engineering design of a vehicle glovebox

Engineering Design of an Automotive Glovebox

Presentation by Charlie Tokowitz

OverviewResearch

• Problem Definition

• Competitivebenchmarking

• Patent research

Embodiment Design

• Industrial design

• Concept generation

• Evaluating concepts

Detail Design

• Mechanical analysis

• CAD design

• MaterialsSelection

• Location strategies and tolerance

Validation

• FEA

• FMEA

• Cost

• Target quantification

• (Prototyping)

• (User Testing)

Manufacturing & Assembly

Craftsmanship

Getting Started

Problem Definition

• Functional requirements

• User needs

• Opportunity identification• Looking back

• Looking ahead

• Manufacturing + Craftsmanship

Competitive Benchmarking

• Determine relevant specifications• Gap & flush (fit)

• Time to open

• Usable storage volume

• Yield point

• Qualitative analysis• Location

• Finish

• Mechanisms Source: The Automotive Body Vol I: Components Design – Morello et al.

Specifications Sheet

Benchmarks

Metric (units) Ideal Value Source ‘07 BMW 3 Srs.

‘11 Subaru Out.

‘07 Acura TSX ‘15 Volkswagen SportWagen

Volume (l) 6-8 TheAutomotive Body Vol I

n/a n/a n/a n/a

Gap (in) .15 TheAutomotive Body Vol I

.15 .175 .08 .17

Flush (in) .15 TheAutomotive Body Vol I

.10 n/a .20 .08

Time to open (s)

5 benchmarking

12.1 3.0 2.9 0.9

Cost (USD) $66.25 (As low as possible)

3rd party resellers

75.00 46.99 92.95 50.00

Patent Research

• Learning from prior art• Mechanical insight

• Product evolution

• Avoid infringement and identify innovation opportunities

• Understand market to differentiate and add value

Audi AG – 1996“Movable glove compartment having a rear mounted, remotely actuated lock”

Ford Global – 2017“Versatile instrument panel storage”

Ford Global – 2012“Vehicle stowage assembly having electromagnetic enclosure”

Embodiment Design

Concept Study

Detail Design

The Classic

Engineering Analysis

𝜃

β

Fg

Fd

Ry

Rx

vd

vxcom

𝜃 + 2𝛽 = 180𝛽 = 90 − 𝜃/2 𝐹𝑑 = 𝑏 × 𝑣𝑑

𝑣𝑑 = 𝑝𝑟𝑜𝑗𝑣𝑑𝑣𝑥𝑐𝑜𝑚

𝑣𝑑 = 𝑣𝑥𝑐𝑜𝑚 cos𝜃

2

𝑣𝑥𝑐𝑜𝑚 =𝑙

2× 𝜃′

𝑣𝑑 =𝑙

2× 𝜃′ × cos

𝜃

2

𝜏 = 𝐹𝑔𝑙

2− 𝐹𝑑

𝑙

2

𝜏 = 𝑚𝑔 sin 𝜃𝑙

2− 𝑏𝑙

2× 𝜃′ × cos

𝜃

2×𝑙

2× cos

𝜃

2

𝐼 × 𝜃′′ =𝑙

2[𝑚𝑔 sin 𝜃 − 𝑏

𝑙

2

2

× 𝜃′ × cos𝜃

2

2

]

Latch Design

M

Rx

Flatch

L/3

L

dashboard

Glove door

M

Rx

Fspring

L/3

L

Ry

Latch Design

L/3

L

h

b

Flatch

𝐼 =𝑏ℎ3

12

𝜎𝑚𝑎𝑥 =𝑀𝑐

𝐼=𝐹𝑙𝑎𝑡𝑐ℎ ×

𝐿3ℎ2

𝑏ℎ3

𝜎𝑚𝑎𝑥 < 𝑌𝑖𝑒𝑙𝑑 𝑆𝑡𝑟𝑒𝑛𝑔𝑡ℎ

Moment

Latch Design

L/3

L

h

b

Flatch

𝐼 =𝑏ℎ3

12

𝜎𝑚𝑎𝑥 =𝑀𝑐

𝐼=𝐹𝑠𝑝𝑟𝑖𝑛𝑔 cos 45° × 𝐿 ×

ℎ2

𝑏ℎ3

𝜎𝑚𝑎𝑥 < 𝑌𝑖𝑒𝑙𝑑 𝑆𝑡𝑟𝑒𝑛𝑔𝑡ℎ

Mo

men

t

Materials Selection

• Which characteristics are most important for the application?• YS

• Cost

• Flammability

• Manufacturability

• Craftsmanship considerations• Visual quality

• Mechanical loss coefficient

“Predominantly the material used is Polypropylene

with mineral filler. Usually, the drawer is a separate

injection moulded part assembled on the dashboard

body.

This choice does not only arise due to economical

reasons, but from technical reasons as well; in fact the

sound absorption characteristic of polypropylene is

taken into account since in this application it is

particularly important to attenuate possible noises

caused by the objects contained in the drawer.”

Source: The Automotive Body Vol 1 p. 516

• PPH vs PPC

• H: stiffer, stronger

• C: better impact

resistance

• V-0 vs HB

• CTE

• Cost of part: $3.30

Drawer Fabric


• Stain resistance

• Cabin temperature

• Sensory targets

Automotive velour suede:

• Cost of material: $1.45

• Bonds to plastic: $0.30

Drawer Trim


• Sensory targets

Automotive leather:

• Cost of material: $6.27

• Bonds to plastic: $0.30

Prefabricated Components

Piano Hinge (steel)

• $1.48/unit

• 0.09 lbs.

Linear Speed Limiter (Cr-plated steel)

• $40.84/unit

• 0.778 lbs.

1

3

2

4

Number Part

1 Dashboard

2 Glovebox Drawer3 Linear Damper

4 Hinge

A A

B B

C C

D D

E E

F F

G G

H H

J J

K K

L L

M M

16

16

15

15

14

14

13

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12

11

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10

10

9

9

8

8

7

7

6

6

5

5

4

4

3

3

2

2

1

1

DRAWN

CHK'D

APPV'D

MFG

Q.A

UNLESS OTHERWISE SPECIFIED:

DIMENSIONS ARE IN MILLIMETERS

SURFACE FINISH:

TOLERANCES:

LINEAR:

ANGULAR:

FINISH: DEBURR AND

BREAK SHARP

EDGES

NAME SIGNATURE DATE

MATERIAL:

DO NOT SCALE DRAWING REVISION

TITLE:

DWG NO.

SCALE:1:5 SHEET 1 OF 1

A1

WEIGHT:

exploded_view

55°

6.7

5

9.1

750

0.0

75

1.00 A

A

B

F

90°

0.75 A

1.075 A

A

3.00 ±0.01

0.10 + 0.020.00

11.80 ±0.05

0.10 + 0.020.00

3.00 ±0.01

0.1

38 + 0

.012

0.0

00

8.9

36 + 0

.014

0.0

00

VIEW NORMAL TO SURFACE OF DASH (DATUM B)

A A

B B

C C

D D

E E

F F

G G

H H

J J

K K

L L

M M

16

16

15

15

14

14

13

13

12

12

11

11

10

10

9

9

8

8

7

7

6

6

5

5

4

4

3

3

2

2

1

1

DRAWN

CHK'D

APPV'D

MFG

Q.A



SURFACE FINISH:

TOLERANCES:

LINEAR:

ANGULAR:

FINISH: DEBURR AND

BREAK SHARP

EDGES

NAME SIGNATURE DATE

MATERIAL:


TITLE:

DWG NO.


A1

WEIGHT:

assembly_view

55°

6.7

5

9.1

750

0.0

75

1.00 A

A

B

F

90°

0.75 A

1.075 A

A

3.00 ±0.01

0.10 + 0.020.00

11.80 ±0.05

0.10 + 0.020.00

3.00 ±0.01

0.1

38 + 0

.012

0.0

00

8.9

36 + 0

.014

0.0

00


A A

B B

C C

D D

E E

F F

G G

H H

J J

K K

L L

M M

16

16

15

15

14

14

13

13

12

12

11

11

10

10

9

9

8

8

7

7

6

6

5

5

4

4

3

3

2

2

1

1

DRAWN

CHK'D

APPV'D

MFG

Q.A



SURFACE FINISH:

TOLERANCES:

LINEAR:

ANGULAR:

FINISH: DEBURR AND

BREAK SHARP

EDGES

NAME SIGNATURE DATE

MATERIAL:


TITLE:

DWG NO.


A1

WEIGHT:

assembly_view

55°

6.7

5

9.1

750

0.0

75

1.00 A

A

B

F

90°

0.75 A

1.075 A

A

3.00 ±0.01

0.10 + 0.020.00

11.80 ±0.05

0.10 + 0.020.00

3.00 ±0.01

0.1

38 + 0

.012

0.0

00

8.9

36 + 0

.014

0.0

00


A A

B B

C C

D D

E E

F F

G G

H H

J J

K K

L L

M M

16

16

15

15

14

14

13

13

12

12

11

11

10

10

9

9

8

8

7

7

6

6

5

5

4

4

3

3

2

2

1

1

DRAWN

CHK'D

APPV'D

MFG

Q.A



SURFACE FINISH:

TOLERANCES:

LINEAR:

ANGULAR:

FINISH: DEBURR AND

BREAK SHARP

EDGES

NAME SIGNATURE DATE

MATERIAL:


TITLE:

DWG NO.


A1

WEIGHT:

assembly_view

R0.2

25

R2.00

7.08

R0.06

R0.6

0

R0.2

25

0.50

A

.01 F

.01 B

11.8

0

8.65

11.0

0

C

D

R0.125

0.30

DETAIL ASCALE 10 : 1

.01 E

0.2

5

0.3

5

0.08

R0.0

1

0.30

DETAIL CSCALE 5 : 1

.01 D

D

E

A A

B B

C C

D D

E E

F F

G G

H H

J J

K K

L L

M M

16

16

15

15

14

14

13

13

12

12

11

11

10

10

9

9

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8

7

7

6

6

5

5

4

4

3

3

2

2

1

1

DRAWN

CHK'D

APPV'D

MFG

Q.A



SURFACE FINISH:

TOLERANCES:

LINEAR:

ANGULAR:

FINISH: DEBURR AND

BREAK SHARP

EDGES

NAME SIGNATURE DATE

MATERIAL:


TITLE:

DWG NO.


A1

WEIGHT:

DRAWER

R0.2

25

R2.00

7.08

R0.06

R0.6

0

R0.2

25

0.50

A

.01 F

.01 B

11.8

0

8.65

11.0

0

C

D

R0.125

0.30


.01 E

0.2

5

0.3

5

0.08

R0.0

1

0.30

DETAIL CSCALE 5 : 1

.01 D

D

E

A A

B B

C C

D D

E E

F F

G G

H H

J J

K K

L L

M M

16

16

15

15

14

14

13

13

12

12

11

11

10

10

9

9

8

8

7

7

6

6

5

5

4

4

3

3

2

2

1

1

DRAWN

CHK'D

APPV'D

MFG

Q.A



SURFACE FINISH:

TOLERANCES:

LINEAR:

ANGULAR:

FINISH: DEBURR AND

BREAK SHARP

EDGES

NAME SIGNATURE DATE

MATERIAL:


TITLE:

DWG NO.


A1

WEIGHT:

DRAWER

R0.2

25

R2.00

7.08

R0.06

R0.6

0

R0.2

25

0.50

A

.01 F

.01 B

11.8

0

8.65

11.0

0

C

D

R0.125

0.30


.01 E

0.2

5

0.3

5

0.08

R0.0

1

0.30

DETAIL CSCALE 5 : 1

.01 D

D

E

A A

B B

C C

D D

E E

F F

G G

H H

J J

K K

L L

M M

16

16

15

15

14

14

13

13

12

12

11

11

10

10

9

9

8

8

7

7

6

6

5

5

4

4

3

3

2

2

1

1

DRAWN

CHK'D

APPV'D

MFG

Q.A



SURFACE FINISH:

TOLERANCES:

LINEAR:

ANGULAR:

FINISH: DEBURR AND

BREAK SHARP

EDGES

NAME SIGNATURE DATE

MATERIAL:


TITLE:

DWG NO.


A1

WEIGHT:

DRAWER

Validation

Design FMEA

Itemand

Function

Potential Failure Mode

Potential Effects of Failure

SEVPotential Cause(s)

or Failure Mechanism(s)

OCCCurrent Design

ControlsRecommended

Action(s)

Linear damper: dampens motion of drawer door

Damper fails and drawer swings open quickly

• Contents of glovebox can spill out

• Glovebox drawer crashes onto knees

++Hydraulic fluid leaks out of damper

Limited to life cycle of damper

Part is purchased fromreputable distributor

Conduct furtherresearch and testing on damper specs

Damper becomes dislodged

• Unrestrictedmotion

• Damper could fall into dashboard interior

+

Extreme rattling could cause damper to travel over lip

Further researchneeded

Damper is interference-fit over retaining boss

Ensure that pathin event of falldoes not lead to void in dashboard

Latch: allows user to open gloveboxdrawer

Handle fails to trigger latch operation

• Items like insurance + registration unreachable

• Space becomes unusable

+++

Latch separatesfrom handle due to excessive force while in closed position

Unlikely None

Performmechanicalanalysis on latchto determine F.S.

Latch retainer:captures latch when drawer is closed

Latch retainer fails or dislodges from dashboard

• Glovebox drawer can no longer close

+

User pulls drawer open without grasping handle to release latch

Potential to occurevery time drawer isoperated

Latch retainer has beendesigned to maximizemoment of inertia aboutfailure rotational axis

Perform FEA on the latch/retainersystem

Tolerance AnalysisDescription Mean Tolerance T-squared

Drawer width 1 -11.8 0.05 0.0025Gap 1 -0.1 0.02 0.0004Dash width 1 -3 0.01 0.0001Assembly width 18 0.05 0.0025Dash width 2 -3 0.01 0.0001

Gap (*sqrt) 0.1 0.14 0.075*

min maxRSS 0.025 0.175

• Evaluating the gap between the drawer and dash assembly

• Further inquiry

• Monte Carlo Simulation

• Visualizing results

55°

6.7

5

9.1

750

0.0

75

1.00 A

A

B

F

90°

0.75 A

1.075 A

A

3.00 ±0.01

0.10 + 0.020.00

11.80 ±0.05

0.10 + 0.020.00

3.00 ±0.01

0.1

38 + 0

.012

0.0

00

8.9

36 + 0

.014

0.0

00


A A

B B

C C

D D

E E

F F

G G

H H

J J

K K

L L

M M

16

16

15

15

14

14

13

13

12

12

11

11

10

10

9

9

8

8

7

7

6

6

5

5

4

4

3

3

2

2

1

1

DRAWN

CHK'D

APPV'D

MFG

Q.A



SURFACE FINISH:

TOLERANCES:

LINEAR:

ANGULAR:

FINISH: DEBURR AND

BREAK SHARP

EDGES

NAME SIGNATURE DATE

MATERIAL:


TITLE:

DWG NO.


A1

WEIGHT:

assembly_viewSource: Visualising the Impact of Tolerances on Cosmetic Product Quality (2001), Juster et al.

F = 50 lbs.

Displacement

F = 50 lbs.

Stress

Stress

F = 50 lbs.

F = 200 lbs.

F.S. = 2.5

Stress

F = 200 lbs.

Stress Flow

Bill of Materials

Item Description Quantity Cost

Glovebox drawer Injection-molded self-extinguishingpolypropylene

1 $3.30

Suede trim for drawer interior

220 square in. $1.45

Leather trim for drawer exterior

150 square in. $6.27

3M 1099 adhesive ¼ oz. x 2 $0.60

Tooling Per 10,000 units $8.57

Linear Damper Speed limiter for motion of drawer; sold by McMaster-Car

1 $40.84

Piano hinge Controls x and y-axismotion of drawer

1 $1.48

#4 Fasteners For attaching piano hinge to drawer and dashboard

10 $1.40

Total $63.91

Target Measurement

Description Target Realized

Drawer Volume 6-8 L 7.37 L

Flush .15 .06

Gap .15 .1

Time to open 5 5.3

Price $66.25 $63.91

• Objective vs. subjective criteria

• Further testing

• User experience

• Prototyping

• Durability

Final mass: 1.5 kg

Questions?