Vehicle Side Rail Laser Welding for Strength and Weight

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Solution Overview

Problem

Conventional vehicle side rails face challenges in achieving sufficient load absorption performance and vehicle body strength without significant weight increase, particularly due to the limited effectiveness of reinforcing members joined by arc welding, which often result in increased weight and reduced rust-proofing efficiency.

Innovation Solution

The implementation of a side rail with a closed-section structure featuring base members and plate members of different thickness and material, joined by laser welding, allowing for optimized load absorption and strength without the need for arc-welded reinforcing members, and enabling effective buckling deformation during collisions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If arc welding is used to join reinforcing members to the inner surface of the side rail, then the vehicle body strength is improved, but the weight of the vehicle body increases significantly

Engineering Contradiction:

Improvevehicle body strengthVSAvoidweight of vehicle body

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

The patent replaces arc welding with laser welding to join the reinforcing member to the side rail. Laser welding provides sufficient strength while using less material, thereby avoiding significant weight increase. The laser-welded joint achieves reliable connection between the reinforcing member and the side rail without requiring the additional material thickness that would result from arc welding processes.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the joining method from arc welding to laser welding, which alters the thermal process parameters and material interaction. This parameter change enables more precise control of the weld zone, reducing the heat-affected area and allowing for thinner, lighter components while maintaining structural integrity and load absorption performance.

Inventive Principle:

Principle #35Parameter changes

2Strength

If arc welding is used to join reinforcing members, then the load absorption performance is improved, but the rust-proofing efficiency is reduced due to clearance and spatter

Engineering Contradiction:

Improveload absorption performanceVSAvoidrust-proofing efficiency

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent replaces arc welding with laser welding, which eliminates the spatter and oxidized scale problems associated with arc welding. Laser welding produces a cleaner joint with no clearance gaps, providing superior rust-proofing efficiency while maintaining the load absorption performance through precise joining of the reinforcing member to the side rail.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent converts the potential harm of welding by selecting laser welding, which transforms the joining process into one that creates a seamless, gap-free connection. This eliminates the clearance and spatter issues that would otherwise compromise rust-proofing, while the precise energy delivery of laser welding ensures adequate load absorption capability.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Strength

If the plate thickness of the reinforcing member is increased to eliminate clearance, then the vehicle body strength is improved, but the weight of the vehicle body increases significantly

Engineering Contradiction:

Improvevehicle body strengthVSAvoidweight of vehicle body

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

The patent replaces arc welding with laser welding, which provides sufficient joining strength without requiring increased plate thickness. The laser-welded joint creates a strong connection between the reinforcing member and side rail, eliminating the need for thicker plates while avoiding significant weight increase.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the welding process parameters by using laser welding instead of arc welding. This parameter change enables effective joining with thinner materials, as laser welding delivers concentrated energy that creates strong bonds without the need for excessive material thickness, thereby maintaining strength while reducing weight.

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

This configuration achieves the required load absorption and vehicle body strength without weight increase, enhances rust-proofing by eliminating clearance and reducing spatter and oxidized scale, and demonstrates improved stress distribution and corrosion resistance.

Implementation Method 1

The plate members have a laser-welded joint that is a joint portion at which the plate members are joined to the base members by laser welding

Methodology Applied

Scientific EffectLaser welding: Laser Beam Welding

Data Source

PatentUS10689035B2Side rail and manufacturing method of side rail

Publication Date: 2020.06.23 TOYOTA JIDOSHA KK

AI summary

A side rail includes base members, and plate members that are different in both plate thickness and material from the base members. The base members have a cutout or an opening, and the plate members are fitted into this cutout or opening and joined to the base members by laser welding.