JPS6232798A - Diaphragm for speaker - Google Patents

Abstract

PURPOSE:To manufacture a diaphragm of less deterioration with time by sticking and drying dumping agent solution in which plasticizer and polymer chloride are mixed on a diaphragm substrate for a speaker manufactured in a prescribed shape with fiber material as main material. CONSTITUTION:Beaten raw pulp is manufactured in a sheet shape and after drying, it is pressed and molded in a prescribed diaphragm shape. At the next, BPBG of 10wt% as the plasticizer and polyvinyl chloride of 40wt% as polymer chloride are dissolved in solvent in which toluene and ethyl acetate of 25wt% each are mixed, preparing the dumping agent. The dumping agent is spray- coated evenly on the diaphragm substrate, impregnating it through the substrate. Following that, the substrate after impregnation is dried with a temperature of 100 deg.C for 15min, volatilizing the solvent and fixing evenly the mixture of the BPBG and the polyvinyl chloride on the fiber of the substrate. Thereby, the diaphragm of less deterioration with time can be manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a diaphragm mainly made of pulp fiber material used in electrodynamic speakers.

The position of the speaker diaphragm is shown in the partial cross-sectional view of the conventional electrodynamic speaker shown in FIG. Magnet 1 is on top plate 2
and the lower plate 3, and the center bolt 4 is placed on the lower plate 3, thereby forming a magnetic circuit.

A voice coil bobbin 11 having a voice coil 6 wound thereon is coupled to the cone-shaped diaphragm 5 at the open end of the concave portion, and a center cap 15 is placed thereon. The opening edge of the diaphragm 5 is supported via an edge 9 on the inner periphery of the opening of a frame 8 fixed to the upper plate 2, and a gasket 10 fixes the periphery of the edge 9. Further, the opening end of the concave portion of the diaphragm 5 is supported by a damper 7 fixed to the frame 8 together with the voice coil bobbin 11.

The diaphragm 5 has its outer peripheral edge and inner peripheral edge supported by the edge 9 and the damper 7, moves linearly in the direction of the screw 1 movement together with the voice coil bobbin 11, and makes a certain amount of divided vibration to generate its name. ing.

The conditions required for such a speaker diaphragm are that the density is small.
It has a large Young's modulus, and a moderately large internal loss. Material that satisfies these conditions 1
Conventionally, diaphragms based on paper valves have been widely used.

However, even with paper pulp, peak dips occur in the sound pressure frequency characteristics of the speaker.

Therefore, attempts are being made to increase the internal loss in order to reduce these peak dips and flatten the sound pressure frequency characteristics. Internal losses are generally expressed as tan δ, where tan δ is the energy dissipated per cycle and 1
It is thought to be proportional to the maximum potential energy accumulated per cycle, and is a physical property value related to flattening the sound pressure frequency characteristics of the diaphragm, improving transient characteristics (especially rise characteristics), and reducing distortion. be.

Conventionally, there are methods to improve the internal loss of diaphragms formed by papermaking using wood valves as the main raw material. Methods include adding a filler to form paper, and applying a damping agent to the formed diaphragm afterwards.

However, the method of selecting the wood valve material itself is limited to a few types of wood valves with diaphragms having an internal loss of tan δ = 0.1 or more, for example, and the sound quality is limited to a certain level. J. When adding fillers during paper making, compatibility with the binder becomes a problem, and depending on the filler, only about 20% of the amount added may be produced in the diaphragm, making it uneconomical. Furthermore, apply a damping agent or 1. Conventionally, rubber-based resins and acrylic resins have been used to adhere to the diaphragm using L-immersion, etc., but these resins require a large amount of adhesion to maintain sufficient internal loss. , resulting in an increase in the density Tσ of the diaphragm.

SUMMARY OF THE INVENTION An object of the present invention is to provide a speaker diaphragm that exhibits little change over time over a long period of time.

The speaker diaphragm of the present invention is a speaker diaphragm made of a substrate made of fiber as a main material into a predetermined shape. It is characterized in that it is formed by adhering to at least a portion of the main surface of the substrate and drying it.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

First, a raw material valve of beaten NBKP 20''SR is made into paper, and after drying, it is press-molded into a predetermined diaphragm shape.In this example, a diaphragm base for a woofer with a diameter of 30 cm is prepared.

Next, a solution consisting of a plasticizer and a chlorinated polymer in the proportions shown in Table 1, that is, a damping agent, is prepared.

Table 1 Next, the prepared solution of the damping agent is uniformly sprayed onto the main surface of the prepared diaphragm-shaped substrate to impregnate the damping agent into the substrate. Then, the substrate after impregnation was heated to 100°C.
Dry at a temperature of 15 minutes to volatilize the solvent components! A mixture of BPBG and polyvinyl chloride is uniformly adhered to the m-fibers of the base to obtain the diaphragm of this example.

The physical property values of the speaker diaphragm of this example thus obtained are as shown in Table 2. For comparison, Table 2 also lists the physical property values of an untreated diaphragm substrate that was not impregnated with the novel damping agent of this example.

Table 2 From Table 2, it can be seen that the diaphragm treated with the damping agent according to the example of Kinomi fAi increases internal loss while suppressing an excessive increase in density, which is unprecedented.

Figure 2 shows an electrodynamic speaker using the photographic plate of this example obtained in this manner and an electrodynamic speaker manufactured using an untreated diaphragm substrate that is not treated with damping agent ζ cloth. It is a graph which shows each sound pressure output frequency characteristic. In the graph, curve A represents the vibration plate of this example, and curve B represents the vibration plate of this example.
indicates the result from an unprocessed imaging plate. As can be seen from FIG. 3, in the electrodynamic speaker using the diaphragm of this example, the dip around 550 Hz in the mid-to-high range is flattened and improved.

In this example, the damping agent is applied to the entire surface of the diaphragm-like substrate by coating! However, if a part of the diaphragm is attached, for example, near the inner circumference or the outer circumference (= near J, etc.)
It's okay to stop. In addition, in the eleventh attachment method, the diaphragm substrate can be immersed to impregnate and adhere the damping agent.

In addition, the components of the dumping agent in this example were chlorinated polymer, the plasticizer and solvent were polyvinyl chloride, B P
8 G (butyl-phthalyl-buty
l glyc.

However, as the chlorinated polymer, for example, chlorinated polypropylene may be used, and as the plasticizer, for example, DOP (diocty
l phthalate), DBP (dibu
tyl phthalate), B L P (b
utyl-1auryl phthalatc), 7
CP (tricresyl phoshatc),
DOA (dioctyI adipate), Q
O8 (dioctyl 5ebacate) etc. may be appropriately mixed and used, and aromatic organic solvents such as xylene, methanol, isopropanol, alcoholic solvents, and ester organic solvents and ketones may be used as solvents. Organic solvents may also be used.

Polymers, ie, conjugates, generally become more difficult to dissolve in organic solvents as they become more polymeric; however, by chlorinating them, the low polymer molecules are polarized, making them easier to dissolve in solvents. Also, if plasticizer is added in large quantities, a migration phenomenon will occur,
Adhesive effectiveness may be reduced. In the present invention, the plasticizer is used in the weight ratio of the plasticizer to the chlorinated polymer:
Good adhesion results are obtained when the ratio of chlorinated polymer is in an amount in the range of 5 to 60:100, preferably 15 to 25:100.

Further, although a diaphragm is shown in this embodiment, the present invention can also be applied to an edge or damper that supports a diaphragm using a predetermined base.

11 Hemoplast 1 According to the present invention, the dry and hardened novel damping agent itself has appropriate flexibility and heat resistance up to about 100°C,
And because it has the property of not attacking fiber materials,
By attaching the damping agent containing a plasticizer and a chlorinated polymer to the base of a diaphragm made of fiber material as a main raw material, a diaphragm for a speaker with little change over time can be obtained.

[Brief explanation of drawings]

Figure 1 is a partial sectional view of an electrodynamic speaker, and Figure 2 is a dynamic N-type speaker using the imaging plate of this example and an untreated diaphragm substrate that is not coated with a damping agent. It is a graph showing each A voltage output frequency characteristic of manufactured A type speakers. Explanation of symbols of main parts 1... Magnet 2... F section plate 3... Lower plate 4... Center ball 5... Cone-shaped imaging plate 6... Voice coil 7... Damper 8... Frame 9... Edge 10... Gasket

Claims (2)

[Claims] (1) A speaker diaphragm consisting of a base made of fiber material as a main material into a predetermined shape, in which a solution of a damping agent made of a mixture of a plasticizer and a chlorinated polymer is applied to the base and dried. A speaker diaphragm characterized by: (2) The speaker diaphragm according to claim 1, wherein the solution of the damping agent is impregnated and adhered to the main surface of the substrate by dipping or coating.