• EN

# Selection of rolling bearings

Published on：

2022-07-28 16:23

1. Bearing capacity
We mentioned earlier that rolling bearings can be divided into ball bearings and roller bearings. The classification is based on the different shapes of rolling elements.
Generally speaking, under the same overall dimensions, the bearing capacity of roller bearings is 1.5-3 times that of ball bearings, so when there is a large load or impact load, we can give priority to roller bearings.
However, when the diameter is less than or equal to 20mm, the bearing capacity of the two is not much different, and the price of ball bearings is cheaper than roller bearings, so we give priority to ball bearings.

2. The speed cannot exceed the limit speed
Too high speed of rolling bearings will increase the temperature between friction surfaces, resulting in high temperature. In this case, the lubrication of the two metal surfaces fails, and the rolling will cause bonding failure.
Gluing phenomenon: the two surfaces in contact will stick together. Due to relative sliding at this time, the bonded part may be torn, and then scars will be formed on the surface along the sliding direction.
We call the maximum allowable speed of a rolling bearing under certain load and lubrication conditions as the limit speed.
In the design, if the speed of the rotating shaft is known, when selecting the rolling bearing, we should make its limit speed greater than the speed of the shaft, so that the rolling bearing is safe.
The limit speed of rolling bearings can be found in the mechanical design manual.

3. Allowable range of angular deviation
The central line of the inner and outer rings of the bearing will be relatively inclined due to incorrect installation or shaft deformation. The angle of inclination is called angular deviation.
If the angular deviation is too large, it can even affect the normal operation of the shaft. At this time, you can choose self-aligning bearings, such as self-aligning ball bearings or self-aligning roller bearings.
The outer race of self-aligning bearing is a spherical surface centered on the bearing center, so it can be self-aligning.
Angular deviation is not allowed for thrust ball bearings and needle roller bearings.
The thrust ball bearing can only bear axial load, and the action line in the load direction must coincide with the axis.
If there is angular deviation, the thrust ball bearing will be seriously damaged.
The rolling element of needle roller bearing is in line contact with the outer ring, which is most sensitive to axis deflection. It should be avoided to use in the case of axis deflection.

4. Angular contact radial bearings should exist in pairs and cannot exist alone
Here, angular contact radial bearings generally refer to tapered roller bearings and angular contact ball bearings.
When the shaft is in contact with the bearing, the angular contact radial bearing will generate additional axial force due to the existence of contact angle when bearing radial load, so it is generally used in pairs.
There are two ways of installation: front installation and reverse installation.
The front installation means that the narrow edges of the two outer rings are opposite, and the reverse installation means that the wide edges of the two outer rings are opposite.

5. Lubrication mode
The lubricant of rolling bearings can be grease, lubricating oil, or solid lubricant.
Generally, rolling bearings are lubricated with grease.
Grease lubrication is easy to seal and maintain because the grease is not easy to lose, and it can run for a long time after filling the grease at one time.
The advantage of oil lubrication is that it has less friction resistance than grease lubrication and can dissipate heat. It is mainly used for bearings with high speed or high working temperature.

Related News

Bearing retainer, also known as bearing cage, is one of the main parts of the bearing. Its role is to wrap and isolate the rolling body and move with it, and usually also has the role of guiding the rolling body. The cage is subjected to stresses caused by friction, strain and inertia forces, and also to the chemically corrosive effects of lubricants, additives in lubricants or substances due to their aging, organic solvents or coolants. Therefore, the design and material of the cage are extremely important for its performance and the reliability of the bearing.

2021-09-15

Rolling bearings in the process of use due to its own quality and external conditions, its bearing capacity, rotational accuracy and friction reduction performance will change, when the performance index of the bearing is lower than the use of the requirements and can not work properly, there will be machinery and equipment to stop running, the function of damage and other abnormal phenomena. If effective maintenance procedures are taken in bearing mounting and dismounting, lubrication, pollution prevention and personnel training, online inspection and timely troubleshooting, the above failures can be avoided. Bearing mounting and dismounting should pay attention to the use of appropriate tools and methods Bearing mounting is a strict maintenance work, the good or bad mounting, directly affect the accuracy, life and performance of the bearing.

2021-09-15

Of course there is lubricant inside the wheel bearings of a car, but it is a low-fluidity grease (yellow dry oil). Of course the wheel bearings of a car can break down, but when they do, they can simply be replaced with new bearings. Relatively speaking, the rolling bearings used in small non-load machinery are maintenance-free for life, which is different from the sliding bearings that are often changed.

2021-09-15

Rolling bearings show a strong regularity in their use, and repeatability is very good. Normal high-quality bearings (rolling bearings) in the beginning of use, vibration and noise are relatively small, but the spectrum is somewhat scattered, the amplitude are small, may be due to some defects in the manufacturing process, such as surface burrs, etc..

2021-09-15

Rolling bearing is an important mechanical components, a mechanical equipment whether the function can give full play to the bearing smooth can be appropriate, smooth is to ensure the normal operation of the bearing necessary conditions, it is on the progress of bearing bearing bearing capacity and use of life plays an important role. No matter what kind of smooth method is used, smooth in the rolling bearing can play the following kinds of effect.

2021-09-15

Suzhou Dongwu Needle Roller Bearing Co., Ltd. is located in Suzhou Industrial Park, adjacent to Wusong River and airport road in the south, national highway 312 and Shanghai Nanjing Expressway in the north, with superior geographical location and convenient transportation.

2021-09-15