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tweaking components

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xalxanderx

Mechanical
Jan 26, 2005
5
I am currently attempting to animate a single cylinder engine consisting of a piston, connecting rod, and crankshaft. Animating the piston and the crank is no problem, but im clueless concerning the connecting rod. Im having trouble figuring out how to animate the connecting rod because it has linear displacement simultaneous to the piston, but also rotational movement simultaneous to the crankshaft. If anybody can assist i would greatly appreciate it.
 
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I just made a 6 cyl inline and it spinning all 6. Here's what you do. Use concentric mates for the crank and piston pins. Create working planes at the midpoints of everything and mate those coincident to keep everything lined up properly. I hope I can explain the next part clearly. It makes sense once you do it, but not before. You will be "driving" a constraint to animate the assembly. Create a thin extruded cut on the end of the crank. Create another one on the housing right above it. Use an angle constraint of 0 between the two "slits". Right click on the constrain in the tree and select "drive constraint". Set starting angle at 0 and finish at 360. There are some more option boxes to control number of reps and speed, etc. You will have no trouble figuring them out. You can even record the animation from here. Let me know if this helps. Fire back if I lost you on something. Driving an angle constraint makes little sense until you have done it. You can also use any two straight edges if you have them without cutting slits.

Anyone can be Captain in a calm sea.
 
Hey i tried your advice, but i just got totally lost. If you can still help me out, that would be great. But if not then its okay, i appreciate your help.
 
I've been away. If you would like, post a specific stage of your progress, and the problem you are having and I will try and walk you through it. A few key guidelines: when builing a new part, remember to include a work plane at the midpoint based on how it will assemble to the part it connects to. It is easier to align these mid planes than create constraints base on distances.For instance the piston will have a midplane between the holes for the connecting rod pin. The connecting rod pin will have a midplane that aligns coincident with the piston mid plane. Add a concentric constraint and the pin is ready. Now add a midplane to the connecting rod. Align that coincident with the connecting rod micplane. Add a concentric constraint. Is it making sense yet?

Anyone can be Captain in a calm sea.
 
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