JP4176294B2 - Induction heating roller device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an induction heat roller device.
[0002]
[Prior art]
As is well known, the induction heating roller device includes 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 with respect to a gantry 3 and is driven to rotate by a rotation source (not shown). Reference numeral 5 denotes a jacket chamber formed in the thick portion of the roller 1, in which a gas-liquid two-phase heat medium is enclosed.
[0003]
In the hollow interior of the roller 1, an induction heating mechanism 8 configured by induction coils 61 to 63 and an iron core 7 around which the induction coils 61 to 63 are wound is installed. Reference numeral 9 denotes a support rod that supports the induction heat generating mechanism 8, and this is supported inside the journal 11 via a bearing 10. A lead wire 12 of the induction coil 5 is led out through the support rod 9 and connected to an external three-phase AC power source 13.
[0004]
By the way, a three-phase power source is used for exciting the induction coil. This is based on the fact that the three-phase power supply is familiar. However, when a symmetrical three-phase voltage is applied to the induction coil, a magnetic flow is generated in the roller portion facing the induction coil, and the magnetic flux passing through the roller may be non-uniform.
[0005]
Explaining 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. In this configuration, since the phase difference of the phase voltage is 120 degrees, the surface temperature of the roller portion facing between the adjacent induction coils is reduced with respect to the induction coil. As shown in FIG. 2, the U, V, and W phases are shifted by 180 degrees to form X, Y, and Z phases, and the V phase is shifted by 180 degrees in order to prevent it from becoming extremely lower than the wrinkled part. When the Y phase and the U and W phases are used, the phase difference between the U, Y, and W phases is 60 degrees.
[0006]
In this case, the Y phase is a phase advanced by 60 degrees relative to the U phase, and the W phase is a phase advanced by 60 degrees relative to the Y phase. When induction coils 61, 62, and 63 are connected to the U, Y, and W phases, respectively, and the roller 1 is inductively heated, for example, when the U phase is used as a reference, the phase of the leading phase is further increased from the roller portion facing the induction coil 61. A large amount of magnetic flux flows toward the roller portion facing the Y-phase induction coil 62. 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 that is advanced from the Y phase. Such a phenomenon is called magnetic flow.
[0007]
That is, as shown in FIG. 4, as a result of the magnetic flux flowing from the induction coil 63 toward the induction coil 61, the heat generation distribution curve A has a high portion facing the induction coil 61, and gradually increases according to the portions facing the induction coils 62 and 63. Shows a tendency to lower. Therefore, when such a magnetic flow phenomenon occurs, even when the same power is supplied to each induction coil, the surface temperature of the roller portion facing each induction coil becomes non-uniform, and the surface temperature distribution is smoothed. Will not be able to.
[0008]
[Problems to be solved by the invention]
The present invention improves the non-uniformity of heat generation of a roller due to a magnetic flow generated according to a phase advance direction or a delay direction of a phase voltage when exciting an induction coil inside the roller by a multiphase AC power source. With the goal.
[0009]
[Means for Solving the Problems]
The present invention, in the interior of the roller, first along the axial direction of the roller, the second, being arranged in sequential series with the third, of the induction coil for induction heating mechanism, to the first free In an induction heating roller device comprising a three-phase AC power source having a first phase, a second phase, and a third phase for exciting a third induction coil, adjacent to one end of the first induction coil and the first induction coil One end of the second induction coil on the side and one end of the third induction coil opposite to the second induction coil are connected to each other, and the other end of the second induction coil is connected to the three-phase alternating current Connect to the second phase of the power supply, and connect the first phase and the third phase of the three-phase AC power source connected to the other end of the first induction coil and the other end of the third induction coil at predetermined time intervals. A control means for switching is provided .
[0010]
In the first application state in which the first phase of the three-phase AC power supply is connected to the other end of the first induction coil and the third phase of the three-phase AC power supply is connected to the other end of the third induction coil, The roller portion facing the third induction coil at the end of the roller has the largest amount of heat generation, and the roller portion facing the first induction coil at the other end has the least amount of heat generation. After this state is continued for a predetermined time , the third phase of the three-phase AC power source is connected to the other end of the first induction coil, and the first phase of the three-phase AC power source is connected to the other end of the third induction coil . Switch to 2 application state. This reverses the magnitude relationship between the heat generation amounts of the induction coils.
[0011]
This second application state is continued for a predetermined time. After that, it switches to the first application state again. This is repeated below. As a result, the heat generation amount of the roller portion is an average value of the heat generation amount in the first application state and the heat generation amount in the second application state. This makes it almost uniform along the axial direction of the roller, so that the surface temperature of the roller is averaged.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described with reference to FIG. FIG. 2 shows an example in which U-phase, V-phase, and W-phase three-phase lines are star-connected and three induction coils 61, 62, and 63 are used. Then, the U and W phases and the Y phase of the X, Y and Z phases obtained by shifting the U, V and W phases by 180 degrees are used. Induction coils 61 to 63 are connected to the U, Y, and W phase lines. Further, as shown in FIGS. 1 and 3, the induction coil 61 to the induction coil 63 are sequentially arranged in series inside the roller 1.
[0013]
Reference numeral 15 denotes a control device that performs control so as to alternately switch between the first application state and the second application state, and is constituted by six changeover switches S here. Each changeover switch S has an a contact and a b contact. When each changeover switch S is in a state in which the contact a is closed as shown in the figure, U-phase, Y-phase, and W-phase voltages are respectively applied to the induction coils 61 to 63 (first application state). .
[0014]
As a result, the roller generates induction heat, but due to the magnetic flow, the heat generation amount of the roller portion facing the induction coil 61 is the largest, and the heat generation amount of the roller portion facing the induction coil 63 is the lowest (the heat generation distribution in FIG. 4). (See curve A). After this state has passed for a predetermined period of time, more specifically, due to a difference in thermal expansion based on unevenness in the heat distribution of the roller , a changeover switch after a heat generation time (for example, within a few minutes) that does not affect the use of the roller diameter has been affected. S is switched from contact a to contact b. As a result, the phase advance relationship of each phase is reversed, and W-phase, Y-phase, and U-phase voltages are respectively applied to the induction coils 61 to 63 (second application state).
[0015]
This also continues the induction heat generation of the roller, but in this state, the heat generated in the roller portion facing the induction coil 63 is the largest due to the magnetic flow, contrary to the first state. The amount of heat generated at the wrinkling roller portion is the lowest (see heat generation distribution curve B in FIG. 4). After this state has passed for a predetermined time, that is, the time described above, the changeover switch S is again switched from the b contact to the a contact. This is repeated below.
[0016]
As described above, when the first and second application states are alternately repeated, the heat generation amount of the roller portion facing 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. A value comparable to the average value of the calorific value of No. 2 is obtained (see the exothermic distribution curve C in FIG. 4). As a result, the surface temperature of the roller can be made more uniform by avoiding the influence due to the imbalance of the amount of heat generated by the magnetic flow.
[0018]
【The invention's effect】
As described above, according to the present invention, when the induction coil is excited by the three-phase AC power supply, it is possible to eliminate the imbalance of the heat generation amount of the roller based on the magnetic flow due to the phase advance and delay, and thus the roller. The surface temperature can be made uniform without being affected by the magnetic flow.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of the present invention.
FIG. 2 is a topographic 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]
1 Roller 61 Induction Coil 62 Induction Coil 63 Induction Coil 8 Induction Heating Mechanism 15 Control Device

Claims (1)

A rotating roller, and an induction coil for the induction heating mechanism, which is disposed inside the hollow of the roller and is arranged in series with the first, second, and third sequentially along the axial direction of the roller; In the induction heat roller apparatus comprising a three-phase AC power source having a first phase, a second phase, and a third phase for exciting the first to third induction coils, one end of the first induction coil and the first induction One end of the second induction coil adjacent to the coil and the other end of the third induction coil adjacent to the second induction coil are connected, and the other end of the second induction coil is connected to the other end of the second induction coil. A first phase and a third phase of the three-phase AC power source connected to the second phase of the three-phase AC power source and connected to the other end of the first induction coil and the other end of the third induction coil are predetermined. induction heating, characterized in that a control means for switching every time Over La apparatus.

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