, and it is possible for the magnetic circuit such as the yoke to move in the vertical direction if the displacement is relatively small. Since energy as a reaction from the coil is stored as elastic energy of rubber or the like supporting the magnetic circuit and converted into vibration when released, vibration propagation to the outside can be increased.

Further, both the coil and the yoke move only in the vertical direction, and can collide with a relatively thin and liable resin plate so that vibration energy can be effectively propagated and vibration energy can be effectively taken out. Also, since the starting power is relatively small, power consumption can be reduced.

In the case of the present invention in which the damper is disposed inside, the diameter of the drive coil is large, and the outer diameter can be reduced in spite of the large driving force. The thickness is 6
mm, it is highly likely that the thickness is acceptable when the vibration generation function and the sound generation function are both used.

Further, the assembling work and accuracy control are simplified, and since there is no rotating part as in the prior art, there is no brush or bearing part, and the number of parts as a whole can be reduced. Further, there is no disadvantage that the rotation is not started depending on the position of the electric contact. Of course, no electromagnetic noise is generated because there is no switching of the electrical contacts.

[Brief description of the drawings]

FIG. 1 is a sectional view of a vibration actuator for a pager of the present invention.

FIG. 2 is a sectional view of the embodiment of FIG. 1 at the time of driving.

FIG. 3 is a diagram showing an example of a drive current.

FIG. 4 is a partially cutaway perspective view of an actuator used in the present invention.

FIG. 5 is a sectional view of another embodiment of the present invention.

FIG. 6 is a sectional view of another embodiment of the present invention.

FIG. 7 is a sectional view of an embodiment of the present invention before improvement.

FIG. 8 is a perspective view of a conventional cylindrical vibration motor for a pager.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 magnet 2 plate 3, 18 yoke 4 bobbin 5 coil 6 damper 7 damper support 8 annular flat portion 9 vibrator 10, 11, 22 elastic material 12 collision cover 13 rubber 14, 17 rubber end 15 rubber bottom 16 yoke top Reference Signs List 20 tubular rubber 21, 26 support part 23 annular support part 24 window 25 annular damper

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04M 1/03 H04M 1/03 C H04R 9/02 101 H04R 9/02 101C 102 102E 103 103Z

Claims (7)

[Claims] 1. A magnetic circuit having an annular magnetic gap is constituted by a permanent magnet and a yoke, a coil is arranged in the magnetic gap, a vibrator is attached to the coil, and an AC electric signal flows through the coil. In a vibration actuator in which an electric vibration converter that causes relative vibration between the vibrating body and the magnetic circuit is attached to a cover, the vibrating body is elastically supported by the damper on the magnetic circuit, and The cover is elastically supported by a flexible component, and when the AC signal is a lower frequency signal than the audio frequency, the relative vibration is transmitted to the cover, and the AC vibration is a high frequency audio frequency. The vibrating body vibrates due to the relative vibration to generate a sound, and a sound and a low-frequency vibration generating vibration actuator are provided. 2. The vibration actuator according to claim 1, wherein the flexible structure is made of a thin rubber fixed to the cover while covering an outer surface of the magnetic circuit. 3. The vibration actuator according to claim 2, wherein a part of the thin rubber is also used as the elastic material. 4. The flexible structure is a tubular rubber that extends around an outer periphery of a magnetic circuit, and a top of a yoke of the magnetic circuit is locked to a supporting portion of the cover via the tubular rubber. The vibration actuator for generating sound and low-frequency vibration according to any one of claims 1 to 3, characterized in that: 5. The flexible structure according to claim 1, wherein the flexible structure comprises an annular damper having an inner end fixed to a bottom of the magnetic circuit and an outer end fixed to a support of the cover. And a vibration actuator for generating low-frequency vibration. 6. The vibration actuator for generating sound and low-frequency vibration according to claim 1, wherein said yoke is constituted by a plurality of thin plates. 7. The vibration actuator for generating sound and low-frequency vibration according to claim 1, wherein the cover is a cover of a portable telephone.