Fuel Level Sensor Contact Spring U-Shape Design

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Solution Overview

Problem

Existing fuel level sensors with resistance networks and contact spring structures are complex and susceptible to contamination and magnetic interference, which can affect their accuracy and reliability.

Innovation Solution

A fuel level sensor design featuring contact springs with a u-shaped or v-shaped distal end and a stiffening portion to ensure multiple contact points and reduce lateral movement, allowing for reliable contact even with contamination and minimizing magnetic interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the contact spring structure uses multiple contact springs positioned opposite each contact to ensure reliable connection, then the reliability improves, but the device complexity increases

Engineering Contradiction:
Improveconnection reliabilityVSAvoidcontact spring structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The contact spring is divided into multiple contact spring elements (at least two) positioned opposite each electrical contact. This segmentation allows the system to maintain reliability through redundancy while managing complexity by organizing the elements in a structured, opposing arrangement that systematically addresses contamination issues.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The distal end of each contact spring is given a specific U-shaped or V-shaped configuration. This local structural modification concentrates the reliability improvement at the critical contact point without requiring complex changes throughout the entire contact spring structure, thus improving reliability while controlling overall complexity.

Inventive Principle:
Principle #3Local quality

2Stability of the object's composition

If the contact spring elements are mechanically interconnected to restrict lateral movement, then the stability improves, but the ease of manufacture decreases

Engineering Contradiction:
Improvecontact spring stabilityVSAvoidassembly complexity
Core Design Contradiction:
Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

Multiple contact spring elements are mechanically interconnected through a common connection element. This merging approach provides stability by restricting lateral movement of individual elements while simplifying manufacture by using a single connection component that can be integrated into the existing sensor assembly process.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If the distal end of contact spring has u-shaped or v-shaped form to create multiple contact points, then the reliability improves, but the magnetic influence increases

Engineering Contradiction:
Improvecontact reliabilityVSAvoidmagnetic interference
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The U-shaped or V-shaped configuration is applied only to the distal end of the contact spring where contact occurs, rather than throughout the entire spring structure. This localized approach creates multiple contact points for improved reliability while minimizing the amount of magnetic material present, thereby reducing magnetic interference.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The magnetic properties of the contact spring material, which could potentially cause interference, are utilized to enhance the contact force and ensure reliable electrical connection. The magnetic attraction between the contact spring and the magnet helps maintain stable contact pressure, converting what could be a harmful factor into a beneficial force for connection reliability.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 design simplifies the construction of fuel level sensors, ensures reliable contact and reduced magnetic influence, and maintains accuracy even in the presence of contaminants, enhancing the overall performance and robustness of the sensor.

Implementation Method 1

a contact spring structure which can be deflected under the action of a permanent magnet

Methodology Applied
Scientific EffectMagnetic force: Lorentz Force

Implementation Method 2

contact springs being deflectable under the force of the magnet

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3521779B1Fuel level sensor
Publication Date: 2022.03.02 TI AUTOMOTIVE TECHNOLOGY CENTER GMBH
  • EP3521779B1 patent drawingFigure 1~2

AI summary

The invention relates to a fuel level sensor (10), with a magnet (12) being moveable along a circle segment shaped path responsive to the fuel level in a tank, a resistance network (14) comprising a plurality of individual electrical contacts (14a, 14b, 14c,...), a plurality of contact springs (16a, 16b, 16c,...) being deflectable under the force of the magnet (12) in a direction towards the resistance network (14) so as to establish an electrical connection with one individual electrical contact (14a, 14b, 14c,...) of the resistance network (14) depending on the position of the magnet (12) along the circle segment shaped path, the fuel level being determined depending on which individual electrical contact (14a, 14b, 14c,...) of the resistance network (14) is in contact with a contact spring (16a, 16b, 16c,...), characterized in that the distal end of each contact spring (16a, 16b, 16c,...) has a u-shaped or v-shaped form.