Five Small Knowledge Points of Linear Guideway

Linear guides have been widely used in various fields, and many people feel that they are very familiar with linear guides, but do they really understand them? Do you know the five essential knowledge points for linear guides? Today, Renee's editor will talk to you about:

1. Linear guide rail and its pre pressure: Pre pressure is a pre loading force applied to the steel balls, using the negative gap between the steel balls and the ball path to provide pre pressure, which can improve the rigidity of the linear guide rail and eliminate the gap. According to the magnitude of the preload, it can be divided into different levels of preloading. The pre pressure ranges from clearance to 0.13C. The C value is the dynamic rated load. During the selection process, you can return to the previous steps at any time based on the calculation results for re selection and setting. When calculating the maximum load of the slider, it is necessary to confirm that the static safety factor of the selected linear guide rail should exceed the values listed in the recommended table. If the selected linear guide rail has insufficient rigidity, the preload can be increased, the selected size can be increased, or the number of sliders can be increased to improve rigidity. The static safety factor is defined as the ratio of the static rated load to the working load. It is worth mentioning that the two column Goethe style linear guide rail pairs can withstand forces and moments in various directions, and are more commonly used in light or medium load applications, especially when the lateral force load is large. The linear guide rail with a four column circular arc structure is more commonly used in heavy or overweight load applications, and the circular arc type has the ability to absorb assembly surface errors. But if there is an impact load, it is advisable to choose a Goethe type linear guide rail pair.

2. Rated lifespan of linear guides: The so-called rated lifespan refers to the operating distance achieved by a batch of identical products under the same conditions and rated load, with 90% of them not experiencing surface peeling phenomenon. The rated life of the linear guide rail pair using steel balls as rolling elements is 50km under basic dynamic rated load.

3. Basic dynamic rated load (C) of linear guide rails: The so-called basic dynamic rated load refers to the high load of a batch of linear guide rail pairs of the same specifications. After running for 50km in the same direction and size of load, 90% of the linear guide rails do not experience fatigue damage (peeling or pitting) on their raceway surface.

4. The accuracy level of linear guides: Generally, the accuracy of linear guide pairs is divided into five types: ordinary level, advanced level, precision level, ultra precision level, and ultra high precision level. There are generally three main detection indicators: first, the parallelism between slider C and slide rail A, second, the parallelism between slider D and slide rail B, and third, the walking parallelism. The so-called walking parallelism refers to the parallelism error between the guide rail and the slide rail reference plane when the linear guide rail is fixed on the reference seat plane and the slide rail moves along the stroke.

5. Basic static rated load (Co) of linear guide rail: The so-called basic static rated load refers to the static load when the total permanent deformation between the steel ball and the raceway surface is exactly one thousandth of the diameter of the steel ball at the contact surface subjected to high stress, under the condition of equal load direction and magnitude. Due to the increasingly high precision requirements in mechanical processing, the precision level classification of important component linear guides in machining machinery is becoming increasingly refined.