JPH01274600A - Speaker - Google Patents

Abstract

PURPOSE:To improve the heat dissipation of a conductor part and to facilitate mount/removal of a diaphragm by forming a damper supporting in vibration free the diaphragm mounted to a magnetic circuit incorporatedly with the conductor part. CONSTITUTION:An aluminum made dome type diaphragm 2 has an annular conductor part 8 and a damper 9 incorporated with the conductor part 8 at its opening ridge 7. The diaphragm 2 supports the conductor part 8 at the magnetic air gap 10 and is supported by the damper 9 in vibration free. In case of applying an AC current to a power coil 3, an induction current flows to the ring shaped conductor part 8, it is heated by its resistive component and dissipated through the damper 9. Since the damper 9 and the diaphragm 2 are incorporated together, the mount/removal to/from the late 4 is facilitate.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to loudspeakers, particularly inductive loudspeakers.

[Summary of the invention]

A speaker according to the present invention includes a diaphragm having an annular conductive part, a power supply coil disposed to face the R-shaped part with a predetermined gap, and a magnetic circuit to which the power supply coil is attached, It is characterized in that a damper that is attached to the magnetic circuit and supports the diaphragm so as to vibrate freely is formed integrally with the conductive part.

Therefore, heat can be efficiently dissipated from the damper, and the attachment and detachment of the diaphragm becomes extremely easy.

[Conventional technology]

In conventional speakers, particularly inductive speakers, driving force is obtained by passing an audio signal current through a voice coil in a DC magnetic field. This audio signal current is normally supplied to the voice coil from the outside through a lead wire fixed to a paper cone serving as a diaphragm.

[Problem to be solved by the invention]

As mentioned above, in the conventional induction type speaker, an audio signal current is externally supplied to the voice coil through a lead wire in order to obtain driving force.

However, conventional induction type speakers equipped with such lead wires have a drawback in that the lead wires are easily cut due to the reciprocating movement of the diaphragm. On the other hand, even if the lead wire is not cut, the linearity of the reciprocating motion of the diaphragm is inhibited, which tends to cause sound distortion, and the lead wire itself resonates, producing abnormal noise. there were. Furthermore, during manufacturing, the lead wire must be pulled out through a narrow gap in the speaker, positioned, and then glued and fixed, making assembly difficult.

Therefore, in order to eliminate the various drawbacks mentioned above, an inductive type speaker with the lead wire removed was developed under the Japanese Patent Publication No. 56-27039.
It is disclosed in the publication No. In the induction type speaker disclosed in the above-mentioned publication, the lead wire is removed and a drive coil is arranged near the voice coil wound around the voice coil bobbin. An audio signal current is supplied to this drive coil, and the audio signal is supplied from this drive coil to the voice coil by magnetic induction. That is, when an AC signal from an audio frequency power amplifier flows into the drive coil, the AC signal generates an AC magnetic flux from the drive coil corresponding to the input waveform, and this AC magnetic flux is closely connected to the voice coil located at a close distance. interlink. On the other hand, since the voice coil itself is short-circuited, a short-circuit current flows through the voice coil due to the above-mentioned alternating current magnetic flux. Since the voice coil is located within the magnetic field created by the pole piece and the surrounding magnetic field, a force proportional to the product of the strength of the magnetic field and the short-circuit current acts on the voice coil. This force passes from the voice coil through the voice coil bobbin and causes the cone formed integrally with the voice coil bobbin to vibrate, and sound is radiated from the cone like a normal speaker.

In the technology disclosed in the above-mentioned publication, the lead wires are removed, so although various drawbacks caused by the lead wires are resolved, the following problems also occur. .

Since the voice coil is generally fixed to the voice coil bobbin with an adhesive, there is a drawback that the driving force generated in the voice coil is difficult to be directly transmitted to the cone.

Furthermore, the voice coil inevitably generates heat due to short-circuit current, but there is a drawback in that it is difficult to properly dissipate this heat.

By the way, in order to improve the sensitivity of a speaker, it is generally required to narrow the gap (magnetic gap) between the coil bobbin and the drive coil, and to wind the voice coil many times within this gap. Ru. Therefore, the diameter of the metal wire used in the voice coil inevitably becomes smaller, and the heat capacity of the metal wire described above becomes smaller. As a result, in addition to the problem of heat dissipation as described above, the voice coil is susceptible to disconnection due to heat generation, resulting in a drawback that the current capacity is limited.

Furthermore, there is a drawback that the paper voice coil bobbin is carbonized due to the above-mentioned heat generation being repeated.

Therefore, an induction type speaker was proposed in Japanese Utility Model Application Laid-Open No. 105438/1983, in which not only the lead wire but also the voice coil was removed. That is, in a magnetic gap in a magnetic circuit, a diaphragm having an annular conductive part is supported by a damper so as to be able to freely vibrate, and a feeding coil is arranged to face the conductive part and electrically coupled to the conductive part by mutual induction. This is what is being set up.

In this speaker, the voice coil is removed by generating an induced current based on mutual induction in an annular conductive portion formed in a portion of the diaphragm.

In the technique disclosed in the above-mentioned publication, not only the lead wire but also the voice coil is removed, so various drawbacks caused by the lead wire, voice coil, etc. are eliminated.

However, the damper that supports the diaphragm generally -
Since it is solidified and formed by impregnating a cloth material with phenol, there is a problem in that the heat generated in the conductive part cannot be dissipated. Also, since the materials of the diaphragm and damper are completely different, they cannot be formed as one piece.
Each time the diaphragm is installed or removed, the damper must also be installed or removed. Therefore, there were problems in that workability was poor and it took a very long time to manufacture and repair.

Therefore, an object of the present invention is to provide a speaker in which a damper and a conductive part are integrally formed.

[Means to solve the problem]

A speaker according to the present invention includes a diaphragm having an annular conductive part, a power supply coil disposed to face the conductive part with a predetermined gap, and a magnetic circuit to which the power supply coil is attached. It is characterized in that a damper that is attached and supports the diaphragm so that it can freely vibrate is formed integrally with the conductive part.

[Effect]

When an alternating current as an audio signal is passed through the power feeding coil, an alternating current magnetic flux is generated, and based on the interlinkage magnetic flux, an induced current of the same frequency is induced in the annular conductive part due to a mutual induction phenomenon. The induced current in the conductive portion acts on the DC magnetic field at the position of the magnetic gap, excites the diaphragm, and emits sound waves.

At this time, since an induced current flows through the conductive part, heat is generated by the resistance component of the conductive part. However, this heat is transferred from the conductive part to the damper, and this damper efficiently
Dissipated. Furthermore, since the conductive part and the damper are integrally formed, it does not take much time to attach and remove the diaphragm, and work efficiency is greatly improved.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. In this embodiment, the present invention is applied to a dome-shaped speaker as shown in FIGS. 1 to 4. Note that this explanation will be made in the following order.

(A) About the first embodiment (B) About the second embodiment (C) About the modification (A) About the first embodiment FIGS. 1 and 2 show a first embodiment according to the present invention. has been done. In the configuration shown in FIG. 1, the speaker 1 mainly includes a diaphragm 2, a primary feeding coil 3, a plate 4, a magnet 5, and a yoke plate 6.

The dome-shaped diaphragm 2 has an annular conductive portion 8 at an opening edge 7 and a damper 9 integrally formed with the i-shaped portion 8 . The diaphragm 2 is entirely made of a thin plate-like good conductor such as aluminum, beryllium, magnesium, or the like. The diaphragm 2 is supported by a damper 9 so as to be able to freely vibrate, with the conductive portion 8 located within the magnetic gap 10 . This damper 9 has a spring property and is formed in an annular shape around the conductive part 8.
Fixed on top. The magnetic gap 10 described above is formed in an annular shape between the plate 4 and the pole piece 11 of the yoke plate 6.

The primary feeding coil 3 electrically couples the annular conductive portion 8 by mutual induction, and is disposed opposite to the conductive portion 8 with a predetermined gap therebetween. This primary feeding coil 3 is disposed facing a position corresponding to the outer periphery or a position corresponding to the inner periphery of the conductive portion 8.
The secondary feeding coil 3 is fixed to one end surface 12 of the plate 4 so as to correspond to the outer periphery of the annular conductive portion 8 . Further, when the primary feeding coil 3 is provided at a position corresponding to the inner circumference of the conductive portion 8, it is fixed to the outer circumference 13 side of the pole piece 11. Note that the primary feeding coil 3 may be provided both at a position corresponding to the outer periphery or at a position corresponding to the inner periphery of the conductive portion 8.

The plate 4, magnet 5, yoke plate 6, and pole piece 11 constitute a magnetic circuit. That is,
As shown in FIG. 1, a magnet 5 is fixed to the outer periphery of the yoke plate 6, and the plate 4 is fixed to the outer periphery of the magnet 5. A magnetic circuit is formed along a path from the magnet 5 to the plate 4, from the magnet 5 to the yoke plate 6, and then to the pole piece 11 of the yoke plate 6 across the magnetic gap lO.

Next, an example of the state in which the diaphragm 2 is formed will be explained with reference to FIG. 2.

First, the opening edge 15 of the cylindrical body 14 as shown in FIG. 2A is folded back to form an annular peripheral edge 16 as shown in FIG. 2B.

Next, a damper 9 having spring properties is attached to the above-mentioned peripheral portion 16.
is formed in a ring shape. At this time, an annular fixing portion 17 for the plate 4 is also formed.

This forms the diaphragm 2.

The means for forming the diaphragm 2 may be selected from a press or other suitable means.

Next, the operation of this speaker 1 will be explained.

When an alternating current as an audio signal is passed through the primary feeding coil 3, an alternating magnetic flux corresponding to a human power waveform is generated. Based on the resulting interlinkage magnetic flux, induced currents of the same frequency are induced in the annular conductive portion 8 due to a mutual induction phenomenon. This N1.
Since the portion 8 is located within the magnetic gap 10, a force proportional to the product of the DC magnetic field strength and the induced current in the magnetic gap lO acts on the conductive portion 8, that is, the conductive portion 8 acts on the conductive portion 8. The induced current in the section 8 interacts with the DC magnetic field in the magnetic gap section 10 to directly drive the diaphragm and emit sound waves.

At this time, since an induced current flows through the conductive part 8, the conductive part 8
Heat is generated by the resistance component of However, this heat is transmitted from the conductive portion 8 to the damper 9 and is dissipated by the damper 9.

By the way, in the high-frequency region of the audio signal, the reciprocating motion of the diaphragm 2 is relatively small (although, since the damper 9 has spring properties, it can sufficiently follow the reciprocating motion of the diaphragm 2. Since the damper 9 is also integrally formed with the diaphragm 2, it is easy to attach and detach it from the plate 4.

In this speaker 1, the diaphragm 2 as the vibration system and the primary feeding coil 3 as the fixed side are mechanically separated and electrically coupled by mutual induction.
It can be operated without disposing conventional voice coils, voice coil bobbins, lead wires, etc.

Therefore, since the conductive portion 8 as a driving force generation source can be integrally formed with the diaphragm 2, all problems associated with their coupling can be solved.

In other words, cutting of the lead wire, generation of abnormal noise due to resonance of the lead wire, interference with linearity due to the lead wire and generation of sound distortion, indirect transmission of driving force by voice coil adhesive, voice coil This solves problems such as wire breakage due to heat and carbonization of the voice coil bobbin. As a result, excellent vibration characteristics and sound quality can be obtained, and it is possible to have a wide degree of freedom in acoustic characteristics.

(B) Second Embodiment This second embodiment differs from the first embodiment in the method of forming the diaphragm 20.

FIG. 3 shows an example of the formation of the diaphragm 20 in the second embodiment. In FIG. 3A, a hemisphere 21 is shown, and the third
An annular plate 22 is shown in Figures B and 3C, respectively.

As shown in FIGS. 3D and 3E, this plate 22 includes an annular conductive part 23, a damper 24, and a fixing part 25.
are formed respectively.

Next, as shown in FIG. 3F, the hemisphere 21 and plate 22 are connected to form the diaphragm 20.

The other configurations and functions are the same as in the first embodiment.
Omit duplicate explanations.

(C) Regarding modified examples FIG. 4 shows a modified example.

This is to prevent the induced current induced in the conductive part 8 from flowing to the damper 9, and as shown in FIG.
is formed in a ring shape.

This cut 31 reduces the area that can conduct electricity, so the resistance value increases relatively.

As a result, the induced current is prevented from flowing into the damper 9, and the current efficiency can be improved.

Note that although the first and second embodiments and the modified examples are explained using a dome-shaped speaker as an example, the present invention is not limited to this and can of course be applied to a cone-shaped speaker as well. be. Furthermore, although the illustrated examples are all external magnet types in which the magnet 5 is arranged on the outer periphery, it goes without saying that the present invention can also be similarly applied to an internal magnet type in which the magnet 5 is arranged in the pole piece 11.

[Effects of the Invention] According to the present invention, the damper that is attached to the magnetic circuit and supports the diaphragm so as to vibrate freely is formed integrally with the conductive part, so that heat generated in the conductive part can be dissipated more efficiently than the damper. It has the effect of being able to This has the effect of increasing the current capacity in the conductive portion of the diaphragm and allowing a larger induced current to flow through the conductive portion. Further, there is an effect that the diaphragm can be attached and detached extremely easily. This has the effect of greatly improving workability during manufacturing and repair.

In addition, since the configuration does not include the conventional voice coil, voice coil bobbin, lead wire, etc., the lead wire may break, lead wire resonance may cause abnormal noise, and the lead wire may interfere with linearity and cause sound distortion. This has the effect of eliminating problems such as the occurrence of noise, indirect transmission of driving force by the adhesive of the voice coil, disconnection of the voice coil due to heat, and carbonization of the voice coil bobbin.

Since the damper has spring properties, it has the effect of improving the ability to follow the reciprocating motion of the diaphragm, especially in high frequencies.

[Brief explanation of the drawing]

1 is a sectional view showing a first embodiment of the present invention, FIG. 2 is an explanatory sectional view showing a method of forming the diaphragm shown in FIG. 1, and FIG. 3 is a sectional view showing a second embodiment. FIG. 4 is a partially enlarged sectional view of a modified example of the present invention. Explanation of main symbols in the drawings 1: Speaker, 2, 20: Vibration plate, 3: Primary feeding coil, 4 Nibrate, 5: Magnet, 6: Yoke plate, 8.23: Conductive part, 9.24: Damper, ll: Pole piece. Agent Patent Attorney Masatoshi Sugiura, v/1 Suhika cross-sectional view Figure 1 Male 4 Figure 2 (1,000 planes straight ahead) (Explanatory diagram of LtIt plane) Figure 3

Claims (1)

[Scope of Claims] A diaphragm having an annular conductive part, a power supply coil disposed to face the conductive part with a predetermined gap, and a magnetic circuit to which the power supply coil is attached, the magnetic circuit comprising: A speaker characterized in that a damper that is attached to and supports the diaphragm so as to vibrate freely is formed integrally with the conductive part.