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ring gear fixes
This commit is contained in:
Adrian Mariano
parent
437acbd7ea
commit
c5ce4e7d50
1 changed files with 215 additions and 40 deletions
255
gears.scad
255
gears.scad
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@ -267,8 +267,94 @@ function _inherit_gear_thickness(thickness) =
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// right and another that slopes to the left. Herringbone gears also have the advantage of being self-aligning.
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// Figure(3D,Med,NoAxes,VPT=[3.5641,-7.03148,4.86523],VPR=[62.7,0,29.2],VPD=263.285): A herringbone gear
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// spur_gear(mod=5, teeth=16, pressure_angle=20, thickness=35, helical=-20, herringbone=true, shaft_diam=15);
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// Subsection: Ring Gears (Internal Gears)
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// A ring gear (or internal gear) is a gear where the teeth are on the inside of a circle. Such gears must be mated
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// to a regular (external) gear, which rotates around the inside.
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// Figure(2D,Med,NoAxes,VPT =[0.491171,1.07815,0.495977],VPD=292.705): A interior or ring gear (yellow) with a mating spur gear (blue)
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// teeth1=18;
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// teeth2=30;
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// ps1=undef;
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// ps2=auto_profile_shift(teeth=teeth1);
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// mod=3;
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// d = gear_dist(mod=mod, teeth1=teeth1, teeth2=teeth2,profile_shift1=ps1, profile_shift2=ps2,helical=0, internal2=true);
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// ang = 0;
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// ring_gear2d(mod=mod, teeth=teeth2,profile_shift=ps2,helical=0,backing=4);
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// zrot(ang*360/teeth2)
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// color("lightblue")
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// fwd(d)
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// spur_gear2d(mod=mod, teeth=teeth1, profile_shift=ps1,gear_spin=-ang*360/teeth1,helical=0);
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// Continues:
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// Ring gears are subject to all the usual mesh requirements: the teeth must be the same size, the pressure angles must
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// match and they must have the same helical angle. The {{gear_dist()}} function can give the center separation of
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// a ring gear and its mating spur gear. But they also have additional complications that tend to arise when the number of
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// teeth is small or the teeth counts of the ring gear and spur gear are too close together. The mating spur gear must
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// have few enough teeth so that the teeth don't interfere on the other side of the ring. Very small spur gears can interfere
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// on the tips of the ring gear's teeth.
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// Figure(2D,Med,NoAxes,VPT=[-1.16111,0.0525612,0.495977],VPD=213.382): The red regions show interference between the two gears: the 18 tooth spur gear does not fit inside the 20 tooth ring gear.
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// teeth1=18;
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// teeth2=20;
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// ps1=undef;
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// ps2=auto_profile_shift(teeth=teeth1);
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// mod=3;
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// d = gear_dist(mod=mod, teeth1=teeth1, teeth2=teeth2,profile_shift1=ps1, profile_shift2=ps2,helical=0, internal2=true);
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// ang = 0;
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// color_overlaps(){
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// ring_gear2d(mod=mod, teeth=teeth2,profile_shift=ps2,helical=0,backing=4);
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// zrot(ang*360/teeth2)
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// fwd(d)
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// spur_gear2d(mod=mod, teeth=teeth1, profile_shift=ps1,gear_spin=-ang*360/teeth1,helical=0);
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// }
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// Figure(2D,Big,NoAxes,VPT=[10.8821,-26.1226,-0.0685569],VPD=43.9335,VPR=[0,0,16.8]): Interference at teeth tips, shown in red, with a 5 tooth and 19 tooth gear.
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// $fn=128;
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// teeth1=5;
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// teeth2=19;
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// ps1=0;
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// ps2=0;
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// mod=3;
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// d = gear_dist(mod=mod, teeth1=teeth1, teeth2=teeth2,profile_shift1=ps1, profile_shift2=ps2,helical=0, internal2=true);
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// echo(d=d);
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// ang = 1;
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// color_overlaps(){
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// ring_gear2d(mod=mod, teeth=teeth2,profile_shift=ps2,helical=0,backing=4);
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// zrot(ang*360/teeth2)
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// fwd(d)
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// spur_gear2d(mod=mod, teeth=teeth1, profile_shift=ps1,gear_spin=-ang*360/teeth1,helical=0);
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// }
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// Continues:
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// The tooth tip interference can often be controlled using profile shifting of the ring gear, but another requirement is
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// that the profile shift of the ring gear must be at least as big as the profile shift of the mated spur gear. In order
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// to ensure that this condition holds, you may need to use {{auto_profile_shift()}} to find the profile shift that is
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// automatically applied to the spur gear you want to use.
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// Figure(2D,Med,VPT=[4.02885,-46.6334,1.23363],VPR=[0,0,6.3],VPD=75.2671,NoAxes): Ring gear without profile shifting doesn't have room for the fat profile shifted teeth of the 5-tooth spur gear, with overlaps shown in red.
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// $fn=128;
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// teeth1=5;
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// teeth2=35;
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// ps1=undef;
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// ps2=0;
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// mod=3;
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// d=45-.7;
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// ang = .5;
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// color_overlaps(){
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// ring_gear2d(mod=mod, teeth=teeth2,profile_shift=ps2,helical=0,backing=4);
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// zrot(ang*360/teeth2)
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// fwd(d)
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// spur_gear2d(mod=mod, teeth=teeth1, profile_shift=ps1,gear_spin=-ang*360/teeth1,helical=0);
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// }
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// Figure(2D,Med,VPT=[9.87969,-45.6706,0.60448],VPD=82.6686,VPR=[0,0,11],NoAxes): When the ring gear is profile shifted to match the spur gear, then the gears mesh without interference.
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// $fn=128;
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// teeth1=5;
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// teeth2=35;
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// ps1=undef;
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// ps2=auto_profile_shift(teeth=teeth1);
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// mod=3;
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// d = gear_dist(mod=mod, teeth1=teeth1, teeth2=teeth2,profile_shift1=ps1, profile_shift2=ps2,helical=0, internal2=true);
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// ang = 1;
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// color_overlaps(){
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// ring_gear2d(mod=mod, teeth=teeth2,profile_shift=ps2,helical=0,backing=4);
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// zrot(ang*360/teeth2)
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// fwd(d)
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// spur_gear2d(mod=mod, teeth=teeth1, profile_shift=ps1,gear_spin=-ang*360/teeth1,helical=0);
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// }
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// Section: Gears
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@ -853,21 +939,26 @@ module spur_gear2d(
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// Topics: Gears, Parts
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// See Also: rack(), ring_gear2d(), spur_gear(), spur_gear2d(), bevel_gear()
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// Usage:
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// ring_gear(circ_pitch, teeth, thickness, [backing], [pressure_angle=], [helical=], [herringbone=], [profile_shift=], [clearance=], [backlash=]) [ATTACHMENTS];
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// ring_gear(mod=, teeth=, thickness=, backing=, [pressure_angle=], [helical=], [herringbone=], [profile_shift=], [clearance=], [backlash=]) [ATTACHMENTS];
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// ring_gear(diam_pitch=, teeth=, thickness=, backing=, [pressure_angle=], [helical=], [herringbone=], [profile_shift=], [clearance=], [backlash=]) [ATTACHMENTS];
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// ring_gear(circ_pitch, teeth, thickness, [backing|od=|or=|width=], [pressure_angle=], [helical=], [herringbone=], [profile_shift=], [clearance=], [backlash=]) [ATTACHMENTS];
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// ring_gear(mod=, teeth=, thickness=, [backing=|od=|or=|width=], [pressure_angle=], [helical=], [herringbone=], [profile_shift=], [clearance=], [backlash=]) [ATTACHMENTS];
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// ring_gear(diam_pitch=, teeth=, thickness=, [backing=|od=|or=|width=], [pressure_angle=], [helical=], [herringbone=], [profile_shift=], [clearance=], [backlash=]) [ATTACHMENTS];
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// Description:
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// Creates a 3D involute ring gear. Normally, you should just specify the
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// first 3 parameters `circ_pitch`, `teeth`, and `thickness`, and let the rest be default values.
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// Meshing gears must match in `circ_pitch`, `pressure_angle`, and `helical`, and be separated by
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// the sum of their profile shifts and pitch radii, which can be found with `mesh_radius()`.
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// Creates a 3D involute ring gear.
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// Meshing gears must have the same tooth size, pressure angle and helical angle as usual.
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// Additionally, you must have more teeth on an internal gear than its mating external gear, and
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// the profile shift on the ring gear must be at least as big as the profile shift on the mating gear.
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// You may need to use {{auto_profile_shift()}} to find this value if your mating gear has a small number of teeth.
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// The gear spacing is given by {{gear_dist()}}.
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// Arguments:
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// circ_pitch = The circular pitch, or distance between teeth around the pitch circle, in mm.
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// teeth = Total number of teeth around the spur gear.
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// thickness = Thickness of ring gear in mm
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// backing = The width of the ring gear backing, in mm.
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// pressure_angle = Controls how straight or bulged the tooth sides are. In degrees.
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// backing = The width of the ring gear backing. Default: height of teeth
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// ---
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// od = outer diameter of the ring
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// or = outer radius of the ring
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// width = width of the ring, measuring from tips of teeth to outside of ring.
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// pressure_angle = Controls how straight or bulged the tooth sides are. In degrees.
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// helical = The angle of the rack teeth away from perpendicular to the gear axis of rotation. Stretches out the tooth shapes. Used to match helical spur gear pinions. Default: 0
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// herringbone = If true, and helical is set, creates a herringbone gear.
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// profile_shift = Profile shift factor x for tooth profile.
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@ -887,21 +978,22 @@ module spur_gear2d(
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// Example(Med): Tooth Profile Shifting
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// ring_gear(circ_pitch=5, teeth=48, thickness=10, profile_shift=0.5);
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// Example(Med): Helical Ring Gear
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// ring_gear(circ_pitch=5, teeth=48, thickness=10, helical=30);
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// ring_gear(circ_pitch=5, teeth=48, thickness=15, helical=30);
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// Example(Med): Herringbone Ring Gear
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// ring_gear(circ_pitch=5, teeth=48, thickness=10, helical=30, herringbone=true);
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// ring_gear(circ_pitch=5, teeth=48, thickness=30, helical=30, herringbone=true);
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module ring_gear(
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circ_pitch,
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teeth,
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thickness = 10,
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backing = 10,
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backing,
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pressure_angle,
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helical,
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herringbone = false,
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profile_shift,
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clearance,
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backlash = 0.0,
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or,od,width,
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pitch,
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diam_pitch,
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mod,
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@ -919,7 +1011,6 @@ module ring_gear(
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checks =
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assert(is_integer(teeth) && teeth>3)
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assert(is_finite(thickness) && thickness>0)
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assert(is_finite(backing) && backing>0)
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assert(is_finite(PA) && PA>=0 && PA<90, "Bad pressure_angle value.")
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assert(is_finite(helical) && abs(helical)<90)
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assert(is_bool(herringbone))
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@ -927,9 +1018,24 @@ module ring_gear(
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assert(is_finite(backlash) && backlash>=0)
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assert(is_finite(profile_shift) && abs(profile_shift)<1)
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assert(slices==undef || (is_integer(slices) && slices>0))
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assert(num_defined([backing,or,od,width])<=1, "Cannot define more than one of backing, or, od and width")
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assert(is_finite(gear_spin));
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pr = pitch_radius(circ_pitch, teeth, helical=helical);
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ar = outer_radius(circ_pitch, teeth, helical=helical, profile_shift=profile_shift, internal=true);
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rr=_root_radius(circ_pitch, teeth, clearance, profile_shift=profile_shift, internal=true);
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or = is_def(or) ?
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assert(is_finite(or) && or>ar, "or is invalid or too small for teeth")
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or
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: is_def(od) ?
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assert(is_finite(od) && od>2*ar, "od is invalid or too small for teeth")
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od/2
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: is_def(width) ?
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assert(is_finite(width) && width>ar-rr, "width is invalid or too small for teeth")
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rr+width
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: is_def(backing) ?
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assert(all_positive([backing]), "backing must be a positive value")
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ar+backing
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: 2*ar - rr; // default case
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circum = 2 * PI * pr;
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twist = 360*thickness*tan(helical)/circum;
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slices = default(slices, ceil(twist/360*segs(pr)+1));
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@ -939,7 +1045,7 @@ module ring_gear(
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zflip_copy() down(0.01)
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linear_extrude(height=thickness/2, center=false, twist=twist/2, slices=ceil(slices/2), convexity=teeth/4) {
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difference() {
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circle(r=ar+backing);
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circle(r=or);
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spur_gear2d(
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circ_pitch = circ_pitch,
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teeth = teeth,
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@ -956,7 +1062,7 @@ module ring_gear(
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zrot(twist/2)
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linear_extrude(height=thickness,center=true, twist=twist, convexity=teeth/4) {
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difference() {
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circle(r=ar+backing);
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circle(r=or);
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spur_gear2d(
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circ_pitch = circ_pitch,
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teeth = teeth,
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@ -981,21 +1087,26 @@ module ring_gear(
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// Topics: Gears, Parts
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// See Also: rack(), spur_gear(), spur_gear2d(), bevel_gear()
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// Usage:
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// ring_gear2d(circ_pitch, teeth, [backing], [pressure_angle=], [helical=], [profile_shift=], [clearance=], [backlash=]) [ATTACHMENTS];
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// ring_gear2d(mod=, teeth=, [backing=], [pressure_angle=], [helical=], [profile_shift=], [clearance=], [backlash=]) [ATTACHMENTS];
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// ring_gear2d(diam_pitch=, teeth=, [backing=], [pressure_angle=], [helical=], [profile_shift=], [clearance=], [backlash=]) [ATTACHMENTS];
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// ring_gear2d(circ_pitch, teeth, [backing|od=|or=|width=], [pressure_angle=], [helical=], [profile_shift=], [clearance=], [backlash=]) [ATTACHMENTS];
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// ring_gear2d(mod=, teeth=, [backing=|od=|or=|width=], [pressure_angle=], [helical=], [profile_shift=], [clearance=], [backlash=]) [ATTACHMENTS];
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// ring_gear2d(diam_pitch=, teeth=, [backing=|od=|or=|width=], [pressure_angle=], [helical=], [profile_shift=], [clearance=], [backlash=]) [ATTACHMENTS];
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// Description:
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// Creates a 2D involute ring gear. Normally, you should just specify the
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// first 2 parameters `circ_pitch` and `teeth`, and let the rest be default values.
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// Meshing gears must match in `circ_pitch`, `pressure_angle`, and `helical`, and be separated by
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// the sum of their profile shifts and pitch radii, which can be found with `mesh_radius()`.
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// Creates a 2D involute ring gear.
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// Meshing gears must have the same tooth size, pressure angle and helical angle as usual.
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// Additionally, you must have more teeth on an internal gear than its mating external gear, and
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// the profile shift on the ring gear must be at least as big as the profile shift on the mating gear.
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// You may need to use {{auto_profile_shift()}} to find this value if your mating gear has a small number of teeth.
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// The gear spacing is given by {{gear_dist()}}.
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// Arguments:
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// circ_pitch = The circular pitch, or distance between teeth around the pitch circle, in mm.
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// teeth = Total number of teeth around the spur gear.
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// backing = The width of the ring gear backing, in mm.
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// pressure_angle = Controls how straight or bulged the tooth sides are. In degrees.
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// backing = The width of the ring gear backing. Default: height of teeth
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// ---
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// od = outer diameter of the ring
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// or = outer radius of the ring
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// width = width of the ring, measuring from tips of teeth to outside of ring.
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// helical = The angle of the rack teeth away from perpendicular to the gear axis of rotation. Stretches out the tooth shapes. Used to match helical spur gear pinions. Default: 0
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// pressure_angle = Controls how straight or bulged the tooth sides are. In degrees.
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// profile_shift = Profile shift factor x for tooth profile.
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// clearance = Gap between top of a tooth on one gear and bottom of valley on a meshing gear (in millimeters)
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// backlash = Gap between two meshing teeth, in the direction along the circumference of the pitch circle
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@ -1003,21 +1114,32 @@ module ring_gear(
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// mod = The metric module/modulus of the gear, or mm of pitch diameter per tooth.
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// anchor = Translate so anchor point is at origin (0,0,0). See [anchor](attachments.scad#subsection-anchor). Default: `CENTER`
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// spin = Rotate this many degrees around the Z axis after anchor. See [spin](attachments.scad#subsection-spin). Default: `0`
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// Example(2D;Big):
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// circ_pitch=5; teeth1=50; teeth2=16;
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// pr1 = pitch_radius(circ_pitch, teeth1);
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// pr2 = pitch_radius(circ_pitch, teeth2);
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// Example(2D,Big): Meshing a ring gear with a spur gear
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// circ_pitch=5; teeth1=50; teeth2=18;
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// dist = gear_dist(circ_pitch=circ_pitch, teeth1, teeth2, internal1=true);
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// ring_gear2d(circ_pitch=circ_pitch, teeth=teeth1);
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// back(pr1-pr2) spur_gear2d(circ_pitch=circ_pitch, teeth=teeth2);
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// color("lightblue")back(dist)
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// spur_gear2d(circ_pitch=circ_pitch, teeth=teeth2);
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// Example(2D,Med,VPT=[-0.117844,-0.439102,-0.372203],VPD=192.044): Meshing a ring gear with an auto-profile-shifted spur gear:
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// teeth1=7; teeth2=15;
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// ps1=undef; // Allow auto profile shifting for first gear
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// ps2=auto_profile_shift(teeth=teeth1);
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// mod=3;
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// d = gear_dist(mod=mod, teeth1=teeth1, teeth2=teeth2, profile_shift1=ps1, profile_shift2=ps2, internal2=true);
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// ring_gear2d(mod=mod, teeth=teeth2,profile_shift=ps2);
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// color("lightblue") fwd(d)
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// spur_gear2d(mod=mod, teeth=teeth1, profile_shift=ps1);
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module ring_gear2d(
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circ_pitch,
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teeth,
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backing = 10,
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backing,
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pressure_angle,
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helical,
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profile_shift,
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clearance,
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backlash = 0.0,
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or,od,width,
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pitch,
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diam_pitch,
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mod,
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@ -1031,7 +1153,7 @@ module ring_gear2d(
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profile_shift = default(profile_shift, auto_profile_shift(teeth,PA,helical));
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checks =
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assert(is_integer(teeth) && teeth>3)
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assert(is_finite(backing) && backing>0)
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assert(num_defined([backing,or,od,width])<=1, "Cannot define more than one of backing, or, od and width")
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assert(is_finite(PA) && PA>=0 && PA<90, "Bad pressure_angle value.")
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assert(is_finite(helical) && abs(helical)<90)
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assert(clearance==undef || (is_finite(clearance) && clearance>=0))
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@ -1040,10 +1162,24 @@ module ring_gear2d(
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assert(is_finite(gear_spin));
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pr = pitch_radius(circ_pitch, teeth, helical=helical);
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ar = outer_radius(circ_pitch, teeth, helical=helical, profile_shift=profile_shift, internal=true);
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rr=_root_radius(circ_pitch, teeth, clearance, profile_shift=profile_shift, internal=true);
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or = is_def(or) ?
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assert(is_finite(or) && or>ar, "or is invalid or too small for teeth")
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or
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: is_def(od) ?
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assert(is_finite(od) && od>2*ar, "od is invalid or too small for teeth")
|
||||
od/2
|
||||
: is_def(width) ?
|
||||
assert(is_finite(width) && width>ar-rr, "width is invalid or too small for teeth")
|
||||
rr+width
|
||||
: is_def(backing) ?
|
||||
assert(all_positive([backing]), "backing must be a positive value")
|
||||
ar+backing
|
||||
: 2*ar - rr; // default case
|
||||
attachable(anchor,spin, two_d=true, r=pr) {
|
||||
zrot(gear_spin)
|
||||
difference() {
|
||||
circle(r=ar+backing);
|
||||
circle(r=or);
|
||||
spur_gear2d(
|
||||
circ_pitch = circ_pitch,
|
||||
teeth = teeth,
|
||||
|
|
@ -1060,6 +1196,8 @@ module ring_gear2d(
|
|||
}
|
||||
|
||||
|
||||
|
||||
|
||||
// Function&Module: rack()
|
||||
// Synopsis: Creates a straight or helical gear rack.
|
||||
// SynTags: Geom, VNF
|
||||
|
|
@ -2722,7 +2860,7 @@ function outer_radius(circ_pitch, teeth, clearance, internal=false, helical=0, p
|
|||
let( circ_pitch = circular_pitch(pitch, mod, circ_pitch, diam_pitch) )
|
||||
pitch_radius(circ_pitch, teeth, helical) + (
|
||||
internal
|
||||
? _dedendum(circ_pitch, clearance, profile_shift=profile_shift)
|
||||
? _dedendum(circ_pitch, clearance, profile_shift=-profile_shift)
|
||||
: _adendum(circ_pitch, profile_shift=profile_shift)
|
||||
);
|
||||
|
||||
|
|
@ -2760,7 +2898,7 @@ function _root_radius(circ_pitch, teeth, clearance, internal=false, helical=0, p
|
|||
let( circ_pitch = circular_pitch(pitch, mod, circ_pitch, diam_pitch) )
|
||||
pitch_radius(circ_pitch, teeth, helical) - (
|
||||
internal
|
||||
? _adendum(circ_pitch, profile_shift=profile_shift)
|
||||
? _adendum(circ_pitch, profile_shift=-profile_shift)
|
||||
: _dedendum(circ_pitch, clearance, profile_shift=profile_shift)
|
||||
);
|
||||
|
||||
|
|
@ -2892,7 +3030,10 @@ function worm_gear_thickness(circ_pitch, teeth, worm_diam, worm_arc=60, crowning
|
|||
// Calculate the distance between the centers of two spur gears gears or helical gears with parallel axes,
|
||||
// taking into account profile shifting and helical angle. You can give the helical angle as either positive or negative.
|
||||
// If you set one of the tooth counts to zero than that gear will be treated as a rack and the distance returned is the
|
||||
// distance between the rack's pitch line and the gear's center.
|
||||
// distance between the rack's pitch line and the gear's center. If you set internal1 or internal2 to true then the
|
||||
// specified gear is a ring gear; the returned distance is still the distance between the centers of the gears. Note that
|
||||
// for a regular gear and ring gear to be compatible the ring gear must have more teeth and at least as much profile shift
|
||||
// as the regular gear.
|
||||
// Arguments:
|
||||
// teeth1 = Total number of teeth in the first gear. If given 0, we assume this is a rack or worm.
|
||||
// teeth2 = Total number of teeth in the second gear. If given 0, we assume this is a rack or worm.
|
||||
|
|
@ -2902,6 +3043,8 @@ function worm_gear_thickness(circ_pitch, teeth, worm_diam, worm_arc=60, crowning
|
|||
// --
|
||||
// diam_pitch = The diametral pitch, or number of teeth per inch of pitch diameter. Note that the diametral pitch is a completely different thing than the pitch diameter.
|
||||
// mod = The metric module/modulus of the gear, or mm of pitch diameter per tooth.
|
||||
// internal1 = first gear is an internal (ring) gear. Default: false
|
||||
// internal2 = second gear is an internal (ring) gear. Default: false
|
||||
// circ_pitch = distance between teeth around the pitch circle.
|
||||
// pressure_angle = The pressure angle of the gear.
|
||||
// Example(2D): Spur gears (with automatic profile shifting on both)
|
||||
|
|
@ -2909,7 +3052,7 @@ function worm_gear_thickness(circ_pitch, teeth, worm_diam, worm_arc=60, crowning
|
|||
// d = gear_dist(circ_pitch=circ_pitch, teeth1, teeth2);
|
||||
// spur_gear2d(circ_pitch, teeth1, gear_spin=-90);
|
||||
// right(d) spur_gear2d(circ_pitch, teeth2, gear_spin=90-180/teeth2);
|
||||
// Example(2D): Helical gears (with auto profile shifting on one of the gears)
|
||||
// Example: Helical gears (with auto profile shifting on one of the gears)
|
||||
// circ_pitch=5; teeth1=7; teeth2=24; helical=37;
|
||||
// d = gear_dist(circ_pitch=circ_pitch, teeth1, teeth2, helical);
|
||||
// spur_gear(circ_pitch, teeth1, helical=helical, gear_spin=-90);
|
||||
|
|
@ -2929,7 +3072,7 @@ function worm_gear_thickness(circ_pitch, teeth, worm_diam, worm_arc=60, crowning
|
|||
// d = gear_dist(mod=mod, teeth, 0);
|
||||
// rack2d(mod=mod, teeth=5, bottom=9);
|
||||
// back(d) spur_gear2d(mod=mod, teeth=teeth, gear_spin=180/teeth);
|
||||
// Example(3D,VPT=[-0.0608489,1.3772,-3.68839],VPR=[63.4,0,29.7],VPD=113.336): Profile shifted helical gear and rack
|
||||
// Example(VPT=[-0.0608489,1.3772,-3.68839],VPR=[63.4,0,29.7],VPD=113.336): Profile shifted helical gear and rack
|
||||
// mod=3; teeth=8; helical=29;
|
||||
// d = gear_dist(mod=mod, teeth, 0, helical);
|
||||
// rack(mod=mod, teeth=5, helical=helical, orient=FWD);
|
||||
|
|
@ -2941,6 +3084,8 @@ function gear_dist(
|
|||
helical=0,
|
||||
profile_shift1,
|
||||
profile_shift2,
|
||||
internal1=false,
|
||||
internal2=false,
|
||||
pressure_angle=20,
|
||||
diam_pitch,
|
||||
circ_pitch,
|
||||
|
|
@ -2948,11 +3093,23 @@ function gear_dist(
|
|||
) =
|
||||
assert(all_nonnegative([teeth1,teeth2]),"Must give nonnegative values for teeth")
|
||||
assert(teeth1>0 || teeth2>0, "One of the teeth counts must be nonzero")
|
||||
assert(is_bool(internal1))
|
||||
assert(is_bool(internal2))
|
||||
assert(!(internal1&&internal2), "Cannot specify both gears as internal")
|
||||
assert(!(internal1 || internal2) || (teeth1>0 && teeth2>0), "Cannot specify internal gear with rack (zero tooth count)")
|
||||
let(
|
||||
mod = module_value(mod=mod,circ_pitch= circ_pitch, diam_pitch=diam_pitch),
|
||||
profile_shift1 = default(profile_shift1, auto_profile_shift(teeth1,pressure_angle,helical)),
|
||||
profile_shift2 = default(profile_shift2, auto_profile_shift(teeth2,pressure_angle,helical))
|
||||
profile_shift2 = default(profile_shift2, auto_profile_shift(teeth2,pressure_angle,helical)),
|
||||
teeth1 = internal2? -teeth1 : teeth1,
|
||||
teeth2 = internal1? -teeth2 : teeth2
|
||||
)
|
||||
assert(teeth1+teeth2>0, "Internal gear must have more teeth than the mated external gear")
|
||||
let(
|
||||
profile_shift1 = internal2? -profile_shift1 : profile_shift1,
|
||||
profile_shift2 = internal1? -profile_shift2 : profile_shift2
|
||||
)
|
||||
assert(profile_shift1+profile_shift2>=0, "Internal gear must have profile shift equal or greater than mated external gear")
|
||||
teeth1==0 || teeth2==0? pitch_radius(mod=mod, teeth=teeth1+teeth2, helical=helical) + (profile_shift1+profile_shift2)*mod
|
||||
:
|
||||
let(
|
||||
|
|
@ -2961,6 +3118,23 @@ function gear_dist(
|
|||
)
|
||||
mod*(teeth1+teeth2)*cos(pa_transv)/cos(pa_eff)/cos(helical)/2;
|
||||
|
||||
function _invol(a) = tan(a) - a*PI/180;
|
||||
|
||||
function _working_pressure_angle(teeth1,profile_shift1, teeth2, profile_shift2, pressure_angle, helical) =
|
||||
let(
|
||||
pressure_angle = atan(tan(pressure_angle)/cos(helical))
|
||||
)
|
||||
teeth1==0 || teeth2==0 ? pressure_angle
|
||||
:
|
||||
let(
|
||||
rhs = 2*(profile_shift1+profile_shift2)/(teeth1+teeth2)*cos(helical)*tan(pressure_angle) + _invol(pressure_angle),
|
||||
f=echo(rhs=rhs, ps=profile_shift1, profile_shift2),
|
||||
pa_eff = root_find(function (x) _invol(x)-rhs, 5, 75)
|
||||
)
|
||||
pa_eff;
|
||||
|
||||
|
||||
|
||||
function _invol(a) = tan(a) - a*PI/180;
|
||||
|
||||
function _working_pressure_angle(teeth1,profile_shift1, teeth2, profile_shift2, pressure_angle, helical) =
|
||||
|
|
@ -3119,3 +3293,4 @@ function auto_profile_shift(teeth, pressure_angle=20, helical=0, min_teeth) =
|
|||
|
||||
|
||||
// vim: expandtab tabstop=4 shiftwidth=4 softtabstop=4 nowrap
|
||||
|
||||
|
|
|
|||
Loading…
Reference in a new issue