| 摘要 |
In a main transmission gearbox for a helicopter having two engines, a lifting rotor and an anti-torque rotor, each of the two engines drives a main kinematic chain comprising from upstream down, an input shaft, a twistable shaft, a gear train forming a first reduction stage having a first bevel pinion meshing with a second bevel pinion which drives in rotation a vertical shaft bearing having a third pinion in mesh with a gearwheel which is common to the two main chains and forms with the third pinions a second reduction stage. The torque received at the gearwheel is transmitted to the driving shaft of the main rotor by way of a supplementary reduction stage of epicyclic type. A third chain comprising two input pinions each of which is mounted upon one of the input shafts and an intermediate pinion which drives the driving shaft of the anti-torque rotor, ensures the distribution of power over the two main chains in the event of breakdown of one engine. |
