Automatic transmission for vehicles

An automatic transmission comprising:

• an input first rotating member;
• an output second rotating member provided to be coaxial with the first rotating member;
• a third rotating member provided to be coaxial with the first rotating member;
• and
• rotation transmitting means provided on the third rotating member to transmit rotation of the first rotating member to the second rotating member so that the second rotating member is rotated at a number of revolution and a reduction ratio shown by following equations respectively in a direction of rotation of the first rotating member:
• N2=N3+(N1−N3)/R0
• R=N1·R0/((R0−1)·N3+N1)
• where N1 is a number of revolution of the first rotating member, N2 is a number of revolution of the second rotating member, N3 is a number of revolution of the third rotating member, R is a reduction ratio of the automatic transmission, and R0 is a reduction ratio of the automatic transmission in a stopped state of the third rotating member and larger than 1, wherein the third rotating member is bidirectionally rotatable in a free state;
• and the second rotating member is automatically adjusted to a number of revolution at which an equilibrium is maintained between torque developed by the second rotating member and a load applied to the second rotating member when the third rotating member is in rotation at a number of revolution ranging between zero at which the third rotating member is stationary and a number of revolution at which the third rotating member is in rotation together with the first rotating member in one and the same direction.