Backlash refers to the axial or rotational play between two interconnected machine parts, such as between the spindle and nut of a threaded drive. It is the differential movement that occurs before a force is transmitted in the opposite direction—in other words, the inevitable “play” between the contact surfaces.
Meaning
Backlash affects:
- Positional Accuracy: High backlash leads to inaccuracies during changes in direction.
- Repeatability: Backlash can significantly reduce precision, particularly in CNC machines and robotics.
- Friction Behavior: Backlash can cause short-term shocks and uneven force transmission.
- Service life: Uncontrolled play increases localized stress on flanges or balls and can accelerate wear.
Technical aspects
- Bei Kugelgewindetrieben wird Backlash durch Vorspannung der Mutter minimiert, sodass die Kugeln die Flanken dauerhaft berühren
- Bei Trapez– oder Sägegewinden entsteht das Spiel durch Fertigungstoleranzen und lässt sich nur teilweise durch Vorspannung reduzieren
- Backlash is typically specified in millimeters of axial movement or in degrees of angular displacement.
- Die genaue Einstellung ist abhängig von Lastanforderungen, Steifigkeit und Betriebsbedingungen.
Practical relevance
- In precision machines, backlash must be kept to a minimum to ensure accurate positioning and smooth motion.
- In dynamic applications, excessive backlash can cause vibrations, noise, and inaccuracies.
- Backlash can be effectively reduced through preload, appropriate bearings, and optimized flank profiles.