Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
  • B21B37/58—Roll-force control; Roll-gap control
  • B21B37/62—Roll-force control; Roll-gap control by control of a hydraulic adjusting device
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B2203/00—Auxiliary arrangements, devices or methods in combination with rolling mills or rolling methods
  • B21B2203/18—Rolls or rollers
  • B21B2203/187—Tilting rolls
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B31/00—Rolling stand structures; Mounting, adjusting, or interchanging rolls, roll mountings, or stand frames
  • B21B31/02—Rolling stand frames or housings; Roll mountings ; Roll chocks
  • B21B31/04—Rolling stand frames or housings; Roll mountings ; Roll chocks with tie rods in frameless stands, e.g. prestressed tie rods
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21B—ROLLING OF METAL
  • B21B31/00—Rolling stand structures; Mounting, adjusting, or interchanging rolls, roll mountings, or stand frames
  • B21B31/16—Adjusting or positioning rolls
  • B21B31/20—Adjusting or positioning rolls by moving rolls perpendicularly to roll axis
  • B21B31/32—Adjusting or positioning rolls by moving rolls perpendicularly to roll axis by liquid pressure, e.g. hydromechanical adjusting

Definitions

• the invention relates to a control device for positioning the upper part of a four-column rolling stand, which has four actuating cylinders which can be pressurized and which are each arranged in pairs opposite one another on the side of the rolling belt and each provided with a position sensor for measuring their stroke position, the control device depending on the measured values of the position sensors Outputs control signal for lifting, lowering or pivoting the upper part of the scaffold taking into account a length difference value determined from the difference in the lifting position.
• length sensors are used to check the synchronism and the alignment of the cylinder pistons.
• the measurement signals supplied by these position sensors are generally subject to errors, so that the actual stroke position of the positioning cylinders can deviate from the measured one. Because of this deviation caused by measurement errors, there is also a danger of the upper part of the scaffolding becoming distorted if all the length values determined by the position sensors are identical.
• Torsion of the upper part of the scaffold can also be avoided by operating one of the four adjusting cylinders under pressure control.
• the measured actual pressure value of the adjacent cylinder can serve as the pressure setpoint for this cylinder.
• the disadvantage of this The procedure is that the target value for the pressure-controlled adjusting cylinder is only established after the remaining three adjusting cylinders have been adjusted. This means that such control has only a reduced control dynamics.
• the object of the invention is to provide a control device of the type mentioned with good control dynamics, which emits a control signal corrected by the measurement errors of the length measurement for raising, lowering or pivoting the upper part of the scaffold.
• the jack cylinders of at least one pair of jack cylinders each have a sensor connected to the control device for detecting the reaction force absorbed by the jack cylinders and
• control device for at least one of these adjusting cylinders outputs a control signal determined taking into account a force difference value, the force difference value being equal to the difference of the reaction forces of the adjusting cylinders of the adjusting cylinder pair multiplied by an amplification factor.
• the invention is based on the finding that different forces of different forces are absorbed by the pitch cylinders when the upper frame part of the roller is twisted. An unequal stroke position leads to an unequal loading of the actuating cylinders.
• the measurement errors of the length measurement are detected by the result of an additional force measurement, by which, for example, the Pressure values measurable reaction forces in the pitch cylinders can be determined. If the reaction forces of the cylinders of a pair of adjusting cylinders differ from one another, the control device determines a correction value from this difference, by means of which the error in the length measurement is corrected. For this purpose, the force difference is multiplied by a proportionality factor, by means of which the result of the force measurement is transferred to a length value for the stroke adjustment. In this way it is possible to compensate for the errors in the length measurement in the shortest possible time and to create a control unit with good control dynamics and stable control.
• the invention makes it possible, by means of a force-dependent correction of measurement errors in the length measurement, that all actuating cylinders of a four-column rolling mill are equally loaded and consequently the upper frame part of the rolling mill is kept stress-free.
• the control behavior of the control device can additionally be improved in that the control device has number memories in which the force difference values determined for an actuating process can be stored in such a way that they can be called up for determining the correction values of the subsequent actuating process. These number memories make it possible to use a control loop by which the force difference values can be determined iteratively starting with an initial value. Such a controller has an integrating behavior, by means of which an undesired abrupt adjustment of the setpoints is avoided. In addition, it makes sense if the control device has number memories in which the force difference values determined for each actuating process can be added up, and that the control device emits a warning signal when a limit value of this sum is exceeded. In this way, an improper misalignment of the upper part of the scaffold is reliably avoided.
• the function of the position encoder can be monitored in that the control device when a Limit value for the differential amount of the reaction forces absorbed by the pitch cylinders of a pair of pitch cylinders emits a warning signal.
• a suitable control device is characterized in that the control device emits a warning signal when a limit value for a sum formed from the addition of the difference in reaction forces determined for each pair of actuating cylinders is exceeded.
• 1 is a plan view of a four-column rolling stand
• FIG. 2 shows a schematic illustration of a control circuit for positioning the upper housing part of the rolling stand according to FIG. 1.
• the four-column rolling stand has a stand upper part 5 carried by four adjusting cylinders 1, 2, 3, 4.
• the positioning cylinders 1, 2, 3, 4, as positioning cylinder pairs A, B, are located laterally opposite one another the rolling mill 6 is arranged.
• the pistons of the adjusting cylinders 1, 2, 3, 4 can be raised and lowered by pressurizing the adjusting cylinder space with hydraulic fluid.
• Each of the positioning cylinders 1, 2, 3, 4 has position sensors 7, which detect the stroke position LA1, LA2, LB3, LB4 of the pistons of the positioning cylinders 1, 2, 3, 4, and force sensors 8, each of which prevails in the cylinder space Supply pressure of the hydraulic fluid proportional signal FA1, FA2, FB3, FB4 as a measure of the reaction force absorbed by the jack cylinders.
• the position transducers 7 and force transducers 8 are connected to a control device 10 via signal lines 9.
• Control valves (not shown) are connected to four outputs of the control device 10 via control lines 11, by adjusting the hydraulic pressure in the adjusting cylinders 1, 2, 3, 4 as a function of the control signals SA1, SA2, SB3, SB4 emitted by the control device 10 for lifting, Lowering or pivoting the upper part of the scaffold 5 is changeable.
• the control device 10 has a control circuit 12, which is shown in FIG. 2.
• the value T of the absolute inclined position of the upper part 5 of the stand, related to the longitudinal axis I of the roll stand, is included in the control circuit 10.
• the inclined position makes it possible to roll rolled strips with a wedge-shaped cross section in the case of a wedge-shaped roll gap.
• T (LA1 + LA2-LB3-LB4) / 2 + dT, where dT is the value by which the pistons of the adjusting cylinders 1, 2, 3, 4 are relative to the previous swivel position to be raised or lowered.
• Setting step can be set to zero.
• the above-described iterative determination of the length difference values CA, CB has the advantage that the position of the setting cylinders 1, 2, 3, 4 is not abruptly corrected in one step, but the position of the setting cylinders is adjusted to the best possible position in several successive steps .
• the control loop thus has an integrating behavior with high stability. If it is found in practical operation that this stability or the accuracy of the control loop is not sufficient, the length difference values CA, CB can be determined as an alternative to the above-mentioned equations using the following equations:
• CA: CA -f * (FAl-FA2) / 2
• CA: CA + f * (FBl-FB2) / 2
• CA: CA -f * (FAl-FA2-FB3 + FB4) / 4
• the control device issues a warning signal to the machine operator as a sign that the function of the position transducer must be checked.
• the control device emits a warning signal as a sign of the danger of an inadmissible inclination of the upper part 5 of the roll stand related to the transverse axis II if the sums of the correction values CA, CB also stored in a number memory of all adjusting operations exceed a maximum value.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Control Of Metal Rolling (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=6445487

Family Applications (1)

Country Status (4)

Families Citing this family (1)

Citations (3)

• 1991
  • 1991-11-25 DE DE19914138639 patent/DE4138639C1/de not_active Expired - Fee Related
• 1992
  • 1992-11-19 JP JP5509765A patent/JPH08500293A/ja active Pending
  • 1992-11-19 WO PCT/EP1992/002659 patent/WO1993010921A1/de active IP Right Grant
  • 1992-11-19 EP EP92924597A patent/EP0614404B1/de not_active Expired - Lifetime

Patent Citations (3)

Non-Patent Citations (3)

Also Published As

Similar Documents

Legal Events