154 lines
4.7 KiB
OpenSCAD
154 lines
4.7 KiB
OpenSCAD
/**
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* suspension.scad
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*
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* First sketch of a microcar suspension subframe.
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*
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* The purpose of the subframe is sumply to carry the inner ends of the
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* wishbones, so it is simply the minimum size required to do that.
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*
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* TODO: this does not yet consider caster, camber, anti-dive geometry,
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* or other such niceties.
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*/
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include <BOSL2/std.scad>
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include <shockabsorber.scad>
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include <wheel.scad>
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// assumes we're building out of square section aluminium tobe;
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// the section width of that tube.
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stock_section = 25;
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lug_thickness = stock_section/6;
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// radius of suspension pivots
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pivot_radius = stock_section/3; //for now
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module lug() {
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difference() {
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union() {
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translate([0, stock_section/2, 0]){
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cube([ stock_section, stock_section, lug_thickness],
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center=true);
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}
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cylinder( r=stock_section/2, h=stock_section/4,
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center=true);
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}
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cylinder( r=pivot_radius, h=stock_section, center=true);
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}
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}
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module wishbone(l, w, is_upper = true) {
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ssd2 = stock_section/2;
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ssm2 = stock_section * 2;
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ssm3 = stock_section * 3;
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// wishbone inboard pivot lugs
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translate([ (l - lug_thickness)/2, stock_section, ssd2])
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rotate([180,90,0])
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lug();
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translate([ 0 - (l - lug_thickness)/2, stock_section, ssd2])
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rotate([180,90,0])
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lug();
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// shock absorber end lugs
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if (is_upper) {
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translate([ ssd2, ssm2, ssd2])
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rotate([180,90,0])
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lug();
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translate([ -ssd2, ssm2, ssd2])
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rotate([180,90,0])
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lug();
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} else {
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translate([ ssd2, w-ssm3, ssd2])
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rotate([180,90,180])
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lug();
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translate([ -ssd2, w-ssm3, ssd2])
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rotate([180,90,180])
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lug();
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}
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color("silver")
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union() {
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intersection(){
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linear_extrude(stock_section)
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polygon( points=[[0-(l/2), ssd2], [l/2, ssd2],
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[3*ssd2, w-(3*ssd2)],
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[0-(3*ssd2), w-(3*ssd2)],
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// hole in the middle
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[0-(l/2 - 3*ssd2), 3*ssd2],
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[l/2 - 3*ssd2, 3*ssd2],
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[ssd2, w-(5*ssd2)], [0-ssd2, w-(5*ssd2)]],
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paths=[[0, 1, 2, 3], [4, 5, 6, 7]]);
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translate([0 - (l - ssd2)/2, 0, 0 - stock_section])
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cube([l-ssd2, w, ssm3]);
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}
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translate([-3*ssd2, w-3*ssd2, 0])
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cube( [stock_section, 3*ssd2, stock_section]);
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translate([ssd2, w-3*ssd2, 0])
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cube( [stock_section, 3*ssd2, stock_section]);
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};
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color("darkgray")
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translate([0, stock_section, ssd2])
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rotate([0, 90, 0])
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cylinder(h=l, r=pivot_radius, center=true);
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color("darkgray")
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translate([0, w - ssd2, ssd2])
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rotate([0, 90, 0])
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cylinder(h=ssm3, r=pivot_radius, center=true);
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}
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module subframe(l, w, h) {
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q = stock_section * 2;
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color( "silver")
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difference() {
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cube([l,w,h], center=true);
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cube([l+200, w-q, h-q], center=true);
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cube([l-q, w+200, h-q], center=true);
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cube([l-q, w-q, h+200], center=true);
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}
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}
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module suspension( l = 300, w = 300, h = 300,
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track = 1400, hub_width = 135, wheel_diameter=600) {
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subframe(l,w,h);
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wishbone_length = 500; // TODO: calculate
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// Upper wishbones
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translate([0, w/2, (h/2) - stock_section])
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wishbone( l, wishbone_length);
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mirror([0,1, 0]) {
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translate([0, w/2, (h/2) - stock_section])
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wishbone( l, wishbone_length);
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}
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shock_extent = wishbone_length - (5.5 * stock_section);
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shock_angle = atan(shock_extent/(h-stock_section));
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shock_length = shock_extent * tan(shock_angle);
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// lower wishbones
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translate([0, w/2, 0 -(h/2)]) {
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wishbone( l, wishbone_length, false);
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translate([0, wishbone_length + 75, stock_section])
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wheel();
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translate([0, (stock_section*2), h-(stock_section/2)])
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rotate([shock_angle +180, 0, 0])
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shockabsorber(length=shock_length,eid=stock_section/2);
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}
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mirror([0,1, 0]) {
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translate([0, w/2, 0 -(h/2)]) {
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wishbone( l, wishbone_length, false);
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translate([0, wishbone_length + 75, stock_section])
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wheel();
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translate([0, (stock_section*2), h-(stock_section/2)])
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rotate([shock_angle +180, 0, 0])
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shockabsorber(length=shock_length,
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eid=stock_section/2);
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}
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}
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}
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// suspension();
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