Mate to use for a Cam

ShepRCS

Hi All

I've built Combers Rotary engine which uses a Cam to create rotary motion.  It appears circular although it is not quite.

I don't think that there is a Mate/Relation I can apply that will make the engine actually work when I spin the shaft?  It would be a mate between the bearing and the cam ring or a relation between the piston and the model  like a rack and pinion but it needs to go up for 180deg and down for the rest.  Anyone with any ideas on this?

Here is a link to the model I hope (just copied the address bar from the model which I have made public)

Shep

andrew_troup

@Shep
Here's a recent post on another thread which will hopefully answer your questions

Andrew_Troup said:@Hansrudolf : You can certainly model a cam as a part very nicely in OnS. What the contributors are saying above is that (at present) there is no OnS way (or at least, no intended way) to have a non-circular cam activate a follower realistically, as it spins in an assembly model of a mechanism.

In other packages (and presumably in OnS at some future date) there is a "cam mate" which allows creating a tangent mate with a path. In some cases, the path is limited to arcs and lines, in others it can be spline-based.

An option OnS might perhaps consider, if they implement a "Fit Spline" solution (which can convert chains of arcs and lines to a single spline) would be to simplify the input options to a cam mate by accepting only splines - preferably open splines, as well as closed ones. 

andrew_troup

@Shep
Here's a recent post on another thread which will hopefully answer your questions

Andrew_Troup said:@Hansrudolf : You can certainly model a cam as a part very nicely in OnS. What the contributors are saying above is that (at present) there is no OnS way (or at least, no intended way) to have a non-circular cam activate a follower realistically, as it spins in an assembly model of a mechanism.

In other packages (and presumably in OnS at some future date) there is a "cam mate" which allows creating a tangent mate with a path. In some cases, the path is limited to arcs and lines, in others it can be spline-based.

An option OnS might perhaps consider, if they implement a "Fit Spline" solution (which can convert chains of arcs and lines to a single spline) would be to simplify the input options to a cam mate by accepting only splines - preferably open splines, as well as closed ones. 

ShepRCS

Thanks @Andrew_Troup I hadn't seen that thread.  Answers my question perfectly.  Just wanted to make sure that I wasn't missing an obscure use of something we already had!

Waiting on Cam Mate then!

Shep

kesava_prasad_t_d

Eagerly awaiting a cam/path mate from OnShape.

Stuart_Tod

@richard_55 , @kesava_prasad_t_d ,

There is a post in the Improvement Request section for completion of the Mates Suite, including Cam. Head on over there and vote it up!