JPS5953756B2 - Ribbon-type speaker diaphragm support mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a support mechanism for a diaphragm of a ribbon-type speaker, which is a type of electrodynamic speaker.

Conventionally, there are the following two methods for supporting the diaphragm of a ribbon type speaker.

First, as shown in Figs. 1 and 2, the first method is to move the ribbon-shaped diaphragm 8' in the longitudinal direction (direction in which current flows).
Rolled or corrugated edges 8' on both ends of the
a, s'b are formed, and the edges 8'a and 8'b are fixed to the frame 7' using a holding plate or, for example, a known thermosetting adhesive, and the electric current of the diaphragm 8' flows. Play to form a magnetic circuit 1 with both sides of the direction) 4A
, 4B with a gap between them) 4A, 4
There was one in which a diaphragm 8' was disposed within the gear 5 between B.

In a second method, as shown in FIGS. 3 and 4, the periphery of the diaphragm 8'' is fixed within the gear 5 using, for example, a known thermosetting adhesive 9''.

However, the former one plays with both sides of the longitudinal direction of the diaphragm 8') depending on the method of the gap between 4A and 4B, the dimensions of the diaphragm 8' and the wavelength of the sound waves in the used band. If the limit is limited or a gap is formed around the diaphragm 8', especially between the two longitudinal sides of the diaphragm 8' and the playback plates 4A and 4B, the diaphragm 8' will resonate and its characteristics will deteriorate. There was a drawback that it disturbed the

In addition, the latter has fewer drawbacks like the former, but the compliance of the vibration system becomes smaller, and the lowest limit frequency characteristic f
There were drawbacks such as a decrease in efficiency due to the increase in O content and the addition of mass.

The present invention has been made in view of the above-mentioned points, and its purpose is to increase the compliance of the vibration system such as the diaphragm and edge, and to improve the vibration of a ribbon-type speaker in which resonance of the diaphragm is less likely to occur. The purpose is to provide a plate support mechanism.

The present invention will be explained below with reference to FIGS. 5 to 7.

1 is a magnetic circuit, and this magnetic circuit 1 is an example of a yoke 2.
The figure shows an external magnet type in which magnets) 3A and 3B are fixed facing each other on the upper surface, and magnets) 4A and 4B are fixed oppositely to the upper surface of magnets) 3A and 3B through a gap 5. .

Reference numeral 6 denotes an edge formed opposite to the frame 7 located inside the plates 4A and 4B and, if necessary, in the longitudinal direction (direction of current flow) of the diaphragm 8 described later. It may be flat, as shown in FIG. 7, or it may be corrugated, as shown in FIG.

Edges 5 and 6 are made of materials with high internal loss, such as cloth impregnated with resin and heat molded, rubber molded, plastic sheet heat molded, and foamed plastic sheet heat molded. is used.

Reference numeral 8 denotes a ribbon-shaped diaphragm, and this diaphragm 8 is made of aluminum in order to allow current to flow in a direction perpendicular to the passing magnetic flux flowing into the cap 5 from the plates 1 to 4A forming the magnetic circuit 1, that is, in the longitudinal direction. The diaphragm may be formed using a light conductive material such as foil, aluminum foil, etc., or if it is formed from a film made of an insulating material such as plastics, the electric current can be transferred to the diaphragm by printing aluminum foil, etc. 8 may be adjusted in the longitudinal direction.

To attach the diaphragm 8 to the edge 6, the diaphragm 8 is adhered to the edge 6 using an adhesive 9 with high viscoelasticity.

In this case, the adhesive having viscoelasticity is one in which a rubber-based polymer such as natural rubber or polyisobutylene is blended with a viscoelasticity imparting agent such as rosin, coumaron resin, oil-soluble phenol resin, or plasticizer. .

One embodiment of the present invention has the above-described configuration, and the diaphragm 8
A highly viscoelastic adhesive 9 is used on separate edges 6.6 formed opposite to the frame 7 located inside the plays 1-4A and 4B of the magnetic circuit 1 and in the longitudinal direction of the diaphragm 8. The edges of each are glued together.

In this case, the viscoelastic adhesive is, for example, natural rubber,
Rosin, coumaron resin, oil-soluble phenol resin,
A compound containing a plasticizer or the like is used.

Therefore, as shown in FIG. 3, directly on plates 4A and 4B,
In the conventional support method using adhesive 9'', the adhesive 9'' itself has to vibrate by the same amplitude as the vibration plate 8'', and the isometric compliance is very small. As a result, the low frequency reproduction limit frequency becomes higher, and if the diaphragm is bonded using edges, the edges themselves must be made of a stretchy material, which reduces the strength to support the diaphragm. On the other hand, if the edges are formed with a material that has strength, there will be no elongation, and resonance will easily occur, resulting in sharp peak dips due to frequency characteristics.In contrast, in the present invention, the diaphragm 8 is played separately) 4A, 4B and the edges 6 provided opposite to each other on the inside of the frame 7 are bonded using a highly viscoelastic adhesive 9 as described above, and the mass of the adhesive 9 is supported by the edges 6 and directly, Since the vibration plate 8 is not applied to the vibration plate 8, the adhesive strength of the adhesive is not reduced, and the amplitude of the adhesive (spread in the lateral direction) is extremely small compared to the amplitude of the edge 6, so the vibration system as a whole has a large There will be compliance.

Therefore, the edge 6 vibrates following the movement of the diaphragm 8, and the low limit frequency of the speaker can be lowered.

Furthermore, unlike the conventional method shown in FIG. Since the adhesive 9 is bonded using a high-quality adhesive 9, resonance of the diaphragm 8 can be prevented.

As described above, the present invention can increase the compliance of the vibration system including the diaphragm, the edge, etc., and therefore can lower the low frequency reproduction limit frequency.

In addition, by using a highly viscoelastic adhesive to adhere the edges of the diaphragm to the edges provided opposite to the inner edge of the magnetic circuit plate and the inner edge of the frame, two longitudinal sides of the diaphragm are connected to the plate. Since the gap can be eliminated, resonance of the diaphragm can be prevented and good reproduction can be achieved.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing the first method of supporting the diaphragm of a conventional ribbon-type speaker, Fig. 2 is a perspective view of the same, and Fig. 3 is a second method of supporting the diaphragm of a conventional ribbon-type speaker.
FIG. 4 is an explanatory sectional view showing the vibration state of the diaphragm, and FIG. 5 is a sectional view showing an embodiment of the diaphragm support mechanism of the ribbon-type speaker of the present invention. ,
FIG. 6 is an explanatory cross-sectional view showing the vibration state of the diaphragm, and FIG. 7 is a cross-sectional view showing a modification of the present invention. 1...Magnetic circuit, 4A, 4B...Plate, 5...Gap, 6...Edge, 7...Frame, 8... ...diaphragm, 9
······glue.

Claims (1)

[Claims] 1 At least an edge is provided inside each of the opposing plates of the magnetic circuit, and a ribbon-shaped diaphragm is adhered to the edge using a adhesive having viscoelasticity, and both ends of the diaphragm in the direction in which the current flows A diaphragm support mechanism for a ribbon-type speaker, characterized in that the diaphragm is placed within a gap by fixing the diaphragm to the frame.