7-Wide axle with centre-point and Ackermann steering

[Junpei]

Hello!

Today I'd like to present my idea for an axle I made, probably most ideal for small MOCs and model team trucks. A couple pictures, front and back (please ignore the 7L beam with the wheel on the end, I used it to prop it up so I could take photos :P )

The two links on each side allow the pivot point to be projected outwards, creating a pivot very close to the center of the wheel, and somehow it also has Ackermann geometry (tbh, the ackermann was not even intentional, I was ecstatic and very surprised when I first steered it ) Steering is done by rotating the cam you see in the middle of the axle.

Well, I think that about covers it. I hope you enjoy it, and feel free to incorporate it into any MOCs if you wish.

Happy building,

Junpei

[Hrafn]

Thank you for sharing this, it's quite ingenious.

[Rockbrick]

very ingenious and very useful for small narrow busses and the like, but I fail to see how this can be 'Centre point' steering

[Junpei]

@Rockbrick: I apologize for the misleading title, it's nearly centre-point steering. Almost a stud closer to the centre of the wheel than you would get with e.g. this as a kingpin.

Here's a picture showing it:

Because of the perspective, it's a little bit off (it's a little bit farther out, possibly even truly centre-point, this picture is just demonstrating the concept).

Junpei

[Rockbrick]

Yes sorry, you are right, I see it now - I guess I should have tried to make it first and try it out before commenting.... I apologise. Though true centre point is only possible with the pivot inside the hub (almost impossible to do it sturdy enough with lego) like on the citroen DS:

[Infraredbrick]

Though true centre point is only possible with the pivot inside the hub (almost impossible to do it sturdy enough with lego)...

I respectfully disagree. This was done a couple years ago by a builder named Ricardo Oliveira, who was using an idea from fellow builder sunsky:

And this is my version with Ackermann:

Kudos to the OP on a good design!

Edited January 10, 2015 by Infraredbrick

[Hrafn]

True centerpoint steering can also be done at larger scales by using thin wheels, custom hubs, and some steering axis inclination (SAI, aka kingpin inclination). My Lancia 037 had near-center-point steering using 62.4x20 wheels, custom hubs, and Short/Long Arm (SLA) suspension (5 studs on the top, 6 on the bottom) to give some SAI. My current project is about ~14 studs wide and has center point steering or close to it (the theoretical scrub radius is about negative 1mm) using a MacPherson setup.

[DrJB]

Nicely done. You could also add 'multi-link' in the description, as the kingpin axis is beyond/outside the joints.