Sealing Device Sub Lip Stepped Shape Pressure Distribution
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Solution Overview
Problem
Conventional sealing devices face challenges in achieving both effective shaft insertion and sealing performance, particularly when the shaft is inserted with eccentricity, leading to a turn-up phenomenon in the sub lip that compromises sealing efficiency.
Innovation Solution
The sealing device features a sub lip formed to face the main lip side with a stepped shape, distributing contact pressure unevenly towards the outside, preventing turn-up and enhancing sealing performance by reducing contact pressure from the outside towards the inside.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the sub lip is formed into a shape directed to the machine outside side to prevent turn-up during shaft insertion, then the shaft inserting property is improved, but the sealing performance is lowered because the contact pressure peak position shifts toward the machine inside
Solution Approach 1:
The sub lip is designed with non-uniform thickness along its width, creating different local properties: the first half (from lip end toward base) has greater thickness to provide structural support and prevent turn-up during insertion, while the second half has reduced thickness to position the contact pressure peak toward the machine outside for effective sealing. This local variation in thickness resolves the contradiction between insertion ease and sealing performance.
2Reliability
If the sub lip is formed into a vertical shape or directed toward the main lip side to improve sealing performance, then the contact pressure peak is positioned toward the machine inside, but the shaft inserting property deteriorates due to turn-up phenomenon
Solution Approach 1:
The sub lip employs non-uniform thickness distribution where the first half (from lip end toward base) has greater thickness to prevent turn-up during shaft insertion, while the second half has reduced thickness to position the contact pressure peak toward the machine outside. This local differentiation resolves the contradiction between sealing performance and insertion ease.
3Reliability
If a dedicated sub lip is added to prevent foreign material intrusion, then the sealing performance is improved, but the device complexity increases
Solution Approach 1:
The sub lip is integrated into the same elastic body as the main lip, forming a unified sealing structure. This merging approach provides dedicated foreign material prevention functionality through the sub lip while avoiding the complexity of separate components, as both lips are molded as a single piece with the elastic body and metal ring assembly.
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 configuration ensures stable shaft insertion and improved sealing performance by preventing turn-up and optimizing contact pressure distribution, achieving both properties simultaneously.
Implementation Method 1
a stepped shape is provided in the sub lip, the stepped shape unevenly distributing contact pressure within a contact width in the sub lip in relation to the shaft to generate a position of a contact pressure peak towards the machine outside
Data Source
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AI summary
The purpose of the invention is, in a sealing device comprising a main lip to seal a sealing fluid inside an apparatus and an auxiliary lip to prevent intrusion of foreign bodies from outside the apparatus, to prevent occurrences of lip curling on the auxiliary lip and achieve both shaft insertion properties and sealing properties even when a shaft is inserted from the auxiliary lip side relative to the sealing device and the shaft insertion is misaligned to a large degree. To achieve this purpose, a sealing device comprising a main lip to seal a sealing fluid inside an apparatus and an auxiliary lip to prevent intrusion of foreign bodies from outside the apparatus and having a structure that allows both lips to slidably contact the circumferential face of a shaft is characterized in that the auxiliary lip is formed to be perpendicular to the axial direction or formed to face the main lip side and the auxiliary lip is provided with a stepped shape to unevenly distribute, toward the outside the apparatus, the location where the contact pressure peak is generated on the shaft in the auxiliary lip.