JP2000333291A - Loudspeaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a loudspeaker used for various acoustic devices the reproduction frequency band of which loudspeaker is extended by solving a problem of reduction in a sound pressure level of a high frequency sound due to reflection of vibration caused at a deflection point resulting from a shape of a diaphragm of the loudspeaker the shape of the diaphragm of which is oval, elliptic, nearly rectangle, or nearly square. SOLUTION: The loudspeaker is configured with a diaphragm 8 whose cross sectional shape on straight lines passing through nearly a center of a voice coil 6 and tying a voice coil coupling section and an outer ridge line is formed by straight lines or curves without a deflection point at any position so as to enhance the stiffness of the diaphragm 8 and to eliminate spurious vibration and then the sound pressure level at a high frequency band can be enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a loudspeaker used for various kinds of audio equipment, and more particularly to a loudspeaker whose diaphragm has an oval, elliptical, substantially rectangular, or substantially square shape. .

[0002]

2. Description of the Related Art In recent years, loudspeakers having an elliptical shape or a substantially rectangular shape, in which the outer shape of a loudspeaker is more effective than a round or an elliptical shape, are mainly used for television receivers. In some cases, the speaker having such a shape is frequently used.

Hereinafter, the above-mentioned conventional speaker will be described with reference to the drawings. FIG. 5 is a half-sectional view showing the structure of the above-mentioned conventional speaker, FIG. 6 is a plan view showing the shape of a cone-shaped diaphragm used in the speaker, and FIGS.
Shows the cross-sectional shape of the diaphragm in an arbitrary direction connecting the center and the outer edge of the diaphragm.

In the conventional speaker shown in FIG. 5, a ring-shaped main magnet 2 and an upper plate 3 are concentrically fixed to a lower plate 1 having a cylindrical pole portion at the center. A magnetic gap 4 is formed between the cross section and the upper portion of the pole portion of the lower plate 1. A frame 5 is connected to the upper plate 3, and a winding portion of the voice coil 6 is fixed to the frame 5 via a damper 7 so as to be positioned at the center of the magnetic gap 4. A cylindrical bobbin of the voice coil 6 and a voice coil connecting portion of the diaphragm 8 are bonded together, and an outer peripheral portion (edge portion) of the diaphragm 8 is bonded to the frame 5 by bonding. In order to prevent the magnetic field generated in the magnetic gap 4 from leaking to the outside, a cancel magnet 9 is connected to the bottom surface of the lower plate 1, and a shield cover 10 is further connected to the entire field portion.

[0005] A dust cap 11 is joined to the upper part of the voice coil 6 so that foreign matter or the like does not enter the magnetic gap 4.

[0006] The operation principle of the conventional loudspeaker configured as described above will be described below. The voice coil 6 arranged at the center of the magnetic air gap 4 forming the parallel magnetic field,
When an electric input is applied, a vertical force is generated according to Fleming's left-hand rule. This force is transmitted from the voice coil 6 to the diaphragm 8 via the cylindrical bobbin. The diaphragm 8 vibrates the air on the front surface to generate sound.

The diaphragm 8 has a structure and a shape as shown in the plan view of FIG.
The ridgeline 16 is constituted by four surfaces 3, 14 and 15, and the boundaries between the surfaces are connected by an appropriate radius.

FIGS. 7A to 7F show cross-sectional shapes in any direction connecting the center axis of the diaphragm 8 and the outer edge.

When the cut is made on all the surfaces passing through the central axis of the voice coil connection portion of the diaphragm 8, the ridge line portion 16
Were formed so as to have a bent portion or an inflection point, respectively.

[0010]

However, in the above-described conventional configuration, the structure of the diaphragm 8 is four-dimensionally viewed from the center axis of the diaphragm 8 with respect to the vibrating portion outer edge line excluding the edge portion. Ridge line 16 was formed.
That is, when cut on all planes passing through the central axis of the voice coil connection portion of the diaphragm 8, four ridge portions 16
Does not become a straight line or a curve having no inflection point, and a bent portion occurs. Therefore, the vibration transmitted from the voice coil 6 propagates radially from the circumference of the voice coil connection portion of the diaphragm 8 to the outer peripheral portion. Vibration is reflected at the portion 16 and the rigidity of the diaphragm 8 is reduced.

This phenomenon has been observed in a round diaphragm from the past.
It is known that a bent part is intentionally provided on the top of the diaphragm to lower the high frequency limit frequency (hereinafter referred to as fh) of the speaker sound pressure frequency characteristic to a lower one and to rapidly attenuate the sound pressure level above fh. As a result, the sound pressure-frequency characteristics of a speaker using a diaphragm having an oval, substantially rectangular The attenuation of the band level (fh or higher) is remarkable, and many of them have a high frequency level on the amplifier circuit side.
It required a dB-up correction.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and aims to reduce the load on the amplifier-side circuit by improving the sound pressure level in a high frequency band (fh or higher) in the frequency characteristics of a speaker. It is assumed that.

[0013]

According to the present invention, there is provided a loudspeaker according to the present invention, wherein an outer edge of a vibrating portion excluding an edge portion has a cone shape having an elliptical, elliptical, substantially rectangular, or substantially square shape. The diaphragm is passed so that the cross-sectional shape on a straight line that passes through the approximate center of the voice coil of the diaphragm and connects the voice coil connection portion and the outer edge line is a straight line or a curve without an inflection point at any position. It is composed.

According to the above configuration, the vibration transmitted from the voice coil propagates radially from the circumference of the voice coil connecting portion of the diaphragm to the outer peripheral portion. However, the diaphragm is formed into a straight or curved cross-sectional shape, as in the prior art. Since there is no bent portion at the ridge portion, the reflection of vibration at the inflection point is eliminated, the rigidity of the diaphragm is improved, and the sound pressure attenuation in a high frequency band (fh or more) is improved.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a half sectional view showing a configuration of a speaker according to an embodiment of the present invention, and its configuration and operation principle are the same as those of the prior art shown in FIG. Yes, the same numbers are assigned and the description is omitted.

FIG. 2 is a plan view showing an example of a cone-shaped diaphragm 8 used in the speaker of the present invention. The diaphragm 8 has a voice coil coupling portion at the center, and the outer edge of the diaphragm is formed in an oval shape. It has a structure. FIGS. 3A to 3F show cross-sectional shapes of arbitrary straight lines OA to OF passing through the center of the diaphragm 8 and connecting the voice coil coupling portion and the outer edge line.
Shown in As described above, the diaphragm 8 of the speaker according to the present invention is used.
Has a configuration in which the cross-sectional shape is formed linearly at any position connecting the voice coil coupling portion and the outer edge line, and there is no inflection point.

Since the oblong diaphragm 8 having such a shape and structure has no inflection point, reflection of vibration at the inflection point does not occur, and the rigidity of the diaphragm 8 is improved. When the vibration propagates radially from the circumference of the voice coil coupling portion of the diaphragm 8 to the outer peripheral portion, it is possible to increase fh in the sound pressure frequency characteristics of the speaker and to improve the sound pressure level above fh. FIG. 4 shows a comparison between sound pressure frequency characteristics of a speaker using the diaphragm 8 according to the present embodiment and a speaker using a conventional diaphragm.

As is apparent from FIG. 4, the speaker according to the present embodiment can obtain a remarkable effect for wideband reproduction by extending fh and improving the level in a high frequency band.

In the present embodiment, the case where the cross section of the diaphragm 8 is formed as a straight line has been described. However, it goes without saying that the same effect can be obtained even if the diaphragm 8 is formed with a curve having no inflection point.

It is needless to say that the same effect can be obtained when the outer edge line shape of the diaphragm 8 is elliptical, substantially rectangular, or substantially square in addition to the elliptical shape.

In the above embodiment, the cross-sectional shape on a straight line passing through the approximate center of the diaphragm is described as a straight line or a curve. However, this is the center position of the vibration, and may be called the center of the voice coil. Good thing.

[0023]

As described above, in the speaker according to the present invention, the cross-sectional shape of the line passing through the approximate center of the voice coil and connecting the voice coil coupling portion and the outer edge line has no straight line or inflection point at any position. By using a speaker that uses a cone-shaped diaphragm with a curved structure, the rigidity of the diaphragm is improved, the reflection of vibration at the inflection point is eliminated by eliminating the inflection point, and the frequency characteristic is fh By extending the extended reproduction frequency and improving the sound pressure level in the high frequency band, it is possible to obtain effects such as reduction of the load on the amplifier-side circuit.

[Brief description of the drawings]

FIG. 1 is a half sectional view showing a configuration of a speaker according to an embodiment of the present invention.

FIG. 2 is a plan view showing a configuration of a diaphragm which is a main part of the same.

FIG. 3 is a schematic half sectional view showing the shape of the diaphragm in each section of the diaphragm shown in FIG. 2;

FIG. 4 is a diagram showing a frequency characteristic of the speaker and a frequency characteristic of a speaker according to the related art.

FIG. 5 is a half sectional view showing a configuration of a conventional speaker.

FIG. 6 is a plan view showing a configuration of a diaphragm which is a main part of the same.

7 is a schematic half sectional view showing the shape of the diaphragm in each section of the diaphragm shown in FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lower plate 2 Main magnet 3 Upper plate 4 Magnetic gap 5 Frame 6 Voice coil 7 Damper 8 Diaphragm 9 Cancel magnet 10 Shield cover 11 Dust cap

Claims (1)

[Claims] 1. A frame is coupled to a magnetic circuit having an annular magnetic air gap, and a cone-shaped diaphragm having a voice coil coupled to a central portion thereof is coupled to an outer peripheral portion of the frame. The diaphragm is fitted into the gap, and the diaphragm excluding the edge portion has an oval, elliptical, substantially rectangular, or substantially square outer edge line, substantially passes the center of the voice coil, and vibrates with the voice coil coupling portion. A loudspeaker in which the cross-sectional shape of a straight line connecting the outer edge line of the plate is a straight line or a curve having no inflection point at any position.