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gears.scad cleanup + examples

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This commit is contained in:
theOtherRob 2010-06-11 16:07:22 -04:00
parent 32b7d6b65f
commit 4129da763e
1 changed files with 41 additions and 39 deletions
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78
gears.scad
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@ -1,26 +1,6 @@
//test //test_involute_curve();
// gear(number_of_teeth=11,diametral_pitch=17); test_gears();
translate([(51+17)*200/360+1.15,0]) rotate(-0.02) demo_3d_gears();
gear(number_of_teeth=51,circular_pitch=200);
gear(number_of_teeth=17,circular_pitch=200);
translate([-50,0]) gear(number_of_teeth=17,diametral_pitch=2);
//test();
module test()
{
for (i=[0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15])
{
//echo(polar_to_cartesian([involute_intersect_angle( 0.1,i) , i ]));
translate(polar_to_cartesian([involute_intersect_angle( 0.1,i) , i ])) circle($fn=15, r=0.5);
//translate( involute_intersection_point(0.1,i,0) ) circle($fn=15, r=0.5);
}
}
// circular_pitch = pitch_diameter*180/ number_of_teeth;
// Geometry Sources: // Geometry Sources:
// http://www.cartertools.com/involute.html // http://www.cartertools.com/involute.html
@ -31,10 +11,10 @@ for (i=[0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15])
// Clearance: Radial distance between top of tooth on one gear to bottom of gap on another. // Clearance: Radial distance between top of tooth on one gear to bottom of gap on another.
module gear(number_of_teeth, module gear(number_of_teeth,
circular_pitch=false, diametrial_pitch=false, circular_pitch=false, diametral_pitch=false,
pressure_angle=20, clearance = 0) pressure_angle=20, clearance = 0)
{ {
if (circular_pitch==false && diametrical_pitch==false) echo("MCAD ERROR: gear module needs either a diametrical_pitch or circular_pitch"); 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 //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:180/diametral_pitch);
@ -65,7 +45,6 @@ module gear(number_of_teeth,
root_diameter = root_radius * 2; root_diameter = root_radius * 2;
half_thick_angle = 360 / (4 * number_of_teeth); half_thick_angle = 360 / (4 * number_of_teeth);
echo(half_thick_angle);
union() union()
{ {
@ -100,11 +79,6 @@ module involute_gear_tooth(
outer_to_base_angle = involute_intersect_angle( base_radius, outer_radius ); outer_to_base_angle = involute_intersect_angle( base_radius, outer_radius );
//echo(base_radius);
//echo(outer_radius);
//echo(outer_to_base_angle);
echo(acos(base_radius/pitch_radius));
base1 = 0 - pitch_to_base_angle - half_thick_angle; base1 = 0 - pitch_to_base_angle - half_thick_angle;
pitch1 = 0 - half_thick_angle; pitch1 = 0 - half_thick_angle;
outer1 = outer_to_base_angle - pitch_to_base_angle - half_thick_angle; outer1 = outer_to_base_angle - pitch_to_base_angle - half_thick_angle;
@ -130,7 +104,7 @@ module involute_gear_tooth(
if (root_radius > base_radius) if (root_radius > base_radius)
{ {
echo("true"); //echo("true");
polygon( points = [ polygon( points = [
r1_t,p1,o1,o2,p2,r2_t r1_t,p1,o1,o2,p2,r2_t
], convexity = 3); ], convexity = 3);
@ -144,7 +118,8 @@ module involute_gear_tooth(
} }
// Mathematical Functions
//===============
// Finds the angle of the involute about the base radius at the given distance (radius) from it's center. // 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 //source: http://www.mathhelpforum.com/math-help/geometry/136011-circle-involute-solving-y-any-given-x.html
@ -161,11 +136,38 @@ function polar_to_cartesian(polar) = [
]; ];
// == LEGACY == // Test Cases
// Finds the intersection of the involute about the base radius with a cricle of the given radius in cartesian coordinates [x,y]. //===============
//function involute_intersection_point(base_radius, radius, zero_angle) = polar_to_cartesian([ involute_intersect_angle(base_radius, radius)-zero_angle , radius ]); module test_gears()
{
gear(number_of_teeth=51,circular_pitch=200);
translate([0, 50])gear(number_of_teeth=17,circular_pitch=200);
translate([-50,0]) gear(number_of_teeth=17,diametral_pitch=1);
}
//function rotation_matrix(degrees) = [ [cos(degrees), -sin(degrees)] , [sin(degrees), cos(degrees)] ]; module demo_3d_gears()
{
//double helical gear
// (helics don't line up perfectly - for display purposes only ;)
translate([50,0])
{
linear_extrude(height = 10, center = true, convexity = 10, twist = -45)
gear(number_of_teeth=17,diametral_pitch=1);
translate([0,0,10]) linear_extrude(height = 10, center = true, convexity = 10, twist = 45)
gear(number_of_teeth=17,diametral_pitch=1);
}
//function involute_intersect_angle(base_radius, radius) = sqrt( pow(radius,2) - pow(base_radius,2) ) / base_radius - acos(base_radius / radius); //spur gear
translate([0,-50]) linear_extrude(height = 10, center = true, convexity = 10, twist = 0)
gear(number_of_teeth=17,diametral_pitch=1);
}
module test_involute_curve()
{
for (i=[0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15])
{
translate(polar_to_cartesian([involute_intersect_angle( 0.1,i) , i ])) circle($fn=15, r=0.5);
}
}