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

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

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.

Results

Comparison Results

Results Torque at the Spool Speed of Piston Force at the Piston

Further Simulation 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