What Is The Function of Steel Ball in Ball Screw Nut?
Publish Time: 2025-09-10 Origin: Site
The steel ball in a ball screw nut is its most critical component, which distinguishes it from lead screws. The core function of the steel ball is to transform sliding friction between the screw and nut into rolling friction. Here are the specific functions of the steel balls:
1. Reduce Friction and Improve Efficiency
This is the most fundamental function. The trapezoidal screw has a high coefficient of friction, most of the energy is wasted in overcoming friction and heat. The ball screw through the rolling of steel balls, the coefficient of friction is very low.
Character | Lead screw (sliding friction) | Ball screw (rolling friction) |
Transmission efficiency | Lower (typically 20% -40%) | High (typically> 90%) |
Type of friction | Sliding friction | rolling friction |
Energy loss | Most of the heat is converted into heat loss | Low, most of the energy is used for output |
More energy efficient: It requires less torque to drive it. The motor consumes less power and can be selected for a smaller power motor.
2. Enhancing Rigidity and Precision
Through pre-tightening force adjustment, the axial clearance between the screw rod and nut can be reduced, improving system rigidity and minimizing displacement errors. This enables high-precision positioning and micro-feed control, making it ideal for applications requiring extreme precision (such as CNC machine tools and precision measurement instruments). The rolling raceways between the screw rod and nut contain countless precision-engineered steel balls that distribute loads through multi-point contact, significantly increasing the effective load-bearing area. Consequently, trapezoidal screws typically demonstrate superior rigidity compared to their counterparts.
3. Extended Service Life
The wear of lead screws occurs through direct scraping of metal surfaces, leading to gradual loss of precision and eventual failure. In contrast, ball screws utilize rolling friction, resulting in minimal wear. With proper lubrication and dust protection, their service life typically far exceeds that of lead screws. High-quality ball screws can achieve millions or even tens of millions of cycles without failure.
4. Summary
The steel balls in ball screws serve three critical functions:
1) Converter: Transforming harmful sliding friction into beneficial rolling friction.
2) Power transmission medium: Delivering precise and efficient force and motion transfer.
3) Load-bearing partner: Jointly supporting heavy loads through rolling contact.
These balls, combined with their sophisticated circulation design, make ball screws indispensable components in modern industrial equipment requiring high precision, efficiency, and speed – such as CNC machine tools and industrial robots.