77 lines
2.8 KiB
Plaintext
77 lines
2.8 KiB
Plaintext
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// Spur Gear
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// A rotating machine part having cut teeth or, in the case of a cogwheel, inserted teeth (called cogs), which mesh with another toothed part to transmit torque. Geared devices can change the speed, torque, and direction of a power source. The two elements that define a gear are its circular shape and the teeth that are integrated into its outer edge, which are designed to fit into the teeth of another gear.
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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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// Define 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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// Define the constants of the keyway and the bore hole
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keywayWidth = 2
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keywayDepth = keywayWidth / 2
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holeDiam = 5
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holeRadius = holeDiam / 2
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startAngle = asin(keywayWidth / 2 / holeRadius)
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// Sketch the keyway and center hole
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holeWithKeyway = startSketchOn(XY)
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|> startProfile(at = [
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holeRadius * cos(startAngle),
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holeRadius * sin(startAngle)
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])
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|> xLine(length = keywayDepth)
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|> yLine(length = -keywayWidth)
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|> xLine(length = -keywayDepth)
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|> arc(angleStart = -1 * startAngle + 360, angleEnd = 180, radius = holeRadius)
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|> arc(angleStart = 180, angleEnd = startAngle, radius = holeRadius)
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|> close()
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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 the keyway sketch from the gear sketch
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|> subtract2d(tool = holeWithKeyway)
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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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spurGear(
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nTeeth = 21,
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module = 1.5,
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pressureAngle = 14,
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gearHeight = 6,
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)
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