JPH06182419A - Controller for preventing rolling-down cylinder of rolling mill from sinking - Google Patents

Abstract

PURPOSE:To provide a controller to prevent the rolling down cylinder of a rolling mill from being sunk, to reduce an absolute sunk amount generated in a rolling down cylinder and to prevent the gage failure, passing failure of a sheet from occurring. CONSTITUTION:In the control of the sheet thickness in the rolling mill 1, a pull back controlling part 21 is provided wherein according to each signal of metal off, metal bite in of the rolling mill 1 detected by a load cell 6 built in the rolling mill 1, an oil column on the head side of the rolling down cylinder 5 is controlled under the metal off state, hydraulic force in a range of a fixed pressure is energized to a stationary cylinder rod side and hydraulic pressure on the side of the cylinder rod is dissolved at a fixed time after the metal is bitten in.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling-cylinder sinking prevention control device for a rolling mill, and is particularly useful when applied to a case where the rolling-down cylinder is prevented from sinking when the threaded plate is caught in the work roll gap. It is a thing.

[0002]

2. Description of the Related Art A steel rolling mill controls a gap 03 between upper and lower rolling rolls 01 and 02 with a hydraulic cylinder 04 or the like as schematically shown in FIG. 5 to roll a plate 05 having a target thickness. To do. Now, the roll gap 0 shown in FIG.
When the plate 05 to be rolled into No. 3 bites at high speed as shown in FIG. 5 (b), the impact causes the hydraulic oil 04a in the cylinder 04.
Is compressed and cylinder 0 is opened in the direction that roll gap 03 opens.
A subduction 06 phenomenon occurs in which 4 is displaced. The subsidence 06 is recovered by the automatic control function of the control device for holding the oil column, and recovers within a predetermined time, and enters a rolling state with a normal roll gap as shown in FIG. 5 (c). As a result, the defective gauge portion 0 having a different thickness is attached to the tip of the plate 05.
5'is generated, which causes a threading failure in the next rolling roll section.

The amount of depression 06 of the hydraulic cylinder 04 varies depending on the type of working oil, the pressure, the initial volume of oil in the cylinder, and the like. In a rolling mill in which the rolling screw is omitted and the gap between rolls is adjusted by cylinder operation, a long oil column cylinder with a long cylinder stroke is used, so the amount of subduction increases, causing an abnormality.

FIG. 6 is an explanatory view showing a conventional technique for preventing the occurrence of a gauge defect at the tip of the plate 05 due to the depression of the cylinder as described above. In this prior art, as shown in FIG. 6A, the height of the oil column of the hydraulic cylinder 04 is set to be large so as to reduce the roll gap 03 of the rolling mill by a predicted subduction amount of 06 minutes. As shown in FIG. 6 (b), after the plate 05 is bitten, by controlling the change to the regular oil column height l ₁ within a certain time, it is possible to suppress the occurrence of gauge failure as shown in FIG. 6 (c). is there.

[0005]

The prior art shown in FIG. 6 is effective for a rolling mill with a small subduction amount, but in the case of a rolling mill using a rolling cylinder with a long oil column, the rolling screw is omitted. As the amount of subsidence of the cylinder increases, the remaining gap that is initially adjusted becomes closer to zero, and there is a difference in the amount of subsidence between the drive side DS and the work side WS of the work roll. However, there is a problem such as a defective threading and a defective gauge.

In contrast to the above-mentioned conventional problems, the present invention reduces the absolute amount of subsidence that occurs in the reduction cylinder, and thereby reduces the gauge of the strip and the reduction of the rolling of the rolling mill. An object of the present invention is to provide a cylinder sinking prevention control device.

[0007]

Means for Solving the Problems The structure of the present invention for achieving the above object has a reduction cylinder for reducing a work roll of a rolling mill toward a plate which is a material to be rolled by the work roll. A rolling cylinder rolling-down cylinder sinking prevention control device configured to hold the head-side oil column, which is the plate side of the rolling-down cylinder, in a state in which no plate exists between the work rolls. A load cell that detects each state of metal entrapment, which is a state in which the plate is caught between work rolls, and a cylinder rod that is the side opposite to the plate of the reduction cylinder when a metal-off state is detected by the load cell. Side is applied with a predetermined hydraulic pressure, and the cylinder lock of the reduction cylinder is set for a certain period of time after the load cell detects the metal engagement state. And having a pull-back control unit to release the oil pressure side.

[0008]

According to the present invention having the above-mentioned structure, at the time of starting the rolling operation, the head side oil column height of the reduction cylinder is controlled at the time of the initial gap adjustment, and at the same time, the rod side oil chamber is biased with a certain range of oil pressure in the metal-off state. To do. This hydraulic pressure on the rod side acts as a reaction force to the cylinder head side, increasing the hydraulic pressure on the cylinder head side, suppressing hydraulic rolling in the cylinder when the plate is caught in the roll gap, and reducing the sinking of the cylinder. Let The hydraulic pressure on the rod side is opened for a certain period of time immediately after the plate is bitten, and when the pullback is opened to release the pressure, the oil pressure in the oil chamber on the cylinder head side is reduced, which offsets the pressure increase due to biting and prevents fluctuations in the roll gap. It

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a block diagram schematically showing the configuration of an embodiment of the present invention. As shown in FIG. 1, the rolling mill 1 includes work rolls 3 a and 3 b, backup rolls 4 a and 4 b, a hydraulic pressure reduction cylinder 5 and a load cell 6 in a housing 2. The plate 7 is rolled between the work rolls 3a and 3b. The hydraulic circuits 8 and 9 are connected from the hydraulic pump 10 to the head side and rod side (pullback side) of the hydraulic pressure reduction cylinder 5.
Leading to. The rod side circuit 9 is hereinafter referred to as a pullback circuit.

In the figure, 11 is a servo valve provided on the hydraulic circuit 8, 12 and 13 are pressure reducing valves and electromagnetic switching valves provided on the pullback hydraulic circuit 9, and 14 is an oil column height detection attached to the pressure reducing cylinder 5. Reference numeral 15 is a control device for controlling the reduction cylinder 5.

The control device 15 comprises an oil column target value transmission unit 16, a reference flow rate gain calculation unit 17, an addition unit 18, an integration unit 19, a converter 20 and a pullback control unit 21. The oil column height detector 14 inputs the detected oil column height signal to the adding section 18 via the signal line 22, and the load cell 6 is set to the work roll 3
The metal-off state in which the plate 7 does not exist between a and 3b and the metal-engaged state in which the tip of the plate 7 enters between the work rolls 3a and 3b are detected, and the metal-off signal is sent to the pullback control unit 21 via the signal line 23. And a metal biting signal.

In the reference flow rate gain calculation unit 17, since the flow rate characteristic of the servo valve 11 changes depending on the load, the servo valve 1
The optimum flow rate gain that matches the flow rate characteristic of 1 is calculated by a preset reference value. The flow rate gain calculated by the reference flow rate gain calculating section 17 is integrated into the oil column target value signal by the integrating section 19, and the servo valve 11 is passed through the converter 20.
Is controlled to adjust the head side pressure oil amount of the pressure reduction cylinder 5, and the actual oil column height signal from the oil column height detector 14 is
It is fed back to the adder 18 and is controlled so that the oil column height reaches the target value.

On the other hand, in accordance with the head side oil column height control of the reduction cylinder 5, the pullback control section 21 responds to the input signal from the load cell 6 and the pressure reducing valve 12 makes a constant range when the rolling mill 1 is in the metal-off state. Solenoid valve 1 for pressure oil depressurized to
3 to feed the pressure to the rod side of the pressure-reducing cylinder 5 to bias the hydraulic pressure, and when the metal is engaged, the head side servo valve 11
The control of the solenoid valve 13 on the rod side, that is, the pullback side is performed so that the hydraulic pressure on the rod side is released within the response speed time. The hydraulic pressure on the head side and the rod side of the reduction cylinder 5 used in this control is, for example, 300 kgf on the head side.
/ Cm ² , the rod side is about 70 to 80 kgf / cm ² .

FIG. 2 schematically shows the hydraulic circuit of the above device. Two hydraulic pressure reduction cylinders 5 are provided symmetrically in a pair in the housing 2 of the drive side DS and the work side WS of the rolling mill 1, and branch from the pump 10 to reduce the pressure reduction cylinders 5.
Servo valves 11 and 11 are provided on the circuits 8 and 8 connected to the head side of 5, respectively, and the pressure is reduced on one pullback circuit 9 that is branched from the pump 10 and connected to the rod sides of the two reduction cylinders 5 and 5. A valve 12 and a solenoid valve 13 are provided.

In the figure, 25 is a relief valve on the pullback circuit 9 side, 26 is a servo valve 11, 11, a solenoid valve 13 and a pressure oil return pipe from the relief valve 25 to the tank 26,
The servo valves 11, 11 and the solenoid valve 13 are controlled and operated by the control signal from the control device 15 as described above.

FIG. 3 is an explanatory view of a rolling state corresponding to the prior art of FIG. 6 in the above-described embodiment of the present invention, and FIG. 4 is FIG.
3 is a control flow of the apparatus.

The operation of the apparatus will be described with reference to FIGS. 3 and 4. When the control device 15 starts controlling the reduction cylinders 5 and 5, the rolling mill 1 is initially in the metal-off state, the load-cell 6 detects the metal-off, and a signal is input to the pullback control unit 21. The oil column target value transmission unit 16 and the reference flow rate gain calculation unit 17 perform automatic oil column control on the reduction cylinder head side via the servo valve 11 and
At the same time, the hydraulic pressure of the set pressure is applied to the pressure reducing cylinder rod side via the pullback control unit 21 and the solenoid valve 13. FIG. 3A shows the state at this time, and [pullback ON] on the rod side of the cylinder 5 shows a state in which hydraulic pressure is applied to the rod side. Next, as shown in FIG. 3B, when the load cell 6 detects that the plate 7 is caught between the rolls 3a and 3b, the pullback control unit 21 does not respond for a certain period of time, for example, the servo valve 11 on the cylinder head side. Within a period of time, the solenoid valve 13 is switched, the hydraulic pressure on the cylinder rod side [pullback ON] is released, and the hydraulic pressure is released [pullback OF.
F]. At this time, the initial impact of the plate 7 is
The pressure applied on the cylinder rod side is backed up, and the high rolling and high pressure hydraulic pressure on the cylinder head side oppose each other, so that the depression of the rolling down cylinder 5 due to rolling is reduced. At this time, the pressure in the oil chamber on the cylinder head side increases due to the biting impact, and the servo valve 11 works to reduce the oil amount by the automatic adjustment of the control device. When the pressing pressure is released, the stroke fluctuation of the reduction cylinder 5 is canceled and the steady rolling operation state is entered. As a result, FIG. 3 (a), (b),
As shown in (c), the depression of the pressing cylinder 5 when the plate is engaged is greatly reduced, and the oil column height l ₁ is kept constant.
The defective gauge [05 'in FIG. 5 (c)] at the tip of the can also be eliminated.

As the rolling progresses, the rolling mill 1 is driven by the load cell 6.
When the metal off is detected, when the rolling is continued, the operation is repeated in the same cycle by returning to the cylinder head side and rod side oil column control and pressure control again.

Therefore, according to the above-mentioned device, the long oil column,
Even in a rolling mill that uses a long-stroke reduction cylinder, or when using a short oil column or a short-stroke reduction cylinder, the depression of the reduction cylinder 5 due to the impact at the time of biting the plate 7 to be uniformly rolled Also, it is possible to solve the problems of gauge failure and threading failure.

The configurations of the elements of the control unit and the pullback circuit unit in the present invention are not limited to the above-mentioned embodiments, and various design changes can be made within the scope of the present invention.

[0022]

As described above in detail with reference to the embodiments, according to the present invention, in the plate thickness control of the rolling mill, the metal turning-off and the metal turning-off are detected according to the signals of the metal turning off and the metal biting of the rolling mill detected by the load cell. In addition to the control of the head side oil column of the pressure reduction cylinder under the above conditions, a pull back control unit that constantly urges a certain range of oil pressure to the cylinder rod side and releases the cylinder rod side oil pressure within a certain time after the metal is caught. As a result, regardless of the length of the reduction cylinder used in the rolling mill, the pressurization backup on the pullback side is uniformly used to reduce or prevent the depression of the reduction cylinder when the plate is engaged, and prevent gauge defects during rolling. It has the effect of significantly improving threading failure.

[Brief description of drawings]

FIG. 1 is a block diagram schematically showing a configuration of an exemplary embodiment of the present invention.

FIG. 2 is a circuit diagram showing a hydraulic circuit of the above embodiment.

FIG. 3 is an explanatory view showing a mode at the time of rolling in the above embodiment.

FIG. 4 is a flowchart showing the operation of the above embodiment.

FIG. 5 is an explanatory view showing an aspect at the time of rolling in the prior art.

FIG. 6 is an explanatory diagram showing a mode during rolling in another conventional technique.

[Explanation of symbols]

 1 Rolling mill 3a, 3b Work roll 5 Rolling cylinder 6 Load cell 7 Plate 21 Pullback control unit

Claims (1)

[Claims] 1. A rolling machine having a work roll of a rolling mill, which has a reduction cylinder for reducing the work roll toward a plate which is a material to be rolled, and a constant oil column on the head side which is the plate side of the reduction cylinder. A rolling-down cylinder depression prevention control device for a rolling mill configured to hold a metal-off state in which no plate is present between the work rolls and a metal engagement state in which the plate is engaged between the work rolls. The load cell that detects each of the jamming states, and when a metal-off state is detected by the load cell, applies a predetermined hydraulic pressure to the cylinder rod side, which is the side opposite to the plate of the reduction cylinder, and causes the metal mesh by the load cell. And a pullback control unit for releasing the hydraulic pressure on the cylinder rod side of the reduction cylinder within a certain period of time after the jamming state is detected. Prevention control device sinking down cylinder of the rolling mill, characterized in that.