Power transmission device

A power transmission device comprising left and right clutches (29, 30) including:

• left and right output shafts (23, 24) supported on a housing (11, 12, 13), the left and right output shafts (23, 24) being coaxial and rotatable relative to each other;
• an input shaft (20) disposed on an outer periphery of one of the left and right output shafts (23, 24) in such a way as to be rotatable relative thereto;
• a clutch outer (42) coupled to the input shaft (20);
• left and right clutch inners (50, 61) coupled to the left and right output shafts (23, 24), respectively;
• a plurality of left frictional engagement members (54) disposed between the clutch outer (42) and the left clutch inner (50);
• a plurality of right frictional engagement members (62) disposed between the clutch outer (42) and the right clutch inner (61);
• a left clutch piston (55) configured to press the left frictional engagement members (54) toward the right frictional engagement members (62);
• and
• a right clutch piston (63) configured to press the right frictional engagement members (62) toward the left frictional engagement members (54),
• characterized in that
• the clutch outer (42) includes
• a boss portion (42a) positioned in an axial direction between the left and right clutch inners (50, 61) through a thrust bearing (41, 53),
• left and right disk portions (42b, 42d) branching in two ways from the boss portion (42a) so as to support pressures of the left and right clutch pistons (55, 63) transmitted through the left and right frictional engagement members (54, 62), respectively, and
• left and right drum portions (42c, 42e) extending in the axial direction from the left and right disk portions (42b, 42d) so as to guide outer peripheral portions of the left and right frictional engagement members (54, 62), respectively, and
• a gap (α) is formed between the left and right disk portions (42b, 42d).