About Shaft Couplings
A shaft coupling is a mechanical element that connects the travel shaft and driven shaft of a motor, etc., in order to transmit ability. Shaft couplings expose mechanical flexibility, rendering tolerance for shaft misalignment. Due to this fact, this coupling versatility can reduce uneven have on on the bearing, devices vibration, and different mechanical troubles due to misalignment.
Shaft couplings can be purchased in a small type mainly for FA (factory automation) and a large casting type used for large power transmission such as in wind and hydraulic power machinery.
In NBK, the former is called a coupling and the latter is called a shaft coupling. In this article, we will talk about the shaft coupling.
Why Do We Need Shaft Couplings?
Even if the engine and workpiece are directly connected and properly fixed, slight misalignment can occur over time because of changes in temperature and alterations over an extended period of time, leading to vibration and damage.
Shaft couplings serve as an important connect to minimize effect and vibration, allowing smooth rotation to become transmitted.
Flexible Flanged Shaft Couplings
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 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 sound. Prevents the thrust load from simply 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 initial must consider motion control varieties or power transmission types. Most action control applications transmit comparatively low torques. Power transmitting couplings, in contrast, are created to carry moderate to excessive torques. This decision will narrow coupling choice somewhat. Torque transmission along with optimum permissible parallel and angular misalignment ideals are the dominant considerations. Many couplings will publish these ideals and using them to refine the search should help to make deciding on a coupling style a lot easier. Optimum RPM is another essential attribute. Optimum axial misalignment may be a consideration as well. Zero backlash is normally a significant consideration where responses can be used as in a action control system.
Some power transmission couplings are created to operate without lubricant, that can be an advantage where maintenance is a concern or difficult to perform. Lubricated couplings typically require includes to keep the grease in. Many couplings, including chain, gear, Oldham, etc., are available either seeing that lubricated metal-on-metal varieties and as metallic and plastic hybrids where usually the coupling element is constructed of nylon or another plastic-type material to get rid of the lubrication requirements. There exists a reduction in torque potential in these unlubricated forms compared to the more conventional designs.
Almost all of the common models have been described above.
Most couplings have a limit on their maximum rotational velocity. Couplings for high-velocity turbines, compressors, boiler feed pumps, etc. generally require balanced patterns and/or balanced bolts/nuts to permit disassembly and reassembly without raising vibration during procedure. High-speed couplings may also exhibit windage effects in their guards, which can result in cooling concerns.
Max Transmitted Horsepower or Torque
Couplings tend to be rated by their optimum torque ability, a measurable quantity. Electric power is a function of torque times rpm, and so when these values are stated it is usually at a specified rpm (5HP @ 100 rpm, for instance). Torque values are the more commonly cited of both.
Max Angular Misalignment
Among the shaft misalignment types, angular misalignment capability is usually mentioned 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 your coupled shafts, given generally in inches or millimeters, and can be caused by thermal effects.