Before resorting to a Google search or assuming this topic has already been discussed extensively on other forums, please take the time to read the entire post. It appears that there is conflicting information regarding whether or not double shielded bearings need to be greased. While some bearing salesmen claim it is unnecessary, most motor manufacturers recommend greasing them. This disparity is evident in online forum discussions as well, with about half advocating for greasing and the other half advising against it. Despite this ongoing debate, it is puzzling why there isn't a definitive answer to this question. In the meantime, I have decided to err on the side of caution by greasing all double shielded bearings in motors exceeding 10hp. I will also be removing grease fittings from all other bearings unless persuaded otherwise. Your insights on this matter are greatly appreciated!
Consider conducting an experiment to determine the type of grease typically found in a standard shielded bearing used in motors. After installing the bearing, inject a large amount of differently colored grease through the grease fitting, then disassemble the motor to observe the distribution of the grease. It is unlikely that the new grease will penetrate the shield, possibly resulting in the bearing functioning like a hydraulic cylinder. While I have not personally attempted this experiment, I am curious to learn about the outcome.
Supporters of greasing shielded bearings argue that the oils within the grease gradually penetrate the small holes in the shields, ultimately prolonging the life of the grease inside the bearing. This makes it challenging to definitively disprove this theory through testing. Thank you for your input.
If they can offer any corroborating evidence to substantiate their theory, I would appreciate it. Ultimately, the burden of proof lies on them.
In the 1970s and 1980s, it was common practice to remove a shield for greasing purposes, which was effective at the time.
Determining whether to relubricate bearings is a decision that depends on various factors. Relubrication can help replenish the grease inside the mechanism by allowing fresh oil to creep through the clearance. However, the effectiveness of relubrication may vary, especially in open bearings. Factors such as size, speed, and runtime play a crucial role in deciding whether to relubricate. Larger and high-speed bearings tend to deplete oil faster, making relubrication more necessary. On the other hand, small bearings in infrequently used motors may not require frequent relubrication. While double-shielded bearings are often considered "lubricated for life," it's important to note that the grease has a finite lifespan. SKF recommends expecting a grease life for double-shielded bearings to be approximately twice the relubrication interval indicated on charts. EPRI suggests relubricating double-shielded bearings half as often as single-shielded bearings to prevent shields from crushing into the bearings due to overfilling. Monitoring vibration and audible noise can help determine when relubrication is needed. Ultimately, the decision to relubricate bearings should be based on a careful assessment of the specific machine group, considering factors such as size, speed, and usage patterns.
I think you're right to err on the side of caution. It's really down to the specific application and conditions, so there's not going to be a one-size-fits-all answer. A lot of the time, double shielded bearings come pre-lubricated from the factory and shouldn't need extra grease. However, for applications in high heat or heavy-duty environments, additional greasing may extend the bearing's lifespan. Again, manufacturer recommendations are probably your safest bet. So, definitely worthwhile to grease those larger power motors!
This is a very thought-provoking question, and I can understand why there is so much conflicting advice out there. In my experience, even though double shielded bearings are designed to be maintenance-free, it doesn't necessarily mean they won't benefit from additional greasing. The point here is not to forget that too much grease could also harm bearings due to increased heat caused by churning. Therefore, I, personally, follow the manufacturer's instructions closely and when in doubt, I reach out to them directly. It's always better to get clarification from your bearing supplier or the motor manufacturer.
I totally get the confusion around double shielded bearings; it seems like there’s a lot of varying opinions out there! From my experience, greasing them can help extend their lifespan, especially in high-demand applications, but I’ve also found that over-greasing can lead to issues, so finding that sweet spot is key. It sounds like you’re taking a sensible approach by greasing your larger motors and opting to remove fittings on the others—you might find that works really well. If you’re still unsure, maybe performing a few tests on the specific types of bearings you use could help clarify what works best for your setup.
It’s definitely a confusing topic! My understanding is that while many double shielded bearings come pre-lubricated for their intended lifespan, they can sometimes benefit from additional grease—especially under heavy load or in dusty environments. It ultimately might come down to the specific application and manufacturer guidelines, so it sounds wise to follow your instincts and grease those high-power motors. Also, considering what you use the equipment for could guide your decision about grease fittings—if you think you’ll need to maintain flexibility, it might be worth keeping them on. Curious to hear what others think!
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Answer: Answer: There is conflicting information on whether double shielded bearings need to be greased. Some claim it is unnecessary, while others recommend greasing them. The debate continues with varying opinions.
Answer: Answer: While some bearing salesmen may say greasing is unnecessary, most motor manufacturers recommend greasing double shielded bearings. This disparity in recommendations adds to the ongoing debate.
Answer: Answer: Online forums show that about half of the discussions advocate for greasing double shielded bearings, while the other half advises against it. This split in opinions further contributes to the lack of a definitive answer on this topic.
Answer: Answer: As there isn't a clear consensus, individuals may choose to err on the side of caution by greasing all double shielded bearings in motors exceeding 10hp. Personal preferences and insights from others in the industry can also inform decision-making.
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