JPH0523849B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for measuring eccentric load on a back-up roll and a method for controlling roll eccentricity in order to prevent plate thickness fluctuations due to roll eccentricity of a rolling mill. [Prior Art] Conventionally, for example, in a hot finishing rolling mill, when the bearing key part of a back-up roll is brought into contact with the pressure-receiving surface, the sleeve fitted into the key part at the end of the roll is deformed due to this rolling load. occurs, or
Alternatively, roll eccentricity occurs due to collapse of the gap between the key and the sleeve, which reduces the rolling load at this location, causing a problem in that the thickness of the plate to be rolled varies. When this roll eccentricity occurs, the rolling load decreases, so that, for example, an automatic plate thickness control device provided on the back-up roll acts in a direction to widen the roll gap. This means that due to the collapse of the gap between the key and the sleeve or the deformation of the sleeve, even though the roll gap is more open than the predetermined gap, the roll gap will be moved further in the opening direction, causing an even larger variation in plate thickness. become. In order to deal with the above-mentioned problems, conventional methods have been used to detect or estimate the eccentricity of the upper and lower back-up rolls of a rolling mill and control the rolling device. Showa 59-
A technique shown in Publication No. 150612 is disclosed. This technology uses a rolling load detector on the rolling mill and rotation angle detectors for the upper and lower back rolls to detect rotation angles at fixed rotation angles or fixed time intervals, and rolling weight values corresponding to the angles. To memorize and calculate the difference between the memorized value of the rolling load at a certain rotation angle and the memorized value of the rolling load from the angle when the upper and lower back up rolls are rotated by an integral multiple of one rotation from the certain rotation angle. This is a roll eccentricity detection method in which the eccentricity of the upper and lower back-up rolls is detected separately. To explain this specifically, for example, the reference position 53 of the upper back-up roll 51 shown in FIG. 6 is always rotated by θ° from the vertical direction of the rolling mill;
By memorizing the angle α° of the reference position 54 of the lower back-up roll 52 from the vertical direction and the rolling load at that time, the lower back-up roll 5
When the reference position 54 of No. 2 changes, that is, the value of α changes, the rolling load change corresponding to the change in position, that is, the rolling load change caused by the rotation of the lower roll 52, is the roll of the lower roll 52. Assume eccentric load. Similarly, regarding the upper back up roll 51, the rotation angle and rolling load change of the upper back up roll 51 are detected when the lower back up roll 52 is at a certain rotation angle, and the upper back up roll 51
The eccentric load is assumed to be . [Problems to be Solved by the Invention] The conventional method described above has the following problems. (b) In order to detect the roll eccentric load at a certain fixed position of the upper and lower back up rolls, if the fixed position is changed, a difference will occur in the roll eccentric load. (b) Conventionally used rotation angle detectors generally use pulse generators, etc., and these are used to detect relative angles, and the timing is important during measurement and actual rolling. There was a problem that it was difficult to match. (c) Roll eccentric load does not necessarily vary proportionally with the load during rolling, but these are not taken into account and must be measured and corrected each time. The present invention has been made to solve the above-mentioned problems, and provides a method for measuring and controlling a roll eccentric load that can accurately detect the roll eccentric load, accurately detect an angle, and cope with load fluctuations. [Means for Solving the Problems] A first aspect of the present invention is to divide the roll center of the upper and lower back rolls of a rolling mill at a predetermined angle, and install an absolute rotation angle detector on each roll to recognize the divided position. The rolling mill is rotated at an appropriate speed and a rolling load is applied to the roll, and while the rolling load is changed, the load at the dividing point of the upper and lower back rolls and each combination of the changed rolling load is measured. This is a rolling mill roll eccentric load measuring method characterized in that the average value of the load fluctuations at the same division point of the upper and lower back up rolls is memorized and determined from the above combination as the roll eccentric load of each back up roll. In addition, the second invention divides the roll center of the upper and lower back rolls of the rolling mill at a predetermined angle,
An absolute rotation angle detector that recognizes the divided position is installed on each roll, the rolling mill is rotated at an appropriate speed and a rolling load is applied to the roll, and the upper and lower back up rolls are divided while changing the rolling load. Measure and memorize the load at each combination of point and changed rolling load, and from the above combinations, the average value of the load variation at the same dividing point of the upper and lower back up rolls is taken as the roll eccentric load of the back up roll, and the load is calculated during rolling. The rolling load is corrected by adding or subtracting the roll eccentric load to the rolling load at a position corresponding to the absolute rotation angle of the back-up roll during rolling. This is a roll eccentricity control method for a rolling mill characterized by changing the roll gap in proportion to a measured load variation. [Function] As described above, in the present invention, the absolute rotation angle of the back up roll is recognized, and the back up in all combinations of these angles of the upper and lower rolls, as well as in combinations when the rolling load of the rolling mill is variously changed, is recognized. By measuring and storing the load applied to the back up roll, the roll eccentric load is determined, and by controlling and adding this load to the actual rolling load to correct the rolling load, the influence of the eccentric load on the back up roll can be reduced. This ensures uniform rolling at all times even when the rolling load is changed. [Example] An example of a control device for carrying out the present invention will be described in the first example.
As shown in the figure. In the figure, 1a and 1b are the upper and lower work rolls of the rolling machine, 2a and 2b are the upper and lower back-up rolls, and each roll 2a and 2b has a coupling 3a and 3b at its shaft end to ensure the absolute rotation of the roll. Absolute rotation angle detectors 4a and 4b for recognizing angles are coupled. 5 is a roll eccentricity calculation device;
A load signal from a load cell 9 that detects the load of the back-up roll, an absolute rotation angle detector 4a,
4b is input, and the roll eccentric loads of the upper and lower back up rolls 2a and 2b are calculated by making the roll rotation angle correspond to the load. At the same time, this calculated value is transferred to the next roll eccentricity control output calculation device 6.
is input. In the control output calculation device 6, the simultaneously inputted calculation values are inputted as a control signal to the next hydraulic pressure reduction control device 7 in accordance with the timing of the angle signal. Reference numeral 8 denotes a back-up roll rolling down device, which adjusts the rolling load to correct roll eccentricity based on the control signal. Next, a method for measuring the load on roll eccentricity will be explained. In this example, a case where the rotation angle of the upper and lower back-up rolls is divided into n divisions as shown in FIG. 2 will be explained. First, the rolling mill is set to a predetermined rotational speed to create a kiss roll state, and the rolling reduction is lowered to around the lowest rolling load of normally performed rolling. In this state, each dividing point of the rotation angle of the back up roll is the load point of the roll, that is, when the upper back up roll is at the position directly above, and the lower back up roll is at the position directly below, the dividing point of the upper and lower rolls is Measure the loads in all combinations. Table 1 is a table showing the combinations of the dividing points.
The index in the first row on the left...i... is the n dividing point of the upper back up roll, and the index in the first column on the upper side...j... is n in the lower back up roll.
...a _ij ... is the detection weight at the combination point of each division.

【table】

Claims (1)

[Scope of Claims] 1. The center of the rolls of the upper and lower back-up rolls of the rolling mill is divided at a predetermined angle, and an absolute rotation angle detector that recognizes the divided position is installed on each roll,
The rolling mill is rotated at an appropriate speed and a rolling load is applied to the rolls, and while changing the rolling load, the division points of the upper and lower back-up rolls and the loads at each combination of the changed rolling loads are measured and memorized, and the above-mentioned A method for measuring roll eccentric load of a rolling mill, characterized in that the average value of load fluctuations at the same dividing point of the upper and lower back-up rolls is determined as the roll eccentric load of each back-up roll. 2. The roll center of the upper and lower back-up rolls of the rolling mill is divided at a predetermined angle, and an absolute rotation angle detector that recognizes the divided position is installed on each roll,
The rolling mill is rotated at an appropriate speed and a rolling load is applied to the rolls, and while changing the rolling load, the division points of the upper and lower back-up rolls and the loads at each combination of the changed rolling loads are measured and memorized, and the above-mentioned From the combination of , the average value of the load fluctuation at the same dividing point of the upper and lower back-up rolls is taken as the roll eccentric load of each back-up roll, and the rolling load at the position corresponding to the absolute rotation angle of the back-up roll during rolling is applied to the roll. A roll eccentricity control method for a rolling mill, characterized by correcting a rolling load by adding or subtracting an eccentric load. 3. The roll eccentricity control method for a rolling mill according to claim 2, characterized in that the roll gap at a position corresponding to the absolute rotation angle of the back-up roll during rolling is changed in proportion to the measured load variation.