Mechatronic Modeling: Pretensioner Mechanism

Simulation Analysis as part of a Retractor Mechanism.

04/19/2006

Guillermo Cazares

Presentation Content

• Background Information

• Functional Analysis

• Simulation Analysis

• Results

• Conclusion

Problem Statement

• Analyze the performance of Pretensioner Mechanism as part of a retractor assembly in a seat belt system.

• Transfer of Pressure over the piston.• Transfer of torque to belt and determine

the length of belt.Note: The requirement is that 80mm of

belt must be pulled into spool in 12ms.(Beside packaging and weight requirements)

Background Information

• Components of a Seatbelt System

Retractor

Buckle and Latch

Belt

Height Adjuster

Anchor

Front View of a Passenger Side Seat Belt System Schematic

Background Information

Background Information

Belt

Pretensioner Unit

Retractor Assembly

Locking Mechanism

Background Information

Gas generator

Hub

Pinion

Gearwheel

Shaft

Spring

Cover

Housing

Roller

O-Ring

Assembly Vent

Tube

Damper

Piston

Background Information

Schematic Diagram

Signal From CU

Igniter Fires Propeller & Pressurizes the Chamber

Piston Movement

Pinion & Gear Wheel Rotates

Hub Rotates

Rollers Engage Hub to rotate Spool

Spool Pulls In Webbing

1

OneJunction5

TFTF5

Integrate1

1Spool

MSeMSe1

TFTF4

I

I4

TFTF3SignalGenerator1

I

I3

I

I2

1Hub

TFTF2

I

I1

1Gear_Wheel

TFTF1

1Piston

Bond Graph

Transformer 1

Hydraulic Power to Mechanical Translation Power

Transformer 2

Mechanical Translation Power to Mechanical Rotational Power

Transformer 3

Mechanical Rotational Power.

Transformer 4

Mechanical Rotational Power.

Resultsmodel

0 0.005 0.01 0.015 0.02time {s}

0

0.05

0.1

0.15

0.2 output {m}

Comparison Results

Resultsmodel

0 0.005 0.01 0.015 0.02time {s}

0

10

20

30

40

50

60

70

p1.f {m/s}

model

0 0.01 0.02 0.03 0.04time {s}

0

20

40

60

80

100 p.e {N}

model

0 0.005 0.01 0.015 0.02 0.025 0.03 0.035time {s}

0

200

400

600

800

1000

1200

1400p.e {N.m}

Torque at the Spool

Speed of Piston

Force at the Piston

Further Simulationmodel

0 0.005 0.01 0.015 0.02 0.025time {s}

-0.5

0

0.5

1

1.5

2

2.5 output {m}

Radius of 25 mm

Conclusion

•The simulation used did give us the expected results expect that I had to remove some of the unknown R and C elements that in reality are present in the system.• At the same time the model provided useful information that is very difficult and costly to attain.• It allows you to gain knowledge of the behavior of a system with simple click of a button.

Questions?

• Thank you for your Attention