Linear bearings and linear bearing and housing units
Features
Linear bearings and linear bearing and housing units are available in the compact, light, heavy duty, machined and plain bearing range. The bearings can support high loads while having a relatively low mass and allow the construction of linear guidance systems with unlimited travel.
Each series has highly specific characteristics that precisely define it as suitable for particular applications. These may include, for example, requirements for compensation of misalignments, low-friction running, high accelerations and travel velocities or long operating life.
The range, which has been constructed and expanded in accordance with a modular concept, provides the best technical and economic solution, in relation to each application, for bearing arrangements with shaft guidance systems.
Linear bearings
Linear ball bearings and linear plain bearings are available in open or closed designs. The open design has a segment cut out and is intended for supported shafts. Several series allow, in conjunction with the corresponding housings, adjustment of the radial clearance in order to achieve clearance-free or preloaded guidance systems.
Compensation of misalignment
Misalignment can be caused by tolerance defects, mounting errors or inaccuracies in the adjacent construction. Linear ball bearings of the series KN..-B and KNO..-B can compensate static misalignment of up to ±30′, linear ball bearings of the series KS and KSO can compensate static misalignment of up to ±40′, ➤ Figure.
Compensation of misalignment by KN..-B and KS
Due to the self-alignment function, the balls run without difficulty into the load zone. At the same time, the load distribution over the whole ball row is more uniform. This leads to smoother running, allows higher accelerations and prevents overloading of the individual balls.
Overall, this means that the bearings can achieve higher loads and a longer operating life; if necessary, the adjacent construction can be designed to be smaller and more economical.
ACHTUNG
In order to fully utilise the basic load ratings given in the dimension table, the shaft raceway must be hardened (670 HV + 165 HV) and ground.
Linear bearing and housing units
Linear ball bearings and plain bearings are also available in conjunction with INA housings as complete bearing units. The linear bearing is located in the housing by means of a radial fixing screw to prevent axial displacement.
The housings are made from a high rigidity, high strength aluminium alloy that allows the full load carrying capacity of the bearings fitted to be utilised. In the machined series, pressure diecast housings are also available.
Due to the comparatively low total mass, the units are particularly suitable for reduced mass designs with high loads and where higher accelerations and travel velocities are required.
Simple location
Threaded or counterbored holes in the housing allow straightforward screw mounting on the adjacent construction, if necessary from below.
For rapid alignment, the housings have a locating edge. This also prevents distortion of the linear bearings when the housings are being mounted.
Centring holes allow rapid additional location of the housings by dowels on the adjacent construction.
Housing designs
The housings are available in closed design, with a segment cutout and in open, slotted and tandem versions (with and without a centring collar).
Closed design
In this variant, the bearings and housings are closed. As a result, high precision standard guidance systems with a fixed enveloping circle can be easily achieved.
With segment cutout
Open designs with a segment cutout are used where, in the case of long guidance systems, the shaft must be supported and the bearing arrangement must be highly rigid.
Slotted design
Closed designs and designs with a segment cutout are also available in several series with a slot. Slotted variants are suitable for clearance-free or preloaded guidance systems. The operating clearance is set by means of an adjusting screw.
Tandem design
The tandem version contains two linear bearings. As a result, the units have particularly high load carrying capacity.
Tandem ball bearing and housing units are available in open and closed designs. Both variants are also available in the named design with a slot.
With centring collar
For special applications, there is also a tandem version with a centring collar for locating bores to H7.
Highly cost-effective
As a result of volume production in large quantities, the complete units are normally considerably more economical than customers’ own designs.
Sealing
The bearings are available in an open version and with contact seals on both sides (suffix PP). The linear bearings of type KH, KN..-B and KB have seals with two seal lips on their end faces; the outer lip prevents the ingress of contamination, the inner lip retains the lubricant in the bearing. The linear bearings of type KS have contact seals with one seal lip.
Lubrication
Due to the initial greasing with a high quality grease and the integral lubricant reservoir, the linear bearings are maintenance-free for many applications; if necessary, however, they can be relubricated.
Linear ball bearings can be lubricated, depending on the design, via the openings in the outer ring or radial holes arranged in the centre of the bearing.
In the units, lubrication is carried out via a separate lubrication nipple in the housing; location of the bearing in the housing and the relubrication devices are thus separate from each other.
Operating temperature
The bearings and housings can be used at operating temperatures from –30 °C to +80 °C.
Operating limits
The table shows the operating limits for linear bearings.
Once the interrelationships of bearing size and design, load, operating clearance, location of bearings and lubrication have been checked, it may be possible in individual cases to use higher values. In this case, please contact us.
ACHTUNG
Linear bearing and housing units should be allocated in accordance with the linear bearing fitted.
Dynamic values
for linear bearings
Acceleration, | Linear bearing series | ||||
|---|---|---|---|---|---|
KH | KN..-B | KB | KS | PAB | |
Acceleration | 50 | 50 | 50 | 100 | 50 |
Velocity | 2 | up to 5 | up to 5 | up to 5 | up to 3 |
In the case of linear ball bearings with seals, suffix PP, velocities up to 2 m/s are permissible.
Suffixes
Suffixes for available designs: see table.
Available designs
Suffix | Description | Design |
|---|---|---|
PP | Lip seals on both sides | Standard |
PPL | Sealing strips on bearings | Available by agreement |
AS | Bearing and unit with relubrication facility | Standard |
Compact range
Linear ball bearings KH and linear ball bearing and housing units of the compact range have a small radial design envelope and are particularly economical. Their low section height automatically makes them attractive for applications in which only a small amount of radial space is available.
Due to the closed design, they are suitable for use with shafts.
Linear ball bearings
The bearings have an outer ring with openings. This contains a ball and cage assembly with a plastic cage. The outer ring is formed and hardened. The balls undergo return travel along the openings in the outer ring.
Seals
The bearings are available in an open version and with lip seals on both sides (suffix PP). The end face seals have two seal lips; the outer lip prevents the ingress of contamination, the inner lip retains the lubricant in the bearing.
Linear ball bearing and housing units
Linear ball bearing and housing units of the compact range are available with one integral bearing and, in the tandem version with particularly high load carrying capacity, with two bearings.
The housings are made from high strength aluminium.
Anti-corrosion protection
The housings are two-piece components made from sheet steel with a Corrotect coating. The bearings and housing parts are packed separately. The bearing is firmly seated once it is mounted in the housing.
Light range
The light range is available as linear ball bearings KN..-B of a closed design and as linear ball bearings KNO..-B with a segment cutout.
In order to compensate misalignments arising from manufacturing tolerances, mounting errors and shaft deflection, the linear bearings of series KN..-B are self-aligning up to ±30′.
Their robust construction allows operation even under aggressive operating conditions.
The series KN..-B is of a closed construction and is designed for use with shafts. KNO..-B has a segment cutout and is used with shaft and support rail units.
Linear ball bearings
Linear ball bearings KN..-B and KNO..-B comprise a plastic cage with inserted raceway plates. The plates are supported in the housing bore by means of a retaining ring. Due to the retaining ring, the plates can “rock” and thus compensate for static misalignments.
Seals
The bearings are available in an open version and with lip seals on both sides (suffix PP). The end face seals have two seal lips; the outer lip prevents the ingress of contamination, the inner lip retains the lubricant in the bearing.
Heavy duty range
Linear ball bearings of the heavy duty range KS and KSO and the corresponding ball bearing and housing units have particularly high load carrying capacity and have an angular adjustment facility for compensation of misalignments. They have very good running characteristics.
Linear ball bearings
Linear ball bearings KS and KSO comprise a plastic cage with loosely retained segments. The double row segments with crowned raceway plates can realign themselves in all directions and thus compensate misalignments. Since the complete segment undergoes realignment, there is no disruption to the recirculation of the balls. This results in uniformly low displacement resistance.
The series KS is of a closed construction and is designed for use with shafts. KSO has a segment cutout and is used in conjunction with shaft and support rail units.
Seals
The bearings are available with contact seals or gap seals. The contact seals on the end faces have two seal lips; the outer lip prevents the ingress of contamination, the inner lip retains the lubricant in the bearing.
Linear ball bearing and housing units
Linear ball bearing and housing units of the heavy duty range are available with one integral bearing and, in the tandem version with particularly high load carrying capacity, with two bearings.
The housings are made from high strength aluminium.
The housings are available in a closed design, with a segment cutout for supported shafts and with or without a slot. In designs with a slot, the radial clearance can be adjusted by means of an adjusting screw.
All series have a locating edge and centring holes for dowel holes.
The bearings are sealed on both sides, they have an initial greasing and can be relubricated via a lubrication nipple in the housing.
Machined range
Linear ball bearings of the machined range KB, KBS and KBO and the corresponding linear ball bearing and housing units are high precision and particularly rigid. They have excellent running characteristics.
Linear ball bearings
Linear ball bearings KB, KBS and KBO comprise a hardened and ground outer ring in which a ball and cage assembly with a plastic cage is integrated.
The balls are guided with high precision throughout the return area by a special spring washer. This ensures that the displacement resistance remains uniformly low even under difficult operating conditions and irrespective of the mounting position.
The series KB is of a closed construction and is designed for use with shafts. KBO has a segment cutout and is used in conjunction with shaft and support rail units. KBS has a slot for adjustment of the radial clearance.
Seals
The bearings have contact seals or gap seals.
Linear ball bearing and housing units
Linear ball bearing and housing units of the machined range are available with one integral bearing and, in the tandem version with particularly high load carrying capacity, with two bearings.
The housings are made from high strength aluminium or are pressure diecast.
The housings are available in a closed design, with a segment cutout for supported shafts and with or without a slot. In designs with a slot, the radial clearance can be adjusted by means of an adjusting screw.
All series have a locating edge and centring holes for dowel holes.
The bearings are sealed on both sides, they have an initial greasing and can be relubricated via a lubrication nipple in the housing.
Plain bearing range
Linear plain bearings PAB and PABO and the corresponding plain bearing and housing units have very high load carrying capacity, are extremely robust and have particularly low running noise. They have excellent emergency running characteristics.
Linear plain bearings
Linear plain bearings PAB and PABO comprise an outer ring made from high strength aluminium into which plain bearing bushes EGB..-E50 are fixed by adhesive.
The series PAB is of a closed construction and is designed for use with shafts. PABO has a segment cutout and is used in conjunction with shaft and support rail units.
ACHTUNG
Plain bushes must not be used in conjunction with the special coating Corrotect. Crevice corrosion may occur that would impair the function of the bearing.