Tooth Profile for HTD 5M pulley ( NEED HELP)

ESK8 Mechanics
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#1

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 have the following information: from here

page 9 of gates design manual

So my questions are:

  1. What are the exact dimensions of the individual tooth.
  2. What is the position of the belt pitch line relative to the bottom of the tooth.

page 9 of gates design manual

BTW here’s a dummy belt for 56T belt on a 40T and 16T pulley.

blob.jpg1721×901 165 KB

2 Likes
#2

summoning @JuniorPotato93, @Pantologist, @zeinstra

#3

How can we be of service.

#4

I only started really learning CAD and stuff a few weeks ago lol. I am probably wrong.

  1. 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?

  2. 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…

#5

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.

#6

Tooth count is not the problem. I want to know how to draw a single tooth for HTD 5M belt.

#7

Oh okay. Does this help?

http://www.cshbelt.com/upload/htd-5m.gif

1 Like
#8

I’ve found myself with this same problem

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

Capturar.JPG1686×811 64.2 KB

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#9

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

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#10

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

#11

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

#12

@mishrasubhransu

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.

1 Like
#13

Just use this:

#14

@mishrasubhransu You can always download the profile from the vendor website in any 3D version you want like from http://shop.sdp-si.com/catalog/product/?id=A%206A25M040NF1510

Just click the download cad banner

IMG_0114.PNG1242×2208 325 KB

#15

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.

#16

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

#17

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.

Here’s that information for future reference.

Pasted image1711×362 27.4 KB
Pasted image962×736 66.2 KB

EDIT1: And this is what the pulleys look(40T, 36T, 16T)

HTD5_12mm_40T_wheel_pulley_snapin.JPG1595×841 399 KB
HTD5_12mm_36T_wheel_pulley_snapin.JPG1583×841 458 KB
pulley_motor_16T_HTD5_12mm.JPG1587×841 186 KB

7 Likes
#18

looks like you hit the nail on the head with that. Hope it prints out well!

#19

@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?

#20

@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