848 lines
28 KiB
OpenSCAD
848 lines
28 KiB
OpenSCAD
// Parametric Involute Bevel and Spur Gears by GregFrost
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// It is licensed under the Creative Commons - GNU LGPL 2.1 license.
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// © 2010 by GregFrost, thingiverse.com/Amp
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// http://www.thingiverse.com/thing:3575 and http://www.thingiverse.com/thing:3752
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// Simple Test:
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//gear (circular_pitch=700,
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// gear_thickness = 12,
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// rim_thickness = 15,
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// hub_thickness = 17,
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// circles=8);
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//Complex Spur Gear Test:
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//test_gears ();
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// Meshing Double Helix:
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//test_meshing_double_helix ();
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module test_meshing_double_helix(){
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meshing_double_helix ();
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}
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// Demonstrate the backlash option for Spur gears.
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//test_backlash ();
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// Demonstrate how to make meshing bevel gears.
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//test_bevel_gear_pair();
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module test_bevel_gear_pair(){
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bevel_gear_pair ();
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}
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module test_bevel_gear(){bevel_gear();}
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//bevel_gear();
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pi=3.1415926535897932384626433832795;
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//==================================================
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// Bevel Gears:
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// Two gears with the same cone distance, circular pitch (measured at the cone distance)
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// and pressure angle will mesh.
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module bevel_gear_pair (
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gear1_teeth = 41,
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gear2_teeth = 7,
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axis_angle = 90,
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outside_circular_pitch=1000)
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{
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outside_pitch_radius1 = gear1_teeth * outside_circular_pitch / 360;
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outside_pitch_radius2 = gear2_teeth * outside_circular_pitch / 360;
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pitch_apex1=outside_pitch_radius2 * sin (axis_angle) +
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(outside_pitch_radius2 * cos (axis_angle) + outside_pitch_radius1) / tan (axis_angle);
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cone_distance = sqrt (pow (pitch_apex1, 2) + pow (outside_pitch_radius1, 2));
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pitch_apex2 = sqrt (pow (cone_distance, 2) - pow (outside_pitch_radius2, 2));
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echo ("cone_distance", cone_distance);
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pitch_angle1 = asin (outside_pitch_radius1 / cone_distance);
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pitch_angle2 = asin (outside_pitch_radius2 / cone_distance);
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echo ("pitch_angle1, pitch_angle2", pitch_angle1, pitch_angle2);
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echo ("pitch_angle1 + pitch_angle2", pitch_angle1 + pitch_angle2);
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rotate([0,0,90])
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translate ([0,0,pitch_apex1+20])
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{
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translate([0,0,-pitch_apex1])
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bevel_gear (
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number_of_teeth=gear1_teeth,
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cone_distance=cone_distance,
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pressure_angle=30,
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outside_circular_pitch=outside_circular_pitch);
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rotate([0,-(pitch_angle1+pitch_angle2),0])
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translate([0,0,-pitch_apex2])
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bevel_gear (
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number_of_teeth=gear2_teeth,
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cone_distance=cone_distance,
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pressure_angle=30,
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outside_circular_pitch=outside_circular_pitch);
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}
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}
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//Bevel Gear Finishing Options:
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bevel_gear_flat = 0;
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bevel_gear_back_cone = 1;
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module bevel_gear (
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number_of_teeth=11,
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cone_distance=100,
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face_width=20,
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outside_circular_pitch=1000,
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pressure_angle=30,
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clearance = 0.2,
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bore_diameter=5,
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gear_thickness = 15,
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backlash = 0,
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involute_facets=0,
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finish = -1)
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{
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echo ("bevel_gear",
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"teeth", number_of_teeth,
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"cone distance", cone_distance,
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face_width,
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outside_circular_pitch,
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pressure_angle,
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clearance,
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bore_diameter,
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involute_facets,
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finish);
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// Pitch diameter: Diameter of pitch circle at the fat end of the gear.
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outside_pitch_diameter = number_of_teeth * outside_circular_pitch / 180;
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outside_pitch_radius = outside_pitch_diameter / 2;
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// The height of the pitch apex.
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pitch_apex = sqrt (pow (cone_distance, 2) - pow (outside_pitch_radius, 2));
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pitch_angle = asin (outside_pitch_radius/cone_distance);
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echo ("Num Teeth:", number_of_teeth, " Pitch Angle:", pitch_angle);
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finish = (finish != -1) ? finish : (pitch_angle < 45) ? bevel_gear_flat : bevel_gear_back_cone;
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apex_to_apex=cone_distance / cos (pitch_angle);
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back_cone_radius = apex_to_apex * sin (pitch_angle);
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// Calculate and display the pitch angle. This is needed to determine the angle to mount two meshing cone gears.
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// Base Circle for forming the involute teeth shape.
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base_radius = back_cone_radius * cos (pressure_angle);
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// Diametrial pitch: Number of teeth per unit length.
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pitch_diametrial = number_of_teeth / outside_pitch_diameter;
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// Addendum: Radial distance from pitch circle to outside circle.
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addendum = 1 / pitch_diametrial;
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// Outer Circle
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outer_radius = back_cone_radius + addendum;
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// Dedendum: Radial distance from pitch circle to root diameter
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dedendum = addendum + clearance;
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dedendum_angle = atan (dedendum / cone_distance);
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root_angle = pitch_angle - dedendum_angle;
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root_cone_full_radius = tan (root_angle)*apex_to_apex;
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back_cone_full_radius=apex_to_apex / tan (pitch_angle);
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back_cone_end_radius =
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outside_pitch_radius -
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dedendum * cos (pitch_angle) -
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gear_thickness / tan (pitch_angle);
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back_cone_descent = dedendum * sin (pitch_angle) + gear_thickness;
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// Root diameter: Diameter of bottom of tooth spaces.
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root_radius = back_cone_radius - dedendum;
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half_tooth_thickness = outside_pitch_radius * sin (360 / (4 * number_of_teeth)) - backlash / 4;
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half_thick_angle = asin (half_tooth_thickness / back_cone_radius);
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face_cone_height = apex_to_apex-face_width / cos (pitch_angle);
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face_cone_full_radius = face_cone_height / tan (pitch_angle);
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face_cone_descent = dedendum * sin (pitch_angle);
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face_cone_end_radius =
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outside_pitch_radius -
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face_width / sin (pitch_angle) -
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face_cone_descent / tan (pitch_angle);
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// For the bevel_gear_flat finish option, calculate the height of a cube to select the portion of the gear that includes the full pitch face.
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bevel_gear_flat_height = pitch_apex - (cone_distance - face_width) * cos (pitch_angle);
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// translate([0,0,-pitch_apex])
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difference ()
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{
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intersection ()
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{
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union()
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{
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rotate (half_thick_angle)
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translate ([0,0,pitch_apex-apex_to_apex])
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cylinder ($fn=number_of_teeth*2, r1=root_cone_full_radius,r2=0,h=apex_to_apex);
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for (i = [1:number_of_teeth])
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// for (i = [1:1])
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{
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rotate ([0,0,i*360/number_of_teeth])
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{
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involute_bevel_gear_tooth (
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back_cone_radius = back_cone_radius,
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root_radius = root_radius,
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base_radius = base_radius,
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outer_radius = outer_radius,
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pitch_apex = pitch_apex,
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cone_distance = cone_distance,
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half_thick_angle = half_thick_angle,
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involute_facets = involute_facets);
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}
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}
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}
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if (finish == bevel_gear_back_cone)
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{
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translate ([0,0,-back_cone_descent])
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cylinder (
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$fn=number_of_teeth*2,
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r1=back_cone_end_radius,
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r2=back_cone_full_radius*2,
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h=apex_to_apex + back_cone_descent);
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}
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else
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{
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translate ([-1.5*outside_pitch_radius,-1.5*outside_pitch_radius,0])
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cube ([3*outside_pitch_radius,
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3*outside_pitch_radius,
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bevel_gear_flat_height]);
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}
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}
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if (finish == bevel_gear_back_cone)
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{
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translate ([0,0,-face_cone_descent])
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cylinder (
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r1=face_cone_end_radius,
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r2=face_cone_full_radius * 2,
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h=face_cone_height + face_cone_descent+pitch_apex);
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}
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translate ([0,0,pitch_apex - apex_to_apex])
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cylinder (r=bore_diameter/2,h=apex_to_apex);
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}
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}
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module involute_bevel_gear_tooth (
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back_cone_radius,
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root_radius,
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base_radius,
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outer_radius,
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pitch_apex,
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cone_distance,
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half_thick_angle,
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involute_facets)
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{
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// echo ("involute_bevel_gear_tooth",
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// back_cone_radius,
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// root_radius,
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// base_radius,
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// outer_radius,
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// pitch_apex,
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// cone_distance,
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// half_thick_angle);
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min_radius = max (base_radius*2,root_radius*2);
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pitch_point =
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involute (
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base_radius*2,
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involute_intersect_angle (base_radius*2, back_cone_radius*2));
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pitch_angle = atan2 (pitch_point[1], pitch_point[0]);
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centre_angle = pitch_angle + half_thick_angle;
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start_angle = involute_intersect_angle (base_radius*2, min_radius);
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stop_angle = involute_intersect_angle (base_radius*2, outer_radius*2);
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res=(involute_facets!=0)?involute_facets:($fn==0)?5:$fn/4;
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translate ([0,0,pitch_apex])
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rotate ([0,-atan(back_cone_radius/cone_distance),0])
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translate ([-back_cone_radius*2,0,-cone_distance*2])
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union ()
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{
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for (i=[1:res])
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{
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let (
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point1=
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involute (base_radius*2,start_angle+(stop_angle - start_angle)*(i-1)/res),
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point2=
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involute (base_radius*2,start_angle+(stop_angle - start_angle)*(i)/res))
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{
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let (
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side1_point1 = rotate_point (centre_angle, point1),
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side1_point2 = rotate_point (centre_angle, point2),
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side2_point1 = mirror_point (rotate_point (centre_angle, point1)),
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side2_point2 = mirror_point (rotate_point (centre_angle, point2)))
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{
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polyhedron (
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points=[
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[back_cone_radius*2+0.1,0,cone_distance*2],
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[side1_point1[0],side1_point1[1],0],
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[side1_point2[0],side1_point2[1],0],
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[side2_point2[0],side2_point2[1],0],
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[side2_point1[0],side2_point1[1],0],
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[0.1,0,0]],
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triangles=[[0,2,1],[0,3,2],[0,4,3],[0,1,5],[1,2,5],[2,3,5],[3,4,5],[0,5,4]]);
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}
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}
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}
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}
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}
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module gear (
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number_of_teeth=15,
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circular_pitch=undef, diametral_pitch=undef,
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pressure_angle=28,
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clearance = undef,
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gear_thickness=5,
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rim_thickness=undef,
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rim_width=undef,
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hub_thickness=undef,
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hub_diameter=undef,
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spokes=0,
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spoke_width=undef,
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spoke_thickness=undef,
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spoke_square=false,
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centered_gear=false,
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centered_hub=false,
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bore_diameter=undef,
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circles=0,
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circle_diameter=undef,
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backlash=0,
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twist=0,
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involute_facets=0,
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flat=false)
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{
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// Check for undefined circular pitch (happens when neither circular_pitch or diametral_pitch are specified)
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if (circular_pitch==undef)
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echo("MCAD ERROR: gear module needs either a diametral_pitch or circular_pitch");
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//Convert diametrial pitch to our native circular pitch
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circular_pitch = (circular_pitch!=undef?circular_pitch:pi/diametral_pitch);
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// Calculate default clearance if not specified
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clearance = (clearance!=undef?clearance:0.25 * circular_pitch / pi);
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// Pitch diameter: Diameter of pitch circle.
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pitch_diameter = number_of_teeth * circular_pitch / pi;
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pitch_radius = pitch_diameter/2;
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echo (str("Teeth: ", number_of_teeth, ", Pitch Radius: ", pitch_radius, ", Clearance: ", clearance));
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// Base Circle
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base_radius = pitch_radius*cos(pressure_angle);
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// Diametrial pitch: Number of teeth per unit length.
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pitch_diametrial = number_of_teeth / pitch_diameter;
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// Addendum: Radial distance from pitch circle to outside circle.
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addendum = 1/pitch_diametrial;
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//Outer Circle
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outer_radius = pitch_radius+addendum;
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// Dedendum: Radial distance from pitch circle to root diameter
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dedendum = addendum + clearance;
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// Root diameter: Diameter of bottom of tooth spaces.
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root_radius = pitch_radius-dedendum;
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backlash_angle = backlash / pitch_radius * 180 / pi;
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half_thick_angle = (360 / number_of_teeth - backlash_angle) / 4;
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// Variables controlling the rim.
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rim_thickness = (rim_thickness!=undef?(rim_thickness!=0?rim_thickness:gear_thickness):gear_thickness * 1.5);
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rim_width = (rim_width!=undef?rim_width:root_radius * .1);
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rim_radius = root_radius - rim_width;
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// Variables controlling the hub
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hub_thickness = (hub_thickness!=undef?(hub_thickness!=0?hub_thickness:gear_thickness):gear_thickness * 2);
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hub_diameter = (hub_diameter!=undef?hub_diameter:root_radius * .3);
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hub_base = (centered_hub == false)? 0 : rim_thickness/2 - hub_thickness/2;
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// Variables controlling the spokes
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spokes = spokes == undef? 0 : spokes;
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spoke_thickness = (spoke_thickness == undef)? rim_thickness : spoke_thickness;
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spoke_width = (spokes==0)? 1 : (spoke_width == undef)? 0.75 * pi * hub_diameter / spokes : spoke_width;
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//spoke_depth is depth spoke must penetrate into hub to ensure complete penetration
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spoke_depth = ((hub_diameter/2)^2-(spoke_width/2)^2)^0.5 +.01;
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//spoke length is length of spoke including the depth sunk into the hub
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spoke_length = spoke_depth+rim_radius-(hub_diameter/2.0);
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//spoke raius is the distance from gear center to base of the spoke(inside the hub)
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spoke_radius = (hub_diameter/2.0)-spoke_depth;
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//echo (str("spoke_width: ",spoke_width,", hub_diameter: ",hub_diameter, ", spoke_depth: ",spoke_depth));
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// Variables controlling the bore
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bore_diameter = bore_diameter!=undef?bore_diameter:root_radius * .1;
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// Variables controlling the circular holes in the gear.
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circle_orbit_diameter=hub_diameter/2+rim_radius;
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circle_orbit_curcumference=pi*circle_orbit_diameter;
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// Limit the circle size to 90% of the gear face.
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circle_default_diameter = min (
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0.70*circle_orbit_curcumference/circles,
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(rim_radius+hub_diameter/2)*0.9);
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circle_diameter=(circle_diameter != undef)? circle_diameter : circle_default_diameter;
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echo(str("cir_orb_dia: ", circle_orbit_diameter, ", cir_orb_circumf: ", circle_orbit_curcumference, ", default cir dia: ",circle_default_diameter, ", cir_dia:",circle_diameter));
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difference()
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{
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union ()
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{
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difference ()
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{
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//start with a plane toothed disk gear
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linear_extrude_flat_option(flat=flat, height=rim_thickness, convexity=10, twist=twist)
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gear_shape (
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number_of_teeth,
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pitch_radius = pitch_radius,
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root_radius = root_radius,
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base_radius = base_radius,
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outer_radius = outer_radius,
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half_thick_angle = half_thick_angle,
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involute_facets=involute_facets);
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//if we have a 0 hub thickness, then hub must be removed
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if (hub_thickness == 0)
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translate ([0,0,-1])
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cylinder (r=rim_radius,h=rim_thickness+2);
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//if the rim is thicker than the gear, carve out gear body
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else if (rim_thickness>gear_thickness){
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//if not centered, carve out only the top
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if (centered_gear == false){
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translate ([0,0,gear_thickness])
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cylinder (r=rim_radius,h=rim_thickness);
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}
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else
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//carve out half from top and half from bottom
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union ()
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{
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translate ([0,0,(gear_thickness + rim_thickness)/2])
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cylinder (r=rim_radius,h=rim_thickness+1);
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translate ([0,0,-1 -(gear_thickness + rim_thickness)/2])
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cylinder (r=rim_radius,h=rim_thickness+1);
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}
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}
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}
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//extend the gear body if gear_thickness > rim_thickness unless spoked,
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if (gear_thickness > rim_thickness)
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{
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if (centered_gear == false)
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{
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linear_extrude_flat_option(flat=flat, height=gear_thickness)
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circle (r=rim_radius);
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}
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else
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{
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translate ([0,0,-(gear_thickness - rim_thickness)/2])
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linear_extrude_flat_option(flat=flat, height=gear_thickness)
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circle (r=rim_radius);
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}
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//if rim is thicker than body, body protrudes into rim
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}
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//add the hub
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translate ([0,0,hub_base])
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linear_extrude_flat_option(flat=flat, height=hub_thickness)
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circle (r=hub_diameter/2);
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//add in spokes
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if (spokes>0)
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{
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for(i=[0:spokes-1])
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translate([0,0,rim_thickness/2])
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rotate([90,0,i*360/spokes])
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translate([0,0,spoke_radius])
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{
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if (spoke_square==true){
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resize([spoke_width,spoke_thickness,spoke_length])
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translate([0,0,.5])
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|
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])
|
|
rotate([0,0,i*360/circles])
|
|
translate([circle_orbit_diameter/2,0,-1])
|
|
linear_extrude_flat_option(flat =flat, height=max(gear_thickness,rim_thickness)+3)
|
|
circle(r=circle_diameter/2);
|
|
}
|
|
}
|
|
}
|
|
|
|
module rack(
|
|
number_of_teeth=15,
|
|
circular_pitch=false, diametral_pitch=false,
|
|
pressure_angle=28,
|
|
clearance=0.2,
|
|
rim_thickness=8,
|
|
rim_width=5,
|
|
flat=false)
|
|
{
|
|
|
|
if (circular_pitch==false && diametral_pitch==false)
|
|
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:pi/diametral_pitch);
|
|
pitch = circular_pitch;
|
|
|
|
addendum = circular_pitch / pi;
|
|
dedendum = addendum + clearance;
|
|
pitch_slope = tan(pressure_angle);
|
|
|
|
linear_extrude_flat_option(flat=flat, height=rim_thickness)
|
|
union()
|
|
{
|
|
translate([0,-dedendum-rim_width/2])
|
|
square([number_of_teeth*pitch, rim_width],center=true);
|
|
|
|
p1 = pitch / 4 + pitch_slope * dedendum;
|
|
p2 = pitch / 4 - pitch_slope * addendum;
|
|
for(i=[1:number_of_teeth])
|
|
translate([pitch*(i-number_of_teeth/2-0.5),0])
|
|
polygon(points=[
|
|
[-p1,-dedendum],
|
|
[p1,-dedendum],
|
|
[p2,addendum],
|
|
[-p2,addendum]
|
|
]);
|
|
}
|
|
}
|
|
|
|
module linear_extrude_flat_option(flat =false, height = 10, center = false, convexity = 2, twist = 0)
|
|
{
|
|
if(flat==false)
|
|
{
|
|
linear_extrude(height = height, center = center, convexity = convexity, twist= twist) children(0);
|
|
}
|
|
else
|
|
{
|
|
children(0);
|
|
}
|
|
|
|
}
|
|
|
|
module gear_shape (
|
|
number_of_teeth,
|
|
pitch_radius,
|
|
root_radius,
|
|
base_radius,
|
|
outer_radius,
|
|
half_thick_angle,
|
|
involute_facets)
|
|
{
|
|
union()
|
|
{
|
|
rotate (half_thick_angle) circle ($fn=number_of_teeth*2, r=root_radius);
|
|
|
|
for (i = [1:number_of_teeth])
|
|
{
|
|
rotate ([0,0,i*360/number_of_teeth])
|
|
{
|
|
involute_gear_tooth (
|
|
pitch_radius = pitch_radius,
|
|
root_radius = root_radius,
|
|
base_radius = base_radius,
|
|
outer_radius = outer_radius,
|
|
half_thick_angle = half_thick_angle,
|
|
involute_facets=involute_facets);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
module involute_gear_tooth (
|
|
pitch_radius,
|
|
root_radius,
|
|
base_radius,
|
|
outer_radius,
|
|
half_thick_angle,
|
|
involute_facets)
|
|
{
|
|
min_radius = max (base_radius,root_radius);
|
|
|
|
pitch_point = involute (base_radius, involute_intersect_angle (base_radius, pitch_radius));
|
|
pitch_angle = atan2 (pitch_point[1], pitch_point[0]);
|
|
centre_angle = pitch_angle + half_thick_angle;
|
|
|
|
start_angle = involute_intersect_angle (base_radius, min_radius);
|
|
stop_angle = involute_intersect_angle (base_radius, outer_radius);
|
|
|
|
res=(involute_facets!=0)?involute_facets:($fn==0)?5:$fn/4;
|
|
|
|
union ()
|
|
{
|
|
for (i=[1:res]) {
|
|
point1=involute (base_radius,start_angle+(stop_angle - start_angle)*(i-1)/res);
|
|
point2=involute (base_radius,start_angle+(stop_angle - start_angle)*i/res);
|
|
side1_point1=rotate_point (centre_angle, point1);
|
|
side1_point2=rotate_point (centre_angle, point2);
|
|
side2_point1=mirror_point (rotate_point (centre_angle, point1));
|
|
side2_point2=mirror_point (rotate_point (centre_angle, point2));
|
|
polygon (
|
|
points=[[0,0],side1_point1,side1_point2,side2_point2,side2_point1],
|
|
paths=[[0,1,2,3,4,0]]);
|
|
}
|
|
}
|
|
}
|
|
|
|
// Mathematical Functions
|
|
//===============
|
|
|
|
// Finds the angle of the involute about the base radius at the given distance (radius) from it's center.
|
|
//source: http://www.mathhelpforum.com/math-help/geometry/136011-circle-involute-solving-y-any-given-x.html
|
|
|
|
function involute_intersect_angle (base_radius, radius) = sqrt (pow (radius/base_radius, 2) - 1) * 180 / pi;
|
|
|
|
// Calculate the involute position for a given base radius and involute angle.
|
|
|
|
function rotated_involute (rotate, base_radius, involute_angle) =
|
|
[
|
|
cos (rotate) * involute (base_radius, involute_angle)[0] + sin (rotate) * involute (base_radius, involute_angle)[1],
|
|
cos (rotate) * involute (base_radius, involute_angle)[1] - sin (rotate) * involute (base_radius, involute_angle)[0]
|
|
];
|
|
|
|
function mirror_point (coord) =
|
|
[
|
|
coord[0],
|
|
-coord[1]
|
|
];
|
|
|
|
function rotate_point (rotate, coord) =
|
|
[
|
|
cos (rotate) * coord[0] + sin (rotate) * coord[1],
|
|
cos (rotate) * coord[1] - sin (rotate) * coord[0]
|
|
];
|
|
|
|
function involute (base_radius, involute_angle) =
|
|
[
|
|
base_radius*(cos (involute_angle) + involute_angle*pi/180*sin (involute_angle)),
|
|
base_radius*(sin (involute_angle) - involute_angle*pi/180*cos (involute_angle))
|
|
];
|
|
|
|
|
|
// Test Cases
|
|
//===============
|
|
|
|
module test_gears()
|
|
{
|
|
$fs = 0.2;
|
|
$fa =1;
|
|
translate([17,-15])
|
|
{
|
|
gear (number_of_teeth=17,
|
|
circular_pitch=500*pi/180,
|
|
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*pi/180,
|
|
hub_diameter=0,
|
|
rim_width=65);
|
|
translate ([0,0,8])
|
|
{
|
|
gear (number_of_teeth=6,
|
|
circular_pitch=300*pi/180,
|
|
hub_diameter=0,
|
|
rim_width=5,
|
|
rim_thickness=6,
|
|
pressure_angle=31);
|
|
rotate ([0,0,360*5/6])
|
|
translate ([22.5,0,1])
|
|
gear (number_of_teeth=21,
|
|
circular_pitch=300*pi/180,
|
|
bore_diameter=2,
|
|
hub_diameter=4,
|
|
rim_width=1,
|
|
hub_thickness=4,
|
|
rim_thickness=4,
|
|
gear_thickness=3,
|
|
pressure_angle=31);
|
|
}
|
|
}
|
|
|
|
translate ([-61.1111111,0,0])
|
|
{
|
|
gear (number_of_teeth=27,
|
|
circular_pitch=500*pi/180,
|
|
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*pi/180
|
|
);
|
|
|
|
translate ([0,0,10])
|
|
{
|
|
gear (
|
|
number_of_teeth=14,
|
|
circular_pitch=200*pi/180,
|
|
pressure_angle=5,
|
|
twist=30,
|
|
clearance = 0.2,
|
|
gear_thickness = 10,
|
|
rim_thickness = 10,
|
|
rim_width = 15,
|
|
bore_diameter=5,
|
|
circles=0);
|
|
translate ([13.8888888,0,1])
|
|
gear (
|
|
number_of_teeth=10,
|
|
circular_pitch=200*pi/180,
|
|
pressure_angle=5,
|
|
clearance = 0.2,
|
|
gear_thickness = 10,
|
|
rim_thickness = 8,
|
|
twist=-30*8/10,
|
|
rim_width = 15,
|
|
hub_thickness = 10,
|
|
centered_hub=true,
|
|
hub_diameter=7,
|
|
bore_diameter=4,
|
|
circles=0);
|
|
}
|
|
}
|
|
|
|
rotate ([0,0,360*-5/17])
|
|
translate ([44.444444444,0,0])
|
|
gear (number_of_teeth=15,
|
|
circular_pitch=500*pi/180,
|
|
hub_diameter=10,
|
|
rim_width=5,
|
|
rim_thickness=5,
|
|
gear_thickness=4,
|
|
hub_thickness=6,
|
|
circles=9);
|
|
|
|
rotate ([0,0,360*-1/17])
|
|
translate ([30.5555555,0,-1])
|
|
gear (number_of_teeth=5,
|
|
circular_pitch=500*pi/180,
|
|
hub_diameter=0,
|
|
rim_width=5,
|
|
rim_thickness=10);
|
|
}
|
|
}
|
|
|
|
module meshing_double_helix ()
|
|
{
|
|
test_double_helix_gear ();
|
|
|
|
mirror ([0,1,0])
|
|
translate ([58.33333333,0,0])
|
|
test_double_helix_gear (teeth=13,circles=6);
|
|
}
|
|
|
|
module test_double_helix_gear (
|
|
teeth=17,
|
|
circles=8)
|
|
{
|
|
//double helical gear
|
|
{
|
|
twist=200;
|
|
height=20;
|
|
pressure_angle=30;
|
|
|
|
gear (number_of_teeth=teeth,
|
|
circular_pitch=700*pi/180,
|
|
pressure_angle=pressure_angle,
|
|
clearance = 0.2,
|
|
gear_thickness = height/2*0.5,
|
|
rim_thickness = height/2,
|
|
rim_width = 5,
|
|
hub_thickness = height/2*1.2,
|
|
hub_diameter=15,
|
|
bore_diameter=5,
|
|
circles=circles,
|
|
twist=twist/teeth);
|
|
mirror([0,0,1])
|
|
gear (number_of_teeth=teeth,
|
|
circular_pitch=700*pi/180,
|
|
pressure_angle=pressure_angle,
|
|
clearance = 0.2,
|
|
gear_thickness = height/2,
|
|
rim_thickness = height/2,
|
|
rim_width = 5,
|
|
hub_thickness = height/2,
|
|
hub_diameter=15,
|
|
bore_diameter=5,
|
|
circles=circles,
|
|
twist=twist/teeth);
|
|
}
|
|
}
|
|
|
|
module test_backlash ()
|
|
{
|
|
backlash = 2;
|
|
teeth = 15;
|
|
|
|
translate ([-29.166666,0,0])
|
|
{
|
|
translate ([58.3333333,0,0])
|
|
rotate ([0,0,-360/teeth/4])
|
|
gear (
|
|
number_of_teeth = teeth,
|
|
circular_pitch=700*pi/180,
|
|
gear_thickness = 12,
|
|
rim_thickness = 15,
|
|
rim_width = 5,
|
|
hub_thickness = 17,
|
|
hub_diameter=15,
|
|
bore_diameter=5,
|
|
backlash = 2,
|
|
circles=8);
|
|
|
|
rotate ([0,0,360/teeth/4])
|
|
gear (
|
|
number_of_teeth = teeth,
|
|
circular_pitch=700*pi/180,
|
|
gear_thickness = 12,
|
|
rim_thickness = 15,
|
|
rim_width = 5,
|
|
hub_thickness = 17,
|
|
hub_diameter=15,
|
|
bore_diameter=5,
|
|
backlash = 2,
|
|
circles=8);
|
|
}
|
|
|
|
color([0,0,1,0.5])
|
|
translate([0,0,-5])
|
|
cylinder ($fn=20,r=backlash / 4,h=25);
|
|
}
|
|
|