JPS5845791B2 - induction heating device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an induction heating device, and more particularly, the present invention relates to an induction heating device, in which a heated object made of a metallic material is placed in an alternating magnetic field, and the eddy current product generated in the heated object due to electromagnetic induction is calculated. The present invention relates to an induction heating device that heats by inducing heat loss.

In general, in induction heating devices, it is known that the inductor coil vibrates in the radial direction due to its heating principle, and sound is emitted to the outside, resulting in a large noise source.

FIG. 1 is an illustrative view showing an example of a conventional induction heating device.

In the figure, an inner cylinder 1 is formed into a main cylindrical shape capable of storing a heated object 2 therein, and is made of heat-resistant concrete.

An induction heating device is constructed by winding an inductor coil 3 of the same shape around the outer periphery of this inner cylinder 1.

With the above configuration, (1) When a power source with a predetermined frequency flows through the induction coil (3), the heated object (2) within the alternating magnetic field generated by this generates heat due to the so-called eddy current product and hypothermic loss. do.

At the same time, the inductor coil 3 vibrates in a loop in the radial direction at a frequency twice the power supply frequency.

For this reason, the conventional induction heating device has a drawback in that sound is emitted from the surface of the outer diameter of the induction coil 3 and generates a large amount of noise.

The present invention has been made to overcome the above-mentioned drawbacks, and an object of the present invention is to provide an induction heating device that can reduce noise caused by vibration of an inductor coil.

FIG. 2 is an illustrative view of an induction heating device according to an embodiment of the present invention.

As shown in the figure, the inner cylinder 1 is formed into a cylindrical shape so that a heated object 2 can be housed therein, and is made of heat-resistant concrete as an example of its material.

An inductor coil 3 and an inductor coil 4 having the same shape are alternately wound around the outer periphery of the inner cylinder 1 along the section direction.

In order to shift the difference in the outer peripheral surfaces of the inductor coils 3 and 4 by a length l, a portion on the outer periphery of the inner cylinder 1 around which the inductor coil 4 is wound is formed to protrude.

The difference l between the outer peripheral surfaces of the inductor coils 3 and 4 is 1/2 the wavelength of the generated sound, that is, the sound with a frequency twice the power supply voltage.
Selected to shift.

In the above configuration, (1) if we consider the case where a power supply current of a predetermined frequency is passed through the inductor coils 3 and 4, a force in the radial direction of the inductor coils 3 and 4 is generated due to electromagnetic induction.

In particular, the radial force on the inductor coils 3, 4 causes them to vibrate at a frequency twice the power supply frequency.

This vibration causes sound to be emitted from the outer circumferences of the inductor coils 3 and 4 in the radial direction.

Here, the radius of the outer surface of the inductor coil 3 and the radius of the inductor coil 4
The difference l between the radius of the outer surface of The phase difference with that is 180°.

Therefore, when sounds with a phase difference of 180° are synthesized, both sounds cancel each other out, resulting in lower sound pressure and noise than in the conventional type.

FIG. 3 is an illustrative view of an induction heating device according to another embodiment of the present invention.

This embodiment differs from FIG. 2 in that the outer circumferential shape of the inner cylinder 1 is made uniform, and two types of inductor coils 3 and 5 having different shapes are alternately wound.

That is, the inductor coil 5 is configured so that its radial size differs from the inductor coil 3 by a length l, and the length l is changed as shown in FIG. 2 above due to the difference in the shape of the inductor coil itself. This is a predetermined value.

FIG. 4 is an illustrative view of an induction heating device according to another embodiment of the present invention.

This embodiment differs from FIG. 2 in that inductor coils 3 and 5 with different radial thicknesses are used, and the outer periphery of the inner cylinder 1 around which the inductor coil 5 is wound protrudes by a thickness m. The inductor coils 3 and 5 are formed so that the sum of the difference in thickness in the radial direction and the thickness m is l.

The value of the thickness m formed on the outer circumferential portion of the inner cylinder 1 is:
The vibration is selected so that the frequency of vibration twice the power supply frequency is half the wavelength of the elastic wave transmitted through the material of the inner cylinder 1.

With this configuration, the sound transmitted in the radial direction of the inner cylinder 1 can also be reduced in the same way as the principle explained in FIG. 2 above.
Since the sounds emitted from the inductor coils 3 and 5 cancel each other out, noise can be reduced.

FIG. 5 is an illustrative view of an induction heating device according to still another embodiment of the present invention.

In this embodiment, an inductor coil 6 having an angular cross-section is formed, and a first surface 6a and a second surface on the radially outer side of the inductor coil 6 are formed.
The inductor coil 6 is wound around the outer periphery of the inner cylinder 1, with the thickness of the inductor coil 6 with respect to the surface 6b being selected to be the length l of half the wavelength of sound as described above.

Although an induction coil having an L-shaped cross section has been described here, the coil cross section may have a shape having a step in the outer diameter direction, such as a T-shape or a U-shape.

As described above, according to the present invention, the outer circumferential surface of the inductor coil along the direction of the inner cylinder is alternately made into a concave and convex shape, and the distance between the concave and convex surfaces is set to be half the wavelength of the sound being generated. This allows the sounds generated from the uneven surface to cancel each other out, reducing noise.

[Brief explanation of drawings]

FIG. 1 is an illustrative view showing an example of a conventional induction heating device. FIG. 2 is an illustrative view of an induction heating device according to an embodiment of the present invention. 3 to 5 are illustrative views of an induction heating device according to another embodiment of the present invention. In the figure, 1 is the inner cylinder, 2 is the object to be heated, 3,4°5.6
indicates an inductor coil.

Claims (1)

[Scope of Claims] 1. Two types of inductor coils are alternately wound around the outer periphery of an inner cylinder made of a heat-resistant material so that the diameters in the outer circumferential direction are different, and the two types of induction An induction heating device characterized in that the diameter difference in the outer circumferential direction of the child coil is selected to be half the wavelength of the sound wave generated from the inductor coil. 2. The two types of inductor coils are formed to have the same thickness in the outer circumferential direction, and on the outer circumferential surface of the inner cylinder, differences in diameter in the outer circumferential direction are formed alternately along the part direction, and 2. The induction heating device according to claim 1, wherein the two types of inductor coils have different diameters in the outer circumferential direction by winding the inductor coil around the outer periphery of a cylinder. 3. The inner cylinder is formed to have the same outer circumferential diameter, and the two types of inductor coils are formed to have different outer diameters corresponding to the difference in diameter in the outer circumferential direction. An induction heating device according to claim 1. 4. An inner cylinder made of a heat-resistant material, a button, and an inductor coil wound around the outer periphery of the inner cylinder, the inductor coil having a cross section having a step in the outer diameter direction; An induction heating device characterized in that the difference in the outer diameter direction between the two outer surfaces due to the step is selected to be half the wavelength of a sound wave generated from an inductor coil.