help with joints

[lornemartin]

I have a design here that I would like some feedback on.

When I turn the crank, I would like the piston block to move back and forth, and the piston to slide up and down within the piston block. I created two motion links (now suppressed) that sort of do what I want to do, but they are obviously limited to a quarter revolution because then the direction needs to change.  PinSlot41 and Rev42 I think would do what I want to do, but I can't seem to be able to activate them without causing other issues.  Is there a way to simulate what I'm trying to see, or is this a limitation of the software?

[innovatenate]

What are the issues that occur when you activate the Motion Links? A Screencast recording might help shed light on the topic.

Otherwise, could you share an archive file of this design? Go to the Export command from the main menu to save the an archive file (*.F3D format) to your local machine. After this, zip the file and attach it to this forum thread.

Thanks,

[lornemartin]

Sorry, I'm still learning this fusion thing. The words "design here" in my original post are a link to download the project.  Or does that not work for you? Here is the link again.

[innovatenate · Accepted solution]

I apologize for the confusion. I missed the hyperlink in your first post. I suspect you are looking for a Motion Study. The assembly joints themselves should be adequate to get the motion you're looking for. Take a look at the below file and let me know what you think. Hopefully, I haven't misunderstood your intent.

https://myhub.autodesk360.com/ue29c8e8f/shares/public/SH7f1edQT22b515c761e5a1fe6ee375334c5

I hope that helps, let me know either way!

Thanks,

[lornemartin]

Thanks, that is exactly what I wanted to see.  But I'm still not quite clear on what I was doing wrong. I understand that I don't need the motion links. But why didn't my assembly constraints work?  Was there some automatic constraining going on when I created the parts dependant on each other's geometry that you took out?  I notice that I had the piston as a subcomponent of the piston block, and you changed that. Was that necessary to make it work? Or is the motion study needed to make it work?

[innovatenate]

There were some redundant joints in the model. Due to the exisiting geometry of the model, some of the joint types were not really necessary.  

PinSlot41 was applied between the Crank and the Piston Block body (in the original file I believe). PinSlot41 was not necessary, so delete that one.  I applied a cylindrical constraint between the Piston Cylinder and the crank. You may convert Rev42 from a revolution joint to a cyindrical joint. Also, Slider2 could also be converted to a cylindrical joint type. This should allow you to work with the model.

To make it easy on myself, I just started from as close to scratch as possible. I may have re-organized the browser some in the process; however, it is possible to have components in a subassembly with joints move. I've created a sample 4-bar linkage file (below) to illustrate this (below). 

https://myhub.autodesk360.com/ue29c8e8f/shares/public/SH7f1edQT22b515c761e9906b5a3ec330a97

I hope this helps. Let me know if you have any other questions.

Thanks,

[lornemartin]

Yes, I found those redundant joints, I should have posted that. Thanks for your help.

Regards,
Lorne Martin CNC Programming and Setup
Horst Welding Tel: (866) 567-4162 / Fax: (519) 291-5388 / www.horstwelding.com
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