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iglidur® Q: able to withstand high loads, even when subjected to the strain of tumbling

The customer uses lubricated brass bearings that run on customer's steel shafts (Figure 1). Application data were also provided. (Table 1).
The igus® laboratory carried out tests in order to compare the wear of different iglidur® materials with competitors' bearings and find the ideal material for this application.

Brass bearings and customer's shaft

Figure 1: Brass bearings and customer's shaft

Table 1: Application parameters

Parameters Value
Bearing material Brass bearings (competitor's); iglidur® Z; iglidur® Q
Shaft material Steel
Movement Displacement: tumbling (with bulldozer effect)
Speed 0.15 m/s (corresponds to 74 rpm in the test)
Cycle 4 rotations (10 s), 90 s pause
Load 3 MPa to 28.5 MPa (increases every time a rotation is completed)

There was no standard test set-up for the application parameters indicated. For this test, a new test set-up (Figure 2) was planned, designed and built - For the test, a constant load instead of an increasing load was used in order to expedite the test and keep it relatively simple.
In order to be able to rule out temperature influences due to continuous movement - something that differs from the real conditions of use -, a test interval of 6 s movement and a 54 spause was set.

Test set-up

Figure 2: Test set-up
The tests were carried out dry and also with initial lubrication. The lubricant used for the test was OKS 400. The results of the tests are compared in Table 2 and Figure 3.


Wear when subjected to the stresses of tumbling (bearing moves around the shaft = Bulldozer effect) :

iglidur® Z bearings, iglidur® Q bearings and competitors' bearings made of brass were tested dry as well as with lubrication on the customer's steel shaft; p = 14.67 MPa; n = 74 RPM

Test results

Y = Wear rate [µm/km]
Figure 3 : Test results
The wear of iglidur® Q when dry and also when lubricated is the lowest in this test. In addition, the tested parts were subjected to a visual inspection. The results are shown in Figure 4, Figure 5 and Figure 6.

Figure 4: Brass bearing with associated shaft after being in operation (examples)

Marks on the bearings and shaft were visible.

With lubrication
Test of iglidur® Q  
Test of iglidur® Q  
Figure 5: iglidur® Z bearing and associated shaft after being in operation (examples)

There are almost no visible signs of damage on the sliding surface.
The bearings have a few marks on the inner diameter surface caused during initial wearing-in of the bearings.

With lubrication
Test of iglidur® Q  
Test of iglidur® Q  
Figure 6: iglidur® Q bearing and associated shaft after being in operation (examples)
With lubrication
Test of iglidur® Q  
Test of iglidur® Q  


In this test, the iglidur® Q material showed the least amount of wear and had the best results in the test bay.
The worst results were exhibited by the tested brass bearings due to the high level of bearing wear and the damage to the shaft.

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