Pendular suspention without mini turntables

[SNIPE]

Heres a big complex lego technic problem, how can I link up some 5x7 frames with steering racks on top with some sort of pendular lego element?.

A mini turntable for pendular suspention is getting in the way of the steering axle, and the steering axle cannot go any higher.

Basically a mini turntable is too tall for a 7L gear rack & 12 tooth gear with axle.

 

Edited February 10, 2020 by SNIPE

[sirslayer]

Tough order you requested, I've done all pendular suspension Corvette 4x4 and I really liked the outcome.I needed to add shocks to the rear axle to prevent the body to roll and I had to switch the steering from a geared based to a linked style that is similar to the Lego 8860 40th year anniversary model!!  Some folks might say on my setup there would be to much friction.  My video link shows they are incorrect!!  The diagram is just a quick version of my setup and the turntable is just for reference

 

  UntitledModel_2 by victormendoza_jr, on Flickr

 

Edited February 10, 2020 by sirslayer

[suffocation]

Is it drive & steer or just steer?

[Ivan_M]

If it is samll model and space is an issue then I would go with axle only, if it is bigger then you can use big turntable

[SNIPE]

7 minutes ago, suffocation said:

Is it drive & steer or just steer?

drive & steer with custom shocks.

15 minutes ago, sirslayer said:

Thanks, unfortunatley this would be too weak since the frames are only held together using an axle so can be pulled apart.

[sirslayer]

Its only one axle!!!  the rest are pins ad connectors with beams and anyway I've never had that issue but if I was towing a ton of bricks then I can see your point.. good luck!! 

[SNIPE]

10 minutes ago, sirslayer said:

Its only one axle!!!  the rest are pins ad connectors with beams and anyway I've never had that issue but if I was towing a ton of bricks then I can see your point.. good luck!! 

I can try it, but my model has 8 wheels so 4 diffs and 4 frames. It therefore had 5 mini turntables

[sirslayer]

I almost forgot about this setup !! its based from the Lego set 8261 and I replaced the steering with a drive shaft 

IMG_20180915_001910 by Victor Mendoza Jr, on Flickr

IMG_20180915_002533 by Victor Mendoza Jr, on Flickr

8261-3-500x500 by Victor Mendoza Jr, on Flickr

 

Edited February 10, 2020 by sirslayer

[pleegwat]

Wouldn't the steering axle obstruct the pendular suspension anyway? Have you considered using lever-based steering instead?

[Jurss]

How You plan to get steering working with that kind of setup, if both axles will swing differently?

[sirslayer]

a linked style that is similar to the Lego 8860 40th year anniversary model should work. 

 

Edited February 11, 2020 by sirslayer

[SNIPE]

5 hours ago, Jurss said:

How You plan to get steering working with that kind of setup, if both axles will swing differently?

Ah thats the cool bit, because the pivot IS where the steering axle is but is not meshed to it, the steering axle can stay stationary.

Heres where it gets kinda hard to explain but I like gear racks but have considered linkage based steering, it will probably end up taking up even more space unfortunatley. Space here (in this MOC) is literally measured by the milemeter not by 1 or 2L because its so compact.

I'm considering this solution anyhow:

It is connected just by the top of the springs and the ball joints+links. and the driveshafts.

But still am kinda bummed that I can't have the best of everything in one assembly (mini turntabels, gear racks, springs, differential, steering on all axles.

It will still have steering, drive, and suspention at least.

 

[sirslayer]

@SNIPE You didn't say you wanted a live axle .. well feast your eyes on this ..  this module can be chain together for a 8x8x8 or 12x12x12 chassis configuration and each module features 4x4x4 ackermann steering with king pin inclination, live axle spring suspension riding on 49.5mm tires. you can move the spring setup over the tires if you need room or you can remove the springs and wishbone setup and it becomes a low profile pendular suspension.. if requested , ill setup a download link at Bricklink and yes, its an all original design by me!!

4x4x4real_3 by victormendoza_jr, on Flickr

 

lego technic 4x4x4 steering suspension by victormendoza_jr, on Flickr

lego technic 4x4x4 steering suspension by victormendoza_jr, on Flickr

Edited February 12, 2020 by sirslayer

[dhc6twinotter]

16 hours ago, SNIPE said:

Ah thats the cool bit, because the pivot IS where the steering axle is but is not meshed to it, the steering axle can stay stationary.

Heres where it gets kinda hard to explain but I like gear racks but have considered linkage based steering, it will probably end up taking up even more space unfortunatley. Space here (in this MOC) is literally measured by the milemeter not by 1 or 2L because its so compact.

I'm considering this solution anyhow:

 

It is connected just by the top of the springs and the ball joints+links. and the driveshafts.

But still am kinda bummed that I can't have the best of everything in one assembly (mini turntabels, gear racks, springs, differential, steering on all axles.

It will still have steering, drive, and suspention at least.

 

 

Nice effort there, but I think there are some things to consider:

1) Your driveshaft linking the two axles together like this will force your axles to work in a more pendular manner in relation to each other.  Is this your goal?  Your original idea of using the mini turntable may work if you are willing to offset the steering shaft to one side or the other (see below, however).

2) Your steering shaft running from one axle to the other will not work in this configuration.  When your axles pivot around the driveshaft, your steering shaft if going to move in every direction.  If you are going to use a steering shaft rather than linkages like victormendoza mentioned, you are going to have to use a u-joint and cv-joint with probably at least a 6 or 8L axle between the two.  

3) Your steering configuration will cause the axles to steer in opposite directions.  Is that your goal?

4) Your knuckles need more bracing, and I don't see a pivot point.  The knuckles should have a pivot point in line with the CVs. 

5) Your springs are mounted in such a way that doesn't provide much articulation.  You'd be better off rotating the mount 90 degrees, but even that isn't optimal.

6) I would suggest removing the 6L links.  This configuration will cause binding on the driveshaft, unless you use u-joints and cv joints on the driveshaft as well. 

 

4 hours ago, sirslayer said:

@SNIPE You didn't say you wanted a live axle .. well feast your eyes on this ..  this module can be chain together for a 8x8x8 or 12x12x12 chassis configuration and each module features 4x4x4 ackermann steering with king pin inclination, live axle spring suspension riding on 49.5mm tires. you can move the spring setup over the tires if you need room or you can remove the springs and wishbone setup and it becomes a low profile pendular suspension.. if requested , ill setup a download link at Bricklink and yes, its an all original design by me!!

lego technic 4x4x4 steering suspension by victormendoza_jr, on Flickr

 

Great render, and I wish I had those rendering skills.  Have you built a real version of this suspension?  Some thoughts to ponder:

1) How many connection points does each axle have to the suspension arms?  It looks like each axle only has two connections, and this won't work.  Maybe there is a mount somewhere else that I'm not seeing?  Are the two axles physically connected to each other in any way, other than a driveshaft?

2) The driveshaft is going to have a lot of friction, and probably bind up if you are using it to keep the axles in line with each other.  The center driveshaft will probably slide out of the pinion gears when the suspension compresses, if you don't have anything else keeping the two axles together.

3) Those red connectors are going to be pushed out when the suspension compresses.  

4) The steering linkages are a good idea, but the configuration of the pivot points is going to cause the axles to steer in opposite directions. 

 

Digital renders can be a great tool, but I think physical builds are almost always needed to understand the geometry and forces at play, especially for suspension designs. :D

 

 

 

 

 

Edited February 12, 2020 by dhc6twinotter

[Jurss]

16 hours ago, SNIPE said:

Ah thats the cool bit, because the pivot IS where the steering axle is

I will be shorter as @dhc6twinotter - And what about that drive shaft then? Or those both axles will swing together, there is no possibility, that they will swing in opposite directions?

[sirslayer]

@dhc6twinotter thank you for your feedback, no, I haven't built it yet in real life, but I've done a similar  setup without the suspension on a modified 42068 (that's where I got the steering idea from :) (suspension is based from my last real build Black Widow 8081 mod)

1.The center drive shaft on this render was original meant for the pendular suspension setup and it evolved into this design and it lacks the center mount and an I beam under the frame to connect the two 5x7..( i didn't know what was snipe mounting requirement to body so I left it empty) next update

2. The render doesn't show the front and rear mount , connects with u-joint between modules (unknown requirements from snipe, I assume its for the lego set 42108)   easy fix once the mode of transportation is establish, next update

3. Good point, can be fixed from real build (I need to build it in real life and easy fix) next update

4.It's a good idea and you're correct, 2nd platform is on backward (easy fix on next update) 

 

Update: I can easily slip a small turntable is between the 5x7!!! and flip the steering level to the opposite side to keep the current steering link   ill figure it out :) 

Edited February 12, 2020 by sirslayer

[SNIPE]

17 hours ago, sirslayer said:

This looks good, I will try to imcorporate it into my design but shorten the height of it too, trouble is I cant have a wheel spacing more than 15L all while having steering, suspention and drive with a differential.

My idea of having the pivot point where the steering axle is may not work on second thoughts and there is a pivot point but I cant figure out how to get it inline with where the yellow stud shooter barrel meets the new female CV joint. The wheels and tires are the same as on the image above.

Edited February 12, 2020 by SNIPE

[suffocation]

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Edited February 13, 2020 by suffocation
Content removed to make room for gargantuanly, mastodontically superior digital designs.

[Magical Duck]

@suffocation perhaps that works, but they still want suspension without the use of the turntable in the middle 

[suffocation]

2 hours ago, Magical Duck said:

@suffocation perhaps that works, but they still want suspension without the use of the turntable in the middle 

Okay, I'll remove it.

[sirslayer]

Well after a long fought battle, the turntable is the best and compact solution for a mini 4x4x4 chassis and I'll provide a few ideas to improve and the outcome..    First of all, I had an idea of using the rubber flex hose/tubes and create a stitch between the 5x7 frame element with an axle and protective bushing using the flex tubes.  I like how the tubes held it together and it can be used as suspension at the same time but if you compared it to the mini- turntable solution,.. The turntable s really reliable and very compact.. I like how the body can almost do a 180 degree turn before the steering gets binded up.. Wow!!!

Lego techic 4x4x4 by victormendoza_jr, on Flickr

Lego techic 4x4x4 by victormendoza_jr, on Flickr

And the low profile is to much to ignore!! 

Lego techic 4x4x4 by victormendoza_jr, on Flickr

[Jurss]

Interesting, how everything will be attached to frame?

[SNIPE]

Thanks for all the replies,

I have decided to wait until I get the physical parts from bricklink so that I can see exactually how it will steering and what not then I can think of the best way to design it using the ideas in this topic.

Regards, S