Power transmission device of electric vehicle

Abstract

The present invention provides a power transmission device of an electric vehicle, comprising: a first planetary gear set composed of a first sun gear, a first ring gear, a first planetary gear and a first carrier; a second planetary gear set composed of a second sun gear, a second ring gear, a second planetary gear and a second carrier; a third planetary gear set composed of a third ring gear, a third planetary gear and a third carrier; and a sleeve having a first engagement part provided on the inner diameter portion thereof, wherein the first engagement part engages at all times with a third engagement part provided on the first ring gear.

Description

Powertrain of electric vehicles

[0001] The present invention relates to a power transmission device for an electric vehicle.

[0002] Demand for electric vehicles (fuel cell vehicles) for commercial vehicles such as trucks and buses is increasing to meet emission regulations and reduce fossil fuel use.

[0003] In electric vehicles, the power of the drive motor can be transmitted to the drive wheels through the reducer and axle.

[0004] The power electric (PE) system of a conventional electric vehicle can be divided into a central motor type that receives power from a drive motor and transmits the power to an axle through a reduction gear, and an electric axle (E-Axle) type that includes a drive motor, a reduction gear, and an axle differential.

[0005] Compared to internal combustion engine vehicles, electric vehicles require a more compact power electric (PE) system that combines a motor, inverter, and reducer due to increased installation space for battery packs.

[0006] However, due to the inherent powertrain layout characteristics of the electric axle (E-Axle), it has been difficult to meet the performance requirements of electric vehicles with a single-stage reduction gearbox. Furthermore, applying a high-performance drive motor not only requires a large amount of installation space, but also increases costs.

[0007] [Prior Art Literature]

[0008] [Patent Document]

[0009] (Patent Document 1) Republic of Korea Patent Publication No. 10-2007-0076773 (published on July 25, 2007)

[0010] In order to solve the above-mentioned problem, the present invention provides a power transmission device for an electric vehicle that can be easily mounted on a vehicle package due to a reduction structure composed of a plurality of planetary gear sets.

[0011] In order to achieve the above-mentioned object, the present invention comprises a first planetary gear set comprising a first sun gear coupled to an input shaft connected to a driving motor, a first ring gear configured to surround the first sun gear, a first planetary gear meshed with the first sun gear and the first ring gear between the first sun gear and the first ring gear, and a first carrier that rotatably supports the first planetary gear; a second planetary gear set comprising a second sun gear connected to the first carrier by power, a second ring gear configured to surround the second sun gear, a second planetary gear meshed with the second sun gear and the second ring gear between the second sun gear and the second ring gear, and a second carrier that rotatably supports the second planetary gear; A power transmission device for an electric vehicle is provided, comprising: a third planetary gear set comprising a third ring gear configured to surround the second ring gear, a third planetary gear meshed with the second ring gear and the third ring gear between the second ring gear and the third ring gear, and a third carrier that rotatably supports the third planetary gear; and a sleeve having a first engagement portion provided on an inner diameter, the first engagement portion constantly meshing with the third engagement portion provided on the first ring gear.

[0012] Additionally, the first planetary gear set, the second planetary gear set, and the third planetary gear set can be mounted inside the case.

[0013] Additionally, a second engagement portion may be provided on the outer diameter of the sleeve, and a fifth engagement portion may be provided on the outer diameter of the first carrier (first embodiment).

[0014] In addition, when shifting to the first gear, as the sleeve moves in the first gear shift direction, the first engagement portion can be engaged with the third engagement portion while the second engagement portion can be engaged with the fourth engagement portion inside the case (first embodiment).

[0015] In addition, when shifting in two gears, as the sleeve moves in the two-speed shifting direction, the first engagement portion is simultaneously engaged with the fifth engagement portion while maintaining an engagement state with the third engagement portion, and the second engagement portion can be separated from the fourth engagement portion (first embodiment).

[0016] In addition, the first engagement portion and the third and fifth engagement portions may be configured with spline teeth of an internal gear, and the second engagement portion and the fourth engagement portion may be configured with spline teeth of an internal gear (first embodiment).

[0017] In addition, a second engagement portion may be provided on one side of the sleeve, a fifth engagement portion may be provided on one side of the first carrier, and a sixth engagement portion may be provided on the other side of the sleeve opposite to the fifth engagement portion (second embodiment).

[0018] In addition, when shifting to the first gear, as the sleeve moves in the first gear shift direction, the first engagement portion can be engaged with the third engagement portion while the second engagement portion can be engaged with the fourth engagement portion inside the case (second embodiment).

[0019] In addition, when shifting in two gears, as the sleeve moves in the two-speed shift direction, the first engagement portion can maintain a state of engagement with the third engagement portion, while the second engagement portion can be separated from the fourth engagement portion and the sixth engagement portion can be engaged with the fifth engagement portion (second embodiment).

[0020] In addition, the first engagement portion and the third engagement portion may be configured with spline teeth of an internal gear, the second engagement portion and the fourth engagement portion may be configured with radial dog-type teeth facing each other, and the fifth engagement portion and the sixth engagement portion may be configured with radial dog-type teeth facing each other (second embodiment).

[0021] Additionally, a fifth engagement portion may be provided on the outer diameter of the first carrier, and a fourth engagement portion may be provided inside the case (third embodiment).

[0022] In addition, when shifting to the first gear, as the sleeve moves in the first gear shifting direction, the first engagement portion can be simultaneously engaged with the fourth engagement portion while maintaining an engaged state with the third engagement portion (third embodiment).

[0023] In addition, when shifting in two gears, as the sleeve moves in the two-speed shifting direction, the first engagement portion can be simultaneously engaged with the fifth engagement portion while maintaining an engagement state with the third engagement portion (third embodiment).

[0024] Additionally, the first engagement portion and the fourth and fifth engagement portions may be configured as spline teeth of an internal gear (third embodiment).

[0025] Additionally, the number of the second planetary gears may be configured to exceed the number of the third planetary gears.

[0026] Additionally, the second planetary gears may be arranged in six pieces along the outer diameter of the second sun gear, and the third planetary gears may be arranged in five pieces along the outer diameter of the second ring gear.

[0027] Additionally, the third carrier can be fixed to the case.

[0028] Additionally, the power transmitted to the second carrier can be transmitted to one axle shaft via the intershaft, and the power transmitted to the third ring gear can be transmitted to the other axle shaft.

[0029] Additionally, the sleeve can be moved in a one-speed or two-speed direction by the control unit.

[0030] The present invention can be easily mounted on a vehicle package due to a reduction structure composed of a plurality of planetary gear sets.

[0031] In addition, the present invention enables 1st and 2nd gear shifting, so that low-speed vehicle speed control and high-speed vehicle speed control are possible.

[0032] In addition, since the present invention is composed of a plurality of planetary gear sets, it does not take up much space when installed in a vehicle.

[0033] In addition, the present invention can control the speed change by the operation of the sleeve.

[0034] In addition, the present invention can reduce the number of parts compared to the power transmission device of an existing electric vehicle, thereby reducing cost, reducing weight, and simplifying the assembly process.

[0035] FIG. 1 is a drawing showing a single-stage operation according to a preferred embodiment of the present invention.

[0036] FIG. 2 is a drawing showing a two-stage operation according to a preferred embodiment of the present invention.

[0037] FIG. 3 is a drawing showing the operation of the 1st, Nth and 2nd stage sleeves according to the first embodiment of the present invention.

[0038] FIG. 4 is a drawing showing a first planetary gear set according to a preferred embodiment of the present invention.

[0039] FIG. 5 is a drawing showing a second and third planetary gear set according to a preferred embodiment of the present invention.

[0040] FIG. 6 is a drawing showing the operation of the 1st, Nth, and 2nd stage sleeves according to the second embodiment of the present invention.

[0041] FIG. 7 is a drawing showing the operation of the 1st, Nth, and 2nd stage sleeves according to the third embodiment of the present invention.

[0042] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. First, when assigning reference numerals to components in each drawing, it should be noted that identical components are assigned the same numerals as much as possible even if they are shown in different drawings. Furthermore, in describing the present invention, if a detailed description of a related known structure or function is judged to obscure the gist of the present invention, the detailed description thereof will be omitted. In addition, although preferred embodiments of the present invention will be described below, it should be understood that the technical idea of ​​the present invention is not limited thereto and can be modified and implemented in various ways by those skilled in the art.

[0043] FIG. 1 is a drawing showing the operation of the first stage according to a preferred embodiment of the present invention, FIG. 2 is a drawing showing the operation of the second stage according to a preferred embodiment of the present invention, FIG. 3 is a drawing showing the operation of the sleeves in the first, N and second stages according to the first embodiment of the present invention, FIG. 4 is a drawing showing the first planetary gear set according to a preferred embodiment of the present invention, and FIG. 5 is a drawing showing the second and third planetary gear sets according to a preferred embodiment of the present invention.

[0044] As illustrated in FIGS. 1 to 5, the present invention may include a first planetary gear set (PS1) that is connected to a driving motor (MG) for power, a second planetary gear set (PS2) that is connected to the first planetary gear set (PS1) for power, a third planetary gear set (PS3) that is connected to the second planetary gear set (PS2) for power, and a sleeve (SL) that moves in an axial direction to perform a one-stage shift or a two-stage shift.

[0045] The driving motor (MG) may be composed of a stator (ST) and a rotor (RT). The driving motor (MG) may be connected to an inverter (INV).

[0046] The first planetary gear set (PS1), the second planetary gear set (PS2), the third planetary gear set (PS3) and the sleeve (SL) can be mounted inside the case (CS).

[0047] The first planetary gear set (PS1) may include a first sun gear (S1), a first planetary gear (P1), a first carrier (C1), and a first ring gear (R1).

[0048] The first sun gear (S1) may be mounted on the outer diameter of the input shaft (IP) connected to the driving motor (MG). The first sun gear (S1) may be located inside the first ring gear (R1).

[0049] The first ring gear (R1) can be configured to surround the first sun gear (S1).

[0050] The first planetary gear (P1) can be simultaneously engaged with the first sun gear (S1) and the first ring gear (R1) between the first sun gear (S1) and the first ring gear (R1). The first planetary gears (P1) can be arranged in multiples along the outer diameter of the first sun gear (S1). For example, five first planetary gears (P1) can be arranged along the outer diameter of the first sun gear (S1).

[0051] The first carrier (C1) may be formed integrally with the first planetary gear (P1). The first planetary gear (P1) may rotate while being supported by the first carrier (C1).

[0052] The second planetary gear set (PS2) may include a second sun gear (S2), a second planetary gear (P2), a second carrier (C2), and a second ring gear (R2).

[0053] The second sun gear (S2) can be powered by the first carrier (C1). The second sun gear (S2) can be located inside the second ring gear (R2).

[0054] The second ring gear (R2) may be configured to surround the second sun gear (S2). The second ring gear (R2) may perform the ring gear function of the second planetary gear set (PS2) and the sun gear function of the third planetary gear set (PS3).

[0055] The second planetary gear (P2) can be simultaneously engaged with the second sun gear (S2) and the second ring gear (R2) between the second sun gear (S2) and the second ring gear (R2). The second planetary gears (P2) can be arranged in multiples along the outer diameter of the second sun gear (S2). For example, six second planetary gears (P2) can be arranged along the outer diameter of the second sun gear (S2).

[0056] The second carrier (C2) may be formed integrally with the second planetary gear (P2). The second planetary gear (P2) may rotate while supported by the second carrier (C2). One side of the second carrier (C2) may be connected to an intershaft (IS). The intershaft (IS) may be connected to an axle shaft (not shown) on one side.

[0057] The third planetary gear set (PS3) may include a third planetary gear (P3), a third carrier (C3), and a third ring gear (R3).

[0058] The third ring gear (R3) may be configured to surround the second ring gear (R2). The third planetary gear (P3) may be simultaneously engaged with the second ring gear (R2) and the third ring gear (R3) between the second ring gear (R2) and the third ring gear (R3). The third planetary gears (P3) may be arranged in multiples along the outer diameter of the second ring gear (R2). For example, five third planetary gears (P3) may be arranged along the outer diameter of the second ring gear (R2).

[0059] The third carrier (C3) may be formed integrally with the third planetary gear (P3). The third planetary gear (P3) may rotate while supported by the third carrier (C3). The third carrier (C3) may be fixed to the case (CS).

[0060] One end of the third ring gear (R3) may be connected to the other axle shaft (AS). The intershaft (IS) and the other axle shaft (AS) may be configured to be opposite each other. For example, the intershaft (IS) may be configured to penetrate the interior of the input shaft (IP).

[0061] A sleeve (SL) performing a gear change operation may include a first engagement portion (IR1) and a second engagement portion (IR2). The first engagement portion (IR1) may be provided on an inner diameter of the sleeve (SL). The second engagement portion (IR2) may be provided on an outer diameter of the sleeve (SL). The first engagement portion (IR1) and the second engagement portion (IR2) may be configured as splines. The first engagement portion (IR1) may be permanently engaged with a third engagement portion (IR3) provided on an outer diameter of the first ring gear (R1).

[0062] When the sleeve (SL) moves in the first gear shift direction, the second engagement portion (IR2) can engage with the fourth engagement portion (IR4) provided inside the case (CS). Even when the sleeve (SL) moves in the first gear shift direction, the engagement state of the first engagement portion (IR1) and the third engagement portion (IR3) can be maintained (see (a) of FIG. 3).

[0063] When shifting to the N (Natural) gear, the second engagement portion (IR2) may disengage from the third engagement portion (IR3) as the sleeve (SL) moves in the N gear shift direction. Even when the sleeve (SL) moves in the N gear shift direction, the engagement state of the first engagement portion (IR1) and the third engagement portion (IR3) may be maintained (see (b) of FIG. 3).

[0064] When the sleeve (SL) moves in the second gear shift direction, the first engagement portion (IR1) can be simultaneously engaged with the third engagement portion (IR3) and the fifth engagement portion (IR5) provided on the outer diameter of the first carrier (C1). When the sleeve (SL) moves in the second gear shift direction, the second engagement portion (IR2) and the fourth engagement portion (IR4) can be disengaged (see (c) of FIG. 3).

[0065] The first ring gear (R1) is fixed so that it cannot rotate when shifting to the first gear, and is released from the fixation when shifting to the second gear so that it can rotate as one unit with the first carrier (C1). The first carrier (C1) is powered by the second sun gear (S2), so that the first carrier (C1) and the second sun gear (S2) can always rotate as one unit.

[0066] As shown in Fig. 3, the first engagement portion (IR) and the third and fifth engagement portions (IR3, IR5) may be configured with a spline tooth shape of an internal gear. The second engagement portion (IR2) and the fourth engagement portion (IR4) may be configured with a spline tooth shape of an internal gear.

[0067] As shown in FIGS. 1 to 3, the operation of the sleeve (SL) can be controlled by a control unit (Control). The sleeve (SL) can move in a single-speed or two-speed direction by the operation of the control unit (Control). For example, the control unit (Control) may be an actuator.

[0068] FIG. 6 is a drawing showing the operation of the 1st, Nth, and 2nd stage sleeves according to the second embodiment of the present invention.

[0069] As illustrated in FIG. 6, the second embodiment of the present invention can be configured identically to the first embodiment except for the mating portion.

[0070] A second engagement portion (IR2) may be provided on one side of the sleeve (SL). A fifth engagement portion (IR5) may be provided on one side of the first carrier (C1). A sixth engagement portion (IR6) may be provided on the other side of the sleeve (SL) opposite to the fifth engagement portion.

[0071] The first meshing portion (IR) and the third meshing portion (IR3) may be configured with spline teeth of an internal gear. The teeth of the first meshing portion (IR) and the third meshing portion (IR3) may be configured in a square or trapezoidal shape while being formed at a certain interval.

[0072] The second engagement portion (IR2) and the fourth engagement portion (IR4) may be configured with radial dog-type teeth facing each other. The teeth of the second engagement portion (IR2) and the fourth engagement portion (IR4) may be configured in a square or trapezoidal shape while being formed at a certain interval.

[0073] The fifth engagement portion (IR5) and the sixth engagement portion (IR6) may be configured with radial dog-type teeth facing each other. The teeth of the fifth engagement portion (IR5) and the sixth engagement portion (IR6) may be configured in a square or trapezoidal shape while being formed at a certain interval.

[0074] FIG. 7 is a drawing showing the operation of the 1st, Nth, and 2nd stage sleeves according to the third embodiment of the present invention.

[0075] As illustrated in FIG. 7, the third embodiment of the present invention can be configured identically to the first embodiment except for the mating portion.

[0076] A fifth engagement portion (IR5) may be provided on the outer diameter of the first carrier (C1). A fourth engagement portion (IR4) may be provided inside the case (CS).

[0077] The first meshing portion (IR) and the fourth and fifth meshing portions (IR4, IR5) may be configured with spline teeth of an internal gear. The teeth of the first meshing portion (IR) and the fourth and fifth meshing portions (IR4, IR5) may be configured in a square or trapezoidal shape while being formed at a certain interval.

[0078] The fourth coupling part (IR4) can be configured as an integral part of the case (CS) or as a separate part.

[0079] The following describes the operation of the first embodiment of the present invention in the first gear.

[0080] As shown in Fig. 1, Fig. 3 (a), Fig. 4, and Fig. 5, when shifting to the first gear, the sleeve (SL) can move in the first gear direction by the operation of the control unit (Control).

[0081] As the sleeve (SL) moves in the first gear shift direction, the first engagement portion (IR1) can be engaged with the third engagement portion (IR3) of the first ring gear (R1) and the second engagement portion (IR2) can be engaged with the fourth engagement portion (IR4) of the case (CS).

[0082] The first engagement portion (IR1) of the sleeve (SL) meshes with the third engagement portion (IR3) of the first ring gear (R1), and the second engagement portion (IR2) of the sleeve (SL) meshes with the fourth engagement portion (IR4) of the case (CS), so that the first ring gear (R1) can be fixed.

[0083] In the fixed state of the first ring gear (R1), the power of the driving motor (MG) can be transmitted to the first sun gear (S1) via the input shaft (IP).

[0084] Power transmitted to the first sun gear (S1) can be transmitted to the first carrier (C1) via the first sun gear (S1) and the first planetary gear (P1).

[0085] Since the first carrier (C1) and the second sun gear (S2) are connected, the power transmitted to the first carrier (C1) can be transmitted to the second carrier (C2) and the second ring gear (R2) via the second sun gear (S2) and the second planetary gear (P2).

[0086] Power transmitted to the second carrier (C2) can be transmitted to the intershaft (IS). The power transmitted to the intershaft (IS) can be transmitted to one drive wheel (not shown) via one axle shaft (not shown).

[0087] The second ring gear (R2) can perform the ring gear function of the second planetary gear set (PS2) and the sun gear function of the third planetary gear set (PS3). Power transmitted to the second ring gear (R2) can be transmitted to the third ring gear (R3) via the third planetary gear (P3). The third carrier (C3) is fixed to the case (CS) and cannot rotate.

[0088] Power transmitted to the third ring gear (R3) can be transmitted to the other drive wheel (not shown) via the other axle shaft (AS).

[0089] The following describes the operation of the first embodiment of the present invention in two-stage shifting.

[0090] As shown in Fig. 2, Fig. 3 (c), Fig. 4, and Fig. 5, the sleeve (SL) can move in the 2-speed shift direction by the operation of the control unit (Control) during 2-speed shifting.

[0091] As the sleeve (SL) moves in the two-speed gear direction, the first engagement portion (IR1) can be simultaneously engaged with the fifth engagement portion (IR5) of the first carrier (C1) while being engaged with the third engagement portion (IR3) of the first ring gear (R1). At the same time, the second engagement portion (IR2) can be disengaged from the fourth engagement portion (IR4).

[0092] As the second engagement portion (IR2) disengages from the fourth engagement portion (IR4), the first ring gear (R1) can rotate integrally with the first carrier (C1).

[0093] In the unlocked state of the first ring gear (R1), the power of the driving motor (MG) can be transmitted to the first sun gear (S1) via the input shaft (IP).

[0094] Power transmitted to the first sun gear (S1) can be transmitted to the first carrier (C1) via the first sun gear (S1) and the first planetary gear (P1).

[0095] Since the first carrier (C1) and the second sun gear (S2) are connected, the power transmitted to the first carrier (C1) can be transmitted to the second carrier (C2) and the second ring gear (R2) via the second sun gear (S2) and the second planetary gear (P2).

[0096] Power transmitted to the second carrier (C2) can be transmitted to the intershaft (IS). The power transmitted to the intershaft (IS) can be transmitted to one drive wheel (not shown) via one axle shaft (not shown).

[0097] The second ring gear (R2) can perform the ring gear function of the second planetary gear set (PS2) and the sun gear function of the third planetary gear set (PS3). Power transmitted to the second ring gear (R2) can be transmitted to the third ring gear (R3) via the third planetary gear (P3). The third carrier (C3) is fixed to the case (CS) and cannot rotate.

[0098] Power transmitted to the third ring gear (R3) can be transmitted to the other drive wheel (not shown) via the other axle shaft (AS).

[0099] The following describes the operation of the second embodiment of the present invention in the first gear.

[0100] As shown in (a) of Fig. 6, when the sleeve (SL) moves in the first gear shift direction, the first engagement portion (IR1) can maintain a meshing state with the third engagement portion (IR3), and the second engagement portion (IR2) can be meshed with the fourth engagement portion (IR4) provided inside the case (CS).

[0101] The following describes the operation of the second embodiment of the present invention in two-stage shifting.

[0102] As shown in (b) and (c) of FIG. 6, when the sleeve (SL) moves in the second gear shift direction during the second gear shift, the first engagement portion (IR1) maintains a meshing state with the third engagement portion (IR3), while the second engagement portion (IR2) disengages from the fourth engagement portion (IR4) and at the same time, the sixth engagement portion (IR6) can be meshed with the fifth engagement portion (IR5).

[0103] Meanwhile, the operation and power flow of the second embodiment of the present invention can be performed in the same manner as the first embodiment.

[0104] The following describes the operation of the third embodiment of the present invention in the first gear.

[0105] As shown in (a) of Fig. 7, when the sleeve (SL) moves in the first gear shift direction during the first gear shift, the first engagement portion (IR1) can be simultaneously engaged with the fourth engagement portion (IR4) while maintaining the engagement state with the third engagement portion (IR3).

[0106] The following describes the operation of the third embodiment of the present invention in two-stage shifting.

[0107] As shown in (b) and (c) of Fig. 7, as the sleeve (SL) moves in the two-stage gear shift direction, the first engagement portion (IR1) can be simultaneously engaged with the fifth engagement portion (IR5) while maintaining an engagement state with the third engagement portion (IR3).

[0108] Meanwhile, the operation and power flow of the third embodiment of the present invention can be performed in the same manner as the first embodiment.

[0109] As described above, the present invention can be easily installed in a vehicle package due to its reduction structure comprising a plurality of planetary gear sets. In addition, the present invention can perform 1-2 gear shifting, thereby enabling low-speed vehicle speed control and high-speed vehicle speed control. In addition, since the present invention is composed of a plurality of planetary gear sets, it does not take up much space when installed in a vehicle. In addition, the present invention can control the speed by the operation of the sleeve. In addition, the present invention can reduce the number of parts compared to the power transmission device of a conventional electric vehicle, thereby reducing cost, weight, and simplifying the assembly process. In addition, the present invention can be applied to both the central motor type and the electric axle type because it is composed of a module structure of a first planetary gear set, a second planetary gear set, and a third planetary gear set.

[0110] The above description is merely an illustrative description of the technical idea of ​​the present invention, and those skilled in the art will appreciate that various modifications, changes, and substitutions may be made without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention and the accompanying drawings are not intended to limit the technical idea of ​​the present invention, but rather to explain it, and the scope of the technical idea of ​​the present invention is not limited by these embodiments and the accompanying drawings. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within a scope equivalent thereto should be interpreted as being included in the scope of the rights of the present invention.

Claims

1. A first planetary gear set comprising a first sun gear coupled to an input shaft connected to a driving motor, a first ring gear configured to surround the first sun gear, a first planetary gear meshed with the first sun gear and the first ring gear between the first sun gear and the first ring gear, and a first carrier that rotatably supports the first planetary gear; A second planetary gear set comprising a second sun gear connected to the first carrier by power, a second ring gear configured to surround the second sun gear, a second planetary gear meshed with the second sun gear and the second ring gear between the second sun gear and the second ring gear, and a second carrier that supports the second planetary gear so as to be rotatable; A third planetary gear set comprising a third ring gear configured to surround the second ring gear, a third planetary gear meshed with the second ring gear and the third ring gear between the second ring gear and the third ring gear, and a third carrier that rotatably supports the third planetary gear; and A sleeve having a first engagement portion provided in the inner diameter, and wherein the first engagement portion is constantly engaged with a third engagement portion provided in the first ring gear; A power transmission device for an electric vehicle including a 2. In paragraph 1, A power transmission device for an electric vehicle, characterized in that the first planetary gear set, the second planetary gear set, and the third planetary gear set are mounted inside a case.

3. In paragraph 2, A power transmission device for an electric vehicle, characterized in that a second engagement portion is provided on the outer diameter of the sleeve, and a fifth engagement portion is provided on the outer diameter of the first carrier.

4. In paragraph 3, When shifting to 1st gear, A power transmission device for an electric vehicle, characterized in that as the sleeve moves in the first gear shift direction, the first engagement portion maintains an engagement state with the third engagement portion and the second engagement portion engages with the fourth engagement portion inside the case.

5. In paragraph 4, When shifting to 2nd gear, A power transmission device for an electric vehicle, characterized in that as the sleeve moves in the two-speed shift direction, the first engagement portion is simultaneously engaged with the fifth engagement portion while maintaining an engagement state with the third engagement portion, and the second engagement portion is separated from the fourth engagement portion.

6. In paragraph 4, The above first engagement portion and the third and fifth engagement portions are configured as spline teeth of an internal gear, A power transmission device for an electric vehicle, characterized in that the second engagement portion and the fourth engagement portion are configured with spline teeth of an internal gear.

7. In paragraph 2, A power transmission device for an electric vehicle, characterized in that a second engagement portion is provided on one side of the sleeve, a fifth engagement portion is provided on one side of the first carrier, and a sixth engagement portion is provided on the other side of the sleeve opposite to the fifth engagement portion.

8. In paragraph 7, When shifting to 1st gear, A power transmission device for an electric vehicle, characterized in that as the sleeve moves in the first gear shift direction, the first engagement portion maintains an engagement state with the third engagement portion and the second engagement portion engages with the fourth engagement portion inside the case.

9. In paragraph 8, When shifting to 2nd gear, A power transmission device for an electric vehicle, characterized in that as the sleeve moves in the two-speed shift direction, the first engagement portion maintains an engagement state with the third engagement portion, the second engagement portion disengages from the fourth engagement portion, and at the same time, the sixth engagement portion engages with the fifth engagement portion.

10. In paragraph 8, The above first engagement portion and the above third engagement portion are configured as spline teeth of an internal gear, A power transmission device for an electric vehicle, characterized in that the second engagement portion and the fourth engagement portion are configured with radial dog-type teeth facing each other, and the fifth engagement portion and the sixth engagement portion are configured with radial dog-type teeth facing each other.

11. In paragraph 2, A power transmission device for an electric vehicle, characterized in that a fifth engagement portion is provided on the outer diameter of the first carrier, and a fourth engagement portion is provided inside the case.

12. In paragraph 11, When shifting to 1st gear, A power transmission device for an electric vehicle, characterized in that as the sleeve moves in the first gear shift direction, the first engagement portion is simultaneously engaged with the fourth engagement portion while maintaining an engaged state with the third engagement portion.

13. In paragraph 12, When shifting to 2nd gear, A power transmission device for an electric vehicle, characterized in that as the sleeve moves in the two-speed shift direction, the first engagement portion is simultaneously engaged with the fifth engagement portion while maintaining an engaged state with the third engagement portion.

14. In paragraph 12, A power transmission device for an electric vehicle, characterized in that the first engagement portion and the fourth and fifth engagement portions are configured with spline teeth of an internal gear.

15. In paragraph 1, The number of the above second planetary gears is: A power transmission device for an electric vehicle, characterized in that it is configured to exceed the number of the third planetary gears.

16. In paragraph 1, A power transmission device for an electric vehicle, characterized in that the second planetary gears are arranged in six pieces along the outer diameter of the second sun gear, and the third planetary gears are arranged in five pieces along the outer diameter of the second ring gear.

17. In paragraph 2, The above third carrier is, A power transmission device for an electric vehicle, characterized in that it is fixed to the above case.

18. In paragraph 1, A power transmission device for an electric vehicle, characterized in that the power transmitted to the second carrier is transmitted to one axle shaft via an intershaft, and the power transmitted to the third ring gear is transmitted to the other axle shaft.

19. In paragraph 1, The above sleeve, A power transmission device for an electric vehicle characterized in that it can be moved in a first-speed or second-speed direction by a control unit.

Images