Torque and Angular Sensor Using Differential Inductive Coupling
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Solution Overview
Problem
Existing torque and angular sensors in Electrical Power Steering systems require multiple inductive elements and complex logic, leading to inefficiencies and reduced accuracy in measuring torque and angular movements of torsion elements.
Innovation Solution
A torque angle sensor design that uses fewer inductive elements, with a differential angle sensor determining the torque angle by monitoring electrical characteristics of coils adjacent to rotating targets with teeth, and a processor calculating the rotation angles over specific ranges to provide accurate measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple inductive elements are used in the sensor, then the measurement coverage is improved, but the device complexity and number of components increases
Solution Approach 1:
Each inductive element is configured to perform multiple functions: detecting both the first rotation angle of the input shaft and the second rotation angle of the output shaft through different coupling arrangements. This eliminates the need for separate dedicated sensors for each measurement task, reducing overall component count while maintaining comprehensive measurement capability
Solution Approach 2:
The patent changes the coupling parameters between inductive elements and rotating members by using different numbers of teeth (e.g., first number of teeth for input shaft coupling, second number of teeth for output shaft coupling). This allows a single inductive element to distinguish between different rotation sources through parameter differentiation rather than requiring separate physical sensors
2Measurement precision
If multiple inductive elements and complex logic are used, then angular sensing capability is improved, but the reliability decreases due to more potential failure points
Solution Approach 1:
The inductive elements are designed with multi-functional coupling capabilities, where each element can detect rotation from either the input shaft or output shaft depending on its specific configuration. This reduces the total number of inductive elements required, thereby reducing potential failure points while maintaining comprehensive angular sensing capability through proper signal processing logic
3Measurement precision
If more inductive elements are deployed, then the accuracy of torque angle measurement is improved, but the manufacturing cost and complexity increases
Solution Approach 1:
The sensor design employs inductive elements that serve multiple measurement purposes simultaneously. Each element is configured with specific tooth couplings that enable it to contribute to both input shaft angle detection and output shaft angle detection, reducing the total component count and simplifying manufacturing assembly processes while maintaining measurement accuracy
Solution Approach 2:
The patent merges the functionality of multiple dedicated sensors into a unified inductive element system. By combining the detection capabilities for both input and output shaft rotations into fewer multi-coupled elements, the design simplifies manufacturing operations and reduces assembly complexity while preserving the accuracy needed for precise torque angle measurement
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enhances accuracy and reliability by reducing the number of inductive elements, allowing for more compact designs and improved vehicle operation through precise torque and angular measurements.
Implementation Method 1
an output coil disposed adjacent to the output target and inductively coupled with at least one of the output teeth
Implementation Method 2
an input coil disposed adjacent to the input target and inductively coupled with at least one of the input teeth
Data Source
AI summary
A torque and angular sensor includes a differential angle sensor to precisely measure a differential angle between an input shaft and an output shaft and an angular position sensor to measure the angle of at least one of the shafts over a full angular range. The differential angle sensor measures an output rotation angle of an output target and an input rotation angle of an input target using changing voltages in taps on the input and output coils, which each carry an AC excitation current and which are each inductively coupled with teeth on targets fixed to rotate with one of the shafts. Input shaft rotation angle region is combined with the input angular position as a rotation angle composite. A raw torque angle is determined based on the difference between the input and output rotation angles. Rotational and Linear compensation provides a high-precision torque angle.