Tính toán các thông số công nghệ bánh răng côn xoắn. Note (1) Addendum angle θ a is equivalent to Dedendum angle θ f of Mating gear. (2) Gear cutting by methods of Spread Blade and Single Side may use calculation formula from drawing. There are different calculations depending on gear cutting methods when using Gear tooth vernier calipers to calculate dimension of Sector span. Therefore designed Tooth thickness is necessary for reference. (3) Obtain Factor K from Fig. 2 of page 112
9.8 Calculation for Gleason system spiral bevel gear Number of teeth of pinion z1 z1 = Working depth Number of teeth of gear z2 z2 = Tooth depth Module m= Pressure angle h' = 1.700 m = h = 1.888m = α = (standard is 20°) Facewidth b= Shaft angle ¦ = 90° Gear terms Pinion Gear Reference diameter d = z 1m d = z 2m 10 Pitch angle δ = tan −1 z1 11 Cone distance Re = 12 Circular pitch p = π m = 3.14159m 13 Addendum ha1 = h' − 14 Dedendum h f = h − ha1 15 Bottom clearance c = h − h' (Parallel bottom clearance) 㧔ᐔⴕ㗂ߍ߈㧕⸶ᛮߌ 16 Dedendum angle(1) șf = tan −1 17 Tip angle δ a1 = δ + șf δ a = δ + șf 18 Root angle δ f = į1 − șf δ f = į − șf 19 Tip (Outside) diameter (heel) da1 = d + 2ha1cosį1 da = d + 2ha 2cosį 20 Pitch apex to crown X1 = 21 Tooth thickness(2) s1 = p − s 22 Backlash jn = Refer to Gleason Works for backlash recommendation or Backlash for Bevel gear in JIS B 1705 23 Spiral angle β = (35° is standard) z2 δ = 90° − δ d2 2sinδ hf1 Re d2 − ha1sinį1 = 0.460m + 0.390m Đ z2 ã ă â z1 h f = h − șf = tan −1 d1 − 2sinį 2 X2= s2 = hf Re p tanĮn − ( h a − ) − Km (3) cosβ 24 Shape of teeth 25 Driving gear 26 Revolving direction bcosįa1 cosșf Xb1 = 28 Tip (Inside) diameter (toe) di1 = da1 − 29 Material angle șx1 = 90° − șf șx = 90° − șf 30 Material angle șy1 = 90° − δ șy = 90° − δ 2bsinįa1 cosįf Xb = bcosįa cosșf 27 Axial facewidth di = da − 2bsinįa cosįf Note (1) Addendum angle θ a is equivalent to Dedendum angle θ f of Mating gear (2) Gear cutting by methods of Spread Blade and Single Side may use calculation formula from drawing There are different calculations depending on gear cutting methods when using Gear tooth vernier calipers to calculate dimension of Sector span Therefore designed Tooth thickness is necessary for reference (3) Obtain Factor K from Fig of page 112 115 K z1 z=15 z=16 z=17 z=20 z=25 z1 z2 Fig Tooth thickness factor K Fig Spiral angle for Spiral bevel gear (Mean spiral angle) Table Minimum number of teeth to prevent Undercut α =20° 116 α =16° No of teeth of pinion z1 z1 No of teeth of gear z2 z2 No of teeth of pinion z1 z1 No of teeth of gear z2 z2 α =14.5° No of teeth of No of teeth of pinion z1 gear z2 z1 z2 12 26 16 59 19 70 13 22 17 45 20 60 14 20 18 36 21 42 15 19 19 31 22 40 16 18 20 29 23 36 17 17 21 27 24 33 22 26 25 32 23 25 26 30 24 24 27 29 28 28