DNR Shifter Issue

[StudWorks]

I had a lot of problems with my MOC work-in-progress and I am hoping this will be the last of them. I am using the Porsche 911 GT3RS’ DNR shifter but the 12t gears here aren’t strong enough, making them skip and bend their teeth.

I would appreciate if someone could show me a sturdier way or an example of a drive + reverse gearbox design, as compact as possible, with no gear skipping.
Thank you. 

[emielroumen]

Hi Studworks, are you describing the same issue in this thread?  It would make sense to keep it all in 1 instead of 2 threads.

[Didumos69]

I know it can be frustrating to not get something to work, but I'm afraid I can only really help if I could study the entire model. Apparently there is some serious friction going on which causes all kinds of issues, for example the slipping gears you are showing. Do you have a 3D file of your model?

Btw, I agree with @emielroumen that it would be better to keep this all in one thread.

Edited December 2, 2019 by Didumos69

[Mechbuilds]

Like people have said in all 3 of your threads about this same issue.. The design is flawed and needs to be completely redone. 
Take those 12t gears and throw them in the trash so you'll never put them on this same moc again 

You have room to expand the gearbox by one stud to make a different build. People also gave you 3d models on alternate gearboxes that fit. 

[Appie]

3 hours ago, emielroumen said:

Hi Studworks, are you describing the same issue in this thread?  It would make sense to keep it all in 1 instead of 2 threads.

This is actually already the third topic on the same issue. . 

[StudWorks]

Thank you everyone for your feedback. I am sorry, my intention was not to make another post on the same topic. I mistakenly made this as a new post because I wanted to put the emphasis on having a stronger gearset with the DNR shifter. The EV3 motors that power the car are very strong and I need to eliminate all of the gear skipping.

I only have the space under the driving ring to put stronger gears.

This was the original weak set of gears I had that kept on skipping. I thought about replacing the setup with knob gears but they couldn’t fit under the ring. Of course I would do that if I could fit it. I would like to find a design example compact enough and as strong as the knob gears with no skipping.

@Didumos69 It is the motors that are causing the skipping because the 12t gears are too weak. Any ideas for a stronger redesign for this section as seen in the pictures above? I don’t believe the MOC is a flawed design, just this section is because of the 12t gears. Thanks. 

[LegoTT]

You can use the new epicycloidal hub if you dont mind the gear ratio

[suffocation]

No matter how you spin it, high torque and bevel gears (let alone half-bevel gears) don't get along very well.

You need to redesign the chassis to accomodate a solution using spur gears - something like this, which @aeh5040 posted in your previous thread:

 

Edited December 2, 2019 by suffocation

[LegoTT]

I meant if he put the new hub instead of the fork, he would have the reverse gearing

 

[agrof]

15 hours ago, StudWorks said:

I had a lot of problems with my MOC work-in-progress and I am hoping this will be the last of them. I am using the Porsche 911 GT3RS’ DNR shifter but the 12t gears here aren’t strong enough, making them skip and bend their teeth.

The tan gears are quite strong, if they not break, than there is still some bracketing issue which causes the slip, I guess. Without seeing a lot details, I see, that the bracket is not fixed solid enough.

I would recommend to try this solution below, if this still doesn't solve the issue, you must rebuild completely. Also make sure, that the 5.5 L axles can not slide outwards - the shoulders of them should help here. LDD model is HERE.

Edited December 2, 2019 by agrof

[tomek9210]

Maybe use driving ring extenders for the shifter and then use the other holes of the bracket as well. It might help.

[Mechbuilds]

18 minutes ago, tomek9210 said:

Maybe use driving ring extenders for the shifter and then use the other holes of the bracket as well. It might help.

This guy will just make a 4th thread about it and ignore all the help we gave him.

[Gray Gear]

4 hours ago, Mechbuilds said:

This guy will just make a 4th thread about it and ignore all the help we gave him.

Agreed

[sirslayer]

Would this work???   it seems to handle some torque as I twist it..  but It is hard to slide the second axle in but I manage to do so ,  It uses an Axle 3 with Stud 

lego technic by victormendoza_jr, on Flickr

 

[Mechbuilds]

@sirslayer's parts sure look like they've been used hard. Rock n roll! 

[StudWorks]

I appreciate the helpful posts and I tried many options suggested. This illustration below (as per multiple recommendations) is my favorite. Far better than what I originally had. I yanked out the old one and put the new one in according to LDD design illustration provided by @aeh5040 and I’m finding ways to put it in the drivetrain and reinforce it properly.

The red pin is input and the yellow pin is output

When fitting it into the chassis, I would like to have the entire setup be 5 studs wide to fit in my MOC, as shown with the blue beams above.

This is my first time building a custom gearbox and it seems quite challenging to do so, any tips on how I should "case" the gearbox (reinforce it with tough pieces) and place it into my build? Thank you.

[Mechbuilds]

You could swap one of the 3 long beams into a 5 long beam and attach it to the chassis. 

[StudWorks]

@Mechbuilds Thanks, that helped with mounting in the gearbox, along with a 4L L-shape beam.

Progress is going well, but there is plenty left to do.

Mounting the gearbox to the floor is my next challenge, the piece where I am pointing at seems difficult to mount to the plate properly. Any ideas?

[grego18f]

Hi @StudWorks,

From what I can see, the front part of your chassis is very similar compared to @Jeroen Ottens's DB11. If so, I can propose you the Mod done on the DNR console.

https://bricksafe.com/pages/grego18f/mack-granite/aston-martin-db11---mods

Feel free to use it if you find it useful! 

[StudWorks]

Hi @grego18f,

Yes the chassis is based on the DB11, but I modified most of it. Thank you for your input, it does help me. 

[StudWorks]

Update on my MOC:

So I put together a drivetrain using the new DNR gearbox design recommended to me and did some tests to see how much torque it could handle until gears start to skip.

This DNR gearbox design is far better than the previous one I was using. However, during my initial testing the torque has somehow managed to be strong enough to make the gray gear selector rings skip inside the red gears.

I removed one of two 90 degree limiters to make gear shifting (via paddles) more easier, so putting it back on would hopefully solve the issue (the torque is so high it almost shifts into another speed).

Here's a red gear that got its inner teeth damaged from the gray rings skipping them. Any thoughts on if the removal of the limiter as mentioned above is causing the skipping or is it something else?

The new DNR gearbox is also having some reinforcement issues. Here's a picture of it staying still...

And under high torque, where things start to bend slightly. Any advice on how I could reinforce this better? Thank you.

[suffocation]

Before addressing the obvious chassis reinforcement issues, ask yourself how much torque you really need.

[tomek9210]

The beams holding the shifter should be part of the chassis, now they are not. The mounting points are too far away from each other.

[Zerobricks]

From my experiences the orange wave selectors are not really suitable for high torque gearboxes.

[Gray Gear]

Why do people use panels for framework? Imo they are inferior to frames. Like in this case, you have a 7 studs wide center tunnel, so why lose out on the best mounting option, and use panels insted? I dont get it.