Equation Driven Involute Curve Spur Gear Tooth Form in Solidworks

grabcad

This is one that has a TRUE involute tooth form driven by an equation. It seems to be a stable template. It may “break” if an input value is beyond what it can calculate. BUT if it does break just change the value to something that is “in range” or a value that it can calculate. Perhaps the tip rad or the root rad is too big. Or the number of teeth too small. Or the Pressure angle is too large. Play with the values until you get what you want. Note: the template is set for the User input of the following Global Variables in Solidworks: "PD"= 2.932 * 2 --- Pitch Diameter "PA"= 20 --- Pressure Angle "N"= 30 --- Number of Teeth "TipR"= .05 --- Tip Radius "RootR"= .02 --- Root Radius User can also change: "a"= 1 / "DP" --- Addendum "b"= 1.25 / "DP" --- Dedendum by changing the "1" or the "1.25" The following are calculated: "AngleA"= 360 / ( "N" * 2 ) --- AngleA "AngleB"= "AngleA" / 2 --- AngleB "DP"= "N" / "PD" --- Diametrical Pitch "OD"= "PD" + ( 2 * "a" ) --- Outside Diameter "DR"= ( "PD" / 2 ) - "b" --- Dedendum Radius "AngleC"= "D2@SketchICL" --- AngleC Sketch Dimensions from Global Variables: "ArcLen@SketchICL"= "TanLen@SketchICL" "D1@CirPattern9"= "N" --- Number of Teeth "D1@Fillet2"= "RootR" --- Root Radus "D1@Fillet1"= "TipR" --- Tip Radus The definition in the parameters of the parametric “equation driven curve” for the involute form: Xt = ("D1@SketchICL"/2) * (cos(t) + t*sin(t)) Xy = ("D1@SketchICL"/2) * (sin(t) - t*cos(t)) t1 = 0 t2 = 1 Note: I made this so I can use a gear for a given Pitch diameter and number of teeth. (For those values are what is critical to the design I use these gears in.) Also Note: A “Non-Standard” Pressure Angle can be used, for I EDM the profiles. A standard PA can be input and it will be just fine. (But I can change it to whatever works/looks good, therefore I have no need to adhere to a standard pressure angle due to standard cutters) Note: This gear is set for the user inputs of the pitch diameter, number of teeth & pressure angle. Which limits the ratios that can be utilized. For teeth of mating gears need to have the same tooth width and only certian combinations or ratios allow this 1:1, 1:2 ...(for given tooth count & pitch diameters) This model could be modified to be a gear template that has the user input of the Diametrical Pitch and Number of Teeth to determine the Pitch Diameter --- "PD"= "N" / "DP"