Two row radial needle roller bearing and pinion shaft for a planetary gear

摘要

A row radial needle roller bearing (50) is arranged between a pinion shaft (C) and a pinion gear (P1) of a planetary gear mechanism. There is adopted a constitution of arranging a spacer (53) at a pinion shaft center portion and arranging a retainer (52) and a roller (51) (cage & roller) at two sides thereof in order to prevent the roller (roller) from being rolled at the center portion in an axial direction of the shaft maximizing an amount of bending the shaft. At the double side rows, the bending of the shaft is not as large as that of the center portion and therefore, the roller (roller) is not hampered from being rolled smoothly.