JPS6334399Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a speaker in which the vibration of the voice coil bobbin is transmitted to the main diaphragm via the sub diaphragm and its edges, and the rolling of the main diaphragm, the sub diaphragm and the voice coil is reduced, The purpose of this is to reduce gap rubbing of the voice coil and at the same time prevent mechanical destruction of the edges of the sub-diaphragm (hereinafter referred to as sub-edges).

FIG. 1 shows a flat speaker equipped with a mechanical filter, and FIG. 2 shows a cone speaker equipped with a mechanical filter, both of which were previously proposed by the same applicant as the present application. In Figures 1 and 2, 1 is the main diaphragm, 2 is the edge of the main diaphragm,
3 is the frame, 4 is the second damper, 5 is the first damper, 6 is the A plate, 7 is the magnet, 8 is B
9 is a voice coil bobbin, 10 is a voice coil, 11 is a sub-diaphragm, and 12 is a sub-edge. Further, 13 in FIG. 2 is a lid that seals the upper end of the bobbin 9, and 14 is a dust cap.

Although the speakers shown in FIGS. 1 and 2 are different in shape, their operating principles are substantially the same, so the operation of only the planar speaker shown in FIG. 1 will be described below.

First, the force generated by the voice coil 10 causes the sub-diaphragm 11 to vibrate via the bobbin 9;
Compliance (springiness) of the air chamber surrounded by
Only the low-frequency component is transmitted to the main diaphragm 1 via the main diaphragm 1 and radiated to the outside world as a sound wave. At this time, the sub-edge 12 not only has the function of sealing the air chamber, but also supports the voice coil bobbin 9 together with the first damper 5, and has the role of firmly holding the bobbin 9 at its center to prevent it from rolling. For this reason, it is desirable to use thick urethane foam (for example, urethane foam resin hot-press molded to a thickness of about 1 mm) that has high sealing properties and center holding power for this sub-edge. However, such sub-edges made of urethane foam have the following drawbacks.

(1) Because the material is thick, the tensile stress applied to the bent edge portion is large when the edge is bent, and cracks are likely to occur on the surface of the bent edge portion. Therefore, there is a possibility that the edge will be destroyed during continuous large input.

(2) Foamed urethane edges have a strong center retention force, but are weak against tension, and do not cause instantaneous "tsuppari"
When this occurs, the bobbin tilts to one side due to variations in the extensibility of the edges in the circumferential direction, which tends to cause gap rubbing.

The present invention provides a speaker equipped with a sub-edge that overcomes these drawbacks.

FIG. 3a is a cross-sectional view of the roll portion of the urethane foam sub-edge 12. In order to provide center holding power, a foamed urethane sheet approximately 10 mm thick, which is thicker than ordinary Edge, is formed into a roll shape approximately 1 mm thick by hot pressure molding. Now, when a large input is applied to this sub-edge 12, the sub-edge 12 is displaced as shown in FIG.

Therefore, as shown in an embodiment shown in FIG. 4, if a cloth 17 is bonded and molded to the underside of the urethane sheet 16, even if the urethane sheet 16 should crack, the cloth 17 will prevent it from breaking. You can get away with it. Also, as shown in Fig. 5, the urethane sheet 16
By gluing cloth 17 on both sides of the material, it is possible to prevent destruction even more completely.As a sub-edge, it combines the center holding ability of urethane with the good bending resistance and tensile resistance of cloth. can obtain almost ideal properties. This property cannot be obtained with only a urethane sheet or only with cloth, and can only be achieved by pressurizing and adhering both at the same time during molding.

It goes without saying that not only urethane but also other foamed resins having the same effect may be used.

As described above, the present invention includes a sub-diaphragm that is directly driven by the voice coil bobbin, and a main diaphragm that is coupled to the sub-diaphragm via a sub-edge and driven indirectly via the sub-edge. The sub-diaphragm, the sub-edge, and the main diaphragm or dust cap constitute an air chamber, and the sub-edge is made of an elastic sheet made of foamed resin or the like with cloth attached to one or both sides. Therefore, a speaker without rolling can be constructed by using the sub-edges which have a large center holding force and excellent bending resistance and tensile resistance.

[Brief explanation of the drawing]

Figures 1 and 2 are cross-sectional views of a speaker with a mechanical filter, Figures 3a and b are cross-sectional views showing sub-edges of a conventional speaker, and Figures 4 and 5 are cross-sectional views of sub-edges used in the speaker of the present invention. FIG. 1... Main diaphragm, 2... Edge, 3... Frame, 4... Second damper, 5... First damper,
6...A plate, 7...Magnet, 8...B
Plate, 9...Voice coil bobbin, 10...
Voice coil, 11...Sub-diaphragm, 12...Sub-edge, 16...Urethane foam sheet, 17...
cloth.

Claims (1)

[Scope of utility model registration request] a sub-diaphragm directly driven by a voice coil bobbin; a main diaphragm coupled to the sub-diaphragm via a sub-edge and driven indirectly via the sub-edge; and a main diaphragm or a dust cap to constitute an air chamber, and the sub-edge is made of an elastic sheet made of foamed resin or the like with cloth attached to one or both sides.