The linear guide pairs are classified according to the contact tooth type of the ball on the linear guide and the slider, mainly the Goethe type .
Gothic Type is also known as the two-row type and the round-arc type is also known as the four-row type. Generally, the selection of linear guide pairs must be selected according to the conditions of use, load capacity and life expectancy. However, due to the large life dispersion of linear guides, in order to facilitate the selection of linear guides, the following important concepts must be clear.
1. The accuracy level of linear guide rail: The accuracy of general linear guide rail is divided into five kinds: ordinary, advanced, precision, ultra-precision and ultra-precision.
There are three main detection indicators in one strand, one is the parallelism of the slider C facing the slide rail -A surface, and the third is the slider D facing the slide rail
The parallelism of the B side, the third is the walking parallelism, the so-called walking parallelism refers to the parallel error between the guide rail and the datum plane of the slider when the linear guide rail is fixed on the datum plane of the base seat, so that the slider walks along the stroke.
2. Pre-pressure of linear guide rail: The so-called pre-pressure is to give the steel ball load force in advance, using the negative direction between the steel ball and the bead
The gap is precompressed, which can improve the rigidity of the linear guide and eliminate the gap.
According to the size of the pre-pressure can be divided into different pre-pressure grades. The pre-pressure varies from a gap to. The C value is the dynamic rated load. During the selection process, it can be re-selected and set at any time according to the calculation result. When calculating the maximum load of the slide block, it should be confirmed that the static safety factor of the selected linear guide should exceed the value listed in the recommended table.
If the selected linear guide pair is not rigid enough, the pre-pressure can be increased, the selection size can be increased or the number of sliding blocks can be increased to improve the rigidity. Static safety factor is defined as the ratio of static rated load to working load. It is worth mentioning that the linear guide pair of the two columns of the Goethe structure can withstand the force and the force is short, and it is more in the application of red load or medium load, and it is larger in the four-way force load. The linear guide with four-row circular structure has the ability to absorb the errors of the assembly surface in the application of heavy load or heavy load. However, if there is an impact load, it is appropriate to choose the linear guide of the Goethe-type structure
A rail pair.
- Rated life of linear guide rail: The so-called rated life refers to a batch of the same product, under the same conditions and rated load, 90% of the tube surface stripping phenomenon and reach the operating distance. The linear guide pair uses the steel ball as the rated life of the rolling element, which is 50km under the basic dynamic rated load.
4. The 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 of the ball and raceway surface is just one millionth of the diameter of the ball at the contact surface under the condition of equal load direction and size. Due to the higher and higher precision requirements in machining, it is important for processing machinery
The precision classification of component linear guides is becoming more and more fine.
5. Linear guide basic dynamic rated load (C: The so-called basic dynamic rated load refers to a batch of linear guides of the same specifications
Under the fast state of equal load direction and size, after running 50km/ km, 90% of the straight guide rail does not produce the highest load when the raceway surface is damaged (peeling or pitting).
Post time: Sep-13-2023