JPH01194799A - Speaker - Google Patents

Abstract

PURPOSE:To improve the electro-acoustic transducing efficiency by pro viding plural superconductive coils coaxially in the plane that shields the magnetic field between a permanent magnet fixed on the base and a permanent magnet fixed on a cone, flowing a current through an arbitrary one of the coils to break the superconducting state and thus vibrating the cone. CONSTITUTION:The permanent magnet 3 is fixed on the base (casing body) 1 made of ceramic. In the middle part of the cone 2 whose peripheral part is fixed on the casing 1, the permanent magnet 4 is fixed therein. The magnets 3 and 4 face to each other at their respective unlike poles, and on a supporting body 6 provided between said two magnets 3, 4, the coils 5 made of superconductive material are provided coaxially. In either of the superconductive coils 5, a current is made flow through in accordance with a voice signal to secure an ever-conducting state. As a result, an acoustic wave is driven to its high frequency band with a regular power, hence the electro-acoustic transducing efficiency can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a speaker, and particularly to a speaker with improved conversion efficiency.

[Conventional technology]

In a conventional speaker of this type, a coil having a central axis substantially perpendicular to the surface of the cone is integrally attached to the center of the cone, and the coil is disposed within a magnetic gap of a magnetic circuit.

In a speaker having such a configuration, when an audio signal current is passed through the coil, since the coil is disposed in the magnetic field of the magnetic gap, it receives a force corresponding to the audio signal current in the direction of its central axis, and this This causes the cone to vibrate.

[Problem to be solved by the invention]

By the way, in such conventional speakers, in order to vibrate the cone, a corresponding driving force must be obtained from a coil placed within the magnetic field of the magnetic gap in the magnetic circuit. It is conceivable to increase the number of turns of the coil in order to increase the driving force obtained from the coil, but increasing the number of turns of the coil in this way increases the inductance component of the coil, making it difficult to drive the high frequency range of the audio signal. The problem is that it cannot be done. On the other hand, when trying to reduce the inductance component of the coil, it is necessary to reduce the number of turns in the coil, but in order to obtain sufficient driving force from the coil, the magnetic field in the magnetic gap becomes stronger. Or it needs to be driven by a large audio current. However, there is a problem in that there is a limit to how strong the magnetic field can be, and there is also a limit to driving with a large current due to the thickness of the coil winding.

The present invention has been made to solve the problems of the prior art described above, and an object of the present invention is to provide a speaker that can be driven over a wide range with a constant current.

[Means to solve the problem]

A speaker according to the present invention that achieves the above object includes a first permanent magnet fixed to a base, and a second permanent magnet arranged opposite to the first permanent magnet with a polarity different from the first permanent magnet and fixed to a cone. , consisting of a plurality of superconducting coils arranged concentrically in a plane that blocks the magnetic field between the first permanent magnet and the second permanent magnet, and superconducting by passing a current through any one of the superconducting coils. The cone is configured to vibrate by breaking the state.

[Effect]

In speakers with this configuration, are they arranged concentrically in the same plane? IJF's superconducting coil can be magnetically shielded by the Meissner effect. This superconducting coil may be any one of the plurality of superconducting coils (
By passing a current higher than the critical current through the coil (or two appropriately selected coils), the superconducting state can be broken, and its magnetic shielding function can be weakened or lost.

Therefore, the second permanent magnets disposed opposite to the fixed first permanent magnet with different polarities attract each other due to the loss of the magnetic shielding function of the superconducting coil. As a result, the cone can be arbitrarily vibrated by increasing or decreasing the magnetic shielding function of the plurality of superconducting coils.

Therefore, by passing current through any one of the plurality of superconducting coils, it is possible to impart any vibration to the second permanent magnet and generate the sound of the cone that fixes the second permanent magnet. .

According to the present invention configured in this way, the number of turns constituting the superconducting coil as a magnetic shield can be significantly reduced, so the inductance can be reduced (also, according to the present invention, constant power can be reduced). Based on this, it becomes possible to drive up to high frequencies.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a sectional view showing an embodiment of a speaker according to the present invention;
FIG. 2 is a sectional view taken along the line ■--■ in FIG.

In these figures, there is a housing 1 made of, for example, ceramic. A cone 2 is supported at the open end of the housing 1 by fixing its peripheral portion. When the open end of the housing l is circular, the cone 2 has a conical shape, and its top is positioned within the housing l.

A first permanent magnet 3 is fixedly disposed on the inner wall surface of the housing 1 facing the top of the cone 2, and its S pole face faces the top of the cone 2. A second permanent magnet 4 is fixed to the top of the cone 2, with its north pole facing the first permanent magnet 3. Thereby, the first permanent magnet 3 and the second permanent magnet 4 are positioned in a mutually attracted relationship.

Thus, the center of the opposing surface of the first permanent magnet 3 and the second permanent magnet 4 passes through the surface that blocks the magnetic field between the first permanent magnet 3 and the second permanent magnet 4. A plurality of superconducting coils 5 are arranged concentrically around the axis. This superconducting coil 5 is made of yttrium (Y-Ba-C), for example.
u-0) Oxidation method bismuth system (B i-S r-Ca-C
u-0) It is composed of a wire made of a superconducting material such as an oxide.

The plurality of superconducting coils 5 arranged concentrically are
As shown in the figure, both ends are pulled out in one direction and connected to terminals (not shown) of the housing 1.

In addition, each superconducting coil (in the same figure, C8°Cz, C
s, . . . , C7) are supported by an unillustrated support (preferably made of a material that does not affect the magnetic field) to maintain a concentric arrangement.

The operation of the embodiment configured in this way will be explained.

According to the speaker configured as described above, each superconducting coil C,, CA, C1,..., C7 is in a superconducting state and has the strongest magnetic shielding function, and the first permanent The lines of magnetic force coming out of the magnet 3 and the lines of magnetic force coming out of the second permanent magnet 4 cannot merge, but are in static balanced positions with respect to each other.

Therefore, if a digital signal consisting of, for example, n bits is used as the acoustic signal, if the lowest bit is logic "1", it will flow to the superconducting coil C1,
When the most significant bit is logic "1", current is caused to flow through the superconducting coil C7.

The superconducting state of the superconducting coil is broken in that part where the current flows, lines of magnetic force enter, and the first permanent magnet 3 and the second permanent magnet 4 are attracted to each other depending on the degree of the lines of magnetic force. .

In the embodiments described above, the housing 1 is made of a material such as ceramic, but it may be made of a superconducting material.

In this way, magnetic flux leakage between the first permanent magnet 3 and the second permanent magnet 4 can be prevented.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to drive in a high band with a constant amount of electric power. Further, according to the present invention, there is also an effect that the electricity-to-sound conversion efficiency of the speaker is increased.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line ■-■ in FIG. DESCRIPTION OF SYMBOLS 1... Housing, 2... Cone, 3... First permanent magnet, 4... Second permanent magnet, 5... Superconducting coil. Agent Patent Attorney Tomo Murakami - Figure 1 Figure 2

Claims (1)

[Claims] (1) A first permanent magnet fixed to the base; a second permanent magnet arranged opposite to the first permanent magnet with a different polarity and fixed to the cone; It consists of a plurality of superconducting coils arranged concentrically in a plane that blocks the magnetic field between two permanent magnets, and the cone is vibrated by passing current through any one of the superconducting coils to break the superconducting state. A speaker characterized in that it has a configuration in which it can be controlled.