The keyway fixation of elastic couplings is mainly suitable for high-torque transmission. To prevent axial sliding, elastic couplings are usually fixed and clamped with positioning screws and clamping screws. Generally, if the motor shaft is of type D, the positioning screw cannot be fixed. The holes of the coupling can be processed into D-shaped holes corresponding to the size of the motor shaft, and fixed with positioning screws without worrying about slippage. The expansion clamping fixation of elastic couplings is mainly achieved by tightening the four positioning screws on the end face of the coupling, which is suitable for some high-torque stepper motors and servo motors, such as expansion diaphragm couplings, expansion star couplings, expansion bellows couplings, and expansion sleeve elastic couplings, etc.

There is a pair of elastic rings between the hub and the shaft, and the inner and outer conical surfaces of the elastic rings are in contact. Under the axial force generated by tightening the nut, the inner ring shrinks and the outer ring expands, forming a connection between the hub, the elastic ring, and the shaft. This connection generates sufficient friction torque to transmit torque. The keyless coupling with elastic ring connection has good centering, is easy to install and disassemble, and has high load-bearing capacity. During assembly, the elastic ring can be pressed by the nut. When the shaft diameter is greater than 36mm or the end face of the hub, three or more screws can be used to press the elastic ring through a cover.

When the screws are tightened, the two-way conical elastic rings are pulled tight. The radial pressure generated by the inner and outer rings forms a friction torque between the hub, the elastic ring, and the shaft to transmit torque. For high-speed transmission shafts, couplings with high balance accuracy should be selected, such as diaphragm couplings, and eccentric slider couplings are not suitable. The main function of couplings is to connect two shafts, combine the two shafts to transmit motion and torque, and achieve the connection and separation between shafts, thereby realizing the transmission and interruption of power.

To reduce the vibration and peak load of the mechanical transmission system, couplings should also have certain buffering and vibration damping performance. However, due to fierce market competition, many manufacturers are constantly striving for profits, causing consumers to suffer losses from counterfeit and substandard products. Therefore, choosing high-quality products is also very important.