JPS59120309A - Tension control device of mandrel bar - Google Patents

Abstract

PURPOSE:To obtain a product having high accuracy without fluctuating the tension acting on a mandrel bar by fixing one end of the mandrel bar to a traveling device and controlling the torque of a driving motor of the traveling device to a prescribed tension. CONSTITUTION:A mandrel bar 3 is fixed to a fixing device 12 of a mandrel bar traveling device 11 and a shell 2 is inserted onto the bar 3. The device 11 is advanced at a set speed to bite the shell 2 in a mandrel mill so that the shell is rolled. The torque in a decelerating direction is generated in a driving motor 13 and tension is generated in the bar 3. The tension acting on the bar 3 is proportional to the driving torque of the motor 13. The driving torque is controlled by a torque control device 18 from the motor terminal voltage, armature current and angular speed fed back thereto until said torque coincides with the torque standard calculated by an arithmetic device 17 in accordance with the tension standard set to meet the rolling schedule.

Description

[Detailed description of the invention] [Technical portion of the invention! The present invention relates to a device for controlling the tension of a mandrel bar of a mandrel mill that performs rolling by restraining the movement of a mandrel bar inserted into a tube.

[Technical background of the invention]

Generally, in order to manufacture seamless steel pipes, a mandrel bar is inserted into the pipe material C (hereinafter referred to as shell) that has been perforated with a viar, etc., and a rolling mill equipped with grooved rolls is placed adjacent to it. The material is placed between the rolls of a mandrel mill and continuously rolled to achieve a predetermined thickness, length, and roundness. Rolling with a mandrel mill using a mandrel bar is different from other floor net rolling of wire rods and rods, and the behavior and operability of the mandrel bar during rolling determine the productivity of the mandrel mill and the quality of the product. Let me tell you a big parable.

1'tt, te, mandrel mill has mandre/l/
There is a full-float type mandrel mill in which a mandrel bar is inserted into the shell at the input rotary root of the mill, and rolling is completed without operating the mandrel bar during rolling. In the WL mandrel mill, the mandrel bar fluctuates within the shell during rolling, making it impossible to improve accuracy in wall thickness, length, roundness, etc.

For this reason, before inserting the mandrel bar into the shell on the mandrel mill table and cutting the shell into the mandrel mill, one end of the mandrel bar is fixed to the mandrel bar traveling device to control the movement of the mandrel bar. There is an MPM type mandrel mill in which the mandrel bar is bitten into the mandrel mill until it is restrained and rolling is performed, and the advancing speed of the mandrel bar is controlled by moving the mandrel bar traveling device during rolling.

In cases where rolling is performed only with the first rolling mill or the final rolling mill of this mandrel mill, this model is used as shown in Fig. 1, where the mandrel bar 3 is rolled between the grooved rolls and the rolling mill. The rear tension TBi acts on the mandrel bar 3, the front tension TBI+/ of the mandrel bar 3 is zero, and the rear tension Tmi and the front tension Tmi+/ of the shell are both zero. Pl, o, rolling torque G
io, G10 is determined by the following equation.

Gio=TBi-R1+, 2al-P:1. o--
---・-(/1 Here, 101 is the shape and dimensions of the groove rolling roll, the shape and dimensions of the shell before and after rolling, and the mandrel bar.
Depends on the diameter? fl is the average roll radius of Δ1', and aj is generally the core ai-Ui in rolling such as plate or long steel rolling.
Dynamic expression expressed as O/I-' 10! *This corresponds to +.

In addition, since there is always a relative velocity between the mandrel bar 17 and the shell, the coefficient of kinetic friction lzi between the mandrel bar 3 and the shell is expressed by TBi and P
There is a relationship between υ and io.

TBj-2μm・plo...(2) The above is for single-fr rolling, but the mandrel mill is shown in Figure 1 for "'1"'All<, counting rolling. It is a continuous type rolling mill in which the mills are connected (3 stands) adjacent to each other, and in continuous rolling, Qji force or compression force acts on the H rolling mills (rolling rolls) on the upstream and downstream sides. .

In 1ν1, the axes of the rolling rolls are arranged parallel to each other for convenience, but in reality, the axes are at an angle of dθ.

are arranged with an intersection angle of .

Then, focusing on the intermediate stand 1, the rolling torque Gj of the stand 1 can be expressed by the following equation.

Gi=TBi-R1-TBi+/lFi+7+, 2ai
Pi+ΔGib-AG5. f・・・・・・・・・(
3) Here, ΔG1 [) is the torque change due to the rear tension Tmi generated in the shell λ as seen from the stand 1, and ΔGif is the torque change due to the generation of the forward tension Tmi, 4-7, in the shell λ as seen from the stand 1. This is the amount of torque change due to this.

[Problems with background technology]

As is clear from the above equations (1) to (3), if the tensions TBi and TBi+/ acting on the mandrel bar change, the rolling torque G1, the rolling load vPi, and even the tension or compression force acting on the shell no. This fluctuates, interfering with stable rolling and reducing accuracy in wall thickness, length, roundness, etc., leading to a decline in yield and product quality.

[Purpose of the invention]

The present invention has been made to improve the above-mentioned conventional problems.

Its purpose is to create a mandrel bar that can stabilize the rolling process and obtain products with high precision quality by controlling the tension acting on the mandrel bar to a predetermined value. The purpose is to provide a tension control device.

[Summary of the invention]

In order to achieve the above object, the present invention has a rolling mill using full rolls and a mandrel bar, and rolls the mandrel bar between the full moon rolls with the mandrel bar inserted into the pipe. At one end, the mandrel bar is fixed in a mandrel mill fixed to a cold running device.
By controlling the drive torque generated in the drive unit of the traveling device to a certain set value, the mandrel bar
The general idea is to control the tension so that it becomes a predetermined tension.

[Embodiments of the invention]

An example of the implementation of the present invention will be described below with reference to FIGS. 3 and 1.

In Fig. 3, the mandrel bar 3 inserted into the shelco is arranged in 8 rows between grooved rolls for rolling.
Its rear end is fixed to a fixing device (al, 2) on the running gear ll.

The traveling device // is driven by the drive motor 13, and the drive) j' l,′
It is detected by a small flow detector/S and a speed detector L. In the figure, / is the torque reference simulation device 1a, and the calculation device ffi/7 is set according to the squirrel. .

This l·lux reference is then input to the torque control device/g.

This torque control device (47g is controlled to match the driving torque of the motor based on the motor terminal voltage, armature current, and angular velocity star detected by each of the above-mentioned detectors /'l, 1!, and 6, based on the +7 torque reference. do.

Next, the operation will be explained. First, the mandrel bar 3 is fixed to the fixing devices t/, l of the mandrel bar traveling device //, and the shell is inserted into this mandrel bar 3. Incidentally, the mandrel bar 3 may be fixed after the shell 2 is inserted. Thereafter, the traveling device/l is moved forward at a set speed to engage the shell 2 in the mandrel mill and start rolling. At this time, the set speed m- of the traveling device // may be any speed until just before the shell 2 bites into the mandrel mill, but
After biting, the shell 2 and mandrel bar 3 are set to a lower speed than the rolling speed. Since / is set to a value lower than the rolling speed, the drive motors / and ? have the same torque in the deceleration direction.
T-drel bar 3 between mandrel mill and traveling device l/
A netting state occurs through 7, and tension is generated in the mandrel bar 3.

At this time, the relationship between the tension acting on the mandrel bar 3 and the drive torque of the drive motor 13 of the traveling device l/ is expressed by the following equation.

()B - ωB,..., TB・VB+α×1=(4') where ()B is the drive torque, (IIB is the angular velocity of the drive motor/3, TB is the tension acting on the mandrel bar 3, V
B is the speed of the mandrel bar 3, and αi3 is a value determined by the specifications of the traveling device //. And mandrel bar-3
The speed J&vH of is the mandrel bar, and if 7 is a rigid body that does not deform plastically, the angular velocity tWωB of the drive motor/3 and the traveling device/
The trunk torque ()F, which is a value determined by the reduction ratio of /, is given by the following equation.

QBwβB' E ・I a,, /(41B ,,,
,,, (5) Here, E is the back electromotive force, ■δ is the armature 1
F flow and βB are constants that depend on the specifications of the traveling device l/.

Although it is still the difference between back electromotive force E, motor terminal voltage, and armature voltage sieve IaFta, the following relationship can be derived.

QB-(ET-IaRa)IaβB/ωB --
・-(A) Here, RaILj force is resistive, and ET is the motor terminal voltage.

From the above, it can be seen that the <942 force TH acting on the mandrel bar 3 is proportional to the drive torque (]B of the drive motor 13. Therefore, when the drive torque GB is set to 1'?, the thickness, length, roundness, etc. In order to keep constant, the motor terminal voltage, armature current, which is fed back by the torque control device 7g,
The driving torque obtained by equation (6) may be the angular velocity.
The torque may be controlled so as to match the torque reference calculated by 7.

In addition, Fig. V shows another embodiment, which differs from the previous embodiment in that a tension detecting device/9 such as a load roller is installed in the fixing device/2 of the traveling device//2. It's in Toru.

By doing this, in the embodiment described above, the drive torque was determined from the set tension and the tension was controlled, but in this embodiment, the drive is performed so that the tension signal of the tension detection device y/qp etc. is constant. Try to control the torque.

Figure 5 shows a further embodiment in which the driving torque is directly set without tension setting or tension testing. Even in this manner, the accuracy of wall thickness, length, roundness, etc. can be improved.

Furthermore, in the embodiment shown in FIG. 3, a method was described in which the tension is controlled by setting the traveling speed/l lower than the rolling speed, generating deceleration torque, and controlling this torque.
1 or higher may be used so that an acceleration torque is applied to push the bar at a speed higher than the rolling speed, and this acceleration torque is controlled.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, one end of the mandrel bar of the mandrel mill is fixed to the running device, and the driving torque generated in the drive type 1 of this running device is transferred to the mandrel bar. Since the tension acting on the mandrel bar was controlled to be a predetermined tension, the tension acting on the mandrel bar did not fluctuate, and therefore the rolling torque, rolling load, and tension or compression force acting on the shell remained constant. It has many effects such as being able to obtain products with high precision in terms of length, negative circularity, etc.''1-
Ru.

[Brief Description of the Drawings] Fig. 1 is a schematic diagram of the rolling state by a rolling mill, Fig. 2 is a schematic diagram of a mandrel mill, Fig. 3 is a system diagram of the mandrel bar tension control device according to the present invention, Fig. 1 and FIG. 5 are similar system diagrams to FIG. 3 showing another embodiment. /...grooved kiloroll, co...pipe material 1. ?・Mandrel bar 1/c・Traveling device, /2...fixing device, 13...driving motor, 7g/controlling device 1, /q...tension detection device. Applicant's representative Inomata Seedling tube Figure 1 Figure 2 Pi-I Pi
Day+1 Figure 3 1; Figure 4 Figure 5 471

Claims (1)

[Scope of Claims] / A traveling device equipped with a fixing device for fixing one end of a mandrel bar inserted into a tube to be rolled, a drive motor for driving this traveling device, and the mandrel bar. A mandrel bar tension control device comprising: a control device for controlling the drive torque of the drive motor so that the tension acting on the mandrel bar becomes a predetermined tension. The mandrel bar tension control device according to claim 10, wherein the traveling device is equipped with a tension detection device for directly detecting the tension acting on the mandrel bar.