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2 | 2 | // 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. |
3 | 3 |
|
4 | 4 | // Set units |
5 | | -@settings(defaultLengthUnit = in, kclVersion = 1.0) |
| 5 | +@settings(defaultLengthUnit = in) |
6 | 6 |
|
7 | | -// Define parameters |
8 | | -nTeeth = 21 |
9 | | -module = 0.5 |
10 | | -pitchDiameter = module * nTeeth |
11 | | -pressureAngle = 20 |
12 | | -addendum = module |
13 | | -deddendum = 1.25 * module |
14 | | -baseDiameter = pitchDiameter * cos(pressureAngle) |
15 | | -tipDiameter = pitchDiameter + 2 * module |
16 | | -gearHeight = 3 |
| 7 | +// Define a function to create a spur gear |
| 8 | +fn spurGear(nTeeth, module, pressureAngle, gearHeight) { |
| 9 | + // Define gear parameters |
| 10 | + pitchDiameter = module * nTeeth |
| 11 | + addendum = module |
| 12 | + deddendum = 1.25 * module |
| 13 | + baseDiameter = pitchDiameter * cos(pressureAngle) |
| 14 | + tipDiameter = pitchDiameter + 2 * module |
17 | 15 |
|
18 | | -// Interpolate points along the involute curve |
19 | | -cmo = 101 |
20 | | -rs = map( |
21 | | - [0..cmo], |
22 | | - f = fn(@i) { |
23 | | - return baseDiameter / 2 + i / cmo * (tipDiameter - baseDiameter) / 2 |
24 | | - }, |
25 | | -) |
26 | | - |
27 | | -// Calculate operating pressure angle |
28 | | -angles = map( |
29 | | - rs, |
30 | | - f = fn(@r) { |
31 | | - return units::toDegrees(acos(baseDiameter / 2 / r)) |
32 | | - }, |
33 | | -) |
| 16 | + // Define the constants of the keyway and the bore hole |
| 17 | + keywayWidth = 2 |
| 18 | + keywayDepth = keywayWidth / 2 |
| 19 | + holeDiam = 5 |
| 20 | + holeRadius = holeDiam / 2 |
| 21 | + startAngle = asin(keywayWidth / 2 / holeRadius) |
34 | 22 |
|
35 | | -// Calculate the involute function |
36 | | -invas = map( |
37 | | - angles, |
38 | | - f = fn(@a) { |
39 | | - return tan(a) - units::toRadians(a) |
40 | | - }, |
41 | | -) |
| 23 | + // Sketch the keyway and center hole |
| 24 | + holeWithKeyway = startSketchOn(XY) |
| 25 | + |> startProfile(at = [ |
| 26 | + holeRadius * cos(startAngle), |
| 27 | + holeRadius * sin(startAngle) |
| 28 | + ]) |
| 29 | + |> xLine(length = keywayDepth) |
| 30 | + |> yLine(length = -keywayWidth) |
| 31 | + |> xLine(length = -keywayDepth) |
| 32 | + |> arc(angleStart = -1 * startAngle + 360, angleEnd = 180, radius = holeRadius) |
| 33 | + |> arc(angleStart = 180, angleEnd = startAngle, radius = holeRadius) |
| 34 | + |> close() |
42 | 35 |
|
43 | | -// Map the involute curve |
44 | | -xs = map( |
45 | | - [0..cmo], |
46 | | - f = fn(@i) { |
47 | | - return rs[i] * cos(invas[i]: number(rad)) |
48 | | - }, |
49 | | -) |
50 | | - |
51 | | -ys = map( |
52 | | - [0..cmo], |
53 | | - f = fn(@i) { |
54 | | - return rs[i] * sin(invas[i]: number(rad)) |
55 | | - }, |
56 | | -) |
| 36 | + // Using the gear parameters, sketch an involute tooth spanning from the base diameter to the tip diameter |
| 37 | + gearSketch = startSketchOn(XY) |
| 38 | + |> startProfile(at = polar(angle = 0, length = baseDiameter / 2)) |
| 39 | + |> involuteCircular( |
| 40 | + startRadius = baseDiameter / 2, |
| 41 | + endRadius = tipDiameter / 2, |
| 42 | + angle = 0, |
| 43 | + tag = $seg01, |
| 44 | + ) |
| 45 | + |> line(endAbsolute = polar(angle = 160 / nTeeth, length = tipDiameter / 2)) |
| 46 | + |> involuteCircular( |
| 47 | + startRadius = baseDiameter / 2, |
| 48 | + endRadius = tipDiameter / 2, |
| 49 | + angle = -atan(segEndY(seg01) / segEndX(seg01)) - (180 / nTeeth), |
| 50 | + reverse = true, |
| 51 | + ) |
| 52 | + // Position the end line of the sketch at the start of the next tooth |
| 53 | + |> line(endAbsolute = polar(angle = 360 / nTeeth, length = baseDiameter / 2)) |
| 54 | + // Pattern the sketch about the center by the specified number of teeth, then close the sketch |
| 55 | + |> patternCircular2d( |
| 56 | + %, |
| 57 | + instances = nTeeth, |
| 58 | + center = [0, 0], |
| 59 | + arcDegrees = 360, |
| 60 | + rotateDuplicates = true, |
| 61 | + ) |
| 62 | + |> close() |
| 63 | + // Subtract the keyway sketch from the gear sketch |
| 64 | + |> subtract2d(tool = holeWithKeyway) |
| 65 | + // Extrude the gear to the specified height |
| 66 | + |> extrude(length = gearHeight) |
57 | 67 |
|
58 | | -// Extrude the gear body |
59 | | -body = startSketchOn(XY) |
60 | | - |> circle(center = [0, 0], radius = baseDiameter / 2) |
61 | | - |> extrude(length = gearHeight) |
62 | | - |
63 | | -toothAngle = 360 / nTeeth / 1.5 |
64 | | - |
65 | | -// Plot the involute curve |
66 | | -fn leftInvolute(@i, accum) { |
67 | | - j = 100 - i // iterate backwards |
68 | | - return line(accum, endAbsolute = [xs[j], ys[j]]) |
69 | | -} |
70 | | - |
71 | | -fn rightInvolute(@i, accum) { |
72 | | - x = rs[i] * cos(-toothAngle + units::toDegrees(atan(ys[i] / xs[i]))) |
73 | | - y = -rs[i] * sin(-toothAngle + units::toDegrees(atan(ys[i] / xs[i]))) |
74 | | - return line(accum, endAbsolute = [x, y]) |
| 68 | + return gearSketch |
75 | 69 | } |
76 | 70 |
|
77 | | -// Draw gear teeth |
78 | | -start = startSketchOn(XY) |
79 | | - |> startProfile(at = [xs[101], ys[101]]) |
80 | | -teeth = reduce([0..100], initial = start, f = leftInvolute) |
81 | | - |> arc(angleStart = 0, angleEnd = toothAngle, radius = baseDiameter / 2) |
82 | | - |> reduce([1..101], initial = %, f = rightInvolute) |
83 | | - |> close() |
84 | | - |> extrude(length = gearHeight) |
85 | | - |> patternCircular3d( |
86 | | - axis = [0, 0, 1], |
87 | | - center = [0, 0, 0], |
88 | | - instances = nTeeth, |
89 | | - arcDegrees = 360, |
90 | | - rotateDuplicates = true, |
91 | | - ) |
92 | | - |
93 | | -// Define the constants of the keyway and the bore hole |
94 | | -keywayWidth = 0.250 |
95 | | -keywayDepth = keywayWidth / 2 |
96 | | -holeDiam = 2 |
97 | | -holeRadius = 1 |
98 | | -startAngle = asin(keywayWidth / 2 / holeRadius) |
| 71 | +spurGear( |
| 72 | + nTeeth = 21, |
| 73 | + module = 1.5, |
| 74 | + pressureAngle = 14, |
| 75 | + gearHeight = 6, |
| 76 | +) |
99 | 77 |
|
100 | | -// Sketch the keyway and center hole and extrude |
101 | | -keyWay = startSketchOn(body, face = END) |
102 | | - |> startProfile(at = [ |
103 | | - holeRadius * cos(startAngle), |
104 | | - holeRadius * sin(startAngle) |
105 | | - ]) |
106 | | - |> xLine(length = keywayDepth) |
107 | | - |> yLine(length = -keywayWidth) |
108 | | - |> xLine(length = -keywayDepth) |
109 | | - |> arc(angleStart = -1 * units::toDegrees(startAngle) + 360, angleEnd = 180, radius = holeRadius) |
110 | | - |> arc(angleStart = 180, angleEnd = units::toDegrees(startAngle), radius = holeRadius) |
111 | | - |> close() |
112 | | - |> extrude(length = -gearHeight) |
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