What are the basic components of a rolling bearing? A rolling bearing consists of four basic parts: inner ring, outer ring, rolling elements and cage. As the core component of rolling bearings, rolling elements convert sliding friction between relatively moving surfaces into rolling friction.

What are the common types of rolling elements? Rolling elements include balls, cylindrical rollers, needle rollers, tapered rollers, spherical rollers and asymmetric spherical rollers.

What are the common types of rolling bearings? Self-aligning ball bearings, spherical roller bearings, thrust spherical roller bearings, tapered roller bearings, steep-angle tapered roller bearings, thrust ball bearings, double-direction thrust ball bearings, deep groove ball bearings, angular contact ball bearings, cylindrical roller bearings without outer ring ribs, cylindrical roller bearings without inner ring ribs, cylindrical roller bearings with single inner ring rib, needle roller bearings, set-screw spherical ball bearings, etc.

What main factors shall be considered when selecting the type of rolling bearing?

What is bearing life? Bearing life refers to the number of revolutions of one ring relative to the other ring before fatigue cracks first expand in the material of a ring or rolling element of an individual bearing. Due to differences in manufacturing precision and material homogeneity, even bearings made of identical materials, with the same dimensions and from the same production batch will have vastly different service lives under identical operating conditions.

What are the main failure modes of rolling bearings? The main failure modes include pitting, plastic deformation, abrasive wear, adhesive wear, corrosion and bearing burning.

What is the basic rating life of a bearing? For a group of identical bearings, the number of revolutions (in millions of revolutions) or operating hours before 10% of the bearings suffer pitting failure and 90% remain intact is defined as the basic rating life, denoted as \(L_{10}\).

What is the basic dynamic load rating of a bearing? The load that a bearing can withstand when its basic rating life reaches exactly one million revolutions is called the basic dynamic load rating, denoted by C. For radial bearings, it refers to pure radial load, marked as \(C_r\); for thrust bearings, it refers to pure axial load, marked as \(C_a\).

What is the equivalent dynamic load of a bearing? When a rolling bearing is subjected to combined radial and axial loads simultaneously, the actual load must be converted into an equivalent dynamic load consistent with the load conditions used to determine the basic dynamic load rating for comparative life calculation under uniform conditions. The equivalent dynamic load is represented by P.

Why is static load calculation required for rolling bearings? Static load refers to the load acting on a bearing when the relative rotational speed between bearing rings is zero or extremely low. Static load calculation is required to limit excessive contact stress and permanent deformation of rolling bearings under static loading.

What is preloading of rolling bearings? Why do rolling bearings require preloading? Preloading means generating and maintaining an axial force inside the bearing during installation to eliminate axial internal clearance and create initial deformation at the contact surfaces between rolling elements and inner/outer rings. Preloading can improve the rotational accuracy of bearings, increase the rigidity of bearing assemblies and reduce shaft vibration during machine operation, so rolling bearings are often applied with preload.

Why do rolling bearings need lubrication? What are the common lubrication methods? Lubrication is vital for rolling bearings. Lubricants inside bearings can not only reduce frictional resistance, but also dissipate heat, lower contact stress, absorb vibration and prevent corrosion. There are two common lubrication methods for bearings: oil lubrication and grease lubrication. In addition, solid lubricants are also adopted in some applications.

What are the common lubrication methods when oil lubrication is used for rolling bearings? Oil bath lubrication, drip lubrication, splash lubrication, jet lubrication, oil mist lubrication, etc.

What is the normal grease filling volume for grease-lubricated rolling bearings? Generally, the filling volume of grease accounts for 1/3 ~ 2/3 of the internal space of rolling bearings.

What are the common sealing devices for rolling bearings? Bearing sealing devices are designed to prevent dust, water, acid gas and other contaminants from entering the bearing and avoid lubricant leakage. Sealing devices are divided into two main categories: contact seals and non-contact seals.