Seal Ring Structure for Sensor Shafts to Prevent Rotation-Induced Leakage

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Solution Overview

Problem

The existing sealing structures in electronic devices, such as photoelectric sensors, suffer from reduced sealing performance due to excessive rotation of sealants caused by friction when the setting parts are operated, leading to potential liquid infiltration.

Innovation Solution

A seal ring with a curved surface part and a pair of end parts, where the end parts have a shape different from the curved surface part and extend along the axial direction, is used to surround the shaft and housing, allowing the end parts to contact either the shaft or the housing during operation, thereby suppressing excessive rotation and maintaining sealing performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the seal ring is made to contact the shaft to prevent liquid infiltration, then sealing is improved, but the setting part operation becomes restricted due to excessive rotation suppression

Engineering Contradiction:
Improvesealing performanceVSAvoidoperation freedom
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

Different portions of the seal ring are designed with different properties: the curved surface part provides sealing contact, while the end parts with different shapes provide controlled operational contact. This local differentiation allows the seal ring to maintain sealing performance while permitting necessary operational movement without excessive rotation.

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

This configuration effectively prevents a decrease in sealing performance by ensuring the seal ring remains in contact with either the shaft or the housing, thereby maintaining the integrity of the seal even during operation, without compromising the device's operability.

Implementation Method 1

a seal ring (60) in an annular shape... surrounds the shaft (18b)... seals a gap between the shaft (18b) and the housing (12)

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3940733B1sensor
Publication Date: 2024.08.28 OMRON CORP
  • EP3940733B1 patent drawingFigure 1
  • EP3940733B1 patent drawingFigure 2
  • EP3940733B1 patent drawingFigure 3

AI summary

Provided are a sensor and electronic device that enable reductions in the sealing performance of a sealant to be minimized. The sensor 10 comprises a setting part 18 which changes settings of a main sensor unit, and an annular seal ring 60, which is disposed so as to encircle a shaft 18b of the setting part 18, and seals a gap between the shaft 18b and a housing 12. The seal ring 60 comprises a curved surface section 61 which curves outward as seen in cross section, and a pair of end sections 62a, 62b, on both sides of the curved surface section 61 in the axial direction of the seal ring 60, which have a different shape from the curved surface section 61 and extend in the axial direction of the seal ring 60.