Electric Axle Drivetrain Wear Detection via Rotor Angle Feedback
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Solution Overview
Problem
Existing electric axle drive trains lack the ability to accurately determine and evaluate vehicle-specific wear scenarios during operation, leading to potential mechanical and electrical wear issues.
Innovation Solution
An electric axle drive train system that includes a control unit to monitor mechanical wear by using a rotational angle sensor and a rotation blocking device, applying controlled torque in specific directions to analyze the rotor's rotational angle and current strength, correlating these values to form an actual wear characteristic curve, and comparing it with a target curve to detect deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional electric axle drive trains are used without wear monitoring systems, then the device complexity is reduced, but the ability to detect and evaluate mechanical wear is insufficient
Solution Approach 1:
The patent implements a feedback mechanism where the control unit continuously monitors the rotational angle sensor signals and compares actual wear characteristics against target wear characteristics. This closed-loop feedback enables precise wear detection by analyzing deviations between expected and actual component behavior, directly addressing the need for improved measurement precision while justifying the added system complexity through enhanced diagnostic capability
Solution Approach 2:
The wear monitoring system utilizes existing components (rotational angle sensor, control unit, and normal operating torques) to perform self-diagnosis of mechanical wear. By analyzing data already generated during normal vehicle operation, the system enables wear detection without requiring separate dedicated measurement devices, thereby improving measurement precision while minimizing the increase in device complexity
2Reliability
If a rotation blocking device and rotational angle sensor are added to monitor wear, then wear detection capability is improved, but the device complexity increases
Solution Approach 1:
The control unit is designed to perform multiple functions: it controls the electric machine for propulsion, manages the rotation blocking device for wear analysis, processes rotational angle sensor signals, and generates wear diagnostics. By making the control unit multi-functional, the patent improves reliability through comprehensive monitoring while avoiding the need for separate dedicated monitoring hardware, thus limiting the increase in device complexity
Solution Approach 2:
The rotational angle sensor serves as an intermediary component that provides rotational position data used both for normal control operations and for wear analysis. This intermediary approach allows the system to extract wear information from existing operational data without requiring direct physical contact or additional specialized sensors, thereby improving reliability while keeping the monitoring system relatively simple
3Measurement precision
If wear analysis requires blocking rotation and applying controlled torque, then measurement precision is improved, but the productivity of the vehicle operation is reduced
Solution Approach 1:
The wear analysis is performed periodically during normal vehicle operation by utilizing existing acceleration and deceleration phases. The control unit identifies suitable moments when the vehicle is naturally accelerating or decelerating, blocks rotation briefly, applies controlled torque, and analyzes the rotational angle sensor signals. This periodic approach enables precise wear measurement while minimizing disruption to overall vehicle productivity, as the actual measurement duration is very short and occurs during routine operational transitions
Solution Approach 2:
The system prepares for wear analysis by pre-identifying suitable operational conditions (acceleration or deceleration phases) and having the rotation blocking device and torque control ready. When conditions are appropriate, the system quickly executes the measurement sequence. This preliminary preparation enables high-precision wear measurement to be performed efficiently during brief windows of opportunity without significantly impacting vehicle productivity
Data Source
AI summary
The disclosure relates to an electric axle drive train of a motor vehicle. The drive train includes an electric machine having a rotor which is mounted rotatably relative to a stator and can be supplied with current by a control unit, a gear assembly which is coupled to the rotor and a first rotatably mounted output shaft which is operatively connected to the gear assembly in a torque-transmitting manner. The output shaft is connected in a torque-transmitting manner to a vehicle wheel of the motor vehicle. An actuatable rotation blocking device is positioned between the rotor and the vehicle wheel in such a way that a rotation of shafts lying in a torque flux can be blocked. At least one rotational angle sensor is positioned between the rotor and the rotation blocking device in such a way that it provides a signal, that represents a rotational angle position, to a shaft lying in said torque flux.