JPS6253600A - Diaphragm for speaker - Google Patents

Abstract

PURPOSE:To obtain a speaker, the sound pressure frequency characteristic of which is flat and highly efficient by providing recessed parts in the circumference direction of each apex of a vibration member in which plural almost polyhedral angle shapes or almost polyconic shapes, the opening ends of them being linked, has the function of a rib. CONSTITUTION:A diaphragm is formed with molding a thermoplastic resin or a thermosetting resin by a heating vacuum molding method and a heating press molding method. Setting a position where the density of a triangular pyramid connecting a trough line 3 and ridge lines 1 and 2 is made even at the inside and outside, that is, a position of about 70% of the diameter of the diaphragm as deepest, a recessed part 4 is provided at the apex of the triangular pyramid where the above portions are made continuously, and a stick agent is coated on the recessed part 4 in advance, joining a voice coil bobbin 5. Thus, a node circle on which the primary resonance of a circular plate is appeared is fixed on the voice coil bobbin 5, suppressing a dividing resonance. And the voice coil bobbin 5 is assembled in a magnetic circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a speaker diaphragm used in various types of audio equipment.

2. Description of the Related Art Conventionally, a cone-shaped diaphragm 6 as shown in FIG. 4, for example, has often been used as a diaphragm for a speaker. This is because the cone shape structurally has extremely high bending strength in the imaging direction, so a wide reproduction band can be easily obtained even with low elasticity materials such as paper and plastics, and the material is inexpensive.

As another conventional example, a planar diaphragm using a honeycomb sandwich inch structure as shown in FIG. 5 has been studied and put into practical use. That is, a honeycomb material 7 made of pulp, plastic, metal, or the like is used as a core material, and is bonded to the upper and lower surfaces of the honeycomb material 7 with an adhesive 9 to a surface material 8 to form a planar diaphragm. With this configuration, a speaker with a flat sound pressure frequency can be obtained.

Problems to be Solved by the Invention However, in the case of the former cone-shaped diaphragm 6, speakers with cone-shaped or other indentations may have a problem in sound pressure frequency characteristics as shown in FIG. The drawback was that peak dips occurred.

Since the latter planar diaphragm has a lower resonance frequency than the cone-shaped diaphragm 6, it drives the intra-nodal portion of the planar diaphragm at the first resonance frequency to increase the piston vibration band. It uses a so-called node drive method. However, the nodal drive method requires a coupling body to transmit the driving force to the internal part of the nodal, which not only has a more complicated structure than the cone-shaped diaphragm 6, but also inevitably increases the weight of the vibration system. However, as shown in Fig. 3b, the efficiency was low and the cost was high.

FIG. 6 shows a cross section of a conventionally used flat speaker. In FIG. 6, the open end of the coupling cone 11 is adhered to the circular nodal circle 1o, and the other end is connected to the magnetic circuit via the voice coil bobbin 12.

A yoke 13 having a center ball, an annular magnet 14 disposed on the yoke 13, and the magnet 1
The upper plate 15 is disposed on the yoke 13 and constitutes a magnetic circuit.
7 are coupled together, and the peripheral portion of the planar diaphragm 1 is supported by the frame 17 by an edge member 18. The planar diaphragm 18 has a connecting cord 711 connected to the circular nodal circle 10.
A voice coil bobbin 12 provided at the other end is supported by a damper 19 so as to make piston movement within the magnetic gap of the magnetic circuit. Incidentally, in the planar diaphragm 18, a sandwich structure having a honeycomb core material is often used. FIG. 5 shows a cross-sectional view of the honeycomb sand inch diaphragm.

A surface material 8 made of a metal foil such as aluminum is adhered to the end face of an aluminum honeycomb material A through an adhesive 9 to form a diaphragm.

As described above, the planar diaphragm has a more complicated structure than a paper cone, which not only increases cost, but also increases the weight of the vibration system and reduces the efficiency of the speaker.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned drawbacks and provides a speaker diaphragm that easily has flat sound pressure frequency characteristics without using a complex planar diaphragm such as a sandwich structure.

Means for Solving the Problems In order to solve this problem, the present invention provides a dome-shaped or cone-shaped diaphragm having a plurality of substantially polygonal pyramids or path length cones connected to the outer periphery of the diaphragm. A recess is provided in the circumferential direction at each vertex of the vibrating member that serves as a rib, and the voice coil bobbin is bonded to the recess. The driving point is set at a position where the strength of the inner and outer ribs is equalized.

Operation With the above configuration, by dividing the vibrating body, assembling them together, and simultaneously driving the vertices of each, that is, the center of strength, the deflection of the sound radiation surface of the diaphragm can be made much smaller than that of a single cone, and it can be flattened. Since it is close to the diaphragm, it is possible to suppress peak dips in sound pressure frequency characteristics due to depressions. Furthermore, by forming the diaphragm into a curved shape in which the inclination angle decreases as it approaches the driving point, peaks due to high trench resonance are suppressed, and a gentler sound pressure frequency characteristic is realized.

As described above, although the diaphragm has a simple configuration, it can obtain characteristics equivalent to those of a conventional planar diaphragm, or better characteristics than a honeycomb planar diaphragm in terms of suppressing resonance peaks. In the present invention, since the driving force is divided into a plurality of vibrating members, split resonance occurs and the piston vibrates to a high frequency. Furthermore, since each vibrating member has a shape close to a cone shape, sufficient characteristics can be obtained even if the vibrating member is made of a lightweight and inexpensive material such as paper or plastics.

In addition, it does not have a complicated structure such as a honeycomb sandwich structure and does not require a skin material, so it is easy to work with.

EXAMPLE A speaker diaphragm according to an example of the present invention will be described below.

FIG. 1 shows a sectional view of a speaker diaphragm and a vibration system according to the present invention, and FIG. 2 is a plan view of FIG. 1 viewed from the arrow.

As for the material and molding method of the diaphragm of the present invention, thermoplastic resin or thermosetting resin is obtained by heating vacuum molding method or hot press molding method.

As shown in FIG. 1, there are a valley line 3, a ridge line 1, and a ridge line 2, and the shaded area is an inclined surface.

The density of the triangular pyramid (rib) that connects the valley line 3 and the ridge lines 1 and 2 is equal on the inside and outside, that is, at about 7 of the diameter of the diaphragm.
The 0% position is the deepest, and a recess 4 is provided at the apex of the continuous triangular pyramid (rib) in this part, and in the recess 4 in advance,
Apply adhesive and join the voice coil bobbin 5. As a result, the nodal circle where the primary resonance of the disk appears is fixed by the voice coil bobbin 6, thereby suppressing split resonance.

This voice coil bobbin 6 is incorporated into a magnetic circuit similar to that shown in FIG.

The above diaphragm will be compared with a conventional product.

Diameter: φ28 Overall height: 1 Effects of the invention As described above, the present invention provides a rib having a plurality of substantially rectangular conical shapes or a substantially polygonal pyramid shape with open ends connected, and the apex of each rib, that is, the mechanical center. Since a recess is provided at the point and the voice coil bobbin is joined, the entire surface is not coated with adhesive, which reduces weight, and by driving with the voice coil bobbin, the speaker has a flat sound pressure frequency characteristic and high efficiency. be able to. In addition, since the diaphragm has a shape that can be integrally molded, it can be manufactured easily and the cost can be reduced.

Furthermore, by forming the diaphragm with an inclination that decreases as it approaches the driving point of the recess, it is possible to obtain a speaker with a low high-frequency resonance peak, which also has the effect of facilitating system design.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a speaker diaphragm according to an embodiment of the present invention, Fig. 2 is a plan view of Fig. 1 viewed from the arrow, and Fig. 3 is the sound pressure frequency characteristics of the product of the present invention and the conventional product. Comparative views, FIGS. 4 to 6 are cross-sectional views of a conventional speaker diaphragm and a conventional speaker. 1...Ryou line, 2...Ryo line, 3...
... Valley line, 4 ... Concavity, 6 ... Voice coil bobbin. Name of agent: Patent attorney Toshio Nakao and one other person
2--151; 1 Plot 3-Outside 5--Boys] Figure 2 Figure 3 pump (tfx) Figure 4 Figure 5 Figure 6 f' , L! 13

Claims (3)

[Claims] (1) A recess in the circumferential direction at each apex of the vibrating member, in which a plurality of substantially polygonal pyramids or substantially polyconical shapes whose open ends are connected to the outer periphery of a dome-shaped or cone-shaped diaphragm serve as ribs. A diaphragm for a speaker, characterized in that the concave portion is provided with a driving point for joining a voice coil bobbin. (2) The speaker according to claim 1, wherein each of the substantially conical or polygonal pyramidal vibrating members has a curved shape whose inclination angle decreases as it approaches the driving point of the recess. diaphragm. (3) The speaker diaphragm according to claim 1, characterized in that the recesses are provided at positions where the strength is equal to the density of the ribs.