Helical Gears Formula

Question 1

Normal Circular Pitch

Answer 1

Pcn= Pa sin φ= Pc cos φ= π/ Pdn

Where:
Pc= circular pitch
Pcn= normal circular pitch
Pa= axial pitch
Pc= circular pitch
φ= helix angle

Question 2

Normal Diameter Pitch

Answer 2

Pdn= π/ Pcn

Where:
Pdn= normal diametral pitch
Pcn= normal circular pitch

Question 3

Normal Pressure Angle

Answer 3

Øn= tan−1 φ cos φ

Where:
Øn= Normal pressure angle
Ø= pressure angle
φ= helix angle

Question 4

Axial Pitch

Answer 4

Pa= Pcn/ tan φ = π/ Pd tan φ

Where:
Pd= diametral pitch
Pcn= normal circular pitch
Pa= axial pitch
φ =helix angle

Question 5

Axial Force

Answer 5

Fa= Ft tan φ

Where:
Fa= axial load or force
Ft= tangential force
φ= helix angle

Question 6

Radial Force

Answer 6

Fr= Fn sin Ø

Where:
Fr= radial force
Fn= normal force
Ø= pressure angle

Question 7

Tangential Force

Answer 7

Ft= Fr/ tan Ø

Where:
Fr= radial force
Ft= tangential force
Ø= pressure angle

Question 8

Lead

Answer 8

L= np

Where:
L= lead
n= number of helix
P= pitch