gears

thingiverse

function main(params) { var dist = (params.numTeeth*params.circularPitch/8.28) +(params.numTeeth2*params.circularPitch2/8.28); var gear = Gear(params).translate([dist,dist,0]); params.numTeeth = numTeeth; params.circularPitch = circularPitch; params.pressureAngle = pressureAngle; params.clearance = clearance; params.thickness = thickness; function involuteGear(numTeeth, circularPitch, pressureAngle, clearance, thickness) { var addendum = circularPitch / Math.PI; var dedendum = addendum + clearance; var pitchRadius = numTeeth * circularPitch / (2 * Math.PI); var baseRadius = pitchRadius * Math.cos(Math.PI * pressureAngle / 180); var outerRadius = pitchRadius + addendum; var rootRadius = pitchRadius - dedendum; var maxtanlength = Math.sqrt(outerRadius*outerRadius - baseRadius*baseRadius); var maxangle = maxtanlength / baseRadius; var tl_at_pitchcircle = Math.sqrt(pitchRadius*pitchRadius - baseRadius*baseRadius); var angle_at_pitchcircle = tl_at_pitchcircle / baseRadius; var diffangle = angle_at_pitchcircle - Math.atan(angle_at_pitchcircle); var angularToothWidthAtBase = Math.PI / numTeeth + 2*diffangle; var resolution = 5; var points = [new CSG.Vector2D(0,0)]; for(var i = 0; i <= resolution; i++) { var angle = maxangle * i / resolution; var tanlength = angle * baseRadius; var radvector = CSG.Vector2D.fromAngle(angle); var tanvector = radvector.normal(); var p = radvector.times(baseRadius).plus(tanvector.times(tanlength)); points[i+1] = p; radvector = CSG.Vector2D.fromAngle(angularToothWidthAtBase - angle); tanvector = radvector.normal().negated(); p = radvector.times(baseRadius).plus(tanvector.times(tanlength)); points[2 * resolution + 2 - i] = p; } var tooth3d = new CSG.Polygon2D(points).extrude({offset: [0, 0, thickness]}); var allteeth = new CSG(); for(var i = 0; i < numTeeth; i++) { var angle = i*360/numTeeth; var rotatedtooth = tooth3d.rotateZ(angle); allteeth = allteeth.unionForNonIntersecting(rotatedtooth); } points = []; var toothAngle = 2 * Math.PI / numTeeth; var toothCenterAngle = 0.5 * angularToothWidthAtBase; for(var i = 0; i < numTeeth; i++) { var angle = toothCenterAngle + i * toothAngle; var p = CSG.Vector2D.fromAngle(angle).times(rootRadius); points.push(p); } var rootcircle = new CSG.Polygon2D(points).extrude({offset: [0, 0, thickness]}); var result = rootcircle.union(allteeth); return result; } function Gear(params) { if(arguments.length < 3) pressureAngle = 20; if(arguments.length < 4) clearance = 0; if(arguments.length < 5) thickness = 1; var addendum = circularPitch / Math.PI; var dedendum = addendum + clearance; var pitchRadius = numTeeth * circularPitch / (2 * Math.PI); var baseRadius = pitchRadius * Math.cos(Math.PI * pressureAngle / 180); var outerRadius = pitchRadius + addendum; var rootRadius = pitchRadius - dedendum; var maxtanlength = Math.sqrt(outerRadius*outerRadius - baseRadius*baseRadius); var maxangle = maxtanlength / baseRadius; var tl_at_pitchcircle = Math.sqrt(pitchRadius*pitchRadius - baseRadius*baseRadius); var angle_at_pitchcircle = tl_at_pitchcircle / baseRadius; var diffangle = angle_at_pitchcircle - Math.atan(angle_at_pitchcircle); var angularToothWidthAtBase = Math.PI / numTeeth + 2*diffangle; var resolution = 5; var points = [new CSG.Vector2D(0,0)]; for(var i = 0; i <= resolution; i++) { var angle = maxangle * i / resolution; var tanlength = angle * baseRadius; var radvector = CSG.Vector2D.fromAngle(angle); var tanvector = radvector.normal(); var p = radvector.times(baseRadius).plus(tanvector.times(tanlength)); points[i+1] = p; radvector = CSG.Vector2D.fromAngle(angularToothWidthAtBase - angle); tanvector = radvector.normal().negated(); p = radvector.times(baseRadius).plus(tanvector.times(tanlength)); points[2 * resolution + 2 - i] = p; } var tooth3d = new CSG.Polygon2D(points).extrude({offset: [0, 0, thickness]}); var allteeth = new CSG(); for(var i = 0; i < numTeeth; i++) { var angle = i*360/numTeeth; var rotatedtooth = tooth3d.rotateZ(angle); allteeth = allteeth.unionForNonIntersecting(rotatedtooth); } points = []; var toothAngle = 2 * Math.PI / numTeeth; var toothCenterAngle = 0.5 * angularToothWidthAtBase; for(var i = 0; i < numTeeth; i++) { var angle = toothCenterAngle + i * toothAngle; var p = CSG.Vector2D.fromAngle(angle).times(rootRadius); points.push(p); } var rootcircle = new CSG.Polygon2D(points).extrude({offset: [0, 0, thickness]}); var result = rootcircle.union(allteeth); return result; } }