Steering mechanism for tight wheel wells?

[DLuders]

@ Superkalle: What happens when you remove the two Technic Half Bushes from the front of the car, and replace the four blue (friction-type) Axle Pins with the (non-friction-type) 3749 Axle Pins? Everything would be more free to slide around, and the wheels could possibly turn at a greater angle.

Edited June 22, 2011 by DLuders

[le60head]

Hey guys!

I am following this topic with great interest! I am currently unable to try out this steering setup myself. I am curious to get my hands on it though!

Thanks superkale!

I'm looking forward to receiving a replacement motor for the steering. When it's done and works 100% well, i'll show it gladly :) The main problem i am facing is that the self-centering steering isn't working very reliable. When i'm satisfied with the prototype, i'll try and make detailed building instructions.

Good luck with your project!

[Nazgarot]

@ Superkalle: What happens when you remove the two Technic Half Bushes from the front of the car, and replace the four blue (friction-type) Axle Pins with the (non-friction-type) 3749 Axle Pins? Everything would be more free to slide around, and the wheels could possibly turn at a greater angle.

The problem with this setup is it can't be steered... I might be modified to be steered, but I can't see how...

[AussieJimbo]

With a bit of playing around I'm 90% done with a solution that turns the wheels in a nice tight space. It's a bit tall but not quite beyond concealing in a City truck or bus. I just need to link the push-pull mechanism to a steering wheel, any suggestions on the easiest way to do this or to improve the overall design would be appreciated.

Steering left

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Steering right

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:classic:

Edited June 23, 2011 by AussieJimbo

[AussieJimbo]

A bit more tinkering and I've managed to get a really rough proof of concept built.

Plenty of room for refinement but the mechanism works. I used a double rack and pinion arrangement to drive the steering mechanism.

Would be nice if I could get a bit more lock out of the steering but I'm pretty pleased with what I've achieved so far.

(Sorry, the pics are a bit rough too.)

Little dark grey pinion gear between two racks, steering left (ignore image name).

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Steering right (ignore image name).

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Slide for end of lower steering arm to ensure rack stays engaged with pinion. Upper arm has tile sliders on it for the same reason (not shown).

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The proof of concept is a bit long because I've had to scrape together odd technic beams, I'm sure it could be significantly shortened.

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:classic:

Edited June 23, 2011 by AussieJimbo

[Mephistofeles]

The problem with this setup is it can't be steered... I might be modified to be steered, but I can't see how...

Might be done this way?

Edited June 23, 2011 by Mephistofeles

[Superkalle]

Might be done this way?

Interesting.

Can you attach the LXF please?

(just change the suffix from LXF to ZIP and it will work)

To everyone particpating in this joint mechanics challenge.

Just to make sure - we are all agreed that the problem is to create a "virtual" turning point that is on the rim center line (see lower images below). This because the turning point with a LEGO-wheel (at least the smaller ones) is far outside the rims center line, so the wheel travels very much forward and backward as it steers. To make a solution with LEGO wheels, the wheel have to rotate around the steer poing AND at the same time the entire steering mechanism have to move foward/backward, thus giving the effect that the wheel turns completely tight inside the wheel well.

And please note, it has to turn completely inside a tight wheel wheel. For example these wheels have to turn inside a wheel well that's 4 studs long. It's an extremly tight fit. 5 studs long could be accepted as well, but more then that and the vehicle will not look realistic.

Having said that, I'm still not close to a solution yet. I see in front of me how it has to work - problem is to convert into a clever LEGO solution

[Mephistofeles]

Here it is.

Steering.zip

[Superkalle]

Here it is.

Thanks

I had a look at it, and unfortunately it will not work (same mechanism/principle as discussed earlier). (PS: YOu did know that you can test/rotate these kind of mechanisms in LDD, right?)

But thanks for uploading.

..and welcome to the forum BTW

[Alasdair Ryan]

I have made a couple of combinations i hope one might work for you.

Edited June 24, 2011 by Alasdair Ryan
Removed over-sized pics

[Superkalle]

I have made a couple of combinations i hope one might work for you.

Hi there

I'm not sure what to make of this since these are standard steering mechanism. I understand you mean well, but It'd be much appreciated if you read the topic first. For example just a few posts above is a clear definitition of the problem at hand. Also, the pics are above the size limit, so I'm forced to remove them. Sorry.

[AussieJimbo]

Well my proof of concept is now an 8 wide bus.

Just preparing a post in the Town forum.

:classic:

Edited June 24, 2011 by AussieJimbo

[Alasdair Ryan]

Well Thats alright but i must say that i have used that size for over 2 years now and this is the first time there to big (nobody as told me untill now).

I read your reply in this page (above) about how exactly you wanted them to be set up.

Above you said you wanted the axle to be in line with the pivot point The first and last one is disgned just for this.

Happy building

Edited June 24, 2011 by Alasdair Ryan

[Mephistofeles]

Well Thats alright but i must say that i have used that size for over 2 years now and this is the first time there to big (nobody as told me untill now).

I read your reply in this page (above) about how exactly you wanted them to be set up.

Above you said you wanted the axle to be in line with the pivot point The first and last one is disgned just for this.

Happy building

No. We want to create mechanism which will have virtual pivot point in the center of the wheel, like in real cars.

[Superkalle]

Well Thats alright but i must say that i have used that size for over 2 years now and this is the first time there to big (nobody as told me untill now).

I read your reply in this page (above) about how exactly you wanted them to be set up.

Above you said you wanted the axle to be in line with the pivot point The first and last one is disgned just for this.

Happy building

If you could please repost the pics (but try to make them smaller, and also zoom in, there was a lot of grey on the sides), that'd be much appreciated.

EDIT: Ah, I see you did - well, no need to excagerate by making them that small. You're attitude (including the "Happy Building " is not appreciated. Please tread easy from now on.

Well my proof of concept is now an 8 wide bus.

Just preparing a post in the Town forum.

:classic:

Looking forward to that

[Superkalle]

Yes, i wonder the sme. I was disapointed when the new technic 8110 U400 unimog was precented. Here they have made new hub parts, but the rotation point is 5! studs away from the hub... I want a part that puts the rotation point inside the rim, and wheels with enough offsett that the rotation point is in the center of the wheel.

I'm usually not a fan of modifying lego parts, but now I grow tired of waiting for these kinds of parts, so I might make some by myself...

Just had a look at a video of the Unimog. The turning radius is even worse than what I thought after reading your comment. It's actually so bad, it's hard to belive.

[JunkstyleGio]

it's hard to believe.

...

Remember the 8070 has a turning radius that is the same...

(And so has the 8297, 8258 and all the big models.....)

It seems inherent to the size of the model!

[Superkalle]

Remember the 8070 has a turning radius that is the same...

(And so has the 8297, 8258 and all the big models.....)

It seems inherent to the size of the model!

I don't have any of those models, but it they are the same it strange, because with bigger vehicles you get the feeling it should be possible to build a better, more tighter turning steering geometry.

[Nazgarot]

Remember the 8070 has a turning radius that is the same...

(And so has the 8297, 8258 and all the big models.....)

It seems inherent to the size of the model!

None of these have a steering even remotely similar. The wheel hubs of this cars have a rotation point from zero to two studs from the rim. This gives them a lot better handling then a vehicle with 5 studs between the rotation point and the rim. Ideally the rotation point would be inside the rim, but this would require a different wheel, with negative offset.

As for the turning radius, its larger on the 8110. On the sets mentioned it can even be modified to be tighter. The reason for this is that the 8110 needs a lot of space in the wheel wells because of the 5 stud distant rotation point. This limits the angle the wheel can have, and in addition a large angle on this kind of construction gives bad stability.

What we here are trying, is to avoid these problems by transferring the rotation point to the center of the wheel. This should have been possible for TLG to do when they made new parts, but the result is far from pleasing (in my opinion). Lego lacks a good part to give realistic steering to both large and small vehicles. But at the same time, this is what makes Lego such an interesting challenge; How to make something that doesn't exist, with art we have... For smaller models it is possible, as proven in the buss a bit up in the thread. But for larger driven vehicles it's a recurring problem. The parts used for steering in 8070 and 8297 are good for making a realistic steering in non driven models, but lack the strength for use in a driven model.

A lot of us are trying to find a way around this problem, and for smaller vehicles this tread is a great start. I'll try to convert some of these ideas to larger scale, but it's a problem to make it sturdy enough...

-ED-

[Superkalle]

A lot of us are trying to find a way around this problem, and for smaller vehicles this tread is a great start. I'll try to convert some of these ideas to larger scale, but it's a problem to make it sturdy enough...

-ED-

Thanks for a summary of the situation.

Whenever you have something to share, please do, even if it is for larger vehicles.

[AussieJimbo]

Edit: This one looked nice but was too flimsy, see below.

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I've built a new wheel subassembly that gives a point of rotation above rim centre and should allow me to shave at least 2 studs off the width of the overall steering mechanism.

The wheel will rotate about the top blue half-pin. You can slide the beige brick a little to shift the point of rotation with respect to the rim. You can also replace place the grey 3/4 pin with a blue half-pin for use with a smaller wheel.

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With any luck, a 6-wide vehicle with tight steering is not far off.

:classic:

Edited June 26, 2011 by AussieJimbo

[AussieJimbo]

Edit: Didn't work, see below.

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Looks like it might work but the I think key question will be the torsional strength in the connections with the black cylinder.

Won't know until tomorrow, too late to embark upon the steering linkage tonight (and I want to pay attention to Q3) :-)

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:classic:

Edited June 26, 2011 by AussieJimbo

[Superkalle]

Looks like it might work but the I think key question will be the torsional strength in the connections with the black cylinder.

I'm not sure I fully understand your solution (or I haven't understood it). The way it's designed, you can't incorporate it in an car or truck design since the space above the wheel is occupied by the upside down 1x1 technic brick. Also I'm not sure I undestand how the steering shall be controled (i.e. the wheels turned). The solution also uses several illegal connections, such as the pin inside the 1x1 round brick. As you mentioned yourself, it also looks very unstable. Well, well - let's see what it involves into

[AussieJimbo]

No such thing as an "illegal" connection in my book. (well maybe some, but I don't think that one breaks any rules) ;-)

However it really was too flimsy so it was back to the drawing board. Sometimes you have to get it wrong a few times to work out what you need to do.

I've now got a much more stable technic built wheel assembly which I'm confident I can build into a steering mechanism tomorrow.

:classic:

Edited June 25, 2011 by AussieJimbo

[AussieJimbo]

OK, here's the latest version.

I'll probably attach push rods to those lugs (T-pieces which I forgot to replace with red technic 2 axles).

That will definitely be a job for tomorrow, it's 3:30am here. Can't help myself when I'm working on an idea. :doh:

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:classic:

Edited June 25, 2011 by AussieJimbo