JP4391867B2 - Induction heating device - Google Patents

Description

  The present invention relates to an induction heating device for heating a rolled material or other heated material in a hot rolling line, and in particular, a conveying table roller for the heated material is provided before and after the induction heating device main body, and induction is performed. The present invention relates to an induction heating apparatus having a structure that reduces an arc generated between the transport table roller and the heated material by an induced current of the heated material heated by the heating apparatus.

  In a hot rolling line, a rolled material heated to a temperature capable of being rolled by a heating furnace is roughly rolled in a roughing mill and formed into a state called a rough bar. Products with plate pressure and width are obtained. In this case, a full-width heating device called a bar heater or an end heating device called an edge heater is used for the rolling material in a rough bar state in order to prevent a temperature drop or to equalize the temperature of each part. The

  Various heating devices for the rolled material and other heated materials have been proposed, and one of them is a solenoid induction heating device that performs full width heating of the heated material. This solenoid induction heating apparatus is a system in which an eddy current is generated in a material to be heated by a magnetic field of an induction heating coil disposed above and below the entire width of the material to be conveyed, and heating is performed using Joule heat.

  The magnitude of this heating current is proportional to the amount of magnetic flux, but since the magnetic flux density is constant inside the material to be heated, if the width of the material to be heated is wide, the magnetic flux increases as the cross-sectional area increases. In proportion, the heating current also increases. Therefore, in a large induction heating apparatus that heats the entire width of the material to be heated such that the width reaches about 4-5 m, the heating current becomes large, and the width of the heating material increases along the surface of the material to be heated. It flows so as to circulate throughout the entire area.

  By the way, in order to supply a material to be heated to such an induction heating device, a conveyance table roller is provided before and after the induction heating device, and the material to be heated is conveyed while being supported from below. However, in such an induction heating apparatus, the heating current flowing over the entire width direction of the material to be heated during induction heating wraps around from the lower surface of the material to be heated B toward the transport table roller R as shown in FIG. A phenomenon occurs in which an arc is generated between the contact portion between the heating material and the transport table roller, particularly between both ends of the heated material and the surface of the transport table roller.

  The occurrence of such an arc causes damage to the surface of the material to be heated, which is the object to be processed, and has the disadvantage of causing a reduction in product quality. Also, the arc may damage the surface of the transport table roller, and the damaged transport table roller may come into contact with the material to be heated, so that the material to be heated may be damaged by the scratch of the roller even when the arc is not generated. .

In order to solve such a problem, as in Patent Document 1 and Patent Document 2, proposals have been made to prevent the occurrence of an arc of the material to be heated and the conveying table roller.
Japanese Utility Model Publication No. 4-134203 JP-A-9-38712

  The inventions described in Patent Document 1 and Patent Document 2 both relate to an end heating device for a material to be heated. As shown in FIG. 5, an induction heating device (edge heater) H for edge heating is used. This prevents the occurrence of a spark between the heated material B and the transport table roller R due to the induced current generated when the end portion of the heated material B is heated.

  In order to prevent sparks in such an edge heater, it is sufficient not to contact only the edge portion where the heating induction current is generated with the material to be heated. For example, as in the invention of Patent Document 2, a transfer table is used. A step portion is provided only in a range corresponding to the edge portion of the heated material in the roller so as to avoid contact with the heated material.

  However, as in the present invention, in an apparatus that performs induction heating over the entire width of the material to be heated, as shown in FIG. Therefore, even if the configuration is such that only the edge portion of the transport table roller is stepped and does not come into contact with the material to be heated, the wraparound of the heating current cannot be prevented.

  As described above, in the conventional full width induction heating apparatus, since the generation of the arc cannot be prevented even if the above-described technique is used, the conveyance table roller is induction heated with an emphasis on preventing the material to be heated from being damaged by the arc. There has been a trade-off between placing it at a location away from the entrance / exit of the apparatus, or placing the transport table roller near the entrance / exit of the induction heating apparatus with emphasis on transport stability.

  In particular, in a heating induction device that heats a material to be heated at a high temperature of 700 ° C. or higher, the material to be heated also becomes a non-magnetic material, and the magnetic flux density rapidly decreases as the distance from the outlet of the induction heating device decreases. In the full width induction heating apparatus for the purpose of heat treatment for improving the characteristics of the material, the heating temperature is as low as about 700 ° C. or less, and the material to be heated also maintains the properties as a magnetic substance, and therefore, it is added thereto The magnetic flux becomes large, and even when it is away from the outlet of the heating device, the attenuation rate is small as compared with the high temperature heating.

  For this reason, in an induction heating apparatus that targets a low-temperature heating area that retains the properties of this kind of magnetic material, if the conveyance table roller is provided near the entrance / exit of the induction heating apparatus, Sparks were generated between the heated materials, and it was inevitable that the surface of the heated material was damaged by the sparks.

Furthermore, in order to solve these problems, as shown in Patent Document 2, it has been proposed to cover the entire area of the roller with insulating ceramics. However, when such an insulating roller is used, the roller is supported. Insulating ceramics are damaged or peeled off due to the impact of the load of the material to be heated or the vibration during transportation, resulting in a problem that the insulating property is lowered in a short period of time.

  As described above, according to the prior art, in a wide heated table material transport table roller made of thick plate material, the roller surface is insulated and an anti-arcing roller having impact resistance and long insulation life is supplied. That was difficult.

  The present invention has been proposed in order to solve the problems of the prior art as described above, and the conveying table roller and the material before and after the induction heating device are generated by the induction current of the material heated by the induction heating device. It is an object of the present invention to provide an induction heating apparatus having a structure for reducing arcs generated during heating.

In order to achieve the above object, the present invention provides an induction heating apparatus comprising an induction heating apparatus main body that heats a material to be heated over its entire width, and a conveyance table roller apparatus disposed before and after the induction heating apparatus main body. The roller device includes a plurality of independent transport table roller bodies arranged along the width direction of the material to be heated, a bearing that supports each transport table roller body, and a drive motor that rotationally drives each transport table roller body. A bearing supporting each of the transport table roller bodies is insulated from the ground, and the transport table roller body and an output shaft of a drive motor thereof are connected via an insulating joint.
It is also one of the embodiments of the present invention that the induction heating device main body heats the material to be heated at the temperature of the magnetic region.

  In the present invention, the respective transport table roller bodies constituting the transport table roller device are arranged independently in the width direction of the material to be heated, and the respective transport table roller bodies are connected by an insulating joint or not at all. Since they are arranged at separate positions, a current path that flows from one end of the material to be heated to the other end of the material to be heated via each conveyance table roller body is not formed. At the same time, since each transport table roller body is also insulated from the bearings and the drive motor, insulation of the material to be heated and each transport table roller body is also ensured.

  As a result, the current inside the heated material flows through the shortest path along the surface of the heated material without being shunted to the conveying table roller side, so in the contact portion between the conveying table roller and the heated material, The phenomenon of arcing is effectively prevented. Therefore, the possibility that the surface of the heated material and the surface of the table roller are damaged by an arc or the surface of the heated material is damaged by the damaged roller surface is solved.

  Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

1. Configuration of Embodiment As shown in FIG. 2, the basic structure of the induction heating device of the present invention is a conveyance table roller disposed before and after the main body of the induction heating device H that heats the entire width of the material to be heated. The apparatus 1 and a motor 2 for driving the apparatus 1 are configured. The configuration of the transport table roller apparatus 1 is as shown in FIG.

  The transport table roller device 1 and the drive motor 2 are supported on a base 3 fixed to the floor surface. The transport table roller device 1 includes a plurality of (five in the present embodiment) bearings 4 provided on the base 3 at predetermined intervals, and a plurality of transport table roller bodies 5 supported by these bearings 4. And. Further, an insulating member 6 is provided between each bearing 4 and its base 3, and the transport table roller body 5 and the left and right bearings 4 are insulated from the base 3.

Each transport table roller main body 5 is arranged linearly along the width direction of the material to be heated, and is connected to each other via an insulating joint 7. Is connected to the output shaft 8 of the drive motor 2. An insulating joint 7 is also provided between the transport table roller body 5 and the output shaft 8 of the motor 2 so that the transport table roller body 5 and the motor 2 are insulated. In this case, as the insulating joint 7, a rubber joint generally called a tire coupling, or an insulating material sandwiched between metal couplings is used.

  Since this insulating joint 7 is disposed in the vicinity of the heated material to be heated, it is desirable to provide the cooling device 9 in consideration of its heat resistance. The cooling device 9 may be one that constantly sprays cooling water constantly while the transport table roller main body 5 is driven, or a coil in which a heat shielding plate 10 is provided on the outer periphery of the insulating joint 7 and the cooling water circulates in the inside. 11 can be used.

2. Effects of Embodiment The transport table roller apparatus 1 in the present embodiment having such a configuration provides a plurality of transport table roller bodies 5 along the width direction of the material to be heated to support the material to be heated, Moreover, since the conveyance table roller main bodies 5 are insulated by insulating joints, the current inside the heated material flows along the surface of the heated material without being diverted to the conveyance table roller main body 5 side. As a result, the phenomenon of arc generation at the contact portion between the transport table roller body 5 and the material to be heated is effectively reduced.

  In addition, since the insulating member 6 and the insulating joint 7 are provided between the bearing 4 that supports the conveying table roller body 5 and the output shaft 8 of the drive motor 2, the conveying table roller body 5 is insulated from the ground. As a result, the current inside the heated material is not grounded from the heated material via the transport table roller main body 5 or its drive motor 2, and sufficient insulation is secured in this respect.

  Furthermore, if the cooling device 9 is provided at the joint portion with the conveying table roller body 5 and the drive motor 2 as in the above embodiment, it is sufficient even when a rubber tire coupling or the like is used. Since the heat resistance can be ensured, the conveyance table roller device 1 can be arranged in the vicinity of the induction heating device, the interval between the conveyance table roller devices 1 provided at the entrance / exit portion of the induction heating device can be reduced, and the conveyance The vibration of the material to be heated at the time can be effectively prevented.

3. Other Embodiments FIG. 3 is a front view showing another embodiment of the present invention. This embodiment is characterized in that a plurality of transport table roller bodies 5 arranged separately along the width direction of the material to be heated are each driven by an independent drive motor 2.

  Also in this embodiment, each transport table roller main body 5 is arranged at a distance sufficient to ensure insulation, and each transport table roller main body 5 and the output shaft 8 of the drive motor 2 are insulated joints. 7 and an insulating member 6 is also provided between the bearing 4 and the base 3 to ensure insulation.

  Also in the embodiment of FIG. 3 having such a configuration, the transport table roller body arranged in the width direction of the material to be heated is divided, and the current flowing in the width direction of the material to be heated is divided into the transport table roller body. The shunting to the side is prevented. As a result, the generation of an arc at the contact portion between the heated material and the transport table roller main body is reduced, and the heated material and the roller are prevented from being damaged.

The front view which shows embodiment of the stepped roller used for the induction heating apparatus of this invention. The side view which shows the basic composition of the induction heating apparatus of this invention. The front view which shows other embodiment of the induction heating apparatus of this invention. Sectional drawing which shows the state of the wraparound of the electric current between the to-be-heated material and a stepped roller in the stepped roller part of an induction heating apparatus. The top view which shows the state of the heating induction current produced in the conventional edge heater.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Conveying table roller apparatus 2 ... Drive motor 3 ... Base 4 ... Bearing 5 ... Conveying table roller main body 6 ... Insulating member 7 ... Insulating joint 8 ... Output shaft 9 ... Cooling device 10 ... Shielding plate 11 ... Coil

Claims (6)

In an induction heating apparatus provided with an induction heating apparatus main body that heats the material to be heated over its entire width, and a transport table roller apparatus disposed before and after the induction heating apparatus main body,
The transport table roller device includes a plurality of independent transport table roller bodies arranged along the width direction of the material to be heated, a bearing that supports each transport table roller body, and a drive that rotationally drives each transport table roller body. With a motor,
An induction heating apparatus, wherein a bearing for supporting each of the transport table roller bodies is insulated from the ground .   The induction heating apparatus according to claim 1, wherein the conveyance table roller main body and an output shaft of a drive motor thereof are connected via an insulating joint.   The induction heating apparatus according to claim 1 or 2, wherein the induction heating apparatus main body heats the material to be heated at a temperature of the magnetic region. Two drive motors are arranged at both ends of the material to be heated in the width direction of the plurality of independent transfer table roller bodies,
The induction heating device according to claim 1 or 2, wherein the plurality of transport table roller bodies arranged independently are divided into two groups, and each group is driven by a different drive motor.   4. The induction heating apparatus according to claim 1, 2, or 3, wherein each of the transport table roller bodies arranged independently is driven by a different drive motor.   The induction heating device according to claim 2, wherein the insulating joint is constituted by a rubber tire coupling and includes a cooling device.

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