Started work on microcar suspension

microcar/suspension.scad

@@ -0,0 +1,109 @@
+/**
+ * suspension.scad
+ *
+ * First sketch of a microcar suspension subframe.
+ *
+ * The purpose of the subframe is sumply to carry the inner ends of the
+ * wishbones, so it is simply the minimum size required to do that.
+ */
+ 
+ // assumes we're building out of square section aluminium tobe;
+ // the section width of that tube.
+ stock_section = 25;
+ 
+ lug_thickness = stock_section/6;
+ 
+ // radius of suspension pivots
+ pivot_radius = stock_section/3; //for now
+ 
+ module lug() {
+    difference() {
+         union() {
+             translate([0, stock_section/2, 0]){
+                cube([ stock_section, stock_section, lug_thickness], center=true);
+             }
+             
+             cylinder( r=stock_section/2, h=stock_section/4, center=true);
+                 
+         }
+         cylinder( r=pivot_radius, h=stock_section, center=true);
+     }
+}
+ 
+ module wishbone(l, w) {
+     ssd2 = stock_section/2;
+     ssm2 = stock_section * 2;
+     ssm3 = stock_section * 3;
+     
+     translate([ (l - lug_thickness)/2, stock_section, ssd2])
+         rotate([180,90,0])
+            lug();
+     translate([ 0 - (l - lug_thickness)/2, stock_section, ssd2])
+         rotate([180,90,0])
+            lug();
+     
+     color("silver")
+     union() {
+         intersection(){
+             linear_extrude(stock_section)
+                polygon( points=[[0-(l/2), ssd2], [l/2, ssd2],
+                        [3*ssd2, w-(3*ssd2)], [0-(3*ssd2), w-(3*ssd2)],
+                        // hole in the middle
+                        [0-(l/2 - 3*ssd2), 3*ssd2],
+                        [l/2 - 3*ssd2, 3*ssd2],
+                        [ssd2, w-(5*ssd2)], [0-ssd2, w-(5*ssd2)]], 
+                    paths=[[0, 1, 2, 3], [4, 5, 6, 7]]);
+            translate([0 - (l - ssd2)/2, 0, 0 - stock_section])
+                cube([l-ssd2, w, ssm3]);
+         }
+         translate([-3*ssd2, w-3*ssd2, 0])
+            cube( [stock_section, 3*ssd2, stock_section]);
+         translate([ssd2, w-3*ssd2, 0])
+            cube( [stock_section, 3*ssd2, stock_section]);
+    };
+    color("darkgray")
+    translate([0, stock_section, ssd2])
+        rotate([0, 90, 0])
+            cylinder(h=l, r=pivot_radius, center=true);
+    color("darkgray")    
+    translate([0, w - ssd2, ssd2])
+        rotate([0, 90, 0])
+            cylinder(h=ssm3, r=pivot_radius, center=true);
+    
+}
+ 
+ module subframe(l, w, h) {
+     q = stock_section * 2;
+     color( "silver")
+     difference() {
+         cube([l,w,h], center=true);
+         cube([l+200, w-q, h-q], center=true);
+         cube([l-q, w+200, h-q], center=true);
+         cube([l-q, w-q, h+200], center=true);
+     }
+ }
+ 
+ module suspension( l = 300, w = 300, h = 300,
+        track = 1400, hub_width = 135, wheel_diameter=600) {
+     subframe(l,w,h);
+     
+     // Upper wishbones
+     translate([0, w/2, (h/2) - stock_section])
+        wishbone( l, 500);
+     mirror([0,1, 0]) {
+         translate([0, w/2, (h/2) - stock_section])
+            wishbone( l, 500);
+     }
+
+      // lower wishbones
+     translate([0, w/2, 0 -(h/2)])
+        wishbone( l, 500);
+     mirror([0,1, 0]) {
+         translate([0, w/2, 0 -(h/2)])
+            wishbone( l, 500);
+     }
+ }
+ 
+ lug();
+ 
+suspension();

microcar/tub.scad

@@ -11,7 +11,11 @@ bb_width = 260;     // internal width of battery box
  * moment I'm making the simlifying assumption that it
  * is horizontal.
  ****************************************************/
-cowl_height = 550;  
+
+// slope of the cowl
+cowl_angle = -70;
+// maximum height of the cowl (at the A pillar)
+cowl_height = 450;  
 
 floor_length = 1100;
 floor_width = 1500;
@@ -21,8 +25,10 @@ floor_width = 1500;
  * which bonds to the front or rear bulkhead from the
  * layback angles, but I'm being lazy for now
  ****************************************************/
-layback_angle_f = 60;
+// angle of the front bulkhead to vertical
-layback_angle_r = 60;
+layback_angle_f = 30;
+// angle of the rear bulkhead to vertical
+layback_angle_r = 45;
 
 sheet_thickness = 8;
 sill_max_height = bb_height;
@@ -31,27 +37,31 @@ sill_width = 150;
 
 module battery_box_side( floor_length = 1100) {
     fhl = (floor_length/2);
-    top_hl = 800; // calculate this later
+    top_hlf = (bb_height * tan(layback_angle_f)) + fhl;
+    top_hlr = (bb_height * tan(layback_angle_r)) + fhl;
     rotate([90, 0 , 0])
         linear_extrude( height=sheet_thickness) {
             polygon([[ 0 - fhl, 0], 
                 [ fhl, 0], 
-                [ top_hl, bb_height],
+                [ top_hlr, bb_height],
-                [ 0 - top_hl, bb_height]]);
+                [ 0 - top_hlf, bb_height]]);
         }
 }
 
 module battery_box( floor_length = 1100) {
     top_hl = 800; // calculate this later
     hbbw = bb_width/2;
+    bias = (layback_angle_f == layback_angle_r) ? 0 : bb_height * ( tan(layback_angle_r) - tan(layback_angle_f))/2;
+    
     translate([0, hbbw, 0])
         battery_box_side( floor_length);
     translate([0, 0 - (hbbw + sheet_thickness), 0])
         battery_box_side( floor_length);
     translate([0, 0 - hbbw, 0])
         cube([sheet_thickness, bb_width, bb_height]);
-    translate([0, 0 - sheet_thickness, bb_height])
+    translate([bias, 0 - sheet_thickness, bb_height])
-        cube([1600, bb_width + (sheet_thickness * 2),
+        cube([floor_length + (bb_height * tan(layback_angle_f)) +
+        (bb_height * tan(layback_angle_r)), bb_width + (sheet_thickness * 2),
             sheet_thickness],
         center = true);
 }
@@ -59,13 +69,14 @@ module battery_box( floor_length = 1100) {
 module sill( floor_length = 1100) {
     cr = 5000;
     fhl = (floor_length/2);
-    top_hl = 800; // calculate this later
+    top_hl = fhl + (cowl_height * tan(layback_angle_f)); 
+    top_hlr = fhl + (sill_max_height * tan(layback_angle_r));
     difference() {
         rotate([90, 0 , 0])
             linear_extrude( height=sill_width) {
                 polygon([[ 0 - fhl, 0], 
                     [ fhl, 0], 
-                    [ top_hl, sill_max_height],
+                    [ top_hlr, sill_max_height],
                     [ 0, sill_min_height],
                     [ a_pillar_y, sill_min_height],
                     [ a_pillar_y, cowl_height],
@@ -79,6 +90,14 @@ module sill( floor_length = 1100) {
 }
 
 module front_bulkhead() {
+    e = cowl_height / cos(layback_angle_f);
+    
+    translate([ 0 - floor_length/2, 0 -floor_width/2, 0])
+    rotate([0, 0- layback_angle_f, 0])
+    cube([sheet_thickness, floor_width, e]);
+}
+
+module rear_bulkhead() {
 }
     
 
@@ -94,3 +113,4 @@ mirror([0, 1, 0])
         ( floor_width/2) + (sill_width/2), 0])
         sill();
 
+front_bulkhead();