Estimation of Ball Screw Life and Influencing Factors

Ball screws are essential components in mechanical transmission, and their lifespan directly affects the performance and reliability of equipment. 

Definition of Ball Screw Lifespan

The lifespan of a ball screw refers to the total number of rotations, time, or distance at which the balls or the rolling surfaces of the ball screws begin to show signs of fatigue and flaking under alternating stress.

According to industry standards, the expected lifespans for different types of equipment are as follows:

Machine tools: 20,000 hours

Automatic control devices: 15,000 hours

Industrial machinery: 10,000 hours

Measuring devices: 15,000 hours

Estimation of High-Precision Ball Screw Lifespan

The lifespan of high-Precision Ball Screws is typically estimated using the L10 lifespan. The L10 lifespan indicates the expected lifespan that 90% of the ball screws can achieve under the same operating conditions. For example, if a certain ball screw has an L10 lifespan of 5,000 hours, then 90% of the ball screws can operate normally for up to that time.

According to ISO 281 standards, the calculation formula for the rated lifespan of a ball screw is as follows:

Lh=(PC​)³×10^6÷(60×n)

Lh: rated lifespan (in hours)
C: basic dynamic load (in N)

P: equivalent dynamic load (in N)

n: rotational speed (in r/min)

Key Factors Affecting Ball Screw Lifespan

• Material and Processing Technology

Materials with good fatigue resistance and wear resistance should be selected, and precision in the manufacturing process should be ensured to minimize errors. HOJAMA ball screws typically use high-quality bearing steel and stainless steel, and materials can be adjusted based on customer needs.

• Operating Environment and Conditions

Environmental factors such as temperature, humidity, corrosive gases, as well as load, speed, and vibration conditions, all influence the lifespan of ball screws. Therefore, it is essential to consider the adaptability to different working environments during the design phase.

• Lubrication and Maintenance

Proper lubrication and regular maintenance are critical for extending the lifespan of ball screws. Adequate lubrication can reduce friction and wear, maintaining the cleanliness and stability of the ball screw device. Regular replacement of lubricants and removal of dust and impurities are vital maintenance tasks.

• Installation and Maintenance

Correct installation and regular maintenance are key to ensuring the normal operation of ball screws. Installation should follow the manual guidelines to avoid uneven force or misalignment, and regular inspections and repairs should be conducted to timely replace worn components in ball screws.

Estimating the lifespan of high-precision ball screws is a comprehensive process that requires consideration of materials, technology, environment, lubrication, and maintenance.