Linear-motion bearing

Linear ball bearing or short linear bearings, colloquially also called ball bushings or ball bushings, special ball bearings with an exceptional, because axial (rather than radial ) ball. The purpose of this bearing is not (as in all the other rolling bearings ) supporting a rotating element, but the low friction as possible the translational guidance, ie rectilinear movement of a machine element along a cylindrical shaft. The result is one of several types of special linear guide, the so-called wave guide. A distinction between fixed bearing and bearing, as usual in rolling bearings therefore is useless in the linear ball bearings.

In these linear systems without stroke limiter are in point contact between the bearing balls of the bearing and the shaft. The permissible load of a linear ball bearing depends on the number of supporting rows of balls. Earlier linear ball bearings were made of high carbon bearing steel which was ground after hardening inside and outside.

An outer ring but today's linear bearings have more than one race plates on the outside diameter of the bearing ( one per ball ), on which the rolling balls in linear bearings. The race plates modern linear bearings are mounted in a plastic housing which also serves as a ball cage and takes over the function of the ball return. Instead of an inner ring, the balls inside run directly on a shaft of precision steel. This design has now almost completely replaced the previously used full- steel version.

Linear bearings are available both without and with single or double seal on the front sides.

When axial ball in the linear ball bearing only the inner, bearing row of balls is always charged while the outer, balanced ball series against the stock movement direction by a ball deflection and the ball return moves back to the second ball deflection at the starting point of the load zone.

Linear ball bearings as the bearings are similar standardized in different dimensions offered. Various ISO series ( eg ISO series 1 or ISO Series 3 ) define the exact inner and outer diameters and the lengths of these camps.

Typically the linear ball bearing sizes are defined by the internal diameter. ( Nominal diameter )

DIN designation for linear bearings

In the list of DIN standards can be found under the standards DIN 636 and DIN 644 Linear rolling bearings, for which according to DIN definition not only the linear ball bearings, but also

The designation according to DIN does not correspond to the normal market terms. With market conditions, for example, the term linear ball bearing, also known in older parlance ball bushing.

Use of linear ball bearings

Linear ball bearings are used in many technical applications, such as computers and peripherals ( such as scanners ), automatic registration systems, 3D measuring devices (eg multi-spindle drilling machines and other precision machinery), presses, machine tools and machining centers including those doors, automatic cutting machines, printing machines, card selection machines, food packaging machines their use.

Furthermore, linear ball bearings can be used to build linear stages and other shifters. Thus there are, for example, at the foot under the chairs of the front rows in the Plenary Hall of the German Bundestag corresponding displacement units on the basis of linear ball bearings that allow the deputies sitting there a reciprocating motion in her chair.

Manufacturer of linear ball bearings

Manufacturer of linear ball bearings are, inter alia, large, producing in Germany industrial groups of the bearings and mechanical engineering industries such as Bosch Rexroth, the Schaeffler Group ( INA, FAG) or Svenska Kullagerfabriken (SKF ) and various medium and small enterprises from the European, American and Asian countries.