An online monitoring and early warning method for a variable working condition casting crane lifting mechanism

Abstract

The application discloses an online monitoring and early warning method for a variable working condition casting crane lifting mechanism, and the online monitoring is realized by respectively monitoring the working conditions of bearings and the working conditions of drum shaft couplings. The online monitoring and early warning method for the variable working condition casting crane lifting mechanism realizes the functions of data checking, record judging and the like of machine replacement point inspection, determines early warning rules and diagnosis models by using the device states, working conditions and the like of the variable working condition casting crane lifting mechanism and the accumulated operation and maintenance experience, finds problems early and removes faults, and provides the basis for fast positioning of fault points for maintenance personnel.

Description

Technical Field

[0001] This invention belongs to the field of special equipment monitoring and diagnosis technology, specifically relating to an online monitoring and early warning method for the lifting mechanism of a casting crane under variable working conditions. Background Technology

[0002] Casting cranes are important logistics and handling equipment in steel plants, mainly used for lifting molten high-temperature metals. Due to the harsh on-site environment, high temperature, and heavy dust, as well as the difficulty in inspecting the reducer itself and the difficulty in monitoring the equipment status, once a malfunction occurs, it will affect the smooth flow of steelmaking logistics and may lead to serious safety production accidents.

[0003] Inspection of speed reducers is time-consuming and labor-intensive: the maintenance time far exceeds the existing scheduled maintenance time, and disassembly and assembly are difficult. It requires drilling holes in the factory roof and equipping a dedicated mobile crane with a large lift for maintenance work. Because the lower housing of the speed reducer is directly welded to the main trolley steel structure of the crane, all inspections must be carried out on-site. Once the speed reducer bearings or gears fail, causing damage to the housing, on-site restoration is extremely difficult, and the operating accuracy of the repaired speed reducer will decrease significantly. Currently, when equipment personnel conduct regular speed reducer inspections, they mainly rely on their five senses for judgment, which is inaccurate, labor-intensive, and not conducive to long-term equipment management. It also fails to detect potential hazards and defects in the equipment in a timely manner, contradicting the advocacy of intelligent equipment management.

[0004] The condition of drum couplings is difficult to control: Because the coupling rollers are made directly of bearing steel with high hardness, while the inner and outer rings have lower hardness, severe wear will occur on the inner and outer rings after long-term use. The retaining rings may fail, and some dislodged rollers will generate significant axial force during operation, causing damage to the cover plate, and in severe cases, even failure of the cover plate connection. Since the worn parts are all inside the drum coupling, daily inspection is extremely difficult. Only complete disassembly can determine the condition of its internal components. However, disassembling and inspecting a single coupling is time-consuming and labor-intensive, requiring significant downtime and resulting in production losses. Current inspection methods include checking the wear indicator to determine the amount of wear on the inner and outer rings, checking for loose external bolts, and detecting abnormal noises during operation.

[0005] The invention application with application number CN201410216474.X discloses "a safety monitoring system and method for lifting machinery", which includes a crane, a computer and application tools. A fiber optic grating sensor is installed on the lower surface of the crane's main beam cover plate along the entire length of the main beam. A position sensor is installed on the operating device. A current sensor is connected to the control circuit; a phase sequence sensor is connected to the power circuit. Speed ​​sensors are installed between the motor and reducer of the trolley mechanism, the gantry mechanism, and the hoisting mechanism, and between the reducer and the motion device. The crane is also equipped with an equipment safety monitoring unit, which includes a safety device monitoring unit, a maintenance and inspection unit, a usage management unit, and a safety risk warning unit.

[0006] The invention application with application number CN201910966143.0 discloses "a monitoring system for the transmission system of the main hoisting of a casting crane", which includes a drum, a power system respectively located at both ends of the drum for synchronously driving the drum to rotate, and a monitoring system for monitoring the synchronicity of the power system. The power system is connected in sequence with a motor, a brake, and a reducer in the power transmission order. The monitoring system includes a speed sensor located between the motor and the brake, a current sensor located on the power supply cable of the motor, a vibration sensor located at the shaft of the ratchet and pawl mechanism, a data acquisition unit, an industrial computer, and a fault indication device. When a fault occurs, the fault indication device responds.

[0007] The invention application with application number CN201910312140.5 discloses "a system and method for safety monitoring and control of crane brakes", including: a data acquisition device, a transmission device, a PLC, a hoisting mechanism, and an alarm device; the data acquisition device is used to acquire the compression amount of the brake spring when the brake is released; the transmission device is used to send the acquired compression amount of the brake spring when the brake is released and the extension amount of the brake spring when the brake is engaged to the PLC; the PLC controls the hoisting mechanism to stop hoisting when the compression amount when the brake is engaged is equal to the sum of the limit compensation stroke and the lifting height of the push rod, and sends a preset alarm signal to the alarm device; the alarm device is used to alarm for severe brake pad wear. Summary of the Invention

[0008] To address the above problems, this invention provides an online monitoring and early warning method for the lifting mechanism of a casting crane under variable working conditions.

[0009] An online monitoring and early warning method for the lifting mechanism of a casting crane under variable working conditions, characterized in that:

[0010] The online monitoring is carried out by establishing separate monitoring of the operating status of the bearings and the operating status of the drum coupling.

[0011] According to the present invention, an online monitoring and early warning method for the lifting mechanism of a casting crane under variable working conditions is characterized in that:

[0012] The monitoring of bearing operating conditions includes: monitoring bearing temperature, monitoring bearing speed, monitoring bearing acceleration, and monitoring bearing impact value.

[0013] According to the present invention, an online monitoring and early warning method for the lifting mechanism of a casting crane under variable working conditions is characterized in that:

[0014] The monitoring of the drum coupling is carried out by establishing a monitoring system for the distance between the reducer and the drum.

[0015] According to the present invention, an online monitoring and early warning method for the lifting mechanism of a casting crane under variable working conditions is characterized in that:

[0016] The online monitoring is triggered by operating conditions and establishes a monitoring system based on the operating status of the bearings and the drum coupling under various operating conditions.

[0017] According to the present invention, an online monitoring and early warning method for the lifting mechanism of a casting crane under variable working conditions is characterized in that:

[0018] Multiple vibration measuring points are set on the motor, gearbox, and drum support bearing housing respectively. The monitoring of bearing temperature, bearing speed, bearing acceleration, and bearing impact value is achieved through the measurement and data upload and processing of temperature and vibration sensors set at each measuring point.

[0019] According to the present invention, an online monitoring and early warning method for the lifting mechanism of a casting crane under variable working conditions is characterized in that:

[0020] The monitoring of the distance between the reducer and the drum is achieved through the measurement and data uploading and processing of the distance sensor installed on the reducer body.

[0021] According to the present invention, an online monitoring and early warning method for the lifting mechanism of a casting crane under variable working conditions is characterized in that:

[0022] The aforementioned operating conditions are determined based on monitoring and judging the motor current or the lifting weight.

[0023] According to the present invention, an online monitoring and early warning method for the lifting mechanism of a casting crane under variable working conditions is characterized in that:

[0024] When the bearing temperature exceeds 60℃, a temperature abnormality alarm will be issued;

[0025] When the effective value of the bearing speed is greater than 4.5 mm / s, a speed abnormality alarm will be issued;

[0026] When the effective value of the bearing acceleration is greater than 2.5g, an acceleration abnormality alarm will be issued;

[0027] When the bearing impact value or envelope value is greater than 3, an abnormal bearing impact value alarm will be issued.

[0028] According to the present invention, an online monitoring and early warning method for the lifting mechanism of a casting crane under variable working conditions is characterized in that:

[0029] When the cumulative change in the measured axial distance is greater than 10mm,

[0030] or

[0031] When the difference between heavy-load and light-load conditions exceeds 5mm, an alarm for abnormality in the drum coupling is issued.

[0032] Heavy-duty operation: The crane lifts a ladle full of molten metal, at which point the lifting capacity reaches 100% of the rated lifting capacity;

[0033] Light load condition: The crane lifts an empty steel ladle, at which point the lifting capacity reaches 30% of the rated lifting capacity;

[0034] Empty hook: There is no load under the crane hook.

[0035] According to the present invention, an online monitoring and early warning method for the lifting mechanism of a casting crane under variable working conditions is characterized in that:

[0036] When establishing trigger conditions based on operating conditions according to weight monitoring, the specific details are as follows:

[0037] The PLC reads the weight and gear information and generates trigger signals for six working conditions: heavy load full speed up, heavy load full speed down, empty hook full speed up, empty hook full speed down, empty package full speed up, and empty package full speed down.

[0038] According to the present invention, an online monitoring and early warning method for the lifting mechanism of a casting crane under variable working conditions is characterized in that:

[0039] The working condition of heavy load and full speed ascent is determined by four limiting conditions: 100% speed, heavy load weight, lifting mechanism rising one gear, and lifting mechanism in four gears.

[0040] The heavy-load, full-speed descent condition is determined by four limiting conditions: 100% rotation speed, heavy load weight, descent of the hoisting mechanism by one gear, and hoisting mechanism in four gears.

[0041] The working condition of the empty hook rising at full speed is determined by four limiting conditions: 100% speed, no weight, the hoisting mechanism rising one gear, and the hoisting mechanism in four gears.

[0042] The working condition of the empty hook descending at full speed is determined by four limiting conditions: 100% speed, no weight, the hoisting mechanism descending one gear, and the hoisting mechanism in four gears.

[0043] The working condition of the empty package rising at full speed is determined by four limiting conditions: 100% rotation speed, empty package weight, lifting mechanism rising one gear, and lifting mechanism in four gears.

[0044] The working condition of the empty package descending at full speed is determined by four limiting conditions: 100% rotation speed, empty package weight, the hoisting mechanism descending one gear, and the hoisting mechanism in four gears.

[0045] The crane lifting mechanism has four speed levels, from low to high. In the PLC control signals: the lifting mechanism goes up or down by one level to determine the direction of travel, and the fourth level is used to determine the speed of the mechanism.

[0046] According to the present invention, an online monitoring and early warning method for the lifting mechanism of a casting crane under variable working conditions is characterized in that:

[0047] Online monitoring is based on the PLC settings for receiving, transmitting, and processing signals;

[0048] All signals are transmitted wirelessly, while all signals are received via wired transmission.

[0049] According to the present invention, an online monitoring and early warning method for the lifting mechanism of a casting crane under variable working conditions is characterized in that:

[0050] The warning information is displayed through a user-friendly interface.

[0051] The present invention provides an online monitoring and early warning method for the lifting mechanism of a casting crane under variable working conditions. This method enables the machine to replace point inspections in data checking, recording and judgment, etc. It uses multiple parameters such as the equipment status and working conditions of the lifting mechanism of the casting crane under variable working conditions, as well as the accumulated operation and maintenance experience, to determine the early warning rules and diagnostic models, so as to detect problems and eliminate faults as early as possible, and at the same time provide maintenance personnel with a basis for rapid fault location.

[0052] By installing vibration sensors on the reducer and drum bearing housing, and collecting data on motor current, temperature, and crane operating conditions, the transmission device of the lifting mechanism can be monitored online.

[0053] The signal transmission involved forms a wireless-wired-wireless data transmission structure, which eliminates the need for cable laying, prevents signal attenuation, and saves costs.

[0054] The working conditions determined by weight are more convenient and faster than those determined by current. By establishing the monitoring of the distance between the reducer and the drum, and comparing the changes in the distance between the drum and the reducer under different working conditions, the usage status of the drum coupling is monitored. The signal triggering conditions are extracted from the crane safety monitoring system, instead of using a high-speed shaft speed measuring device, which effectively avoids the interference of high temperature and dust conditions on the speed model, ensuring the reliability and safety of data extraction, and can also accurately determine the load status. Attached Figure Description

[0055] Figure 1 This is a simplified diagram of the system structure involved in the present invention;

[0056] Figure 2 This is a schematic diagram of the system architecture involved in the present invention. Detailed Implementation

[0057] The following is a detailed description of an online monitoring and early warning method for the lifting mechanism of a casting crane under variable working conditions, based on the accompanying drawings and specific embodiments of the present invention.

[0058] An online monitoring and early warning method for the lifting mechanism of a casting crane under variable working conditions.

[0059] The online monitoring is carried out by establishing separate monitoring of the operating status of the bearings and the operating status of the drum coupling.

[0060] in,

[0061] The monitoring of bearing operating conditions includes: monitoring bearing temperature, monitoring bearing speed, monitoring bearing acceleration, and monitoring bearing impact value.

[0062] in,

[0063] The monitoring of the drum coupling is carried out by establishing a monitoring system for the distance between the reducer and the drum.

[0064] in,

[0065] The online monitoring is triggered by operating conditions and establishes a monitoring system based on the operating status of the bearings and the drum coupling under various operating conditions.

[0066] in,

[0067] Multiple vibration measuring points are set on the motor, gearbox, and drum support bearing housing respectively. The monitoring of bearing temperature, bearing speed, bearing acceleration, and bearing impact value is achieved through the measurement and data upload and processing of temperature and vibration sensors set at each measuring point.

[0068] in,

[0069] The monitoring of the distance between the reducer and the drum is achieved through the measurement and data uploading and processing of the distance sensor installed on the reducer body.

[0070] in,

[0071] The aforementioned operating conditions are determined based on monitoring and judging the motor current or the lifting weight.

[0072] in,

[0073] When the bearing temperature exceeds 60℃, a temperature abnormality alarm will be issued;

[0074] When the effective value of the bearing speed is greater than 4.5 mm / s, a speed abnormality alarm will be issued;

[0075] When the effective value of the bearing acceleration is greater than 2.5g, an acceleration abnormality alarm will be issued;

[0076] When the bearing impact value or envelope value is greater than 3, an abnormal bearing impact value alarm will be issued.

[0077] in,

[0078] When the cumulative change in the measured axial distance is greater than 10mm,

[0079] or

[0080] When the difference between heavy-load and light-load conditions exceeds 5mm, an alarm for abnormality in the drum coupling is issued.

[0081] Heavy-duty operation: The crane lifts a ladle full of molten metal, at which point the lifting capacity reaches 100% of the rated lifting capacity;

[0082] Light load condition: The crane lifts an empty steel ladle, at which point the lifting capacity reaches 30% of the rated lifting capacity;

[0083] Empty hook: There is no load under the crane hook.

[0084] in,

[0085] When establishing trigger conditions based on operating conditions according to weight monitoring, the specific details are as follows:

[0086] The PLC reads the weight and gear information and generates trigger signals for six working conditions: heavy load full speed up, heavy load full speed down, empty hook full speed up, empty hook full speed down, empty package full speed up, and empty package full speed down.

[0087] in,

[0088] The working condition of heavy load and full speed ascent is determined by four limiting conditions: 100% speed, heavy load weight, lifting mechanism rising one gear, and lifting mechanism in four gears.

[0089] The heavy-load, full-speed descent condition is determined by four limiting conditions: 100% rotation speed, heavy load weight, descent of the hoisting mechanism by one gear, and hoisting mechanism in four gears.

[0090] The working condition of the empty hook rising at full speed is determined by four limiting conditions: 100% speed, no weight, the hoisting mechanism rising one gear, and the hoisting mechanism in four gears.

[0091] The working condition of the empty hook descending at full speed is determined by four limiting conditions: 100% speed, no weight, the hoisting mechanism descending one gear, and the hoisting mechanism in four gears.

[0092] The working condition of the empty package rising at full speed is determined by four limiting conditions: 100% rotation speed, empty package weight, lifting mechanism rising one gear, and lifting mechanism in four gears.

[0093] The working condition of the empty package descending at full speed is determined by four limiting conditions: 100% rotation speed, empty package weight, the hoisting mechanism descending one gear, and the hoisting mechanism in four gears.

[0094] The crane lifting mechanism has four speed levels, from low to high. In the PLC control signals: the lifting mechanism goes up or down by one level to determine the direction of travel, and the fourth level is used to determine the speed of the mechanism.

[0095] in,

[0096] Online monitoring is based on the PLC settings for receiving, transmitting, and processing signals;

[0097] All signals are transmitted wirelessly, while all signals are received via wired transmission.

[0098] in,

[0099] The warning information is displayed through a user-friendly interface.

[0100] Working process, principle and implementation examples

[0101] See Figure 1 , 2 The method and corresponding system involved in this invention are described below.

[0102] The monitoring and early warning methods established by the system described below can monitor data such as parameters of the crane's main gearbox, drum coupling, drum bearings, and motor in real time, enabling early detection and troubleshooting of problems. This provides a basis for maintenance strategies for the hoisting mechanism of the casting crane, ensuring the safe operation of the crane. The system collects signals such as speed, vibration, and temperature online, combining them with process parameters. The system analyzes the effective data, processes it through the acquisition module, and uploads the processed signals to the main control unit via the network, thus achieving comprehensive monitoring of the status of critical equipment. This reduces the operating costs of casting cranes, improves equipment reliability and efficiency, and has high practicality.

[0103] The system components described above are as follows:

[0104] Employing integrated electronic control and electrical (EIC) technology, the system consists of a signal acquisition unit (U1), a main control unit (U2), and a monitoring unit (U3). See details... Figure 1 .

[0105] 1.1 Signal Acquisition Unit (U1):

[0106] The acquisition unit is primarily responsible for signal acquisition and simple logical judgment.

[0107] Operating condition signals: The traction control system and the signal acquisition unit (U1) exchange data using the Modbus RTU communication protocol. The main data collected are: actual speed of the main hoist, lifting capacity, main hoist motor current, operating condition (full speed), three-phase temperature of the main hoist motor, temperature of the drive end of the main hoist motor, and temperature of the non-drive end of the main hoist motor.

[0108] The data acquisition unit classifies the mechanism's state into six operating conditions through logical judgment: heavy load full-speed ascent, heavy load full-speed descent, empty hook full-speed ascent, empty hook full-speed descent, empty ladle full-speed ascent, and empty ladle full-speed descent. Heavy load condition: The crane lifts a ladle filled with molten metal, reaching 100% of its rated lifting capacity. Light load condition: The crane lifts an empty ladle, reaching 30% of its rated lifting capacity. Empty hook: There is no load under the crane hook.

[0109] The crane lifting mechanism has four speed levels, from low to high. In the PLC control signals: the lifting mechanism goes up or down by one level to determine the direction of travel, and the fourth level is used to determine the speed of the mechanism.

[0110]

[0111] Vibration signal: Based on the layout of the reducer and motor, vibration measurement points are set in the main lifting mechanism, including the motor, reducer and drum support bearing seats. The basic principle is to set one vibration measurement point for each bearing seat position. The measurement points are connected to a wired signal acquisition unit (U1) to ensure the synchronization of data acquisition.

[0112] Triggering Method: Due to the intermittent operation of casting cranes with varying speeds and working conditions, continuous data collection over a long period would generate a large amount of useless data, easily causing data network congestion and a significant increase in server load. Furthermore, the numerous and indiscriminate data points make it difficult to discern the equipment's operational status. Therefore, trigger-based data collection is necessary: ​​by identifying the mechanism's state (there are 6 working conditions): heavy load full-speed ascent, heavy load full-speed descent, empty hook full-speed ascent, empty hook full-speed descent, empty ladle full-speed ascent, and empty ladle full-speed descent, different alarm thresholds are set for each working condition, allowing for the filtering of valid status data under different conditions.

[0113] 1.2 Main Control Unit (U2): This part mainly realizes the professional analysis and processing of the collected data by various monitoring disciplines, such as the processing of vibration signals, and can also configure processing rules for the acquired process data.

[0114] The various types of data collected and analyzed on the main control unit are packaged by the data communication module according to the communication interface specifications and pushed to the monitoring and early warning unit (U3) in real time.

[0115] 1.3 Monitoring and Early Warning Unit (U3): Composed of servers and network equipment, it classifies, analyzes and stores data, and analyzes effective data to realize intelligent online monitoring of the status of the hoisting mechanism of the casting crane.

[0116] Function list of the equipment condition monitoring system for the hoisting mechanism of casting crane

[0117]

[0118] Enables remote real-time monitoring and automatic alarm for anomalies:

[0119] It offers multiple warning types, including vibration temperature exceeding the limit warning, vibration temperature remaining unchanged warning, sensor failure warning, and no data warning; at the same time, the threshold can be customized according to customer needs.

[0120] The specific explanation is as follows:

[0121] 1) Vibration temperature exceeding the standard warning:

[0122] It performs real-time monitoring on a sensor-by-sensor basis, and issues an alarm when vibration or temperature data exceeds a threshold; customers can customize the vibration or temperature threshold settings.

[0123] 2) Sensor fault early warning:

[0124] Real-time monitoring is performed on a sensor-by-sensor basis. When abnormal values ​​are detected in the sensor data feedback, an alarm is triggered to prompt the customer to troubleshoot the problem.

[0125] 3) No data alert:

[0126] It performs real-time monitoring on a sensor-by-sensor basis, and issues an alarm when no sensor data is transmitted, prompting the customer to troubleshoot the problem.

[0127] 4) Warning details page:

[0128] Users can click to view individual warning details, including warning location, warning type, warning time, severity, recovery status, current threshold setting, and anomaly value legend. This helps users understand temperature anomalies and promptly investigate and restore order. Inspection personnel can perform operations on this page, provide feedback on inspection results, and determine whether an alarm is false.

[0129] Data report visualization

[0130] It provides a variety of data reports, including statistics on excessive temperature, excessive vibration, excessive rotational speed, excessive displacement, sensor failure, and management statistics, to help customers improve management efficiency.

[0131] Threshold Custom Configuration

[0132] The threshold customization feature allows customers to set their own threshold requirements, and supports multiple threshold settings to ensure that the threshold settings meet the customer's personalized needs.

[0133] Improve the early warning conditions of the equipment condition monitoring system.

[0134]

[0135]

[0136] The present invention provides an online monitoring and early warning method for the lifting mechanism of a casting crane under variable working conditions. This method enables the machine to replace point inspections in data checking, recording and judgment, etc. It uses multiple parameters such as the equipment status and working conditions of the lifting mechanism of the casting crane under variable working conditions, as well as the accumulated operation and maintenance experience, to determine the early warning rules and diagnostic models, so as to detect problems and eliminate faults as early as possible, and at the same time provide maintenance personnel with a basis for rapid fault location.

[0137] By installing vibration sensors on the reducer and drum bearing housing, and collecting data on motor current, temperature, and crane operating conditions, the transmission device of the lifting mechanism can be monitored online.

[0138] The signal transmission involved forms a wireless-wired-wireless data transmission structure, which eliminates the need for cable laying, prevents signal attenuation, and saves costs.

[0139] The working conditions determined by weight are more convenient and faster than those determined by current. By establishing the monitoring of the distance between the reducer and the drum, and comparing the changes in the distance between the drum and the reducer under different working conditions, the usage status of the drum coupling is monitored. The signal triggering conditions are extracted from the crane safety monitoring system, instead of using a high-speed shaft speed measuring device, which effectively avoids the interference of high temperature and dust conditions on the speed model, ensuring the reliability and safety of data extraction, and can also accurately determine the load status.

Claims

1. An online monitoring and early warning method for the lifting mechanism of a casting crane under variable working conditions, characterized in that: The aforementioned online monitoring is achieved by establishing separate monitoring systems for the operating status of the bearings and the operating status of the drum coupling. The monitoring of the drum coupling is achieved by establishing a monitoring system for the distance between the reducer and the drum. The monitoring of the distance between the reducer and the drum is achieved through the measurement and data uploading and processing by a distance measuring sensor installed on the reducer body. When the cumulative change in the measured axial distance is greater than 10mm, or When the difference between heavy-load and light-load conditions exceeds 5mm, an alarm for abnormality in the drum coupling is issued.

2. The online monitoring and early warning method for the lifting mechanism of a casting crane under variable working conditions according to claim 1, characterized in that: The monitoring of bearing operating conditions includes: monitoring bearing temperature, monitoring bearing speed, monitoring bearing acceleration, and monitoring bearing impact value.

3. The online monitoring and early warning method for the lifting mechanism of a casting crane under variable working conditions according to claim 1, characterized in that: The online monitoring is triggered by operating conditions and establishes a monitoring system based on the operating status of the bearings and the drum coupling under various operating conditions.

4. The online monitoring and early warning method for the lifting mechanism of a casting crane under variable working conditions according to claim 2, characterized in that: Multiple vibration measuring points are set on the motor, gearbox, and drum support bearing housing respectively. The monitoring of bearing temperature, bearing speed, bearing acceleration, and bearing impact value is achieved through the measurement and data upload and processing of temperature and vibration sensors set at each measuring point.

5. The online monitoring and early warning method for the lifting mechanism of a casting crane under variable working conditions according to claim 3, characterized in that: The aforementioned operating conditions are determined based on monitoring and judging the motor current or the lifting weight.

6. The online monitoring and early warning method for the lifting mechanism of a casting crane under variable working conditions according to claim 4, characterized in that: When the bearing temperature exceeds 60℃, a temperature abnormality alarm will be issued; When the effective value of the bearing speed is greater than 4.5 mm / s, a speed abnormality alarm will be issued; When the effective value of the bearing acceleration is greater than 2.5g, an acceleration abnormality alarm will be issued; When the bearing impact value or envelope value is greater than 3, an abnormal bearing impact value alarm will be issued.

7. The online monitoring and early warning method for the lifting mechanism of a casting crane under variable working conditions according to claim 5, characterized in that: When establishing trigger conditions based on operating conditions according to weight monitoring, the specific details are as follows: The PLC reads the weight and gear information and generates trigger signals for six working conditions: heavy load full speed up, heavy load full speed down, empty hook full speed up, empty hook full speed down, empty package full speed up, and empty package full speed down.

8. The online monitoring and early warning method for the lifting mechanism of a casting crane under variable working conditions according to claim 7, characterized in that: The working condition of heavy load and full speed ascent is determined by four limiting conditions: 100% speed, heavy load weight, lifting mechanism rising one gear, and lifting mechanism in four gears. The heavy-load, full-speed descent condition is determined by four limiting conditions: 100% rotation speed, heavy load weight, descent of the hoisting mechanism by one gear, and hoisting mechanism in four gears. The working condition of the empty hook rising at full speed is determined by four limiting conditions: 100% speed, no weight, the hoisting mechanism rising one gear, and the hoisting mechanism in four gears. The working condition of the empty hook descending at full speed is determined by four limiting conditions: 100% speed, no weight, the hoisting mechanism descending one gear, and the hoisting mechanism in four gears. The working condition of the empty package rising at full speed is determined by four limiting conditions: 100% rotation speed, empty package weight, lifting mechanism rising one gear, and lifting mechanism in four gears. The working condition of the empty package descending at full speed is determined by four limiting conditions: 100% rotation speed, empty package weight, the hoisting mechanism descending one gear, and the hoisting mechanism in four gears.

9. The online monitoring and early warning method for the lifting mechanism of a casting crane under variable working conditions according to claim 1, characterized in that: Online monitoring is based on the PLC settings for receiving, transmitting, and processing signals; All signals are transmitted wirelessly, while all signals are received via wired transmission.

10. The online monitoring and early warning method for the lifting mechanism of a casting crane under variable working conditions according to claim 1, characterized in that: The warning information is displayed through a user-friendly interface.

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