JP2001205308A - Device for calculating retained force and abnormal rolling detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an arithmetic unit for retained force for calculating the retained force value of rolling, each time the materials are passed through each roll stand, of a motor for feeding the rolling materials to a mandrel mill. SOLUTION: This arithmetic unit 11 for the retained force is provided with a 1st arithmetic part 11A and 2nd arithmetic part 11B for calculating the retained force value F1 from the calculated value of the torque of a bar retainer driving motor 2A and the acceleration/deceleration torque Ta of a driving machine system, just before biting detecting part 11C for detecting the material just before the rolling material is bitten with the mandrel mill S, a lock-on arithmetic part 11D with which a retained force value F1 is stored and also a retained force F0 just before biting is calculated by removing the torque TL component of the mechanical loss from the stored retained force value F1 when a signal just before the rolling material is bitten into the the mandrel mill S is outputted from the just before biting detecting part 11C, and a rolling retained force arithmetic part 11E for calculating the rolling retained force value F from the retained force value F1 and the retained force value F0 just before biting.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a retention force calculation for a motor for feeding a rolled material to a plurality of roll stands of a mandrel mill for rolling a seamless pipe, which calculates a rolling retention force value for each passing through each roll stand. TECHNICAL FIELD The present invention relates to a device and a rolling abnormality detection device capable of detecting the occurrence of a rolling abnormality at an early stage by the retention force calculating device.

[0002]

2. Description of the Related Art For example, in a mandrel mill used for manufacturing a seamless tube, there is a problem in that a lubricant is insufficiently applied to a mandrel bar, a rolling roll is not properly set, and a rotating speed of a rolling roll is not properly set. For example, a rolled material is compressed between roll stands of a mandrel mill to form a wrinkle, and conversely, a rolled material is subjected to excessive tension due to excessive tension and tearing of thin-walled rolling occurs. When a rolling abnormality occurs, a situation may occur in which rolling is stopped and treatment is performed for a long time.

Conventionally, a rolling abnormality is detected by detecting an overcurrent of a motor for driving a rolling roll or a motor for driving a mandrel bar. A method of detecting a torque current value) and judging a case in which the mandrel mill does not continuously exist within a predetermined allowable range of the rolling abnormality for a predetermined time for a predetermined time or more (for example, Japanese Utility Model Application Laid-Open No. 3-9203).
No.) is known.

That is, in Japanese Utility Model Laid-Open No. 3-9203, as shown in FIG. 4, for example, the allowable value β determined for the torque current value is a value that can be determined to be sufficiently abnormal due to occurrence of a rolling abnormality, that is, + (positive side) ), The motor is in a power running state, and the torque applied to the motor is determined to be excessive.

[0005]

However, in the above-described conventional method, the detected torque current value includes an element that varies independently of rolling, such as a mechanical loss torque and an acceleration / deceleration torque of the mandrel bar drive system. Therefore, in detecting a rolling abnormality, the torque current value is affected by the above-mentioned factors that vary independently of the rolling, and as shown in FIG.
Even if the set value β shown in (1) is provided, it is not accurate whether or not an element relating to the rolling itself fluctuates, and there is a problem that it is insufficient to reliably and early detect a rolling abnormality.

Further, according to the conventional method, a rolling abnormality is detected, and after a set time T2 hours after exceeding the allowable value β, a rolling abnormality is detected and the equipment is stopped. Since it took a long time to detect a rolling abnormality, a wrinkled and torn rolled material sometimes remained in the mandrel mill. When such a situation occurs, there is a problem that the rolled material must be gas-cut and removed, resulting in a loss caused by stopping the equipment for a long time.

The present invention has been made in order to solve the above-mentioned problem, and can calculate the torque of a motor involved in rolling itself as a rolling retention force value to obtain a detailed and proper behavior of the motor. Retention force calculator,
It is another object of the present invention to provide a rolling abnormality detecting device capable of monitoring a rolling retention force value calculated by the retention force calculating device and accurately detecting a rolling abnormality.

[0008]

In order to achieve the above-mentioned object, a retention force calculating device of the present invention always calculates a retention force value of a motor by a calculation unit, and immediately before the rolling material is caught in each roll stand. The retention force value at the time when the signal is input is stored, the torque corresponding to the mechanical loss is removed from the stored retention force value, and the retention force value immediately before the engagement is calculated. The rolling retention force value is calculated from the retention force value immediately before the rolling.

In this way, the rolling retention force value obtained by the calculation eliminates the torque and acceleration / deceleration torque corresponding to the mechanical loss that fluctuates independently of rolling, so that the rolling retention force value is reduced when rolling through each roll stand. It can be a true torque element of the motor to be provided, and the rolling behavior can be grasped in detail and properly.

Further, the rolling abnormality detecting device of the present invention has a retention force calculating device, and detects a rolling abnormality by comparing a rolling retention force value calculated by the retaining force calculating device with a preset allowable value. Each time a roll stand rolls, it is possible to detect rolling abnormalities reliably and at an early stage, not only to minimize equipment damage, but also to stop equipment such as stoppage due to the occurrence of torn materials. Loss of time can be minimized and minimized.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION
A retention force calculation device that calculates a torque of a motor that feeds a rolled material to a plurality of roll stands of a mandrel mill as a retention force value each time the roll material passes through each roll stand of the mandrel mill, and is calculated from a driving torque of the motor. A calculation unit that calculates a retention force value from the torque calculation value and the acceleration / deceleration torque of the drive mechanical system; a detection unit that detects immediately before the rolled material is bitten into the first roll stand of the mandrel mill; When a signal immediately before biting is output from the immediately before biting detection unit, the retention force value calculated by the calculation unit is stored, and a torque component corresponding to a mechanical loss is removed from the stored retention force value to bite. A lock-on calculation unit that calculates a retention force value immediately before engagement, and a retention force value output from the calculation unit and immediately before biting output from the lock-on calculation unit It is obtained by a rolling Ritendo force calculator for calculating a rolling Ritendo force value and a Tendo force value.

The retention force value calculated by the calculation unit is obtained by removing the acceleration / deceleration torque component from the torque calculation value of the motor applied each time the rolled material passes through each roll stand, and providing the torque and mechanical loss for rolling. After obtaining the load torque in the state having the above torque, the load torque is determined in consideration of the mechanical characteristics. The retention force value is continuously calculated as needed, and is output to the rolling retention force calculation unit and the lock-on calculation unit.

In the lock-on operation section, a signal immediately before the rolled material is bitten into the first roll stand of the mandrel mill is input from the biting detection section. Then, when the signal immediately before the engagement is input, the lock-on calculation unit
The above retention force value is stored. The lock-on calculation unit calculates a retention force value immediately before biting by removing a torque for rolling from the retention force value, and outputs the value to the rolling retention force calculation unit.

The rolling retention force calculation unit calculates the rolling retention force value from the retention force value continuously output as needed and the retention force value immediately before biting. That is, in the rolling retention force calculation unit, since the retained force value continuously output at any time includes the torque for the mechanical loss, the torque for rolling is removed from the retained force value, that is, the mechanical loss component is calculated. By removing the retention force value immediately before biting, which is the torque, from the retention force value, the true torque of the motor acting only on rolling can be obtained as the rolling retention force value.

Therefore, the rolling retention force value is a value obtained by removing the constant retention force value immediately before biting from the retention force value continuously and variably calculated as needed. Instead, a detailed and appropriate rolling situation can be obtained.

Further, a rolling abnormality detecting device of the present invention compares the above-mentioned retention force calculating device with a rolling retention force value calculated by the retention force calculating device and a preset allowable range of the rolling retention force value. It is provided with a comparison unit and a determination unit that determines the quality of the rolling state based on the comparison result by the comparison unit.

In the above configuration, the rolling abnormality detecting device includes:
The comparison unit compares the rolling retention force value calculated by the retention force calculation device with the set allowable range, and when the rolling retention force value exceeds the allowable range, the determination unit determines that the rolling is abnormal and stops rolling. You do it. In this way, it is possible to grasp in detail the motor behavior each time the rolled material passes through the roll stand, so that when a rolling abnormality occurs, it can be detected immediately.

Further, in the rolling abnormality detecting device according to the present invention, in the above configuration, the allowable range of the rolling retention force value in the comparison unit is a fixed ratio with respect to the rolling retention force value when passing through each roll stand. It is provided. By doing so, it is possible to detect which roll stand the rolling abnormality has occurred when passing.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a retention force calculating device and a rolling abnormality detecting device according to the present invention will be described below with reference to FIGS. FIG. 1 shows a schematic configuration of a rolling abnormality detection device equipped with a retention force calculation device of the present invention. FIG. 2 shows the displacement of the rotation speed and torque current value of the drive motor of the mandrel bar in the rolling process in the mandrel mill. FIG. 3 shows a state of displacement of the torque current value in the retention force calculation device and the rolling abnormality detection device of the present invention.

In FIG. 1, S is a mandrel mill, P is a hollow shell as a rolled material, B is a mandrel bar, and 1 is a mandrel mill S provided with equipment for holding the mandrel bar B, for example. This is a rolling abnormality detection device equipped with a retention force calculation device 11 which is configured as follows.

Reference numeral 2 denotes a bar retainer for holding the hollow shell P into which the mandrel bar B is inserted and transporting the hollow shell P to the mandrel mill S. The bar retainer 2 includes a bar retainer drive motor 2A and a reduction gear 2B as drive sources, and a bar retainer Drive wheel 2 rotated by the driving force of drive motor 2A
C, a driven wheel 2D provided at a position separated from the driving wheel 2C by a predetermined distance, and a chain 2E bridged over the driving wheel 2C and the driven wheel 2D.
A latch 2F is attached to the chain 2E and holds the mandrel bar B.

Reference numeral 3 denotes a bar retainer drive device which is a variable speed power supply for the bar retainer drive motor 2A in the bar retainer 2.
Performs the speed control of the bar retainer drive motor 2A according to a preset speed program, and outputs a torque calculation value T1 when the bar retainer drive motor 2A is driven to a retention force calculation device 11 described later.

Reference numeral 4 denotes a comparison unit for comparing a rolling retention force value F output from a retention force calculating device 11 described later with a preset allowable value. Reference numeral 5 denotes a determination unit that determines whether there is a rolling abnormality based on the comparison result output from the comparison unit 4.

The retention force calculating device 11 mounted on the rolling abnormality detecting device 1 having the above-described configuration is configured as follows.

An inertia torque (hereinafter referred to as an acceleration / deceleration torque Ta) accompanying acceleration / deceleration of the bar retainer drive motor 2A is calculated from the calculated torque value T1 output from the bar retainer drive device 3 as shown in the following equation (1). A first method for calculating the load torque T by subtracting and removing the acceleration / deceleration torque Ta
It is an operation unit.

[0026]

T = T1−Ta where T: load torque T1: calculated torque Ta: acceleration / deceleration torque

The load torque T calculated by the first calculation unit 11A, when output from the first calculation unit 11A, is equal to the torque TB corresponding to the mechanical loss to the torque TL used for rolling.
Is included, it can be expressed as in the following Expression 2.

[0028]

T = TL + TB where TL: torque for rolling TB: torque for mechanical loss

As shown in the following equation 3, the load torque T calculated by the first calculation unit 11A is
The value obtained by multiplying the constant obtained from the ratio of the reduction gear ratio inherent in B and the radius of the drive wheel 2C to the torque applied to the bar retainer drive motor 2A when the rolled material passes through each roll stand of the mandrel mill S. This is a second calculating unit that calculates the retained force value F1. The retention force value F1 calculated by the second calculation unit 11B is output to a lock-on calculation unit 11D and a rolling retention force calculation unit 11E described later.

[0030]

F1 = T × (i / R) where F1: Retained force value i: Reduction gear ratio R: Drive wheel radius

Incidentally, the retention force value F1 can also be expressed as the following equation 4 based on the above equation 2.

[0032]

F1 = (TL + TB) × (i / R)

Reference numeral 11C denotes an immediately before biting detection unit for detecting the timing immediately before the rolled material is bitten into the first roll stand of the mandrel mill S, and a signal immediately before biting is a lock-on calculation unit 11D described later. Is output to

When the signal immediately before biting is input from the biting detection unit 11C, the second arithmetic unit 11D
While storing the retained force value F1 input from B,
As shown in the following Expression 5, the stored retention force value F
This is a lock-on calculation unit that calculates a retention force value F0 immediately before biting from which the torque TL to be used for rolling has been removed from 1 and outputs it to a rolling retention force calculation unit 11E described later.

[0035]

F0 = TB × (i / R) * TL = 0, where F0 is the retention force immediately before biting

The mandrel 11E is calculated from the retention force value F1 output from the second operation unit 11B and the immediately preceding engagement retention force value F0 output from the lock-on operation unit 11D as shown in the following Expression 6. A rolling retention force calculation unit that calculates a true torque applied to the bar retainer drive motor 2A as a rolling retention force value F every time the mill S passes through each roll stand. This rolling retention force calculation unit 11
The rolling retention force value F from E is output to the comparison unit 4 of the rolling abnormality detection device 1.

[0037]

F = F1-F0 where F: rolling retention force value

The rolling retention force value F is equal to the acceleration / deceleration torque Ta.
And a variable which is irrelevant to rolling, such as torque TB for machine loss, that is, a bar retainer driving motor 2A provided when a rolled material passes (rolls) through each roll stand. Of torque. In addition,
The rolling retention force value F can also be expressed by transforming the above-described formulas 1 to 4 and transforming it into the following formula 7.

[0039]

F = {(T−TB) × i} / R = TL × (i / R)

Next, the retention force calculating device 11 having the above configuration
The rolling abnormality detection operation of the rolling abnormality detection device 1 equipped with the above will be described.

The mandrel bar B extends through the hollow shell P in the axial direction. The rear end of the mandrel bar B is attached to the latch 2F, and the driving wheel 2C is driven by the bar retainer driving motor 2A via the reduction gear 2B to move the latch 2F on the chain 2E in the driven wheel 2D direction. , The mandrel bar B moves. Then, the mandrel bar B moves to penetrate the hollow shell P, and the hollow shell P in this state is inserted into the mandrel mill S.

The bar retainer driving motor 2A is driven by the bar retainer driving device 3 based on a predetermined speed program so as to match the speed program. Changes in general rotation speed and torque current value of the bar retainer drive motor 2A when rolling is performed by the mandrel mill S are as shown in FIGS. 2 (a) and 2 (b).

As shown in FIG. 2 (a), the time A until the hollow shell P is bitten by the first roll stand of the mandrel mill S, and the hollow shell P passes through the final roll stand of the mandrel mill S The time C after the completion of the rolling is that the rotation speed is increased and the driving torque is changed. At the time B during rolling, the rotation speed and the torque are kept constant.

Here, the torque of the bar retainer drive motor 2A is shown in FIG. 3 by the calculation result of the retention force calculation device 11 of the present invention. The behavior of FIG. 2 (b) and the behavior of FIG. 3 are similar in the time A and time C regions.
Since the hollow shell P has not passed through the roll stand, that is, the retention force value F0 immediately before biting has not acted,
This is because the behavior of the retention force value F1, which is continuously calculated and output from the rolling retention force calculation unit 11E as needed, is reflected as it is.

Accordingly, within the time B region in which the hollow shell P passing through the mandrel mill S has a constant speed, the hollow shell P
Passes through multiple roll stands sequentially from the entry side,
According to the calculation result of the retention force calculation device 11 of the present invention shown in FIG. 3, during normal rolling, as shown by the solid line in FIG.
Until the tip of the hollow shell P passes through the final roll stand of the mandrel mill S, the hollow shell P is
Is drawn in from the entrance side to the exit side,
Until the tail end of the hollow shell P passes through the final roll stand of the mandrel mill S, the behavior increases stepwise.

That is, for example, immediately before the hollow shell P is bitten by the first roll stand, the lock-on operation unit 11D
Outputs the retention force value F0 immediately before biting from the hollow shell P.
Is caught in the first roll stand, the retention force value F0 immediately before the engagement is subtracted from the rolling retention force value F, so that the rolling retention force value F becomes smaller than the retention force value F1 calculated so far. , As shown in FIG.

Then, for example, after the hollow shell P has been bitten into the first roll stand and before proceeding to the next roll stand, the rolling retention force value F (F1-F0) unless a rolling abnormality occurs. Is substantially constant, and becomes substantially flat as shown in FIG. Such a behavior is repeated every time the vehicle passes through each roll stand.

In the abnormal rolling detection device 1, the comparison unit 4
A permissible value is provided for the rolling retention force value F as shown by the one-dot chain line, and the permissible value is provided at a constant ratio with respect to the rolling retention force value calculated when passing through each roll stand, for example. The rolling condition is monitored.

Here, the hollow shell P is partially compressed between certain roll stands and becomes wrinkled, causing an excessive rolling reaction force on the hollow shell P passing through the roll stand. When a rolling abnormality occurs such that the thin-walled rolling tear occurs due to excessive tension and the hollow shell P is not drawn into the exit side of the mandrel mill S, in any case, as shown by the broken line in FIG. The retention force value F sharply increases.

When the comparison unit 4 determines that a rolling abnormality has occurred and the rolling retention force value F has exceeded the permissible value indicated by the one-dot chain line in FIG. 3, a signal to that effect is output to the determination unit 5. . When a signal indicating that the rolling retention force value F has exceeded the allowable value is input, the determining unit 5 determines that a rolling abnormality has occurred, and performs control to immediately stop the equipment.

As described above, the retention force calculating device 11
From the driving torque and acceleration / deceleration torque of the bar retainer driving motor 2A and the torque immediately before rolling that is not used for rolling, the true value for rolling varies every time the hollow shell P passes through the roll stand of the mandrel mill S. Is calculated as the rolling retention force value F, so that the rolling behavior can be grasped reliably and in detail.

Then, the above-mentioned retention force calculating device 11
Is mounted on the rolling abnormality detecting device 1, the rolling abnormality can be detected reliably and early, and the equipment stoppage can be determined in the initial stage in which the rolling abnormality has occurred. Accordingly, it is possible to prevent the equipment in the mandrel mill S from being damaged, and to prevent a problem occurring in the hollow shell P, thereby minimizing damage and loss of downtime.

In addition, the rolling abnormality detecting device 1 includes a hollow shell P
The rolling retention force value F fluctuates each time the roll stand passes, so if it is provided at a fixed ratio with respect to the rolling retention force value when passing through each roll stand, which roll stand has occurred when passing It is possible to make a judgment and to perform the treatment promptly.

In addition to the above, the allowable value may be set as an average value of a fixed ratio in the regenerative direction in accordance with the behavior of the actual rolling retention force value F, for example. Although it is not possible to detect whether a rolling abnormality has occurred at the time of passing through the stand, it is possible to detect the rolling abnormality much faster and more accurately than in the past.

[0055]

As described above, in the retention force calculation device of the present invention, the calculation unit constantly calculates the retention force value of the motor, and the signal immediately before the rolled material is caught in each roll stand is input. Along with storing the retention force value at the time, the torque corresponding to the mechanical loss is removed from the stored retention force value to calculate and output the retention force value immediately before biting,
Since the rolling retention force value is calculated from the retention force value constantly calculated and the retention force value immediately before biting, the true torque of the motor when passing through each roll stand is monitored as the rolling retention force value. The behavior of the motor can be grasped in detail and properly.

Further, the rolling abnormality detecting device of the present invention comprises: a retaining force calculating device of the present invention; a comparing section for comparing a rolling retention force value calculated by the retaining force calculating device with a preset allowable value; Since a judgment unit for detecting a rolling abnormality based on the judgment of the comparison unit is provided, it becomes possible to detect the rolling abnormality reliably and early each time rolling is performed at each roll stand, and therefore, the rolling abnormality can be detected. In addition to minimizing equipment damage due to the occurrence, it is possible to minimize and minimize loss of downtime such as stoppage due to generation of torn material.

Further, in the rolling abnormality detecting device of the present invention, the allowable range provided for the rolling retention force value in the comparison unit is provided at a fixed ratio with respect to the rolling retention force value when passing through each roll stand. Further, it is possible to detect which roll stand the rolling abnormality has occurred when passing, and it is possible to promptly take a measure when the rolling abnormality occurs.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a rolling abnormality detecting device of the present invention equipped with a retention force calculating device of the present invention.

FIG. 2A is a diagram illustrating a displacement of a rotation speed of a motor driving a mandrel bar, and FIG. 2B is a diagram illustrating a displacement of a torque of a motor driving a mandrel bar.

FIG. 3 is a diagram for explaining a setting state of an allowable value and a rolling abnormality detection state in the retention force calculating device of the present invention and the rolling abnormality detecting device of the present invention.

FIG. 4 is a diagram for explaining a conventional method for detecting a rolling abnormality from a torque current value of a motor that drives a mandrel bar.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rolling abnormality detection device 2 Bar retainer 2A Bar retainer drive motor 2B Reduction gear 2C Drive wheel 3 Bar retainer drive device 4 Comparison unit 5 Judgment unit 11 Retained force calculation device 11A 1st calculation unit (calculation unit) 11B 2nd calculation unit (calculation unit 11C Detection unit immediately before biting 11D Lock-on operation unit 11E Rolling retention force operation unit B Mandrel bar S Mandrel mill P Hollow shell

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B21B 37/78 B21B 37/00 128B B21C 51/00

Claims (3)

[Claims] 1. A retention force calculation device for calculating a torque of a motor for feeding a rolled material to a plurality of roll stands of a mandrel mill as a retention force value each time the roll material passes through each roll stand of the mandrel mill. A calculation unit for calculating a retention force value from a torque calculation value calculated from the driving torque of the driving machine and an acceleration / deceleration torque of the driving mechanical system; A signal immediately before biting from the biting detection unit and a signal just before biting is output from the biting detection unit. A lock-on calculation unit for calculating a retention force value immediately before biting by removing a torque component; a retention force value output from the calculation unit; A rolling force calculation device comprising: a rolling retention force calculation unit that calculates a rolling retention force value from a retention force value immediately before biting output from a calculation unit and a rolling retention force value. 2. The retention force calculating device according to claim 1,
A comparison unit that compares the rolling retention force value calculated by the retention force calculation device with a preset allowable range of the rolling retention force value, and determining whether the rolling state is good or bad based on the comparison result by the comparison unit. And a rolling abnormality detecting device. 3. The rolling abnormality detecting apparatus according to claim 2, wherein the allowable range of the rolling retention force value is set at a fixed ratio to the rolling retention force value when passing through each roll stand. apparatus.