Shaft coupling is a transmission device that connects two different shafts and absorbs the installation error between the shafts to reduce wear, impact, vibration, noise and other effects. Mainly divided into two categories, elastic couplings and rigid couplings, they are used in different occasions, such as motors, pumps, engines and other machinery and equipment. A good coupling can have excellent durability, corrosion resistance, and can withstand high torque and high speed.