Ball Screw Assembly Lubrication

When you purchase a ball screw or a machine that includes a ball screw assembly you should understand the correct care of this tool. A ball screw holds a lot of different parts, e.g the ball screw nut, the ball bearings, the screw and the recirculation apparatus. Every item mentioned must be cared for appropriately, in order to increase the functionality of your ball screw. Probably the principal part of ball screw maintenance is appropriate lubricant. Applying sufficient lubricant ensures that the ball bearings and other components can move more freely together. This reduces friction and wear, ensuring your ball screw assembly has improved efficiency and maximising its lifetime. It is understood that ball screws that are used minus lubrication can experience a lifespan reduction of up to eighty-five percent. Another bonus point to making use of lubricants makes the metallic parts waterproof, shielding against corrosion. The two most common lubricants added to ball screws and mainly in the ball screw nut region are oil and grease. It is important to note that it is ill advised to utilise grease in a ball screw assembly that rotates very quickly, or with one that is used at low temperatures. A further point to note is that it is better that you never use a grease that contains minute solid components, and it is also best not to use graphite grease. Anything that has solid particles in it may jam the ball screw assembly, stopping the ball bearings from rolling easily.

It is crucial that the ball screw assembly is frequently cleaned. Any particles or dirt can be detrimental to the mechanics of the ball screw. You should also refrain from using a lot of oil. Excessive use of oil can congest the ball screw nut, blocking the ball bearings and clogging the threads.

Ball Screw Assemblies

It is immediately apparent that a ball screw cannot be described as a simple tool. Actually there are a lot of pieces with the whole thing being called a ball screw assembly. The central parts of a ball screw assembly are the pieces called the nut and the screw. The nut moves linearly on the screw when either of these two parts are rotating. Most commonly the circular movement of the screw causes the nut to move sidewards, but the action can also be reversed which means the ball screw is being back-driven. Ball screw assemblies aren’t really exceptionally intricate. The nut contains ball bearings, and these circulate through the ball nut. The appearance of the screw is typical, in that it has helical threads cut into it. Within the nut similar threads have been created which create tracks for the ball bearings to follow. Once the screw revolves this sets the ball bearings into motion, which is the cause of the nut’s movement on the screw. The ball screw assembly has a deflector as a last component that keeps the ball bearings in circulation inside the nut. Once the ball moves to the end of the nut the deflector reverses its motion, sending it back to the top of the nut. A circuit is therefore formed, or a cycle of ball bearings inside the nut casing. This is the fundamental mechanism of the ball screw assembly.

It is possible to work out the life and load of ball screw assemblies by counting the threads on the screw along with the amount of threads inside the nut. For every instance that equates to a complete movement of the nut along the screw, every screw thread has had each ball bearing travel along it once. As well as this, the threads in the barrel of the nut may have had the balls pass through them many times over which of course is dependent on the relative screw length. It can be seen that the proportional difference between the nut thread count and the screw thread count will reveal the amount of extra work done on the ball nut surface which should help you to work out how long the ball nut will last when compared with the life of the ball screw. Some ball screw assemblies can be expected to have a greater durability, as can be calculated using the relative thread counts.