JP2003175364A - Electromagnetic actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic actuator capable of emitting a sound without generating strain even during low frequency vibration. <P>SOLUTION: The electromagnetic actuator is equipped with a magnet 7, a pole piece 9 mounted on the magnet 7, a yoke 31 opposed to the pole piece 9, a vibration unit 10 provided with a vibration coil 3 and supported by a spring 17, a case 13 housing them and a diaphragm 23 provided with a voice coil 5. The vibration coil 3 and the voice coil 5 are arranged in the gap part between the pole piece 9 and the yoke 31 in a concentric circular state by inserting the arm part 10a of the vibration unit 10 into the notch 31a formed to the yoke 31. The vibration unit 10 is vibrated by applying a low frequency current to the vibration coil 3 and the diaphragm 23 is vibrated by applying a high frequency current to the voice coil 5. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic actuator used for a mobile phone, a pager (registered trademark) or the like, for notifying a call when a signal arrives by vibrating or sounding.

[0002]

2. Description of the Related Art As this type of electromagnetic actuator, the one disclosed in WO99 / 39843 is known. This electromagnetic actuator is shown in FIG. As shown in FIG. 7, in the electromagnetic actuator 100, the magnet 105 is arranged in the groove portion of the yoke 103 in the case 101, and the coil 109 is located in the groove portion through the gap with the magnet 105 and attached to the diaphragm 107. Is provided, and the yoke 103 is
Upper and lower diaphragms 11 arranged in parallel to the side surface of the casing 101.
It is supported by 1, 113. By applying a low frequency current to the coil 109, the vibration plates 111, 113
Of the diaphragm 107 by vibrating the yoke 103 and applying a high frequency current to the coil 109.
To generate high frequency sound. Also, the case 10
The flange 115 is arranged from 1 toward the inner radial direction to regulate the vibration direction of the yoke 103 in the vertical direction.

[0003]

However, in the above technique, when a high frequency current is applied to the coil 109 while the yoke 103 is vibrating, the high frequency sound is distorted due to the low frequency vibration. is there.

It is therefore an object of the present invention to provide an electromagnetic actuator capable of producing high frequency sound without distortion even in low frequency vibration.

[0005]

According to a first aspect of the present invention, a magnet, a pole piece attached to the magnet, a yoke facing the pole piece, and a vibration coil are attached and supported by an elastic body. It is equipped with a vibration unit, a case that houses them, and a diaphragm equipped with a voice coil. By inserting a notch formed in the yoke of the vibration unit into the arm, the pole piece and the yoke are concentrically formed in the gap portion facing each other. A vibrating coil and a voice coil are arranged, and the vibrating unit vibrates when a low-frequency current is applied to the vibrating coil, and the diaphragm vibrates when a high-frequency current is applied to the voice coil.

According to the first aspect of the present invention, since the voice coil is located in the gap portion sandwiched between the fixed pole piece and the yoke, the vibration unit is not affected by the vibration even when the vibration unit vibrates. In addition to being able to pronounce, the gap portion is formed only at one place, so that leakage of magnetic flux can be reduced.

The invention according to claim 2 is a magnet,
Two pole pieces attached above and below the magnet and two
It is equipped with a yoke facing each pole piece, a vibration unit to which a vibration coil is attached and supported by an elastic body, a case to store these, and a diaphragm to which a voice coil is attached. By inserting the notch formed in the yoke, the vibration coil is arranged in the lower gap part where the pole piece and the yoke face each other, the voice coil is arranged in the upper gap part, and the low frequency current is applied to the vibration coil. The vibrating unit vibrates, and the diaphragm vibrates when a high-frequency current is applied to the voice coil.

According to the second aspect of the present invention, since the voice coil is located in the upper gap portion sandwiched between the fixed pole piece and the yoke, the vibration unit is affected by the vibration even when the vibration unit vibrates. In addition to being able to produce sound without any noise, the vibration coil is arranged in the lower gap portion, so that electromagnetic interference between both coils can be reduced.

The invention described in claim 3 is the invention according to claim 1 or 2.
In the invention described in any one of above, the vibration unit is a molded product obtained by sintering powder of a high specific gravity material.

In the invention described in claim 3, claim 1
In addition to exhibiting the same effect as the invention described in any one of 1 to 2, by making the vibration unit a molded product obtained by sintering powder of a high specific gravity material, a small size and a large mass can be obtained, and the vibration amount can be reduced. Can be increased.

The invention according to claim 4 is the invention according to claims 1 to 3.
The invention described in any one of (1) to (4) above is characterized in that a bridge is interposed between the voice coil and the diaphragm.

In the invention described in claim 4, claim 1
In addition to the same effect as the invention described in any one of 1 to 3, since the diameter of the bridge can be increased on the diaphragm side, the diameter of the driving point with respect to the diaphragm can be increased.

The invention according to a fifth aspect is the first to the fourth aspects.
In the invention described in any one of above, the elastic body is a spring that is fixed to the bottom surface or the top surface of the vibration unit to support the vibration unit.

According to the invention of claim 5, claim 1
It is possible to obtain the same effects as those of the invention described in any one of items 1 to 4 and to simplify the structure of the elastic body.

The invention according to claim 6 is the same as claims 1 to 4.
In any one of the inventions described above, the elastic body is a spring that is fixed to the upper and lower surfaces of the vibration unit and supports the vibration unit at the midpoint of the stretched state.

In the invention described in claim 6, claim 1
The same effect as that of the invention described in any one of 4 to 4 can be obtained, and since the shape of the vibration unit can be increased, the vibration amount can be increased.

The invention according to claim 7 is the invention according to claims 1 to 6.
In any one of the above-mentioned inventions, the yoke is characterized in that a ring-shaped gap of a magnetic material is attached to an upper end surface thereof.

According to the invention of claim 7, claim 1
It is possible to obtain the same operational effect as the invention described in any one of to 6 and to prevent the leakage of the magnetic flux caused by the notch.

[0019]

DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. 1 is a sectional view showing an electromagnetic actuator according to the present invention, and FIG. 2 is an exploded perspective view of the electromagnetic actuator of FIG. The electromagnetic actuator 1 shown in FIG. 1 notifies a user of information received through a mobile phone by vibrating or sounding.

The electromagnetic actuator 1 includes a magnet 7
, A pole piece 9, a vibration unit 10 made of a high specific gravity material on which a vibration coil 3 is mounted, a yoke 31 made of a magnetic material, a case 13 for accommodating them, and a side surface portion 13 of the case 13.
e interposed between the e and the bottom surface of the vibration unit 10, a diaphragm 23 that is a diaphragm whose periphery is fixed on the side surface portion 13e of the case 13, and a diaphragm 23.
Voice coil 5 fixed on top of which high frequency current is applied
And a central portion 13a of the case 13 protruding through the central portions of the magnet 7 and the pole piece 9, and the vibration coil 3 and the voice coil 5 are provided in the gap portion between the pole piece 9 and the yoke 31. By arranging and applying a low frequency current to the vibration coil 3, the vibration unit 10 vibrates in the vertical direction in FIG.
By applying a high frequency current to the diaphragm 23
Vibrates and sounds. In the present specification, the terms “upper” and “lower” are used for convenience, but they do not specify the vertical direction.

The case 13 has a yoke 31 on the bottom surface 13d.
It is fixed (bonded) to the central portion 13 at the central position of the bottom surface 13d.
a plurality of holes 13 that are fixed to a and allow the fluctuating internal pressure to escape
b on the bottom. The side surface portion 13e is fixed to the bottom surface at the lower portion, the diaphragm 23 is fixed to the upper portion, supports the spring 17 at the intermediate portion, and at the same time, is provided with a current supply terminal 13c for the vibration coil 3 and the voice coil 5. The central portion 13a plays a role of positioning the magnet 7 and the pole piece 9.

The magnetic yoke 31 constitutes a gap portion facing the pole piece 9 and forms a magnetic path to the bottom surface of the magnet 7. The vibration unit 10 has three arm portions 10a extending in the center direction in the circumferential direction.
The vibration coil 3 is fixed to the ring portion at the tip by passing through three notches 31a of the yoke 31. One end of the spring 17 is fixed to the bottom surface of the vibrating unit 10 to support the vibrating unit 10, and the other end thereof is the side surface portion 1 of the case 13.
It is fixed to 3e. When electromagnetic force acts on the vibration coil 3, the vibration unit 10 vibrates in the vertical direction.
The notch 31a has a space for the vibration amplitude in the vertical direction.

The resonance frequency of the vibration system consisting of the spring coefficient of the spring 17 and the mass of the vibration unit 10 is made to match the frequency of the low frequency current applied to the vibration coil 3. In the present embodiment, the vibration unit 10 is formed by sintering powder of high specific gravity material such as tungsten. Since tungsten is a high specific gravity material having a specific gravity of about 18, it is possible to increase the amount of vibration even if it is small and has a large mass.

The diaphragm 23 is formed by molding a thin film of a high molecular compound such as polyethylene into a disc shape, and is fixed to the upper surface of the side surface portion 13e by adhesion. Further, in order to obtain a flat vibration characteristic in a wide frequency band, a plurality of cone-shaped moldings are performed.

The voice coil 5 is arranged concentrically with the vibrating coil 3 in a gap portion sandwiched by the pole piece 9 and the yoke 31, and is bonded to the lower surface of the diaphragm 23 via the bobbin 5a. When a high frequency current is applied to the voice coil 5, an electromagnetic force acts on the voice coil 5 by the action of the magnetic field in the gap. The bobbin 5a is arranged to position the voice coil 5 at the center of the gap from the diaphragm which is separated upward. In the compact electromagnetic actuator 1, the intrinsic basic (minimum) frequency of the diaphragm 23 is a high frequency around 1 kHz, so the current applied to the voice coil 5 is called a high frequency current.

The lead wire of the voice coil 5 is a bobbin 5a.
Is connected to the current supply terminal 13c via the upper end surface of the side surface portion 13e. The lead wire of the vibration coil 3 is led out in the outer peripheral direction via the arm portion 10a and the spring 17, penetrates the end face with the side surface portion 13e, and is connected to the current supply terminal 13c.

The upper side (for example, N pole) of the magnet 7 is
It is bonded to the pole piece 9, and the lower side (for example, the S pole) is bonded to the bottom surface of the yoke 31. Since the voice coil 5 and the vibration coil 3 are concentrically arranged side by side in the gap portion, a high-frequency current is supplied to the voice coil 5 from the inside of the mobile phone to generate a sound, and the vibration coil 3 has a low frequency. It is vibrating by supplying electric current.

When both the high frequency current and the low frequency current are simultaneously applied from the inside of the mobile phone, the voice coil 5 is located in the gap portion sandwiched between the fixed pole piece 9 and the fixed yoke 31. , Can be produced independently of low frequency vibration.

Next, the operation of this embodiment will be described based on the above-mentioned configuration. In order to assemble the electromagnetic actuator 1, first the spring 1 is attached to the vibration unit 10.
7, the arm portion 10a and the vibration coil 3 are bonded and fixed, and the pole piece 9 is bonded to the upper surface of the magnet 7. Next, the yoke 31, the central portion 13a, the bottom surface and the side surface portion 13e of the magnet 7 are fixed to the bottom surface 13d of the case 13.

Then, the vibration unit 10 is attached to the arm 1
The spring 17 is adhesively fixed to the side surface portion 13e while inserting the hole 0a into the notch 31a. Subsequently, the diaphragm 23 to which the voice coil 5 and the bobbin 5a are previously attached is adhered to the upper surface circumferential portion of the side surface portion 13e, and finally the lead wires of the voice coil 5 and the vibration coil 3 are connected to the current supply terminal 13c.
Connect to.

In this electromagnetic actuator 1, when a low frequency current (a single frequency of, for example, 150 to 170 Hz as a sensory frequency) is applied to the vibration coil 3 from a circuit in the mobile phone, the low frequency current is applied. The vibration unit 10 vibrates in the vertical direction in the figure by the action of the magnetic field.
When the vibration unit 10 vibrates, the mobile phone holding the case 13 vibrates and transmits information such as an incoming signal to the wearer.

When a high frequency current (a wide band frequency of 900 to 8000 Hz as an audible frequency) is applied to the voice coil 5, the diaphragm 23 vibrates in the high frequency band by the action of the high frequency current and the magnetic field. .
Since the diaphragm 23 is a diaphragm formed by forming a thin film material such as polyethylene into a cone shape, it is possible to reduce the driving force of the high frequency band through the voice coil 5 and the bobbin 5a.
Provides faithful sound emission. When the diaphragm 23 vibrates, a high frequency sound transmits information such as an incoming signal to the wearer through the mobile phone fixing the case 13.

In the present embodiment, the voice coil 5 is located in the gap part sandwiched between the fixed pole piece 9 and the yoke 31, so that the high frequency current and the low frequency current are low even when applied simultaneously. Sound can be generated independently of frequency vibration. Therefore, unlike the case shown in the conventional example of FIG. 7, the inconvenient phenomenon that the high frequency sound is distorted by the low frequency vibration does not occur.

Further, in the present embodiment, the yoke 31 is arranged on the S pole side of the magnet 7 so that only one gap portion is formed, so that the amount of leakage of magnetic flux is reduced and even the bottom surface of the case 13 is reached. The axial length of the magnet 7 can be increased.

Next, other embodiments will be described. In the description, the same parts as those described above are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 3 is a sectional view showing an electromagnetic actuator according to the second embodiment. In the second embodiment,
As shown in FIG. 3, pole pieces 9-1 and 9-2 are fixed to the upper and lower sides of the magnet 7 to form two gap portions opposed to the yoke 31, and the voice coil 5 is placed in the upper gap portion and the lower side is formed. The vibration coil 3 is arranged in the gap portion. A support 13f is fixed to the bottom surface of the case 13, and the pole pieces 9-2, 9-1 and the magnet 7 are arranged on the support 13f.

The spring 17 is interposed between the bottom surface of the vibration unit 10 and the side surface portion 13e of the case 13 as in FIG. 1, and the vibration unit 10 has the arm portion 1 extending in the center direction.
The vibration coil 3 is fixed (adhered) on the surface 0a, and the arm portion 10a penetrates the notch 31a. Vibration unit 10
Since it vibrates up and down from the position shown in FIG. 3, a support base 13f is provided to arrange the lower gap portion upward. The voice coil 5 is directly fixed to the diaphragm 23, the arm portion 10a is miniaturized, the radial gap of the gap portion is narrowed, and the diameter of the magnet 7 is increased accordingly.

When a high-frequency current is supplied to the voice coil 5 from inside the mobile phone, the diaphragm 23 vibrates and sounds, and when a low-frequency current is supplied to the vibration coil 3, the vibration unit 10 vibrates, and information such as an incoming call is received. To inform the wearer.

Therefore, also in the second embodiment, the voice coil 5 is located in the gap portion sandwiched between the fixed pole piece 9-1 and the yoke 31 made of a magnetic material, so that the high frequency current and the low frequency current are generated. Even when the currents are simultaneously applied, the inconvenient phenomenon that the high frequency sound is distorted does not occur.

In the present embodiment, the diameter of the magnet 7 can be increased and the voice coil 5 and the vibration coil 3 are vertically separated from each other, so that electromagnetic interference between the coils can be reduced. You can

The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention. For example, in the embodiment shown in FIGS. 1 and 2, the diameter of the vibration coil 3 is equal to that of the voice coil 5.
The diameter of the vibration coil 3 is smaller than that of the vibration coil 3 and the vibration coil 3 is arranged inside the gap portion.
Is arranged outside the gap portion, the length of the arm portion 10a can be further reduced. In this case, since the diameter of the voice coil 5 becomes smaller, if a ring-shaped bridge 41 having a larger diameter on the diaphragm side is interposed between the voice coil 5 and the diaphragm 23 as shown in FIG.
The diameter of the drive point for the diaphragm 23 can be increased.

Further, in the embodiment shown in FIGS. 1, 2 and 3, the spring 17 is fixed to the bottom surface of the vibration unit 10 to support the vibration unit 10, but as shown in FIGS. The structure may be fixed to the upper surface of the vibration unit 10 to support the vibration unit 10.

Further, in the embodiment shown in FIGS. 1 to 5,
Although the spring 17 has a spring structure in which a flat state in a stationary state is curved upward and downward, as shown in FIG. 6, two springs 17-1 and 17-2 are fixed to the upper and lower surfaces of the vibration unit 10, and both springs are fixed. Extend the spring to extend the side surface 13e of the case 13
The vibration unit 10 to the springs 17-1, 1
You may arrange | position at the midpoint of 7-2. In this case, it is not necessary to escape the contact with the curved spring, and the shape of the vibration unit 10 can be enlarged so as to occupy the entire space.

Furthermore, in the embodiment shown in FIGS. 1 to 5, since the yoke 31 has the notch 31a, magnetic flux leaks. However, in the embodiment shown in FIG. 6, a ring is formed on the upper end surface of the yoke 31. Since the cap 42 made of a magnetic material is attached, the leakage of magnetic flux can be prevented.
In addition, the bobbin 5 is provided between the voice coil 5 and the diaphragm 23.
The vibration bobbin 3a is also interposed between the vibration coil and the arm portion 10a by interposing a, and the magnetic flux and the coils 3 and 5 are arranged at the center position of the gap portion.

[0045]

According to the first aspect of the present invention, the distortion of the high frequency sound due to the influence of the vibration does not occur, and the leakage of the magnetic flux can be reduced.

According to the second aspect of the present invention, the distortion of the high frequency sound due to the influence of vibration does not occur, and at the same time, the electromagnetic interference between the coils can be reduced.

According to the invention described in claim 3, the same effect as the invention described in any one of claims 1 and 2 can be obtained, and the vibration force can be further increased.

According to the invention described in claim 4, the same effect as the invention described in any one of claims 1 to 3 can be obtained, and the diameter of the driving point with respect to the diaphragm can be increased.

According to the invention described in claim 5, the same effect as that of the invention described in any one of claims 1 to 4 can be obtained, and the structure of the elastic body can be simplified.

In the invention described in claim 6, the same effect as the invention described in any one of claims 1 to 4 can be obtained, and the vibration amount can be increased.

In the invention described in claim 7, the same effect as that of the invention described in any one of claims 1 to 6 can be obtained, and the leakage of the magnetic flux caused by the notch can be prevented.

[Brief description of drawings]

FIG. 1 is a sectional view showing an electromagnetic actuator according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of the electromagnetic actuator of FIG.

FIG. 3 is a sectional view showing an electromagnetic actuator according to a second embodiment of the present invention.

FIG. 4 is a cross-sectional view showing an electromagnetic actuator according to a mode in which a vibration coil is arranged outside a gap portion.

FIG. 5 is a cross-sectional view showing an electromagnetic actuator according to a mode in which a bridge is interposed between a voice coil and a diaphragm.

FIG. 6 is a cross-sectional view showing an electromagnetic actuator according to a mode in which stretched springs are fixed to upper and lower surfaces of a vibration unit.

FIG. 7 is a sectional view showing a conventional electromagnetic actuator.

[Explanation of symbols]

1 Electromagnetic actuator 3 Vibration coil 5 voice coils 7 magnet 9 pole pieces 10 Vibration unit 13 cases 17 Spring (elastic body) 23 diaphragm 31 York 41 bridge 42 cap

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Makoto Fujii             No. 3854 Shimotsuruma, Yamato City, Kanagawa Prefecture, Techno             Plaza Yamato Shico Giken Co., Ltd. (72) Inventor Katsushi Okubo             No. 3854 Shimotsuruma, Yamato City, Kanagawa Prefecture, Techno             Plaza Yamato Shico Giken Co., Ltd. F term (reference) 5D107 AA05 BB08 CC09 CC11 FF09

Claims (7)

[Claims] 1. A magnet, a pole piece attached to the magnet, a yoke facing the pole piece, a vibration unit having a vibration coil attached thereto and supported by an elastic body, a case for housing these, and a voice coil. The vibration coil and the voice coil are concentrically arranged in the gap where the pole piece and the yoke face each other by inserting the notch formed in the yoke into the arm of the vibration unit. An electromagnetic actuator characterized in that a vibration unit vibrates when a low-frequency current is applied to the diaphragm, and a diaphragm vibrates when a high-frequency current is applied to a voice coil. 2. A magnet, two pole pieces mounted above and below the magnet, a yoke facing the two pole pieces, a vibration unit mounted with a vibration coil and supported by an elastic body, and these. The vibration coil is placed in the lower gap part where the pole piece and the yoke face each other by inserting the notch formed in the yoke of the arm of the vibration unit. Then, a voice coil is arranged in the upper gap part, and a vibration unit is vibrated by applying a low frequency current to the vibration coil, and a diaphragm is vibrated by applying a high frequency current to the voice coil. . 3. The electromagnetic actuator according to claim 1, wherein the vibration unit is a molded product obtained by sintering powder of a high specific gravity material. 4. The electromagnetic actuator according to claim 1, wherein a bridge is interposed between the voice coil and the diaphragm. 5. The electromagnetic actuator according to claim 1, wherein the elastic body is a spring fixed to the bottom surface or the top surface of the vibration unit to support the vibration unit. 6. The elastic body is a spring fixed to the upper and lower surfaces of the vibrating unit and supporting the vibrating unit at the midpoint of the stretched state.
The electromagnetic actuator according to any one of 1. 7. The electromagnetic actuator according to claim 1, wherein the yoke has a ring-shaped gap of a magnetic material mounted on its upper end surface.