With the rapid development of science and technology, advanced technology has been widely applied in coal mine equipment. In coal mine hoists, the use of sliding bearings has greatly improved the performance of the hoist, and the accuracy has also been improved. Therefore, the use of sliding bearings in coal mine hoists is more widespread. In the process of using the sliding bearings of the hoist, due to some factors of its own configuration, the maintenance and repair costs of the sliding bearings of the hoist are relatively high, especially the wear problem of the sliding bearings. The article analyzes the reasons for the wear of sliding bearings in coal mine hoists and proposes measures to strengthen the maintenance and adjustment of sliding bearings in hoists, aiming to provide theoretical reference for improving the overall efficiency of hoists.
1. Reasons for Wear of Sliding Bearings in Coal Mine Elevators
(1) Bearing defects
Some defects in the bearing itself are one of the reasons for the wear of sliding bearings, among which bearing defects include three aspects: first, poor quality of tin hanging, which causes some problems in the bonding between the back layer and lining layer of the bearing shell; Secondly, during the process of pouring the bearing shell, due to temperature reasons (insufficient heat), gas accumulates in the hanging shell; Thirdly, there are large particles in the tin antimony alloy, which cause uneven distribution of particles inside the Babbitt alloy, all of which are defects of the bearing itself.
(2) Assembly is not standardized
The assembly of sliding bearings was not carried out according to standard requirements, which also resulted in wear problems in the later stage, manifested in the following three aspects: firstly, the centerline of the bearing does not coincide with the centerline of the base; Secondly, the bearing does not match the base, which can cause dangerous problems such as sliding; Thirdly, uneven clearance between bearings and excessive bearing standards are all manifestations of bearings not meeting assembly standards.
(3) Improper use of bearings
One important reason for the wear of sliding bearings is improper use of the bearings, which manifests in the following three aspects: firstly, the entry of foreign particles into the bearings; Secondly, improper use of lubricant additives can corrode bearings; Thirdly, insufficient lubrication viscosity leads to bearing wear.
2. Strengthen the maintenance of sliding bearings in elevators
(1) Maintenance process of sliding bearings for elevators
In the process of using the sliding bearing hoist, several maintenance processes have been proposed based on the usage situation, namely, maintenance of various components of the sliding bearing: when the power is cut off, measure the gap between the motor rotor and stator to ensure that it is within a reasonable range; Secondly, inspect and remove the coupling housing, measure the gap between the end faces, and ensure that it is within the standard range; Thirdly, inspect and remove all components of the motor, measure the bearing clearance and shaft level to ensure they are within the standard range; Fourthly, check the wear condition of the shaft circumferential surface at the bearing and carry out corresponding treatment according to the specific situation to make it meet the standards; Fifth, detect the wear of the bearing shell and make corresponding adjustments, clean the bearing base to ensure its cleanliness; Sixth, check the installation between the bearing pad and the motor rotor to see if the installation is completed according to the standard. After installation, measure the levelness of the shaft to ensure it meets the standard range.
After maintenance, the above components are uniformly installed into the elevator system according to standards, and then undergo corresponding debugging to ensure the normal operation of the elevator sliding bearings.
(2) Maintenance of sliding bearings in operation
2.1 Temperature detection
When repairing sliding bearings in operation, the first thing to consider is whether the temperature meets the standard. If the temperature is too high or too low, it will affect the gap between the bearings and cause bearing failure. Therefore, it is necessary to perform temperature detection on the running bearings. Specifically, by measuring the temperature through the bearing's temperature measuring hole and using a thermal resistor for detection, once the temperature is found to be too high or too low, it will be reflected to the summary port through the PC interface to remind the temperature situation and take effective measures to avoid bearing failure caused by temperature.
2.2 Vibration detection during operation
Excessive amplitude of bearings during operation can also cause bearing failures, thereby affecting the performance of the hoist. So, corresponding techniques should be used to detect the amplitude during operation. This time, displacement based sensor detection technology is used to repair and improve amplitude faults based on the detection results, avoiding bearing faults caused by excessive amplitude.
2.3 Regular ferrographic analysis
Iron spectrum analysis is a detection of lubrication level and bearing friction. If the lubricating oil does not meet the standards, the friction debris generated by bearing friction will have a certain impact on the bearing. So through ferrography analysis and detection, the occurrence of bearing failures can be effectively avoided.
3. Determination of clearance of sliding bearings and other adjustments
There are two main types of clearances for sliding bearings, namely radial clearance and axial clearance. These two clearances are important conditions for ensuring the normal and continuous operation of the hoist. The former ensures accurate operation between the shaft neck and the bearing, while the latter ensures that the length of the shaft neck temperature rise can be freely extended and retracted. The following are instructions for determining the bearing clearance and other adjustments: determining the clearance and determining the radial clearance of the sliding bearing, usually based on the nature of the design and assembly. For determining the axial clearance of sliding bearings, it is necessary to consider their specific structural form and ensure that it is greater than the Z-length expansion and contraction during the operation of the journal. Usually, the structural form needs to be determined based on the different structures; Secondly, the measurement and adjustment of the clearance between sliding bearings must first arrange the shaft neck? After determining the end position, the clearance of the sliding bearing can be determined. Relevant measurement operations can be carried out by using dial gauges, feeler gauges, etc., and then the data from these two extreme positions can be superimposed for calculation to obtain the axial clearance size; Thirdly, adjust the clearance. If the clearance between the top of the sliding bearing is greater than the limit value, the adjustment force of the tile mouth should be weakened to ensure that the force is appropriate.
4. Conclusion
In summary, the rational and scientific use of coal mine hoists is of great help in improving the productivity of coal mines, and the degree of wear of sliding bearings, which are important components of hoists, directly affects the production efficiency of coal mines. Therefore, analyzing and studying the wear of sliding bearings in the hoist ensures the normal operation of the hoist, reduces the frequency of equipment maintenance, lowers costs, thereby improving the economic benefits of coal mining enterprises and promoting the development of the coal mining industry.
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