Gear couplings: safe and reliable

June 17, 2013 9:28 am

Gear couplings are the most versatile. Gear couplings, which are safe and reliable, operate by transmitting torque by the engagement of external teeth on the toothed hub, with the internal teeth in the sleeve. Small clearances between the internal and external teeth allow the teeth to slide and move in angular direction in relation to each other while transmitting the torque smoothly.
Feature     More power intensive: highest torque, regarding weight and bore range  Wide range    Have axial slide capability   Low-speed, high-torque capability Available with following modifications:
Shear pin coupling: protect the equipment against excessive torque   Vertical application: designed to use with vertical shafts Spacer coupling: ease of maintenance without disturbing equipment  Brake drum coupling for brake application Brake disc coupling for brake application Insulated type to eliminate the flow of stray current from shaft to shaft  Limited end float: limit axial travel of the rotor.Continuous sleeve: blind assembly and space restriction application  Floating shaft coupling for longer separation of shaftsDouble engagement coupling: accommodates parallel an angular misalignment    Single engagement: accommodates only angular misalignmentCoupling with axial float: allows predetermined axial floatMill motor coupling: suitable for mill motor frame sizes Available in different material: suitable for different environment Rigid coupling: no misalignment  Quick disconnect coupling for inching drive system.     Various heat treatments can be applied like volume, flame, induction, nitriding, etc. to improve the capacity and wear resistance of the gear coupling. Crowning with stub tooth also improves the torque carrying capacity.
When properly selected, installed, and maintained, gear coupling can provide long life and good reliability. However, question of reliability of gear coupling depends on lack of knowledge and execution of basic fundamentals which are required for reliable performance of these couplings.
Factors contributing to the reliability of the gear couplings are• Selection  All the efforts made by manufacturer to provide a good coupling and all the efforts made in selecting the right coupling for the application can be ruined by the use of wrong grease in the coupling.
• Installation To prevent the wear of tooth due to rubbing action, coupling must be lubricated.
• Lubrication     This is the most important operating factor for gear coupling from the point of reliable performance. There are two methods for lubrication of gear couplings: grease lubricated (general purpose applications) and oil lubricated (high speed applications).
• Maintenance      This is the main disadvantage of gear couplings compared with dry couplings; however these are popular and widely used. The main reason is that gear couplings can transmit more power per kilogram and per centimeter of its diameter than others. These also can continue to perform even if improperly installed or mishandled.