CROSS REFERENCE TO RELATED APPLICATION

The present application claims priority to Korean Patent Application No. 10-2020-0035668 filed on Mar. 24, 2020, the entire contents of which is incorporated herein for all purposes by this reference.

BACKGROUND OF THE PRESENT INVENTION

Field of the Invention

The present invention is a technology relating to a power train mounted to an electric vehicle.

Description of Related Art

An electric vehicle is a vehicle which provides a driving force of a vehicle with power of an electric motor, and may contribute greatly to improving environmental pollution in a large city in that there is no exhaust gas.

To popularize the electric vehicle as described above, various technologies need to be improved, but there is a demand for a technology capable of dramatically improving a distance to empty after charging once.

To increase the aforementioned distance to empty, the maximum uphill performance and the highest speed performance required by the vehicle may be required to be satisfied even while improving fuel efficiency (traveling distance per unit power, km/kWh) by reducing the size and capacity of the motor which is mounted to the electric vehicle, and thus to this end, a transmission is mounted thereon.

For the aforementioned reason, the transmission mounted to the electric vehicle does not generate torque interruption, in which the torque transferred to driving wheels is disconnected upon the shift, or shift shock, even while having higher power transfer efficiency with a simple configuration as much as possible.

The information included in this Background of the present invention section is only for enhancement of understanding of the general background of the present invention and may not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

BRIEF SUMMARY

Various aspects of the present invention are directed to providing a power train for an electric vehicle, which may satisfy the maximum uphill performance and the highest vehicle speed performance required by a vehicle even while reducing the capacity of a motor by providing a large number of gear ratios, implement high power transfer efficiency with a relatively simple configuration and a small weight, improving fuel efficiency of the vehicle, and prevent torque interruption and shift shock.

A power train for an electric vehicle according to various exemplary embodiments of the present invention for achieving the object is configured to include: a planetary gear set which has a first rotation element of three rotation elements connected to a first shaft, a second rotation element thereof connected to a second shaft, and a third rotation element thereof connected to a third shaft; a first motor which is mounted to supply power to the first shaft continuously; and a second motor which is mounted to supply power to the second shaft continuously, in which the third shaft is selectively connectable to a transmission housing, and any two shafts of the first shaft, the second shaft, and the third shaft are configured to constrain rotations thereof to each other.

The first motor may have a rotation shaft mounted in parallel to the first shaft, and the second motor may have a rotation shaft mounted concentrically with the first shaft.

A first gear may be provided on the rotation shaft of the second motor, a second gear may be provided on the second shaft, and a third gear externally meshed and engaged with the first gear and a fourth gear externally meshed and engaged with the second gear may be concentrically connected to each other.

A fifth gear may be provided on the rotation shaft of the first motor, a sixth gear may be provided on the first shaft, and a seventh gear externally meshed and engaged with the fifth gear and an eighth gear externally meshed and engaged with the sixth gear may be concentrically connected to each other.

The sixth gear may be mounted to a portion where the first shaft extends through the second motor from the planetary gear set.

The first motor may have the rotation shaft directly connected to the first shaft.

The first motor may be positioned at an opposite side of the second motor with respect to the planetary gear set interposed therebetween.

The power train for the electric vehicle may be configured to include a first shifting device which is configured to fix the third rotation element of the planetary gear set to the transmission housing or to connect the third rotation element of the planetary gear set to the second shaft by linear displacement along the axial direction of the first shaft.

Furthermore, a power train for an electric vehicle according to various exemplary embodiments of the present invention for achieving the object is configured to include: a planetary gear set which has a first rotation element fixedly connected to a first shaft, a second rotation element fixedly connected to a second shaft, and a third rotation element fixedly connected to a third shaft; a first motor which is mounted to supply power to the first shaft continuously; and a second motor which is mounted to selectively supply power to the second shaft at different gear ratios, in which the third shaft may be selectively connectable to a transmission housing, and any two shafts of the first shaft, the second shaft, and the third shaft are configured to constrain rotations thereof to each other.

The power train for the electric vehicle may be configured to include a first shifting device which is configured to fix the third rotation element of the planetary gear set to the transmission housing or to connect the third rotation element of the planetary gear set to the second shaft by linear displacement along the axial direction of the first shaft.

The first motor may have a rotation shaft directly connected to the first shaft, and the second motor may have a rotation shaft mounted in parallel to the second shaft.

A first gear may be provided on the rotation shaft of the second motor, a second gear and a ninth gear may be provided on the second shaft, a fourth gear externally meshed and engaged with the second gear and a tenth gear externally meshed and engaged with the ninth gear may be rotatably mounted, respectively, to a rotation shaft of a third gear externally meshed and engaged with the first gear, and a second shifting device may be provided between the fourth gear and the tenth gear.

The second shifting device may be configured to include a hub which is fixedly mounted to the rotation shaft of the third gear and a sleeve slidably mounted on the hub.

The second motor may be mounted concentrically on the second shaft, and the first motor may be directly connected to a portion where the first shaft extends through the second motor from the planetary gear set.

The first motor may be positioned at an opposite side of the second motor with respect to the planetary gear set interposed therebetween.

The present invention may satisfy the maximum uphill performance and the highest vehicle speed performance required by a vehicle even while reducing the capacity of a motor by providing a large number of gear ratios to the electric vehicle, implement high power transfer efficiency with a relatively simple configuration and a small weight, improving fuel efficiency of the vehicle, and prevent torque interruption and shift shock.

