What are the basic requirements to understand when selecting linear bearings

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As a linear motion system, linear bearings structurally consist of an outer ring, a retainer, a ball, and two retaining rings. Through assembly technology, the ball is positioned in the retainer and fixed in the outer ring by the retaining ring. The ball contacts the outer ring of the bearing, achieving high sensitivity and precision in smooth linear motion.

The outer ring of a linear bearing is heat treated to maintain sufficient hardness, ensuring the expected service life of the bearing and achieving the durability required by the user. Retainers are generally made of steel or synthetic resin. Relatively speaking, steel retainers have higher stiffness. Synthetic resin has lower operating noise. Users can choose the appropriate type of linear bearing based on its usage environment.

When selecting, four aspects can be referred to for comparison.

1. Structural type

Generally available linear bearings are classified into standard, flange, extended, clearance adjustment, and open type. There are also some segmented styles that need to be fully considered in the specific selection, such as flange type, including round flange type, flange type, elliptical flange type, guided round flange type, extended round flange type, etc. We can select from them according to the application requirements that need to be met.

2. Performance indicators

The main considerations are high precision and high stiffness. Based on metric dimensions, the outer diameter tolerance of the straight axis used is generally h7 or g6, while based on imperial dimensions, the outer diameter tolerance used is generally g6. In addition, linear bearings use steel outer rings, combined with industrial strength resin retainers, to ensure rigidity.

3. Assembly matching

Easy to assemble, used as a sliding component in industrial machinery such as precision machine tools, textile machinery, food packaging, printing machinery, etc. As a standard linear bearing, it can load from different directions, and precision control can be achieved through the shaft alone. It is also easy to machine the installation surface.

4. Maintenance replacement

With standardized dimensions and strict precision control, it is easy for models to be interchangeable without affecting performance, making maintenance and replacement caused by wear or damage simpler and more accurate.

Starting from the above four aspects, the selection of linear bearings is already clear in mind.

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