Background: The motorized spindle preload technology is one of the motorized spindle key
technologies, and adjusting the preload according to the working conditions can effectively improve the
dynamic performance of the motorized spindle and enhance the machining accuracy.
Objectives: Review the preload mechanism development, introduce various preload mechanisms, and
show research status in recent years. Then to explore and predict the future development of preload technology
through the analysis of the overall preload mechanism.
Methods: Search for different kinds of patents and literature about spindle preload structure in recent
years. Through structural research and comparison with the traditional preload mechanism, to review the
structure principle of various preload mechanisms at the present stage, then shown the advantages and
disadvantages of each structure.
Result: According to the patents and research of the preload mechanism in recent years, classification
introduced the piezoelectric ceramic preload device, electromagnetic preload device, and hydraulic preload
device, and so on. Introduce their advantages and existing problems in detail, then comprehensively
compare the advantages and disadvantages of various mechanisms in control and mechanism. Finally,
discuss the prospects and development directions of preload technology.
Conclusion: With the further development of technology, high-precision products have higher requirements
for machine tools, such as low latency, low heat generation, high efficiency, and long life. People
use electromagnetic force, air pressure, hydraulic pressure, and other methods, to control the magnitude of
the preload, maintain the performance of the motorized spindle at a high level. Compared with the traditional
quantitative preload, their applicable working conditions are more extensive and accuracy is higher.
However, various new preload methods still have certain shortcomings and need further improvement.