Ball screw nut stops / pitch / PUA90 (BSTS15)

Question:

How do you mount a ball screw drive?

Answer:

A ball screw should be stored with a fixed bearing and a floating bearing. The fixed bearing should ideally be installed on the engine side or the drive side. Fixed bearing housings come already equipped with angular contact ball bearings to absorb axial forces. This combination makes ball screws an ideal candidate for positioning. However, a preloaded threaded drive should be selected for very high precision as it has very little axial play.

Question:

Why should a fixed and floating bearing be used?

Answer:

A fixed bearing housing is often used on the drive side. The floating bearing with housing, on the other hand, allows a small axial deviation and thus compensates for a change in length or a length tolerance. This prevents compression and bending of the ball screw and an imbalance through the length compensation. This may already occur by heating the spindle or application. Fixed and floating bearings are recommended in many rotary applications.

Question:

How does a ball screw work?

Answer:

A ball screw works similarly to a profile rail guide . In the nut of the ball screw, balls are in a closed ball circulation, which are guided to the spindle by the circular alignment. Thus, an unlimited stroke is theoretically possible, which, however, is limited by the length of the spindle. It is important to ensure that the nut of the ball screw is not removed from the spindle, because the balls can fall out as a result.

Question:

Why does the spindle oscillate in a ball screw drive?

Answer:

One possible cause for this could be that the ball screw is exposed to excessively high rotational speeds. The permissible rotational speed should not be higher than 80% of the critical speed. Here, attention should be paid not only to the visibly rotating components, but also to the rotational speed of the balls. Further information can be found in the ball screw driver selection as a PDF. Another possibility for the spindle to oscillate could be a compression of the spindle. Therefore, it is important to install a ball screw with a fixed bearing and a floating bearing so that these stresses can be compensated through a floating bearing. MISUMI offers this as ready-to-install bearing housings.

Question:

Is the ball screw nut removable?

Answer:

The ball screw nut or ball wrap nut should not be removed from the lead screw. There is a risk that the balls will fall out of the nut. This also means that the nut should not be extended over the threaded surface of the spindle. To remove the nut, you can work carefully with a transition shaft with the appropriate core diameter. However, MISUMI also offers an option [TAS] that provides a transition shaft with the ball screw drive. If a ball screw with reverse ball screw is required, the option [RLC] can be supplied with the ball screw nut installed in reverse.

Question:

Can you replace just the ball screw nut?

Answer:

A ball screw drive should always be replaced as one unit. If damage or wear has already occurred on the spindle, the accuracy of the ball screw drive can no longer be guaranteed. Therefore, it is always recommended replacing spindle and nut together. In addition, the ball screw nut should generally not be removed from the spindle. As a result, the balls that are necessary for the transmission of force may fall out.

Question:

How long does a ball screw lasts?

Answer:

How long a ball screw can withstand an application depends on many factors. Therefore, it is not possible to say generally how long a ball screw will last. When a ball screw should be replaced, it must be determined mathematically. In the following link, you will find the appropriate calculation formula for the lifetime available as a PDF.

Question:

How large is the axial play of a ball screw?

Answer:

The axial play varies depending on the precision class and size of the ball screw. You can find the appropriate axial play for different ball screws under the selection Ball Screws available as a PDF .

Question:

What must be considered when installing a ball screw?

Answer:

When installing a ball screw spindle, more must be taken into account than just ensuring that it is installed tension-free. There are a few things you should observe even before installation. You can view these as a PDF under Precautions.

Question:

Are the ball screws lubricated?

Answer:

The ball screws from MISUMI are pre-greased. Various lubricants are available for this purpose. Lithium-saponified lubricants are used as standard lubricants. In addition, MISUMI offers heat-resistant lubricants or lubricants suitable for cleanrooms. You can find further information under Installation and Maintenance available as a PDF.

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