Technical Details - Carry

Carry screws are manufactured by the highly economical cold-rolling process which offers both significant cost savings but also maintains a precision previously often only available with machine-ground screws. Carry screws are complemented by a range of single steel nuts produced in a special cost-cutting process.

Carry offers all the advantages of the inherent ball screw design:

  • high efficiency, i.e.
    • low power input
    • low self-heating
  • low frictional, stick-slip-free running
  • maximum wear resistance, i.e. very good repetition accuracy with a constant positioning precision.
  • high reliability and durability.

Materials

  • standard: steel 100 Cr6 (1.3505) and Cf53 (1.1213)
  • on request: stainless steel  X46Cr13 (1.4034)
  • other materials on request

Attention: The use of stainless steel results in lower load rates; details on request.

Nut designs

Cylindrical single nut type ZY... Nut with mounting thread type FG... 

Standard are the following three types:

  • Cylindrical single nut type «ZY…»
  • Nut with mounting thread type «FG…»
  • Flange nut type «FB…»

Other nut designs (such as those with integrated cardanic axis) are available upon request.

Ball return

Singel-thread ball return, type ..I

 

 








Tube type ball return, type ...R

Nuts feature

  • Single-thread ball return, type «…I»
    or
  • Tube type ball return, type «…R»,

both are fully integrated into the nut shape.

Thread profile

Gothic arc (ogival) thread profile

Used most commonly are gothic arc (ogival) profiles.

Operating temperatures

Regular applications: – 20 to + 80 °C.
Please ask about other operating temperatures.

Lead accuracy

Eichenberger ball screws feature the following lead accuracies according to DIN 69051:

Standard

  • G9 = ≤ 0,1 mm/300 mm

On request
  • G7 = ≤ 0,052 mm/300 mm
  • G5 = ≤ 0,023 mm/300 mm

Reduced backlash

If necessary, reduced backlash up to ≤ 0.01 mm is available (only with paired or assembled screws).

Efficiency

diagram

The efficiency η  for Carry ball screws is better than 0.9.

Wipers

K = Plastic wipers B = Brush wipers F = Felt rings

Plastic (K) or brush (B) wipers are used, depending on nut type/dimension. Felt rings (F) available on request (for lifetime lubrication).

Lubrication

The usual specifications for lubricating ball bearings also apply to ball screws. However, lubrication applied only once but intended to last a lifetime is not sufficient in most cases. Regular lubrication is required to extend the service life of the ball screw.

Please note:
When shipped, screws simply have a protective film. Before mounting or operating the ball screw, units must be lubricated with the proper lubricant (through the lube hole for nuts with wipers; directly onto the screw for nuts without wipers).

Recommended all-purpose lubricant:

  • Klüber Microlube GBU Y 131 - Available here

When using another lubricant, please verify compatibility with anticorrosion agent; otherwise rinse ball screw unit prior to lubrication.

Caution: Do not use grease containing graphite or MoS.

Factory length

In general, Eichenberger screws are available as threaded rods, approx. 2.8 to 3 m long. Upon request, lengths up to 6 m are available, depending on diameter and supply market situation.

Ball screw ends

illustration

Ball screw ends are without any machining cut by grinding (standard).

Upon request, end machining is available. Dimensions are as per customer specifications. Screws may also be ordered with softened ends for subsequent finishing by the customer or with an application-specific end journal. In each instance, a detailed drawing would be necessary.

Handling

Ball screws are precision parts and must be protected from shock, dirt or moisture when transported or stored. Please do not unpack until ready for use.

Please check for cleanness when mounting the ball screw. Dirt or foreign matter on the ball race – especially inside the nut – may cause increased wear and premature failure.

Please consult lubrication recommendation before mounting or operating ball screws.

Radial loads and torque

Radial loads or torque brought to bear upon the nut result in overload of individual contact surfaces, thus seriously affecting the service life of the ball screw assembly. Therefore it is important to properly mount the screw and to comply with all relevant form and positional tolerances.

Assembling of ball screw units

1. Remove transport lock (O-ring) on one side. Please keep sleeve and nut in horizontal position. Otherwise, the nut may slide from the sleeve and balls may fall out of the ball race.
In the event such incident does occur, balls must be properly re-inserted to prevent damage to or blockage of the ball screw. If in doubt, please contact Moore International.

2. Insert screw end into mounting sleeve.

Caution: Operator must be able to advance sleeve up to the thread intake. Otherwise, balls may fall out of the ball race and damage or block the unit.

3. Gently turn nut onto the screw.