Fastening Methods
Due to their compact structural form, the three main bearing types can be configured within a modular system with integrated assembly holes. AXDR double row angular contact roller bearings are particularly easy to assemble.
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Standard Fastening Design
The drilling pattern and counterbore design shown correspond to the most common variants:
| Code | Design Name | Description |
|---|---|---|
| SA | Counterbores opposite | Counterbores of the inner and outer rings are on opposite sides |
| SS | Counterbores identical | Counterbores of the inner and outer rings are on the same side |
Other variants: Variants with through holes or threaded holes are available on request.
Construction Height/Clearance
The individual ring is always unsupported on the cylindrical counterbore side by a counterbore depth of 0.2 mm, which means that the possibility of collision is excluded in fastening method "SA".
On the other hand, if ring arrangement "SS" is selected, the total height is reduced by 0.2 mm because both recessed cylindrical counterbores are located on the same side.
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Seals
Double row angular contact roller bearings are equipped with non-rubbing gap seals. These seals seal reliably in normal environments without increasing the friction torque.
Optional Seal Types
- NBR seals - increase the sealing effect but generate additional friction at the seal contact surface
- Viton seals - resistant to high temperatures and chemicals
For oil or oil/air lubrication, the seals can be adapted for controlled feed/discharge or distribution of the lubricant in the bearing.
Accuracy Grades
AXDR bearings are supplied in the standard series with dimensional tolerance P5 acc. DIN 620. The highly accurate bore and outer diameter designs permit the production of accurate fits and guides, which is a great advantage in machine tools.
| Accuracy Grade | Description |
|---|---|
| Standard | P5 acc. DIN 620 dimensional tolerance |
| PRR50 | Restricted running accuracy (axial and radial runout tolerances constricted) |
Running tolerances (axial and radial runout) are available in two grades: Standard and Restricted (PRR50). These accord approximately with tolerances P2 and UP.
Other Tolerance Restrictions
Other tolerance restrictions can be provided on request. For example, height tolerance and offset tolerance can be defined in the same way as precise running torque.
Lubrication/Corrosion Protection
The initial filling uses a high-performance grease from a Li-special soap base mixed with synthetic hydrocarbon oil and mineral oil.
The grease is a special low-noise running grease with additives suitable for the operation of cylindrical roller bearings. Most conventional greases are not suitable for the operation of double row angular contact roller bearings and generate excessively high friction, especially at higher speeds.
Avoid Overfilling
Overfilling of the bearing must be avoided. Excessively high grease quantities generate higher levels of friction heat, which must be limited during initial operation and subsequent re-lubrication.
We recommend oil lubrication for high-speed applications. Our engineering team will be happy to assist with further details and possible limit speeds.
Re-lubrication
Re-lubrication takes place radially via several lubrication channels in the outer ring. The position of the lubrication channels in the inner ring's channels is listed under "Positioning Hole" in the product data sheet.
The bearings are supplied only with corrosion protection oil and marked with the suffix L120. Fuchs Anticorit DF 19 is used as the corrosion protection oil. This can be easily removed with most oils and greases.
Surface Treatment
myonic double row angular contact roller bearings are offered in the standard series without surface treatment.
Measuring System
AXDR bearings cannot be equipped with a mounted measuring system.
For applications requiring measuring systems, we recommend bearings from the AXRY-EX or AXRY-ES series, which are available with incremental and absolute angle measuring systems.
Dimensions/Fixing Holes
All main dimensions such as bore diameter, outside diameter, bearing height, and fixing screws are identical to those of other manufacturers.
myonic AXDR double row angular contact roller bearings have further restricted standard tolerances to ensure raceway alignment and define standards.
The main dimensions and fixing holes represent the most common sizes and define the standard. If required, our application engineers are happy to provide further dimensions.
Rigidity Calculation
The rigidity calculation is performed under the following parameters:
- Radial and axial loads as well as tilting torque applied under axial preload conditions
- Light preload
- Normal adjacent construction and screw connection acc. to the information in the production chapter
- The same FEM calculation procedure used across all product groups with the previously defined parameters
Rigidity Value Notes
The rigidity values listed in the product tables can be directly compared (AXRY vs. AXDR vs. AXCR). An under-dimensioned, inaccurate adjacent construction reduces the rigidity at the bearing position, whereas on the other hand rigidity can be increased through constructional support. Our engineering team will be happy to assist with further details or shaft optimization.
Limit Speed/Bearing Friction Torque
Limit Speed
The limit speeds shown in the dimension tables can be achieved under the following conditions: short-term continuous operation or swivel operation. If operating in the limit speed range for extended periods, a cooling system should dissipate any friction heat generated by the bearing.
We recommend oil lubrication for high-speed applications. Our engineering team will be happy to assist with further details and possible limit speeds.
Friction Torque
The friction torque of double row angular contact roller bearings is influenced in particular by the selected preload. Higher preload results in higher rigidity but at the same time generates higher levels of friction.
The selected lubricant (in particular the viscosity) and the filling quantity also have a direct influence on friction. Standard pre-greased bearings are suitable for short-term operation and short-term continuous operation up to the limit speed.
Metering Systems Are Most Suitable
Metering systems are most suitable for re-lubrication purposes. In the case of manual re-lubrication, there is a risk of overfilling, thereby increasing the bearing friction torque.
During operation or re-lubrication, appropriate run-in cycles must be adhered to. The specifications for the adjacent construction and surrounding parts must be observed.
Axial and Radial Runout
The undivided individual rings favor maximum radial runout and running accuracy. The narrow standard tolerances can be further constricted (suffix "PRR50").
myonic radial runout values include the radial runout error of the raceway and the roundness of the bore.