JPS60139098A - Speaker diaphragm - Google Patents

Abstract

PURPOSE:To obtain a light-weight speaker diaphragm which excels in the characteristics by using chiefly the thermoplastic polyether imido resin to form a film and therefore using a resin material having high heat resistance for a diaphragm. CONSTITUTION:A film made chiefly of amorphous thermoplastic polyether imido resin is used to a diaphragm for speaker. For the basic structural formula of said film, the specific gravity is set at about 1.2 with 19,000kg/cm<2> elastic modulus and 9.11 loss respectively. A vacuum molding process is applied to produce a conical diaphragm having 50mm.phi diameter and 50mum thickness. This diaphragm excels in the heat resistance and the burning resistance with light weight and is suited to an on-vehicle speaker, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a diaphragm for a speaker with excellent heat resistance, characterized in that the diaphragm is made of a resin material with good heat resistance.

Conventionally, speaker diaphragms made of plastic include
Polyethylene terephthalate film has been used. In the case of a speaker, the vicinity of the voice coil, which is the driving source, reaches a high temperature when the speaker is driven, so it is desirable that the diaphragm be made of a heat-resistant material that can sufficiently withstand high heat. However, the continuous use temperature of polyethylene terephthalate is 120° C., and for applications requiring higher heat resistance, A2 is easily used as a material.

Further, the diaphragm is required to move in accordance with the drive input due to its reproduction characteristics, and is desired to be as lightweight as possible. In general, in terms of weight reduction, it is better than metal and inorganic materials.
Plastic diaphragms are more advantageous.

Therefore, the present invention was devised to provide a diaphragm for a speaker that is highly heat resistant and lightweight as described above. That is, in the present invention, a diaphragm for a speaker is made by molding a film mainly composed of an amorphous thermoplastic polyether resin. Examples of amorphous thermoplastic polyetheroid resins include those having repeating units (manufactured by GK, USA).

The specific gravity of this film is around 1.2, which is lower than the specific gravity of polyethylene terephthalate film, which is around 1.4, making it possible to reduce the weight of the diaphragm, resulting in excellent playback characteristics in response to drive input. You can get a good speaker. Moreover, the film has excellent heat resistance and is self-extinguishing even when the temperature of continuous use is around 170°C.

Therefore, a diaphragm made of this film is ideal for applications that require heat resistance and flame resistance, such as for use in in-vehicle speakers. Further, the film is amorphous and does not crystallize even if left in a high temperature atmosphere for a long time. (9) Even if the film is left in a high-temperature atmosphere for a long time, there is almost no dimensional change. Therefore, there are not only changes in appearance but also changes in various performances.Also, from the viewpoint of molding the diaphragm, it is amorphous and therefore difficult to mold compared to highly crystalline polyethylene terephthalate. It is easy and mass production is possible.

EXAMPLE A film having the following basic structure shown below was used as a film for forming a diaphragm.

The physical property value of the film having the above basic structure is that the specific gravity is 1.2.
7. The elastic modulus is 19,000 (9 fakes), and the loss is 0.11. The diaphragm was molded using a vacuum forming method to form a cone-shaped diaphragm with a diameter of 50 mm and a thickness of 50 μm. A speaker as shown in Fig. 1 was created using this diaphragm.

Even when this diaphragm was left at 150° C. for 2 hours, no deterioration in performance was observed. Table 1 shows the dimensional changes of the films of Examples and the polyethylene terephthalate films after being left at 150° C. for 1 hour.

Table 1, Table 4, Brief Description of Drawings FIG. 1 is a partial sectional view of a speaker using the diaphragm of the present invention.

1... Vibration plate 2... Edge 3... Center cap 4... Yoke 5... Magnet 6...
・Voice coil 7...Center ball 8...Bobbin Diagram 1 Procedural amendment (voluntary) April 1980 411 Commissioner of the Japan Patent Office 1, Indication of the case 1988 Patent Application No. 244765 2, Invention Name Diaphragm for Speakers 3, Relationship with the case of the person making the amendment Patent Applicant Address 1-2-2 Uchisaiwai-cho, Chiyoda-ku, Tokyo Column for detailed description of the invention in the specification.

5. Contents of the correction In the 8th line of page 4, before "Table 1", it should be noted that even if a diaphragm integrated with the center cap was made using this film, the same effect would have been achieved. ] Add.

Below 1-

Claims (1)

[Claims] A diaphragm for speakers characterized by being formed by molding a film whose main component is thermoplastic polyetherimide resin.