About Shaft Couplings

A shaft coupling is a mechanical aspect that connects the drive shaft and driven shaft of a motor, etc., to be able to transmit electric power. Shaft couplings bring in mechanical flexibility, offering tolerance for shaft misalignment. Due to this fact, this coupling flexibility can reduce uneven dress in on the bearing, devices vibration, and additional mechanical troubles due to misalignment.

Shaft couplings are available in a little type mainly for FA (factory automation) and a large casting type used for large power tranny such as for example in wind and hydraulic electricity machinery.
In NBK, the former is called a coupling and the latter is called a shaft coupling. Here, we will talk about the shaft coupling.
Why Do We Need Shaft Couplings?
Even if the electric motor and workpiece are immediately connected and effectively fixed, slight misalignment can occur over time because of alterations in temperature and changes over a long period of time, causing vibration and damage.
Shaft couplings serve when an important link to minimize impact and vibration, allowing soft rotation to become 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 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 simply by removing the coupling bolt, enabling easy maintenance.
Permits lateral/angular misalignment, and reduces noise. Prevents the thrust load from simply 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 selecting couplings a designer 1st must consider motion control varieties or power transmission types. Most action control applications transmit comparatively low torques. Power transmission couplings, in contrast, are made to carry average to huge torques. This decision will narrow coupling choice somewhat. Torque transmission along with maximum permissible parallel and angular misalignment values will be the dominant considerations. Many couplings will publish these ideals and using them to refine the search should make picking a coupling style much easier. Maximum RPM is another crucial attribute. Maximum axial misalignment may be a consideration as well. Zero backlash is usually a crucial consideration where responses is utilized as in a movement control system.
Some power transmitting couplings are designed to operate without lubricant, which is often a plus where maintenance is a problem or difficult to perform. Lubricated couplings typically require covers to keep the grease in. Many couplings, including chain, equipment, Oldham, etc., are available either while lubricated metal-on-metal varieties and as metallic and plastic-type hybrids where generally the coupling element is constructed of nylon or another plastic to get rid of the lubrication requirements. There exists a reduction in torque ability in these unlubricated varieties compared to the more conventional designs.
Important Attributes
Coupling Style
Most of the common variations have already been described above.
Maximum RPM
The majority of couplings have a limit on their maximum rotational swiftness. Couplings for high-quickness turbines, compressors, boiler feed pumps, etc. generally require balanced styles and/or balanced bolts/nuts to permit disassembly and reassembly without increasing vibration during operation. High-speed couplings can also exhibit windage effects in their guards, which can result in cooling concerns.
Max Transmitted Horsepower or perhaps Torque
Couplings are often rated by their maximum torque capability, a measurable quantity. Electrical power is definitely a function of torque occasions rpm, and so when these values are stated it is often at a specific rpm (5HP @ 100 rpm, for instance). Torque values are the additionally cited of the two.
Max Angular Misalignment
One of the shaft misalignment types, angular misalignment ability is usually explained in degrees and represents the maximum angular offset the coupled shafts exhibit.
Max Parallel Misalignment
Parallel misalignment capacity is generally given in linear units 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 utmost permissible growth between the coupled shafts, offered generally in inches or perhaps millimeters, and may be caused by thermal effects.