Rolling mill safety pin fatigue online monitoring method and system

Abstract

The invention discloses a rolling mill safety pin fatigue on-line monitoring method and system. The method comprises the steps that the actual rotating speed and the actual load torque of a main transmission motor are sampled according to a set sampling period in the rolling state; calculating the rotating speed change rate of the main transmission motor at the current sampling moment and the actual output torque of the active motor at the current sampling moment; and performing fatigue detection on the safety pin based on the rotating speed change rate of the main transmission motor at the current sampling moment, the actual load torque of the main transmission motor and the actual output torque of the driving motor. The fatigue state of the safety pin is detected on line, and a replacement prompt is sent to the safety pin in the fatigue state in time, so that the risk of rolling interruption caused by breakage of the safety pin is greatly reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of universal rolling mill safety protection, and more specifically, relates to a rolling mill safety pin fatigue online monitoring method and system. Background Art

[0002] For continuous rolling mills, most of the safety pin breakage accidents of the rolling mill transmission mechanism occur when the rolling mill is subjected to instantaneous large load impact. This is why the rolling mill transmission mechanism is equipped with safety pin protection. However, due to fatigue problems, the safety pin of the rolling mill transmission mechanism may break during the rolling process even without instantaneous large load impact.

[0003] Application number: 2012100352459, patent name: Online monitoring method for the status of the safety pin of the rolling mill transmission mechanism, which comprehensively monitors the online status of the safety pin, and monitors online whether the safety pin is cut when it should be cut, is not cut when it should be cut, is cut when it should not be cut, or is cut beyond the limit shear torque.

[0004] The above scheme mainly performs online detection on broken (sheared) safety pins. The safety pins are located between the motor and the reducer. The torque generated by the motor is transmitted to the reducer, and then to the rollers through the reducer, driving the rollers to rotate, thereby causing the rolled piece to be deformed by rolling between the rollers. When the safety pin breaks, the rolling process is interrupted. Summary of the Invention

[0005] The present invention provides an online monitoring method for fatigue of safety pins of a rolling mill, which reduces the risk of rolling interruption by online identifying safety pins in a fatigue state and replacing them in a timely manner.

[0006] The present invention is implemented as follows: a method for online monitoring fatigue of a rolling mill safety pin, the method being specifically as follows:

[0007] (1) Under the rolling state, the actual speed and actual load torque of the main drive motor are sampled at a set sampling period Δt;

[0008] (2) Calculate the speed change rate of the main drive motor at the current sampling moment and the actual output torque of the active motor at the current sampling moment;

[0009] (3) Based on the speed change rate of the main drive motor at the current sampling moment, the actual load torque of the main drive motor and the actual output torque of the active motor, the fatigue detection of the safety pin is performed respectively.

[0010] Furthermore, the safety pin fatigue state detection method is as follows:

[0011] (31) Detect the current speed change rate Δn of the main drive motor i / Δt is greater than a second speed change rate threshold value. If the detection result is yes, it is determined that the safety pin is currently in a fatigue state. If the detection result is no, step (32) is executed;

[0012] (32) Detect the speed change rate Δn of the main drive motor i Whether / Δt is greater than a set first speed change rate threshold, if the detection result is yes, the counter updates the count and executes step (33);

[0013] (33) Check whether the current count DNDT_C of the counter is greater than the set upper limit of the count. If the test result is yes, it is determined that the safety pin is in a fatigue state;

[0014] Among them, the second speed change rate threshold is set based on the speed change rate of the main drive motor under the impact force that causes damage to the safety pin, and the first speed change rate threshold is set according to the actual speed change rate of the rolling mill active drive motor when the rolled piece is bitten, and the second speed change rate threshold is greater than the first speed change rate threshold.

[0015] Furthermore, the safety pin fatigue state detection method is as follows:

[0016] Detect the actual load torque value T of the main drive motor at the current sampling moment Li Whether the set load torque threshold is reached. If the detection result is yes, it is determined that the safety pin is currently in a fatigue state;

[0017] The load torque threshold of the main drive motor is set based on the load torque value of the main drive motor when the rolling mill is stuck.

[0018] Furthermore, the safety pin fatigue state detection method is as follows:

[0019] Detect the actual output torque T of the main drive motor at the current sampling moment di Is it greater than the set output torque threshold? If the test result is yes, it is determined that the safety pin is currently in a fatigue state;

[0020] The output torque threshold is set based on the output torque of the main drive motor under the impact force that causes damage to the safety pin.

[0021] Furthermore, when the safety pin is detected to be in a fatigue state, a safety pin replacement prompt is issued.

[0022] Furthermore, after the replacement of the safety pin is completed based on the full pin replacement prompt, the count DNDT_C of the counter is reset to zero.

[0023] Furthermore, the actual output torque T of the active motor at the current sampling moment is di The calculation formula is as follows:

[0024] T di =T Li +GD 2 / 375×Δn i / Δt;

[0025] Among them, GD 2 Δn is the flywheel inertia converted from the rolling mill transmission mechanism to the output shaft of the main drive motor. i It is the actual speed change of the main drive motor from the last sampling time to the current sampling time.

[0026] Furthermore, if the safety pin in normal condition breaks, a safety pin quality problem prompt will be issued.

[0027] The present invention is implemented as follows: an online monitoring system for fatigue of a rolling mill safety pin, the system comprising:

[0028] An acquisition unit, a storage unit connected to the acquisition unit, a processing unit connected to the storage unit, and a prompting unit connected to the processing unit;

[0029] The acquisition unit periodically samples the actual speed and actual load torque of the main drive motor in the rolling state, and sends them to the storage unit and the processing unit respectively; the storage unit stores the actual speed and actual load torque of the main drive motor at the current sampling moment and the previous sampling moment, and sends them to the processing unit. The processing unit detects whether the safety pin is currently in a fatigue state based on the above-mentioned rolling mill safety pin fatigue online monitoring method. If the detection result is yes, a safety pin replacement prompt is issued through the prompt unit.

[0030] The present invention detects the fatigue state of the safety pin online and issues a replacement reminder in time to the safety pin in the fatigue state, thereby greatly reducing the risk of rolling interruption caused by the breakage of the safety pin. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A flow chart of a method for online monitoring fatigue of a rolling mill safety pin provided by an embodiment of the present invention;

[0032] Figure 2 A schematic structural diagram of the rolling mill safety pin fatigue online monitoring system provided in this embodiment;

[0033] Figure 3 Waveform diagram of the speed, speed change rate, and load torque ratio of the main drive motor provided in an embodiment of the present invention

[0034] Figure 4 A waveform diagram showing the changes in the speed, speed change rate, number of load impacts, load torque ratio, and output torque ratio of the main drive motor provided in an embodiment of the present invention;

[0035] Figure 5 This is a waveform diagram of the speed change rate and counter count of the main drive motor provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0036] The specific implementation methods of the present invention will be further explained in detail below by describing the embodiments with reference to the accompanying drawings, so as to help those skilled in the art to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the present invention.

[0037] Figure 1 This is a flow chart of a method for online monitoring of fatigue of a rolling mill safety pin provided by an embodiment of the present invention. The method is specifically as follows:

[0038] (1) Under the rolling state, the actual speed and actual load torque of the main drive motor are sampled at a set sampling period Δt;

[0039] The motor that provides power to the rollers in the rolling mill transmission mechanism samples the actual speed and load torque of the main drive motor of the rolling mill at a set sampling period Δt in the rolling state, and stores the actual speed n of the main drive motor at the current sampling moment. i , the actual speed n of the main drive motor at the last sampling moment i-1 , the actual load torque T of the main drive motor at the current sampling moment Li And the actual load torque T of the main drive motor at the last sampling moment Li-1 .

[0040] (2) Calculate the speed change rate of the main drive motor at the current sampling moment and the actual output torque T of the active motor at the current sampling moment di ;

[0041] In the embodiment of the invention, the speed change rate of the main drive motor at the current sampling moment is the actual speed change rate Δn of the main drive motor during the period from the previous sampling moment to the current sampling moment. i / Δt, the actual output torque T of the active motor at the current sampling moment di The calculation formula is as follows:

[0042] T di =T Li +GD 2 / 375×Δn i / Δt;

[0043] Among them, GD 2 is the moment of inertia of the rolling mill (the flywheel inertia of the entire transmission mechanism of the rolling mill converted to the output shaft of the motor), Δn i The actual speed change of the main drive motor from the last sampling time to the current sampling time, that is, Δni =n i -n i-1 .

[0044] (3) Based on the speed change rate of the main drive motor at the current sampling moment and the actual load torque value T of the main drive motor Li And the actual output torque T of the active motor di Conduct fatigue testing of safety pins separately;

[0045] In an embodiment of the present invention, a method for detecting the fatigue state of a safety pin based on the speed change rate of the main drive motor at the current sampling moment is specifically as follows:

[0046] (31) Detect the current speed change rate Δn of the main drive motor i / Δt is greater than a second speed change rate threshold value. If the detection result is yes, it is determined that the safety pin is currently in a fatigue state. If the detection result is no, step (32) is executed;

[0047] (32) Detect the speed change rate Δn of the main drive motor i / Δt is greater than the set first speed change rate threshold value. If the detection result is yes, the counter updates the count DNDT_C=DNDT_C+1 and executes step (33). If the detection result is no, it is determined that the safety pin is currently in a normal state;

[0048] (33) Check whether the current count DNDT_C of the counter is greater than the set count upper limit value (5000). If the test result is yes, it is determined that the safety pin is in a fatigue state. If the test result is no, it is determined that the safety pin is currently in a normal state.

[0049] In the embodiment of the present invention, the second speed change rate threshold is set based on the speed change rate of the main drive motor under the impact force that causes damage to the safety pin. As long as it is detected that the speed change rate of the main drive motor reaches the second speed change rate threshold (1800 rpm / s), it is determined that the safety pin is currently in a fatigue state. Figure 3 The red dot in the waveform of the speed change rate of the main drive motor shows that the speed change rate reaches 2100 rpm / s. At this time, the safety pin is considered to be in a fatigue state. The first speed change rate threshold is set according to the actual speed change rate of the rolling mill active drive motor when the rolled piece is bitten. Therefore, the speed change rate of the main drive motor Δn i The situation where / Δt is greater than the first speed change rate threshold (500rpm / s) basically occurs when the workpiece bites. This is also the moment when the rolling mill is subjected to the greatest impact load during the rolling of a steel billet. If the safety pin experiences a large number of heavy load impacts for a long time, the safety pin may be damaged due to the impact load. Therefore, in the actual speed change rate Δn of the drive motor, iWhen / Δt is greater than the first speed change rate threshold, counting is performed. When the count value reaches the set number of times threshold, it is determined that the safety pin is in a fatigue state. Figure 4 The red point in the speed change rate waveform of the main drive motor in the figure, at this time the speed change rate of the main drive motor reaches 1400rpm / s, which is greater than the first speed change rate threshold and less than the second speed change rate threshold. The current counter updates the count DNDT_C = DNDT_C+1.

[0050] In the embodiment of the present invention, based on the actual load torque T of the main drive motor at the current sampling moment Li The specific method for detecting the fatigue state of the safety pin is as follows:

[0051] Detect the actual load torque value T of the main drive motor at the current sampling moment Li Whether the set load torque threshold is reached. If the detection result is yes, it is determined that the safety pin is currently in a fatigue state;

[0052] The load torque threshold of the main drive motor is set based on the load torque value of the main drive motor when the rolling mill is stuck. It is also the maximum load torque that the main drive motor can withstand and is set to 161% of the rated load torque. Figure 3 The red dot in the load torque ratio waveform shows that the load torque of the main drive motor has reached 161% of the rated load torque at this time, and the safety pin is considered to be in a fatigue state. At the current sampling moment, the actual load torque T Li When the set load torque threshold is reached, it means that the rolling mill has stopped due to jamming. At this time, the safety pin is also under a very large load and is damaged. It is determined that the safety pin is currently in a fatigue state.

[0053] In the embodiment of the present invention, based on the actual output torque T of the main drive motor at the current sampling moment di The specific method for detecting the fatigue state of the safety pin is as follows:

[0054] Detect the actual output torque T of the main drive motor at the current sampling moment di Is it greater than the set output torque threshold? If the test result is yes, it is determined that the safety pin is currently in a fatigue state;

[0055] In the embodiment of the present invention, the output torque threshold is set based on the actual output torque of the main drive motor under the impact force that causes damage to the safety pin, and is generally set to 250% of the rated output torque. At the current sampling moment, the actual output torque T of the main drive motor is di When the output torque is greater than the set threshold, it means that the safety pin has been subjected to a very large impact force and is considered to be in a fatigue state. Figure 4The red dot in the output torque ratio waveform indicates that the output torque of the main drive motor accounts for 250% of the rated output torque. At this time, the safety pin is considered to be in a fatigue state. The load torque ratio indicates the ratio of the load torque of the main drive motor to the rated load torque.

[0056] (4) If the safety pin is currently in a fatigue state, a safety pin replacement reminder will be issued.

[0057] In the embodiment of the present invention, a safety pin in a fatigued state has a greater risk of breaking. Therefore, when the safety pin is detected to be in a fatigued state, a safety pin replacement prompt is immediately issued to prompt the staff to replace the safety pin. After the safety pin is replaced, the counter DNDT_C is reset to zero and the counting starts again. Figure 5 As shown, Figure 5 When the speed change rate of the main drive motor is greater than the first speed change rate threshold (500 rpm / s), at this moment, the count of the counter is +1.

[0058] The present invention detects the fatigue state of the safety pin online and issues a replacement reminder in time to the safety pin in the fatigue state, thereby greatly reducing the risk of rolling interruption caused by the breakage of the safety pin.

[0059] (5) If the safety pin breaks when it is in a normal state, a safety pin quality problem prompt will be issued. Li And the actual output torque T of the main drive motor di When it is detected that the safety pin is currently in a normal state, that is, a non-fatigue state, in principle the safety pin can normally protect the rolling mill gearbox. However, if the safety pin still breaks at this time, it means that there is a problem with the quality of the safety pin, and the corresponding coupling, pin sleeve or safety pin needs to be checked and replaced.

[0060] Figure 2 The schematic diagram of the structure of the rolling mill safety pin fatigue online monitoring system provided in this embodiment shows only the parts related to the embodiment of the present invention for ease of explanation. The system includes:

[0061] An acquisition unit, a storage unit connected to the acquisition unit, a processing unit connected to the storage unit, and a prompting unit connected to the processing unit;

[0062] The acquisition unit periodically samples the actual speed and actual load torque of the main drive motor in the rolling state and sends them to the storage unit and the processing unit respectively;

[0063] The storage unit stores the actual speed and actual load torque of the main drive motor at the current sampling moment and the previous sampling moment, and sends them to the processing unit. The processing unit detects whether the safety pin is currently in a fatigue state based on the above-mentioned rolling mill safety pin fatigue online monitoring method. If the detection result is yes, a safety pin replacement reminder is issued through the prompt unit. By detecting the fatigue state of the safety pin online, a replacement reminder is issued in time for the safety pin in a fatigue state, thereby greatly reducing the risk of rolling interruption caused by safety pin breakage.

[0064] The present invention has been described exemplarily. Obviously, the specific implementation of the present invention is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the scope of protection of the present invention.

Claims

1. A rolling mill safety pin fatigue online monitoring method, characterized in that: The method is specifically as follows: (1) Under the rolling state, the actual speed and actual load torque of the main drive motor are sampled at a set sampling period Δt; (2) Calculate the speed change rate of the main drive motor at the current sampling moment and the actual output torque of the active motor at the current sampling moment; (3) Based on the speed change rate of the main drive motor at the current sampling moment, the actual load torque of the main drive motor and the actual output torque of the active motor, the fatigue detection of the safety pin is performed respectively.

2. The rolling mill safety pin fatigue online monitoring method according to claim 1, characterized in that: The specific method for detecting the fatigue state of the safety pin is as follows: (31) Detect the current speed change rate Δn of the main drive motor i / Δt is greater than a second speed change rate threshold value. If the detection result is yes, it is determined that the safety pin is currently in a fatigue state. If the detection result is no, step (32) is executed; (32) Detect the speed change rate Δn of the main drive motor i Whether / Δt is greater than a set first speed change rate threshold, if the detection result is yes, the counter updates the count and executes step (33); (33) Check whether the current count DNDT_C of the counter is greater than the set upper limit of the count. If the test result is yes, it is determined that the safety pin is in a fatigue state; Among them, the second speed change rate threshold is set based on the speed change rate of the main drive motor under the impact force that causes damage to the safety pin, and the first speed change rate threshold is set according to the actual speed change rate of the rolling mill active drive motor when the rolled piece is bitten, and the second speed change rate threshold is greater than the first speed change rate threshold.

3. The rolling mill safety pin fatigue online monitoring method according to claim 1, characterized in that: The specific method for detecting the fatigue state of the safety pin is as follows: Detect the actual load torque value T of the main drive motor at the current sampling moment Li Whether the set load torque threshold is reached. If the detection result is yes, it is determined that the safety pin is currently in a fatigue state; The load torque threshold of the main drive motor is set based on the load torque value of the main drive motor when the rolling mill is stuck.

4. The rolling mill safety pin fatigue online monitoring method according to claim 1, characterized in that: The specific method for detecting the fatigue state of the safety pin is as follows: Detect the actual output torque T of the main drive motor at the current sampling moment di Is it greater than the set output torque threshold? If the test result is yes, it is determined that the safety pin is currently in a fatigue state; The output torque threshold is set based on the output torque of the main drive motor under the impact force that causes damage to the safety pin.

5. The rolling mill safety pin fatigue online monitoring method according to claim 1, characterized in that: When the safety pin is detected to be in a fatigue state, a safety pin replacement reminder is issued.

6. The rolling mill safety pin fatigue online monitoring method according to claim 5, characterized in that: After completing the replacement of the safety pins based on the full pin replacement prompt, the count DNDT_C of the counter is reset to zero.

7. The rolling mill safety pin fatigue online monitoring method according to claim 1, characterized in that: The actual output torque T of the active motor at the current sampling moment di The calculation formula is as follows: T di =T Li +GD 2 / 375×Δn i / Δt; Among them, GD 2 Δn is the flywheel inertia converted from the rolling mill transmission mechanism to the output shaft of the main drive motor. i It is the actual speed change of the main drive motor from the last sampling time to the current sampling time.

8. The rolling mill safety pin fatigue online monitoring method according to claim 1, characterized in that: If a safety pin in normal condition breaks, a safety pin quality problem prompt will be issued.

9. An online monitoring system for fatigue of safety pins of rolling mills, characterized in that: The system comprises: An acquisition unit, a storage unit connected to the acquisition unit, a processing unit connected to the storage unit, and a prompting unit connected to the processing unit; The acquisition unit periodically samples the actual speed and actual load torque of the main drive motor in the rolling state, and sends them to the storage unit and the processing unit respectively; the storage unit stores the actual speed and actual load torque of the main drive motor at the current sampling moment and the previous sampling moment, and sends them to the processing unit. The processing unit detects whether the safety pin is currently in a fatigue state based on the online monitoring method for fatigue of the safety pin of the rolling mill according to any one of claims 1 to 8. If the detection result is yes, a safety pin replacement prompt is issued through the prompt unit.

Images