71 lines
2.2 KiB
Plaintext
71 lines
2.2 KiB
Plaintext
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// Spur Reduction Gearset
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// A pair of spur gears meshed together, with an equal module and different number of teeth
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// Set units
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@settings(defaultLengthUnit = mm)
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// Define a function to create a spur gear
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fn spurGear(nTeeth, module, pressureAngle, gearHeight) {
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// Calculate gear parameters
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pitchDiameter = module * nTeeth
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addendum = module
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deddendum = 1.25 * module
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baseDiameter = pitchDiameter * cos(pressureAngle)
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tipDiameter = pitchDiameter + 2 * module
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// Using the gear parameters, sketch an involute tooth spanning from the base diameter to the tip diameter
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gearSketch = startSketchOn(XY)
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|> startProfile(at = polar(angle = 0, length = baseDiameter / 2))
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|> involuteCircular(
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startRadius = baseDiameter / 2,
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endRadius = tipDiameter / 2,
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angle = 0,
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tag = $seg01,
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)
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|> line(endAbsolute = polar(angle = 160 / nTeeth, length = tipDiameter / 2))
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|> involuteCircular(
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startRadius = baseDiameter / 2,
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endRadius = tipDiameter / 2,
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angle = -atan(segEndY(seg01) / segEndX(seg01)) - (180 / nTeeth),
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reverse = true,
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)
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// Position the end line of the sketch at the start of the next tooth
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|> line(endAbsolute = polar(angle = 360 / nTeeth, length = baseDiameter / 2))
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// Pattern the sketch about the center by the specified number of teeth, then close the sketch
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|> patternCircular2d(
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%,
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instances = nTeeth,
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center = [0, 0],
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arcDegrees = 360,
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rotateDuplicates = true,
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)
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|> close()
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// Subtract a 10mm diameter center hole from the gear
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|> subtract2d(tool = circle(center = [0, 0], radius = 5))
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// Extrude the gear to the specified height
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|> extrude(length = gearHeight)
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return gearSketch
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}
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// Model a small gear
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spurGear(
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nTeeth = 17,
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module = 1.5,
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pressureAngle = 14,
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gearHeight = 9,
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)
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// Model a larger gear with the same module
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spurGear(
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nTeeth = 51,
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module = 1.5,
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pressureAngle = 14,
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gearHeight = 7,
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)
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// Translate the larger gear by the combined pitch radius of both gears, plus a small gap
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|> translate(x = (51 + 17) / 2 * 1.5 + 1.3)
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// Rotate the gear so that the teeth mesh but do not intersect
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|> rotate(yaw = 3)
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