JPS602635Y2 - electronic buzzer - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an electronic buzzer that generates vibration sound by vibrating a metal diaphragm through interaction between an alternating magnetic field and a direct current magnetic field.

Conventionally, this type of electronic buzzer has a wire-wound iron core placed upright in the center of a disc-shaped yoke, and a cylindrical permanent magnet magnetically attracted to the flat periphery of the yoke. There is one in which a metal diaphragm is adsorbed and mounted on the open end of the permanent magnet.

However, in this electronic buzzer, the number of parts is large because the yoke and the permanent magnet are individually machined.

In addition, the iron core can be set upright with respect to the yoke by forming a screw hole in the center of the yoke and screwing the lower end of the iron core with a thread into the screw hole, or by providing a through hole in the center of the yoke and inserting the screw thread into the screw hole. This is done by press-fitting or caulking the lower end of the iron core, which requires a large amount of processing and assembly man-hours, thereby avoiding high costs.

In addition, normally with an electronic buzzer, good vibration sound cannot be obtained unless the distance between the iron core and the diaphragm is set to a given dimension, but when fixing the iron core by screwing it to the yoke, The amount of screwing of the screwed portion must be adjusted, making assembly cumbersome and lacking in reliability.

In order to eliminate these drawbacks, the present invention aims to provide an electronic buzzer that reduces the number of parts and man-hours, facilitates assembly, and is highly reliable.

That is, in the electronic buzzer according to the present invention, the outer casing is molded from a homogeneous magnetic material into a cylindrical shape with a bottom that is integrated with the yoke, and the iron core of the electromagnet is placed in the center of the bottom of the outer casing by welding the lower end of the shaft. It is constructed by planting and fixing.

In this electronic buzzer, the number of parts and man-hours are reduced because the iron core is embedded in the bottom of the outer casing, and the iron core is inserted into the mold in advance when molding the outer casing. Since the planting position and height of the iron core can be controlled by the cavity surface, a structure that generates good vibration noise can be uniformly and easily obtained.

In addition, when molding the exterior casing, a hole of a predetermined shape is formed in the center of the bottom, and the lower end of the shaft of the iron core is inserted into the hole and glued or press-fitted, thereby planting the iron core in the center of the bottom of the exterior casing. It can also be fixed.

Even in this case, since the hole in which the iron core is planted can be formed as desired by molding, it becomes possible to precisely set the gap between the diaphragm and the iron core.

This will be explained below based on the illustrated embodiments.

The illustrated electronic buzzer vibrates a metal diaphragm 4 through the interaction of magnetic fields generated from an outer casing 1 made of a magnetic material and an iron core 3 provided with a winding 2, thereby producing vibration noise. It is configured so that it occurs.

The exterior casing 1 has a bottomed cylindrical shape in which a disc-shaped bottom part 1b is integrally molded at the lower end of a cylindrical body part 1a, and at both ends in the axial direction, for example, there is an N pole on the upper end side and a N pole on the bottom side. In this case, it is magnetized so that it is charged to the S pole and is shaped so that it acts as a permanent magnet.

As the magnetic material, a ferrite magnetic material or a mixed magnetic material of ferrite magnetic material and plastic is used, and the magnetic material is placed in a mold cavity and pressed under heat to form a bottomed cylindrical shape.

Note that it is appropriate that the mixing ratio of plastic and magnetic material be 20:8.

To mold the exterior casing 1, use the mold A.
Insert the iron core 3 so that the lower end of the shaft protrudes from the cavity surface.
can be loaded in advance.

In that case, the tip of the iron core 3 is connected to the outer casing 1.
The height is set so that it is located slightly inside the inner surface of the cavity forming the cylinder body portion 1a.

When the magnetic material is supplied into the cavity of the mold B in this state and compressed, the iron core 3 is planted and fixed in the center of the casing bottom 1b simultaneously with the molding of the outer casing 1.

When molding this exterior casing 1, a terminal pin 5, which will be described later, is used.
The through-hole 1c and the fitting stepped portion 1d of the capping 7 are also formed.

A desired number of terminal pins 5 fixed upright to the printed circuit board 6 are fitted into the thus obtained exterior casing 1 so as to project outward from the through holes 1c.

An opening 6a into which the iron core 3 is inserted is formed in the printed circuit board, and the iron core 3 is mounted by inserting it into the through hole.

A winding 2 previously formed into a coil is inserted into the iron core 3 to form an electromagnet.

The lead wire 2a of the winding 2 is connected to the base of a terminal pin 5 protruding from the lower surface of the substrate 6, and the winding 2 is excited by an alternating current supplied from this terminal pin.

The diaphragm 4 is made of metal and is shaped like a disk, and is attracted onto the opening periphery of the exterior casing 1, which is a permanent magnet, at a constant distance from the tip of the iron core 3 of the electromagnet.

The opening side of the exterior casing 1 can be covered by fitting a resin capping 7 onto the stepped portion 1d, and a through hole 7a through which vibration sound passes is formed in the center of the capping 7. There is.

In the electronic buzzer configured in this manner, when an alternating current is passed through the winding 2, the interaction between the alternating magnetic field generated in the iron core 3 serving as the magnetic core and the direct current bias magnetic field of the exterior casing 1 causes the diaphragm 4 to move upward and downward. It vibrates downward and generates a vibration sound.

At this time, the current flowing through the winding 2 is applied with a DC magnetic bias by the permanent magnet of the outer casing 1, so an extremely small current is sufficient.

Also, the vibration noise generated is caused by the iron core of the electromagnet. Since the cappings 7 are kept at a constant distance from each other so as not to collide with each other, good sound with less distortion depending only on the vibration of the diaphragm 4 can be obtained.

Furthermore, when the outer casing is made of a mixture of plastic and magnetic material, the bottom of the casing is relatively flexible or elastic, which acts as an acoustic damper for the diaphragm and dampens vibrations. It absorbs the harmonic distortion contained in the sound and generates high-quality vibration sound.

As described above, according to the electronic buzzer according to the present invention, since the outer casing is formed into a cylinder shape with a bottom and the yoke is integrally molded with a magnetic material, the number of parts and assembly time is 9 compared to the conventional one. In addition to making it possible to reduce costs by reducing the amount of iron, the lower end of the shaft is carved into the bottom surface, which can be accurately formed by molding, and the iron core is planted and fixed, increasing the accuracy of the finish and increasing the reliability of the product. It has been improved.

[Brief explanation of the drawing]

The drawings show one embodiment of the electronic buzzer according to the present invention, FIG. 1 is a sectional view thereof, FIG. 2 is a schematic explanatory diagram showing molding of the outer casing, and FIG. 3 is a developed view of the first illustrated buzzer. It is. DESCRIPTION OF SYMBOLS 1... Exterior casing, 1b... Bottom of the exterior casing, 1d... Step part of the outer periphery of the exterior casing, 2...
Winding wire, 3... iron core, 4... diaphragm, 7... capping.

Claims (4)

[Scope of utility model registration request] (1) An electronic buzzer in which an electromagnet made of a wire wound around an iron core is formed of a permanent magnet and placed inside the exterior casing, and the magnetic interaction of these magnets vibrates a diaphragm that is attracted to the periphery of the opening of the exterior casing. An electronic buzzer characterized in that the outer casing is molded into a bottomed cylinder shape with a magnetic material, and the iron core of the electromagnet is planted and fixed in the center of the bottom of the outer casing by welding the lower end of the shaft. (2) The electronic buzzer according to claim 1, wherein the outer casing is made of a ferrite magnetic material. (3) The electronic buzzer according to claim 1, wherein the outer casing is made of a mixed magnetic material of plastic and magnetic material. (4) The above-mentioned exterior casing has a stepped bottom shape on the outer periphery of the open end so that a capping having a through hole formed in the central plane can be fitted and fixed thereto. The electronic buzzer described in Scope 1.