JPH08224617A - Tension leveler - Google Patents

Abstract

PURPOSE: To suppress the vibration of a material to be straightened, to improve the quality of a product by preventing the occurrence of a chatter mark on a strip, at the same time, to enable working in a high speed range, and to improve productivity in a tension leveler for straightening a steel sheet with ferromagnetism. CONSTITUTION: Plural magnets 9 are arranged in the width direction of a strip between a pair of work rolls 2 and a deflector roll 5 installed on the downstream side in the transfer direction of a material (strip) 1 to be straightened. Position detectors 6 are installed respectively so that a pair of the position detector 6 and the magnet 9 is made. Lagging filter and band pass filter are used in series as control circuits controlling the magnets 9 respectively by feeding back a signal from the position detector 6. The center frequency of the band pass filter is individually changed near the primary natural frequency of the material 1 to be straightened between the work roll 2 and the deflector roll 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tension leveler for straightening a steel sheet having ferromagnetism.

[0002]

2. Description of the Related Art Generally, when a strip of cold-rolled steel plate, stainless steel plate, aluminum plate, etc. is rolled by a rolling mill, the rolling process causes warping, partial elongation, and distortion of the strip. A tension leveler is used to do this.

FIG. 4 schematically shows a conventional tension leveler. As shown in FIG. 4, work rolls 2 are arranged on the upper and lower sides of the pass line of the strip 1 in front of and behind the strip 1 in the conveying direction.
A deflector roll 5 is disposed downstream of the deflector roll 5.

Behind the work roll 2 which directly presses the strip 1, there are two intermediate rolls 3 which receive a reaction force applied to the work roll 2 and a backup roll 4 which receives a reaction force applied to the intermediate roll 3. ing. Although not shown, generally, a plurality of such tension levelers are appropriately provided.

A rotatable roller 10 is attached to the surface of the strip 1 by a spring 11 so as to have a predetermined surface pressure, and a vibration damping device 12 is attached to the roller 10 in its moving direction. ing. The vibration damping device 12 suppresses the vibration of the strip 1.

The purpose of mounting the vibration damping device 12 is as follows.

If the vibration damping device 12 is not provided, when the strip passing speed of the strip 1 is increased, a line-like very faint cloud called a chatter mark may occur on the surface of the strip 1.

FIG. 5 shows a strip having chatter marks. As shown in FIG. 5, the chatter mark P is generated like a striped pattern intermittently along the direction orthogonal to the transport direction of the strip 1 (the direction of the arrow in the figure). It is considered that the chatter mark P is generated due to self-excited vibration of the strip 1 between the roll pitches on the downstream side with the work roll 2 as a fulcrum.

FIG. 6 shows an outline of a tension leveler showing the vibration state of the strip, and FIG. 7 shows a graph showing the amplitude of the strip.

As shown in FIG. 6, for example, paying attention to the strip 1 between the work roll 2 and the deflector roll 5, when the transport speed of the strip 1 is slow, as shown by the solid line in FIG. Strip 1 passes over the pass line.

However, when the transport speed of the strip 1 is high to some extent, the strip 1 vibrates above and below the pass line as shown by the chain double-dashed line in FIG.

When the transport speed of the strip 1 is low, as shown in FIG. 7 (a), even if the strip 1 vibrates due to disturbance, the vibration is gradually attenuated.

However, when the transport speed of the strip 1 is high to some extent, the strip 1 naturally vibrates as shown in FIG. There is no attenuation unless the transport speed of is reduced.

When the vibration of the strip 1 continues in this way, it is plastically worked in the contact portion with the work roll 2 and this changes depending on the frequency of vibration, so that the chatter mark P is generated on the surface of the strip 1 as described above. Resulting in.

Therefore, the vibration damping device 12 prevents vibration of the strip 1 and eliminates the occurrence of chatter marks.

Although the mechanical damping device in the tension leveler has been described above, there is a general damping system shown in FIG. 8 for damping the strip.

That is, in the vibration damping device for the strip shown in FIG. 8, the position of the strip 1 is detected by the position detector 6, and the signal is used to control the electromagnet 9 through the control circuit 7 and the drive circuit 8 so that the strip 1 is constantly operated. It is the same position.

The control circuit uses signal processing such as proportional, differential, and integral to secure a certain frequency range in which damping is desired. Basically, a plurality of electromagnets in the width direction of the strip are used. On the other hand, all tunings are the same.

[0019]

By the way, as described above, in the conventional mechanical strip attenuator in the tension leveler, since the roller is in contact with the strip, the strip is easily scratched, which causes a problem in product quality. There was also a problem with the durability of the roller.

Regarding the vibration damping device using the electromagnet,
There is a problem that the control circuit is expensive.

An object of the present invention is to provide a new tension leveler that solves these problems.

[0022]

As a structure for achieving the above object, a tension leveler of the present invention comprises a pair of works from both sides in the plate thickness direction on a ferromagnetic material to be straightened which is conveyed while being given a tension. In the tension leveler of the method of correcting the material to be corrected by pressing the roll, an electromagnet is provided between the pair of work rolls and the deflector roll arranged on the downstream side in the transport direction of the material to be corrected. A plurality of position detectors are arranged in the width direction of the material to be straightened, and a position detector is installed so as to be paired with the member to be corrected, and a phase delay is provided as a control circuit for feeding back a signal from the position detector to control each of the electromagnets. The filter and the band pass filter are connected in series, and the center frequency of the band pass filter is controlled individually near the primary natural frequency of the material to be straightened between the work roll and the deflector roll. It is characterized by being configured to vary.

[0023]

According to the tension leveler of the present invention configured as described above, the vibration of the material to be straightened generated at a certain speed or more is applied in a non-contact manner in the vicinity of the primary natural frequency of the strip so that the vibration is suppressed. Occurrence can be suppressed.

As a result, it is possible to prevent the occurrence of chatter marks on the strip and improve the product quality, and it is possible to operate in a high-speed region to improve the productivity, and further wear and the like. It is possible to provide a tension leveler that is excellent in durability and does not generate.

The frequency of this vibration varies to some extent depending on the material and the correction conditions, but by using a lag filter and a bandpass filter in series as a control circuit, the control circuit can be made inexpensive, and Since the center frequency of the band pass filter of the control circuit is slightly changed for each circuit in the vicinity of the first-order natural frequency of the strip, the damping force can always be applied within the change range of the vibration frequency, and It is possible to cope with changes in natural frequency due to different conditions.

[0026]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a schematic view showing a tension leveler according to an embodiment of the present invention, (a) is a plan view and (b) is a side view.

In the figure, work rolls 2 are provided on both upper and lower sides of a pass line of a strip 1 as a material to be straightened, an intermediate roll 3 is provided behind the work roll 2, and a backup is provided behind it. A roll 4 is provided to enhance the rigidity of the work roll 2.

A deflector roll 5 is arranged on the downstream side of the work roll 2, and the strip 1 is composed of the work roll 2,
The plate is passed while being in contact with the deflector roll 5.

Between the work roll 2 and the deflector roll 5, a plurality of electromagnets 9 are arranged in close proximity to each other in the width direction of the strip 1. A position detector 6 for detecting the position is arranged. The electromagnet 9 is driven by the drive circuit 8 via the control circuit 7 by the signal of the position detector 6.

FIG. 2 shows an example of the control circuit 7, in which a lag filter and a band pass filter are used in series. Further, as shown in FIG. 3, the center frequency f _n of the band pass filter is individually changed for each control circuit so that the phase lead frequency region is widened to some extent.

The reason for such a configuration is as follows. That is, the frequency of the normal chatter mark substantially matches the natural frequency of the strips of the work roll 2 and the deflector roll 5, and is given by the following equation.

[0032]

[Equation 1] Where l: roll pitch (distance between work roll and deflector roll) σ: unit tension ρ: strip density

However, this frequency changes to some extent depending on the material of the strip in operation and the correction conditions.

The center frequency f _n of the band pass filter is individually tuned so that the entire range of change in natural frequency falls within the phase lead frequency region.

By thus tuning, it is possible to always apply a damping force to the vibration of the strip 1.

Although one embodiment of the present invention has been briefly described below, the present invention is not limited to the above embodiment and various design changes can be made within the scope of the technical idea of the present invention. It belongs to the technical scope of the invention.

[0037]

According to the tension leveler of the present invention, it is possible to suppress the vibration of the material to be straightened, prevent the occurrence of chatter marks on the strip, improve the product quality, and operate in the high speed range. Therefore, it is possible to improve productivity, and it is possible to provide a tension leveler that is excellent in durability without causing wear or the like.

Further, the control circuit can be made inexpensive, and the center frequency of the bandpass filter is slightly changed for each circuit in the vicinity of the first-order natural frequency of the strip. It is possible to respond to changes in frequency.

[Brief description of drawings]

FIG. 1 is a schematic view of a tension leveler according to an embodiment of the present invention, (a) is a plan view and (b) is a side view.

FIG. 2 is a control circuit diagram in the apparatus of FIG.

FIG. 3 is a control system diagram of the device.

FIG. 4 is a schematic side view of a conventional tension leveler.

5A and 5B are schematic views of a strip in which a chatter mark is generated, FIG. 5A is a plan view, and FIG. 5B is a side view.

FIG. 6 is a schematic view of a tension leveler showing a vibration state of a strip.

7 (a) and 7 (b) are graphs showing the amplitude of a strip.

FIG. 8 is a schematic view showing a vibration damping device for a strip generally proposed.

[Explanation of symbols]

 1 strip (material to be straightened) 2 work roll 3 intermediate roll 4 backup roll 5 deflector roll 6 position detector 7 control circuit 8 drive circuit 9 electromagnet

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Minji Fujimoto 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima City Mitsubishi Heavy Industries Ltd. Hiroshima Works

Claims (1)

[Claims] 1. A tension leveler that corrects the material to be straightened by pressing a pair of work rolls from both sides in the plate thickness direction to the material to be straightened, which is conveyed by applying a tension, Between the pair of work rolls and the deflector roll arranged on the downstream side in the conveying direction of the material to be corrected, a plurality of electromagnets are arranged in the width direction of the material to be corrected,
And a position detector is installed so as to be paired with it, and a delay filter and a bandpass filter are connected in series as a control circuit for feeding back a signal from the position detector to control each of the electromagnets, and A tension leveler, wherein the center frequency of the band pass filter is changed for each control circuit in the vicinity of the primary natural frequency of the material to be straightened between the work roll and the deflector roll.