The vertical flange joint surface of the coupling parts has a tolerance level of six for the end face circular runout of the rotation center, and a tolerance level of seven for the other end faces circular runout. In most transmission systems of equipment, the driving and driven components are directly connected through gears, spline meshing, or other means. In high-speed equipment, such failures of couplings may lead to serious damage to the equipment.

The clutch can engage and disengage during operation, while the coupling cannot. It is a common phenomenon that the shaft diameters of the main and driven ends are different. When the torque and speed are the same, but the shaft diameters of the main and driven ends are not the same, the coupling model should be selected according to the larger shaft diameter. The movable performance can compensate or alleviate the additional load between the shaft, bearings, couplings, and other components caused by the relative displacement between rotating components.

Lubricating oil is sprayed into various small holes at the bottom of the gear teeth, and the oil is subjected to centrifugal force to enter the meshing surface for lubrication and cooling. After passing through the meshing surface, the oil flows out from both sides of the teeth. Lubricating oil is injected through the nozzle, and due to the centrifugal force acting on the lubricating oil during rotation, it maintains a certain lubricating oil layer on the outer circle of the gear. The lubrication method mainly plays a cooling role and is difficult to form an oil film. The wear of the tooth surface is faster than lubrication.

When using the above connection methods in the transmission system, when the driven part gets stuck due to a fault, the driven part and the driven part cannot be disconnected, resulting in damage to the driving part and the driven part. Couplings and clutches are mainly used to connect two shafts into one, for transmitting torque or motion. The requirements for the use of couplings and clutches are to be able to adjust the offset between the two shafts, absorb shocks and vibrations, and transmit a large torque.