4.Relative Misalignment of Two Shafts Connected by the Coupling
The two shafts connected by the coupling are deformed due to manufacturing errors, assembly errors,mounting errors, shaft deformation, pedestal deformation, bearing wear, temperature changes (thermal expansion and contraction), relative movement between components, etc. factors that produce relative misalignment.
5.Coupling Transmission Accuracy
The small torque and the shafting drive based on the drive motion require the coupling to have a high drive tip, and the metal flexible coupling should be selected.Large torque and drive-based shafting drive also need high drive tip. If high-speed，non-metallic components flexible couplings or flexible couplings with space between movable components should be avoid, and disk-coupling should be selected.
6. Coupling Size, Installation and Maintenance
The overall dimensions of the coupling, ie the maximum radial and axial dimensions, must be within the allowable installation space of the machine. The coupling selected should be easy to install and disassemble, require no or easy maintenance, allow replacement of wear-prone parts without moving the two shafts, and easy centering.
7.Working Environment
Couplings are used in a variety of different products. The surrounding working environment is complex, like temperature, limit, water vapor, dust, sand, radiation,etc. are the important factors that must be considered when selecting a coupling.
8.Economy
Due to the different structure, material, size and precision of the couplings of various types and specifications, the cost and price are very different. The coupling cost required for the tip is cheaper than coupling with high precision.The coupling with simple structure and good craft-ability is cheaper than the coupling with complicated structure and poor craft-ability. The coupling made of a general material is cheaper than that made of a special material.
