Ever-Power Co., Ltd.
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Coupling compensation type of diaphragm
As the key elastic element of the diaphragm coupling, the diaphragm bears the main load during operation.
The forms of misalignment that the diaphragm coupling can compensate include the following three basic types: angular (the center lines of the two shafts intersect at the midpoint between the ends of the two shafts at an angle), transverse (the center lines of the two shafts are offset in parallel) and Axial (the axial gap between the two shafts is too large).The actual offset that occurs during the operation of the rotating shaft system is often a combination of any of the above two types of misalignment or three types of misalignment at the same time, so the load and deformation of the diaphragm coupling during actual work are more complicated.
When the diaphragm coupling rotates, its angular deviation will produce alternating stress, which alternates once per rotation.The dynamic stress of the diaphragm will cause the fatigue damage of the diaphragm and the bolt, so the accurate calculation of the dynamic and static composite stress is the key to predicting the life of the diaphragm coupling and the reliable operation of the diaphragm coupling.
The existing related research is mostly limited to the analysis of the stress distribution of the diaphragm when it is subjected to a certain load alone, while the dynamic and static composite stress when the diaphragm is actually subjected to a complex load is rarely involved.
The membrane segment between two adjacent bolt holes can be equivalent to a cantilever beam, and the method of material mechanics is used to deduce that the connecting rod diaphragm coupling can bear torque, centrifugal load, axial offset, and angular deviation independently. The calculation formula for the internal stress of the diaphragm is shifted, and a method for calculating the torsional stiffness of the diaphragm is proposed. It is a typical method to analyze the stress and stiffness of the diaphragm by using empirical formulas, but its big disadvantage is that the area around the bolt hole cannot be considered. The influence of the stress concentration effect causes a large gap between the calculated stress and the actual stress.
XNUMX. Great ability to compensate misalignment, easy to install and align
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 the coupling to lose quickly.
XNUMX. The axial and angular stiffness is low, and the impact on the equipment is small
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.
XNUMX. Dry coupling, without 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 slip between the tooth surfaces to compensate for the misalignment of the two shafts. Therefore, the gear coupling should be lubricated, and the lubrication condition determines the gear coupling The key to good or bad work.Especially when it is running at high speed, it appears to be 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, rather than the 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.
XNUMX. 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.
The forms of misalignment that the diaphragm coupling can compensate include the following three basic types: angular (the center lines of the two shafts intersect at the midpoint between the ends of the two shafts at an angle), transverse (the center lines of the two shafts are offset in parallel) and Axial (the axial gap between the two shafts is too large).The actual offset that occurs during the operation of the rotating shaft system is often a combination of any of the above two types of misalignment or three types of misalignment at the same time, so the load and deformation of the diaphragm coupling during actual work are more complicated.
When the diaphragm coupling rotates, its angular deviation will produce alternating stress, which alternates once per rotation.The dynamic stress of the diaphragm will cause the fatigue damage of the diaphragm and the bolt, so the accurate calculation of the dynamic and static composite stress is the key to predicting the life of the diaphragm coupling and the reliable operation of the diaphragm coupling.
The existing related research is mostly limited to the analysis of the stress distribution of the diaphragm when it is subjected to a certain load alone, while the dynamic and static composite stress when the diaphragm is actually subjected to a complex load is rarely involved.
The membrane segment between two adjacent bolt holes can be equivalent to a cantilever beam, and the method of material mechanics is used to deduce that the connecting rod diaphragm coupling can bear torque, centrifugal load, axial offset, and angular deviation independently. The calculation formula for the internal stress of the diaphragm is shifted, and a method for calculating the torsional stiffness of the diaphragm is proposed. It is a typical method to analyze the stress and stiffness of the diaphragm by using empirical formulas, but its big disadvantage is that the area around the bolt hole cannot be considered. The influence of the stress concentration effect causes a large gap between the calculated stress and the actual stress.
XNUMX. Great ability to compensate misalignment, easy to install and align
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 the coupling to lose quickly.
XNUMX. The axial and angular stiffness is low, and the impact on the equipment is small
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.
XNUMX. Dry coupling, without 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 slip between the tooth surfaces to compensate for the misalignment of the two shafts. Therefore, the gear coupling should be lubricated, and the lubrication condition determines the gear coupling The key to good or bad work.Especially when it is running at high speed, it appears to be 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, rather than the 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.
XNUMX. 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.
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