JPS62120197A - Production of edge for speaker - Google Patents

Abstract

PURPOSE:To prevent the generation of a non-linearity distortion by forming the raw material of an oil added polyurethane rubber into a sheet, molding into a thin cylindrical form by a vacuum molding method, folding back an intermediate part and making a linearity in a car displacement characteristic of a supporting system good. CONSTITUTION:The oil added polyurethane rubber raw material is formed into the sheet of a tack state, a B stage, what is called by a T die extrusion method. A polyurethane rubber elastic material is formed to a thin cylindrical shape rubber elastic material by the vacuum molding method. A post curing is applied to an edge 6 composed of the cylindrical shape rubber elastic material, the intermediate part is folded back, the circumference of one end of the cylinder is connected to a diaphragm 8 and the circumference of the other end is connected to a frame 7 or a fixed end. Thereby, the linearity in the car displacement characteristic of the supporting system is made good and the generation of the non-linearity distortion is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for producing a speaker edge by molding a sheet-like oil-extended polyurethane rubber oil body.

2. Description of the Related Art Typical conventional cone-shaped speakers have shapes such as those made of a highly elastic material such as polyurethane foam, which is flat, those with several concentric corrugations, and There are roll edges and the like that have one large curved surface.

(For example, Takeo Sanmizu, "Speaker System (Part 1)", 1985, Radio Gijutsusha, p. 143 to p. 147) The above-mentioned conventional speaker edge will be described below with reference to the drawings.

FIG. 2 shows a cross-sectional view of the vibration system and support system of a conventional speaker. In Figure 2, 1 is an edge, 2 is a frame for fixing the outer periphery of edge 1, and 3 is an edge 1.
4 is a vibration system such as a voice coil bobbin 6 whose tip is fixed to the diaphragm 3, a magnet, and a ball.

It consists of a magnetic circuit system (not shown) consisting of a plate and a yoke, and a support system for the edge 1. When an audio current flows through the voice coil 5 in a uniform magnetic field, a vertical force is generated in the voice coil 5, causing it to vibrate in accordance with the current. This vibration is properly transmitted to the vibration of the diaphragm 3 and radiated as a sound wave. The edge 1 also supports the diaphragm 3 and serves to keep the diaphragm 3 centered at all times.

Problems to be Solved by the Invention However, in the speaker edge described above, the linearity of the Kerr displacement characteristic of the support system is good to some extent in the range of small amplitude of the diaphragm, but when the amplitude of the diaphragm is large, contains nonlinearity and will generate distortion.

In addition, when the above-mentioned highly elastic polyurethane foam is used in a flat state, the foaming state is uneven and the thickness of the foam is not constant, so abnormal vibrations are likely to occur. Further, when corrugation processing or roll edge processing is performed using conventional materials such as foamed polyurethane, there is a drawback that deep drawing processing is impossible and the material may break.

In view of the above-mentioned problems, the present invention provides a method for manufacturing a speaker edge that has good linearity in the Kerr displacement characteristics of the support system and does not cause non-linear distortion even when the diaphragm has a large amplitude. It is something.

Means for Solving the Problems/Means to Solve the Problems In order to achieve this object, the speaker edge of the present invention is made by first processing a polyurethane rubber raw material to which oil has been added, which is a raw material, into a semi-cured state, so-called B stage state, by a T-die extrusion method. After producing the sheet, it is formed into a thin cylindrical shape using a vacuum forming method. The thin-walled cylindrical edge made of oil-extended polyurethane rubber elastic material is post-cured, and then folded back and placed around one end of the cylinder as a diaphragm and the other end. The periphery of the frame is connected to a frame or a fixed end.

Function: With this configuration, when the imaging plate vibrates, there is no unevenness in the material and film thickness, so abnormal vibrations do not occur, and the material is made of a viscoelastic material called polyurethane rubber. It is possible to eliminate even the slightest abnormal vibrations that occur, and since oil is added to the polyurethane rubber (oil extension),
Abnormal vibrations are further suppressed.

Furthermore, even when the diaphragm has a large amplitude, since the rubber-like elastic body is used, the folded edges of the edges can move freely and without tension. , it is possible to obtain a speaker with less nonlinear distortion compared to the conventional roll edge.

EXAMPLE An example of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing the structure of a speaker in an embodiment of the present invention. It consists of a support system and a vibration system consisting of an edge 6, a frame end, a diaphragm 8, a voice coil bobbin 9, and a voice coil 10, and a magnetic circuit system (not shown) consisting of a magnet, a pole, a plate, and a yoke. When a voice current flows through the Niallheuss coil 10 in a uniform magnetic field, a vertical force is generated in the voice coil 10, causing it to vibrate in accordance with the current. This vibration/force is properly transmitted to the vibration of the diaphragm 8 and radiated as a sound wave. Moreover, the edge 6 supports the diaphragm 8 and can always keep the diaphragm 8 in the center.

The edge 6 is manufactured as follows. A mixture of diisocyanate and polyol as raw materials with 5% (weight fraction) of silicone oil added as an oil extender was heated to a head temperature of 5o''C using a screw extruder.
1 die temperature 1150~6°C, die temperature 50~60
A sheet of semi-cured polyurethane rubber elastic material is molded at .degree.

The precision of the molded product is adjusted by extrusion speed, die temperature, and withdrawal speed, and the film thickness is set to 5 μmK.

Thereafter, the molded product is molded into a predetermined shape using a vacuum forming method, the molded product is removed from the mold, and the edge 6 is created by post-curing at 160'C for 30 minutes.

As described above, according to this embodiment, the edge 6, which is constructed by folding back the middle part of the molded product made of oil-extended polyurethane rubber elastic body, eliminates abnormal 1-slide motion during input, and On the other hand, while moving the turning point smoothly,
Due to the operating structure and the viscoelasticity of the material, linearity is good, and compared to speakers using conventional roll edges, the distortion rate can be reduced by about 20 d'B for a large input of 1 W at 100 Hz.

Effects of the Invention As described above, in the present invention, after producing a sheet in a semi-cured state, so-called B-stage state, from the raw material of oil-extended polyurethane rubber by T-die extrusion molding method,
A speaker edge formed into a thin cylindrical shape using a vacuum forming method.The middle part of this molded product is folded back, and one end of the cylinder is connected to the diaphragm, and the other end is connected to the frame. The speaker edge eliminates abnormal imaging during input, and also has a structure that moves while smoothly moving the turning point when the amplitude is large. A distortion rate speaker can be obtained.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a speaker in an embodiment of the present invention;
FIG. 2 is a sectional view of a conventional speaker. 6--- Edge, 7... Frame, 8...
・Diaphragm, 9 ・Voice coil bobbin, 10...
・Voice coil.

Claims (1)

[Claims] A semi-cured state (B stage state) sheet-shaped oil-extended polyurethane rubber elastic body formed by extrusion using a T-die was molded into a thin cylindrical rubber-like elastic body by vacuum forming. For a speaker, the intermediate part of the post-cured molded product is then folded back to create a structure in which one end of the cylinder is joined to a diaphragm and the other end is joined to a frame or a fixed end. Edge manufacturing method.