Abstract: A forward/reverse switching mechanism is provided with a planetary gear set, a reverse brake and a forward clutch. The planetary gear set includes a sun gear which serves as an input part, a carrier which serves as an output part, and a ring gear. The reverse brake is adapted to fix the ring gear. The forward clutch is adapted to connect the ring gear and the sun gear to each other. The ring gear, a drive plate provided on a ring gear side of the reverse brake and a driven plate provided on a ring gear side of the forward clutch are spline-fitted to a clutch drum.

Abstract: Disclosed is a support structure for a ring gear, which includes: a clutch drum coupled by spline fitting with the ring gear; and first and second snap rings mounted to a circumferential wall of the clutch drum and supporting the ring gear. The first snap ring is positioned so as not to overlap with the ring gear in a radial direction. The second snap ring is positioned so as to overlap with the ring gear in the radial direction. A length of the first snap ring in the radial direction is longer than a length of the second snap ring in the radial direction.

Abstract: Disclosed is a support structure for a ring gear (32), which includes: a clutch drum (6) coupled by spline fitting with the ring gear (32); and first and second snap rings (38, 39) mounted to a circumferential wall (62) of the clutch drum (6) and supporting the ring gear (32). The first snap ring (38) is positioned so as not to overlap with the ring gear (32) in a radial direction. The second snap ring (39) is positioned so as to overlap with the ring gear (32) in the radial direction. A length (a1) of the first snap ring (38) in the radial direction is longer than a length (a2) of the second snap ring (39) in the radial direction.

Abstract: Disclosed is a forward/reverse switching mechanism (2) with a planetary gear set (3), a reverse brake (5) and a forward clutch (4). The planetary gear set (3) includes a sun gear (31) which serves as an input part, a carrier (34) which serves as an output part, and a ring gear (32). The reverse brake (5) is adapted to fix the ring gear (32). The forward clutch (4) is adapted to connect the ring gear (32) and the sun gear (31) to each other. The ring gear (32), a drive plate (52) provided on a ring gear (32) side of the reverse brake (5) and a driven plate (41) provided on a ring gear (32) side of the forward clutch (4) are spline-fitted to a clutch drum (6).