JPS5838708Y2 - edge for speaker - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of the edge, which is a diaphragm support member of a speaker.

Conventionally, heat-molded synthetic resin films have been used as materials for speaker edges in consideration of mass production.

Polyethylene terephthalate and polycarbonate films are often used as film materials of this type.

However, with such conventional speaker edges made of materials, there is a problem in that the mechanical properties of the materials change with respect to temperature.

For example, Joule heat generated in the voice coil is transmitted to the edge portion via the coil bobbin, diaphragm, magnetic circuit, and frame.

If the diaphragm is made of pulp fiber or synthetic resin, the amount of heat transferred to the edges is not so much of a problem, but in speakers where the diaphragm is made of metal, the effect of Joule heat from the voice coil is It becomes impossible to ignore.

In particular, in a horn-type speaker using a metal Baum-shaped diaphragm 1 shown in FIG.
This effect is magnified due to the close distance between the two.

Under these conditions, polyethylene terephthalate has a Young's modulus of 4.3X10'kg/Cm2 at room temperature.
On the other hand, in the range of 140℃, it is about 0.8
Decreases to X 104kg/cm2.

Also, polycarbonate is approximately 2.1 x 10'kg/c
m2 to approximately 1.1 x 10'kg/cm2.

Therefore, such a change in the puffer ratio causes a change in the lowest resonance frequency, high frequency reproduction limit frequency, etc. in the frequency characteristics of the speaker.

This change in Young's modulus, on the other hand, causes creep elongation, leading to contact between the coil bobbin, the voice coil, and the magnetic circuit, which causes abnormal noise, voice coil burnout, and the like.

Therefore, this invention solves the above-mentioned drawbacks of the conventional example by heat-forming an aromatic polysulfone resin film whose Young's modulus changes little with temperature and using it for the edge. An example using a certain polyether sulfon resin film will be described in more detail.

Polyethersa and Rufuon resins are synthetic resins represented by the following structural formula, and are molded into a film through primary processing.

As shown in Figure 2, the polyether sulfone resin (■) has a Young's modulus of approximately 2. OX104kg/c
m2 is lower than that of polyethylene terephthalate (■) and approximately the same as that of polycarbonate (■), but at 140°C, polyethylene terephthalate (0°8 x 104 kg
/cm2) Polycarbonate (1, I x 10'kg
/cm2) compared to 1.8 x 10'kg/cm2
It has a large value, and the change from the value at room temperature is extremely small.

Polysulfone resin, which is a type of aromatic polysulfone resin, also shows a similar tendency.

It also has excellent properties, with elongation in an atmosphere of 150° C. being less than 1% in one year.

Therefore, if the film is used as an edge,
Deterioration and elongation of the mechanical strength of the voice coil due to Joule heat are extremely small, and therefore the designed frequency characteristics can be maintained.

Further, since vacuum forming and the like are extremely easy as secondary processing, it has the advantage that a desired corrugation can be formed and a compliance value can be arbitrarily set.

In addition, in this embodiment, it is also possible to control internal loss by overlapping another film (for example, a polypropylene film) as necessary.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a horn-type speaker, and FIG. 2 is a diagram showing the temperature characteristics of the edge of this invention and the conventional edge.

Claims (1)

[Scope of utility model registration request] A speaker edge made by heat molding an aromatic polysulfone resin film.