The present invention discloses a power transmission apparatus. The power transmission apparatus includes: an input shaft including a male screw portion formed thereon; a pair of input gears formed on the input shaft to be freely rotatable with the male screw portion being interposed therebetween; an output gear formed to be rotatable in a state of being linked with the pair of input gears; and a power interrupting unit screw-coupled to the male screw portion of the input shaft, and configured to rectilinearly reciprocate along the input shaft by a rotation of the input shaft to be selectively engaged with any one of the pair of input gears so as to transmit a power.

An input synthesis apparatus according to the present invention includes: a first input unit which provides first rotational force; a second input unit which provides second rotational force equal to or different from the first rotational force; a gear unit which is engaged with the first input unit and the second input unit and synthesizes the first rotational force and the second rotational force; and an output unit which outputs resultant force of the first rotational force and the second rotational force, in which the gear unit sums up speeds or torque of the first rotational force and the second rotational force based on whether a rotation direction of the first input unit and a rotation direction of the second input unit are identical to each other.

The invention is directed to a freewheel mechanism comprising: a) an input shaft, which rotates at an input speed; b) an output shaft, which rotates at an output speed; c) a first differential-gear or planetary-gear system, which is arranged between the two shafts and comprises at least one toothed orbital or planetary gear, which is rotatably mounted in a first orbital-gear or planetary-gear carrier and meshes with two internal toothed rings on two further rotary connections of the first differential-gear or planetary-gear system, the speeds thereof determining the speed of the first orbital-gear or planetary-gear carrier in the first differential-gear or planetary-gear system; d) a second differential-gear or planetary-gear system, which comprises at least one toothed orbital or planetary gear, which is rotatably mounted in a second orbital-gear or planetary-gear carrier and meshes with two internal toothed rings on two further rotary connections of the second differential-gear or planetary-gear system, the speeds thereof determining the speed of the second orbital-gear or planetary-gear carrier in the second differential-gear or planetary-gear system; and e) a housing, in which both or all the differential-gear or planetary-gear systems are accommodated.

A two-stage speed-change output device includes a main axle, on which a motor assembly and first and second speed-change assemblies are mounted. The first and second speed-change assemblies are mounted inside an output shell by first and second one-way clutching elements, both operating in a forward direction. The motor assembly is operable to rotate backward to drive the first one-way clutching element to drive the output shell to rotate in the forward direction, while the second one-way clutching element idles. The motor assembly is also operable to rotate forward to drive the second one-way clutching element to drive the output shell to rotate in the forward direction, while the first one-way clutching element idles. The device realizes speed change for two stages to drive the output shell in the same direction with forward and backward rotations of the motor assembly.

Disclosed is a power transmission device including a motor including a rotary shaft, a speed reducer provided on one side of the motor, and a power transmitter, provided inside the speed reducer, that transmits rotational force generated by driving of the motor to the speed reducer. The power transmitter transmits the power such that a ratio of rotational angular velocity of the speed reducer to rotational angular velocity of the rotary shaft is changed according to rotation directions of the rotary shaft of the motor.

A vehicle transmission using a gearset. Multi-mode clutches selectively couple components of the gearset. The transmission operates in and shifts between a first forward gear and a second forward gear using a change in input rotation. An electric motor coupled to the input may be used to change the input rotation direction.

A vehicle transmission using a gearset. Multi-mode clutches selectively couple components of the gearset. The transmission operates in and shifts between a first forward gear and a second forward gear using a change in input rotation. An electric motor coupled to the input may be used to change the input rotation direction.