In this video, we look at the geometry of involute gears. We take a closer look at the various parameters such as module, standard reference pitch circle diameter, operating pitch circle diameter, circular pitch, meshing pitch, etc. The involute is created by rolling a straight line on a base circle. The resulting tooth shape leads to favorable meshing conditions when two gears engage.
00:00 Use of involute gears
00:27 Constructing an involute (unwinding a thread)
01:25 Constructing an involute (rolling a straight line)
02:05 Radius of curvature
03:37 Nomenclature
05:08 Standard reference pitch circle
06:09 Tooth size: the module
07:17 Gear size: the standard reference pitch diameter
08:13 Circular pitch
09:06 Diametral pitch
10:15 Circular tooth thickness & tooth space width
10:55 Tip circle diameter & tooth root diameter
11:31 Standard center distance
12:32 Operating & reference pitch circle (difference)
14:02 Tooth shape: the pressure angle
15:23 Geometric similarity of involutes
17:22 Tooth shape: standard pressure angle
19:12 Gear cutting by hobbing
20:42 Base pitch (meshing pitch)