What are the types of ball screw?
Classification of Ball Screws By ball circulation method, the Ball Screws are divided into return-pipe type, deflector type and end-cap type. And by preloading method, fixed-point preloading (double-nut method, offset preloading) and constant-pressure preloading are selectable.
How do you calculate ball screw speed?
DN Value. The concept of DN is a simplified way of determining the maximum rotational speed of a ball screw. DN is simply the multiplication of nominal diameter of the ball screw (in mm) times the maximum allowable speed (in rpm).
How much weight can a ball screw hold?
A ball screw drive translates rotational motion to linear motion or vice versa and can apply or withstand high thrust loads – upward of 750,000 lbs static capacity using a Ø6.
Does a ball screw have two circuits?
Multi-start ball screw assemblies typically use the internal channel method of recirculation. These can be designed to have multiple circuits, by incorporating more than one internal recirculation channel in the nut body.
What is the difference between a ground ball screw and a rolled ball screw?
In ground screw threads, the material blanks typically undergo case hardening before the threads are ground onto the blanks. Rolled screw threads undergo a similar case hardening process only after the threads have been rolled due to the fact that case hardened surfaces are too hard to go through the rolling operation.
Can a ball screw be back driven?
Unlike Acme screws, which have enough internal friction to hold their position, the low friction in ball screws tends to let them back drive under load.
How do you preload ball screws?
One way to produce preload in a ball screw assembly is to use a double ball nut, with either a spacer or spring between the two nuts. Double ball nut designs produce preload in one of two ways: through tension between two single nuts, or through an offset in the lead of a single nut.
Can you Backdrive a ball screw?
Lead screws and ball screws have different tendencies to back drive—lead screws typically have a very low chance of back driving, whereas ball screws are more likely to allow the load to fall. This disparity comes down to efficiency.
When would you use a ball screw?
Generally speaking, ball screws are better for applications that require smooth motion, efficiency, accuracy, precision, and prolonged continuous or high-speed movement. Traditional lead screws are more suitable for simple transfer applications for which speed, accuracy, precision, and rigidity are not as critical.
What are the reasons to use a ball screw?
Ball screws are designed to apply or withstand high thrust loads with minimum internal friction. The ball bearings are used to eliminate friction between the nut and the screw and offer a high level of efficiency, load capacity and positioning accuracy.