Mechbuilds Projects

[sirslayer]

well the Lego set 8081 haves a very strong rear axle!! its on a swing arm!! or even the 40th anniversary model haves a simple independent rear suspension..  if youre basing off from Paave's .. look into the 8081 set!! 

[Mechbuilds]

2 hours ago, sirslayer said:

well the Lego set 8081 haves a very strong rear axle!! its on a swing arm!! or even the 40th anniversary model haves a simple independent rear suspension..  if youre basing off from Paave's .. look into the 8081 set!! 

I studied the axle and it only has up and down movement.. It cannot twist side to side. 

[Mechbuilds]

The only way i could make an independent rear axle design is with a floating differential. But i'd need to order this part:

But even then, i couldn't make it a lockable differential in that scale since the axle can be at maximum 13 studs wide between the tires. 

I think i'll have to go with a live axle instead. This moc is beginning to get pretty heavy. 
The cab is 0.6 kg's already. 

[Mechbuilds]

It's so frustrating to design a working suspension.. 

Here are some of the mockups i've done..


Not sure if that would work..

That definitely didn't work.

Otherwise great but too high for the truck.. The suspension would be mounted trough the truck flat bed..


The axle itself:



It's very robust and durable.. It can handle the buwizz power easily without breaking any parts.. However, it's a complete nightmare to hang on the chassi for the truck.. 
Main issues are: 
13 studs wide from tire to tire <-- Very compact means either it's too brittle and it breaks and twists or it's very hard to implement to the chassi with a suspension. 
Low mounting points. The chassis itself is very low.. Only 10 studs until it hits the truck flatbed. 
Independent but non driven front axle with great steering. <-- The rear axle needs to be preferably locked diff for offroading or drifting. (if possilbe with tape over the tires to reduce grip.)

This is a rally truck.. It's designed to be silly. I couldn't make it 4wd without either having the steering lock very low due to cv joint limited travel.. Or not durable enough, using U joints you can get more cowbell but to build it with these tyres i have, you can't get the axle durable enough without parts bending or loosening on use.. 



After i'm done with this moc, i might order bigger tires and a pair of portal hubs cause making mocs on this small scale is difficult as hell. 

Edited September 13, 2019 by Mechbuilds

[sirslayer]

You can always download the Lego 42099 instructions and study the front suspension on that set!!  

[Mechbuilds]

EDIT: No longer relevant

Edited November 29, 2019 by Mechbuilds

[Mechbuilds]

I'm thinking about making a snow cargo vehicle using CLAAS tyres. 

While i'm waiting forever to receive parts for the @efferman's dump truck moc. I got inspired to make something after it's done. 
What i want to make is a snow expedition cargo vehicle that's futuristic.

Features: 
-4x4. 
-Cargo space
-High ground clearance. (portal axles on all 4 perhaps.)
-BuWizz

It will be roughly the same size as the dump truck. But a little bit higher. 
It will be driven on snow so my goal is to get the electronics higher so they don't get wet. 

Should i go for independent suspension or live axles?  Two XL motors spinning all tires or one XL motor for front axle and one XL motor for rear axle? 

I'm kind of leaning toward independent axles and one XL for each axle simply because it will provide high torque and a more simple drivetrain for an 4x4. 
Since i'm going on snow on Claas tyres that are flipped backwards for grip, do i really need to have diffs? 


If anybody can help me with the axles, i'd appreciate it. 
-Axles need to be 21 studs wide. (between tyres)
-If it has a diff, it needs to be lockable. (Manual or electronic. Both works. Buwizz has 4 places for motors. One is occupied for steering.)
-Portal axles using legos portal hubs? 
-Small springs only. (I don't have long springs)

The moc will be around 45 studs long. 

[Mechbuilds]

My progress with the @efferman's dump truck:



Still desperately waiting for parts.. 

[Mechbuilds]

Modified to work with buwizz. However anything over normal mode will destroy the U joint instantly which is near the rear axle. 
I think the rear axle should be mounted with a turntable and only have sideways swing and no up and down movement. That would increase playability. 


I will probably start modifying this beast into the "little truck that could".. Perhaps removing the bucket and adding a snow plow and make it the biggest snow plow ever? 
So many possibilities.. 

[Maaboo the Witch]

On 11/29/2019 at 4:52 PM, Mechbuilds said:

I'm thinking about making a snow cargo vehicle using CLAAS tyres. 

While i'm waiting forever to receive parts for the @efferman's dump truck moc. I got inspired to make something after it's done. 
What i want to make is a snow expedition cargo vehicle that's futuristic.

The 42070 B-model is a good place to begin:

Reasonably high ground clearance and CLAAS tyres, for starters. The panels used on the Liebherr truck would make great body panels as well.

[Mechbuilds]

14 minutes ago, Maaboo35 said:

The 42070 B-model is a good place to begin:

Reasonably high ground clearance and CLAAS tyres, for starters. The panels used on the Liebherr truck would make great body panels as well.

Interesting.. What modification i'd do to the snow cargo vehicle would be a snow plow on the front. 
Main points are as high as ground clearance i can get and electronics as far top as i can make it while still being heavyish so it can move easily on snow. The snow plow needs to be easily removed so i can crawl with it on snow tracks i can make. 
I don't want snow touching my motors or electronics. Probably the best way to work it out is placing the motors upside down and having those 4 spoke gears to turn the torque 90 degrees for both axles. That way the motors could be even higher and safe from water. 

I'm already working on a front axle with portal axles. Just need to make it sturdier. 

[Mechbuilds]

My current progress on the front axle for my next moc:



Very big thank you to @Madoca 1977 for helping me out on this axle.

Edited December 16, 2019 by Mechbuilds

[Mechbuilds]

Update:



Here we have the front axle assembly coming along.. I added a gearbox inside the H frames to turn the engine 90 degrees toward the diff by using knob gears. 
Not sure if it was the best call to have it built this way. But the XL motor should be 6 studs long so it should be at the H frames height. 

If anybody can figure out a better or more compact way to do it then i'm all ears. (And i mean height. It's already very very tall.) 
My original thought was to mount the XL motor on top of the differential as it would make the structure one stud lower. But i can't figure out how.. 
Would be great if there was more gearing reduction. Currently it's 3:1 


If somebody has a way to mount the XL motor on top of the diff and build a small gearbox that reduces it even further then i'd rather build that. 

EDIT:


This is one way i thought about it.. But it won't reduce any gearing.. 

Ideas?

Edited December 19, 2019 by Mechbuilds

[Mechbuilds]

Could anybody help me out with a gearbox to allow the XL motor to be mounted like in the picture? 
 

[Mechbuilds]

I guess this could solve the gearing problem. But mounting the motor and gearbox so it's durable is another thing. 

[Mechbuilds]

Axles front and back. 

Should make it all wheel steering like in the picture or have the rear axle as a normal axle without steering? 
One solution would also be to just add a second servo if somebody would sell me one for less than 50€.. 

I'm thinking about if i should keep it this way or add a turntable in the middle? 
It's starting to be more of a crawler now haha. 

[Mechbuilds]

It's a rough guesstimate where the springs should be mounted.. I'm going to lose half stud of clearance but in exchange i will gain full range of suspension travel from the front axle arms. 

Also for the servo, if i mount it upwards and use gears to turn it 90 degrees, it will have some slack which i don't want. 
Also it can't be mounted on top of the H beam because it will interfere with the springs. 
Springs can't be mounted on the ball cup arm because it will pop it off from it's socket. 

[Void_S]

On 12/21/2019 at 6:13 PM, Mechbuilds said:

I guess this could solve the gearing problem. But mounting the motor and gearbox so it's durable is another thing. 

This scheme is very similar to 9398's Crawler one. I believe you can borrow some embracing solutions for the gears and driveshafts.

[Mechbuilds]

Thanks for the tip. I'm going to try the front bracing idea. It seems to be solid. 

EDIT:

Edited December 28, 2019 by Mechbuilds

[Mechbuilds]

It doesn't work. The suspension is too frail from the ball joint mounts and also the suspension is a nightmare to attach properly.. 
I think i'll have to scrap this and go for a stiff axle instead. 

[suffocation]

Daymn, why did I miss this?

Looks good - what are you stuck on exactly?

[Mechbuilds]

11 hours ago, suffocation said:

Daymn, why did I miss this?

Looks good - what are you stuck on exactly?

The axle had so many problems under heavier weight that i had to scrap it. 
I made a post on the axle collection thread asking for advice on the stiff axle. 



 

[suffocation]

Ah, I see now. The next-to-last picture you posted has the springs vertical, which causes them to sag very easily. Have you got enough room to get them at an angle? Two hard springs at more or less a 30° per each of four wheels should handle 3 kg pretty easily.

Otherwise you could resort to a torsion bar or a solution to the same effect, which would likely take up less room.

What are your trackbase and track width limits? I've got a few axles that might work.

[Mechbuilds]

35 minutes ago, suffocation said:

Ah, I see now. The next-to-last picture you posted has the springs vertical, which causes them to sag very easily. Have you got enough room to get them at an angle? Two hard springs at more or less a 30° per each of four wheels should handle 3 kg pretty easily.

Otherwise you could resort to a torsion bar or a solution to the same effect, which would likely take up less room.

What are your trackbase and track width limits? I've got a few axles that might work.

The issue on the old axle was this:


The ball socket stud keeps being pushed out from it due to weight on top of the axle. 
I need an axle that's very sturdy. A motor mounted on axle pendular build works better. It can handle infinite weight and you can use springs to center the body/chassis on top. 

If the build was smaller, the axle would have been handy with a medium motor and different gearing. 


If anybody wants to tinker around with the old axle, here's the .LXF

Edited January 6, 2020 by Mechbuilds

[suffocation]

If you want a pendular axle then something like this could work. I used it - two of them, in fact - on my very first rough terrain crane, which weighed over 4 kg. The springs are pivot-mounted, so the actual suspension range is around 5 studs per side.

(sorry about the projectile-puke pics and clumsy build - was even further behind in my learning.)

Edited January 6, 2020 by suffocation