JPS5811799B2 - speaker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a speaker having a plurality of vibration systems, such as a flat speaker, and particularly aims to prevent resonance during driving thereof.

FIG. 1 is a linear plan view showing an example of a flat speaker to which the present invention can be applied, and FIG. 2 is a longitudinal cross-sectional view taken along the line A--A.

In the figure, 1 is the entire frame made of die-cast alloy, for example, and has a rectangular planar outline, 2 is the flange thereof, and 3, 3a.

3b, 3c, and 3a are mounting portions of magnetic circuit units integrally formed at four locations on the back side of the flange 2 via a plurality of ribs 4, 5, 5A, 5B, and 5C.

5D indicates a magnetic circuit unit fixedly disposed on each mounting portion 3, and 6 indicates a flat composite diaphragm driven by these magnetic circuit units, and this composite diaphragm 6 is made of foamed plastic or other material ( Various skins 6b are attached to both sides of a core 6a made of a honeycomb plate (including a honeycomb plate, etc.).

As is well known, the structure of each magnetic circuit unit 5 includes a U-shaped yoke 7, a magnet 8, a pole 9, a yoke plate 10, a bobbin 11 loosely fitted around the pole 9 and connected to the diaphragm 6, and this bobbin. A movable coil 1 is wound around a bobbin facing into the magnetic gap between the coil 11 and the plate 10.
2, and between the bobbin 11 and each mounting portion 3 is provided a flexible damper 13 made of a suitable material and made of a corrugated disk, for example.

Note that 14 represents an edge member such as rubber or urethane that connects the peripheral portion of the diaphragm 6 and the flange 2, and 15 represents a center cap.

Incidentally, the frame 1 of this type of speaker is made of a die-cast product or a press-molded product, and the flange portion thereof has sufficient strength and is fixed to the cabinet.

On the other hand, since the diaphragm 6 has a narrow aperture ratio on the back side of the frame, the magnetic circuit unit mounting portion 3 is supported by the ribs 4, so its strength must be relatively weak.

Therefore, when driving a speaker after assembly, there is a problem in that the mass of each magnetic circuit unit 5 and the stiffness of each mounting are likely to cause a resonance phenomenon due to the relationship between the mass and the stiffness of each magnetic circuit unit 5, and due to this, the frequency characteristics This causes deterioration of the sound and also has an adverse effect on the sense of hearing.

Incidentally, the vibration mode of resonance is that each magnetic circuit unit 5 vibrates outward of the frame 1 using the base of the outer rib as a fulcrum, as shown by the dashed line 5' in FIG. Maximum at the bottom.

An object of the present invention is to propose a simple and rational means that can effectively avoid resonance as described above.

Note that if only the avoidance of resonance is considered, it may be possible to form a magnetic circuit of an integrated structure instead of separating each magnetic circuit into units.

However, doing so is inappropriate in terms of low frequency reproduction.

In other words, when one diaphragm is driven by multiple magnetic circuits, it is necessary to open the back of the diaphragm to the outside space in order to sufficiently reproduce low frequencies. In order to separate the magnetic circuits as a unit, it is necessary to have a sufficient aperture ratio with respect to the back surface of the diaphragm.

In the present invention, for example, as shown in FIG. 2, a thin disk 16 is used as a reinforcing member at the bottom of each magnetic circuit unit 5.
(see Fig. 3), and insert the magnetic circuit unit 5A through the screw holes 16' drilled at four locations on the periphery of the magnetic circuit unit 5A.
, 5B, 5C, and 5D are all connected by screws to prevent the outward vibrating portion of each unit from causing the above-mentioned resonance.

In this way, each magnetic circuit unit 5 is integrated with respect to the vibration gong, and since each unit regulates the axes of other units, it is possible to avoid the deterioration of frequency characteristics caused by resonance as in the past.

Note that since the force applied to the disk 16 is mainly an expansion/contraction force in the radial direction, its thickness may be quite thin.

FIG. 4 shows a connecting plate 17 as another example of the reinforcing member, which has a cross-shaped shape instead of the circular plate of the previous example.
This is a case where screw holes 17' are provided at both free ends of each crossing piece, but the action and effect that can be achieved by connecting four magnetic circuit units 5 with such a connecting plate 17 is similar to that of a circular plate. 6
It will be easy to understand that it is exactly the same as that of .

The above is a magnetic circuit unit 5.5A as a specific example of the present invention.
, 5B, 5C, and 5D are connected together using reinforcing members made of thin plates.
The connecting point is not necessarily limited to the bottom, but the position and form of the reinforcing member may be such that a connecting plate 18, such as a cross-shaped one, is placed above the bottom, as shown by imaginary lines in FIGS. 1 and 2. , it is also easily conceivable to integrally connect four units.

In any case, according to the present invention, this type of speaker resonance phenomenon can be prevented by extremely simple means, and it goes without saying that the acoustic characteristics of the speaker are significantly improved by suppressing such resonance. As an additional effect, there is no need for any special improvements to the frame structure that would increase costs, and the reinforcing members can be simple pressed sheet metal parts or molded products, so overall production costs are reduced. It is very advantageous in this regard, and excellent practical effects can be obtained.

[Brief explanation of drawings]

FIG. 1 is a linear plan view showing an example of a flat speaker to which the present invention can be applied, FIG. 2 is a longitudinal sectional view taken along line A-A, and FIGS. 3 and 4 show examples of reinforcing members. FIG. 1 is a frame, 2 is a flange, 3 is a magnetic circuit unit mounting part, 4 is a rib, 5 is a magnetic circuit unit, 6 is a composite diaphragm, 7 is a yoke, 10 is a yoke plate, 16, 17
and 18 are reinforcing members.

Claims (1)

[Claims] In a multi-point drive type speaker configured to drive a plurality of points of a diaphragm with a plurality of magnetic circuit units, respectively, the plurality of magnetic circuit units have a sufficient aperture ratio with respect to the back surface of the diaphragm. The magnetic circuit units are fixed to the frame at first mounting portions at a distance from each other so that the magnetic circuit units can be removed, and each magnetic circuit unit is reinforced by a substantially rigid body at a second mounting portion other than the first mounting portion. A multi-point drive type speaker connected to each other by members to suppress resonance when the magnetic circuit unit is driven.