Continue to Site

Welcome to MCAD Central

Join our MCAD Central community forums, the largest resource for MCAD (Mechanical Computer-Aided Design) professionals, including files, forums, jobs, articles, calendar, and more.

Register Log in

Model of Oring in Round and Oval Groove?

M

morsetaper2

New member
I was wondering if anyone knows how I could model the same oring part, as a circle (its free state), and in an ovel shape? I'm not talking about the x-section. I'd like to be able to model an oring as it would lie in a groove that is circular. And a groove that is racetrack (or oval) shaped.

Would this be possible using flexible componets? If yes, how? Or have another way to do it?

Thanks, mark
 
morsetapper2,

just playing around with ideas: it is possible using conic arcs instead of a plain circle. I made a datum sketch and then a sweep protrusion using the sketch as a trajectory. I can then shift the values of the sketch to produce shapes other than round. For instance I can change the rho of the arc from .5 to .7, or the distance from the center to pull in a side. Using this should allow you to make these dimensions flexible and make any shape you need.

cheers,

M
 
Actually when it's installed the o'ring looks like figure 1 but when pressure is applied looks like figure 2.


View attachment 3384


I have a O'ring handbook from where I get the dimensions for grooves etc. And as for the o'ring I model it in free state asa circle. This is enough for me but if you really want to make it like it actually looks then have a look at this handbook maybe it will help you with something.


And like Magneplanar said you can make it with a sweep with conic arc, but if you don't care about the dimensions in working conditions then you could make a spline for the x-section.


If you need for the O'ring to change it's shape as the groove changes then make the o'ring with circle, oval or whatever shape you need to be, then assemble the o'ring, then in your assembly go to model tree and redefine the O'ring sketch section directly in the assembly. And constraint the oring section to the groove walls. Now the O'ring will have assembly references to the groove and will change if the groove changes.


But I would do this only if you need to.
 
You can download this for free from http://www.epm.com/, I tried it now and it seams the download is not active so if this happens to you too, then copy all 8 archive in one directory and then click on the first one and hit extract.


2007-04-10_235620_epm_oring_handbook.part01.rar


feel free to scan it for viruses, at the end should be a .pdf file
smiley2.gif



Added later:


[url]http://www.sharebigfile.com/file/140738/epm-oring-handbook-p df.html[/url]


Use which link you prefer.
Edited by: vlad1979
 
I am sorry for all these posts but I did not wanted to start yet another topic like those with send it to me, too...., give me, give me, give me......
smiley2.gif
 
Another method is to use Envelope parts in your assembly.
In a simplified assy you can substitute a part (your circular O-ring) with an envelope part (your own shaped O-ring).
 
Thanks for the replies but I don't think you understood what
I was asking. I am not concerned about the compressed state of the orings
x-section. I am talking about its sweep trajectory in 2 different grooves.



Example: I'm using an oring in 2 face seal configurations (two different groove
shapes). Your typical face seal groove is circular in shape. In my
assembly I have the same oring p/n occuring in 2 locations, two different
groove shapes, 1 circular, and 1 racetrack shaped.



loc #1 it is a face seal, the groove is circular, sealing a round fluid tube.



loc #2 the groove is a racetrack shape (rectangular w/ radiused corners),
sealing an electric feed thru plate rectangular hole.



Like the shapes here:



http://www.parker.com/o-ring/Literature/March%202004%20(Ra cetrack%20grooves).pdf



I was wondering if flexible components would allow me to have the same p/n
oring represented as two different shapes for each groove, yet fall out on the
BOM as the same p/n.



If this is possible, some direction would be appreciated. I searched for envelope parts but I don
 
morsetaper2,

what I described previously would allow variable shapes such as oval or round for the o-ring overall shape. The sweep I was describing is the centerline of the o-ring, although you could also change the shape of the o-ring cross section itself. I will make an example later. If you have this in an assembly you can use one part number and call it out in your BOM as such. If it is flexible then the shape can conform to the racetrack by varying the values. You should be able to match the parker guide line of the centerline circumference of the track being equal to the centerline circumference of the o-ring.

cheers,

M
 
examples of modified sketch trajectories for the same o-ring to show what could be controlled as a flexible component:

Round
View attachment 3388

Racetrack
View attachment 3389

You should be able to tweak the numbers to fit into a variety of grooves such as a regular o-ring would fit into. For more complicated shapes you can add in additional conic arcs. You can also add in some control features that could interface with the shape of the groove in the assembly for easier flexible component control.

cheers,

M
 
magneplanar said:
examples of modified sketch trajectories for the same o-ring to show what could be controlled as a flexible component:

Round
View attachment 3393

Racetrack
View attachment 3394

You should be able to tweak the numbers to fit into a variety of grooves such as a regular o-ring would fit into. For more complicated shapes you can add in additional conic arcs. You can also add in some control features that could interface with the shape of the groove in the assembly for easier flexible component control.

cheers,

M
Click to expand...
Nicely done. You can also change the cross section to show the deformed state at the same time. If you really want to get picky you should write relations to keep the volume constant as the part is stretched and compressed.
 
thanks for the comments on my idea...I like that we can see different approaches and add to the methods we use and see new processes for accomplishing tasks.

that envelope thing is nice too, I can sure see the value in improving my use of relations and flexible components to make the design less cumbersome. I spend too much time hand editing what should be an automated action.

more than one way to skin a cat? I have no idea who came up with that phrase haha

cheers...

M
 
You must log in or register to reply here.

Sponsor

Articles From 3DCAD World

Back
Top