Comprehensive Discussion on the Cooperation and Adjustment Methods of High-Speed Bearings

Source: China Bearing Network | Date: July 17, 2013

High-speed bearings are crucial components in many industrial applications where both speed and temperature can significantly impact performance. As the operating conditions change from normal to high temperatures, there are notable variations in scale, hardness, and material properties. Additionally, at high speeds, centrifugal forces can cause changes in force distribution and shape, which must be carefully considered during design and installation. When selecting the cooperation and clearance for high-speed bearings, it's essential to maintain precision and functionality under extreme conditions. The deformation of the raceway after installation is a critical factor that must be taken into account. The interference fit that works well at normal temperatures may not be effective at high speeds, so careful calculation is required. If the calculated values are too highâ€”especially under ultra-high-speed conditionsâ€”it's recommended to use a combination of under-smoothing and static-pressure lubrication methods. These techniques can help break the 3 million dmn (diameter Ã— speed) barrier, ensuring optimal performance. In addition to these factors, thermal expansion of the shaft must also be considered when determining the bearing clearance. The ideal clearance should be achieved at the working temperature, with accurate alignment between the inner and outer rings. To minimize relative sliding and internal friction, adjusting the axial position of the inner and outer rings is often the best approach for ball bearings. The characteristics of materials used in high-speed bearings also play a significant role. At elevated temperatures, materials tend to soften and deform more easily. Repeated temperature changes can lead to permanent deformation, making it important to select appropriate materials and designs that can withstand such stresses. Furthermore, the mainframe-related parts must meet higher standards of dimensional and geometric accuracy. This includes the coaxiality and straightness of the shaft shoulders relative to the housing or journal. These considerations are especially important when dealing with high-speed and high-temperature environments. The shaft support system needs to be both rigid and lightweight to balance performance requirements. Techniques such as reducing surface roughness, improving surface reinforcement, and using hollow shafts can help achieve this balance. One example of ultra-high-speed bearing development is the HA-type tapered roller bearing. Originally developed for gas turbines, machine tools, and engineering machinery, these bearings address challenges like high-speed operation and large axial loads. Ball bearings often have limited application due to their inability to handle heavy axial loads, while cylindrical roller bearings struggle with axial clearance adjustments. Tapered roller bearings offer a better solution. A key challenge in high-speed tapered roller bearings is managing wear and heat buildup at the contact points between the inner ring ribs and the roller ends. Improving the smoothness of these areas helps reduce friction and prevent damage. In traditional designs, achieving sufficient lubrication in these regions is difficult due to high sliding velocities. To overcome this, Japan and other countries developed the HA-type tapered roller bearing. In this design, the oil flow path is optimized by placing the rib on the outer ring. This allows for better lubrication of the outer ring rim and the roller end face, even when the bearing is stationary. Oil is stored in these areas to prevent burning during startup, while oil drain holes on the outer ring ribs ensure proper oil circulation and prevent excessive power loss and temperature rise. Since the inner ring does not have ribs, the temperature remains lower, reducing the risk of seizure between the inner ring and the shaft. The outer ring-guided frame ensures smooth operation of the rollers without tilting, which minimizes wear and improves high-speed performance. HA-type bearings can achieve a dmn value of up to 2 million, which represents a significant improvement over conventional designs. For example, in a gas turbine reducer spindle (model I-IA30205), under a load of 1000N, a 2L/min oil supply of No. 4 turbine oil allows the bearing to operate at 60,000 RPM without experiencing overheating or damage. --- **Related Bearing Knowledge:** - Key skills in bearing production - Detailed function of LYC deep groove ball bearings - Koyo bearing cracking and failure prevention - Disassembly method for Beijing 130 automotive shaft guide bearings - Common issues in sliding bearings This article was originally published on [China Bearing Network](http://). For more information, visit [Bearing Network](http://). Previous: Basic Functional Requirements of Rolling Bearings for Data Next: Brief Analysis of Causes and Cleaning Methods of Fan Bearings
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