pic: Stripped VexPro gear

[cbale2000]

Originally Posted by frcguy

Sure. During auto the robot would go through the low bar, and then attempt to back over it. If our alignment was off, when backing up, the robot went in at a slight angle and was pushing against one of the side supports for the bar. The motors proceeded to run while the robot was pushing against the support for a good 5-7 seconds, causing the gears to grind. This happened once or twice until we dialed in our positioning. For context, this gear is part of the third stage on the 2 CIM ball shifter. It actually drives the output shaft.

That would certainly do the trick. Makes me glad we traction-limited the low-gear on our drive system.

That said though, of the 100+ VEX aluminum gears we've used on our competition robots over the past 3 years, the only time I've had issues with chipping teeth was on the choo-choo mechanism on our 2014 shooter (which, too be fair, was poorly designed, and over tensioned) so don't let them scare anyone away for most normal uses.

[BoilerMentor]

We broke one at our district championship event. The interesting and slightly concerning thing is that it wasn't at a particularly high load, just a sustained, consistent torque load due to a misaligned limit switch. The gear that failed is driven by a PG27 with a 16t steel gear on the output shaft and is only driven at partial power.

Unfortunately there isn't a steel option like these: http://www.vexrobotics.com/vexpro/mo...ore-gears.html

We only use a portion of the gear's circumference to actuate our intake, so rotating the gear is an option we'll likely pursue at champs if we have the down time.

[pilleya]

Originally Posted by BoilerMentor

The gear that failed is driven by a PG27 with a 16t steel gear on the output shaft and is only driven at partial power

Does the PG27 have a 9015 or a RS775-125, as there is a massive difference in torque and power output.

[BoilerMentor]

Originally Posted by pilleya

Does the PG27 have a 9015 or a RS775-125, as there is a massive difference in torque and power output.

RS775. It broke on the "down" actuation though, which is much lower applied power systematically. My guess is it's actually more related to shock load of the intake coming up against the hard stop that sets the height. It didn't affect our performance this time, so it isn't nearly as big of a deal.