Main influence factors and improvement measures of diaphragm coupling

　　(1) Misalignment of installation.The misalignment of the bearings on both sides of the coupling and the two ends of the system has a great influence on the static characteristics of the system support. Misalignment makes the vibration isolation effect of the diaphragm coupling worse, and the misalignment deteriorates the stability of the system. Trend, which in turn affects the service life of the diaphragm coupling.Therefore, it is necessary to align the diaphragm coupling before installing. There are three common alignment methods: the single meter method is suitable for the relative position of each axis in a cold state, and the distance between the two halves of the coupling is long, Alignment of units with a small coupling diameter; the double-meter method is suitable for the alignment of the mechanical equipment when the shafts of the mechanical equipment are in a horizontal state. At this time, it is more convenient to use the double-meter method to align, but pay attention to the alignment process. Make the shaft close to one end in order to eliminate the influence of axial movement on the alignment reading. In the installation of general-purpose pumps, fans and other equipment, we often use the double-meter method for alignment; XNUMX. The table method alignment is suitable for the alignment of multi-stage units and the cold state of each shaft is in a horizontal position. The use of the three-meter method can eliminate the influence of the relative movement of the two axial directions and obtain higher alignment accuracy.This method is used in the alignment of reciprocating compressor units and large centrifugal units with low rotation belts.
　　(2) The diaphragm is damaged.The diaphragm is the key element of the diaphragm flexible coupling. Due to the offset between the axes, the transmission of torque, and the bearing of centrifugal force, the diaphragm is in a complex state of stress during operation.Its fatigue life determines the normal service life of the diaphragm coupling.Tensile fracture at the ends of the connecting holes at both ends and the instability bending deformation of the diaphragm under pressure are common manifestations of diaphragm damage, so the probability of its failure has a great influence on the overall failure probability of the diaphragm coupling, so in engineering practice We must check and repair the diaphragm regularly to ensure its stable transmission performance.The waist-shaped diaphragm has a reasonable shape and low stress level. Under the same parameters, the calculated life is much longer than that of the annular diaphragm, and the additional load caused on the coupling is small, so the waist-shaped diaphragm can be used. Piece coupling.The rationally designed diaphragm structure and the number of laminated layers make the diaphragm coupling have a longer service life and meet the requirement of no damage during the overhaul of the unit.
　　(3) Bolt damage and deflection.The undercut at the bolt root causes stress concentration due to poor machining quality, and there are inclusions in the material, and there is also a problem with the installation of the laminated diaphragm coupling and other parts of the unit (such as fan blades and gearbox) are also damaged, etc. Due to the existence of various factors, the laminated diaphragm coupling bolt set is used in the working condition of frequent start and large load. Once the working stress exceeds the working stress that the bolt can withstand, it will cause fatigue and fracture, which will eventually lead to the laminated diaphragm. The coupling is damaged.Improvement measures include: ①When designing laminated diaphragm couplings, sufficient attention should be paid to the processing quality of bolt undercut grooves, and the metallurgical quality and heat treatment process of bolt materials should be strictly controlled to improve the fatigue strength of bolts; ②Laminated membrane The installation of the piece coupling must strictly control the installation accuracy, reduce the angular deviation, radial deviation and axial compression or tension between the two halves of the coupling, strictly control the dynamic balance accuracy of the coupling, and reduce vibration In order to reduce the alternating cyclic stress of the bolt group, the pre-tightening force of the installation bolt must be controlled within the specified range; ③In the coupling work site, a vibration monitoring device must be installed to give an alarm in time for abnormalities to avoid short-term overload , To prevent the harm from further expanding.