JPS6239598B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a speaker suitable for use as an electroacoustic transducer for various types of audio equipment, and in particular is capable of reproducing good audio signals without mechanical distortion.

Conventionally, a speaker as shown in FIG. 1 has been proposed.

That is, in this FIG. 1, 1 is a permanent magnet, 2
is a pole piece, 3 is a pole yoke, 4 is a voice coil bobbin, 5 is a voice coil, 6 is a diaphragm (cone), 7 is a dust cap, 8 is a frame,
9 is a diaphragm; 6 is a damper provided to properly hold the diaphragm 1 relative to the permanent magnet 1 and prevent it from tilting against axial movement; A roll-shaped edge made of paper or the like to be formed is shown, and reference numeral 11 is a stopper for fixing this edge 10 to the frame 8.

Since the conventional speaker is constructed as shown in FIG.
The radius from the central axis O (not shown) of the vibration system 0 changes each time depending on the vibration of the diaphragm 6. That is, as shown in FIG. 2A, when the diaphragm 6 is not displaced at all, focusing on the neutral position P of the edge 10 whose distance from the central axis O is R, as shown in FIG. 2B , for a positive displacement of the diaphragm 6 in the direction away from the frame 8, the neutral position P of the edge 10 is at a distance R+ from the central axis O.
△r ₁ , so the circumference of a concentric circle centered on the central axis O that includes the neutral position P of this edge 10 is 2πR
to 2π(R+△r ₁ ), and as shown in FIG. Since the distance from the edge 10 is R-△r ₂ , the circumference of a concentric circle centered on the central axis O that includes the neutral position P of this edge 10 is 2πR to 2π(R-△r ₂ )
decreases to

In this way, the edge 10 receives a tensile stress in the circumferential direction when the diaphragm 6 makes a positive displacement, and conversely receives a compressive stress in the circumferential direction when the diaphragm 6 makes a negative displacement. will receive.

By the way, it is well known that when a roll-shaped edge with a semicircular cross section is constructed into an annular shape, such as the speaker edge 10 shown in FIG. 1, strictly speaking, it becomes a rigid body unless the material has elasticity. .

Therefore, the edge 10 of the speaker as shown in FIG. 1 expands and contracts in response to the tensile stress and compressive stress applied to the edge 10 solely due to the elasticity of the edge material constituting the edge 10. This means that

Therefore, edge materials such as paper used for the edge 10 of a speaker as shown in FIG. 1 often buckle when subjected to compressive stress, as well as under tensile stress. As the edge 10 cannot absorb internal stress sufficiently, there is a high possibility that the vibration state of the edge 10 will cause a rolling mode that has an adverse effect on audio reproduction.

As mentioned above, according to the speaker as shown in FIG. The audio signal reproduced by this speaker when the displacement of the diaphragm 6 is large,
In particular, there was a risk of adverse effects such as mechanical distortion occurring on low-frequency audio signals near the reduced resonance frequency f _p of this speaker.

In view of these points, the present invention proposes a speaker capable of reproducing a good audio signal without the above-mentioned mechanical distortion.

Hereinafter, one embodiment of the speaker of the present invention will be described with reference to FIG. In FIG. 3, parts corresponding to those in FIG. 1 are designated by the same reference numerals, and detailed explanation thereof will be omitted.

That is, in this FIG. 3, the edge 12 has a diamond pattern (so-called Yoshimura pattern) structure composed of a combination of small triangles, as shown in FIG. 4A, which is an enlarged perspective view of a part of this edge 12. is annular and arranged around the outer periphery of the diaphragm 6. In this case, paper or the like is used as the edge material, and when a part of the edge 12 shown in FIG. 4A is developed, a developed view as shown in FIG. 4B is obtained; If the broken line portion 13a and the solid line portion 13b in the radial direction are bent alternately, the structure shown in FIG. 4A can be obtained.

When the edge 12 configured in this way is bent by applying force in the _x1 direction as shown in Fig. 4A, the intersection angle between the two planes defined by the adjacent triangles becomes smaller. When the direction changes and shrinks in the y ₁ direction, and conversely, a force is applied in the x ₂ direction and bends, 2 is determined by the adjacent triangles in parallel with this.
The intersection angle of the two planes changes in the direction of increasing
y Extends in _two directions.

Therefore, in the speaker shown in FIG. 3, when the diaphragm 6 is not displaced at all as shown in FIG. 5A, the distance from the central axis O of the vibration system is R.
Focusing on the neutral position Q of the edge 12, as shown in FIG.
The distance of the neutral position Q of 2 from the central axis O is R + △r ₁
At the same time, this edge 12 is bent by applying a force in the x ₂ direction as shown in FIG. Since the circumference of the concentric circles centered on O increases from 2πR to 2π(R+Δr ₁ ), no internal stress (tensile stress) is applied to the edge material itself constituting the edge 12. Similarly, for a negative displacement of the diaphragm 6 in the direction toward the frame 8 as shown in FIG _. At the same time, Edge 12 has a fourth
Since the edge 12 is bent by applying a force in the x ₁ direction as shown in Figure A, due to the necessity of the shape of the edge 12,
The circumference of a concentric circle centered on the central axis O that includes the neutral position Q of this edge 12 is 2π(R−△
r ₂ ), no internal stress (compressive stress) is applied to the edge material itself constituting the edge 12.

As described above, in the speaker of the present invention, the edge 12 expands and contracts in the circumferential direction in conjunction with the displacement of the diaphragm 6. Since no internal stress is applied at all, the edge material such as paper forming the edge 12 is completely free from nonlinearity such as buckling. Furthermore, no internal stress is applied to the edge material itself constituting the edge 12, and the edge 12 is in the rolling mode in the direction in which the triangular component is twisted (a large force is required). It is expected that there is little possibility that a rolling mode will occur in the vibration state of the edge 12.

Therefore, when the displacement of the diaphragm 6 is relatively large, the speaker of the present invention can obtain a good reproduced signal without mechanical distortion even for a reduced audio signal near the reduced resonance frequency f _p of this speaker. be able to.

In the case of the above-described embodiment, the triangles of the diamond pattern structure constituting the edges 12 are constructed so that all sides in the radial direction are equal in length, but as shown in the developed view of FIG. 6A, The length of the sides in the radial direction of the triangle may be sequentially changed. In this case, the curvature of the cross section of the edge 12 becomes large, so naturally, when there is no displacement of the diaphragm 6, the bonded end with the diaphragm 6 and the bonded end with the frame 8 are connected as shown in FIG. 6B. This results in speakers having different heights.

Further, in the case of the above-mentioned embodiment, the diamond pattern structure shown in FIG. 4A is used only for the edge 12, but as shown in FIG.
3 has a diamond pattern structure as shown in FIG. 4A, the damper 13 expands and contracts in the circumferential direction in conjunction with the displacement of the diaphragm 6. Since no internal stress is applied to the edge 12, it is suitable like the edge 12.

Further, the present invention is not limited to the above-described embodiments, and it goes without saying that various other configurations may be adopted without departing from the gist of the present invention.

[Brief explanation of the drawing]

FIG. 1 is an enlarged sectional view showing an example of a conventional speaker, FIG. 2 is a line diagram for explaining FIG. 1, FIG. 3 is a sectional view showing an embodiment of the speaker of the present invention, and FIG.
Figures A and B are an enlarged perspective view and a developed view of a portion of the speaker of the present invention shown in Figure 3 and a developed view, respectively.
The figures are diagrams for explaining the present invention, Figures 6A and B.
is a developed view of a part of the edge showing another embodiment of the edge of the speaker according to the present invention, and a line diagram for explaining the edge;
FIG. 7 is a sectional view showing another embodiment of the speaker of the present invention. 6 is a diaphragm, 8 is a frame, 12 is an edge, 1
3 is a damper.

Claims (1)

[Claims] 1. A roll-shaped edge provided on the outer periphery of the diaphragm has a diamond pattern structure composed of a combination of small triangles, and expansion and contraction of the edge in the circumferential direction due to displacement of the diaphragm is performed in conjunction with displacement of the diaphragm. A speaker characterized by being able to