Effective anti-loose measures for threaded joints of coal mining machinery shearers Yao Yu (Jingxi Mining Group Electromechanical General Plant, Jixi 158130, Heilongjiang) proposed several effective anti-loose methods for fasteners subjected to large alternating loads and vibrations. The hydraulic nut locking method with large pre-tightening force, convenient fastening, labor saving and anti-loose effect is introduced in detail.
3: A 0 Foreword The shearer should cut the bottom, top and rock layers during operation, and bear large alternating loads and vibrations. The fasteners often loosen and cause failure of the transmission and components. Oil leakage failure. It can be seen that the effective anti-loose of the threaded joint of the shearer is a very important issue. This paper introduces several effective anti-loose methods for the shearer.
1Reliable anti-loose method of several threaded joints of coal mining machine plus elastic elongation of connecting bolts In the design of connecting bolts of domestic coal mining machine, the bolts are often smaller in diameter and smaller in length, and the elastic elongation of bolts is small. The loose effect is poor. Before the bolt yields, the tensile deformation of the bolt is elastic deformation, the effective length of the bolt; the elastic modulus of the bolt material; the cross-sectional area of ​​the bolt.
It can be seen that the elastic elongation after bolt loading is proportional to the pre-tightening force and the bolt length, and inversely proportional to the cross-sectional area of ​​the bolt. The greater the elastic elongation of the bolt, the better the anti-loose effect. The new type of coal mining machine in foreign countries adopts the method of high strength, fine diameter and lengthening bolt length, and the anti-loose effect is better. For example, most of the bolts between the UK AM500 coal mining enclosures use M30 thinner diameter high-strength bolts.
It can be known from the formula (1) that the bolt elongation is proportional to the effective length of the bolt and inversely proportional to the cross-sectional area of ​​the bolt. The connection between the coal mining bodies is often limited due to the limited thickness of the two sides. The length of the connecting bolts cannot be considered in the process of programming. The system safety is fully considered, and the design with interlocking function is adopted, and the programs with different control methods are used. Write separately, so that the program structure is clear and easy to program.
3 Conclusion The actual use results show that the use of PLC control system greatly improves the reliability of the system, reduces the failure rate, and improves the automation level of the equipment.
The system can be widely used for cargo transportation between floors of hotels, warehouses, etc., and has the advantages of saving manpower and convenient operation.
Touch, display, various sensors and warning devices can be added to the system to further improve reliability and safety.
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