JPH11168793A - Electroacoustic transducer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electroacoustic transducer which is capable of reducing the generation of distortion due to higher harmonics, of suppressing the changes in stiffness of an edge part and moreover of allowing large stroke of a diaphragm. SOLUTION: Roll shapes vertically symmetrical to a vibration surface are alternately formed with equal intervals in a circumferential direction and an edge is provided for connecting respective vertically symmetrical roll parts by a plane 18 which is formed at a certain angle α of a certain range formed by a vibration surface 14 and a tangent (a) drawn in the inner circumferential part of the roll shape along an almost tangential direction 12 of a curve 11 for forming an inner circumference.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electro-acoustic transducer such as a speaker or a microphone.

[0002]

2. Description of the Related Art A loudspeaker has a diaphragm, and the outer periphery of the diaphragm is supported via an edge. The edge is also required to have various characteristics such as shape and material in order to obtain desired acoustic characteristics. ing. Thus, there are various types of speakers, of which FIG. 9 is a longitudinal sectional view of a conventional speaker provided with an up-roll type edge portion, and FIG. It is explanatory drawing which shows the difference of the air amount which the edge part of an up roll type removes when moving in the front-back direction.

The loudspeaker shown in FIG. 9 has a yoke 2 constituting a bottom portion 1 of the loudspeaker, a magnet 3 mounted on an upper surface of the yoke 2, a pole piece 4 mounted on an upper surface of the magnet 3, and A voice coil 5 and a voice coil bobbin 6 held in a magnetic gap between the yoke 2 and the pole piece 4, a dome-shaped diaphragm 7 fixed to the tip of the voice coil bobbin 6, and an outer peripheral portion of the diaphragm 7 It is provided with an up-roll type edge portion 8 provided and a frame 9 for holding each of the above members.

[0004]

In the loudspeaker, the outer periphery of the diaphragm 7 is supported by an edge 8 so as to be able to vibrate. The linearity of the supporting portion of the diaphragm 7 with respect to the input becomes vertically asymmetrical as the amplitude increases, which causes harmonic distortion. For example, in the case of an up-roll type edge portion, as shown in FIG. 10, even when the diaphragm 7 moves forward and backward by the same amount of displacement, the air amounts A1 and A2 removed by the edge portion 8 are different. Becomes Further, as the amount of displacement of the diaphragm 7 increases, the difference increases.

The sound pressure of the loudspeaker is proportional to the sum of the amount of air removed by the diaphragm 7 and the edge 8. For this reason, the sound pressure difference before and after increases as the amplitude of the diaphragm 7 increases,
As a result, there is a problem that harmonic distortion increases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to reduce the occurrence of harmonic distortion, to reduce the occurrence of a change in stiffness at the edge portion, and to further reduce the vibration of the diaphragm. An object of the present invention is to provide an electroacoustic transducer having an edge capable of taking a large stroke.

[0007]

In order to achieve the above object, according to the present invention, a roll shape which is vertically symmetrical with respect to a vibrating surface 14 is alternately formed at equal intervals in a circumferential direction 13 and a curved line which forms an inner circumference. A tangent line a drawn on the inner periphery of the roll shape along a substantially tangential direction 12 of
And an edge connecting each of the vertically symmetric roll portions by a plane 18 formed at an angle α within a certain range.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 5 show a first embodiment of the present invention. FIG. 1 is a plan view of a diaphragm and an edge portion supporting the diaphragm, and FIG. 2 is a sectional view taken along the line AA 'of FIG. , And FIG.
FIG. 4 is an enlarged explanatory view showing the plane shape and the cross-sectional shape of the roll adjacent to the edge portion in the circumferential direction, and cross sections corresponding to the plane are taken as CC ′ to HH ′. I'm drawing. FIG. 5 is a sectional view of a speaker supporting a diaphragm at the edge portion.

In the first embodiment of the present invention shown in these figures, as shown in FIGS. 1 and 2, the edge 10 supporting the diaphragm 7 is substantially tangential to the inner circumference 11 of the edge 10. A plurality of rolls 15 are formed along the line 12 and at equal intervals in the circumferential direction 13 of the edge portion.

As shown in FIGS. 3 and 4, the roll 15 is formed by assembling upper and lower rolls 16 and 17 in a vertically symmetric manner. And the roll 15 adjacent to the circumferential direction 13 of the edge part 10 is
The upper roll 16 and the lower roll 17 are alternately arranged. In this embodiment, the up roll 16 and the down roll 17 of each roll 15 are formed at an angle α ° 70 ° between the vibrating surface 14 of the edge portion 10 and the angle α 振動 70 °.
Are connected by a plane 18. In the present invention, the plane 18 that contacts the upper and lower roll portions is formed substantially in the tangential direction 12 of the curve 11 that forms the inner periphery of the roll 15.

The angle α is, as shown in FIG.
It corresponds to the angle between the vibrating surface 14 and a tangent a drawn on the inner peripheral portion of the roll 15.

The diaphragm 7 is supported by the frame 9 through the edge 10 configured as described above, as shown in FIG. In FIG. 5, the same members as those in FIG. 9 showing the related art are denoted by the same reference numerals.

According to the first embodiment, the up rolls 16 and the down rolls 17 of the rolls 15 adjacent to each other in the circumferential direction 13 of the edge portion 10 are alternately formed. The sum of the amount of air removed from the portion of the roll 15 adjacent to the roller 13 is equal between the case where the edge portion 10 moves forward and the case where the edge portion moves backward. As a result, the amount of air removed from the edge portion 10 also increases. Is equivalent to the case of moving backward. Thereby, the diaphragm 7 and the edge portion 1
The amount of air eliminated by 0 is equal between the case where the air moves forward and the case where it moves backward, and therefore, the occurrence of harmonic distortion can be reduced.

Further, in comparison with the conventional example in which the vertically symmetrical rolls are simply arranged alternately in the circumferential direction of the edge portion, this first roll-up roll is provided.
In the embodiment, since the portion (the flat surface 18) connecting the up roll 16 and the down roll 17 is formed substantially in the tangent direction of the tangent a of the curve 11 forming the inner circumference of the roll 15, the curvature of the roll shape is changed. Without the edge 1
Because it has little effect on zero compliance
It is possible to make the stiffness of the edge portion 10 hardly change.

Furthermore, unlike the conventional so-called tangential edge, the edge portion 10 has a roll shape as a basis, and therefore has an advantage that a large stroke of the edge portion 10 can be taken.

FIGS. 6 to 8 show a second embodiment of the present invention. FIG. 6 is a plan view of a diaphragm and an edge portion for supporting the diaphragm, and FIG. 7 is a line II 'in FIG. FIG. 8 is a sectional view, and FIG.
It is -J 'sectional drawing.

In the second embodiment shown in these figures, as can be seen from FIGS. 7 and 8, the up roll 16 and the down roll 17 of each roll 15 formed on the edge portion 10 cause the vibration of the edge portion 10 to move. Angle α ≒ 90 ° with surface 14
Are connected by a plane 18.

That is, the tangent to the inner peripheral portion of the roll and the vibrating surface 1
4 changes depending on the radius R and the height h of the roll 15, and when R = h, the angle α is 90 °.

If h is smaller than R, it becomes 70 ° or less as in the above-described embodiment. The range of the angle α is about 90 ° to 45 °.

Also in the second embodiment, since the curvature of the roll shape is not changed and the compliance of the edge portion 10 is hardly affected, the edge portion 1
It is possible to make it hard to cause a partial stiffness change of 0.

The other structure of the second embodiment is the same as that of the first embodiment, and the operation is also the same.

[0023]

As described above, in the present invention, the inner periphery 11 of the edge portion 10 supporting the diaphragm 7 is substantially tangential to the inner periphery 11 and is equally spaced in the circumferential direction 13 of the edge portion 10. To form a roll 15 in which an up roll 16 and a down roll 17 are combined in a vertically symmetrical manner,
Up roll 1 of roll 15 adjacent in circumferential direction 13 of 0
6 and the down roll 17 are formed alternately, so that the sum of the amount of air removed from the roll 15 adjacent to the edge 10 in the circumferential direction 13 is equal to the case where the edge 10 moves forward and backward. And the edge part 1
Since the amount of air removed from zero is equivalent when the air moves forward and backward, the amount of air eliminated by the diaphragm 7 and the edge portion 10 becomes equal when the air moves forward and backward, and therefore, the harmonics are reduced. This has the effect of reducing the occurrence of wave distortion.

Further, according to the present invention, the up roll 16 and the down roll 17 forming the roll 15 are formed at an angle α between a tangent drawn on the inner peripheral portion of the roll shape and the vibrating surface 14. Since the connection is made by the flat surface 18, the curvature of the roll shape is not changed, and the edge portion 10 is not changed.
Has little effect on the compliance of the edge portion 10, so that the stiffness of the edge portion 10 can be hardly changed.

Moreover, in the present invention, since the edge portion 10 is basically in the form of a roll, there is an advantage that the stroke of the edge portion 10 can be made larger than that of a conventional tangential edge.

[Brief description of the drawings]

FIG. 1, showing a first embodiment of the present invention, is a plan view of a diaphragm and an edge portion supporting the diaphragm.

FIG. 2 is a sectional view taken along line AA ′ of FIG.

FIG. 3 is a sectional view taken along line BB ′ of FIG. 1;

FIG. 4 is an enlarged explanatory view showing a planar shape and a cross-sectional shape of a roll adjacent to an edge portion in a circumferential direction in the first embodiment.

FIG. 5 is a sectional view of the speaker in the first embodiment.

FIG. 6 shows a second embodiment of the present invention, and is a plan view of a diaphragm and an edge portion supporting the diaphragm.

FIG. 7 is a sectional view taken along the line II ′ of FIG. 6;

FIG. 8 is a sectional view taken along the line JJ ′ of FIG. 6;

FIG. 9 is a longitudinal sectional view of a conventional speaker provided with an up-roll type edge portion.

FIG. 10 is an explanatory diagram showing a difference in the amount of air removed by an up-roll type edge portion when the diaphragm moves in the front-back direction in the conventional speaker.

[Explanation of symbols]

7 Vibration plate 10 Edge portion 11 Inner circumference of edge portion 12 Tangential direction to inner circumference of edge portion 13 Circumferential direction of edge portion 14 Vibration surface of edge portion 15 Roll 16 Up roll 17 Down roll 18 Connect up roll and down roll The angle between the vibration plane and the plane for connecting the up / down roll

Claims (1)

[Claims] 1. A roll shape which is vertically symmetrical with respect to a vibrating surface 14 is alternately formed at equal intervals in a circumferential direction 13, and the inside of the roll shape is substantially along a tangential direction 12 of a curve 11 forming an inner circumference. The tangent line a drawn on the periphery and the vibrating surface 14
An electro-acoustic transducer having an edge connecting the above-mentioned vertically symmetric roll portions by a plane 18 formed by a certain range of angle α formed by the following.