Robust Involute Helical Gear Generator

grabcad

For modeling a TRUE Involute Spur Gear in Solidworks This template is built with some "IF" "THEN" statements So it can handle a wider range of user inputs for " Number of Teeth. This is with the Gullet of the first tooth cut on the "Y" axis Note: this template is set for the User input of the following: "Diametrical Pitch" "Number of Teeth" "Pressure Angle" "Gear Thickness" Note: I could NOT make the parameter for the Pitch in the feature "Helix-DCGTBC" or the "Helix-DCLTBC" be equal to a "GLOBAL VARIABLE" Thus they have to be "edited in place" or in that feature so to speak. Also Note: The only difference between the CW & the CCW gears is the parameter choice in the feature "Helix-DCGTBC" and "Helix-DCLTBC" GLOBAL VARIABLES "DiametralPitch"= 25.4 'Diametral Pitch "NumTeeth"= 40 'Number of Teeth "PressureAngle"= 15deg 'Pressure Angle "Gear Thichness"= .5 'Gear Thickness "Addendum"= 1 / "DiametralPitch" 'Addendum "Dedendum"= 1.25 / "DiametralPitch" 'Dedendum "WorkingDepth"= 2 / " DiametralPitch"'Working Depth - here for REF (Not used in building model) "WholeDepth"= 2.25 / "DiametralPitch" 'Whole Depth - here for REF (Not used in building model) "Clearance"= .25 / "DiametralPitch" 'Clearance "CircularPitch"= pi / "DiametralPitch" 'Circular Pitch - here for REF (Not used in building model) "PitchCircle"= "NumTeeth" / "DiametralPitch" 'Pitch Circle - or - Pitch Diameter "OutsideDiameter"= ( "NumTeeth" + 2 ) / "DiametralPitch" 'Outside Diameter "Fillet_Root"= "Clearance" * cos ( "PressureAngle" ) * tan ( ( 90 + "PressureAngle" ) / 2 ) 'Fillet Root "AddendumCircle"= "PitchCircle" + ( 2 * "Addendum" ) 'Addendum Circle - or - Addendum Diameter "DedendumCircle"= "PitchCircle" - ( 2 * "Dedendum" ) 'Dedendum Circle - or - Dedendum Diameter "BaseCircle"= "PitchCircle" * cos ( "PressureAngle" ) 'Base Circle - Base Diameter "PitchAngle"= 360deg / "NumTeeth" 'Pitch Angle "Alpha"= sqr ( "PitchCircle" ^ 2 - "BaseCircle" ^ 2 ) / "BaseCircle" * 180 / PI - "PressureAngle" 'Alpha - Used for Calculating Beta "Beta"= ( "PitchAngle" / 4 - ( "Alpha" - 90 ) ) 'Beta - Used in definition of the parameters for the parametric equation driven curve "Gamma"= ( "PitchAngle" / 4 - ( "Alpha" + 90 ) ) 'Gamma - Used in definition of the parameters for the parametric equation driven curve "Phi"= sqr ( ( "AddendumCircle" / 2 ) ^ 2 - ( "BaseCircle" / 2 ) ^ 2 ) / ( "BaseCircle" / 2 ) 'Phi - Used in definition of the parameters for the parametric equation driven curve FEATURES "Helix-Sketch-DCGTBC"= iif ( "DedendumCircle" > "BaseCircle" , "unsuppressed" , "suppressed" ) 'if Dedendum Circle IS GREATER THAN "BaseCircle" THEN UnsuppressORSuppress FEATURE "Helix-Sketch-DCLTBC"= iif ( "DedendumCircle" - .002 > "BaseCircle" , "suppressed" , "unsuppressed" ) 'if Dedendum Circle - .002 IS GREATER THAN "BaseCircle" THEN SuppressORUnsuppress FEATURE "Helix-DCGTBC"= iif ( "DedendumCircle" > "BaseCircle" , "unsuppressed" , "suppressed" ) 'if Dedendum Circle IS GREATER THAN "BaseCircle" THEN UnsuppressORSuppress FEATURE "Helix-DCLTBC"= iif ( "DedendumCircle" - .002 > "BaseCircle" , "suppressed" , "unsuppressed" ) 'if Dedendum Circle - .002 IS GREATER THAN "BaseCircle" THEN SuppressORUnsuppress FEATURE "DCGTBC"= iif ( "DedendumCircle" > "BaseCircle" , "unsuppressed" , "suppressed" ) 'if Dedendum Circle IS GREATER THAN BaseCircle THEN UnsuppressORSuppress FEATURE "DCLTBC"= iif ( "DedendumCircle" - .002 > "BaseCircle" , "suppressed" , "unsuppressed" ) 'if Dedendum Circle - .002 IS GREATER THAN BaseCircle THEN SuppressORUnsuppress FEATURE "Cut-Extrude-DCGTBC"= iif ( "DedendumCircle" > "BaseCircle" , "unsuppressed" , "suppressed" ) 'if Dedendum Circle IS GREATER THAN BaseCircle THEN UnsuppressORSuppress FEATURE "Cut-Extrude-DCLTBC"= iif ( "DedendumCircle" - .002 > "BaseCircle" , "suppressed" , "unsuppressed" ) 'if Dedendum Circle - .002 IS GREATER THAN BaseCircle THEN SuppressORUnsuppress FEATURE "Fillet-Tip-DCGTBC"= iif ( "DedendumCircle" > "BaseCircle" , "unsuppressed" , "suppressed" ) 'if Dedendum Circle IS GREATER THAN "BaseCircle" THEN UnsuppressORSuppress FEATURE "Fillet-Tip-DCLTBC"= iif ( "DedendumCircle" - .002 > "BaseCircle" , "suppressed" , "unsuppressed" ) 'if Dedendum Circle - .002 IS GREATER THAN "BaseCircle" THEN SuppressORUnsuppress FEATURE "Fillet-Root-DCLTBC"= iif ( "DedendumCircle" - .002 > "BaseCircle" , "suppressed" , "unsuppressed" ) 'if Dedendum Circle - .002 IS GREATER THAN "BaseCircle" THEN SuppressORUnsuppress FEATURE "CirPattern-DCGTBC"= iif ( "DedendumCircle" > "BaseCircle" , "unsuppressed" , "suppressed" ) 'if Dedendum Circle IS GREATER THAN BaseCircle THEN UnsuppressORSuppress FEATURE "CirPattern-DCLTBC"= iif ( "DedendumCircle" - .002 > "BaseCircle" , "suppressed" , "unsuppressed" ) 'if Dedendum Circle - .002 IS GREATER THAN BaseCircle THEN SuppressORUnsuppress FEATURE EQUATIONS "D1@Boss-Extrude1"="Gear Thichness" "D1@Fillet-Tip-DCLTBC"="Fillet_Root"/2 "D1@Fillet-Root-DCLTBC"="Fillet_Root" "D1@CirPattern-DCLTBC"="NumTeeth" "D1@Fillet-Tip-DCGTBC"="Fillet_Root"/2 "D1@CirPattern-DCGTBC"="NumTeeth" The definition in the parameters of the parametric “equation driven curve” for the involute form (first involute): Xt = ("BaseCircle"/2) * (cos(t + "Beta"*pi/180) + t*sin(t + "beta"*pi/180)) Yt = ("BaseCircle"/2) * (sin(t + "Beta"*pi/180) - t*cos(t + "beta"*pi/180)) t1 = 0 t2 = "phi" The definition in the parameters of the parametric “equation driven curve” for the involute form (second involute): Xt = ("BaseCircle"/2) * (cos(-t - "Gamma"*pi/180) - t*sin(-t - "Gamma"*pi/180)) Yt = ("BaseCircle"/2) * (sin(-t - "Gamma"*pi/180) + t*cos(-t - "Gamma"*pi/180)) t1 = 0 t2 = "phi"