Shafts twisting

Hello, so so we have a lift and it “works” but one of the shafts keeps twisting badly. We are using V5 motors. I’m wondering anyone here could help me solve this problem. We have to 12 tooth gears powering a 60 tooth gear. The shaft on the 60 tooth gear twists and warps itself really badly. We only have seven motors 4 for our drive the last three are for our lift because one side of this 6-bar double reverse 2 bar lift is powered by two motors does that cause to much stress on this shaft? Will taking another motor from another group and attaching it to the other side fix this? what can I do?

I would suggest using a high strength axle on the 60 tooth gear.

I did literally the same thing last year. I could basically use my twisted (until snapped) shafts as screws.

I would suggest evening out the power on both sides. I’ve seen a lot of one motor DR4Bs, so a 3 motor 6 bad seems a bit overkill to me.

As you can see, the two sides are not going up parallel to one another. This puts unnecessary stress on the axels. Equalizing the power to each side will help a lot.

Also, it looks like you’re using lock bars on your arms. Due to the strain exerted over that small portion of shaft, I’m not surprised you’re getting twisting. I would bracevthat up with a low strength gear replacing a spacer or two. Looks to me like it would fit. Screw it to the rail in addition to the lock bar, and you should be better off.

Taking away the third motor for use elsewhere (probably active cap flipper or floor cap roller), you should still have enough power. If not, you probably have too much friction in the system. As previously mentioned, a lot of that friction could stem from the unequal power distribution. Check the joints for unnecessary friction and loosen them up if necessary.

High strength shafts, as mentioned above, are very useful, but because you haven’t tried that yet, I assume you probably don’t have any.

Additionally: an off topic thing I noticed is that you’re using a two-point rubber band connection system as opposed to a triangle system. For lifts, the triangle system is typically better. But I wouldn’t worry about that quite yet.

Okay, thank you!

Agreed, this has worked well for us. After we started to use HS Axles the lift also moved more consistently.

@Master_mind if you ever do a rebuild for your lift, try to make the larger gears directly connected to the lifting bars. I might post a picture of how we made it work in our lift. With how the motors power it and such.

If you have high strength axles use them, go all the ay across your system to make the gears on both sides connected, and your twisting will become negligible. If you dont have high strenth shafts, theyre 1/4 inch, and standard shafts are 1/8 inch, so if you bunch 4 standard shafts together, you have the same thing. Will have to do some drilling though. I have high strength shafts, so i dont have to mess with any of this, but you would have problems with getti g compatabel hardware, spacers, locking collars, etc. Usually friction is enough, but i couldnt be sure with this method.

The problem is that you are using the axle to transfer power to the lift arm. Power should be transferred by screwing the c-channel directly onto the gear using the mounting holes.

There is over 10nm of torque being transferred through that single axle, which is far too much for it to handle.

The fact you have 2 motors on one side and 1 on the other shouldn’t matter, but you should add a brace between the lower arms to help with power transfer. However what I will say is that 3 motors is excessive for powering a lift on V5.

High strength axles are not the answer, low strength shafts won’t bend if you use them correctly. However, if you were to change the pivot the 60t gear is on, I’d suggest changing it to a screw joint, as they have less slop. (But don’t cantilever!)

this is the solution, never use shafts to transfer power from a gear to a bar. screw your lift directly to your gears, and the strain is distributed throughout the gear, rather than the shaft