Plug Connector Ring Member Sealing Vibration

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Solution Overview

Problem

Increased compression ratios in internal combustion engines lead to higher operating voltages for spark plugs, necessitating plug caps with improved current leakage resistance to prevent electrical current leakage.

Innovation Solution

A plug connector design featuring a rubber member with a ring member of higher hardness on its outer circumference, positioned to increase contact pressure between the rubber member and the spark plug insulator, thereby enhancing sealing and current leakage resistance, and incorporating a metal connector member and high hardness parts for vibration suppression.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the compression ratio of internal combustion engines is increased to improve fuel efficiency, then the operating voltage of spark plugs becomes higher, but current leakage resistance of plug caps deteriorates

Engineering Contradiction:

Improvefuel efficiencyVSAvoidcurrent leakage resistance

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent applies local quality by adding a ring member with higher hardness than the rubber member at specific positions (front and/or rear ends of the rubber member). This localized hardness enhancement creates high-contact-pressure regions that improve sealing performance without changing the entire rubber member's properties, thus preventing current leakage while maintaining the engine's high compression ratio operation

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent uses composite materials by combining the rubber member (softer material) with the ring member (harder material) to create a multi-material structure. The rubber member provides overall sealing and flexibility, while the ring member provides localized high-contact-pressure zones, achieving both sealing performance and current leakage resistance in the plug cap

Inventive Principle:

Principle #40Composite materials

2Reliability

If a ring member with higher hardness than the rubber member is added to increase contact pressure and sealing, then current leakage resistance is improved, but device complexity increases

Engineering Contradiction:

Improvecurrent leakage resistanceVSAvoidplug connector structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the sealing function into two parts: the rubber member provides general sealing and flexibility, while the ring member provides localized high-contact-pressure sealing at critical positions. This segmentation allows each component to focus on its specific function, achieving effective current leakage prevention without requiring complete redesign of the entire plug connector structure

Inventive Principle:

Principle #1Segmentation

3Adaptability or versatility

If the rubber member is made softer to improve sealing flexibility, then adaptability to spark plug variations is improved, but vibration resistance deteriorates

Engineering Contradiction:

Improvesealing flexibilityVSAvoidvibration resistance

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies local quality by placing the harder ring member at specific locations (front and/or rear ends) where vibration resistance is critical, while the main body of the rubber member remains soft to provide sealing flexibility and adaptability to spark plug variations. This localized hardness distribution simultaneously achieves both sealing adaptability and vibration resistance

Inventive Principle:

Principle #3Local quality

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 effectively increases sealing and current leakage resistance while suppressing vibration, preventing metal powder generation and improving the overall strength and vibration resistance of the plug connector.

Implementation Method 1

a ring member arranged on an outer circumference of the rubber member and having higher hardness than that of the rubber member

Methodology Applied

Scientific EffectHardness:

Implementation Method 2

a hollow insulating member made of a rubber material... to prevent current leakage (i.e. leakage of electric current)

Methodology Applied

Scientific EffectElectrical insulation: Dielectric

Data Source

PatentUS10079475B2Plug connector, rubber member, and ring member

Publication Date: 2018.09.18 NITERRA CO LTD

AI summary

A plug connector capable of increasing the sealing between a rubber member and an outer circumferential surface of a spark plug insulator for improvement in current leakage resistance. The plug connector includes a conductive part that electrically connects a spark plug and a power supply member for power supply to the spark plug; and a rubber member that covers the conductive part. The spark plug has an insulator and a terminal electrode protruding toward the rear from a rear end of the insulator. The plug connector further includes a ring member arranged on an outer circumference of the rubber member.