Differential Ring Gear Torque Sensing Without Wheel Strain Gauges
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Solution Overview
Problem
Existing methods for determining wheel torque in vehicles are costly and prone to signal robustness issues due to the need for strain gauges at the wheels, which are not always reliable.
Innovation Solution
Measuring the position of a differential ring gear assembly using a non-contact position sensor to estimate torque delivered to an axle, providing a cost-effective and robust alternative for torque determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If strain gauges are installed at vehicle wheels to measure actual wheel torque, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses the ring gear assembly as an intermediary component to indirectly measure wheel torque. Instead of directly installing sensors on the wheels, the system measures the axial position of the ring gear assembly which correlates to torque conditions, providing a simplified measurement path that avoids complex wheel-mounted sensor installations
Solution Approach 2:
The patent replaces the mechanical strain gauge system with a magnetic field-based position sensing system. The non-contact position sensor uses magnetic fields to detect ring gear assembly position, eliminating the need for mechanical strain gauges and their associated wiring and signal transmission components
2Measurement precision
If strain gauges are installed at vehicle wheels to measure actual wheel torque, then measurement precision is improved, but reliability deteriorates due to signal transmission issues
Solution Approach 1:
The patent replaces the mechanical/electrical strain gauge signal transmission system with a non-contact magnetic field-based position sensing system. This eliminates physical contact and associated signal transmission problems such as wear, interference, and connection failures, significantly improving reliability
Solution Approach 2:
The ring gear assembly serves as a magnetic intermediary that translates torque conditions into detectable position changes. The non-contact position sensor detects changes in the magnetic field caused by ring gear assembly position, providing reliable signal transmission without physical contact
3Measurement precision
If strain gauges are installed at vehicle wheels to measure actual wheel torque, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The non-contact position sensor serves multiple functions: it measures ring gear assembly position, determines wheel torque, and provides data for powertrain control. This multi-functionality eliminates the need for dedicated wheel torque sensors, reducing overall system cost
Solution Approach 2:
The patent employs a cost-effective sensing approach using commercially available non-contact position sensors and magnetic field technology, replacing expensive strain gauge systems. The solution uses inexpensive magnetic materials and simple sensor construction to achieve reliable torque measurement at lower cost
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
This approach simplifies torque determination for powertrains, offers robust signal transmission, and provides powertrain torque feedback at a lower cost compared to traditional methods.
Implementation Method 1
measuring, with the non-contact position sensor, the axial position of the differential ring gear assembly
Data Source
AI summary
Methods and systems for estimating an amount of torque that is transferred via a differential ring gear assembly are described. In one example, axial displacement of the differential ring gear assembly is determined and converted into a torque estimate. The torque estimate may be used to verify other powertrain torque estimates or for closed loop torque control.