Sensor Lead Sealing Strain Relief Coupler

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Solution Overview

Problem

Internal combustion engine temperature sensors face degradation due to harsh conditions such as vibration, debris, moisture, and high temperatures, leading to performance issues and reduced suitability for their intended purpose.

Innovation Solution

A coupler system using a grommet and nugget configuration to mechanically and electrically couple a mineral insulated cable to a wiring harness, providing a high-temperature seal, strain relief, and proper terminal orientation, while reducing moisture intrusion and increasing the continuous use temperature rating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If temperature sensors are exposed to harsh operating conditions in internal combustion engines, then they can perform their sensing function, but their performance degrades due to vibration, moisture, debris, and high temperatures

Engineering Contradiction:
Improvesensor performanceVSAvoidharsh conditions exposure
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a coupler as an intermediary component between the sensor and wiring harness. This coupler includes a grommet that seals around the mineral insulated cable and a strain relief boot that protects the connection point. The coupler acts as a protective mediator that isolates the sensor from harsh environmental factors while maintaining electrical and mechanical connectivity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The strain relief boot and grommet assembly provide beforehand cushioning by creating a protective barrier before moisture, debris, or vibration can reach the sensor or wiring harness connection. The boot is positioned to prevent moisture intrusion and the grommet seals around the cable to block environmental contaminants in advance.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Reliability

If a mineral insulated cable is connected to a wiring harness without proper sealing, then electrical connection is achieved, but moisture intrusion degrades the connection

Engineering Contradiction:
Improveconnection integrityVSAvoidmoisture intrusion
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The grommet serves as a sealing intermediary between the mineral insulated cable and the wiring harness. It creates a moisture barrier while allowing the cable to pass through, preventing moisture intrusion to the connection point while maintaining electrical connectivity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The grommet is implemented as a flexible sealing element that can deform to accommodate the cable while maintaining a tight seal. This flexible shell structure prevents moisture intrusion while allowing for thermal expansion and vibration without compromising the seal integrity.

Inventive Principle:
Principle #30Flexible shells and thin films

3Temperature

If the sensor system operates at high temperatures, then it can monitor exhaust gas temperature, but the continuous use temperature rating is limited by the wiring harness and connection components

Engineering Contradiction:
Improveoperating temperatureVSAvoidcontinuous use temperature rating
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The coupler acts as a thermal intermediary between the high-temperature sensor environment and the lower-temperature wiring harness. The grommet and boot materials are selected to withstand high temperatures while protecting the wiring harness from thermal degradation, effectively extending the continuous use temperature rating.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the material parameters of the coupler components (grommet and boot) to withstand high temperatures. By selecting materials with appropriate thermal resistance and stability, the system can operate continuously at higher temperatures without degrading the wiring harness or connection integrity.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2406606B1Sensor lead sealing and strain relief
Publication Date: 2019.07.31 STONERIDGE INC
  • EP2406606B1 patent drawingFigure 1~2
  • EP2406606B1 patent drawingFigure 3~15
  • EP2406606B1 patent drawingFigure 4~5

AI summary

A sensor system may comprise a wiring harness comprising at least one wire, a grommet, a nugget, a sensor, and a harness sleeve. The grommet may comprise at least one passageway configured to receive the wire. The nugget may comprise at least one terminal molded into the nugget and coupled to the wire. A mineral insulated cable may be coupled to the sensor and to the terminal. The harness sleeve may define at least one cavity configured to receive the nugget and at least a portion of the grommet. The harness sleeve may be coupled to the mineral insulated cable and may include a first crimp coupling the harness sleeve to the grommet. The exterior surface of the nugget may also include at least one radially disposed groove. The harness sleeve may also include a second crimp coupling the harness sleeve to the nugget, for example, about the radial groove.