JPS6219036Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a speaker with an improved magnetic fluid insertion mechanism.

A conventional speaker of this type is shown in FIG. In the figure, 1 is a pole piece including a bottom plate, 2 is a magnet, 3 is a plate, 4 is a frame attached to a magnetic circuit composed of the above-mentioned pole piece 1, magnet 2, and plate, and 5 is a diaphragm that serves as a diaphragm. , 6 is a bobbin that transmits vibrations to the diaphragm 5.
7 is a voice coil provided outside the bobbin 6; 8 is a support member fixing the bobbin 6 and the plate 3; and the bobbin 6 and the frame 4; 9 is a magnetic fluid; this magnetic fluid 9 is attached to the pole piece. The bobbin 6 and the voice coil 7 are inserted between the bobbin 6 and the voice coil 7 in the gap between the bobbin 1 and the plate 3.

Next, the operation will be explained. Magnetic lines of force generated by energizing the voice coil 7 are transmitted to the bobbin 6 and radiate vibration sound from the diaphragm 5. Here, the support member 8 is provided with holes or the like so that it functions only as a stiffness, and the vibration sound is radiated through the diaphragm 5. On the other hand, since the voice coil 7 generates a large amount of heat, the input resistance of the voice coil 7 is increased by dissipating this heat from the pole piece 1 and the plate 3 via the magnetic fluid 9, which has high thermal conductivity and easily passes magnetic force. are doing. Furthermore, the rise in temperature of the voice coil 7 is small due to the heat dissipation effect described above, so the rise in impedance is also suppressed and power linearity is improved.

Since the conventional speaker is constructed as described above, the inside of the magnetic circuit made up of the pole piece 1, magnet 2, and plate is sealed, and the pressure caused by thermal expansion of the air in the circuit and volume change at large amplitudes is reduced. As a result, the magnetic fluid 9 is scattered. Furthermore, even if the magnetic fluid has a low vapor content, it is difficult to completely suppress evaporation over a long period of time, and as a result, the viscosity of the magnetic fluid increases, causing changes in the physical characteristics and sound quality of the unit, and the scattering of the magnetic fluid. There were drawbacks such as the inability to control damping, which determined the range of viscosity due to the risk of

This idea was made to eliminate the drawbacks of the conventional ones as mentioned above, and it consists of a diaphragm, a bobbin, and an edge integrated into a diaphragm.
To provide a speaker in which scattering and evaporation can be suppressed without impairing the function of the magnetic fluid and damping can be controlled by sealing the magnetic fluid accommodated in the gap recess between the bobbin and the plate with a support member. It is an object.

An embodiment of this invention will be described below with reference to the drawings. In FIG. 2, 21 is a pole piece including a bottom plate, 22 is a magnet, 23 is a plate, and 24 is a frame attached to a magnetic circuit composed of the above-mentioned pole piece 21, magnet 22, and plate 23. 25 is a diaphragm, and this diaphragm 25 has a diaphragm 25a,
The bobbin 25b and the edge 25c are integrated, and the end of the edge 25c is fixed to the lower surface of the plate 23. 26 is the diaphragm 2
Voice coil attached to the outer surface of the bobbin 5, 2
Reference numeral 7 denotes a magnetic fluid accommodated in a recessed space between the plate 23 and the bobbin 25b, and this fluid is adjacent to the voice coil 26. A support member 28 is attached to the plate 23 and closes the upper opening of the gap. Note that the support member 28 is attached to the frame 24 in FIG. 3 and closes the upper opening of the gap. Further, the inner end (right end) of the support member 28 is close to the outer side of the bobbin 25b of the diaphragm 25, and is not connected to the outer surface of the bobbin 25b in order to allow vibration in the direction of the winding axis of the voice coil 26. . However, like the edge 25c of the diaphragm 25, the inner end of the support member 28 may be configured to allow vibration in the direction of the winding axis of the voice coil 26, for example, the support member may be made thinner to have flexibility. The support member 28 may be formed into a corrugated shape and connected to the outer surface of the bobbin 25b, or the support member 28 may be formed integrally with the diaphragm.

Next, the operation of this invention will be explained. The magnetic force generated by energizing the voice coil 26 is applied to the bobbin 2.
5b and is emitted from the diaphragm 25a as vibration sound. On the other hand, the heat generated from the voice coil 26 is transmitted through the magnetic fluid 27, which has a high thermal conductivity, and is effectively radiated from the plate 23 (the magnetic fluid 27 has a conductivity six times that of air). Furthermore, if the material of the diaphragm 25 is a metal with high thermal conductivity, such as titanium, magnesium, aluminum, beryllium, etc., heat is also radiated from the diaphragm 25, so that the heat radiation effect of the voice coil 26 is further increased.

In the embodiment, a dome-shaped speaker has been described, but the same effect can be obtained with other hybrid-type or cone-shaped speakers.

As described above, according to this invention, a diaphragm, a bobbin, and an edge are integrated to constitute a diaphragm, and a magnetic fluid is accommodated in the recessed part of the gap between the bobbin and the plate, and this fluid is transferred to the support member. By closing the magnetic fluid and preventing it from coming into direct contact with air, evaporation reduction can be prevented for a long period of time, and the physical properties of the magnetic fluid, such as viscosity changes, will not change, and the quality of the unit will be stable. Another advantage is that even if the magnetic fluid itself is based on water, for example, it can be used. Furthermore, it is possible to prevent the magnetic fluid from scattering due to the pressure caused by the thermal expansion of the magnetic circuit and the volume change during large amplitudes, and it is not limited by the viscosity of the fluid, making it possible to control damping, etc., making it a high-performance speaker. There is an effect that can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the main part of a conventional speaker, and FIGS. 2 and 3 are sectional views of the main part of the speaker of this invention. 21...Pole piece, 22...Magnet,
23... plate, 24... frame, 25...
Vibration plate, 25a...diaphragm, 25b...bobbin, 25c...edge, 26...voice coil, 27...magnetic fluid, 28...support member. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] In a speaker in which a magnetic fluid is inserted into the gap between a pole piece and a plate, a diaphragm, a bobbin, and an edge are integrally molded into a diaphragm, and the plate and bobbin are formed by fixing the edge to the lower surface of the plate. A speaker characterized in that a magnetic fluid is accommodated in a recessed gap, and an upper opening of the gap is closed with a support member.