Seal Chain Lip Geometry for Tensile Strength and Torque

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Solution Overview

Problem

Conventional seal chains with sealing members in a + shape section face issues with reduced tensile strength and increased flexing torque due to larger clearance between inner and outer link plates, leading to premature sealing member exhaustion and reduced abrasion resistance.

Innovation Solution

A seal chain design featuring a sealing member with a + shape section in its natural condition, where the first lip portion is circular or close to circular, and third and fourth lip portions are mirror-symmetrical with sloped outer diametric side faces, widening towards the center base portion, and a diagonal line length within a specific range relative to the clearance, allowing for reduced clearance between link plates while maintaining lubricant retention and sealing functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the clearance between inner and outer link plates is increased to accommodate the sealing member, then the sealing member can be properly installed and function, but the tensile strength of the chain is reduced

Engineering Contradiction:
Improvesealing functionVSAvoidtensile strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The sealing member's cross-sectional shape is changed from a conventional form to a + shape with specific dimensional parameters. The diagonal line length z of the center base portion is controlled within a specific range (0.04p to 0.07p where p is chain pitch), and the width of lip portions are optimized. These parameter changes allow the sealing member to fit within reduced clearance while maintaining sealing effectiveness, thereby resolving the contradiction between sealing function and tensile strength.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the clearance between inner and outer link plates is increased, then the sealing member can be installed, but the flexing torque of the chain increases

Engineering Contradiction:
Improvesealing functionVSAvoidflexing torque
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The + shaped cross-section with optimized dimensional parameters (diagonal line length z within 0.04p to 0.07p, specific lip portion widths) enables the sealing member to occupy minimal space between link plates. This reduces the clearance requirement, which in turn reduces the flexing torque during chain operation, resolving the contradiction between sealing function and energy consumption.

Inventive Principle:
Principle #35Parameter changes

3Strength

If the sealing member is made smaller to reduce clearance, then the tensile strength improves, but the sealing member exhausts prematurely

Engineering Contradiction:
Improvetensile strengthVSAvoidsealing member life
Core Design Contradiction:
StrengthVSDuration of action of stationary object

Solution Approach 1:

The + shaped cross-section with optimized parameters provides sufficient material volume (diagonal line length z within specific range) to ensure long service life while maintaining compact dimensions. The specific configuration of lip portions (first lip portion width 2r1, third and fourth lip portion widths b) ensures adequate sealing contact area, preventing premature exhaustion while enabling reduced clearance for higher tensile strength.

Inventive Principle:
Principle #35Parameter changes

4Strength

If the sealing member is made smaller to reduce clearance, then the tensile strength improves, but the abrasion resistance decreases

Engineering Contradiction:
Improvetensile strengthVSAvoidabrasion resistance
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The optimized + shaped cross-section with specific dimensional parameters ensures adequate sealing member size for durability. The lip portion widths (first lip portion 2r1, third and fourth lip portions b) are controlled to provide sufficient contact area with link plates, ensuring adequate abrasion resistance while maintaining the reduced clearance necessary for high tensile strength.

Inventive Principle:
Principle #35Parameter changes

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 enhances tensile strength, improves abrasion resistance, and balances flexing torque and sealing performance by ensuring the sealing member is effectively twisted and securely attached between link plates, preventing premature exhaustion and maintaining sealing function over time.

Implementation Method 1

said sealing member is twisted by turning moment generated based on contact with said bush head portion

Methodology Applied
Scientific EffectTurning moment: Torque

Implementation Method 2

said sealing member...is deformed approximately into a shape of X in section and is sandwiched between said inner and outer link plates

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP1734282B1Seal chain and manufacturing method thereof
Publication Date: 2012.04.04 DAIDO KOGYO CO LTD
  • EP1734282B1 patent drawingFigure 1
  • EP1734282B1 patent drawingFigure 2A~2B
  • EP1734282B1 patent drawingFigure 3

AI summary

There is provided a seal chain in which a sealing member having a shape of + in section is steadily twisted (turned) and deformed into a shape of X and whose abrasion resistance and flexing torque are improved. The sealing member (13) is formed such that inner diametric side end faces (q) of third and fourth lip portions (13c and 13d) extending in a transverse direction from a center base portion (13e) extend in a direction orthogonal to a radial direction and outer diametric side end faces (u) thereof are formed as tapered faces such that width of said lip portion is widened from an edge face toward the base portion. A diagonal distance (z) of the center base portion (13e) is within a range of 0.8 to 1.0 of a clearance (i) between inner and outer link plates.