tricycle-mechanical-design/model/wheel.scad
2025-09-16 21:10:10 +01:00

61 lines
1.6 KiB
OpenSCAD

// wheel.scad
// I don't actually need spoked wheels
// ISO standard numbers refer to the tyre bead diameter in
// millimetres; the outer diameter of the rim is about 14mm
// more. Rim width varies but 22mm is common. The wheel sizes
// I'm interested in are ISO 406 and ISO 451. Fronmt hubs (and
// the hubs I'm planning to use are all front hubs) typically
// have an over locknut dimension of 100mm, but the lefties,
// which I plan to use, are narrower: 50mm flange to flange, and
// 65mm overall (with a 5mm spacing to the inner side of the
// fork leg).
//
// Outer diameter over the inflated tyre is obviously larger than
// the rim diameter but how much larget depends on the tyre;
// for road tyres, 20mm seems about typical.
module wheel (iso=451) {
radius=(iso/2)+7;
// rim
color("grey")
difference() {
cylinder(h=22, r=radius, center=true);
translate([0,0, -11])
cylinder(h=26, r=(radius-10));
}
// carbon cones covering the spokes
color("black")
translate([0,0, 4])
cylinder(h=26.6, r1=radius, r2=22.5);
color("black")
mirror([0, 0, -1])
translate([0,0, 4])
cylinder(h=14.4, r1=radius, r2=29);
// tyre
color("black")
rotate_extrude(convexity = 10)
translate([radius +10, 0, 0])
circle(r = 12, $fn = 100);
// hub
color("grey")
translate([0, 0, -40])
cylinder(h=65, r=22.5);
// axle
color("silver") {
translate([0, 0, -45])
cylinder(h=70, r1=12.5, r2=7.5);
translate([0, 0, -85])
cylinder(h=40, r=12.5);
}
}
// wheel();