Tuned Vibration Based Gear Checker for Gear Profile Anomaly Detection

Significant cost and quality metrics can be realized through the no-faults-forwards approach. This philosophy has put emphasis on early detection of defects through innovative signature analysis techniques within Powertrain Operations production lines. This paper captures the unique approach adopted on gear machining line for functionality testing of individual gears and detection of subtle gear profile anomalies leading to Noise, Vibration and Harshness (NVH) issues in fully assembled transmissions and vehicles. Gears are tested in a Vibration Based Gear Checker (VGC) in single flank engagement and operating under a torque load. The short cycle time enables feasibility for high volume measurements. The structure of Gear Checker is tuned for optimum gear profile anomaly detection**. The tuning is accomplished by structural modifications such that the Gear Checker structural natural frequencies and modes are shifted to enable a high level of excitation at harmonics of Gear Mesh Frequency (GMF) during operation. Impact testing was deployed to guide the structural adjustments for tuning. Gear checker vibration signatures for smooth and defective gears are provided; capability for detection of defective gears is demonstrated. The Gear checker frequency band vibration levels exhibit excellent correlation with the dimensional gear profile measurements by Analytical Gear Checker Coordinate Measuring Machines (CMM’s).