Helical Gears

Summary

Here, the gear teeth are at an angle which make them quieter and stronger

You can have right vs left-handed gears which are mated with opposite handedness. For right handed hears, the teeth twist clockwise.

Some other properties

• Teeth are not parallel to axis
• Reduced backlash
• Expensive
• Quite
• Tangential and axial forces due to helical shape of gears
• Parallel or crossed axes
• Strong tooth sections
• Harder to disengage

Configuration of Angles

• $\psi$ = the helical angle
• $p_t$ = transverse circular angle
• $p_n$ = normal circular pitch
• ${\varphi }_t$ = transverse pressure angle
• ${\varphi }_n$ = normal pressure angle

Using these definitions…

• $p_n=p_t\cos \psi$
• $\cos \psi =\frac{\tan {\varphi }_n}{\tan {\varphi }_t}$

Some properties from the configuration of loads…
Front View

• $W_r=W_t\tan \left({\varphi }_t\right)$
• $W_r=W_t\tan \left({\varphi }_t\right)$ Top View
• $W_r=W_t\tan \left({\varphi }_t\right)$
• $W_x=W_t\tan \psi$ Normal Plane
• $W_r=W_t\tan {\varphi }_t$
• $W_x=W_t\tan \psi$
• $W_r=W_n\sin {\varphi }_n$
• $\tan {\varphi }_n=\tan {\varphi }_t\cos \psi$
• $W_r=W_n\sin {\varphi }_n$