State of the art Technology

Various types of wipers, made of felt or plastic, for example, are available to protect ballscrews from dirt and contamination:

Standard wipers:

In normal applications, wipers made of POM plastic are used. For higher demands on temperature stability, special plastic made of PTFE can also be used.

Vulkollan wipers:

Vulkollan wipers are set apart by very good dynamic characteristics and high wear-resistance. The edges of the wipers are very close to the ballscrew spindle, thus reducing the loss of lubricant. The frictional torque of the ballscrew will be increased. These wipers are not available for all dimensions.

Felt wipers:

If the ball screw needs special protection against fine dust, the use of felt wipers is recommended. It should be noted that the friction torque of the ball screw drive is increased. These wipers are not available for all dimensions.

No wipers:

In an application without a wiper, a regular lubrication interval or oil lubrication according to ours Lubrication instruction be provided.

In order to prevent dirt from entering the nut system, additional protective measures such as a bellows may be necessary.

When designing a ballscrew, attention should be paid to the critical bending speed – at this point, resonances occur at the spindle – and the maximum speed, both of which are determined to a large extent by the nut design and by the type of ball return system used. 

The dynamic load rating is the central axial load that a ball screw drive can withstand for a nominal service life of XNUMX million circuits.

This value should be used for the design of the ball screw. Karl Hipp GmbH recommends a maximum load of approx. XNUMX% of the dynamic rating for continuous operation.

It is recommended that no radial or eccentric forces act on the nut system when installing ballscrews.

When assembled, the nut should move easily at any position on the ballscrew. Any misalignment and the resulting tension can be determined most easily near the bearing or at the extreme end of the spindle.

The ballscrew assembly must be assembled with great care, as tensions and misalignments reduce the service life and can lead to premature failure.

Please also note ours Instructions for use.

The lifetime (nominal life) is expressed by the number of circuits that XNUMX% of a sufficiently large number of ballscrews achieve or exceed before the first signs of material fatigue occur. This figure is expressed in circuits or hours.

For continuous operation, the Karl Hipp GmbH a maximum load of approx. XNUMX% of the dynamic load rating is recommended.

• Low-play single nut
• Anti-backlash pre-loaded single nut (4-point pre-loading)
• Anti-backlash, pre-loaded double nut
• Spring pre-loaded double nut

The Karl Hipp GmbH has been certified according to DIN EN ISO 1997 since 9001. All ballscrews go through measuring and testing procedures according to the latest knowledge and are provided with a corresponding coding. On request, we create measurement reports about:

• Lead accuracy
• Torque
• Dimensional tolerances
• Tolerances of shape and position

Radial loads can occur due to installation tolerances, but should be kept below 5% of the lowest axial load if possible.

In principle, the same lubricants as for ball bearings can be used to lubricate ballscrews. It must be ensured that the lubricants have the same saponification base.

The initial greasing is carried out with Staburags NBUXNUMX / XNUMXKP as standard.

As a rule, the ball screw drive is not designed for permanent lubrication, since grease can be continuously discharged through the ball screw spindle despite the appropriate wipers.

A corresponding maintenance interval is therefore provided by the Karl Hipp GmbH expressly recommended and should be adapted to the application. With manual relubrication, careful cleaning of the ball screw must be ensured. More information can be found in our general Lubrication instruction.

The choice of lubricants depends on various factors. The most important are spindle speed, ball speed, operating temperature and the load on the ball screw. Special lubricants for vacuum and clean room applications are also available, please contact us if you have any questions.

The basic static load rating is an axial, centrically acting load, which corresponds to a total permanent deformation of the ball or the ball track of 0,0001 x ball diameter in the contact area of ​​the ball or ball track that is subjected to the highest stress.

The basic static load rating describes the maximum possible static load on the ballscrew. Reaching or exceeding this value leads to permanent deformations on balls or the thread profile, which results in irreparable damage.

The rigidity of a ball screw, together with the geometric accuracy, also influences the positioning accuracy of a ball screw. We achieve very good stiffness values ​​with our miniature ballscrews via the so-called 4-point preload.

The stiffness can be increased and adjusted via the preload, using an oversize ball. However, it should be noted that a high preload has a negative impact on the service life.

The preload is the axial force within the nut system to increase the positioning accuracy. Due to the highest precision and form accuracy of our ballscrews, our ballscrews can be preloaded as standard using the 4-point preload. This is how we achieve the highest load ratings. For applications with minimal torque fluctuations, miniature ballscrews with spring-loaded double nuts can also be supplied.

As pre-loading results in absence of play and increased stiffness of the ballscrew, but also significantly affects the service life and rolling characteristics, it should be applied “as little as possible but as much as required”. If you have any questions, please contact us for consultation.