JP2001250669A - Induction heating roller device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable applying AC voltage with small phase difference only by connecting induction coils mutually without using multi-phase transformer when a plurality of induction coils, with three-phase power source, are exited. SOLUTION: The induction coils, standing in a line along the direction of axis center of roll, are divided into the first group, to which the three-phase voltage is applied and the second group, to which the voltage with inverted phase is applied, and the third and fourth groups, to which the voltage, synthesized from the divided voltage of the induction coils of the first and the second groups, so as to have the phase difference of less than 60 degree against the exiting voltage of adjacent induction coils, is impressed.

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 roll device has an induction heating mechanism including an iron core and an induction coil wound around the inside of a rotating roll. An example of this configuration will be described with reference to FIG. 6. Reference numeral 1 denotes a roll, which is rotatably supported by a bearing 3 with respect to a gantry 2 and is rotationally driven by a rotation source (not shown). Reference numeral 4 denotes a jacket chamber formed in a thick portion of the roll 1, and a gas-liquid two-phase heat medium is sealed therein.

In the hollow interior of the roll 1, an induction heating mechanism 7 is constituted by a plurality of induction coils 5 and an iron core 6 around which the coils are wound. Numeral 8 is a magnetic disk interposed between the induction coils, and 9 is a support rod for supporting the induction heating mechanism 7, which is supported inside a journal 11 connected to the roll 1 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 AC power supply.

[0004] A three-phase power supply is used to excite an induction coil. This is based on the fact that the three-phase power supply is nearby, but as is well known, since the phase difference between the U, V, and W phase voltages of the three-phase power supply is 120 degrees, three induction coils are prepared. It is known that when each of the phase voltages is applied to each of them, the surface temperature is lower at two locations of the roll passing between adjacent induction coils than at other locations.

In order to reduce this temperature drop, it is necessary to reduce the phase difference between voltages applied to adjacent induction coils. There has already been proposed a configuration in which a polyphase transformer for generating a secondary voltage is prepared, and each of the secondary voltages is applied to each of four or more prepared induction coils. -7754).

According to this, since the phase difference between the voltages applied to the adjacent induction coils can be made smaller than 120 degrees, the local difference on the roll surface is smaller than when three-phase voltages are applied to the induction coils as they are. Temperature drop can be reduced. However, this configuration requires the use of a multi-phase transformer, so that the manufacturing cost is increased and the installation site for installing the multi-phase transformer is required.

[0007]

SUMMARY OF THE INVENTION The present invention uses a three-phase power source as a power source, and provides a multi-phase power supply having a small phase difference between adjacent induction coils among a plurality of induction coils disposed inside a hollow portion of a roll. It is an object of the present invention to make it possible to apply an AC voltage having a small phase difference from a three-phase power supply only by connecting the induction coils without using a polyphase transformer in applying each of the AC voltages.

[0008]

SUMMARY OF THE INVENTION The present invention provides a 6 (N + 1) (where N is the number of) induction heating mechanisms inside a roll and arranged in series along the axial direction of the roll.
Is an integer greater than or equal to 1), a first group of delta-connected induction coils excited by the line voltage of the three-phase power supply, and each of the first group of induction coils along the direction of phase rotation. A second group of induction coils, which are arranged between the two groups and are excited by a voltage shifted by 180 degrees from the voltage of the three-phase power supply, and a second group of induction coils arranged between the first and second groups of induction coils. The third and fourth groups of induction coils are divided by 60 degrees / (N + 1) with respect to the excitation voltages of other adjacent induction coils along the phase rotation direction. (1) Excitation is performed by a voltage obtained by combining the divided voltages of the induction coils of the first and second groups so as to have a phase difference of (1).

[0009] All induction coils are sequentially 60 degrees /
Since a voltage having a phase difference of (N + 1) is applied, it is the same as applying the secondary voltages of the multi-phase transformer.
For that purpose, since it is implemented only by connecting the induction coils, a polyphase transformer is not required.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 6, when twelve induction coils 5 are prepared and delta-connected, the phase difference between voltages applied to adjacent induction coils is 30 degrees in the present invention. FIG. 1 shows the connection relationship of the induction coil to the three-phase power supply in this case.

In FIG. 1, A1 to A3 are U, V, W
The first group of induction coils, B1-B3, which are delta-connected between each phase of the three-phase power supply, are derived from the same three-phase power supply and are 18 volts for the U, V, W phase voltages.
U, V, W so that the voltage shifted by 0 degrees is extracted.
And a second group of induction coils connected between the X, Y, and Z phases, which are the phases connected to the respective phases.

C1 to C3 are a third group of induction coils connected between adjacent induction coils of the first group, and D1 to D3 are a second group of induction coils. Is a fourth group of induction coils connected between adjacent induction coils.

This will be described in detail.
Is between taps u and v of induction coils A1 and A2, induction coil C2 is between taps v and w of induction coils A2 and A3, and induction coil C3 is between taps w and u of induction coils A3 and A1. Each is connected. Similarly, the induction coil D1 is located between the taps x and y of the induction coils B1 and B2.
The induction coil D2 has taps y, of the induction coils B2 and B3.
Between z, the induction coil D3 is connected between the taps z and x of the induction coils B3 and B1, respectively.

The third and fourth induction coils connected in this manner are connected to the first and second induction coils to which they are connected.
Is applied. In this case, the taps u, v, w, x, y, and z are set so that the phase difference between the voltages applied to the adjacent induction coils is 30 degrees by the combined applied voltage. FIG. 2 shows a topographical map of the connection diagram shown in FIG. 1, and FIG. 3 generally shows this by separating the triangle UVW and the triangle XYZ and setting the phase difference to θ. FIG. 4 shows that the phase difference θ is 30 degrees.

As can be seen from these, the triangle UV
In W, the tilt angle of uv with respect to UV, v with respect to VW
The inclination angle of w and the inclination angle of wu with respect to WU are each 30 degrees. Similarly, in the triangle XYZ, x with respect to XY
tilt angle of y, tilt angle of yz with respect to YZ, zx with respect to ZX
Are also 30 degrees.

Therefore, the induction coils A1, C1, B
3, D3, A2, C2, B1, D1, A3, C3, B
2, D2 are arranged in the hollow interior of the roll 1 in the order shown in FIG.
, ZX, zx, VW, vw, XY, xy
If a voltage is applied between the induction coils, between the WU, between the wu, between the YZ, and the yz, the phase difference between the voltages applied to the adjacent induction coils becomes 30 degrees. The starting point of this order may be anywhere, and the order of the order may be reversed.

Here, the line voltages of the U, V, and W phases are E,
If the voltage between Uu is E1, the voltage between uV is E2, and the voltage between uv is E3, then E = E1 + E2 E1 = E2 sin30 °, so that E1 = E / 3 E2 = 2E / 3 and E3 = E2cos30 ° = (2E / 3) × cos30 °

That is, with respect to the voltage E applied to the induction coil A1, the positions of the taps u and v are selected to select the voltage E
If 1, E2 and E3 are applied to each induction coil, the phase difference between the voltages applied to the induction coils A1 and C1 becomes 30 degrees. If the positions of the taps w, x, y, and z are selected in the same manner for the other induction coils, the phase difference between the voltages applied to the adjacent induction coils is 30 degrees. For example, the number of turns, the coil width, the resistance, and the like are set so that the heating temperature of the roll 1 by each induction coil is the same, and the ampere turn per roll surface length of each induction coil is the same.

FIGS. 7 to 9 show a configuration in which N is set to 3. FIG. Therefore, the number of induction coils is 24
In this configuration, the phase difference between the voltages of adjacent induction coils is 15 degrees. The U, V, W phases and the X, Y, Z phases are the same as in FIG. FIG. 7 corresponding to FIG.
As shown in the topographic map, each of the induction coils A1 to A
Taps u1 to u3, v1 to v3 and B1 to B3
3, w1 to w3, x1 to x3, y1 to y3, z1 to z3
Has been pulled out.

In the triangle UVW, the tilt angle of u1v1 with respect to UV, the tilt angle of v1w1 with respect to VW, WU
The inclination angle of wu with respect to -15 degrees, the inclination angle of u2v2 with respect to UV, the inclination angle of v2w2 with respect to VW, the inclination angle of w2u2 with respect to WU are each 15 degrees, the inclination angle of u3v3 with respect to UV, the inclination angle of v3w3 with respect to VW, and the inclination angle of w3u3 with respect to WU. Set each to 30 degrees.

Similarly, in the triangle XYZ, the inclination angle of x1y1 with respect to XY, the inclination angle of y1z1 with respect to YZ, ZX
The angle of inclination of z1x1 with respect to -15 degrees, x2 with respect to XY
The inclination angle of y2, the inclination angle of y2z2 with respect to YZ, the inclination angle of z2x2 with respect to ZX is 15 degrees, the inclination angle of x3y3 with respect to XY, the inclination angle of y3z3 with respect to YZ, and the z3x with respect to ZX.
The inclination angle of 3 is set to 30 degrees.

The first group of induction coils A1 to A3 and the second group of induction coils B1 to B3 are UVW
It is connected between the phases and between the XYZ phases. The third group consists of three groups, of which the induction coils C1 to C3 of the first group are connected between u3v3 and v3.
connected between w3 and w3u3, the induction coils C21 to C23 of the next group are connected between u2v2, between v2w2, w2
u2, and the next group of induction coils C31 to C31.
C33 is connected between u1v1, v1w1, and w1u1.

The fourth group also consists of three groups, of which the first group includes induction coils D1 to D3.
Is connected between x3y3, between y3z3, and between z3x3,
The next group of induction coils D21 to D23 is x1y1
, Z1x1, z1x1, and the next group of induction coils D31 to D33 are connected between x2y2 and y2z2.
And z2x2.

These 24 induction coils are arranged in the hollow interior of the roll 1 in the order of the induction coil C31 to the induction coil D2 as shown in FIG. When the voltage between the taps is applied, the phase difference between the voltages applied to the adjacent induction coils becomes 15 degrees. The starting point of this order may be anywhere, and the order of the order may be reversed.

Here, E is the line voltage of the U, V, and W phases,
If the voltage between U-u3 is E1, and the voltage between u3-V is E2, then E = E1 + E2 E1 = E2 × sin30 °, so that E1 = E / 3 E2 = 2E / 3. If the voltage between u3 and v3 is E3, then E3 = 2Ecos30 ° / 3.

Further, between U-u1, between U-v1, and between u1-
Assuming that the voltages between v1 are E4, E5, and E6, from the sine theorem, E4 / sin15 ° = E5 / sin105 ° = E6 / sin60
° Here, since E5 = E−E4, E4 / sin15 ° = (E−E4) / sin105 ° If this is arranged, E4 = Esin15 ° / (2sin60 ° cos45 °) Similarly, E5 = Esin105 ° / (2 sin60 ° cos45 °) E6 = E / (2cos45 °)

That is, with respect to the voltage E applied to the induction coil A1, if the positions of the taps u and v are selected and the voltages E1 to E6 are set, the phase difference of the voltage applied to the induction coil becomes 15 Degree. If the positions of the taps w, x, y, and z are selected in the same manner for the other induction coils, the phase difference between the voltages applied to the adjacent induction coils is one.
5 degrees. For example, the number of turns, the coil width, the resistance, and the like are set so that the heating temperature of the roll 1 by each induction coil is the same, and the ampere turn per roll surface length of each induction coil is the same.

In the example described above, N is 1 and 3, so that the phase difference between the voltages of the adjacent induction coils is 30 degrees and 15 degrees. However, the present invention is not limited to this. It goes without saying that any integer greater than or equal to one can be applied. For example, if N is 2, the number of induction coils can be 18, and the phase difference can be 20 degrees.

Next, an embodiment in which the induction coil is star-connected to the three-phase power supply will be described. This uses 3 (N + 1) induction coils star-connected (neutral the neutral point). As shown in FIG.
The first group of induction coils is connected to the VW phase, and the second group of induction coils is connected to the XYZ phase obtained by shifting the phase by 180 degrees with respect to this phase. A second group of induction coils is disposed between the first group of induction coils.

A third group of induction coils is arranged between the first and second induction coils thus arranged. This induction coil has a phase difference θ ｛= 360 ° / phase with respect to the voltage applied to the adjacent first or second induction coil.
A voltage of 3 (N + 1)｝ is applied. N is 3, so that the number of induction coils is 12, and the phase difference θ is 30.
FIG. 11 shows a topographic map in the case of degrees.

Voltages Ne-u, Ne-z, Ne-v, Ne-x, Ne- applied to the third group of induction coils
w, Ne-y overlaps the voltage between the neutral point Ne and the neutral point Ne of the voltage applied to the adjacent first and second groups of induction coils, and overlaps the first and second groups of induction coils. It is obtained as a voltage obtained by combining the voltage of the wound auxiliary coil. This intermediate point is defined as U1, Z1, V1, X1, W1,
Assuming that Y1, the voltage between Ne and U1 is U1
And u have a phase difference of 60 degrees.

FIG. 12 shows a connection state in which twelve induction coils are arranged side by side in the case where they are arranged inside the roller. A1 to A3 are the first group of induction coils, B1 to B3 are the second group of induction coils,
C11 to C13 and C21 to C23 are a third group of induction coils. Here, the auxiliary coils S11 to S1
3 and S21 to S23 are prepared.

The auxiliary coils S11 to S13 are induction coils A
1 to A3, auxiliary coils S21 to S23 are induction coils B
1 to B3 are wrapped around each other, and in-phase voltages are respectively induced. For this reason, a voltage obtained by combining a voltage applied to the first or second group of induction coils adjacent thereto with a phase difference of 30 degrees is applied to the induction coils C11 to C13 and C21 to C23. Become like

If the three-phase input voltage is E, the voltage between U and Ne is E1, the voltage between U and U1 is E2, the voltage between U1 and Ne is E3, and the voltage between u and Ne is E4, E1 = E2 + E3 = E4 = E / √3 Assuming that the voltage between u and U1 is E5, E3 = E5 = E4 / (2cos30 °) = E / (2√3cos
30 °) E2 = {1− (１ ／ cos 30 °)} × E / √3 The same applies to other phases. Therefore, U1, Z1, V1, X1, W1, and U1 satisfying these voltage values.
What is necessary is just to set the position of Y1.

Another embodiment of the present invention will be described. This shifts the voltage of one of the three star-connected phases by 180 degrees, and obtains three voltages each having a phase difference of 60 degrees. Further, voltages of adjacent phases along the phase rotation direction are combined to obtain a voltage having a phase difference θ of θ = 180 ° / {3 (N + 1)}.

FIG. 13 shows a topographic map for the configuration.
Of the three phases of the star-connected UVW phases, one of the phases, in the example shown in FIG.
And the phase is shifted to the -W phase. And the induction coil A for each phase
1, A2 and A3 are connected and arranged along the phase rotation direction. Moreover, between U-(-W) adjacent along the phase rotation direction,
(-W) Induction coils B1, B2, B between -V and V-U
3 are also arranged along the phase rotation direction.

The induction coils B1, B2, and B3 have:
A voltage having a phase difference θ of 180 ° / {3 (N + 1)} obtained by combining the divided voltages of other adjacent induction coils is applied. FIG.
2, FIG. 13 shows an example in which the phase difference θ is 30 degrees,
Therefore, here, six induction coils are used.

In this configuration, the input voltage is E, the neutral point N
e and the voltage between each U, u, -W, -w, V, and v is E1
Then, the voltage E2 between the neutral points Ne and U1 is E2 = E1 / 2cos30 ° = E / (2√3cos30 °). The voltage E2 is also equal to the voltage between u and U1. Further, if the voltage between U and U1 is E3, then E3 = E1-E2 = E {1-1 / (2 cos30 ° /｝)
3. The positions of U1, V1, and W1 that satisfy these voltages may be set.

[0039]

As described above, according to the present invention, when a plurality of induction coils arranged in series in a roll are excited by using a three-phase power supply, the level of the excitation voltage of adjacent induction coils is reduced. Since the combined voltage between the induction coils is used to reduce the phase difference to less than 60 degrees, it is not necessary to use a conventional polyphase transformer, so that the configuration is simplified and the polyphase transformer is simplified. This has the effect of eliminating the need for an installation place for the vessel.

[Brief description of the drawings]

FIG. 1 is a wiring diagram showing an embodiment of the present invention.

FIG. 2 is a topographic map in FIG.

FIG. 3 is a topographical map separately showing FIG. 2;

FIG. 4 is a topographic map with a phase difference of 30 degrees in FIG.

FIG. 5 is a wiring diagram in which the induction coils of FIG. 1 are arranged along a phase rotation direction.

FIG. 6 is a cross-sectional view of the induction heating roll device.

FIG. 7 is a topographic map with a phase difference of 15 degrees.

FIG. 8 is a wiring diagram when a phase difference is set to 15 degrees.

FIG. 9 is a wiring diagram in which the induction coils of FIG. 8 are arranged in the phase rotation direction.

FIG. 10 is a topographical view showing another embodiment of the present invention.

11 is a topographical map when the phase difference in FIG. 10 is 30 degrees.

FIG. 12 is a wiring diagram in which the induction coils in FIG. 10 are arranged along the phase rotation direction.

FIG. 13 is a topographic map showing another embodiment of the present invention.

FIG. 14 is a wiring diagram in which the induction coils in FIG. 13 are arranged along the phase rotation direction.

[Explanation of symbols]

 Reference Signs List 1 Roll 7 Induction heating mechanism A1 to A6 First group of induction coils B1 to B3 Second group of induction coils C1 to C1 Third group of induction coils D1 to D3 Fourth group of induction coils U, V, W Three-phase power supply X, Y, Z Voltage line shifted by 180 degrees

Claims (3)

[Claims] 1. A rotating roll and 6 (N + 1) (where N is 1) for an induction heating mechanism arranged inside the hollow of the roll and arranged in series in the axial direction of the roll. A first group of delta-connected induction coils, each of which comprises an integer number of induction coils and a three-phase power supply for exciting the induction coils, wherein the induction coils are excited by the line voltage of the three-phase power supply. And a second group of induction coils disposed between the induction coils of the first group along the phase rotation direction and excited by a voltage obtained by shifting the voltage of the three-phase power supply by 180 degrees. And a third and fourth group of induction coils disposed between the first and second group of induction coils,
The first and fourth groups of induction coils have a phase difference of 60 degrees / (N + 1) with respect to the excitation voltage of another induction coil adjacent in the phase rotation direction.
And an induction heating roller device which is excited by a voltage obtained by combining the divided voltages of the induction coils of the second group. 2. A rotating roll, and 3 (N + 3) (where N is 1) for an induction heating mechanism arranged inside the hollow of the roll and arranged in series along the axial direction of the roll. A first group of star-connected induction coils, each of which comprises an integer number of induction coils and a three-phase power supply for exciting the induction coils, wherein the induction coils are excited by the line voltage of the three-phase power supply. And a second group of induction coils disposed between the induction coils of the first group along the phase rotation direction and excited by a voltage obtained by shifting the voltage of the three-phase power supply by 180 degrees. And a third and fourth group of induction coils disposed between the first and second group of induction coils,
The third and fourth groups of induction coils have a phase difference of 360 degrees / {3 (N + 3)} with respect to the excitation voltage of another induction coil adjacent in the phase rotation direction.
An induction heating roller device which is excited by a voltage obtained by combining the divided voltages of the induction coils of the first and second groups. 3. A rotating roll, and 3 (N + 1) (where N is 1) for an induction heating mechanism disposed inside the hollow of the roll and arranged in series along the axial direction of the roll. The above-mentioned integer number of induction coils, and a three-phase power supply for exciting the induction coils, the induction coils are star-connected, and are excited by a voltage between two phases of the three-phase power supplies. And a first group of induction coils disposed between the first group of induction coils and the first group of induction coils along the direction of phase rotation. A second group of induction coils excited by a phase shifted voltage;
And a third group of induction coils disposed between the induction coils of the third group. The third group of induction coils is provided with an excitation voltage of another adjacent induction coil along the phase rotation direction. An induction heating roller device that is excited by a voltage obtained by combining the divided voltages of the induction coils of the first and second groups so as to have a phase difference of 180 degrees / {3 (N + 1)}.