Impact Loads into motors

[Centaur]

Does anyone here have any experience with impact loads transferring directly into a gearbox/motor?

I'm in the process of designing my first robot, and I noticed that almost every robot out there has the wheels attached directly to the output shaft of the motor/gearbox, and many of the wheels are unprotected.  So what happens if your robot runs full speed into something like a table leg with the wheel taking the brunt of the impact?  Doesn't this damage the gearbox?

If you use soft pneumatic rubber wheels, or air filled tires they would cushion some of the blow... 
I think I'm going to put a protective bumper around my wheels, but I was just wondering what everyone else does.  I'm also curious if anyone has ever ruined a motor/gearbox from this.

[frank26080115]

robot's are not usually very heavy or are very fast, so the impact doesn't damage the shaft or bearings inside the motor. it's usually not a problem.

[Kohanbash]

robot's are not usually very heavy or are very fast

Hi
You should checkout the DARPA grand challenge vehicles for size (teramax) and speed (most of them).
Also check out crusher (really heavy, really large)

[Admin]

This is the #1 way to break the gears on a servo.

Actually, there are simple equations to determine what force is needed to break the teeth on a gear. Its mechE 101 really, just google around for it. You will need to know the exact dimensions/material of those gears, too.

In reality, a good motor datasheet should specifically say how much force the motor can handle. And those gears should be able to properly handle it.

Adding shocks for the proper collision frequency could help a bit, too.