Skipping gears issue

VEX V5 General Discussion General Forum
#1

Hello everyone.
We’ve come across an issue that I’ve never encountered before.
We have a 12T gear powering a 60T gear on our lift, and for some reason, they don’t mesh together properly.
Because of this, when the mechanism has too much resistance, it skips.
We tried doubling up the high strength gears, but that doesn’t help because they’re still too far apart
When we push up on the 12T gear, it’s movable a noticeable amount upward.

The only thing that I can think to do is to completely rebuild the lift with a 12T gear on both sides of the 60T gear, but that would mess up our scoring mechanism.

Does anyone know of anyone know of any other solutions to this problem?

#2

A picture would be helpful. It could be one of a few things

  1. Spacing between towers allows too much flex
  2. the thing attached to the 60 tooth gear is far too heavy causing ridiculous amounts of torque
  3. A worn out gear

There have been a few common fixes to these and we can point them out if we see what it looks like.

#3

Just a minute.
I’m having trouble with pictures on this computer.

#4

Here are the pictures.
20160825_110907.jpg
20160825_113905.jpg
20160825_110919.jpg

#5

Nothing real obvious…but probably flex in the shafts combined with slop in the bearing mounts. Move all the flat bearings to the inside (will shorten the shaft lengths reducing flex), use screws and nylocks instead of Keps nuts to ensure they stay tight. Use a High strength shaft for the large gear. Last resort-back up the 12-tooth gear with a free-spinning idler gear on the right-hand side shaft.

#6

The only thing I can think of is:

  1. The bearing is not aligned correctly.
  2. The shaft is bent.
#7

This looks like an arm lift, right? If so, what are you doing to take the load off the motor? Most teams use rubber bands to pre-load the arm so that the motor doesn’t do as much work.

Also, there is no advantage to using a 60-tooth gear on your arm. Use an 84, and take advantage of that 1:7 gear ratio (instead of 1:5).

#8

We aren’t using anything to assist our lift because it needs to reverse for us to hang.
We moved from a 1:7 to a 1:5 because it didn’t seem fast enough. 1:5 still has enough torque for everything we need.

#9

Use HS shaft on the 60 T.

#10

Thanks everyone! (Espetially @kmmohn)
It seems to be fixed now.

#11

Helpful advice

#12

That’s a great video!

#13

Sandwich your 60T gear with another 12T on top of it as an idle. This should keep the gears from flexing away from each other.

#14

While @yoneshige 's solution might mean you have to move your dumper down a hole or two, I think it’s probably one of the most effective ways to keep your gears turning. We experienced that with our v1 dumpapult design; we originally had 6 motors all at the bottom turning an 84 tooth gear at the top of the gear train, but experienced slight problems with twisting/bending; moving two motors to be above the 84 tooth gear and thus “support” it on both sides fixed the problem.

#15

To be honest, my team’s lift kept doing that too for some strange reason… However, I guess the gears need to be more “closer”, but I still haven’t figured it out.

#16