Bearing Block Guide
What is a Bearing Block?
A bearing block, also known as the pillow block bearing, is an extra-large pedestal that is used to support integrated bearings, and has unique structure. This bearing unit is characterized as having compact structure, sensitive rotation, and is convenient to maintain. One thing to keep in mind is that where there is a bearing, there will be a support point.
The inner support point of the bearing block is the shaft, and the outer support is often referred to as the bearing seat (or the bearing mount). The inside of the bearing is typically 0.025mm larger than the shaft to ensure tight fit. The shaft is commonly secured using locking collars, set screws or set collars. The housing material for the pillow block is normally made of cast steel and cast iron.
Characteristics of Bearing Block
The bearing block has extra-large mounting seat that can accommodate substantial loads. Compared with the conventional bearing housings, bearing blocks are known for the features shown as follows:
The dimeter of a bearing block is usually range from 0.2cm up to 10m. Some models may have diameters as long as 40m.
● Carrying Capacity:
Bearing blocks have exceptionally high carrying capacity. They are capable of withstanding axial load, radial load and overturning moment load altogether.
Bearing blocks are also known for the low speed. The operating speed is typically lower than 10r/min. And in some cases, they do not rotate one after another, but only rotates within a certain angle to make a swing movement.
● No pivot:
The inner ring or outer ring of the bearing block has a gear for rotating drive. They can be fastened on the upper and lower supports with screws on the device hole of the bearing housing.
Pillow block bearings are typically made of grey cast iron. However, they could also be made of various metals that will retain the same function. This includes ductile iron, stainless steel, steel and various other types of thermoplastics and polyethylene-based plastics. The bearing element of the pillow block bearings can also be manufactured from chromium steel alloy (being the most common), plastic, stainless steel or other bushing materials such as cast bronze or sintered bronze, or synthetic materials.
Types of Bearing Blocks
Pillow block bearings may contain a bearing with a handful of different types of rolling element, including cylindrical roller, spherical roller, tapper rolled, ball and metallic or synthetic bushing.
As a matter of fact, a type of pillow block bearing is defined by the type of rolling element incorporated. These are often confused with plumber blocks, which are bearing housings that do not actually contain any bearings, and are typically used for a separately installed bearing.
Nevertheless, the fundamental application of the different types of pillow block bearings is the same: to mount a bearing securely, allowing the outer ring to stay still as the inner ring is enabled to rotate.
A pillow block bearing is bolted to a foundation using screws through the device holes. The bearing blocks can further be broken down into two categories: the solid type and split type.
The solid type pillow block bearing is a single piece housing that allows various sealing arrangement to prevent contaminants, like dust, from getting into the bearing block. Thus, this type of pillow block bearing offers a clean environment that enables environmentally sensitive bearings to rotate without the interference of contaminants. It is also able to retain lubrication using either grease or oil, thereby enhancing the performance and duty cycle. Split type pillow block bearings, on the other hand, are typically two-piece housings where the base and the cap may be detached. It does not however have the environmentally friend nature like a solid type pillow block bearing does.
Common Problems When Using Bearing Block
One very common issue that you are likely to encounter when using a pillow block bearing is that wear and tear happen quite frequently.
Traditionally, the “surfacing technique” was usually used in attempt to repair a worn pillow block bearing. But this often leads to excessively high temperature of the surface of the pillow block bearings, causing deformation or crack of the surface. Also, such method usually has high downtime.
However, using the more modern method, where polymer composite materials are used for on-site repair does not yield thermal impact like mentioned above. And it is not limited to how thick of the surface is repairable. The modern repair method can ensure complete coordination among the repaired parts, and reduce shock and vibration to avoid the possibility of further wear. Therefore, avoid using the traditional method for any on-site repairs.
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