JPH0432872Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a speaker device, particularly to a method for driving a diaphragm of a flat speaker.

Generally, when the diaphragm of a speaker is driven, a higher-order resonance mode is generated on the diaphragm due to split vibration, and the so-called nodes, which are the boundaries where the vibration positions are exactly opposite, vibrate in various ways depending on the mode. It appears in various ways. Therefore, by applying the principle that driving the position corresponding to this node can eliminate the divided vibration, and by attaching a voice coil at that position, we have developed various flat plate diaphragms that can expand the piston vibration frequency range. Drive methods have been proposed in the past.

For example, as one-point drive systems, there are methods such as a method in which a voice coil with a large diameter is arranged for the nodal circle, and a method in which a voice coil with a diameter equivalent to that of a cone-type is arranged, but in the former case, the piston vibration frequency Although it can provide a large area, it has the disadvantage that the aperture ratio on the back of the diaphragm is poor and it is very expensive.In the latter case, the aperture ratio on the back of the diaphragm is good and it is inexpensive, but There are disadvantages such as the piston vibration frequency range becomes small and the third mode cannot be eliminated.

There is also a 4-point drive system that uses 4 voice coils and 4 magnetic circuits at the nodes of the resonance mode that occurs in the diaphragm, but in this case it is possible to eliminate up to the 1-3 and 3-1 modes, and the piston vibration Although the frequency range can be expanded and the aperture ratio on the rear surface of the diaphragm is reasonably good, it has drawbacks such as high cost.

In view of this, this idea was developed especially for the four-dimensional flat diaphragm.
It is an object of the present invention to provide a speaker device that can achieve this at a low cost while maintaining a large piston vibration frequency range and a good aperture ratio of the back surface of a diaphragm using a point drive method.

For example, in order to expand the piston vibration frequency range of a square flat diaphragm, it is important to remove the 1-3 and 3-1 modes (degenerate modes) as a practical speaker device. be. So, first, before getting into the main idea of this idea, let's take a look at 1-3.
The 3-1 mode will be explained with reference to FIGS. 1 to 3.

Figure 1A shows two nodes 2 on the diaphragm 1 in the X-axis direction.
and 3 appear, and in this case, the diaphragm 1 vibrates dividedly with the nodes 2 and 3 as boundaries, for example, the + portions on both sides vibrate upward, and the central portion vibrates downward. If we assume that the normal mode of piston vibration that does not cause split vibration is 1 in the X-axis direction and 1 in the Y-axis direction, then in the case of Fig. 1A, two nodes due to split vibration appear only in the X-axis direction, so The mode at this time is called 1-3 mode. Furthermore, FIG. 1B shows a case where two nodes 4 and 5 appear only in the Y-axis direction on the diaphragm 1, and the mode at this time is called the 3-1 mode. When these two modes are added, the result is as shown in Figure 1C, which can be divided into 1-3,
It's called 3-1 mode. Furthermore, this 1-3, 3-1 mode can be expressed as a degenerate mode as shown in FIG. 1D. In other words, the diaphragm 1 at this time
For example, when a portion of the central portion vibrates downward with the substantially annular node 6 as a boundary, the + portion of the outer circumferential portion exhibits a split vibration in which it vibrates upward.

Next, Fig. 1 shows Y for split vibration in the X-axis direction.
FIG. 2 shows a case where split vibrations of the same phase occur also in the axial direction, but the two are in an anti-phase relationship. That is, in the same figure, Fig. 2 A is in the same 3-1 mode as Fig. 1 A, but Fig. 2 B is in the opposite phase to Fig. 1 B, that is, in a reverse phase relationship with Fig. 2 A. In a certain case of 1-3 mode, two nodes 4 and 5 appear in the Y-axis direction in this case as well, as in the case of FIG. 1B. Then, when both modes at this time are added, a mode as shown in FIG. 2C is obtained, which is also called 1-3, 3-1 mode. Furthermore, this mode is represented as a degenerate mode as shown in FIG. 2D. In other words, the diaphragm 1 at this time is
With the substantially radial node 7 as a boundary, for example, when the upper and lower portions vibrate downward, the left and right + portions exhibit a divided vibration in which they vibrate upward.

The common points in each degenerate mode in FIGS. 1 and 2 are points 8, 9, 10 and 11 where nodes 6 and 7 intersect, as shown in FIG. In other words, points 8 to 10 are common nodes for the two degenerate modes, 1-3 and 3-1 modes. Therefore, in the four-point drive system, by driving these four points (nodes), the 1-3 and 3-1 modes can be removed and the piston vibration frequency range can be expanded.

Next, an embodiment in which this invention is applied to such a four-point drive system will be described in detail with reference to FIGS. 4 to 6.

FIG. 4 shows an example of the structure of the support body 20, which is the main part of this invention. In the figure, 21 is a plurality of hollow bodies provided corresponding to the number of points to be driven. For example, they are cylindrical supporting members forming the same, and since the four-point drive system is used here, four similar ones are provided. Reference numeral 22 denotes, for example, an annular base to which the support member 21 is attached, and this base 22 consists of a cylindrical portion 22 _a and wing portions 22 _b extending radially from the cylindrical portion 22 _a . 2
_2b , one end side of each support member 21 is fixed at approximately equal intervals corresponding to the driving points of the diaphragm. Therefore, the support member 21 extends radially obliquely upward from the wing portion _22b . Note that the diaphragm 1 is coupled to the frame via an edge (not shown).

Reference numeral 23 denotes a plurality of connecting members (four in this case) fixed to the other end of each supporting member 21, and the connecting members 23 allow the supporting body 20 to be connected as shown in FIG. It is connected to the diaphragm 1.

FIG. 5 shows a state in which the support body 20 as described above is attached to the diaphragm 1. The _diaphragm 1 consists of a core member 1 _a of honeycomb structure or foam-filled type, and skin layers 1 _b and 1 _c disposed on the upper and lower surfaces of the core member 1 a, respectively. A plurality of slits 24, in this case four slits 24, are provided at positions corresponding to each drive point of the diaphragm 1, the slits 24 being large enough to fit the connecting members 23 of the support body 20. When installing, each connecting member 23 corresponding to each of these slits 24 is fitted, and after bending the tip portion of the connecting member 23 that protrudes toward the skin layer 1 _b side, this portion is attached to the skin layer 1 with adhesive or the like. It sticks to _{the b} side. Further, the portions of the connecting member 23 and the supporting member 21 that come into contact with the skin layer _1c side are also fixed with adhesive or the like. Incidentally, before inserting the connecting member 23, adhesive may be poured into the slit 24 and then the above-described fixing method may be used.
Further, the skin layer 1 _c of the support member 21 which is a hollow body
It is preferable that the diameter of the portion that comes into contact with the opening, that is, the opening, is larger. This is because if the support member 21 is a hollow body and the diameter of the opening thereof is large, the force per unit area applied to the skin layer 1 _c is reduced, and the distortion of the diaphragm can be reduced.

FIG. 6 shows the assembly structure of the support body 20 and the cylindrical voice coil bobbin 25, etc. In the same figure, the voice coil 26 with a predetermined number of turns is mounted on the bobbin 25.
is wound, and the upper end side of this bobbin 25 is attached to the base 22.
It is fitted into the cylindrical part _22a of the cylindrical part 22a and fixed with adhesive or the like. Further, the bobbin 25 is coupled to the frame via a damper (not shown).

Further, 27 is a center pole, 28 is a pole piece, 29 is a magnet, 30 is a yoke, and 31 is a gap formed by these parts. 27 to 31 form a magnetic circuit, and the back side of the frame will be distributed. This magnetic circuit causes the coil 26 of the bobbin 25 to be loosely fitted into the air gap 31.
A driving magnetic flux is applied to the

As described above, according to this invention, the diaphragm and at least the voice coil bobbin are connected by a support having a hollow support member, so that the following various effects can be obtained. can.

1 Even in the case of multiple point drive systems such as 4-point drive, the voice coil bobbin, coil, and magnetic circuit each have one
Since only one piece is required, the configuration becomes simple and the material cost can be significantly reduced, and the number of man-hours required for manufacturing voice coil wiring etc. is also reduced, making it possible to save labor.

2. Since the aperture ratio on the back surface of the diaphragm can be increased, the difference in acoustic impedance when the diaphragm moves back and forth is reduced, and it is also advantageous for the heat dissipation effect of the voice coil.

3 Since the diameter of the diaphragm drive section can be substantially larger than the diameter of the voice coil bobbin, the aperture ratio on the back of the diaphragm can be increased, and conversely, the voice coil bobbin and magnetic circuit can be made smaller in shape, resulting in lower costs. can contribute to

4. By using a hollow supporting member, the weight of the supporting member can be reduced without reducing the load per unit area of the portion where the skin layer and the supporting member are in contact.

5 By using a connecting member connected to the support member, it is possible to compensate for the decrease in the adhesion force at the opening of the support member, and if only the adhesion agent at the opening of the support member is used, only the bottom side of the diaphragm is pulled. This creates a gap and causes so-called compliance (capacitance component), resulting in deterioration of sound quality. However, in this invention, the connecting member simultaneously pulls the skin layer, core member, and skin layer in a sandwich shape, so the above-mentioned deterioration of sound quality is avoided. It is never accompanied by

6 By bending the tip of the connecting member,
There is no need to wait until the adhesive dries, which simplifies the bonding process.

In addition, in the above-mentioned embodiment, the case where the support member 21 is connected to the voice coil bobbin 25 via the base 22 has been described, but the base 22 and the bobbin 25 are connected to each other.
Alternatively, the support member 21 may be directly connected to the bobbin 25 side.

In addition, in the above-mentioned embodiment, this invention has been explained in the case of a four-point drive system, but it is not limited to this, and can also be applied to other drive systems by considering the number of supporting members, etc. It is possible that the same applies.

Further, the shape of the support body may be changed according to the shape of the diaphragm without departing from the gist of the present invention.

[Brief explanation of the drawing]

1 to 3 are diagrams for explaining the 1-3 and 3-1 modes, FIG. 4 is a perspective view showing the support body 20 according to this invention, and FIGS. 5 and 6 are diagrams showing this support body 20. FIG. 2 is a sectional view showing an embodiment of the invention. 1 is a diaphragm, 20 is a support body, 21 is a support member,
22 is a base, 23 is a connecting member, 25 is a voice coil bobbin, 26 is a voice coil, 27 is a center pole, 28 is a pole piece, 29 is a magnet, 30 is a yoke, and 31 is a gap.

Claims (1)

[Scope of utility model registration request] A plurality of hollow supporting members 21 each having one end fixed to a plurality of driving points of the diaphragm 1 and a single voice coil bobbin 25 disposed at the other end are used to connect the diaphragm and the above. A speaker device characterized by integrally connecting a voice coil bobbin.