daimler presents the lightest of its kind rear axle subframe of the new c-class

Welcome to the 2nd International Lightweight Chassis

& Body Design Conference

Today, we are pleased to share a presentation from our previous Lightweight Chassis

Conference. We hope you enjoy this insight into the Lightweight rear axle subframe of the

Mercedes C-Class by Karl-Heinz Röß, Head of Development/Axle at Daimler AG:

Lightweight rear axle subframe of the new C-Class

1 International Conference „Lightweight Chassis & Frame Design“ | 18.-19.05.2015 | Karl-Heinz Roess

Agenda

Introduction

Design and Simulation

Production Technologies

Testing and Validation

Conclusion


1

2

3

4

5


Introduction 1

1. Task


Design study for a rear axle subframe.

A really high weight reduction and a

concept for different load stages.

Concept Development:

1. Lightweight steel variant with high strength steel

2. Aluminium welded sheet construction

Introduction 1

Agenda

Introduction




Conclusion


1

2

3

4

5

1. Lightweight SteelTechnical requirements:

• High strength steel

• Different material thickness

• Taylored Blank

• Lightweight construction

• Increase the strength of welding area

• Fulfill our requirements for durability and crash

• etc.

Result was approx. 3 kg reduction

International Conference „Lightweight Chassis & Frame Design“ | 18.-19.05.2015 | Karl-Heinz Roess 7

Design and Simulation 2

2. Aluminium Concept

• Technical requirements:

• Welded sheet construction

• Packing similar to the steel version

• Entry subframe for the load case

• Cost/weight ratio

• Fulfill our requirements for durability and crash

• etc.

Result was approx. 5 kg reduction



Difference between aluminium vs. steel

Side shell

Aluminium Steel

Alu side shell:

• welding butt joint (I-Stoss)

• higher thickness

Steel side shell:

• welding lap joint

The thicker aluminium sheet is less sensitive to shape tolerances for I joint.

The thin steel sheet requires a flange to form tolerances in the joint to compensate.



Difference between aluminium vs. steel

Front cross beam

Steel cross beam:

• Single piece cross beam

• U-shape

Alu front cross beam:

• Two pieces cross beam

• L-shape

Aluminium Steel



Load Stage



rear axle load

torq

ue

load case 1

load case 2

component design engineering tenson & expansion calaculation

forming simulation manufacturing simulation

durability calaculation

vehicle simulation

digitale test track


International Conference „Lightweight Chassis & Frame Design“ | 18.-19.05.2015 | Karl-Heinz Roess

Optimization Process


Agenda

Introduction




Conclusion


1

2

3

4

5

15

Manufacturing Steps

Pa

rt s

pe

cific

co

st

Zeit

Welding with Single-Roboter C-Classe bis 2001

2009 2007 1993 2001

Master/Slave (M/S),

Tandemwelding and part handling C-Classe 2001-2007

Welding with Multirobot-Systems:

Cooperating welding system C-Classe BR204

E-Classe


Production Technologies 3

Laser Hybrid Process

auto. weld-seam with

control and repair

2011 2015 2013

Laser induced

plasma shielding gas

flow

weld pool

motion direction

metal wire

electrode

metal vapour

Laser beam

intensity > 106 W/cm2

(deep-welding)

gas metal arc

(GMA) intensity 104

W/cm2

Laser-MSG Hybrid Process

Welding Process

vapour capillary

tube (keyhole)

MSG Laser Laser-MSG

Welding speed + +++ ++++

Process tolerance +++ ++ +++

Joint tolerance (gap, offset) +++ + +++

Machinery availability ++ ++++ +++

Welding speed

Process

tolerance

Joint

tolerances

(gap, offset)

Machinery

availability

Characteristics of the welding process

strengths


MSG MSG - Tandem Laser Plasma-

MSG Hybrid Laser-MSG

Hybrid

Basics / Operating Principle •Combined method of laser and MSG process (Hybrid)

Laser beam intensity bei LLK 400 µm ca. 3*106 W/cm2

Workpiece

Keyhole

Laser beam

gas nozzle

Argon Gas

Electrode Pulsed arc

Droplet detachment

Welding direction

Schematic structure of the hybrid process Laser hybrid process at the T-joint test panel

Xdr* MSG - area

Laser - area



Welding Process


Comparative Processes

Prozess: Laser-MIG Hybrid Prozess: MIG

Without weld support With weld support



Further development Static & Dynamic strength

Smaller size

penetration

Larger size

penetration

Quelle: Prof. Häfele FH – Esslingen Bsp. am T-Stoß

F

Effe

ct

Deep welds Through welds

+

• Add additional welding work with laser hybrid, for example, bracket

• connecting seams better use of static / dynamic strength in highly loaded aluminium - welds

Current Research

Δ 1,8 mio.



Production

The production of the aluminium subframe takes place in fully automated welding cells



Production

The interlinking of the individual manufacturing steps is also a fully automated

.

.



Quality

Compliance with the geometry and the inspection of welds carried out based camera.

.



24

Automatic weld seam optimization workers independently objective assessment

Control and optimize the machine cycle

Automatic documentation of test results

System applicable for steel and aluminium components

Fully automatic inspect welds and optimize them during

production.


Agenda

Introduction

Conception and Calculation



Conclusion


1

2

3

4

5

Testing and Validation 4

International Conference „Lightweight Chassis & Frame Design“ | 18.-19.05.2015 |

Karl-Heinz Roess

Hardware Testing

Digitale Testing

Forming Simulation FE-Calculation

0

5

10

15

20

25

30

0 2 4 6 8 10

Weg [mm]

Kra

ft [k

N]

Berechnungsergebnis W204

Versuch W204

Versuch W204 Bake-hardening Effekt

Versuch W203 (Serie)

Component design

1 27

1

0 1

2 1

3

1

1

9 8 6

4 5 3

1

4

1

5

1

6

26



Test Bench

Material Micrographs


International Conference „Lightweight Chassis & Frame Design“ | 18.-19.05.2015 |

Karl-Heinz Roess


28


Conclusion


Conclusion 5

• Challenging tasks

• High use of simulation and calculation

• Development of new production technologies

• New production methods are being employed (laser-hybrid welding

technology).

• Brought an automatic weld seam control and optimization are used.

• The result is a rear axle subframe for the C-Class

that is the lightest of its kind on the market.


Thank you for your attention -

do you have questions?

Dear Lightweight Chassis Expert,

The 2nd Lightweight Chassis & Frame Design Conference will bring you the latest innovations in

lightweight chassis and components applications. This event will focus on practice-oriented

presentations and will offer you the opportunity to interact with today's most important chassis and

material experts:

Finding best material combination through multi-material joining

Optimizing processes of sheet metal forming

Applying corrosion solutions for maximum protection

Introduce new recycling technologies for lightweight materials to increase part

recovery

For more information and the schedule of events, please download the agenda. If you have any

questions, please email at [email protected] or call +49 (0) 30 20 913 - 274

We look forward to meeting you in February 2016!

Kind regards,

http://www.lightweight-chassis.com/

mailto:[email protected]?subject=Lightweight%20Chassis%20Design%20Conference

daimler presents the lightest of its kind rear axle subframe of the new c-class

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