JP2000152375A - Speaker diaphragm. its manufacturing apparatus and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a speaker diaphragm made of magnesium. SOLUTION: After an upper die 21 is made to be in contact with a lower die 23 with a magnesium plate 28 inbetween, the upper die 21 and the lower die 23 both descend and reach a fixed stand 22. While the upper die 21 and the lower die 23 descend, they receive an upward buffer force. Thus, when the upper die 21 made contact with the lower die 23, the magnesium plate 28 does not receive a maximum pressure from the upper die 21 and the magnesium plate 28 receives the maximum pressure of the upper die 21, when the upper die 21 and the lower die 23 reach the fixed stand 22. Thus, the magnesium plate 28 receives drawing process into the speaker diaphragm without causing hardening.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diaphragm for a speaker, an apparatus for manufacturing the same, and a method for manufacturing the same.

[0002]

2. Description of the Related Art In general, there are four physical properties required for a material of a speaker diaphragm. (1) High Young's modulus (2) Low density (3) High sound velocity (4) High internal loss Currently, aluminum or titanium is frequently used as a metal material satisfying such physical properties. I have.

[0003]

However, with the recent improvement in performance of acoustic devices, it has been demanded that speaker diaphragms further improve the above-mentioned physical properties.

The inventor of the present invention has conducted various experiments, and has found that magnesium is superior to aluminum and titanium in acoustic properties as a material for a speaker diaphragm. The acoustic characteristics of speaker diaphragms made of aluminum, titanium, and magnesium are described below.

Young's modulus (GPa) Density (kg / m ³ ) Aluminum 71 2700 Titanium 110 4500 Magnesium 115 1740 Sound velocity (m / sec) Internal loss Aluminum 5130 0.002 Titanium 4950 0.002 Magnesium 8120 0.003 The speaker diaphragm made of magnesium has a higher Young's modulus, a smaller density, a higher sound velocity, and a larger internal loss than a speaker diaphragm made of aluminum or titanium. That is, it has been proved that magnesium is much superior to aluminum or titanium as a material of the speaker diaphragm.

As described above, magnesium has been found to be excellent as a material for a speaker diaphragm. However, manufacturing a speaker diaphragm made of magnesium has the following problems. FIG. 2 is a schematic diagram of a conventional drawing press apparatus for manufacturing a speaker diaphragm using aluminum or titanium as a material.

A conventional drawing press apparatus 10 shown in FIG.
Comprises a movable upper mold 11 formed so as to be capable of linear movement in the vertical direction A, and a fixed lower mold 12 fixed in the linear movement direction of the movable upper mold 11. The movable upper die 11 is moved vertically downward toward the fixed lower die 12, and the aluminum plate or titanium plate 13 is pressed between the movable upper die 11 and the fixed lower die 12, thereby forming the aluminum plate or titanium plate 13. Can be formed in a cone shape as a speaker diaphragm.

However, when the drawing press of the magnesium plate is performed by using the conventional drawing press apparatus 10 shown in FIG. 2, the tip of the cone (at the bottom 14 of the fixed lower die 12 shown in FIG. 2). Cracks or cracks occur in the formed part).

This is because magnesium has higher hardness and lower elongation than aluminum and titanium, and also causes work hardening of the material. For this reason, when deep drawing of magnesium is performed, a crack or a crack occurs at the tip of the drawn product.

[0010] Therefore, unless magnesium and aluminum having low hardness and high elongation can be drawn and pressed as compared with aluminum or titanium, it is difficult to produce a magnesium speaker diaphragm having good acoustic characteristics. Impossible.

The present invention has been made in view of the above problems, and a drawing press device and a drawing device capable of deep drawing a magnesium plate and, consequently, manufacturing a diaphragm for a speaker made of magnesium. The aim is to provide a method.

[0012]

In order to achieve this object, a second aspect of the present invention is directed to an upper die formed so as to be capable of linear movement in one direction, and a fixed base fixed on the one hand. A lower mold that is arranged between the upper mold and the fixed base and is formed to be capable of linearly moving in one direction with respect to the fixed base, and a cushioning member that is arranged between the fixed base and the lower mold. To provide a drawing press apparatus.

In the conventional drawing press device, the movable upper die 11 is fitted into the fixed lower die 12 in a very short time. The maximum pressure acts on the metal material 13, which causes work hardening.

According to the drawing press apparatus of the present invention,
The upper die moves toward the lower die, contacts the lower die, and then moves together toward the fixed base. During this time, the upper die and the lower die receive a buffering force from a buffer member disposed between the fixed base and the lower die. Therefore, when the upper die contacts the lower die, the material sandwiched between the upper die and the lower die does not receive the maximum pressure from the upper die.

The lower mold reaches the fixed base while the upper mold and the lower mold are in contact with each other. At this point, the material sandwiched between the upper mold and the lower mold receives its maximum pressure from the upper mold.

As described above, in the drawing press apparatus according to the present invention, the material to be drawn is sandwiched between the upper die and the lower die until the maximum pressure is received from the upper die. A considerable amount of time has passed. Therefore, unlike the conventional drawing press, the maximum pressure of the upper die does not act on the material in a very short time, and after the upper die and the lower die contact,
Since the pressure of the upper mold gradually acts on the material until the lower mold abuts on the fixed base, it is possible to prevent the work hardening from occurring in the material.

[0017] As described in claim 3, it is preferable that the cushioning member can adjust the cushioning force.

By adjusting the cushioning force of the cushioning member, the drawing press can be appropriately performed in accordance with the thickness of the material and the shape of the cone.

[0019] As described in claim 4, the cushioning member causes the lower die to receive about 50% to about 90% of the maximum pressure of the upper die when the upper die is fitted with the lower die. Preferably, it is

By adjusting the cushioning force of the cushioning member so as to realize such a state, the drawing press allows
For example, a speaker diaphragm having a desired shape can be formed.

According to the experimental results of the inventor, in particular, when the upper die is fitted with the lower die, the lower die has about 80% of the maximum pressure of the upper die.
Most preferably.

As described in claim 5, it is preferable that the cushioning member is such that the lower die receives the maximum pressure of the upper die when the lower die contacts the fixed base.

In this manner, after the upper mold and the lower mold come into contact with each other, the pressure of the upper mold gradually acts on the material until the lower mold contacts the fixed base. Work hardening can be prevented.

As the cushioning member, for example, a spring can be used.

[0025] As described in claim 7, a recess is formed in the fixing base, and a receiving base whose height can be freely adjusted is provided on the bottom surface of the recess. It may be arranged between the receiving table and the fixed table.

With such a configuration, the free length of the spring can be freely adjusted, and the cushioning force of the spring can be freely adjusted.

Also, as described in claim 8,
It is also possible to use a damper as a buffer member.

As described above, according to the drawing press apparatus according to claims 2 to 8, deep drawing can be performed without causing work hardening of the material. Therefore, as described in the ninth aspect, it is possible to form a speaker diaphragm made of magnesium by pressing a magnesium metal plate using the present drawing press apparatus.

According to a tenth aspect of the present invention, a material is sandwiched between the upper mold and the lower mold, a pressing force is applied to the upper mold and the lower mold, and the material is sandwiched. At the time when the upper mold comes into contact with the lower mold, the material receives a pressure less than its maximum pressure from the upper mold, and both the upper mold and the lower mold move,
When the upper mold and the lower mold reach a predetermined position, the material receives the maximum pressure from the upper mold.

According to this drawing method, the same effect as the drawing press device according to the second aspect can be obtained.

In the throttling method according to the tenth aspect, as described in the eleventh aspect, the pressure lower than the maximum pressure is preferably about 50% to about 90% of the maximum pressure of the upper die. . In particular, the preferred pressure is about 80% of the maximum pressure of the upper mold.

As the predetermined position in the squeezing method according to the tenth aspect, for example, as described in the twelfth aspect, a fixed base arranged below the lower die can be selected.

According to the thirteenth aspect, this drawing method also enables deep drawing of magnesium without causing work hardening.

[0034]

FIG. 1 is a schematic diagram showing the configuration of a drawing press apparatus according to an embodiment of the present invention.

The drawing press device 20 according to the present embodiment comprises:
A movable upper die 21 formed to be linearly movable in the vertical direction A, a fixed base 22 fixed in the linear movement direction of the movable upper die 21, and disposed between the movable upper die 21 and the fixed base 22. A movable lower mold 23 formed to be linearly movable in the vertical direction A with respect to the fixed base 22, and a spring 24 as a buffer member disposed between the fixed base 22 and the movable lower mold 23. ing.

A concave portion 22a is formed at the center of the fixed base 22, and a plurality of guide posts 25 (only two guide posts 25 are shown in FIG. 1) from the upper surface 22b of the side wall around the concave portion 22a. ) Is extended.

The movable lower die 23 has a through hole 26 having an inside diameter into which the guide post 25 can be fitted, at a position corresponding to the guide post 25. By fitting the guide post 25 of the fixed base 22 into the through hole 26 of the movable lower die 23, the movable lower die 23 can make a linear motion in the vertical direction A with respect to the fixed base 22. .

A receiving stand 27 is attached to the bottom surface of the concave portion 22a formed in the fixing stand 22. Cradle 27
Has a screw portion 27a extending downward, and the screw portion 27a is provided in a screw hole 22 provided in the center of the concave portion 22a.
c. By rotating the screw portion 27a, the height of the receiving stand 27 with respect to the bottom surface of the concave portion 22a can be freely adjusted. The length of the screw portion 27a is determined so that the receiving table 27 is not located above the upper surface 22b of the side wall of the fixing table.

The spring 24 as a buffer member is disposed between the receiving table 27 and the bottom surface of the movable lower die 23. By changing the height of the pedestal 27, the free length of the spring 24 can be changed, and the urging force of the spring 24 can be changed.

The drawing press apparatus according to the present embodiment having the above-described configuration operates as follows. In the following description, it is assumed that the magnesium plate 28 is drawn into a speaker diaphragm shape using the present drawing press device.

First, the movable upper mold 21 is moved downward to the movable lower mold 23.
, And comes into contact with the magnesium plate 28. The movable upper die 21 continues to descend, and the magnesium plate 28 is sandwiched between the movable upper die 21 and the movable lower die 23.

The movable upper mold 21 that has come into contact with the movable lower mold 23 with the magnesium plate 28 interposed therebetween continues to descend toward the fixed table 22 together with the movable lower mold 23. During the lowering, the movable upper mold 21 and the movable lower mold 23 receive an upward buffering force from the spring 24 as a buffering member. Therefore, when the movable upper mold 21 contacts the movable lower mold 23, the magnesium plate 28 sandwiched between the movable upper mold 21 and the movable lower mold 23 receives the maximum pressure from the movable upper mold 21. Never.

In the present embodiment, the cushioning force of the spring 24 is set such that the magnesium plate 28 is moved upward while the movable upper die 21 and the lower movable die 23 are lowered toward the fixed base 22 in the fitted state. It is adjusted to receive about 80% of the maximum pressure of the mold 21.

Thereafter, the movable lower mold 23 and the movable lower mold 23 are kept in contact with each other, and the movable lower mold 23 is
On the upper surface 22b of the side wall of. At this point,
The magnesium plate 28 sandwiched between the movable upper mold 21 and the movable lower mold 23 receives the maximum pressure from the movable upper mold 21.

As described above, according to the drawing press apparatus 20 according to the present embodiment, the magnesium plate 2 to be drawn is
A certain period of time elapses between the time when the movable mold 8 is sandwiched between the movable upper mold 21 and the movable lower mold 23 and the time when the maximum pressure is received from the movable upper mold 21. Therefore, unlike the conventional drawing press apparatus 10 shown in FIG. 2, the maximum pressure of the upper mold 11 does not act on the metal material 13 in a short time.
After the movable upper mold 21 contacts the movable lower mold 23, the movable lower mold 2
The movable upper die 2 gradually moves until the base 3 contacts the fixed base 22.
A pressure of 1 acts on the magnesium plate 28. As a result, work hardening of the magnesium plate 28 can be prevented, and the magnesium plate 28 can be formed as a speaker diaphragm.

In the above-described embodiment, the spring 24 is used as the cushioning member. However, any member having a buffering action can be used as the cushioning member. For example, a damper may be used instead of the spring 24. It is preferable that the damper can also adjust the buffering force.

[0047]

According to the first aspect of the present invention, there is provided a speaker diaphragm made of magnesium which has better acoustic characteristics than aluminum and titanium.

According to the drawing press apparatus according to the second to ninth aspects, it is possible to manufacture a magnesium speaker diaphragm which cannot be manufactured by the conventional drawing press apparatus.

Similarly, the diaphragm method according to the tenth to thirteenth aspects can produce a magnesium speaker diaphragm which cannot be produced by the conventional diaphragm method.

[Brief description of the drawings]

FIG. 1 is a schematic side view of a drawing press device according to an embodiment of the present invention.

FIG. 2 is a schematic side view of a conventional drawing press device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Conventional draw press apparatus 11 Movable upper mold 12 Fixed lower mold 13 Aluminum plate or titanium plate 14 Bottom part of fixed lower mold 20 Draw press apparatus 21 according to one embodiment of the present invention 21 Movable upper mold 22 Fixed base 23 Movable lower mold 24 Spring 25 Guide post 26 Through hole 27 Cradle 27a Screw part 28 Magnesium plate

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Koichi Minami F term (reference) 5D016 AA09 EC25 HA07 JA17 in 43 Kanda Konya-cho, Chiyoda-ku, Tokyo

Claims (13)

[Claims] 1. A speaker diaphragm made of magnesium. 2. An upper mold formed so as to be capable of linear movement in one direction, a fixed base fixed in the one-sided improvement, and disposed between the upper mold and the fixed base, with respect to the fixed base. A lower die formed so as to be capable of linear movement in the one direction, and a buffer member disposed between the fixed base and the lower die. 3. The drawing press apparatus according to claim 2, wherein said buffer member is capable of adjusting its buffering force. 4. The cushioning member according to claim 1, wherein when the upper mold is fitted with the lower mold, the lower mold has a maximum pressure of about 50% of a maximum pressure of the upper mold.
4. A drawing press according to claim 2 or 3 wherein said drawing press receives between about 90% and about 90%. 5. The cushioning member according to claim 2, wherein the lower die receives a maximum pressure of the upper die when the lower die contacts the fixed base. 5. The drawing press device according to any one of 4. 6. The drawing press device according to claim 2, wherein the buffer member is made of a spring. 7. A recess is formed in the fixing base,
A receiving table whose height can be freely adjusted is provided on the bottom surface of the concave portion, and the spring is disposed between the receiving table and the fixed table. The drawing press device according to claim 6. 8. The drawing press apparatus according to claim 2, wherein the buffer member is a damper. 9. The drawing press apparatus according to claim 2, wherein a magnesium metal plate is pressed to form a speaker diaphragm. 10. A material is sandwiched between an upper mold and a lower mold,
In the squeezing method of applying a pressing force to the upper mold and the lower mold and squeezing the material, at the time when the upper mold contacts the lower mold with the material interposed therebetween, the material is removed from the upper mold. Under the pressure below the maximum pressure, the upper mold and the lower mold move together, and when the upper mold and the lower mold reach a predetermined position, the material receives the maximum pressure from the upper mold. An aperture method characterized by the following. 11. The method according to claim 10, wherein the pressure equal to or less than the maximum pressure is about 50% to about 90% of the maximum pressure of the upper die. 12. The drawing method according to claim 11, wherein the predetermined position is a fixed base arranged below the lower die. 13. The drawing method according to claim 10, wherein the material is magnesium.