JP4080122B2 - Induction heating roller device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an induction heating roller device, and more particularly to an induction heating roller device configured by inserting support rods that support an induction heating mechanism into journals provided at both ends of a roller body.
[0002]
[Prior art]
In this type of device, a journal is integrally provided at both ends of a roller body having a hollow interior, the journal is rotatably supported on a machine base via a bearing, and an induction coil is provided inside the roller body. An induction heat generating mechanism with a support rod is arranged and supported by a support rod, and the support rod is supported by an internal bearing with respect to the journal so that the induction heat generation mechanism is suspended in the interior of the roller body. Is known.
[0003]
FIG. 5 shows the structure, 1 is a roller body having a hollow inside, and is integrally provided with hollow journals 2 at both ends thereof, and the journal 2 is fixed by a bearing 3 on the outside thereof. 4 is rotatably supported. The roller body 1 is rotated by rotating the journal 2 with an appropriate drive source (for example, a motor).
[0004]
Inside the roller body 1, an induction heating mechanism 7 including an iron core 5 and an induction coil 6 wound around the iron core 5 is arranged, and both ends thereof are supported by support rods 8. The support rod 8 is supported by an internal bearing 9 such as a rolling bearing with respect to the journal 2, whereby the induction heating mechanism 7 is supported suspended in the roller body 1. Reference numeral 10 denotes a sleeve provided between the internal bearing 9 and the support rod 8 as required. Reference numeral 11 denotes a lead wire of the induction coil 6 which is led out from the end through the inside of the support rod 8 and is externally excited. It is connected to an AC power source.
[0005]
In the above configuration, when an AC power supply is applied to the induction coil 6 and excited, a current is induced in the peripheral wall of the roller body 1, and the roller body 1 generates heat by induction. By the way, in such a configuration, the internal bearing 9 was damaged in a short period of time, and the life thereof was remarkably shortened. After extensive examination of the cause, it was found that it was caused by the following causes.
[0006]
That is, the induction coil 6 may be divided into three parts, and each of them may be star-connected to a three-phase AC power source. However, according to such a connection configuration, both sides of the induction heating mechanism 7 (in the axial direction of the roller body 1). An alternating potential is generated on both sides), and an alternating potential having a polarity opposite to that of the alternating potential is also induced on both sides of the roller body 1 constituting a secondary circuit for the induction heating mechanism 7 . all right. In the figure, symbols + and − in circles indicate the polarity of the induced potential. The same applies when the induction coil is delta-connected.
[0007]
For example there is when the polarity of the alternating voltage, as shown in figure support rod 8 on each side of the induction heating mechanism 7 is generated, whereas the journal 2 in the same time on both sides of the roller body 1 with respect to this, An alternating potential having a polarity opposite to the potential induced in the support rod 8 is induced.
[0008]
The generation of such an alternating potential is considered to be due to the following reason. That is, the induction coil 6 is divided into three parts as described above, and this is arranged along the axial direction of the roller body 1 as shown in the figure, and the divided induction coils 6 are arranged for each phase of the three-phase AC power source. In the case of star connection, there was no problem when the power factors of the divided induction coils were all equally balanced.
[0009]
However, if there is an imbalance in the power factor of the induction coil, the potential at the neutral point of the star connection changes, so that an alternating potential (floating potential) is generated on both sides of the induction heating mechanism 7, and the roller body 1 Since a secondary circuit is configured with respect to the induction heating mechanism 7, it is considered that an alternating potential having a polarity opposite to the potential generated on both sides of the induction heating mechanism 7 is also generated on both sides of the roller body 1.
[0010]
Such an alternating potential does not generate a large amount of power, but a current based on this potential flows as indicated by the arrow in the figure via the journal 2, the roller body 1, and the support rod 8, and this current is Flows through the internal bearing 9. When a rolling bearing is used as the internal bearing 9, the lubricating oil or the lubricating grease film between the surface of the ball and the rolling surface may be interrupted by the rolling of the ball constituting the rolling bearing. Therefore, energization and disconnection are repeated between the surface of the ball and the rolling surface, and therefore sparks are generated.
[0011]
When such a spark is generated, the lubricating oil or lubricating grease deteriorates, and the inner bearing 9 becomes a rolling surface and the surface of the ball (or roller) is damaged and roughened. When the surface becomes rough, rolling as a bearing is hindered. In addition, when the rolling resistance is deteriorated in this way, the rolling resistance is increased and heat is generated. As a result, it has been found that the life of the internal bearing 9 is shortened.
[0012]
[Problems to be solved by the invention]
An object of the present invention is to prevent occurrence of damage to an internal bearing due to a floating potential induced in a roller body and a support rod.
[0013]
[Means for Solving the Problems]
The present invention provides an induction heat generation comprising a journal integrally provided at both ends of a roller body having a hollow inside, an induction coil disposed inside the roller body and excited by a three-phase AC power source. In an induction heating roller device in which a support rod for supporting a mechanism is inserted into the journal and the support rod is supported by the internal bearing with respect to the journal, the internal bearing interposed between the support rod and the journal is connected to the journal. It is characterized by providing an insulating mechanism for preventing current flow. Also, a short-circuit conductive brush is provided between the support rod and the journal so as to short-circuit the internal bearing.
[0014]
Since the internal bearing that supports the support rod with respect to the roller body is electrically insulated from the support rod or the journal, current due to floating potential induced in the roller body does not flow to the internal bearing. Therefore, no spark is generated in the bearing, and therefore damage to the bearing is avoided.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIG. Note that portions denoted by the same reference numerals as those in FIG. 5 indicate the same or corresponding portions. FIG. 1 shows a detailed configuration when a sleeve 10 is used. The sleeve 10 is fixed to the support rod 8 by a retaining ring 15, and the internal bearing 9 composed of a rolling bearing is secured to the sleeve 10 by a retaining ring 16. It is fixed to the journal 2 by a ring 17.
[0017]
The example in the figure shows a case where the inner bearing 9 and the support rod 8 are insulated, and for this purpose, insulating coatings 17 and 18 made of, for example, ceramic coating are formed on the inner surface of the sleeve 10 and the outer surface facing the inner bearing 9. (See FIG. 2). Insulating rings 19 and 20 are installed on the end faces of the sleeve 10, and insulating rings 21 and 22 are installed at positions facing the end faces of the internal bearing 9.
[0018]
Thus, when the sleeve 10 and the internal bearing 9 are attached between the support rod 8 and the journal 2, the insulating coatings 17 and 18 and the insulating rings 19 to 22 are provided between the internal bearing 9 and the support rod. Therefore, the flow of electric current due to the floating potential to the internal bearing 9 is prevented.
[0019]
FIG. 3 shows another embodiment of the present invention. This example shows a case where the sleeve 10 is not used, and an insulating coating 23 is formed on the inner surface of the inner bearing 9 facing the outer surface of the support rod 8. A retaining ring 24 for fixing the internal bearing 9 to the support rod 8 is provided. Insulating rings 25 and 26 are provided on both end faces of the internal bearing 9.
[0020]
When the internal bearing 9 is mounted between the support rod 8 and the journal 2 in this way, the internal bearing 9 and the support rod 8 are electrically insulated by the insulating coating 23 and the insulating rings 25 and 26. As a result, the flow of current due to the floating potential to the internal bearing 9 is blocked. 1 and 3 is configured to insulate between the internal bearing 9 and the support rod 8, but may be configured to insulate between the internal bearing 9 and the journal 2 instead. .
[0021]
FIG. 4 shows yet another embodiment of the present invention. In this configuration, the internal bearing 9 is short-circuited so that a current due to the floating potential is bypassed by the conductive brush. A conductive brush holder 28 having a conductive brush 27 is attached to the journal 2 side, and the tip of the conductive brush 27 Is in contact with the outer peripheral surface of the support rod 8. According to this, the current due to the floating potential flows between the journal 2 and the support rod 8 via the conductive brush 27 and does not flow to the internal bearing 9.
[0022]
Each of the above embodiments is an example in which a rolling bearing using a ball that is likely to generate sparks is used as the internal bearing 9, but a bearing that does not use a ball and lubricating oil, that is, a sliding bearing is used as the internal bearing. Even in this case, damage to the bearing due to the occurrence of sparks can be reliably avoided.
[0024]
【The invention's effect】
As described above, according to the present invention, in the configuration in which the support rod that supports the induction heating mechanism disposed inside the roller body is supported by the journal that is connected to the roller body via the internal bearing, the support rod, the journal, This prevents the flow of current due to the floating potential to the internal bearing that is interposed between them. This has the effect of enabling a longer life.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional view showing an embodiment of the present invention.
FIG. 2 is a cross-sectional view of the sleeve in FIG.
FIG. 3 is a partial cross-sectional view showing another embodiment of the present invention.
FIG. 4 is a partial sectional view showing still another embodiment of the present invention.
FIG. 5 is a cross-sectional view of an induction heating roller device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Roller body 2 Journal 7 Induction heating mechanism 8 Support rod 9 Internal bearing 10 Sleeve 17 Insulating film 18 Insulating film 19-22 Insulating ring 23 Insulating film 25-26 Insulating ring 27 Conductive brush

Claims (2)

Journals are integrally connected to both ends of a roller body having a hollow inside, and are arranged inside the roller body to support an induction heating mechanism having an induction coil excited by a three-phase AC power source. The support rod is inserted into the journal, the internal bearing is made conductive, and an insulating mechanism is provided between the support rod and the conductive bearing, or between the journal and the conductive bearing, and the roller An induction heating roller device characterized in that a current flowing through the support rod based on a potential difference generated between both sides of the main body is interrupted by the insulating mechanism . Journals are integrally connected to both ends of a roller body having a hollow inside, and are arranged inside the roller body to support an induction heating mechanism having an induction coil excited by a three-phase AC power source. In an induction heating roller device in which a support rod is inserted into the journal and the support rod is supported by an internal bearing with respect to the journal, a conductive brush is provided between the support rod and the journal , An induction heating roller device , wherein a current flowing through the support rod based on a potential difference generated between both sides is short-circuited by the conductive brush .

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