JP2002075626A - Induction heat generating roller device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve ununiformity of calorific values of a roller caused by a magnetic current generated following to an advancing direction or a delaying direction of phase of a phase voltage when an induction coil inside the roller is magnetized by a multi-phase alternating current power supply. SOLUTION: Among the induction coils arranged sequentially inside the roller, this is equipped with a control means to alternately repeat the first applying state wherein the phase voltage which is to be advancing phase is sequentially applied from the induction coil in one end part toward the induction coil in the other end part, and the second applying state wherein the phase voltage which is to be a delaying phase is sequentially applied from the induction coil in the one end part toward the induction coil in the other end part in every prescribed period.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an induction heating roller device.

[0002]

2. Description of the Related Art As is well known, an induction heating roller device is provided with an induction heating mechanism including an iron core and an induction coil wound around the inside of a rotating roller. An example of this configuration will be described with reference to FIG. 1. Reference numeral 1 denotes a roller, and a journal 2 connected thereto is rotatably supported by a bearing 4 on a gantry 3 and is rotationally driven by a rotation source (not shown). Reference numeral 5 denotes a jacket chamber formed in a thick portion of the roller 1, in which a gas-liquid two-phase heat medium is sealed.

[0003] In the hollow interior of the roller 1, an induction coil 61 is provided.
An induction heat generating mechanism 8 is provided, which is constituted by .about.63 and an iron core 7 wound therewith. 9 is a support rod for supporting the induction heating mechanism 8, which is supported inside the journal 11 via a bearing 10. Numeral 12 denotes a lead wire of the induction coil 5, which is led out through the support rod 9 and connected to an external three-phase AC power supply 13.

[0004] A three-phase power supply is used to excite an induction coil. This is based on the familiarity of the three-phase power supply. However, when a symmetrical three-phase voltage is applied to the induction coil, a magnetic flow occurs in a roller portion facing the induction coil, and therefore, the magnetic flux passing through the roller may be non-uniform.

To explain this, as shown in FIG. 4, induction coils 61 to 63 are prepared, arranged inside the roller 1, and a three-phase voltage is applied to each induction coil. Note that the phase difference between the phase voltages may be 12 in this configuration.
Since it is 0 degrees, in order to reduce this phase difference so that the surface temperature of the roller portion passing between the adjacent induction coils does not become extremely lower than the position passing the induction coil, FIG. As shown in FIG. 5, the U, V, and W phases are shifted by 180 degrees to form X, Y, and Z phases. Of these, the Y phase obtained by shifting the V phase by 180 degrees and the U and W phases are used. The phase difference between the Y and W phases is 60 degrees.

In this case, the Y phase has a phase advanced by 60 degrees with respect to the U phase, and the W phase has a phase advanced by 60 degrees with respect to the Y phase. Induction coils 61 and 6 for U, Y and W phases respectively
When the roller 1 is caused to generate heat by induction, for example, on the basis of the U phase, the Y-phase induction coil 6 having a phase leading from the roller portion facing the induction coil 61 is moved forward.
A large amount of magnetic flux flows toward the roller portion facing 2. Similarly, a large amount of magnetic flux flows from the roller portion facing the induction coil 62 toward the roller portion facing the W-phase induction coil 63, which is ahead of the Y phase. Such a phenomenon is called magnetic flow.

That is, as shown in FIG.
As a result of the magnetic flux flowing from 3 to the induction coil 61, the heat generation distribution curve A has a high portion facing the induction coil 61,
It shows a tendency to gradually decrease as the portion faces the induction coils 62 and 63. Therefore, when such a magnetic flow phenomenon occurs, even if the same power is supplied to each induction coil, the surface temperature of the roller portion facing each induction coil becomes uneven, and the surface temperature distribution is smoothed. Will not be able to.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a method for exciting an induction coil inside a roller by a polyphase AC power supply.
It is an object of the present invention to improve non-uniformity of heat generation of a roller due to a magnetic flow generated according to a leading direction or a lagging direction of a phase voltage.

[0009]

SUMMARY OF THE INVENTION The present invention is directed to one end of an induction coil for an induction heating mechanism inside a roller and arranged in series along the axial direction of the roller. A first application state in which a phase voltage having a progressive phase is sequentially applied to the induction coil from the induction coil at the end toward the induction coil at the other end; and the induction coil at the one end. And a second application state of sequentially applying a phase voltage having a sequentially delayed phase to the induction coil toward the induction coil at the other end from a predetermined time. It is characterized by having.

In the first applied state, the amount of heat generated by the roller portion passing through the induction coil at one end is the largest due to the magnetic flow, and the amount of heat generated by the roller portion passing through the induction coil at the other end is generated. The least amount. After this state is continued for a predetermined time, the state is switched to the second application state. As a result, the magnitude relationship between the heat values of the induction coils is reversed.

The second application state is continued for a predetermined time. After that, the state is switched to the first application state again. This is repeated below. As a result, the heat value of the roller portion is an average value of the heat value in the first application state and the heat value in the second application state. This results in a substantially uniform along the axial direction of the roller, thus averaging the roller surface temperature.

[0012]

An embodiment of the present invention will be described with reference to FIG. FIG. 2 shows an example in which U-, V-, and W-phase three-phase lines are star-connected, and three induction coils 61, 62, and 63 are used. And U, W phase, U, V, W
The phase is used by shifting the phase by 180 degrees and using the Y phase among the X, Y, and Z phases. An induction coil 6 is connected to each of the U, Y, and W phase lines.
1 to 63 are connected. 1 and 3 inside the roller 1.
As shown in (1), the induction coil 61 to the induction coil 63 are sequentially arranged in series.

Reference numeral 15 denotes a control device for performing control so as to alternately switch between the first application state and the second application state, and here is constituted by six changeover switches S. Each changeover switch S has an a contact and a b contact.
When each switch S is in a state where the a contact is closed as shown in the figure, the induction coils 61 to 63 have U-phase, Y-phase, and W-phase.
Phase voltages are respectively applied (first applied state).

As a result, the roller generates heat by induction, but the amount of heat generated by the roller portion passing through the induction coil 61 due to the magnetic flow is the largest, and the amount of heat generated by the roller portion passing through the induction coil 63 is minimized (FIG. 4). Heat generation distribution curve A). In this state, after a predetermined time, specifically, a time (for example, about several minutes) required for the surface temperature of the roller to stabilize, the changeover switch S is switched from the a contact to the b contact. This reverses the leading relationship of each phase,
W-phase, Y-phase, and U-phase voltages are respectively applied to the induction coils 61 to 63 (second applied state).

In this state, the induced heat generation of the roller is continued, but in this state, the amount of heat generated in the roller portion passing through the induction coil 63 is the largest due to the magnetic flow, contrary to the first state. The calorific value of the roller portion corresponding to 61 is the lowest (see the heat generation distribution curve B in FIG. 4). In this state, after a predetermined time, that is, the above-described time has elapsed, the changeover switch S is switched from the b contact to the a contact again. This is repeated below.

When the first and second application states are alternately repeated as described above, the heat generation amount of the roller portion passing through the induction coils 61 to 63 becomes the heat generation amount in the first application state and the heat generation amount in the second application state.
At the time of application of the current value and a value comparable to the average value of the heat value at the time of the application state (see the heat generation distribution curve C in FIG. 4). As a result, the effect of the surface temperature of the roller due to the imbalance of the calorific value due to the magnetic flow is avoided, and the roller surface becomes more uniform.

Although the above embodiment has been described in connection with the case where a three-phase power supply is used, the present invention is not limited to this.
The present invention can be applied even when a multi-phase power source obtained by multiplying three phases by an integer is used. Also, the phase difference applied to adjacent induction coils is 60
Although the angle is set to degrees, it may be larger than 60 degrees, for example, 120 degrees, or may be smaller than 60 degrees, for example, 30 degrees. Further, the number of induction coils is not limited to three, but may be 3n (an integer of 2 or more) according to the number of phases of the power supply.

[0018]

As described above, according to the present invention, when the induction coil is excited by the polyphase AC power supply, the imbalance of the calorific value of the roller due to the magnetic flow due to the phase advance and delay is eliminated. Thus, the surface temperature of the roller can be made uniform without being affected by the magnetic flow.

[Brief description of the drawings]

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

FIG. 2 is a topographical map of an induction coil.

FIG. 3 is a wiring diagram showing an embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a relationship between an induction coil and a heat generation amount.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Roller 61 Induction coil 62 Induction coil 63 Induction coil 8 Induction heating mechanism 15 Controller

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[Procedure amendment]

[Submission date] September 20, 2000 (2009.2)
0)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction contents]

As a result, the roller generates heat by induction, but the amount of heat generated by the roller portion passing through the induction coil 61 due to the magnetic flow is the largest, and the amount of heat generated by the roller portion passing through the induction coil 63 is minimized (FIG. 4). Heat generation distribution curve A). The state for a predetermined time, specifically heating rollers
The difference in thermal expansion based on uneven distribution can also
Heating time such that the change does not affect use (for example, several minutes)
After a lapse of less than), b the change-over switch S from a contact
Switch to contacts. As a result, the leading relationship between the phases is reversed, and the W-phase, Y-phase, and U-phase voltages are applied to the induction coils 61 to 63 (second application state).

Claims (1)

[Claims] 1. A rotating roller, a plurality of induction coils for an induction heating mechanism, arranged inside the hollow of the roller and arranged in series in the axial direction of the roller, and the induction coil. In an induction heating roller device comprising a multi-phase AC power supply for exciting coils, the induction coils arranged in sequence sequentially proceed from the induction coil at one end to the induction coil at the other end. A phase voltage having a phase of
And applying a phase voltage having a sequentially delayed phase from the induction coil at the one end to the induction coil at the other end in order to excite the second induction coil. An induction heating roller device comprising control means for alternately repeating an application state at predetermined time intervals.