[Introduction] The Basic Concept of Rolling Bearings

        Basic structure of rolling bearing

Rolling bearings are widely used in all kinds of machinery in the important basic components, the International Organization for Standardization under the definition of rolling bearings is: in the bearing load and relative movement of parts between rolling (not sliding) movement, it includes raceway parts and with or without isolation or guide parts of the rolling body group. Rolling bearings are generally composed of four basic geometric parts: inner ring, outer ring, rolling body and cage (commonly known as "four large parts", most of the actual working occasions must also have lubrication), as shown in Figure 1-1. In thrust bearings, the ring matched with the shaft is called the shaft ring, and the ring matched with the bearing seat or the mechanical component housing is called the seat ring. See Figure 1-2. The inner ring is usually mounted on the shaft and rotates with the shaft. The outer ring is usually installed in the bearing seat or in the housing of the mechanical part to play a supporting role. However, in some applications, there are also outer ring rotation, the inner ring is fixed or the inner and outer rings are rotated; There are also more components; There is also no cage, no inner ring, no outer ring, etc.

     The surface on the ring for the rolling body is called the raceway, and the raceway of the ball bearing is also called the channel. The rolling body rolls between the inner ring and the outer ring raceway, and the rolling body structure includes ball, cylindrical roller, needle roller, conical roller and spherical roller, etc., as shown in Figure 1-3. The size and number of rolling elements directly affect the bearing capacity.

      The function of the cage is to separate a group of rolling elements in the bearing equidistant, keep the rolling element separately or form a component with the inner ring or the outer ring, guide the rolling element to move on the correct track, improve the load distribution and lubrication performance of the bearing inside the bearing, compared with the full loaded ball or roller bearing without the cage, one of the differences is that the friction resistance of the bearing with the cage is small. Suitable for high-speed rotation. In the bearing industry, it is customary to use "01" to indicate the outer ring, "02" to indicate the rolling body, "46" to indicate the solid cage guided by the rolling body, and "07" to indicate the stamping cage. In order to adapt to some use requirements, some bearings will increase or reduce some parts, such as no inner ring or no outer ring, neither inner ring nor outer ring (inner ring and outer ring are replaced by matching host parts (shaft or frame)); No cage; Or with dust-proof cover, sealing ring and installation adjustment of the tight sleeve.

Characteristics of rolling bearings

Rolling bearings have a variety of structural types, each type of bearing has its own characteristics, but its common characteristics are:

(1) The starting friction is small, and the difference between the starting friction and the dynamic friction is also small.

(2) Most bearing dimensions have been internationally standardized, with interchangeability, suitable for mass production.

(3) Less wear than ordinary plain bearings, can maintain mechanical accuracy for a long time.

(4) Easy lubrication, less lubricant consumption, low maintenance costs.

(5) can be more convenient to use under high or low temperature conditions.

(6) The surrounding parts matched with bearings have simple structure and are easy to check and maintain.

(7) The rigidity of the bearing can be improved by applying preload.

(8) Except for a few bearings (such as thrust bearings), general bearings can bear both radial and axial loads.