Timing Belt Design Guide 2

[bvanhiel]

I'm looking for a good design guide/resource on timing belts. I have one from Gates that seems pretty good, but didn't know if there was a better one out there. I'm paticularly interested in belt life explectations over small pulleys on 8mm pitch HTD belt.

-b

 

[satchmo]

My experience has been that the manufacturer's catalogs/resources are the best. I remember Gates being particularly useful, as you said. The Dodge engineering reference books are pretty good also. Your local supplier should be able to get you those. Also, call up the factory and try to speak to one of the engineers there (not a salesman). I've gotten some good information from those guys in the past.

 

[JJPellin]

We have recently gone through a lot of changes to our cog belt systems. The Gates documentation is probably the best I have seen. We started the effort because of a rash of failures of old HTD drives. In the end, we found we had an incompatibility between the old HTD sprockets and the new belts. All of the belt manufacturers will tell you that their belts are compatible with these old sprockets. They are wrong. I have found three distinct patterns of cog teeth and serious compatibility problems if they are mixed and matched. The keys to good reliability are these:

1. Matched sets of belts and sprockets.
2. Belts well tensioned and well aligned.
3. Belts properly designed for the loads.
4. Sprockets not below minimum size.

The old HTD belts were weak and tended to require very wide belts. All of the newer belts can carry much more load with a narrower belt. Excessively wide belts are difficult to align and can place excessive loads on the bearings. If the smaller sprocket is too small, it places too much side load on the motor bearings. This is the design aspect most often missed.

Most of our HTD drives are 14 mm pitch. I have very rarely worked with the 8 mm pitch. If you give some details about specific problems you have had, I may have applicable experience.


Johnny Pellin

 

[bvanhiel]

Thanks for the responses. There's usually one vendor that has the best design guide, and it looks like Gates is it. I'm new to designing with timing belts and wanted to make sure that I wasn't missing something better to get started with.

-b