Thrust bearings are designed primarily to carry loads acting along the shaft axis. Depending on their rolling element and raceway design, they can support axial loads in one or both directions. Some roller thrust bearings can also accommodate a certain amount of radial load. Thrust ball bearings are mainly used for pure axial loads, while spherical roller thrust bearings offer higher axial load capacity and can also carry limited radial loads.
Load characteristics of thrust ball bearings
Thrust ball bearings are designed primarily for axial loads. They are available in single-direction and double-direction designs.
Single-direction thrust ball bearings can accommodate axial loads in one direction only. They are suitable for applications where the direction of the axial force remains fixed. Double-direction thrust ball bearings can carry axial loads in both directions and are used in shaft arrangements that require axial positioning in either direction.
These bearings cannot accommodate radial loads and cannot replace radial bearings for radial shaft support. They are therefore normally used together with radial bearings in a complete shaft arrangement.
Thrust ball bearings also have lower limiting speeds than conventional radial bearings of comparable size. Their permissible operating speed must be checked against the actual application requirements.
Load characteristics of thrust roller bearings
Thrust roller bearings are used in transmission systems subjected to relatively high axial loads. Among them, spherical roller thrust bearings in the 29000 series can accommodate axial loads together with a certain amount of radial load. The radial load must not exceed 55% of the axial load.
Compared with some other thrust roller bearing designs, these bearings have a lower coefficient of friction and relatively higher speed capability. They also have a self-aligning function that allows them to accommodate a certain degree of shaft misalignment.
The 29000 series uses asymmetrical spherical rollers. The rollers are relatively long and large in diameter, with a higher number of rolling elements. This design provides high load capacity and reduces relative sliding between the rollers and raceways during operation.
Oil lubrication is normally used. Grease lubrication may also be suitable in some low-speed applications.
Although the 29000 series offers better speed performance than some other thrust roller bearing designs, it should not automatically be classified as a high-speed bearing. The permissible operating speed must be checked against the specifications of the selected model.
Other common types of thrust roller bearings
When axial loads are too high for thrust ball bearings, thrust cylindrical roller bearings, thrust tapered roller bearings, and thrust needle roller bearings can be considered. Common designations include the 80000 series, 90000 series, and AXK series.
These roller thrust bearings are primarily designed for axial loads acting in one direction. Compared with thrust ball bearings, they generally offer higher axial load capacity and greater rigidity.
80000 series thrust cylindrical roller bearings
Thrust cylindrical roller bearings use cylindrical rollers and are designed primarily for axial loads in one direction. They provide high axial load capacity and rigidity but cannot accommodate radial loads and have no self-aligning capability. They are generally used in low-speed applications with heavy axial loads.
90000 series thrust tapered roller bearings
Thrust tapered roller bearings use tapered rolling elements to carry axial loads. They provide high axial load capacity. Their permissible speed is generally slightly higher than that of 80000 series thrust cylindrical roller bearings, although the actual limit depends on the bearing model and lubrication conditions.
AXK series thrust needle roller bearings
AXK thrust needle roller bearings use numerous slender needle rollers. They provide high rigidity and load capacity within a small axial installation space and are designed primarily for axial loads in one direction. Their design makes them suitable for low-speed applications.
Factors to consider when selecting thrust bearings
Thrust bearing selection should be based on the magnitude and direction of the axial load, the presence of radial loads, operating speed, and available installation space.
Thrust ball bearings can be considered for applications with relatively light axial loads and no radial loads. When axial loads are higher, thrust cylindrical roller bearings, thrust tapered roller bearings, or thrust needle roller bearings may be more suitable, depending on speed and installation requirements.
For applications involving high axial loads combined with a certain amount of radial load, especially where shaft misalignment must be accommodated, spherical roller thrust bearings in the 29000 series can be considered.
Different thrust bearing designs have different load capacities, speed limits, and installation requirements. Final selection should be checked against the manufacturer's bearing catalog and the actual operating conditions.
Custom machining of precision components for thrust bearing applications
The installation of thrust bearings and their integration into transmission systems also involve dimensional and fitting requirements for bearing housings, thrust discs, sleeves, and related connecting components. For non-standard parts that cannot be met by standard components, we provide precision machining based on customer-supplied drawings. Both single-piece and small-batch orders are supported.
Hansheng Automation machines bearing support components, shafts, and other non-standard mechanical parts according to customer drawings. Our machining services also cover precision components for yacht equipment and RC racing cars, as well as parts for tobacco packaging and filling machinery. Components are manufactured according to the design requirements of each application.
