741 lines
32 KiB
Python
741 lines
32 KiB
Python
#! /usr/bin/env python
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# -*- coding: utf-8 -*-
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""
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'''
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Copyright (C) 2007 Aaron Spike (aaron @ ekips.org)
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Copyright (C) 2007 Tavmjong Bah (tavmjong @ free.fr)
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Copyright (C) http://cnc-club.ru/forum/viewtopic.php?f=33&t=434&p=2594#p2500
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Copyright (C) 2014 Jürgen Weigert (juewei@fabmail.org)
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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2014-03-20 jw@suse.de 0.2 Option --accuracy=0 for automatic added.
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2014-03-21 sent upstream: https://bugs.launchpad.net/inkscape/+bug/1295641
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2014-03-21 jw@suse.de 0.3 Fixed center of rotation for gears with odd number of teeth.
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2014-04-04 juewei 0.7 Revamped calc_unit_factor().
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2014-04-05 juewei 0.7a Correctly positioned rack gear.
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The geometry above the meshing line is wrong.
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2014-04-06 juewei 0.7b Undercut detection added. Reference:
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http://nptel.ac.in/courses/IIT-MADRAS/Machine_Design_II/pdf/2_2.pdf
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Manually merged https://github.com/jnweiger/inkscape-gears-dev/pull/15
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2014-04-07 juewei 0.7c Manually merged https://github.com/jnweiger/inkscape-gears-dev/pull/17
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2014-04-09 juewei 0.8 Fixed https://github.com/jnweiger/inkscape-gears-dev/issues/19
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Ring gears are ready for production now. Thanks neon22 for driving this.
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Profile shift implemented (Advanced Tab), fixing
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https://github.com/jnweiger/inkscape-gears-dev/issues/9
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2015-05-29 juewei 0.9 ported to inkscape 0.91
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AttributeError: 'module' object inkex has no attribute 'uutounit
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Fixed https://github.com/jnweiger/inkscape-gears-dev
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'''
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from os import devnull # for debugging
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from math import pi, cos, sin, tan, radians, degrees, ceil, asin, acos, sqrt
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two_pi = 2 * pi
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import argparse
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from boxes.vectors import kerf, vdiff, vlength
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__version__ = '0.9'
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def linspace(a,b,n):
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""" return list of linear interp of a to b in n steps
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- if a and b are ints - you'll get an int result.
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- n must be an integer
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"""
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return [a+x*(b-a)/(n-1) for x in range(0,n)]
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def involute_intersect_angle(Rb, R):
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" "
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Rb, R = float(Rb), float(R)
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return (sqrt(R**2 - Rb**2) / (Rb)) - (acos(Rb / R))
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def point_on_circle(radius, angle):
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" return xy coord of the point at distance radius from origin at angle "
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x = radius * cos(angle)
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y = radius * sin(angle)
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return (x, y)
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### Undercut support functions
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def undercut_min_teeth(pitch_angle, k=1.0):
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"""
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computes the minimum tooth count for a
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spur gear so that no undercut with the given pitch_angle (in deg)
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and an addendum = k * metric_module, where 0 < k < 1
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Note:
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The return value should be rounded upwards for perfect safety. E.g.
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min_teeth = int(math.ceil(undercut_min_teeth(20.0))) # 18, not 17
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"""
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x = max(sin(radians(pitch_angle)), 0.01)
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return 2*k /(x*x)
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def undercut_max_k(teeth, pitch_angle=20.0):
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""" computes the maximum k value for a given teeth count and pitch_angle
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so that no undercut occurs.
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"""
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x = max(sin(radians(pitch_angle)), 0.01)
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return 0.5 * teeth * x * x
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def undercut_min_angle(teeth, k=1.0):
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""" computes the minimum pitch angle, to that the given teeth count (and
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profile shift) cause no undercut.
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"""
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return degrees(asin(min(0.856, sqrt(2.0*k/teeth)))) # max 59.9 deg
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def have_undercut(teeth, pitch_angle=20.0, k=1.0):
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""" returns true if the specified number of teeth would
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cause an undercut.
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"""
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return (teeth < undercut_min_teeth(pitch_angle, k))
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## gather all basic gear calculations in one place
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def gear_calculations(num_teeth, circular_pitch, pressure_angle, clearance=0, ring_gear=False, profile_shift=0.):
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""" Put base calcs for spur/ring gears in one place.
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- negative profile shifting helps against undercut.
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"""
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diametral_pitch = pi / circular_pitch
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pitch_diameter = num_teeth / diametral_pitch
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pitch_radius = pitch_diameter / 2.0
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addendum = 1 / diametral_pitch
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dedendum = addendum
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dedendum *= 1+profile_shift
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addendum *= 1-profile_shift
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if ring_gear:
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addendum = addendum + clearance # our method
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else:
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dedendum = dedendum + clearance # our method
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base_radius = pitch_diameter * cos(radians(pressure_angle)) / 2.0
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outer_radius = pitch_radius + addendum
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root_radius = pitch_radius - dedendum
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# Tooth thickness: Tooth width along pitch circle.
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tooth_thickness = ( pi * pitch_diameter ) / ( 2.0 * num_teeth )
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return (pitch_radius, base_radius,
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addendum, dedendum, outer_radius, root_radius,
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tooth_thickness
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)
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def generate_rack_points(tooth_count, pitch, addendum, pressure_angle,
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base_height, tab_length, clearance=0, draw_guides=False):
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""" Return path (suitable for svg) of the Rack gear.
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- rack gear uses straight sides
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- involute on a circle of infinite radius is a simple linear ramp
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- the meshing circle touches at y = 0,
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- the highest elevation of the teeth is at y = +addendum
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- the lowest elevation of the teeth is at y = -addendum-clearance
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- the base_height extends downwards from the lowest elevation.
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- we generate this middle tooth exactly centered on the y=0 line.
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(one extra tooth on the right hand side, if number of teeth is even)
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"""
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spacing = 0.5 * pitch # rolling one pitch distance on the spur gear pitch_diameter.
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# roughly center rack in drawing, exact position is so that it meshes
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# nicely with the spur gear.
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# -0.5*spacing has a gap in the center.
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# +0.5*spacing has a tooth in the center.
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if tab_length <= 0.0:
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tab_length = 1E-8
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tas = tan(radians(pressure_angle)) * addendum
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tasc = tan(radians(pressure_angle)) * (addendum+clearance)
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base_top = addendum+clearance
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base_bot = addendum+clearance+base_height
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x_lhs = -pitch * 0.5*tooth_count - tab_length
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# Start with base tab on LHS
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points = [] # make list of points
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points.append((x_lhs, base_bot))
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points.append((x_lhs, base_top))
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x = x_lhs + tab_length+tasc
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# An involute on a circle of infinite radius is a simple linear ramp.
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# We need to add curve at bottom and use clearance.
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for i in range(tooth_count):
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# move along path, generating the next 'tooth'
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# pitch line is at y=0. the left edge hits the pitch line at x
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points.append((x-tasc, base_top))
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points.append((x+tas, -addendum))
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points.append((x+spacing-tas, -addendum))
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points.append((x+spacing+tasc, base_top))
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x += pitch
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# add base on RHS
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x_rhs = x - tasc + tab_length
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points.append((x_rhs, base_top))
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points.append((x_rhs, base_bot))
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# We don't close the path here. Caller does it.
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# points.append((x_lhs, base_bot))
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# Draw line representing the pitch circle of infinite diameter
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guide_path = None
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p = []
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if draw_guides:
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p.append( (x_lhs + 0.5 * tab_length, 0) )
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p.append( (x_rhs - 0.5 * tab_length, 0) )
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return (points, p)
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def generate_spur_points(teeth, base_radius, pitch_radius, outer_radius, root_radius, accuracy_involute, accuracy_circular):
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""" given a set of core gear params
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- generate the svg path for the gear
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"""
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half_thick_angle = two_pi / (4.0 * teeth ) #?? = pi / (2.0 * teeth)
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pitch_to_base_angle = involute_intersect_angle( base_radius, pitch_radius )
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pitch_to_outer_angle = involute_intersect_angle( base_radius, outer_radius ) - pitch_to_base_angle
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start_involute_radius = max(base_radius, root_radius)
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radii = linspace(start_involute_radius, outer_radius, accuracy_involute)
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angles = [involute_intersect_angle(base_radius, r) for r in radii]
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centers = [(x * two_pi / float( teeth) ) for x in range( teeth ) ]
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points = []
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for c in centers:
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# Angles
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pitch1 = c - half_thick_angle
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base1 = pitch1 - pitch_to_base_angle
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offsetangles1 = [ base1 + x for x in angles]
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points1 = [ point_on_circle( radii[i], offsetangles1[i]) for i in range(0,len(radii)) ]
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pitch2 = c + half_thick_angle
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base2 = pitch2 + pitch_to_base_angle
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offsetangles2 = [ base2 - x for x in angles]
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points2 = [ point_on_circle( radii[i], offsetangles2[i]) for i in range(0,len(radii)) ]
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points_on_outer_radius = [ point_on_circle(outer_radius, x) for x in linspace(offsetangles1[-1], offsetangles2[-1], accuracy_circular) ]
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if root_radius > base_radius:
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pitch_to_root_angle = pitch_to_base_angle - involute_intersect_angle(base_radius, root_radius )
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root1 = pitch1 - pitch_to_root_angle
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root2 = pitch2 + pitch_to_root_angle
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points_on_root = [point_on_circle (root_radius, x) for x in linspace(root2, root1+(two_pi/float(teeth)), accuracy_circular) ]
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p_tmp = points1 + points_on_outer_radius[1:-1] + points2[::-1] + points_on_root[1:-1] # [::-1] reverses list; [1:-1] removes first and last element
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else:
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points_on_root = [point_on_circle (root_radius, x) for x in linspace(base2, base1+(two_pi/float(teeth)), accuracy_circular) ]
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p_tmp = points1 + points_on_outer_radius[1:-1] + points2[::-1] + points_on_root # [::-1] reverses list
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points.extend( p_tmp )
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return (points)
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def inkbool(val):
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return val not in ("False", False, "0", 0, "None", None)
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class OptionParser(argparse.ArgumentParser):
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types = {
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"int" : int,
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"float" : float,
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"string" : str,
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"inkbool" : inkbool,
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}
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def add_option(self, short, long_, **kw):
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kw["type"] = self.types[kw["type"]]
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names = []
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if short:
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names.append("-" + short.replace("-", "_")[1:])
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if long_:
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names.append("--" + long_.replace("-", "_")[2:])
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self.add_argument(*names, **kw)
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class Gears():
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def __init__(self, boxes, **kw):
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# an alternate way to get debug info:
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# could use inkex.debug(string) instead...
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try:
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self.tty = open("/dev/tty", 'w')
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except:
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self.tty = open(devnull, 'w') # '/dev/null' for POSIX, 'nul' for Windows.
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# print >>self.tty, "gears-dev " + __version__
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self.boxes = boxes
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self.OptionParser = OptionParser()
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self.OptionParser.add_option("-t", "--teeth",
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action="store", type="int",
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dest="teeth", default=24,
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help="Number of teeth")
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self.OptionParser.add_option("-s", "--system",
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action="store", type="string",
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dest="system", default='MM',
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help="Select system: 'CP' (Cyclic Pitch (default)), 'DP' (Diametral Pitch), 'MM' (Metric Module)")
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self.OptionParser.add_option("-d", "--dimension",
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action="store", type="float",
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dest="dimension", default=1.0,
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help="Tooth size, depending on system (which defaults to CP)")
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self.OptionParser.add_option("-a", "--angle",
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action="store", type="float",
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dest="angle", default=20.0,
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help="Pressure Angle (common values: 14.5, 20, 25 degrees)")
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self.OptionParser.add_option("-p", "--profile-shift",
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action="store", type="float",
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dest="profile_shift", default=20.0,
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help="Profile shift [in percent of the module]. Negative values help against undercut")
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self.OptionParser.add_option("-u", "--units",
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action="store", type="string",
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dest="units", default='mm',
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help="Units this dialog is using")
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self.OptionParser.add_option("-A", "--accuracy",
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action="store", type="int",
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dest="accuracy", default=0,
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help="Accuracy of involute: automatic: 5..20 (default), best: 20(default), medium 10, low: 5; good acuracy is important with a low tooth count")
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# Clearance: Radial distance between top of tooth on one gear to bottom of gap on another.
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self.OptionParser.add_option("", "--clearance",
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action="store", type="float",
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dest="clearance", default=0.0,
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help="Clearance between bottom of gap of this gear and top of tooth of another")
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self.OptionParser.add_option("", "--annotation",
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action="store", type="inkbool",
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dest="annotation", default=False,
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help="Draw annotation text")
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self.OptionParser.add_option("-i", "--internal-ring",
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action="store", type="inkbool",
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dest="internal_ring", default=False,
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help="Ring (or Internal) gear style (default: normal spur gear)")
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self.OptionParser.add_option("", "--mount-hole",
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action="store", type="float",
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dest="mount_hole", default=0.,
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help="Mount hole diameter")
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self.OptionParser.add_option("", "--mount-diameter",
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action="store", type="float",
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dest="mount_diameter", default=15,
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help="Mount support diameter")
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self.OptionParser.add_option("", "--spoke-count",
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action="store", type="int",
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dest="spoke_count", default=3,
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help="Spokes count")
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self.OptionParser.add_option("", "--spoke-width",
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action="store", type="float",
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dest="spoke_width", default=5,
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help="Spoke width")
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self.OptionParser.add_option("", "--holes-rounding",
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action="store", type="float",
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dest="holes_rounding", default=5,
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help="Holes rounding")
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self.OptionParser.add_option("", "--active-tab",
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action="store", type="string",
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dest="active_tab", default='',
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help="Active tab. Not used now.")
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self.OptionParser.add_option("-x", "--centercross",
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action="store", type="inkbool",
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dest="centercross", default=False,
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help="Draw cross in center")
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self.OptionParser.add_option("-c", "--pitchcircle",
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action="store", type="inkbool",
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dest="pitchcircle", default=False,
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help="Draw pitch circle (for mating)")
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self.OptionParser.add_option("-r", "--draw-rack",
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action="store", type="inkbool",
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dest="drawrack", default=False,
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help="Draw rack gear instead of spur gear")
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self.OptionParser.add_option("", "--rack-teeth-length",
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action="store", type="int",
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dest="teeth_length", default=12,
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help="Length (in teeth) of rack")
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self.OptionParser.add_option("", "--rack-base-height",
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action="store", type="float",
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dest="base_height", default=8,
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help="Height of base of rack")
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self.OptionParser.add_option("", "--rack-base-tab",
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action="store", type="float",
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dest="base_tab", default=14,
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help="Length of tabs on ends of rack")
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self.OptionParser.add_option("", "--undercut-alert",
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action="store", type="inkbool",
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dest="undercut_alert", default=False,
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help="Let the user confirm a warning dialog if undercut occurs. This dialog also shows helpful hints against undercut")
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def drawPoints(self, lines, kerfdir=1, close=True):
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if not lines:
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return
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if kerfdir != 0:
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lines = kerf(lines, self.boxes.burn*kerfdir, closed=close)
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self.boxes.ctx.save()
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self.boxes.ctx.move_to(*lines[0])
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for x, y in lines[1:]:
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self.boxes.ctx.line_to(x, y)
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if close:
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self.boxes.ctx.line_to(*lines[0])
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self.boxes.ctx.restore()
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def calc_circular_pitch(self):
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""" We use math based on circular pitch.
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"""
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dimension = self.options.dimension
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if self.options.system == 'CP': # circular pitch
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circular_pitch = dimension * 25.4
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elif self.options.system == 'DP': # diametral pitch
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circular_pitch = pi * 25.4 / dimension
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elif self.options.system == 'MM': # module (metric)
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circular_pitch = pi * dimension
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else:
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raise ValueError("unknown system '%s', try CP, DP, MM" % self.options.system)
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# circular_pitch defines the size in mm
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return circular_pitch
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def generate_spokes(self, root_radius, spoke_width, spokes, mount_radius, mount_hole,
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unit_factor, unit_label):
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""" given a set of constraints
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- generate the svg path for the gear spokes
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- lies between mount_radius (inner hole) and root_radius (bottom of the teeth)
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- spoke width also defines the spacing at the root_radius
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- mount_radius is adjusted so that spokes fit if there is room
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- if no room (collision) then spokes not drawn
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"""
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if not spokes:
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return []
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# Spokes
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collision = False # assume we draw spokes
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messages = [] # messages to send back about changes.
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spoke_holes = []
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r_outer = root_radius - spoke_width
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try:
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spoke_count = spokes
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spokes = [i*2*pi/spokes for i in range(spoke_count)]
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except TypeError:
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spoke_count = len(spokes)
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spokes = [radians(a) for a in spokes]
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spokes.append(spokes[0]+two_pi)
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|
|
# checks for collision with spokes
|
|
# check for mount hole collision with inner spokes
|
|
if mount_radius <= mount_hole/2:
|
|
adj_factor = (r_outer - mount_hole/2) / 5
|
|
|
|
if adj_factor < 0.1:
|
|
# not enough reasonable room
|
|
collision = True
|
|
else:
|
|
mount_radius = mount_hole/2 + adj_factor # small fix
|
|
messages.append("Mount support too small. Auto increased to %2.2f%s." % (mount_radius/unit_factor*2, unit_label))
|
|
|
|
# then check to see if cross-over on spoke width
|
|
for i in range(spoke_count):
|
|
angle = spokes[i]-spokes[i-1]
|
|
|
|
if spoke_width >= angle * mount_radius:
|
|
adj_factor = 1.2 # wrong value. its probably one of the points distances calculated below
|
|
mount_radius += adj_factor
|
|
messages.append("Too many spokes. Increased Mount support by %2.3f%s" % (adj_factor/unit_factor, unit_label))
|
|
|
|
# check for collision with outer rim
|
|
if r_outer <= mount_radius:
|
|
# not enough room to draw spokes so cancel
|
|
collision = True
|
|
if collision: # don't draw spokes if no room.
|
|
messages.append("Not enough room for Spokes. Decrease Spoke width.")
|
|
else: # draw spokes
|
|
|
|
for i in range(spoke_count):
|
|
self.boxes.ctx.save()
|
|
start_a, end_a = spokes[i], spokes[i+1]
|
|
# inner circle around mount
|
|
asin_factor = spoke_width/mount_radius/2
|
|
# check if need to clamp radius
|
|
asin_factor = max(-1.0, min(1.0, asin_factor)) # no longer needed - resized above
|
|
a = asin(asin_factor)
|
|
|
|
# is inner circle too small
|
|
asin_factor = spoke_width/r_outer/2
|
|
# check if need to clamp radius
|
|
asin_factor = max(-1.0, min(1.0, asin_factor)) # no longer needed - resized above
|
|
a2 = asin(asin_factor)
|
|
l = vlength(vdiff(point_on_circle(mount_radius, start_a + a),
|
|
point_on_circle(r_outer, start_a + a2)))
|
|
self.boxes.moveTo(*point_on_circle(mount_radius, start_a + a), degrees=degrees(start_a))
|
|
self.boxes.polyline(
|
|
l,
|
|
+90+degrees(a2), 0,
|
|
(degrees(end_a-start_a-2*a2), r_outer), 0,
|
|
+90+degrees(a2),
|
|
l, 90-degrees(a), 0,
|
|
(-degrees(end_a-start_a-2*a), mount_radius),
|
|
0, 90+degrees(a2), 0
|
|
)
|
|
|
|
self.boxes.ctx.restore()
|
|
|
|
return messages
|
|
|
|
def sizes(self, **kw):
|
|
self.options = self.OptionParser.parse_args(["--%s=%s" % (name,value) for name, value in kw.items()])
|
|
# Pitch (circular pitch): Length of the arc from one tooth to the next)
|
|
# Pitch diameter: Diameter of pitch circle.
|
|
pitch = self.calc_circular_pitch()
|
|
|
|
if self.options.drawrack:
|
|
base_height = self.options.base_height * unit_factor
|
|
tab_width = self.options.base_tab * unit_factor
|
|
tooth_count = self.options.teeth_length
|
|
width = tooth_count * pitch + 2*tab_width
|
|
height = base_height+ 2* addendum
|
|
return 0, width, height
|
|
|
|
teeth = self.options.teeth
|
|
# Angle of tangent to tooth at circular pitch wrt radial line.
|
|
angle = self.options.angle
|
|
# Clearance: Radial distance between top of tooth on one gear to
|
|
# bottom of gap on another.
|
|
clearance = self.options.clearance # * unit_factor
|
|
# Replace section below with this call to get the combined gear_calculations() above
|
|
(pitch_radius, base_radius, addendum, dedendum,
|
|
outer_radius, root_radius, tooth) = gear_calculations(teeth, pitch, angle, clearance, self.options.internal_ring, self.options.profile_shift*0.01)
|
|
if self.options.internal_ring:
|
|
outer_radius += self.options.spoke_width
|
|
return pitch_radius, 2*outer_radius, 2*outer_radius
|
|
|
|
def gearCarrier(self, r, spoke_width, positions, mount_radius, mount_hole, circle=True, callback=None, move=None):
|
|
width = 2*r+spoke_width
|
|
|
|
if self.boxes.move(width, width, move, before=True):
|
|
return
|
|
|
|
try:
|
|
positions = [i*360/positions for i in range(positions)]
|
|
except TypeError:
|
|
pass
|
|
|
|
self.boxes.ctx.save()
|
|
self.boxes.moveTo(width/2.0, width/2.0)
|
|
if callback:
|
|
self.boxes.cc(callback, None)
|
|
self.generate_spokes(r+0.5*spoke_width, spoke_width, positions, mount_radius, mount_hole, 1, "")
|
|
self.boxes.hole(0, 0, mount_hole)
|
|
|
|
for angle in positions:
|
|
self.boxes.ctx.save()
|
|
self.boxes.moveTo(0, 0, angle)
|
|
self.boxes.hole(r, 0, mount_hole)
|
|
self.boxes.ctx.restore()
|
|
|
|
self.boxes.moveTo(r+0.5*spoke_width+self.boxes.burn, 0, 90)
|
|
self.boxes.corner(360, r+0.5*spoke_width)
|
|
|
|
self.boxes.ctx.restore()
|
|
self.boxes.move(width, width, move)
|
|
|
|
def __call__(self, teeth_only=False, move="", callback=None, **kw):
|
|
""" Calculate Gear factors from inputs.
|
|
- Make list of radii, angles, and centers for each tooth and
|
|
iterate through them
|
|
- Turn on other visual features e.g. cross, rack, annotations, etc
|
|
"""
|
|
self.options = self.OptionParser.parse_args(["--%s=%s" % (name,value) for name, value in kw.items()])
|
|
|
|
warnings = [] # list of extra messages to be shown in annotations
|
|
# calculate unit factor for units defined in dialog.
|
|
unit_factor = 1
|
|
# User defined options
|
|
teeth = self.options.teeth
|
|
# Angle of tangent to tooth at circular pitch wrt radial line.
|
|
angle = self.options.angle
|
|
# Clearance: Radial distance between top of tooth on one gear to
|
|
# bottom of gap on another.
|
|
clearance = self.options.clearance * unit_factor
|
|
mount_hole = self.options.mount_hole * unit_factor
|
|
# for spokes
|
|
mount_radius = self.options.mount_diameter * 0.5 * unit_factor
|
|
spoke_count = self.options.spoke_count
|
|
spoke_width = self.options.spoke_width * unit_factor
|
|
holes_rounding = self.options.holes_rounding * unit_factor # unused
|
|
# visible guide lines
|
|
centercross = self.options.centercross # draw center or not (boolean)
|
|
pitchcircle = self.options.pitchcircle # draw pitch circle or not (boolean)
|
|
|
|
# Accuracy of teeth curves
|
|
accuracy_involute = 20 # Number of points of the involute curve
|
|
accuracy_circular = 9 # Number of points on circular parts
|
|
if self.options.accuracy is not None:
|
|
if self.options.accuracy == 0:
|
|
# automatic
|
|
if teeth < 10: accuracy_involute = 20
|
|
elif teeth < 30: accuracy_involute = 12
|
|
else: accuracy_involute = 6
|
|
else:
|
|
accuracy_involute = self.options.accuracy
|
|
|
|
accuracy_circular = max(3, int(accuracy_involute/2) - 1) # never less than three
|
|
# print >>self.tty, "accuracy_circular=%s accuracy_involute=%s" % (accuracy_circular, accuracy_involute)
|
|
# Pitch (circular pitch): Length of the arc from one tooth to the next)
|
|
# Pitch diameter: Diameter of pitch circle.
|
|
pitch = self.calc_circular_pitch()
|
|
# Replace section below with this call to get the combined gear_calculations() above
|
|
(pitch_radius, base_radius, addendum, dedendum,
|
|
outer_radius, root_radius, tooth) = gear_calculations(teeth, pitch, angle, clearance, self.options.internal_ring, self.options.profile_shift*0.01)
|
|
|
|
b = self.boxes.burn
|
|
# Add Rack (instead)
|
|
if self.options.drawrack:
|
|
base_height = self.options.base_height * unit_factor
|
|
tab_width = self.options.base_tab * unit_factor
|
|
tooth_count = self.options.teeth_length
|
|
(points, guide_points) = generate_rack_points(tooth_count, pitch, addendum, angle,
|
|
base_height, tab_width, clearance, pitchcircle)
|
|
width = tooth_count * pitch + 2 * tab_width
|
|
height = base_height + 2 * addendum
|
|
if self.boxes.move(width, height, move, before=True):
|
|
return
|
|
|
|
self.boxes.cc(callback, None)
|
|
self.boxes.moveTo(width/2.0, base_height+addendum, -180)
|
|
if base_height < 0:
|
|
points = points[1:-1]
|
|
self.drawPoints(points, close=base_height >= 0)
|
|
self.drawPoints(guide_points, kerfdir=0)
|
|
self.boxes.move(width, height, move)
|
|
|
|
return
|
|
|
|
# Move only
|
|
width = height = 2 * outer_radius
|
|
if self.options.internal_ring:
|
|
width = height = width + 2 * self.options.spoke_width
|
|
|
|
if not teeth_only and self.boxes.move(width, height, move, before=True):
|
|
return
|
|
|
|
# Detect Undercut of teeth
|
|
## undercut = int(ceil(undercut_min_teeth( angle )))
|
|
## needs_undercut = teeth < undercut #? no longer needed ?
|
|
if have_undercut(teeth, angle, 1.0):
|
|
min_teeth = int(ceil(undercut_min_teeth(angle, 1.0)))
|
|
min_angle = undercut_min_angle(teeth, 1.0) + .1
|
|
max_k = undercut_max_k(teeth, angle)
|
|
msg = "Undercut Warning: This gear (%d teeth) will not work well.\nTry tooth count of %d or more,\nor a pressure angle of %.1f [deg] or more,\nor try a profile shift of %d %%.\nOr other decent combinations." % (teeth, min_teeth, min_angle, int(100.*max_k)-100.)
|
|
# alas annotation cannot handle the degree symbol. Also it ignore newlines.
|
|
# so split and make a list
|
|
warnings.extend(msg.split("\n"))
|
|
|
|
# All base calcs done. Start building gear
|
|
points = generate_spur_points(teeth, base_radius, pitch_radius, outer_radius, root_radius, accuracy_involute, accuracy_circular)
|
|
|
|
if not teeth_only:
|
|
self.boxes.moveTo(width/2, height/2)
|
|
self.boxes.cc(callback, None, 0, 0)
|
|
self.drawPoints(points)
|
|
# Spokes
|
|
if not teeth_only and not self.options.internal_ring: # only draw internals if spur gear
|
|
msg = self.generate_spokes(root_radius, spoke_width, spoke_count, mount_radius, mount_hole,
|
|
unit_factor, self.options.units)
|
|
warnings.extend(msg)
|
|
|
|
# Draw mount hole
|
|
# A : rx,ry x-axis-rotation, large-arch-flag, sweepflag x,y
|
|
r = mount_hole / 2
|
|
self.boxes.hole(0, 0, r)
|
|
elif not teeth_only:
|
|
# its a ring gear
|
|
# which only has an outer ring where width = spoke width
|
|
r = outer_radius + spoke_width + self.boxes.burn
|
|
self.boxes.ctx.save()
|
|
self.boxes.moveTo(r, 0)
|
|
self.boxes.ctx.arc(-r, 0, r, 0, 2*pi)
|
|
self.boxes.ctx.restore()
|
|
|
|
# Add center
|
|
if centercross:
|
|
cs = pitch / 3.0 # centercross length
|
|
self.boxes.ctx.save()
|
|
self.boxes.ctx.move_to(-cs, 0)
|
|
self.boxes.ctx.line_to(+cs, 0)
|
|
self.boxes.ctx.move_to(0, -cs)
|
|
self.boxes.ctx.line_to(0, +cs)
|
|
self.boxes.ctx.restore()
|
|
|
|
# Add pitch circle (for mating)
|
|
if pitchcircle:
|
|
self.boxes.hole(0, 0, pitch_radius)
|
|
|
|
# Add Annotations (above)
|
|
if self.options.annotation:
|
|
outer_dia = outer_radius * 2
|
|
|
|
if self.options.internal_ring:
|
|
outer_dia += 2 * spoke_width
|
|
|
|
notes = []
|
|
notes.extend(warnings)
|
|
#notes.append('Document (%s) scale conversion = %2.4f' % (self.document.getroot().find(inkex.addNS('namedview', 'sodipodi')).get(inkex.addNS('document-units', 'inkscape')), unit_factor))
|
|
notes.extend(['Teeth: %d CP: %2.4f(%s) ' % (teeth, pitch / unit_factor, self.options.units),
|
|
'DP: %2.3f Module: %2.4f(mm)' % (25.4 * pi / pitch, pitch),
|
|
'Pressure Angle: %2.2f degrees' % (angle),
|
|
'Pitch diameter: %2.3f %s' % (pitch_radius * 2 / unit_factor, self.options.units),
|
|
'Outer diameter: %2.3f %s' % (outer_dia / unit_factor, self.options.units),
|
|
'Base diameter: %2.3f %s' % (base_radius * 2 / unit_factor, self.options.units)#,
|
|
#'Addendum: %2.4f %s' % (addendum / unit_factor, self.options.units),
|
|
#'Dedendum: %2.4f %s' % (dedendum / unit_factor, self.options.units)
|
|
])
|
|
# text height relative to gear size.
|
|
# ranges from 10 to 22 over outer radius size 60 to 360
|
|
text_height = max(10, min(10+(outer_dia-60)/24, 22))
|
|
# position above
|
|
y = - outer_radius - (len(notes)+1) * text_height * 1.2
|
|
|
|
for note in notes:
|
|
self.boxes.text(note, -outer_radius, y)
|
|
y += text_height * 1.2
|
|
|
|
if not teeth_only:
|
|
self.boxes.move(width, height, move)
|
|
|
|
if __name__ == '__main__':
|
|
e = Gears()
|
|
e.affect()
|
|
|
|
# Notes
|
|
|