Motorization question

[HenrikLego]

If anyone can help me out, will this work?

Motorization by Henrik Lorentzen, on Flickr

I am working on a large steam engine now and trying to find a way to motorize it. Do you think this will work, will add some more support to the technic cross axles, but the gearing? L-motor. I plan on putting another L-motor using the same technique on of the other wheels. But I want to check with some experts before I test this on a real build.

[Rail Co]

From my experience this SHOULD work. You will need some supports for the vertical cross axle. My only work of caustion is when doing gears like these is that if they aren't supported enough the like to warp or shift in ways that will disengage the two gears so just be mindeful of that.

I would wait for a more "expert" opinion before you make any final design descisions!

-RailCo

[Sven J]

Hi Henrik,

I'm sorry, but it won't work...
You put the driven axle through a 1x2 Technic brick with 2 holes, where the holes are placed directly underneath the studs. The vertical axle, however, has a bearing between two studs, so you'll have half a stud offset between vertical and horizontal axles. Try this part as a bearing for the vertical axle instead.

Apart from that, with the additional support you already mentioned, the principal drivetrain layout should work. The gear ratio should be fine; I found that the L-motors in my locomotives run with approx. 4 revolutions per second under load (at 7.4 V from the rechargeable battery box), which in 1:1 gearing leads to quite prototypical speeds.

Best wishes,
Sven

[deraven]

Just to clarify what Tenderlok is saying (if needed):  Your idea is fine, but the gears don't meet/engage each other down at the wheels.  You have to fix that alignment with a half-stud offset somewhere, either with the 3176 part as Tenderlok mentioned, or by offsetting the whole wheel assembly - whatever you want to do to make the gears mesh.

[HenrikLego]

Thanks for clarification and nice tips. I updated the model now:

Skjermbilde 2018-04-01 kl. 06.46.15 by Henrik Lorentzen, on Flickr

As seen in this image I plan on using another motor on the first driving wheels:

Skjermbilde 2018-04-01 kl. 06.57.12 by Henrik Lorentzen, on Flickr

Edited April 1, 2018 by HenrikLego

[zephyr1934]

Unless you need the extra 1/2 stud offset between wheels you can mount the axles 5 studs apart (or 5 technic holes). The blind driver will run just fine in front of the flange of the flanged driver. Doing so removes the half stud offset problem mentioned above. As your frame is currently, the 1x2 technic brick with two holes will be a weak point, the frame would be much stronger with a long technic 1x brick holding all of the drivers. If you do need the half stud offset, for greater strength I would suggest using the longer technic brick for the axles that are powered.

Another point with the current design, you are driving the blind driver. The blind drivers float above the track so you this design would have to transmit the power to the flanged drivers by way of the driving rods. As long as you use a strong enough rod it should work, but you will probably lose some energy that route. If you can re-engineer it to power the flanged driver I think it would run better.

[Beck]

Short answer no-

The red gear in my picture will be forced downward. The mockup to the left is better. Alternatively you could just use a technic part to hold the gears together as show to in the picture.

PS.

Do NOT use knob gears for trains- they are terrible

 

 

 

Edited April 1, 2018 by Beck

[HenrikLego]

Thanks for all your input. I will go back to the drawing board and see what I manage to improve.

zephyr1934: I need the offset to match the driving rods I bought from your Bricklink-store. Great parts btw :)

[Duq]

As Beck said, 'bracing' is needed for reliable running; using a construction that prevents the gears from skipping.

The parts he shows on the left are very good for that. The round tile with a hole is also a good idea for two reasons: it keeps the horizontal gear at the right height and it has less friction than running it on the studs of a Technic plate.

This construction works well for me:

PF L-motor mount by Duq, on Flickr

Looking at the larger picture of your engine I would recommend linking the two motors. Turn the front one around and let them both drive a single axle down to the wheels. That will give you a number of advantages: you're driving a flanged wheelset. Your flanged axles sit in normal Technic bricks so no messing with half-stud offsets. But most importantly: motors never turn at the exact same speed. The way you have them means that the front and rear driven axles will slowly try to get out of sync, putting a lot of stress on your connecting rods.

And yes: avoid knob wheels at all cost: they're the most inefficient gears you can use.

[zephyr1934]

18 hours ago, Duq said:

Looking at the larger picture of your engine I would recommend linking the two motors. Turn the front one around and let them both drive a single axle down to the wheels. That will give you a number of advantages: you're driving a flanged wheelset. Your flanged axles sit in normal Technic bricks so no messing with half-stud offsets. But most importantly: motors never turn at the exact same speed. The way you have them means that the front and rear driven axles will slowly try to get out of sync, putting a lot of stress on your connecting rods.

Adding to this, I would recommend that you only put traction bands on the driven axle. If you have traction bands on non-driven axles you will get more resistance in curves.

[sed6]

1 hour ago, zephyr1934 said:

Adding to this, I would recommend that you only put traction bands on the driven axle. If you have traction bands on non-driven axles you will get more resistance in curves.

I second that and suggest you put them only on one side. This will allow the side without bands to slide easier going around curves. If you band both sides you'll notice a reduction in speed going around corners accompanied by a squeal as one side tries to slide, this is due to the difference in distance the inside wheel must travel vs the outside wheel. 

[HenrikLego]

Thank you so much guys for all these wonderful tips!

@Duq I actually saw that gearing example on flickr by @Selander yesterday and planned on looking closer on it to see If I could use it.

Will post updates when I have tested more. Your help is greatly appreciated!

[HenrikLego]

Here is an update, so @Duq this was your idea? It seems really tight and nice, and it seems I can fit it in!

 

Here is an overall sketch of the train set, gathering parts for the carriages right now.

[Sven J]

That train is great!!!!!! Can't wait to see it in real bricks! The wooden carriages are so cute, and the NSB class 49 is an absolutely stunning prototype (when one of the Krupp-built engines was tested by German Reichsbahn engineers before delivery to the NSB, they were utterly amazed about its performance).

It looks as if you've eliminated the half-stud offset problem. If that shouldn't be the case, this part can also be useful as a bearing for a Technic axle. With LEGO print on it, it's also part of keychains and sometimes used by Bricklink sellers as a free giveaway...

Edited April 6, 2018 by Tenderlok
NSB, of course, not NS.

[zephyr1934]

Those cars look good in the distance shot, the clearstory roofs are well executed.

[HenrikLego]

I starting building a prototype of the motorization yesterday when the motor's arrived. I will test it on track tonight!

I have built two of the four carriages as well so can test how it works pulling those.

I tried putting rubber bands identical to the ones from Emerald Night on the BigBen Brick wheel, but they keep popping off. Any idea on how to fix?

Edited April 19, 2018 by HenrikLego

[Selander]

Try to cut circular segments of bicycle inner tube, and put those on each wheel.

I've used it successfully on BBB medium wheels.

You need a groove in the wheel to use o-rings like those EN wheels have. Otherwise they will slide off. 

Edited April 19, 2018 by Selander

[LEGO Train 12 Volts]

You can read this old but useful topic BBB wheels with grove  by toastie 

Your project looks promising ...the wagons are a masterpiece!

[HenrikLego]

It's been a while, but the train is coming together

[sed6]

Nice to see you're making progress! I think your front wheels need some attention. It's hard to tell from the pic but it looks like they have only a single pivot point? Back by the main wheels? You're going to need dual pivot points for the front wheels to stay aligned with and follow the tracks. With only a single pivot point the fronts will bind and jump the track. Below is a shot of the Emerald Night instructions which shows an example of how to make dual pivot points. There are many different ways to accomplish this though. Keep up the good work!

 

[supertruper1988]

1 hour ago, sed6 said:

Nice to see you're making progress! I think your front wheels need some attention. It's hard to tell from the pic but it looks like they have only a single pivot point? Back by the main wheels? You're going to need dual pivot points for the front wheels to stay aligned with and follow the tracks. With only a single pivot point the fronts will bind and jump the track. Below is a shot of the Emerald Night instructions which shows an example of how to make dual pivot points. There are many different ways to accomplish this though. Keep up the good work!

 

It looks like he has a 2-8-4 wheel config, which is sone with a single rotation point. 

[sed6]

36 minutes ago, supertruper1988 said:

It looks like he has a 2-8-4 wheel config, which is sone with a single rotation point. 

Ah, didn't know that. Thx. 

[HenrikLego]

I got some nice help regarding my train earlier and I need some help again. Does anyone have a solution to this?

The mechanism pictured here works, but it causes a lot of friction. Each technic Axle is going through three 1x1 technic Brick with holes. Are there any other ways to solve this that includes less friction?

Edited December 19, 2019 by HenrikLego

[Daedalus304]

5 hours ago, HenrikLego said:

I got some nice help regarding my train earlier and I need some help again. Does anyone have a solution to this?

The mechanism pictured here works, but it causes a lot of friction. Each technic Axle is going through three 1x1 technic Brick with holes. Are there any other ways to solve this that includes less friction?

 

The biggest issue I see is that it doesn't appear your piston is secured very well. You want the piston to stay rigid and the holes for the technic axles need to be lined up nice and straight - that should work smoothly once you get it aligned well.

Once you've done that, you can also go down to only 1 technic brick with a hole per rod. You can use a  1x2 Wall Panel to cover up the gap.

Hope this helps!

[zephyr1934]

10 hours ago, HenrikLego said:

The mechanism pictured here works, but it causes a lot of friction. Each technic Axle is going through three 1x1 technic Brick with holes. Are there any other ways to solve this that includes less friction?

The pair of axles going into holes is probably a killer. I try to avoid using technic axle into technic hole. For the valve gear I like to terminate it at a black technic beam, e.g., in the following example... though the pin is not actually in the beam in the render and I prefer using a 2 long beam rather than a 3 long)

 

Then for the main cylinder I prefer to use a pair of bars with a technic half pin, a LOT less friction than a technic axle

 

Both work very well in my experience.