The diaphragm coupling bolt connection does not need to be threaded on the connecting piece, the use is not restricted by the connecting piece, the structure is simple, and the disassembly and assembly are convenient. Stud bolts can be used in occasions where bolts cannot be used due to structural restrictions, but a compact connection structure is required. The bolt connection does not have a nut and has a smooth exposed surface, but it is not suitable for frequent disassembly and connection, so as not to damage the threaded hole.
During the service life of the diaphragm coupling, it is necessary to maintain the wedge-shaped clearance surfaces that are inclined to each other, add lubricating oil, and enter the small opening from the large port. The two surfaces have sufficient relative movement speed, the fluid has sufficient viscosity, and the oil supply is sufficient. In the maintenance process, it is important to grasp the basic scope of hydrodynamic lubrication, which is also the theoretical basis of sliding bearing design.
The diaphragm coupling can actively compensate for the axial, radial and angular offset caused by the motor, as well as the influence caused by factors such as manufacturing errors, installation errors, bearing deformation and temperature rise. Diaphragm coupling is a metal elastic element in flexible coupling. The advantages of driven torque transmission, elastic vibration, no noise, and no lubrication are the ideal products to replace gear couplings and general couplings.
The plum blossom elastic coupling transmits torque mainly through the engagement of the convex teeth of the two halves of the coupling and the plum blossom elastic body. There is no gap between the protruding teeth and the elastic body. When the axes of the two rotors are relatively offset, the elastic element deforms accordingly, which plays a role of automatic compensation.
As the coupling is rotating, the relative offset direction and offset 5 will periodically change for each elastic body, which is not convenient for mechanical analysis. The author took the relative offset along the elastic body and the rotation line. Along the direction of the elastomer.

Plum-shaped elastic couplings are widely used in metallurgy, petroleum, chemical industry, etc. due to their small radial size and moment of inertia, no gap, good vibration reduction and buffering effects, and strong axial, radial and angular compensation capabilities. Lifting and other industries, especially medium and high speed working conditions with frequent starting and forward and reverse rotation. Although the plum blossom flexible coupling has good misalignment compensation capabilities, the misalignment of the coupling still produces additional force and torque on the rotor and bearing system, and these additional forces often bring serious consequences.
With the advancement of science and technology, the rotor system is gradually developing in the direction of high speed and heavy load. People have realized the seriousness of the coupling misalignment problem. Many scholars have carried out related theories and experiments, but mainly concentrated on the drum tooth type. For couplings and diaphragm couplings, the misalignment of plum blossom flexible couplings is rarely seen in various documents.
There are 3 types of coupling misalignment: parallel misalignment, angular misalignment and comprehensive misalignment. This article will explore theoretically the parallel misalignment of plum blossom flexible couplings.