How to select a bearing

When selecting a bearing, the bearing structure is generally determined by considering the arrangement of the bearings as a shafting, the difficulty of installation and disassembly, the allowable space and size of the bearing, and the marketability of the bearing.

Secondly, the design life of each machine using the bearing is compared and the various durability limits of the bearing are compared, and the bearing size is determined.

In addition, according to different applications, it is necessary to select bearings that are specially designed for accuracy, clearance, cage structure, grease, etc. However, there is no certain order and rule for the selection of bearings, and the priority should be given to the conditions, performance, and most relevant options required for the bearing, which is particularly practical.

 

Rolling bearings are precision components and their use must be carried out with corresponding care. Precautions for use are as follows:

(1) Keep the bearing and its surroundings clean

Even small dust that is not visible to the eye can have a bad effect on the bearing. Therefore, it is necessary to keep the surroundings clean so that dust does not enter the bearing.

(2) Use with caution and caution

If the bearing is subjected to a strong impact during use, it will cause injuries and indentations, which can become the cause of accidents. In severe cases, cracks and fractures may occur, so it is necessary to be careful.

(3) Use appropriate operating tools

Avoid replacing existing tools with the right ones.

(4) Pay attention to the corrosion of the bearing

When operating bearings, sweat on your hands can be the cause of rust. Be careful to use clean hands, and it's best to wear gloves as much as possible.

Before installation, unpack. General grease lubrication, no cleaning, direct filling grease. Lubricating oil lubrication does not need to be cleaned normally, but bearings for instruments or high-speed bearings should be washed with clean oil to remove the rust inhibitor applied to the bearings. Bearings with rust inhibitors removed are prone to rust, so they should not be left alone. In addition, bearings that have been sealed with grease can be used without cleaning.

The mounting method of the bearing varies according to the bearing structure, fit and conditions, and in general, because the shaft is mostly rotated, the inner ring needs an interference fit. Cylindrical bore bearings, mostly pressed into by press, or mostly by hot fitting method. In the case of taper holes, it can be installed directly on the taper shaft or with a sleeve. When installed in the housing, there is generally a lot of clearance fit, and the outer ring has an interference amount, which is usually pressed in with a press, or there is also a cold shrink fit method for installation after cooling. When dry ice is used as a coolant, the moisture in the air will condense on the surface of the bearing. Therefore, proper rust prevention measures are required.

In order to maintain the original performance of the bearing in good condition for as long as possible, it is necessary to maintain and overhaul it to prevent accidents, ensure the reliability of operation, and improve productivity and economy. Maintenance is best carried out on a regular basis according to the operating conditions of the machine. This includes monitoring of operating conditions, replenishment or replacement of lubricants, and periodic disassembly inspections. As a maintenance item during operation, there are bearing rotation sounds, vibrations, temperatures, lubricant conditions, and so on.