The search of the coupling is one of the important tasks of the machine installation. The purpose of the alignment is to make the two axes of the driving shaft and the driven shaft in the same straight line when the machine is working. The accuracy of the alignment is related to whether the machine can operate normally. , Especially important for high-speed machines.

　　Accurate alignment of two shafts is difficult to achieve, and it is more difficult to always maintain accurate alignment for continuously operating machines. The uneven thermal expansion of various parts, the deflection of the shaft, the uneven wear of the bearing, the displacement generated by the machine, and the Uneven sinking of the foundation, etc., are all causes that make it difficult to maintain shaft alignment. Therefore, when designing the machine, it is specified that the two shafts have an allowable deviation value, which is also required when installing the coupling. From the perspective of assembly, As long as the coupling can reliably transmit torque, the greater the allowable deviation of the two shafts, the easier it is to meet the requirements during installation.However, from the perspective of installation quality, the smaller the deviation of the two axes, the greater the alignment, the better the machine's operation and the longer the service life.

　　The cost of couplings with general accuracy requirements of drum gear couplings is lower than that of high-precision couplings; the cost of couplings with simple structure and good manufacturability is lower than that of couplings with complex structure and poor manufacturability; general The cost of couplings using materials as raw materials is lower than that of couplings using special materials as raw materials; the cost of flexible couplings with non-metallic elastic elements is lower than that of flexible couplings with metal elastic elements.When choosing a coupling, price is an important factor that cannot be ignored, and sometimes it is even a decisive factor.For general working conditions, there is no need to choose more expensive high-precision couplings. For economic reasons, users often cannot choose some flexible couplings with good performance but higher prices.When selecting a coupling, it is necessary to consider the above-mentioned various factors in accordance with the actual conditions and requirements of the selection, and select the type, type and specification of the coupling that suits your needs from the existing standard couplings.Under normal circumstances, the existing standard coupling can basically meet the needs of different working conditions.