JPH06178387A - Speaker - Google Patents

Abstract

PURPOSE:To reduce high frequency distortion in a sound pressure frequency characteristic, which is radiated from a free edge. CONSTITUTION:The free edge 11 is provided at the outer peripheral part of a corn-shape vibration plate 7 and the free edge 11 consists of role parts 12 and 14 whose cross section is a projected shape and the roll part 13 whose cross section is a recessed shape in a concentric circle shape The shape of the center roll part is made to be larger than the other roll parts and also the role part areas of the recessed part and the projected part are made to be almost equal. Thus, the synthesis of air quantity displaced by the projected roll part and the recessed roll part is made constant for the up and down amplitude of the free edge so that the non-symmetry of air displacement quantity is eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention reduces distortion caused by a free edge arranged between a diaphragm of a speaker and an outer peripheral frame portion, and is proportional to an electric signal without causing unnecessary resonance. The present invention relates to a high-performance speaker that reproduces generated sound waves.

[0002]

2. Description of the Related Art In recent years, since digital signal processing technology has made dramatic progress and the quality of electric signals supplied to a speaker has been greatly improved, a speaker capable of reproducing high-quality sound has been strongly desired. There is. A conventional speaker will be described below with reference to the drawings.

FIG. 5 is a sectional view showing the structure of a conventional speaker. Reference numeral 1 is a plate, 2 is a yoke integrally formed with the plate 1, 3 is a magnet fixed to the plate 1,
4 is a center pole fixed to the upper surface of the magnet 3, 5
Is a voice coil held in a magnetic gap formed by the outer circumference of the center pole 4 and the inner circumference of the yoke 2, 6 is a bobbin of the voice coil 5, 7 is a cone-shaped diaphragm fixed to the tip of the voice coil bobbin 6, 8 is a damper fixed to the outer periphery of the voice coil bobbin 6, and 9 is a cone type vibration plate 7.
A free edge provided on the outer peripheral portion of the frame 10 is a frame for fixing the outer periphery of the damper 8 and the free edge 9 and holding a magnetic circuit composed of the plate 1, the yoke 2, the magnet 3 and the center pole 4.

In the above structure, when an electric signal is applied to the voice coil 5, the driving force generated in the voice coil 5 is transmitted to the bobbin 6 of the voice coil and vibrates the cone-shaped diaphragm 7 fixed to the tip portion thereof. It is a thing.

[0005]

In such a conventional speaker, the cone-shaped diaphragm 7 is supported by the damper 8 and the free edge 9 fixed to the outer periphery of the bobbin 6 of the voice coil 5, and the support of these supports is provided. The linearity of the force becomes a problem during the reproduction of the low frequency range where the amplitude becomes large, which causes harmonic distortion.

Various shapes have been proposed for the damper 8 and the free edge 9 in order to improve the linearity of the supporting force of the support. The shape of the free edge that is mainly used at present is the roll shape as shown in Fig. 5 (the former),
A corrugated shape whose cross section is composed of a plurality of roll portions in which uneven shapes are alternately repeated (the latter) is used. The latter waveform-shaped free edge 9 has drawbacks that it is difficult to obtain a large vibration amplitude and edge resonance easily occurs. Further, the former roll-shaped free edge 9 is characterized in that a large amplitude can be easily obtained and that edge resonance hardly occurs.

At present, the most commonly used one is a roll shape as shown in FIG. 5, and the linearity of the supporting force of the support is greatly improved by the combination with the corrugated damper 8. It was However, here, the vibration mode of the roll-shaped free edge 9 is as shown in the cross-sectional view of the main part of FIG. In the figure, A is a neutral state before an electric signal is applied to the voice coil 5, B is a state in which it vibrates forward from the neutral point, and C shows a state in which it vibrates rearward from the neutral point.

In each vibration state, the cone-shaped diaphragm 7 has the same amplitude value ξ moving back and forth with respect to the neutral point. That is, the free edge 9 does not include a non-linear component in the operation of the cone-shaped diaphragm 7 as a support. However, as shown in FIG. 6, the amount of air removed by the free edge 9 which oscillates together with the cone-shaped diaphragm 7 is U1 when moving from the position A to the state B, and from the position A to the state C. If the amount of air when moving is U2, these values will be different due to deformation of the roll shape of the free edge 9.

Here, the sound pressure characteristic of the speaker is proportional to the sum of the cone diaphragm 7 and the amount of air removed by the free edge 9, but the sound pressure emitted from the free edge 9 is as described above. Since the amount of air removed varies depending on the front-back movement, it essentially includes distortion, and the sound pressure characteristics of the speaker always include distortion components.

FIG. 7 is a diagram showing the sound pressure frequency characteristics of a speaker having a diameter of 14 cm using a roll-shaped free edge 9. Here, the driving force generated by the voice coil 5 includes a non-linear component. To avoid this, a short voice coil system in which the winding width of the voice coil 5 is smaller than the magnetic gap length is adopted. Since the air removal amount of the free edge 9 is asymmetrical due to the front-back vibration, the second high-frequency distortion is generated in the low sound range of 100 Hz or less.

The present invention is to solve the above-mentioned problems. For the free edge, which is the support of the diaphragm, the high-frequency distortion caused by the asymmetry of air is significantly reduced without deteriorating the linearity of the support force. The purpose is to realize such a speaker.

[0012]

In order to achieve the above-mentioned object, the present invention comprises a roll portion having a cross section of a free edge which alternates irregularities, of which a concave or convex roll portion disposed in the central portion is formed. The size is larger than other roll parts, and the roll part areas of the concave part and the convex part are made substantially equal to each other, or the sizes of the roll parts are made different from each other, and the inner circumference or the outer circumference of the free edge is The diaphragm is joined to the outer edge or the inner edge of the free edge with a frame.

[0013]

According to the present invention, the cross-sectional shape of the free edge is composed of a plurality of roll portions in which irregularities are alternately repeated, and by making the roll portion areas of the concave and convex portions substantially equal, the amplitude of the diaphragm and the free edge The amount of air removed from the recess and the amount of air removed from the protrusion are symmetrical with respect to the neutral point when no air signal is applied, and the combined excluded air amount becomes equal to the vertical vibration. And the resonance frequency of each roll can be dispersed by making the shape of the roll part arranged in the center larger than the other roll parts, or by changing the size of each roll part. Disturbance of sound pressure characteristics can be improved.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 (a) is a structural cross-sectional view of the speaker in the first embodiment of the present invention, and FIG. 1 (b) is a plan view of (a). In the figure, the same components as those in the conventional example shown in FIG. 5 are designated by the same reference numerals.

The free edge 11 is largely different from the conventional example.
Is the shape of. As shown in the enlarged cross-sectional view of the free edge in FIG. 2, 12 and 14 are composed of small-sized convex roll portions, and 13 are composed of large-sized concave roll portions. The convex roll portions 12 and 14 and the concave roll portion 13 are set to have the same amount of air removed.

The operation of the above configuration will be described. When an electric signal is applied to the voice coil 5, the cone diaphragm 7 is displaced. At that time, the amount of air removed by the free edge 11 is, as described above with reference to FIG. 6, when it is displaced forward and backward. The displacement amount when displaced is different, and due to this, distortion occurs even if the cone-shaped diaphragm 7 is moved linearly. However, as shown in FIGS. 1 and 2, the present invention eliminates this distortion by arranging the convex roll portions 12 and 14 and the concave roll portion 13 in a mixed arrangement and making their areas substantially equal. Is. Furthermore, by changing the roll dimensions of the convex roll portion and the concave roll portion, the resonance frequency of each roll can be changed, and unnecessary disturbance of the sound pressure characteristic due to the free edge resonance which is likely to occur in the middle range is eliminated. Therefore, it is possible to reproduce a flat sound pressure characteristic.

The convex roll portions 12 and 14 and the concave roll portion 13 shown in FIG. 2 also function as the concave roll portion and the convex roll portion in the same manner as described above, contrary to the illustration.

FIG. 3 is 14 cm using the free edge of the present invention.
It is a sound pressure frequency characteristic of a speaker having a caliber. It can be seen that the second harmonic distortion is significantly reduced in the low sound range of 100 Hz or less in comparison with the characteristics of the conventional speaker described in FIG.

Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 4 shows an enlarged sectional view of the free edge in the second embodiment of the present invention. In the figure, the roll portions 15 and 17 of the free edge are convex portions and the roll portion 1
6 and 18 form a concave portion, and each roll portion 15, 16, 17, 1
The size of 8 is different, and it is possible to prevent and disperse the resonance at a single frequency, and reduce the disturbance of the sound pressure characteristic due to the free edge resonance.

[0020]

As described above, the loudspeaker of the present invention comprises a plurality of roll portions in which the cross section of the free edge alternately has an uneven shape, and, for example, a convex roll portion area,
The area of the concave roll is made approximately the same size, and the amount of air removed from the convex roll of the free edge is equal to the amount of air removed from the concave roll with respect to the vertical amplitude of the cone-shaped diaphragm. Then, the second harmonic distortion of the sound pressure characteristic caused by the asymmetry of the air elimination amount of the free edge which has been conventionally generated can be significantly reduced, and a low distortion speaker can be provided.

Moreover, the resonance frequency of the free edge can be dispersed by increasing the size of the central roll or by changing the size of the other rolls, which is the case with the conventional free edge having a corrugated shape. Disturbance of the sound pressure characteristic can also be reduced.

[Brief description of drawings]

FIG. 1 shows a speaker according to a first embodiment of the present invention, (a)
[FIG. 3] is a cross-sectional view showing the structure, and (b) is a plan view of (a).

FIG. 2 is an enlarged cross-sectional view of a free edge of the speaker shown in FIG.

FIG. 3 is a sound pressure frequency characteristic of a 14 cm diameter speaker adopting the free edge of the present invention.

FIG. 4 is an enlarged sectional view of a free edge of the speaker of the second embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a structure of a conventional speaker.

6 is a cross-sectional view of essential parts showing a vibration state of a free edge of the speaker shown in FIG.

FIG. 7: 14 cm using a conventional roll-shaped free edge
It is a sound pressure frequency characteristic figure of a diameter speaker.

[Explanation of symbols]

5 ... Voice coil, 7 ... Cone type diaphragm, 11 ... Free edge, 12, 14, 15, 17 ... Convex roll part, 13, 1
6, 18 ... Concave roll part.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tetsuji Koura 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] 1. A plurality of roll portions having a cross section in which concave and convex portions are alternately repeated between a diaphragm and an outer peripheral frame portion,
It is characterized in that the size of the concave or convex roll part arranged in the central part is larger than that of the other roll parts, and the free edge is arranged so that the roll part areas of the concave part and the convex part are substantially equal to each other. Speaker. 2. A plurality of rolls having alternating cross-sections having a concave-convex shape or a concave-convex shape between the vibrating plate and the outer peripheral frame part, and the roll-part areas of the convex part and the concave part are substantially equal to each other. A speaker characterized in that the rolls have different sizes.