Power train device for electric vehicle
A power train device for an electric vehicle includes a first planetary gear set including a first sun gear, a first ring gear, a first planet gear, and a first carrier, a second planetary gear set including a second sun gear, a second ring gear, a second planet gear, and a second carrier, a third planetary gear set including a third ring gear, a third planet gear, and a third carrier, and a sleeve having an inner-diameter portion on which a first engagement part is provided, the first engagement part being configured to engage, at ordinary times, with a third engagement part provided on the first ring gear.
1 . A power train device for an electric vehicle, the power train device comprising:
a first planetary gear set comprising a first sun gear coupled to an input shaft connected to a drive motor, a first ring gear surrounding the first sun gear, a first planet gear configured to engage with the first sun gear and the first ring gear between the first sun gear and the first ring gear, and a first carrier configured to support the first planet gear so that the first planet gear is rotatable; and
a sleeve having an inner-diameter portion having a first engagement part thereon, the first engagement part being configured to:
engage with a third engagement part disposed on an outer-diameter portion of the first ring gear;
move along an axial direction of the input shaft while engaging with the third engagement part toward a casing to implement a first shift operation for a first speed range; and
move along the axial direction of the input shaft while engaging with the third engagement part toward the first carrier to implement a second shift operation for a second speed range,
wherein a second engagement part is disposed on one surface of the sleeve, a fourth engagement part is disposed in the casing, a fifth engagement part is disposed on one surface of the first carrier, and a sixth engagement part is disposed on another surface of the sleeve facing the fifth engagement part,
wherein the second engagement part and the fourth engagement part have first radial dog- type teeth facing one another, and the fifth engagement part and the sixth engagement part have second radial dog-type teeth facing one another.
2 . The power train device of claim 1 , wherein during the first shift operation, the sleeve is configured to move in a first shift direction, such that the second engagement part engages with the fourth engagement part in the casing while the first engagement part engages with the third engagement part.
3 . The power train device of claim 2 , wherein during the second shift operation, the sleeve is configured to move in a second shift direction, such that the second engagement part disengages from the fourth engagement part and the sixth engagement part engages with the fifth engagement part while the first engagement part engages with the third engagement part.
4 . The power train device of claim 2 ,
wherein the first engagement part and the third engagement part have spline teeth of internal gears.