JPS5811158B2 - electromagnetic acoustic transducer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved electromagnetic acoustic transducer mainly for use in loudspeakers, in which the diaphragm does not have a flat part and deformation due to air pressure and inertia caused by vibration of the diaphragm and at the end of the vibration. The diaphragm can be vibrated in its original shape without restoring the deformed part, enabling faithful reproduction, improving acoustic characteristics, and holding the periphery of the diaphragm with a bellows-shaped elastic body. Furthermore, it operates with sufficient follow-up even at large amplitudes, can faithfully reproduce bass frequencies in particular, and can also increase permissible input.

The conventionally known bellows-shaped electromagnetic acoustic transducer is
Since the diaphragm is made up of a large number of elongated rectangular flat parts, when the diaphragm vibrates, the center of the flat part expands and deforms in the opposite direction to the vibration direction due to air resistance and inertia. At the end, the bulging deformed part is restored due to the decrease in air resistance and the elasticity of the diaphragm, so the diaphragm does not vibrate uniformly over the entire surface, but vibrates while partially deforming, resulting in faithful reproduction of sound. There was a drawback that it was not possible to obtain

The present invention eliminates the above-mentioned conventional drawbacks, and uses a rectangular plate-shaped diaphragm made of a thin film body formed by arranging a plurality of semicylindrical protrusions in parallel, thereby reducing the air resistance of the diaphragm. By preventing partial deformation due to inertia, vibrating the entire surface uniformly, and supporting the outer periphery of the diaphragm with an elastic body formed in a bellows shape in a plane perpendicular to the vibration direction of the diaphragm, The support part on the outer periphery of the diaphragm is made to vibrate freely only in the vibration direction of the diaphragm, thereby preventing anti-phase vibration (anti-resonance) and improving the frequency characteristics of the diaphragm.
It is an object of the present invention to provide an electromagnetic acoustic transducer that can flatten the entire frequency band.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a partially removed exploded view of the diaphragm applied to the present invention, showing polyester, polyethylene, polypropylene,
A film of synthetic resin such as nylon that is relatively unaffected by room temperature and has a thickness of about 10 to 100μ, or a film with a thickness of 50 to 15μ
On the surface of a rectangular thin film body 1 such as a diaphragm paper material with a thickness of about 0μ or a non-magnetic metal foil such as titanium or aluminum with a thickness of about 10 to 100μ with a thin insulating layer layered on the surface on which a conductor to be described later will be formed. , a portion 2 that becomes a semicylindrical protrusion 2 after molding
A continuous serpentine conducting wire 5 of about 5 to 20 ohm is formed in the parts 3' and 4' which become the top part 3 and valley part 4 of ', and
A conductive wire 6 similar to the conductive wire 5 is formed on the back side with a one-pitch phase difference, and the terminal 5b of the conductor 5a at the top portion 3' of the end of the conductor 5 and the trough 4 at the end of the conductor 6 on the back surface are formed. The terminal 6b of the conducting wire 6a of the portion 4' is electrically coupled with the terminal 6b of the conducting wire 6a by means of eyelets or other means I, and the conducting wire 5 and the conducting wire 6 are connected in series. Article 2
They are installed side by side.

Therefore, the sound current flows in the same direction in the conductors 5 and 6 of each valley 4 of the obtained diaphragm 8, and the sound current flows in the opposite direction in the conductors 5 and 6 of the top 3 of the semicylindrical protrusion 2. Although current flows, it is not affected by the magnetic flux caused by the magnet described later.

9 and 10 are lead wires. The conductive wires 5 and 6 are formed by known means such as printed wiring or vapor deposition.

Note that the conducting wire can also be formed on only one side and used as a diaphragm.

FIG. 2 is a partially removed exploded view of another diaphragm applied to the present invention, in which the surface of the thin film body 1 made of the above-mentioned material is
Meandering 5 to 2 continuous to the part 41 that will become the trough 4 after molding
A conductive wire 5 of approximately 0 ohm is formed, and a conductive wire 6 similar to the conductive wire 5 is formed on the back side with a one pitch change in phase to form the portion 4' that will become the valley portion 4, and the end of the conductive wire 5 is formed. Tanibe 4
After forming the conductive wire 5a at the portion 3' which becomes the top of the semicylindrical protrusion 2 at the end, the terminal 5b of the conductor 5a and the valley portion 4 at the end of the conductor 6 on the back side are formed. After connecting the terminal 6b of the conductor 6a of the portion 4' to be formed using an eyelet or other appropriate means 7, and connecting the conductor 5 and the conductor 6 in series, the semicylindrical protrusion 2 is formed by an appropriate forming means. are placed adjacent to each other.

For this reason, the conductors 5 and 6 in each valley 4 of the obtained diaphragm 8a
, the audio currents alternately flow in opposite directions, and the current flowing through the conducting wire 5a is not affected by the magnetic flux caused by the magnet, which will be described later.

9 and 10 are lead wires.

The conductive wires 5 and 6 are formed by known means such as printed wiring or vapor deposition.

The conducting wire can also be formed on only one side and used as a diaphragm.

FIG. 3 is a partially removed plan view of the electroacoustic transducer according to the present invention, and FIG. 4 is a partially removed enlarged sectional view taken along line iA in FIG. 3.

FIG. 5 is a cross-sectional view taken along line B--B in FIG. 4, with a portion removed.

On the inside of the frame pieces 22 facing each other on the upper surface of the frame 21, a bellows-shaped elastic body made of a paper material impregnated with a dangling agent or a sponge body made of synthetic resin or synthetic rubber is fixed by an appropriate means such as an adhesive. The bellows-shaped elastic bodies 23 and 24
Support parts 12 and 13 on both sides of the outer periphery of the diaphragm 8 are fixed to the lower surface of the diaphragm 8 by appropriate means such as adhesive, and a support frame 25 is fixed to the inner surface of the lower part of the frame body 21 by appropriate means such as adhesive or screws. The upper surface of .26 and the support part 12 of the diaphragm 8
．． The above-mentioned bellows-shaped elastic bodies 23 and 24 are inserted between the two parts 13 and 13, and fixed by appropriate means, such as adhesive.

The diaphragm 8 on the side perpendicular to the semicylindrical protrusion 2 of the diaphragm 8
On the back of both ends, a light metal such as aluminum or titanium, or an organic material such as paper or resin, which blocks the air passage leading to the front side of the diaphragm 8, is processed to be thin enough to not be deformed by the vibration of the diaphragm 8. The support plates 27 and 28 in the shape of a letter are fixed with a suitable adhesive and are suspended from the back side of the diaphragm 8.

A protruding plate 29 is provided so that the upper parts of the supporting plates 27 and 28 serve as supporting parts.
, 30 are on the same plane as the support part 12.13 of the diaphragm 8, and the protruding plate 29.30 is placed between the frame piece 22 and the support frame 25.26 in the same way as the support part 12.13. In the same manner as described above, it is held between bellows-shaped elastic bodies 23 and 24 of the same material.

In addition, the support plates 27 and 28, the protruding plates 29 and 30, and the diaphragm 8
are not limited to those in this embodiment, and may be formed integrally.

A bottom plate 15 having a large number of through holes or grooves 14 opening on the back surface of the diaphragm 8 is attached to the frame body 21, and the conducting wires 5 are attached to the frame body 21 so as not to block the through holes or grooves 14 of the bottom plate 15.
, 6, a magnet 16 is fixed between each trough 4 of the diaphragm 8, as described with reference to FIG.

When an audio current is applied through the lead wires 9 and 10, the audio current flowing through the conductors 5 and 6 of each valley portion 4 causes the diaphragm 8 to vibrate all over and reproduce the audio current according to Fleming's left hand rule.

The diaphragm 8 has a plurality of semicylindrical protrusions 2 arranged adjacently in parallel.
Therefore, partial deformation due to air pressure and inertia caused by vibration does not occur.

Therefore, highly faithful reproduced audio can be obtained.

Furthermore, since the periphery of the diaphragm 8 is supported by the bellows-shaped elastic bodies 23 and 24, even if the amplitude of the diaphragm 8 is large, it can sufficiently follow and operate, and faithfully reproduce the bass range. The allowable input power can also be increased.

In particular, by arranging the elastic bodies 23 and 24 formed in a bellows shape at a surface position perpendicular to the vibration direction on the outer peripheral support portion of the diaphragm 8, the diaphragm 8 can easily follow the vibration direction. Therefore, no distortion occurs in the vibration mode of the diaphragm 8.

Furthermore, by arranging the bellows-shaped elastic bodies 23 and 24 around the entire circumference of the diaphragm 8, it is possible to more reliably prevent the diaphragm 8 from being displaced in a direction perpendicular to the vibration direction. It is possible to flatten the frequency characteristics, and furthermore, since the elastic bodies 23 and 24 are all around the diaphragm 8, the diaphragm 8
It has a function to prevent sound from the back side from going around to the front side.

In addition, support plates 27 and 28 are fixed to both ends of the diaphragm 8 on the side perpendicular to the protrusions 2 so as to close these, so that when the diaphragm 8 vibrates, the diaphragm 8 It is possible to effectively prevent the opposite phase sound waves generated on the back side from going around to the front side of the diaphragm 8, and furthermore, the opposite phase sound waves can be effectively prevented from going around to the front side of the diaphragm 8. Furthermore, the sound waves with the opposite phase can be prevented from going around to the rear side from the many through holes or grooves 14 of the bottom plate 15. Since the sound is released, the deterioration of the low frequency characteristics can be effectively improved.

Note that depending on the size of the diaphragm 8, the predicted maximum amplitude, and other conditions, only either the upper surface or the lower surface of the support portion of the diaphragm 8 may be supported by a bellows-shaped elastic body.

6 and 7 show the relationship between the diaphragm 8a shown in FIG. 2 and the magnet.

Audio currents alternately flow in opposite directions through the conductive wires 5 and 6 in each valley 4 of the diaphragm 8a, and therefore the magnet 16 is made of permanent magnet pieces 16a and 16b made of a non-magnetic plate such as aluminum, copper, or synthetic resin. 16c, the same polarity is fixed facing each other, and the directions of magnetic flux generation are alternately opposite to each other.

In this case, the means for supporting the diaphragm 8a on the frame is as follows:
It is the same as the diaphragm 8 of the previous embodiment, and the effect is similar to that between valves.

The diaphragm applied to the present invention does not have a flat part and does not undergo deformation due to air pressure and inertia caused by vibration of the diaphragm and restoration of the deformed part at the end of vibration, so it is possible to obtain faithful reproduction of sound. In addition to significantly improving the acoustic characteristics, the periphery of the diaphragm is held by a bellows-like elastic body, so it operates with sufficient tracking even at large amplitudes, and faithfully reproduces bass frequencies in particular. It is possible to increase the allowable input.

As explained above, the electroacoustic transducer according to the present invention includes:
As the diaphragm uses a thin film body formed by arranging a plurality of semicylindrical protrusions in parallel, it is extremely lightweight and has a strong structure, so even when the diaphragm is displaced forward due to vibration. It has the remarkable feature that the protrusions do not change or distort, thereby suppressing as much as possible the generation of distorted sounds that become unnecessary abnormal sounds.

Furthermore, since the supporting part of the outer periphery of the diaphragm is fixed to the frame via an elastic body formed in a bellows shape at a surface position perpendicular to the vibration direction of the diaphragm, the supporting part of the outer periphery of the diaphragm is supported. The part can freely vibrate only in the vibration direction of the diaphragm, which can effectively prevent anti-phase vibration from occurring and flatten the frequency characteristics of the diaphragm over the entire frequency band. In addition, by fixing a hanging support plate to both ends of the diaphragm perpendicular to the protrusions, the opposite-phase sound waves generated on the back side of the diaphragm are transferred to the front side of the diaphragm. The support plate effectively prevents the diaphragm from going around to the diaphragm, resulting in excellent low-frequency characteristics.Furthermore, by providing a through hole in the bottom plate of the frame, it is possible to eliminate the opposite phase that occurs on the back side of the diaphragm. This has the excellent effect of actively releasing sound waves to the outside, and in particular, greatly improving low frequency characteristics.

[Brief explanation of drawings]

Fig. 1 is a developed view of a diaphragm showing the relationship between the diaphragm and conductor applied to the present invention, Fig. 2 is a developed view of a diaphragm showing another embodiment of the same as above, and Fig. 3 is an electromagnetic plate according to the present invention. A plan view of the acoustic transducer, FIG. 4 is a partially removed enlarged sectional view taken along the line A-A in FIG. 3, and FIG. 5 is a partially removed sectional view taken along the line B-B in FIG. 4. FIGS. 6 and 7 are partial cross-sectional views of two other embodiments. DESCRIPTION OF SYMBOLS 1...Thin film body, 2...Semi-cylindrical projection, 4...Trough, 5, 6...Conducting wire, 8
, 8a... diaphragm, 21... frame, 1
2, 13... Support part, 16...--□ Magnet, 23, 24... Bellows-shaped elastic body, 27° 28
・・・・・・−Support plate.

Claims (1)

[Claims] 1 A conductor is attached in series to each valley of a diaphragm made of a thin film body formed by arranging a plurality of semicylindrical protrusions in parallel, and a magnet that generates magnetic flux orthogonal to the conductor in each valley is attached to each valley. The supporting portion of the outer periphery of the diaphragm is fixed to the frame via an elastic body formed in a bellows shape at a surface position orthogonal to the vibration direction of the diaphragm, and the vibration On the back side of both ends of the diaphragm on the side perpendicular to the protrusions of the plate, a support plate is fixed that hangs down and blocks the air passage leading to the front side of the diaphragm through both ends of the diaphragm. An electromagnetic acoustic transducer characterized by having a through hole in the bottom plate.