CV Joint Boot Fixing Band With Self-Repairing Alloy Plating

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Solution Overview

Problem

Fastening bands for constant velocity universal joints face issues with corrosion resistance due to peeling of plating or coating at cut ends and engagement contact points, leading to unsatisfactory sealing and increased costs.

Innovation Solution

A fastening band with a zinc-aluminum-magnesium alloy plating layer that self-repairs by forming a dense protective film, covering exposed peeling parts and providing enhanced corrosion resistance, combined with a steel plate of specific mechanical properties (tensile strength ≥270 MPa and elongation at fracture ≥30%) to ensure stable fastening.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a plated steel plate is used for the fastening band, then strength and corrosion resistance are improved, but plating peels during cutting or pressing causing exposed cut end surfaces to corrode

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidplating peeling during cutting/pressing
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies preliminary anti-corrosion treatment by forming a protective film on the steel plate surface before cutting or pressing operations. This preventive measure ensures that even if plating peels during subsequent manufacturing steps, the exposed surfaces remain protected against corrosion, thus resolving the contradiction between maintaining plating integrity during manufacturing and ensuring corrosion resistance.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If plating or coating is applied to the fastening band, then corrosion resistance is improved, but cost increases due to additional plating treatment or coating treatment

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the material parameters by selecting a steel plate with specific composition (carbon content 0.15-0.35%, silicon content 0.01-0.05%) and surface properties that inherently provide corrosion resistance. This parameter optimization allows achieving adequate corrosion protection without requiring additional expensive plating or coating treatments, thus resolving the contradiction between corrosion resistance and manufacturing cost.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the fastening band is made from metal with good corrosion resistance, then reliability is improved, but cost is increased

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidcost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs a composite approach by combining a carefully selected steel base material with a controlled protective surface layer. The steel plate has optimized composition (including carbon, silicon, and controlled impurities) that provides inherent corrosion resistance, eliminating the need for expensive stainless steel or additional protective coatings, thus resolving the contradiction between reliability and cost.

Inventive Principle:
Principle #40Composite materials

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 solution provides excellent rust preventiveness and corrosion resistance while maintaining a stable fastening force, reducing costs by preventing plating peeling and oxidation at cut ends and engagement contact points.

Implementation Method 1

the plating layer has the self-repairing function and can cover the plating peeling part with the protective film formed of the component dissolved from the plating layer

Methodology Applied
Scientific EffectSelf-repairing plating layer:

Implementation Method 2

a dense zinc-based protective film containing aluminum-magnesium is formed as a protective film

Methodology Applied
Scientific EffectProtective film formation:

Data Source

PatentEP3306115B1Fixing band for constant-velocity universal joint boot
Publication Date: 2021.03.03 NTN CORP
  • EP3306115B1 patent drawingFigure 1A~1B
  • EP3306115B1 patent drawingFigure 2A~2B
  • EP3306115B1 patent drawingFigure 3A~3B

AI summary

Provided is a fastening band including a steel plate (111) plated with a plating layer (110) as a base material. The plating layer (110) has a self-repairing function of forming a protective film (112) on a plating peeling part with a component dissolved from the plating layer. The steel plate plated with a zinc-aluminum-magnesium alloy is used as the base material. The plating layer contains 4.0 mass% to 14.0 mass% of aluminum, 1.0 mass% to 10.0 mass% of magnesium, and the balance of zinc. The plating layer contains aluminum and magnesium in a total content of 15 mass% or less and zinc in a content of 85 mass% or more.