JPH0730995A - Edge for speaker - Google Patents

Abstract

PURPOSE:To obtain an edge for speaker with which reproduced band width can be widened by lowering a minimum resonance frequency also in a speaker of a small diameter, high sound quality/high resistance input can be realized and high reliability can be realized. CONSTITUTION:An edge 10 for speaker is obtained by heating, pressurizing and molding a base material on which gum system resin containing curing agent is coated on chemical synthetic fiber which is excellent in moisture proof and has flexibility as base cloth in a desired shape. Thus, in the speaker for which this edge 10 for speaker is used, the lowest resonance frequency can be lowered and high reliability can be realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speaker edge used in various audio equipment.

[0002]

2. Description of the Related Art In recent years, computers and multimedia have come into widespread use, and there is a demand for a microspeaker capable of coping with the high sound quality and high input resistance. A conventional speaker of this type will be described below with reference to the drawings.

FIG. 4 is a half sectional view showing the structure of a conventional speaker. In FIG. 4, 1 is a magnetic circuit, 2 is a magnetic gap,
Reference numeral 3 is a voice coil fitted in the magnetic gap 2, 4 is a vibration plate coupled around the voice coil 3, 5 is a dust cap fixed to the upper end of the voice coil 3, and 6 is a damper fixed to the outer peripheral portion of the voice coil 3. , 7 are edges fixed to the outer circumference of the diaphragm 4, and 8 is a frame fixed to the outer circumferences of the damper 6 and the edge 7 and coupled to the upper surface of the magnetic circuit 1.

In the above structure, when an electric signal is applied to the voice coil 3, the diaphragm 4 is vibrated by the driving force generated in the voice coil 3. The damper 6 and the edge 7 support the voice coil 3 and the diaphragm 4 so as to vibrate only in the vertical direction, suppress radial movement, and also function as a spring in the vertical direction. This spring property resonates with the effective vibration mass Mms, and the frequency at that time is the minimum resonance frequency F.
This is generally referred to as “o”, and this Fo is generally regarded as the bass reproduction limit frequency of the speaker. Further, a constant indicating the spring characteristic of the entire speaker determined by the damper 6 and the edge 7 is called compliance Cms, and the relationship between them is expressed by the following equation.

Fo = 1 / (2π√ (Cms · Mms)) As described above, in order to reduce Fo in order to widen the bass reproduction band, it is preferable to increase the compliance Cms or the effective vibration system mass Mms. However, increasing Mms reduces the efficiency of the speaker and is not effective. Therefore, a method has been adopted in which Cms is increased, that is, the elasticity is reduced in flexibility. Particularly, in order to reduce the flexibility in edge 7, the base material of edge 7 is integrated with diaphragm 4. As a fixed edge made of natural pulp or as a free edge to be attached to the vibration plate 4, S as a sealing material
A molded product of a cotton base cloth coated with a rubber-based resin such as BR or NBR or a molded product of a urethane foam sheet has been used.

[0006]

However, in the above conventional configuration, when a fixed edge made of natural pulp integrated with the diaphragm 4 is used as an edge for a small speaker having a diameter of about 3 cm, the edge is Since it is integrated with the diaphragm, it is not only difficult to obtain the amplitude, but also the strength is low, and cracks are likely to occur at the edge part, so it is unreliable, and the lowest resonance frequency (Fo) is lowered. There was a limit, and there was a problem that it was difficult to reproduce bass. Also, the free edge to be attached to the diaphragm 4 is applied at a temperature of about 200 ° C. after impregnating a cotton base cloth coated with a rubber resin such as SBR or NBR as a sealing material with a phenol resin as a thermosetting resin. Although it is pressure molded, the physical strength of the cotton base fabric is deteriorated by this heat and pressure molding because the cotton base fabric itself is inferior in heat resistance, and the cotton base fabric is subjected to water resistance and moisture resistance life test. And the edge 7 are deformed, the linearity with respect to the speaker input is poor, and the minimum resonance frequency (F
There was a problem that the reduction rate of o) was large.

Further, the edge formed by molding the urethane foam sheet has weak physical strength, lacks wet heat resistance and weather resistance, and many problems remain to be solved in terms of reliability. In a small-diameter speaker with high performance, there is a problem that it is not possible to obtain a lightweight, highly flexible speaker edge having excellent flexibility.

The present invention has improved the above-mentioned conventional drawbacks, is rich in flexibility, has a strong physical strength, is excellent in moist heat resistance and weather resistance, has a good linearity with respect to a speaker input, and has a minimum resonance at a high input resistance. It is an object of the present invention to provide a highly reliable speaker edge having a low frequency (Fo) reduction rate.

[0009]

In order to solve the above-mentioned problems, a speaker edge according to the present invention heats a chemically synthesized fiber coated or impregnated with a rubber-based resin containing a vulcanizing agent to a desired shape. The edge for the speaker is configured by pressure molding.

[0010]

With this configuration, it is possible to obtain a speaker edge which is not only excellent in flexibility and high in physical strength, but also excellent in wet heat resistance, weather resistance and linearity. Further, the speaker using this speaker edge has a low decrease rate of the minimum resonance frequency (Fo) at the time of high withstand input, and is a speaker with low Fo and excellent reliability even if it is a small speaker.

[0011]

EXAMPLES An example of the present invention will be described below.
FIG. 1 is a cross-sectional view showing a structure of a speaker edge according to the same embodiment. This speaker edge 10 is a synthetic fiber polyester excellent in moist heat resistance and weather resistance (a polyester yarn having a thickness of 50 denier is a warp yarn per inch). 98,
30 g / m of a rubber material such as SBR and NBR containing a vulcanizing agent with excellent flexibility in a plain weave cloth woven with 100 wefts
^{It is obtained by} applying ² coating, drying this, and then heat-pressing this substrate into a desired shape. In addition, the above heat and pressure molding is performed at a temperature of 185 to 1 so as not to deteriorate the substrate.
It is carried out under the conditions of 95 ° C., pressure of 1 kg / m ² and pressurizing time of 6 seconds. When the temperature becomes higher than 200 ° C., the deterioration of the base material becomes severe, and at 230 ° C. or higher, the base material softens and finally This is because the function cannot be maintained due to melting.

The thus-obtained speaker edge according to the present invention not only has excellent performance against vibration and bending, but also has good linearity with respect to the input of the speaker when incorporated into the speaker. At the time of high withstand input, the minimum resonance frequency (Fo) is reduced at a very low rate, and excellent reliability is exhibited. The lowest resonance frequency (Fo) of the speaker using the speaker edge according to the present invention and the conventional speaker using the speaker edge.
The rates of change in the above are compared and shown in (Table 1).

[0013]

[Table 1]

Further, the force comparing the linearity of the speaker edge according to the present invention and the conventional speaker edge-
The displacement characteristic is shown in FIG. 2, and it is better that the area surrounded by the hysteresis curve in FIG. 2 is smaller. In addition, the speaker edge of the present invention is extremely lightweight and highly flexible, has good physical strength, and can sufficiently withstand moisture resistance, and is suitable for a speaker for large input. The results of the reliability comparison with the conventional product are shown in (Table 2).

[0015]

[Table 2]

As is clear from this (Table 2), only the speaker using the speaker edge of the present invention was satisfactory in its moisture resistance without deformation. In addition, the reliability of the micro speaker has always been guaranteed, and Fo of 300
It was difficult to set the frequency to Hz, but the speaker using the speaker edge of the present invention makes it possible, and the flexibility of the edge at this time is a displacement of 0.9 mm at a load of 20 g, which results in low bass. The reproduction band can be expanded. Further, the sound pressure frequency characteristics are shown in FIG. 3. In FIG. 3, both the speaker of this embodiment and the conventional speaker use a micro speaker having a diameter of 3 cm.

[0017]

As described above, the speaker using the speaker edge according to the present invention has a minimum resonance frequency (Fo) of 3 or less.
Since it can be lowered to 00 Hz, not only can the playback band be widened and it can withstand large amplitudes well, it also has excellent humidity resistance, good linearity with respect to speaker input, and high input resistance. At the same time, it has an advantage that it is possible to provide a small speaker with high reliability, which has a very small change rate of the minimum resonance frequency (Fo), is highly reliable, and is of great industrial value.

[Brief description of drawings]

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

FIG. 2 is a characteristic diagram comparing force-displacement characteristics of speaker edges in the present invention and a conventional product.

FIG. 3 is a characteristic diagram comparing sound pressure frequency characteristics of a speaker using a speaker edge in the present invention and a conventional product.

FIG. 4 is a half sectional view showing a configuration of a speaker according to the present invention and a conventional product.

[Explanation of symbols]

 1 magnetic circuit 2 magnetic air gap 3 voice coil 4 diaphragm 5 dust cap 6 damper 7 edge 8 frame 10 edge

Claims (5)

[Claims] 1. An edge for a loudspeaker, which is formed by heat-pressing a base material having a chemically synthetic fiber cloth coated or impregnated with a rubber-based resin containing a vulcanizing agent and dried into a desired shape. 2. The speaker edge according to claim 1, wherein polyester is used as the chemically synthesized fiber. 3. The speaker edge according to claim 1, wherein the chemically synthetic fiber is a polyester woven by using a twisted yarn having a yarn diameter of 60 denier or less obtained by twisting a large number of ultrafine fibers. 4. The speaker edge according to claim 1, wherein SBR, NBR or the like is used as the rubber resin. 5. The surface temperature of the mold at the time of heat and pressure molding is 18
The speaker edge according to any one of claims 1 to 4, which is molded at 5 to 195 ° C.