1. Dry coupling, no need for lubrication
　　The elastic diaphragm coupling relies on the metal diaphragm to transmit torque and absorb the deformation caused by misalignment. There is no relative movement between the parts, no friction and wear, so it does not need lubrication, which is in line with the development direction of oil-free process equipment.The gear coupling is a rigid movable coupling. It relies on the relative slippage between the tooth surfaces to compensate for the misalignment of the two shafts. Therefore, the gear coupling must be lubricated, and the lubrication condition determines the gear coupling. The key to good shaft work.Especially in high-speed operation, it is more prominent, such as the separation and leakage of oil under the action of centrifugal force, as well as the selection of lubricating oil, often because the lubrication design uses the bearing lubricating oil of the connected machine, rather than the carrying capacity More suitable gear lubricants.Therefore, the lubrication problem of high-speed gear couplings is particularly prominent.On the other hand, the wear caused by the relative slippage of the tooth surface will cause a series of problems such as sludge and imbalance.Therefore, although gear couplings were once the best choice for high-speed and high-power applications, with the emergence and development of diaphragm couplings, gear couplings have gradually faded out.
　　2. All-metal structure, large torque transmission capacity and long service life
　　The diaphragm coupling uses a metal diaphragm as an elastic element, which has high strength and large load transfer capacity. There are no non-metal parts in the whole product, no aging problem, long service life, and it is suitable for harsh use environments.This is unmatched by non-metal elastic element couplings.
　　3. Great ability to compensate for misalignment and easy installation and alignment
　　The diaphragm coupling adopts a high-strength austenitic stainless steel diaphragm, which can withstand large deformations while transmitting torsion, thereby compensating for the misalignment of the two shafts.The non-metal elastic coupling is restricted by the low strength and easy aging of the non-metal elastic element, which not only has a short life, but also has a small compensation ability.Gear couplings are restricted by the relative slip speed of the tooth surface and lubrication conditions. According to the information, the relative slip speed of the tooth surface should not be greater than 0.12m/s. The angular compensation ability is small.Therefore, non-metal elastic couplings and gear couplings require higher installation and alignment.Once the misalignment exceeds the allowable range, it will cause rapid failure of the coupling.
　　4. Low axial and angular rigidity and little impact on equipment
　　The diaphragm coupling uses a thin metal diaphragm as an elastic element, which has low angular and axial stiffness, so the additional axial force and additional bending moment are small.Because the tooth surface of the gear coupling can slide relatively, people often think that the gear coupling can compensate for greater angular and axial misalignment without additional impact on the unit.In fact, this idea is wrong.After the elastic diaphragm coupling is loaded, due to friction and misalignment of the two shafts, a large additional axial force and additional bending moment will be generated on the shaft and the bearing.