Research of Deformability of Satellite Unit of Planetary Transmission

Abstract

Multistream planetary gears are widely used in engineering due to good technical and economic indicators: high load capacity with small dimensions and weight, small losses of frictional power, large gear ratio in one stage. A significant disadvantage of these transmissions is the uneven distribution of the load in the gears of the wheels, which is caused by the inevitable manufacturing errors and deformations of their links. However, the compliance of the individual transmission elements (axes and bearings of the satellites, the cheeks of the carrier) facilitates the equalization of the load both over the satellites and their rows in the case of multi-row execution of the mechanism. In this connection, it is important to establish the degree of influence of the deformation of the planetary gear elements on the load distribution in gears of the wheels and on such an important technical and economic indicator as the mass ratio to the torque on the output shaft. The coefficient of uneven distribution of the load across satellites was determined from the solution of the system of equations for the compatibility of displacements, taking into account the deformation of the cheek of the carrier, the bearings and the axes of the satellites. Moreover, the axis of the satellite in the places of its interface with the cheeks of the carrier and the ring of the rolling bearing was considered as a beam on an elastic base, and the cheeks of the carrier were made with grooves to reduce their rigidity. Thus, it was found that the performance of compliant carrier cheeks allows to reduce the coefficient of unevenness of load distribution by satellites by 8% -11%, which favorably affects the bearing capacity of the drive and its weight and dimensions. With a limited radial transmission size, it is advisable to perform multi-row transmission. However, in this case, the deformation of the torsion of the sun gear leads to an uneven distribution of the load along the rows of satellites. To prevent this negative phenomenon, it is suggested to produce the carrier with different widths of bridges, the dimensions of which should be chosen so that their deformation corresponds to the deformation of the pinion torsion. Thus, the use of the proposed designs of multistream planetary gears with a rational choice of their parameters can significantly reduce the uneven load distribution in gears and improve the technical and economic performance of the drive.