Force Analysis in Helical Gears:

A helical gear can be left handed or right handed. Figure 3(a) illustrated a left handed helical gear. It might be a driver or driven gear. Let us consider that this is a driver gear. The normal force on the tooth F₃₂ may be resulted in three components as radial tangential, and axial. It can be supposed to be acting along with the diagonal of a parallalopiped. The parallelopiped is illustrated by dotted lines along one corner at the pitch point. It is illustrated enlarged in Figure 3(b). The normal reaction on the tooth F₃₂ has been illustrated along the diagonal EP. The angle EPF is equivalent to the pressure angle 'φ' & ∠ GPF in the horizontal plane shall be equivalent to the helix angle 'ψ'. The components will be along the lines GP, CP and AP, respectively. Initially force 'F₃₂' can be resolved in the vertical plane passing by the lines FP & CP.

(i)                                               (ii)

Figure 3 : Helical Gear Forces

Hence, the radial component

                                                                       . . . (4)

Here φ is normal helix angle.

  ∠GPF = Helix angle ' ψ '

Hence, the tangential component is given by following

                                . . . (5)

 The axial component is given by following

                     . . . (6)

As explained in the last section, the tangential component may be estimated from driving torque and tooth load may be measured from it. So,

                                   . . . (7)

           . . . (8)

and

                                     . . . ( 9)