motor to lego shaft
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// Axle/Hub for Lego wheel. // Connects M3 motor shaft on Tajima motor/gearbox kit to Lego splined axle wheel. // // Printed at 0.2mm layers on UP!. Build 45degree overhangs with no support // // Motor shaft hole can be HEX, ROUND, or ROUND with FLAT // Using metal hex threaded standoff for M3 connection // standoff is M3x10mm x5mm across flats JAYCAR HP0900 // standoff is press fit into hex hole. Hole has domed ceiling so prints without support // // Lego axle design has keyholing to get cleaner inner corners than a simple cross, on the UP // Has provision for two Flanges that can directly engage the inner surfaces of the wheel rim to provide support // as the printed axle is prone to shearing under load. // It is intended that the flange/s are interference fit into the hub parts, // and that the wheel is forced all the way down the axle to the flange so the axle is not cantilevered // Intended for insertion from the deep side of the wheel hub //-------- Dimension Constants ------------ //R???? = radius, L???? = length; Note small numbers added to dimensions are used to trim for exact fit with your printer (eg +0.1) LSpline = 10 + 2; //Spline is the Lego Axle part //AQUA Flange1 closest to spline RFlange = (8 + 0.1) / 2; //Flange1 is adjacent to the axle spline LFlange = 4.3; //TEAL Flange 2 is optional where it needs a large ring spaced off the axle by Flange1 //Type2 Hub - Red/Orange Balloon tyres, double flange; Also works for Black wheels RFlange2 = (16 + 0.1) / 2; LFlange2 = 6; // Type1 Hub - Black, flat tyres, only 1 small flange //RFlange2=RFlange; //LFlange2=0.01; HoleOS = 0.6 / 2; // Oversize holes to get to correct size. (UP usually makes holes small) HoleIsHex = false; HoleFlat = 0; //For round motor hole with flat on one side. Depth of flat from outside LHole = 10; //Hex threaded insert dimensions RHole = 1.6 + HoleOS; //For hex holes is distance across flats (apothem) //MAGENTA Shaft is part holding hex from motor end RShaft = 8 / 2; LShaft = LHole ; RHex = Apothem2Radius(RHole, 6); //dimension across diagonals //----- function Apothem2Radius(apothem, n) = apothem / cos(180 / n); use < MCAD / regular_shapes.scad > //-------------------- Lego Axle ---------------------- axle_spline_width = 2.0 - 0.2; axle_diameter = 4.8 - 0.1; axle_inner_keyhole_radius = 0.3; //keyhole the corners to try and make them square when printed module axle(height) { translate([0, 0, height/2 - LShaft]) difference() { union() { cube([axle_diameter, axle_spline_width, height], center = true); cube([axle_spline_width, axle_diameter, height], center = true); } //union for (A = [0, 90, 180, 270]) { rotate([0, 0, A]) { translate([axle_spline_width / 1.75, axle_spline_width / 1.75, 0]) cylinder(h = height + 0.01, r = axle_inner_keyhole_radius, center = true, $fs = 0.2); } //rot } //for } //translate diff } //module //----------------------------- Main --------------------------------- difference() { union() { //the solid bits color("magenta") cylinder(h = LShaft, r = RShaft, $fn = 50); translate([0, 0, LShaft]) { color("teal") cylinder(h = RFlange2 - 2, r2 = RShaft - 3, r1 = RShaft, $fs = 1); // translate([0, 0, LFlange2]) { translate([0, 0, LFlange]) axle(height = LSpline); } } } //union union() { //the holes translate([0, 0, -0.05]) { cylinder(r1 = RHole * 1.2, r2 = RHole * 0.8, h = RHole * 0.4, center = false); //entry countersink if (HoleIsHex) { hexagon_prism(height = LHole, radius = RHex); //hole for hex spacer } else { intersection() { //to put a flat on side of round shafts cylinder(r = RHole, h = LHole, $fn = 20); translate([-RHole, -RHole - HoleFlat, 0]) cube([2 * RHole, 2 * RHole, LHole]); } //intersect } //if translate([0, 0, LHole - 0.01]) cylinder(h = RHole, r1 = RHole, r2 = 0.5); //put a cone on top of hole so no support needed } } //union } //diff |
