Abstract: A transmission system of a hybrid electric vehicle may include first and second motor/generators, a planetary gear set, first and second output gears, and first and second clutches on an axis of an input shaft receiving torque of an engine in a transmission housing, a hollow shaft disposed at a radial exterior of the input shaft and adapted to transmit the torque of the engine or torque of the first motor/generator to the second output gear, an outer shaft disposed at a radial exterior of the hollow shaft and adapted to transmit torque of the second motor/generator to the first output gear, and a rear cover coupled to a rear end portion of the transmission housing, in which the planetary gear set includes a sun gear, a planet carrier and a ring gear as rotation elements thereof.

Abstract: A transmission system of a hybrid electric vehicle may include an input shaft connected to an engine, a planetary gear set including a first rotation element operated as an output element, a second rotation element connected to the input shaft and operated as an input element, and a third rotation element operated as another output element, a first motor operably connected to the first rotation element, and selectively connected to a transmission housing, a first motor/generator configured to generate electric energy by receiving torque through the first motor shaft, a second motor shaft being a hollow shaft, disposed at a radial exterior of the first motor shaft without rotational interference with the first motor shaft, and operably connected to the third rotation element so as to receive torque of the engine, and a second motor/generator disposed on the second motor shaft and outputting torque through the second motor shaft.

Abstract: A transmission system of a hybrid electric vehicle may include an input shaft connected to an engine, a planetary gear set including a first rotation element operated as an output element, a second rotation element connected to the input shaft and operated as an input element, and a third rotation element operated as another output element, a first motor shaft disposed in parallel to and apart from the input shaft, operably connected to the first rotation element, and selectively connected to a transmission housing, a first motor/generator disposed on the first motor shaft and configured to generate electric energy by receiving torque through the first motor shaft, a second motor shaft disposed without rotational interference with the first motor shaft and operably connected to the third rotation element to receive torque of the engine, and a second motor/generator disposed on the second motor shaft and outputting torque through the second motor shaft.

Abstract: A power transmission system of a hybrid electric vehicle may include an input device including a first input shaft receiving torque of the engine and a second input shaft disposed without rotational interference with the first input shaft, a planetary gear set including a first rotation element directly connected to the second input shaft, a second rotation element directly connected to the first input shaft, and a third rotation element, a supplemental input device including a first intermediate shaft and a second intermediate shaft, a friction member selectively connecting the first intermediate shaft to a transmission housing, an output device operably connected to the input device and the supplemental input device and outputting torque transmitted from the input device or the supplemental input device, and a final reduction device decelerating torque transmitted from the output device and outputting the decelerated torque.

Abstract: A transmission system of a hybrid electric vehicle may include a first shaft connected to an engine, a first hollow shaft disposed without rotational interference with the first shaft, selectively connected to the first shaft, and provided with a first output gear, a second hollow shaft disposed without rotational interference with the first hollow shaft and provided with a second output gear, a second shaft disposed in parallel with the first shaft and connected to the first shaft through a gear unit, a clutch selectively connecting the first shaft to the first hollow shaft, a first motor/generator operably connected to the second hollow shaft, and a second motor/generator operably connected to the second shaft.

Abstract: A power transmission system of a hybrid electric vehicle may include an engine being a power source, a torque transmission device including four rotation shafts and a compound planetary gear set, the torque transmission device converting torque input from the engine, and outputting a converted torque, two supplemental power sources respectively connected to two rotation shafts among the four rotation shafts of the torque transmission device and supplying generated torque to the torque transmission device, two friction members selectively connecting two rotation shafts among the four rotation shafts of the torque transmission device to a transmission housing, an output device outputting torque transmitted from the torque transmission device, and a final reducing device decelerating torque transmitted from the output device and outputting the decelerated torque through a differential apparatus.

Abstract: A transmission system of a hybrid electric vehicle may include a first shaft connected to an engine, a first hollow shaft disposed without rotational interference with the first shaft and provided with a first output gear, a second hollow shaft disposed without rotational interference with the first hollow shaft and provided with a second output gear, a second shaft disposed in parallel with the first shaft and operably connected to the first shaft and the first hollow shaft through a gear unit so as to selectively transmit torque of the first shaft to the first hollow shaft, a clutch selectively connecting the second shaft to the first hollow shaft, a first motor/generator operably connected to the second hollow shaft, and a second motor/generator operably connected to the second shaft.

Abstract: A power transmission system of a hybrid electric vehicle may include an input shaft receiving torque of an engine, a first planetary gear set having at least three rotation elements, a second planetary gear set having at least three rotation elements, a clutch selectively connecting two rotation elements among the at least three rotation elements of the second planetary gear set, a brake selectively connecting a rotation element of the second planetary gear set to the transmission housing, and an output gear connected to a second motor/generator and the a rotation element of the second planetary gear set.

Abstract: A transmission system of a hybrid electric vehicle may include two shafts, two hollow shafts and two motor/generators. A first shaft connected to an engine. A first hollow shaft disposed without rotational interference with the first shaft, selectively connected to the first shaft, and provided with a first output gear. A second hollow shaft disposed without rotational interference with the first hollow shaft and provided with a second output gear. A second shaft disposed in parallel with the first shaft and operably connected to the first shaft and the first hollow shaft through a gear unit to selectively transmit torque of the first shaft to the first hollow shaft. Clutches may connect the first shaft and the second shaft selectively to the first hollow shaft. A first motor/generator operably connected to the second hollow shaft and a second motor/generator operably connected to the second shaft.

Abstract: A 2-speed transmission clutch learning method for a hybrid electric vehicle may include detecting whether the 2-speed transmission clutch may be operated through an actuator by driving a motor, learning an open position, a slip position, and a lock-up position of the 2-speed transmission clutch by detecting the amount of driving current and the rotation speed of the motor for the operation of the 2-speed transmission clutch, and storing learning values of the open position, the slip position, and the lock-up position of the 2-speed transmission clutch into a memory area, and controlling the operation of the 2-speed transmission clutch by applying the learning values.

Abstract: A transmission system of a hybrid electric vehicle may include an input shaft connected to an engine, first and second motors/generators disposed on a transmission housing, a planetary gear set disposed on the input shaft and having three rotation elements, of which one rotation element is connected to the transmission housing, another rotation element is connected to the input shaft, and the other rotation element is connected to the first motor/generator and operated as an output element, a first output gear disposed on the input shaft without rotational interference therebetween and connected to the second motor/generator, a second output gear disposed on the input shaft without rotational interference therebetween, and a first clutch selectively connecting the second output gear to the input shaft.

Abstract: A transmission system of a hybrid electric vehicle may include: an input shaft connected to an engine; first and second motor/generators disposed on a transmission housing; a first planetary gear set disposed on the input shaft and having three rotation elements, wherein one rotation element is connected to the transmission housing, another rotation element is connected to the first motor/generator, and the other rotation element is connected to the input shaft; a second planetary gear set disposed on the input shaft and having three rotation elements, wherein one rotation element is connected to the transmission housing, another rotation element is connected to the second motor/generator, and the other rotation element is operated as an output element; an output gear connected to the other rotation element of the second planetary gear set; and a first clutch selectively connecting the input shaft to the output gear.