JPH07108036B2 - Speaker - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speaker, and more particularly to a speaker having an annular edge on a peripheral portion of a cone.

[Conventional technology]

Conventionally, the cone-shaped speaker is provided with an edge in order to support the peripheral portion of the cone and to block the air flow before and after the cone.

This edge particularly affects the characteristics in the middle and high frequencies.
That is, it resonates with the cone due to the natural vibration of the edge, which causes distortion of sound.

In order to suppress such edge resonance, the following method has been conventionally used.

 Apply damping material to the edge surface.

 A material with large internal loss is used for the edge.

[Problems to be solved by the invention]

However, in the case of the method (1), the vibration damping effect was not sufficient because the high molecular organic material which is a conventional vibration damping agent has high hardness, low viscosity and high elasticity.

Also, in the case of method, as a material with large internal loss,
Butyl rubber has been conventionally used, but its vibration damping effect is not sufficient, its frequency characteristics are not flat as shown in FIG. 5 (A), and its distortion characteristics are also preferable as shown in FIG. 5 (B). Was not.

[Purpose of the present invention]

It is an object of the present invention to provide a speaker that overcomes the above-mentioned problems of the prior art, has a large damping effect, has a flat frequency characteristic, and reduces distortion.

[Outline of Invention]

The present invention uses, for example, NR, SB as the edge of the speaker.
R, CR, IIR, EPDM, NBR, ECO, a rubber composition prepared by blending a raw material rubber selected from the group consisting of norbornene polymers and the like with any of coumarone resin, petroleum resin or terpene resin as a tackifier. Is used alone or in combination with a woven or non-woven fabric and vulcanized and molded.

The vulcanization referred to here is to crosslink with sulfur or the like between chain-like molecules of rubber, and this vulcanization can improve elasticity. Further, the vulcanization molding is to simultaneously vulcanize the unvulcanized rubber by heating and pressurizing it in the mold.

Example of Invention

 Hereinafter, the present invention will be specifically described with reference to the drawings.

FIG. 1 is a sectional view of a cone type speaker according to an embodiment of the present invention. In the figure, 1 is a frame, 2 is a plate, 3 is a magnet, and 4 is a pole yoke.
A magnetic circuit is configured by the members 4 to 4.

A voice coil bobbin 6 around which a boil coil 5 is wound is provided in an annular magnetic gap formed in this magnetic circuit so as to be movable in the axial direction. The voice coil bobbin 6 is connected to the frame 1 by a damper 7 for holding the center thereof.

On the other hand, a cone (vibration plate) 8 provided in the frame 1
Is fixed to the upper end of the voice coil bobbin 6 at the bottom thereof, and is connected to the peripheral edge of the frame 1 via an annular edge 9 provided at the upper peripheral edge.

The shape of the edge 9 may be either a roll shape as shown in FIG. 2 (A) or a corrugation (fold) shape as shown in FIG. 2 (B).

Reference numeral 10 is a gasket provided on the horizontal upper portion of the frame 1.

FIG. 3 shows a concrete composition example of the rubber composition used as the edge 9 of the speaker according to the present invention and its physical property values.

In the example of FIG. 3, as raw rubber, IIR (trade name "Butyl 301", "Butyl 206"), EPDM (trade name "Esprene-505", "Esprene-600"), NBR (trade name " Nipol DN-207 "), ECO (trade name" Epichroma-
C ”), norbornene polymer (trade name“ NOSOLEX ”is used, and each of these raw material rubbers is provided with either coumarone resin, petroleum resin or terpene resin as a tackifier,
Each of them is a predetermined amount by weight.

The tackifier added to each raw material rubber is appropriately selected according to the compatibility with the raw material rubber (for example, whether or not kneading is possible). Further, desired additives (softening agent, filler, vulcanizing agent, vulcanization accelerator, lubricant, etc.) are added as necessary.

As can be seen from FIG. 3, when coumarone resin, petroleum resin or terpene resin is added to the raw material rubber as a tackifier, the impact resilience is 20% or less as compared with the conventional butyl rubber composition given as a comparative example. Also, the peak value of the internal loss coefficient tan δ is 0 to 40 ° C and is 0.
It is as large as 5 or more, and a sufficient damping effect can be obtained. Therefore, the edge 9 having a large vibration damping effect can be obtained by vulcanizing and molding these rubber compositions alone or in combination with a woven or non-woven fabric.

The internal loss coefficient tan δ of the rubber composition has a peak value of 0.
The composition ratio of the tackifier must be 25 parts by weight or more per 100 parts by weight of the raw rubber in order to make the composition exist within -40 ° C.

The reason why the internal loss is increased and the impact resilience is decreased by blending the raw rubber with any one of the coumarone resin, the petroleum resin and the terpene resin as the tackifier is as follows.

That is, a tackifier such as coumarone resin, petroleum resin, or terpene resin works like a glue in which the resin particles penetrate between the rubber molecules and stick the rubber molecules to each other. Rubber deforms when an external force is applied, which means that polymer chains are distorted and entangled at the molecular level. Therefore, when the external force is removed, the entangled polymer chains also try to return to their original state, but at that time, friction occurs between the molecules, and the energy stored in the rubber due to deformation is dissipated as heat. As a result, the internal loss increases and the impact resilience of the rubber decreases.

In FIG. 3, hardness, impact resilience and compression set were based on JIS-K6301 vulcanized rubber physical test method. The internal loss coefficient tan δ was measured using “Vibron” manufactured by Toyo Baldwin Co., Ltd.

Next, a method for manufacturing the edge 9 used in the speaker of the present invention will be described.

First, when the edge 9 is made of the rubber composition alone shown in FIG. 3, the edge may be formed by molding as in general rubber molding.

In addition, by combining with a woven or non-woven fabric, the edge 9
In the case of manufacturing, the method may be one of the following (a) and (b).

(A) A sheet of unvulcanized rubber composition is rolled and cut on at least one surface of a woven or non-woven fabric, and the resulting sheet is superposed and vulcanized integrally by heating and pressing. The heating / pressurizing conditions at this time are a heating temperature of 130 to 170 ° C. and a pressurizing pressure of 50 to 100 Kgf / cm ^2, and these are applied simultaneously.

(B) An unvulcanized rubber composition is applied to at least one surface of a woven or non-woven fabric, and vulcanized and molded integrally by heating and pressing. The heating / pressurizing conditions may be the same as those in (a).

As the material of the woven or non-woven fabric, natural fibers such as cotton and silk, synthetic fibers such as nylon, polyester and aramid, and inorganic fibers such as glass and carbon can be used. The woven or non-woven fabric may be impregnated with a resin such as phenol / melamine / epoxy / urethane.

A damping agent may be further applied to the edge surface in order to give a further damping effect to the edge obtained as described above.

FIG. 4 shows the frequency characteristics and the distortion characteristics of the cone type speaker according to the present invention constituted by using the edge made of the rubber composition of Example 1 in FIG. 3 as a representative of the embodiment of the present invention. Show. It can be seen from the frequency characteristic of FIG. 9A that the frequency characteristic is flattened in the mid-high range and that the harmonic distortion characteristic of FIG.

〔The invention's effect〕

As described above, since the speaker of the present invention uses the rubber composition having large internal loss and small repulsion elasticity for the edge, it is possible to increase the vibration damping effect of breathing acoustic vibrations as compared with the conventional speaker. it can. Therefore, the frequency characteristics in the mid-high range can be flattened and the distortion can be reduced, so that the band can be widened and a sound with better sound quality can be radiated as compared with the conventional speaker.

Further, since the speaker of the present invention is less deteriorated with time, it is possible to radiate a good sound stably for a long period of time.

[Brief description of drawings]

1 is a sectional view of a cone-shaped speaker according to an embodiment of the present invention, FIG. 2 is a sectional view showing an example of the shape of an edge, and FIG. 3 is a rubber composition used for the edge of the speaker according to the present invention. FIG. 4 is a diagram showing a specific composition example and its physical property values, FIG. 4 is a characteristic diagram of a speaker according to the present invention, and FIG. 5 is a characteristic diagram of a conventional speaker. 1 ... Frame, 3 ... Magnet, 8 ... Cone, 9
…… Edge.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shoichiro Terauchi 4-2610 Hanazono, Tokorozawa, Saitama Pioneer Co., Ltd. Tokorozawa Plant (72) Inventor Katsumi Kinoshita 4-2610 Hanazono, Tokorozawa, Saitama Pioneer Co., Ltd. Tokorozawa factory

Claims (1)

[Claims] 1. A vulcanization molding of a rubber composition obtained by blending a raw rubber with either a coumarone resin, a petroleum resin or a terpene resin as a tackifier alone or in combination with a woven or non-woven fabric. A speaker having a curved edge.