Spindle bearings are key parts for CNC machine tools to achieve fine processing and efficient operation. If you want the CNC machine tools to work stably, in addition to choosing high-quality machine tool spindle bearings, you must also pay attention to the assembly process and correct use methods . Among them, the preload of CNC machine tool spindle bearings is often overlooked. So how to do a good job of bearing preload? This guide will introduce in detail the importance and operation methods of CNC machine tool spindle bearing preload , please read carefully .
CNC machine tool spindle bearing types
According to the processing type and working principle of CNC machine tools , different CNC machine tool spindles use different bearings . The following seven types of bearings are commonly used in the spindle parts of CNC machine tools :
- Angular Contact Ball Bearings
- Tapered Roller Bearings
- Cylindrical Roller Bearings
- Deep Groove Ball Bearings
- Hybrid Bearings
- Hydrostatic Bearings
- Magnetic Bearings
Machine tool spindle bearings
What is the significance of preloading the spindle bearings of CNC machine tools ?
1. Improve work accuracy
CNC machine tool spindle bearing can eliminate its internal clearance, allow the rolling elements to bear a certain preload, provide support force to the rings in all directions, allow the spindle to be correctly positioned, and help improve the bearing rotation accuracy. This is very important in high-precision applications such as machine tool spindles or measuring instruments.
2. Improve bearing stiffness
After the bearing is preloaded, the contact area between the rolling element and the raceway will increase, and the rings in all directions can obtain a certain amount of spring support, which will increase the number of rolling elements bearing the load and improve the overall stiffness of the bearing. When the bearing is subjected to external loads, the bearing deformation is reduced and the ability to resist deformation is further enhanced.
3. Improve bearing service life
the preload operation , the number of rolling elements bearing the load of the bearing is greater, and the load borne by the spindle bearing can be evenly distributed. In this case, the load borne by a single rolling element is significantly reduced, the wear rate of the rolling element is reduced, and the service life of the bearing is increased.
4. Reduce noise and vibration
After pre-tightening, a stable oil film will be formed between the bearing rolling elements and the raceways, which will improve the damping and support dynamic characteristics between the two, help reduce the noise and vibration levels of the machine tool spindle bearings during operation, and improve the overall working performance of the machine tool.
5. Increase load capacity
Preload increases the load-carrying capacity of the bearings. This increase enables the spindle to handle heavier cutting loads without compromising performance, enabling more demanding machining operations.
6. Improve working conditions
For bearings such as angular contact ball bearings, preload can effectively prevent the steel balls from spinning and slipping , and help improve the dynamic performance stability of the bearing under high-speed rotation conditions.
7. Increase the speed
Preloaded bearings can support higher speeds while reducing the risk of damage or failure. This capability is especially important in high-speed CNC machining, where spindle speeds can reach tens of thousands of RPM.
Preloading spindle bearings is essential to optimizing the performance, accuracy, and durability of CNC machine tools. It improves rigidity, accuracy, and bearing life while enabling higher speeds and better thermal stability.
By ensuring that spindle bearings are properly preloaded, manufacturers can achieve better machining results and maintain long-term equipment reliability. So, how do you preload CNC machine spindle bearings ? Read on .
Operating Guide for Preloading CNC Machine Tool Spindle Bearings
1. Pre-adjust the bearing width difference or axial clearance, and then fasten the adjusted combined bearing to the spindle of the CNC machine tool for use.
2. Adjust the size of the machine tool spindle bearing spacer or gasket to apply preload force to the bearing to achieve the preload effect.
3. When adjusting the screw and nut of the axial clearance, measure the starting friction torque while adjusting until the preload is added to the appropriate position. This method is difficult to control the preload force, and the bearing may tilt. It is not recommended if the machine tool spindle has high precision requirements.
4. Use elastic elements such as cylindrical springs and butterfly springs to apply appropriate preload to the bearings. They are generally used in high-speed rotating angular contact bearing pairs.
Conclusion
Preloading CNC machine tool spindle bearings is a critical procedure that requires precision and attention to detail. By following these steps and ensuring the correct preload, you can improve the performance, accuracy and life of your spindle assembly . If you are still confused about this operation , please contact our professional bearing engineers who will provide you with the necessary training or video tutorials .
