A coupling is a device that is used to connect two mechanical objects together. One of the most common examples of a coupling used in daily life is a railway wagon. A flexible coupling is widely used in industrial applications because it allows for a certain degree of misalignment in usage. When motors are used to a great extent, there might be a certain degree of wear and tear and thus it may lead to misalignment. A flexible coupling will take care of that as it is of course, flexible.
Most machines that are driven by shafts require flexible couplings. Although these elements have to stay rigid while they are rotating and in motion, something needs to account for the various types of natural misalignment that can occur. Flexible couplings are ideal devices to compensate for these naturally occurring misalignments.
There are various types of misalignment which can take place such as lateral, angular and axial misalignment. Flexible couplings are designed to transmit torque equally between two moving parts to accommodate any misalignment. If you don’t compensate for any misalignment with the proper type of flexible coupling, your shafts and bearings may prematurely wear out and cause many problems.
Even though flexible couplings area little more complex, they are more commonly used than rigid couplings. Flexible couplings generally use inert and non-conductive elastomeric materials which provide them with flexibility. These materials are also used to electrically insulate one component from the other. There are three types of flexible couplings which are mechanical element, elastomeric element, and metallic element. Mechanical element couplings rely on the loose fit or rolling and/or sliding connections within the coupling that absorb any stresses and forces. The resilient material of elastomeric couplings such as rubber, nylon or another type of plastic, absorb the stresses. A mechanical element coupling consists of a thin metal diaphragm which flexes when it is stressed. Each group of couplings has its individual uses. For example, metallic couplings are best suited for use in high temperature and low inertia operations, whereas elastometric types are suited for lightweight applications.
There are certain prerequisites for choosing a flexible coupling. Primary concerns should be speed, torque and backlash. Flexible couplings are available in various types. Some of the common ones are: steel grid, coil spring, sliding block and metal contoured diaphragm. A flexible coupling must be properly lubricated and have good shock absorption capabilities.