Mesh Phase Analysis of Encased Differential Gear Train for Coaxial Twin-Rotor Helicopter

Table 1

Encased differential planetary gear train parameters.

	Encased stage				Differential stage
	Gear s1	Planet a	Planet b	Gear r1	Gear s2	Planet p	Gear r2
Tooth number	57	54	18	107	38	25	88
Module (mm)	2.75	2.75	3.5	3.5	4	4	4
Pressure angle (°)	20	20	20	20	20	20	20
Modification coefficient	+0.4618	+0.45	+0.5038	+0.2935	0	0	0
Base radius (mm)	73.65	69.77	29.6	175.96	71.42	46.98	165.39
Addendum radius (mm)	82.26	78.11	36.78	184.99	80	54	172.45
Center distance (mm)