Table of Contents

  • Track rollers
    • Features
      • Possible combinations of track rollers and guideways
    • Design and safety guidelines
      • Adjacent construction for non-locating bearing track rollers

Track rollers

Features

Track rollers LFR are double row angular contact ball bearings comprising an outer ring with a gothic arch profile, an inner ring and two ball and cage assemblies with plastic cages. The inner ring and outer ring are made from rolling bearing steel 100Cr6.

The special outer ring gives two point contact in the contact zone with the raceway, ➤ Figure. The contact angle α is a maximum of 30°.

The bearings can support axial forces from both directions as well as radial forces.

Gothic arch, two point contact, contact angle
α = 30°
 Gothic arch raceway groove
Track roller with extended inner ring

Track rollers LFRI are double row angular contact ball bearings. They differ from track rollers LFR in that they have an extended inner ring. This allows exact positioning in the adjacent construction. The inner ring is mounted by means of a standard screw (for example ISO 4762) in a fit hole (preferably grade F6). The fixing screw is not included in the scope of delivery. The operating clearance of track rollers with an extended inner ring cannot be set by means of eccentric bolts.

Track roller LFRI with fixing screw
Sealing and lubrication

Gap seals on both sides protect the rolling element system against contamination. Bearings with this seal type have the suffix 2Z.

The track rollers are also available on request with contact seals on both sides, suffix 2RS and 2RSR.

The track rollers are greased for life and are therefore maintenance-free. From outside diameter ≧ 52 mm, the inner ring has a lubrication bore.

Seal types

Seal types and their specific features: see table .

Specific features

2Z seal

not radially preloaded

low friction

to be used with low levels of contamination.

2RSR seal

radially preloaded

to be used with higher requirements for sealing action and under heavy contamination.

2RS seal

axially preloaded

to be used with higher requirements for sealing action and under heavy contamination.

Corrosion-resistant design

The inner ring and outer ring are made from corrosion-resistant steel. The rolling elements are protected against corrosion by the grease.

Corrosion-resistant designs have contact seals and the suffix 2RS-RB or 2RSR-RB.

Accuracy
and internal clearance

The dimensional and geometrical accuracies correspond to tolerance class PN to DIN 620.

The radial internal bearing clearance corresponds approximately to internal clearance group Group N in accordance with ISO 5753-1; internal clearance classes: see Catalogue HR 1, Rolling Bearings.

Possible combinations of track rollers and guideways

The tables show the possible combinations of track rollers with the guideways LFS and shaft and support rail unit TS.

Combinations with guideways LFS

Width and shaft diameter**

Track roller LFR

LFS

dLw

50/5-4

50/5-6

50/8-6

5201-10

5301-10

5302-10

20

4

●

‒

‒

‒

‒

‒

25

6

‒

●

●

‒

‒

‒

32

6

‒

‒

●

‒

‒

‒

42

10

‒

‒

‒

●

●

●

52

10

‒

‒

‒

●

●

●

86

10

‒

‒

‒

●

●

●

120

10

‒

‒

‒

●

●

●

●

available size

** Width b and shaft diameter dLw.

Combinations with guideways LFS

Width and shaft diameter**

Track roller LFRI

LFS

dLw

50/8-6

5201

20

4

‒

‒

25

6

●

‒

32

6

●

‒

42

10

‒

●

52

10

‒

●

86

10

‒

●

120

10

‒

●

●

available size

** Width b and shaft diameter dLw.

Combinations with shaft and support rail units TS

Shaft diameter

Track roller LFR

dLw**

5201-12

5204-16

5206-20

5206-25

5207-30

5208-40

5308-50

12

●

‒

‒

‒

‒

‒

‒

16

‒

●

‒

‒

‒

‒

‒

20

‒

‒

●

‒

‒

‒

‒

25

‒

‒

‒

●

‒

‒

‒

30

‒

‒

‒

‒

●

‒

‒

40

‒

‒

‒

‒

‒

●

‒

50

‒

‒

‒

‒

‒

‒

●

●

available size

**Shaft and support rail units TS and shaft diameter dLw: see Catalogue WF 1, Shaft Guidance Systems.

Design and safety guidelines

Adjacent construction for non-locating bearing track rollers

For non-locating bearing track rollers without an inner ring, the rolling element raceway on the shaft must be hardened and ground. The surface hardness must be 670 HV + 170 HV. The hardening depth CHD or SHD must be sufficiently large.

Tolerances and surface data for the shaft raceway

Design of the shaft: see table .

Diameter tolerance of shafts

Roughness

Roundness

Parallelism

without
inner ring

with
inner ring

max.

max.

max.

k5

g6
(under point load)

Ra 0,4 (Rz 2)

25%
of diameter tolerance

50%
of diameter tolerance

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