JPH0336160Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a speaker that vibrates a diaphragm in response to a signal current flowing through a voice coil to obtain an acoustic output.

[Background technology and its problems]

Generally, as this type of speaker, a dynamic type speaker having a structure as shown in FIG. 1 has been widely known. That is, in a conventional dynamic speaker, a voice coil 4 through which a signal current flows is located in a magnetic gap 3 formed in a magnetic circuit 2 having a magnet 1, and the voice coil 4 is mechanically attached to a diaphragm 5. The diaphragm 5 is fixedly attached to the diaphragm 5 by the interaction between the magnetic field applied by the magnet 1 to the magnetic gap 3 of the magnetic circuit 2 and the magnetic field generated by the voice coil 4 in response to the signal current. It was starting to drive.

In the conventional dynamic type speaker having the structure as described above, the voice coil 4, which has a relatively large mass, is attached and fixed to the diaphragm 5, and since the voice coil 4 vibrates together with the diaphragm 5, the transient response characteristics of the vibration system and The high frequency characteristics are voice coil 4 above.
The disadvantage is that it deteriorates depending on the mass of the Also,
There is a drawback that the lead wire 4a that supplies the signal current to the voice coil 4 is easily fatigued and broken by the vibration of the voice coil 4. Furthermore, since the diaphragm 5 to which the voice coil 4 is attached is generally made of paper or the like having high thermal resistance, the heat generated in the voice coil 4 due to the signal current is difficult to radiate and diffuse. It is difficult to increase the allowable electrical input of 4.
Further, due to the vibration and heat generation, the state in which the voice coil is mechanically fixed to the diaphragm also lacks reliability. Furthermore, the magnet 1 provided in the magnetic circuit 2 is generally expensive, which inevitably increases the cost of the speaker.

[Purpose of invention]

Therefore, the present invention solves various problems in conventional dynamic type speakers as described above by providing the voice coil on the fixed side to drive the diaphragm without providing a voice coil on the diaphragm. The present invention provides a speaker with a new configuration.

[Summary of the idea]

In order to achieve the above-mentioned object, the speaker according to the present invention includes a diaphragm made of a thin plate-shaped conductive material whose peripheral part is supported by a fixed part and whose central part is freely vibrating, and a magnetic flux in a direction perpendicular to the diaphragm. and a fixed voice coil that generates a signal current in response to a signal current, and generates an eddy current in the diaphragm due to changes in the magnetic flux generated by the voice coil, so that the magnetic flux generated by the eddy current and the magnetic flux generated by the voice coil interact with each other. The present invention is characterized in that the diaphragm is driven by the action.

〔Example〕

Hereinafter, one embodiment of the speaker according to the present invention will be described in detail with reference to the drawings.

In the speaker of the embodiment shown in FIG. 2, the diaphragm 11 is made of a thin plate-shaped conductive material such as aluminum foil or copper foil. 14
It is attached to and supported so that it can vibrate freely. The voice coil 15 is attached and fixed to the frame 13, and is also wound around and adhesively fixed to a yoke 16 having an end surface 16A facing the diaphragm 11, and receives a signal current Iv flowing through the lead wire 15a. Accordingly, a magnetic flux φv in a direction perpendicular to the diaphragm 11 is generated.

In the embodiment with the above configuration, the lead wire 1
When the signal current Iv supplied to the voice coil 15 through 5a changes, the magnetic flux φv generated by the voice coil 15 also changes. Then, as schematically shown in FIG. 3, an eddy current Ie is generated in the diaphragm 11 made of a conductive material due to a change in the magnetic flux φv due to the voice coil 15, and a secondary magnetic flux due to this eddy current Ie φe is generated, and the interaction between the magnetic flux φe due to the eddy current Ie and the magnetic flux φv due to the voice coil 15 gives a vibration force F. Therefore, the diaphragm 11 is driven according to the signal current Iv flowing through the voice coil 15.

In the embodiment configured as described above, the voice coil 1
5 is fixed to the fixed side, that is, to the frame 13, the voice coil 15 does not vibrate and there is no risk of fatigue breaking of the lead wire 15a, and the heat generated by the signal current is transferred to the frame 13.
Heat can be dissipated efficiently through the heat exchanger, and the allowable electrical input can also be increased. Furthermore, since no unnecessary increase in mass is given to the diaphragm 11, the transient response of the oscillation system to the signal current and the high frequency reproduction characteristics can be improved. Furthermore, since a magnetic circuit equipped with an expensive magnet is not required, the cost of the speaker can be reduced and the speaker can be made smaller.

In the above embodiment, the diaphragm 11 is driven by one voice coil 15, but a plurality of voice coils each generate magnetic flux in a direction perpendicular to the diaphragm to drive the diaphragm 11. It is also possible to drive the

Further, as in the embodiment shown in FIG. 4, a donut-shaped yoke 26 having a C-shaped longitudinal section is used to direct the magnetic flux φv generated by the voice coil 25 between the ring-shaped end surfaces 26A and 26B of the yoke 26. A diaphragm 21 made of a conductive material and focused in a magnetic air gap 27
If the magnetic field is located in the magnetic gap 27, the driving efficiency can be improved. In this embodiment, the yoke 26 also serves as a frame that supports the diaphragm 21.

Further, in each of the above-mentioned embodiments, the present invention is applied to a flat speaker, but as in the embodiment shown in FIG. The flat part 3 is formed by
The magnetic flux φv in the direction perpendicular to 1A is transferred to the voice coil 3.
A cone-type speaker may be constructed by giving the following information.

[Effect of idea]

As is clear from the description of the embodiments described above, in the speaker according to the present invention, the diaphragm made of a conductive material is driven by an eddy current generated by a fixed voice coil in the diaphragm, so that the characteristics of the vibration system are In addition to improving heat dissipation and mechanical installation of the voice coil,
We can provide high-performance, compact speakers at low cost.
The intended purpose can be fully achieved.

[Brief explanation of the drawing]

FIG. 1 is a schematic vertical sectional view showing a conventional example of a dynamic type speaker. FIG. 2 is a schematic vertical sectional view showing an embodiment of the speaker according to the present invention. FIG. 3 is a schematic diagram for explaining the principle of driving the diaphragm in the above embodiment. FIG. 4 is a schematic vertical sectional view showing another embodiment of the present invention. FIG. 5 is a schematic vertical sectional view showing still another embodiment of the present invention. 11, 21, 31...Diaphragm, 13...Frame, 15,25,35...Voice coil, 16,
26...York.

Claims (1)

[Scope of utility model registration request] It is equipped with a diaphragm made of a thin plate-shaped conductive material whose peripheral part is supported by a fixed part and whose central part can freely vibrate, and a fixed voice coil that generates magnetic flux in a direction perpendicular to the diaphragm in response to a signal current. An eddy current is generated in the diaphragm due to a change in the magnetic flux generated by the voice coil, and the diaphragm is driven by the interaction between the magnetic flux due to the eddy current and the magnetic flux due to the voice coil. speaker.