Deep groove ball bearings are one of the most versatile bearings available. They are also known as Conrad-type bearings or radial bearings. These bearings offer radial load support while handling both radial and axial loads simultaneously. A common question that arises regarding deep groove ball bearings is – do they need preload? Here is a detailed overview of the concept of preload. Along with that, you can figure out whether there is a need to preload deep groove ball bearings.
What is Preload in Bearings?
Preload refers to the initial internal clearance or tension applied on the bearing. This happens during installation and assembly. It basically forces the rolling elements in the bearing to constantly remain in contact with the raceway. Preload can be beneficial for several reasons:
1.It helps remove any internal clearance or ‘play’ in the bearing. This can prevent vibration or noise issues, especially at high speeds. It also makes the system more stable and smooth to run.
2.The loaded zone of contact between the balls/rollers and raceways becomes more defined. This distributes the applied external load over a larger area, minimizing concentrated stresses.
3.Frictional torque gets reduced due to an increase in the number of rolling elements sharing the load in preloaded bearings. This improves efficiency.
Therefore, preload enhances bearing rigidity, load capacity, and overall performance. However, excessive preload should be avoided as it leads to premature wear, higher temperatures, and reduced service life.
Do Deep Groove Ball Bearings Require Preload?
Deep groove ball bearings are designed and manufactured for operation without preload under normal working conditions. Their internal radial clearances permit relative motion between the races to handle misalignment and thermal effects. Hence, applying a preload is often unnecessary.Our 6217 bearings, 6000 Series Bearings have been selling well, click to see the latest news.
Reasons why deep groove ball bearings typically do not use preload are:
1. They can support medium to high radial loads and moderate axial loads without needing extra rigidity from preload. The ball and raceway contact is optimized for load handling capability.
2.They exhibit less sensitivity to loss in preload over time compared to other preloaded bearing types like angular contact or tapered bearings.
3.Since there are no positional tolerances between the ring faces, these bearings can easily accommodate misalignment without impacting operation. Preload may over constrain them.
4.These bearings already run cooler than their preloaded counterparts owing to lower friction. Added preload heat needs to be managed.
5.Preload forces cannot counterbalance external loads trying to separate the rings in one direction, making it unsuitable for single-direction axial loads.
6.Eliminating preload simplifies system design and eases installation by removing the need to set, measure and maintain precise preload values.
When is preload required?
Adding preload is generally not required for standard off-the-shelf deep groove ball bearings going through normal running speeds, temperatures, loads and alignment conditions. Their internal design clearance is adequate for most general applications. However, some factors where preload may be recommended are:
1.In situation dealing with extreme levels of vibration or shock loads
2.High temperature differentials in service cause bearing fit to loosen over time
3.Accuracy-critical applications like high-precision machine tools, instruments, etc. require exceptional motion smoothness.
4.Very high speed systems above the typical capability range of deep groove ball bearings
While deep groove ball bearings are well optimized to perform reliably without extra preloading, their selective usage can maximize stability and precision when operating limits are pushed or application demands are stringent.