JPS6157677B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an induction heating roller, and more specifically, the present invention relates to an induction heating roller, and more specifically, the outer periphery of a plurality of magnetic cylinders having a required wall thickness is closely attached to the inner periphery of the roller, and the gaps between the plurality of magnetic cylinders are closed. Both sides of the outer periphery of multiple copper rings with the required thickness are restrained and tightened, and the secondary short-circuit current of one turn circulating in the inner circumferential direction of the roller and inside the copper rings is controlled.
The present invention relates to an induction heating roller that has good surface temperature distribution and power factor.

An induction heating roller is a rotating roller with a guiding wire built into it as a magnetic flux generation mechanism. When an AC voltage is applied to this guiding wire, an alternating magnetic flux is generated from the guiding wire along the axis of the roller. is generated,
Since the rollers are located concentrically with respect to the guide wheel,
The roller forms a secondary short circuit of one turn along the circumferential direction interlinking with the alternating magnetic flux to the guide wire ring as the primary circuit. The roller is usually made of a ferromagnetic metal such as carbon steel, and a short circuit current is generated in the circumferential direction within the thickness of the roller as a secondary short circuit, and the entire cylindrical part of the roller becomes a heat source and generates heat. . The amount of heat generated by the roller is due to the electromagnetic induction effect based on transformer theory due to the electrical energy supplied to the primary induction wire, and as long as the material and wall thickness of the cylindrical part of the roller are uniform, the induced current will be distributed evenly. is formed, and the roller exhibits the heat-uniforming effect unique to electromagnetic induction heating. However, the heat load applied to the roller surface by the product to be processed results in continuous or semi-continuous localized heat dissipation, making the temperature of the roller non-uniform in that area. The temperature distribution in the circumferential direction of the roller is gradually leveled out as the rotation progresses even if a part of it is absorbed by the heat load, but the temperature distribution in the axial direction is such that there is a temperature difference between areas with heat load and areas without heat load. becomes increasingly pronounced, creating an unavoidable tendency for temperature gradients to develop across both zones. This is based on the fact that the difference in the amount of heat dissipated between the two areas cannot be compensated for by thermal exchange within the roller wall thickness, resulting in a temperature difference depending on the specific thermal resistance of the material used for the roller. .

In order to eliminate the above-mentioned drawbacks, the induction heating roller of the present invention has a plurality of magnetic cylinders having a predetermined wall thickness attached to the inner circumference of the roller, and the outer circumferences of the plurality of magnetic cylinders having a predetermined thickness are closely attached to each other, and a predetermined thickness and a predetermined thickness are formed in the gaps between the plurality of magnetic cylinders. Both sides of the outer circumference of the copper ring are restrained and tightened, and the secondary short-circuit current of one turn circulating in the inner circumferential direction of the roller and inside the copper ring is controlled to improve the surface temperature distribution and power factor of the roller. It is something.

In FIG. 1 showing a partial cross-sectional plan view of an embodiment of the induction heating roller of the present invention, a single-axis roller 1 made of a magnetic material is supported so as to be rotatable around a center line 10. , the left end of the roller 1 in the figure is closed, and the right end is open. Inside the roller 1, an annular stratified core leg or wound core leg 6 has one end fixed to a yoke 2 fixed to the outside in a perpendicular direction, and a winding 7 is wound around the outer periphery of the core leg 6. , this winding 7 is the primary guide ring 8
form. Magnetic flux φ generated by the primary guide wire 8
The direction is perpendicular to the center line 10 and is configured to interlink with the roller 1.

Although it is possible to improve the surface temperature distribution of the roller by increasing or decreasing the wall thickness of the plurality of magnetic cylinders on the inner circumference of the roller 1, in the present invention, the plurality of magnetic cylinders 3, 3', 3'', 3 have the same wall thickness.Also, if both sides of the outer periphery of the copper ring with the required thickness are tightened in the gaps 4, 4', 4'', and 4 between the plurality of magnetic cylinders 3, 3', 3'', 3. Based on the energization of the primary induction wire 8, the secondary short-circuit current IL ₂ of one turn circulating in the inner circumferential direction of the roller 1 increases, thereby improving the temperature distribution and power factor on the surface of the roller 1. becomes.
In other words, due to the difference in thermal expansion coefficient between the magnetic cylinder 3, 3', 3'', 3 and the copper ring 5, 5', 5'', 5, the expansion and contraction rate of the copper ring 5, 5', 5'', 5 is the same as that of the copper ring. The magnetic cylinder and the copper ring are always in close contact with each other to achieve the effect of heat transfer between them. ,3″,3 and copper ring 5,
The secondary short-circuit current circulating through the rollers 5', 5'', and 5 has a synergistic effect with the secondary short-circuit current of one turn, thereby improving the surface temperature distribution of the roller 1 and the power factor of the roller. FIG. 2 shows the temperature distribution of an embodiment of the induction heating roller of the present invention, where the horizontal axis shows the axial length of the roller, and the vertical axis shows the surface temperature T of the roller.

Also, the diameter of this roller is 176 mm, the length is 185 mm, the rotation speed is 5000 rpm, and the wall thickness of the magnetic cylinder is the same.
4.5mm, the number of copper rings installed is 4, and their total thickness is 1.4, 0.7, 0.7, 2.2mm.

In this case, increasing the wall thickness of the magnetic cylinders 3, 3', 3'', 3 and the total thickness of the copper rings 5, 5', 5'', 5 will improve the roller surface temperature distribution and the roller power factor. It has been proven that That is, the surface temperature of the roller varied from 183.2° to 184.0°, and the power factor of the roller in this case was 82%. The applied voltage in this case was 180 volts and a single-phase primary current of 20.4 amperes.

Figure 3 is a vector diagram of the induction heating roller of the present invention, in which both sides of the outer periphery of copper rings 5, 5', 5'', 5 with a predetermined thickness are restrained and tightened in the gaps between magnetic cylinders 3, 3', 3'', 3. . In this case, if the wall thickness of the magnetic cylinder and the total thickness of the copper ring are set to appropriate values, the excitation current I ₀ will not change, but the secondary short circuit current IL ₂ of one turn will become IL _{2 '} , and the primary current IL ₁ will become IL ₁ The input current I ₁ to the primary induction wire, which is the vector sum with the exciting current I ₀ , becomes I ₁ ′, which improves the power factor of the roller to ′. .

[Brief explanation of the drawing]

FIG. 1 is a partially sectional plan view showing an embodiment of the induction heating roller of the present invention. FIG. 2 is a chart showing the temperature distribution of the roller in the embodiment shown in FIG. FIG. 3 is an explanatory diagram showing that the power factor is improved by increasing the secondary short circuit current. In the figure, 1... roller, 2... yoke,
3, 3', 3'', 3...magnetic cylinder, 4, 4',
4'', 4... air gap, 5, 5', 5'', 5... copper ring, 6... stratified iron core leg or wound iron core leg, 7...
...Winding, 8...Primary guide wire ring.

Claims (1)

[Claims] 1. A fixed yoke, a roller supported so as to be able to rotate around the center line of the yoke, and a roller fixed to the yoke around the center line in a direction perpendicular to the yoke. The core leg consists of a core leg, and a winding wound around the outer circumference of the core leg, and this winding forms a primary guide ring, and the magnetic flux generated from this primary guide ring is linked to the roller. 1. An induction heating roller configured as follows, characterized in that a plurality of magnetic cylinders having a predetermined wall thickness are closely attached to the inner periphery of the roller. 2. The induction heating roller according to claim 1, in which the outer periphery of a plurality of magnetic cylinders is closely attached to the inner periphery of the roller, and both outer periphery surfaces of a copper ring of a required thickness are restrained and tightened in the gaps between the plurality of magnetic cylinders. An induction heating roller characterized by: