Gearbox breaking?

[ReggieB]

Has anyone else had problems with the gearbox plates breaking? We noticed that the gear and spacers were too big, and when we tighten the bolts it bends the plastic. We broke both of ours at the practice today. We replaced them w/spares and added aluminum plates to hold it together, but i wanted to know if anyone else has had this problem.

http://www.mbhs.edu/~aajohnso/robo04...20(Medium).JPG

[Sscamatt]

We had a problem with one of the plastic motor mounts breaking. This was just in assembling the robot together. Hope they last through competitions.

[rust710]

Originally Posted by ReggieB

Has anyone else had problems with the gearbox plates breaking? We noticed that the gear and spacers were too big, and when we tighten the bolts it bends the plastic. We broke both of ours at the practice today. We replaced them w/spares and added aluminum plates to hold it together, but i wanted to know if anyone else has had this problem.

http://www.mbhs.edu/~aajohnso/robo04...20(Medium).JPG

We had that problem last year. We went through about 6 sets of gearbox before the season was over. The gearboxes are not very strong and if the spacers are not exactly right, they will break.

[Team1425]

We broke one of the plates off somehow on our wooden version of our robot, since we have added a part of the supplied rectangular aluminum stock to both sides so that we can tighten it together better without bending the plastic.

Luckily another team gave us their gearbox assemblies since they wern't going to use them.

[ReggieB]

We also broke one of the "C" pieces of the drill mount, but that was probably due to over-tightening.

The aluminum plate looks like it will be strong enough, glad we arent the only ones with this problem.

[Gamer930]

We were having the same problem at Sussex last year. (We broke about 6 of them)

The way to fix this is to put a Plate on the GearBox with a small lip that goes under the gearbox. (We did the exact same last year and never had a problem since then)

If you look at this picture of this years drive. It already has it on :-)
http://www.chiefdelphi.com/forums/pi...gle&picid=6105

Link to disscussion about it last year: http://www.chiefdelphi.com/forums/sh...ad.php?t=18076

[Arefin Bari]

Originally Posted by rust710

We had that problem last year. We went through about 6 sets of gearbox before the season was over. The gearboxes are not very strong and if the spacers are not exactly right, they will break.

just want to point out that dont feel bad... last year we had to take our drive train apart 26 times during 3 competitions... our shifting tranny was underdesinged... but this year thats not happening again....

[Joshua May]

Last year we had that problem at competition, but that was because we were rammed in the side in the middle of a match.

[blindguyinanorg]

thats why this year we went with the aluminum bearing mounts

[ShadowKnight]

the gearboxes that FIRST provides, whiel adequate for some purposes, are plastic and as such, are prone to being broken quite easily. Those gearbox housing were designed for use with the helical gears provided in the kit, and helical gears, while not putting as much of a load on the gears themselves, exert huge forces on the actual gearbox housing. it is not wise to put those kinds of loads on a plastic gearbox housing.

[ReggieB]

I had known that some broke last year, but this year we were provided with "laser cut" spacers. Would have thought they'd help.