Effects of Non-torque Loads and Carrier Pinhole Position Errors on Planet Load Sharing of Wind Turbine Gearbox

Abstract

The effects of carrier pinhole position errors and non-torque loads on the load sharing of planet gears in a conventional-type three-point suspension wind turbine gearbox were investigated. A 1/4 scale-down model of a 2-MW class wind turbine gearbox was used, and a parametric study was conducted using a three-dimensional analysis model capable of performing system-level analysis. Axial force, radial force, and bending moment were used as non-torque loads, and the mesh load factor was used as an index representing the load sharing characteristics of the planet gears. The results of the analysis showed that the radial force and the moment were major non-torque load elements that affect the load sharing of the planet gears. The magnitudes, positions, and phases of pinhole position errors also made a significant impact on the load sharing characteristics of the planet gears. When non-torque loads and pinhole position errors acted together, the influence of pinhole position errors was greater than that of the non-torque loads. Their combination effect will be different according to the characteristics of drive train system. Therefore, the analysis that reflects actual specifications and operating conditions of all the drive train system components is necessary to derive the planet load sharing characteristics accurately.

Analytical study of floating effects on load sharing characteristics of planetary gearbox for off-road vehicle

“…As previous studies reported, the power transmitted to each planet gear appeared as a periodic function depending on the carrier rotation angle whether only non-torque load or both non-torque load and carrier pinhole position error were considered. 6,17 Furthermore, because the actual carrier pinhole position error of the PGS was 50 mm presented by the manufacturer, an error of + 100 mm was applied to pinhole 1 to assume the worst load-sharing condition. without any floating member.…”

“…In practice, however, it is well-known that uneven load sharing occurs owing to non-torque loads and various manufacturing and assembly errors. [1][2][3][4][5][6][7] Because uneven load sharing, due to manufacturing and assembly errors, reduces the life of planet gears, many studies have attempted to solve this problem. Kahraman 4 developed a mathematical model of a PGS to analyze the dynamic load-sharing characteristics.…”

“…Many studies have investigated the effects of non-torque loads on the load-sharing characteristics of a PGS. 6,11,[14][15][16][17] These works have used analytical and experimental methods to investigate the load-sharing characteristics of a PGS when both torque and nontorque loads are applied to a gearbox for wind turbines. However, little work has been conducted about the load-sharing characteristics of a reduction gearbox for off-road vehicles such as forklifts and farm tractors, because they are generally engine-driven and weight reduction of the gearbox is not important.…”

“…In practice, however, it is well-known that uneven load sharing occurs owing to non-torque loads and various manufacturing and assembly errors. 1–7…”

“…With the carrier pinhole position errors, a non-torque load is recently considered as one of the main causes for the uneven load sharing. 6,12,13 The non-torque load is defined as a load component with five degrees of freedom due to the self-weight or irregular workload, but not torque, of the mechanical system. Many studies have investigated the effects of non-torque loads on the load-sharing characteristics of a PGS.…”