JPH0761200B2 - Speaker - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speaker, and more particularly to a speaker capable of reproducing a wide frequency range with a simple structure.

[0002]

2. Description of the Related Art As an audio speaker, there is a so-called core-type speaker in which a plurality of speakers having different reproduction bands are arranged on the same axis. As a conventional example of the coaxial loudspeaker, there is known one having a structure in which a tweeter is arranged at a position coaxial with the woofer, for example, a space inside a voice coil. In this coaxial loudspeaker, since the woofer and the tweeter are arranged with the same axis, the sound waves in both the low frequency region and the high frequency region are reproduced as if they were generated from the same sound source. Therefore, it has a good sound field reproduction capability.

[0003]

Since the speaker of the above-mentioned conventional example has a structure in which the tweeter is arranged inside the voice coil of the woofer, the magnet of the tweeter, the voice coil, and the vibration are provided in this limited space. There is a problem that it is necessary to provide a plate, and there are many design restrictions. Further, in this method, since the two speakers are arranged extremely close to each other, it is inevitable that the powerful magnetic circuit of the woofer adversely affects the magnetic circuit of the tweeter.

In consideration of the above problems, a speaker as shown in FIGS. 9 to 11 has been proposed. In the figure, reference numeral 1 is a magnet, reference numeral 2 is a pole piece, reference numeral 3 is a voice coil, reference numeral 4 is a woofer diaphragm, and reference numeral 5 is an elastic suspension that supports the diaphragm 4. Inside the voice coil 3, a tweeter vibrating body 6 as shown in FIGS. 10 and 11 is provided. This tweeter vibrator 6
Is made of a conductive material such as metal and is composed of a vibrating plate portion 7 having a spherical shape and a cylindrical skirt portion 8 provided around the vibrating plate portion 7. The tweeter vibrating body 6 is supported by a shaft 9 fixed to the pole piece 2 via a tweeter suspension 10 made of an elastic body. A reflector 11 is fixed to the tip of the shaft 9 so as to correct the phase of the sound wave generated from the tweeter vibrating body 6.

In the above speaker, the skirt portion 8 of the tweeter vibrating body 6 has a function as a one-turn coil, and the voice coil 3 inducts an electric current. That is, a transformer having the voice coil 3 as a primary coil and the skirt portion 8 as a secondary coil is formed.

In the speaker having the above structure, the woofer diaphragm 4 is driven by the signal flowing through the voice coil 3 at a frequency of several thousand kilohertz or less, and
In a high frequency range where the woofer diaphragm 4 is less likely to vibrate, the impedance of the voice coil 3 is lowered, and the tweeter vibrating body 6 starts to move as the current increases. Therefore, a low frequency is reproduced from the woofer diaphragm 4 without using a special frequency division circuit,
A high frequency can be reproduced from the tweeter vibrating body 6.

However, the tweeter vibrator 6 is
Since it is necessary to perform both the function as the diaphragm and the function as the coil, the special shape shown in the figure is unavoidable, and there is a problem that the degree of freedom in selecting the shape of the diaphragm or the material is small. is there. In addition, when the diaphragm is made of a conductive material such as a metal, an increase in weight is inevitable, and it becomes difficult to drive the coil by a one-turn coil. There is a problem that the responsiveness to is poor. Further, there is a problem that the tweeter diaphragm 6 must be provided inside the voice coil 3 in a limited range.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to reduce the weight of a diaphragm for a high frequency region and obtain a speaker with good response.

[0009]

In order to achieve the above object, the present invention provides a first vibrating plate integrally connected to a voice coil by supplying a signal to the voice coil placed in a magnetic field. In a speaker that is driven according to the signal, the magnetic flux generated from the voice coil
Made of a ferromagnetic material that receives attractive force or repulsive force between and
The second diaphragm is used as the voice coil and the first vibrating plate.
It is possible to move with respect to the voice coil as much as possible
It is characterized in that it is provided in a close position.
It

[0010]

In the region where the impedance of the first diaphragm is low, the current of the voice coil increases, and the magnetic field generated by this current drives the second diaphragm.

[0011]

Embodiments of the invention will be described below with reference to the drawings. In the figure, the same parts as those in the conventional example are designated by the same reference numerals to simplify the description.

1 and 2 show a first embodiment of the present invention. Reference numeral 20 denotes a tweeter diaphragm, which is fixed to the upper surface of the pole piece 2 via a suspension 21. The diaphragm 2
0 is a thin plate or film made of a ferromagnetic material such as steel. As shown in FIG. 2, the front surface is the S pole and the back surface (the surface on the pole piece side) is the N pole. It is magnetized. The material of the vibrating plate 20 is not limited to a metal plate or a metal thin film, and any magnetic substance that can be magnetized may be used. For example, a film of resin such as polyester to which magnetic substance powder such as ferrite is attached. May be The suspension 21 movably supports the tweeter diaphragm 20 with respect to the pole piece 2 and the like, and is made of an elastically deformable material such as rubber or synthetic resin. In addition, the suspension 21 in the illustrated example
Is formed into a bellows shape having a plurality of bent portions so as to be easily elastically deformed.
Other materials, for example, a resin material in a foamed state such as sponge or Styrofoam may be used as long as 0 can be movably supported.

In the thus constructed speaker, the voice coil 3 is supplied with the drive current.
Is excited, and the diaphragm 4 is driven by the force acting on the voice coil 3 in the magnetic path between the permanent magnet 1 and the pole piece 2.
Is driven. The diaphragm 4 is usually formed with a diameter of several centimeters to several tens of centimeters,
In the case of such a diameter, due to its own mechanical vibration characteristics,
At frequencies below a few thousand kilohertz, it can be vibrated by the signal flowing through the voice coil 3. Also,
At a high frequency exceeding this, the woofer diaphragm 4 is less likely to vibrate, the impedance of the voice coil 3 is lowered and the current is increased, and the leakage magnetic flux is increased, which results in tweeter vibration made of a ferromagnetic material. The plate 20 starts to vibrate. Therefore, a low frequency can be reproduced from the woofer diaphragm 4 and a high frequency can be reproduced from the tweeter diaphragm 20 without using a special frequency division circuit. Further, the crossover frequency between the woofer and the tweeter can be variously set by appropriately setting the material, weight, and shape of the respective diaphragms or suspensions to obtain the required compliance.

FIG. 3 shows a second embodiment. In this embodiment, the tweeter diaphragm 20 is not positively magnetized, and even if the tweeter diaphragm 20 is not magnetized, depending on the permanent magnetic pole property (usually N pole) of the tip of the pole piece 2, it is illustrated. Thus, the magnetic field generated from the voice coil 3 can be oscillated as in the case of the first embodiment.

FIG. 4 shows a third embodiment. In the third embodiment, a slit 23 is formed in a part of the tweeter diaphragm 22.
Is provided, the effect of the one-turn coil when the tweeter diaphragm 22 is formed of a conductor is eliminated, the loss caused by the current flowing through the coil is prevented, and the coil 3 is driven. It is possible to prevent the efficiency of the woofer diaphragm 4 itself from decreasing.

FIG. 5 shows a fourth embodiment. In the fourth embodiment, the tweeter vibrating plate 24 having a convex surface is used. By adopting such a shape, the high frequency sound wave generated from the tweeter vibrating plate 24 can be diffused in a wide range. You can

FIG. 6 shows a fifth embodiment. In the fifth embodiment, the tweeter vibrating plate 25 whose front side is concave is used. With such a shape, the high-frequency sound wave generated from the tweeter diaphragm 24 is directed in a specific direction. It can have sex.

7 and 8 show a sixth embodiment. In the sixth embodiment, a hole 27 is provided in the center of the tweeter diaphragm 26, and a super tweeter diaphragm 28 is provided in the hole 27 to form a three-way structure.

The tweeter diaphragm 26 and the super tweeter diaphragm 28 are supported by the tips of the pole pieces 2 via suspensions 29 and 30, respectively, so that they can vibrate independently. Tweeter diaphragm 2
6 and the super tweeter diaphragm 28 can be set to various reproduction frequency bands by appropriately setting the material, weight, and shape of each diaphragm or suspension to obtain the required compliance.

Although the second diaphragm is supported by the pole piece by the suspension in the above embodiment, another structure may be adopted without departing from the scope of the present invention. In addition, it goes without saying that the specific shape of each diaphragm is not limited to the above-mentioned embodiment.

[0021]

As is apparent from the above description, the present invention is
Since the second diaphragm made of a ferromagnetic material is provided in the vicinity of the voice coil of the speaker so as to be movable with respect to the first diaphragm integrated with the voice coil, it is possible to obtain a good sound that the conventional core-axial speaker has. It goes without saying that the principle of movement is when the current of the voice coil increases in the region where the impedance of the first diaphragm decreases and the magnetic field generated by this current drives the second diaphragm The following effects can be obtained based on the operation in. a. Since the second diaphragm vibrates in a region where the impedance of the first diaphragm is small, the first and second diaphragms are respectively provided in a predetermined frequency band without providing a special frequency division circuit in the drive circuit. Can be driven by
Therefore, a multi-way speaker with a simple structure can be obtained. b. The second diaphragm may be made of any material and shape as long as it is a ferromagnetic material and elastically deformable. Therefore, it is easy to process and the production cost is low. c. Since the degree of freedom in selecting the shape and material of the second diaphragm is high, it is possible to easily reduce the weight, and therefore the response to a minute signal is good. d. It is possible to easily manufacture not only a two-way type, but also a multi-band type such as a three-way type or a four-way type.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a speaker according to a first embodiment.

FIG. 2 is a first embodiment.

FIG. 3 is a vertical sectional view of a diaphragm of a speaker according to a second embodiment.

FIG. 4 is a perspective view of a diaphragm of a speaker according to a third embodiment.

FIG. 5 is a vertical sectional view of a speaker according to a fourth embodiment.

FIG. 6 is a vertical sectional view of a speaker according to a fifth embodiment.

FIG. 7 is a perspective view of a diaphragm of a speaker according to a sixth embodiment.

FIG. 8 is a vertical sectional view of a diaphragm of a speaker according to a sixth embodiment.

FIG. 9 is a vertical cross-sectional view of a conventional example of a coaxial speaker.

FIG. 10 is a perspective view of a tweeter vibrating body of the core axial speaker of FIG.

11 is a vertical cross-sectional view of a tweeter vibrating body of the core axial speaker of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 magnet 2 pole piece 3 voice coil 4 diaphragm (first diaphragm) 20 diaphragm (second diaphragm) 21 tweeter suspension 22 diaphragm (second diaphragm) 23 slit 24 diaphragm (second diaphragm) Vibration plate 25 Vibration plate (second vibration plate) 26 Vibration plate (second vibration plate) 28 Vibration plate (third vibration plate)

Claims (1)

[Claims] Signal by supplying to 1. A voice coil placed in a magnetic field, in a speaker, to the first vibration plate integrally connected to the voice coil is driven in response to the signal, the Magnetic flux generated from the voice coil
Made of a ferromagnetic material that receives attractive force or repulsive force between and
The second diaphragm is used as the voice coil and the first vibrating plate.
It is possible to move with respect to the voice coil as much as possible
A speaker characterized by being provided in close proximity to each other.