TECHNICAL INFORMATION ABOUT BALL TRANSFER UNITS
Operating conditions:
The ball transfer units are mainly used with conventional orientation, with main ball facing up; some versions allow the “upside down” use, that is with main ball facing down: in this case it has however to be considered that it involves a reduced loading capacity and smoothness.*
Ball transfer units are usually used at “room temperature” and preferably in so called “dry places”.
In presence of particularly high temperatures or critical weather conditions, we recommend using versions carried out in suitable materials or considering the use of special treatments/sealing coatings*.
FRICTION COEFFICIENT OF THE BALL TRANSFER UNITS
Considering a correct application and the use in optimal environments, the friction coefficient of ball transfer units in steel, can be as follows*:
( % of the transported mass)
| High Performance | 0,5% |
| Medium Performance | 2% |
| Low Performance | 3% |
How to determine the type, quantity and distance of ball transfer units to be used:
Dividing by 3 the total weight of the load intended to be moved, you get the entity of the load to be placed on each single ball transfer unit and therefore the most suitable version of ball transfer unit. The result of this division represents the maximum load that each ball transfer unit can support, even if a safety margin has to be considered. This, always considering the conventional orientation.
The supporting surface of the ball transfer units has to be rigid and aligned enough, so that the ball transfer units are subjected to equal stress in supporting the load. It is at the same time important that the surface of the load to be handled is rigid enough to avoid it being damaged by the ball transfer unit intended to support it.
Example: Weight = 500N
LOAD “F” for the ball transfer unit = 500/3= 166 N
The optimal distance (a) between the ball transfer units is calculated dividing by 3 the smallest side of the load. The obtained result states the necessary space between one ball transfer unit and the other one ensuring that there is a sufficient number of elements to support the load.
Distance between ball transfer units : 300/3= 100 mm
Positioning of the ball transfer units:
According to the version in use, there are different positioning modes; the ball transfer units with flange for example allow to be simply inserted into apposite holes created on the support table while other versions may require fixing through screws and rivets or, again, there are ball transfer units provided with threaded shank or internal thread.
A further help is represented by the fixing clips in removable or fix versions and tolerance rings, which can be supplied directly by us. Finally, we carry out ball transfer units with “seeger groove”, at different heights, to allow the use of seeger rings according to DIN 471 Standards.
OTHER TECHNICAL SPECIFICATIONS
Lubrication
Ball transfer units with steel balls are usually provided with felt seal to protect them from dust and impurities, lubricated with technical white oil. On request they can be produced with dry felt seal or without felt seal.
Maintenance
Periodical maintenance cycles should be provided, taking into consideration the operating criticism level. It is possible to proceed with simple jets of compressed air or, if necessary, wash them paying attention to choose the suitable detergents. In particularly critical environments, the use of a common unblocking product may be required to restore the smoothness.
Most of the ball transfer units of our production are provided with a hole on the bottom to allow the exit of impurities.
Speed
The recommended maximum rolling speed is 1 m/sec.
Shocks and overloads
A wrong positioning, mounting or levelling of the ball transfer units may cause malfunctions resulting from overloads and/or shocks, which can lead to the breakage or block of the same. To grant the smoothest performances and duration, it is therefore important to make sure that they are correctly placed and mounted.
Nominal life
The approximate nominal life of a ball transfer unit can be determined using the following formula: L =(C/F)3 X 106 where L= nominal life duration (rotations) ; C=Load capacity in N; F= Load in N.
*For any further information please do not hesitate to contact us.
NOTE: All dimensions stated in the technical datasheet are subjected to machining tolerances and, although the drawings are faithful, they are not binding. EFFECIESSE S.R.L reserves the right to modify products without notice.