Disassembly and assembly method of plum coupling

Published: 2020-11-19

Couplings play an important role, and there are also many precautions. Let's take a look at the disassembly and assembly methods of plum couplings.

When disassembling the torx coupling, the connecting bolt is usually removed first.Because a layer of grease, corrosion products and other deposits are deposited on the surface of the thread, the bolt is not easy to disassemble, especially for the heavily corroded bolt, it is very difficult to disassemble.Suitable tools should be selected for the disassembly of connecting bolts, because the bearing surface of the bolt's outer hexagon or inner hexagon has been slipped and damaged, and the disassembly will be more difficult.For bolts that have been rusted or with a lot of grease stains, solvents (such as rust loosening agents) are often used to spray the joints of the bolts and nuts to allow the solvent to penetrate into the threads, which will be easy to disassemble.If the bolts cannot be removed, the heating method can be used, and the heating temperature is generally controlled below 200°C.By heating, the gap between the nut and the bolt is enlarged, and the rust is also easy to fall off, which makes it easier to disassemble the bolt.If none of the above methods work, only damage the bolts, cut or drill the bolts, and replace them with new bolts when assembling.The new bolts should be consistent with the original bolt specifications, and the bolts used for the new replacement of the high-speed equipment couplings should also be weighed so that the new bolts have the same weight as the connecting bolts on the same set of flanges.Due to the failure of the plum coupling itself, it needs to be disassembled. First, the entire coupling must be carefully inspected (especially for the damaged coupling), and the cause of the failure should be found out.

OnPlum couplingBefore disassembling, make some marks on the coordinated positions of the various parts of the coupling for reference when reassembling.For couplings used in high-speed machines, the connecting bolts are weighed, and the markings must be clear and not to be mistaken.

Cleaning, cleaning and quality assessment of all parts of the plum blossom coupling is an extremely important task after the coupling is disassembled.The evaluation of components refers to the comparison of the existing conditions of the size, shape and material properties of each component with the quality standards determined by the component design to determine which components can continue to be used and which components should be used. After repairing, which parts should be scrapped and updated.

In the process of disassembly of the plum coupling, the difficult task is to remove the hub from the shaft.For the hub of the coupling, a three-legged puller or a four-legged puller is generally used for disassembly.The selected puller should match the outer dimensions of the hub, and the right-angle hooks of each leg of the puller should be properly combined with the rear side of the hub, so that the imagination of slippage will not occur when exerting force.This method is only used for disassembly of hubs with relatively small interference. For hubs with relatively large interference, heating methods are often used or combined with hydraulic jacks for disassembly.

After the coupling bolt was broken and loosened, the pump unit was inspected on the axis, and it was found that the concentricity and parallelism of the axis were unqualified, and the coupling had a large deviation from the specified value.No looseness was found in the foundation bolts of the pump and the motor, and then the half coupling on the pump and the motor side was cranked to check its swing, and no abnormality was found.To this end, after removing all the bolts, replace with a new set of connecting bolts and re-tighten them. The bolts of the motor and pump remain stationary. After re-measurement of the axis, it is found that the parallelism and concentricity meet the requirements.

We pre-install the pump anchor bolts, hoist the motor to the motor platform, install the two halves of the coupling, adjust the spacing, and then use a steel ruler or knife edge ruler to roughly align the two halves of the coupling.Make holes on the motor base, place the anchor bolts, tighten the motor anchor bolts, and retest the concentricity and parallelism.Different from traditional drum-tooth couplings, the two shafts should be centered before the diaphragm coupling is installed, and then the diaphragm should be inserted and the bolts should be tightened, because the diaphragm coupling is a type of coupling that coexists with rigidity and flexibility. , The connecting bolts of the semi-coupling will have a pulling effect on the two shafts. If the bolts are tightened in advance and then the alignment data are measured, there may be a big deviation from the actual value.

After the coupling connecting bolts are loose or broken, the pulling force of the bolts no longer exists, and the axis returns to an unstressed state. At this time, the measured concentricity and parallelism deviations are quite different from the manufacturer's requirements.If you want to adjust the axis to a qualified state before pre-tightening the connecting bolts, pull out the motor anchor bolts. That is to say, the motor anchor bolt holes and the motor base holes are misaligned, and the anchor bolt holes of the motor base need to be adjusted. Only by reaming can the anchor bolts be re-placed, first connect the diaphragm and tighten the bolts before adjusting the axis.If a material with better plasticity is subjected to greater stress, there will be an obvious stage of yielding and plastic deformation.

In normal operation, the tube mill requires that the transmission connection pipe and the output shaft of the reducer be in the same straight line, and the transmission connection pipe flange end surface is in the vertical plane, which is the ideal position.Adjust the relative position between them during installation to get the state of operation as much as possible.The connecting bolt of the coupling usually has good plasticity, and the fracture of the broken bolt is relatively flat, without obvious plastic deformation, showing the characteristics of brittle fracture.Fatigue fracture caused by periodic stress caused by the misaligned axis system of the coupling.