bearing-and-their-types.pdf

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    Danial Sohail

    ME-089Assignment # 1

    Machine Design Practical  –   ME-305

    Third year –  Mechanical Engineering Department NED University of Engineering and Technology

    e a r i n g s

    A bearing is a device that is used to enable rotational or linear movement, while

    reducing friction and handling stress. Resembling wheels, bearings literally enable

    devices to roll, which reduces the friction between the surface of the bearing and

    the surf ace it’s rolling over. It’s significantly easier to move, both in a rotary or

    linear fashion, when friction is reduced this also enhances speed and efficiency.

    Types of Bearings:

    Different application require bearings that are designed to handle a specific type of

    load, normally bearings are designed to handle Radial  or Thrust  load or a

    combination of two.

    A radial load, as in a pulley, simply puts weight on the bearing in a manner that

    causes the bearing to roll or rotate as a result of tension.

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    Thrust loads are force that is applied parallel to the bearing's axis. They are also

    called axial or linear loads.

    Depending upon applications described above, bearing can be divided into

    following types,  the differences between types of bearings concern load type and

    ability to handle weight.

      Ball bearings

     

    Roller bearings

     

    Ball thrust bearings

      Roller thrust bearings

      Tapered roller bearings

      Specialized bearings

    Ball Bearing:Ball bearings are extremely common because they can handle both radial and

    thrust loads, but can only handle a small amount of weight. They are found in

    a wide array of applications, such as roller blades and even cycles, but are

    prone to deforming if they are overloaded.

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    Ball Bearing Ball Bearing in cycle rim

    Roller Bearing:

    Roller bearings are designed to carry heavy loads the primary roller is a cylinder,

    which means the load is distributed over a larger area, enabling the bearing to

    handle larger amounts of weight. This structure, however, means the bearing can

    handle primarily radial loads, but is not suited to thrust loads. For applications

    where space is an issue, a needle bearing can be used. Needle bearings work with

    small diameter cylinders, so they are easier to fit in smaller applications.

    Roller Bearing Roller bearing in gear box

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    Ball Thrust Bearing:

    These kinds of bearings are designed to handle almost exclusively thrust loads in

    low-speed low-weight applications. Bar stools, for example, make use of ball

    thrust bearings to support the seat.

    Ball Thrust Bearing Schematic Showing Ball Thrust Bearing in Stool

    Roller Thrust Bearing:

    Roller thrust bearings, much like ball thrust bearings, handle thrust loads. The

    difference, however, lies in the amount of weight the bearing can handle: rollerthrust bearings can support significantly larger amounts of thrust load, and are

    therefore found in car transmissions, where they are used to support helical gears.

    Gear support in general is a common application for roller thrust bearings.

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    Roller Thrust Bearing Roller Thrust Bearing in Car Transmission

    Tapered Roller Bearing:

    This style of bearing is designed to handle large radial and thrust loads — as a result

    of their load versatility, they are found in car hubs due to the extreme amount of

     both radial and thrust loads that car wheels are expected to carry.

    Tapered roller bearing

    Schematic showing thrust and radial load on tapered roller bearings in car hubs

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    Specialized Bearings:

    There are, of course, several kinds of bearings that are manufactured for specific

    applications, such as magnetic bearings and giant roller bearings.

      Magnetic Bearings:

    Magnetic bearings are found in high-speed devices because it has no moving parts

    this stability enables it to support devices that move unconscionably fast.

    Magnetic Bearing

      Giant Roller Bearings:

    Giant roller bearings are used to move extremely large and heavy loads, such as

     buildings and large structural components.

    Giant Roller Bearing working principle as used in Earthquake proofing