ITS Italia.
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LINEAR BALL BEARINGS FOR LINEAR MOVEMENTS ( KB, KB_O , KB_J )

JFK sleeves for linear movements are make up  by a cylindrical outer ring,from a cage for retaining the spheres,by two end rings for the holding of the cages  and / or , if required , by two sealing rings. The components are mounted so as to optimize their functions.

The outer ring is subjected to a special heat treatment, such that it has a hardness as to ensure to the sleeve a very satisfactory life both in terms of distance travelled that in hours.

The cage restraint of the balls can be made of steel or polyamide, and the outer ring is retained by two end rings .

The steel cage offers a high stiffness and a good mechanical resistance.

The polyamide cage reduces the total weight of the sleeve.

The sleeves for linear movements have the following construction characteristics :

  • precision and rigidity : this because they present an outer ring in steel in which is coupled a pressed steel cage or alternatively a cage in polyamide
  • ease of assembly: as they can withstand the loads acting in any direction
  • ease of replacement : this because they are interchangeable
  • availability of a complete range : JFK is able to offer an extended range of sleeves

- closed execution

- adjustable running

- open execution

The sleeves for linear movements are produced in standard accuracy .

An excessive recording with relative outer ring deformation influences the precision of sliding and its duration.

The coupling shaft / sleeve  and housing / sleeve it must be such as not to affect the proper operation of the linear system .


The felt rings used as additional seals for sleeves " JFK " help to improve the lubricating effect and , at the same time extend the maintenance.

The sleeves for linear movements operate at temperatures between -20 ° C up to + 110 ° C .

JFK linear ball bearings  are precision components ; therefore must be handled with care.
ITS Italia recommends some details:

  • handle the product with care : so avoid that the linear systems fall or suffer shock
  • control the size of the adjacent parts : to take full performance of linear systems is necessary to make sure the size of the place , of the shaft and the mounting surface of the guide are appropriate and accurate.
  • correct cleaning : as foreign " bodies " have a negative influence as they cause damage to or failure of the system itself.

The use of linear systems without lubrication increases the wear phenomenon of the rolling bodies , reducing the effective duration. For this reason they require adequate lubrication to be performed with for turbine oils  for turbine or with lithium soap. The linear systems can have seals to prevent the inclusion of dust , foreign particles and to retain lubricant . In the case where they are used in contaminated or corrosive environments, ITS Italia recommend applying an additional protective cover on the components that enclose the linear system   

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