JPH0744156Y2 - Acoustic transducer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application) The present invention relates to an acoustic transducer, and more particularly to a structure of a magnetic circuit of an acoustic transducer in which a conductor is fixed on a film or ribbon diaphragm and an arrangement of the diaphragm. It is a thing.

(Problems to be Solved by the Related Art and Invention) Conventionally, as a flat speaker, a film-like diaphragm provided with a conductor and being electrokinetically coupled with a magnetic circuit, or a ribbon conductor provided with a magnetic circuit is provided. An acoustically coupled acoustic transducer has been proposed, but it has drawbacks such as a loose coupling between the conductor and the magnetic circuit and low magnetic efficiency, and a complicated structure to make the magnetic efficiency dense. .

For example, FIGS. 2 (a), 2 (b) and 2 (c) are schematic views of a semi-cut section of a conventional acoustic transducer.

2 (a), (b) and (c), a magnetic circuit is constituted by the permanent magnet 1, the center pole 2, the yoke 3 and the plate 4, respectively, and the coil 5 is placed at a position intersecting with the magnetic flux of the magnetic circuit. Is fixed to the vibrating plate 6, and the vibrating plate 6 is fixed to the plate 4 at its peripheral portion by appropriate means.

2 (a) has a simple structure, but only the leakage magnetic flux of the magnetic circuit intersects with the coil 5, so that the magnetic efficiency is poor and the required output cannot be obtained.

Further, FIG. 2 (b) shows that the plate 4'having substantially the same shape is provided in addition to the plate 4, and the magnetic efficiency is improved, but two plates 4, 4'are required, and the structure is complicated. Is.

Further, in FIG. 2 (c), the magnetic efficiency is improved by providing the projection 4 ″ on the inner circumference of the plate 4, but since the magnetic circuit is assembled independently due to the structure, it is difficult to reproduce in the case of failure. is there.

As described above, the conventional acoustic transducers have their respective drawbacks.

It is an object of the present invention to solve the above problems and provide a highly efficient and inexpensive acoustic transducer.

(Means for Solving the Problem) In order to achieve the above-mentioned object, the present invention is provided with a center pole 2 provided at the center of a disk-shaped yoke 3 and the yoke 3.
Acoustic conversion in which a conductor is provided on a film or ribbon diaphragm, which includes a magnetic circuit configured by a ring-shaped permanent magnet 1 provided above and a ring-shaped plate 4 provided on the permanent magnet 1. In the container, a ring-shaped auxiliary plate 4a is provided on the plate 4, the inner diameter of the auxiliary plate is smaller than the inner diameter of the plate 4, and the coil 5 is provided at the lower end of the inner periphery of the auxiliary plate 4a. The outer peripheral portion of the disc-shaped diaphragm 6 is fixed, and the diameter of the diaphragm 6 is smaller than the inner diameter of the plate 4, and the height from the upper surface of the yoke 3 to the top 2'of the center pole 2 is The gist of the acoustic transducer is that the height from the upper surface of the yoke 3 to the lower end of the inner periphery of the auxiliary plate 4a is lower than the height.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.
It is needless to say that the embodiment is merely an example, and various modifications and improvements can be made without departing from the spirit of the present invention.

1 (a) and 1 (b) are half-cut sectional views of an acoustic transducer showing an embodiment of the present invention. Here, (a) shows that the auxiliary ring 7a of the diaphragm 6 is attached to the lower part of the diaphragm 6,
In (b), the auxiliary ring 7a is attached to the upper part of the diaphragm 6, and other configurations are the same, so (a) will be mainly described below. In the figure, the permanent magnet 1, the center pole 2, the yoke 3, and the plate 4 are magnetic circuits having basically the same structure as the conventional example.

That is, a center pole 2 protruding upward is provided at the center of a disk-shaped yoke 3, a ring-shaped permanent magnet 1 is provided on the outer peripheral portion of the yoke 3, and a ring-shaped plate 4 is provided on the permanent magnet 1. A magnetic circuit is provided by these components, a conductor is provided on the film or ribbon diaphragm, and the conductor is placed in the magnetic circuit to form an acoustic transducer.

Further, an auxiliary plate 4a having an inner diameter smaller than the inner diameter of the plate 4 is provided on the upper edge of the plate 4, and the outer periphery of the diaphragm 6 provided with the coil 5 is fixed to the inner peripheral lower end portion 7 of the auxiliary plate 4a. The outer circumference of the diaphragm 6 is protected by an auxiliary ring 7a, and the inner diameter of the plate 4 is larger than the outer circumference of the diaphragm 6. Further, the lower end 4 of the auxiliary plate 4a
The top portion 2'of the center pole 2 has a structure lower than the height a'by a height δ. Further, this δ is the diaphragm 6
Is set so as to secure a space in which vibration is possible.

In such a structure, the permanent magnet 1, the center pole 2,
The yoke 3 and the plate 4 are independently assembled, and the diaphragm 6 with the reinforcing ring 7a is fixed to the inner peripheral lower end portion 7 of the auxiliary plate 4a. In FIG. The vibration plate 6 is fixed directly to the auxiliary plate 4a because it is attached to the lower part of the
Since 7a is attached to the upper part of diaphragm 6, reinforcing plate 4a
Will be fixed to this through the reinforcing ring 7a.
Thus, the auxiliary plate 4a with the vibrating plate 6 and the magnetic circuit, which are separately assembled, are assembled. Therefore, the magnetic flux is concentrated on the center pole 2 through the plate 4 and the auxiliary plate 4a, and by positioning the coil 5 in the magnetic flux, the magnetic efficiency is improved and the magnetic circuit is independently assembled and assisted. The diaphragm 6 is fixed to the plate 4a, and both are assembled to facilitate manufacturing. Further, the readjustment due to a defect or the like has an advantage that the magnetic circuit and the diaphragm can be individually performed.

Although the film-shaped diaphragm is described in the embodiment, the same effect can be obtained by applying the present invention to a ribbon-shaped diaphragm.

(Effect of the Invention) As described above, the present invention has the center pole 2 provided at the center of the disk-shaped yoke 3, the ring-shaped permanent magnet 1 provided on the yoke 3, and the permanent magnet. 1. An acoustic transducer provided with a conductor on a film or ribbon diaphragm, which comprises a magnetic circuit composed of a ring-shaped plate 4 provided on the plate 1, and a ring-shaped auxiliary plate 4a on the plate 4. The inner diameter of the auxiliary plate is smaller than the inner diameter of the plate 4, and the outer peripheral portion of the disk-shaped diaphragm 6 provided with the coil 5 is fixed to the lower end portion of the inner peripheral portion of the auxiliary plate 4a. The diameter of the plate 6 is smaller than the inner diameter of the plate 4, and the height from the upper surface of the yoke 3 to the top 2'of the center pole 2 is from the upper surface of the yoke 3 to the lower end of the inner circumference of the auxiliary plate 4a. of By lowering the height, the magnetic efficiency is high,
In addition, it is possible to provide an acoustic transducer that is easy to assemble, inexpensive, and easy to work during maintenance.

[Brief description of drawings]

1 (a) and 1 (b) are half cutaway views showing an embodiment of the present invention, and FIGS. 2 (a), 2 (b) and 2 (c) are schematic cutaway views of a conventional acoustic transducer. is there. 1 ... Permanent magnet 2 ... Center pole 3 ... Yoke 4 ... Plate 4a ... Auxiliary plate 5 ... Coil 6 ... Vibration plate 7 ... Lower end 7a ... Reinforcement ring

Claims (1)

[Scope of utility model registration request] 1. A center pole (2) provided in the center of a disk-shaped yoke (3), a ring-shaped permanent magnet (1) provided on the yoke (3), and this permanent magnet ( 1) An acoustic transducer provided with a conductor on a film or ribbon diaphragm, comprising a magnetic circuit constituted by a ring-shaped plate (4) provided on the plate (4), -Shaped auxiliary plate (4a) is provided, the inner diameter of this auxiliary plate is smaller than the inner diameter of the plate (4), and the disk-shaped auxiliary plate (4a) is provided with the coil (5) at the lower end of the inner circumference. The outer peripheral portion of the diaphragm (6) is fixed, and the diameter of the diaphragm (6) is smaller than the inner diameter of the plate (4), and the center pole (2) is attached to the upper surface of the yoke (3).
The acoustic transducer characterized in that the height to the top (2 ') of the is lower than the height from the upper surface of the yoke (3) to the inner peripheral lower end of the auxiliary plate (4a).