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Imagine a bearing which is contained in a cast iron mounting bracket, which also works as an external housing for bearing and you have what is known as a pillow block bearing. The housing for such bearing, usually made from grey cast iron, is fashioned to get fastened tightly with help of bolts. The inner part of a pillow block bearing is made of a softer metal, often white metal, though the outer housing may be single or designed to split. Largely, it is meant for applications having very small load and torque. It is meant for use in those areas of an industrial unit which have clean surroundings. Though in some countries a pillow block bearing is considered to be the same as a plummer block bearing, these two are not identical. The main difference is that a plummer block bearing has no inner bearing. This housing is for bearings, meant for use in applications having heavy loads, under corrosive environs of industrial units. The common design feature of the two kinds of bearing housing is that you can secure the housing to any stable surface with help of bolts at the bottom of the assembly and passing through holes already forming a part of the casting. Pillow block bearing is employed for supporting spinning shafts to keep them stable. The housing of bearing is fashioned to have especially made seals at its exit and entrance to keep the bearing free from pollutants like dust and dirt. Split housing is employed for applications needing frequent bearing changes and offers easy maintenance. Certain applications require one piece or un-split housing, for instance when shaft speed is very low or if access is restricted or difficult. This design is recommended when shaft speed is low and maintenance is not needed so frequently. Roller Bearing Roller bearing are spherical or cylindrical device that facilitates movement of components, which are generally heavy or big. Like any other bearing, in their case too the function is to minimize friction for moving parts or items. These are frequently used in machines and industrial items such as conveyer belts to help an even and efficient movement of goods. The design of such bearings allows them to have number of contact points within a circular housing having rolling parts within it. An example will be of bearings ball assembled in a collar. To understand the working of roller bearings, consider a large and heavy block of wood that you need to move along any surface. Because of its weight, it needs to be dragged, requiring a lot of effort plus time. Now, imagine the same block riding over a couple of cylindrical pipes! It moves quite easily now as friction between the wooden block and the surface on which it moves got reduced due round pipes. You get roller bearing in varied designs and specifications for various machines and applications. Cylindrical roller bearing comprises of a metallic collar, containing a smaller, toothed wheel within. The inside of the wheel contains ball bearings which are kept in position by the teeth provided over the wheel. While the load moves , the wheel rotates, though the weight of the load continues to be on spherical ball bearings within the cylinder. Though the design of roller bearings is generally simple, it can be quite complex in certain cases, depending on the application. The most basic form is a bearing kept beneath a weighty product. Roller bearings of this type are frequently used in many machines such as conveyer belts.
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pillow block bearings, roller bearings,
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