Tangent line constraints

[JuanviPerea_1B]

Hi, all I want to do is add a constraint that will make the big loop snap into those 3 wheels. 

I remeber adding tangent constraints manually in Inventor (I think), but as in Fusion 360 every constraint is automatic I cant get the results I want. Any ideas? 

Picture:

3 small cilinders are wheels that move the big loop. Big loop has to be tangent to all 3 wheels, it has been designed this way so it has to fit. 

[Oceanconcepts · Accepted solution]

What workflow are you using to get the shapes? If you start with a sketch with the circles / wheels laid out, you can manually apply tangent constraints, then extrude the solids.

[JuanviPerea_1B]

What i did is the following:
-Made the loop.
-in another file i made the base with the holes for the rods where they should be to match with the loop.
-then i made the weels and rods.
-in a blank file I inserted the base, the rods and wheels, put evertything in place With revolute constraints
-import the loop and try to constrain it

Hope it makes sense

[JuanviPerea_1B]

The base geometry is right, for it I sketched the loop, then the weels and made them tangent to the loop, from there i made the holes for the rods and extruded it when i was done

[Oceanconcepts]

Yes, it does make sense. Every CAD system has it’s preferred workflows. My take is that with Fusion, it’s best practice to create assemblies as components within the same file. Not least in that parametric relationships as yet don’t apply to imported files.

I think with this sort of design, where you know you need a tangent relationship between specific elements, it’s best to define that relationship with a sketch, then go about building the parts based on the sketch. If you are in history (timeline) mode, the constraints will apply and the sketch will update if you, for instance, change the position or diameters of the wheels.

There might be a way to do this to already built parts using joints and contact sets (imagine the small wheels were gears), but it seems it would be more difficult to do it that way. I will frequently do shapes in direct modeling to brainstorm a design, then when the relationships are worked out, do a sketch to precisely define dimensions and relationships. One of the things I like about Fusion is that you can have it both ways.

[JuanviPerea_1B]

Thanks for your time Ron, I will try that workflow tomorow post the resultS. I thought that if I extruded everything directly from the sketch it would be as a solid, or 4 solids acting as one. I do need the wheels and the loop turning at different speeds. Also, Im used to draw parts in diferent files and then get everything together in assemblies, its easier to change parts that way also.
thanks

[martin.zatecka]

Hello,

I prepared the example with setup of connection and motion link. The motion link is the way how to modify aspect ratio between the wheels.

regards

Martin

[JuanviPerea_1B]

Thanks Martin, now I have the wheels and loop with joints, but the relationship between the wheel and the loop is 1:1, How can I change this?

[JuanviPerea_1B]

Okay, I did it by modifyin the angle in the motion link. I thought Fusion would do this automatically knowing the radius of both objects. 

So what I did is calc the ratio manually and then in motion link options 1 angle has 360 and the other X, which depends on the geometry.

Can this be done automatically?

[martin.zatecka]

Hello,

I'm not sure how to make gear ratio automatically. I would calculate the ratio number (diameter1 / diameter2) and multiply the angle of rotation.

It is fully under your control.

regards

Martin