Coupling catalogs will show the maximum angular misalignment tolerable in each coupling. Before we enter into a discussion about all of the evaluation factors to consider in selecting the right coupling type, let’s review some basic terminology that will be used in this handbook.ĪNGULAR MISALIGNMENT: A measure of the angle between the centerlines of driving and driven shafts, where those centerlines would intersect approximately halfway between the shaft ends. This handbook will be a guide to assessing the features and limitations of the many standard types of couplings on the market. Each design has strengths and weaknesses that must be taken into consideration because they can dramatically impact how well the coupling performs in the application. There is a trade-off associated with each, not the least of which can be purchase costs. There is not one coupling type that can “do it all”. Another is to dampen torsional (rotational) vibration that occurs naturally in the driving and/or driven equipment.Įach type of coupling has some advantage over another type. This assures that the coupling will fail before something more costly breaks elsewhere along the drive train. One is to provide a break point between driving and driven shafts that will act as a fuse if a severe torque overload occurs. In certain cases, flexible couplings are selected for other protective functions as well. If not properly compensated, minor shaft misalignment can result in unnecessary wear and premature replacement of other system components.

Even with very good initial shaft alignment there is often a tendency for the coupled equipment to “drift” from its initial position, thereby causing further misalignment of the shafts. The coupling will, to varying degrees, minimize the effect of misaligned shafts. Such compensation is vital because perfect alignment of two shafts is extremely difficult and rarely attained. Belt, chain, gear and clutch drives also transmit power from one shaft to another, but not necessarily at the same RPM and not with the shafts in approximately the same line. The second is to compensate for minor amounts of misalignment and random movement between the two shafts. The first is to transmit power (torque) from one shaft to the other, causing both to rotate in unison, at the same RPM. A flexible coupling connects two shafts, end-to-end in the same line, for two main purposes.

Sae 6b spline shaft dimensions