JPS58106997A - Dynamic speaker - Google Patents

Abstract

PURPOSE:To improve the nonlinear distortion generated by the deformation or the like of a diaphragm and facilitate winding a voice coil without reguiring a special wire rod, by selecting the voice coil so that the thickness of the voice coil becomes thinner according as going toward the outside of the coil. CONSTITUTION:What is called a flat type conductor is used as a wire rod of a voice coil 4. In this case, the conductor is so selected that the thickness of the coil 4, namely, the length in the direction of an axial line 3a of a coil bobbin 3 becomes shorter according as going toward end parts of the coil bobbin 3. Since the coil 4 is so formed that the thickness of the coil 4 is thinner toward the outside of the coil 4, the current density is low in the center part and is higher toward the outside in the direction of the axial line 3a of the bobbin 3. Consequently, the generation of the distortion due to nonlinearity is avoided approximately. Further, the coil 4 is produced very easily, and the coil 4 is wound closely in parts of adjacent turns.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a voice coil for a dynamic speaker. In a dynamic speaker, it is desirable that the diaphragm dominate (vibrate) depending on the magnitude of the current supplied to the voice coil. However, this deflection of the diaphragm is not necessarily proportional to the magnitude of the current flowing through the voice coil.

In other words, when a large current is supplied to the coil and the diaphragm vibrates greatly, its deflection approaches saturation and begins to exhibit nonlinearity. This is because it is supported by the system, and also due to deformation of the diaphragm itself. It also depends on the non-uniformity of the magnetic field distribution within the magnetic gap in which the voice coil is placed. This non-linearity of the vibration of the diaphragm has the drawback of producing particularly third-order harmonic distortion.

In order to avoid such drawbacks, a configuration shown in FIG. 1 has been conventionally considered. To explain the figures, (1) is a center ball, (2) is an annular plate, and a magnetic gap is formed between them. (3) is a coil bobbin disposed within this magnetic gap, and (4) is a voice coil wound around this. (5) indicates a diaphragm. Then, the voice coil (4) is wound roughly in the center of the winding portion of the coil (4) with respect to the direction of the axis (3a) of the coil bobbin (3), as shown in FIG. It should be wrapped more closely as it goes towards the
In this case, the wire of the voice coil (4) may have the same cross section over its entire length.

It is well known that by winding the voice coil (4) more densely at both ends than at the center, the distortion caused by the nonlinearity described above can be largely avoided. . However, this 5 has a coil (
4) is extremely difficult to wrap, and maintaining this state over a long period of time is not reliable. Furthermore, it becomes difficult to wind the coil (4) in 21 or 3 layers.

In the example shown in FIG. 2, the cross-sectional area of the wire at the center of the coil bobbin (3) is increased in the direction of extension of the axis (3a) of the coil bobbin (3), and the cross-sectional area of the wire decreases toward the outside. Since the current density is substantially higher on the outside than in the central part of K, the same objective as in the case of FIG. 1 can be achieved. However, this example has the disadvantage that it is difficult to manufacture and impractical because the diameter of the wire needs to be different at both ends and the center of the coil.

The present invention is designed to easily achieve the above object while avoiding the drawbacks shown in FIG. 1 and FIG. 2, and will be described below with reference to FIG. In this figure, parts corresponding to those in FIGS. 1 and 2 are marked with a 4- symbol, and their explanation will be omitted.

In the present invention, the third wire is used as the wire material of the voice coil (4).
As shown in the figure, a so-called rectangular conductor is used. And in this case, the thickness of the coil (4)! 1J The length of the coil bobbin (3) in the direction of the shaft leg (3a),
The coil bobbin (3) is selected so that it becomes thinner toward the end.

Such a coil (4) can be easily made by the following method. That is, a conventionally known conductor with a circular cross section as shown in FIG. Make a wire with a small thickness. At this time, by gradually weakening the pressure of the pair of pressure rollers, a layer having a relatively large thickness as shown in FIG. 4CK is formed, and as the pressure of the pair of rollers is further increased, It is also possible to create a thinner section as shown in FIG. 4B.

That is, in the present invention, when a circular wire as shown in FIG. 4 is prepared and the wire is passed through a pair of pressure rollers, the pressure is adjusted appropriately. Therefore, the coil (4) shown in FIG. It is possible to obtain continuously. Therefore, the cross-sectional area of this coil (4) is the same for each part.

According to the dynamic speaker according to the present invention described above,
Since the thickness of the coil (4) is smaller toward the outside of the coil (4), the axis (3a) of the bobbin (3)
Regarding the direction, the current density is small near the center and gradually increases toward the outside.

Therefore, the same objectives as explained in FIGS. 1 and 2 can be achieved. Moreover, according to the present invention, the coil (4)
It is very easy to manufacture the coils, and as is clear from the drawings, the adjacent parts of each coil can be wound closely together, so there is no problem as explained in Fig. 1. There is no risk of stability.

As explained above, according to the Guinatx speaker according to the present invention, non-linear distortion caused by deformation of the diaphragm etc. is improved, winding is easy without the need for special wire, and the voice The space utilization efficiency as a coil is high, the efficiency of the speaker is improved, and since it can be tightly wound, it has the characteristics of high mechanical strength.

[Brief explanation of drawings]

1 and 2 are enlarged sectional views of a part of a conventional dynamic speaker, FIG. 3 is an enlarged sectional view of a part of a dynamic speaker according to the present invention, and 4th figure is a sectional view of a wire rod for explaining the manufacturing process. . (1) is center ball, (2) is circular play), (
3) is a coil bobbin, (4) is a voice coil, (5)
is a diaphragm. Figure 1 Figure 4

Claims (1)

[Claims] A dynamic speaker comprising a rectangular conductor voice coil wound around a coil bobbin, characterized in that the thickness of the voice coil in the axial direction of the coil bobbin is selected to become thinner toward the end of the coil bobbin. dynamic speaker.