Elastically Deformed Wiper Neck for Fuel Level Sensor Contact
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Solution Overview
Problem
Existing fluid-level sensors in automotive fuel tanks face challenges in accurately measuring fuel levels due to unreliable contact between the wiper and conductive traces, leading to inconsistent resistance readings and potential operational failures.
Innovation Solution
A fluid-level sensor design featuring a wiper assembly with an arm pivotally connected to a housing, a float, and an elongate neck with a head that elastically deforms to maintain forceful contact with conductive traces on a ceramic card, ensuring consistent electrical resistance changes as the float moves with the fuel level, thereby providing reliable fuel-level readings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a wiper assembly is used to contact conductive traces, then fuel-level readings can be obtained, but unreliable contact between the wiper and traces occurs leading to inconsistent resistance readings
Solution Approach 1:
The patent changes the physical state and mechanical properties of the wiper assembly by introducing an elastically deformable neck portion. This allows the wiper head to dynamically adjust its contact force with the conductive traces, ensuring consistent electrical contact. The elastic deformation capability transforms a rigid structure into a flexible one that can maintain reliable contact despite variations in assembly tolerances, trace positioning, or fuel tank movements.
2Reliability
If the wiper maintains forceful contact with the traces, then reliable electrical contact is achieved, but increased mechanical stress may cause operational failures
Solution Approach 1:
The patent introduces dynamic characteristics to the wiper assembly through the elastically deformable neck. Instead of a fixed rigid connection, the neck can dynamically adjust its deformation based on contact conditions. This dynamic flexibility allows the system to maintain sufficient contact force for reliable electrical connection while absorbing mechanical stresses that would otherwise be transmitted directly to the trace connections, thereby preventing operational failures.
3Ease of manufacture
If the wiper assembly structure is simplified, then manufacturing cost is reduced, but contact reliability between wiper and traces deteriorates
Solution Approach 1:
The patent employs a flexible neck portion that acts as an elastic element between the wiper head and the arm. This flexible component is relatively simple to manufacture using common materials and processes, yet it provides the necessary contact force and reliability. The elastic neck can be formed from spring steel or similar materials using standard forming techniques, maintaining manufacturing simplicity while dramatically improving contact reliability compared to rigid alternatives.
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 ensures robust and reliable fuel-level measurements by maintaining consistent contact between the wiper and conductive traces, reducing the risk of operational failures and improving the accuracy of fuel-level readings.
Implementation Method 1
The neck is elastically deformed away from the arm to create forceful contact between the head and the traces
Implementation Method 2
A float is attached to the arm and is configured to rise and fall with fluid level to pivot the arm relative to the housing
Data Source
AI summary
A fluid-level sensor includes a housing, a substrate supported by the housing and defining an arcuate slot completely though a thickness of the substrate, and electrically conductive traces disposed on a backside of the substrate. A wiper assembly is disposed adjacent to a front side of the substrate and includes an arm pivotal relative to the substrate and a wiper attached to the arm. The wiper has an elongate neck extending through the slot and a head attached to the neck and in contact with the traces to close an electric circuit, wherein the wiper is configured to move along the slot and slide across the traces responsive to pivoting of the arm to vary resistance of the electric circuit to output a fluid-level reading.