How Do Bearings Work？

Bearing as a “joint” of mechanical parts, for the use of machinery, machine has an important role in principle, the bearing from ancient times are being discovered, and work as a simple rotation principle, by now, in the human constant research and exploration, today’s bearing from the use of performance requirements and the use scope of work has the very big breakthrough,  Moreover, different types of bearings can be selected according to their specific use environmental conditions, so that the work can get twice the result with half the effort.

The following is a basic introduction to the working principle of bearings: 

The rolling bearing developed on the basis of bearing, its working principle is rolling friction instead of sliding friction, generally consists of two rings, a group of rolling body and a cage composed of strong universality, standardization, high degree of serialization of mechanical foundation.  Due to the different working conditions of various machines, different requirements are put forward for rolling bearings in terms of load capacity, structure and performance.  To this end, rolling bearings need a variety of structures.  However, the most basic structure is composed of an inner ring, an outer ring, a rolling body and a cage — often referred to as the four major pieces.  

For sealed bearings, plus lubricant and sealing ring (or dust cover) – also known as six pieces. 

  Various bearing types are mostly named according to the name of the rolling body.  The roles of various parts in bearings are: for centripetal bearings, the inner ring is usually closely matched with the shaft, and operates with the shaft, and the outer ring is usually transitional with the bearing seat or mechanical shell hole, playing a supporting role.  However, in some cases, there is also an outer ring running, the inner ring fixed supporting role or the inner ring, the outer ring are running at the same time.  

For thrust bearings, the bearing ring is closely matched with the shaft and moves together, and the bearing seat or mechanical shell hole into a transition match and supporting the bearing ring.  The rolling body (steel ball, roller or needle) in the bearing usually with the help of the cage evenly arranged between the two rings for rolling movement, its shape, size and number directly affect the bearing load capacity and performance.  The cage can not only evenly separate the rolling body, but also guide the rotation of the rolling body and improve the lubrication performance of the bearing.  

The components of bearings, the following small series mainly take deep groove ball bearings as an example, as shown in the figure  

          Outer ring  rolling element   cage  inner ring  Outer ring

Bearing seal  

Seals can be divided into two main categories, one is the bearing seal ring, the other is the bearing dust cover.  Bearing sealing ring is of great significance to its sealing performance and service life. The production material is rubber, mainly including: nitrile rubber, hydrogenated nitrile rubber and fluorine rubber;  And bearing dust cover is to prevent the bearing into the dust and other sundry affecting work, production materials for sheet metal, dust cover is an annular cover, usually composed of sheet metal stamping, fixed on the bearing of a ring or a washer, and extends toward another ring or washer and obscure bearing internal space, but not contact with another ring or washer.  

Bearing outer ring  

Bearing outer ring can also be called bearing outer ring or bearing jacket, usually fixed on the bearing seat or machine housing, play the role of supporting the rolling body.  The outer ring surface is provided with a groove for rolling steel balls or rollers, known as the outer groove or outer raceway.  

Rolling element  

Rolling element is the core element of rolling bearing, because of its existence, there is rolling friction between relative moving surfaces.  The types of rolling body are ball, cylindrical roller, cone roller, needle and so on.  The rolling body of rolling bearing mainly includes steel ball and roller 2 types.  

The bearing inner ring  

Bearing inner ring can also be a bearing inner ring or bearing inner sleeve, usually fixed on the journal, the inner ring rotates with the shaft, the outer surface of the inner ring for the steel ball or roller rolling groove, called the inner groove or inner raceway.  

Bearing cage  

Bearing cage, also known as bearing retainer, refers to the bearing parts that partially wrap all or part of the rolling body and move accordingly to isolate the rolling body, and usually guide the rolling body and keep it in the bearing.  

The role between inner ring, outer ring and cage and rolling body:  

The inner ring and the shaft are matched with fixed bearings to provide half of the moving track of the rolling body and transfer load;  The outer ring and the bearing seat are matched with fixed bearings to provide the other half of the rolling track and transfer load;  The cage connects all the rolling bodies together to make the rolling bodies bear uniform force;  The rolling body bears the load from the inner ring or outer ring, so that the bearing keeps rotating under the action of load.

The working principle of rolling bearing  

• Generally, the inner ring of the rolling bearing is sheathed on the rotating shaft and rotates together with the rotating shaft, while the outer ring that does not rotate is fixed in the hole of the rolling bearing seat of the casing.  In the annular cavity between the inner ring and the outer ring, there are a plurality of rollers, and the rollers are evenly distributed on the circumference with a cage (also known as a separator cage).  The inner and outer ring contact with the roller ring called the raceway.  Rollers are usually made in the shape of a ball (bead), a cylinder (rod) and a thin and long needle.  According to the different shape of roller, rolling bearings can be divided into ball bearings, rod bearings and needle bearings and so on.
• The inner ring of the rolling bearing rotates with the rotating shaft, and the raceway of the inner ring rotates the roller, so that the roller rotates both on the inner ring raceway and on the outer ring raceway about its axis line, and also with the cage on its axis, as if the earth were rotating simultaneously around the sun.  Various loads on the rotating shaft, such as radial force and axial force, are transmitted from the raceway of the inner ring to the raceway of the outer ring through the roller, and then from the outer ring to the casing.  Because when rolling bearings work, there is always relative movement between the raceway and the roller, but also to withstand a lot of force, in order to avoid wear, the inner and outer rings and rollers need to use special rolling bearing steel to make, otherwise, rolling bearings can not work.
• A rolling bearing, composed of several simple parts, plays a very important role, it can be said that rolling bearings support half of the rotating machinery.  There are only a few rolling bearings which are very important in many complicated machines.  Although the quantity is small, it plays an extremely important role in the normal operation and service life of the whole complex machinery.  It involves a very wide range, can be understood as no bearing, the shaft is a simple iron bar.