WO2023137661A1

WO2023137661A1 - Electric axle drive system and vehicle

Info

Publication number: WO2023137661A1
Application number: PCT/CN2022/072972
Authority: WO
Inventors: 俞正才
Original assignee: 舍弗勒技术股份两合公司; 俞正才
Priority date: 2022-01-20
Filing date: 2022-01-20
Publication date: 2023-07-27

Abstract

an electric axle drive system is provided, which comprises a motor (EM) and a transmission; the transmission comprises an input shaft (S1), a first intermediate shaft (S2) and a differential (DM); the input shaft (S1) establishes a continuous transmission connection with a rotor of the motor (EM); the first intermediate shaft (S2) establishes a transmission connection with the input shaft (S1), and the differential (DM) establishes a transmission connection with the first intermediate shaft (S2) via an internally meshing gear pair. As a consequence, the transmission ratio can be increased without increasing the overall packaging size of an electric axle drive system. A vehicle comprising the electric axle drive system is further provided.

Description

Bridge drive system and vehicle

technical field

The present application relates to the field of vehicles, and more specifically relates to a vehicle bridge drive system and a vehicle including the bridge drive system.

Background technique

Currently, the bridge drive system can be used in pure electric vehicles and hybrid vehicles to propel the vehicles.

Figure 1 shows a bridge drive system. As shown in FIG. 1 , the bridge drive system includes a motor EM, a transmission and two half shafts (first half shaft HS1 and second half shaft HS2 ). The motor EM includes components such as a rotor and a stator, and is used to transmit torque to the transmission. The transmission transmits the torque from the motor EM to the wheels via the first half shaft HS1 and the second half shaft HS2 to drive the vehicle.

The transmission includes an input shaft S1, an intermediate shaft S2, a differential DM, and a plurality of gears G1-G4. Specifically, the input shaft S1 can be drivingly coupled with the rotor of the electric machine EM. The intermediate shaft S2 is arranged parallel to and staggered with the input shaft S1 (non-coaxial arrangement). The differential DM is a conventional bevel gear differential. The two half shafts HS1, HS2 are coaxially arranged with the input shaft S1, and the two half shafts HS1, HS2 extend from the differential DM toward both sides of the differential DM.

The gear G4 is provided on the input shaft S1 in a manner to resist torsion with the input shaft S1, so that the gear G4 can always rotate with the input shaft S1. Both the gear G1 and the gear G3 are arranged on the intermediate shaft S2 in a manner to resist rotation with the intermediate shaft S2, so that the gear G1 and the gear G3 can always rotate with the intermediate shaft S2. The gear G2 is the input gear of the differential DM, and can be fixed together with the housing of the differential DM. Further, the gear G4 and the gear G3 are always in a meshing state to form an external meshing gear pair; the gear G1 and the gear G2 are always in a meshing state to form an external meshing gear pair. In this way, the transmission path of the torque from the motor EM is as follows: motor EM→input shaft S1→gear G4→gear G3→intermediate shaft S2→gear G1→gear G2→differential DM→two half shafts HS1, HS2.

Since the transmission ratio of the entire electric bridge drive system is mainly set by the gear pair formed by the gear G4 and the gear G3 and the gear pair formed by the gear G1 and the gear G2, the above electric bridge drive system has the following defects. Since these two gear pairs are external gear pairs, if the transmission ratio needs to be increased, the distance between the input shaft S1 and the intermediate shaft S2 needs to be increased, resulting in a corresponding increase in the overall packaging size of the entire bridge drive system.

Contents of the invention

The present application is made in view of the defects existing in the above-mentioned technologies. An object of the present application is to provide a novel bridge drive system capable of increasing the transmission ratio without increasing the package size of the bridge drive system. Another object of the present application is to provide a vehicle including the above-mentioned bridge drive system.

In order to achieve the above purpose, the present application adopts the following technical solutions.

The present application provides a bridge drive system as follows, which includes a motor and a transmission, and the transmission includes:

an input shaft, which is always drivingly coupled with the rotor of the motor;

a first countershaft offset parallel to the input shaft and drivingly coupled to the input shaft; and

a differential gear, which is drivingly coupled with the first countershaft via an internally meshed gear pair.

In an optional technical solution, the transmission further includes a first intermediate gear, the first intermediate gear is arranged on the first intermediate shaft in a torque-resistant manner, and the differential includes a differential input gear,

The first intermediate gear is an external gear, the differential input gear is an internal gear, and the first intermediate gear is always in mesh with the differential input gear.

In another optional technical solution, the transmission further includes a second intermediate gear and an input gear, the second intermediate gear is arranged on the first intermediate shaft in a torque-resistant manner, and the input gear is arranged on the input shaft in a torque-resistant manner,

Both the second intermediate gear and the input gear are external gears, and the second intermediate gear is always in mesh with the input gear.

In another optional technical solution, the transmission further includes a first countershaft bearing supporting the countershaft, and the first countershaft bearing is located between the first counter gear and the second counter gear.

In another optional technical solution, the transmission further includes a second countershaft bearing supporting the countershaft, and the second countershaft bearing and the first countershaft bearing are located on both axial sides of the second counter gear.

In another optional technical solution, the transmission further includes a first differential bearing supporting the differential,

In the axial direction of the input shaft, the first differential bearing and the first intermediate shaft bearing are located at the same position.

In another optional technical solution, the transmission further includes a second countershaft, the second countershaft is parallel to the input shaft and the first input shaft and is staggered, and the input shaft is drive-coupled to the first countershaft via the second countershaft.

In another optional technical solution, the bridge drive system further includes a first half shaft and a second half shaft protruding from the differential, the first half shaft extends through the input shaft and the motor coaxially with the input shaft, and the second half shaft extends in a direction opposite to the extension direction of the first half shaft coaxially with the first half shaft.

In another optional technical solution, the differential is a bevel gear differential.

The present application also provides a vehicle as follows, which includes the bridge drive system described in any one of the above technical solutions.

By adopting the above technical solution, the present application provides a novel electric bridge drive system, the differential and the intermediate shaft of the electric bridge drive system realize the transmission connection through the internally meshed gear pair, so that the transmission ratio can be increased without increasing the overall package size of the electric bridge drive system. The present application also provides a vehicle comprising the above-mentioned bridge drive system.

Description of drawings

FIG. 1 is a schematic topology diagram showing the structure of a bridge drive system.

FIG. 2 is a schematic topology diagram showing the structure of a bridge driving system according to an embodiment of the present application.

Explanation of reference signs

EM motor HS1 first half shaft HS2 second half shaft

S1 input shaft S2 intermediate shaft DM differential G1, G2, G3, G4 gears G11 input gear G21 first intermediate gear G22 second intermediate gear G31 differential input gear B1 first intermediate shaft bearing B2 second intermediate shaft bearing B3 first differential bearing B4 second differential bearing B5 input shaft bearing.

Detailed ways

Exemplary embodiments of the present application are described below 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 application, but are not intended to exhaust all possible ways of the present application, nor are they used to limit the scope of the present application.

In this application, "drive coupling" means that two components are connected in a torque-transmittable manner. The two parts can be connected directly or indirectly to be able to transmit torque between the two parts.

In this application, "torque-resistant" means that two parts are capable of transmitting torque between them and are capable of turning together. For example, when a gear is provided on a shaft in a torque-resistant manner, torque can be transmitted between the gear and the shaft, and the gear can rotate together with the shaft.

In this application, unless otherwise specified, “axial” refers to the axial direction of the transmission input shaft, “one side of the axial direction” refers to the right side in FIG. 2 , and “the other side of the axial direction” refers to the left side in FIG. 2 .

A bridge driving system according to an embodiment of the present application will be described below with reference to the accompanying drawings.

As shown in FIG. 2 , the bridge drive system according to an embodiment of the present application includes an integrated motor EM, a transmission, and two half shafts (first half shaft HS1 and second half shaft HS2 ).

In this embodiment, the motor EM includes components such as a rotor and a stator housed in the motor housing to generate torque for driving. The entire transmission is located on one side in the axial direction of the motor EM and housed in the transmission case. The transmission includes an input shaft S1, an intermediate shaft (first intermediate shaft) S2, a differential DM, and gears G11, G21, G22, and G31 provided on the respective shafts and the differential DM.

In this embodiment, the input shaft S1 is drivingly coupled with the rotor of the electric motor EM, so that the transmission can receive torque from the electric motor EM. Specifically, the input shaft S1 can be used as the output shaft of the motor EM, or the input shaft S1 can be rigidly connected with the output shaft of the motor EM in a coaxial manner through a coupling. The input shaft S1 is formed as a hollow shaft linearly extending in the axial direction so that the first half shaft HS1 is inserted therethrough. The intermediate shaft S2 is arranged parallel to and offset from the input shaft S1 (non-coaxial arrangement). The intermediate shaft S2 may be formed as a solid shaft linearly extending in the axial direction. The differential DM may be a bevel gear differential and the differential DM is located at one axial side of the transmission input shaft. The two half shafts HS1 and HS2 extend from the differential DM toward both axial sides of the differential DM, and are used to transmit torque to the wheels of the vehicle. The first half-shaft HS1 protrudes from the differential DM toward the other axial side in a coaxial manner with the input shaft S1, passes through the inside of the input shaft S1 and passes through the motor EM, and the second half-shaft HS2 extends in a direction opposite to the protruding direction of the first half-shaft HS1, that is, toward one axial side in a coaxial manner with the first half-shaft HS1.

In this embodiment, the input gear G11 is provided on the input shaft S1 in a torsion-resistant manner, so that the input gear G11 can rotate together with the input shaft S1. The first intermediate gear G21 is arranged in a torque-proof manner on the intermediate shaft S2, and the second intermediate gear G22 is arranged in a rotationally fixed manner on the intermediate shaft S2. The differential input gear G31 may be fixed to the case of the differential DM. Further, the input gear G11 and the second intermediate gear G22 are always in meshing state, both the input gear G11 and the second intermediate gear G22 are external gears, and they form an externally meshing gear pair. The diameter of the input gear G11 is smaller than that of the second intermediate gear G22. The first intermediate gear G21 and the transmission input gear G31 are always in meshing state, the first intermediate gear G21 is an external gear, and the transmission input gear G31 is an internal gear, and the two constitute an internal meshing gear pair. The diameter of the first intermediate gear G21 is smaller than that of the transmission input gear G31. In this way, the transmission can change the transmission ratio by adjusting the above two gear pairs. Moreover, when it is necessary to increase the transmission ratio of the entire transmission, it can be achieved by adjusting the structure of the internal meshing gear pair formed by the first intermediate gear G21 and the transmission input gear G31 (for example, reducing the diameter of the first intermediate gear G21), so that the transmission ratio can be increased without increasing the distance between the input shaft S1 and the intermediate shaft S2. Compared with the electric bridge drive system described in the background art, a larger transmission ratio can be realized with the same package size, and a smaller package size can be realized with the same transmission ratio.

Therefore, in this embodiment, the transmission path of the torque from the motor EM is as follows: motor EM → input shaft S1 → input gear G11 → second intermediate gear G22 → intermediate shaft S2 → first intermediate gear G21 → differential input gear G31 → differential DM → two half shafts HS1, HS2.

Further, in order to support the countershaft S2, the transmission may further include a first countershaft bearing B1 and a second countershaft bearing B2 that are separated. The first countershaft bearing B1 is located between the first counter gear G21 and the second counter gear G22, and the second counter shaft bearing B2 is located on the other axial side of the second counter gear G22, so that the second counter shaft bearing B2 and the first counter shaft bearing B1 are located on both axial sides of the second counter gear G22. In order to support the case of the differential DM, the transmission may further include a first differential bearing B3 and a second differential bearing B4 that are separated, the first differential bearing B3 being located on the other side in the axial direction of the second differential bearing B4. Moreover, the first differential bearing B3 and the first intermediate shaft bearing B1 can be located at the same position in the axial direction, which is beneficial to reduce the axial length of the entire bridge drive system. In order to support the input shaft S1, the transmission may further include an input shaft bearing B5.

Further, in order to install the electric motor EM and various components of the transmission, the housing of the entire bridge drive system may be composed of three housing parts that can be detachably connected to each other. The motor housing for receiving the electric motor is formed from a first housing part and a second housing part, which also serves as part of the transmission housing of the transmission. The transmission housing is formed from a second housing part and a third housing part. The above-mentioned bearings B1, B2, B3, B4, B5 are respectively arranged on corresponding housing parts.

The technical solutions of the present application have been described in detail in the above content, and supplementary explanations are given below.

i. It should be understood that in the electric bridge drive system of the present application, in addition to outputting torque for driving to the transmission, the motor EM can also receive torque from the engine, or receive torque from the transmission (for example, perform braking energy recovery), and then drive the vehicle or charge the battery.

ii. It can be understood that in the electric bridge drive system of the present application, the transmission can also include a second countershaft, the second countershaft is arranged parallel to the input shaft S1 and the first countershaft S2, and the input shaft S1 is always drivingly coupled with the first countershaft S2 via the second countershaft. In this way, when the second countershaft is arranged in a staggered manner from the first countershaft S2 and the input shaft S1, the transmission ratio of the transmission can be further increased through the gear pair formed by the gears provided on the second countershaft, the gears provided on the input shaft S1 and the gears provided on the first countershaft S2, without significantly increasing or even increasing the package size of the entire bridge drive system.

iii. It can be understood that, compared with the bridge drive system described in the background art, the overall package size of the bridge drive system of the present application is smaller when the same transmission ratio is achieved; while the bridge drive system of the present application can achieve a larger transmission ratio with the same package size.

iv. This application can easily realize the support of the bearings of the bridge drive system.

v. The present application also provides a vehicle including the above bridge drive system, the vehicle may be a pure electric vehicle or a hybrid vehicle.

Claims

An electric bridge drive system comprising an electric machine (EM) and a transmission comprising:

an input shaft (S1), which is always drivingly coupled with the rotor of said electric machine (EM);

a first intermediate shaft (S2), which is arranged parallel to the input shaft (S1) and staggered, and is drivingly coupled with the input shaft (S1); and

A differential (DM), which is coupled with the first countershaft (S2) via an internally meshed gear pair.
The electric bridge drive system according to claim 1, characterized in that, the transmission further comprises a first intermediate gear (G21), the first intermediate gear (G21) is arranged on the first intermediate shaft (S2) in a torque-resistant manner, the differential (DM) comprises a differential input gear (G31),

The first intermediate gear (G21) is an external gear, the differential input gear (G31) is an internal gear, and the first intermediate gear (G21) is always in meshing state with the differential input gear (G31).
The bridge drive system according to claim 1 or 2, characterized in that the transmission further comprises a second intermediate gear (G22) and an input gear (G11), the second intermediate gear (G22) is arranged on the first intermediate shaft (S2) in a torque-resistant manner, and the input gear (G11) is arranged on the input shaft (S1) in a torque-resistant manner,

Both the second intermediate gear (G22) and the input gear (G11) are external gears, and the second intermediate gear (G22) and the input gear (G11) are always in meshing state.
The electric bridge drive system according to claim 3, characterized in that, the transmission further comprises a first countershaft bearing (B1) supporting the countershaft (S2), and the first countershaft bearing (B1) is located between the first counter gear (G21) and the second counter gear (G22).
The electric bridge drive system according to claim 4, characterized in that the transmission further comprises a second countershaft bearing (B2) supporting the countershaft (S2), the second countershaft bearing (B2) and the first countershaft bearing (B1) are located on both axial sides of the second counter gear (G22).
The bridge drive system according to claim 4 or 5, characterized in that the transmission further comprises a first differential bearing (B3) supporting the differential (DM),

In the axial direction of the input shaft (S1), the first differential bearing (B3) and the first intermediate shaft bearing (B1) are located at the same position.
The electric bridge drive system according to claim 1 or 2, characterized in that the transmission further comprises a second intermediate shaft (S2), the second intermediate shaft (S2) is arranged in a staggered manner parallel to the input shaft (S1) and the first input shaft (S2), and the input shaft (S1) is drivingly coupled to the first intermediate shaft (S2) via the second intermediate shaft (S2).
The electric bridge driving system according to any one of claims 1 to 7, characterized in that, the electric bridge driving system further comprises a first half shaft (HS1) and a second half shaft (HS2) protruding from the differential (DM), the first half shaft (HS1) extends through the input shaft (S1) and the electric motor (EM) coaxially with the input shaft (S1), and the second half shaft (HS2) faces toward the side of the first half shaft (HS1) in a coaxial manner with the first half shaft (HS1) The direction opposite to the direction of extension extends.
The bridge drive system according to any one of claims 1 to 8, characterized in that the differential (DM) is a bevel gear differential.
A vehicle comprising the bridge drive system according to any one of claims 1 to 9.