The quality of the bearing and the choice of clearance

Writer: Eric Bearing Limited

 When customer do not know how to choose suitable bearings for their machine , ERIC BEARING LTD can help you , supply different brand in widely size . Usually , there are 8 points to teach you how to make right choice . 

1. Selection of bearing model

The bearing model is generally selected by the user's technical personnel according to the service conditions and load bearing of the supporting products. The business personnel mainly understand whether the actual load of the user is consistent with the selected bearing. If the bearing does not meet the requirements for use, the customer should be advised to change the model as soon as possible, but unless there is a special product in the selection of the model, there will generally be no problems.

2. The choice of bearing clearance

When purchasing a bearing, users generally only inform about the model and grade, and rarely require the clearance of the bearing. The business person must ask about the bearing’s use conditions, the bearing’s speed, temperature, and tolerances, which are directly related to the bearing. Choice of clearance. Generally, motors with speeds below 3500 rpm mostly use CM clearance. For example, high-temperature and high-speed motors require relatively large clearance. After assembly, the bearing clearance will be reduced due to the expansion of the inner hole and the shrinking of the outer circle. The reduction of the clearance = interference × 60% (except for the bearing chamber is aluminum). For example, the clearance before assembly of the bearing is 0.01mm, and the interference during assembly is 0.01mm, then the clearance after assembly of the bearing is 0.004mm. In theory, the noise and life of the bearing reach the best state when there is zero clearance, but in actual operation, considering the temperature rise and other issues, the clearance of the bearing after assembly is preferably 0.002mm-0.004mm.

3. The choice of grease

The choice of grease is generally based on the bearing speed, temperature resistance, noise requirements and starting torque, etc., and business personnel are required to have a good understanding of the performance of various greases.

4. The choice of bearing seal type

Bearing lubrication can be divided into oil lubrication and grease lubrication. Oil-lubricated bearings are generally selected form bearings, and grease-lubricated bearings are generally sealed with dust caps or rubber seals. The dust cover is suitable for high temperature or good use environment, and the seals are in contact.

5. Bearing quality identification

Whether there are turbid oil stains on the surface, because the current domestic anti-rust technology is not very popular, it is easy to leave thick oil stains when the bearing body is rust-proofed, which is very sticky when held in the hand, while the foreign original There are almost no traces of anti-rust oil on the imported bearings, but a very careful expert said that the imported bearings smelled a kind of smell, it must be the anti-rust oil, but they can't see it. This should be paid special attention to when buying imported bearings.

6. Whether the steel stamp is clear

Brand words, labels, etc. will be printed on the bearing body. The fonts are very small, but most of the products produced by the factory use steel stamping technology, and they are pressed before heat treatment. Therefore, although the fonts are small, they are deeply concave and very clear. The fonts of counterfeit products are relatively fuzzy. Due to the rough printing technology, the fonts float on the surface, and some of them can even be easily erased by hand .   SKF 21313 E/C3 bearings online , pls click here : 

7. Is the outer packaging clear

Under normal circumstances, its own dedicated designers to design the external packaging, and arrange for the production of factories that pass the production conditions, so the packaging is very clear and unambiguous from lines to color blocks. (Some imported bearing brands also have unique designs on their accessories packaging to protect their intellectual property rights).

8. Is there any noise  

Hold the inner sleeve of the bearing with your left hand, turn the sleeve with your right hand, and listen for noise. Due to the backward production conditions of most counterfeit products and the completely hand-made workshop operation, it is inevitable that impurities such as sand will be mixed in the production process, which is hidden in the bearing body, so it will make noise when rotating. This is the biggest difference from a genuine brand that strictly enforces production standards and uses machines to operate.