I designed a snapin pulley using some pulley I found online but I am not satisfied with the dimensions of the tooth profile. I have gathered information regarding how the tooth profile should be, but I am missing some information. Hope you guys can help me complete it.
I only started really learning CAD and stuff a few weeks ago lol. I am probably wrong.
What are the exact dimensions of the individual tooth.
According to picture from the Gates manual, each tooth has to be 1.93mm high right? Can’t you just make and pattern that shape since we will probably use Gates belts?
What is the position of the belt pitch line relative to the bottom of the tooth.
Isn’t the belt Pitch line the same thing as the height of the belt? So 3.81mm from the bottom of the tooth to the belt pitch line…
I think I asked more questions than I answered…
Not understanding what you’re trying to do exactly, but I would try a program called CamBam. It has a tool that will make you the profile for any tooth count you want.
All of the images i found doesn’t show the distance from the primitive circumference to the root of the tooth, for my 3d printed pulley i printed several small slices of the pulley until i found one that fits
Maybe using CamBam that @rpn314 suggested you can export the profile to your cad software and get the measurements
EDIT: Thanks a lot @rpn314, worked flawlessly, finally the correct profile
The issue with these profiles is that they are showing you what the distance between teeth are on a flat section of the belt. Once the belt meshes with the tooth it is no longer straight and the center to center distance is actually the arc length of the segment of the pitch diameter between two teeth. I’m on my phone at the moment but once I get to my home computer later tonight I can upload the profile I use for a singular tooth then pattern to create any sized pulley
This 's almost exactly the same numbers that mine had. I dimensions mine different to allow for changing the number of teeth and keeping other relationships intact. @mishrasubhransu
I agree, this is not how I would draw, I just imported the profile and put the main dimensions so people can use then as base to draw any teeth count
My plan is to get some pulleys made from wire EDM since I can only find aluminum pulleys around here and they are experiencing significantly wear, but no point using EDM with a profile that is not exact
So you can use the 10 Degrees for 36T or you can do what I do which is create the tooth profile and dimension the width of one tooth to 4.898mm. The two lines coming out from the center of the 25.83 circle and meeting the radius are normal to the radius and I set a geometric constraint there. You have to then set the rest of the geometric constraints to the profile, like the tangent intersects between the .458 radius and the 1.543 and the short segment connecting the .458 radius to the lines coming out of the center is actually a straight line, there’s no arc. Its so short it wont matter. You can then circular pattern the one tooth slice as many times as you want and then select the corners and coincide them and you can create a pulley with any number of teeth.
This works great for commonly available sizes bur for example, 42T HTD5 does not exist commonly, you will have a hard time trying to find that online. Its quicker to create that yourself. Also, you can create odd numbered pulleys as well which also do not exist.
to calculate the pitch diameter you can just multiply pitch of the belt with the tooth count of the pulley and divide it by pi.
for 40t HTD 5m this wil be (40*5)/3.14… =63.66mm diameter
Thanks everyone. The cambam profile didn’t seem accurate enough. I got the actual part from the manufacturer website which @Kaly mentioned and made my profile sketch like @JuniorPotato93 suggested. Made it match the original part as close as possible. Once the profile is done then it’s just a matter of using it for different number of teeth.
@mishrasubhransu
How do you calculate the OD and U values?
You calculate the U value from subtracting PD and OD, but then you use that U value to calculate OD?
@JuniorPotato93 Hi I don’t really understand your instructions about creating a pulley, I’m trying to make a really bit 188 T pulley and I printed one but it just doesn’t seem to fit. Maybe I am misunderstading your instructions?.
I don’t get why the 25.83mm is higher than the 27.464 in your diagram
from here
