Linear Bearings

When an object is required to be moved in a straight line along a straight line, linear bearings are used to achieve this motion with relative ease. This is especially required to be done with high precision in a manufacturing unit or an industrial setting. Here, the requirement is usually such that the machine or the equipment needs to be transferred in one direction only, with a to and fro motion, and back to its original position. Usually this is a repetitive motion, and it requires an ease of doing this quickly, and due to the uni-direction motion, the function of these bearings are very simple. The function of the bearing would be to provide a sliding or a rolling contact between the machine or equipment, and the races on which it has to be moved and provide an easy motion among the parts. Applications involving shorter length of travel and higher accuracy with some amount of noise and vibration find high use of linear bearings.

A linear bearing provides a sliding motion using balls, slides, bushes, rails, and lubricant. Linear bearings come in various sizes and strengths suited to different requirements of the industry.

Large automated systems such as positioning tables and robotic assembly lines finds a high use of various types of linear bearings. Linear ball slides are one such type, which are very compact, and have a short stroke and a small form factor. Such type of linear bearings can stroke up to one-third of the slide length. If the requirement is for a higher load capacity, crossed roller bearings would be suited in such situation as it can take more loads due to the presence of a contact line between every roller and the raceway.

For general uses of linear bearings, such as workstations and drawer glides, a plastic or low grade metal is usually used, as the stress requirement of the bearing is really low. Linear guide is the term used for linear bearings that have similar requirements in an industrial set-up such as motion control system. Different types of linear bearings are required in various general uses such as precision dispensing, optic alignment, vision inspection, disk certification, automated production equipments, water testing and handling, precision gauging, etc.

There are certain types of linear bearings that can also rotate along with sliding. These are especially useful shafts that move axially as well as rotate. Such special requirements are found in certain industries like printing industry, textile industry, leather processing units etc. These are special type of linear bearings and not generally employed when only linear motion is required.

The main advantage with linear bearings is the relative ease with which it can be installed, and at a low cost. But standardization of products is rarely found due to the presence of number of manufacturers. For this reason, special care needs to be taken regarding the bearings, length, width, diameter, and also the load capacity required for specific application and condition here it is going to be used. Materials such as plastic, bronze or stainless steel are usually used for manufacturing linear bearings. A linear bearing maybe self-lubricating and cleaning, still some bearings may require regular cleaning and lubrication to increase the longevity of such bearings.