This paper systematically summarizes the research status and key progress of skidding issues in high-speed rolling bearings. By combining dynamic theories and experimental methods, it provides important references for solving bearing failures under extreme working conditions such as those in aero-engines. The following are the core contents and innovations of this research:

1. Skidding Mechanism and Failure Hazards

1.1 Definition and Nature of Skidding

When high-speed rolling bearings are under light load or insufficient lubrication, the traction force between rolling elements and raceways cannot overcome resistances (e.g., lubricant viscous force, cage inertial force). This causes the rotational speed of rolling elements to be lower than the theoretical value, resulting in macroscopic sliding. Frictional heat generated by skidding damages the oil film, leading to raceway scratches, wear, or even burning. Skidding accounts for 36.93% of bearing failure cases in aero-engines.

1.2 Typical Failure Modes

• Gyro Sliding: In ball bearings, the imbalance between gyro moment and contact friction moment causes sliding perpendicular to the rolling direction.
• Drag Sliding: Under high-speed and light-load conditions, centrifugal force reduces the contact load of the inner ring, leading to axial sliding of rolling elements dragged by the cage.
• Instantaneous Sliding: Sudden changes in contact load under combined loads or variable-speed conditions trigger instantaneous impact sliding.

2. Development of Dynamic Theoretical Models

2.1 Foundational Foreign Research

• GUPTA Model: Proposed in 1979 for the dynamic analysis of ball bearings and cylindrical roller bearings, it introduces the elastohydrodynamic lubrication (EHL) traction coefficient and develops the ADORE program to simulate skidding behavior under complex working conditions.
• SEPDYN Software: Simplifies motion equations using a polar coordinate system to shorten calculation time, making it suitable for engineering applications.

2.2 Breakthroughs in Domestic Research

• Thermo-Elastohydrodynamic Coupling Model: Shi Xiujiang et al. established a thermo-EHL model considering thermal effects and non-Newtonian fluids, enabling iterative solution of dynamic and lubrication analyses and improving the prediction accuracy of dynamic performance for aero-engine spindle bearings.
• Thermo-Fluid-Solid Coupling Model: Gao Shuai et al. constructed a five-layer cyclic structure model, coupling temperature field, flow field, and solid deformation to simulate the thermoelastic behavior of angular contact ball bearings at high speeds.
• Nonlinear Dynamic Model: Tu Wenbing et al. used springs to simulate collisions between rolling elements and the cage, revealing the influence of nonlinear factors (e.g., radial clearance, cage clearance) on skidding.

2.3 Limitations of Existing Models

Current models generally ignore the coupling between the bearing temperature field and internal flow field. Additionally, traction coefficients mostly adopt simplified curves, limiting the skidding prediction accuracy under high-speed conditions.

3. Experimental Methods and Monitoring Technologies

3.1 Skidding Rate Measurement

• Capacitive Sensor Method: Lugs are installed on the cage side beams. The actual rotational speed of the cage is calculated through the periodic change of capacitive signals, and the skidding rate is derived by comparing it with the theoretical speed.
• Multi-Sensor Fusion: Combines eddy current displacement sensors and vibration acceleration sensors to real-time monitor bearing vibration and displacement, assisting in judging the skidding state.

3.2 Innovations in Test Rig Design

• Multi-Parameter Adjustable System: A test rig developed by Xi'an Jiaotong University can simulate variable speeds (0-30000 r/min), variable loads (axial/radial 10 kN), and variable lubrication (oil temperature 0-200 °C), supporting research on coupled skidding of multiple bearings.
• Critical Speed Matching: Adjusts the modal parameters of the test rig by changing the support stiffness to align its dynamic characteristics with real high-speed machinery.

4. Analysis of Key Influencing Factors

4.1 Operating Parameters

• Speed and Load: Higher speed increases centrifugal force, reducing the inner ring contact load and raising skidding risk. Radial load can suppress skidding by increasing contact stress, but the effect weakens beyond a critical value.
• Lubrication Conditions: Higher lubricating oil viscosity increases viscous resistance, but excessively high viscosity intensifies oil churning power consumption. Under-race lubrication is preferred for its good cooling effect and low oil consumption.

4.2 Structural Parameters

• Radial Clearance: Excessive clearance causes uneven load distribution, while insufficient clearance increases the risk of thermal expansion. Optimization is required to balance these effects.
• Cage Material: Lightweight materials (e.g., tin-phosphorus bronze) reduce inertial force and minimize skidding-induced impact.

5. Skidding Suppression and Prevention Measures

5.1 Design Optimization

• Preload Matching: Based on the Hirano criterion, axial preload compensates for centrifugal force to prevent gyro sliding in ball bearings. For example, 7000C angular contact ball bearings can completely avoid skidding under a radial load of 2000 N and a speed range of 20000-70000 r/min.
• Non-Circular Roller Design: Pratt & Whitney's JT series aero-engines adopt elliptical roller bearings to suppress light-load skidding through additional loads.

5.2 Lubrication Improvement

• Oil-Air Lubrication: Replaces traditional jet lubrication to reduce oil churning loss and improve heat dissipation efficiency.
• Lubricant Modification: Adding nanoparticles or extreme pressure additives enhances oil film load-carrying capacity and anti-wear performance.

5.3 Monitoring and Control

• Real-Time Monitoring Device: Develops a skidding rate monitoring system based on sensors, combined with neural network algorithms to achieve early warning.
• Active Preload Technology: Dynamically adjusts preload through an electro-hydraulic servo system to adapt to variable working conditions.

6. Future Research Directions

6.1 Deepening Theoretical Models

• Establish a multi-physics coupling model integrating thermo-EHL, temperature field, and structural deformation to improve prediction accuracy under high-speed and light-load conditions.
• Develop simplified engineering prediction methods to reduce reliance on complex parameter inputs.

6.2 Innovating Experimental Technologies

• Research visualization technologies for lubricating oil distribution in bearing cavities to reveal the mechanism of oil film rupture and regeneration.
• Combine digital twin technology to build a virtual test platform for simulating skidding behavior under extreme conditions.

6.3 Breakthroughs in Materials and Processes

• Explore new materials such as ceramic bearings and coating technologies to improve anti-skidding and wear-resistant performance.
• Optimize cage manufacturing processes (e.g., using hollow rollers or carbon fiber-reinforced materials) to reduce mass and inertial force.

7. Industrial Applications and Cases

7.1 Aero-Engines

Rolls-Royce successfully eliminated skidding faults in intermediate bearings of RB211 engines by changing the cage positioning from the outer ring to the inner ring and optimizing balance.

7.2 High-Speed Machine Tool Spindles

A domestic enterprise optimized the design of angular contact ball bearings using a thermo-fluid-solid coupling model, increasing the spindle's maximum speed to 80000 r/min and reducing the skidding rate by 40%.

7.3 New Energy Vehicle Motors

The drive motor bearings of a certain vehicle model, through increasing radial clearance (0.045-0.065 mm) and improving oil-air lubrication, achieved 5000 hours of skid-free operation at 15000 r/min.

8. Conclusion

This research systematically integrates theories, experiments, and engineering solutions for skidding issues in high-speed rolling bearings, providing a scientific basis for improving the reliability of key equipment in aerospace, high-end manufacturing, and other fields. Future efforts should focus on breakthroughs in multi-physics coupling modeling, intelligent monitoring, and new material applications to address the challenges of higher speeds and more complex working conditions.