About Shaft Couplings
A shaft coupling is a mechanical part that connects the travel shaft and driven shaft of a motor, etc., so as to transmit ability. Shaft couplings present mechanical flexibility, rendering tolerance for shaft misalignment. Consequently, this coupling versatility can reduce uneven use on the bearing, products vibration, and additional mechanical troubles because of misalignment.
Shaft couplings can be purchased in a tiny type mainly for FA (factory automation) and a big casting type used for large power transmission such as in wind and hydraulic electrical power machinery.
In NBK, the former is named a coupling and the latter is named a shaft coupling. Below, we will talk about the shaft coupling.
Why Do We Need Shaft Couplings?
Even if the engine and workpiece are immediately connected and appropriately fixed, slight misalignment can occur over time due to changes in temperature and changes over an extended period of time, creating vibration and damage.
Shaft couplings serve while an important link to minimize impact and vibration, allowing smooth rotation to be transmitted.
Flexible Flanged Shaft Couplings
Characteristics
These are the most popular flexible shaft couplings in Japan that adhere to JIS B 1452-1991 “Flexible flanged shaft couplings”.
A simple structure manufactured from a flange and coupling bolts. Easy to set up.
The bushing between the flange and coupling bolts alleviates the consequences of torque fluctuation and impacts during startup and shutdown.
The bushing could be replaced by just removing the coupling bolt, enabling easy maintenance.
Permits lateral/angular misalignment, and reduces noise. Prevents the thrust load from being transmitted.
2 types can be found, a cast iron FCL type and a carbon steel?FCLS type Flexible Shaft Couplings
Shaft Coupling Considerations
In choosing couplings a designer first needs to consider motion control varieties or power transmission types. Most action control applications transmit comparatively low torques. Power transmitting couplings, in contrast, are designed to carry moderate to huge torques. This decision will narrow coupling choice somewhat. Torque tranny along with optimum permissible parallel and angular misalignment values will be the dominant considerations. Most couplings will publish these values and using them to refine the search should make deciding on a coupling style less complicated. Optimum RPM is another essential attribute. Optimum axial misalignment could be a consideration as well. Zero backlash is an important consideration where feedback is utilized as in a action control system.
Some power tranny couplings are designed to operate without lubricant, that can be a plus where maintenance is a concern or difficult to execute. Lubricated couplings often require covers to keep the grease in. Various couplings, including chain, gear, Oldham, etc., can be found either seeing that lubricated metal-on-metal varieties and as metallic and plastic-type hybrids where usually the coupling element is made from nylon or 
another plastic to remove the lubrication requirements. You will find a reduction in torque capability in these unlubricated varieties compared to the more conventional designs.
Important Attributes
Coupling Style
Most of the common designs have been described above.
Maximum RPM
The majority of couplings have a limit on their maximum rotational rate. Couplings for high-acceleration turbines, compressors, boiler feed pumps, etc. usually require balanced models and/or balanced bolts/nuts allowing disassembly and reassembly without increasing vibration during operation. High-speed couplings can also exhibit windage results in their guards, which can bring about cooling concerns.
Max Transmitted Horsepower or perhaps Torque
Couplings tend to be rated by their maximum torque capability, a measurable quantity. Ability is normally a function of torque moments rpm, therefore when these values are stated it is usually at a specified rpm (5HP @ 100 rpm, for instance). Torque values will be the more commonly cited of the two.
Max Angular Misalignment
Among the shaft misalignment types, angular misalignment capacity is usually stated in degrees and represents the maximum angular offset the coupled shafts exhibit.
Max Parallel Misalignment
Parallel misalignment capacity is usually given in linear models of inches or millimeters and represents the maximum parallel offset the coupled shafts exhibit.
Max Axial Motion
Occasionally called axial misalignment, this attribute specifies the maximum permissible growth between your coupled shafts, presented generally in inches or millimeters, and can be caused by thermal effects.