JPH0446650B2 - - Google Patents

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method and device for detecting abnormal vibrations in a cold rolling mill, and particularly relates to a method and device for detecting abnormal vibrations in a cold rolling mill. The present invention relates to a method and device for detecting abnormal vibrations in a rolling mill.

[Conventional technology]

In general, in cold rolling mills, a type of resonance phenomenon called chattering can occur due to surface damage to the back-up rolls, excessive or insufficient lubricity of rolling oil, fluctuations in strip surface temperature, etc. be.

This chattering phenomenon is a serious impediment to operations. If this chattering phenomenon occurs once, it will cause chatter marks, that is, horizontal striped thickness fluctuations with a pitch of several mm to several tens of mm on the board surface, and in severe cases. may even reach plate failure.

Therefore, when chattering begins to occur, it is necessary to take measures such as lowering the rolling speed within 1 to 2 seconds. If this action is delayed, it may lead to plate breakage or quality deterioration. Become. Therefore, detection of the chattering phenomenon is extremely important.

Conventionally, as a device for detecting chattering, for example, as shown in Japanese Patent Publication No. 52-2708,
By installing a vibration detector in the housing of the rolling mill or the choke of the back-up roll and detecting the frequency of occurrence of the output voltage exceeding a certain amplitude, the frequency of occurrence can be determined to a predetermined value. It has been proposed to detect the occurrence of chattering when the threshold is exceeded.

Also, as a device to detect other chattering,
As shown in Japanese Patent Publication No. 57-44408, vibrations of various parts of a rolling mill such as the rolling mill housing, upper and lower back-up roll jocks, upper and lower work roll jocks, drive motor gearbox, bearings, etc. are detected, and the acceleration or acceleration of the vibrations is detected. When the vibration energy exceeds a certain value, or when the vibration intensity and vibration energy exceed a certain value, an abnormality detection signal is issued, and if necessary, the periodicity of the vibration is analyzed and a specific period is detected. It has been proposed to detect the occurrence of chattering by emitting an abnormality detection signal when vibration occurs.

[Problem that the invention seeks to solve]

However, since the device proposed in Japanese Patent Publication No. 52-2708 does not detect only frequency components specific to chattering, vibrations in the rolling mill drive system are also likely to be erroneously detected. In addition, with this device, it is more effective to install a vibration detector in the chopper of the backup roll than to install it in the housing, but each time the backup roll is reassembled, the detector must be removed.
There is a problem in that the rolls need to be reattached, which makes the work of reassembling the rolls complicated.

Furthermore, the method for detecting abnormal vibrations proposed in Japanese Patent Publication No. 57-44408 also has the same problem as the above-mentioned device in that the work of changing the rolls when replacing them becomes complicated.

Furthermore, in any of the above cases, the timing at which abnormal vibration is detected and the timing at which chatter marks occur are almost the same, and therefore, by the time measures are taken to prevent chatter marks from occurring, chatter marks have already spread over a range of several tens of meters. There is a problem in that it is emitted.

[Purpose of the invention]

The present invention has been made in view of the above conventional problems, and is capable of predicting the occurrence of chatter marks caused by vibrations of a rolling mill, thereby preventing the occurrence of chatter marks. An object of the present invention is to provide a method and device for detecting abnormal vibrations of a machine.

[Means for solving problems]

The present invention, as illustrated in FIG.
The vibrations generated in the cold rolling mill during operation are captured as fluctuations in the front tension of the metal strip, and these tension fluctuations are converted into vibrations via an auxiliary roll installed at the entrance of the rolling mill, and the frequency of this vibration is adjusted to a predetermined level. The above object is achieved by emitting an abnormal vibration detection signal when the vibration is within the range.

Further, the present invention provides an abnormal vibration detection device for a cold rolling mill, which is provided on an auxiliary roll provided on the entry side of the cold rolling mill, and on an operation side bearing and a drive side bearing of this auxiliary roll. an integrator that integrates the output of either one of the vibration detectors, a bandpass filter that outputs a signal when the output value of this integrator is a predetermined value, and a bandpass filter that outputs a signal based on the output of this bandpass filter. an integrator for integrating the output of a vibration detector provided on the operation side bearing of the auxiliary roll; and an integrator provided on the drive side bearing of the auxiliary roll. The integrator integrates the output of the vibration detector, and the output values of both these integrators are compared, and when the difference between the output values is greater than or equal to a predetermined value, or when each output value is greater than or equal to a predetermined value, a signal is generated. The above object is also achieved by comprising a roll bearing abnormality alarm means that includes a comparator that outputs an output, and an alarm generator that issues an alarm based on the output of the comparator.

[Effect]

The present invention was made based on the following findings.

In FIG. 2, the tension fluctuation A of the strip and the vibration B of the rolling mill were measured at the same timing. As is clear from the figure, the tension in the strip begins to fluctuate approximately 1.2 seconds before vibration occurs in the rolling mill. In this way, it was discovered that rolling mill vibrations could be predicted by variations in the tension of the strip.

However, since the strip tension itself changes in various ways depending on operating conditions, it is difficult to immediately predict rolling mill vibration from strip tension fluctuations. Therefore, in the present invention, tension fluctuations are taken as vibrations of the auxiliary roll, and the tension fluctuations of the strip are converted into vibrations via this auxiliary roll, and abnormal vibrations are detected based on the frequency of this vibration.

Therefore, according to the present invention, fluctuations in the tension of the strip on the entrance side of the cold rolling mill are detected as vibrations of the auxiliary roll, so that the cold rolling mill can detect abnormal vibrations as a sign of the occurrence of chatter marks. can be detected earlier. Thereby, it is possible to prevent chatter marks from occurring, which would cause great operational losses.

Furthermore, according to the present invention, it is possible to detect an abnormality in the bearing of the auxiliary roll itself, thereby preventing malfunctions in detecting abnormal rolling mill vibration.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

In this embodiment, the present invention is implemented between the i-th stand 10 and the i+1-th stand 12, as shown in FIG. In addition, the code 14A in the figure,
14B is a housing, 16A to 16D are backup rolls, 18A to 18D are work rolls, 2
0 and 22 are deflector rolls installed between the i-th stand 10 and the +1-th stand 12, and 24
1 and 2 show tension meter rolls installed between the deflector rolls 20 and 22 to detect the tension of the strip 26, respectively. For convenience of explanation, only the tension meter roll 24 is shown in a perspective view.

As shown in FIG. 3, the abnormal vibration detection device 30 of this embodiment includes a vibration detection means 32, a roll bearing abnormality alarm means 34, and an abnormal vibration alarm means 36.

The vibration detecting means 32 includes vibration detectors 38A and 38B installed on both the operating side and drive side bearings of the tension meter roll 24.

The roll bearing abnormality alarm means 34 includes amplifiers 40A and 40B that amplify the vibration acceleration detection signals from the respective vibration detectors 38A and 38B, and the vibration acceleration signals amplified by the amplifiers 40A and 40B to detect the vibration velocity. Integrators 42A, 42 that convert into signals
B and each output signal of these integrators 42A, 42B, and when the difference between these output signals is greater than a set value, or when each output signal itself is greater than a set value, the tension meter roll 2
a comparator 44 that determines that the bearing No. 4 is abnormal;
An alarm generator 46 generates an alarm signal based on the roll bearing abnormality detection signal from the comparator 44.

The abnormal vibration alarm means 36 includes the amplifier 40
B, the integrator 42B, and a bandpass filter 48 that extracts only those within a predetermined frequency band from the vibration velocity signals from the integrator 42B.
An alarm level setting device that compares the output signal from the bandpass filter 48 with a preset constant value and outputs an abnormal vibration detection signal if the result of this comparison is greater than the set value N times in a row (N≧1). 5
0 and an alarm generator 52 that issues an alarm signal based on the abnormal vibration detection signal from the alarm level setter 50.
It is composed of.

Note that the bandpass filter 48 has a natural frequency of 100 to 200 hertz when chattering occurs, so it is set to 100 to 200 hertz.

Next, the operation of this embodiment will be explained.

Vibration detectors 38 installed on the operating side and drive side bearings of the tension meter roll 24, respectively.
The vibration acceleration detection signals from A and 38B are amplified by amplifiers 40A and 40B. The amplified vibration acceleration signal is converted from a vibration acceleration signal to a vibration velocity signal by integrators 42A and 42B. The vibration velocity signal from the integrator 42B is separated by a bandpass filter 48 into only necessary signals, and abnormal vibrations are detected by the alarm level setting 50. When abnormal vibration is detected, an alarm is issued by the alarm device 52, and at the same time,
Necessary measures will be taken to prevent chatter marks from occurring.

Further, the output signals of the integrators 42A and 42B are compared by a comparator 44, and when the difference between the comparison output signals is greater than a set value, or when the value of each output signal itself is greater than a set value, a roll bearing abnormality detection signal is generated. is output to the alarm generator 46. Thereby, it is possible to prevent malfunction of abnormal rolling mill vibration detection when the tension meter roll bearing itself is abnormal.

According to this embodiment, fluctuations in the tension of the strip 26 on the entrance side of the cold rolling mill are detected as vibrations of the tension meter roll 24, rather than detecting abnormal vibrations as a sign of chatter marks in the cold rolling mill. Can be detected early. Thereby, it is possible to prevent chatter marks from occurring, which would cause great operational losses.

In particular, in this embodiment, since the roll bearing abnormality alarm means 34 is provided, it is possible to prevent malfunction in the abnormal vibration detection of the rolling mill when the bearing itself of the tension meter roll 24 is abnormal.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to detect in advance the occurrence of chatter marks caused by the vibrations of a cold rolling mill, which has the advantage of being able to effectively prevent the occurrence of chatter marks. It has a good effect.

[Brief explanation of the drawing]

Fig. 1 is a flow chart showing the gist of the abnormal vibration detection method for a cold rolling mill according to the present invention, and Fig. 2 is a comparison of strip tension and housing vibration at the same timing to explain the principle of the present invention. FIG. 3 is a block diagram including a partial side view, showing an embodiment of the abnormal vibration detection device for a cold rolling mill according to the present invention. 10, 12...Rolling stand, 24...Tension meter roll, 32...Vibration detection means, 34
... Roll bearing abnormality alarm means, 36 ... Abnormal vibration alarm means, 38A, 38B ... Vibration detector.

Claims (1)

[Scope of Claims] 1. When a metal strip is cold rolled in a cold rolling mill, the vibrations generated in the cold rolling mill during operation are regarded as fluctuations in the forward tension of the metal strip, and this tension fluctuation is A method for detecting abnormal vibrations in a cold rolling mill, characterized in that the vibrations are converted into vibrations via an auxiliary roll installed on the inlet side of the machine, and an abnormal vibration detection signal is generated when the frequency of the vibrations is within a predetermined range. 2. An auxiliary roll installed on the entry side of the cold rolling mill, a vibration detector installed on the operating side bearing and a drive side bearing of this auxiliary roll, and integrating the output of either one of the vibration detectors. Abnormal vibration alarm means comprising an integrator, a bandpass filter that outputs a signal when the output value of the integrator is a predetermined value, and an alarm generator that issues an alarm based on the output of the bandpass filter. an integrator that integrates the output of a vibration detector provided on the operating side bearing of the auxiliary roll; an integrator that integrates the output of the vibration detector provided on the drive side bearing of the auxiliary roll; A comparator that compares the output values of the integrators and outputs a signal when the difference between the output values is greater than a predetermined value, or when each output value is greater than a predetermined value, and an alarm is issued based on the output of this comparator. An abnormal vibration detection device for a cold rolling mill, comprising: an alarm generator that emits an alarm; and a roll bearing abnormality alarm means comprising: