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fix backlash bug in rack2d() & remove echoes

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Adrian Mariano 2023-08-09 23:31:12 -04:00
parent ada1a2e3fc
commit 6c01ef99a0
1 changed files with 10 additions and 10 deletions
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20
gears.scad
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@ -1694,7 +1694,7 @@ function rack2d(
l = teeth * trans_pitch,
ax = ang_adj_to_opp(trans_pa, adendum),
dx = dedendum*tan(trans_pa),
poff = tthick/2 - backlash,
poff = tthick/2,
tooth = [
[-trans_pitch/2, -dedendum],
if (rounding) each arc(n=4, r=clear, corner=[
@ -2233,7 +2233,6 @@ module worm(
assert(is_finite(gear_spin))
assert(is_finite(profile_shift) && abs(profile_shift)<1);
helical = asin(starts * circ_pitch / PI / d);
fda= echo(helical=helical);
trans_pitch = circ_pitch / cos(helical);
vnf = worm(
circ_pitch=circ_pitch,
@ -2370,7 +2369,6 @@ function worm_gear(
pr = pitch_radius(circ_pitch, teeth,helical),
hob_rad = worm_diam / 2 + crowning,
thickness = worm_gear_thickness(circ_pitch=circ_pitch, teeth=teeth, worm_diam=worm_diam, worm_arc=worm_arc, crowning=crowning, clearance=clearance),
dfda=echo("------->"),
tooth_profile = _gear_tooth_profile(
circ_pitch=circ_pitch,
teeth=teeth,
@ -2381,7 +2379,6 @@ function worm_gear(
profile_shift=profile_shift,
center=true
),
feeg=echo("<----------"),
tbot = min(column(tooth_profile,1)),
arcthick = hob_rad * sin(worm_arc/2) * 2,
twist = sin(helical)*arcthick / (2*PI*pr) * 360,
@ -2569,8 +2566,6 @@ function _gear_tooth_profile(
prad = pitch_radius(circ_pitch, teeth, helical=helical),
brad = _base_radius(circ_pitch, teeth, pressure_angle, helical=helical),
rrad = _root_radius(circ_pitch, teeth, clearance, helical=helical, profile_shift=profile_shift, internal=internal),
fgdg= echo(pitchrad=prad,outerrad=arad,rootrad=rrad),
srad = max(rrad,brad),
tthick = circ_pitch/PI / cos(helical) * (PI/2 + 2*profile_shift * tan(pressure_angle)) + (internal?backlash:-backlash),
tang = tthick / prad / 2 * 180 / PI,
@ -3176,14 +3171,15 @@ 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.
// circ_pitch = distance between teeth around the pitch circle.
// pressure_angle = The pressure angle of the gear.
// backlash = Add extra space to produce a total of 2*backlash between the two gears.
function worm_dist(d,starts,teeth,mod,profile_shift=0,diam_pitch,circ_pitch,pressure_angle=20) =
function worm_dist(d,starts,teeth,mod,profile_shift=0,diam_pitch,circ_pitch,pressure_angle=20,backlash=0) =
let(
mod = module_value(mod=mod,diam_pitch=diam_pitch,circ_pitch=circ_pitch),
lead_angle = asin(mod*starts/d),
pitch_diam = mod*teeth/cos(lead_angle)
)
(d+pitch_diam)/2 + profile_shift*mod;
(d+pitch_diam)/2 + profile_shift*mod + backlash * (cos(lead_angle)+cos(90-lead_angle)) / tan(pressure_angle);
@ -3333,12 +3329,14 @@ function _working_pressure_angle(teeth1,profile_shift1, teeth2, profile_shift2,
// mod = The metric module/modulus of the gear, or mm of pitch diameter per tooth.
// circ_pitch = distance between teeth around the pitch circle.
// pressure_angle = The pressure angle of the gear.
// backlash = Add extra space to produce a total of 2*backlash between the two gears.
// Example(3D,Med,NoAxes,VPT=[-0.302111,3.7924,-9.252],VPR=[55,0,25],VPD=155.556): Non-parallel Helical Gears (without any profile shifting)
// circ_pitch=5; teeth1=15; teeth2=24; ha1=45; ha2=30; thick=10;
// d = gear_dist_skew(circ_pitch=circ_pitch, teeth1, teeth2, helical1=ha1, helical2=ha2);
// left(d/2) spur_gear(circ_pitch, teeth1, helical=ha1, thickness=thick, gear_spin=-90);
// right(d/2) xrot(ha1+ha2) spur_gear(circ_pitch, teeth2, helical=ha2, thickness=thick, gear_spin=90-180/teeth2);
function gear_dist_skew(teeth1,teeth2,helical1,helical2,profile_shift1,profile_shift2,pressure_angle=20, mod, circ_pitch, diam_pitch) =
function gear_dist_skew(teeth1,teeth2,helical1,helical2,profile_shift1,profile_shift2,pressure_angle=20,
mod, circ_pitch, diam_pitch, backlash=0) =
assert(all_nonnegative([teeth1,teeth2]),"Must give nonnegative values for teeth")
assert(teeth1>0 || teeth2>0, "One of the teeth counts must be nonzero")
let(
@ -3352,7 +3350,9 @@ function gear_dist_skew(teeth1,teeth2,helical1,helical2,profile_shift1,profile_s
pa_normal_eff = _working_normal_pressure_angle_skew(teeth1,profile_shift1,helical1,teeth2,profile_shift2,helical2,pressure_angle),
dist_adj = 0.5*(teeth1/cos(helical1)^3+teeth2/cos(helical2)^3)*(cos(pressure_angle)/cos(pa_normal_eff)-1)
)
mod*(teeth1/2/cos(helical1)+teeth2/2/cos(helical2)+dist_adj);
mod*(teeth1/2/cos(helical1)+teeth2/2/cos(helical2)+dist_adj)
+ backlash * (cos(helical1+helical2)) / tan(pressure_angle);
function _working_normal_pressure_angle_skew(teeth1,profile_shift1,helical1, teeth2, profile_shift2, helical2, pressure_angle) =
let(