3D models for gears

3d_models/gears.scad

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+// OpenSCAD Herringbone Wade's Gears Script
+// (c) 2011, Christopher "ScribbleJ" Jansen
+//
+// Thanks to Greg Frost for his great "Involute Gears" script.
+//
+// Licensed under the BSD license.
+include <MCAD/involute_gears.scad> 
+
+
+// WHAT TO GENERATE?
+//generate = 0;    // GENERATE BOTH GEARS FOR VIEWING
+generate = 0;    // GENERATE STEPPER GEAR FOR PRINTING
+// generate = 2;    // GENERATE DRIVE GEAR FOR PRINTING
+
+// OPTIONS COMMON TO BOTH GEARS:
+distance_between_axels = 60;
+gear_h = 10;
+gear_shaft_h = 6;
+
+
+// GEAR1 (SMALLER GEAR, STEPPER GEAR) OPTIONS:
+// It's helpful to choose prime numbers for the gear teeth.
+gear1_teeth = 13;
+gear1_shaft_d = 5.5;  			// diameter of motor shaft
+gear1_shaft_r  = gear1_shaft_d/2;	
+// gear1 shaft assumed to fill entire gear.
+// gear1 attaches by means of a captive nut and bolt (or actual setscrew)
+gear1_setscrew_offset = 5;			// Distance from motor on motor shaft.
+gear1_setscrew_d         = 3.5;		
+gear1_setscrew_r          = gear1_setscrew_d/2;
+gear1_captive_nut_d = 6.2;
+gear1_captive_nut_r  = gear1_captive_nut_d/2;
+gear1_captive_nut_h = 3;
+
+
+// GEAR2 (LARGER GEAR, DRIVE SHAFT GEAR) OPTIONS:
+gear2_teeth = 51;
+gear2_shaft_d = 8;
+gear2_shaft_r  = gear2_shaft_d/2;
+// gear2 has settable outer shaft diameter.
+gear2_shaft_outer_d = 18;
+gear2_shaft_outer_r  = gear2_shaft_outer_d/2;
+
+// gear2 has a hex bolt set in it, is either a hobbed bolt or has the nifty hobbed gear from MBI on it.
+gear2_bolt_hex_d       = 15;
+gear2_bolt_hex_r        = gear2_bolt_hex_d/2;
+// gear2_bolt_sink: How far down the gear shaft the bolt head sits; measured as distance from drive end of gear.
+gear2_bolt_sink          = 3;		
+// gear2's shaft is a bridge above the hex bolt shaft; this creates 1/3bridge_helper_h sized steps at top of shaft to help bridging.  (so bridge_helper_h/3 should be > layer height to have any effect)
+bridge_helper_h=3;
+
+gear2_rim_margin = 0;
+gear2_cut_circles  = 5;
+
+// gear2 setscrew option; not likely needed.
+gear2_setscrew_offset = 0;
+gear2_setscrew_d         = 0;
+gear2_setscrew_r          = gear2_setscrew_d/2;
+// captive nut for the setscrew
+gear2_captive_nut_d = 0;
+gear2_captive_nut_r  = gear2_captive_nut_d/2;
+gear2_captive_nut_h = 0;
+
+
+// Tolerances for geometry connections.
+AT=0.02;
+ST=AT*2;
+TT=AT/2;
+
+
+module bridge_helper()
+{
+	difference()
+	{
+		translate([0,0,-bridge_helper_h/2])
+		cylinder(r=gear2_bolt_hex_r+TT, h=bridge_helper_h+TT,$fn=6,center=true);
+		translate([0,0,-bridge_helper_h/2])
+		cube([gear2_bolt_hex_d+ST, gear2_shaft_d, bridge_helper_h+AT], center=true);
+	}
+}
+
+
+
+module gearsbyteethanddistance(t1=13,t2=51, d=60, teethtwist=1, which=1)
+{
+	cp = 360*d/(t1+t2);
+
+	g1twist = 360 * teethtwist / t1;
+	g2twist = 360 * teethtwist / t2;
+
+	g1p_d  =  t1 * cp / 180;
+	g2p_d  =  t2 * cp / 180;
+	g1p_r   = g1p_d/2;
+	g2p_r   = g2p_d/2;
+
+	echo(str("Your small ", t1, "-toothed gear will be ", g1p_d, "mm across (plus 1 gear tooth size) (PR=", g1p_r,")"));
+	echo(str("Your large ", t2, "-toothed gear will be ", g2p_d, "mm across (plus 1 gear tooth size) (PR=", g2p_r,")"));
+	echo(str("Your minimum drive bolt length (to end of gear) is: ", gear2_bolt_sink+bridge_helper_h, "mm and your max is: ", gear_h+gear_shaft_h, "mm."));
+	echo(str("Your gear mount axles should be ", d,"mm (", g1p_r+g2p_r,"mm calculated) from each other."));
+	if(which == 1)
+	{
+		// GEAR 1
+		difference()
+		{
+		union()
+		{
+			translate([0,0,(gear_h/2) - TT])
+				gear(	twist = g1twist, 
+					number_of_teeth=t1, 
+					circular_pitch=cp, 
+					gear_thickness = gear_shaft_h + (gear_h/2)+AT, 
+					rim_thickness = (gear_h/2)+AT, 
+					rim_width = 0,
+					hub_thickness = (gear_h/2)+AT, 
+					hub_width = 0,
+					bore_diameter=0); 
+	
+			translate([0,0,(gear_h/2) + AT])
+			rotate([180,0,0]) 
+				gear(	twist = -g1twist, 
+					number_of_teeth=t1, 
+					circular_pitch=cp, 
+					gear_thickness = (gear_h/2)+AT, 
+					rim_thickness = (gear_h/2)+AT, 
+					hub_thickness = (gear_h/2)+AT, 
+					bore_diameter=0); 
+		}
+			//DIFFERENCE:
+			//shafthole
+			translate([0,0,-TT]) 
+				cylinder(r=gear1_shaft_r, h=gear_h+gear_shaft_h+ST);
+
+			//setscrew shaft
+			translate([0,0,gear_h+gear_shaft_h-gear1_setscrew_offset])
+				rotate([0,90,0])
+				cylinder(r=gear1_setscrew_r, h=g1p_r);
+
+			//setscrew captive nut
+			translate([(g1p_r)/2, 0, gear_h+gear_shaft_h-gear1_captive_nut_r-gear1_setscrew_offset]) 
+				translate([0,0,(gear1_captive_nut_r+gear1_setscrew_offset)/2])
+					#cube([gear1_captive_nut_h, gear1_captive_nut_d, gear1_captive_nut_r+gear1_setscrew_offset+ST],center=true);
+			
+		
+		}
+	}
+	else
+	{
+		// GEAR 2
+		difference()
+		{
+		union()
+		{
+			translate([0,0,(gear_h/2) - TT])
+				gear(	twist = -g2twist, 
+					number_of_teeth=t2, 
+					circular_pitch=cp, 
+					gear_thickness = /* gear_shaft_h + */ (gear_h/2)+AT, 
+					rim_thickness = (gear_h/2)+AT, 
+					rim_width = gear2_rim_margin,
+					hub_diameter = gear2_shaft_outer_d,
+					hub_thickness = (gear_h/2)+AT, 
+					bore_diameter=0,
+					circles = gear2_cut_circles); 
+	
+			translate([0,0,(gear_h/2) + AT])
+			rotate([180,0,0]) 
+				gear(	twist = g2twist, 
+					number_of_teeth=t2, 
+					circular_pitch=cp, 
+					gear_thickness = (gear_h/2)+AT, 
+					rim_thickness = (gear_h/2)+AT, 
+					rim_width = gear2_rim_margin,
+					hub_diameter = gear2_shaft_outer_d,
+					hub_thickness = (gear_h/2)+AT, 
+					bore_diameter=0,
+					circles = gear2_cut_circles); 
+		}
+			//DIFFERENCE:
+			//shafthole
+			//translate([0,0,-TT]) 
+				//cylinder(r=gear2_shaft_r, h=gear_h+gear_shaft_h+ST);
+
+			//setscrew shaft
+			//translate([0,0,gear_h+gear_shaft_h-gear2_setscrew_offset])
+			//	rotate([0,90,0])
+			//	cylinder(r=gear2_setscrew_r, h=gear2_shaft_outer_d);
+
+			//setscrew captive nut
+			translate([(gear2_shaft_outer_d)/2, 0, gear_h+gear_shaft_h-gear2_captive_nut_r-gear2_setscrew_offset]) 
+				translate([0,0,(gear2_captive_nut_r+gear2_setscrew_offset)/2])
+					#cube([gear2_captive_nut_h, gear2_captive_nut_d, gear2_captive_nut_r+gear2_setscrew_offset+ST],center=true);
+
+			//trim shaft
+			//difference()
+			//{
+			//	translate([0,0,gear_h+AT])	cylinder(h=gear_shaft_h+ST, r=g2p_r);
+			//	translate([0,0,gear_h])	cylinder(h=gear_shaft_h, r=gear2_shaft_outer_r);
+			//}
+
+			//hex bolt shaft
+			translate([0,0,-TT]) cylinder(r=gear2_bolt_hex_r, h=gear_h+gear_shaft_h-gear2_bolt_sink+AT,$fn=6);
+
+		}
+
+		// hex bolt shaft bridge aid.
+		//translate([0,0,gear_h+gear_shaft_h-gear2_bolt_sink])
+		//	bridge_helper();
+		//translate([0,0,gear_h+gear_shaft_h-gear2_bolt_sink+bridge_helper_h/3])
+		//	rotate([0,0,60]) bridge_helper();
+		//translate([0,0,gear_h+gear_shaft_h-gear2_bolt_sink+((bridge_helper_h/3)*2)])
+		//	rotate([0,0,-60]) bridge_helper();
+	
+	}
+	
+}
+
+
+t1 = gear1_teeth;
+t2 = gear2_teeth;
+cp = 360*distance_between_axels/(t1+t2);
+g1p_d  =  t1 * cp / 180;
+g2p_d  =  t2 * cp / 180;
+g1p_r   = g1p_d/2;
+g2p_r   = g2p_d/2;
+
+if(generate == 1)
+{
+	gearsbyteethanddistance(t1 = gear1_teeth, t2=gear2_teeth, d=distance_between_axels, which=1);
+}
+else if(generate == 2)
+{
+	gearsbyteethanddistance(t1 = gear1_teeth, t2=gear2_teeth, d=distance_between_axels, which=2);
+}
+else
+{
+
+	translate([-g1p_r,0,0]) rotate([0,0,($t*360/gear1_teeth)]) gearsbyteethanddistance(t1 = gear1_teeth, t2=gear2_teeth, d=distance_between_axels, which=1);
+	translate([g2p_r,0,0])  rotate([0,0,($t*360/gear2_teeth)*-1]) gearsbyteethanddistance(t1 = gear1_teeth, t2=gear2_teeth, d=distance_between_axels, which=2);
+}
+
+