JPH0649039Y2 - Electromagnetic sound transducer - Google Patents

Description

[Detailed Description of the Invention] (Industrial field of application) The present invention relates to an electromagnetic acoustic transducer in which a yoke is integrally provided at the base end of a wound pole and a diaphragm is made to face the tip of the pole. , A structure for winding a pole.

(Prior Art) FIG. 4 is a cross-sectional view showing a structure of a conventional electromagnetic acoustic transducer, 1 is a pole, 2 is a yoke integrally formed by fitting, bonding or integrally molding with the pole 1. , The pole 1 is provided with the winding 3, the yoke 2 is combined with the ring-shaped permanent magnet (or magnetic material) 4, and the yoke 2 and the permanent magnet 4 are combined.
A cylindrical case 5 is fixed to the periphery of the case 5, and a diaphragm 6 is attached to the end surface of the case 5 so as to face the tip of the pole 1.

In such an electromagnetic acoustic transducer, a self-bonding wire (that is, a metal wire whose surface is coated with a fusible resin) is used as the winding 3, and when the winding 3 is wound around the pole The block-shaped winding 3 is formed by melting the surface of the resin with a solvent such as alcohol or heat and winding the resin while adhering the coating resin on the adjacent portion of the winding.
The inner peripheral surface and the base end surface of the winding 3 are fixed to the pole 1 and the yoke 2 by the coating resin.

When an air-core coil is used as the winding 3, a block-shaped winding is formed by the self-bonding wire as described above, and the winding is fixed to the pole 1 and the yoke 2 with an adhesive to attach the winding. There is.

In the electromagnetic acoustic transducer having such a structure, the winding 3 is changed to the two-dot chain line a in FIG.
As shown in FIG. 3, the vibration plate 6 may come loose, which may cause a failure that the vibration plate 6 comes into contact with the tip surface of the winding 3 during vibration. Therefore, in order to eliminate the occurrence of such failures,
As shown in FIG. 5, a small diameter portion 1a is formed at the tip of the pole 1 in a stepped shape, and a winding pressing ring 7 is fitted to the small diameter portion 1a to control the displacement of the winding 3. As shown in the figure, the bobbin 8 is provided with the winding 3, and the bobbin 8 is fixed to the pole 1 and the yoke 3. Alternatively, as shown in FIG. By forming the height H2 to be lower than the height H1 of the pole 1, even if the winding 3 is displaced, the diaphragm 6 is not contacted.

(Problems to be solved by the invention) However, in the conventional structure shown in FIG.
The separate member is required to increase the number of parts, and the small diameter portion 1a must be processed or formed, and the pressing ring 7 must be fitted to the small diameter portion 1a.
Since the magnetic path cross-sectional area of the small-diameter portion 1a becomes narrow, there is a problem that the characteristics deteriorate.

Further, in the conventional structure shown in FIG. 6, since the bobbin 8 is used, there are problems that the cost is high and it is difficult to reduce the size.

Further, in the conventional structure of FIG. 7, an air-core coil is used as the winding 3, and in the case of direct winding shown in FIG. 5 and FIG. 6 (in the case of direct winding, an automatic winding machine is generally specified. The air core coil has to be manually twisted at its end, which is different from that of the winding at the terminal (not shown). There is a problem in that it takes a lot of time and labor, and it is easy to make a wiring error because of manual work.

In view of these problems, the present invention provides an electromagnetic acoustic transducer which prevents the diaphragm from coming into contact with the winding due to the displacement of the winding, which is advantageous in terms of manufacturing man-hours, manufacturing cost, and downsizing. With the goal.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides an electromagnetic sound conversion device in which a yoke is integrally provided at the base end of a pole with windings and a diaphragm is faced at the tip of the pole. In the container, the height of the tip end surface of the inner circumference of the winding is matched with the tip end surface of the pole, and the height of the tip end surface of the winding is gradually lowered from the inner circumference of the winding to the outer circumference. It is characterized by being formed.

(Function) The deviation of the winding from the diaphragm tends to be larger in the outer circumference of the winding than in the inner circumference. If the outer circumference of the winding is lowered as in the present invention, the deviation of the winding is Even if it occurs, it is difficult to contact the diaphragm. Further, since the inner circumference side of the winding is wound up to the tip of the pole, the number of turns increases.

(Embodiment) FIG. 1 is a front view showing an embodiment of the present invention, and FIG. 2 is a plan view thereof. As shown in FIGS. 1 and 2, in the present invention, the height of the tip surface of the inner peripheral portion of the winding 3 is made to coincide with the tip surface e of the pole 1, and the tip surface b of the winding 3 is It is formed so that the height becomes gradually lower from the inner peripheral portion of the winding 3 to the outer peripheral portion (ΔH in FIG. 1 indicates the difference in height between the inner peripheral portion and the outer peripheral portion of the winding 3).

According to this configuration, as shown in the two-dot chain line c, the displacement of the winding is often greater than the displacement of the inner peripheral portion in the pole axis direction of the outer peripheral portion. Even if the displacement occurs, it is possible to prevent the occurrence of the situation where the diaphragm contacts the winding 3.

In this winding structure, as shown in FIG. 3, a winding tip surface forming member 9 having an inclined surface d is applied to the tip of the pole 1, another holding member 10 is pressed from the yoke 2 side, and a driving device is used. While rotating, the self-bonding wire 12 is fed from the reel 11, and the winding 3 can be applied to the pole 1 while melting the surface by heat treatment or the like. Alternatively, an air-core coil may be formed in advance and fixed to the pole 1 and the yoke 2 with an adhesive to be attached.

(Effect of the Invention) According to the present invention, even if the winding is displaced, the diaphragm is prevented from coming into contact with the winding. In addition, the electromagnetic sound transducer is constructed without the need for a retaining ring or bobbin that prevents the winding from shifting, and the inner circumference of the winding is wound up to the tip side of the pole. It is possible to realize a small electromagnetic acoustic transducer having a small number of parts and a large number of turns with a wire diameter, which can reduce labor and man-hours, and further reduce manufacturing cost. Further, since the winding can be directly attached to the pole and it is not necessary to form a small diameter portion or the like, the characteristic becomes good.

[Brief description of drawings]

1 and 2 are a front view and a plan view showing an embodiment of an electromagnetic acoustic transducer according to the present invention, FIG. 3 is a side view showing a winding process of the embodiment, and FIG. 4 is a conventional view. FIG. 5 is a front view showing a conventional winding structure, FIG. 6 is a partially cutaway front view showing another example of the conventional winding structure, and FIG. It is a front view which shows another example of winding structure. 1: pole, 2: yoke, 3: winding, 4: permanent magnet, 5: case,
6: Vibration plate

Claims (1)

[Scope of utility model registration request] 1. An electromagnetic-acoustic transducer in which a yoke is integrally provided at a base end of a wound pole and a tip of the pole faces a diaphragm, and a height of a tip surface of an inner peripheral portion of the winding is increased. The electromagnetic acoustic transducer is characterized in that the height is matched with the tip surface of the pole and the height of the tip surface of the winding is gradually lowered from the inner peripheral portion to the outer peripheral portion of the winding.