Torque Sensor Integrating Angular Position via Shared PCB Windings
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Solution Overview
Problem
Existing torque sensors in motor vehicles face challenges in combining angular-position measurement with torque measurement due to size and cost constraints, as they require separate sensors that are difficult to integrate without increasing size or interfering with each other's signals.
Innovation Solution
A torque sensor design that incorporates a strain gauge on an adhesive material layer with a moving part and a fixed printed circuit board, where the printed circuit board is redesigned to dedicate regions for both torque and angular-position measurement, using annular sectors with secondary and primary windings to avoid signal interference and share common elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate torque sensor and angular-position sensor are used, then measurement functions are complete, but device size and cost increase
Solution Approach 1:
The patent combines a torque sensor and an angular-position sensor into a single integrated device. The torque sensor includes strain gauges mounted on a shaft, while the angular-position sensor uses a magnet mounted on the same shaft detected by a Hall effect sensor. This merging allows both torque and angular position measurements to be performed simultaneously using shared mechanical components (shaft, magnet), thereby reducing overall device size and cost while maintaining complete measurement functionality.
Solution Approach 2:
The shaft serves multiple functions: it is both the mechanical element being measured for torque (via strain gauges) and the rotating element whose angular position is measured (via the mounted magnet and Hall effect sensor). This multi-functionality eliminates the need for separate sensing systems, reducing the overall sensor package size and component count.
2Adaptability or versatility
If separate torque sensor and angular-position sensor are used, then measurement functions are complete, but manufacturing cost increases
Solution Approach 1:
The patent merges two separate sensing functions into one device, reducing the total number of components that need to be manufactured and assembled. The shared shaft and magnet reduce part count, while the compact integration reduces assembly complexity, thereby lowering manufacturing costs despite maintaining complete measurement functionality.
Solution Approach 2:
The shaft performs dual roles as both the torque measurement substrate and the angular position reference, eliminating the need for separate mechanical components for each function. This universality reduces material costs, manufacturing steps, and assembly operations, making the integrated sensor more cost-effective than separate sensors.
3Volume of moving object
If torque sensor and angular-position sensor are integrated, then device size is reduced, but signal interference may occur
Solution Approach 1:
The patent introduces magnetic field shielding as an intermediary element between the Hall effect sensor and the magnet. This shielding prevents direct magnetic field interference with the strain gauge measurements while allowing the Hall effect sensor to detect the magnet's position. The shield acts as a selective barrier that permits necessary magnetic field interaction for angular position detection while blocking harmful interference with torque measurement signals.
Solution Approach 2:
The patent extracts the magnetic field interaction function into a separate angular-position sensing subsystem using the Hall effect sensor and magnet, distinct from the strain gauge-based torque measurement. This separation of measurement principles (mechanical strain vs. magnetic field detection) within the integrated device allows both functions to operate simultaneously with minimal mutual interference, as they use different physical domains for sensing.
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 allows for a compact, cost-effective sensor that simultaneously measures torque and angular position without increasing size, leveraging shared elements and minimizing additional costs by using existing components and machining processes.
Implementation Method 1
at least one strain gauge applied to an adhesive material layer, said at least one strain gauge emitting an electrical signal as a function of the torsion experienced by the rotating element
Implementation Method 2
at least one annular primary emitter winding designed to induce an electrical voltage in said secondary receiver windings
Implementation Method 3
at least a first annular secondary receiver winding designed to generate a sine signal as a target passes past it, at least a second secondary receiver winding designed to generate a cosine signal as a target passes past it
Data Source
AI summary
A torque sensor mounted on a rotating element in a motor vehicle, including at least one strain gauge and emitting an electrical signal as a function of the torsion experienced by the rotating element, the torque sensor having a moving part intended to be driven in rotation with the rotating element and including the strain gauge and a fixed part including a first printed circuit board. The torque sensor also acts as an angular-position sensor, the moving part bearing angularly distributed targets passing in succession past a first annular sector borne by the first board including a secondary receiver winding generating a sine signal, a secondary receiver winding generating a cosine signal, and a primary emitter winding inducing a voltage in the receiver windings.