JPS6338637Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a flat speaker that drives a diaphragm through a driving cone.

Conventionally, there has been a flat speaker of this type as shown in FIG. In the figure, 1 is a circular flat diaphragm, 2 is an edge bonded to the outer periphery of the diaphragm 1, 3 is a driving cone having a cone shape and whose outer periphery end is bonded to the diaphragm 1; 4 is a voice coil bonded to the inner peripheral end of the driving cone 3 to drive the diaphragm 1 and the driving cone 3; 5 is a damper bonded to the voice coil 4 to support it; 6 is an edge 2 and A frame for fixing the damper 5, 7 a magnetic circuit for driving the voice coil 4, and 8 a hole drilled in the driving cone 3.

Generally, it is known that the reproduction frequency band of the flat speaker as described above can be expanded by node driving. In other words, by driving the nodes of the axially symmetrical first-order split vibration, the first-order split vibration mode is canceled, the sound pressure characteristics become flat, and the reproduction band is expanded to the second-order split vibration that occurs at about four times the frequency of the first-order split vibration. It is possible. There are two ways to drive a node of primary divided vibration: using a voice coil with the same diameter as that node, and using a voice coil with a smaller diameter than the node as in the conventional example shown in Figure 1 and driving it via a driving cone. This method is often used. The former method, which uses a voice coil with the same diameter as the node, inevitably requires a larger magnetic circuit and increases costs, so low-to-midrange speakers use the latter structure, which is about the same size as a cone-shaped speaker. A method of driving the device using a voice coil and a magnetic circuit is used.

In a speaker having such a conventional structure, a nearly hermetically sealed space is formed inside the driving cone 3 and the voice coil 4, which causes an increase in the bass frequency characteristic fo and the occurrence of distortion. As these improvement measures,
A method is used in which a hole is made in the bobbin of the voice coil 4 or the side surface of the driving cone 3, and the hole 8 shown in FIG. 1 is for this purpose. However, drilling the hole 8 in the driving cone 3 reduces the strength of the driving cone itself, and has the disadvantage that a step for drilling the hole is also required.

This idea was made in order to eliminate the drawbacks of the conventional ones as described above, and it was designed to create a speaker that can improve the bass characteristics by providing an air vent hole in the part of the driving cone that connects with the diaphragm. is intended to provide.

An embodiment of this invention will be described below with reference to FIG.

In the figure, 8 is a hole as an air vent opening, and this hole 8 is formed by molding at the upper end of the driving cone 3, that is, at the joint with the diaphragm 1. It has concave grooves in several places.

FIG. 3 is a top view of only the driving cone 3 of the embodiment of this invention shown in FIG.

By providing the hole 8 as described above, the structural strength of the hole itself, as well as the strength of the driving cone 3 itself, can be maintained, unlike the conventional method where the hole is simply punched. Moreover, it has the advantage that the hole for air venting can be easily formed by molding, so there is no need for the conventional hole-drilling process.

In the above embodiment, an explanation has been given of a device that has a circular diaphragm and drives a node of primary division vibration, but it is not limited to a circular shape, and can also be used when driving a node of a second order or higher order. Good too.

As described above, according to this invention, air vent holes are formed by molding in the part of the driving cone that joins with the diaphragm, so a structurally strong driving cone can be obtained, and it is also easy to manufacture. There is.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing a conventional flat speaker.
Figure 2 is a sectional view showing one embodiment of this invention;
The figure is a front view of the driving cone of FIG. 2. In the figure, 1 is a diaphragm, 2 is an edge, 3 is a driving cone, 4 is a voice coil, 5 is a damper, 6 is a frame, 7 is a magnetic circuit, and 8 is a hole. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims for Utility Model Registration] (1) In a flat speaker that drives a diaphragm through a driving cone, a plurality of air vent openings are formed from the upper end of the portion of the driving cone that connects with the diaphragm. A flat speaker characterized by: (2) The flat speaker according to claim 1, wherein the driving cone is formed by integrally molding metal foil.