Lubrication myth #1: Re-lubrication once a year is sufficient 每 FALSE.
Start by reviewing the bearing manufacturer＊s lubrication recommendations. These will give amounts and intervals as suggested starting points, but actual lubrication intervals may vary quite a bit, depending on load, speed, temperature, or environmental conditions. Applications with higher speeds, temperatures, or heavy contamination sometimes require frequent re-lubrication, possibly weekly or daily. By contrast, a mounted ball bearing in a lightly loaded, low-speed, clean environment may do fine with re-lubrication at 12 to 24 month intervals. Certain applications may need to be monitored and lubrication intervals/amounts adjusted accordingly.
Re-lubrication replenishes grease when the current grease breaks down or deteriorates because the base oil breaks down due to temperature. Without this, the lubricating property is gone and the result is metal-to-metal contact. Re-lubricating the bearing replenishes the oil, maintaining the proper film.
Pumping new grease into a bearing also helps flush away contamination. Many mounted bearings are designed to allow grease to enter the bearing cavity as close to the rolling elements as possible. As more grease is added, the old grease is pushed out of the seals. The purged grease carries out contaminants and keeps dirt away from the seals.
Before lubricating a bearing, make sure the grease fitting is clean, so contamination is not introduced into the bearing during re-lubrication.
Lubrication myth #2: Always add grease until it purges from the seal 每 FALSE.
If you pump grease into the bearing until it purges out the seal, you probably have completely filled the bearing cavity. Excess grease can increase operating temperature and may create enough pressure to blow the seal out. However, in low-speed or dirty conditions where contamination may easily enter the seals, filling a bearing with grease may help improve performance. Application experience will dictate when the entire bearing cavity should be filled.
Lubrication myth #3: If a bearing makes noise, grease should be added 每 FALSE.
If a bearing is making noise, internal damage has likely occurred. This increases over time, with the potential for catastrophic failure. Adding grease may provide temporary relief, but a noisy bearing should be closely monitored and replaced at the first opportunity. The root of the failure should also be investigated either with independent or manufacturer failure analysis (Manufacturer analysis requires removal of the bearing as soon as possible to aid in a more accurate diagnosis of the problem).
Lubrication myth #4: Any grease will do 每 FALSE.
Greases do differ. Some may be incompatible because of the different thickeners (soaps) used. When two incompatible greases are mixed, they may thicken and harden or become thin and leak out of the bearing. For example, many electric motors use a polyuria thickener while some mounted ball bearings use lithium-complex thickeners. These greases are borderline compatible, and depending on the actual make up, may not work together. Grease types can also be incompatible based on the viscosity or type of oil in the grease, so consulting a lubrication supplier is always recommended.
Lubrication myth #5: Just shoot grease through the fitting 每 FALSE.
Always clean grease fittings and the grease gun tip. It＊s good practice to put the grease gun tip in an oil bath or wrap it with a plastic cover to protect it.