About Shaft Couplings
A shaft coupling is a mechanical part that connects the travel shaft and driven shaft of a electric motor, etc., to be able to transmit electrical power. Shaft couplings present mechanical flexibility, featuring tolerance for shaft misalignment. Because of this, this coupling versatility can reduce uneven dress in on the bearing, equipment vibration, and different mechanical troubles because of misalignment.
Shaft couplings can be purchased in a small type mainly for FA (factory automation) and a large casting type used for large power transmitting such as in wind and hydraulic electrical power machinery.
In NBK, the former is named a coupling and the latter is called a shaft coupling. In this article, we will discuss the shaft coupling.
Why Do WE ARE IN NEED OF Shaft Couplings?
Even if the electric motor and workpiece are immediately connected and correctly fixed, slight misalignment may appear over time because of improvements in temperature and improvements over an extended period of time, leading to vibration and damage.
Shaft couplings serve seeing that an important link to minimize influence and vibration, allowing even rotation to end up being transmitted.
Flexible Flanged Shaft Couplings
Characteristics
These are the most famous flexible shaft couplings in Japan that comply with JIS B 1452-1991 “Flexible flanged shaft couplings”.
A simple structure made of a flange and coupling bolts. Easy to install.
The bushing between the flange and coupling bolts alleviates the effects of torque fluctuation and impacts during startup and shutdown.
The bushing can be replaced by just removing the coupling bolt, enabling easy maintenance.
Permits lateral/angular misalignment, and reduces noise. Prevents the thrust load from currently being transmitted.
2 types can be found, a cast iron FCL type and a carbon metal?FCLS type Flexible Shaft Couplings
Shaft Coupling Considerations
In selecting couplings a designer first needs to consider motion control varieties or power transmission types. Most action control applications transmit comparatively low torques. Power transmission couplings, in contrast, are designed to carry moderate to substantial torques. This decision will narrow coupling choice relatively. Torque transmitting along with maximum permissible parallel and angular misalignment values will be the dominant considerations. Most couplings will publish 
these values and with them to refine the search should help to make picking a coupling style a lot easier. Optimum RPM is another significant attribute. Optimum axial misalignment could be a consideration aswell. Zero backlash is normally an essential consideration where responses is employed as in a motion control system.
Some power transmitting couplings are created to operate without lubricant, that can be a plus where maintenance is a problem or difficult to perform. Lubricated couplings generally require covers to keep carefully the grease in. Many couplings, including chain, gear, Oldham, etc., can be found either as lubricated metal-on-metal varieties and as steel and plastic-type material hybrids where generally the coupling element is constructed of nylon or another plastic material to get rid of the lubrication requirements. There exists a reduction in torque capacity in these unlubricated varieties compared to the more conventional designs.
Important Attributes
Coupling Style
Almost all of the common types have been described above.
Maximum RPM
Many couplings have a limit on the maximum rotational swiftness. Couplings for high-velocity turbines, compressors, boiler feed pumps, etc. usually require balanced models and/or balanced bolts/nuts to permit disassembly and reassembly without increasing vibration during procedure. High-speed couplings can also exhibit windage results in their guards, which can lead to cooling concerns.
Max Transmitted Horsepower or Torque
Couplings tend to be rated by their optimum torque capacity, a measurable quantity. Ability is definitely a function of torque moments rpm, therefore when these values are stated it is often at a specific rpm (5HP @ 100 rpm, for example). Torque values are the more commonly cited of the two.
Max Angular Misalignment
One of the shaft misalignment types, angular misalignment capability is usually stated in degrees and represents the utmost angular offset the coupled shafts exhibit.
Max Parallel Misalignment
Parallel misalignment capacity is usually given in linear products of inches or millimeters and represents the maximum parallel offset the coupled shafts exhibit.
Max Axial Motion
At times called axial misalignment, this attribute specifies the maximum permissible growth between the coupled shafts, provided generally in inches or millimeters, and may be caused by thermal effects.