Falk couplings are common components in any mechanical drive system. A variety of Falk couplings are available, including gear, grid, disc, elastomeric, fluid and composite. Couplings require periodic maintenance, and regular inspection will provide clues to help improve the life of a Falk coupling.
Signs of coupling failure include leakage (indicating seal failure), excessive noise (indicating wear or loose parts) and excessive vibration (indicating unbalanced or loose parts). Falk couplings should also be inspected at regular intervals for signs of problems visible on external components.
Determining the Cause of Coupling Failure
When Falk couplings are disassembled, it is possible to inspect the internal parts for wear or damage. This may not normally be done for maintenance, but if a coupling fails, it can be helpful in determining the causes so a replacement part may be selected that is better suited to the requirements of the system.
Typical failures of Falk coupling components due to overloading or improper component selection include the following:
- Ruptured flexible elements (overloads due to improper selection or increased loads).
- Split hub (improper selection).
- Burst hub (improper selection and overloading).
- Key roll (improper selection).
- Elongated bolt holes (excessive torsional vibration and overloading).
Lack of maintenance will result in accelerated wear and early failure of the Falk coupling. Lubrication failures due to lack of maintenance or damage will cause failures evidenced by signs such as:
- Gear tooth damage (poor lubrication and alignment).
- Cracked flexible element (lubrication contamination leading to hardening).
- Fatigue cracks in gears and other parts (sludge buildup leading to reduced flexibility of coupling).
- Component discoloration (lack of lubrication leading to component heating).
- Fretting corrosion (improper or contaminated lubricants).
Following the recommended inspection and maintenance schedule for a Falk coupling will help provide the best service life. Normal maintenance does not involve balancing, as this is part of the manufacture of coupling components. However, unbalance can develop in an existing system and can shorten the life of a Falk coupling, so maintenance should involve inspection for signs of unbalance. Rebalancing involves determining where extra weight should be added or removed to the rotating assembly and is generally a specialized procedure done at installation if the coupling is used in a high-speed or precision application or if the problem develops during use.
If repair does become necessary, repair parts and kits for Falk couplings are always available from the manufacturer. This can help provide the greatest life and best operation from the coupling and the complete mechanical system.
Posted under Machinery Maintenance on Thursday, November 3rd, 2011