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constraining a cam

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Message 1 of 12
Anonymous
359 Views, 11 Replies
‎03-17-2003 06:12 AM
‎03-17-2003 06:12 AM

constraining a cam

I am trying to constrain a camshaft and can only get it to work partially. The cam is rotating and it needs to move a pushrod up and down much like a pushrod for a valve assembly in an engine. When I choose transitional constraint, it will only let me choose one of the cam's surfaces. It follows that one face, but stops when the radius of the cam changes. I would like it to go up and down and follow the entire outer surface of the cam. I've had no luck, any advice is appreciated...thanks.
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Message 2 of 12
Anonymous
in reply to: Anonymous
‎03-17-2003 06:16 AM
‎03-17-2003 06:16 AM

It has been a long time since I have done this, so correct me if I am wrong.
I think if you pick the face of the came that contains the profile of the
cam , it will work better for you.

--
Cory McConnell
BJ pipeline Inspection
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Message 3 of 12
Anonymous
in reply to: Anonymous
‎03-17-2003 06:25 AM
‎03-17-2003 06:25 AM

I have tried that and it didn't work. It seems like it should though.
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Message 4 of 12
Anonymous
in reply to: Anonymous
‎03-17-2003 02:03 PM
‎03-17-2003 02:03 PM

Usually, you need to have only enough freedom to allow the follower to
follow the surface. If the Cam Follower's radius is such that it would
be smaller than the surface of the cam, like on an inside curve, it can
stop as well. Consider creating a surface only cam and constraining the
follower to that surface. If it works, use it and turn off the
surface's visibility. If the surface is the same shape as the cam, no
one will know that it is not following the cam itself.

dwpbemis wrote:

> I am trying to constrain a camshaft and can only get it to work
> partially. The cam is rotating and it needs to move a pushrod up and
> down much like a pushrod for a valve assembly in an engine. When I
> choose transitional constraint, it will only let me choose one of the
> cam's surfaces. It follows that one face, but stops when the radius of
> the cam changes. I would like it to go up and down and follow the
> entire outer surface of the cam. I've had no luck, any advice is
> appreciated...thanks.
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Message 5 of 12
Anonymous
in reply to: Anonymous
‎03-18-2003 02:10 AM
‎03-18-2003 02:10 AM

Try to make use of a round ball.
See CF.

Christian.

PS. Have you tried designing the cam in MDT? Look at:
http://www.avat.com/training/elearning/techtips_action.asp?sgid=4#


> > I am trying to constrain a camshaft and can only get it to work
> > partially. The cam is rotating and it needs to move a pushrod up and
> > down much like a pushrod for a valve assembly in an engine. When I
> > choose transitional constraint, it will only let me choose one of the
> > cam's surfaces. It follows that one face, but stops when the radius of
> > the cam changes. I would like it to go up and down and follow the
> > entire outer surface of the cam. I've had no luck, any advice is
> > appreciated...thanks.
>
>
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Message 6 of 12
Anonymous
in reply to: Anonymous
‎03-18-2003 04:01 AM
‎03-18-2003 04:01 AM

Hi,

I've struggled some time with a crankshaft cam of a
4-stroke model engine, that didn't drive by constraint. Meanwhile I've detected
my fault:

The moving contours are critical. You must avoid
point contact, or edge pressure between the moving surfaces.

 

I've put a moving example to CF. It can be driven
with KW-Drehung of part YS2620.

 

Now change Fillet1 of YS0675 to 0.5mm. It refuses
to move the whole way. The reason is, that the contact area moves thus to the
edge of the cylinder of YS0675.

Same influence can be seen by changing the contact
zone of YS2660.

 

Regards

Walter 

 


style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
I
am trying to constrain a camshaft and can only get it to work partially. The
cam is rotating and it needs to move a pushrod up and down much like a pushrod
for a valve assembly in an engine. When I choose transitional constraint, it
will only let me choose one of the cam's surfaces. It follows that one face,
but stops when the radius of the cam changes. I would like it to go up and
down and follow the entire outer surface of the cam. I've had no luck, any
advice is appreciated...thanks.
Report
0 Likes
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Message 7 of 12
Anonymous
in reply to: Anonymous
‎03-18-2003 05:22 AM
‎03-18-2003 05:22 AM

I only see failures of the transitional constraint
on your file? If the cam followers were radiused then it would work
fine.


--
Laurence,
  
Power is nothing without
Control
---
        


style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">

Hi,

I've struggled some time with a crankshaft cam of
a 4-stroke model engine, that didn't drive by constraint. Meanwhile I've
detected my fault:

The moving contours are critical. You must avoid
point contact, or edge pressure between the moving surfaces.

 

I've put a moving example to CF. It can be driven
with KW-Drehung of part YS2620.

 

Now change Fillet1 of YS0675 to 0.5mm. It refuses
to move the whole way. The reason is, that the contact area moves thus to the
edge of the cylinder of YS0675.

Same influence can be seen by changing the
contact zone of YS2660.

 

Regards

Walter 

 


style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
I
am trying to constrain a camshaft and can only get it to work partially. The
cam is rotating and it needs to move a pushrod up and down much like a
pushrod for a valve assembly in an engine. When I choose transitional
constraint, it will only let me choose one of the cam's surfaces. It follows
that one face, but stops when the radius of the cam changes. I would like it
to go up and down and follow the entire outer surface of the cam. I've had
no luck, any advice is
appreciated...thanks.
Report
0 Likes
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Message 8 of 12
Anonymous
in reply to: Anonymous
‎03-18-2003 05:42 AM
‎03-18-2003 05:42 AM

The only way I could get it to work was by cheating and adding a barrel
section ( 0.001mm deep as to appear as a circular line on ball ) to the ball
and then using transitional constraint.

--
Laurence,

Power is nothing without Control
---


"Christian Niemarkt" wrote in message
news:4EF9E31358FFCBC071E6D4CF451DD1BF@in.WebX.maYIadrTaRb...
> Try to make use of a round ball.
> See CF.
>
> Christian.
>
> PS. Have you tried designing the cam in MDT? Look at:
> http://www.avat.com/training/elearning/techtips_action.asp?sgid=4#
>
>
> > > I am trying to constrain a camshaft and can only get it to work
> > > partially. The cam is rotating and it needs to move a pushrod up and
> > > down much like a pushrod for a valve assembly in an engine. When I
> > > choose transitional constraint, it will only let me choose one of the
> > > cam's surfaces. It follows that one face, but stops when the radius of
> > > the cam changes. I would like it to go up and down and follow the
> > > entire outer surface of the cam. I've had no luck, any advice is
> > > appreciated...thanks.
> >
> >
>
>
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Message 9 of 12
Anonymous
in reply to: Anonymous
‎03-18-2003 05:53 AM
‎03-18-2003 05:53 AM

Hmm, Laurence

I've realized, that it's not moving with
my IV6 SP2. But I've seen it moving...

 

Where? I'm not allowed to talk about ...
;-)

 

Walter

 


style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">

I only see failures of the transitional
constraint on your file? If the cam followers were radiused then it would work
fine.


--
Laurence,
  
Power is nothing without
Control
---
        


style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">

Hi,

I've struggled some time with a crankshaft cam
of a 4-stroke model engine, that didn't drive by constraint. Meanwhile I've
detected my fault:

The moving contours are critical. You must
avoid point contact, or edge pressure between the moving surfaces.

 

I've put a moving example to CF. It can be
driven with KW-Drehung of part YS2620.

 

Now change Fillet1 of YS0675 to 0.5mm. It
refuses to move the whole way. The reason is, that the contact area moves
thus to the edge of the cylinder of YS0675.

Same influence can be seen by changing the
contact zone of YS2660.

 

Regards

Walter 

 


style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
I
am trying to constrain a camshaft and can only get it to work partially.
The cam is rotating and it needs to move a pushrod up and down much like a
pushrod for a valve assembly in an engine. When I choose transitional
constraint, it will only let me choose one of the cam's surfaces. It
follows that one face, but stops when the radius of the cam changes. I
would like it to go up and down and follow the entire outer surface of the
cam. I've had no luck, any advice is
appreciated...thanks.
Report
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Message 10 of 12
Anonymous
in reply to: Anonymous
‎03-18-2003 06:03 AM
‎03-18-2003 06:03 AM

That's OK ;^)....mums the word


--
Laurence,
  
Power is nothing without
Control
---
        


style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">

Hmm, Laurence

I've realized, that it's not moving with
my IV6 SP2. But I've seen it moving...

 

Where? I'm not allowed to talk about ...
😉

 

Walter

 


style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">

I only see failures of the transitional
constraint on your file? If the cam followers were radiused then it would
work fine.


--
Laurence,
  
Power is nothing without
Control
---
        



style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">

Hi,

I've struggled some time with a crankshaft
cam of a 4-stroke model engine, that didn't drive by constraint. Meanwhile
I've detected my fault:

The moving contours are critical. You must
avoid point contact, or edge pressure between the moving surfaces.

 

I've put a moving example to CF. It can be
driven with KW-Drehung of part YS2620.

 

Now change Fillet1 of YS0675 to 0.5mm. It
refuses to move the whole way. The reason is, that the contact area moves
thus to the edge of the cylinder of YS0675.

Same influence can be seen by changing the
contact zone of YS2660.

 

Regards

Walter 

 


style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
I
am trying to constrain a camshaft and can only get it to work partially.
The cam is rotating and it needs to move a pushrod up and down much like
a pushrod for a valve assembly in an engine. When I choose transitional
constraint, it will only let me choose one of the cam's surfaces. It
follows that one face, but stops when the radius of the cam changes. I
would like it to go up and down and follow the entire outer surface of
the cam. I've had no luck, any advice is
appreciated...thanks.
Report
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Message 11 of 12
Anonymous
in reply to: Anonymous
‎03-18-2003 10:21 AM
‎03-18-2003 10:21 AM

Not sure if this is what you are looking for but...



There is a zip file in CF called "CAM".



Unzip, open the assembly, select the component called "cam" select the "angle" constraint, Select "drive constraint", click the "forward (or reverse)" button, and watch the cam turn and see the push rod move.



Not very fancy, but not too bad for a 15 minute creation.



Regards,



Don A 🙂
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Message 12 of 12
Anonymous
in reply to: Anonymous
‎03-18-2003 09:08 PM
‎03-18-2003 09:08 PM

See CF for a sample workaround, transitional constraints are picky perhaps
7.0 will be better. That's all folks!

--
Laurence,

Power is nothing without Control
---


"Christian Niemarkt" wrote in message
news:4EF9E31358FFCBC071E6D4CF451DD1BF@in.WebX.maYIadrTaRb...
> Try to make use of a round ball.
> See CF.
>
> Christian.
>
> PS. Have you tried designing the cam in MDT? Look at:
> http://www.avat.com/training/elearning/techtips_action.asp?sgid=4#
>
>
> > > I am trying to constrain a camshaft and can only get it to work
> > > partially. The cam is rotating and it needs to move a pushrod up and
> > > down much like a pushrod for a valve assembly in an engine. When I
> > > choose transitional constraint, it will only let me choose one of the
> > > cam's surfaces. It follows that one face, but stops when the radius of
> > > the cam changes. I would like it to go up and down and follow the
> > > entire outer surface of the cam. I've had no luck, any advice is
> > > appreciated...thanks.
> >
> >
>
>
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