The gear transmission system of flying vehicle studied in this paper is composed of one-stage planetary gear train and two-stage bevel gear transmission. The planetary gear train is composed of sun gear s, three idler gears I, three planetary gears P and ring gear R, hereinafter referred to as DSI planetary gear train; The bevel gear system consists of two-stage spiral bevel gears. As shown in the figure.
During the flight of the flying vehicle, the power flow direction of the bevel gear transmission system is from the engine to the sun gear s, shunted to the idler gear I, then transmitted to the planetary gear P, and transmitted to the bevel gear B1, bevel gear B2 and bevel gear B3 through the output of ring gear R. finally, it is connected to the outside through bevel gear B4 to control the rotation of the propeller. The parameters of the bevel gear transmission system are: number of teeth ZS = 50, Zi = 19, ZP = 20, Zr = 101, zb1 = 17, ZB2 = 43, zb3 = 17, zb4 = 53; Modulus Ms = Mi = MP = Mr = 2 25 mm ， mB1=mB2=2. 5 mm，mB3=mB4=3 mm； Spiral angle of spiral bevel gear is 35 °; The tooth width of each gear in DSI planetary gear train is 15 mm, the tooth width of bevel gear B1 and bevel gear B2 is 25 mm, and the tooth width of bevel gear B3 and bevel gear B4 is 35 mm; The pressure angle of each gear is 20 °, and the gear material is 9310 steel.