Axial Offset of Diaphragm Coupling and Its Application Analysis

Stress analysis of diaphragm
　　The diaphragm group is the main elastic element of the diaphragm coupling.During operation, the diaphragm assembly is subjected to composite forces such as stretching, squeezing, and shearing, and is in a complex state of force, and thus transmits torque and motion, while absorbing vibration and compensating for deviation.
　　Since the stiffness of other parts in the coupling is much larger than that of the diaphragm, and the force of the diaphragm is complicated, only the stress analysis of the diaphragm is studied here.In order to simplify the calculation, the surface shear force generated by the small relative movement between the diaphragms is not considered, that is, all the diaphragms are regarded as a whole.The load borne by the diaphragm is as follows:
　　Diaphragm couplings are usually installed on high-speed transmission shafts. The centrifugal inertia force of high-speed machinery is very important in structural stress calculations.The direction of the centrifugal inertia force generated by the mass of bolts, washers, etc. and the centrifugal inertia force generated by the mass of the diaphragm group itself are both radially outward, so that the diaphragm group is subjected to centrifugal tensile stress.The centrifugal stress that the diaphragm bears varies greatly with the speed, but it can also be regarded as a constant stress under operating conditions.
Although the torque transmitted by the diaphragm assembly is very large when the diaphragm coupling is working, practice has proved that the main failure of the diaphragm coupling is not caused by the insufficient torque transmission capacity of the diaphragm assembly, but the alternating change of the diaphragm. Caused by cyclic compound stress.This composite stress is mostly caused by the additional load caused by the misalignment of the two shafts connected by the diaphragm coupling.
　　The axial offset KA of the diaphragm coupling is affected by the specifications of the coupling and the number of bolts. The larger the specifications of the coupling, the greater the axial offset that it can withstand.Axial deviation will cause great stress on the diaphragm. Therefore, in order to ensure a long service life of the coupling, it is required that the diaphragms are as close as possible during installation and the diaphragms are as flat as possible.At the same time, the axial deviation of the equipment due to thermal expansion and contraction is taken into account.For the double diaphragm coupling, after the axial deviation of the coupling is averaged by the diaphragm groups on both sides of the intermediate body, the axial deviation of the diaphragm group is half of the axial deviation of the diaphragm coupling.