Capacitive Distance Sensor with Insulated Holes for Corrosion Resistance
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Solution Overview
Problem
Capacitive distance sensors in the automotive and other industries face challenges with corrosion and dirt susceptibility, as well as insecure attachment methods, which affect their reliability and longevity.
Innovation Solution
A capacitive distance sensor with an elongated, electrically conductive sensor surface surrounded by an insulating body and featuring uniformly spaced holes for secure fastening, preventing environmental contact and ensuring hermetic sealing, using a flexible copper sensor surface and PVC insulating body, with a termination for electrical connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sensor surface is completely surrounded by an insulating body, then corrosion and dirt susceptibility are prevented, but manufacturing complexity increases
Solution Approach 1:
The sensor surface is completely surrounded by an insulating body, creating a nested structure where the conductive sensor element is embedded within the insulating material. This nesting provides complete environmental protection while maintaining a compact, integrated design that reduces overall complexity despite the protective enclosure.
Solution Approach 2:
The insulating body is designed as a thin-walled structure that completely surrounds the sensor surface. This thin-film approach provides adequate corrosion and dirt protection while minimizing the added complexity and material usage, achieving protection with minimal structural overhead.
2Strength
If holes are introduced into the sensor surface for fastening, then attachment security is improved, but corrosion susceptibility increases
Solution Approach 1:
The insulating body acts as an intermediary material that fills and seals the holes in the sensor surface. This mediator prevents direct contact between the environment and the sensor surface at the hole locations, maintaining attachment security through the fastening holes while preventing corrosion by blocking environmental exposure paths.
Solution Approach 2:
The sensor element combines the conductive sensor surface with an insulating body material to create a composite structure. This composite design allows holes to be present for fastening while the insulating material provides corrosion protection, achieving both attachment security and environmental resistance through material combination.
3Ease of operation
If the sensor element is made flexible with ribbon cable, then ease of installation is improved, but mechanical strength decreases
Solution Approach 1:
The sensor element uses a flexible ribbon cable construction with thin-film conductive layers. This flexible design enables easy installation and conformability to various mounting surfaces, while the thin-film structure provides sufficient mechanical strength for the intended application through its flexibility and adaptability rather than rigid strength.
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 provides a secure, corrosion-resistant, and easily attachable capacitive distance sensor that maintains reliability and longevity, even in harsh outdoor conditions, by ensuring the sensor surface is completely enveloped by the insulating body and using a consistent hole geometry for efficient fastening.
Implementation Method 1
the sensor surface is completely surrounded by an insulating body
Implementation Method 2
When the object approaches the sensor element, the capacitance of the capacitor formed between the sensor surface and the counter-electrode changes. The change in capacitance is measured directly and/or indirectly by means of electronics.
Data Source
Figure 1
Figure 2
AI summary
The invention relates to a capacitive distance sensor (2). The distance sensor (2) comprises a sensor element (4) with an electrically conductive, elongated, flat sensor surface (16) which in turn contains a number of holes (18). The sensor surface (16) is completely enclosed by an electrically non-conductive insulating body (14) such that the insulating body (14) completely covers the edge regions (22) of the holes (18). The sensor element (4) is manufactured, in particular, by first producing the holes (18) in the sensor surface (16). In a subsequent step, the sensor surface (16) is completely enclosed by the insulating body (14), which also completely fills the holes (18) of the sensor surface (16).