JPWO2008084796A1 - Electroacoustic transducer - Google Patents

Abstract

No special shape or processing is required as a magnet, it is not necessary to set the magnetization direction finely, and the manufacturing process is extremely simple like a radially magnetized magnet plate, but it is more than a radially magnetized magnet plate. Provided is an electroacoustic transducer capable of efficiently converting electric signals to sound or converting sound to electric signals with a high effective magnetic flux density distribution with respect to a conductor of an acoustic diaphragm with low distortion. In the magnetization direction of each partial area of the magnet plate, in addition to the basic area magnet magnetized so that the component parallel to the vibration surface of the acoustic diaphragm is in the radial direction toward the center of the acoustic diaphragm, the center side of the basic area magnet The central region magnet magnetized so that the component parallel to the central axis of the acoustic diaphragm is in the forward direction of the acoustic diaphragm, or the central axis of the acoustic diaphragm at the outer peripheral side of the basic region magnet At least one of the outer peripheral area magnets magnetized so that the parallel component is in the rear direction of the acoustic diaphragm is provided.

Description

  The present invention relates to an electroacoustic transducer applied to a speaker, a headphone, an earphone or the like that converts an electric signal into sound, or a microphone or a sound wave sensor that converts received sound into an electric signal.

Conventionally, in an electroacoustic transducer called a gummazone type speaker, an acoustic diaphragm on which a planar coil pattern of a conductor corresponding to a voice coil is formed is installed in the middle part of a pair of magnetic field generators, and a drive current is supplied to the conductor. An acoustic diaphragm that has been supplied to vibrate in a direction perpendicular to the plane is used.
The acoustic diaphragm of this Gamson-type speaker has a feature that the entire surface is driven in the same phase and good transient characteristics can be obtained in a wide band because of the structure in which the conductor is disposed almost all over the acoustic diaphragm. is doing.

For example, in (Patent Document 1), NS poles of adjacent strip magnets (or strip regions in a magnet plate) are alternately arranged differently, and the entire magnet plate made up of many strip magnets is formed in a flat plate shape. In addition, an electroacoustic transducer is disclosed in which an acoustic diaphragm in which a conductor is formed so as to face the plane of the magnet plate is disposed so that the direction of the NS pole is perpendicular to the flat plate surface. ing.
In this electroacoustic transducer, since the NS poles are alternately arranged in different directions, there are many portions where the direction of the magnetic field is reversed and portions where the magnetic flux density is low on the acoustic diaphragm. Therefore, the magnetic flux density for driving the acoustic diaphragm in the direction perpendicular to the surface thereof, that is, the magnetic flux in which the direction of the electromagnetic force acting on the conductor of the acoustic diaphragm is the vibration direction (hereinafter referred to as “effective working magnetic flux”). ) Density (hereinafter referred to as “effective magnetic flux density”) also changed greatly. In addition, it is necessary to reverse the winding direction of the conductor in accordance with the direction of the magnetic field to be reversed, or to arrange the conductor in accordance with a region that is partially present and has a high effective action magnetic flux density. For this reason, the entire surface of the diaphragm cannot be a planar coil, and a supporting member such as a synthetic resin sheet that supports the planar coil is indispensable, and sound unique to the supporting member has an adverse effect on sound quality. Furthermore, there is a problem that the driving force of each part of the diaphragm varies greatly, which causes a divided vibration which is a big problem for reproducing high quality sound.

Also, in (Patent Document 2), two magnet plates in which cylindrical and ring magnets are concentrically separated on the center side and the outer peripheral side are opposed to each other, and a conductor is printed in a spiral shape between them. Electroacoustic conversion in which the acoustic diaphragm (planar coil diaphragm) is arranged in parallel with the magnet plate, and the magnetization direction of the magnet is perpendicular to the acoustic diaphragm and the polarity is reversed on the center side and the outer periphery. A vessel is disclosed.
In this electroacoustic transducer, since the conductors are all spirally wound in the same direction, the entire surface of the diaphragm can be a planar coil. Thereby, it becomes possible to generate a driving force on the entire surface of the diaphragm, which is effective for a problem such as (Patent Document 1). However, in the magnet arrangement in which the magnetization direction is only perpendicular to the diaphragm, the area where the magnetic flux density is high becomes very narrow, so the area of the diaphragm cannot be increased. Therefore, it is difficult to adopt as a speaker for a low sound range in which the diameter of the diaphragm is large, and it has been limited to a speaker for a high sound range in order to use it in a state where the use efficiency of magnetic flux is high. In addition, since the change in effective acting magnetic flux density is large at each position of the planar coil, a uniform driving force cannot be obtained on the entire surface of the diaphragm, and the problem of divided vibration cannot be solved.

  As described above, in the conventional magnet plate in which the magnetization direction is only perpendicular to the diaphragm, the region having a high effective magnetic flux density becomes very narrow, and therefore the area of the diaphragm cannot be increased. As a countermeasure, in (Patent Document 2), the area is widened by opening the gap between the magnets on the center side and the outer periphery side, which are two partial areas, but this time the effective working magnetic flux density decreases, Its size was also limited. In the end, it was difficult to adopt as a speaker for a low sound range in which the diameter of the diaphragm becomes large. Further, since the magnetization direction is unidirectional, the adjustment of the distribution of effective working magnetic flux density is mostly due to the change in the interval between the two types of partial regions. In such a limited adjustment, it is difficult to make the distribution of the effective acting magnetic flux density at each position of the acoustic diaphragm uniform, and it is difficult to obtain a uniform driving force on the entire surface of the diaphragm.

In order to solve these conventional problems, the present applicant diligently researched and patented (Patent Document 3), the magnetic plate is divided into many partial areas, and each partial area is used to increase the efficiency of use of the magnet. A magnet plate having a magnetization direction (hereinafter referred to as “magnet plate having an optimum magnetization angle”) is used, and an acoustic vibration plate formed by winding a conductor in a spiral shape is arranged in front of the magnet plate in parallel with the magnet plate. An installed electroacoustic transducer is disclosed. In addition, a component parallel to the vibration surface of the acoustic diaphragm in the magnetization direction of the magnet plate is defined as a radial direction of the magnet plate, and all angles formed with respect to the vibration surface of the acoustic diaphragm are constant (hereinafter referred to as “radius”). An electroacoustic transducer using a similar acoustic diaphragm is also disclosed.
Japanese Examined Patent Publication No. 35-10420 Japanese Utility Model Publication No. 60-93397 Japanese Patent No. 3612319

The new magnet plate employed in the electroacoustic transducer of (Patent Document 3) is capable of uniformly forming a high effective magnetic flux density in one direction over the entire surface of the acoustic diaphragm having a large area. It has characteristics that are not in the list. For this reason, the winding direction of the planar coil of the acoustic diaphragm may be one direction, and the planar coil can be arranged in a very wide range over the entire surface of the acoustic diaphragm.
These features make it possible to design an acoustic diaphragm that can drive the entire vibration surface in the same phase, and to suppress distortion caused by the difference in effective magnetic flux density in the vibration direction of the acoustic diaphragm. It has the excellent effect that it can maintain the sound quality of sound generated in speakers and headphones, etc. and the electrical signal converted from sound in microphones, etc. It was something that could be realized.

(1) However, as a magnet plate having an optimum magnetization angle, for example, the magnet plate is equally divided into seven in the radial direction, and 486 small magnets are concentrically arranged to constitute the whole (see the drawing of Japanese Patent No. 3612319). 4) is used, the magnetic force generated in each small magnet is weak if SR ferrite (strontium ferrite) is used as the magnet material, so PP tape or the like is wound around each row constituting the magnet plate. Each small magnet could be fixed by attaching. However, since the magnetic flux density cannot be increased with SR ferrite, the conversion efficiency to sound energy (hereinafter referred to as “efficiency”) is very low, the Q (sharpness of resonance) becomes too large, and there is a lack of versatility. Had.
(2) Therefore, in order to increase the magnetic flux density, when a high-performance neodymium-iron-boron system (hereinafter referred to as “neodymium”) is adopted as the material of the magnet, the magnetic force acting on each small magnet constituting the magnet plate is 10 It will increase to around double. Therefore, it has been found that due to the strong magnetic force, it is difficult to fix with a PP tape or an adhesive in the production of the magnetic plate. In particular, it is difficult to fix the magnetic component that is parallel to the central axis of the acoustic diaphragm and toward the side where the acoustic diaphragm is installed, and if you try to fix each small magnet with a frame in the direction of the magnetic force, A frame is interposed between the plate and the magnet plate. As a result, the frame could interfere with the longitudinal vibration of the acoustic diaphragm, so that it could not be adopted.
(3) If one more magnet plate is added and installed in front of the acoustic diaphragm and the forces repelling each other are used, the magnetic force can be directed in the opposite direction of the acoustic diaphragm. There is no need to intervene a frame. However, the magnet plate installed in front of the acoustic diaphragm has a great influence on the acoustic characteristics, and it has a problem that it is difficult to use it for hi-fi particularly in the middle range or higher. In addition, since the magnet plates are handled one by one, they are disassembled, so that the design and assembly process is very complicated and lacks mass productivity.
(4) Furthermore, since the direction of the magnetic force acting on each small magnet changes greatly depending on the surrounding magnets, the direction of the magnetic force changes greatly even in the process of assembling the whole, and means for temporarily fixing each assembly process is also required. became. Based on this situation, using a means to securely fix small magnets individually will reduce the area of the magnet part, making the use of magnetic flux very bad and making it difficult to process magnets and frames. The process also increased and became complicated, and had the problem of lacking in productivity.
(5) Compared to the magnet plate with the optimum magnetization angle, the radial magnet plate is a trapezoidal magnet that is a small magnet, with the upper base side being the center side of the magnet plate and the lower base side being the magnet plate. Since it is only necessary to arrange a plurality of pieces in the circumferential direction so as to be on the outer periphery side and sandwich the center side and outer periphery side of the entire magnet plate with a frame, the manufacture of the magnet plate is very simple and excellent in productivity. . However, the magnet plate of radial magnetization has a feature that the use efficiency of the magnetic flux is not good, and the effective working magnetic flux is dispersed in a very wide range and the effective working magnetic flux density is lowered. For this reason, when an acoustic diaphragm is used in a general non-wide area, the utilization efficiency of magnetic flux is further greatly reduced. Especially for loudspeakers that do not have a large diaphragm area, such as those for the mid-range and high-range, it is necessary to concentrate the magnetic flux on the narrow diaphragm area and increase the magnetic flux density, so it cannot be used as it is. There was a problem of lack of versatility and practicality.
In view of the above, there has been a strong demand for the development of an electroacoustic transducer that can improve the utilization efficiency and efficiency of magnetic flux with a simple structure and is excellent in versatility and mass productivity.

  The present invention meets the above-mentioned demands, and does not require a special shape or processing as a magnet, does not require fine setting of the magnetization direction, and the manufacturing process is extremely simple like a radially magnetized magnet plate. Therefore, it is possible to improve the efficiency by significantly increasing the effective magnetic flux density than the radially magnetized magnet plate, and from the electrical signal that sets the distribution of the high effective magnetic flux density for the conductor of the acoustic diaphragm An object of the present invention is to provide an electroacoustic transducer such as a speaker, a headphone, an earphone or the like that can efficiently convert to sound with low distortion, or a microphone or a sound wave sensor that can efficiently convert sound to an electrical signal with low distortion. And

In order to solve the above problems, the electroacoustic transducer of the present invention has the following configuration.
The electroacoustic transducer according to claim 1 is a magnet plate that is formed in a disk shape or a ring shape as a whole, and a planar coil that is formed in parallel with the magnet plate and is formed by winding a conductor in a spiral shape. An electroacoustic transducer having a disk-like or ring-like acoustic diaphragm comprising: a component parallel to a vibration surface of the acoustic diaphragm in the magnetization direction of each partial region of the magnet plate; In addition to the basic region magnet magnetized so as to be in the radial direction toward the center of the diaphragm, a component parallel to the central axis of the acoustic diaphragm is located in front of the acoustic diaphragm at a position on the center side of the basic region magnet. Magnetized so that the component parallel to the central axis of the acoustic diaphragm is in the rear direction of the acoustic diaphragm at a position on the outer peripheral side of the central area magnet or the basic area magnet magnetized so as to be in the direction At least the outer peripheral area magnet Re or has Configurations that includes one.
This configuration has the following effects.
(1) Contribution of the effective magnetic flux to the conductor of the acoustic diaphragm by adjusting the direction of magnetization in each partial region by a magnet plate combining a central region magnet on the center side of the basic region magnet and an outer peripheral region magnet on the outer peripheral side Can be set to increase the minutes. Effectively generate radial magnetic flux along the vibration surface of the acoustic diaphragm by using a magnet plate (hereinafter referred to as “magnet plate with three-direction magnetization”) in which each partial region is set to such an effective magnetization angle. Thus, a region having a high effective magnetic flux density can be secured in a wide range. The effective magnetic flux density is higher than that of the magnetized magnet plate in the radial direction, and the efficiency of the speaker that has been insufficient can be brought to a practical level, and the Q (resonance sharpness) of the speaker for low frequencies that has become too large. The value of can be made practical by lowering the value of.
(2) Compared with a radially magnetized magnet plate, the inner-peripheral region and outer-peripheral region are reduced and narrowed in the region where the effective working magnetic flux density is high, but the effective working magnetic flux density is overall To be high. That is, since the effective working magnetic flux density of the whole can be increased by the amount corresponding to the reduced effective working magnetic flux in the inner peripheral side region and the outer peripheral side region, the effective working magnetic flux can be distributed in a useful region. As described above, the magnet plate of three-direction magnetization increases the effective working magnetic flux density by distributing the effective working magnetic flux in the outer peripheral side region and the inner peripheral side region not used in the acoustic vibrating plate to the useful region used in the acoustic vibrating plate. However, the effective working magnetic flux density can be intensively increased by further narrowing the area to be used.
(3) The direction of magnetization in each partial region is adjusted by a magnetic plate combining a basic region magnet and a central region magnet on its center side, or a magnetic plate combining a basic region magnet and an outer peripheral region magnet on its outer peripheral side. It can be set so that the contribution of the effective magnetic flux to the conductor of the acoustic diaphragm is increased. Effectively generate a radial magnetic flux along the vibration surface of the acoustic diaphragm by using both magnet plates (hereinafter referred to as “bidirectional magnetized magnet plates”) with each partial region having such an effective magnetization angle. Thus, a region having a high effective magnetic flux density can be secured in a wide range.
The magnet plate with two-direction magnetization can narrow the area of the magnet with respect to the region with a higher effective magnetic flux density than the magnet plate with three-direction magnetization. Therefore, when the sound generated from the back side of the acoustic diaphragm is emitted to the back of the electroacoustic transducer, the obstacles due to the magnet are reduced, and the influence on the vibration of the acoustic diaphragm is reduced, thereby preventing the deterioration of the acoustic characteristics.
(4) In a bi-directionally magnetized magnet plate in which a basic area magnet and a central area magnet are combined on the center side, the effective magnetization angle of each partial area is more effective than a radially magnetized magnet plate. In the region where the magnetic flux density is high, the inner peripheral side region is reduced and narrowed, but the effective working magnetic flux density is increased overall. That is, the effective magnetic flux density of the whole can be increased by an amount corresponding to the reduced effective magnetic flux in the inner peripheral side region.
Compared with a magnet plate magnetized in three directions, the effective magnetic flux density is lower overall, but since the outer peripheral area magnet is not adopted, the area with a high effective magnetic flux density is widened to the outer peripheral side, like a speaker for a low sound range. An optimum structure is obtained when the acoustic diaphragm is designed to have a large diameter.
(5) In a bi-directionally magnetized magnet plate in which a basic region magnet and an outer peripheral region magnet are combined on the outer peripheral side, the effective magnetization angle of each partial region is more effective than a radially magnetized magnet plate. In the region where the magnetic flux density is high, the outer peripheral side region decreases and narrows, but the effective working magnetic flux density increases overall. That is, the effective magnetic flux density of the whole can be increased by an amount corresponding to the reduced effective magnetic flux in the outer peripheral side region.
The directivity is better as the outer diameter of the diaphragm is reduced, and when the diaphragm is ring-shaped as in the present invention, the smaller the inner diameter is. A magnet plate that combines a basic area magnet and an outer peripheral area magnet on the outer peripheral side in this way can form a high effective magnetic flux density distribution in the area of the acoustic diaphragm having a reduced outer diameter and inner diameter. It is possible to manufacture mid-range and high-range speakers with good characteristics and efficiency.
(6) In the electroacoustic transducer of the present invention using the magnet plate having the center region magnet, when the electroacoustic transducer of the present invention having the outer peripheral region magnet is also arranged coaxially, the center The area magnet can also be used as the outer peripheral area magnet in the electroacoustic transducer at the center. Also, in this case, the area that does not require a high effective working magnetic flux density is widened on the inner peripheral side of the acoustic diaphragm, so that the effective working magnetic flux in the inner peripheral side area is distributed by the central area magnet and effectively The working magnetic flux density can be increased. As described above, when the coaxial speaker is used, the features of the center region magnet can be utilized to the maximum extent.

Here, the magnet plate of three-direction magnetization has a central region magnet on the center side of the basic region magnet and an outer peripheral region magnet on the outer peripheral side. In addition, the two-direction magnetized magnet plate is a plate in which only the center region magnet is installed on the center side of the basic region magnet, or a plate in which only the outer region magnet is installed on the outer periphery side of the basic region magnet.
The effective magnetization angle at which the contribution of the effective magnetic flux to the conductor of the acoustic diaphragm increases in each of these partial areas is divided into two cases depending on the magnetization direction of the basic area magnet. The magnetization direction of the basic region magnet is such that a component parallel to the vibration surface of the acoustic diaphragm is magnetized so as to be in the radial direction of the acoustic diaphragm. There is a case.
When the magnetization direction component of the basic region magnet is a radial direction toward the center side, the magnetization direction of the center region magnet is a component parallel to the central axis of the acoustic diaphragm. In the magnetization direction of the outer peripheral area magnet, the component parallel to the central axis of the acoustic diaphragm is the rearward direction of the acoustic diaphragm (hereinafter referred to as “rear direction of the central axis”). Further, when the magnetization direction component of the basic region magnet is the radial direction toward the outer peripheral side, the magnetization direction of the central region magnet is a component parallel to the central axis of the acoustic diaphragm, and the rear direction of the central axis. As for the magnetization direction, the component parallel to the central axis of the acoustic diaphragm is the forward direction of the central axis.

In addition, regarding the magnetization angle that maximizes the contribution of the effective magnetic flux to the conductor of the acoustic diaphragm in the three types of partial regions, the distance between the acoustic diaphragm and the magnet plate, the region of the conductor portion of the acoustic diaphragm, It changes depending on the proportion of each partial area of the magnet plate. Accordingly, the magnetization angle of each partial region is appropriately determined by grasping the distribution state of the effective effective magnetic flux density and the utilization efficiency of the magnetic flux based on these conditions.
The magnetization angle of the basic region magnet should be in the range of −30 degrees to 70 degrees when the radial direction toward the center of the acoustic diaphragm is 0 degree and the forward direction of the acoustic diaphragm is a positive direction. Is preferred.
Regarding the distribution of the effective magnetic flux on the conductor of the acoustic diaphragm formed by the basic area magnet, the distance between the acoustic diaphragm and the basic area magnet, the area of the conductor part of the acoustic diaphragm, the position and size of the basic area magnet It depends on. The basic area magnet is often installed in a wide area behind the conductor portion of the acoustic diaphragm, and the distribution of effective magnetic flux density in such an area will be described.
When the magnetization angle of the basic region magnet is about 10 degrees, a region having a high effective magnetic flux density is located approximately in the middle between the inner peripheral side and the outer peripheral side of the acoustic diaphragm. As the magnetization angle becomes smaller, the region having a higher effective working magnetic flux density moves toward the inner peripheral side of the acoustic diaphragm. However, when it becomes smaller than −30 degrees, the effective working magnetic flux density decreases as a whole, and the magnetic flux There is a tendency for the efficiency of use to decline significantly. Further, as the magnetization angle of the basic region magnet becomes larger than 10 degrees, the region having a high effective working magnetic flux density moves toward the outer peripheral side of the acoustic diaphragm. There is a tendency that the efficiency of use of magnetic flux decreases and the utilization efficiency of magnetic flux decreases.

Compared with the conventional case where the magnetization angle is 90 degrees (for example, Patent Document 2), the values obtained by integrating the effective working magnetic flux in the conductor of the acoustic diaphragm in the region of the conductor are each part in the magnet plate with two-direction magnetization. When the magnetization angle of the region is optimized, it reaches 2.5 times, and even when the magnetization angle of the basic region magnet is 70 degrees, it is about 1.7 times. Thus, by optimizing the magnetization angle of the basic region magnet, the utilization efficiency of the magnetic flux can be dramatically increased.
Also, the distribution of the effective magnetic flux density at each position of the acoustic diaphragm can be easily uniformed because the distribution state can be adjusted by changing the magnetization angle compared to the conventional case where the magnetization angle is 90 degrees and constant. Thus, a uniform driving force can be obtained on the entire surface of the diaphragm.
There are cases where one magnet plate is disposed behind the acoustic diaphragm, and two magnet plates are disposed opposite the front and rear sides of the acoustic diaphragm. The structure in which two magnet plates are arranged on both the front and rear sides of the acoustic diaphragm can efficiently increase the effective working magnetic flux density, so that the amount of magnets used can be reduced. Furthermore, since the difference in effective magnetic flux density with respect to the vibration in the front-rear direction of the acoustic diaphragm is reduced, the distortion caused by the difference is also reduced. Therefore, if the influence on the acoustic characteristics can be ignored even if the magnet plate is arranged in front of the acoustic diaphragm, it is better to adopt a structure in which two plates are arranged.
In addition, even when one magnet plate is disposed behind the acoustic diaphragm, by placing either one or both of the central region magnet and the outer peripheral region magnet in front of the acoustic diaphragm, the magnet plate in front of the acoustic diaphragm The effective magnetic flux density can be increased by reducing the influence on the acoustic characteristics.
When a magnet is also arranged in front of the acoustic diaphragm, the magnetization directions of the partial regions are generally arranged so as to face each other with respect to the vibration surface of the acoustic diaphragm. In order to improve the uniformity of the magnetic flux distribution in the vicinity, it may not be symmetrical.

The center area magnet is the center part of the magnet plate and is small, so it is often composed of a single ring or columnar magnet. However, when the magnetization direction is difficult to magnetize or there is a gap in the center area magnet. For example, when a sound passage hole is provided, a plurality of small magnets are used in combination. Since the basic region magnet has many radial components in the magnetization direction, it is difficult to magnetize if it is composed of one magnet. Further, since the gap provided in the basic area magnet is often used as a sound passage hole, the basic area magnet is often configured by separating a plurality of small magnets from each other. The outer peripheral area magnet is often composed of a single ring-shaped magnet when an acoustic diaphragm with a small diameter is used, but the area becomes considerably large when an acoustic diaphragm with a large diameter is used. It is preferable to configure the magnets in combination.
A permanent magnet such as a neodymium or Sm—Co rare earth magnet, a ferrite magnet, or an alnico magnet can be used as the material for such a magnet plate.

The acoustic diaphragm is formed by winding an insulated conductor made of aluminum, copper, silver, gold or the like in a spiral shape and bonding the conductors with a synthetic resin adhesive such as silicone resin, epoxy, or cyanoacrylate. A planar coil is used, and a multilayer planar coil in which a plurality of planar coils are bonded together to increase the strength is also used.
In addition, a conductor such as aluminum, copper, silver, gold, etc. on the surface of a thin substrate made of synthetic resin such as polyimide, polyethylene, polycarbonate, etc., which is a non-magnetic material, ceramic, synthetic fiber, wood fiber, or a composite material thereof. A circuit in which a circuit is formed as a spiral pattern by vapor deposition means, etching means, or the like can be used.

  In the loudspeaker, it is necessary to reduce the diameter of the diaphragm in order to prevent deterioration of directivity as the band to be reproduced becomes higher. A microphone or the like uses a diaphragm having a small diameter. If the area of the diaphragm is reduced, the efficiency and sensitivity will decrease, so it is necessary to increase the effective magnetic flux density. However, the magnet plate with three-direction magnetization concentrates the effective magnetic flux even on such a small diameter diaphragm. The efficiency and sensitivity can be improved effectively by increasing the effective magnetic flux density.

In a two-direction magnetization magnet plate having a three-direction magnetization magnet plate or a center region magnet, a magnetic force directed toward the opposite (rear) side of the acoustic diaphragm acts on the center side of the basic region magnet by the center region magnet. Further, in a two-direction magnetization magnet plate having a three-direction magnetization magnet plate or an outer peripheral area magnet, a magnetic force directed toward the opposite (rear) side of the acoustic diaphragm acts on the outer peripheral side of the basic area magnet by the outer peripheral area magnet.
As a result, when a strong magnet such as a neodymium magnet is used in the three-direction magnetized magnet plate, the basic area magnet can be fixed simply by being received by a frame provided behind the electroacoustic transducer. Therefore, even if a magnet with a strong magnetic force such as a neodymium magnet is adopted, the center area magnet and the outer area area magnet are fixed by sandwiching the frame between the center area magnet and the outer area area magnet. A magnet plate can be formed by simply setting a basic area magnet between the outer peripheral area magnet and the outer peripheral area magnet.
Similarly, in the case of a magnet plate that is bi-directionally magnetized, if the center region magnet is provided, the center side of the basic region magnet is provided behind the electroacoustic transducer. It can be fixed simply by receiving it with a frame.
By adopting the center area magnet and the outer area magnet, the effective magnetic flux density can be dramatically increased as compared with the radially magnetized magnet plate. Can be inherited. Therefore, while maintaining an effective magnetic flux density close to that of a magnet plate with an optimum magnetization angle, there is no problem in manufacturing like a magnet plate with an optimum magnetization angle even when a high-performance magnet is used, such as a speaker, headphones, microphone, etc. The production of the magnetic plate becomes extremely easy.

The electroacoustic transducer according to claim 2 is a magnet plate that is formed in a disc shape or a ring shape as a whole, and a planar coil that is formed in parallel with the magnet plate and is formed by winding a conductor in a spiral shape. An electroacoustic transducer having a disk-like or ring-like acoustic diaphragm comprising: a component parallel to a vibration surface of the acoustic diaphragm in the magnetization direction of each partial region of the magnet plate; In addition to the basic region magnet magnetized so as to be in the radial direction toward the outer periphery of the diaphragm, a component parallel to the central axis of the acoustic diaphragm is located behind the acoustic diaphragm at a position on the center side of the basic region magnet. Magnetized so that the component parallel to the central axis of the acoustic diaphragm is in the forward direction of the acoustic diaphragm at a position on the outer peripheral side of the central area magnet or the basic area magnet magnetized so as to be in the direction At least the outer peripheral area magnet Re or has Configurations that includes one.
This configuration has the same effect as that of the first aspect.

  Here, the electroacoustic transducer according to claim 2 is the electroacoustic transducer according to claim 1, wherein the magnetization direction in each partial region of the magnet plate of three-direction magnetization and the magnet plate of two-direction magnetization is reversed by 180 degrees. Since the rest is as described in claim 1, the description thereof is omitted.

Invention of Claim 3 is the electroacoustic transducer of Claim 1 or 2, Comprising: The said center area | region magnet or the side opposite to the side in which the said acoustic diaphragm is installed in the said magnet plate A frame that fixes at least one of the outer peripheral area magnets, and the basic area magnet is fixed to the frame by a magnetic force that the central area magnet or the outer peripheral area magnet presses the basic area magnet toward the frame side; It has the composition which is.
With this configuration, in addition to the operation obtained in the first or second aspect, the following operation can be obtained.
(1) In a magnet plate with three-direction magnetization and a magnet plate with two-direction magnetization, a magnetic force that presses against the frame behind the electroacoustic transducer acts on the center side of the basic area magnet by the center area magnet. Moreover, the magnetic force which presses against the flame | frame behind an electroacoustic transducer with respect to the outer peripheral side of a basic area magnet by an outer peripheral area magnet acts. When a high-performance neodymium magnet or the like is used as the magnet, these magnetic forces become very strong and the basic area magnet is fixed.
By utilizing such a magnetic force, a new fixing means such as a special frame for fixing each of the basic area magnets becomes unnecessary. Thereby, the limited area | region of a magnet can be utilized effectively and the utilization efficiency of magnetic flux can be improved. Moreover, since it is not necessary to make the shape of the magnet a special shape for the fixing means, the processing is simple and the manufacturing process can be greatly simplified.
(2) Generally, the acoustic diaphragm is attached by fixing edge portions on the center side and the outer peripheral side of the magnet plate. When the bolt that fixes the center region magnet is removed after the magnet plate is assembled, the center region magnet jumps forward from the magnet plate, but does not pop out completely and stops at about half. Since the center area magnet does not completely pop out, the center side of the acoustic diaphragm can be attached at the same time by setting the acoustic diaphragm as it is and tightening together with the bolts to which the center area magnet is attached. Since such a method can be taken in a limited space in the center, it is very advantageous in acoustic performance and manufacturing process.

  Here, when using a magnet such as ferrite, which has a weak magnetic influence, a resin such as acrylic can be suitably used. However, a magnet such as neodymium breaks due to its large magnetic force, so aluminum, copper, etc. A non-magnetic metal such as is preferably used. Also, as a means to fix the magnet to the frame, if the magnetic force is acting in the direction that the magnet is removed from the frame, fixing with adhesive etc. is quite difficult, and the means to fix by sandwiching between the frame and frame, frame and bolt Is easy and reliable.

When assembling a magnet plate having three-direction magnetization, first, the central area magnet and the outer peripheral area magnet are fixed to the frame behind the electroacoustic transducer. This operation can be easily performed in a state where the influence of the magnetic force is weak because the central region magnet and the outer peripheral region magnet are separated from each other. Next, when the basic area magnet is brought to a position in front of the magnet plate between the central area magnet and the outer peripheral area magnet, the basic area magnet is pulled in the rear direction of the magnet plate by the magnetic force. By being received by the frame behind the converter, it is fixed in place. When the basic area magnet is composed of a plurality of small magnets, a magnet plate is completed by repeating this work for the number of magnets.
As described above, each process of manufacturing the magnet plate is very simple, and it should be noted that a neodymium magnet or the like has a strong magnetic force acting on the basic region magnet, and is therefore only set gently to prevent cracking. Also in the design, it is unnecessary to consider the structure for the fixing means and the influence of the magnetic force in the middle of the assembly, so that the mass productivity is excellent.

The invention according to claim 4 is the electroacoustic transducer according to claim 1 or 2, wherein the vibration of the acoustic diaphragm is arranged at a position symmetrical to the central region magnet with the acoustic diaphragm interposed therebetween. A front center region magnet magnetized in a direction symmetrical to the magnetization direction of the center region magnet with respect to the surface, or a position symmetrical to the outer periphery region magnet across the acoustic diaphragm It has the structure provided with at least any one of the front outer periphery area | region magnet magnetized in the direction symmetrical with the magnetization direction of the said outer periphery area | region magnet with respect to a vibration surface.
With this configuration, in addition to the operation obtained in the first or second aspect, the following operation can be obtained.
(1) By placing a front center region magnet and a front outer region magnet magnetized in a plane-symmetrical direction so as to face the center region magnet and the outer region magnet with the acoustic diaphragm interposed therebetween, effective on the acoustic diaphragm The working magnetic flux density can be further increased. Moreover, since the portions on the center side and the outer periphery side in front of the acoustic diaphragm that have little influence on sound can be used, the effective magnetic flux density can be increased without impairing the acoustic characteristics, and the efficiency can be easily improved. it can.

  Here, the front center area magnet and the front outer peripheral area magnet in front of the acoustic diaphragm can improve the acoustic characteristics by changing their shapes. For example, by devising the shape, the front center area magnet can be used as a diffuser that can improve the directivity, and the front outer area magnet can also be used as a horn.

The invention according to claim 5 is the electroacoustic transducer according to claim 4, wherein the electroacoustic transducer is disposed at a position symmetrical to the basic area magnet with the acoustic diaphragm interposed therebetween, on the vibration surface of the acoustic diaphragm. On the other hand, it has the structure provided with the front basic region magnet magnetized in the direction symmetrical to the magnetization direction of the basic region magnet.
With this configuration, in addition to the operation obtained in the fourth aspect, the following operation can be obtained.
(1) By installing a front basic area magnet magnetized in a plane-symmetrical direction so as to face the basic area magnet on the front side of the acoustic diaphragm, the amount of magnets can be increased at a position close to the acoustic diaphragm. Therefore, the effective working magnetic flux density can be increased efficiently.
(2) In addition to the magnet plate behind the acoustic diaphragm, in addition to the front center area magnet and the front outer peripheral area magnet magnetized in a plane symmetric with the rear magnet board, the front basic area magnet is placed in front of the acoustic diaphragm. By installing, the effective magnetic flux density at each position of the vibrating acoustic diaphragm can be made symmetric in the vibration direction with respect to the installed position of the acoustic diaphragm. Thereby, the distortion which arises by the difference of the height of an effective action magnetic flux density in the vibration direction of an acoustic diaphragm can be suppressed.

Here, the front basic region magnet can be disposed in front of the acoustic diaphragm as a front magnet plate having at least one of a front center region magnet and a front outer peripheral region magnet.
At this time, the magnetization direction in each partial region of the magnet plate disposed behind the acoustic diaphragm and the magnetization direction in each partial region of the front magnet plate disposed in front of the acoustic diaphragm are opposed to each other ( It is plane-symmetric with respect to the vibration surface of the acoustic diaphragm). Therefore, the front center region magnet or the front can be simply disposed by placing a front frame for fixing the front center region magnet or the front outer peripheral region magnet in front of the front magnet plate (the side opposite to the side where the acoustic diaphragm is installed). The front basic area magnet is fixed to the front frame by the magnetic force of the outer peripheral area magnet pressing the front basic area magnet toward the front frame.

The invention according to claim 6 is the electroacoustic transducer according to claim 1 or 2, wherein at least one of the basic area magnet, the outer peripheral area magnet, and the central area magnet of the magnet plate is: It has the structure provided with the sound passage hole which lets the sound which generate | occur | produces outside or inside pass.
With this configuration, in addition to the operation obtained in the first or second aspect, the following operation can be obtained.
(1) Since many sound passage holes for allowing sound to pass through are formed in the magnet plate, sound generated in the entire area of the acoustic diaphragm is emitted without interfering with each other in a speaker, a headphone, etc. For example, an electric signal with less distortion can be obtained by reducing interference of sound received from outside.
Here, the sound passage hole is an opening formed in each partial region of the magnet plate. As a method of providing a sound passage hole, there are a method of directly forming an opening in a magnet, a method of using a gap provided between adjacent magnets, and the like. The sound passage hole is formed mainly with the central axis of the hole perpendicular to the vibration surface of the acoustic diaphragm, but the central axis is inclined or the inner wall of the hole is expanded with respect to the sound traveling direction. By providing an inclined portion having a diameter or a reduced diameter, the acoustic characteristics can be improved and the sound collecting property can be enhanced.
Sound passage holes can be provided in the partial areas of the basic area magnet, outer circumference area magnet, and center area magnet. However, since these influence the distribution of effective magnetic flux density and the efficiency of magnetic flux utilization, grasp these conditions. While determining the position and ratio to the magnet.

The invention according to claim 7 has a configuration in which a plurality of electroacoustic transducers according to claim 1 or 2 are concentrically arranged with different sizes.
With this configuration, in addition to the operation obtained in the first or second aspect, the following operation can be obtained.
(1) Since independent electroacoustic transducers having different diaphragm sizes and acoustic characteristics can be configured concentrically (coaxially) to form a composite electroacoustic transducer as a whole, the radiation area of sound, etc. These can be properly arranged integrally according to the application conditions, and an electroacoustic transducer having excellent acoustic characteristics can be obtained. For example, a combination type electroacoustic transducer having excellent frequency characteristics and directivity can be easily configured by combining electroacoustic transducers with different reproduction frequency bands such as for high sound range, medium sound range, and low sound range. .
(2) Since electroacoustic transducers having different acoustic characteristics can be coaxially arranged to form a composite type, an electroacoustic transducer having excellent phase characteristics can be provided.

As described above, according to the electroacoustic transducer of the present invention, the following advantageous effects can be obtained.
According to invention of Claim 1, it has the following effects.
(1) By using a magnet plate with three-direction magnetization or a magnet plate with two-direction magnetization, it is possible to effectively generate a radial magnetic flux along the vibration surface of the acoustic diaphragm, and to have a high effective magnetic flux density. A wide area can be secured. As a result, the effective magnetic flux density is higher than that of the magnet plate magnetized in the radial direction, the efficiency of the insufficient speaker can be improved, and the Q (resonance sharpness) of the low frequency speaker that has been excessively increased. ) Can be reduced, and an electroacoustic transducer excellent in practicality can be provided.
(2) The magnet plate of three-direction magnetization distributes the effective working magnetic flux in the outer peripheral side region and the inner peripheral side region not used in the acoustic diaphragm in a useful region used in the acoustic diaphragm so that the total effective working magnetic flux density is increased. Can be increased. Further, by further narrowing the area to be used, it is possible to intensively increase the effective magnetic flux density, and it is possible to provide an electroacoustic transducer excellent in efficiency that can effectively increase efficiency and sensitivity.
(3) A magnet plate having a two-direction magnetization can narrow a magnet region with respect to a region having a high effective magnetic flux density as compared with a magnet plate having a three-direction magnetization. Therefore, when the sound generated from the back side of the acoustic diaphragm is emitted to the back of the electroacoustic transducer, the obstacles due to the magnet are reduced, and the influence on the vibration of the acoustic diaphragm is reduced, thereby preventing the deterioration of the acoustic characteristics. Thereby, the electroacoustic transducer excellent in reliability can be provided.
(4) Compared with a radially magnetized magnet plate, a bilaterally magnetized magnet plate in which a basic region magnet and a central region magnet are combined concentrates the effective magnetic flux in the inner peripheral region on a specific region, and thus the overall effective operation. Magnetic flux density can be increased. Compared with a magnet plate with three-direction magnetization, a region with a high effective magnetic flux density can be expanded to the outer peripheral side, which is optimal for electroacoustic conversion when the acoustic diaphragm is designed to have a large diameter like a low-frequency speaker. Can be provided.
(5) Compared with a radially magnetized magnet plate, a bilaterally magnetized magnet plate in which a basic region magnet and an outer peripheral region magnet are combined concentrates the effective working magnetic flux in the outer peripheral region on a specific region, so that the total effective working magnetic flux The density can be increased. In addition, the outer diameter and inner diameter of the ring-shaped acoustic diaphragm can be reduced, and an electroacoustic transducer suitable as a mid-range speaker and a high-range speaker having good directivity and efficiency can be provided. .
(6) In the electroacoustic transducer of the present invention using the magnet plate having the center region magnet, when the electroacoustic transducer of the present invention having the outer peripheral region magnet is also arranged coaxially, the center The area magnet can also be used as the outer peripheral area magnet in the electroacoustic transducer at the center. Therefore, the amount of magnets used can be reduced, and the limited magnet area can be used effectively. Moreover, the effective magnetic flux density can be increased by distributing the effective magnetic flux density in the inner peripheral region not used in the acoustic diaphragm by the central region magnet, so that the feature of the central region magnet can be utilized to the maximum. An electroacoustic transducer with excellent efficiency can be provided.

  According to invention of Claim 2, it has the same effect as Claim 1.

According to invention of Claim 3, in addition to the effect of Claim 1 or 2, it has the following effects.
(1) With a magnet plate with three-direction magnetization and a magnet plate with two-direction magnetization, the center region magnet and the outer peripheral region magnet are pressed against the center and outer peripheral sides of the basic region magnet against the frame behind the electroacoustic transducer. Magnetic force works. Therefore, in particular, by using a high-performance neodymium magnet or the like as the magnet, the basic region magnet can be fixed using a very strong magnetic force. Thereby, since a new fixing means becomes unnecessary, an electroacoustic transducer excellent in workability and mass productivity can be provided.
(2) Since a special frame or the like for fixing each of the magnets is unnecessary, a limited magnet area can be used effectively, and the use efficiency of magnetic flux can be increased. Moreover, since it is not necessary to process the shape of the magnet into a special shape for the fixing means, an electroacoustic transducer having a simple manufacturing process and excellent mass productivity can be provided.
(3) Since the center side of the acoustic diaphragm can be attached at the same time using the bolts to which the center region magnet is attached, the limited space at the center can be used effectively. Furthermore, since the manufacturing process is simple, it is excellent in mass productivity and can provide a high-quality electroacoustic transducer with a simplified structure.

According to invention of Claim 4, in addition to the effect of Claim 1 or 2, it has the following effects.
(1) By arranging the front center region magnet and the front outer region magnet so as to face the center region magnet and the outer region magnet with the acoustic diaphragm sandwiched therebetween, The effective magnetic flux density on the acoustic diaphragm can be increased without impairing the acoustic characteristics by utilizing the portion on the outer peripheral side. Thereby, the electroacoustic transducer which can raise efficiency easily can be provided.

According to invention of Claim 5, in addition to the effect of Claim 4, it has the following effects.
(1) By disposing the front basic area magnet so as to face the basic area magnet across the acoustic diaphragm, the effective magnetic flux density can be efficiently increased by increasing the magnet amount at a position close to the acoustic diaphragm. . Thereby, the electroacoustic transducer excellent in the efficiency which can raise efficiency efficiently with a small magnet amount can be provided.
(2) The effective action magnetic flux density at each position of the vibrating acoustic diaphragm can be made symmetric in the vibration direction with respect to the installation position of the acoustic diaphragm. As a result, it is possible to suppress distortion caused by the difference in effective magnetic flux density in the vibration direction of the acoustic diaphragm, and provide an electroacoustic transducer suitable as a low-frequency speaker in which the amplitude of the acoustic diaphragm increases can do.

According to invention of Claim 6, in addition to the effect of Claim 1 or 2, it has the following effects.
(1) Since many sound passage holes for allowing sound to pass through are formed in the magnet plate, sound generated in the entire area of the acoustic diaphragm is emitted without interfering with each other in a speaker, a headphone, etc. For example, an electric signal with less distortion can be obtained by reducing interference of sound received from outside. Thereby, the electroacoustic transducer excellent in the acoustic characteristic can be provided.

According to invention of Claim 7, in addition to the effect of Claim 1 or 2, it has the following effects.
(1) Since independent electroacoustic transducers having different diaphragm sizes and acoustic characteristics can be configured concentrically (coaxially) to form a composite electroacoustic transducer as a whole, the radiation area of sound, etc. According to the application conditions, it is possible to properly arrange them integrally and provide an electroacoustic transducer having excellent acoustic characteristics.
(2) Since the electroacoustic transducers with different reproduction frequency bands such as for the high range, the mid range, and the low range can be easily combined coaxially, a composite type electroacoustic having excellent frequency characteristics and directivity characteristics A transducer can be provided.
(3) Electroacoustic transducers having different acoustic characteristics can be coaxially arranged to form a composite type, and an electroacoustic transducer having excellent phase characteristics can be provided.

1 is an exploded perspective view of an electroacoustic transducer according to Embodiment 1. FIG. 1 is a schematic cross-sectional end view of the main part of the electroacoustic transducer of the first embodiment. Main section schematic cross-sectional end view of electroacoustic transducer of Embodiment 2 Schematic cross-sectional end view of the main part of the electroacoustic transducer of Embodiment 3 Main section schematic cross-sectional end view of electroacoustic transducer of Embodiment 4 The figure which showed the effective action magnetic flux density with respect to the radial direction of the acoustic diaphragm of the electroacoustic transducer of Embodiment 1.

Explanation of symbols

10, 20, 30, 40, 50, 60 Electroacoustic transducers 11, 21, 41, 51, 61 Magnet plates 11a, 21a, 41a, 51a, 61a Central area magnets 11b, 21b, 41b, 51b, 61b Basic area magnets 11b ', 21b', 41b ', 51b', 51c ', 61b', 61c ', 67b', 67c 'Small magnet 11c, 51c, 61c Outer peripheral area magnet 11d, 13h, 14a, 14c, 14d, 15a, 16b, 66b Insertion holes 12b, 14b, 22b, 24b, 42b, 52b, 52c, 54b, 54d, 62b, 62c, 64b, 68b, 68c, 69b Sound passage holes 13a, 23a, 43a, 53a, 63a Acoustic diaphragms 13b, 23b , 43b, 53b, 63b Inner peripheral side support part 13c, 23c, 43c, 53c, 63c Outer peripheral side support part 13d, 13 e, 23d, 23e Lead line 13f, 13g, 23f, 23g Terminal portion 14, 24, 54, 64 Rear frame 15, 25a, 55a Center frame 15b, 25b, 55d, 65c Outer frame 15c, 16a Female thread portion 16, 26, 56, 66 Main frame 17a, 17b, 17c, 27a, 27b, 27c, 57a, 57b, 57c, 57d, 70a, 70b Bolt 18, 28, 58a, 58b, 71a, 71b Nut 21d Front center area magnet 21e Front outer circumference area Magnet 22c, 54e, 54f Sound absorbing material 25c Central support frame 25d Outer periphery support frame 51d Groove 54a Sound insulation plate 55b Intermediate support frame 55c Intermediate fixed frame 55e Spacer 65a Rear center frame 65b Front center frame 67 Front magnet plate 67a Square central region magnets 67b front base area magnet 67c front outer circumference area magnet 69 the front frame

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.
(Embodiment 1)
FIG. 1 is an exploded perspective view of the electroacoustic transducer of the first embodiment, and FIG. 2 is a schematic cross-sectional end view of the main part of the electroacoustic transducer of the first embodiment.
1 and 2, 10 is the electroacoustic transducer of the first embodiment, 11 is a magnet plate of the electroacoustic transducer 10 that is generally configured in a disc shape, and 11 a is a ring-like shape in a partial region of the magnet plate 11. A central area magnet using a neodymium magnet, 11b is a basic area magnet composed of 12 trapezoidal small magnets 11b 'using a neodymium magnet in a partial area of the magnet plate 11, and 11c is a partial area of the magnet plate 11. An outer peripheral area magnet using a ring-shaped neodymium magnet, 11d is an insertion hole for a bolt 17a provided at the center of the central area magnet 11a, and 12b is formed between adjacent trapezoidal small magnets 11b 'in the basic area magnet 11b. 12 sound passage holes, 13a is an acoustic diaphragm having a planar coil formed by winding a conductor in a spiral shape, and is installed in front of the magnet plate 11, and 13b is an acoustic vibration. 13a is an inner peripheral side support portion that elastically supports and vibrates an acoustic diaphragm 13a that is connected to the inner peripheral side of 13a, and 13c is an outer peripheral side that elastically supports the acoustic diaphragm 13a that is connected to the outer peripheral side of the acoustic diaphragm 13a and vibrates. A support part, 13d is a lead wire on the inner peripheral side of the conductor wound spirally in the acoustic diaphragm 13a, 13e is a lead wire on the outer peripheral side of the conductor spirally wound in the acoustic diaphragm 13a, and 13f is A terminal portion (see FIG. 2) attached to the center side of a rear frame 14 to be described later and connected to a lead wire 13d (see FIG. 2), and a terminal portion 13g attached to the outer peripheral side of the rear frame 14 and connected to a lead wire 13e (see FIG. 2). ), 13h is an insertion hole for a bolt 17a provided at the center of the inner peripheral support portion 13b, 14 is a rear frame of the electroacoustic transducer 10 formed of a nonmagnetic material that supports the magnet plate 11 at the rear, and 14a is a rear An insertion hole for a bolt 17 a provided in the center of the side frame 14, 14 b is a sound passage hole provided with a plurality of openings in the rear frame 14, and 14 c is provided at four locations inside the outer periphery of the rear frame 14. Bolts 17b insertion holes, 14d are four bolt 17c insertion holes provided on the outer peripheral side of the rear frame 14, and 15 is a non-magnetic ring-shaped central frame installed in front of the center area magnet 11a. 15a is an insertion hole for a bolt 17a provided in the center of the central frame 15, 15b is a non-magnetic body and is formed in a substantially L-shaped cross section, and is installed on the outer peripheral side of the outer peripheral area magnet 11c. 15c is a bolt 17b. In order to attach the outer peripheral frame 15b, four female screw portions 16 are provided on the electroacoustic transducer 10 and the electroacoustic transducer 16 is formed of a nonmagnetic material that supports the entire electroacoustic transducer 10 at the front. The main frame 16 of the device 10a is provided with four female screw portions on the main frame 16 for attaching the bolts 17c, and 16b is provided on the outer periphery of the main frame 16 for attaching the entire electroacoustic transducer 10 to the enclosure. 18 is a nut made of a non-magnetic material (see FIG. 2), 17a is screwed into the nut 18 and is located at the center of the acoustic diaphragm 13a. 11a, the central frame 15, and a non-magnetic bolt for fixing the inner support 13b of the acoustic diaphragm 13a, 17b a non-magnetic bolt for connecting the rear frame 14 and the outer frame 15b, and 17c an outer periphery. The non-magnetic bolts connect the rear frame 14 and the main frame 16.
In FIG. 2, for convenience of explanation, the right side of the center line shows a cross section cut at a position passing through the female screw portion 16a of the main frame 16, and the left side of the center line passes through the insertion hole 16b of the main frame 16. A cross section cut at a position is shown.

The center area magnet 11a inserts the bolt 17a into the insertion hole 13h of the inner peripheral side support portion 13b, the insertion hole 15a of the center frame 15, the insertion hole 11d of the center area magnet 11a, and the insertion hole 14a of the rear frame 14, and the nut 18 It is fixed by screwing together.
The outer peripheral area magnet 11c is sandwiched between the rear frame 14 and the outer peripheral frame 15b, and is fixed by inserting a bolt 17b into the insertion hole 14c of the rear frame 14 and screwing it into the female screw portion 15c of the outer peripheral frame 15b. .
In the present embodiment, the outer peripheral area magnet 11c is composed of one ring-shaped permanent magnet. However, when the diameter becomes large and handling becomes difficult, a ring-shaped outer peripheral area magnet is combined with a plurality of small magnets. 11c may be used.

Since a plurality of small magnets 11b ′ constituting the basic region magnet 11b are fixed by acting strongly on the rear frame 14 between the central region magnet 11a and the outer peripheral region magnet 11c, No other special fixing means are used. In addition, in order to prevent a position shift, you may apply | coat an adhesive agent auxiliary. Since the basic area magnet 11b is pressed against the rear frame 14, the small magnets 11b ′ constituting the basic area magnet 11b do not fall back backward in the sound passage holes 14b, which are a plurality of openings provided in the rear frame 14. It has a shape like this.
In addition, although the shape of several small magnet 11b 'which comprises the basic region magnet 11b is made into the trapezoid shape where the inner peripheral side is thin and the outer peripheral side is thick, the ratio of the upper base and the lower base can be selected suitably. Moreover, it can also form in hexagonal shape etc. other than trapezoid shape. Such a method is used as a means for changing the distribution state of the magnet portion in the magnet plate 11 to make the effective magnetic flux density of the acoustic diaphragm 13a uniform in the radial direction.

On the inner peripheral side of the acoustic diaphragm 13a, a connected inner peripheral side support portion 13b is sandwiched and fixed between the bolt 17a and the central frame 15. Further, the outer peripheral side of the acoustic diaphragm 13 a is fixed with the connected outer peripheral side support portion 13 c sandwiched between the outer peripheral frame 15 b and the main frame 16. The outer peripheral side support portion 13c is sandwiched when the space between the main frame 16 and the rear frame 14 is fixed by a bolt 17c.
When the bolt 17a is removed, the center area magnet 11a jumps forward from the magnet plate 11, but does not completely jump out and stops in half, so that the plurality of small magnets 11b 'constituting the basic area magnet 11b are separated. It will not be. In the removal of the acoustic diaphragm 13a, if the bolt 17a is removed with the main frame 16 removed, the disassembly work can be easily performed. Moreover, the attachment of the acoustic diaphragm 13a can be easily performed in the reverse order of the removal, and the assembly workability is excellent.
The central frame 15 and the outer peripheral frame 15b also serve as a spacer that keeps a distance from each other so that the acoustic diaphragm 13a that vibrates in the front-rear direction does not collide with the magnet plate 11.

The thin ring-shaped acoustic diaphragm 13a uses a single planar coil in which a conductor made of an insulated copper clad / aluminum wire is wound in one direction in a spiral shape and the wires are joined with a silicone resin. A multi-layer planar coil in which a plurality of sheets are bonded can also be used. In this case, all the currents flowing through the planar coil are in the same direction. As the material of the planar coil, insulated aluminum, copper or the like may be used, and the coils may be bonded with a synthetic resin adhesive such as epoxy or cyanoacrylate.
The terminal portion 13f and the terminal portion 13g to which driving current is supplied from the outside are connected to the inner peripheral side lead wire 13d and the outer peripheral side lead wire 13e, respectively. In the microphone or the like, the acoustic diaphragm 13a is vibrated by sound, and an electromotive force generated in the conductor is taken out as an electric signal from the terminal portions 13f and 13g.
The sound passage hole 12b utilizes a gap provided between the trapezoidal small magnets 11b ′ constituting the basic area magnet 11b, and electroacoustic conversion of sound generated from the back side of the acoustic diaphragm 13a together with the sound passage hole 14b. It discharges to the back of the vessel 10.

As the inner peripheral side support portion 13b and the outer peripheral side support portion 13c, those having a suspension function that are formed in a sheet shape and elastically connect the central frame 15, the outer peripheral frame 15b, and the acoustic diaphragm 13a are used. When the low sound range is reproduced, the acoustic diaphragm 13a has a large amplitude in the front-rear direction, and therefore, the one formed with a collar portion that causes large elastic deformation is used. In this case, the central frame 15 and the outer peripheral frame 15b are used. Are designed so that the distance between the acoustic diaphragm 13a and the magnet plate 11 is wide.
As the inner peripheral side support part 13b and the outer peripheral side support part 13c, in addition to those made of synthetic resin made of urethane resin such as silicone resin or urethane foam, those made of rubber or the like are also used. In addition, a woven fabric, a nonwoven fabric, or the like formed of synthetic resin fibers such as polyester fibers, or a composite sheet obtained by impregnating a synthetic resin such as a silicone resin or a urethane resin may be used. In addition, in order to maintain the shape of a collar part satisfactorily, what was formed with the multilayer composite sheet etc. which laminated | stacked and bonded together the said composite sheet is also used.
Since the other manufacturing method of the acoustic diaphragm 13a is the same as the conventional method (for example, refer to Japanese Patent No. 3612319 or Japanese Patent Application No. 2005-159862), detailed description thereof is omitted.

In FIG. 2, the direction of the NS pole is described according to the type of each partial region in the magnet plate 11. In the partial region of the magnet plate 11, the magnetization direction of the basic region magnet 11b is such that the magnetization angle θ with respect to the vibration surface of the acoustic diaphragm 13a is 0 degrees (parallel to the vibration surface of the acoustic diaphragm 13a), and the outer peripheral side of the acoustic diaphragm 13a. The radial direction from the center toward the center. The magnetization angle θ of the center region magnet 11a is set to +90 degrees, that is, the front direction of the center axis of the acoustic diaphragm 13a. Further, the magnetization angle θ of the outer peripheral area magnet 11c is −90 degrees, that is, the rear direction of the central axis of the acoustic diaphragm 13a.
Here, a neodymium magnet is used as the material of the magnet plate 11. One ring-shaped magnet having an outer diameter of 20 mm, an inner diameter of 6 mm, and a thickness of 10 mm is used as the central area magnet 11a, and one ring-shaped magnet having an outer diameter of 80 mm, an inner diameter of 60 mm, and a thickness of 10 mm is used as the outer peripheral area magnet 11c. Yes. Further, twelve pieces having a trapezoidal shape of 4 mm in the upper base, 11 mm in the lower base and 19 mm in height and 10 mm in thickness are used as the small magnets 11b ′ constituting the basic area magnet 11b. The gap between the trapezoidal small magnets 11b ′ constituting the basic area magnet 11b is a sound passage hole 12b. As a result, the proportion of the magnet area in the basic area magnet 11b is 68%. Therefore, the proportion of the space as the sound passage hole 12b is 32%.
The interval between the acoustic diaphragm 13a and the magnet plate 11 is 3 mm.

Next, the magnetic force in the backward direction of the central axis of the acoustic diaphragm 13a acting on the basic area magnet 11b, that is, the magnetic force pressing the basic area magnet 11b against the rear frame 14 of the electroacoustic transducer 10 will be described.
In general, in the magnetization direction of the basic region magnet 11b, when the magnetization angle θ is 0 degree and the radial direction is toward the center of the acoustic diaphragm 13a, the magnetization angle θ is 90 degrees for the center region magnet 11a. It has been found by various examinations and experiments that the magnetic force that is sometimes pressed against the rear frame 14 becomes the largest. Further, it has been found that the magnetic force that presses against the rear frame 14 becomes the largest when the magnetization angle θ is set to −90 degrees for the outer peripheral area magnet 11c.
Therefore, the magnetization angle employed in the central region magnet 11a and the outer peripheral region magnet 11c of the first embodiment is a magnetization angle at which the magnetic force that presses against the rear frame 14 against the basic region magnet 11b is the largest. In the first embodiment, neodymium is adopted as the material of the magnet, and the basic region magnet 11b is fixed by utilizing a large magnetic force that is pressed against the rear frame 14 of the electroacoustic transducer 10.

As another method of fixing the trapezoidal small magnet 11b ′ constituting the basic area magnet 11b, a method of adhering to the central area magnet 11a or the outer peripheral area magnet 11c with an adhesive or the like without using the rear frame 14 is also conceivable. . However, this method requires attention when a neodymium magnet is adopted as the material of the magnet because the magnetic force is strong and may be lost, and there is also a problem with stability. In addition, a method of providing a frame or the like for fixing the basic region magnet 11b between the magnet plate 11 and the acoustic diaphragm 13a is also conceivable. However, the effective magnetic flux density is increased because the gap between the magnet plate 11 and the acoustic diaphragm 13a is widened. Tends to decrease somewhat.
In the first embodiment, as described above, the height and uniformity of the effective working magnetic flux density in the acoustic diaphragm 13a, the size of the region having a high effective working magnetic flux density, the ease of magnetization during magnet manufacture, the basic region magnet The magnetization angle and size of the basic region magnet 11b, the central region magnet 11a, and the outer peripheral region magnet 11c are determined by considering the direction and strength of the magnetic force acting on 11b.

According to the electroacoustic transducer 10 in Embodiment 1 of the present invention as described above, the following operation is obtained.
(1) Since the magnetization angle θ of the central region magnet 11a on the central side in the magnet plate 11 is +90 degrees and the magnetization angle θ of the outer peripheral region magnet 11c on the outer peripheral side is −90 degrees, a magnet plate with radial magnetization is used. Compared with the case of using the acoustic diaphragm 13a having a general size, the effective magnetic flux density in the conductor can be dramatically increased. Thereby, in the electroacoustic transducer 10 using the acoustic diaphragm 13a having the characteristic of very high sound quality, a speaker, a headphone, a microphone and the like excellent in efficiency and sensitivity can be easily manufactured.
(2) Since the magnetization angle θ of the central region magnet 11a on the center side in the magnet plate 11 is +90 degrees and the magnetization angle θ of the outer peripheral region magnet 11c on the outer periphery side is −90 degrees, the rear frame is placed on the basic region magnet 11b. The large magnetic force which presses against 14 works. Therefore, the basic area magnet 11b can be fixed without using any special means only by being received by the rear frame 14, and it is necessary to provide a frame or the like for fixing the basic area magnet 11b between the magnet plate 11 and the acoustic vibration plate 13a. Therefore, the effective magnetic flux density does not decrease.
(3) A special shape for fixing the magnet to the central region magnet 11a, the basic region magnet 11b, and the outer peripheral region magnet 11c constituting the magnet plate 11 is not required.
(4) The direction of magnetization of the center region magnet 11a and the outer peripheral region magnet 11c formed in a ring shape is the axial direction, and the direction of magnetization of the trapezoidal small magnet 11b ′ constituting the basic region magnet 11b is from the bottom. The direction is toward the top. In this way, magnetization is very simple because the magnetization directions are all simple.

Note that the magnetization direction of the partial region described in the first embodiment may be configured such that the magnetic plate is completely reversed, that is, the magnetization direction of all the partial regions is rotated by 180 degrees. If the poles of the drive current supplied to the terminal portions 13f and 13g are reversed, common performance can be obtained.
Moreover, although the neodymium magnet was used as a material of a magnet, another magnet can also be used and what has a high coercive force like Sm-Co etc. is especially suitable. Although effective working magnetic flux density and magnetic force are reduced, ferrite or the like can be used.

(Embodiment 2)
FIG. 3 is a schematic cross-sectional end view of a main part of the electroacoustic transducer of the second embodiment.
In FIG. 3, 20 is the electroacoustic transducer of the second embodiment, 21 is a magnet plate of the electroacoustic transducer 20 configured in a disk shape, and 21 a is a ring-shaped neodymium magnet in a partial region of the magnet plate 21. The central region magnet used, 21b is a basic region magnet composed of a plurality of trapezoidal small magnets 21b ′ using neodymium magnets in a partial region of the magnet plate 21, and 21d is installed at the front center of the acoustic diaphragm 23a. A front center region magnet using a neodymium magnet formed in a ring shape with a hemispherical round front portion, 21e is a front outer region magnet using a ring-shaped neodymium magnet installed on the front outer periphery of the acoustic diaphragm 23a, and 22b is A sound-absorbing material 22c is formed between adjacent trapezoidal small magnets 21b 'in the basic region magnet 21b, and a sound-absorbing material made of glass wool installed at the rear of the sound-passing hole 22b. 23a is an acoustic diaphragm disposed in front of the magnet plate 21 having a planar coil formed by winding a conductor in a spiral shape, and 23b is elastically coupled to the acoustic diaphragm 23a that is connected to the inner peripheral side of the acoustic diaphragm 23a and vibrates. The inner peripheral side support portion 23c that supports the outer peripheral side of the acoustic diaphragm 23a is elastically supported by the outer peripheral side support portion 23c that is connected to the outer peripheral side of the acoustic diaphragm 23a, and 23d is wound in a spiral shape on the acoustic diaphragm 23a. A lead wire on the inner periphery side of the conductor, 23e is a lead wire on the outer periphery side of the conductor wound in a spiral shape on the acoustic diaphragm 23a, 23f is attached to the center side of the rear frame 24 described later, and a lead wire 23d is connected. 23g is a terminal portion attached to the outer peripheral side of the rear frame 24 and connected to the lead wire 23e, and 24 is a rear frame of the electroacoustic transducer 20 formed of a non-magnetic material that supports the magnet plate 21 on the rear side. A frame 24b is a sound passage hole formed by forming a plurality of openings in the rear frame 24, 25a is a non-magnetic ring-shaped central frame installed in front of the central area magnet 21a, and 25b is non-magnetic. 25c is a non-magnetic body-shaped outer peripheral frame installed in front of the outer peripheral side of the basic area magnet 21b, a central support frame formed in a ring shape with a non-magnetic body and disposed behind the front central area magnet 21d, and 25d is a non-magnetic body An outer peripheral support frame formed in a ring shape and installed behind the front outer peripheral area magnet 21e, 26 is a main frame of the electroacoustic transducer 20 formed of a nonmagnetic material that supports the entire electroacoustic transducer 20 in the front, 27a Is a non-magnetic bolt that is screwed into the female thread portion of the central frame 25a and fixes the central region magnet 21a to the rear frame 24 at the central portion of the acoustic diaphragm 23a, 7b is a non-magnetic bolt that connects the rear frame 24 and the outer frame 25b, 27c is a non-magnetic bolt that connects the main frame 26 and the rear frame 24, and 28 is screwed into the bolt 27a and is screwed into the acoustic diaphragm 23a. This is a nut made of a non-magnetic material that fixes the inner peripheral side support portion 23b, the center support frame 25c, and the front center region magnet 21d to the center frame 25a.
In FIG. 3, for convenience of explanation, a cross section cut at a position passing through the small magnet 21b ′ of the basic area magnet 21b is shown on the right side of the center line as in FIG. 2, and sound is passed on the left side of the center line. A cross section cut at a position passing through the hole 22b is shown.

The outer peripheral side of the plurality of trapezoidal small magnets 21b ′ constituting the basic area magnet 21b is sandwiched between the rear frame 24 and the outer peripheral frame 25b, and is fixed by screwing the bolts 27b into the female screw portions of the outer peripheral frame 25b. Has been. The center side of the basic area magnet 21b is strongly pressed against and fixed to the rear frame 24 by the magnetic force acting between the basic area magnet 21a and other fixing means are not used.
The bolt 27c is screwed into a female thread portion formed on the main frame 26 to connect the rear frame 24 and the main frame 26. Further, between the rear frame 24 and the main frame 26, the magnet plate 21 and the outer frame are connected. 25b, the outer peripheral side support portion 23c of the acoustic diaphragm 23a, the outer peripheral support frame 25d, and the front outer peripheral area magnet 21e are sandwiched to fix them.

For the central frame 25a, the outer peripheral frame 25b, the central support frame 25c, and the outer peripheral support frame 25d, the acoustic diaphragm 23a that vibrates in the front-rear direction, the inner peripheral support part 23b, and the outer peripheral support part 23c are provided on the rear magnet plate. 21, the front center region magnet 21d and the front outer peripheral region magnet 21e also serve as a spacer that keeps a distance so as not to collide.
Since the acoustic diaphragm 23a, the lead wires 23d and 23e, and the terminal portions 23f and 23g are the same as the acoustic diaphragm 13a, the lead wires 13d and 13e, and the terminal portions 13f and 13g in the first embodiment, description thereof is omitted.
The gap provided between the trapezoidal small magnets 21b 'constituting the basic area magnet 21b is used as a sound passage hole 22b, and the sound generated from the back side of the acoustic diaphragm 23a is absorbed by the sound passage hole 22b and the sound absorption hole. It is discharged to the back of the electroacoustic transducer 20 through the material 22c and the sound passage hole 24b. In addition, since a gap is formed between the trapezoidal small magnets 21b ′ constituting the basic area magnet 21b in the portion on the side surface side of the electroacoustic transducer 20, the outer frame 25b and the rear side via the sound passage hole 22b. Sound is also emitted from between the frame 24.
As the inner periphery side support portion 23b and the outer periphery side support portion 23c, the same ones as the inner periphery side support portion 13b and the outer periphery side support portion 13c in the first embodiment are preferably used. The inner peripheral support 23b is between the central frame 25a and the central support frame 25c and the acoustic diaphragm 23a, and the outer peripheral support 23c is between the outer peripheral frame 25b, the outer peripheral support frame 25d and the acoustic diaphragm 23a. It has a suspension function that elastically connects between them.

In FIG. 3, the direction of the NS pole is described according to the type of each partial region in the magnet plate 21. In each partial region, the magnetization direction of the basic region magnet 21b is parallel to the vibration surface of the acoustic diaphragm 23a and is in the radial direction toward the center of the acoustic diaphragm 23a. The magnetization direction of the center region magnet 21a is set to the front direction of the center axis of the acoustic diaphragm 23a.
The front center area magnet 21d has a magnetization direction that faces the center area magnet 21a, that is, the direction behind the center axis of the acoustic diaphragm 23a. The front outer peripheral area magnet 21e has a magnetization direction that is opposite to the front central area magnet 21d, that is, the front direction of the central axis of the acoustic diaphragm 23a.

In Embodiment 1, the effective magnetic flux is applied to the acoustic diaphragm 13a by installing the central region magnet 11a and the peripheral region magnet 11c, which are partial regions having different magnetization directions, on the central side and the outer peripheral side of the basic region magnet 11b. I was able to concentrate.
In the second embodiment, a very high effective magnetic flux is concentrated on the acoustic diaphragm 23a by a slightly different method.
The magnetic flux distribution on the acoustic diaphragm 23a formed by the center area magnet 21a is the same size as the center area magnet 21a and the same size as the center area magnet 21a with respect to the vibration surface of the acoustic diaphragm 23a. The exact same result is obtained. Accordingly, the front central region magnet 21d facing the central region magnet 21a also has an effect of concentrating the effective magnetic flux in a narrow range like the central region magnet 21a. Thus, the front center region magnet 21d is installed for the purpose of enhancing the effect exerted by the center region magnet 21a.

Similarly, the front outer peripheral area magnet 21e has an effect of concentrating effective magnetic flux in a narrow range. Therefore, although no magnet is installed on the outer peripheral side of the basic region magnet 21b, the same operation is secured by installing the front outer peripheral region magnet 21e in front of the outer peripheral side of the magnet plate 21 instead. In this way, in the second embodiment, a very high effective magnetic flux is concentrated on the acoustic diaphragm 23a even if the outer peripheral magnet of the basic area magnet 21b is eliminated.
The effective magnetic flux density can be increased by installing a magnet with a magnetization direction that is plane-symmetric with respect to the vibration surface of the acoustic diaphragm 23a at the symmetrical position with the acoustic diaphragm 23a sandwiched between the basic region magnets 21b. However, it is not installed because the effect on the acoustic characteristics increases when the frequency to be reproduced increases.

In the second embodiment, a structure that reduces the influence of the sound passage hole on the sound is employed. That is, the outer peripheral region magnet is not installed on the outer periphery of the basic region magnet 21b, and the outer peripheral frame 25b and the rear frame 24 are used by utilizing the sound passage hole 22b on the side (outer periphery) of the electroacoustic transducer 20. Sound is also emitted from between. When sound is emitted in this manner, the sound passage hole becomes shallower, and the ratio of the sound passage hole to the opening increases, so the influence on the vibration of the acoustic diaphragm 23a is reduced. Furthermore, since the types of depths of the sound passage holes are increased, it is possible to prevent the influence on the vibration of the acoustic diaphragm 23a from being biased to a specific frequency.
Further, the space formed between the acoustic diaphragm 23a and the magnet plate 21 and the sound passage hole 22b may cause the resonance of the acoustic diaphragm 23a to a specific frequency. In the second embodiment, a sound absorbing material 22c is provided behind the sound passage hole 22b in order to reduce the reflection of sound that causes the resonance. Glass wool is installed as the sound absorbing material 22c so that a certain amount of sound passes through the sound absorbing material 22c and is emitted to the rear of the electroacoustic transducer 20 through the sound passage hole 24b. The same effect can be obtained by applying a material having a large internal loss, such as silicone, to the part facing the space that causes resonance in the magnet plate 21 and the outer peripheral frame 25b, etc. to prevent reflection of sound.
In this way, the sound absorbing material 22c is installed in the sound passage hole 22b and the sound is emitted also from the side surface of the electroacoustic transducer 20, thereby reducing the influence of the sound passage hole on the sound.
Moreover, the ring-shaped front center region magnet 21d has a front portion rounded into a spherical shape. This is for avoiding the influence of a horn-like portion in the sound path, which causes peaks and valleys in the frequency characteristics. Similarly, the frequency characteristics may be flattened by rounding the corners of the sound passage for the front outer peripheral magnet 21e.

Next, the magnetic force in the rearward direction of the central axis of the acoustic diaphragm 23a acting on the basic area magnet 21b, that is, the magnetic force pressed against the rear frame 24 will be described.
In general, when the magnetization direction of the basic area magnet 21b is parallel to the vibration surface of the acoustic diaphragm 23a and is in the radial direction toward the center of the acoustic diaphragm 23a, the magnetization direction of the center area magnet 21a is in front of the central axis. In the case of the direction, the magnetic force pressing the basic area magnet 21b against the rear frame 24 becomes the largest. Therefore, the magnetization direction employed in the center region magnet 21a of the second embodiment is a magnetization angle at which the magnetic force pressing the rear region 24 against the basic region magnet 21b is the largest. In the second embodiment, neodymium is adopted as the material of the magnet, and the center side of the basic region magnet 21b is fixed by using such a magnetic force that strongly presses against the rear frame 24.
In the second embodiment, as described above, the influence of the sound passage hole, the height and uniformity of the effective working magnetic flux density in the acoustic diaphragm 23a, the ease of magnetization at the time of magnet manufacture, the fixing method of the basic area magnet 21b, etc. In consideration, the magnetization angle, size, and configuration method of the magnet plate 21, the front center area magnet 21d, and the front outer area magnet 21e are determined.

According to the electroacoustic transducer 20 in the second embodiment of the present invention as described above, the following operation is obtained in addition to the operation described in the first embodiment.
(1) The effective magnetic flux is further concentrated on the acoustic diaphragm 23a by installing the front center area magnet 21d on the front center side of the acoustic diaphragm 23a and setting the magnetization direction to face the center area magnet 21a. To increase the density.
(2) By eliminating the magnet on the outer peripheral side of the basic area magnet 21b, a sound passing hole is formed between the small magnets 21b ′ constituting the basic area magnet 21b in the portion (outer periphery) on the side surface side of the electroacoustic transducer 20. An opening to be 22b can be formed. Since sound is also emitted from the side surface of the electroacoustic transducer 20 through this opening, the depth of the sound passage hole 22b can be reduced to reduce the effect on the vibration of the acoustic diaphragm 23a. Further, it is possible to prevent the depth of the sound passage hole 22b from increasing and the influence on the vibration of the acoustic diaphragm 23a from being biased to a specific frequency.
(3) The outer peripheral magnet of the basic region magnet 21b is abolished by installing the front outer peripheral region magnet 21e on the front outer peripheral side of the acoustic diaphragm 23a and setting the magnetization direction in a direction substantially opposite to the front central region magnet 21d. Can be compensated for.
(4) The front portion of the ring-shaped front center region magnet 21d is formed in a hemispherical round shape, thereby reducing the number of square portions in the portion that becomes the sound path. As a result, it is possible to flatten the frequency characteristic by eliminating the cause of peaks and valleys in the frequency characteristic.
(5) Since the outer peripheral side of the basic area magnet 21b is sandwiched between the rear frame 24 and the outer peripheral frame 25b and tightened with the bolts 27b, it can be fixed securely. Compared to the case where the basic area magnet 21b is fixed only by the magnetic force pressed against the rear frame 24, it can be securely fixed even when the magnetic force is weakened due to the influence of the material of the magnet, etc. Excellent.
(6) Since the sound absorbing material 22c is installed in the sound passage hole 22b, the reflection of the sound in the space can be reduced and the resonance of the acoustic diaphragm 23a biased to a specific frequency can be reduced.

(Embodiment 3)
FIG. 4 is a schematic cross-sectional end view of the main part of the electroacoustic transducer of the third embodiment.
In FIG. 4, reference numeral 30 denotes a composite type of Embodiment 3 in which a high-frequency electroacoustic transducer 40 and a low-frequency electroacoustic transducer 50 that are formed independently of each other are arranged concentrically. The electroacoustic transducer 41 is a high-frequency electroacoustic transducer 40 magnet plate, which is configured in a disc shape, and 41a is a high region using a ring-shaped neodymium magnet in a partial region of the high-frequency magnet plate 41. A central region magnet for the region, 41b is a basic region magnet for the high region composed of a plurality of trapezoidal small magnets 41b ′ using neodymium magnets in a partial region of the magnet plate 41 for the high region, and 42b is a high region High-frequency sound passage hole 43a formed between adjacent trapezoidal small magnets 41b 'in the basic region magnet 41b, and a high-frequency magnet 43a having a planar coil in which a conductor is spirally wound Electroacoustic conversion for high frequencies installed in front of the plate 41 Forty acoustic diaphragms 43b are connected to the inner circumference side of the high frequency acoustic diaphragm 43a and elastically support the vibrating high frequency acoustic diaphragm 43a. The low-frequency electroacoustic transducer 51 is connected to the outer peripheral side of the acoustic vibration plate 43a and elastically supports the vibrating high-frequency acoustic vibration plate 43a. 50 magnet plates, 51a is a central region magnet using a ring-shaped neodymium magnet in a partial region of the low-frequency magnet plate 51, and 51b is a plurality of neodymium magnets in a partial region of the low-frequency magnet plate 51. A basic area magnet 51c composed of a trapezoidal small magnet 51b ', and an outer peripheral area magnet 51c composed of a plurality of rectangular parallelepiped small magnets 51c' using neodymium magnets in a partial area of the low-frequency magnet plate 51. , 51d is an outer peripheral area magnet 51c. The groove part formed in the outer peripheral surface of each small magnet 51c 'which comprises, 52b is a low-pass sound passage hole formed between the trapezoidal small magnets 51b' adjacent to the low-pass basic area magnet 51b, 52c is an outer peripheral sound passage hole formed between adjacent rectangular parallelepiped small magnets 51c ′ in the low-frequency outer peripheral region magnet 51c, and 53a has a flat coil in which a conductor is wound in a spiral shape. The low-frequency acoustic diaphragm 53b installed in front of the magnetic plate 51 for the low frequency band is connected to the inner peripheral side of the low-frequency acoustic diaphragm 53a, so that the vibrating low-frequency acoustic diaphragm 53a is elastic. An inner peripheral side support portion 53c supported on the outer peripheral side is connected to an outer peripheral side of the low-frequency acoustic diaphragm 53a, and an outer peripheral side support portion 54 elastically supports the vibrating low-frequency acoustic diaphragm 53a. Nonmagnetic material that supports the magnet plate 41 and the low-frequency magnet plate 51 at the rear The rear frame 54a of the electroacoustic transducer 30 is formed of a non-magnetic material in a disc shape, and is attached to the rear of the electroacoustic transducer 40 for high frequencies. , 54b is a low-frequency sound passage hole provided in the rear frame 54 by forming a plurality of openings behind the low-frequency basic area magnet 51b, and 54d is a high-frequency basic area magnet 41b in the rear frame 54. A high-frequency sound passage hole 54e formed by forming a plurality of openings at the rear, 54e is a rear sound-absorbing material made of glass wool installed between the high-frequency electroacoustic transducer 40 and the sound insulation plate 54a, 54f Is a ring-shaped support sound-absorbing material made of glass wool sandwiched between a high-frequency acoustic vibration plate 43a and a high-frequency magnet plate 41, and 55a is a non-magnetic material formed in a thin ring shape for high-frequency use. In front of the central region magnet 41a A central frame 55b is formed in a ring shape with a non-magnetic material and is provided in front of the low-frequency central region magnet 51a, and 55c is formed in a ring shape with a non-magnetic material. The intermediate fixed frame 55d installed in front of the outer peripheral side support portion 43c of the acoustic diaphragm 43a for use and the inner periphery side support portion 53b of the acoustic diaphragm 53a for low range is formed of a non-magnetic material and is used for the low range. An outer peripheral frame 55e is installed on the outer peripheral side of each small magnet 51c ′ of the outer peripheral area magnet 51c and fitted in the groove 51d, and 55e is an outer peripheral part of the low-range magnet plate 51, which will be described later. The non-magnetic spacer 56 for keeping the distance between the electroacoustic transducers 30 is a main frame of the electroacoustic transducer 30 formed of a non-magnetic material that supports the entire electroacoustic transducer 30 in front of the low-frequency magnet plate 51. , 57 a is screwed into a nut 58a made of a non-magnetic material and is located at the center of the high-frequency acoustic diaphragm 43a at the inner peripheral side support portion 43b of the high-frequency acoustic diaphragm 43a, the central frame 55a, and the high-frequency acoustic diaphragm 43a. The center region magnet 41a, a non-magnetic bolt 57b for fixing the rear frame 54, and 57b are screwed into a female thread portion formed on the circumference of the intermediate support frame 55b, and the center region magnet for the low region is attached to the rear frame 54. A non-magnetic bolt 57c for fixing 51a is screwed into a female screw portion formed on the circumference of the outer peripheral frame 55d, and a non-magnetic bolt for fixing the outer peripheral area magnet 51c for low frequency to the rear frame 54. , 57d is a non-magnetic bolt that connects the rear frame 54 and the main frame 56 at the outer peripheral portion, 58b is screwed into the bolt 57b, and the outer peripheral side support portion 43c of the high-frequency acoustic diaphragm 43a is low. Acoustic for area Rotation plate 53a, which is a non-magnetic material made of a nut fixed to the intermediate support frame 55b of the inner peripheral-side supporting portion 53b with an intermediate fixed frame 55c of.
In FIG. 4, for convenience of explanation, a cross section cut at a position passing through the small magnet 51 b ′ of the basic region magnet 51 b for low frequency is shown on the right side of the center line, and for the low frequency side on the left side of the center line. The cross section cut | disconnected in the position which passes the sound passage hole 52b is shown.

A through hole is provided in the center region magnet 51a for the low region so as to pass the bolt 57b. Further, the plurality of small magnets 51c ′ constituting the low-frequency outer peripheral area magnet 51c have a rectangular parallelepiped shape and have a groove portion. Bolts 57c are formed on the periphery of the outer peripheral frame 55d through the outer peripheral frame 55d. It is fixed to the rear frame 54 by being screwed into the female thread portion. The rear frame 54 is provided with a groove so as to embed a plurality of small magnets 51c ′ constituting the low-frequency outer peripheral region magnet 51c. When the small magnets 51c ′ are combined in this way, they repel each other. The whole is prevented from being decomposed by the magnetic force.
The rear frame 54 and the main frame 56 are connected by a bolt 57d, and the distance between the rear frame 54 and the main frame 56 is kept constant at the outer peripheral portion by the spacer 55e. The outer peripheral side support portion 53 c of the low-frequency acoustic diaphragm 53 a is fixed by bonding the outer peripheral portion to the inner peripheral side rear surface of the main frame 56.
For the central frame 55a and the intermediate support frame 55b, a high-frequency acoustic vibration plate 43a and a low-frequency acoustic vibration plate 53a that vibrate in the front-rear direction are replaced by a rear high-frequency magnet plate 41 and a low-frequency magnet. It also serves as a spacer that provides a gap so as not to collide with the plate 51. Further, since the amplitude of the low-frequency acoustic diaphragm 53a for reproducing the low frequency range is large, the low-frequency magnet plate 51 is rearward compared to the high-frequency magnet plate 41 in order to widen the interval. It is installed in a staggered manner. The center region magnet 51a for the low band is designed to protrude slightly forward from the basic region magnet 51b for the low band and to be close to the acoustic diaphragm 53a for the low band, so that the effective magnetic flux density and magnetic flux can be increased. The use efficiency of is increased. In the case of installing in this way, the length extending forward is determined within a range in which the inner peripheral side support portion 53b does not hit the central region magnet 51a for low frequency even when the acoustic diaphragm 53a has the maximum amplitude.
The high-frequency acoustic diaphragm 43a sandwiches the supporting sound-absorbing material 54f together with the high-frequency magnet plate 41. That is, the supporting sound absorbing material 54f is brought into contact with the entire back surface of the high frequency acoustic vibrating plate 43a, whereby the high frequency acoustic vibrating plate 43a is elastically and uniformly supported by the supporting sound absorbing material 54f. . In this way, not only the sound absorbing function but also the function of braking the high frequency acoustic diaphragm 43a is provided to the supporting sound absorbing material 54f, so that even small divided vibrations are not generated. In such a case, the material of the sound-absorbing material 54f for supporting is not only glass wool but also non-woven fabric using polypropylene resin, polyethylene resin, polyester resin, etc., and foamed resin made of polyethylene resin, polyurethane resin, etc. It may be the one with

The gap provided between the trapezoidal small magnets 41b ′ constituting the high-frequency basic area magnet 41b is used as a high-frequency sound passage hole 42b, and is from the back side of the high-frequency acoustic diaphragm 43a. The generated sound is emitted to the rear of the high-frequency electroacoustic transducer 40 together with the high-frequency sound passage hole 54d. In addition, a gap provided between the trapezoidal small magnets 51b ′ constituting the low-frequency basic area magnet 51b is also used as the low-frequency sound passage hole 52b, and the low-frequency acoustic diaphragm 53a The sound generated from the back side is emitted to the rear of the low-frequency electroacoustic transducer 50 together with the low-frequency sound passage hole 54b.
Regarding the low-frequency basic area magnet 51b and the low-frequency outer peripheral area magnet 51c, the low-frequency sound passage hole 52b and the outer peripheral sound passage hole 52c formed between the small magnets 51b ′ and 51c ′. It is installed so that the positions of In this way, the sound generated from the back side of the low-frequency acoustic diaphragm 53a is routed through the low-frequency sound passage hole 52b and the outer sound-passing hole 52c, so that the space between the outer peripheral frame 55d and the rear frame 54 is reduced. Can also be released from.
In the third embodiment, the sound generated from the back side of the low-frequency acoustic diaphragm 53a is also applied to the side surface of the low-frequency electroacoustic transducer 50 between the main frame 56 and the low-frequency outer peripheral region magnet 51c. Released to the side. That is, by sandwiching the spacer 55e between the main frame 56 and the rear frame 54, a space is secured between the main frame 56 and the low-frequency outer peripheral region magnet 51c, and the side surface side of the low-frequency electroacoustic transducer 50 More sound is released to the outside.
In this case, the installation position of the main frame 56 can secure a wide space for sound emission as far as possible with respect to the low-frequency acoustic diaphragm 53a. Therefore, in the third embodiment, the flange portion of the outer peripheral side support portion 53c of the low-frequency acoustic diaphragm 53a is fixed at the foremost portion of the flange portion so as to be connected to the main frame 56 at a position as far forward as possible. is doing. Such a method is very effective as a measure for increasing the number of openings serving as sound passage holes and reducing the influence of the sound passage holes on the acoustic characteristics.
The sound generated from the back side of the low-frequency acoustic diaphragm 53a and the sound generated from the back side of the high-frequency acoustic diaphragm 43a are prevented from interfering with each other by providing a sound insulating plate 54a. That is, by adhering the sound insulating plate 54a to the rear frame 54 so as to cover the high frequency electroacoustic transducer 40, the mutual sound is completely blocked to prevent interference. The sound generated from the back side of the high-frequency acoustic diaphragm 43a is absorbed by the rear sound-absorbing material 54e installed between the high-frequency electroacoustic transducer 40 and the sound insulating plate 54a.
The thin ring-shaped high-frequency acoustic diaphragm 43a is the same as the acoustic diaphragm 13a of the first embodiment. A thin ring-shaped acoustic diaphragm 53a for a low frequency band is formed by winding a conductor made of insulated copper clad / aluminum wire in one direction in a spiral shape and bonding two planar coils joined with silicone resin. Used. By bonding two planar coils, the mechanical strength is ensured so that the low-frequency acoustic diaphragm 53a is not broken during low-frequency reproduction where the amplitude increases. Each planar coil is connected to a lead wire (not shown) as in the first and second embodiments, and is connected to a terminal portion (not shown) to which a drive current is supplied from the outside.

The composite electroacoustic transducer 30 of the third embodiment is coaxial with a high frequency electroacoustic transducer 40 for reproducing a high frequency range and a low frequency electroacoustic transducer 50 for reproducing a low frequency range. They are arranged in a concentric manner. Accordingly, the central axis of the high-frequency acoustic diaphragm 43a and the central axis of the low-frequency acoustic diaphragm 53a are common.
Since the amplitude is increased in the low-frequency acoustic diaphragm 53a, the inner peripheral side support portion 53b and the outer peripheral side support portion 53c are formed with flanges, but the high frequency acoustic diaphragm 43a is used. Then, since the amplitude does not increase, the inner periphery side support part 43b and the outer periphery side support part 43c are flat. As the inner peripheral side support part 43b and the outer peripheral side support part 43c, synthetic resin such as silicone resin or rubber is used. In order to increase mechanical strength, the inner peripheral side support portion 53b and the outer peripheral side support portion 53c that support the low-frequency acoustic diaphragm 53a with increased amplitude are formed of synthetic resin fibers such as polyester fibers. A composite sheet in which a woven fabric is impregnated with a synthetic resin such as a silicone resin is used. Moreover, in order to maintain the shape of the ridge well, a multilayer composite sheet or the like in which the composite sheets are stacked and bonded together is used.

In FIG. 4, the direction of the NS pole is described according to the type of each partial region of the magnet. In each partial region, the magnetization direction of the high-frequency basic region magnet 41b is parallel to the vibration surface of the high-frequency acoustic diaphragm 43a and is in the radial direction toward the center of the high-frequency acoustic diaphragm 43a. . The magnetization direction of the high-frequency central region magnet 41a is set to the front direction of the central axis of the high-frequency acoustic diaphragm 43a.
In addition, the magnetization direction of the low-frequency central region magnet 51a is set to the rear of the central axis of the high-frequency acoustic diaphragm 43a. The magnetization direction of the low-frequency basic region magnet 51b is generally the direction facing the high-frequency basic region magnet 41b. Accordingly, the magnetization direction of the low-frequency basic area magnet 51b is set to be opposite to the magnetization direction of the high-frequency basic area magnet 41b, that is, the radial direction toward the outer periphery of the low-frequency acoustic diaphragm 53a. ing. The magnetization direction of the low-frequency outer peripheral area magnet 51c is determined with respect to the low-frequency basic area magnet 51b, and is the front direction of the central axis of the low-frequency acoustic diaphragm 53a.

In the first embodiment, with respect to the basic region magnet 11b in which the magnetization direction is the radial direction of the acoustic diaphragm, by installing the central region magnet 11a and the outer peripheral region magnet 11c having different magnetization directions on the central side and the outer peripheral side, It was possible to increase the density by concentrating the effective magnetic flux. In the third embodiment, the same means is used to form a very high effective magnetic flux density. That is, for the low-frequency basic area magnet 51b, a low-frequency central area magnet 51a on the center side and a low-frequency outer peripheral area magnet 51c on the outer peripheral side are arranged. Further, for the high-frequency basic area magnet 41b, a high-frequency central area magnet 41a on the center side thereof is arranged.
In addition, although the central region magnet 51a for the low region of the magnet plate 51 is arranged on the outer peripheral side of the basic region magnet 41b for the high region, the central region magnet 51a for the low region is the basic region for the low region. In addition to the function as the central region magnet for the magnet 51b, it can also serve as the outer peripheral region magnet for the high-region basic region magnet 41b.

In the third embodiment, the effective working magnetic flux is concentrated on the conductor portions of the high-frequency acoustic diaphragm 43a and the low-frequency acoustic diaphragm 53a in this manner, thereby forming a distribution of high effective working magnetic flux density. A composite electroacoustic transducer 30 in which a high-frequency electroacoustic transducer 40 and a low-frequency electroacoustic transducer 50 are coaxially arranged is realized.
For the high-frequency basic area magnet 41b, the high-frequency basic area magnet 41b is affected by the magnetic force acting between the high-frequency central area magnet 41a and the low-frequency central area magnet 51a. Since the force which strongly presses the area magnet 41b against the rear frame 54 is fixed, other fixing means are not used. Further, the low band basic area magnet 51b is opposite in magnetization direction to the high band basic area magnet 41b, but is positioned on the low band central area magnet 51a and on the outer peripheral side. The magnetization direction of the low-frequency outer peripheral region magnet 51c is also opposite to the magnetization direction of the high-frequency central region magnet 41a and the low-frequency central region magnet 51a corresponding to the high-frequency peripheral region magnet 51a. Therefore, similarly, since the magnetic force which strongly presses against the rear frame 54 works and is fixed to the low-frequency basic region magnet 51b, no other fixing means is used.

According to the electroacoustic transducer 30 in the third embodiment of the present invention as described above, the following operation is obtained in addition to the operation described in the first or second embodiment.
(1) Since the high-frequency electroacoustic transducer 40 and the low-frequency electroacoustic transducer 50 of the present invention, each having a different size and acoustic characteristics, are combined to form a composite type, the high-frequency acoustic diaphragm 43a and the low-frequency acoustic diaphragm 53a can be integrally disposed appropriately according to application conditions such as a sound radiation area and weight. Thereby, the high-frequency electroacoustic transducer 40 and the low-frequency electroacoustic transducer 50 can be combined to take advantage of the characteristics of each frequency band, and a composite type electric power having excellent performance in all frequency bands. The acoustic transducer 30 can be configured.
(2) Since the high-frequency electroacoustic transducer 40 and the low-frequency electroacoustic transducer 50 are arranged concentrically (coaxially) to form a composite type, the composite type electric having excellent phase characteristics and directivity characteristics The acoustic transducer 30 can be obtained.
(3) The low-frequency central region magnet 51 a not only functions as a central-region magnet in the low-frequency magnet plate 51 but also functions as an outer peripheral region magnet in the high-frequency magnet plate 41. This makes it possible to effectively use a limited area of the magnet to increase the use efficiency of the magnetic flux and to eliminate the need for one type of partial area magnet, thereby reducing the amount of magnet used.
(4) Sound generated from the back side of the low-frequency acoustic diaphragm 53a can be emitted from between the main frame 56 and the low-frequency outer peripheral area magnet 51c. Therefore, the sound can be directly emitted to the outside without passing through the low-frequency magnet plate 51, and the influence of the sound passage hole on the vibration of the acoustic diaphragm 53a can be reduced.

(Embodiment 4)
FIG. 5 is a schematic cross-sectional end view of a main part of the electroacoustic transducer of the fourth embodiment.
In FIG. 5, 60 is the electroacoustic transducer of the fourth embodiment, 61 is the rear magnet plate of the electroacoustic transducer 60 configured in a disc shape, 61a is a ring shape in a partial region of the rear magnet plate 61 A rear central region magnet using a neodymium magnet, 61b is a rear basic region magnet composed of a plurality of trapezoidal small magnets 61b 'using neodymium magnets in a partial region of the rear magnet plate 61, and 61c is a rear A rear outer peripheral area magnet 62b composed of a plurality of rectangular parallelepiped small magnets 61c ′ using neodymium magnets in a partial area of the magnet plate 61, 62b is a trapezoidal small magnet 61b adjacent to the rear basic area magnet 61b. A sound passage hole 62c, a sound passage hole 62c formed between the adjacent rectangular parallelepiped small magnets 61c 'in the rear outer peripheral area magnet 61c, and 63a wind the conductor in a spiral shape. An acoustic diaphragm 63b having a rotated planar coil and installed in the middle part of the rear magnet plate 61 and the front magnet plate 67, which will be described later, is connected to the inner peripheral side of the acoustic diaphragm 63a and vibrates the acoustic diaphragm 63a. An inner peripheral side support portion that elastically supports, 63c is an outer peripheral side support portion that elastically supports the vibrating acoustic plate 63a connected to the outer peripheral side of the acoustic vibration plate 63a, and 64 is a non-supporting rear magnet plate 61 that is supported rearward. A rear frame of the electroacoustic transducer 60 made of a magnetic material, 64b is a sound passage hole provided by forming a plurality of openings in the rear frame 64, and 65a is a non-magnetic material formed in a ring shape and a central region in the rear A rear center frame installed in front of the magnet 61a (behind the acoustic diaphragm 63a), 65b is a non-magnetic ring-shaped front center frame installed in front of the acoustic diaphragm 63a, and 65c is a non-magnetic body. An outer peripheral frame 66 that is formed and installed in front of the outer peripheral side of the outer peripheral area magnet 61c, 66 is an electroacoustic transducer formed of a nonmagnetic material that supports the entire electroacoustic transducer 60 in front of the outer peripheral portion of the acoustic diaphragm 63a. 60 is a main frame, 66b is an insertion hole for bolts (not shown) provided at six locations on the outer periphery of the main frame 66 for attaching the entire electroacoustic transducer 60 to the enclosure, and 67 is configured as a disk. A front magnet plate of the electroacoustic transducer 60 disposed in the front part of the electroacoustic transducer 60, 67a is a front center region magnet using a ring-shaped neodymium magnet in a partial region of the front magnet plate 67, and 67b is a front magnet plate. A front basic area magnet composed of a plurality of trapezoidal small magnets 67 b ′ using neodymium magnets in 67 partial areas, and 67 c is a part of the front magnet plate 67. A front outer peripheral area magnet 68b composed of a plurality of small rectangular parallelepiped small magnets 67c 'using neodymium magnets in the region, and 68b is a sound passage formed between adjacent trapezoidal small magnets 67b' in the front basic area magnet 67b. A hole 68c is a sound passage hole formed between adjacent rectangular parallelepiped small magnets 67c 'in the front outer peripheral area magnet 67c, and 69 is an electroacoustic transducer 60 formed of a non-magnetic material that supports the front magnet plate 67 forward. The front frame 69b is a sound passage hole formed by forming a plurality of openings in the front frame 69, and 70a is screwed into a non-magnetic nut 71a and is attached to the rear frame 64 at the center of the acoustic diaphragm 63a. Rear center region magnet 61a, rear center frame 65a, inner peripheral support 63b of acoustic diaphragm 63a, front center frame 65b, front center region magnet 67a, front frame 69 A non-magnetic bolt 70b to be fixed is screwed into a non-magnetic nut 71b so that a rear frame 64, a rear outer region magnet 61c, an outer frame 65c, and an acoustic vibration plate 63a are formed on the outer periphery of the acoustic vibration plate 63a. This is a non-magnetic bolt that fixes the outer peripheral side support portion 63c, the main frame 66, the front outer peripheral area magnet 67c, and the front frame 69.
In FIG. 5, for convenience of explanation, the right side of the center line shows a cross section cut at a position passing through the small magnet 61b ′ of the rear basic area magnet 61b, and a sound passage hole 62b is shown on the left side of the center line. A cross section cut at a passing position is shown.

The rear center area magnet 61a and the front center area magnet 67a are provided with through holes for passing the bolts 70a. A plurality of rectangular parallelepiped small magnets 61c ′ constituting the rear outer peripheral area magnet 61c are sandwiched between the rear frame 64 and the outer peripheral frame 65c, and a plurality of rectangular parallelepiped small magnets 67c constituting the front outer peripheral area magnet 67c. 'Is sandwiched between the front frame 69 and the main frame 66 and is fixed by screwing the bolt 70b into the nut 71b.
The central area magnet 61a, the basic area magnet 61b, the outer peripheral area magnet 61c of the rear magnet plate 61, the front central area magnet 67a of the front magnet plate 67, the front basic area magnet 67b, and the front outer peripheral area magnet 67c each have an acoustic diaphragm 63a. They are arranged symmetrically with respect to each other, and their magnetization directions are also symmetrical (plane symmetry) with respect to the vibration surface of the acoustic diaphragm 63a.
The rear basic area magnet 61b is fixed by a force that is strongly pressed against the rear frame 64 by the magnetic force acting between the rear central area magnet 61a and the rear outer peripheral area magnet 61c. Similarly, the front basic area magnet 67b is fixed by a force that is strongly pressed against the front frame 69 by the magnetic force acting between the front central area magnet 67a and the front outer peripheral area magnet 67c.
The rear center frame 65a, the front center frame 65b, the outer frame 65c, and the main frame 66 are spacers that are spaced so that the acoustic diaphragm 63a that vibrates in the front-rear direction does not collide with the rear magnet plate 61 or the front magnet plate 67. It also plays a role.

A gap provided between the trapezoidal small magnets 61b ′ constituting the rear basic area magnet 61b is used as a sound passage hole 62b, and the sound generated from the back side of the acoustic diaphragm 63a is electrically combined with the sound passage hole 64b. It discharges behind the acoustic transducer 60. Further, with respect to the rear basic area magnet 61b and the rear outer peripheral area magnet 61c, the circumferential positions of the sound passage holes 62b and the sound passage holes 62c formed between the small magnets 61b ′ and the small magnets 61c ′. Are installed to match. Thus, the sound generated from the back side of the acoustic diaphragm 63a can be emitted from between the outer peripheral frame 65c and the rear frame 64 through the sound passage hole 62b and the sound passage hole 62c.
In the fourth embodiment, the sound generated from the front side of the acoustic diaphragm 63a is also emitted through the sound passage hole in the same manner as the sound generated from the back side. That is, the gap provided between the trapezoidal small magnets 67b ′ constituting the front basic area magnet 67b is used as the sound passage hole 68b, and the front of the electroacoustic transducer 60 together with the sound passage hole 69b of the front frame 69. Has been released. Also, the front basic area magnet 67b and the front outer peripheral area magnet 67c also have the same circumferential position of the sound passage hole 68b and the sound passage hole 68c formed between the small magnets 67b ′ and the small magnets 67c ′. The sound generated from the front side of the acoustic diaphragm 63a is emitted from between the main frame 66 and the front frame 69 by passing through the sound passage hole 68b and the sound passage hole 68c.

As the thin ring-shaped acoustic diaphragm 63a, a conductor made of an insulated copper clad / aluminum wire is wound in one direction in a spiral shape, and two planar coils bonded with silicone resin are bonded together. Note that a lead wire (not shown) is connected to the planar coil as in the first and second embodiments, and is connected to a terminal portion (not shown) to which a drive current is supplied from the outside.
Since the acoustic diaphragm 63a is often used for a low sound range in which the amplitude is increased, the inner peripheral side support portion 63b and the outer peripheral side support portion 63c are formed with flanges. The materials of the inner periphery side support portion 63b and the outer periphery side support portion 63c are the same as those described in the first embodiment, and thus description thereof is omitted.

In general, when a magnet plate is also provided at the front, in order to increase the effect, the magnetization direction of each partial region in the rear magnet plate 61 and the magnetization direction of each partial region in the front magnet plate 67 are the acoustic vibration plate 63a. In many cases, the directions are symmetrical with respect to the vibration plane. Therefore, the magnetization directions of the rear basic area magnet 61b and the front basic area magnet 67b are parallel to the vibration surface of the acoustic diaphragm 63a, and are in the radial direction toward the center of the acoustic diaphragm 63a. In addition, the magnetization direction of the rear central region magnet 61a is the front direction of the central axis of the acoustic vibration plate 63a, and the magnetization direction of the front central region magnet 67a is the rear direction of the central axis of the acoustic vibration plate 63a. The magnetization direction of the rear outer peripheral area magnet 61c is the rear direction of the central axis of the acoustic diaphragm 63a, and the magnetization direction of the front outer peripheral area magnet 67c is the front direction of the central axis of the acoustic diaphragm 63a.
In this way, by installing the front magnet plate 67 with the magnetization direction facing the rear magnet plate 61, the effective magnetic flux density in the acoustic diaphragm 63a is doubled compared to the case of only the rear magnet plate 61. Can be raised up to.

In the fourth embodiment, a front magnet plate 67 having a magnetization direction opposite to the rear magnet plate 61 is also installed in front of the acoustic diaphragm 63a. Such a structure is an electroacoustic transducer that reproduces a low frequency range. 60 is very convenient.
Since the amplitude of the acoustic diaphragm 63a increases during low-frequency reproduction, it is necessary to increase the distance between the rear magnet plate 61 and the front magnet plate 67 with respect to the acoustic diaphragm 63a so as not to hit the magnet plate. As this interval increases, the effective magnetic flux density formed on the acoustic diaphragm 63a decreases. As a method of increasing the effective magnetic flux density to be lowered, the position where the front magnet plate 67 is installed on the front side of the acoustic diaphragm 63a is closer to the acoustic diaphragm 63a than the rear magnet plate 61 is thickened on the rear side. This is efficient because the amount of magnets can be increased.
Furthermore, when only one rear magnet plate 61 is disposed with respect to the acoustic diaphragm 63a, the effective magnetic flux density decreases as the acoustic diaphragm 63a moves away from the rear magnet plate 61. Accordingly, the effective magnetic flux density at each position of the vibrating acoustic diaphragm 63a is asymmetric in the vibration direction with respect to the installation position of the acoustic diaphragm 63a. On the other hand, in the fourth embodiment, since the front magnet plate 67 having the magnetization direction facing the rear magnet plate 61 is also installed in front of the acoustic diaphragm 63a, at each position of the vibrating acoustic diaphragm 63a. The effective magnetic flux density is symmetric in the vibration direction with respect to the installation position of the acoustic diaphragm 63a. In this way, distortion caused by the difference in effective magnetic flux density in the vibration direction of the acoustic diaphragm 63a can be suppressed.

Next, the influence on the sound by arranging the front magnet plate 67 in front of the acoustic diaphragm 63a will be described. In general, when the front magnet plate 67 is disposed in front of the acoustic diaphragm 63a, the space between the acoustic diaphragm 63a and the front magnet plate 67 is such that sound emitted from the front of the acoustic diaphragm 63a has a specific frequency. It becomes a cause to resonate unevenly. As the volume of the space between the acoustic diaphragm 63a and the front magnet plate 67 increases, the resonance frequency decreases, and as the area of the opening in the sound passage hole 68b or the sound passage hole 68c decreases, the resonance is reduced. Tend to become stronger.
However, even in a general example in which the outer diameter of the acoustic diaphragm 63a is 15 cm and the distance between the acoustic diaphragm 63a and the front magnet plate 67 is 10 mm, the resonance frequency does not become lower than 1000 Hz. . When the structure of the fourth embodiment is adopted, the effect increases as the amplitude of the acoustic diaphragm 63a increases, but the frequency band in which the effect can be used is generally much lower than 1000 Hz. Accordingly, it is easy to avoid the frequency that causes the resonance, and it is unlikely to cause substantial problems.
Thus, in the electroacoustic transducer 60 that reproduces the low frequency range, there is no influence on the sound quality due to resonance or the like, and the method of installing the front magnet plate 67 on the front side of the acoustic diaphragm 63a can be used effectively.

According to the electroacoustic transducer 60 in the fourth embodiment of the present invention as described above, the following operation is obtained in addition to the operation described in the first embodiment.
(1) In reproduction in the low frequency range, it is necessary to increase the distance between the acoustic diaphragm 63a and the rear magnet plate 61 in order to prevent the acoustic diaphragm 63a having a large amplitude from hitting. The effective working magnetic flux density formed on 63a decreases. As a countermeasure, even if the rear magnet plate 61 is made thicker on the rear side, the magnet portion to be increased is separated from the acoustic diaphragm 63a, so it is difficult to efficiently increase the effective working magnetic flux density. In the electroacoustic transducer 60, by installing the front magnet plate 67 on the front side of the acoustic diaphragm 63a, the amount of magnets can be increased at a position close to the acoustic diaphragm 63a, so that the effective working magnetic flux density is efficiently increased. Can do.
(2) In addition to the rear magnet plate 61, a front magnet plate 67 having a magnetization direction facing the magnet plate 61 is installed in front of the acoustic vibration plate 63a, whereby the acoustic vibration plate 63a that vibrates in the front-rear direction is provided. The effective magnetic flux density at each position can be made symmetric in the vibration direction with respect to the installation position of the acoustic diaphragm 63a. Thereby, the distortion which arises by the difference of the height of an effective action magnetic flux density in the vibration direction of the acoustic diaphragm 63a can be suppressed.

As mentioned above, although Embodiment 1-4 was described, this invention is applicable, without being limited to these. For example, the electroacoustic transducer of the present invention is not limited to the specific size and material shown in each embodiment, and the entire NS pole of the displayed magnetic pole is reversed. It doesn't matter.
In addition, although the structure was described mainly taking the speaker which converts an electrical signal into a sound as an example, it can apply also to headphones, an earphone, etc. as something similar. It can also be applied to microphones, sound wave sensors, etc., as a means to convert received sound into electrical signals.

Hereinafter, the present invention will be specifically described by way of examples.
With respect to the three-directionally magnetized magnet plate formed with the same configuration as in the first embodiment, an analysis by simulation was performed to see how the distribution of the effective acting magnetic flux density changes depending on the magnetization angle of each partial region.
(Analysis example 1)
In an example using a magnet plate of three-direction magnetization, the magnetization angle and size of each partial region are the same as those of the magnet plate 11 in the electroacoustic transducer 10 of the first embodiment.
Each partial region of the magnet plate 11 in the electroacoustic transducer 10 of the first embodiment is divided into small parts, and the magnetization direction and strength data in the divided small regions are incorporated into the program. Then, the strength of the magnetic field contributing to the acoustic diaphragm 13a from each position of the magnet plate 11 is calculated using Bio-Savart's law, analyzed by the finite element method, and effective magnetic flux density in the acoustic diaphragm 13a is calculated. The distribution was determined.

(Comparative Example 1)
This is an example in which a magnet plate of radial magnetization is used and the magnetization angle is 0 degree.
As in the first embodiment, the magnetization angle θ of the basic area magnet 11b is set to 0 degree, but the magnetization angles of the central area magnet 11a and the outer peripheral area magnet 11c are also set to 0 degrees, which is the same as that of the basic area magnet 11b. That is, in the magnetization direction of all the partial regions, the distribution of the effective magnetic flux density in the acoustic diaphragm 13a when the magnetization angle θ is 0 degree and the radial direction of the acoustic diaphragm 13a is obtained in the same manner as in Analysis Example 1. .

(Comparative Example 2)
This is an example using a magnet plate with two-direction magnetization.
The distribution of the effective magnetic flux density in the acoustic diaphragm 13a was obtained under the same conditions as in Comparative Example 1 except that the magnetization angle θ on the center region magnet 11a side was set to +90 degrees as in the first embodiment.

(Comparative Example 3)
This is an example using a magnet plate with two-direction magnetization.
The distribution of effective magnetic flux density in the acoustic diaphragm 13a was obtained under the same conditions as in Comparative Example 1 except that the magnetization angle θ on the outer peripheral area magnet 11c side was set to −90 degrees, which was the same as that in the first embodiment.

(Analysis example 2)
In an example using a magnet plate of three-direction magnetization, the magnetization angle of each partial region is the angle that maximizes the use efficiency of magnetic flux.
About the magnet plate 11 in the electroacoustic transducer 10 of Embodiment 1, it calculated | required about the magnetization angle which can raise the utilization efficiency of magnetic flux most. This angle varies depending on the region of the conductor portion in the acoustic diaphragm 13a, the distance between the magnet plate 11 and the acoustic diaphragm 13a, and the width and thickness of each partial region in the magnet plate 11.
The magnetization angle of the partial region where the value obtained by integrating the effective working magnetic flux in the conductor of the acoustic diaphragm 13a in the region of the conductor is maximized in order to maximize the use efficiency of the magnetic flux in the three-direction magnetized magnet plate 11. Is the optimum magnetization angle. Such an angle was obtained by repeating trial and error while changing the magnetization angle θ for each type of partial region in the simulation.
The results were 23 degrees for the basic area magnet 11b, 88 degrees for the central area magnet 11a, and -90 degrees for the outer area area magnet 11c.

FIG. 6 is a diagram showing effective magnetic flux density in the radial direction of the acoustic diaphragm of the electroacoustic transducer.
In FIG. 6, the horizontal axis represents the distance from the center of the acoustic diaphragm 13a, and the vertical axis represents the effective magnetic flux density at each distance from the center of the acoustic diaphragm 13a. In the horizontal axis, the position of 12 mm is the inner peripheral edge of the conductor of the acoustic diaphragm 13a, and the position of 30 mm is the outer peripheral edge. Accordingly, a driving force acts on the conductor of the acoustic diaphragm 13a in proportion to the effective acting magnetic flux density between the 12mm position and the 30mm position in the figure.
In Comparative Example 2, compared with Comparative Example 1, the area on the inner peripheral side is reduced and narrowed in the region where the effective magnetic flux density is high by setting the magnetization angle θ of the center region magnet 11a to +90 degrees. The acting magnetic flux density is generally increased, and the inner peripheral side is particularly increased.
In Comparative Example 3, compared with Comparative Example 1, by setting the magnetization angle θ of the outer peripheral region magnet 11c to −90 degrees, the region on the outer peripheral side is reduced and narrowed in the region where the effective working magnetic flux density is high. The acting magnetic flux density is generally increased, and the outer peripheral side is particularly increased.

The distribution of effective acting magnetic flux density in Analysis Example 1 (Embodiment 1) has a characteristic in which the characteristic on the inner peripheral side of Comparative Example 2 and the characteristic on the outer peripheral side of Comparative Example 3 are combined. That is, in the region where the effective working magnetic flux density is high, the inner peripheral side and the outer peripheral side regions are both reduced and narrowed, but the effective working magnetic flux density is greatly increased as a whole.
And when the value which integrated the effective action magnetic flux in the area | region between the radius 12mm which is a conductor part of the acoustic diaphragm 13a and the radius 30mm is compared, the distribution of the magnet plate 11 of the analysis example 1 (Embodiment 1) is compared. In the case of the reference, the value was 58% in the comparative example 1 using the radial magnetization magnet plate in which the magnetization angle θ of all the partial regions was 0 degree. If a large diameter acoustic diaphragm 13a is used, this is not the case. However, it has been found that if a general diameter is used for the acoustic diaphragm 13a, such a low value is obtained.

As described above, when the magnetization angle θ is 0 degree in the magnetization direction of the basic region magnet 11b and the radial direction is toward the center of the acoustic diaphragm 13a, the central region magnet on the center side of the basic region magnet 11b. The effective magnetic flux can be concentrated by directing the magnetization angle θ of 11a toward +90 degrees, or by directing the magnetization angle θ of the outer peripheral area magnet 11c, which is the outer peripheral side of the basic area magnet 11b, toward −90 degrees. It has been found that a very high effective magnetic flux density distribution can be formed in a narrow range. Until now, the magnet plates with radial magnetization generally have a tendency that the effective magnetic flux is dispersed in a wide range and distributed in a wider range than the conductor region of the acoustic vibration plate 13a. In such a case, it has been found that a magnet plate having three-direction magnetization and a magnet plate having two-direction magnetization are very effective means for increasing the density by concentrating the effective magnetic flux in a necessary region.
Also, in the speaker, the diameter of the acoustic diaphragm 13a needs to be reduced in order to improve the directivity as the reproduction band becomes higher, but the efficiency is reduced if the area of the diaphragm is reduced. It is necessary to increase the magnetic flux density. In particular, it has been found that this is a very effective means.

In addition, in the magnet plate in which the magnetization angle from which the analysis example 2 is obtained is optimized, the value obtained by integrating the effective working magnetic flux in the conductor of the acoustic diaphragm 13a in the region of the conductor is obtained. It was 105% when the magnet plate 11 of the form 1) was adopted.
As described above, in each size employed in the first embodiment, the center region magnet 11a has the highest use efficiency of the magnetic flux when the magnetization angle θ is 88 degrees. When this angle is reduced, the use efficiency of the magnetic flux is lowered while the region having a high effective magnetic flux density is expanded until it reaches around 20 degrees. Further, the outer peripheral area magnet 11c has the highest magnetic flux utilization efficiency when the magnetization angle θ is set to −90 degrees. And when this angle is brought close to 0 degrees, the use efficiency of the magnetic flux decreases as the region having a high effective magnetic flux density spreads.
When such a feature relating to the distribution of effective magnetic flux density is used for a speaker, a method that can maximize the value obtained by integrating the effective magnetic flux in the conductor of the acoustic diaphragm 13a in the region of the conductor is selected in terms of efficiency. Will do. In a loudspeaker or a midspeaker, since the area of the conductor portion of the acoustic diaphragm 13a cannot be increased, it is a preferential condition that a very high effective magnetic flux density distribution can be formed in a narrow range. In the loudspeaker, it is also necessary to increase the area of the conductor portion of the acoustic diaphragm 13a so that the amplitude does not increase. Thus, in order to determine the magnetization angle θ of the center area magnet 11a and the outer area magnet 11c, it is necessary to consider not only the height of the effective magnetic flux density but also the width of the area having a high effective magnetic flux density. . In addition, it is necessary to decide in consideration of the ease of magnetization at the time of magnet manufacture, the uniformity of the distribution of effective magnetic flux density, the direction and strength of the magnetic force acting on the basic region magnet 11b, and the like.

  The present invention does not require any special shape or processing as a magnet, and it is not necessary to set the magnetization direction finely, and the manufacturing process is extremely simple like a radially magnetized magnet plate. Speakers, headphones, earphones, etc. that can efficiently convert low-distortion electrical signals into sound with a higher effective magnetic flux density distribution for acoustic diaphragm conductors than magnet plates. Therefore, it is possible to achieve the widespread use of electroacoustic transducers such as microphones and sound wave sensors that can efficiently perform conversion from electric signals to electric signals with low distortion.

Claims (7)

A disc-shaped or ring-shaped acoustic vibration plate comprising a magnet plate formed entirely in a disc shape or a ring shape, and a planar coil formed in parallel with the magnet plate and wound around a conductor. An electroacoustic transducer having:
In addition to the basic region magnet magnetized so that the component parallel to the vibration surface of the acoustic diaphragm in the magnetization direction of each partial region of the magnet plate is in the radial direction toward the center of the acoustic diaphragm, the basic region At the position on the outer side of the central area magnet or the basic area magnet magnetized so that the component parallel to the central axis of the acoustic diaphragm is in the forward direction of the acoustic diaphragm at the position on the center side of the magnet An electroacoustic transducer comprising at least one of outer peripheral area magnets magnetized so that a component parallel to a central axis of the acoustic diaphragm is in a rearward direction of the acoustic diaphragm. A disc-shaped or ring-shaped acoustic vibration plate comprising a magnet plate formed entirely in a disc shape or a ring shape, and a planar coil formed in parallel with the magnet plate and wound around a conductor. An electroacoustic transducer having:
In addition to the basic region magnet magnetized so that the component parallel to the vibration surface of the acoustic diaphragm in the magnetization direction of each partial region of the magnet plate is in the radial direction toward the outer periphery of the acoustic diaphragm, the basic region At a position on the outer side of the center area magnet or the basic area magnet magnetized so that a component parallel to the center axis of the acoustic diaphragm is in the rear direction of the acoustic diaphragm at a position on the center side of the magnet An electroacoustic transducer comprising at least one of outer peripheral area magnets magnetized so that a component parallel to a central axis of the acoustic diaphragm is in a forward direction of the acoustic diaphragm.   The magnet plate has a frame for fixing at least one of the central region magnet or the outer peripheral region magnet on a side opposite to the side where the acoustic diaphragm is installed, and the central region magnet or the outer peripheral region The electroacoustic transducer according to claim 1 or 2, wherein the basic area magnet is fixed to the frame by a magnetic force by which the magnet presses the basic area magnet toward the frame side.   A front center region magnet which is arranged in a position symmetrical to the center region magnet with the acoustic diaphragm interposed therebetween and is magnetized in a direction symmetrical to the magnetization direction of the center region magnet with respect to the vibration surface of the acoustic diaphragm; Alternatively, the front outer peripheral area magnet which is arranged at a position symmetrical to the outer peripheral area magnet with the acoustic diaphragm interposed therebetween and is magnetized in a direction symmetrical to the magnetization direction of the outer peripheral area magnet with respect to the vibration surface of the acoustic vibration plate The electroacoustic transducer according to claim 1, comprising at least one of the following.   A front basic area magnet that is arranged at a position symmetrical to the basic area magnet across the acoustic diaphragm and is magnetized in a direction symmetrical to the magnetization direction of the basic area magnet with respect to the vibration surface of the acoustic diaphragm. The electroacoustic transducer according to claim 4, wherein the electroacoustic transducer is provided.   2. The sound passage hole through which at least one of the basic region magnet, the outer peripheral region magnet, and the central region magnet of the magnet plate allows a sound generated outside or inside to pass therethrough. Or the electroacoustic transducer of 2.   An electroacoustic transducer according to claim 1 or 2, wherein a plurality of electroacoustic transducers are concentrically arranged with different sizes.

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