How to choose a suitable bearing?

How to choose suitable mechanical bearings? Teach you to quickly understand bearings!

 

What are mechanical bearings?  

 

Mechanical bearings (Bearings), also known as bearings in the industry, are used to support the rotating shaft inside the machine to allow the machine to achieve optimal operating performance. They are an indispensable mechanical part. Mechanical bearings are widely used in a wide range of fields, including automotive industry, motors, sports equipment and other fields. For different mechanical application requirements, there will be corresponding bearing types used, such as ball bearings, linear bearings, needle bearings, etc.

 

The main functions of mechanical bearings

 

Function 1: Reduce the friction of moving parts

The unique structural design of the bearing can reduce the friction generated by the components in the machine when they transmit to each other. If the spare parts of the machine do not have bearings, the friction during operation will create noise and increase the degree of damage to the parts, significantly shortening the life cycle of the equipment.

 

Function 2: Protection and support

Bearings can provide protection and support, allowing the continuously rotating parts inside the machine to be fixed in the correct position without causing misalignment problems due to the friction and load generated during operation.

 

How to choose suitable mechanical bearings?

 

1. Shaft Diameter

In addition to the structure of the equipment, the size of the bearing is also an important consideration. The size of the shaft running in the equipment determines the size of the bearing inner diameter. The smaller the equipment shaft diameter, the smaller the corresponding bearing inner diameter (hole diameter) requirement.

  • If the shaft diameter is larger, you can choose various types of roller bearings such as cylindrical, tapered, and self-aligning.
    When the axial space is limited, a combination of ball and needle roller bearings can be selected.
  • When radial space is limited, CARB toroidal roller bearings with cages can be used, as well as the lighter and thinner series of needle roller bearings.

 

2. Load direction and magnitude

Bearing loads are divided into three types: axial load (Axial Load), radial load (Radial Load) and combined load (Combined Load). In addition to the direction of the bearing load, the load size also needs to be considered, and corresponding types of bearings are available.

  • Can withstand radial loads, and the bearing types increase according to load capacity: deep groove ball bearings, cylindrical roller bearings, needle roller bearings.
  • Bearing types that can withstand combined loads and increase in load capacity:deep groove ball bearings, block bearings, angular contact ball bearings and tapered roller bearings.

 

3. Rotation Speed

The lower the friction resistance of the bearing, the less heat it generates, and the bearing can always operate at a high speed. According to this principle, the speed of rolling bearings will be limited by the operating temperature.

  • Deep groove ball bearingsandSelf-aligning ball bearingsare the bearings with the highest rotational speeds, but individual load conditions must also be considered.

 

4. Precision

The smaller the bearing tolerance, the higher the precision. Under normal circumstances, ordinary-grade mechanical bearings can handle a variety of applications, but mechanical applications that require high-speed operation, such as racing cars, machine tools, and ship propellers, require the use of precision bearings. The current mainstream bearing accuracy standards and specifications are ABEC and ISO. For ABEC grading, the larger the number, the higher the precision; for ISO grading, the smaller the number, the higher the precision.

Source:https://en.wikipedia.org/wiki/ABEC_scale

 

5. Sealing System

The sealing system of the bearing is particularly important for the service life and working performance of the bearing, because without sealing, impurities from the outside are easily accumulated inside the bearing, such as dust, corrosive liquids and fine sand.

In addition, bearings need lubricants when they rotate, and sealed bearings can keep the lubricants inside the bearings, making the bearings run smoother and longer. For the outside of the bearing, it can also prevent the surrounding parts from being contaminated.

  • Bearings suitable for providing integral seals:deep groove ball bearings, pillow block bearings, single-row and double-row angular contact ball bearings, self-aligning ball bearings, needle roller bearings, spherical roller bearings and full complement CARB curved roller bearings.

 

6. Rigidity

The rigidity of a bearing refers to the degree of elastic deformation that occurs inside the bearing under load. The smaller the deformation, the higher the rigidity. We can apply "preload" to increase the rigidity of the bearing and reduce the occurrence of bearing deformation.

  • In general, roller bearings are more rigid than ball bearings.
  • High rigidity bearing types:plane bearings, full complement cylindrical roller bearings, tapered roller bearings, needle roller thrust bearings, spherical roller thrust bearings.

 

7. Installation and Removal

Bearing installation can be divided into separable and non-separable types; generally, the design of the inner and outer ring components of the separable cylindrical bore bearing is easier to install and disassemble frequently. Tapered bore bearings can be directly installed on tapered and cylindrical shafts with adapter sleeves and withdrawal sleeves.

  • Separable bearing types: Cylindrical roller bearings, self-aligning ball bearings, needle roller bearings.

 

Summary

The above selection criteria for mechanical bearings are not absolute standards. What is really important is that the type of bearing should correspond to the relevant application. You cannot make a blind choice based on price and brand. If you are confused about which bearing to choose, you are welcome to contact us at any time!