simon/tricycle-mechanical-design
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Well, the nose is too long, and there are other problems with the hull,

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but that's a visualisation that works.
This commit is contained in:
Simon Brooke 2025-09-16 21:10:10 +01:00
parent 3b90a2e4d5
commit b95f639c30
5 changed files with 73 additions and 11 deletions
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6
model/fourbar.scad
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@ -3,9 +3,9 @@
// (c) Simon Brooke 2025; CC-BY-SA
include <BentSim/Library/Bike_accessories.scad>
include <NACAAirfoils/files/Naca4.scad>
include <library/skew.scad>
include <wheel.scad>
module fourbar_leg(length=1000, chord=100, long_skew=30, lat_skew=30) {
h = length * cos(lat_skew) * cos( long_skew);
@ -47,8 +47,8 @@ module fourbar_axle_half( length, chord) {
// wheel
translate([0, length + 50, -50])
// Pierre Rouzeau's wheel is beautifully modelled and parameterised, but it doesn't seem to be scaled as I'd expect...
wheel(rim=451, spoke_nbr=32);
rotate([270, 0, 0])
wheel(iso=451);
}

2
model/hull.scad
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@ -64,4 +64,4 @@ module hull() {
}
}
hull();
//hull();

7
model/subframe.scad
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@ -2,18 +2,17 @@
// (c) Simon Brooke 2025; CC-BY-SA
include <BentSim/Library/Bike_accessories.scad>
include <SprocketGenerator2/files/Sprocket_Generator_v2_example_10.scad>
include <wheel.scad>
include <chainset.scad>
include <epicyclic.scad>
module subframe_cycleparts(rim=451, chainring_teeth=82, crank=140) {
// wheel
translate([0, 382, 93])
rotate([0, 0, 90])
wheel(rim=rim, spoke_nbr=0);
rotate([0, 90, 0])
wheel(iso=rim);
translate([-42, 382, 93])
rotate([0, 90, 0])

8
model/tricycle.scad
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@ -6,15 +6,17 @@
include <subframe.scad>
include <fourbar.scad>
//include <hull.scad>
include <hull.scad>
rotate([0, 0, 270])
translate([0, 1200, 180])
subframe(structure="carbon");
translate([0,-50, 320])
translate([0, 0, 320])
fourbar(700, 100, 30, 35, 650);
//hull();
translate([500, 0, 100])
rotate([0, 3, 0])
hull();
/*
prop=0.1;

61
model/wheel.scad Normal file
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@ -0,0 +1,61 @@
// 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();