JPH0522795A - Speaker - Google Patents

Abstract

PURPOSE:To obtain a speaker having the excellent acoustic output characteristic free from the distortions by stabilizing the magnetic flux in a magnetic gap. CONSTITUTION:An auxiliary coil 9 connected in parallel or series to a voice coil 6 is provided at the upper part of the inner circumferential part of a magnetic gap 8. Thus a current of the reversed polarity flows in the direction where the magnetic flux generated by the current flowing to the coil 6 is eliminated. As a result, the magnetic flux generated in the gap 8 can always be stabilized. Thus the distortions can be extremely reduced for the acoustic output characteristic of a speaker.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speaker used in various audio equipment.

[0002]

2. Description of the Related Art In recent years, due to the digitization of audio equipment, high-quality sources (CD, DAT) over the entire audio band have been recorded.
Etc. have been put to practical use, but many distortions still occur in a speaker that converts a music signal from an electric signal to an acoustic output. The strain generated in the speaker can be roughly classified into three types, which are a strain caused by a drive system, a strain caused by a support system, and a strain caused by a diaphragm. Among these, an effective method for improving the distortion by the drive system has not been found.

The conventional speaker will be described below with reference to the drawings. FIG. 2 is a half cross-sectional view showing a structure of a speaker using a flat diaphragm in a conventional speaker, including a lower plate 1 having a center pole 7,
Ring-shaped magnet 2 and ring-shaped upper plate 3
To form a magnetic gap 8 to form a magnetic circuit. A baffle plate 4 is coupled to this magnetic circuit, and a peripheral edge portion of an edge 9 coupled to a peripheral edge portion of a diaphragm 5 in which a voice coil 6 is coupled to a lower central portion is fixed to an inner peripheral side of an upper surface of the baffle plate 4 and The voice coil 6 is fitted in the magnetic gap 8.

When a current flows through the voice coil 6 fitted in the magnetic gap 8 of the conventional speaker thus constructed, the magnetic flux in the magnetic gap 8 drives the voice coil 6 according to Fleming's left-hand rule. The force acts in the vertical direction to drive the diaphragm 5 to which the voice coil 6 is coupled to generate a sound wave, and the sound wave is electro-acoustic converted.

[0005]

However, in the above-mentioned conventional configuration, the magnetic flux generated in the magnetic gap 8 by the magnetomotive force of the magnet 2 when a current flows through the voice coil 6 (static and does not fluctuate with time). ) Is the magnetic flux generated by the current flowing through the voice coil 6 (dynamic and fluctuating)
Therefore, the voice coil 6 cannot obtain a driving force proportional to the flowing current because it changes under the influence of. Therefore,
The obtained acoustic output characteristic becomes distorted, and there is a problem that this is a fundamental problem due to the drive system that cannot be solved by improving the diaphragm 5 and the support system.

It is an object of the present invention to solve the above problems and to provide a speaker that stabilizes the magnetic flux in the magnetic gap and has excellent acoustic output characteristics without distortion.

[0007]

In order to solve the above-mentioned problems, a speaker according to the present invention has an outer peripheral portion of a diaphragm in which a frame is coupled to a magnetic circuit having a magnetic gap and a voice coil fitted in the magnetic gap is coupled. Is fixed to a frame, and an auxiliary coil formed by winding a good conductor such as a copper wire two or more times around the inner peripheral portion of the magnetic gap is connected to the voice coil, and the voice coil is attached to the auxiliary coil. The signal of the same magnitude and the opposite polarity to the signal to be input to is input.

[0008]

With this configuration, the auxiliary coil provided above the inner peripheral portion of the magnetic gap has a current of opposite polarity flowing in a direction of canceling the magnetic flux generated by the current flowing in the voice coil, and a current in the opposite direction of the magnetic flux. Magnetic flux is generated.
As a result, the magnetic flux generated by the electric signal input to the voice coil is canceled out, and the constant magnetic flux generated by the magnetomotive force of the magnet is stabilized in the magnetic gap even when the electric signal is input to the voice coil. Can occur. Therefore, the obtained acoustic output characteristics have improved distortion caused by the drive system.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. In addition, the same reference numerals are given to the components having the same configurations as those of the conventional example.

FIG. 1 is a half cross-sectional view showing the structure of a speaker according to an embodiment of the present invention, in which a lower plate 1 having a center pole 7, a ring-shaped magnet 2 and a ring-shaped upper plate 3 are combined. A magnetic circuit in which the magnetic gap 8 is formed. A baffle plate 4 is coupled to this magnetic circuit, and a peripheral edge portion of an edge 9 coupled to a peripheral edge portion of a diaphragm 5 in which a voice coil 6 is coupled to a lower central portion is fixed to an inner peripheral side of an upper surface of the baffle plate 4 and The voice coil 6 is fitted in the magnetic gap 8.

An auxiliary coil 10 formed by winding a good conductor such as a copper wire twice or more is mounted on the upper portion of the inner peripheral portion of the magnetic gap 8. The auxiliary coil 10 is connected so that a signal having a polarity opposite to that of the signal input to the voice coil 6 and having a similar level is input.
Either parallel or series is connected depending on whether the winding direction of the auxiliary coil 10 is the same as or different from the winding direction of the voice coil 6.

The loudspeaker of the present invention thus constructed is constructed such that the magnetic flux generated when a current flows through the voice coil 6 applies a signal having a polarity opposite to that of the signal input to the voice coil 6. It is canceled by the generated magnetic flux in the auxiliary coil 10. Therefore, the magnetic flux generated in the magnetic gap 8 due to the magnetomotive force of the magnet 2 can always maintain a constant value even when the voice coil 6 is driven, and the voice coil 6 can be kept in a stable state. It is stably driven by the constant magnetic flux generated inside.

[0013]

As described above, in the speaker according to the present invention, even if the magnetic flux generated by the current flowing in the voice coil fluctuates momentarily, the magnetic flux generated in the magnetic gap is not affected and the voice coil flows. It becomes possible to generate a driving force proportional to the current, and it is possible to greatly reduce the distortion caused by the driving system.

[Brief description of drawings]

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

FIG. 2 is a half sectional view showing a configuration of a conventional speaker.

[Explanation of symbols]

 1 Lower Plate 2 Magnet 3 Upper Plate 4 Baffle Plate 5 Vibration Plate 6 Voice Coil 7 Center Pole 8 Magnetic Gap 9 Edge 10 Auxiliary Coil

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Naoyuki Ozawa 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (1)

Claim: What is claimed is: 1. A frame is coupled to a magnetic circuit having a magnetic gap, and an outer peripheral portion of a diaphragm, to which a voice coil fitted in the magnetic gap is coupled, is fixed to the frame. A speaker provided with an auxiliary coil formed by winding a good conductor such as a copper wire two or more times on the upper part of the peripheral portion in parallel or in series with the voice coil.