JPS58107800A - Rectangular flat plate diaphragm - Google Patents

Abstract

PURPOSE:To improve the efficiency and the high frequency reproduction frequency characteristics, by forming a core of a diaphragm into a construction having radial rugged grooves and providing a surface member on both sides. CONSTITUTION:The core member 4 of a rectangular flat diaphragm is formed into a construction of a thermoplastic resin film having radial rugged grooves 4, 4' by press forming, vacuum forming or pressure forming. After the forming, a surface member 5 made of a light metal foil or high polymer film having a comparatively high elasticity is sticked on both sides of the core member 4. Thus, the longitudinal and laterla strength of the diaphragm itself is improved and the sound pressure frequency characteristics flat up to high frequencies can be obtained, and since the shape of the core member is not appeared on the surface of the surface member at the bonding between the core member and the surface member, the productivity is increased to attain the diaphragm plate suitable for mass-production.

Description

Detailed Description of the Invention The present invention relates to a rectangular flat plate diaphragm for speakers, and its purpose is to provide a rectangular flat plate that is highly productive and capable of obtaining flat sound pressure frequency characteristics up to high frequencies. Our goal is to provide a diaphragm.

In general, most speaker diaphragms are made of paper pulp, and the diaphragm has a cone shape. However, speakers using these imaging plates have the disadvantage that it is difficult to obtain flat sound pressure frequency characteristics because the sound source position is shifted between the inner and outer peripheries of the imaging plate. Ta.

Therefore, in contrast to the above-mentioned speakers, flat-plate speakers, in which the diaphragm is flat and the sound sources are aligned, have recently been developed from the perspective of flattening the sound pressure frequency characteristics. Since the mounting area for such speakers is limited, rectangular flat speakers have begun to be developed in order to make effective use of the limited space in equipment and expand the vibration area.

In the case of these flat diaphragms, if the diaphragm is simply made into a flat diaphragm, the rigidity against bending is low and split vibration is likely to occur, making it impossible to obtain flat sound pressure frequency characteristics over a wide band. As a means to solve these problems, polystyrene foam and plastic foam were used as the core material 1, as shown in FIG.

Furthermore, a rectangular flat plate diaphragm is used in which surface material 2 such as aluminum foil is adhered to both surfaces of the core material 1.

However, in the case of a diaphragm using a foam as the core material 1 itself, although it has the advantage of being relatively low in cost and having good productivity, there is a problem in that the diaphragm itself is heavy. Particularly, in the case of a small flat diaphragm, the thickness of the core material must be reduced, and the foam must be cut using a hot wire or the like. In such a case, the cut surface of the foam will shrink due to heat during cutting.

This resulted in a decrease in foaming ratio, an increase in weight, and a decrease in efficiency. Therefore,
As shown in Figure 2, it is conceivable to use a flat diaphragm whose core material is a conventional aluminum nicum structure that provides high bending rigidity, but since the processing process for these diaphragms is complicated, In addition to the disadvantages of high production costs, when attempting to reduce weight by reducing the foil thickness of one surface material when bonding the core material and surface material, it is difficult to bond by heat press i. Creates sealed irregularities within the core shape,
As a result, the shape of the core is exposed on the surface material due to air contraction after the surface material is bonded.

This had the disadvantage that the shape of the core material was visible on the surface of the surface material.

The present invention solves the problems of the conventional rectangular flat diaphragm, and the core of the rectangular flat diaphragm has a radially uneven shape.

With this configuration, it is possible to improve the longitudinal and lateral strength of the rectangular flat plate diaphragm itself, and obtain flat sound pressure frequency characteristics up to high frequencies. In addition, since the shape of the heartwood does not appear on the surface of the surface material,
It is possible to improve productivity and provide a rectangular flat diaphragm suitable for mass production. In other words, when bonding the core material and the surface material by heat pressing, etc., there is no sealed unevenness within the shape of the core material, so the shape of the unevenness may be formed on the surface material by air contraction after the surface material is bonded. can be eliminated and productivity can be increased. j Below, the rectangular flat plate diaphragm of the present invention will be explained with reference to the drawings.

Fig. 3 shows an embodiment of the rectangular flat plate diaphragm of the present invention, and in Fig. 3, the core material 4 is formed by press forming, vacuum forming, pressure forming, etc. as shown in Fig. 4. It is a flat plate-like structure in which a thermoplastic resin film is molded into a structure having radially uneven shapes 4', 4', and FIG. 6 is a perspective view of the core shape as seen from the direction A.

After the core material 4 is formed by molding in this way, a surface material 6 made of a light metal foil or polymer film having relatively high elasticity is pasted on both sides of the core material 4, which has radially uneven surfaces, as shown in FIG. It is attached.

The rectangular flat plate diaphragm constructed in this manner can be manufactured by a process of adhering the surface material 6 to both sides of the core material 40 formed from a film by heat pressing, etc., so it has the advantage of high productivity and relatively low cost. are doing. Since the uneven grooves in the core material 4 extend radially from the center and are all passed through to the outside, there is an advantage that the shape of the core material 4 does not easily come out on the surface of the surface material 6 when the surface material 5 is bonded. This reduces the foil thickness of the surface material 6,
It becomes possible to reduce the weight. In addition, in terms of characteristics, as shown in Figure 6 a and b, the vertical bending strength and the lateral bending strength are the same, and the strength is the same as that of the conventional honeycomb shape. By being able to do this, as shown in FIG. 9, it is possible to improve efficiency and high frequency reproduction characteristics. 9th
In the figure, curve 1, curve 2, is the sound pressure frequency characteristic of the speaker using the rectangular flat plate diaphragm of this embodiment, and curve E is the sound pressure frequency characteristic of the speaker, using the conventional rectangular flat plate diaphragm whose core material is polymer foam. It is.

Incidentally, the sound pressure frequency characteristics shown in FIG. 9 were evaluated by making prototype speakers as shown in FIGS. 7 and 8.

In FIGS. 7 and 8, reference numeral 6 denotes a rectangular flat plate diaphragm, the outer periphery of which is supported by a frame 8 via an edge member 7. Then, as shown in FIG. 8, Macnet 9. York 10. A magnetic circuit consisting of a center ball 11 is attached, and a voice coil bobbin 13 supported by a damper 12 is directly bonded to the frame 8 at the position of a node formed on the rectangular plane diaphragm 6.

10 and 11 show other embodiments of the rectangular flat plate diaphragm of the present invention, in which the core material 14 is a flat plate formed from a thermoplastic resin film into a structure having radially uneven shapes 14', 14'. The difference from the first embodiment is the voice coil bobbin bonding position (drive position,
This is because the center point of the radial uneven shape is located at the position of the node caused by the I-moving plate resonance frequency. Even if this core material 14 is used, similar effects such as improved efficiency and expansion of the reproduction band can be expected.Furthermore, by bringing the maximum strength of the core material above the drive position.

It is expected that reliability (input resistance) will be improved.

As described above, according to the present invention, the core material is formed into a structure using radially uneven grooves and the surface material is provided on both sides, so efficiency is high and high frequency reproduction characteristics can be improved. It has the advantage of being able to

[Brief explanation of the drawing]

Figures 1 and 2 are perspective views of a conventional rectangular flat diaphragm;
The figure is a perspective view showing an embodiment of the rectangular flat plate diaphragm of the present invention.
Figure 4 is a top view of the core material that makes up the diaphragm, Figure 6 is a perspective view of the core material that makes up the diaphragm, Figure 6 is an explanatory diagram of the bending strength of the diaphragm, and Figure 7 is a prototype speaker. (Node drive method)
The top view, Figure 8 is a sectional view of the same speaker, Figure 9 is a comparison curve diagram of the sound pressure frequency characteristics of a prototype speaker using the same diaphragm and that of a conventional speaker, and Figure 10 is a comparison curve of the sound pressure frequency characteristics of a prototype speaker using the same diaphragm. A top view of the core material used in another embodiment of the rectangular flat diaphragm of the invention, and FIG. 11 is a side view of the same diaphragm. 4.14...Heartwood% 4', 4', 14
', 14'... Concave and convex groove, 6... Surface material, 6... Rectangular flat plate diaphragm, 7... Edge member, 8... Frame , 9...Middle magnet, 1o...Yoke, 11...Center pole, 12...Dunbar, 13f...Voice coil bobbin. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 10 Figure 115! J

Claims (1)

[Scope of Claims] 1. A thermoplastic resin film is formed into a core material by press molding or the like to simultaneously improve the strength in the longitudinal and lateral directions. A rectangular flat plate diaphragm made by pasting surface materials such as light metal foil and polymer film with relatively high elasticity on both sides. 2. The center point of the radially uneven shape of the core material is generated by the co-optation frequency of the diaphragm itself. Claim 1: Feature 4, characterized in that the voice coil is provided at a voice coil drive position corresponding to the position of the node.
Rectangular flat plate diaphragm as described in section.