The main factors which determine the roller load capacity are the tube, shaft and bearing. The load capacity is dictated by the weakest of them:
- Excessive load will distort the tube during roller operation which may result in permanent damage leading to unstable conveying of the product.
- If the load capacity of the shaft is insufficient, it will change the adaptive capacity of the shaft and influence the running performance.
- If the load exceeds the permitted load of the bearing, it will greatly reduce the bearing’s lifespan.
You need to know the following design information:
- The rated load capacity of a single roller is the uniformly distributed load on the roller surface (not point load).
- The method of mounting the shaft to the conveyor frame. For example, an internal threaded shaft has a higher load capacity than a loose mounted shaft such as a spring loaded shaft.
- For each application, you need to consider how flat the product conveying surface is and any partial forces encountered during conveying.
- Steel tube and stainless steel tube have similar mechanical properties with regards to load capacity so are typically considered to have same load capacity.
- Increasing the thickness can strengthen the tube’s impact resistance (not easy to dent), but has little influence on the roller’s load capacity.
- In some modes of conveying, especially in belt conveying, duty plays a decisive role rather than the load. The duty depends on the driving force such as belt maximum tension and chain tension.
Duty: Maximum loading of driven roller.
Load: Roller’s maximum weight capacity.