Torque Sensor Friction Coupling Eliminates Adhesive Hysteresis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing torque sensors using strain gauges on rotating elements face issues with precision loss due to adhesive materials, hysteresis errors, and susceptibility to environmental degradation and damage from aggressive chemicals and friction.
Innovation Solution
A torque sensor design featuring strain gauges on an adhesive material layer with a rigid substrate and detachable, adjustable pressure means that provide frictional retention without adhesives, protecting the gauges from wear and environmental attacks while allowing for easy replacement and optimal friction adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If adhesive material is used to attach strain gauges to the rotating element, then the strain gauges can be securely fixed, but measurement precision deteriorates due to hysteresis errors and non-linear deformation of the adhesive
Solution Approach 1:
The patent removes the adhesive material layer from between the strain gauges and the rotating element. Instead, the strain gauges are attached directly to the rotating element surface, eliminating the source of hysteresis errors and non-linear deformation that degraded measurement precision.
Solution Approach 2:
The patent introduces a retention mechanism that uses frictional forces as an intermediary to secure the strain gauges without adhesive. The retention mechanism applies normal force to press the strain gauges against the rotating element surface, creating sufficient friction to prevent detachment while maintaining direct contact for accurate measurement.
2Measurement precision
If strain gauges are pressed directly onto the rotating element to avoid adhesive, then hysteresis errors are eliminated, but the strain gauges become vulnerable to damage from friction and aggressive environmental chemicals
Solution Approach 1:
The retention mechanism acts as an intermediary protective layer between the strain gauges and the harsh environment. It provides the necessary frictional retention while the strain gauges remain in direct contact with the rotating element for measurement, but the retention mechanism can be designed to protect against chemical exposure.
Solution Approach 2:
The retention mechanism can be implemented as a thin protective film or shell that covers the strain gauges, protecting them from aggressive chemicals and friction while allowing the necessary mechanical contact for torque measurement through the thin protective layer.
3Ease of manufacture
If adhesive material is used to attach strain gauges, then the assembly is simple, but the adhesive degrades over time causing loss of elasticity and measurement effectiveness
Solution Approach 1:
The patent eliminates the adhesive material layer entirely, removing the component that degrades over time. The strain gauges are secured through direct frictional contact or a retention mechanism that does not rely on chemical bonding, thereby eliminating the aging and degradation issues associated with adhesive materials.
Solution Approach 2:
The retention mechanism is designed to be replaceable and durable, allowing the strain gauge assembly to be easily replaced if needed, while the retention mechanism itself can be made from durable materials that do not degrade like chemical adhesives.
4Measurement precision
If strain gauges are in direct contact with the rotating element for friction-based measurement, then adhesive-related hysteresis is eliminated, but the strain gauges are exposed to aggressive transmission oils and chemicals that accelerate aging
Solution Approach 1:
The retention mechanism serves as a protective intermediary between the strain gauges and the harsh chemical environment. It allows the strain gauges to maintain direct contact with the rotating element for accurate friction-based measurement while protecting them from exposure to aggressive transmission oils and chemicals that would otherwise accelerate aging and degradation.
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 design enhances the durability and accuracy of torque measurements by preventing hysteresis errors, reducing environmental impact, and extending the lifespan of the sensor while maintaining performance over time.
Implementation Method 1
the adhesive material layer rests on a face of a substrate made of a rigid material capable of ensuring frictional retention against the rotating element via its face that is opposite that supporting the adhesive material layer
Data Source
AI summary
A torque sensor intended to be mounted on a rotating element in a motor vehicle, the torque sensor including at least one strain gauge disposed on an adhesive material layer. The glass layer rests on a face of a substrate made of a rigid material capable of ensuring frictional retention against the rotating element by its face that is opposite that supporting the glass layer, the torque sensor including detachable and adjustable pressure device surrounding the glass layer and the substrate, the detachable and adjustable pressure device being intended to surround the rotating element and to press the face opposite the substrate against the rotating element.