What is a Thrust Bearing?
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Thrust bearings generally consist of two or more thrust washers and several rolling elements. Thrust bearings are also known as axial bearings. The following is an introduction to thrust bearings: 1. Thrust ball bearings: Thrust ball bearings are a type of separable bearing where the shaft washer, housing washer, cage, and ball assembly can be separated. The shaft washer is the ring that fits with the shaft, while the housing washer is the ring that fits with the bearing housing bore and has a clearance with the shaft. Thrust ball bearings can only withstand axial loads. Single-direction thrust ball bearings can only withstand axial loads in one direction, while double-direction thrust ball bearings can withstand axial loads in both directions. Thrust ball bearings cannot limit radial displacement of the shaft and have a very low speed limit. Single-direction thrust ball bearings can limit axial displacement of the shaft and housing in one direction, while double-direction bearings can limit axial displacement in both directions. 2. Thrust roller bearings: Thrust roller bearings are used to primarily withstand axial loads combined with radial loads, but the radial load must not exceed 55% of the axial load. Compared to other thrust roller bearings, this type has a lower friction coefficient, higher speed, and self-aligning capabilities. The 29000 series bearings feature asymmetric spherical rollers, which reduce relative sliding between the rollers and raceways during operation. These rollers are long, large in diameter, and numerous, offering high load capacity. They are typically lubricated with oil, though grease lubrication can be used in some low-speed applications. In design selection, priority should be given to these bearings. The 80000 series thrust cylindrical roller bearings, 90000 thrust tapered roller bearings, and AXK-type thrust needle roller bearings can withstand unidirectional axial loads. They have much higher axial load capacity than thrust ball bearings, greater rigidity, and occupy less axial space. Thrust cylindrical roller bearings and thrust needle roller bearings are suitable for low-speed applications, while thrust tapered roller bearings can operate at slightly higher speeds than thrust cylindrical roller bearings. 3. Thrust needle roller bearings: Thrust needle roller bearings can be considered a special type of thrust cylindrical roller bearing, where the length-to-diameter ratio (defined as the ratio of roller length to diameter) is significantly greater than 2. Therefore, the load capacity of thrust needle roller bearings is significantly lower than that of thrust cylindrical roller bearings of equivalent diameter. Thrust needle roller bearings are used in medium to low-speed ranges to prevent the adverse effects of sliding between the rollers and raceways. Thrust needle roller bearings can be complete bearing assemblies with thrust washers and roller cage components or simply needle and cage assemblies. The needles are hardened and precision-ground to ensure optimal load distribution.