Bearing Parameterization

Figure 1 shows a generic built-in roller bearing that can be parameterized to get any cylindrical roller bearing. 

Figure 1: Generic cylindirical roller bearing [1]. 

The parameters to model the desired bearing are categorized as follows:

• Catalog parameters
• System parameters
• Other parameters

Below, an SKF NU 306 ECP bearing is used to show how to parameterize the model. 

Note that the library also contains specific examples for the following manufacturers: SKF, NSK, KOYO, TIMKEN, and FAG.

Catalog Parameters

Catalog parameters are found in the bearing catalog from the respective manufacturer, in this case, the SKF Catalog[2].

Figure 2 shows the parameters for the NU 306 ECP bearing. These are the values that should be entered in the Catalog Parameters section of the Bearing Dimensions tab.

For some bearings, the catalog parameters may not be represented as the given configuration above. In such models, it is advised to use CAD files instead.

System Parameters

As shown in Figures 3 and 4, the radial and axial clearances are also listed in the catalog. However, in both cases, ranges are given, as they depend on the installation. Therefore, the chosen values should be set in the System Parameters section of the Bearing Dimensions tab.

Figure 3: Radial internal clearance of cylindrical bearings with a cylindrical bore (such as the NU 306 ECP).

The axial clearances are chosen from the axial internal clearance tables. Below, axial clearances for NUP cylindrical bearings are shown. To model the desired bearing, the corresponding table should be looked at.   

Figure 4: Axial internal clearance for NUP cylindrical roller bearings (such as the NU 306 ECP).

For the axial clearance in the NU 306 ECP, it has been set to 0 since there is no clearance between the outer ring and rollers. This is simply an implementation decision. However, it is recommended to set the radial clearance to -0.001mm in order to make the simulations more robust. Without this setting, the simulations may generate numerous events as they try to determine whether or not contact is occurring.

Other Parameters

The parameters found in the Other Parameters section cannot be easily found in catalogs. Instead, different methods should be used, depending on the specific manufacturer. 

For instance, in this example, a corresponding CAD file can be found on SKF website, see Figure 5.

The roller dimensions, roller number and wall width can be measured from this CAD file. 

References for Roller Bearing Parameter Values

[1]  SKF Group. SKF Catalog, Chapter 6.1. "Single Row Cylindrical Roller Bearings." 2018: 520. https://www.skf.com/binaries/pub12/Images/0901d196802809de-Rolling-bearings---17000_1-EN_tcm_12-121486.pdf.

[2]  SKF Group. SKF Catalog, Chapter 6.1. "Single Row Cylindrical Roller Bearings." 2018: 518. https://www.skf.com/binaries/pub12/Images/0901d196802809de-Rolling-bearings---17000_1-EN_tcm_12-121486.pdf.

[3]  SKF Group. SKF Catalog, Chapter 6.1. "Single Row Cylindrical Roller Bearings." 2018: 508. https://www.skf.com/binaries/pub12/Images/0901d196802809de-Rolling-bearings---17000_1-EN_tcm_12-121486.pdf.