About Shaft Couplings
A shaft coupling is a mechanical element that connects the drive shaft and driven shaft of a electric motor, etc., as a way to transmit electric power. Shaft couplings present mechanical flexibility, rendering tolerance for shaft misalignment. Because of this, this coupling overall flexibility can reduce uneven dress in on the bearing, tools vibration, and various other mechanical troubles due to misalignment.
Shaft couplings can be found in a little type mainly for FA (factory automation) and a big casting type used for huge power transmission 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. Below, we will talk about the shaft coupling.
Why Do We Need Shaft Couplings?
Even if the engine and workpiece are directly connected and appropriately fixed, slight misalignment can occur over time because of alterations in temperature and changes over a long period of time, creating vibration and damage.
Shaft couplings serve because an important link to minimize effects and vibration, allowing simple rotation to be 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 manufactured from a flange and coupling bolts. Easy to install.
The bushing between your flange and coupling bolts alleviates the consequences of torque fluctuation and impacts during startup and shutdown.
The bushing can be replaced simply by removing the coupling bolt, enabling easy maintenance.
Permits lateral/angular misalignment, and reduces sound. Prevents the thrust load from being transmitted.
2 types are available, a cast iron FCL type and a carbon metal?FCLS type Flexible Shaft Couplings
Shaft Coupling Considerations
In choosing couplings a designer 1st needs to consider motion control varieties or power transmission types. Most motion control applications transmit comparatively low torques. Power tranny couplings, in contrast, are designed to carry average to great torques. This decision will narrow coupling choice somewhat. Torque transmission along with optimum permissible parallel and angular misalignment values are the dominant considerations. The majority of couplings will publish these ideals and using them to refine the search should help to make picking a coupling style easier. Optimum RPM is another vital attribute. Maximum axial misalignment could be a consideration aswell. Zero backlash can be an important consideration where opinions can be used as in a movement control system.
Some power transmission couplings are designed to operate without lubricant, which is often a plus where maintenance is a problem or difficult to execute. Lubricated couplings quite often require includes to keep carefully the grease in. Many couplings, including chain, gear, Oldham, etc., are available either seeing that lubricated metal-on-metal kinds and as metal and plastic material hybrids where usually the coupling element is constructed of nylon or another plastic-type material to remove the lubrication requirements. You will find a reduction in torque capacity in these unlubricated forms compared to the more conventional designs.
Important Attributes
Coupling Style
Almost all of the common models have already been described above.
Maximum RPM
The majority of couplings have a limit on the maximum rotational rate. Couplings for high-velocity turbines, compressors, boiler feed pumps, etc. usually require balanced patterns and/or balanced bolts/nuts to permit disassembly and reassembly without increasing vibration during procedure. High-speed couplings may also exhibit windage results in their guards, which can bring about cooling concerns.
Max Transmitted Horsepower or perhaps Torque
Couplings are often rated by their optimum torque ability, a measurable quantity. Electric power is normally a function of torque situations rpm, and so when these ideals are stated it is often at a specific rpm (5HP @ 100 rpm, for 
example). Torque values are the more commonly cited of both.
Max Angular Misalignment
One of the shaft misalignment types, angular misalignment capability is usually mentioned in degrees and represents the maximum angular offset the coupled shafts exhibit.
Max Parallel Misalignment
Parallel misalignment capacity is normally given in linear models 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 utmost permissible growth between your coupled shafts, offered generally in inches or perhaps millimeters, and will be caused by thermal effects.