Linear bearings - this is a generalized term for a number of mechanical components necessary for the smooth movement of a carriage or sleeve along a rail or shaft. These mechanisms may have a simple or complex device.
It should be remembered that in different sources linear bearings can be called differently. The most common names are:
- Rail guides.
- Bushings (ball) linear displacement.
- Linear motion bearings.
Today, a huge number of various modifications and series of linear displacement bushings has been invented and introduced to satisfy the various needs of many industrial sectors. Every year, with the growing number of state-of-the-art equipment in the industry, repairmen and mechanics need more and more products called “linear bearings”.
Unlike conventional mechanisms that move rotationally, rail guides make translational movements.
That is what determines their device.
- Moving part. These parts can be represented by needle or ball separators, rails, bushings of various modifications, carriages.
- The part along which the movement takes place. This can be a regular or helical shaft, rail, rolling support, etc.
Linear bearings are devices of various configurations and sizes, but all of them are needed in order to bear the load, providing a fixed and thorough linear movement. Such mechanisms include devices with cross rollers and rolling bearings on rollers.
More rare members of the family are hydrostatic and magnetic linear bearings. However, it is precisely such models that are used where particularly accurate or absolutely silent operation is needed.
The most common modifications are linear plain bearings, the same guides, ball bushings.
The "representative" of the latter type can move on a round shaft. In this case, it will consist of a cylinder in which balls move along special tracks in a confined space. Rotational movement of the balls will provide free movement of the sleeve for smooth operation of the entire mechanism.
The carriage can move along the rail. In this case, its movement will be ensured by independent chains of balls of the rolling block. They roll inside a groove specially cut in the rail, pushing each other.
A device of this kind will have a much lower friction force than a mechanism with a sleeve. Its compulsory oil supply and special seals will further reduce its ability to prevent foreign impurities and contaminants from entering the mechanism.
What to consider when choosing linear bearings?
- Loads and expected life.
- The speed of the necessary process.
- Rigidity.
- The accuracy of the final result.
- Design features of the equipment.
- Restrictions on operation or installation.