Commit 3219ff71 authored by Julian Stirling's avatar Julian Stirling 🐧
Browse files

Merge branch 'gear-ratios' into 'master' 

Move gear ratio error message

See merge request !552
parents 3d05704e f4515035

openscad/large_gears.scad

+7 −4
Original line number Diff line number Diff line
@@ -15,8 +15,11 @@ use <./libs/utilities.scad> 


// The ratio is the ratio between the 'large' gear on the actuator and the 'small' gear on the motor.

// This means that it is a gearing down ratio.

// The standard ratio is 2. The total number of teeth on both gears is 36, which is defined by the distance between the rotation axes.

// For an integer number of teeth, allowed ratios are of the form n/(36-n). Ratios from 0.8 (16/20, 1:1.25) to 2 (24/12, 1:0.5) are expected to fit in the body

// The standard ratio is 2. The total number of teeth on both gears is 36, which gives

// reasonable size teeth given the distance between the rotation axes.



// For an integer number of teeth, allowed ratios are of the form n/(36-n).

// Ratios from 0.8 (16/20, 1:1.25) to 2 (24/12, 1:0.5) are expected to fit in the body.



// Gearing ratio for x and y axes. Ratio for z axis fixed at 2

RATIO = 2;
@@ -24,10 +27,10 @@ RATIO = 2; 
printable_large_gears(ratio=RATIO);



module printable_large_gears(ratio=2){

    // check the ratio gives an integer number of teeth

    assert(floor(n_teeth_large_gear(ratio))==n_teeth_large_gear(ratio),"The number of teeth on the large gear is not integer");

    // Calculate the spacing from the gear pitch radius.

    // Add 4mm of clearance

    // Note: This will throw an error if either the ratio, or a ratio of 2, 

    // gives a non-integer number of gear teeth

    spacing = large_gear_pitch_radius(ratio) + large_gear_pitch_radius(ratio=2) + 4;

    // x and y gears

    repeat([0,2*spacing,0],2,center=true){

openscad/libs/gears.scad

+10 −2
Original line number Diff line number Diff line
@@ -33,10 +33,18 @@ function total_gear_teeth() = 36; 




/* Number of teeth on the small gear*/

function n_teeth_small_gear(ratio=2) = total_gear_teeth() / (ratio + 1);

function n_teeth_small_gear(ratio=2) =

    let ( n_teeth_s = total_gear_teeth() / (ratio + 1) )

    // check the ratio gives an integer number of teeth

    assert(floor(n_teeth_s)==n_teeth_s,"The number of teeth on each gear is not integer")

    n_teeth_s;



/* Number of teeth on the large gear*/

function n_teeth_large_gear(ratio=2) = n_teeth_small_gear(ratio) * ratio;

function n_teeth_large_gear(ratio=2) =

    let ( n_teeth_l = n_teeth_small_gear(ratio) * ratio )

    // check the ratio gives an integer number of teeth

    assert(floor(n_teeth_l)==n_teeth_l,"The number of teeth on each gear is not integer")

    n_teeth_l;



/* Distance from the centre of the small gear to the centre of the large gear*/

function gear_c2c_distance() = 20;

openscad/small_gears.scad

+7 −4
Original line number Diff line number Diff line
@@ -14,8 +14,11 @@ use <./libs/utilities.scad> 


// The ratio is the ratio between the 'large' gear on the actuator and the 'small' gear on the motor.

// This means that it is a gearing down ratio.

// The standard ratio is 2. The total number of teeth on both gears is 36, which is defined by the distance between the rotation axes.

// For an integer number of teeth, allowed ratios are of the form n/(36-n). Ratios from 0.8 (16/20, 1:1.25) to 2 (24/12, 1:0.5) are expected to fit in the body

// The standard ratio is 2. The total number of teeth on both gears is 36, which gives

// reasonable size teeth given the distance between the rotation axes.



// For an integer number of teeth, allowed ratios are of the form n/(36-n).

// Ratios from 0.8 (16/20, 1:1.25) to 2 (24/12, 1:0.5) are expected to fit in the body.



// Gearing ratio for x and y axes. Ratio for z axis fixed at 2

RATIO = 2;
@@ -23,10 +26,10 @@ RATIO = 2; 
printable_small_gears(ratio=RATIO);



module printable_small_gears(ratio=2){

    // check the ratio gives an integer number of teeth

    assert(floor(n_teeth_small_gear(ratio))==n_teeth_small_gear(ratio),"The number of teeth on the small gear is not integer");

    // Calculate the spacing from the gear pitch radius.

    // Add 4mm of clearance

    // Note: This will throw an error if either the ratio, or a ratio of 2, 

    // gives a non-integer number of gear teeth

    spacing = small_gear_pitch_radius(ratio) + small_gear_pitch_radius(ratio=2) + 4;

    // x and y gears

    repeat([0, 2*spacing, 0], 2, center=true){