Merge pull request #91 from skeptonomicon/master

fixed rack, fixed test_gears, and added spoked gears

involute_gears.scad

@@ -303,8 +303,15 @@ module gear (
     rim_width=undef,
     hub_thickness=undef,
     hub_diameter=undef,
+    spokes=0,
+    spoke_width=undef,
+    spoke_thickness=undef,
+    spoke_square=false,
+    centered_gear=false,
+    centered_hub=false,
     bore_diameter=undef,
     circles=0,
+    circle_diameter=undef,
     backlash=0,
     twist=0,
     involute_facets=0,
@@ -350,29 +357,43 @@ module gear (
     rim_width = (rim_width!=undef?rim_width:root_radius * .1);
     rim_radius = root_radius - rim_width;
 
-	// Variables controlling the hub_diameter
+    // Variables controlling the hub
     hub_thickness = (hub_thickness!=undef?(hub_thickness!=0?hub_thickness:gear_thickness):gear_thickness * 2);
     hub_diameter = (hub_diameter!=undef?hub_diameter:root_radius * .3);
+    hub_base = (centered_hub == false)? 0 : rim_thickness/2 - hub_thickness/2;
+
+    // Variables controlling the spokes
+    spokes = spokes == undef? 0 : spokes;
+    spoke_thickness = (spoke_thickness == undef)? rim_thickness : spoke_thickness;
+    spoke_width = (spokes==0)? 1 : (spoke_width == undef)?  0.75 * pi * hub_diameter / spokes : spoke_width; 
+    //spoke_depth is depth spoke must penetrate into hub to ensure complete penetration
+    spoke_depth = ((hub_diameter/2)^2-(spoke_width/2)^2)^0.5 +.01;
+    //spoke length is length of spoke including the depth sunk into the hub
+    spoke_length = spoke_depth+rim_radius-(hub_diameter/2.0);
+    //spoke raius is the distance from gear center to base of the spoke(inside the hub)
+    spoke_radius = (hub_diameter/2.0)-spoke_depth;
+    //echo (str("spoke_width: ",spoke_width,", hub_diameter: ",hub_diameter, ", spoke_depth: ",spoke_depth));
     
     // Variables controlling the bore
-	bore_diameter = (bore_diameter!=undef?bore_diameter:root_radius * .1);
+    bore_diameter = bore_diameter!=undef?bore_diameter:root_radius * .1;
 
     // Variables controlling the circular holes in the gear.
     circle_orbit_diameter=hub_diameter/2+rim_radius;
     circle_orbit_curcumference=pi*circle_orbit_diameter;
 
     // Limit the circle size to 90% of the gear face.
-	circle_diameter=
+    circle_default_diameter = min (
-		min (
         0.70*circle_orbit_curcumference/circles, 
-			(rim_radius-hub_diameter/2)*0.9);
+        (rim_radius+hub_diameter/2)*0.9);
-
+    circle_diameter=(circle_diameter != undef)? circle_diameter : circle_default_diameter;
+    echo(str("cir_orb_dia: ", circle_orbit_diameter, ", cir_orb_circumf: ", circle_orbit_curcumference, ", default cir dia: ",circle_default_diameter, ", cir_dia:",circle_diameter));
     difference()
     {
         union ()
         {
             difference ()
             {
+                //start with a plane toothed disk gear
                 linear_extrude_flat_option(flat=flat, height=rim_thickness, convexity=10, twist=twist)
                 gear_shape (
                     number_of_teeth,
@@ -383,21 +404,78 @@ module gear (
                     half_thick_angle = half_thick_angle,
                     involute_facets=involute_facets);
 
-				if (flat == false && gear_thickness < rim_thickness)
+                //if we have a 0 hub thickness, then hub must be removed
+                if (hub_thickness == 0)
+                    translate ([0,0,-1])
+                    cylinder (r=rim_radius,h=rim_thickness+2);
+                //if the rim is thicker than the gear, carve out gear body
+                else if (rim_thickness>gear_thickness){
+                    //if not centered, carve out only the top
+                    if (centered_gear == false){
                         translate ([0,0,gear_thickness])
-					cylinder (r=rim_radius,h=rim_thickness-gear_thickness+1);
+                        cylinder (r=rim_radius,h=rim_thickness);
                     }
+                    else
+                        //carve out half from top and half from bottom
+                        union ()
+                        {
+                            translate ([0,0,(gear_thickness + rim_thickness)/2])
+                                cylinder (r=rim_radius,h=rim_thickness+1);
+                            translate ([0,0,-1 -(gear_thickness + rim_thickness)/2])
+                                cylinder (r=rim_radius,h=rim_thickness+1);
+                        }
+                
+                }
+            }
+            
+            //extend the gear body if gear_thickness > rim_thickness unless spoked, 
             if (gear_thickness > rim_thickness)
+            {
+                if (centered_gear == false)
+                {
                     linear_extrude_flat_option(flat=flat, height=gear_thickness)
                     circle (r=rim_radius);
-			if (flat == false && hub_thickness > gear_thickness)
-				translate ([0,0,gear_thickness])
-				linear_extrude_flat_option(flat=flat, height=hub_thickness-gear_thickness)
-				circle (r=hub_diameter/2);
                 }
+                else
+                {
+                    translate ([0,0,-(gear_thickness - rim_thickness)/2])
+                    linear_extrude_flat_option(flat=flat, height=gear_thickness)
+                    circle (r=rim_radius);
+                }
+                //if rim is thicker than body, body protrudes into rim
+            }
+            //add the hub
+            translate ([0,0,hub_base])
+            linear_extrude_flat_option(flat=flat, height=hub_thickness)
+                circle (r=hub_diameter/2);
+            
+            //add in spokes
+            if (spokes>0)
+            {          
+                for(i=[0:spokes-1])
+                    translate([0,0,rim_thickness/2])
+                    rotate([90,0,i*360/spokes])
+                    translate([0,0,spoke_radius])
+                    {
+                        if (spoke_square==true){
+                             resize([spoke_width,spoke_thickness,spoke_length])
+                            translate([0,0,.5])
+                            cube(1,center=true);
+                        }
+                        if (spoke_square==false){
+                            resize([spoke_width,spoke_thickness,spoke_length])
+                            cylinder(h=10,d=10);
+                        }
+                    }
+            }
+        }
+        
+        //remove the center bore
         translate ([0,0,-1])
         linear_extrude_flat_option(flat =flat, height=2+max(rim_thickness,hub_thickness,gear_thickness))
         circle (r=bore_diameter/2);
+        
+        //remove circles from gear body
         if (circles>0)
         {
             for(i=[0:circles-1])
@@ -423,10 +501,10 @@ module rack(
         echo("MCAD ERROR: gear module needs either a diametral_pitch or circular_pitch");
 
     //Convert diametrial pitch to our native circular pitch
-	circular_pitch = (circular_pitch!=false?circular_pitch:180/diametral_pitch);
+    circular_pitch = (circular_pitch!=false?circular_pitch:pi/diametral_pitch);
-	pitch = circular_pitch / 180 * PI;
+    pitch = circular_pitch;
 
-	addendum = circular_pitch / 180;
+    addendum = circular_pitch / pi;
     dedendum = addendum + clearance;
     pitch_slope = tan(pressure_angle);
 
@@ -566,23 +644,31 @@ function involute (base_radius, involute_angle) =
 
 module test_gears()
 {
+    $fs = 0.2;
+    $fa =1;
     translate([17,-15])
     {
         gear (number_of_teeth=17,
-			circular_pitch=500,
+            circular_pitch=500*pi/180,
-			circles=8);
+            spokes=6,
+            spoke_thickness=4,
+            gear_thickness=0,
+            rim_thickness=5,
+            hub_thickness=5,
+            hub_diameter=10,
+            circles=0);
 
         rotate ([0,0,360*4/17])
         translate ([39.088888,0,0])
         {
             gear (number_of_teeth=11,
-				circular_pitch=500,
+                circular_pitch=500*pi/180,
                 hub_diameter=0,
                 rim_width=65);
             translate ([0,0,8])
             {
                 gear (number_of_teeth=6,
-					circular_pitch=300,
+                    circular_pitch=300*pi/180,
                     hub_diameter=0,
                     rim_width=5,
                     rim_thickness=6,
@@ -590,7 +676,7 @@ module test_gears()
                 rotate ([0,0,360*5/6])
                 translate ([22.5,0,1])
                 gear (number_of_teeth=21,
-					circular_pitch=300,
+                    circular_pitch=300*pi/180,
                     bore_diameter=2,
                     hub_diameter=4,
                     rim_width=1,
@@ -604,22 +690,29 @@ module test_gears()
         translate ([-61.1111111,0,0])
         {
             gear (number_of_teeth=27,
-				circular_pitch=500,
+                circular_pitch=500*pi/180,
-				circles=5,
+                circles=6,
+                circle_diameter=12,
+                spokes=6,
+                gear_thickness=2,
+                hub_thickness=10,
+                centered_gear=true,
+                spoke_thickness=3,
                 hub_diameter=2*8.88888889);
 
             translate ([-37.5,0,0])
             rotate ([0,0,-90])
             rack (
-				circular_pitch=500
+                circular_pitch=500*pi/180
                  );
 
             translate ([0,0,10])
             {
                 gear (
                     number_of_teeth=14,
-					circular_pitch=200,
+                    circular_pitch=200*pi/180,
                     pressure_angle=5,
+                    twist=30,
                     clearance = 0.2,
                     gear_thickness = 10,
                     rim_thickness = 10,
@@ -628,16 +721,18 @@ module test_gears()
                     circles=0);
                 translate ([13.8888888,0,1])
                 gear (
-					number_of_teeth=11,
+                    number_of_teeth=10,
-					circular_pitch=200,
+                    circular_pitch=200*pi/180,
                     pressure_angle=5,
                     clearance = 0.2,
                     gear_thickness = 10,
-					rim_thickness = 10,
+                    rim_thickness = 8,
+                    twist=-30*8/10,
                     rim_width = 15,
-					hub_thickness = 20,
+                    hub_thickness = 10,
-					hub_diameter=2*7.222222,
+                    centered_hub=true,
-					bore_diameter=5,
+                    hub_diameter=7,
+                    bore_diameter=4,
                     circles=0);
             }
         }
@@ -645,7 +740,7 @@ module test_gears()
         rotate ([0,0,360*-5/17])
         translate ([44.444444444,0,0])
         gear (number_of_teeth=15,
-			circular_pitch=500,
+            circular_pitch=500*pi/180,
             hub_diameter=10,
             rim_width=5,
             rim_thickness=5,
@@ -656,7 +751,7 @@ module test_gears()
         rotate ([0,0,360*-1/17])
         translate ([30.5555555,0,-1])
         gear (number_of_teeth=5,
-			circular_pitch=500,
+            circular_pitch=500*pi/180,
             hub_diameter=0,
             rim_width=5,
             rim_thickness=10);
@@ -683,7 +778,7 @@ module test_double_helix_gear (
         pressure_angle=30;
 
         gear (number_of_teeth=teeth,
-			circular_pitch=700,
+            circular_pitch=700*pi/180,
             pressure_angle=pressure_angle,
             clearance = 0.2,
             gear_thickness = height/2*0.5,
@@ -696,7 +791,7 @@ module test_double_helix_gear (
             twist=twist/teeth);
         mirror([0,0,1])
         gear (number_of_teeth=teeth,
-			circular_pitch=700,
+            circular_pitch=700*pi/180,
             pressure_angle=pressure_angle,
             clearance = 0.2,
             gear_thickness = height/2,
@@ -721,7 +816,7 @@ module test_backlash ()
         rotate ([0,0,-360/teeth/4])
         gear (
             number_of_teeth = teeth,
-			circular_pitch=700,
+            circular_pitch=700*pi/180,
             gear_thickness = 12,
             rim_thickness = 15,
             rim_width = 5,
@@ -734,7 +829,7 @@ module test_backlash ()
         rotate ([0,0,360/teeth/4])
         gear (
             number_of_teeth = teeth,
-			circular_pitch=700,
+            circular_pitch=700*pi/180,
             gear_thickness = 12,
             rim_thickness = 15,
             rim_width = 5,
@@ -745,7 +840,8 @@ module test_backlash ()
             circles=8);
     }
 
-	color([0,0,128,0.5])
+    color([0,0,1,0.5])
     translate([0,0,-5])
     cylinder ($fn=20,r=backlash / 4,h=25);
 }
+