Two-speed electric bridge drive system and vehicle

Abstract

The present invention provides a two-speed electric axle drive system and vehicle. The transmission of this two-speed electric axle drive system includes two coaxial planetary gear mechanisms. On one hand, the sun gear shaft of the first planetary gear mechanism and the sun gear shaft of the second planetary gear mechanism are non-rotatably connected together and connected to the transmission housing via a clutch. The planetary gear carrier of the second planetary gear mechanism is connected to the transmission housing via another clutch. On the other hand, the ring gear of the first planetary gear mechanism is connected to the transmission input shaft, and the planetary gear carrier is directly connected to the transmission output shaft. The ring gear of the second planetary gear mechanism is directly connected to the transmission output shaft. Thus, by engaging and disengaging the two clutches, the transmission can transmit the torque of the power source to the differential through two drive gears. The shifting process is smooth and without power interruption, thus avoiding excessive energy consumption.

Description

Technical Field

[0001] The present invention relates to the field of vehicles, and more particularly to a two-speed electric bridge drive system and a vehicle comprising the two-speed electric bridge drive system. Background Art

[0002] Figure 1 FIG1 is a schematic diagram showing a topological structure of a two-speed electric bridge drive system, which can be used in pure electric vehicles, hybrid vehicles, etc. Figure 1 As shown, the two-speed electric axle drive system includes an electric motor (EM) and a transmission (TM). One end of the input shaft of the transmission (TM) is coupled to the rotor of the electric motor (EM) via a spline drive, for example. The other end of the input shaft of the transmission (TM) is fixedly connected to the sun gear of the planetary gear mechanism (PG) of the transmission (TM). The input shaft and the planetary gear carrier of the planetary gear mechanism (PG) are selectively drive-coupled to the differential (DM) of the transmission (TM) via a synchronizer (SN).

[0003] Although the above two-speed electric bridge drive system can achieve two-speed drive, it has the following defects:

[0004] i. During the shifting process of the transmission TM via the synchronizer SN, the motor EM exerts a large impact on the transmission TM, causing the shifting process to be uneven, thereby deteriorating the driving performance; and

[0005] ii. During the gear shifting process of the transmission TM via the synchronizer SN, power interruption occurs, resulting in additional energy loss and increased battery power consumption. Summary of the Invention

[0006] The present invention was developed in light of the aforementioned shortcomings of the two-speed electric axle drive system. One object of the present invention is to provide a novel two-speed electric axle drive system that avoids the uneven shifting and power interruption associated with synchronizer shifting. Another object of the present invention is to provide a vehicle incorporating the two-speed electric axle drive system.

[0007] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solutions.

[0008] The present invention provides a two-speed electric bridge drive system, which includes a transmission, wherein the transmission includes:

[0009] case;

[0010] Input shaft and output shaft;

[0011] a first planetary gear mechanism comprising a first sun gear, a plurality of first planet gears, a first planet gear carrier, and a first ring gear, wherein the first planet gear carrier is non-rotatably mounted on the output shaft relative to the output shaft, and the first ring gear is non-rotatably mounted on the input shaft relative to the input shaft;

[0012] a second planetary gear mechanism comprising a second sun gear, a plurality of second planet gears, a second planetary gear carrier, and a second ring gear, wherein a second sun gear shaft of the second sun gear is coaxially connected to the first sun gear shaft of the first sun gear and is non-rotatable relative to each other, and the second ring gear is non-rotatably mounted on the output shaft relative to the output shaft;

[0013] a first clutch disposed between the first sun gear shaft or the second sun gear shaft and the housing, such that the first sun gear shaft and the second sun gear shaft are fixed relative to the housing when the first clutch is engaged, and the first sun gear shaft and the second sun gear shaft are rotatable relative to the housing when the first clutch is disengaged; and

[0014] The second clutch is disposed between the second planetary carrier and the housing, so that the second planetary carrier is fixed relative to the housing when the second clutch is engaged, and the second planetary carrier is rotatable relative to the housing when the second clutch is disengaged.

[0015] Preferably, the first sun gear shaft and the second sun gear shaft are the same shaft.

[0016] More preferably, both the first sun gear shaft and the second sun gear shaft are hollow shafts, and the output shaft passes through the first sun gear shaft and the second sun gear shaft in a coaxial manner with the first sun gear shaft and the second sun gear shaft.

[0017] More preferably, the two-speed electric bridge drive system further includes a motor and a differential, the motor is drivingly connected to the input shaft, and the differential is drivingly connected to the output shaft.

[0018] More preferably, when the first clutch is engaged and the second clutch is disengaged, the torque from the motor is transmitted according to the following torque transmission path: the input shaft→the first ring gear→the plurality of first planetary gears→the first planetary gear carrier→the output shaft→the differential.

[0019] More preferably, when the first clutch is disengaged and the second clutch is engaged,

[0020] A portion of the torque from the motor is transmitted according to the following torque transmission path: the input shaft→the first ring gear→the plurality of first planetary gears→the first planetary gear carrier→the output shaft→the differential; and

[0021] Another portion of the torque from the motor is transmitted according to the following torque transmission path: the input shaft→the first ring gear→the plurality of first planetary gears→the first sun gear→the second sun gear→the plurality of second planetary gears→the second ring gear→the output shaft→the differential.

[0022] More preferably, the rotor of the motor is coaxially arranged on the input shaft, so that the input shaft always rotates with the rotor.

[0023] More preferably, the transmission further comprises an output gear disposed on the output shaft in a manner that is non-rotatable relative to the output shaft, and the differential comprises a differential input gear.

[0024] The output gear is always in meshing state with the differential input gear.

[0025] More preferably, the differential is a bevel gear differential.

[0026] The present invention also provides a vehicle as follows, comprising the two-speed electric bridge drive system described in any one of the above technical solutions.

[0027] By adopting the above technical solution, the present invention provides a two-speed electric axle drive system and a vehicle including the same. The transmission of the two-speed electric axle drive system includes two coaxial planetary gear mechanisms. On one hand, the sun gear shaft of the first planetary gear mechanism and the sun gear shaft of the second planetary gear mechanism are non-rotatably connected together and connected to the transmission housing via a clutch, and the planetary gear carrier of the second planetary gear mechanism is connected to the transmission housing via another clutch. On the other hand, the ring gear of the first planetary gear mechanism is directly connected to the input shaft of the transmission, and the planetary gear carrier is directly connected to the output shaft of the transmission, and the ring gear of the second planetary gear mechanism is connected to the output shaft of the transmission.

[0028] In this way, by engaging / disengaging the two clutches, the transmission can transmit the torque of the power source (motor) to the differential through two drive gears. In the process of the transmission shifting gears through the two clutches, the gear shifting is smooth and no power interruption occurs, thereby avoiding additional energy consumption caused by power interruption during the gear shifting process. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1The figure shows a topological structure diagram of a two-speed electric bridge drive system.

[0030] Figure 2 FIG. 1 is a schematic diagram showing the topological structure of a two-speed electric bridge drive system according to an embodiment of the present invention.

[0031] Description of Reference Numerals

[0032] EM motor TM transmission PG planetary gear mechanism SN synchronizer

[0033] S1 Input shaft S2 Output shaft S3 Sun gear shaft SU1 First sun gear PL1 First planetary gear P1 First planetary gear carrier R1 First ring gear SU2 Second sun gear PL2 Second planetary gear P2 Second planetary gear carrier R2 Second ring gear G1 Output gear C1 First clutch C2 Second clutch

[0034] DM differential G2 differential input gear. DETAILED DESCRIPTION

[0035] The following describes exemplary embodiments of the present invention with reference to the accompanying drawings. It should be understood that these specific descriptions are only used to teach those skilled in the art how to implement the present invention, and are not intended to exhaust all possible embodiments of the present invention, nor to limit the scope of the present invention.

[0036] In the present invention, "transmission connection" refers to the connection between two components that can transmit driving force / torque. Unless otherwise specified, it can mean that the two components are directly connected or connected via a gear mechanism, etc. to enable driving force / torque to be transmitted between the two components.

[0037] Figure 2 1 is a schematic diagram showing the topological structure of a two-speed electric bridge drive system according to an embodiment of the present invention. Figure 2 As shown, a two-speed electric bridge drive system according to an embodiment of the present invention includes a motor EM, a transmission and a differential DM.

[0038] In this embodiment, the motor EM includes a stator and a rotor located radially inside the stator and rotatable relative to the stator.

[0039] In the present embodiment, the transmission includes an input shaft S1 , an output shaft S2 , two planetary gear mechanisms (a first planetary gear mechanism and a second coaxial planetary gear mechanism), and two clutches (a first clutch C1 and a second clutch C2 ).

[0040] Specifically, the transmission's input shaft S1 is coaxially drivingly coupled to the rotor of the electric motor EM, enabling input shaft S1 to rotate with the rotor and transmitting torque from the rotor of the electric motor EM to the transmission via input shaft S1. The transmission's output shaft S2 is drivingly coupled to the differential DM via a set of gear pairs, allowing torque from the transmission to be transmitted to the differential DM via output shaft S2.

[0041] Furthermore, the first planetary gear mechanism includes a first sun gear SU1, multiple first planetary gears PL1, a first planetary gear carrier P1, and a first ring gear R1. The first sun gear SU1 is constantly meshed with the multiple first planetary gears PL1 located radially outward from the first sun gear SU1. The multiple first planetary gears PL1 are constantly meshed with the first ring gear R1 located radially outward from the first sun gear SU1. The multiple first planetary gears PL1 are mounted on the first planetary gear carrier P1. Furthermore, the first planetary gear carrier P1 is fixedly mounted on the output shaft S2 so that it can rotate with the output shaft S2. The first ring gear R1 is fixedly mounted on the input shaft S1 so that it can rotate with the input shaft S1.

[0042] The second planetary gear mechanism is coaxially arranged with the first planetary gear mechanism and includes a second sun gear SU2, multiple second planetary gears PL2, a second planetary carrier P2, and a second ring gear R2. The second sun gear SU2 is constantly meshed with the multiple second planetary gears PL2 located radially outward from the second sun gear SU2. The multiple second planetary gears PL2 are constantly meshed with the second ring gear R2 located radially outward from the second sun gear SU2. The multiple second planetary gears PL2 are mounted on the second planetary carrier P2. Furthermore, the second sun gear SU2 and the first sun gear SU1 share a common sun gear shaft S3. The second ring gear R2 is fixed to the output shaft S2 so that it can rotate with the output shaft S2.

[0043] Furthermore, the transmission features a first clutch C1 and a second clutch C2 to achieve two-speed drive. The first clutch C1 is positioned between the sun gear shaft S3 and the transmission housing. When the first clutch C1 is engaged, the sun gear shaft S3 is fixed relative to the transmission housing. When the first clutch C1 is disengaged, the sun gear shaft S3 is able to rotate relative to the transmission housing. The second clutch C2 is positioned between the second planetary carrier P2 and the transmission housing. When the second clutch C2 is engaged, the second planetary carrier P2 is fixed relative to the transmission housing. When the second clutch C2 is disengaged, the second planetary carrier P2 is able to rotate relative to the transmission housing.

[0044] In this embodiment, the differential DM is, for example, a bevel gear differential. This bevel gear differential includes a differential input gear G2. The transmission also includes an output gear G1, which is fixedly mounted on the transmission output shaft S2 so as to be non-rotatable relative to the transmission output shaft S2. The differential input gear G2 and the output gear G1 are constantly engaged. Thus, via this gear pair (gears G1 and G2), the transmission can transmit torque to the differential DM.

[0045] When the two-speed electric axle drive system according to an embodiment of the present invention adopts the above-described structure, torque can be transmitted through the following paths.

[0046] Specifically, when the first clutch C1 is engaged and the second clutch C2 is disengaged, the torque from the motor is transmitted along the following torque transmission path: input shaft S1 → first ring gear R1 → multiple first planetary gears PL1 → first planetary carrier P1 → output shaft S2 → differential DM.

[0047] When the first clutch C1 is disengaged and the second clutch C2 is engaged, part of the torque from the motor is transmitted according to the following torque transmission path: input shaft S1 → first ring gear R1 → multiple first planetary gears PL1 → first planetary gear carrier P1 → output shaft S2 → differential DM; and another part of the torque from the motor is transmitted according to the following torque transmission path: input shaft S1 → first ring gear R1 → multiple first planetary gears PL1 → first sun gear SU1 → second sun gear SU2 → multiple second planetary gears PL2 → second ring gear R2 → output shaft S2 → differential DM.

[0048] In addition, the present invention also provides a vehicle including a two-speed electric bridge drive system having the above structure. The vehicle can be a pure electric vehicle or a hybrid vehicle.

[0049] The technical solution of the present invention has been described in detail in the above specific embodiments, and supplementary explanations are given below.

[0050] i. In the two-speed electric bridge drive system of the present invention, a single clutch C1, C2 can achieve a gear, thereby realizing a two-speed electric bridge drive system, and thus Figure 1 Compared with the two-speed electric bridge drive system in the vehicle, the synchronizer is omitted and a higher transmission ratio is achieved in a smaller space.

[0051] Furthermore, in the two-speed electric bridge drive system of the present invention, since gear shifting is performed through the clutches C1 and C2 instead of synchronizers, smooth gear shifting is achieved and driving performance is improved.

[0052] Furthermore, since the clutches C1 and C2 can achieve sliding engagement when the system is overloaded, other components of the system are prevented from being subjected to excessive impact when the system is overloaded.

[0053] Furthermore, in the two-speed electric bridge drive system of the present invention, the NVH performance of the transmission is improved and the service life of the vehicle is increased.

[0054] ii. Although not described in the above specific embodiments, Figure 2 As shown, the sun gear shaft S3 may be a hollow shaft, and the output shaft S2 passes through the sun gear shaft S3 in a coaxial manner with the sun gear shaft S3 .

[0055] iii. The specific structures of clutches C1 and C2 are not described in the above embodiments. Preferably, clutches C1 and C2 can be dry friction clutches, which are low-cost and do not require replacement during their service life. However, the present invention is not limited thereto, and clutches C1 and C2 can also be other types of clutches.

Claims

1. A two-speed electric bridge drive system, comprising a transmission, the transmission comprising: case; Input shaft (S1) and output shaft (S2); a first planetary gear mechanism comprising a first sun gear (SU1), a plurality of first planetary gears (PL1), a first planetary gear carrier (P1), and a first ring gear (R1), wherein the first planetary gear carrier (P1) is arranged on the output shaft (S2) in a manner that is non-rotatable relative to the output shaft (S2), and the first ring gear (R1) is arranged on the input shaft (S1) in a manner that is non-rotatable relative to the input shaft (S1); a second planetary gear mechanism comprising a second sun gear (SU2), a plurality of second planetary gears (PL2), a second planetary gear carrier (P2), and a second ring gear (R2); a second sun gear shaft of the second sun gear (SU2) and a first sun gear shaft of the first sun gear (SU1) being coaxially connected to each other and non-rotatable relative to each other; and the second ring gear (R2) being disposed on the output shaft (S2) in a non-rotatable manner relative to the output shaft (S2); a first clutch (C1) disposed between the first sun gear shaft or the second sun gear shaft and the housing, such that the first sun gear shaft and the second sun gear shaft are fixed relative to the housing when the first clutch (C1) is engaged, and the first sun gear shaft and the second sun gear shaft are rotatable relative to the housing when the first clutch (C1) is disengaged; and A second clutch (C2) is arranged between the second planetary gear carrier (P2) and the housing, so that when the second clutch (C2) is engaged, the second planetary gear carrier (P2) is fixed relative to the housing, and when the second clutch (C2) is disengaged, the second planetary gear carrier (P2) can rotate relative to the housing.

2. The two-speed electric bridge drive system according to claim 1, characterized in that: The first sun gear shaft and the second sun gear shaft are the same shaft (S3).

3. The two-speed electric bridge drive system according to claim 1, characterized in that: The first sun gear shaft and the second sun gear shaft are both hollow shafts, and the output shaft (S2) passes through the first sun gear shaft and the second sun gear shaft in a coaxial manner with the first sun gear shaft and the second sun gear shaft.

4. The two-speed electric bridge drive system according to any one of claims 1 to 3, characterized in that: The two-speed electric bridge drive system further comprises an electric motor (EM) and a differential (DM), wherein the electric motor (EM) is drivingly connected to the input shaft (S1), and the differential (DM) is drivingly connected to the output shaft (S2).

5. The two-speed electric bridge drive system according to claim 4, characterized in that: When the first clutch (C1) is engaged and the second clutch (C2) is disengaged, torque from the electric motor (EM) is transmitted according to the following torque transmission path: the input shaft (S1) → the first ring gear (R1) → the plurality of first planetary gears (PL1) → the first planetary gear carrier (P1) → the output shaft (S2) → the differential (DM).

6. The two-speed electric bridge drive system according to claim 4, characterized in that: When the first clutch (C1) is disengaged and the second clutch (C2) is engaged, A portion of the torque from the electric motor (EM) is transmitted according to the following torque transmission path: the input shaft (S1) → the first ring gear (R1) → the plurality of first planetary gears (PL1) → the first planetary gear carrier (P1) → the output shaft (S2) → the differential (DM); and Another portion of the torque from the electric motor (EM) is transmitted according to the following torque transmission path: the input shaft (S1) → the first ring gear (R1) → the plurality of first planetary gears (PL1) → the first sun gear (SU1) → the second sun gear (SU2) → the plurality of second planetary gears (PL2) → the second ring gear (R2) → the output shaft (S2) → the differential (DM).

7. The two-speed electric bridge drive system according to claim 4, characterized in that: The rotor of the electric motor (EM) is coaxially arranged on the input shaft (S1), so that the input shaft (S1) always rotates with the rotor.

8. The two-speed electric bridge drive system according to claim 4, characterized in that: The transmission further includes an output gear (G1) arranged on the output shaft (S2) in a manner that is non-rotatable relative to the output shaft (S2); the differential (DM) includes a differential input gear (G2); and the output gear (G1) and the differential input gear (G2) are always in a meshing state.

9. The two-speed electric bridge drive system according to claim 8, characterized in that: The differential (DM) is a bevel gear differential.

10. A vehicle, characterized in that: The vehicle comprises the two-speed electric axle drive system according to any one of claims 1 to 9.

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