KR200268636Y1 - A Device For Preventing Failure In An Automatic Gauge Control Work-Roller Of A Rolling Machine - Google Patents

Abstract

The present invention relates to a malfunction prevention device of an AGC work roller of a continuous two-roller rolling mill device. In addition to a position sensor attached to an AGC cylinder, a hydraulic pressure sensor included in a servo valve can be installed and a feedback value can be selected as necessary. AGC, which supplies stable hydraulic pressure to AGC cylinders by quickly modifying feedback control values when there is a risk of malfunction in AGC work rollers or AGC cylinders by using the hydraulic pressure values from the oil pressure sensor when control instability factors and phenomena are detected. It is a malfunction prevention device of work roller. According to the present invention, it is possible to quickly detect and control abnormalities often occurring between the servovalve and the AGC cylinder to detect equipment troubles caused by the control instability of the system at an early stage and stabilize them before entering the instability state. Production quality and equipment operation efficiency can be improved.

Description

A Device For Preventing Failure In An Automatic Gauge Control Work-Roller Of A Rolling Machine}

The present invention relates to a malfunction prevention device of an AGC work roller of a continuous two-roller rolling mill device, and more specifically, to an AGC work by using a hydraulic value from a hydraulic pressure sensor included in a servo valve in addition to a position sensor attached to an AGC cylinder. The present invention relates to a malfunction prevention device for an AGC working roller that provides stable hydraulic pressure to an AGC cylinder by quickly modifying a feedback control value when there is a risk of malfunction of a roller or an AGC cylinder.

In general, the rolling mill, which is a main equipment of a steel production and manufacturing company, is composed of a pair of upper work rollers and a lower work roller which are driven by an electric motor facing each other up and down on a mill stand, between the upper work roller and the lower work roller. It has the structure and working principle of rolling mill type that continuously rolls while passing the rolling material under appropriate pressure.

Figure 1 shows the overall configuration of a conventional rolling mill AGC working roller device and AGC working roller malfunction prevention device.

The upper work roller 28-2 is installed at the upper part of the rolling mill housing, is fixed to the screw down and the balance cylinder at the upper side of the housing, and can move up and down within a certain section. While looking at the position movement gauge of the screw down, the upper work roller is moved up and down to check the working position and fix the upper work roller. At this time, the rolling load of the working roller can be seen by the load cell 29 in the pressure block of the screw down. The lower work roller 28-1 is installed at the lower part of the rolling mill housing and is located above the AGC (Automatic Gauge Control) cylinder. In order to control the position of the how work roll, it is controlled through a position sensor (or MP scale) 27 mounted to the AGC cylinder moving up and down in proportion to the movement value of the lower work roll. The MP scale including the position sensor converts the mechanical position change into an electrical signal through a control loop and feeds the signal back to the control means 36. The control means according to the difference between the input reference value set value and Compensate the error value and input it to the servovalve 40.

The servo valve 40 supplies the hydraulic pressure as needed through the control port 22 connected to the AGC cylinder 26 by adjusting the valve by the torque motor according to the compensation signal input from the control means 36 to supply the AGC cylinder. Move up and down. Through this process, the gap (GAP) between the lower work roller mounted on the AGC cylinder and the upper work roller installed on the upper of the rolling mill housing is automatically controlled to pass the hot rolled product 28-3 therethrough. It is possible to carry out a continuous rolling operation while maintaining a constant thickness according to. As described above, the servo valve 40 controls the oil pressure and flow rate of oil supplied to the AGC cylinder proportionally and precisely according to the magnitude of the electric input signal received from the servo valve control means 36. It is manufactured to be used for automatic control of continuous rolling operations.

The automatic principle of the servovalve is as follows. First, when the user sets the servovalve reference value, the servovalve starts to operate, such as specifying the required position of the AGC cylinder or the vertical position of the work roller below the rolling mill. When the servo valve starts to operate, the position control system 27 of the actuator (AGC cylinder 26) inputs the current position data to the comparison differential controller 34. In the comparison differential controller 34, the servo valve set by the user is set. The reference value and the feedback value are compared, and according to the error, the servovalve operation controller 35 sends a compensated input current proportional to the error value to the coil 3 of the servovalve. When this input current flows in the servovalve coil 3, magnetic polarity is generated in the armature 7, and the armature 7 is inclined in proportion to the magnitude and polarity of the current. As a result, the gap between the flapper 1 located in the middle of the armature 7 and the nozzle 2 changes according to the inclination of the armature 7. The back pressure on the side where the gap between the left and right nozzles 2 is narrower rises than on the wide side, and the change in the back pressure between the left and right nozzles 2 is caused by the left and right end flow paths 11 and 12. To make a difference in back pressure.

At this time, when the input current flows to the right coil 3 of the servovalve, the armature 7 inclines to the right and the back pressure increases as the gap between the right nozzle and the flapper is narrowed. The pressure of the right end flow passage 12 of this spool is greater than the pressure of the left end flow passage 11 of the spool, and the force on the right of which the pressure is increased pushes the spool 15 to the left, and thus the main pressure supplied from the pump The supply pressure in the port 23 flows to the C2 port 22. By this hydraulic pressure, the C2 port flow path supplies the AGC cylinder 26 with the required pressure and flow rate to move the AGC cylinder 26 and the lower work roller 28-1 directly or indirectly connected thereto to move upward. do.

Contrary to the above, when the armature 7 is pulled to the left by the input current from the servovalve control means, the gap between the left nozzle and the flapper is narrowed to increase the back pressure, and the pressure of the left end flow path 11 of the spool is increased. This increase pushes the spool 15 to the right, the oil in the C2 port 22 is discharged to the return port 24 and the repulsive force proportional to the volume and hydraulic pressure of the discharged oil acts to actuate the piston of the AGC cylinder 26. The lower work roller 28-1 is lowered downward as much as the vertical downward direction.

In other words, the position (servo valve reference value) and feedback value of the work roller set by the user are viewed as inputs, and the servo valve operation and the vertical movement position of the piston in the AGC cylinder are output as follows.

Input Reference Value (33) ± Feedback Value (Comparative Differential Controller; 34)

= Current value for servo valve operation control

By vertically moving the piston of the AGC cylinder 26 by the control loop as described above, the position control of the lower work roller 28-1 is performed, thereby enabling continuous rolling operation.

However, during the continuous operation, the position of the AGC cylinder (or lower work roller) may be different from the servo valve reference value set by the user due to various factors. There have been many cases of delays due to frequent delays. That is, in the conventional rolling mill AGC work roller malfunction prevention system, the fluid used as the channel between the AGC cylinder 26 and the servovalve 40 is always pulsation of the fluid itself due to the organic problems of the system. The disturbance caused by this is extremely short and extinguished in the system, and in some cases causes the system to become unstable. The causes of such instability and its abnormalities are plotted as follows.

Outbreak factor Causes Anomaly Control factor Over current, transient response, disturbance, noise, poor control, unstable control, offset too large Excessive opening due to malfunction, TMA coil damage, Roll Nec break, Plate breaking, Rolling impossible, Poor quality, etc. Hydraulic factors Cylinder Resonance, Hydraulic System Oil Contamination, Pick Pressure Hunting, Inner Cylinder Leakage Malfunction, plate breaking, too fast opening, poor rolling quality, no rolling, loss of roll neck Servovalve factor Servo valve abnormal wear, operation delay, characteristic change, servo valve failure, ball flat, TMA coil burn out, spool stick No rolling, malfunction, plate breaking, too fast opening, poor rolling quality

When such an abnormality occurs, in the position control system, the position feedback value after the piston of the AGC cylinder 26 is vertically moved is not quickly compensated for by the control, and is transmitted directly to the AGC cylinder, thereby directly transmitting the AGC cylinder 26. The processing time is slower than the direct processing of the pressure control signal generated between the servo valve 40 and the servo valve 40, or an inoperable state occurs. Thus, the gap control between the upper and lower work rollers becomes unstable. It is happening frequently. If such control instability occurs, the servovalve will go beyond the normal operating range and cause the rolling system to malfunction, which directly affects production and quality, such as miss roll, plate breaking, roll neck loss, etc. The problem with the prior art was that there was always a risk of equipment failure and pressure regulation.

The present invention is devised to solve the problems of the above-described unstable rolling mill system, and provides an apparatus for preventing system instability by quickly detecting a momentary instability factor and phenomenon that may occur between the AGC cylinder and the servovalve. It aims to do it.

In addition, the present invention improves the equipment operating efficiency of the rolling mill AGC system by detecting abnormal phenomena between the AGC cylinder and the servovalve, and produces a rolled product that passes through the AGC cylinder as a feedback input. It aims to improve the quality.

Figure 1 is a schematic diagram showing the configuration of a conventional rolling mill AGC work roller malfunction prevention device in the field of the present invention,

Figure 2 is a schematic diagram showing the configuration of the improved rolling mill AGC work roller malfunction prevention apparatus according to the present invention,

Figure 3 is a flow chart showing the principle of the operation of the improved rolling mill AGC work roller malfunction prevention apparatus according to the present invention.

Explanation of symbols on the main parts of the drawings

1 ... flapper 2 ... nozzle

3 ... coil 4 ... torque motor cover

5 ... Flexer Tube 6 ... Upper Magnet

7. Armature 8. Lower magnet

9 ... Feedback Spring 10 ... Drain Union

11 ... Spool left end euro 12 ... Spool right end euro

13 ... bushing (sleeve) 14 ... end cap

15 ... spool 16 ... inlet orifice

17 ... inlet filter tube 18 ... spool inlet hole euro

19 ... spool right hole flow path 20 ... valve body

21 ... Hydraulic pressure sensor 22 ... Control port C2 (C2)

23 ... Main pressure port (P) 24 ... Return port (R)

25 ... control port C1 (C1) 26 ... AGC cylinder

27. AGC MP scale or position sensor

28-1 ... roller lower work roller 28-2 ... roller upper work roller

28-3 ... hot rolled material

29 ... load cell 30 ... comparator

31 ... Deviation trigger circuit 32 ... Relay for input signal selection

33 ... Servovalve reference setpoint 34 ... Comparative derivative controller

35 ... Servo valve motion controller 36 ... Servo valve control circuit

40 ... Servo Valve

The newly improved rolling mill AGC work roller malfunction preventing device according to the present invention, unlike the conventional system using only the feedback value from the position sensor attached to the AGC cylinder in order to achieve the above object, the hydraulic pressure in the C2 port side hydraulic circuit An additional sensor is attached and the data signal from it enables fast and stable rolling mill AGC.

The AGC work roller malfunction prevention device of this rolling mill is mainly composed of AGC cylinder, servo valve, position sensor, servo valve control means, hydraulic pressure sensor and deviation comparison control circuit. That is, the AGC work roller malfunction preventing device according to the present invention is connected to the rolling mill AGC work roller having an upper roller and a lower roller AGC cylinder for adjusting the height of the lower roller; A servovalve regulating the vertical position of the AGC cylinder by supplying variable hydraulic pressure; A position sensor for measuring the vertical position of the AGC cylinder; A servovalve control means for controlling the operation of the servovalve by comparing the servovalve reference value set by the user with the positional data indicating the vertical position from the position sensor; In the conventional rolling mill AGC work roller malfunction prevention device comprising:

The servo valve further includes a hydraulic pressure sensor for sensing the pressure of the AGC cylinder control fluid, the servo valve control means, if a predetermined deviation occurs between the hydraulic value input from the hydraulic pressure sensor and the position data from the position sensor A deviation comparison control circuit for adjusting the servovalve by comparing the servovalve reference value and the hydraulic value is further included and improved, so that it has a structure and a combination which enables a stable operation by quickly detecting an instability factor and a phenomenon of the system.

Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings. Figure 1 shows a schematic diagram showing the configuration of the conventional rolling mill AGC work roller malfunction prevention device, while Figure 2 shows a schematic diagram of the basic operating principle of the improved rolling mill AGC work roller system according to the configuration of the present invention, AGC Since the basic configuration of the cylinder and servovalve is similar to the prior art, the repeated description thereof will be omitted.

In the present invention, it has a configuration constructed basically on the same basis as the conventional rolling mill AGC system described above, the servo valve 40 is further provided with a hydraulic pressure sensor for rapid automatic control, the control means 36 the hydraulic pressure detection A control circuit for comparing the hydraulic value, which is the feedback value from the sensor, and the position data, which is the feedback value from the position sensor 27, is further provided.

The hydraulic pressure sensor 21 detects a control instability that causes an equipment trouble while being extinguished and extinguished very briefly between the servo valve 40 and the AGC cylinder 26 which directly control the AGC cylinder 26. As an excitation sensor, it is provided in the hydraulic circuit of the C2 port 22 side which is a hydraulic inlet area between the AGC cylinder 26 and the servovalve 40. The hydraulic pressure detection value detected by the hydraulic pressure sensor 21 is inputted and compared to the circuit in the servovalve control means similarly to the position control error compensation value (MP scale variation value) of the AGC cylinder 26. This is to correct the error value quickly to compensate the input current signal to the servovalve.

In the lower part of FIG. 2, the hydraulic value-position data comparator 30, the deviation generation trigger circuit 31, and the input signal selection relay (in addition to the reference value set value 33, the comparison differential controller 34, the servovalve operation controller 35), Control means 36 having a structure / combination comprising 32 are shown. The hydraulic pressure-position data comparator 30 inputs the hydraulic pressure value from the hydraulic pressure sensor 21 and the position data from the position sensor 27 and compares the two input data and is proportional to the difference. The gain output is input to the deviation generation trigger circuit 31. In this rolling mill AGC work roller system, the deviation generation trigger circuit 31 does not output an output signal when the input signal does not exceed the deviation set by the user. By switching 32) to contact B, it is possible to have a structure that causes the hydraulic pressure to be the input feedback value of the lower differential control controller 34. That is, the feedback value (hydraulic value) detected by the hydraulic pressure sensor 21 and input to the control means 36 and the feedback value (position data) detected by the position detection sensor 27 and input to the control means 36 are It is inputted to the comparator 30 and compared, and it is determined whether the deviation generation trigger circuit 31 operates according to the deviation of the hydraulic value and position data compared by the comparator 30, and the emergency situation is a case where the deviation is momentarily increased. In this regard, the hydraulic value from the hydraulic pressure sensor 21 is used as a feedback value, not the position data from the position sensor 27.

For example, if the deviation signal between the hydraulic pressure value and the position data is ± 1 V, and less than that, the system is in a stable state, and the input signal selection relay 32 is not operated without causing the deviation occurrence trigger circuit 31 to operate. ) Is maintained at the contact point B, and thus the servovalve control means 36 compares this value with a reference value set by the user for the servovalve adjustment by using only the position data from the position sensor 27 as a feedback value. It is input to the differential controller 34 and drives the servovalve through the servovalve operation controller 35. On the contrary, that is, when the deviation signal between the hydraulic value and the position data is ± 1V or more, the system is in an unstable state and the deviation generating trigger circuit 31 operates the selection relay 32 to open the B contact point. And the contact point A is connected, so that the servovalve control means 36 uses the hydraulic pressure value from the hydraulic pressure sensor 21 as a feedback value and compares this value with a reference value set by a user for adjusting the servovalve. Input to the (34) and to drive the servo valve through the servo valve operation controller 35.

3 is a flow chart illustrating the operation of the rolling mill AGC work roller malfunction prevention device of the present invention for easy understanding of the whole process. First, when the system is operated (S100) and the user sets the servovalve reference value (S110), the initial position of the valve is detected by comparing the initial position data of the cylinder with the reference value (S120 to S140). Next, the pressure sensor 21 and the position sensor 27 detect the operation of the servovalve and the movement of the AGC cylinder as feedback values, respectively, and compare them in the comparator 30 so as not to exceed the deviation set by the user. If the data is used as a feedback and exceeds the hydraulic pressure, the servo valve is operated (S150 to S200).

The malfunction prevention device of the rolling mill AGC working roller according to the present invention is not limited to the expression disclosed in this detailed description, and all the additions, modifications, and modifications of the invention are provided without departing from the scope of the technical idea of the invention described in the utility model registration claims. Of course, it can be applied to. For example, in this detailed description, the upper work roller and the lower work roller are distinguished from each other and the AGC cylinder is described on the basis of being connected to the lower work roller. However, this is only for convenience of explanation and understanding. Can be.

The malfunction prevention device of the rolling mill AGC work roller according to the present invention can detect and compensate an error signal more quickly than when the AGC cylinder position control value is a feedback value according to the prior art. It can solve instability and maximize efficiency. Quickly detects and controls abnormal phenomena occurring between servovalve and AGC cylinders to detect equipment troubles caused by the system's control instability early and stabilize it before entering into instability. The efficiency can be improved.

Claims (3)

An AGC cylinder connected to a rolling mill AGC working roller having an upper roller and a lower roller to adjust a height of the lower roller; A servo valve for supplying variable hydraulic pressure to the AGC cylinder to adjust its vertical position; A position sensor for measuring a vertical position of the AGC cylinder; A servovalve control means for controlling the operation of the servovalve by comparing a servovalve reference value set by a user with position data representing a vertical position from the position sensing sensor; In the rolling mill AGC work roller malfunction prevention device comprising: The servo valve further includes a hydraulic pressure sensor for sensing the pressure of the AGC cylinder adjustment fluid, The servo valve control means controls the servovalve by comparing the servovalve reference value with the hydraulic pressure value when a predetermined deviation occurs between the hydraulic pressure value input from the hydraulic pressure sensor and the position data from the position sensor. Rolling mill AGC work roller malfunction prevention device further comprises a deviation comparison control circuit. The method of claim 1, And the hydraulic pressure sensor is installed in a C2 port side hydraulic circuit which is a hydraulic inlet area between the AGC cylinder and the servovalve. The method of claim 1, The deviation comparison control circuit includes a comparator for receiving the servovalve reference value and the hydraulic pressure value; A deviation generation trigger circuit configured to receive an output value of the comparator and output a trigger signal when a deviation set by a user is exceeded; An input signal selection relay for selecting one of the hydraulic pressure value and position data as a feedback value by the deviation generation trigger circuit; Rolling mill AGC work roller malfunction prevention device comprising a.