MAC Marketing Corporation offers roller screws, which are available in 2 general versions. A Roller screw can be equipped with satellite-rollers and is combining a ground screw, a nut and the satellite-rollers. Both, the screw and the nut have a multi-threaded thread profile with flank angles of 90°. The satellite-rollers are guided by sprockets and kept in a defined distance from each other that way. Roller screws are available with and without preload. To protect from dirt or dust, roller- screw nuts can be equipped with wipers made from PA66.

Roller screws with roller circulations do not use satellite-rollers. They are using rollers with grooves on their out- side diameter, which are arranged with the distance of the relative pitch. They offer relatively small pitches even with big screw-diameters and achieve high positioning - accuracies and repeatabilities, as well as a high efficiency.

The characteristics of roller screws are:

• High axial load capacity by the use of thread- rollers and the resulting contact areas, as well as the amount of contact points
• High speed, high acceleration
• High axial rigidity
• High positioning-accuracies and repeatabilities with short strokes
• Dimensions according to customer drawings

Travel Variation:

• Class: Variation per 315 mm
• KI 10: ± 0,01 mm
• KI 5: ± 0,005 mm

Lubrication: All ball screws need to be lubricated to ensure proper function. The way and the frequency of lubrication depend a lot on the relevant product. The definition of lubrication-volumes and cycles are very much depending on the application and can be determined by our technical department. The information about grease- and oil-lubrication given below refers to usual industrial applications and is not generally binding. Especially in special cases, i.e. food-industry, high-temperature or high-speed-applications, or short-stroke-applications need to be looked at individually.

Preload: By preloading roller screws, a higher rigidity and positioning-accuracy is achieved. At the same time the friction- and start moment, as well as the lifetime is influenced. Splitted nuts will be preloaded by ground shim rings, which are put between the two nut-halfs. As soon as the nut is affected by axial force the nut-halfs will be pushed together, while the shim rings will then support to control that axial force. Non-splitted nut are preloaded by selecting according sizes of nuts and rollers.

Assembly and maintenance: Roller screws are only supposed to handle axial loads. When assembling roller screws, it is important to avoid radial or excentric loads or install an extern guide to sup- port those loads. The roller screw nut may not be removed from the roller screw without an assembly sleeve. To prevent damages, limit switches or dampers must be considered in the machine. Roller screws are to be protected against dirt.

Temperatures: The allowable permanent temperature is between -20°C and +80°C. Temporary variations are possible, but should be check in advance.

About the company: MAC, established in 1987, is engaged in the field of rolling bearings and allied products including water lubricated bearings, stainless steel bearings, self – lubricating bearings, slewing ring bearings, ceramic ball bearings, hydrostatic bearings, combined bearings, rod end bearings, wire race bearings, and many more, ranging from 1 mm dia up to 7000 mm dia. It has an experience of 4 decades about the slew bearing in stacker reclaimers, mounting stations, etc.

For details, contact MAC Marketing Corporation, Bangalore, on Tel: +91 80 2351 6096, Mob: +91 98450 18280, or Email: info@macmktg.com