Dual-Layer Suspension Coating Resists Chipping

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Solution Overview

Problem

Epoxy resin-based coatings on vehicle suspension members are prone to chipping, cracking, and corrosion due to contact with seats and accumulation of debris, leading to early breakage, and the rubber bush structure in stabilizer bars can trap debris, causing damage.

Innovation Solution

A dual-layer coating system comprising an epoxy resin-based coating as the first layer and an epoxy-fluororesin-based coating as the second layer is applied to the suspension members, enhancing protection against corrosion and wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an epoxy resin-based coating is applied on the suspension member, then corrosion protection is improved, but the coating is broken due to chipping phenomenon in cold districts and wears out by cracking when firmly contacted with seats

Engineering Contradiction:

Improvecorrosion protectionVSAvoidcoating integrity

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent applies a composite coating structure consisting of an epoxy resin-based first layer and a fluororesin-containing second layer. The epoxy resin layer provides strong adhesion and corrosion protection, while the fluororesin layer adds flexibility and resistance to chipping and cracking. This composite structure resolves the contradiction by combining materials with complementary properties to maintain both corrosion protection and coating integrity under mechanical stress and cold conditions.

Inventive Principle:

Principle #40Composite materials

2Reliability

If grains of mud, sand and gravel enter the crevice between the end turn portion and washer, then the epoxy resin-based coating is damaged accelerated, but the dual-layer coating prevents this damage

Engineering Contradiction:

Improvecoating durabilityVSAvoiddebris accumulation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the surface properties of the coating by incorporating fluororesin in the second layer, which modifies parameters such as surface energy, friction coefficient, and hardness. These parameter changes result in a smoother, more resilient surface that is less susceptible to debris accumulation and coating damage from gravel and sand, thereby improving durability without compromising protective function.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If a rubber bush is used as mounting fixture for stabilizer bar, then mounting flexibility is improved, but grains of mud, sand and gravel are caught in the crevice causing damage

Engineering Contradiction:

Improvemounting flexibilityVSAvoiddebris trapping

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies different coating characteristics to different portions of the stabilizer bar, with the fluororesin-containing second layer specifically applied to areas prone to debris accumulation and mechanical contact. This local quality enhancement provides targeted protection at crevice areas while maintaining the overall flexibility and mounting adaptability of the rubber bush structure.

Inventive Principle:

Principle #3Local quality

Data Source

PatentEP3187747B1Suspension member for vehicles

Publication Date: 2020.11.25 NHK SPRING CO LTD

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AI summary

A vehicle suspension member (10) comprises a body (11) of a vehicle suspension member made of a metal, a first layer (121) provided to cover the surface of the body (11) and a second layer (122) provided to cover at least a portion of the surface of the first layer (121). The first layer (121) comprises an epoxy resin and the second layer (122) comprises an epoxy resin and a fluororesin.