No.302012

CX-5

20

14 *5 NVHCAE Body Development Dept. NVH & CAE Technology Development Dept. *6 Vehicle Testing & Research Dept.

CX-5 SKYACTIV-BODY Development of SKYACTIV-BODY Structure for CX-5

1 2 3 Takayuki Kimura Manabu Hashimoto Shigeru Nakauchi 4 5 6 Masamitsu Tanaka Kazuo Kondo Yoshihiro Okada

CX-5 SKYACTIV-BODY

CX-5 CAE VEValue Engineering CD NCAP 8

Summary The CX-5 is Mazdas first production model to adopt the SKYACTIV-BODY. Its light weight body has

achieved a high rigidity that enhances driving pleasure and the highest level of crash safety performance, both of which support Mazdas commitment to making cars that always excite. This article introduces the development process of the CX-5 and its structural features, including the aims and the technologies applied.

Based on the basic principles of mechanics, we designed an ideal body structure and nurtured concept technologies through CAE analyses and vehicle tests before determining the structural details. In addition, we applied VE effective material utilization from an early stage of development so as to offer the vehicle to all our customers at an affordable price. As a result, a body rigidity equivalent to the level of European premium sedan of CD segment has been achieved, the crash safety performance has ranked top in NCAP of major markets, and the vehicle weight has been reduced to a level 8% lighter than the lightest line of the same segment cars.

1.

SKYACTIV-BODY 29 CX-5 TPVTechnology Prove-out Vehicle

SUV

SUV

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VE

2.

2.1

CX-5

CAE Fig.1

Weight

Idealized ofComponent

Method ofConstruction

MaterialThickness

strengthen framesmaximiseperformance

stiffnessenhanced bystrengthen jointMinimumthicknessdetermined bystiffness CAE

Materialselected bynecessarystrength

Straight Frames

Performance

Weight

Maximise

Minimise

780/980Mpa high-tensile

590MPa high-tensile

340/440MPa high-tensile

270MPa high-tensile

1800MPa high-tensile

Increased spot weld pointsWeld bonded sections

Performance

Weight

Performance

Minimise

Continuous Structures

Fig.1 SKYACTIV-BODY Vision

2.2

,

SKYACTIV-BODY 4

, ONE MAZDA

2.3

NVH

Fig.2

Define Load Allocated to Each PartOptimise Detailed Structure

1st Step

2nd Step3rd Step

Look for Ideal Framework

Fig.2 Development Approach

3.

CX-5 3.1

SKYACTIV-BODY CAE CX-5

Fig.3 B_FRAME

Current model

CAE Analysis

CX-5 A Type

Strain Reduction

Deformation Volume ofFloor Increased

Broken surface

B Type C Type D Type E Type

Fig.3 CAE Analysis

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3.2

CX-5 4

Fig.4

,

2.B pillar and under body connected

1.Upper body and under body 4.Rear header and under body connected

3.Rear damper mounts connected

Fig.4 Continuous Structures 3.3

SKYACTIV-BODY CX-5

Fig.5

CX-5Current model

t1.8 t2.3

t2.9

t1.4 t1.6

t2.0

t1.2Upper path

ContinuousStructures

Fig.5 Front Body Structure with Multi-Load Path 3.4

(1)

Fig.6

Rear Wheel House Rear Side Rail

S/Nratio(dB)majorvariability minor

Rear Sus-housing

Fig.6 Contribute Significantly Analysis

0

(2)

Fig.7

Directly receives loads from rearsuspension and restrains vibration

Directly connected tounderbody

Fig.7 Dual Brace

3.5

CX-5CAE

SEAStatistical Energy Analysis

Fig.8

2.4kg

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2t

2t

2t

2t

2t

4t

4t

3t1.6t

2 2 2 2 2 2 2 2 2 22 2 2 22 2 2 22 2 2 2 2 2 2 2 2 22 2 2 2 2 2 22 2 2

2 22 2 2 2

2 2 2 2 22 2 2 2 2

2 2 2 2 2 22 2 2 2 2 2 2 2

2 2 2 2 2 2 2 22 2 2 2 2 2 2 22 2 2 2 2 2 2 2

2 2 2 22

2 2 22

2 22 2 2 22 2 2 2

2 2 2 2 2 22 2 2 2 22 2 2 2 22 2 2 22 2 22 2

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4.5 4.5 4.5 4.5 4.5 4.5 3.5 3.5 3.5 3.5 3.5

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3.5 3.5 3.5 3.5 3.5

3.5 3.5

4.5 4.5

3.5 3.5 3.5 2 3.5 2 3.5 22 2 2 2 2 2 2 2

2 2 2 2 2 2 2 22 2 2 2 2 2 2 2 2 22 2 2 2 2 2 2 2 3.5 2 2 22 2 3.5 3.5 3.5 3.5 3.5 2 3.5 2 3.5 4.5 3.5 2 2 22 2 2 2 3.5 3.5 2 2 2 2 3.5 3.5 3.5

2 2 3.5 3.5 2 2 2 3.5 3.5 2 2 2 3.5 4.5 22 2 2 3.5 4.5 3.5 2 2 2 2 2 2 3.5 3.5 3.5 2 2

2 2 2 3.5 4.5 4.5 3.5 2 2 2 3.5 3.5 2 2 2 2 2 2 22 2 2 3.5 4.5 4.5 3.5 2 2 2 2 2 2 2 2 2 22 2 2 3.5 3.5 3.5 3.5 2 2 2 2 2 2 2 2 2 23.5 2 2 3.5 2 2 2 2 3.5 3.5 3.5 3.5 3.5 3.5 3.5 3.5 2 2 22 2 2 2 2 3.5 3.5 4.5 4.5 4.5 3.5 2 3.5 4.5 4.5 2 22 2 2 3.5 4.5 3.5 3.5 3.5 3.5 2 2 2 3.5 4.5 22 2 2 3.5 2 2 2 2 2 2 2 3.5 3.52 2 2 2 2 2 2 2 2 2 3.5 4.5 3.5 2 2 22 2 2 2 2 2 2 2 2 2 2 23.5 2 2 2 3.5 3.5 2 2 2 2

3.5 2 2 2 2 2 2 22 2 2 2 2 2 2 22 4.5 2 2 2 2 2 2

3.5 2 2 3.5 3.5 3.5 4.5 4.54.5 3.5 2 2 2 2 3.5 4.53.5 3.5 2 2 2 2 3.5 4.52 2 2 2 2 2 3.5 4.52 2 2 2 2 2 3.5 4.52 2 2 2 2 2 3.5 4.52 2 2 2 2 2 3.5 4.52 2 2 2 2 2 3.5 4.52 2 2 2 2 2 3.5 4.53.5 3.5 2 2 2 2 3.5 4.54.5 3.5 3.5 3.5 3.5 3.5 3.5 4.5

3.5 2 2 3.5 3.5 2 3.5 4.54.5 3.5 3.5 3.5 3.5 2 3.5 4.54.5 3.5 4.5 4.5 4.5 3.5 3.5 4.5

4.5 4.5 4.5 3.5 3.5 4.5 4.5 4.5

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4.5 4.5 3.5 3.5 3.5 3.5 4.5 4.5

4.5 3.5 2 2 2 2 3.5 4.53.5 3.5 2 2 2 2 3.5 4.53.5 2 2 2 2 2 3.5 4.52 2 2 2 2 2 3.5 4.52 2 2 2 2 2 3.5 4.52 2 2 2 2 2 3.5 4.53.5 2 2 2 2 3.5 4.5 4.52 2 2 2 2 2 2 2

4.5 3.5

4.5 4.5 3.5 24.5 4.5 3.5 2 3.5 4.5 4.5 4.5 3.5 22 2 3.5 4.5 4.5 4.5 4.5 4.5 3.5 22 2 2 4.5 4.5 4.5 4.5 4.5 4.5 3.52 2 2 2 2 2 2 4.5 4.5 4.5

2 2 2 3.5 3.5 3.5 3.53.5 3.5 2 3.5 3.5 2 3.5

4.5 4.5 4.5 4.5 4.5 3.5 2 3.5 2 3.54.5 4.5 4.5 4.5 4.5 4.5 3.5 3.5 2 3.54.5 4.5 4.5 4.5 4.5 4.5 4.5 4.5 3.5 4.5

3.5 4.5 4.5 4.5 4.5

4.5 3.5 3.5 3.5 3.5

4.5 4.5 4.5 4.5 3.5 3.5 3.5 3.5 2 3.54.5 4.5 4.5 4.5 3.5 3.5 3.5 3.5 2 3.54.5 4.5 4.5 4.5 3.5 2 3.5 3.5 2 3.5

3.5 2 3.5 3.5 3.5 2 3.52 2 2 3.5 3.5 3.5 3.5

2 2 2 3.5 4.5 4.5 4.5 4.52 2 3.5 4.5 4.5 4.5 4.5 4.53.5 3.5 4.5 4.5 4.5 4.5 4.5 4.5

4.5 4.5 4.5 4.5 4.5 4.5 4.5 4.5

4.5 4.5 4.5 4.5 4.5 4.5 4.5 4.5

4.5 4.5 4.5 4.5 4.5 4.5

4.5 4.5 4.5 4.5 4.5 4.5

4.5 4.5 4.5 4.5 4.5 4.5 4.5 4.5

4.5 4.5 4.5 4.5 4.5 4.5 4.5 4.5

4.5 4.5 4.5 4.5 4.5 4.5 4.5 4.5

4.5 4.5 4.5 4.5 4.5 4.5 4.5 4.5

4.5 4.5 4.5 4.5 4.5 4.5 4.5 4.5

4.5 4.5 4.5 4.5 4.5 4.5 4.5 4.5

4.5 4.5 4.5 4.5 4.5 4.5

4.5 4.5 4.5 4.5

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4.5

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4.5 4.5 4.5 4.5 4.5 4.5 4.5 4.5

4.5 4.5 4.5 4.5 4.5 4.5 4.5 4.5

4.5 4.5 4.5 4.5 4.5 4.5 4.5 4.5

4.5 4.5 4.5 4.5 4.5 4.5 4.5 4.5

4.5 4.5 4.5 4.5 4.5 4.5 4.5 4.5

4.5 4.5 4.5 4.5 4.5 4.5 4.5 4.5

4.5 4.5 4.5 4.5 4.5 4.5

4.5 4.5 4.5 4.5 4.5 4.5

4.5 4.5 4.5 4.5 4.5 4.5 4.5 4.5

4.5 4.5 4.5 4.5 4.5 4.5 4.5 4.5

3.5 3.5 4.5 4.5 4.5 4.5 4.5 4.5

2 2 3.5 4.5 4.5 4.5 4.5 4.52 2 2 3.5 4.5 4.5 4.5 4.5

4.5

4.5

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4.5

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4.5

4.5

4.5

4.5

4.5

4.5

4.5

4.5

4.5

4.5

4.5

2.0t

3.5t

4.5t30

Damping sheet

Damping coat4.5t3.5t2.0t

Fig.8 Setting Range

3.6

CX-5

CAE

Fig.9

-2.5E-04

-2.0E-04

-1.5E-04

-1.0E-04

-5.0E-05

0.0E+00

5.0E-05

1 2 3 4 5 6 7 8 9 10 11 12 13 14

time [sec]

Floor angle [deg]

Kinematic Analysis

Static Analysis

With tunnel-braceWithout tunnel-brace

Under- cross member

Cornering force

Gravity

Fig.9 Under- Cross Member

3.7

Cd

Fig.10 Fig.11

Fig.10 Aerodynamics Performance

1 Radiator under cover2 Engine under cover3 Front tire deflector4 Center f loor under cover5 Tunnel cover(4WD)6 Rear tire deflector7 Silencer

1

3

3

2

54

4

6

6

7

Fig.11 Under Cover

3.8

1,800MPa

4.8kg REINF_BUMP

4. VE

4.1

60

60 40CX-5

70

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Add Reinforcement

Add Gusset

Move Hole Location

1.Ridgeline

3.Spotweld Work Hole

2.Radius End

Weak Point of Initial CAEResult

CountermeasureStrucyure

4.2

1

5. CAE Fig.13 Rigidity Structure Improvement