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bevel gear text added

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Adrian Mariano 2023-10-04 23:55:13 -04:00
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1 changed files with 61 additions and 3 deletions
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gears.scad
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@ -81,6 +81,11 @@ function _inherit_gear_thickness(thickness) =
// * [Worm drive](https://www.tec-science.com/mechanical-power-transmission/gear-types/worms-and-worm-gears/)
// - SDPSI (A long document covering a variety of gear types and gear calculations)
// * [Elements of Gear Technology](https://www.sdp-si.com/resources/elements-of-metric-gear-technology/index.php)
// - Crown Face Gears
// * [Crown Gearboxes](https://mag.ebmpapst.com/en/industries/drives/crown-gearboxes-efficiency-energy-savings-decentralized-drive-technology_14834/)
// * [Crown gear pressure angle](https://mag.ebmpapst.com/en/industries/drives/the-formula-for-the-pressure-angle_14624/)
// * [Face Gears: Geometry and Strength](https://www.geartechnology.com/ext/resources/issues/0107x/kissling.pdf)
// Subsection: Involute Spur Gears
// The simplest gear form is the involute spur gear, which is an extrusion of a two dimensional form.
// Figure(3D,Med,NoAxes,VPT=[4.62654,-1.10349,0.281802],VPR=[55,0,25],VPD=236.957): Involute Spur Gear
@ -503,6 +508,59 @@ function _inherit_gear_thickness(thickness) =
// worm wheel is still trying to move due to inertia, which can create large loads that fracture the worm.
// In such cases, the worm cannot be stopped abruptly but must rotate a little further (called "over travel")
// after switching off the drive
// Subsection: Bevel Gears
// Bevel gearing is another way of dealing with intersecting gear shafts. For bevel gears, the teeth centers lie on
// the surface of an imaginary cone, which is the pitch cone of the bevel gear. Two bevel gears mesh when their pitch cones
// touch along their length. The teeth of bevel gears narrow as they get closer to the center of the gear.
// Tooth dimensions and pitch diameter are referenced to the outer end of the teeth.
// Bevel gears can be made with straight teeth, analogous to spur gears, and with the
// same disadvantage of sudden full contact that is noisy. Spiral teeth are analogous to helical
// teeth on cylindrical gears: the teeth engage gradually and smoothly, transmitting motion more smoothly
// and quietly. Also like helical gears, they have the disadvantage of introducing axial forces, and
// usually they can only operate in one rotation direction.
// A third type of tooth is the zerol tooth, which has curved teeth like the spiral teeth,
// but with a zero angle. These share advantages of straight teeth and spiral teeth: they are quiet like
// straight teeth but they lack the axial thrust of spiral gears, and they can operate in both directions.
// They are also reportedly stronger than either spiral or bevel gears.
// Figure(3D,Med,VPT=[-5.10228,-3.09311,3.06426],VPR=[67.6,0,131.9],VPD=237.091,NoAxes): Straight tooth bevel gear with 45 degree angled teeth. To get a gear like this you must specify a spiral angle of zero and a cutter radius of zero.
// bevel_gear(mod=3,teeth=35,face_width=20,spiral_angle=0,cutter_radius=0);
// Figure(3D,Med,VPT=[-5.10228,-3.09311,3.06426],VPR=[67.6,0,131.9],VPD=237.091,NoAxes): Straight tooth bevel gear with 45 degree angled teeth. A gear like this has a positive spiral angle, which determines how sloped the teeth are and a positive cutter radius, which determines how curved the teeth are.
// bevel_gear(mod=3,teeth=35,face_width=20);
// Figure(3D,Med,VPT=[-5.10228,-3.09311,3.06426],VPR=[67.6,0,131.9],VPD=237.091,NoAxes): Zerol tooth bevel gear with 45 degree angled teeth. A gear like this has a spiral angle of zero, but a positive cutter radius, which determines how curved the teeth are.
// bevel_gear(mod=3,teeth=35,face_width=20,spiral_angle=0);
// Continues:
// Bevel gears have demanding requirements for successful mating of two gears. Of course the tooth size
// and pressure angle must match. But beyond that, their pitch cones have to meet at their points.
// This means that if you specify the tooth counts
// of two gears and the desired shaft angle, then that information completely determines the pitch cones, and hence
// the geometry of the gear. You cannot simply mate two arbitary gears that have the same tooth size
// and pressure angle like you can with helical gears: the gears must be designed in pairs to work together.
// .
// It is most common to design bevel gears so operate with their shafts at 90 degree angles, but
// this is not required, and you can design pairs of bevel gears for any desired shaft angle.
// Note, however, that given a pair of teeth counts, a bevel gear pair is not possible at all angles.
// Figure(3D,Med,VPT=[-40.9281,-1.23739,2.11767],VPR=[68.3,0,119.8],VPD=54.2389,NoAxes): Two zerol bevel gears mated with shafts at 90 degrees.
// bevel_gear(mod=3,teeth=35,face_width=10,spiral_angle=0,mate_teeth=15);
// color("lightblue")left(pitch_radius(mod=3,teeth=35))up(pitch_radius(mod=3,teeth=15))
// yrot(90)zrot(360/15/2)bevel_gear(mod=3,teeth=15,face_width=10,spiral_angle=0,cutter_radius=-30,mate_teeth=35);
// Figure(3D,Med,VPT=[1.55215,1.94725,16.4524],VPR=[76,0,181.4],VPD=263.435): Two zerol bevel gears mated with shafts at a 35 deg angle.
// function bevel_angles(z1,z2,shaft) =
// [atan(sin(shaft)/((z2/z1)+cos(shaft))),
// atan(sin(shaft)/((z1/z2)+cos(shaft)))];
// angles = bevel_angles(35,15,115);
// bevel_gear(mod=3,teeth=35,face_width=10,spiral_angle=0,pitch_angle=angles[0],cutter_radius=30);
// cyl(h=40,d=3,$fn=16,anchor=BOT);
// color("lightblue")
// left(pitch_radius(mod=3,teeth=35))yrot(20)up(pitch_radius(mod=3,teeth=15))
// yrot(90)zrot(360/15/2){
// bevel_gear(mod=3,teeth=15,face_width=10,spiral_angle=0,cutter_radius=-30,pitch_angle=(angles[1]));
// cyl(h=60,d=3,$fn=16,anchor=BOT);
// }
// Continues:
// In the above figure you can see a gear that is very flat. A bevel gear like this is called a planar gear or
// sometimes also a crown gear. The latter term may be confusing because it also refers to a similar looking
// but very different type of gear that is described below. A planar bevel gear can only mate with another
// compatible bevel gear, and never at a 90 degree angle.
// Subsection: Crown Gears (Face Gears)
// Crown gears, sometimes called Face Crown Gears or just Face Gears, are gears with teeth pointing straight up so
// the gear resembles a crown. This type of gear is not the same as a bevel gear with vertical teeth, which would mate
@ -524,7 +582,7 @@ function _inherit_gear_thickness(thickness) =
// Note that the geometry of these crown gears is tricky and not well documented by sources we have found.
// If you know something about crown gears that could improve the implementation, please open an issue
// on github.
// Subsection: Backlash (Fitting Real Gears Together)
// Section: Backlash (Fitting Real Gears Together)
// You may have noticed that the example gears shown fit together perfectly, making contact on both sides of
// the teeth. Real gears need space between the teeth to prevent the gears from jamming, to provide space
// for lubricant, and to provide allowance for fabrication error. This space is called backlash. Excessive backlash
@ -2258,8 +2316,8 @@ module crown_gear(
// pressure_angle = Controls how straight or bulged the tooth sides are. In degrees. Default: 20
// clearance = Clearance gap at the bottom of the inter-tooth valleys. Default: module/4
// backlash = Gap between two meshing teeth, in the direction along the circumference of the pitch circle. Default: 0
// cutter_radius = Radius of spiral arc for teeth. If 0, then gear will not be spiral. Default: 0
// spiral_angle = The base angle for spiral teeth. Default: 0
// cutter_radius = Radius of spiral arc for teeth. If 0, then gear will have straight teeth. Default: 30
// spiral_angle = The base angle for spiral teeth. If zero the teeth will be zerol or straight. Default: 30
// left_handed = If true, the gear returned will have a left-handed spiral. Default: false
// slices = Number of vertical layers to divide gear into. Useful for refining gears with `spiral`. Default: 1
// internal = If true, create a mask for difference()ing from something else.