About Shaft Couplings
A shaft coupling is a mechanical element that connects the drive shaft and driven shaft of a engine, etc., so that you can transmit electric power. Shaft couplings introduce mechanical flexibility, rendering tolerance for shaft misalignment. Therefore, this coupling versatility can reduce uneven use on the bearing, apparatus vibration, and various other 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 huge power tranny such as in wind and hydraulic electricity machinery.
In NBK, the former is named a coupling and the latter is named 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 straight connected and appropriately fixed, slight misalignment can occur over time due to adjustments in temperature and improvements over a long period of time, causing vibration and damage.
Shaft couplings serve since an important link to minimize effects and vibration, allowing clean rotation to always be transmitted.
Flexible Flanged Shaft Couplings
These are the most popular 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 the 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 noises. Prevents the thrust load from staying transmitted.
2 types are available, 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 motion control applications transmit comparatively low torques. Power transmission couplings, in contrast, are created to carry average to huge torques. This decision will narrow coupling choice somewhat. Torque transmitting along with optimum permissible parallel and angular misalignment values are the dominant considerations. Most couplings will publish these ideals and using them to refine the search should make deciding on a coupling style simpler. Maximum RPM is another critical attribute. Maximum axial misalignment may be a consideration as well. Zero backlash is usually a significant consideration where feedback is used as in a action control system.
Some power tranny couplings are designed to operate without lubricant, which is often an advantage where maintenance is a concern or difficult to execute. Lubricated couplings often require includes to keep carefully the grease in. A large number of couplings, including chain, gear, Oldham, etc., are available either as lubricated metal-on-metal types and as metal and plastic-type hybrids where usually the coupling element is made from nylon or another plastic-type material to remove the lubrication requirements. You will find a reduction in torque potential in these unlubricated forms when compared to more conventional designs.
Almost all of the common types have been described above.
Many couplings have a limit on the maximum rotational swiftness. Couplings for high-velocity turbines, compressors, boiler feed pumps, etc. generally require balanced patterns and/or balanced bolts/nuts allowing disassembly and reassembly without raising vibration during operation. High-speed couplings can also exhibit windage effects in their guards, which can result in cooling concerns.
Max Transmitted Horsepower or Torque
Couplings are often rated by their maximum torque potential, a measurable quantity. Power is a function of torque instances rpm, thus when these values are stated it is generally at a specific rpm (5HP @ 100 rpm, for instance). Torque values will be the additionally cited of the two.
Max Angular Misalignment
One of the shaft misalignment types, angular misalignment ability is usually stated in degrees and represents the maximum angular offset the coupled shafts exhibit.
Max Parallel Misalignment
Parallel misalignment capacity is normally given in linear systems 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, offered generally in inches or perhaps millimeters, and will be caused by thermal effects.