If you want to increase the life of the gear couplings in your machine, then proper lubrication is the only way. Remember, periodic lubrication is the secret to long lasting couplings. However, choosing the right lubrication is also important and the principles of lubricant properties and gear wear should be kept in mind too.
The advantages and disadvantages of gear couplings
Before you get to know about the right kind of lubrication needed for gear couplings, you must know the advantages first. Some of the advantages of using gear couplings are:
- Gear couplings can send more power per inch of diameter and per pound than any other coupling.
- Even if you mishandle them or improperly install them, gear couplings will go on giving satisfactory service
- They are safer and consistent
- The only disadvantage is wearing of the teeth, which takes place gradual in process. Complete worn out of the teeth will only result in power loss.
How does a lubricant work on gear couplings?
The force generated by mating teeth along with the oscillatory motion generally wipes off the lubrication from the surface of contact. When one tooth slides in one direction, the lubricant wets the uncovered area behind the tooth. To do this, the lubricant has to work against both the short time in between one cycle and its own viscosity. The centrifugal forces created by the rotational speed of the gear couplings lubricate the teeth operation.
Grease as a lubricant
Oil and grease must be compared on the basis of convenience and lubrication properties. The very first thing that you should know is that grease is a type of oil in which a thickening agent has been added. The biggest benefit of using grease is that they are sealed easily and don't drip from the place where lubricant is needed.
Grease is focused to a small centrifugal force and that is why, it needs time to flow in the voids within the teeth. But centrifugal forces have greater effect on grease thickeners because the thickeners have high specific density. For proper maintenance of the gear couplings, it is very important for you to understand the working of grease in coupling because, although the gear coupling may be full of grease, it may be lacking lubrication.
To choose the right grease for your machine, take the advice of coupling manufacturers who generally depend on field experience and lab tests. But that doesn't mean that any grease not recommended by experts would be a bad option. So, when you choose grease, your choice should be based on certain facts, like:
- Grease should contain more than 92 percent of oil.
- Any good quality grease should have an oil base with high viscosity.
- It should also oppose centrifugal separation.
There is some grease that includes special fillers or additives. Studies have proved that EP additives are very good for loaded gear couplings as well as other couplings in the time of breaking-in. Other additives like high density compounds including molybdenum disulfide and lead are good during low speed and high load usage.