【转帖】drawing a hirth type coupling

yang686526

drawing a hirth type coupling?
hi, as part of a clutch assembly i need to redo this piece:
but i need the peak and valleys to be the same, so two similar pieces can be engaged together.
i made a cilinder and the i started drawing on the top surface a 45o triangle from its center to a few mm's away of the diameter and then i did an extruded cut, after that i chamfered the walls at 20o but if i do this the peak and valleys arent the same size.
what is the proper way to draw (or to calculate) this piece?

make the neutral plane for the draft at half the cut depth.
timelord
upon reexamination, if you make the neutral plane slightly above the middle of the cut depth, the walls will come in contact before the faces close togeather so there will be no backlash, much like the real parts.
timelord  
you have 8 cuts.  position the sketch plane at the vertical middle of the cut.  draw a line from the center of the circle to the outer edge (and a little beyond).  radially pattern the line 360 degrees with 16 instances.  finish the cut with the appropriate arcs, etc., but make an oversized cut sketch so that when you place a draft angle on the cut, it doesn't short the radial edges.  then extrude cut with the draft angle.
create a ref plane at mid depth of the "tooth", and use it as the neutral plane in the draft operation. the draft will then be applied equally about the plane, and the peaks and valleys will be identical.

note to self ... submit post before answering phone ... or check for new posts before submitting.

as usual you guys rock, thank you all very much!
i will also use the trick of elevating slightly the midplane to eliminate backslash.
cheers!