JPH09196650A - Method for diagnosing wear and deterioration od pinch roll - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simply diagnose wear and deterioration of a pinch roll without providing a detector by obtaining a load variable index of a driving system of the pinch roll and comparing the index with a predetermined threshold value. SOLUTION: A load variable index of a driving system (motor 3) of a pinch roll 1 is obtained, and index is compared with a predetermined threshold, thereby determining when to replace. The index is a variable index α in load current and is calculated from a fluctuation amount ΔI in load current when a metallic material (steel plate 2) is engaged with the pinch roll 1 and variable retention time Δt of the load current by an equation of α=A(constant)×ΔI/Δt. That is, by sampling data with engaging timing of the steel plate 2, the load variable index αof the motor 3 is obtained. When the result exceeds a predetermined reference value, a wear of the pinch roll 1 is determined to have reached a time for replacement. Thus wear and deterioration diagnosis of the pinch roll 1 can be effectively performed by using simple calculation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface wear state of a pinch roll that applies a rolling force to a metal material in a strip shape or a rod shape to rotate the roll-shaped rotating body to impart a conveying force or a tension to the metal material. The present invention relates to a method of diagnosing wear deterioration of pinch rolls for monitoring.

[0002]

2. Description of the Related Art Constant monitoring of pinch roll wear is an important factor for maintaining stable production. From the monitoring information, it is required that the pinch rolls are exchanged when necessary according to a predetermined pinch roll exchange standard so as not to cause a major failure or abnormal quality.

In order to meet such demands, in the field of paper transport technology, as a pinch roll wear deterioration diagnosis method, the paper transport distance is weighted according to the paper detection time and the paper transport speed. An invention (Japanese Unexamined Patent Publication No. 4-88446) that digitizes and accumulates the wear state based on the transport distance and outputs the accumulated value as wear determination information for paper transport, or a displacement gauge is directly installed on a roll-shaped rotating body. An invention (Japanese Patent Laid-Open No. 3187612) in which a displacement gauge is moved to measure roll wear by arithmetic processing has been proposed.

[0004]

However, the above-mentioned Japanese Patent Application Laid-Open No.
The invention described in JP-A-88446 is a paper in which an object is continuous, and if this technique is directly applied to the field of a strip-shaped or rod-shaped metal material targeted by the present invention, there is a problem in this field. The wear due to the impact of biting cannot be evaluated. Further, in Japanese Patent Application Laid-Open No. 3-186712, although the measurement is direct, a mechanism for installing and moving a displacement meter is required, and therefore a considerably high cost is required for implementation.

Therefore, the present invention makes it possible to easily evaluate the wear of pinch rolls, which is greatly affected by the wear due to the impact of biting, and to perform the wear deterioration diagnosis of the pinch rolls without using a special index or providing a detector. The purpose is to provide a method of doing so.

[0006]

In order to achieve the above object, the present invention provides a method for diagnosing wear deterioration of a pair of pinch rolls of the same diameter whose rotations are synchronized and which are involved in the conveyance of a strip-shaped or rod-shaped metallic material. It is characterized in that the load change index of the drive system of the pinch roll is obtained, and the replacement time is determined by comparing this index with a predetermined threshold value. Further, in the present invention, the index is a load current fluctuation index, and when the dimensions of the strip-shaped or rod-shaped metal material, the conveying speed, and the pinch roll rotation speed are constant, the metal material is caught in the pinch roll. The load current fluctuation amount ΔI and the load current fluctuation duration Δt are measured, and the load current fluctuation index α is calculated by α = A (constant) × ΔI / Δt.

According to the first aspect of the present invention, as the load variation in the pinch roll drive system, the pinch roll wear deterioration diagnosis is performed by measuring the axial strain of the drive system caused by the rotational speed variation of the roll and the torsional variation of the drive system. I do.
Generally, the pinch roll always waits at the set gap before the strip-shaped or rod-shaped metal material is caught.
A reaction force is generated from the metal material in the gap of the pinch rolls at the moment when the metal material is bitten, and the reaction force causes a frictional force between the pinch rolls and the metal material and a load torque. If the gap widens due to wear,
Since the reaction force generated becomes small, the load torque decreases.

According to the second aspect of the invention, as the load fluctuation in the drive system of the pinch roll, the fluctuation of the load current of the drive system is adopted, and the wear state is defined as the fluctuation index α of the load current. Since the torque fluctuation and the current fluctuation value of the prime mover of the pinch roll have a proportional relationship, the magnitude of the fluctuation of the load torque is determined by the current fluctuation value of the prime mover of the pinch roll in the present invention.

The present inventor investigated and examined what kind of current change of the pinch roll prime mover, which fluctuates depending on the change of the wear amount, should be used as an index. As a result, it was confirmed that if the load current variation index α in FIG. 4 is α = A (constant) × load current variation ΔI / load current variation duration Δt, the wear amount can be most remarkably expressed. Also in FIG.
The results obtained by investigating the relationship between the meandering amount of the metal material generated by pinch roll wear and the variation index α of the load current are shown.

The conditions for the dimensions of the strip-shaped or rod-shaped metal material, the conveying speed, and the number of rotations of the pinch roll are kept constant for the following reasons. That is, as shown in FIG. 6, the relationship between the actual pinch roll wear mode and the metal material is that the metal material may enter the recess due to wear and may cross the recess and the pinch roll during standby. This is because the number of revolutions varies depending on the size of the metal material, because each of the factors greatly disturbs the gradient of the load current.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the pinch roll is in a state of standing by at a constant number of rotations before biting the strip-shaped or rod-shaped metal material. The material width and the number of rotations of the pinch roll are obtained in advance as process data representing the operation state, and they are applied to the measurement conditions to judge whether wear deterioration diagnosis is possible. If the diagnosis is possible, data is collected at the biting timing of the strip-shaped or rod-shaped metal material, and the load variation index of the drive system is obtained. Then, when the result exceeds a preset reference value, it is determined that the wear state of the pinch roll has reached the replacement time.

[0012]

EXAMPLES The present invention will be described in detail below with reference to a steel sheet conveying process as an example. FIG. 1 is a flow chart showing a processing example of a method for diagnosing wear deterioration of a pinch roll according to the present invention, and FIG. 4 is an explanatory diagram showing a current change of a pinch roll to which the method of the present invention is applied.

The plate width, the rotational speed of the pinch roll 1 shown in FIG. 3, the speed of the steel plate 2 and the plate width shown in FIG. 3 are previously loaded as process data into the data collecting device 5 shown in FIG.
According to the diagnosis condition, it is determined whether or not the diagnosis is possible (S101). Under a no-load condition in which the steel plate 2 does not reach in a diagnosable state, the upper and lower pinch rolls maintain a constant gap. Further, in order to prevent the steel plate from rolling up when the front end of the steel plate is bitten, the pinch roll rotates at a rotational speed slightly higher than the speed at which the steel plate enters. At the moment when the tip of the steel plate 2 bites into the pinch roll 1 in this standby state, a reaction force due to the rolling reduction and a dynamic frictional force due to the difference between the plate speed and the pinch roll rotation speed are generated, causing torque fluctuations and The load current fluctuates in the current value of the motor 3 which is in a proportional relationship. This data is used for the tip detectors 4 and 8 installed in front of the pinch roll shown in FIG.
Is used as a trigger to collect (S102).

Next, in the arithmetic circuit 6, the load current fluctuation index α
Load current variation ΔI / load current variation duration Δt
Is calculated and the constant of proportionality A is multiplied to calculate the fluctuation index α of the load current (S103). Then, it is determined whether or not the calculated α has become a level near (or coincident with) the replacement reference α _L (S104). When it is determined that the replacement time has come, a warning is issued by the alarm device 7 so that the monitoring staff can recognize it (S105).

FIG. 5 is a chart showing the results of the respective examples when the method of the present invention was carried out. The horizontal axis represents the load current variation index α, the vertical axis represents the meandering amount [mm] of the steel plate caused by pinch roll wear, and the diagonal line at the position of the vertical axis 15 mm indicates bending when the steel plate is wound. It is a threshold value (if it is less than this, no bending occurs). In carrying out the present invention, α _L = 2 was set so as not to exceed this line. Further, the proportional constant A of current and wear was set to 11. From the results shown in FIG. 5, it was possible to achieve stable striping by eliminating the meandering of the steel plate by replacing the wear with α _L = 2 and changing the wear so as not to exceed the wear amount.

[0016]

According to the present invention, the wear deterioration of the pinch rolls can be effectively diagnosed by using a simple calculation formula, and the pinch rolls can be replaced appropriately. Is suppressed and high-level stable operation is secured. In addition, it becomes possible to extend the life of the pinch roll.

[Brief description of drawings]

FIG. 1 is a flow chart showing a processing example of a pinch roll wear deterioration diagnosing method according to the present invention.

FIG. 2 is a specific system configuration diagram showing a processing example of a wear deterioration diagnosing method.

FIG. 3 is an overall assembly diagram showing a positional relationship between a pinch roll and a steel plate shown as an example.

FIG. 4 is a load current fluctuation diagram at the moment when the pinch roll bites a strip-shaped or rod-shaped metal material.

FIG. 5 is a diagram showing an effect of the present invention and a plate meandering amount with respect to a load current fluctuation index and a control value α _L thereof.

FIG. 6 is a diagram showing a relationship between a wear mode of a roll and a strip-shaped or rod-shaped metal material.

[Explanation of symbols]

 1 Pinch Roll 2 Steel Plate 3 Motor 4 Tip Detector 5 Data Collection Device 6 Arithmetic Circuit 7 Alarm 8 Tip Detector

Claims (2)

[Claims] 1. In a method of diagnosing wear and deterioration of a pair of pinch rolls of the same diameter whose rotations are synchronized with each other and involved in the conveyance of a strip-shaped or rod-shaped metal material, a load fluctuation index of a drive system of the pinch roll is obtained, and this index is calculated. And a predetermined threshold value are compared with each other to determine the replacement timing, and a pinch roll wear deterioration diagnosis method. 2. The index is defined as a load current variation index, and when the size of the strip-shaped or rod-shaped metal material, the conveying speed, and the pinch roll rotation speed are constant, the metal material is caught in the pinch roll. 2. The pinch according to claim 1, wherein the load current fluctuation amount ΔI and the load current fluctuation duration Δt are measured, and the load current fluctuation index α is calculated by α = A (constant) × ΔI / Δt. Roll wear deterioration diagnosis method.