Abstract: A transmission for a vehicle includes: a first planetary gear set, a second planetary gear set, a third planetary gear set, and a fourth planetary gear set each including three rotary elements; and a plurality of friction members for controlling rotation of the rotary elements. The transmission improves fuel efficiency by implementing multiple steps of shifting and improves vehicle driving comfort by using operating points in a low RPM range of an engine.

Abstract: A transmission for a vehicle may include a first planetary gear set, a second planetary gear set, a third, planetary gear set, and a fourth planetary gear set each including three rotary elements, and a plurality of friction members, in which the friction members are connected to at least one of the rotary elements of the planetary gear sets and control rotation of the rotary elements.

Abstract: A transmission for a vehicle may include a first planetary gear set, a second planetary gear set, a third, planetary gear set, and a fourth planetary gear set each including three rotary elements, and a plurality of friction members, in which the friction members are connected to at least one or more of the rotary elements of the planetary gear sets and control rotation of the rotary elements.

Abstract: A multi-stage transmission for vehicle includes an input shaft, an output shafts, first to fourth planetary gear devices each having three rotary elements and transmitting rotary forces between the input and output shafts, and at least six shifting elements connected to the rotary elements of the planetary gear devices. Of the first planetary gear device, the first rotary element is permanently connected to the input shaft and the second rotary element of the third planetary gear device, the second rotary element is installed to be fixable by any one of the shifting elements and variably connected to the first rotary element and third rotary element of the second planetary gear device, and the third rotary element is permanently connected to the second rotary element of the second planetary gear device.

Abstract: A multi-stage transmission for a vehicle includes an input shaft, an output shaft, first to fourth planetary gear devices disposed between the input shaft and the output shaft to transmit rotary forces and each of them having three rotary elements, and at least six shifting elements connected to the rotary elements of the planetary gear devices. Of the first planetary gear device, the first rotary element is permanently connected to the input shaft and a second rotary element of the third planetary gear device, a second rotary element is installed to be fixable by any one of the shifting elements and variably connected to a first rotary element of the second planetary gear device, and a third rotary element of the first planetary gear device is permanently connected to a second rotary element and variably connected to a first rotary element of the fourth planetary gear device.

Abstract: A planetary gear train of an automatic transmission for vehicles may include an input shaft receiving torque of an engine, an output shaft outputting changed torque, a first planetary gear set, a second planetary gear set, a third planetary gear set, a fourth planetary gear set, a first rotational shaft selectively connected to a transmission housing, a second rotational shaft directly connected to the input shaft, a third rotational shaft, a fourth rotational shaft, a fifth rotational shaft selectively connected to the first rotational shaft and the second rotational shaft, a sixth rotational shaft directly connected to the output shaft, a seventh rotational shaft selectively connected to the fourth rotational shaft or selectively connected to the transmission housing, an eighth rotational shaft selectively connected to the fifth rotational shaft, six friction elements disposed to selectively connect the rotational shafts or selectively connect the rotational shafts with the transmission housing.

Abstract: A multi-stage transmission for a vehicle may include an input shaft; an output shaft; first to fourth planetary gear devices transmitting rotary force between the input and output shafts, each of them having three rotary elements, and at least six shifting elements connected to the rotary elements of the planetary gear devices; wherein a first rotary element of the first planetary gear device is variably connected to a first rotary element and a third rotary element of the second planetary gear device, a second rotary element is continuously connected to the input shaft and variably connected to the first rotary element of the second planetary gear device, and a third rotary element is installed to be fixable by any one of the shifting elements and continuously connected to a third rotary element of the third planetary gear device.

Abstract: A planetary gear train of an automatic transmission for vehicles may include an input shaft receiving torque of an engine, an output shaft outputting changed torque of the engine, a first planetary gear set, a second planetary gear set, a third planetary gear set, a fourth planetary gear set, a first rotation shaft, a second rotation shaft, a third rotation shaft, a fourth rotation shaft selectively connected to the input shaft, a fifth rotation shaft selectively connected to the input shaft or selectively connected to the transmission housing, a sixth rotation shaft directly connected to the output shaft to be continuously operated as an output element, a seventh rotation shaft selectively connected to the transmission housing, an eighth rotation shaft selectively connected to the third rotation shaft, a ninth rotation shaft directly connected to the input shaft to be continuously operated as an input element, and six friction elements.

Abstract: A transmission for a vehicle may include a first planetary gear set, a second planetary gear set, a third, planetary gear set, and a fourth planetary gear set each including three rotary elements, and a plurality of friction members, wherein the friction members are connected to at least one of the rotary elements of the planetary gear sets and control rotation of the rotary elements.

Abstract: A multi-stage transmission for a vehicle includes an input shaft, an output shaft, first to fourth planetary gear devices each having three rotary elements and transmitting rotary forces between the input and output shafts, and at least six shifting elements connected to the rotary elements of the planetary gear devices. Of the first planetary gear device, the first rotary element is installed to be fixable by any one of the shifting elements and permanently connected to the second rotary element of the third planetary gear device and the third rotary element of the fourth planetary gear device, the second rotary element is variably connected to the third rotary element of the second planetary gear device and the third rotary element of the third planetary gear device, and the third rotary element is variably connected to the first and second rotary elements of the second planetary gear device.

Abstract: A planetary gear train of an automatic transmission may include: an input shaft; an output gear; a first planetary gear set including first sun gear, first planet carrier, and first ring gear; a second planetary gear set including second sun gear, second planet carrier, and second ring gear; a third planetary gear set including third sun gear, third planet carrier, and third ring gear; a fourth planetary gear set including fourth sun gear, fourth planet carrier, and fourth ring gear; a first rotation shaft including the first sun gear; a second rotation shaft including the first planet carrier, the second ring gear, the third planet carrier, and the fourth ring gear; a third rotation shaft including the first and third ring gears; a fourth rotation shaft including the second sun gear and selectively connected to a transmission housing; a fifth rotation shaft including the second planet carrier, selectively connected to the first rotation shaft and to the third rotation shaft, and directly connected to the inp

Abstract: A planetary gear train of an automatic transmission for a vehicle may include: an input shaft receiving torque of an engine; an output shaft outputting changed torque; a first planetary gear set including a first rotation element, a second rotation element, and a third rotation element; a second planetary gear set including a fourth rotation element, a fifth rotation element, and a sixth rotation element; a third planetary gear set including a seventh rotation element, an eighth rotation element, and a ninth rotation element; and a fourth planetary gear set including a tenth rotation element, an eleventh rotation element, and a twelfth rotation element.

Abstract: A multi-stage transmission for a vehicle may include an input shaft, an output shaft, a first to fourth planetary gear devices disposed between the input shaft and the output shaft to transmit rotary force, each of the first to fourth planetary gear devices having three rotary elements, and at least six shifting elements connected to the rotary elements of the planetary gear devices, wherein a first rotary element of the first planetary gear device is continuously connected to the input shaft, a second rotary element of the first planetary gear device is installed to be fixable by one shifting element of the at least six shifting elements, and a third rotary element of the first planetary gear device is continuously connected to a second rotary element of the second planetary gear device.

Abstract: A multi-stage transmission for vehicle may an input shaft, an output shafts, first to fourth planetary gear devices transmitting rotary force between the input and output shafts, each of them having three rotary elements, and at least six shifting elements connected to the rotary elements of the planetary gear devices, wherein first rotary element of the first planetary gear device is permanently connected to the input shaft, second rotary element is installed to be fixable by any one of the shifting elements, and third rotary element is permanently connected to second rotary element of the second planetary gear device.

Abstract: A multi-stage transmission for vehicle may include an input shaft; and an output shafts; first to fourth planetary gear devices transmitting rotary force between the input and output shafts, each of them having three rotary elements; and at least six shifting elements connected to the rotary elements of the planetary gear devices; wherein first rotary element of the first planetary gear device is permanently connected to the input shaft and second rotary element of the third planetary gear device, second rotary element is installed to be fixable by any one of the shifting elements and variably connected to first rotary element of the third planetary gear device and first rotary element of the fourth planetary gear device, and third rotary element is variably connected to first rotary element of the second planetary gear device and permanently connected to second rotary element of the second planetary gear device.

Abstract: A planetary gear train of an automatic transmission for a vehicle may include an input shaft receiving rotary power of an engine, an output gear outputting the rotary power with rotary speed changed, a first planetary gear set, a second planetary gear set, a third planetary gear set, a fourth planetary gear set, a first rotating shaft, a second rotating shaft, a third rotating shaft, a fourth rotating shaft selectively connected with the third rotating shaft and a transmission housing simultaneously, a fifth rotating shaft selectively connected with the first rotating shaft and the input shaft simultaneously, a sixth rotating shaft, a seventh rotating shaft selectively connected with the sixth rotating shaft and the transmission housing simultaneously, an eighth rotating shaft selectively connected with the sixth rotating shaft and the output gear simultaneously, and six friction elements.

Abstract: A transmission for a vehicle may include a first planetary gear set, a second planetary gear set, a third, planetary gear set, and a fourth planetary gear set each including three rotary elements, and a plurality of friction members, in which the friction members are connected to at least one or more of the rotary elements of the planetary gear sets and control rotation of the rotary elements.

Abstract: A multi-stage transmission for a vehicle may include an input shaft; an output shaft; first to fourth planetary gear devices transmitting rotary force between the input and output shafts, each of them having three rotary elements; and at least six shifting elements connected to the rotary elements of the planetary gear devices; wherein first rotary element of the first planetary gear device is installed to be fixable by any one of the shifting elements and variably connected to second rotary element of the second planetary gear device, second rotary element is continuously connected to the input shaft and variably connected to third rotary element of the second planetary gear device, and third rotary element is variably connected to the second rotary element of the second planetary gear device and continuously connected to first rotary element of the third planetary gear device.

Abstract: A transmission for a vehicle may include a first planetary gear set, a second planetary gear set, a third, planetary gear set, and a fourth planetary gear set each including three rotary elements, and a plurality of friction members, in which the friction members are connected to at least one or more of the rotary elements of the planetary gear sets and control rotation of the rotary elements.

Abstract: A multi-stage transmission for a vehicle may include an input shaft, an output shaft, first to fourth planetary gear devices disposed between the input shaft and the output shaft to transmit rotary force, each of them having three rotary elements, and at least six shifting elements connected to the rotary elements of the planetary gear devices, wherein a first rotary element of the first planetary gear device is continuously connected to the input shaft and variably connected to a second rotary element of the first planetary gear device, the second rotary element is installed to be fixable by one shifting element of the at least six shifting elements, and a third rotary element of the first planetary gear device is continuously connected to a second rotary element of the second planetary gear device and variably connected to a third rotary element of the third planetary gear device.