JPH079355Y2 - Induction heating roller device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to an induction heating roller device.

(Prior Art) It is widely known to use this type of induction heating roller device in heating a sheet material such as plastic, paper, cloth, non-woven fabric, metal foil, or a web material.

Generally, the surface temperature of the roll used in this device is 100
The purpose can be sufficiently achieved at about 300 ° C.

However, recently, due to the increasing demand for engineering plastics and other highly heat-resistant materials, there is an increasing tendency for the surface temperature of rolls to rise to 300 ° C or higher, and in some cases, temperatures above 400 ° C are required. Sometimes.

The most problematic aspect of these requirements is the insulation performance of the induction coil, which constitutes the induction heating mechanism provided inside the roll, against high temperatures.

As a countermeasure, as disclosed in Japanese Utility Model Publication No. 57-52874, a spacer made of a heat-resistant electric insulating material is inserted between the electric wires and between the iron core and the induction coil to ensure sufficient electric It seeks to improve insulation and thermal efficiency.

Alternatively, as shown in Japanese Patent Publication No. 57-5356,
A ceramic coating is applied to the electric wire, or an alumite coating is applied to the aluminum electric wire, and the electric wire is used to form an induction coil.

(Problems to be solved by the invention) However, when the spacer is used as in the former case, not only heat resistance but also mechanical strength is required as the spacer. If the mechanical strength is not sufficient, it may be damaged by vibration or other external force, so that part or all of it may fall off, which makes it impossible to maintain the electric wire.

Since mechanical strength is required in this way, a spacer that is too thin cannot be used as this type of spacer.
The space factor of the electric wire in the induction coil will decrease. This is an extremely disadvantageous design condition especially in a small roll device.

That is, the amount of heat (capacity) required for the roll to be generated is determined by the usage conditions of the roll, and the required cross-sectional area of the wire is determined from the value of the current flowing in the induction coil. Also, since the required number of windings of the electric wire is determined from the electric resistance value in the winding direction of the roll body and the capacity, when winding the electric wire on the outer peripheral surface of the iron core having a length substantially equal to the body length of the roll, The thickness of the spacer, the thickness of the electric wire and the height must be determined so that the required number of windings can be completed.

However, a small roll tends to have a large number of windings, and in order to allow the spacer and the electric wire to coexist there, it is necessary to wind an extremely thin electric wire in the edgewise direction. That is, since the height is high instead of the thin one, the winding work becomes extremely difficult.

In addition, this limits the outer diameter of the iron core, which tends to reduce the iron core cross-sectional area and increase the magnetic flux density.
As a result, the iron core portion is overheated or magnetic saturation occurs.

In addition, like the latter, when the ceramic coating is applied to the electric wire or the aluminum wire is anodized, and the induction coil is formed by using the electric wire, it goes without saying that the ceramic is It is an oxide obtained by firing or chemical reaction, has extremely high hardness and has brittle properties, and has a very small coefficient of thermal expansion as compared with metals.

On the other hand, as the characteristics of ceramics, the insulation performance is good, and not only a thin film can obtain sufficient dielectric strength, but its characteristics do not extremely decrease even at 800 ° C or higher. For the above reasons, the electric wire described above is extremely useful for an induction coil of this type of induction heating roller device.

However, since the ceramic is extremely hard and brittle as described above, there is a high possibility that the coating film will be damaged by a mechanical external force during the winding operation on the iron core. In addition, it is necessary to take out the process of winding the wire wound around the wire drum, which is delivered from the wire manufacturer, and then winding it around the iron core. It cannot be repeated. Therefore, the generation of minute cracks in the ceramic layer cannot be avoided.

This tendency becomes remarkable because the bending radius of the electric wire becomes smaller as the outer diameter of the iron core becomes smaller.

On the other hand, raising the temperature of the roll also causes the internal induction coil to rise in temperature equal to or higher than that of the roll. Therefore, the induction coil expands due to heat cycle,
The contraction will be repeated. Therefore, due to the difference in the coefficient of thermal expansion from the conductor, it cannot be ignored as a cause of the generation of the microcracks.

Any damage or minute cracks in these ceramic coatings cause a dielectric breakdown accident between lines or ground.

Further, if the thickness of the ceramic film is increased in order to prevent this, as will be understood from the above description, it is obvious that the effect is completely opposite, and in reality, there is no countermeasure.

It is an object of the present invention to prevent the insulator from falling off, breaking, or producing minute cracks while sufficiently increasing the space factor of the electric wire of the induction coil.

(Means for Solving the Problem) The present invention configures an induction coil by an electric wire which is provided with a heat-resistant insulating coating and which is obtained by impregnating the insulating coating with an unsintered ceramic mainly composed of an inorganic polymer. It is characterized by having done.

(Operation) By impregnating the insulating coating with unfired ceramic, the insulation of the electric wire can be configured without losing flexibility. Therefore, when winding the coil,
There is no damage or crack in the ceramic unlike the ceramic-coated wire.

Moreover, it is not necessary to use an insulating spacer, and the space factor can be increased accordingly. Moreover, since there is no need to wind such an insulating spacer at the same time, the work becomes easy, and there is no scandal accident such as dropping or damage of these.

(Embodiment) An embodiment of the present invention will be described with reference to the drawings. Reference numeral 1 is a rotary shaft, and a cylindrical roller 2 with a lid, one end of which is open, is attached to the tip thereof by a bolt 3 at the center of the lid.

4 is a non-rotating flange attached to the machine base so as to close the open surface of the roller 2, 5 is an iron core mounted on the outer surface of the horizontal portion of the flange 4, and an insulating layer 6 is provided outside the iron core. The induction coil 7 is wound around.

A jacket chamber 8 is formed on the peripheral wall of the roller 2,
A gas-liquid two-phase heat medium is enclosed in the inside.

For the induction coil 7, an electric wire 9 is wound with a heat-resistant and well-impregnated thread or tape such as glass thread, glass tape, or ceramic tape, and the insulation coating 10 is applied.

The insulating coating 10 is impregnated with a liquid unfired ceramic (for example, alumina ceramic) mainly composed of an inorganic polymer. In this case, the insulation coating 10 may be previously impregnated with the above-mentioned unfired ceramic and dried before being wound on the electric wire 9, or the insulation coating 10 may be wound on the electric wire 9 and then the You may make it immerse in the liquid of the said unfired ceramic, impregnate, and make it dry.

In any case, the insulating coating 10 itself has flexibility, and the impregnated unfired ceramic is also unfired, so the flexibility of the insulating coating 10 is not lost.

For the purpose of impregnating such an unfired ceramic, the heat-resistant insulating coating as described above has extremely high porosity (void), and good characteristics such as insulation resistance and breakdown voltage cannot be obtained. By impregnating the ceramic as described above, the insulating performance of the insulating coating can be improved by the insulating performance of the ceramic itself. It also effectively acts to improve the mechanical strength of the insulating coating.

By using the electric wire wound with the insulating coating impregnated with the unfired ceramic as described above, the insulating spacer is unnecessary, which increases the space factor and simplifies the work. Accidents of falling out and damage disappear.

Further, unlike the case where an electric wire coated with a ceramic is used, the ceramic layer is not damaged or cracked, and the core having a small diameter can be dealt with.

Although the insulating coating is wrapped around the wire, it is not completely integrated, but is covered with a minute gap, and the unfired ceramic is completely fired. Since the temperature is, for example, 450 to 500 ° C., if the temperature is lower than that, it will not be a completely cured layer,
It remains flexible. For these reasons, the problem of thermal expansion difference caused by heat cycle can be solved at the same time.

As the electric wire, an aluminum electric wire, a copper electric wire, a silver-containing electric wire or the like can be used, but in the case of a copper electric wire, it is preferable to apply an oxidation resistant coating as a measure against oxidation at high temperature.

(Effects of the Invention) As described in detail above, according to the present invention, the space factor of the electric wire of the induction coil can be sufficiently increased, and the dropout, breakage, or crack of the insulator can be surely avoided. There is an effect that can be.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, and is a front view with an upper half section taken as a section, and FIG. 2 is a partially enlarged sectional view of the induction coil shown in FIG. 2 ... Roller, 5 ... Iron core, 7 ... Induction coil, 8 ...
Jacket room, 9 ... electric wire, 10 ... insulation coating,

Claims (1)

[Scope of utility model registration request] 1. A jacket chamber in which a gas-liquid two-phase heat medium is enclosed is provided in a peripheral wall of a rotatably supported hollow roller, and an iron core and an iron core are wound inside the roller. In an induction heating roller device provided with an induction heating mechanism configured by an induction coil, an insulating coating is provided by winding a heat resistant thread or tape such as glass thread, glass tape, or ceramic tape. An induction heating roller device in which the induction coil is formed by an electric wire in which the insulating coating is impregnated with a liquid unfired ceramic mainly composed of an inorganic polymer.