Does the Preload of Linear Guide Directly affect the Working Life？

When the load is small and the light linear motion is expected to be obtained without high accuracy, the clearance structure can be used in the linear guide mechanism to allow the slider to move slightly in the direction of thickness, which is called the radial clearance. The gap structure not only reduces the resistance of the linear guide during operation, but also absorbs the slight errors caused by various reasons during assembly.

When the load is applied to the ball bearing in the slider, if there is a gap between the ball bearing and the guide rail and the slider, a certain displacement will first occur between the slider and the guide rail, and then the contact part of the ball bearing and the guide rail and the slider will produce a certain elastic deformation, so as to reduce the movement accuracy of the load. Under the condition of vibration and shock, this effect will be greater. The manufacturer solves this problem by preloading the ball bearing joint with internal stress applied to the linear guide mechanism before it leaves the factory. This not only can eliminate internal stress ball and the space between the guide rail and slide block, but also make the ball with the guide and the slide block contact parts in advance to produce elastic deformation, the external load imposed slide block to be absorbed by the internal stress, buffer, reduces the elastic deformation, thus increasing the stiffness of the linear guide mechanism, namely improve the bearing capacity of the organization. This structure is often called negative gap structure.

In order to meet the needs of different conditions, manufacturers have designed a variety of different preload grades for users to choose. Preload grade codes vary slightly from company to company. It should be noted that when high stiffness is required, excessive preload will cause excessive stress between the ball and the guide rail and the slider, which is also the main factor to shorten the working life of the linear guide mechanism. Therefore, it is very important to choose appropriate preload grade to ensure the normal working life of linear guide mechanism.