After fixing my printer which had a silly adjustment problem that took me 2 days to find annd fix, here we have the Lego wheel hub
First a twin wheel approach using the lego hubs to show the width
To explain the design approach, first I designed the axle fitting
Having got that right I incorporated that into the hub design and presto
There are the three wheels, on the right the lego wheel
on the left the HL wheel
and in the middle the new wheel with Lego tyre
and here's the scad code
module hub () {
difference () {
union () {
translate ([0,0,-3])cylinder(h = 18, r = 17, $fn=80);
translate ([0,0,-3])cylinder(h = 1.5, r = 19, $fn=80);
translate ([0,0,13.5])cylinder(h = 1.5, r = 19, $fn=80);
translate ([0,0,0])cylinder(h = 1.5, r = 21.5, $fn=80);
translate ([0,0,10.5])cylinder(h = 1.5, r = 21.5, $fn=80);
}
translate ([0,0,-3.5])cylinder(h = 19, r = 15.5, $fn=80);
}
difference () {
union () {
translate ([0,0,9])cylinder(h = 2, r = 17, $fn=80);
translate ([0,0,10.5]) cylinder(h = 2, r1 = 10, r2=9, $fn=80);
}
translate ([0,0,-3.5])cylinder(h = 19, r = 4, $fn=80);
}
translate([4,-1,1]) cube ([13,2,8]);
rotate ([0,0,120])translate([4,-1,1]) cube ([13,2,8]);
rotate ([0,0,240])translate([4,-1,1]) cube ([13,2,8]);
}
module hub_centre () {
difference () {
union () {
translate ([0,0,0])cylinder(h = 12, r = 4.5, $fn=80);
translate ([0,0,12])cylinder(h =3, r = 4, $fn=80);
}
translate ([0,0,0])cylinder(h = 16, r = 1.3, $fn=80);
translate ([0,0,11])cylinder(h = 16, r = 2.7, $fn=80);
}
}
module axle (){
translate([-3,-1.5,-0.1]) cube ([6,3,10]);
rotate ([0,0,60])translate([-3,-1.5,-0.1]) cube ([6,3,10]);
rotate ([0,0,120])translate([-3,-1.5,-0.1]) cube ([6,3,10]);
}
hub () ;
difference () {
hub_centre ();
axle();
}
That's it folks. Copy the code into openscad,
http://www.openscad.org/
generate the stl, and you too can have a hub to fit a lego tyre to a heng long truck
The print time is about 1.5 hours at fairly low quality (as you can see) but it's a complex print.
Obviously it needs wheel nuts and fancy bits but that you can add as desired to match your build.
Have fun
Alwyn