JPH0468700A - Voice coil bobbin - Google Patents

Abstract

PURPOSE:To obtain voice coil for speaker without anisotropy and with heat resistance, light weight, and high elasticity by using rod-like high polymer materials (PBT), (PBZT), and (PBO). CONSTITUTION:The rod-like high polymer material is composed of polybenzobisthiazole(PBT), polybenzthiazole(PBZT), or polybezoxazole(PBO). Since the characteristics of the essential advantage of the macromolecular material such as high elasticity, and high rigidity are used, the voice coil has large rigidity and the extremely small coefficient of thermal expansion of the material, and high heat resistance at the time of assembling it to the speaker. Thus the deformation of the bobbin and the stripping of the adhesion to a lead wire can be prevented and the defective magnetic air gap rubbing can be eliminated even when large power is inputted. Since specific gravity is small, the mass of the voice coil is decreased, electroacoustic conversion efficiency can be taken high, and the highest frequency of the reduced sound is high. Therefore, a reproduction sound area is broadly expanded.

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to a bobbin for an electroacoustic transducer, such as a voice coil of a speaker, using a novel material.

<Prior art> Conventionally, the voice coil bobbin of this type of speaker was made by cutting paper into a rectangular shape, joining both ends together and rolling it into a cylindrical shape to form a bobbin, and then winding a conductive wire on top of the bobbin. thing. Thin foil of metal such as aluminum is rolled into a bobbin in the same way as above. A bobbin made by similarly rolling a heat-resistant resin film such as polyamide or polyimide is often used.

<Problems to be Solved by the Invention> Therefore, the conventional voice coil bobbin of this type has had the following problems. Paper bobbins generally have poor heat resistance and shrink to a large degree due to heat, so that the contact with the fill conductor wound on top of the bobbin may peel off, resulting in poor magnetic gap friction. Furthermore, since the bobbin made of metal foil is conductive, an eddy current is generated and vibrations are suppressed, which deteriorates the quality of reproduced sound. Furthermore, voice coil bobbins made of polyamide, polyimide, etc. have a large coefficient of thermal expansion and anisotropy of expansion, so they have various problems such as deformation and magnetic air N friction defects6. The present invention eliminates such conventional problems! In order to solve the problem, it is an object of the present invention to provide a voice coil bobbin molded using a new material that is heat-resistant and has a low coefficient of thermal expansion.

<Means for solving m's> The present invention for achieving the object will be described based on examples.
Rod-shaped polymer material without directionality (P B T ), (
By using P B Z T ), (P B O), there is no anisotropy, high heat resistance, low coefficient of thermal expansion,
A lightweight, highly elastic voice coil for speakers.

<Function> Since the present invention has such a configuration, there are two physical advantages of the material: there is no difference depending on the direction of the elastic modulus;
Because it skillfully utilizes the physical properties of high elastic modulus and high rigidity, it can be used as an optimal voice coil bobbin when incorporated into a speaker, enabling excellent sound reproduction.

<Example> Examples of the present invention will be described below.

In this example, an extruded PBZT sheet is biaxially stretched to form a sheet with a thickness of 50 μm. This sheet is 0.1μ in length! The following microfibril network is formed, each at Oo 45° 90
The coefficient of linear thermal expansion in the direction is -7' to -3 ppm/'C
It has been confirmed that it has isotropy within the range of . next,
The physical properties of this sheet and the product of the present invention molded into a voice-fill bobbin are compared with those of the conventional example.

(Left below) The molecular structural formula of (P B Z T ) is as follows.

The voice coil bobbin has high rigidity, extremely low coefficient of thermal expansion of the material, and high heat resistance, so even if a large electrical input is applied, the bobbin will not deform or the bond with the conductor will peel off. There will be no magnetic gap friction defects.

In addition, because the specific gravity is small, the mass of the voice coil is small, the electroacoustic conversion efficiency is high, the maximum frequency of the reproduced sound is high, and the reproduced sound range can be expected to be widened. It has come to this.

Although the embodiments considered to be representative of the present invention have been described above, the present invention is not necessarily limited to the structure of these embodiments. It can be implemented with appropriate modification within the scope of achieving the following effects.

<Effect of the invention> Agent: Patent attorney: Yatabe

Claims (4)

[Claims] (1) A voice coil bobbin using a biaxially stretched film whose main component is a rod-shaped polymer material. (2) A voice coil bobbin, wherein the rod-shaped polymer material according to claim (1) is polybenzobisthiazole (PBT). (3) A voice coil bobbin, wherein the rod-shaped polymer material according to claim (1) is polybenzthiazole (PBZT). (4) A voice coil bobbin, wherein the rod-shaped polymer material according to claim (1) is polybenzoxazole (PBO).