Thermal stress refers to the strain placed on a component or system by temperature changes and heat generation. In screw drives, particularly ball screws and trapezoidal screws, it is mainly caused by friction, environmental conditions and operating time, and affects accuracy, service life and operational reliability.
Thermal stress leads to:
- Thermal expansion of the spindle, nut and bearings
- Change in preload and funktion
- Path and positioning deviations
- Reduced lubricating effect
- Accelerated wear
Causes
- Friction in the screw drive (balls, thread flanks, seals)
- High speeds and loads
- Long operating time
- Inadequate lubrication
- External heat sources or high ambient temperatures
Technical implications
- Changes in the length of the spindle affect the actual travel distance
- Increase in friction torque due to a change in the viscosity of the lubricant
- Reduced service life if permissible temperatures are exceeded