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Merge pull request #1241 from adrianVmariano/master

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gear fixes
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Revar Desmera 2023-08-07 21:44:42 -07:00 committed by GitHub
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2 changed files with 23 additions and 9 deletions
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8
attachments.scad
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@ -2278,6 +2278,14 @@ module corner_profile(corners=CORNERS_ALL, except=[], r, d, convexity=10) {
// * Rotates this part so it's anchor direction vector exactly opposes the parent's anchor direction vector.
// * Rotates this part so it's anchor spin matches the parent's anchor spin.
// .
// This module is also responsible for handing coloring of objects with {{recolor()}} and {{color_this()}}, and
// it is responsible for processing tags and determining whether the object should
// display or not in the current context. The determination to display the attachable object
// occurs in this module, which means that an object which does not display (e.g. a "remove" tagged object
// inside {{diff()}} cannot have internal {{tag()}} calls that change its tags and cause submodel
// portions to display: the entire child simply does not run.
// For a step-by-step explanation of attachments, see the [Attachments Tutorial](Tutorial-Attachments).
//
// Arguments:

20
gears.scad
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@ -72,6 +72,7 @@ function _inherit_gear_thickness(thickness) =
// this section provides the minimal information needed for gear making. If you want more information about the
// details of gears, consult the references below, which are the ones that we consulted when writing the library code.
// - Tec Science
// * [Involute Gears](https://www.tec-science.com/mechanical-power-transmission/involute-gear/geometry-of-involute-gears/)
// * [Gear engagement](https://www.tec-science.com/mechanical-power-transmission/involute-gear/meshing-line-action-contact-pitch-circle-law/)
// * [Gears meshing with racks](https://www.tec-science.com/mechanical-power-transmission/involute-gear/rack-meshing/)
// * [Gear undercutting](https://www.tec-science.com/mechanical-power-transmission/involute-gear/undercut/)
@ -211,7 +212,7 @@ function _inherit_gear_thickness(thickness) =
// be automatically incorporated. (Consider the situation where one gear mates with multiple other gears.) With modest
// profile shifts, you can probably ignore this adjustment, but with more extreme profile shifts, it may be important.
// You can compute the shortening parameter using {{gear_shorten()}}. Note that the actual shortening distance is obtained
// by scaling the shortening fator by the gear's module.
// by scaling the shortening factor by the gear's module.
// Figure(2D,Big,NoAxes,VPT=[55.8861,-4.31463,8.09832],VPR=[0,0,0],VPD=325.228): With large profile shifts the teeth need to be shortened or they don't have clearance in the valleys of the teeth in the meshing gear.
// teeth1=25;
// teeth2=19;
@ -1692,7 +1693,7 @@ function rack2d(
tthick = trans_pitch/PI * (PI/2 + 2*profile_shift * tan(PA)) - backlash,
l = teeth * trans_pitch,
ax = ang_adj_to_opp(trans_pa, adendum),
dx = ang_adj_to_opp(trans_pa, dedendum),
dx = dedendum*tan(trans_pa),
poff = tthick/2 - backlash,
tooth = [
[-trans_pitch/2, -dedendum],
@ -2567,7 +2568,7 @@ function _gear_tooth_profile(
rrad = _root_radius(circ_pitch, teeth, clearance, helical=helical, profile_shift=profile_shift, internal=internal),
srad = max(rrad,brad),
tthick = circ_pitch/PI / cos(helical) * (PI/2 + 2*profile_shift * tan(pressure_angle)) - backlash,
tthick = circ_pitch/PI / cos(helical) * (PI/2 + 2*profile_shift * tan(pressure_angle)) + (internal?backlash:-backlash),
tang = tthick / prad / 2 * 180 / PI,
// Generate a lookup table for the involute curve angles, by radius
@ -2662,9 +2663,11 @@ function _gear_tooth_profile(
? [last(line1), isect_pt, line2[0]]
: [line2[0], isect_pt, line1[0]],
rounded_tooth_half = deduplicate([
if (!internal) each arc(n=8, r=round_r, corner=rcorner),
if (!internal && round_r>0) each arc(n=8, r=round_r, corner=rcorner),
if (!internal && round_r<=0) isect_pt,
each tooth_half_raw,
if (internal) each arc(n=8, r=round_r, corner=rcorner),
if (internal && round_r>0) each arc(n=8, r=round_r, corner=rcorner),
if (internal && round_r<=0) isect,
]),
// Strip "jaggies" if found.
@ -3164,6 +3167,9 @@ function worm_gear_thickness(circ_pitch, teeth, worm_diam, worm_arc=60, crowning
// 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.
// .
// The backlash parameter computes the distance offset that produces a total backlash of `2*backlash` in the
// two gear mesh system. This is equivalent to giving the same backlash argument to both gears.
// 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.
@ -3177,7 +3183,7 @@ function worm_gear_thickness(circ_pitch, teeth, worm_diam, worm_arc=60, crowning
// internal1 = first gear is an internal (ring) gear. Default: false
// internal2 = second gear is an internal (ring) gear. Default: false
// pressure_angle = The pressure angle of the gear.
// backlash = Add extra space to produce the specified backlash
// backlash = Add extra space to produce a total of 2*backlash between the two gears.
// Example(2D,NoAxes): Spur gears (with automatic profile shifting on both)
// circ_pitch=5; teeth1=7; teeth2=24;
// d = gear_dist(circ_pitch=circ_pitch, teeth1, teeth2);
@ -3248,7 +3254,7 @@ function gear_dist(
pa_eff = _working_pressure_angle(teeth1,profile_shift1,teeth2,profile_shift2,pressure_angle,helical),
pa_transv = atan(tan(pressure_angle)/cos(helical))
)
mod*(teeth1+teeth2)*cos(pa_transv)/cos(pa_eff)/cos(helical)/2 + backlash*cos(helical)/2/tan(pressure_angle);
mod*(teeth1+teeth2)*cos(pa_transv)/cos(pa_eff)/cos(helical)/2 + backlash*cos(helical)/tan(pressure_angle);
function _invol(a) = tan(a) - a*PI/180;