saurabhr202 Posted March 17, 2009 Share Posted March 17, 2009 Hi ... I am doing a project on rack and pinion gear wherein i have to perform cosmos motion analysis on rack and pinion gear....can you please help me from where could i get a tutorial for this.... Quote Link to comment Share on other sites More sharing options...
shift1313 Posted March 17, 2009 Share Posted March 17, 2009 there are several posts in this forum about it, here is one http://www.cadtutor.net/forum/showthread.php?t=31599 I put a few screen shots in there on the second page and there are a few zip files of animations. The most important thing is you need to be in a motion study(drop down box, bottom study). and you cant have mechanical constraints before you are there. You need to be able to rotate your gears around in model space but the contact constraint will be done in the motion study(if you are looking for things like contact forces). If that post doesnt help you out let me know Quote Link to comment Share on other sites More sharing options...
saurabhr202 Posted March 18, 2009 Author Share Posted March 18, 2009 hi ....thanx i got the contact part... also is thr any way whr you can get to know what are the forces acting on the two gears as i want to do the kinematic analysis on the rack and pinion... i got the plot between contact force for rack and pinion ...but m not able to get the other forces correctly... m I doing the kinematic part right? Quote Link to comment Share on other sites More sharing options...
shift1313 Posted March 18, 2009 Share Posted March 18, 2009 when you setup your force plot you should be able to select two faces you wish to analyze, ie one face on your rack gear and one on your pinion. When you setup the force plot you have plenty of options. Here is a screen shot. You have categories and sub categories. If you select the Force category you get several options, one is contact force. So you are saying you have the correct contact force plot but none of the others show? do you hit the calculate button again? each time you make a change you need to recalculate the simulation. There are certain selections that work or dont work depending on what you are trying to get. What are you looking to get and what are you selecting? Quote Link to comment Share on other sites More sharing options...
saurabhr202 Posted May 5, 2009 Author Share Posted May 5, 2009 big problem..... i want the rack to be fixed in such a way that when the pinion rotates, it move linearly vertically over the rack.... is thr a way? plz help Quote Link to comment Share on other sites More sharing options...
shift1313 Posted May 6, 2009 Share Posted May 6, 2009 do you have an assembly for this unit that properly constrains everything? Quote Link to comment Share on other sites More sharing options...
saurabhr202 Posted May 7, 2009 Author Share Posted May 7, 2009 yaa i got all the mates and constraint all done...only problem is i want the pinion to move over the rack(which is fixed vertically) so that vertical motion of rack takes place.....even after fixing the rack ...i get some error in the mate...... i wanted to upload my assembly so tat u can have a better look...but tis site allows only 250kb.....so can i plz get ur email id? ....or u can send me ur email id on saurabhr202@gmail.com ......i really appreciate all the help by u.... Quote Link to comment Share on other sites More sharing options...
shift1313 Posted May 7, 2009 Share Posted May 7, 2009 i just sent you an email. How large is the file? Quote Link to comment Share on other sites More sharing options...
shift1313 Posted May 11, 2009 Share Posted May 11, 2009 saurabhr i just sent you an email back. The main thing is to figure out what you want to see. The constraints placed in the modeling environment will work in an animation but they are only based on a mathmatical relation between components. For instance a 10tooth gear and a 20tooth gear. When you place a gear constraint you are telling SW that your 10t gear rotates 2x the 20t gear and the opposite direction. When you are in a Basic Motion or Motion Analysis these constraints need to(or will automatically be) suppressed because they are not valid. Rather a 3dContact (cam/rocker icon) will be added and motion will be based entirely on contact between solids. Based on this interaction SW can give you forces and other useful information from the assembly. Another note in setting up your motor applied to your pinion gear. Check direction and type of motion. With a rack/pinion setup I would set the motor parameter to distance instead of constant speed. This way you can set the rotation distance by giving an angle(720 in your case). Let me know through email or this post if you want me to clarify anything. Unfortunately my copy of SW is newer than yours so I cant save the assembly and post it or send it back. Quote Link to comment Share on other sites More sharing options...
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