JP3208516B2 - Induction heating roller device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an induction heating roller device.

[0002]

2. Description of the Related Art An electromagnetic induction heating mechanism provided with an induction coil is installed inside a rotating hollow roller to cause the peripheral wall of the roller to generate Joule heat by an induced current. An induction heating roller device which is provided with a jacket chamber in which a medium is sealed, and is configured to equalize the surface temperature of the roller by vaporizing and condensing the heating medium,
It is already well known.

In such an induction heating roller device,
The induction coil may be excited by a three-phase power supply. For this purpose, three induction coils may be prepared and each of them may be connected between the phases of the three-phase power supply. However, in such a configuration, the distribution of heat generated by each induction coil tends to be the strongest at the central portion along the axial direction of the coil.

FIG. 5 shows an example. FIG. 1 shows the relationship between the position of the roller 1 and the electromagnetic induction heating mechanism 3 having three induction coils 2 in this type of apparatus.
2 shows the relative heat distribution of the sample. 4 is a jacket room. As described above, since the amount of heat generated at the roller portion corresponding to the central portion of the induction coil 2 is the largest, the heat generation distribution along the axial direction of the roller 1 has large irregularities as shown in the figure.

[0005] With such a heat distribution, the difference in thermal expansion (thermal crown) in the radial direction of the roller 1 becomes large, and the nip pressure becomes non-uniform especially in the application of the nip roller. When the jacket chamber 4 is provided, the heat distribution is flattened by the heat equalizing action of the heat medium as compared with the case where the jacket chamber 4 is not provided, but it is still insufficient.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to sufficiently flatten the heat distribution of a roller when an induction coil in an electromagnetic induction heating mechanism for causing a roller to generate heat is excited by a three-phase power supply.

[0007]

According to the present invention, an induction coil is composed of a main coil and an extension coil, and the main coil is divided into multiples of three, and each of the divided coils is divided by a three-phase power supply for the same number. Connected via a rectifier so that a half-wave current of one polarity, positive or negative, flows between each phase, and a three-phase power supply is connected between the intermediate point of each split coil and the end of the extension coil. A rectifier is connected between the phases so that a half-wave current of the other polarity of each phase flows.

[0008]

When the induction coil is connected to the three-phase power supply, half-wave current of one polarity of the three-phase power supply flows through each divided coil, and the roller corresponding to each divided coil generates heat. Next, when the polarity of the three-phase power supply is reversed, a half-wave current of the other polarity flows between the intermediate points of the divided coils and between the intermediate point and the end of the extension coil, and corresponds to the coil portion through which this current flows. The roller generates heat.

As a result, the heat generation region of the roller corresponding to the length of the split coil moves left and right along the axial direction of the roller each time the polarity of the three-phase power supply is reversed. Therefore, even if the split coil is connected between the phases of the three-phase power supply, the roller portion corresponding to the space between the split coils also generates heat. Is flatter than when connected between the phases.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. The configuration in which a jacket chamber 4 in which a gas-liquid two-phase heat medium is sealed is provided inside the peripheral wall of the roller 1 which includes a roller 1 and an electromagnetic induction heating mechanism 3 including an induction coil 2 is the same as the conventional one. is there. Reference numeral 5 denotes an end plate that closes both ends of the roller 1, and 6 denotes a drive shaft integrated with the end plate 5, which is rotatably supported by a machine base 7 via a bearing 8. This is rotationally driven by a required drive source, and the roller 1 is rotated by this rotational drive.

Reference numeral 9 denotes a support rod for supporting the electromagnetic induction heating mechanism 3, which is inserted into the drive shaft 6 and has a bearing 10.
And is supported by the drive shaft 6 via the A plurality of jacket chambers 4 are provided along the circumferential direction of the roller 1, each of which may be independent of each other, or may communicate with each other at an end. These configurations are not particularly different from the conventional induction heating roller device of this type.

According to the present invention, the induction coil 2 comprises a main coil 11 and an extension coil 12 connected in series to the main coil 11. Further, the main coil 11 is divided into three. 1
Reference numerals 3 to 15 denote the split coils. Each split coil 13 ~
Reference numeral 15 is connected between the lines (phases) of the lines 16 to 18 of the three-phase power supply via the rectifiers 19 to 21.

Each of the split coils 13 to 15 has an intermediate point 2
2 to 24, between each of the intermediate points 22 and 23, the intermediate point 2
3, 24, and the intermediate point 24 and the end 25 of the extension coil 12
Each split coil portion and extension coil between the rectifiers 26 to 28 are provided between the lines (interphases) of the lines 16 to 18 of the three-phase power supply.
Connected via The forward direction of the rectifiers 26 to 28 is
It is reversed from that of the rectifiers 19-21.

In the above configuration, when each of the lines 16 to 18 is connected to a three-phase power supply, a half-wave current having one of the positive and negative polarities, for example, a half-wave current having a positive polarity is supplied to each of the divided coils 13. 15 flows in the direction of the solid line arrow, and thereby the portions of the roller 1 corresponding to the divided coils 13 to 15 generate heat. In this case, as described above, the heat generation temperature at the portion corresponding to the central portion of each coil becomes higher.

Next, when the polarity of the three-phase current is reversed, a half-wave current of negative polarity is generated between the intermediate points 22 and 23, the intermediate points 23 and
24, the intermediate point 24, and the end portion 25 of the extension coil 25, flows in the direction of the dotted arrow, and the portion of the roller 1 corresponding to the coil portion where these currents flow generates heat. This is repeated below.

Here, in the heating state of the roller 1 when a half-wave current of negative polarity is flowing, the central portion between the intermediate points 22 and 23, the central portion between the intermediate points 23 and 24, and the intermediate point 2
4. The heat generation temperature at locations corresponding to the respective central portions between the ends 25 of the extension coils 25 increases. Comparing this with a state where a positive and a positive half-wave current is flowing, it is understood that the portion where the heat generation temperature of the roller 1 becomes high moves along the axial direction.

By moving the portion of the roller 1 where the heat generation temperature is high as described above, the portion of the roller 1 corresponding to each of the divided coils 13 to 15 is not maintained at the low heat generation temperature. The exothermic temperature at that location can be raised.

FIG. 4 shows a heat generation distribution at locations corresponding to the respective coil portions of the roller 1 which has generated heat in this way. The curve shown by the dotted line in the figure shows the heat value generated by the three-phase current, and the curve shown by the solid line is the combined heat value. In this manner, the temperature of the peripheral wall of the roller 1 is surely made uniform when the induction coil is simply heated by the three-phase current, that is, as is clear from the heat generation distribution shown in FIG.

The rectifiers 19 to 21 and 26 to 28
May be an ordinary diode or a thyristor as shown in the figure. If a thyristor is used, the firing angle of the thyristor can be controlled to adjust the current flowing through each coil, thereby adjusting the heat generation temperature of the roller 1.

Although the above embodiment shows a configuration in which the main coil 11 is divided into three, the main coil 11 may be divided into two or more multiples of three instead.
Even in this case, the divided coils are connected between the respective phases by the same number.

[0021]

As described above, according to the present invention, even when an induction coil in an electromagnetic induction heating mechanism for inducing heat generation in a roller is excited by a three-phase power supply, the heat generation distribution of the roller can be sufficiently flattened. Play the fruits you can.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view of FIG.

FIG. 3 is a circuit diagram of the induction coil of FIG. 1;

FIG. 4 is a heat generation distribution diagram of the roller in FIG. 1;

FIG. 5 is a heat generation distribution diagram of a roller in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Roller 2 Induction coil 3 Electromagnetic induction heating mechanism 4 Jacket room 11 Main coil 12 Extension coil 13-15 Split coil 16-18 Three-phase line 19-21 Rectifier 22-24 Intermediate point 25 Extension coil end 26-28 Rectification apparatus

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H05B 6/14 B29C 54/04 D02J 13/00 D21G 1/02 F16C 13/00

Claims (1)

(57) [Claims] 1. A roller driven by rotation, and an electromagnetic induction heating mechanism provided inside the roller and having an induction coil for inducing heat generation in the roller, and a two-phase gas-liquid inside a peripheral wall of the roller. In the induction heating roller device provided with a jacket chamber enclosing the heat medium, the induction coil is constituted by a main coil and an extension coil, and the main coil is divided into multiples of 3, and each divided coil is Connected via a rectifier so that a half-wave current of one of the positive and negative polarities flows between each phase of the three-phase power supply for each of the same number, and an intermediate point of each of the divided coils and an end of the extended coil. And an induction heating roller device connected between the respective phases of the three-phase power supply via a rectifier so that a half-wave current of the other polarity of each phase flows.