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Gears Shafts Right Angles Exact Helix Design Equations and Calculator

Machine Design and Engineering
Mechanical Gear Design and Engineering

Helical Gears Shafts at Right Angles Exact Design Equations and Calculator - Gears will have same direction of helix. Sum of the helix angles will equal 90 degrees.

Sum of helix angles of gear and pinion must equal 90 degrees.

Related:

Helical Gears Shafts Parallel Center Distance Exact Design Equations and Calculator
Helical Gears Shafts Parallel Center Distance Approximate Design Equations and Calculator
Helical Gears Shafts at Right Angles Approximate Design Equations and Calculator

 

Preview Helical Gears Shafts at Right Angles Exact Design Calculator

Design variables you should know:

• Position of gear having right- or left-hand helix depending on rotation and direction in which thrust is to be received,
• Pn = normal diametral pitch (pitch of cutter),
• R = ratio of number of teeth in large gear to number of teeth in small gear,
• α_a = approximate helix angle of large gear,
• C = exact center distance.

Number of teeth in pinion for any angle:

n = ( 2 C_a P_n sin α_a ) / ( 1 + R tan α_a )

Number of teeth in large gear formula:

N = n R

Exact helix angle of large gear ( exact angle found by trial and varying R sec α + cosec α )

α is the exact  helix angle of large gear found by trial from the following equality
R sec α + cosec α = R / cos α + 1 / sin α = ( 2 C P_n ) / n

Exact helix angle of small gear

β = 90° - α

Pitch diameter of large gear

D = N / ( P_n cos α )

Pitch diameter of small gear

d = n / ( P_n cos β )

Outside diameter of large gear

O = D + 2 / P_n

Outside diameter of small gear

o = d + 2 / P_n

Lead of helix on karge gear formula:

L = π D cot α

Lead of helix on small gear formula:

l = π d cot β 

Where:

C = approximate center distance (in, mm),
P_n  = normal diametral pitch (in, mm),
N = number of teeth in large gear,
n = number of teeth in small gear,
α = angle of gear helix (deg),
β = angle of pinion helix (deg),
R = ratio of gear to pinion,
L = lead of helix on large gear (in, mm),
l = lead of helix on pinion (in, mm).

References:

Machinerys Handbook, 29th Edition