Analysis Of Easy Failures Of Roller Conveyor
Sep 21, 2020
Roller conveyors are very suitable for conveying all kinds of boxes, bags, pallets, etc., with simple appearance structure, high reliability, and convenient use and maintenance. When conveying materials, it is very suitable for the conveying of goods on the bottom plane. It is mainly composed of a driving roller, a frame, a bracket and a driving part. It has a large conveying capacity, fast speed, and light operation, which can realize multiple varieties. The characteristics of collinear shunt conveying.
Due to the impression that the roller conveyor is affected by factors such as poor operating environment and heavy conveying load, some faults will often occur during operation, mainly including belt deviation, roller breakage, and material spilling. Among them, the roller shaft failure is the roller conveyor The most common hidden trouble in machine operation. If the operator does not take the necessary treatment measures in time, not only will it bring certain safety hazards to the daily operation of the port terminal, but also the broken shaft of the drum may cause a vicious accident and cause significant economic losses. Therefore, how to effectively solve the failure of the drum shaft is one of the difficult problems to be solved by port operators.
1. The structure of the drum
Many port reversing drum design drawings adopt cast-welded structure, that is, the connecting plate is ZG25～35 integral cast steel, the drum skin is rolled by Q345 steel plate, and the shaft is 40Cr.
2. Force analysis of the drum
The force of the drive roller is: the pressure f0 produced by the tension of the belt conveyor, the friction force Ff and the main power moment Mp. The force of the reversing roller is: belt tension f0 and friction force Ff. Compared with the two rollers, the driving roller has one more active torque than the reversing roller. However, due to the different tensioning forms of the reversing roller, the belt tension it bears is sometimes greater. Practice has proved that the fracture probability of the redirecting roller is higher than that of the driving roller.
Practice has shown that, although the maximum working stress of a roller that has been working under alternating stress for a long time is much lower than the ultimate stress of the material under static load, it will suddenly fracture accident, and it will be brittle without obvious plastic deformation. Fracture, that is, fatigue failure. The process of fatigue failure is not at the maximum stress of the roller, but at the defect of the material. The fracture of the shaft is at the sudden change and stress concentration near the bearing platform, and the tube skin is at the weld. In the welding process, due to the high temperature, there are small holes in the welding joints, which form innate stress concentration points. After repeated stress changes, micro cracks, which are fatigue elements, are first produced. This kind of crack gradually expands with the increase of the number of stress cycles, and the materials at both ends of the crack are time-divisionally combined and ground each other to form a smooth section of the section. As the cracks continue to expand, the effective area of the weld joint continues to decrease, so that it suddenly breaks, causing serious consequences.
