Sealing Structure With Tapered Surface For Reduced Installation Time
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Solution Overview
Problem
The conventional sealing structure for internal combustion engine components, such as the gap between a cylinder head and an injector, requires manual correction using a jig due to diameter expansion and elasticity issues, leading to increased man-hours and potential sealing performance under varying pressure conditions.
Innovation Solution
A sealing structure featuring a taper-like outer peripheral surface and a stepped surface on the inner peripheral member, allowing the seal ring to be installed in a compressed state without the need for a correcting jig, with the seal ring being compressed between these surfaces to maintain contact under both high and low pressure conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the seal ring is made of synthetic resin material with high heat resistance, then the sealing reliability is improved, but the elasticity is insufficient requiring manual correction with a jig, increasing installation time
Solution Approach 1:
The seal ring is pre-compressed to a predetermined compression rate before installation. This preliminary action ensures that the seal ring maintains sufficient contact pressure with the sealing surface without requiring post-installation correction, thereby reducing installation time while maintaining sealing reliability
Solution Approach 2:
The compression rate of the seal ring is controlled within a specific range (5-20%) to optimize both sealing performance and installation efficiency. By adjusting this parameter, the seal ring achieves adequate elasticity and contact pressure without requiring manual correction
2Reliability
If the seal ring is compressed between the taper-like outer peripheral surface and the installation portion outer peripheral surface, then the close contact surface pressure is increased improving sealing performance, but the installation complexity increases
Solution Approach 1:
A taper-like outer peripheral surface is provided on the inner peripheral member instead of a flat surface. This curved surface design allows the seal ring to be naturally compressed and positioned during insertion, improving sealing performance while simplifying the installation process compared to complex adjustment mechanisms
3Reliability
If the seal ring is displaced by combustion gas pressure to increase close contact surface pressure, then the sealing effectiveness is improved, but the seal ring may deform excessively under high pressure conditions
Solution Approach 1:
The seal ring is pre-compressed to a predetermined compression rate before installation. This preliminary compression creates initial contact pressure that stabilizes the seal ring shape, preventing excessive deformation under combustion gas pressure while maintaining sealing effectiveness
Solution Approach 2:
The seal ring is designed to dynamically adjust its compression state based on operating conditions. Under high pressure, the pre-compressed seal ring maintains shape stability, while under low pressure, it retains sufficient elasticity to ensure continuous sealing contact
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
This solution reduces man-hours during installation and ensures excellent sealing performance under both high and low pressure conditions without the need for post-installation correction, maintaining close contact surface pressure effectively.
Implementation Method 1
the seal ring is arranged in a compressed state between the taper-like outer peripheral surface and the installation portion outer peripheral surface
Implementation Method 2
made of a synthetic resin material, for example, poly tetra fluoro ethylene (PTFE) having a high heat resistance
Implementation Method 3
is displaced to an atmospheric air side space (A) side by pressure P of combustion gas in the combustion chamber (E) side, and is compressed in a diametrical direction
Data Source
Figure 1
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Figure 3
AI summary
The purpose of the present invention is to provide a sealing structure for which the man-hours for seal ring installation are not high and with which excellent sealing properties can be obtained. To achieve said purpose, a seal ring (3) is interposed between an outer member (1) and an inner member (2) fitted by being inserted in the outer member (1). On the outer circumferential surface of the inner member (2), a tapered outer circumferential surface (21), the diameter of which decreases in the direction of insertion of the inner member (2), and an installation section outer circumferential surface (22) that extends from the small diameter end in the insertion direction are formed. On the inner circumferential surface of the outer member (1), a stepped surface (12) located further in the insertion direction than the tapered outer circumferential surface (21) and facing the direction opposite to insertion and an installation section inner circumferential surface (13) extending from the outer diameter edge of the stepped surface (12) in the direction opposite to insertion are formed. The seal ring (3) is disposed in a compressed state between the tapered outer circumferential surface (21) and installation section outer circumferential surface (22) and the stepped surface (12) and installation section inner circumferential surface (13).