JPH1072154A - Meandering preventive device for steel plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a plant and equipment investment, and enhance reliability to prevent meandering by arranging like-pole magnets in upper and lower parts in at least shaft directional both end parts of a steel plate so as to be opposed to each other. SOLUTION: Magnets M1 and M2 are fixedly arranged in upper and lower parts P1 and P2 in both end parts C1 and C2 of a steel plate P. At this time, like-poles are opposed to each other, and vertical directional attraction force is sharply reduced. A clearance (a) between the magnets M1 and M2 and the steel plate P is properly determined by magnetic force of the magnets M1 and M2, dead weight of the steel plate P and line tensile force or the like. By the constitution using such a single magnet, when the steel plate meanders, large attraction force acts, and it can be restored to a former position, and since vertical directional attraction force is weak, the qualitative deterioration by attraction of the magnet can also be made uncausal. A magnet width is set not less than a variable range of a plate width, and since attraction force is made to always act on the edge of the plate, electric control is obviated, so that a device can be simplified, and an investment can sharply be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a meandering preventing device for a steel plate. More specifically, the present invention relates to a meandering preventing apparatus for a steel sheet that can prevent meandering of a strip-shaped steel sheet passed through a continuous annealing furnace, a continuous surface treatment line, or the like.

[0002]

2. Description of the Related Art Conventionally, various devices have been proposed for passing a belt-shaped steel sheet while suppressing the meandering of the steel sheet in a non-contact state. For example, an end position detecting device for detecting the position of the end of the steel sheet, a permanent magnet arranged adjacent to a position where the end of the steel sheet passes, and for attracting the steel sheet by magnetic force, There is an adjusting device for adjusting the position of the permanent magnet through a control device in accordance with a signal from the position detecting device, and there is a device that controls the meandering while controlling the position of the permanent magnet by the meandering amount of the steel plate. (Japanese Unexamined Patent Publication No. 57-57
No. 19107). Further, an electromagnet protruding from both left and right ends of the steel sheet with respect to the moving direction of the steel sheet, and magnet supporting means for supporting the electromagnet movably in the left and right direction of the steel sheet, while utilizing the attraction force in the width direction of the electromagnet. And a meandering control (Japanese Utility Model Laid-Open No. 1-153804). Further, a pair of conductor rolls that energize the steel sheet to be passed, and a pair of electromagnets that are arranged with both ends of the steel sheet traveling between the conductor rolls and that provide an electromagnetic force that constantly pulls the steel sheet in the width direction, A detector for detecting the amount of meandering of the steel plate, and a controller for controlling the electromagnetic force generated by the electromagnet based on the amount of meandering of the steel plate, while applying a current to the steel plate, applying a magnetic field in a direction perpendicular thereto. In some cases, a meandering control is performed by applying a tensile force in the width direction of the steel sheet to apply the tension (see Japanese Utility Model Application Laid-Open No. Hei.
No. 7260).

[0003]

However, in the apparatus disclosed in Japanese Patent Application Laid-Open No. 57-19107, a meandering control device is required, which increases equipment costs and reduces the line tension for pulling a steel sheet. The steel plate may be attracted to the magnet and the steel plate may come into contact with the magnet, causing a flaw at the width edge.

On the other hand, in the device disclosed in Japanese Utility Model Application Laid-Open No. 1-153804, a levitation force (attraction force) caused by an exciting current of an electromagnet.
The balance between the steel plate and the plate's own weight prevents the steel plate from being attracted to the electromagnet.However, if the steel plate approaches the electromagnet, the levitation force increases. Requires a complicated control device.

In the apparatus disclosed in Japanese Utility Model Laid-Open Publication No. 1-177260, a current supply device for supplying an electric current to the steel sheet is required, so that the equipment cost is increased and there is a concern that the steel sheet may be sparked.

SUMMARY OF THE INVENTION In view of the circumstances described above, an object of the present invention is to provide a steel sheet meandering prevention device capable of reducing capital investment and improving the reliability of meandering prevention.

[0007]

A meandering preventing device for a steel sheet according to the present invention is a meandering preventing device for preventing meandering of a strip-shaped steel sheet continuously passed therethrough. It is characterized in that magnets of the same polarity are arranged so as to face upper and lower portions at both ends.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A steel sheet meandering prevention device according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is an explanatory view showing an embodiment of a meandering preventing device for a steel sheet according to the present invention, FIG. 2 is a diagram showing pressure acting on a magnetic field, and FIGS. FIG. 5, FIG. 5 is an explanatory view showing another arrangement of the magnet in FIG. 1, FIG. 6 is an explanatory view showing another embodiment of the present invention, FIG. 7 is an explanatory view showing another arrangement of the magnet in FIG. FIG. 8 shows FIG.
FIG. 9 is an explanatory diagram showing an arrangement relationship between the magnet and the steel plate in FIG. 7, FIG. 9 is an explanatory diagram showing an arrangement relationship between the magnet and the steel plate in FIG. 7, and FIG. 10 is a schematic diagram showing the attraction force of the magnet in FIGS.

As shown in FIG. 1, the meandering preventing device is disposed in a feeding path of a strip-shaped steel sheet P which is continuously passed therethrough to prevent the meandering of the steel sheet P and keep the steel sheet P at the center of the line at all times. This is a device for control, and is composed of magnets M1 and M2 fixed to the upper and lower portions P1 and P2 at both ends C1 and C2 of the steel plate P such that the same poles face each other. It is one of the features of the present invention that the suction force in the vertical direction is greatly reduced by making the same poles face each other. As the magnets M1 and M2, a permanent magnet such as a ferrite magnet or a rare earth magnet, an electromagnet, or a combination of a permanent magnet and an electromagnet can be used. Each magnet M
In the fixing method of 1 to M2, for example, a nonmagnetic material is inserted between a gantry supporting the entire magnet and the magnet, and each is fixed with a bolt.

The gap a between each of the magnets M1 and M2 and the steel plate P is appropriately determined by the magnetic force of each of the magnets M1 and M2, the weight of the steel plate P, the line tension of the steel plate P, and the like. Even if a steel plate having a poor shape such as a drop or an ear wave material comes, it is determined to be as small as possible within a range where the steel plate does not come into contact with the magnet and to increase a suction force in a width direction necessary for preventing meandering. In addition, even when the magnets M1 and M2 have different magnetic forces, by changing the ratio of the gap a at the upper portion to the gap a at the lower portion, it is possible to prevent the generation of an attractive force between the steel plate and the magnet M1 or M2. .

Next, correction of meandering by the meandering prevention device of the present embodiment will be described. First, assuming that the space is filled with a magnetic flux tube which is regarded as a tube passing one magnetic flux from a unit positive magnetic pole to a negative magnetic pole, as shown in FIG. 2, the contraction force is applied to the direction of the magnetic field H (the direction of the tube). And a pressure p of the same magnitude acts in a direction perpendicular to the magnetic field H (Maxwell's strain force). The pressure p is expressed by the following equation, where B is the magnetic flux density and μ is the magnetic permeability in the magnetic flux tube.

[0013]

(Equation 1)

Next, as shown in FIG.
If it is meandering to the right from 1 to M2, the suction force p (pressure) in the width direction in the region R1 shown in FIG.
(See (a)) is given by the following equation.

[0015]

(Equation 2)

[0016]

(Equation 3)

B ₁ : magnetic flux density at the boundary between air and steel sheet (0.4 to 0.5 wb / m ² ) μ _o : magnetic permeability in air (1.257 × 10 ^-6 H / m) μ _s : Permeability of the steel sheet (100 to 1000 H / m).

On the other hand, the suction force p (pressure) in the width direction in the region R2 shown in FIG. 3 (see FIG. 4B) is given by the following equation.

[0019]

(Equation 4)

[0020]

(Equation 5)

B _{2 is} the magnetic flux density (0.2 to 0.3 wb / m ² ) at the boundary between the air and the steel sheet.

Since the relationship between the expressions (2) and (3) is μ _s ≫1, p _a1 > p _s1 ‥‥‥ (6), and the relationship between the expressions (4) and (5) is Similarly, p _a2 > p _s2 ‥‥‥ (7).

Therefore, from the above equations (6) and (7),
Since B ₁ > B ₂ , p _a1 > p _a2 ‥‥‥ (8), and the steel sheet P moves to the left.

In this embodiment, when a steel sheet meanders using a single magnet, a large attractive force acts to restore the steel sheet to its original position. Further, since the poles are fixed so as to face each other, suction in the vertical direction is weak, so that the steel sheet is attracted to the magnet, and the quality does not deteriorate. In addition, since the magnetic attraction force always acts on the edge of the plate by setting the magnet width to be equal to or more than the variable range of the plate width, electrical control of causing the magnet to follow the plate edge becomes unnecessary. Therefore, the apparatus becomes very simple and a large investment can be reduced.

In this embodiment, a single magnet consisting of an N-pole and an S-pole is arranged in the horizontal direction up to the upper and lower ends of both ends over the width of the steel plate. However, the present invention is not limited to this. However, as shown in FIG.
1, a split type in which the magnets M1 to M4 are arranged only in the upper and lower portions P1 and P2 of C2.

Next, another embodiment of the present invention will be described.
As shown in FIG. 6, the meandering prevention device vertically separates the magnets M1a to M4a having N poles and S poles into both ends C of the steel sheet P.
1 and C2, the upper and lower portions P1 and P2 are fixed so that the same poles face each other. In the present embodiment, the magnets M1a and M2a are configured such that the N poles face each other, and the magnets M3a and M4a are configured so that the S poles face each other. The poles may be used, or the magnetic poles facing the magnets M3a and M4a may be used as N poles. Further, in the present invention, the magnets M1a to M4a may be of a split type as shown in FIG. 7 when the same poles of the upper and lower magnets are opposed to each other. it can. The gap G between the magnets shown in FIG. 7 can be omitted when a large attractive force is required. It is to be noted that 1 is preferably made of a ferromagnetic material or a plate magnet, since a high magnetic flux density can be obtained.

The arrangement of the magnets with respect to the steel plate P can be appropriately selected. In the case of the separation magnet shown in FIG. 6, when the steel plate P moves in the Y direction as shown in FIGS. Since the attraction force increases and the restoring force acts, the tip Pa of the steel sheet P is moved from the side ends of the magnets M1a and M2a to each magnet M
The point at which 1 / 4h of the width dimension h of 1a and M2a is inserted and the magnet M1
a, M2a is to be located approximately between the centers. At this time, the width dimension h required for the magnets M1a to M4a
Is the maximum width and the minimum width of the width H of the steel sheet P as Mmax and Mmin, and the allowable meandering amount of the steel sheet P is α, as shown in the following equation (9), The length is about four times the length obtained by adding the allowable meandering amount α of the steel sheet to ２ of the large Hmax−the minimum width Hmin). In addition, in anticipation of stability against sudden meandering, α in Expression (9) is set to 2α
It is desirable that

[0028]

(Equation 6)

On the other hand, in the case of the split type magnet shown in FIG. 7, as shown in FIGS. 9 and 10, the tip Pa of the steel plate P comes near the center of the N pole in the width direction of the magnets M1a to M4a. To do. At this time, the length h1 of the magnets M1a to M4a in the width direction outside the plate path is equal to or larger than the allowable meandering amount α, preferably 1.5α to 2α, and the length h2 in the width direction in the plate path is As shown in Expression (10), the length is required to be about three times the length obtained by adding the allowable meandering amount α to １ ／ of (the maximum width Hmax−the minimum width Hmin) of the steel sheet P. It should be noted that α is preferably set to 2α in the expression (10) in consideration of stability against sudden meandering.

[0030]

(Equation 7)

The above description is for the case where the magnets are fixedly arranged. However, when the width of the steel plate to be passed is changed, the magnets are moved and the positional relationship between the magnets and the steel plate is adjusted to the optimum position as described above. Preset as follows. The movement of the magnet
Automatically using a motor or the like by inputting the width of the steel plate or detecting the width using a sensor. By providing such a preset device, the width of the magnet can be reduced. Whether the magnet is always fixedly arranged or preset by changing the width of the steel plate is determined based on a change range of the plate width, an installation space, and the like. Further, in the present invention, the magnets in the upper and lower portions are configured so that the same poles face each other, so that almost no attractive force to the steel sheet is generated, but still, due to a decrease in the line tension of the steel sheet, the weight of the steel sheet is reduced. If there is a risk of contact with the magnet, contact between the steel plate and the magnet can be easily prevented by installing support rolls before and after the magnet.

Next, the meandering preventing device of the present invention will be described based on embodiments, but the present invention is not limited to only such embodiments.

Example 1 As shown in FIG. 7, a permanent magnet (2000 to 2500 gauss) having a width of 300 mm and a length of 300 mm is provided on both sides of a steel sheet P.
Are fixed in such a manner that the same poles are opposed to each other by sandwiching the steel plates P, and a steel plate P having a thickness of 0.5 mm and a width of 1100 mm is subjected to a line tension of 1.5 kg / mm ² and a line speed of 1 mm.
The sheet was passed at 00 m / min.

Next, the steel plate was forcibly meandered 20 mm in both the left and right directions on the entry side of the device. After passing through the meandering prevention device, the center passing can be stably performed with a meandering amount of about ± 1 mm. Was. Further, from the middle, the board width is set to 1000 mm.
However, it was possible to pass through without any meandering, even during transitions. In addition, no adsorption of the steel plate to the magnet occurred.

The same effect was obtained with a steel plate having a thickness of 0.1 mm or 2 mm, but the same effect was obtained irrespective of the thickness.

Comparative Example 1 The same steel plate as in Example 1 was forcibly meandered by 20 mm in both the left and right directions on a line without using the meandering prevention device.
The sheet was passed while the meandering amount was ± 20 mm.

From the results of Example 1 and Comparative Example 1, Example 1
As described in the above, the meandering of the steel sheet could be prevented by using the meandering prevention device in the feeding path of the steel sheet.

[0038]

As described above, according to the present invention,
By arranging the magnets above and below the steel sheet so that the same poles face each other so that a repulsive force acts between the magnets, the magnet and the steel sheet do not adhere to each other without electrical control. It can be passed through ± 1 mm. As a result, the capital investment can be reduced, and the reliability of meandering prevention can be improved.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing one embodiment of a meandering preventing device for a steel sheet according to the present invention.

FIG. 2 is an explanatory diagram of a pressure acting on a magnetic field.

FIG. 3 is a diagram illustrating the operation of the meandering prevention device in FIG. 1;

FIG. 4 is a diagram for explaining the operation of the meandering prevention device in FIG. 1;

FIG. 5 is an explanatory view showing another arrangement of the magnet in FIG. 1;

FIG. 6 is an explanatory view showing another embodiment of the present invention.

FIG. 7 is an explanatory diagram showing another arrangement of the magnets in FIG. 6;

FIG. 8 is an explanatory diagram showing an arrangement relationship between a magnet and a steel plate in FIG. 6;

FIG. 9 is an explanatory diagram showing an arrangement relationship between a magnet and a steel plate in FIG. 7;

FIG. 10 is a schematic diagram showing the attraction force of the magnet in FIGS.

[Explanation of symbols]

C1, C2 end M1, M2, M3, M4, M1a, M2a, M3a, M
4a Magnet P Steel plate P1 Upper part P2 Lower part

Claims (2)

[Claims] 1. A meandering preventing device for preventing meandering of a strip-shaped steel sheet that is continuously passed, wherein a magnet having the same polarity faces at least upper and lower portions at both ends in a width direction of the steel sheet. A meandering preventing device for a steel plate, which is arranged. 2. The meandering prevention device according to claim 1, wherein the magnet is movable in accordance with a width of the steel plate.