The selection of a coupling diaphragm primarily considers the required rotational speed of the shaft, the magnitude of the load, the installation accuracy of the two connected components, the smoothness of rotation, and price. Referring to the characteristics of various coupling diaphragms, a suitable type of coupling diaphragm is chosen. The working rotational speed and the resulting centrifugal force of the coupling diaphragm. For high-speed transmission shafts, a coupling diaphragm with high balancing accuracy, such as a membrane-type coupling diaphragm, should be used, rather than an eccentric slider coupling diaphragm, etc. The size and nature of the torque to be transmitted and the requirements for vibration buffering functionality.
The main function of the coupling diaphragm is to connect two shafts (and sometimes shafts with other rotating parts), enabling them to rotate together to transfer motion and torque, thereby achieving connection and disconnection between shafts, facilitating the transmission and interruption of power. The coupling diaphragm also has the ability to compensate for shaft misalignment, reducing additional loads caused by relative misalignment between the connected shafts, enhancing transmission performance, and extending the lifespan of the machinery. To minimize vibrations in the mechanical transmission system and reduce peak impact loads, the coupling diaphragm should also possess buffering and shock-absorbing properties. However, due to intense market competition, many manufacturers seek to make excessive profits by passing off substandard products as high-quality ones, resulting in consumer losses. Therefore, the importance of selecting the right products cannot be overstated.
Disassembly and assembly are opposite processes with different purposes. The assembly process involves assembling the coupling diaphragm according to the assembly requirements to ensure reliable torque transmission. Disassembly is generally due to equipment failure or the need for maintenance of the coupling itself, where the coupling diaphragm is disassembled into components. The extent of disassembly is typically determined by the maintenance requirements, ranging from simply separating the connected shafts to fully disassembling the coupling and removing the hubs from the shafts. There are many types of coupling diaphragms with varying structures, and the disassembly process varies accordingly. This article mainly discusses some of the issues that need to be addressed during the disassembly of coupling diaphragms.
Due to the tight connection between the coupling diaphragm gear and the vibration shaft (an interference fit), and the limited space within the flange, it is quite challenging to disassemble the coupling diaphragm gear. To address this, we have designed a disassembly tool that is both simple, convenient, and practical. When disassembling the coupling diaphragm due to a fault, a thorough and detailed inspection of the entire diaphragm (especially for those already damaged) is necessary to determine the cause of the fault.
Before disassembling the coupling diaphragms, some markings should be made on the positions where the diaphragms fit together for reference during reassembly. For coupling diaphragms used in high-speed machines, the connecting bolts have been weighed and clearly marked; they must not be confused.
When removing the coupling diaphragm, it is generally advisable to first remove the connecting bolts. Due to the accumulation of oil, corrosion products, and other debris on the threaded surface, bolts can be difficult to remove, especially for those severely rusted. When removing connecting bolts, choose the right tools, as the force surfaces of the external or internal hexagonal heads may have slipped and damaged, making removal challenging. For bolts that are rusty or have excessive oil, it is often effective to spray a solvent (such as a rust penetrant) on the bolt and nut connection, allowing it to seep into the threads, which makes removal easier.
During the coupling diaphragm disassembly process, the challenging task is removing the hub from the shaft. For hubs with key connections, it is typically done using a three-leg or four-leg wrecker. The wrecker selected should match the hub's外形 dimensions, ensuring that the right-angle hooks of the wrecker's legs fit snugly against the rear side of the hub without the risk of slipping when force is applied. This method is only suitable for hubs with minimal interference fit; for hubs with a larger interference fit, heating methods or the use of a hydraulic jack in conjunction are often employed.
Thoroughly cleaning, decontaminating, and conducting quality assessments on all components of the coupling diaphragm is a critical task following the disassembly of the diaphragm. Component evaluation involves comparing the current condition of each component's dimensions, shape, and material properties after operation to the quality standards determined by the component design, determining which components are suitable for continued use, which should be replaced, and which ones should be scrapped and replaced with new parts.
