Spherical Roller Bearings
Spherical roller bearings are used in a wide variety of heavy-duty industrial applications. These bearings are known for their outstanding load capacity, self-aligning ability and high tolerance for shock loads. However, the performance and load carrying capacity of these bearings can vary depending on the bearing type and application. Some types are designed to be speed-limited while others can handle heavy loads and large radial loads.
One of the major differences between spherical roller bearings and other types of rolling-element bearings is their internal structure. Spherical roller bearings use two rows of barrel-shaped rollers. The inner ring has dual raceways, while the outer ring has one. Typically, the outer ring has a hardened guide ring centered in the raceway. This structure helps ensure that the inner and outer rings are accurately aligned and provide a smooth rotation.
The outer ring also typically has a guide channel. Besides providing alignment, these channels help to reduce fluttering and noise. Rollers are usually made from stainless steel or brass, but they can also be manufactured from polyamide or machined steel. They can be lubricated with oil or grease, or a combination of these. It is important to choose the appropriate lubricant based on the load being carried and the operating environment. If the operating temperature is very high, you might want to consider choosing a bearing with a PTFE coated cylindrical bore.
Spherical roller bearings are available in many different designs and sizes. For example, NSK offers a range of sealed spherical roller bearings with a high-performance window-type pressed steel cage. Alternatively, you can select a cage made of a special material to meet your application needs.
ULTAGE spherical roller bearings combine optimized internal and external design, allowing for improved lubrication flow and increased service life. They also offer up to 20% better limiting speeds than conventional bearings. Aside from their superior load capacities, they also have the lowest operating temperatures, offering the ultimate in service life.
Some spherical roller bearings are also available in tapered bores, which can help mount them directly on tapered shafts. In order to properly mount the bearing, the shaft must be a good fit and the setscrew must be tightened. Similarly, the bearing cover must be lubricated with a grease that will be suitable for the load being carried. Grease-lubricated bearings must be selected carefully because grease has a lower speed capacity than oil. Adding a small amount of grease to the bearing covers will redistribute the grease, but it is best to limit the amount to 5% of the original charge.
To maintain a high-quality bearing, manufacturers must maintain strict quality control. It is not enough to simply have an ISO certificate. Rather, top management must ensure that the quality of the bearings being produced is maintained. Moreover, the bearing manufacturing process must be standardized to avoid misalignment or other flaws.
When deciding on a spherical roller bearing for your application, keep in mind the limiting speed of the bearing and the environment in which it will be used. Spherical roller bearings can handle a wide range of high, moderate, and low loads.
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