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Unread 18-11-2013, 20:54
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thefro526 thefro526 is offline
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Re: Prototype transmission for potential use this year

Quote:
Originally Posted by magnets View Post
Neat idea. However, I am fairly certain that your worm wheel will loose teeth when you have the weight of the robot behind it. If your robot is going fast, and suddenly you stop applying power, the worm wheel won't be to turn the worm gear, so you'll just snap a tooth off. It will be different than just testing it on a table.

In the video you talked about having to use a smaller worm wheel in order to get the same reduction. These are pretty fragile, so you could switch to a bigger worm wheel with a two-start worm.
Depending on the exact specification of the worm wheel and worm this could be a very likely scenario. Like Magnets said, you could switch to a larger worm wheel and a two/four start worm to lessen the tooth loading, and it'll have the added benefit of being more likely to back drive. Under extreme loading rather than locking up.

Your wheel choice is also going to play a huge role in the overall setup robustness, something on the lower end of the scale should start slipping before the transmission fails, where a high traction wheel might not slip until after the gearbox fails, its hard to say exactly without doing some calculations.

Magnets also brought up the subject of shock loading the worm wheel and worm during deceleration which is a very, very likely scenario. A decent bit of braking code could help to lessen the chance of hard stops during most matches, but the right hit or two could ruin your day. If you really wanted to stick with the worm setup and have it lock, a clutch setup could do some really cool stuff, or even some sort of flex plate/flexible coupling in the system to ease the load on the gear.
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