JPS626789Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a dustproof cap for a speaker that is attached to the center of a diaphragm.

Conventionally, as shown in FIG. 1, a speaker having a truncated conical diaphragm forms a magnetic circuit with a center pole 6, a magnet 7, and a plate 8, and forms a magnetic gap with the center pole 6 and plate 8.
The bottom surface of the frame 9 is welded to the top surface of the plate 8, and the voice coil bobbin 5, which is placed at the center of the magnetic gap, has a damper 10 whose outer periphery is attached to the inner bottom of the frame 9.
A frusto-conical diaphragm 4 is held at the center of the magnetic gap by
The outer periphery of the diaphragm 4 is attached to the outer periphery of the frame 9.
There is a dustproof cap 11 in the lower center of the inside for dustproofing.
was attached. This dustproof cap 11 is obtained by molding a breathable material such as cloth or felt or a non-breathable material such as paper, metal, or film.
As shown in Figure 4 line a, breathable ones can enhance the bass range, but they are weak in strength and cannot be expected to have the effect of reinforcing the center of the diaphragm 4, and the frequency response will be distorted in the treble range. There are drawbacks. Non-ventilated caps are strong and have the effect of reinforcing the center of the diaphragm 4, as shown by line b in Figure 4, but the air sealed by the dustproof cap 11 does not affect the vibration of the diaphragm 4. Therefore, there is a drawback that the magnetic flux flows through the narrow magnetic gap and exerts a braking force due to the braking resistance, which adversely affects the vibration mode of the diaphragm 4. For this purpose, as shown in FIG. 2, a ventilation hole 13 is bored in the center of a dustproof cap 12 made of non-porous paper, and a breathable dustproof cloth 14 is used to close the ventilation hole 13.
There is a dustproof cap that can be attached to remove the above drawbacks and obtain both effects. The above-mentioned dustproof cap has the effect of preventing dust and reinforcing the diaphragm, and since air flows through the dustproof cloth 14, it suppresses the occurrence of braking resistance, and the sound pressure is high in the low frequency range, as shown in line c in Figure 5. In the treble range, good characteristics with no flaws in frequency characteristics can be obtained.

However, the above-mentioned dustproof cap has holes or
It requires a lot of effort to attach the dust-proof cloth 14, which has the disadvantage of being expensive.

The present invention was devised to eliminate the above-mentioned drawbacks, and if the embodiment shown in the drawings is explained, it will be explained as follows.
As shown in the figure, there is a voice coil bobbin 5 in the center.
A dust-proof cap 1 made of natural fiber or synthetic fiber is attached to the inner lower center of the frusto-conical diaphragm 4 that hangs down so as to close the upper end opening of the voice coil bobbin 5. This is a dustproof cap for a speaker, which is made thinner than Part 3 and has breathability.

Since the present invention has the above structure,
The outer peripheral part 3 has the effect of preventing dust and reinforcing the diaphragm, and since air flows through one or more parts 2, it suppresses the occurrence of braking resistance and improves the low frequency range as shown in line d in Figure 5. It has a high sound pressure and good frequency characteristics in the high frequency range, and can be made at the same cost as a conventional dustproof cap without separation.

As described above, the present invention is an industrially useful invention that provides a low-cost, high-performance dustproof cap.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a speaker, Fig. 2 is a sectional view of a conventional dustproof cap, Fig. 3 is a sectional view of the dustproof cap of the present invention, Fig. 4 is a characteristic diagram of a conventional speaker, and Fig. 5 is a sectional view of a conventional dustproof cap. Comparison diagram of characteristics when using the devised dustproof cap. 1 is a dust-proof cap, 2 is a partial portion or multiple portions, 3 is an outer peripheral portion, 4 is a diaphragm, and 5 is a voice coil bobbin.

Claims (1)

[Scope of utility model registration request] A dust-proof cap 1 made of natural fiber or synthetic fiber is attached to the inner lower center of the frusto-conical diaphragm 4 from which the voice coil bobbin 5 hangs, so as to close the upper end opening of the voice coil bobbin 5. Alternatively, a dustproof cap for a speaker is characterized in that a plurality of portions 2 are made thinner than the outer peripheral portion 3 to provide ventilation.