Engine Plug Tube Seal with Radial Grip for Tool-Free Removal
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Solution Overview
Problem
The existing seal member designs for spark plug fitting holes require significant effort and tools for removal, leading to inefficiencies in maintenance and potential damage during the process.
Innovation Solution
An elastically deformable seal member with a handling portion protruding from the fitting hole, allowing for easy removal by pressing inward radially, and a cap member design that prevents foreign matter ingress and facilitates tool-free attachment and detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the seal member is pressure-fitted in the spark plug hole to ensure secure engagement, then the sealing reliability is improved, but the difficulty of removal increases requiring tools and significant effort
Solution Approach 1:
The seal member is divided into functionally distinct segments: a base portion for engagement, a seal lip portion for sealing, and a handling portion for removal. This segmentation allows each part to optimize its function - the base portion ensures secure pressure-fitted engagement for reliability, while the separate handling portion enables easy tool-free removal by pressing inward to release the engagement
Solution Approach 2:
The handling portion enables the seal member to be removed by itself through elastic deformation when pressed inward, releasing the engagement between the base portion and the fitting hole. This self-service mechanism eliminates the need for external tools or significant effort for removal, directly addressing the ease of operation requirement while maintaining the secure engagement needed for sealing reliability
2Ease of operation
If the seal member is made highly elastic for easy deformation during removal, then the ease of removal is improved, but the structural stability during installation deteriorates
Solution Approach 1:
Different portions of the seal member have different rigidity characteristics tailored to their specific functions. The handling portion is designed with higher rigidity than the seal lip portion, providing structural stability during installation and handling, while the seal lip portion maintains sufficient elasticity for sealing. This local differentiation of mechanical properties resolves the contradiction between overall elasticity for removal and structural stability during installation
3Ease of manufacture
If the seal member structure is simplified for easy manufacturing, then the ease of manufacture is improved, but the sealing performance deteriorates due to insufficient engagement features
Solution Approach 1:
The seal member is segmented into distinct functional portions (base portion, seal lip portion, handling portion), each with specific geometric features optimized for its function. The base portion includes engagement features like protrusions or grooves that mate with corresponding features in the fitting hole, ensuring reliable sealing performance. These segmented features can be manufactured using standard molding or machining processes, maintaining ease of manufacture while achieving reliable sealing through proper geometric design
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
Enhances work efficiency in removing and attaching the seal member without tools, while maintaining airtight and liquid-tight seals by ensuring proper engagement and support, reducing the risk of damage and sealing failures.
Implementation Method 1
the handling portion elastically deforms such as to shrink inward in the radial direction
Implementation Method 2
a seal lip portion that elastically contacts an outer circumferential surface of the cylindrical member
Data Source
AI summary
A seal member (3) is disposed between a cylinder head cover (1) in which an ignition plug mounting hole (1a) is formed and a plug tube (2) which is inserted in the ignition plug mounting hole (1a). The seal member (3) is provided with: a base section (31) configured to be elastically deformable and inserted into the ignition plug mounting hole (1a); a protrusion section (32) formed so as to protrude outward in the radial direction from the outer peripheral surface of the base section (31) and engaging with a groove (12b) formed in the inner peripheral surface of the ignition plug mounting hole (1a); a seal lip section (33) in elastic contact with the outer peripheral surface of the plug tube (2); and a grip section (34) formed between the base section (31) and the seal lip section (33) and protruding downward from the ignition plug mounting hole (1a).