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					PACE TERM PROJECT

  Alex Furse and Mike Milewski
                                                        PAC E
Project Objectives
 As Design Engineers we were responsible for the design of a deck lid
 (trunk) of a new automobile. The design criteria required was that the
 motion of the deck lid was constrained to move along a predetermined
 path. Three positions of the Deck lid were specified: 1) closed, 2)
 midpoint and 3) open.

 The assignment was to design a mechanism using Unigraphics NX-3
 Motion that will move the deck lid along a path through the three
 positions. It was assumed that the deck lid and linkage was two-
 dimensional and of negligible mass. The Deck lid cross section CAD
 geometry was provided in IGES format. Only the driver ground pivot
 was fixed.




                                                 Alex Furse and Mike Milewski
                                                           PAC E
                                                           PAC E
Project Constraints




                                                      Driver Ground
                                                      Pivot




                      Figure 1a. Initial Position


                                                    Alex Furse and Mike Milewski
                                   P ACE
                                    PE C E
                                 PAC A
Project Constraints




    Figure 1b. Middle Position   Figure 1c. Open Position




                                    Alex Furse and Mike Milewski
                            PAC E
Method of Approach




                     Alex Furse and Mike Milewski
                                                   PAC E
Research and Planning

• Brainstorming
• Researching existing hinge
  designs

                                           Figure 1a. BMW hinge.




                 Figure 1b. Alfa hinge.   Figure 1c. Plymouth hinge.
                                            Alex Furse and Mike Milewski
                                           PAC E
Concepts

• Sketching
• Alternative designs
    - Roller / track system




                              Figure 2. Roller Model

                                    Alex Furse and Mike Milewski
                                                                PAC E
Motion Analysis

•   Trial and Error
    - Physical Paper Linkages
    - Working Model 2D
    - Solid Works
    - Graphical Sketching




                                     Figure 3b. Working Model   Figure 3c. Graphical Sketching


Figure 3a. Physical Paper Linkages

                                                         Alex Furse and Mike Milewski
                                                                     PAC E
Motion Analysis
•    Analytical
       - Synthesis of Mechanism:
            Analytical Design of a Four-Bar Mechanism for Three-position
           Rigid-body Guidance

    Equation (11.7-4)
     xB1(A13nC1n + A23nS1n – xO2C1n – yO2S1n + xO2)
          + y B1(A23nC1n – A13nS1n + xO2S1n – yO2C1n + yO2)
               = A13nxO2 + A23nyO2 – ½(A13n2 + A23n2)

Using Equation (11.7-4) with the assistance of Matlab and Excel we were able
to find the various link lengths and positions.


                                                              Alex Furse and Mike Milewski
                                         PAC E
Results




          Figure 4. Perspective



                                  Alex Furse and Mike Milewski
                                               PAC E
Results




          Figure 5a. Initial Position

                                        Alex Furse and Mike Milewski
                                           PAC E
Results




          Figure 5b. Mid Position

                                    Alex Furse and Mike Milewski
                                            PAC E
Results




          Figure 5c. Open Position

                                     Alex Furse and Mike Milewski
                                            PAC E
Results




          Video 1. Open to Close Motion


                                     Alex Furse and Mike Milewski
                                                           PAC E
Optimization
• Designed to minimize the effect
 of pinching
          - bend
          - spacers
• tolerances
   link hole: + 1 thou
   pin: - 1 thou
   center to center: + 10 thou                               Figure 6b. spacer
   bends: +/- 1 degree




                                    Figure 6a. link bend

                                                    Alex Furse and Mike Milewski
                                                  PAC E
Optimization

• Trunk lid gas piston
   - damping
   - easy use: little force
    required to open trunk lid
   - multiple locations but placed
    so its following the shortest
    distance




                                     Figure 7. Piston and Truck Lid

                                           Alex Furse and Mike Milewski
                                                PAC E
Manufacturing
• Designed links so that they can
   be easily manufactured.
• material: mild steel
• 2 stage process
     - sheet metal pieces cut out
      with dye
     - stamped into shaped
• cheap process
• interchangeable: links and coupler
    link can be used for both sides


                                       Figure 8. Coupler flat

                                         Alex Furse and Mike Milewski
                                                PAC E
Improvements
• reduce sheet metal thickness
 achieved by press fitting a bushing
 in the link bosses to maintain
 contact area of pins and links and
 reduce wear
• Rubber Sock                          Figure 9a. Bushings

   - decreases wear and contact
     stress
   - damps closure position


                                        Figure 9b. link sock

                                         Alex Furse and Mike Milewski
                    PAC E
PACE Goals




             Alex Furse and Mike Milewski

				
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