JPS592239B2 - Movable magnet speaker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a movable magnet type speaker that is small in size, lightweight, highly reliable, and has high power durability.

Conventionally, a movable ring type speaker that has been widely used in practical use includes, for example, a yoke 1 having an inverted T-shaped cross section, a permanent magnet 2 disposed on the yoke 1, as shown in FIG.
A magnetic circuit is formed by a plate 3 disposed on the permanent magnet 2, and a magnetic circuit is formed by the plate 3 disposed opposite the central upper end of the yoke 1 and its circumferential surface with a slight distance therebetween. In the center of the formed magnetic gap 4,
A cylindrical moving coil 5 is disposed, and this moving coil 5 is supported by a damper 6 and a cone 7 is integrally connected thereto.

When an audio current is passed through a lead wire 8 whose one end is connected to a cone 7, an electromagnetic force is generated in the moving coil 5 due to Fleming's left hand rule, causing it to vibrate up and down in the state shown. The cone 7 is configured to vibrate and generate sound.

However, in this type of speaker, the magnetic circuit is made up of members such as the yoke 1, the permanent magnet 2, and the plate 3, so it becomes large in size, and as a result, the main body of the speaker also becomes large and its weight increases. It had the following drawback.

In addition, the connecting portion 9 of the lead wire 8 connected to the cone 7 is integral with the movable coil 5 and the cone 7 and constantly vibrates during driving, so there is a drawback that disconnection failure easily occurs.

Furthermore, since the moving coil 5 is simply disposed approximately in the center of the magnetic gap 4 without contacting other members, it has poor heat dissipation and cannot withstand large amounts of power.
The number of turns is limited because the mass of the cone 7 must be reduced to prevent a decrease in the vibration efficiency of the cone 7, and it must be placed in the minute gap formed by the plate 3 and the yoke 1. There was a problem in that the input signal applied to the coil 5 was also limited.

The present invention improves the above-mentioned drawbacks, and attempts to reduce the size of the magnetic circuit by combining a core with a specially shaped coil and a movable magnet with a cone that is arranged to vibrate with respect to the core. The object of the present invention is to provide a movable magnet type speaker that prevents breakage of lead wires due to vibration, improves heat dissipation of the coil, and allows large input signals to be applied to the coil. be.

The present invention will be described in detail below with reference to the drawings.

FIG. 2 shows an embodiment of the present invention, in which the core 10 has a substantially bobbin-like shape as a whole, a substantially square-shaped cross section, and is appropriately fixed to a frame (not shown).

This core 10 is made of, for example, silicon steel with low hysteresis loss, and has two annular grooves 11 in its main body.
is formed.

Therefore, flange-shaped magnetic legs are formed by these grooves 11 in the upper, lower, and center portions of the core 10, respectively.

In each of the grooves 11, an excitation coil 12 is wound.

When these coils 12 are excited by passing an audio current, both ends of the core, that is, the upper and lower magnetic legs, are magnetized with the same polarity, while the magnetic leg in the center is magnetized with a different polarity from the upper and lower magnetic legs. It is rolled.

In addition, a protrusion 13 that slightly protrudes inward is formed at the inner tip of the upper and lower magnetic legs, and protrusions 13 that slightly protrude in the vertical direction are formed on both sides of the tip of the central magnetic leg. 13 is formed.

This is intended to protect the coil 12 wound around the annular groove 11 and to reduce magnetic resistance as will be described later, thereby inducing the operation of the movable magnet.

A movable magnet 14 made of, for example, a rare earth cobalt magnet that is small, lightweight, and has a high coercive force is attached to the circumferential surface of the core 10.
It is arranged so that it can be moved up and down.

A cone 15 is integrally provided at the upper end of the movable magnet 14, and the upper end is magnetized, for example, to the N pole, and the lower end is magnetized to the S pole, and is formed into a ring shape as shown in FIG. ing.

However, the shape of the movable magnet 14 is not limited to this embodiment, and as shown in FIG. It is also possible to use one formed by

Although the movable magnet 14 and/or the cone 15 are not particularly shown, they are supported so as to be able to vibrate as appropriate by a tamper, as is well known.

Further, the other configurations are substantially the same as those of the conventional example.

Next, the present invention will be explained in detail.

When no audio current is applied to coil 12, core 1
Since the upper and lower magnetic legs of 0 are not magnetized with specific magnetic poles, the magnetic forces of both poles of the movable magnet 14 act equally on the upper and lower magnetic legs.
Also, since it is supported by the tamper, the movable magnet 1
4 does not move and remains stationary at approximately the center of the core 10.

Now, when an audio current is applied to the coil 12 to excite it, for example, the magnetic legs of the core 10 are magnetized to 5-N-8 (N-8-N) poles from the upper magnetic legs for a positive half cycle of the audio current. The movable magnet 14 and the upper magnetic leg, which are disposed in a non-contact manner with respect to the core 10, attract each other and the lower magnetic leg repel each other, so that the movable body consisting of the movable magnet 14 and the cone 15 is
Move in direction A in the figure.

On the other hand, for the negative half cycle of the audio current, the core 10
Contrary to the above, the magnetic legs are N-8-N from the upper magnetic legs.
(SN-8) magnetized, the movable magnet 14 and the upper magnetic leg repel each other, and the lower magnetic leg attracts each other, so that the movable body moves in the direction B in FIG. 2.

In this way, the movable magnet 14 vibrates in accordance with the sound current, and the cone 15 joined to the movable magnet 14 also vibrates together at the same time, so that a sound wave is emitted from the cone 15.

FIG. 5 shows another embodiment of the present invention. In this embodiment, a movable core having a core, ten upper and lower magnetic legs extending in the diametrical direction, and the outer diameter of which is disposed on the circumferential surface of the core 10, is used. This embodiment differs from the previous embodiment shown in FIG. 2 in that it is formed to have approximately the same diameter as the outer diameter of the magnet 14, and the end face of the movable magnet 14 and the inner surface of the magnetic leg are opposed to each other.

In this case, since the outer diameters of the magnetic pole end face of the movable magnet 14 and the upper and lower magnetic legs of the core 10 are approximately the same and are opposed to each other, magnetic resistance is reduced and the efficiency of converting audio current into sound waves is increased.

Note that the other configurations and operations are substantially the same as those of the above-described embodiments, so the same parts are designated by the same reference numerals, and detailed explanations are omitted to avoid duplication of explanation. This shows another embodiment, in which a magnetic material 16 with high magnetic permeability, such as soft iron, is used.
are coupled to both upper and lower end surfaces of the ring-shaped movable magnet 14.

In this case, the movable magnet 14 is substantially extended in the vertical direction by the magnetic body 16 joined to the movable magnet 14, so the magnetic path formed by both poles of the movable magnet 14 and the upper and lower magnetic legs of the core 10 (in the figure Since the magnetic reluctance at the point (indicated by the broken line) can be reduced, there is an effect similar to that of the embodiment described above.

In the above description, the case where the movable magnet 14 and the core 10 are substantially cylindrical is described, but it is of course possible to use polygonal magnets.

As described above, the present invention forms at least two or more annular grooves for coil winding on the circumferential surface of the core, and also forms a plurality of magnetic legs to give the core a special shape. A coil is wound so that the magnetic legs at both ends are magnetized to the same polarity, and movable magnets having mutually different magnetic poles at the ends in the axial direction are arranged around the core so as to be able to vibrate. ,
The number of parts that make up the magnetic circuit has been reduced compared to the conventional example, making the magnetic circuit smaller and lighter, making it easier to handle, and since the coil is wound in an annular groove, it can be used with a plate instead of the conventional one. The number of turns of the coil can be increased compared to the case where the coil is placed in a small gap with the yoke, and restrictions on the input signal applied to the coil can be eliminated.

Further, since the present invention does not have a structure in which a lead wire is disposed in a movable part, it is possible to prevent breakage of the lead wire due to vibration of the moving coil as in conventional speakers.

Furthermore, as described above, in the present invention, since the annular groove is provided on the circumferential surface of the core to form a large heat dissipation area, the heat of the coil can be efficiently dissipated through the core, and there are effects such as being able to withstand large inputs. .

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view showing a conventional movable linear ring speaker, FIG. 2 is a longitudinal sectional view showing an embodiment of the movable magnet speaker of the present invention, and FIG. 3 is a perspective view of the movable magnet. , FIGS. 4 to 6 show other embodiments of the present invention,
FIG. 4 is a perspective view showing another embodiment of the movable magnet, FIG. 5 is a longitudinal sectional view showing another embodiment of the core, and FIG. 6 is a perspective view showing another embodiment of the movable magnet in relation to the core. FIG. 10... Core, 11... Annular groove, 12
......Coil, 14...Movable magnet.

Claims (1)

[Claims] 1. A groove for coil winding (formerly r prefecture-shaped) is formed on the circumferential surface,
a core made of a substantially bobbin-shaped ferromagnetic material on which a plurality of magnetic legs are formed; a coil wound in an annular groove of the core so that the magnetic legs at both ends are magnetized to the same polarity; A movable magnet, characterized in that it is provided with a substantially ring-shaped movable magnet that is vibrably disposed around the core, has mutually different magnetic poles at the ends in the axial direction, and is coupled with a cone. Magnetic speaker. 2. The movable magnet type speaker according to claim 1, wherein a magnetic material with high magnetic permeability is bonded to both ends of the movable magnet. 3. A magnetic leg medically formed with an annular groove is formed on the circumferential surface of the core, and the outer diameter of the magnetic leg that sandwiches the movable magnet among the magnetic legs is formed to be approximately the same diameter as the outer diameter of the movable magnet. The movable magnet type speaker according to item 1. 4. The movable magnet type speaker according to claim 1, wherein the movable magnet is formed by arranging a large number of bar-shaped magnets in a ring shape.