JPH0622393A - Coaxial speaker - Google Patents

Abstract

PURPOSE:To drive a device by constant currents by a simple constitution which can be easily manufactured. CONSTITUTION:Second diaphragms 30 and 32 including the second dome-shaped and corn-shaped diaphragm 32 held through a prescribed connecting means 28 by first diaphragm systems 20, 22, and 26 are allowed to follow the first diaphragm systems 20, 22, and 26, and the first corn-shaped diaphragm 20 is electromagnetically controlled, so that this device can be driven by the constant currents. Thus, the same-axial speaker which can be driven by the constant currents can be realized by the simple constitution which can be easily manufactured.

Description

Detailed Description of the Invention

[0001]

[Table of Contents] The present invention will be described in the following order. Industrial Application Conventional Technology (FIG. 4) Problem to be Solved by the Invention (FIG. 4) Means for Solving the Problem (FIGS. 1 and 3) Action (FIGS. 1 and 3) Example (FIG. 1) ~ Fig. 3) Effect of the invention

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coaxial speaker, and more particularly to a coaxial speaker which supplies a drive current to a secondary coil by electromagnetic coupling.

[0003]

2. Description of the Related Art Conventionally, in a coaxial speaker, a plurality of speakers are arranged on the same axis so that the positions of the sound sources of the speakers responsible for the high frequency range and the low frequency range are matched and the phase characteristics and the like are excellent. Some have been designed to get the sound source.

Since a plurality of independent speakers are used in this coaxial speaker, a plurality of magnetic circuits corresponding to the respective speakers are required, and it is difficult to attach a diaphragm so as to match the sound source positions of the plurality of speakers, and the manufacturing process is difficult. There was a complication.

Further, there is a possibility that one magnetic circuit of the plurality of magnetic circuits may inadvertently change the loci of the magnetic force lines of the other magnetic circuit, and further, the voice coil of the plurality of speakers has a cotton thread wire resistant to vibration. Since the speakers are electrically connected to each other, wiring between the speakers is complicated, and it is not easy to install a network for driving the speakers.

In order to solve these problems, JP-A-2-31
As disclosed in Japanese Patent Publication No. 598 and Japanese Patent Laid-Open No. 2-31599, voice coils for low and high frequencies are arranged in the same magnetic gear, and power is applied to the voice coil for high frequencies by electromagnetic coupling. There are those that are designed to supply and drive.

That is, in the coaxial speaker 1 shown in FIG. 4, a ring-shaped magnet 4 is fitted on the outer surface of a disk-shaped yoke 2 which is made of a magnetic material and constitutes a back plate. A plate 6 made of a magnetic material is fixed to the end surface.

A columnar pole 8 is integrally formed at the center of the yoke 2 in the plane, and a suspension 10 which is extendable and contractable upward is disposed on the upper side surface of the pole 8.
Further, the suspension 10 supports a bowl-shaped tweeter diaphragm 12 made of a conductive material at the upper end surface thereof, so that the degree of freedom of the tweeter diaphragm 12 against vibration is not reduced.

In addition, the tweeter diaphragm 12 forms a short-circuit coil 14 whose winding start and winding end are short-circuited as a whole, so that the driving current for low and middle frequencies generated in the short-circuit coil 14 is practically sufficiently attenuated. It is designed to do.

A frame 16 having a radial opening is fixed to the upper end surface of the plate 6, and one end of a damper 18 is fixed to the inner side surface of the frame 16. Further, the woofer diaphragm 20 is passed through the edge 20A on the upper end 16A of the frame 16.
The peripheral portion of is fixed.

A coil bobbin 22 is fixed to the center of the woofer diaphragm 20 so as to cover the tweeter diaphragm 12 with a predetermined diameter, and the other end of the damper 18 is fixed to the outer surface of the coil bobbin 22. . A primary coil 24 is wound around the peripheral side surface of the coil bobbin 22, and the coil 24 and the plate 6 are arranged so as to face each other.

When a drive current is supplied to the coil 24, the coil 24 receives a force in the direction of arrow a and the opposite direction according to Fleming's left hand rule, and a drive current is generated in the short-circuit coil 14 by transformer coupling. .

Therefore, in the speaker 1, the short-circuit coils 14 and 1 according to the drive current based on the input audio signal.
The next coil 24 vibrates in the direction indicated by the arrow a or in the direction opposite to the arrow a, whereby the tweeter diaphragm 12 and the woofer diaphragm 20 respectively vibrate to generate sound waves in a predetermined frequency band. ing.

Here, the short-circuit coil 1 adapted to cross the magnetic field formed between the plate 6 and the pole 8
4 and the coil 24, when a drive current based on an audio signal is supplied to the coil 24, the woofer diaphragm 20 vibrates to generate a sound wave from a predetermined low sound range to a middle sound range.

Further, at this time, due to the transformer coupling of the short-circuit coil 14 and the coil 24, a driving current flows in the short-circuit coil 14, which causes the tweeter diaphragm 12 to vibrate like the woofer diaphragm 20 and vibrate above a predetermined midrange. Sound waves up to the sound range are generated, and the coaxial speaker 1 is obtained in this manner.

[0016]

However, in the coaxial speaker 1 having such a configuration, since the tweeter diaphragm 12 is supported by the suspension 10, there is a problem that an additional manufacturing process is required for manufacturing the tweeter vibration system. is there. Further, since the tweeter diaphragm 12 is made of a conductive material, there is a possibility that the sound quality is limited due to high sensitivity.

Further, when an attempt is made to drive a constant current in such a coaxial speaker 1 in order to improve the sound quality, at the lowest resonance frequency (f0) and the frequency band around it,
There is a problem that the impedance of the coaxial speaker 1 increases and the sound pressure level rises, resulting in excessive vibration of the woofer diaphragm 20.

As a method of preventing the influence of the minimum resonance frequency (f0) and stably driving the speaker with a constant current, a braking coil is provided integrally with the speaker vibration system, and this is used as a magnetic circuit of the speaker vibration system. It has been proposed to dispose it in the air gap of a braking magnetic circuit independent of the above and to electromagnetically brake the vibration system of the speaker by this. However, even in this case, the structure is complicated and large due to the provision of the braking coil and the braking magnetic circuit, and the manufacturing process becomes complicated, which is still insufficient in practical use.

The present invention has been made in consideration of the above points, and an object thereof is to propose a coaxial speaker which can be driven at a constant current with a simple structure which is easy to manufacture.

[0020]

In order to solve such a problem, in the present invention, a cone-shaped first diaphragm 20 and predetermined magnetic fluxes 6 and 8 formed at the ends of the first diaphragm 20 are provided. A first oscillating system 20, 22, 26, which is a first voice coil 26 disposed inside, and is held by the first oscillating system 20, 22, 26 via a predetermined connecting means 28, and is also a dome. Shaped second diaphragm 32 and a second voice coil 3 formed at an end of the second diaphragm 32 and arranged in predetermined magnetic fluxes 6 and 8 in the first voice coil 26.
The second vibration systems 30 and 32 of 0 are provided.

In the present invention, the cone-shaped first
And the first vibration system 20, 22, 26 formed of the first voice coil 26 arranged in the predetermined magnetic flux 6, 8 formed at the end of the first diaphragm 20 and The second vibrating plate 52 and the second vibrating plate 52, which are held by the first vibrating system 20, 22, 26 via a predetermined connecting means 62 and have a cone shape smaller than the first vibrating plate 20, Second vibration systems 52, 56, 58 having second voice coils 56 formed at the ends and arranged in predetermined magnetic fluxes 6, 8 in the first voice coil 26 are provided.

[0022]

A second vibrating system 30 including a dome-shaped or cone-shaped second vibrating plate 32 or 52 held by the first vibrating system 20, 22, 26 via a predetermined connecting means 28 or 62, 32 or 52, 56, 58 to the first vibration system 2
Since the first diaphragm 20 having a cone shape is electromagnetically braked and driven at a constant current by following 0, 22, and 26, a coaxial speaker that can be driven at a constant current with a simple configuration that is easy to manufacture is provided. realizable.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 1 in which parts corresponding to those in FIG. 4 are designated by the same reference numerals, 40 denotes the coaxial speaker according to the present invention as a whole, and a bowl-shaped tweeter diaphragm 32 is provided in the gap between the coil bobbin 22 and the pole 8. Is fixed to the lower side of the inner peripheral surface of the woofer diaphragm 20 via a connecting portion 28 having a predetermined vibration transmissibility. The connecting portion 28 is adapted to maintain the frequency characteristics of the woofer diaphragm 20 and the tweeter diaphragm 32 during normal operation of the speaker 40.

At the outer end of the tweeter diaphragm 32, a secondary coil 30 is formed with a one-turn short-circuit coil structure in which the winding start and winding end are short-circuited. This secondary coil 3
0 is arranged at a position facing the plate 6, and thus the yoke 2, the magnet 4, the plate 6, the pole portion 8, the primary coil 26, and the secondary coil 30 form a magnetic circuit.

Further, in the case of this embodiment, the secondary coil 30 is constituted by a one-turn short-circuit coil having better heat conduction than the coil, so that it is prevented from being destroyed by the jule heat generated when the secondary coil 30 is driven. By doing so, the input withstand characteristics are improved.

Further, in this embodiment, the primary coil 26
As shown in FIG. 2, the transformer coupling coefficient between the secondary coil 30 and the secondary coil 30 is selected so that a drive current is generated in the secondary coil 30 mainly based on an audio signal in the mid-high range of about 1 [kHz] or more. , By this, woofer diaphragm 20 and tweeter diaphragm 3
The crossover frequency with 2 is selected to be about 1 [kHz].

Thus, the drive current based on the audio signal is conducted to the primary coil 26, so that the woofer diaphragm 2
0, the coil bobbin 22, the connecting portion 28, and the tweeter diaphragm 32 vibrate, thereby generating sound waves for each desired frequency band.

When the woofer diaphragm 20 vibrates excessively, the connecting portion 28 transmits this vibration to the secondary coil 30 formed on the tweeter diaphragm 32. This allows the secondary coil 3 of the tweeter diaphragm 32 to pass through the connecting portion 28.
An electromotive force is generated at 0 to generate an electromagnetic braking drive current that electromagnetically brakes excessive vibration generated in the secondary coil 30 in practical use.

In the above configuration, when the speaker 40 is driven by a constant voltage and / or a constant current, the primary coil 26
Is supplied to the drive current based on the audio signal. At this time, the primary coil 26 applies a force in the direction of arrow a or the opposite direction according to the Fleming left-hand rule to the coil bobbin 2 according to the drive current.
2 to the woofer diaphragm 20, so that the woofer diaphragm 20 vibrates so as to mainly generate sound waves in a predetermined middle and low range.

At this time, the primary coil 26 is transformer-coupled with the secondary coil 30 to generate a mid-high range driving current based on the mid-high range audio signal in the secondary coil 30. The coil 30 applies a force to the tweeter diaphragm 32 in the direction of arrow a according to Fleming's left-hand rule or in the opposite direction in accordance with the driving current for the mid-high range. Thus, the tweeter diaphragm 32 vibrates so as to mainly generate sound waves in a predetermined middle and high range.

In the case of this embodiment, the woofer diaphragm 20 vibrates so as to mainly generate sound waves in the mid-low range of about 1 [kHz] or less, and the tweeter vibration plate 32 produces mid-high range of about 1 [kHz] or more. It is designed to mainly generate sound waves in the region. Therefore, the speaker 40 as a whole can generate a sound wave based on the audio signal, and further, the suspension member for supporting the tweeter diaphragm 32 can be omitted.

Further, in the case of this coaxial speaker 40, since the woofer diaphragm 20 and the tweeter diaphragm 32 are connected by the connecting portion 28, the woofer diaphragm 20 and the tweeter diaphragm 32 vibrate independently in opposite phases. Since it is difficult to do so, the valley of the middle tone in the crossover frequency band becomes flat, so that the frequency characteristic of the entire speaker 40 can be improved.

Here, when the coaxial speaker 40 is driven with a constant current and, for example, excessive vibration is applied to the woofer diaphragm 20 by a driving current for generating a sound wave of the lowest resonance frequency, the connecting portion 28 drives the tweeter diaphragm 32. This excessive vibration is transmitted to the secondary coil 30 via. The secondary coil 30 to which excessive vibration is transmitted via the connecting portion 28 generates an electromotive force according to Fleming's right-hand rule in the secondary coil 30 according to the excessive vibration, and this electromotive force causes electromagnetic braking. The drive current flows through the secondary coil 30.

As a result, the secondary coil 30 is provided with an electromagnetic braking force which is in a direction opposite to the vibration direction of the excessive vibration and which can sufficiently brake the excessive vibration in practical use.
2. The vibration is transmitted to the woofer diaphragm 20 through the connecting portion 28 in sequence. Thus, the coaxial speaker 40 can sufficiently brake the excessive vibration generated in the woofer diaphragm 20 by this electromagnetic braking force in practical use, and the coaxial speaker 40 can be driven with a constant current.

Incidentally, in the tweeter diaphragm 32, the material of the vibrating portion of the tweeter diaphragm 32 can be selected in order to change the sound quality in the mid-high range or to increase the sensitivity.
Also, the same material as the woofer diaphragm 20 can be selected because it is integrally formed with the woofer diaphragm 20. In addition to the connecting portion 28, the tweeter diaphragm 32 and the coil bobbin 22 are also provided.
If a suspension is provided between the tweeter diaphragm 32 and the coil bobbin 22, it is possible to prevent the tweeter diaphragm 32 and the coil bobbin 22 from coming into contact with each other more reliably.

According to the above configuration, the tweeter diaphragm 32
The suspension member for independently supporting the speaker is omitted, and the magnetic circuit for electromagnetic braking is also used as the magnetic circuit of the speaker, so that the manufacturing is easy and the electromagnetic braking is applied. Thus, the coaxial speaker 40 that can be driven with a constant current can be realized.

In the above embodiment, the connecting portion 28
I described the case where is fixed to the woofer diaphragm 20,
The present invention is not limited to this, for example, by fixing the connecting portion to the coil bobbin 22, the same effect as that of the above-described embodiment can be realized.

Further, in the above-mentioned embodiment, the case where the connecting portion 28 is provided for connecting the woofer diaphragm 20 and the tweeter diaphragm 32 has been described, but the present invention is not limited to this, and the edge portion is not limited to this. You may make it connect using the diaphragm which has.

Incidentally, as shown in FIG. 3 in which parts corresponding to those in FIG. 1 are designated by the same reference numerals, the coaxial speaker 50 has an edge 52A at its end and adjusts sensitivity, sound quality and directivity in the middle and high range. The woofer diaphragm 20 and the tweeter vibration system 54 are connected by the diaphragm 52.

In this case, the tweeter vibration system 54 is composed of a bobbin 58 having a short-circuit coil 56 formed on the outer surface thereof and a dome-shaped cap vibration plate 60 fixed to the upper end of the bobbin 58. And woofer diaphragm 2
A damper 62 is interposed between the damper 62 and zero.

Thus, the diaphragm 52 and the tweeter vibration system 5
When the shape, size, and material of the diaphragm 52 are selected so that the diaphragm 4 and the tweeter vibrating system 54 vibrate together, the mechanical loss of the diaphragm 52 and the tweeter vibrating system 54 as a whole and mechanical loss can be adjusted. The sensitivity, sound quality and directivity in the mid-high range can be adjusted. Further, in the crossover frequency band, the woofer diaphragm 20 and the diaphragm 52 vibrate, so that the valley of the middle sound can be further flattened, and the frequency characteristics of the entire coaxial speaker 50 can be improved.

Further, in the above-described embodiment, the case where the ring-shaped connecting portion or the edge is used when connecting the tweeter diaphragm and the woofer diaphragm is described, but the structure of the connecting portion is not limited to this. Even if the connecting portion and the edge are formed intermittently, the same effect as that of the above-described embodiment can be realized.

[0044]

As described above, according to the present invention, a second vibrating system including a second vibrating plate having a dome shape or a cone shape which is held by the first vibrating system via a predetermined connecting means is provided. By driving the cone-shaped first diaphragm by electromagnetically braking the first vibration system to drive the constant current, a coaxial speaker capable of constant current driving with a simple structure that is easy to manufacture is provided. realizable.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of a coaxial speaker according to the present invention.

FIG. 2 is a characteristic curve diagram showing transformer coupling coefficients of the primary coil and the secondary coil of FIG.

FIG. 3 is a schematic cross-sectional view showing another embodiment of the coaxial speaker according to the present invention.

FIG. 4 is a schematic cross-sectional view showing a conventional coaxial speaker.

[Explanation of symbols]

1, 40, 50 ... Speaker, 4 ... Magnet, 6 ...
… Plates, 14, 56… Short-circuit coils, 20, 32,
52, 60 ... Vibration plate, 24, 26 ... Primary coil, 2
8 ... Connection part, 30 ... Secondary coil.

Claims (2)

[Claims] 1. A first vibrating system comprising a cone-shaped first vibrating plate and a first voice coil formed at an end portion of the first vibrating plate and arranged in a predetermined magnetic flux, and a predetermined vibrating system. Is held by the first vibrating system via the connecting means of the second vibrating plate and is formed at the end of the second vibrating plate and the second vibrating plate, and the predetermined voice coil is provided in the first voice coil. A second vibrating system composed of a second voice coil disposed in the magnetic flux of the second vibrating system, and the second vibrating system is driven by the first vibrating system to electromagnetically brake the first vibrating plate. A coaxial speaker characterized by being driven by a constant current. 2. A first vibrating system comprising a cone-shaped first vibrating plate and a first voice coil formed at an end of the first vibrating plate and arranged in a predetermined magnetic flux, and a predetermined vibrating system. And a second cone-shaped smaller than the first diaphragm while being held by the first vibrating system via the connecting means.
And a second vibrating system having a second voice coil formed at an end of the second vibrating plate and arranged in the predetermined magnetic flux in the first voice coil. A coaxial speaker characterized in that the second vibrating system is driven by the first vibrating system to electromagnetically brake the first vibrating plate for constant current driving.