JPH1175295A - Electromagnetic receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electromagnetic receiver whose sound pressure characteristic is made stable even when the temperature in an operating environment is changed. SOLUTION: In this electromagnetic receiver, a magnetic diaphragm 2 consisting of a 1st armature disk 22 and a 2nd armature disk 23 whose diameter is smaller than that of the 1st armature disk 22 which are adhered sequentially on a resin made diaphragm 21 is placed inside a resin made package 1 whose front side has sounding holes and whose rear side is open, and a magnetic yoke plate 3 consisting of a magnet 31 and a coil 32 generating vibration to the magnetic diaphragm 2 is placed in the rear side opening of the package 1. In this case, a thermal expansion coefficient of the 1st armature disk 22 is selected smaller than a thermal expansion coefficient of the resin made diaphragm 21, and a thermal expansion coefficient of the 2nd armature disk 23 is selected more than that of the 1st armature disk 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic receiver having stable sound pressure characteristics.

[0002]

2. Description of the Related Art An electromagnetic receiver is used as a voice reproducing component in a telephone handset or the like.

Conventionally, an electromagnetic receiver has a vibration plate that partitions the inside of a container into a front-side sound-emitting cavity and a back-side cavity, and is disposed inside the container. Excitation means for generating vibration corresponding to the audio signal on the diaphragm has been arranged.

[0004] For example, a housing-shaped resin container having an opening on the back side and a sound emission hole on the front surface is used, and a magnetic diaphragm is arranged inside the resin container, and a coil serving as an exciting means of the magnetic diaphragm is provided. The yoke plate on which the magnets are arranged is arranged at the back opening of the container.

[0005] In such a structure, the container constituted by the housing-shaped resin container and the yoke plate also serving as the back cover is divided into two spaces by the magnetic vibrating plate. Then, when an alternating current corresponding to the audio signal of the external drive circuit is supplied to the coil, the combined magnetic flux of the coil and the magnet fluctuates, and the magnetic diaphragm is drawn to the coil and the magnet side, and It returns to its initial state and vibrates in a predetermined manner. Therefore, the air in the surface sound emitting side cavity vibrates and resonates, and a sound corresponding to the sound signal is emitted from the sound emitting hole.

[0006] In the above-mentioned structure, an iron-based magnet is provided so that the composite magnetic flux of the magnet and the coil can be stably applied to the magnetic diaphragm.
At the center of the yoke plate made of a magnetic metal such as nickel alloy or magnetic SUS, a protruding portion protruding into the container is provided, and a coil and a ring-shaped magnet are arranged concentrically around the protruding portion. I was That is, the magnetic flux of the coil and the magnet passes through the magnetic metal yoke plate, is concentrated on the protrusion, and the protrusion is emitted. Therefore, the vibration operation largely depends on the distance between the protrusion and the magnetic body diaphragm. The protruding portion is formed by processing a metal plate (magnetic material) by press working.

Further, in order to improve the vibration characteristics in the high-frequency range, the magnetic diaphragm is constituted by a resin diaphragm made of a resin film and an armature made of a magnetic thin metal plate which receives the magnetic flux of the above-mentioned excitation means. . In particular, the weight is reduced by employing a resin diaphragm, and the magnetic flux is efficiently received by attaching an armature having a smaller diameter than the diameter of the resin diaphragm.

[0008] Such a magnetic diaphragm is formed at the time of assembling the electromagnetic receiver. That is, a resin film-made diaphragm is stuck and fixed in a container, and a central portion of the fixed resin film-made diaphragm, that is, a silicone-based soft adhesive is applied so as to correspond to the protrusion of the yoke plate. It was formed by sticking armature.

This diaphragm made of a resin film is made of, for example, a polyetherimide resin, has a diameter of 18 mm, a thickness of about 25 μm, and a thermal expansion coefficient of, for example, 30 × 10 ⁻⁶ / ° C. Armah is made of an iron-nickel alloy, has a diameter of 13 mm, and has a thickness of about 5 mm.
0 μm, and its thermal expansion coefficient is, for example, 4.2 × 10
⁻⁶ / ° C.

[0010]

In the magnetic diaphragm having the above-described structure, in order to pursue miniaturization and stably reproduce sound in a low-frequency region, the diaphragm is formed as described above.
It is composed of a very thin film of about 5 μm.
An armature was stuck to one main surface of the diaphragm. Therefore, it is difficult to match the thermal expansion coefficients of the resin film diaphragm and the armature, and due to changes in ambient temperature,
There was a problem that the resin film diaphragm was easily warped by the bimetal principle. In the above structure,
In a magnetic diaphragm that did not warp at 25 ° C.,
At 80 ° C., warpage of about 60 μm occurs.

As described above, when the magnetic body diaphragm warps, the distance between the projecting portion of the yoke plate and the armature fluctuates, and the effect of the magnetic flux received from the excitation means fluctuates. As a result, there is a problem that the sound pressure sensitivity fluctuates.

The present invention has been devised in view of the above-mentioned problems, and has as its object the purpose of the present invention even when the use environment temperature changes.
An object of the present invention is to provide an electromagnetic receiver having stable characteristics with little fluctuation in sound pressure sensitivity.

[0013]

SUMMARY OF THE INVENTION According to the present invention, a first disk-shaped armature is provided on a resin diaphragm inside a resin-made casing having a sound emission hole on the front surface and an open back surface. A magnetic diaphragm, which is formed by sequentially attaching a second disk-shaped armature smaller than the diameter of the first disk-shaped armature, is disposed, and excitation is generated in the magnetic-plate vibration at the back opening of the container. In the electromagnetic receiver having a magnetic yoke plate on which magnets and coils are disposed, the first disk-shaped armature has a thermal expansion coefficient smaller than a thermal expansion coefficient of a resin diaphragm and a second circular armature. The plate-shaped armature is an electromagnetic receiver characterized in that its coefficient of thermal expansion is larger than that of the first disk-shaped armature.

[0014]

According to the present invention, the magnetic diaphragm has a first armature, which is smaller than the thermal expansion coefficient of the resin diaphragm on the resin diaphragm, and which is larger than the thermal expansion coefficient of the first armature. The second armatures are respectively adhered and configured.

That is, in terms of the thermal expansion coefficient configuration, the thermal expansion coefficient is arranged in the order of large (resin diaphragm), small (first armature), and large (second armature).
Therefore, due to the difference in thermal expansion coefficient between the resin diaphragm and the first armature, for example, even when a stress occurs that causes the magnetic diaphragm to warp toward the resin diaphragm at the time of temperature rise, the first armature may be used. Due to the difference in the coefficient of thermal expansion between the first armature and the second armature affixed on the first armature, a warping stress is simultaneously generated on the second armature side. Thus, at least the portion to which the second armature is stuck can be restored to the initial planar position at normal temperature.

Therefore, even if the temperature of the use environment changes, it is possible to suppress at least a change in the distance between the first armature and the second armature that is released from the excitation means such as magnets and coils disposed on the yoke plate. In addition, the sound corresponding to the sound signal can be faithfully reproduced without the sound pressure sensitivity largely changing due to the temperature change.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an electromagnetic receiver according to the present invention will be described with reference to the drawings. FIG. 1 is a sectional structural view of the electromagnetic receiver of the present invention.

The electromagnetic receiver according to the present invention has a cylindrical body 10 constituting the container 1 and a lid 11 having a sound emission hole 12 formed therein.
A magnetic vibrating plate 2 having first and second disk-shaped armatures 21 and 22 adhered to a resin vibrating plate 23;
1. A magnetic yoke plate (hereinafter, simply referred to as a yoke plate) on which the coil 32 is disposed.

The container 1 is made of, for example, a heat-resistant resin such as a liquid crystal polymer.
And a lid 11 that closes the surface opening of the cover.
In addition, a yoke plate 3 is arranged at an opening on the back surface of the cylindrical main body 10. As a result, the container of the entire electromagnetic receiver is constituted by the cylindrical main body 10, the lid 11, and the yoke plate 3.

The cylindrical body 10 and the lid 11 may be integrally formed by resin molding, or conversely, the cylindrical body 10 and the magnetic yoke plate 3 may be integrally formed by resin molding. It may be targeted. In the present embodiment, an example will be described in which the three members constituting the container are separate members.

A cover 11 having a sound emission hole 12 for emitting a sound corresponding to an audio signal to the outside is attached to an opening on the front side (sound emission side) of the cylindrical main body 10 through an adhesive. I have.

A step portion 1 for fixing the magnetic diaphragm 2 and the magnetic yoke plate 3 is provided on the inner surface of the cylindrical main body 10.
3 is protrudingly provided. The lower surface of the magnetic diaphragm 2 is joined to the front surface of the step 13, and the lower surface of the magnetic yoke plate 3 is joined to the upper surface of the outer periphery of the step 13.

The yoke plate 3 is made of Ni-plated iron or SU.
S430 or other magnetic metal material, and the cylindrical main body 10
Is bonded to the lower surface of the above-mentioned stepped portion 13 via a thermosetting adhesive so as to seal the opening on the back surface side. At the center of the yoke plate 3, a cylindrical projection 33 projecting toward the inside of the container 1 is formed.

On the outer periphery of the cylindrical projection 33, a coil 32 formed by winding a coil thin wire is arranged. Further, a ring-shaped magnet 31 is provided around the outer peripheral portion on the front side of the yoke plate 3 so as to surround the projecting portion 33. Further, a sound adjustment hole 34 that penetrates the thickness of the yoke plate 3 is formed in a part of the yoke plate 3, and a mesh cloth (acoustic resistance cloth) 35 is attached to an opening of the sound adjustment hole 34.

The yoke plate 3 has a diameter of, for example, 17 mm and a thickness of 0.4 mm, and the cylindrical projection 33 has a diameter of 2 to 5 m.
m and a height of about 0.5 to 1.5 mm. Also,
Both ends of the coil 32 of the coil 32 are connected to lead terminals (not shown) projecting from the container 1.

In the yoke plate 3 having the above structure, the coils 32
And the magnetic flux generated from the ring-shaped magnet 31 are combined and pass through the yoke plate 3 to form the cylindrical projection 33.
Will be concentrated and released.

The magnetic diaphragm is a resin diaphragm 21 made of a heat-resistant resin film such as polyimide or polyetherimide.
And N affixed to the main surface on the front side of the resin diaphragm 21.
i, 42Ni—Fe, a first armature 22 made of a magnetic metal such as an iron-nickel alloy, and a second armature 22 made of a magnetic metal such as a SUS alloy adhered to the main surface of the first armature 22 on the front surface side. Armature 23.

Resin diaphragm 21 and first armature 22
And the first armature 22 and the second armature 23 are bonded via a silicone-based soft adhesive (rubber hardness 30 to 70).

The resin diaphragm 21 is specifically made of polyetherimide and has a diameter of, for example, 18 mm.
(The diameter of the vibrating part is 16 mm) and the thickness is 25 μm.
m, and its coefficient of thermal expansion is 30 × 10 ⁻⁶ /
° C. The first armature 22 is specifically made of an iron-nickel alloy and has a diameter of, for example, 13 mm.
And its thickness is about 50 μm, and its thermal expansion coefficient is 4.2 × 10 ⁻⁶ / ° C. The second armature 23 is specifically made of magnetic SUS and has a diameter of, for example, 6 mm and a thickness of 127 μm.
And its thermal expansion coefficient is 20 × 10 ^-6 / ° C.
It has become.

Further, the outer peripheral portion of the resin diaphragm 21 is subjected to a drawing process having a Ω-shaped cross section.

The magnet 31 is made of, for example, a rubber component and Fe-Al
-It is formed into a ring shape by mixing and solidifying with a magnetic steel component such as -Ni-Co system or Cu-Ni-Fe system. The ring-shaped magnet 31 is bonded to the upper surface side main surface of the yoke plate 3 via an epoxy adhesive.
The coiled thin wire is wound around the cylindrical projecting portion 33 a predetermined number of times. Specifically, a coil thin wire coated with a thermosetting resin is wound a predetermined number of times around the cylindrical projecting portion 33 of the yoke plate 3, and the adjacent coil thin wires are welded by alcohol or heating.

In assembling the above-mentioned electromagnetic receiver, first, the yoke plate 3 is processed. That is, the coil 32 is formed by winding a coil thin wire around the projecting portion 33 of the yoke plate 3 a predetermined number of times, and the magnet 31 is adhered to the outer peripheral portion of the yoke plate 3.

Next, the above-mentioned yoke plate 3 is adhered and fixed to the step portion 13 so as to seal the opening on the rear surface side of the cylindrical main body 10, and both ends of the coil 32 are connected to lead terminals.

Next, a resin diaphragm 21 is adhered and fixed from the opening on the front surface of the cylindrical main body 10 using the stepped portion 13, and the first armature 22 is attached to the center of the resin diaphragm 21 by silicone. The first armature 22 is adhered to the central portion of the first armature 22 via a silicone-based adhesive. In addition, the first armature 22 and the second armature 23 are pasted on a resin diaphragm 21 in advance, and the magnetic body diaphragm 2 is attached to the cylindrical main body 1.
It may be adhered and fixed to the zero step portion 13. In particular, as described above, the resin diaphragm 21, the first armature 22, and the second armature 23 are sequentially adhered to the tubular main body 10 because the resin diaphragm 21 has a thickness of about 25 μm. Because the rigidity is inferior, first, after fixing the resin diaphragm 21, the first and second armatures 22 and 23 are attached by attaching the first armature 22 and the second armature 23.
This is because the first and second armatures 22 and 23 can be easily arranged at the center portion (corresponding to the protruding portion 33 of the yoke plate 3) in the tubular main body 10.

Next, a lid 11 having a sound emission hole 12 is arranged and fixed to the upper opening of the cylindrical main body 10.

Finally, the sound adjusting hole 3 formed in the yoke plate 3
4 is attached with an acoustic resistance cloth 35.

With the structure as described above, the cylindrical main body 10,
The space inside the container 1 composed of the lid 11 (the lid on the sound emission side) and the yoke plate 3 (the lid on the back side) is separated from the sound emission side space (cavity) and the back side by the magnetic vibrating plate 2. The space (cavity) is divided into two.

In the initial state, the first armature 21 and the second armature 23 of the magnetic vibrating plate 2 are in a state where the magnetic flux of the ring-shaped magnet 31 is emitted from the protruding portion 33 of the yoke plate 3. The body vibration plate 2 is in a state of being drawn toward the yoke plate 3 with a constant force. In this state, when an alternating current corresponding to an audio signal is supplied to the coil 32, a magnetic flux is generated in the coil 32 in the axial direction thereof, and is combined with the magnetic flux of the magnet 31 described above. The composite magnetic flux is released to 33. Due to the variation of the magnetic flux of the coil 32, a force in a direction of pulling the magnetic diaphragm 2 and a force of separating the magnetic diaphragm 2 work as compared with the initial state,
The magnetic diaphragm 2 generates vibration corresponding to the audio signal.
Specifically, the composite magnetic flux (magnetic flux corresponding to the audio signal) of the coil 32 and the magnet 31 is provided to the first and second armatures 22 and 23 from the projecting portion 33 of the yoke plate 3, and the first and second armatures are provided. Due to the displacement of the armatures 22 and 23, the resin diaphragm 22 vibrates in the vertical direction.

[0039] This vibration causes the air in the sound emitting cavity to vibrate and resonate, and through the sound emitting hole 12,
The sound of the reproduced audio signal is emitted to the front side.

Here, the sound emission hole 12 of the sound emission side cavity is used.
The characteristics of the sound emitted from the main body largely depend on the distance between the protrusion 33 of the yoke plate 3 and the first and second armatures 22 and 23. That is, if the distance between the protrusion 33 of the yoke plate 3 and the first and second armatures 22 and 23 fluctuates, even if the magnetic flux is constant, the first and second armatures 22 and 23 are not affected. This is because the influence of the magnetic force fluctuates.

Variations in the distance between the projecting portion 33 of the yoke plate 3 and the first and second armatures 22 and 23 depend on the processing accuracy of the projecting portion 33 of the yoke plate 3 and the thickness of each adhesive during assembly. However, fluctuations due to mechanical factors can be eliminated by controlling the processing accuracy.

However, the magnetic material diaphragm 2 itself warps due to the difference in thermal expansion coefficient between the materials constituting the magnetic material diaphragm 2 depending on the use environment temperature, and as a result, the change in the use environment temperature causes The distance between the protrusion 33 of the yoke plate 3 and the first and second armatures 22 and 23 fluctuates.

In this respect, in the present invention, the first armature 22 having a smaller coefficient of thermal expansion than the resin diaphragm 22 is attached to the upper surface of the resin diaphragm 21 fixed to the cylindrical main body 10. On the upper surface of the first armature 22, a second armature 23 having a larger thermal expansion coefficient than that of the first armature 22 is attached.

Accordingly, the difference in the coefficient of thermal expansion between the three joints shows that between the resin diaphragm 21 and the first armature 22, the resin diaphragm is lowered at a constant temperature due to the temperature rise. A convex stress is generated. A stress is generated between the first armature 22 and the second armature 23 so that the second armature 23 protrudes upward at a constant temperature due to the temperature rise.

Therefore, in the magnetic vibrating plate 2 composed of the three members, the above-mentioned two stresses work so as to cancel each other, and the state as shown in FIG. In addition, it is FIG. 3 at the time of normal temperature, and the dotted line in FIG.
4 shows a plane position of the resin diaphragm 21 of FIG. 3. That is, FIG.
In this case, even though the temperature is constant at the time of temperature rise, at least the central portion of the resin diaphragm 21, that is, the portion where the second armature 23 is adhered, has the resin diaphragm 21 shown in FIG. Can be effectively restored to the plane position.

Therefore, the first and second armatures 22,
The distance between the protrusion 23 and the projecting portion 33 of the yoke plate 3 that emits the magnetic flux for exciting the first and second armatures 22 and 23 can be kept close to normal temperature.

The present inventor has described the structure of the present invention,
That is, the variation in the interval between the central portion of the resin diaphragm and the projecting portion of the yoke plate due to a change in the use environment temperature with the magnetic diaphragm having the structure in which the second armature 23 of the present invention is not adhered,
The measurement was performed while raising the temperature to 80 ° C. based on normal temperature (25 ° C.).

In the present invention, at 80 ° C., the state as shown in FIG. 2 is obtained.
Met. On the other hand, in the prior art, 85
A maximum variation of 60 μm was found at ° C. FIG. 4 shows this state.

The specific material of the magnetic diaphragm 2 was the same as that shown in the embodiment.

The maximum fluctuation amount in the present invention is controlled by controlling the thermal expansion coefficient by changing the material of the first and second armatures 22 and 23, and controlling the thickness and shape of the first and second armatures 22 and 23. Substantial fluctuations can be eliminated by making appropriate selections.

The relationship between the thermal expansion coefficients of the resin diaphragm, the first armature, and the second armature is “large”, “small”, and “large” from the resin diaphragm. Occurs sufficiently. For example, if the relationship between the respective coefficients of thermal expansion is “large”, “medium”, and “small” from the resin diaphragm, the warpage due to the constant temperature at the time of raising the temperature becomes larger than the state of the related art shown in FIG.

Even if two armatures are separately adhered to both main surfaces of the resin diaphragm, they are thermally stable,
Since the armature of the two magnetic metal members is divided into two parts via the resin film of the nonmagnetic material, the armature cannot sufficiently act on the magnetic flux emitted from the protruding portion of the yoke plate 3. This is not preferable because it merely increases the weight of the diaphragm.

In the above-described embodiment, the container 1 is composed of three members, ie, the cylindrical body 10, the lid 11, and the yoke plate 3, and the yoke plate is fixed by the step portion 13. The structure of the yoke plate 3 can be variously changed. Further, in the embodiment, two armatures are stacked, but a third armature may be attached on the second armature so as to further reduce warpage due to a difference in thermal expansion coefficient.

[0054]

As described above, according to the electromagnetic receiver of the present invention, as the magnetic vibrating plate, a resin vibrating plate, and the first armature having a smaller coefficient of thermal expansion than the coefficient of thermal expansion of the resin vibrating plate. Since the second armature having a larger coefficient of thermal expansion than that of the first armature is stuck, even if the temperature of the use environment changes, the stress generated by the difference between the coefficients of thermal expansion of these materials is canceled. Since they act in conformity with each other, fluctuations in the distance between the magnetic vibrating plate and the yoke plate can be substantially suppressed, so that the electromagnetic receiver can suppress variations in sound pressure characteristics.

[Brief description of the drawings]

FIG. 1 is a sectional structural view of an electromagnetic receiver of the present invention.

FIG. 2 is a schematic diagram showing a warped state of a magnetic vibrating plate at a constant temperature during a temperature rise used in the electromagnetic receiver of the present invention.

FIG. 3 is a schematic view showing a warped state of a magnetic diaphragm at room temperature used in the electromagnetic receiver of the present invention.

FIG. 4 is a schematic diagram showing a warped state of a magnetic vibrating plate at a constant temperature during a temperature rise used in a conventional electromagnetic receiver.

[Explanation of symbols]

 1 ... Container 10 ... Cylindrical body 2 ... Magnetic vibration plate 21 ... Resin vibration plate 22 ... First armature 23 ... Second Armature 3 ... Yoke plate 33 ... Protrusion 31 ... Magnet 32 ... Coil

Claims (1)

[Claims] 1. A first disk-shaped armature and a first disk-shaped armature on a resin vibration plate inside a resin-made casing having a sound emission hole on a front surface and an open back surface. A magnetic diaphragm, in which a second disk-shaped armature smaller than the diameter is sequentially attached, is disposed, and a magnet and a coil are disposed at an opening on the back surface of the container, where a magnet and a coil for generating excitation are disposed. In the electromagnetic receiver in which the body yoke plate is arranged, the first disk-shaped armature has a thermal expansion coefficient smaller than that of the resin diaphragm, and the second disk-shaped armature has a thermal expansion coefficient smaller than that of the resin diaphragm. An electromagnetic receiver, wherein the coefficient is larger than that of the first disk-shaped armature.