JPH08102993A - Inverted dome speaker - Google Patents

Abstract

PURPOSE: To provide speaker excellent in a high frequency characteristic by adopting a composite material of a microbiological cellulose and a high elasticity fiber for a material of the diaphragm to obtain a high strength and a high internal loss. CONSTITUTION: A microbiological cellulose is disaggregated in water and paper- made to have a prescribed thickness by using a paper making net. In the case of paper-making process, the material is made composite by blending a high elastic fiber such as highly elastic carbon fiber or aramid fiber or a regulator with proper property such as flaky mica to the cellulose to obtain a diaphragm material with a desired characteristic. in the case of assembling, a voice coil bobbin 2a and a damper 2b are formed integrally, the bobbin 2a is provided in a magnetic gap 8 and an outer circumferential part of the damper 2b is adhered to a frame 9. The inverted dome diaphragm 1 made of the microbiological cellulose has a high Young's modulus and an excellent internal loss ca. Thus, the strength and the reliability for a high input signal are improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a loudspeaker, which is a type of audio equipment, and more specifically, the diaphragm has a so-called inverted dome shape, and the diaphragm material is mainly composed of microbial biocellulose. Dome type speaker.

[0002]

2. Description of the Related Art An inverted dome type diaphragm is a diaphragm whose curved surface protrudes downward in a dome shape in a front vertical cross section. It has features.

In the cone type speaker, the sound pressure characteristic can be disturbed due to the effect of the front chamber due to the depression in the front surface of the diaphragm.
Further, since it is difficult to obtain the rigidity of the diaphragm and the high-frequency characteristics do not extend in the flat speaker, there are few cases where it has been successfully commercialized. On the other hand, the inverted dome type has a shallow dome shape, so that an appropriate shape rigidity can be obtained and an ideal performance without the anterior chamber effect can be obtained.

Unlike the cone type speaker, the inverted dome type does not have a cap portion adhered and has an integrated diaphragm, so that there is little variation in high frequency characteristics and stability is achieved. Further, since the shape is spherical and the rigidity is high, the divided vibration frequency becomes high, and the distortion in the middle frequency range can be reduced.

Due to its structure, a normal dome type speaker is generally provided with a tapered short horn on the outer peripheral portion of the diaphragm. In the case of a hard dome, the sound emitted from the diaphragm caused a dip on the sound pressure characteristics in the high frequency range due to the interference between the direct sound and the reflected sound from the short horn. A ring-shaped equalizer is also used as a protector to cancel this dip. In contrast,
In the case of the inverted dome type, the diaphragm is concave and a short horn is not required, so flat characteristics can be obtained, and protectors such as an equalizer and a metal cover can be deleted, so that clear sound quality can be reproduced.

It is generally said that the dome type speaker has good directivity, which is due to the small diameter of the diaphragm. However, it is an inverted dome type and has a diaphragm outer shape of about 0.
By driving the optimum position inside 75 times and controlling the high frequency characteristics, it is possible to further improve the directivity as compared with a dome type speaker having the same diameter.

In the inverted dome type, since the diaphragm can be made shallower than the general cone type, in the multi-way type speaker, there is little difference in the signal arrival time from each speaker unit to the listening position and the cross due to the phase shift. Waveform distortion in the vicinity of over is reduced. In addition, even if the phase difference is completely corrected, the position adjustment between the front and rear of the units is small, so that the structure of the baffle plate can be simplified.

[0008]

As described above, the inverted dome type speaker has excellent characteristics in frequency characteristics and directivity as compared with the cone type speaker and the like. However, the conventional diaphragm material has a low Young's modulus, which lowers the high-frequency limit frequency (fh), and a material such as aluminum having a high Young's modulus has a small internal loss tan δ of 0.002, so fh Since the peak of was sharpened and good sound quality could not be obtained, it was improved by using a damping agent such as a dumping agent or butyl rubber, but the sensitivity decreased because the mass of the vibration system increased. In addition, there is a problem in that the transient characteristic is deteriorated and it cannot be put to practical use.

The present invention has been proposed in view of the above circumstances, and its main object is to use a diaphragm material composed of a composite material of microbial biocellulose and highly elastic fibers having excellent physical properties. An object of the present invention is to provide an inverted dome type speaker that fully utilizes the characteristics of the dome type.

In this case, for other purposes, the reverse dome type is designed to improve the assembling workability, facilitate the bonding work between the diaphragm and the voice coil bobbin, improve the bonding strength, and control the characteristics. To provide a speaker.

[0011]

In order to achieve the above object, the present invention uses a vibrating plate material composed of a composite material of microbial biocellulose and high elasticity fiber. Further, in addition to the high-elasticity fiber, an adjusting material for adjusting physical properties is mixed if necessary.

Further, in order to achieve another object, a damper 2b is provided for the inverted dome type diaphragm 1 made of the above diaphragm material.
A voice coil bobbin type damper 2 in which the voice coil bobbin 2a and the voice coil bobbin 2a are integrated is joined to the back surface of the diaphragm.
Workability is improved.

A plurality of holes h are formed in the roll portion b of the voice coil bobbin type damper 2.

Further, an adhesive surface 2c is attached between the voice coil bobbin 2a and the damper 2b of the voice coil bobbin type damper 2 so as to be adhered to the rear surface of the diaphragm.

Further, a taper portion 2d is formed between the damper 2b and the voice coil bobbin 2a, the joint portion with the inverted dome type diaphragm 1 is changed, the drive position is adjusted, and the control of the characteristics can be adjusted. ing.

Further, an adhesive adapter ring 11 is interposed between the inverted dome type diaphragm 1 and the cylindrical voice coil bobbin 2A to improve the adhesiveness between them.

Further, a taper portion 11d is formed on the adhesive adapter ring 11 to adjust the driving position.

[0018]

[Function] The microbial biocellulose can be produced as a gel-like substance by culturing a microorganism such as acetic acid bacterium. The microbial biocellulose is disintegrated in water and, as is well known, a predetermined amount is obtained using a paper making net. A diaphragm material can be obtained by making the paper into a thickness. The inverted dome type diaphragm 1 made of this microbial biocellulose has a high Young's modulus and an excellent internal loss of tan δ 0.03.

This microbial biocellulose has the property of wrapping other materials. Therefore, at the time of papermaking, high elasticity fiber such as high elasticity carbon fiber or aramid fiber, or in addition to this, if necessary, other adjusting agents for adjusting appropriate physical properties such as scale-like mica are mixed. The composite material is formed into a composite material so that desired characteristics can be obtained.

By adjusting the types and amounts of these, it is possible to obtain desired physical properties suitable for the application, such as high-pitched sound, middle-pitched sound, low-pitched sound, and full range.

When assembling, the voice coil bobbin 2a and the damper 2b are integrally formed by using the voice coil bobbin type damper 2 to form the damper 2b.
The strength of the boundary between the voice coil bobbin 2a and the voice coil bobbin 2a is remarkably improved, and the reliability of the speaker at high input is improved.

Further, since the voice coil bobbin 2a and the damper 2b are integrated, the step of bonding the damper part is not required, so that the productivity is improved.

Further, by providing the adhesive surface 2c at the boundary between the voice coil bobbin 2a portion and the damper 2b portion, the adhesive strength is improved and the reliability due to high input is improved. Furthermore, since the adhesive force is stable, the sound pressure characteristics are stable and variations can be reduced.

Further, since the voice coil bobbin 2a has an integrated damper 2b, the voice coil bobbin 2 is
Since lateral vibration (rolling) of a can be prevented, stable vibration performance can be obtained and high input can be achieved.

Further, by providing a large number of holes h in the roll portion b of the damper 2b, the stiffness can be controlled and the sound pressure radiation due to the vibration of the damper surface can be reduced, so that the sound quality is not affected.

It is also possible to select the characteristic by adjusting the driving position of the inverted dome type diaphragm 1 by increasing the diameter of the upper portion of the voice coil bobbin 2a in a tapered shape with respect to the diameter of the voice coil bobbin 2a.

Conventionally, it has been extremely difficult to stably apply the adhesive on the circumference of the upper end portion of the voice coil bobbin 2a. However, in the case of a speaker having a relatively large voice coil bobbin diameter, a vibration plate is provided above the voice coil bobbin. Adhesive strength, adhesive workability, etc. are improved by using the adhering adapter ring 11 conforming to the shape, and the voice coil bobbin 2
It is possible to reinforce the deformation strength of a.

A taper portion 11d is formed on the adhesive adapter ring 11 to change the driving point so that desired characteristics can be obtained.

[0029]

First Embodiment FIG. 1 is a half sectional view of an inverted dome type speaker according to the first embodiment of the present invention. In the figure, reference numeral 1 denotes an inverted dome diaphragm, and as the diaphragm material, a composite material of microbial biocellulose and a reinforcing material such as a highly elastic fiber is used.

Carbon fiber, aramid fiber or the like is preferably adopted as the reinforcing material for the high elastic fiber. Further, as the adjusting material for adjusting the physical properties, any of scale-like mica and wood pulp, non-wood pulp,
Alternatively, a combination is selected. The blending ratio of them is determined according to the application.

Reference numeral 2 is a voice coil bobbin type damper in which a cylindrical voice coil bobbin 2a and a damper 2b are integrated. This structure has the advantage that the strength of the boundary between the damper 2b and the voice coil bobbin 2a is significantly improved and the reliability at the time of high input is increased. A taper-shaped adhesive surface 2c for adhering to the inverted dome type diaphragm 1 is formed at the boundary portion, that is, the upper portion of the voice coil bobbin 2a, which improves reliability at high input and adhesive strength. Has been planned. 3 is an adhesive. As a molding material for this member, it is preferable to use a thermosetting, highly heat-resistant, high bending strength film material such as PPTA or polyimide.

Reference numeral 4 is a magnetic circuit. This magnetic circuit 4
A yoke 5 having an inverted T-shaped cross section, a ring-shaped magnet 6 provided on a flange portion of the yoke 5, and a ring-shaped plate 7 provided on the magnet 6 are provided. A magnetic gap 8 is formed between the inner peripheral surface and the outer peripheral surface above the center pole 5a of the yoke 5.

A voice coil bobbin 2a having a voice coil is provided in the magnetic gap 8.
The outer peripheral portion of the damper 2b is adhered to the frame 9 provided on the plate 7. That is, frame 9
Has a first step 9a at the top and a second step 9 at the bottom.
b, the inverted dome type diaphragm 1 is coupled to the first step portion 9a via the gasket 10. Further, the outer peripheral portion of the damper 2b is coupled to the second step portion 9b.

An example of assembling this speaker is as follows. The voice coil bobbin 2a, the diaphragm 1 and the frame 9 are bonded in advance using a jig to form an assembly. The outer peripheral portion of the plate 7 or a dowel (not shown) is guided, and the above assembly is loaded and assembled (screwed or bonded). The plate 7 and the frame 9 are preliminarily guided to have a dimensional accuracy and structure such that the voice coil becomes the center of the magnetic circuit 4. Another assembly method is as follows. The frame 9 is bonded or insert-molded to the magnetic circuit 4. The bobbin 2a is adhered using a voice coil center gauge. Take the center gauge and bond the diaphragm 1.

FIG. 2 is a vertical sectional view of the voice coil bobbin type damper 2. If a large number of holes h are formed in the damper roll part b of the damper 2b along the circumferential direction at appropriate intervals, the stiffness can be controlled accordingly and the sound pressure radiation due to the vibration of the damper surface can be reduced. Good sound quality can be obtained. The hole h does not necessarily have to be formed.

FIG. 3 shows a comparison of the sound pressure-frequency characteristics between the present invention and a conventional tweeter speaker whose diaphragm is made of duralumin. The solid line A is the one of the present invention, which has a voice coil diameter of 25 mm, a diaphragm outer diameter of 35 mm, and is mixed with microbial biocellulose and 60% of carbon fiber. The broken line B represents the conventional example, and a remarkable improvement was seen in the flattening of the dip in the high range and the reproducing characteristic in the high range.

[0037]

Second Embodiment FIG. 4 shows a second embodiment of the present invention. In this embodiment, a taper portion 2d rising obliquely upward is formed between the upper end of the voice coil bobbin 2a and the adhesive surface 2c, and the adhesive portion with the inverted dome type diaphragm 1 is slid upward. .

That is, when the diameter of the inverted dome type diaphragm 1 becomes large, it is necessary to set its driving point to an appropriate position.
In this case, by adjusting the length of the taper portion 2d, it is possible to easily deal with a speaker for medium sound and a bass sound. It should be noted that the characteristics can be adjusted by changing the driving position for the same diameter.

The other structure is the same as that of the above-mentioned embodiment, and therefore the detailed description will be omitted.

[0040]

Third Embodiment FIG. 5 shows a third embodiment of the present invention. This example is characterized mainly in that the adhesive dome ring 11 is used and the inverted dome type diaphragm 1 and the cylindrical voice coil bobbin 2A are integrated. It should be noted that the voice coil bobbin 2A and the damper 2B are separate members and are joined by an adhesive.

The other construction is almost the same as that of the above-mentioned first and second embodiments, except that the through hole 5b for venting air is formed in the central portion of the yoke 5 and the back pressure when the inverted dome type diaphragm 1 is driven. To escape to the outside.

FIG. 6 is an enlarged view of the adhesive adapter ring 11. The adhering adapter ring 11 has a cylindrical voice coil bobbin adhering portion 11b, a taper adhering surface 11a at the upper end thereof, and a bent portion 11c at an upper end thereof, which is inclined downward. Is firmly bonded to the back surface of the inverted dome type diaphragm 1 using an adhesive. As a result, damage at the time of high input can be prevented and reliability can be improved.

[0043]

Fourth Embodiment FIG. 7 shows a fourth embodiment of the present invention. In this example, a taper portion 11d extending obliquely upward is formed between the voice coil bobbin adhering portion 11b and the adhering surface 11a of the adhering adapter ring 11, so that the driving position can be set even for the inverted dome type diaphragm 1 having a large diameter. The feature is that it can be adapted by changing.

The other structure is similar to that of the third embodiment.

[0045]

As described above, according to the present invention as set forth in claim 1, in the speaker provided with the inverted dome type diaphragm 1, since high strength and high internal loss are obtained, the high frequency characteristic is improved. can do.

According to the second aspect of the present invention, more desirable characteristics can be obtained by mixing an adjusting material for adjusting the physical properties in addition to the high elastic fiber.

According to the present invention of claim 3, in addition to the above effects, the voice coil bobbin 2a and the damper 2b are provided.
Since they are integrated, the assemblability is good, and the strength of the boundary between the voice coil bobbin 2a and the damper 2b is significantly improved, so that the reliability at the time of high input is improved.

According to the fourth aspect of the present invention, the stiffness can be controlled, and the sound pressure radiation due to the vibration of the damper surface can be reduced by the presence of the hole h, so that good sound quality can be obtained.

According to the fifth aspect of the present invention, since the adhesive strength is improved, the reliability due to high input is improved, and the adhesive force is stable, so that the high frequency characteristics are stable and the variations can be reduced.

According to the sixth aspect of the present invention, the taper portion 2 is provided between the upper end of the voice coil bobbin 2a and the bonding surface 2c.
Since d is formed and the bonding position with the inverted dome type diaphragm 1 can be adjusted, the drive position can be adjusted, different high frequency characteristics can be obtained from the same diaphragm, and a diaphragm having a large aperture can be used.

According to the present invention as set forth in claim 7, since the adhesive adapter ring 11 is provided, the adhesive can be applied stably, and the workability and strength of the adhesion are improved. The property is also improved.

According to the eighth aspect of the present invention, in the case where the adhesive adapter ring 11 is used, the driving position can be adjusted, so that different characteristics can be obtained even with the same diaphragm, and vibration can be obtained. It can be used even if the plate diameter is large.

[Brief description of drawings]

FIG. 1 is a half sectional view of an inverted dome type speaker according to a first embodiment of the present invention.

FIG. 2 is a vertical sectional view of an example of a voice coil bobbin type damper used in the first embodiment of the present invention.

FIG. 3 shows frequency characteristics of the present invention and a conventional example with respect to sound pressure.

FIG. 4 is a half sectional view of a second embodiment of the present invention.

FIG. 5 is a half sectional view of a third embodiment of the present invention.

FIG. 6 is an enlarged explanatory view of a main part of the third embodiment of the present invention.

FIG. 7 is a half sectional view of a fourth embodiment of the present invention.

[Explanation of symbols]

 1 Inverse dome type diaphragm 2 Voice coil bobbin type damper 2a, 2A Voice coil bobbin 2b, 2B Damper 2c Adhesive surface 2d Tapered part 3 Adhesive 4 Magnetic circuit 5 Yoke 5a Center pole 5b Through hole 6 Magnet 7 Plate 8 Magnetic gap 9 Frame 9a First step 9b Second step 10 Gasket 11 Adhesive adapter ring 11a Adhesive surface 11b Voice coil bobbin adhesive section 11c Bent section 11d Tapered section h Hole

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H04R 9/04 105 A B

Claims (8)

[Claims] 1. An inverted dome type loudspeaker in which the diaphragm shape is a front vertical section, and the curved surface projects downward in a dome shape,
The inverted dome type diaphragm (1) is composed of a composite material of microbial biocellulose and high elasticity fiber, which is an inverted dome type speaker. 2. The inverted dome type speaker according to claim 1, wherein an adjusting material for adjusting physical properties is mixed in addition to the high elastic fiber. 3. A voice coil bobbin type damper (2), wherein a damper (2b) connected to the back surface of the inverted dome type diaphragm (1) is formed integrally with the voice coil bobbin (2a).
The inverted dome type speaker according to claim 1 or 2. 4. A plurality of holes (h) are formed in a roll portion (b) of a voice coil bobbin type damper (2).
The inverted dome type speaker described. 5. The voice coil bobbin type damper (2) according to claim 3, wherein an adhesive surface (2c) is formed between the voice coil bobbin (2a) and the damper (2b) so as to be adhered to the back surface of the diaphragm. Reverse dome type speaker. 6. A taper part (2d) for adjusting a driving point of the inverted dome type diaphragm (1) is provided between an upper end of the voice coil bobbin (2a) of the voice coil bobbin type damper (2) and the bonding surface (2c). The inverted dome type speaker according to claim 5, which is formed. 7. A cylindrical voice coil bobbin (2A) bonded to the back surface of an inverted dome type diaphragm (1) made of microbial biocellulose and high elasticity fiber, or mixed with an adjusting material. An inverted dome type speaker characterized by being joined using an adapter ring (11) for use. 8. A taper portion (11) for adjusting the driving position of the diaphragm between the adhesive surface (11a) of the adhesive adapter ring (11) and the adhesive portion of the voice coil bobbin (2A).
The inverted dome type speaker according to claim 7, wherein a) is formed.