Page 63 - IGUS Bearing

iglidur | Technical data iglidur | Technical data
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Assembly instructions Tolerances and measurement system

iglidur plain bearings are press-fit bearings. The inner The installation dimensions and tolerances of the iglidur
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diameter adjusts only after press-fit in the proper housing plain bearings are a function of the material and wall
hole with a recommended (H7) tolerance. The press-fit thicknesses. For each material, the moisture absorption and
excess dimension can be up to 2% of the inner diameter. the thermal expansion are imperative. Plain bearings with
This ensures the secure press-fitting of the bearing. Axial or low moisture absorption can be designed with a minimal
radial movement in the housing are also prevented this way. amount of bearing clearance. For wall thickness, the rule is:
The hole in the housing should be made with the the thicker the bearings are, the larger the tolerances must
recommended tolerance (H7) for all bearings and be be. Thus, different tolerance classes exist for iglidur plain
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smooth, flat and chamfered. The bearing should be press- bearings. Within these tolerances, iglidur plain bearings
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fitted using a flat press. The use of centring or calibrating can operate in the permissible temperature range and in
pins can cause damage to the bearings and bring a greater humidity conditions up to 70% according to the installation
amount of clearance. recommendations. Should higher air moisture levels be
present, or the bearing is used under water, we provide
Adhesion advice with regard to applications, in order to help you use
It is not usually necessary to use an adhesive to fit the Picture 12: The bearing should be press-fitted using your bearings correctly. Picture 13: measurement of the inner diameter of a
bearing. If a bearing is likely to lose its firm fit on account a flat press press-fit plain bearing
of high temperatures, a more temperature-resistant plain Testing methods
bearing should be used. If, however, there are plans to iglidur plain bearings are press-fit bearings for housings
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secure the bearings with adhesive, it will be necessary with a H7 standard hole. This press-fitting of the bearing
to perform suitable tests in each case. It is not possible fixes the bearing in the housing, and the inner diameter of 1
to simply transfer the successful results seen in other the plain bearing is also formed upon press-fit.
applications. The bearing size test is performed when the bearing is
installed in a hole with the minimum specified dimension; 2
both using a dial gauge and a plug gauge:
Machining ● The "Go-Side" of the plug gauge, pressed into the
iglidur plain bearings are delivered ready-to-fit. The hole, must pass easily through the bearing
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extensive product line makes it possible to use a standard ● With the 3 point probe, the inner diameter of the
dimension in most cases. If for some reason, a subsequent bearing must lie within the prescribed tolerance on the 3
machining of the plain bearing is necessary, the adjacent measurement plane (diagram 20)
table shows the machining standard values. The subsequent
machining of the sliding surfaces is to be avoided if possible. Troubleshooting Ø
Higher wear rate is most often the result. In spite of careful manufacturing and assembly of the Diagram 20: Positions of the measurement lines
An exception is iglidur M250 which is suitable for bearings, differences and questions regarding the
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subsequent machining. In other iglidur plain bearings, recommended installation heights and tolerances can
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disadvantages of a sliding surface machining can be result. For this reason, we have compiled a list of the most
counteracted by lubrication during installation. frequent reasons for differences. In many cases, with this
troubleshooter, the reasons for the differences can be found
quickly:
Process Turning Drilling Milling ● The hole is not chamfered correctly, so the bearing
Tool material Stainless steel Stainless steel Stainless steel material is removed upon press-fitting
Feed [mm] 0.1…0.5 0.1…0.5 up to 0.5 ● A centring pin was used which expanded the inside
Clearance angle 5…15 10…12 3 diameter of the bearing during press-fit
Rake angle 0…10 3…5 ● The hole does not meet the recommended housing 20–30°
Cutting speed [m/min] 200…500 50…100 up to 1,000 hole specifications (usually H7)
Table 09: Guidelines for machining ● The housing is made out of a soft material that was
expanded by the bearing installation
● The shaft is not within recommended tolerances Diagram 21: Press-fit of the bearing (section view)
ASEAN 09/2023 ASEAN 09/2023 measuring lines
The measuring doesn't take place within the
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