JPH0777479B2 - Support member for electroacoustic transducer - Google Patents

Description

TECHNICAL FIELD The present invention relates to an improvement of an electroacoustic transducer support member such as an edge and a damper.

[Prior Art] A support member of this type will be described, for example, for a speaker edge. After a cotton cloth or the like is impregnated with a thermosetting resin, it is coated with a viscoelastic material such as rubber and heated to a predetermined edge shape. Molded coated cloth edge A urethane foam edge formed by heat-molding a urethane foam sheet into a predetermined edge shape was often used. A thermoplastic urethane elastomer edge was formed by extruding a thermoplastic urethane elastomer into a sheet and then press-molding into a predetermined shape.

[Problems to be Solved by the Invention] The above-mentioned conventional edge has various unsatisfactory points. For example, the linearity of the input-displacement characteristic is not good because the elasticity of the material itself is insufficient. Further, since the coating amount of the viscoelastic material is limited due to the increase in weight due to the coating layer, the internal loss cannot be substantially obtained, and the damping effect of high-frequency resonance is poor, and it is difficult to obtain a flat frequency characteristic. I have a problem.

Further, the stretchability of the edge is better than that of the above-mentioned edge, but it has the same problem as the edge with insufficient internal loss, and further, the light resistance is poor and the physical properties are significantly deteriorated by light, especially ultraviolet rays. There was a problem.

Further, the edge is superior in elasticity and internal loss as compared with the above two types of edges.

However, the conventional thermoplastic urethane elastomer used polyadipate as the polyol of the main component, but the thermoplastic urethane elastomer using the polyadipate has poor water resistance and has a problem in use in a humid atmosphere, and thus has a heat resistance. Since its properties are not sufficient (at most 70 ° C), there was a problem in using it in a hot and humid atmosphere.

[Means for Solving the Problem] The present invention is a support member for an electroacoustic transducer, which is composed of a thermoplastic urethane elastomer obtained by polyaddition reaction of polyhexamethylene carbonate and diisocyanate.

[Operation] From the points of good water resistance, sufficient internal loss, and good heat resistance of the support member, it is possible to effectively support the object to be supported, good frequency characteristics, and poor conditions. It was possible to provide an electro-acoustic transducer that can be used in a machine and that does not change over time.

[Examples] Hereinafter, the present invention will be described with reference to Examples.

Product as a polycarbonate-based thermoplastic urethane elastomer Akira Pandex T-6990 (Dainippon Ink and Chemicals, Inc.)
Was manufactured by extrusion molding into a sheet having a thickness of 0.3 mm, and the sheet was further vacuum formed into an edge having a shape shown in FIG.

And the speaker 1 was manufactured using the said edge.

On the other hand, as a comparative example, a conventional polyadipate-based thermoplastic urethane elastomer, trade name Pandex T-5167 (manufactured by Dainippon Ink and Chemicals, Inc.) was used to prepare an edge having the same shape as that shown in FIG. Speaker 2 was obtained using the edge.

[Effects of the Invention] The speaker 1 of the example of the present invention and the speaker 2 of the comparative example are arranged in an atmosphere of 70 ° C. and a humidity of 95%.
The white noise of W was input and the continuous operation test was performed to measure the change of the lowest resonance frequency ₀ , and the result of FIG. 2 was obtained.

As is clear from the result, the speaker 1 using the polycarbonate-based thermoplastic urethane elastomer edge
₀ to changes that little, ₀ of the speaker 2 using polyadipates based thermoplastic urethane elastomer edge
In the continuous operation of 300 hours, ₀ was reduced by approximately 24% in the comparative example speaker 2, whereas ₀ was reduced by approximately 8% in the speaker 1 of the present invention.

Next, the loudspeakers 1 and 2 were placed in an atmosphere of 80 ° C. with their opening surfaces vertical, and the edge sag, that is, the change in the vertical position of the uppermost point of the diaphragm was measured with the passage of time.
The results shown in the figure were obtained.

From this result, it was found that the speaker 1 of the present invention has less edge droop and is superior in heat resistance to the speaker of the comparative example.

[Brief description of drawings]

FIG. 1 is a front view of the edge of the embodiment, FIG. 2 is a ₀ -operating time characteristic diagram of the speaker of the invention and the speaker of the comparative example, and FIG. 3 is a position of the diaphragm of the speaker of the invention and the speaker of the comparative example. It is a change-time characteristic view.

Claims (1)

[Claims] 1. A support member for an electroacoustic transducer, comprising a thermoplastic urethane elastomer obtained by polyaddition reaction of polyhexamethylene carbonate and diisocyanate.