Correct use of elastic diaphragm coupling

Published: 2020-10-15

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.Gear couplingIt is a rigid movable coupling. It relies on the relative slip between the tooth surfaces to compensate for the misalignment of the two shafts. Therefore, the gear coupling should be lubricated, and the lubrication conditions determine the performance of the gear coupling. The essential.Especially in high-speed operation, it is prominent, such as under the action of centrifugal force, oil separation, leakage, etc., as well as the choice of lubricating oil, often because the lubrication design uses the bearing lubricating oil of the connected machine instead of the appropriate load capacity 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 choice for high-speed and high-power applications, with the emergence and development of diaphragm couplings, gear couplings have gradually faded out.

The structure of the elastic pin coupling is relatively simple, similar to the flange coupling, it is easy to manufacture, does not require lubrication, and does not need to be bonded with metal vulcanization, but the coupling bolt is replaced by a pin with an elastic sleeve.Because oil-resistant rubber is commonly used through pupa shape to improve its elasticity.It is convenient to replace the elastic sleeve, without moving the half coupling, and has a certain degree of compensation for the relative offset of the two shafts and the performance of damping and buffering.

The work of the elastic sleeve is compressed and deformed. Because the thickness of the elastic sleeve is thin, the volume is small, and the elastic deformation is limited, the elastic sleeve pin coupling can compensate the axis displacement and elasticity, but the allowable compensation amount for the axis displacement is less. The elasticity is weak.The elastic sleeve pin coupling relies on the locking force of the pin group to generate the friction torque on the contact surface, and compress the rubber elastic sleeve to transmit the torque.It is suitable for small and medium-power shafting transmissions with good rigidity of the installation base, high centering accuracy, low impact load, and low vibration reduction requirements. 

In the flange coupling, the bolt connection is a rigid connection, and the assembly requirements are high.The elastic sleeve in the elastic sleeve pin coupling is an elastic connection, which can make up for the limited defects in assembly, protect the main parts, and facilitate maintenance and replacement.

The elastic pin coupling is a pin made of several non-metallic elastic materials, which is placed in the flange hole of the two halves of the coupling, and the two halves of the coupling are connected by the pin. The coupling has a simple and easy structure. It is more convenient to manufacture, assemble, disassemble and replace the elastic element, without moving the two couplings.

Diaphragm couplingThe use of high-strength austenitic stainless steel diaphragm 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 the coupling to fail.

The diaphragm coupling uses a thin metal diaphragm as an elastic element, which has low angular and axial rigidity, 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 large 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.