JPS63278496A - Electrodynamic type speaker - Google Patents

Abstract

PURPOSE:To realize the saving of a space and the thin shape of a device, by joining a magnet on a plate with a poll piece, and arranging bisectedly the magnet of a speaker on whose other plane a top plate is joined. CONSTITUTION:Divided magnets 10 and 11, the top plate 1, and the plate 3 with the poll piece are provided, and in other words, it is constituted in such a way that the magnet is bisected, and they are arranged on both sides of the poll piece 3. Since it is possible to choose a ratio of a major axis to a minor axis freely in a magnetic circuit having such constitution, the major axis and the minor axis of the magnetic circuit suitable for the shape of a diaphragm can be set, and a structure where the magnetic circuit is covered with the diaphragm can be obtained. In such a way, it is possible to increase a degree of freedom in the design of the shape of the magnetic circuit, and to obtain the optimum magnetic circuit suitable for the diaphragm whose shape is being diversified for the saving of the space and for thin shape forming of the speaker.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electrodynamic speaker having a diaphragm shape other than a perfect circle, such as an ellipse or a rectangle, which aims to save space and reduce the thickness.

2. Description of the Related Art A general conventional external magnetic type electrodynamic speaker has a structure as shown in FIG. That is, a donut-shaped magnet 1-2 is bonded to the pole piece attached plate 1, and a top plate 3 is bonded to the surface of the magnet opposite to the surface bonded to the magnet 1. A pois coil 60 wire 6' connected to the center of a damper 6 whose periphery is fixed to a frame 4 is arranged in a magnetic gap G formed by a pole piece and a top plate so as not to touch the gear knob. The center portion of the diaphragm 7 is joined to the voice coil, and the outer periphery of the diaphragm 7 is joined to the frame via an edge 8. Furthermore, there is a dust cap 9 near the center of 7 to prevent dust from entering the magnetic gap.
are joined.

Next, regarding the operation of the speaker, when a source current flows through the voice coil wire 6', the wire receives a force from the magnetic flux of the magnetic gap and performs reciprocating motion in the direction of the arrow in the figure. The diaphragm 7 connected to the voice coil moves accordingly, vibrating the air in front of the diaphragm and generating sound. This is the structure and operation of a general electrodynamic speaker.

In recent years, many diaphragms have been made oval or rectangular in order to save space, but they are also becoming thinner in order to save space. Figure 4 shows a design in which the diaphragm has a convex shape to achieve a thin design, and the magnetic circuit is wrapped around the diaphragm, with the aim of saving space.The magnetic circuit is equipped with a donut-shaped magnet. This is an example in use. With this structure, the speaker can be made thinner than before by the "mu" dimension in the figure, but this is because the magnetic circuit is hidden by the concave surface of the diaphragm in the height direction when the speaker is at its maximum amplitude. It means the dimensions of

Problems to be Solved by the Invention The space-saving thin speaker with such a configuration has the following problems: - When applied to a speaker with an elliptical or rectangular dynamic plate, it has a unique structure in which the magnetic circuit is wrapped around the diaphragm. ,
If the outer periphery of the magnet protrudes beyond the outer periphery of the diaphragm, thinning cannot be achieved. This means that when a round magnet is used, the magnet diameter is limited by the short diameter of the diaphragm, reducing the degree of freedom in designing a high-performance, high-efficiency, broadband, etc. speaker.

The present invention solves this problem and provides an electrodynamic speaker that can increase the degree of freedom in speaker design.

Means for Solving the Problems The present invention has a structure in which the magnet is divided into two parts and placed on both sides of the pole piece.

The ratio of the long axis and short axis of the magnetic circuit with the main structure can be freely selected, so the long axis and short axis of the magnetic circuit can be set to match the shape of the diaphragm. can be realized.

Embodiment FIG. 1 is a perspective view of a first embodiment of the present invention, which is a magnetic circuit for an elliptical speaker. In the figure, 10° and 11 are divided magnets, 1 is a top plate, and 3 is a plate with a pole piece.

FIG. 2 is a perspective view of a second embodiment of the present invention, showing a magnetic circuit for a rectangular speaker.

Generally, in order to obtain high efficiency while maintaining a thin structure, it is appropriate to make the ratio of the major axis to the minor axis of the magnetic circuit approximately equal to that of the diaphragm. One possible way to achieve this is to make the magnet shape elliptical, rectangular, etc., and create a modified donut-shaped magnet with a through hole near the center, but this method would reduce the diameter of the voice coil used. If the width exceeds the width of the short axis of the magnet, the size of the short axis and the center hole will be approximately the same, making it difficult to handle the problem from the viewpoint of magnet manufacturing and magnet strength.

This embodiment increases the degree of freedom in designing the shape of the magnetic circuit, and can provide an optimal magnetic circuit for making the speaker thinner, in accordance with the shape of the diaphragm that is becoming increasingly used for space saving.

Above and beyond the effects of the invention, it can be said that the present invention is a useful and highly effective invention as space-saving and thinner products are expected to progress in the future.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 respectively show the first embodiment of the present invention. A perspective view of the second embodiment, FIG. 3 is a half-sectional view of a general conventional external magnetic type electrodynamic speaker, and FIG. 4 is a half-sectional view of a thin speaker. 1... Freight with pole piece, 3...
・Top plate, 10.11...Divided magnet.

Claims (1)

[Claims] In an external magnetic type electrodynamic speaker comprising a magnet bonded to a plate with a pole piece, a top plate bonded to the other side of the magnet, and a magnetic gap formed between the pole piece and the top plate, the above magnet An electrodynamic speaker characterized by being arranged in two parts.