JPS5943875B2 - electrodynamic speaker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrodynamic speaker, which has sufficiently high compliance in the axial direction of a voice coil, and
To provide an electrodynamic speaker equipped with a damper that has good linearity even with large amplitudes and has a sufficient regulating force against forces in a direction perpendicular to the axis of a voice coil.

FIG. 1 shows a conventional electrodynamic speaker.

1 is a yoke in which the center pole 2 is integrally formed; 3 is a through hole passing through the center pole 2 and the yoke 1; 4 is a through hole that passes through the center pole 2 and the yoke 1;
is an annular magnet fixed to the upper surface of the yoke 1, and 5 is an annular plate fixed to the upper surface of the magnet 4. An annular magnetic field is formed between the inner circumferential surface of the plate 5 and the outer circumferential surface of the center pole 2. A gap is formed.

6 is a frame fixed to the plate 5; 7 is a diaphragm; the outer periphery of the diaphragm 7 is supported by the frame 6 via an edge member 8;

A coil bobbin 9 is fixed to the center of the diaphragm 7, and a voice coil 10 is wound around the coil bobbin 9.

This voice coil 10 is located at the differential magnetic gap portion.

11 is a dust camp; 12 is a damper whose inner circumferential part is fixed to the outer circumferential surface of the coil bobbin 9 and whose outer circumferential part is fixed to the frame 6; as shown in FIG. It is made by heating and molding into a corrugated shape.

The requirements for the damper 12 of this type of electrodynamic speaker are: A. Sufficiently high compliance in the axial direction of the voice coil and good linearity even at large amplitudes, B. Sufficient compliance in the axial direction of the voice coil, and B. For example, it must have sufficient stiffness.

In the damper 12 of the conventional electrodynamic speaker,
In order to satisfy condition B above, the spring constant in the radial direction of the damper 12 is made sufficiently high, so condition A above is not satisfied, and especially when the amplitude is large, as shown by a in FIG. 3, There is a drawback that a nonlinear portion occurs in the Kerr displacement characteristic.

In other words, bending stress and tensile stress act on the material of conventional wave dampers, and as the displacement of the coil bobbin increases, the tamper itself stretches, but since the elongation rate with respect to the displacement of the damper is nonlinear, the Kerr displacement characteristics are nonlinear. It is something that occurs in parts.

Conventional speakers using such dampers have the disadvantage that their low frequency characteristics include a large amount of harmonic distortion.

The present invention eliminates the above-mentioned conventional drawbacks, and one embodiment of the present invention will be described below with reference to the drawings.

FIG. 4 is a top view of a damper according to an embodiment of the present invention,
This damper is a circular plate made of cloth impregnated with phenolic resin or the like, with slits and circumferential bends formed therein.

The structure of the damper of this embodiment will be explained below.

In FIG. 4, 13 is a hole formed in the center of a disc 14, and a coil bobbin is inserted into this hole 13 and fixed.

The outer periphery of the ring portion 15 at the edge of the hole 13 is divided into six sections by slits 16 formed in the radial direction, and six damper pieces 17a to 17f are formed.

A common ring portion 18 is formed on the outer periphery of these six damper pieces 17a to 17f.

The structures of the damper pieces 17a to 17f are completely the same, and the structure of the damper piece 17a will be described below.

19 is a circular bent portion formed on the outer periphery of the ring portion 15 on the inner peripheral side; 20 is a slit formed in the radial direction in the center of the slits 16 on both sides dividing the damper piece 17a; and 21 is the slit formed in the radial direction. It is a circular bent part with a larger diameter than the circular bent part 19, and between the bent parts 19 and 21 of the damper piece 17a is a common piece 22, 2 divided by a slit 20.
3 is formed.

24 is a slit formed in a radial direction from the center of the outer circumference of the common piece 22, and 25 is a slit formed in a radial direction from the center of the outer circumference of the common piece 23.

A long surface element 26 is formed between the slit 24 and the slit 16.

A bent portion 27 is formed at the boundary between the long surface element 26 and the ring portion 18 on the outer periphery.

Moreover, between the slit 25 and the slit 16, there is a long surface element 2'.
8 is formed, and this long surface element 28 and the ring part 18 on the outer periphery
A bent portion 29 on the same circumference as the bent portion 27 is formed at the boundary.

Further, between the slits 24 and 25, a circular arc-shaped bent portion 30.31 with different diameters is formed, and is divided into three parts. The section is divided by the slit 20 and constitutes divided plane elements 32 and 33, and the second section between the bent parts 30 and 31 is a central plane element 34.
A fixed surface element 35 integral with the ring part 18 is formed in the third section of the outer peripheral part of the bent part 31.

FIG. 5 shows only the damper piece 17a of FIG. 4.

Figure 6 a, b, c, d are O in Figure 4 or Figure 5.
A, OB, QC, and OD cross sections are shown, and the common piece 22 and the long surface element 26 form an upwardly convex mountain shape, and the common piece 22 and the divided surface element 33 form an upwardly convex mountain shape, and the common piece 22 and the long surface element 26 form an upwardly convex mountain shape. The piece 23 and the divided surface element 32 form a downwardly convex mountain shape, and the common piece 23 and the long surface element 2
8 is bent at each bending part so as to form a downwardly convex mountain shape.

Damper pieces 17b to 17 similar to the above damper piece 17a
f is formed on the outer periphery of the ring portion 15 to constitute a damper.

FIG. 7 shows the main parts of an electrodynamic speaker equipped with the damper, in which a ring part 15 is fixed to the outer circumference of the coil bobbin 9, and a ring part 18 on the outer circumference is attached to the annular fixing base 3.
It is fixed at 6.

As shown in FIG. 8, this fixing base 36 is formed with a plurality of protrusions 37 that protrude inward.

This protrusion 37 has the same shape as the fixed surface element 35 integrally formed on the ring part 18 of the damper, and
5 is fixed to the upper surface of the protrusion 37.

Reference numeral 38 denotes a protrusion that is integrally formed on the outer periphery of the upper surface of the fixing base 36.

Note that when the coil bobbin 9 is in a stationary state, the ring portion 15, the ring portion 18, and the fixed surface element 35 are located on the same horizontal plane perpendicular to the central axis of the coil bobbin 9.

Next, the operation of the damper will be explained.

The relationship between the lengths of each month and each plane element in FIG. 6 is as follows.

B1C1=B2C2=C3D3=C4D4-A2B2=
3D3 E1B1=E4D4 E2F2=F2A2=E3F3=F3A3 FIG. 9 shows a projection of each cross-sectional shape in FIG. 6 onto one plane.

In FIG. 9, the solid line shows the state when the voice coil is at rest, and the broken line shows the state when the voice coil is displaced.

In Figure 9, ABCD is an equilateral parallelogram,
The arc REtRF has a radius E1 with centers E and F, respectively.
D-E4D4=γ.

and F2A2=F3A3-rF, which is a trajectory that can pass through points B(D) and A.

Now, when the voice coil is displaced and the 0 point moves to the 07 point, as shown by the broken line, the equilateral parallelogram becomes A'B'C'.

Let P' be the intersection of straight lines EC' and B'D'. However, B'
, D is radius B1C1=C2B2=Cs with center as C'
D s ”” C4B4 ”” 7 C7 arc R
This is the intersection of cl and the arc RE.

Further, the triangles E B'P' and B'yσ are right triangles.

The following relational expression holds true for this right triangle EB'P' and B/p/c/.

EB72 gP"'=f3'P"'=B'c"'
C/P/2... (1) From (1) □□□□ EP/2 C'P"'=EB"' B/c/2
・・・・・・(2) Right side of equation (2) EB / 2 B
/c/2 is a constant value since EB' and B'C' are the long surface element 26 and the common element 22, respectively.

Therefore, EP/2-C/p/2 in equation (2) shows a constant value.

In particular, the left side of equation (2) is EP"-C'P"'= (EP'
+C'P') (EP'-C'P')= EC'X E
A: It can be broken down into (3).

In other words, EC'XEA' is a constant value, and similarly for the equilateral parallelogram ABCD shown by the solid line in the stationary state, ECXEA=EB2-BC2=EB"-B'C"'
(4) is proven.

Therefore, EC'X EA'= ECX EA...
・・・・・・・・・・・・・・・(5)

Regarding triangles EC'C and FAA', from equation (5), 2
”:EA=EC: Since W and 1AEA' are common, triangles EC'C and FAA' form similar shapes.

Therefore, since /EA'A is a right angle, it is proven that /C'CF is a right angle.

That is, the base C' of the coil bobbin always moves on a straight line perpendicular to AC.

This means that the voice coil always reciprocates in a straight line.

The maximum displacement of linear reciprocating motion occurs when the four sides of an equal-sided parallelogram overlap and form a straight line.

As described above, in this embodiment, the expansion of the damper due to the increase in displacement of the coil bobbin can be realized by the bending mechanism between each month and each surface element, so that sound pressure harmonic distortion can be eliminated.

In other words, a conventional wave-shaped damper must expand in the circumferential direction and radial direction as the displacement of the coil bobbin increases, and this expansion has non-linearity with respect to each displacement, and the expansion with respect to vertical displacement. Because the ratios are different, support system distortion occurs, and sound pressure harmonic distortion occurs as a speaker.
According to this embodiment, since each piece and each surface element itself does not need to extend in response to displacement, sound pressure harmonic distortion can be reduced.

FIG. 3b shows the Kerr displacement characteristics of the damper of this example.

Note that the stiffness required for the damper in the above embodiment is determined by the restoring force of the bending portion between each month and each surface element.

Although the bends between each month and each surface element in the above embodiment are circular arcs, they may be straight bends.

FIG. 10 shows another embodiment of the invention.

In this embodiment, V-shaped ribs 39 and 40 are respectively formed in the center of the common pieces 22 and 23 of the embodiment shown in FIG. 4, and these ribs 39 and 40 absorb the force in the circumferential direction of the damper. In addition, reinforcing ribs are provided on each month and each surface element to increase the bending rigidity of each month and each surface element.

FIG. 11 shows a main part of an electrodynamic speaker equipped with the damper shown in FIG. 10.

Although the reinforcing ribs in the above embodiment are bent so that the center of each month and each surface element is upward, it may also be shaped such that the center of each month and each surface element protrudes downward. be.

FIG. 12 shows a damper according to still another embodiment of the present invention.

In this embodiment, four damper pieces 42aj42b are provided on the outer periphery of a square central support portion 41 in which a hole 13 into which a coil bobbin is inserted is formed.

42C and 42d. In the above embodiment, each month and each plane element are fan-shaped, whereas in this embodiment, each month and each plane element are square in shape, and a reinforcing rib is provided in the center. It is something that

In FIG. 12, parts having the same functions as those in the embodiment shown in FIG. 4 are given the same numbers.

The present invention has the above-described configuration, and has the advantage that distortion in the support system of the coil bobbin can be reduced, and sound pressure harmonic distortion as a speaker can be reduced.

[Brief explanation of the drawing]

Figure 1 is a sectional view of a conventional electrodynamic speaker, Figure 2 is a half sectional view of a damper of a electrodynamic speaker, and Figure 3 is a half sectional view of a damper of a conventional electrodynamic speaker. 4 is a top view of a damper of an electrodynamic speaker according to an embodiment of the present invention, FIG. 5 is an enlarged top view of a part of the damper, and FIGS. Figure 4 is a sectional view of each part, Figure 7 is a perspective view of the main parts of an electrodynamic speaker using the same damper, Figure 8 is a top view of the fixing base of the electrodynamic speaker, and Figure 9 is an electrodynamic speaker. Diagram for explaining the operation of electric type speakers, No. 10
The figure is a top view of a damper according to another embodiment of the present invention, and FIG. 11 is a perspective view of the main parts of an electrodynamic speaker using the same damper.
FIG. 12 is a top view of a damper according to still another embodiment of the present invention. 1...Yoke, 2...Center pole, 3...Surface hole, 4...Magnet, 5...
...Plate, 6...Frame, 7...
...Diaphragm, 8...Edge member, 9...
...Coil bobbin, 10...Voice coil, 1
1... Dust cap, 13... Hole,
14...Disk, 15...Ring part, 1
6...Slit, 17a-17f...
Damper piece, 18...Ring part, 19...
...Bending part, 20...Slit, 21...
...Folded part, 22.23...Common piece, 24...
...Slit, 25...Slit, 26.
...Long side piece, 27...Bent part, 28...
・・・・Long side element, 29 ・・・・Bending part, 30.31
...Bending part, 32, 33...Divided surface element, 34...Central surface element, 35...Fixed surface element, 36... ...Fixing base, 37...Protrusion, 38...Protrusion, 39°40...Rib, 41...Central support part, 42a-42d ...
...damper piece.

Claims (1)

[Claims] 1. A plurality of damper pieces are provided radially through bent parts on the outer circumference of the central support part into which the coil bobbin is inserted and fixed, and a common ring part is formed on the outer circumference of each of the damper pieces, and the damper A first and second common piece divided by a first slit is provided on the side of the central support portion of the piece, a bent portion is provided on the outer periphery of each of the first and second common pieces, and the above-mentioned Second and third slits extending from the outer periphery of each of the first and second common pieces to the ring part are formed between a part of the outer periphery of the first and second common pieces and the ring part. A first and second long surface element is formed, a bent part is formed at the boundary between the first and second long surface element and the ring part, and a bent part is formed between the second slit and the third slit. The part in between is divided into three parts by two bent parts extending from the common side to the ring part, and among these three divisions, the first part on the common side is divided by the first slit to form a first, A second divided surface element is formed, the section on the ring part side of the three sections is made into a fixed surface element integral with the ring section, and the length of the central section of the three sections and the length of the fixed section are The length of the common piece and the length of the 10-base division plane element are the same, and the length of the above-mentioned first
A bent surface formed by a common piece, a long surface element connected to this first common piece, and a divided surface element is made to protrude upward, and a bent surface formed by a common piece connected to the second common piece The bent surface formed by the long surface element and the divided surface element is made to protrude downward,
The attachment part of the central support part to the coil bobbin, the ring part, and the fixed surface element provided integrally with the ring part are fixed to the fixation part, and the attachment part of the central support part to the coil bobbin and the ring part are fixed to the fixation part. An electrodynamic speaker comprising a damper in which the fixed surface element is located on the same plane perpendicular to the central axis of the coil bobbin.