Scientific Selection Guide for Roller Screw Support Accuracy Levels
At present, the common precision level of screw support seat on the market is mainly divided into C3, C5, C7 three levels, each level has unique performance characteristics and application scenarios. From the perspective of bearing configuration, the fixed end usually adopts diagonal ball bearings with a contact angle of 30° or 40°, while the support end uses 6 series deep clearance ball bearings, but there are differences in bearing combinations and pre-pressure settings among different precision grades.
The high precision class C3 is represented by a fixed-end bearing system with P5 bearings in a DF combination. Applying moderate preload between the two bearings can eliminate the running clearance of the screw and avoid excessive backlash of the machine. The combination of the screw and the bearing housing can precisely maintain the accuracy of the bearing housing datum surface and ensure the high rotational accuracy of the screw, which is suitable for high-precision CNC machine tools, semiconductor equipment and other scenarios that require strict positioning accuracy.
The C5 class fixed end is also fitted with P5 class bearings and is also of the DF combination type, although it has a relatively large preload between the bearings. Although this larger preload helps to avoid screw positions, it may lead to large machine backlash values. This accuracy class is suitable for automated machines that require high accuracy but are slightly lower than the C3 class, such as general CNC machine tools and automated testing equipment, to ensure a certain level of machining accuracy while balancing cost and performance.
The C7 grade, as the basic precision grade, is equipped with P0 grade bearings with no overpressure adjustment between the two bearings. This results in relatively large displacements and weak precision stability when the screw is stalled. Therefore, C7 grade is more suitable for general mechanical transmission scenarios that do not require high precision, such as some common automated production lines, logistics handling equipment, etc., which can effectively control the cost of the equipment under the premise of meeting the basic functional requirements.
In addition, there is a slight difference in the datum from the table to the bearing center for different precision screw supports. This difference will have an impact on the installation and commissioning of the entire drive system and the final operating accuracy. In the actual selection process, in addition to considering the precision requirements of the equipment, but also need to combine the operating speed of the equipment, load size, working environment and other factors to make a comprehensive judgment.
Mastering the characteristics and selection points of the accuracy level of the roller screw support base is the key to ensure the efficient and stable operation of mechanical equipment. I hope that through the above explanation, we can provide a strong reference for you in the actual selection process. If there are other questions, welcome to communicate at any time!
