JPH02180499A - Induction type speaker - Google Patents

Abstract

PURPOSE:To maintain an interval between respective coils with high accuracy by providing a plane in one of a voice coil and feeding coil at least and composing an induction type speaker of a conducting member which is closely wound. CONSTITUTION:A voice coil 10 is formed by circularly winding an angular wire member 100 such as copper wire as the conductive member of a rectangular cross section, for which a mutually overlapped contact surface is caused to be a plane 100a when the coil is wound circularly at least, around the outer circumferential surface of a voice coil bobbin 11. Samely, a feeding coil 13 is also formed by edge-wise winding to closely spirally winding the angular wire member 100, which is formed samely as the voice coil 10, so that the plane 100a can mutually contact. This feeding coil 13 is cylindrically formed with height H1 coincident with thickness W1 of a top plate 6 so that an outer circumferential diameter can be almost coincident with the inner circumferential diameter of the top plate 6.

Description

[Detailed Description of the Invention] A. Industrial Field of Application The present invention provides a method in which a feeding coil is disposed on the magnetic circuit side opposite to a voice coil supported by a swing plate, and an acoustic signal current is supplied to the feeding coil. The present invention relates to an induction type speaker in which the diaphragm is driven by inducing an induced current in the voice coil by magnetic induction.

B1 Summary of the Invention The present invention provides at least one of a short-circuited voice coil supported by a diaphragm and a feeding coil arranged in a magnetic circuit opposite to this voice coil, which has a flat surface and is closely wound. By constructing the coil with a conductive member, the coil volume per predetermined volume is increased and the heat dissipation effect is enhanced.

The above-mentioned voice The circuit is used to efficiently transmit acoustic signals between the coil and the feeding coil.

C1 Prior Art Conventionally, electrodynamic speakers have been widely used as speakers. This electrodynamic speaker is wound around a voice coil bobbin supported by a diaphragm, and supplies an acoustic signal current to the voice coil placed in a DC magnetic field. Then, a driving force corresponding to the acoustic signal current supplied to the voice coil is obtained, and the driving horn causes the diaphragm to vibrate, thereby reproducing sound corresponding to the ¥r9 signal.

The acoustic signal current is supplied to the voice coil through a lead wire fixed to a part of the diaphragm. By disposing wires such as lead wires on the diaphragm that is driven by vibration in this way, there is a risk that the degree of freedom of the diaphragm may be impaired and the linearity of the reciprocating motion of the diaphragm during vibration may be inhibited. . Therefore, the lead wire is made of a wire material such as an extremely thin tinsel wire in order to maintain linearity during vibration without causing a large load when the diaphragm vibrates, and without impairing the degree of freedom. Since such an extremely thin wire does not have sufficient mechanical strength, there is a problem that the wire may break due to vibration of the diaphragm. Moreover, even if the lead wire is not cut, the lead wire itself resonates, causing abnormal noise and distorting the reproduced sound, resulting in deterioration of the sound reproduction characteristics.

In order to solve the problems of electrodynamic speakers as described above, an induced current is induced in the voice coil supported by the diaphragm by magnetic induction without using a lead wire arranged on the diaphragm side. An induction type speaker that drives the above-mentioned diaphragm has been proposed.

As this kind of induction type speaker,
9 and Utility Model Application Publication No. 50-105438 are known.

The induction type speaker disclosed in each of the above-mentioned publications has a feeding coil disposed on the magnetic circuit side facing a voice coil supported by a diaphragm, and an acoustic signal current is supplied to this feeding coil to generate the above-mentioned information by magnetic induction. The voice coil is configured to induce an induced current corresponding to the acoustic signal current in the voice coil. That is, in the induction type speaker, when an AC signal from an audio frequency power amplifier is supplied to the power supply coil, the AC signal causes the power supply coil to generate an AC magnetic flux corresponding to an input waveform. This alternating current magnetic flux closely interlinks with the voice coil, which is disposed close to and facing the feeding coil. On the other hand, since the voice coil itself is short-circuited, a short-circuit current flows due to the above-mentioned alternating current magnetic flux. The voice coil is located within a magnetic field formed by a pole piece and surrounding magnetic poles that constitute a magnetic circuit. Therefore, a driving force proportional to the product of the magnetic field strength and the short-circuit current acts on the voice coil. This driving force passes from the voice coil through the voice coil bobbin to vibrate a diaphragm integrated with the voice coil bobbin.

As a result, reproduced sound is radiated from the diaphragm similarly to an electrodynamic speaker.

As mentioned above, the induction type speakers disclosed in the above-mentioned publications do not require the use of wires such as lead wires fixed to the diaphragm side like electrodynamic speakers. It is possible to solve the problems that arise.

D9 Problems to be Solved by the Invention By the way, the induction type speaker as described above induces an induced current in the voice coil disposed on the diaphragm side, which corresponds to the acoustic signal current supplied to the feeding coil by magnetic induction. Since the above-mentioned diaphragm is vibrated and driven by
In order to vibrate the diaphragm with good response to acoustic signals and with high efficiency, it is necessary to improve the transmission characteristics and induce an induced current from the feeding coil to the voice coil with high efficiency. In order to improve the transmission characteristics on the voice coil side and induce an induced current, it is necessary to increase the electromagnetic coupling between the power feeding coil and the voice coil. Therefore, it is required to further narrow the magnetic gap of the magnetic circuit, increase the magnetic flux density of the magnetic gap, and bring the power supply coil and voice coil closer together.

Furthermore, in order to improve the transfer characteristics and induce the acoustic signal current supplied to the feeding coil to be transmitted to the voice coil side with high efficiency, it is necessary to increase the number of windings on the voice coil side, that is, to improve the winding density. This is required. Alternatively, it is required to increase the coil diameter used in the voice coil to increase the occupancy rate of the coil within a predetermined winding space nn.

Furthermore, in order to increase the vibration driving force of the diaphragm and obtain good sound pressure frequency characteristics, it is necessary to increase the amount of acoustic signal current that can be supplied to the power feeding coil side. In order to increase the amount of acoustic signal current that can be supplied, the diameters of the coils used in the feeding coil to which the acoustic signal current is supplied and the voice coil in which the acoustic signal current is induced are increased to reduce the electrical resistance of each coil. This is required.

However, the power supply coil and voice coil in conventional induction speakers are formed by winding round wires with a circular cross section, so when they are wound, spaces are created between each wire, making it necessary to wind them closely together. I can't speak up. Therefore, there is a limit to increasing the number of turns of '4fA+t in a predetermined winding volume. Furthermore, there is a limit to the improvement in the occupation rate of the wire in a predetermined winding volume. Since there is a limit to the number of windings of the wire or the occupation rate of the wire in a given volume, it is necessary to improve the transfer characteristics so that the acoustic signal current supplied to the feeding coil can be transmitted and induced to the voice coil with high efficiency. I can't.

In addition, for coils constructed using round wire, there are limits to the number of turns in a given volume and the area occupied by the wire, so if you try to increase the number of turns or the volume occupied by the wire, the volume of each coil will increase. growing. As a result, in speakers using the above-mentioned coil, the magnetic gap of the magnetic circuit can be narrowed! : There is a limit to the distance between the feeding coil and the voice coil, and the distance between the feeding coil and the voice coil cannot be reduced, and the electromagnetic coupling between the feeding coil and the voice coil cannot be increased.

Furthermore, since a coil formed by winding a round wire has spaces between each wire as described above, it is difficult to increase the contact area with the magnetic circuit or voice coil bobbin that supports the coil. Therefore, the heat generated in the power supply coil and voice coil when driven by supplying an acoustic signal current cannot be efficiently transmitted to the magnetic circuit that functions as a heat radiator, the damper that supports the diaphragm, etc. If heat is accumulated in the coil without efficient heat dissipation, the effect of this heat will cause wire breakage.Therefore, in coils using round wire, measures are taken to prevent wire breakage due to heat generation. To prevent this, there is a limit to reducing the thickness of the wire used, and it is not possible to increase the number of turns of the coil per predetermined volume. Transmission cannot be performed, and an induction type speaker that can achieve efficient vibration drive of the diaphragm cannot be constructed.

Therefore, the present invention was proposed with the aim of solving the problems that conventional induction type speakers have.

The present invention further narrows the magnetic gap of the magnetic circuit, increases the magnetic flux density of the magnetic gap, and arranges the feeding coil and the voice coil close to each other to improve the transmission characteristics and improve the transmission of acoustic signals to the voice coil. The present invention aims to provide an induction type speaker 1 that enables efficient vibration driving of a diaphragm.

Further, it is an object of the present invention to provide a highly efficient induction speaker that makes it possible to efficiently dissipate heat generated by a power supply coil or a voice coil, increase the amount of acoustic signal current that can be supplied, and provide a highly efficient induction speaker.

89 Means for Solving the Problems In order to achieve the above-mentioned objects, the present invention includes a magnetic circuit, a diaphragm movably supported with respect to the magnetic circuit, and a diaphragm supported by the diaphragm and the magnetic circuit. a voice coil facing into a magnetic gap and short-circuited; and a feeding coil disposed in a magnetic circuit opposite to the voice coil, at least one of the voice coil and the feeding coil facing a flat surface. It is made of a conductive member which is closely wound.

F1 action In the present invention, at least one of the voice coil and the power feeding coil is made of a conductive member having a flat surface and tightly wound. It is possible to maintain the interval with high precision. As a result, the magnetic gap of the magnetic circuit in which each of the coils is located can be maintained with high accuracy in accordance with the precision of each coil, so that the interval between the magnetic gaps can be further reduced.

In addition, each of the above coils can increase the number of turns of the wire per predetermined volume, or increase the cross-sectional area of the wire when the number of turns of the wire per predetermined volume is constant. .

Furthermore, the contact area of the voice coil and feeding coil, which are formed of conductive members having a flat surface and closely wound, with respect to the magnetic circuit or the voice coil bobbin is increased, and efficient heat dissipation is achieved.

G. Examples Specific examples of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the induction type speaker according to the present invention has the following features:
It includes a magnetic circuit 1 and a diaphragm 2 movably supported with respect to the magnetic circuit 1.

The magnetic circuit I includes a yoke plate 4 having a pole piece 3 in the center and formed of a magnetic material, a ring-shaped magnet 5 placed on the yoke plate 4, and a ring-shaped magnet 5 placed on the magnet 5. It is composed of ring-shaped punch brakes 1 and 6 made of a magnetic material.

The inner peripheral surface of this top plate 6 and the top plate 6
The magnetic circuit l
A magnetic gap 7 is configured.

On the other hand, the diaphragm 2 is movably supported with respect to the magnetic circuit 1 via a frame 8 attached to the magnetic circuit 1 with its base end connected thereto. That is, the diaphragm 2 is supported by the frame 8 with its horn-shaped outer periphery being adhesively bonded to the periphery of the frame 8 together with the gasket 9.

A voice coil bobbin 11 around which a voice coil IO is wound is coupled to the center of this vibration Fi,2. This voice coil bobbin 11 is supported at its intermediate portion by a damper 12 whose outer peripheral edge side is fixed to a part of the 611 air circuit 1 or the frame 8, and is installed so as to fit into the magnetic gear knob 7 of the magnetic circuit 1 without eccentricity. It is being

The diaphragm 2, which is mounted with the outer peripheral edge side supported by the frame 8 and the voice coil bobbin 11 connected to the center part supported by the damper 2, is movable in the axial direction of the magnetic circuit 1. .

A center cap 2a is attached to the center of the diaphragm 2 so as to close the opening of the voice coil bobbin 11.

In addition, at a position facing into the magnetic gap 7 of the magnetic circuit l,
A feeding coil 13 is provided. This feeding coil 13
The inner periphery of the top plate 6 is connected such that it faces the voice coil 10 on the diaphragm 2 side, which is disposed in the magnetic gap 7, with a predetermined gap therebetween, without contacting the voice coil 10. installed.

As shown in FIG. 2, the voice coil 10 is made of a conductive member such as a copper wire, which has a rectangular cross section, with contact surfaces overlapping each other being flat surfaces 100a when wound at least in an annular shape. It is formed by winding a rectangular wire 100 in an annular shape around the outer peripheral surface of the voice coil bobbin 11.

That is, the voice coil 10 is made by winding a rectangular wire +00 shaped into a rectangular cross-section as shown in FIG. 2 in a spiral shape with the flat surfaces 100a in close contact with each other as shown in FIG. The voice coil bobbin 11 is wound edgewise in order in the height direction of the outer circumferential surface of the voice coil bobbin 11. This voice coil 10 has the above-mentioned rectangular wire rod 1
000 is wound with both ends short-circuited.

The voice coil 10 formed by edgewise winding the rectangular wire rods 100 as described above is formed by winding the rectangular wire rods 100 closely together without creating any space between the adjacent rectangular wire rods 100, as shown in FIG. , its outer circumferential surface 10a and inner circumferential surface 10b which contacts the voice coil bobbin II are uniform flat surfaces.

Note that the voice coil 10 formed by edgewise winding the rectangular wire lOO can sufficiently maintain its cylindrical shape even if it is not wound around a voice coil bobbin as a winding base. Therefore, this voice coil IO can be directly attached to the diaphragm 2 as shown in FIG. 5 without using a voice coil bobbin as shown in FIGS. 1 and 4.

By omitting the voice coil bobbin in this way,
The weight of the diaphragm 2 can be reduced.

Similarly to the voice coil 10, the feeding coil 3 is edgewise wound by winding a square wire rod 100 formed into a shape as shown in FIG. 2 in a spiral shape with the flat surfaces 100a in close contact with each other. It is formed by As shown in FIG. 4, this power supply coil 13 is formed into a circular vJ cane with a height H that matches the thickness Wl of the top plate 6 so that the outer diameter approximately corresponds to the inner diameter of the top plate 6. It will be done. This feeding coil 13 is provided with acoustic signal input terminals a and a', and an acoustic current signal is supplied through the input terminals aa' and a predetermined amplifier.

The power feeding coil 13 is attached with its outer periphery @ I E a side bonded to the inner peripheral surface of the top plate 6 . This feeding coil 13 also has an outer circumferential surface L3 that contacts the inner circumferential surface of the top plate 6, similarly to the voice coil IO.
a and its inner circumferential surface 13b are uniform flat surfaces.

The induction type speaker according to the present invention configured as described above has an input terminal a connected to the power feeding coil 13.

When an AC signal as an acoustic signal is supplied through a, an AC/A magnetic flux is generated corresponding to the human power waveform.

Based on the interlinkage magnetic flux caused by this alternating current magnetic flux, an induced current having the same frequency as the above alternating current is induced in the annular voice coil 10 by mutual induction. Since this voice coil 10 is located within the magnetic gap 7 of the magnetic circuit I,
A driving force proportional to the product of the strength of the DC magnetic field in the 6 m gap 7 and the induced current acts on the voice coil bobbin 11 around which the voice coil 10 is wound. That is, the induced current of the voice coil 10 acts on the DC magnetic field within the magnetic gap 7 to directly drive the diaphragm 2 to vibrate, thereby emitting sound waves.

In the above embodiment, the feeding coil 13 is attached to the top plate 6 side of the magnetic circuit 1, but as shown in FIG. You can also do this.

By the way, in the present invention, the voice coil 10 and the feeding coil 13 are formed by edgewise winding, in which the rectangular wire 100 is wound in close contact with each other so that the flat surfaces 100a are in contact with each other. The outer circumferential surface 10a of the voice coil 10 and the inner circumferential surface 13b of the power feeding coil 13, which face each other within the power supply coil 7, can be made uniform and flat surfaces. Therefore, the interval between the voice coil 10 and the feeding coil 13 can be controlled with high precision. Therefore, the interval between the magnetic gaps 7 of the magnetic circuit 1 can be narrowed, and acoustic signals can be efficiently transmitted.

Further, since the voice coil IO is wound around the coil bobbin 11 with the inner circumferential surface 10b, which is a uniform flat surface, in contact with the voice coil bobbin 11, the contact area with the voice coil bobbin 11 can be increased. Furthermore, the outer circumferential surface 1 of the feeding coil 13 is also a flat surface.
3a is attached in contact with the top plate 6, so that the contact area with the top plate 6 can be increased. Therefore, it is possible to increase the thermal conductivity to the components of the damper 12, top plate 6, etc. (■ circuit 1) that function as heat radiators, and to efficiently radiate heat generated in the voice coil 10 and power supply coil 13 during driving. Therefore, each coil lo due to heat generation
and 13, and increases the current that can be supplied to the feeding coil 13, making it possible to reproduce large-capacity sound.

Furthermore, the voice coil 10 and the feeding coil 13 are
Since the rectangular wire rods 100 are closely wound and formed, the number of windings of the wire rods 100 or the occupation rate of the wire rods 100 in a predetermined volume can be increased.
The acoustic signal current that can be supplied to the voice coil 10 can be induced to be transmitted to the voice coil 10 side with good transmission characteristics and with high efficiency,
The diaphragm 2 can be driven efficiently.

A comparison of the acoustic characteristics of the conventional induction type speaker using round wires and the speaker according to the present invention is as follows.

At this time, it is assumed that the acoustic signal currents supplied to the feeding coils are the same.

First, the sound pressure frequency characteristics of conventional induction speakers are
In contrast to the characteristic shown by A in the figure, the sound pressure frequency characteristic of the speaker according to the present invention shows the characteristic shown by B in FIG. As is clear from FIG. 7, according to the present invention, the sound pressure level can be improved over almost the entire reproducible frequency band, and the diaphragm 2 can be highly efficiently adjusted to the supplied acoustic signal current. can be driven.

Furthermore, while the frequency-impedance characteristic of a conventional induction type speaker exhibits a characteristic as shown by C in FIG. 8, the frequency-impedance characteristic of the speaker according to the present invention is as follows.
The characteristics shown in the middle of FIG. 8 are shown. The harmonic distortion characteristics of the conventional induction type speaker exhibit characteristics as shown by E in FIG. 8, whereas the harmonic distortion characteristics of the speaker according to the present invention are shown by F in FIG. It shows such characteristics.

As is clear from the characteristic diagram shown in FIG. 8, according to the speaker according to the present invention, the frequency-impedance characteristic can be improved and harmonic distortion can be improved.

In the above embodiment, the voice coil IO and the feeding coil 1
Although the voice coil 10 is formed of the rectangular wire rod 100, only the voice coil 10 may be formed of the rectangular wire rod 100 as shown in FIG. Furthermore, the 10th
As shown in the figure, only the power feeding side coil 13 is connected to the above square wire]
00 may be used.

As shown in FIGS. 9 and 10, if either the voice coil 10 or the feeding coil 13 is edgewise wound by winding a rectangular wire 100 closely so that the flat surfaces 100a are in contact with each other. , voice coil 1
0 and the feeding coil 13 can be controlled with high precision, and the interval between the magnetic gearings 7 of the magnetic circuit 1 can be narrowed. Furthermore, the heat dissipation effect of the coil 10 or 13 on the side using the square wire 100 can be improved, and the adverse effects of heat generation can be eliminated. Therefore, the coil 10 on the side that is more susceptible to heat generation
Or it is desirable to form 13 with a square wire rod 100,
Then, at least an improvement in sound pressure frequency characteristics can be achieved.

In the above-described embodiment, the voice coil 10 and/or the feeding coil 13 are formed of the rectangular wire rod 100, but as shown in FIG. Alternatively, they may be wound into a cylindrical shape so as to be laminated in concentric circles as shown in FIG. 12 with an insulating thin body 201 such as a thin synthetic resin body sandwiched therebetween. As shown in FIG. 11, a pair of lead-out portions 201a201b are formed at both ends of the conductive thin body 2010 to serve as connection portions for connecting to a lead wire or the like or for short-circuiting both ends. The lead-out portions 201a and 201b may be provided at both ends of the example side, taking into consideration the state of connection to lead wires and the like.

The voice coil 10 and the power supply coil I3 formed by winding the conductive thin body 200 as described above are in a state where the conductive thin body 200 is tightly wound and the conductivity in a predetermined volume is increased. The number of turns of the thin body 200 or the occupation rate of the conductive thin body 200 can be increased. Further, the voice coil 10 and the power feeding coil 13 have respective inner and outer circumferential surfaces 10.
a, 10b and 13a, 13b with the conductive thin body 200
The plane faces the surface, resulting in a uniform flat surface. Therefore,
The interval between the voice coil 10 and the feeding coil 13 can be controlled with high precision, and by narrowing the interval between the magnetic gaps 7 of the magnetic circuit 1, efficient acoustic signal transmission can be performed.

In particular, the voice coil 10 formed by winding the conductive thin body 200 can sufficiently maintain its cylindrical state in the wound state. Therefore, the voice coil 10 can be attached to the diaphragm 2 alone without using a voice coil bobbin, as shown in FIG. 13. Since the feeding coil 13 can be mounted with its uniformly flat outer circumferential surface 13a in contact with the inner circumferential surface of the tongue plate 6 of the magnetic circuit, heat generated during driving can be efficiently dissipated from the top plate 6, etc. Heat can be dissipated through.

In addition, in the case shown in FIG. 13, a part of the voice coil 10 that is displaced during driving and no longer faces the feeding coil 13 functions as a short ring, and the impedance characteristics are improved. Harmonic distortion can be improved.

H0 Effects of the Invention In the present invention, as described above, at least one of the voice coil and the feeding coil is composed of a conductive member having a flat surface and tightly wound, so that the winding accuracy can be improved. Therefore, the spacing between the coils can be maintained with high precision. As a result, the magnetic gap of the magnetic circuit in which each of the above coils is located can be maintained with high precision in accordance with the precision of each of the above coils, so the distance between the above magnetic gaps can be further reduced, and the efficiency between the voice coil and the feeding coil can be improved. It is possible to transmit a sound signal with good quality and reproduce sound with high efficiency.

In addition, each of the above coils can increase the number of turns of the wire or conductive thin body per predetermined volume, or when the number of turns of the wire or conductive thin body wound within a predetermined volume is constant. Since the cross-sectional area of the wire or conductive thin body can be increased, signal transmission characteristics can be improved, and the acoustic signal current supplied to the feeding coil can be increased, making it possible to obtain a large driving force. It can be done.

Furthermore, since the cross-sectional shape of the wire or conductive thin body can be freely selected, any wire rod or conductive thin body can be used, taking into account the width of the magnetic gap of the magnetic circuit, etc., and the number of turns in a given volume can be adjusted. First of all, it allows for a greater degree of freedom in design, such as being able to select freely.

Furthermore, since the voice coil and/or the power supply coil have a flat surface and are made of a closely wound conductive member, the contact area with the voice coil bobbin or magnetic circuit is increased, and efficient heat dissipation is achieved. This has been achieved, preventing damage to one member of each coil due to heat generation, and in particular increasing the current that can be supplied to the power feeding coil, making it possible to reproduce large-capacity sound.

Therefore, we aim to improve the sound pressure frequency characteristics and reproduce sound with extremely good sound quality without distortion.

It is possible to provide an inductive speaker that

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing one embodiment of a speaker according to the present invention, FIG. The figure is a partially cutaway perspective view showing the voice coil portion, and FIG. 4 is an enlarged sectional view showing the voice coil and feeding coil portion. FIG. 5 is a sectional view showing another example of how the voice coil is mounted. FIG. 6 is a sectional view showing an example in which the feeding coil is attached to the top plate side of the magnetic circuit. FIG. 7 is a characteristic diagram showing sound pressure-frequency characteristics in comparison with the conventional one, and FIG. 8 is a characteristic diagram showing impedance characteristics and distortion characteristics in comparison with the conventional one. FIG. 9 is a partially enlarged sectional view showing another example of the induction type speaker according to the present invention, and FIG. 1O is a partially enlarged sectional view showing still another example. FIG. 11 is a perspective view showing another example of the conductive member constituting the voice coil and the feeding coil, and FIG.
FIG. 3 is a perspective view showing a state in which the conductive member shown in the figure is wound;
FIG. 13 is a sectional view showing a conductive type speaker using a coil formed from the conductive member shown in FIG. 11. 1...Magnetic circuit 2...Diaphragm 7...Magnetic gap io...Voice coil 13...Feeding coil ioo...Square wire 200...Conductive thin body

Claims (1)

[Scope of Claims] A magnetic circuit, a diaphragm movably supported with respect to the magnetic circuit, a voice coil supported by the diaphragm, facing into the magnetic gap of the magnetic circuit, and short-circuited; and a power feeding coil disposed in the magnetic circuit opposite to the voice coil, at least one of the voice coil and the power feeding coil,
An induction type speaker comprising a conductive member having a flat surface and closely wound.