Bridge driving system and vehicle

Abstract

The invention provides a bridge driving system and a vehicle. The electric bridge driving system comprises two electric bridge driving units which are coaxially arranged. Each bridge driving unit comprises a motor and a transmission which are coaxially arranged. Further, the transmission comprises two planet rows, and at least one part of the transmission is overlapped with the motor in the axial direction of the bridge driving system. Therefore, the overall axial size of the bridge driving system can be reduced, the space occupied by the whole bridge driving system is saved, and the structural layout of the vehicle comprising the bridge driving system is facilitated. Besides, the power source of the transmission in each bridge driving unit transmits torque to the outside through the two planet rows, so that a torque transmission path with a large transmission ratio can be realized by a relatively compact structure, the torque demand on the motor is reduced, and the cost of the motor can be correspondingly saved.

Description

Technical Field

[0001] The present application relates to the field of vehicles, and more specifically to an electric bridge drive system for a vehicle and a vehicle including the electric bridge drive system. Background Art

[0002] At present, the electric bridge drive system can be used for pure electric vehicles and hybrid vehicles to drive the vehicle. In a typical electric bridge drive system, two coaxially arranged motors are included as power sources, which can improve the dynamic performance of the vehicle (for example, the acceleration time from starting to 100 km / h). Furthermore, in the above-mentioned electric bridge drive system, transmissions are respectively provided for the two motors, so that the motors can drive the wheels of the vehicle via the corresponding transmissions. However, when the transmission has a sufficiently large transmission ratio, the axial dimension of the electric bridge drive system is large and the space occupied is large, which has an adverse effect on the overall layout of the vehicle including the electric bridge drive system. Summary of the invention

[0003] This application is made in view of the defects in the above-mentioned technology. One object of this application is to provide a new type of electric bridge drive system, which can improve the transmission ratio while reducing the axial size of the electric bridge drive system. Another object of this application is to provide a vehicle including the above-mentioned electric bridge drive system.

[0004] In order to achieve the above objectives, this application adopts the following technical solutions.

[0005] The present application provides the following electric bridge drive system, comprising two coaxially arranged electric bridge drive units, each electric bridge drive unit comprising a motor and a transmission, the transmission being coaxially arranged with the motor, at least a portion of the transmission overlapping with the motor in the axial direction of the electric bridge drive system,

[0006] The motor includes a rotor and a stator, and the transmission includes a first planetary row and a second planetary row, the first planetary row includes a first sun gear, a plurality of first planetary gears, a first planetary wheel carrier and a first ring gear assembled together, the first sun gear is connected to the rotor to achieve transmission connection, and the first ring gear is fixed relative to the stator, and the second planetary row includes a second sun gear, a plurality of second planetary gears, a second planetary wheel carrier and a second ring gear assembled together, the second sun gear is connected to the first planetary wheel carrier to achieve transmission connection, and the second ring gear is fixed relative to the stator, thereby enabling the torque from the rotor to be output to the outside via the second planetary wheel carrier.

[0007] In an optional solution, for one of the two electric bridge drive units, the transmission is located at one axial end of the motor; and for the other electric bridge drive unit of the two electric bridge drive units, the transmission is located at the other axial end of the motor.

[0008] In another optional scheme, the stator includes an iron core and a winding, the winding includes a protruding portion extending from the iron core, the first planetary row is located radially inside the protruding portion, and at least a portion of the first planetary row overlaps with the protruding portion in the axial direction.

[0009] In another optional solution, the second planetary gear and the motor are offset in the axial direction.

[0010] In another optional solution, the first planetary gear row is located in the rotor and the first planetary wheel carrier extends from the rotor along the axial direction.

[0011] In another optional scheme, the stator includes an iron core and a winding, the winding includes a protruding portion extending from the iron core, the second planetary row is located radially inside the protruding portion, and at least a portion of the second planetary row overlaps with the protruding portion in the axial direction.

[0012] In another optional solution, the electric bridge drive unit includes a housing, and the ring gear is fixed to the housing.

[0013] In another optional solution, the electric bridge drive unit includes a plurality of bearings mounted on the housing, and the plurality of bearings are used to support the first planetary wheel carrier and the second planetary wheel carrier so that the first planetary wheel carrier and the second planetary wheel carrier can rotate relative to the housing.

[0014] The present application also provides a vehicle as follows, comprising the electric bridge drive system described in any one of the above technical solutions.

[0015] In an optional solution, the first wheel and the second wheel are further included, wherein the first wheel and the second wheel are respectively connected to two electric bridge drive units of the electric bridge drive system through transmission.

[0016] The first wheel and the second wheel are both front wheels or the first wheel and the second wheel are both rear wheels.

[0017] By adopting the above technical solution, the present application provides a novel electric bridge drive system and a vehicle including the electric bridge drive system. The electric bridge drive system of the present application includes two coaxially arranged electric bridge drive units. Each electric bridge drive unit includes a coaxially arranged motor and a transmission. Further, at least a part of the transmission overlaps with the motor in the axial direction of the electric bridge drive system. The transmission includes a first planetary row and a second planetary row. The first planetary row includes a first sun gear, a plurality of first planetary gears, a first planetary wheel carrier and a first gear ring assembled together, the first sun gear is connected to the rotor of the motor to achieve transmission connection, and the first gear ring is fixed relative to the stator. The second planetary row includes a second sun gear, a plurality of second planetary gears, a second planetary wheel carrier and a second gear ring assembled together, the second sun gear is connected to the first planetary wheel carrier to achieve transmission connection, and the second gear ring is fixed relative to the stator. As a result, the torque from the rotor can be output to the outside via the second planetary wheel carrier.

[0018] Thus, on the one hand, since at least a part of the transmission in each electric bridge drive unit overlaps with the motor in the axial direction of the electric bridge drive system, the overall axial dimension of the electric bridge drive system can be reduced, saving the space occupied by the entire electric bridge drive system, which is beneficial to the structural layout of the vehicle including the electric bridge drive system. On the other hand, since the power source of the transmission in each electric bridge drive unit transmits torque to the outside via two planetary gears, a torque transmission path with a large transmission ratio can be realized with a relatively compact structure, thereby reducing the torque demand on the motor and saving the cost of the motor accordingly. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram showing the topological structure of the electric bridge drive system according to the first embodiment of the present application.

[0020] Figure 2 is a schematic diagram showing a topological structure of an electric bridge drive system according to a second embodiment of the present application.

[0021] Description of Reference Numerals

[0022] EU bridge drive unit;H housing;

[0023] EM motor; RO rotor; S1 rotor shaft; ST stator; IC core; WI winding;

[0024] TM transmission; SG1 first sun gear; PG1 first planetary gear; PC1 first planetary gear carrier; RG1 first ring gear; SG2 second sun gear; PG2 second planetary gear; PC2 second planetary gear carrier; RG2 second ring gear; S2 output shaft;

[0025] A is axial; R is radial. DETAILED DESCRIPTION

[0026] The 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, and are not intended to exhaust all feasible methods of the present application, nor to limit the scope of the present application.

[0027] In the present application, unless otherwise specified, "drive connection" refers to a connection between two components that can transmit torque, including direct connection and indirect connection.

[0028] In this application, unless otherwise specified, "axial" and "radial" refer to the axial and radial directions of the bridge drive unit (motor), respectively. "Axial side" refers to Figure 1 and Figure 2 The left side of the axis refers to Figure 1 and Figure 2 The “radially inner side” refers to the side close to the central axis of the bridge drive unit (motor), and the “radially outer side” refers to the side away from the central axis of the bridge drive unit (motor).

[0029] An electric bridge drive system and a vehicle including the electric bridge drive system according to a first embodiment of the present application will be described below in conjunction with the accompanying drawings.

[0030] (Electric bridge drive system and vehicle according to the first embodiment of the present application)

[0031] like Figure 1 As shown, the electric bridge drive system according to the first embodiment of the present application includes two electric bridge drive units EU integrated together. Each electric bridge drive unit EU includes a motor EM, a transmission TM and a housing H, and the motor EM and the transmission TM are both received and installed in the corresponding housing H. Figure 1 As shown, the two electric bridge drive units EU are coaxially arranged side by side, and in each electric bridge drive unit EU, the motor EM and the transmission TM are coaxially arranged. Further, in the structural layout of the entire electric bridge drive system, one electric bridge drive unit EU is located as a whole on one axial side of the other electric bridge drive unit EU. In the above-mentioned one electric bridge drive unit EU, the transmission TM is located at one axial end of the motor EM; in the above-mentioned other electric bridge drive unit EU, the transmission TM is located at the other axial end of the motor EM. In this embodiment, the structures of the two electric bridge drive units EU are arranged basically linearly symmetrically with respect to the center line of the electric bridge drive system at the axial center.

[0032] In this embodiment, if Figure 1As shown, the motor EM includes a stator ST and a rotor RO located inside the stator ST and capable of rotating relative to the stator ST. Specifically, the stator ST includes an iron core IC and a winding WI. The iron core IC can be made of stacked silicon steel sheets and is formed with a plurality of slots for inserting and installing the winding WI. The winding WI is inserted into the plurality of slots of the iron core IC and wound and installed on the iron core IC. A portion of the winding WI can extend from both axial ends of the iron core IC to form an extended portion. In the rotor RO, the rotor shaft S1 is fixed to the rotor stack so that the rotor shaft S1 can rotate with the rotor stack. The rotor shaft S1 is formed to extend in a straight line along the axial direction A. In addition, the rotor shaft S1 is directly connected to the first sun gear SG1 of the first planetary row of the transmission TM to always be in transmission connection, so that the rotor shaft S1 and the first sun gear SG1 can transmit torque in both directions. When the motor EM is supplied with electric energy by a battery, the motor EM can output torque to the outside as an electric motor; when the motor EM obtains torque from the outside, the motor EM can charge the battery as a generator EM.

[0033] In this embodiment, if Figure 1 As shown, the transmission TM can realize a torque transmission path with a large transmission ratio in a relatively compact structure. Specifically, the transmission TM includes a first planetary gear, a second planetary gear and an output shaft S2 assembled together.

[0034] The first planetary row includes a first sun gear SG1, a plurality of first planetary gears PG1, a first planetary gear carrier PC1 and a first ring gear RG1 assembled together. The first sun gear SG1 is directly connected to the rotor shaft S1 of the motor EM to be always in transmission connection. The plurality of first planetary gears PG1 are located radially outside the first sun gear SG1 and are evenly distributed along the circumference. Each first planetary gear PG1 is always in meshing with the first sun gear SG1, so that as the first sun gear SG1 rotates, each first planetary gear PG1 can rotate around its own central axis and revolve around the first sun gear SG1. The plurality of first planetary gears PG1 are installed on the first planetary gear carrier PC1, and the first planetary gear carrier PC1 is directly connected to the second sun gear SG2 of the second planetary row to be always in transmission connection. The revolution of the plurality of first planetary gears PG1 can drive the first planetary gear carrier PC1 to rotate, and the rotation of the first planetary gear carrier PC1 can drive the plurality of first planetary gears PG1 to revolve. The first ring gear RG1 is located radially outside the plurality of first planetary gears PG1, and a track for the plurality of first planetary gears PG1 to revolve is formed between the first ring gear RG1 and the first sun gear SG1, and the first ring gear RG1 is always in meshing engagement with the plurality of first planetary gears PG1. In addition, the first ring gear RG1 can be fixed to the housing H so that the first ring gear RG1 cannot rotate relative to the housing H.

[0035] The second planetary gear row includes a second sun gear SG2, a plurality of second planetary gears PG2, a second planetary gear carrier PC2 and a second ring gear RG2 assembled together. As described above, the second sun gear SG2 is always connected to the first planetary gear carrier PC1 in transmission. The plurality of second planetary gears PG2 are located radially outside the second sun gear SG2 and are evenly distributed along the circumference. Each second planetary gear PG2 is always meshed with the second sun gear SG2, so that as the second sun gear SG2 rotates, each second planetary gear PG2 can rotate around its own central axis and revolve around the second sun gear SG2. The plurality of second planetary gears PG2 are installed on the second planetary gear carrier PC2. The revolution of the plurality of second planetary gears PG2 can drive the second planetary gear carrier PC2 to rotate, and the rotation of the second planetary gear carrier PC2 can drive the plurality of second planetary gears PG2 to revolve. The second planetary gear carrier PC2 is directly connected to the output shaft S2 to be always connected in transmission. The second ring gear RG2 is located radially outside the plurality of second planetary gears PG2, and a track for the plurality of second planetary gears PG2 to revolve is formed between the second ring gear RG2 and the second sun gear SG2, and the second ring gear RG2 is always in meshing engagement with the plurality of second planetary gears PG2. In addition, the second ring gear RG2 can be fixed to the housing H so that the second ring gear RG2 cannot rotate relative to the housing H.

[0036] By adopting the above-mentioned transmission TM, the transmission path of the torque from the motor EM is as follows: motor EM (rotor shaft S1) → first sun gear SG1 → first planetary gear PG1 → first planetary gear carrier PC1 → second sun gear SG2 → second planetary gear PG2 → second planetary gear carrier PC2 → output shaft S2. Thus, the torque of the motor EM can be output to the outside via the transmission TM.

[0037] In order to reduce the axial size of the electric bridge drive system, in this embodiment, as shown in FIG. Figure 1 As shown, the first planetary row is located radially inside the protruding portion of the winding WI of the stator ST, and a portion of the structure of the first planetary row overlaps with the protruding portion in the axial direction A. That is to say, when observed from the radial direction R perpendicular to the axial direction A, the protruding portion of the winding WI and a portion of the first planetary row are shielded from each other. Furthermore, the second planetary row is completely offset from the motor EM in the axial direction A. In this way, the second planetary row can have a larger radial dimension, which is conducive to building a transmission TM that can achieve a larger transmission ratio and transmit a larger torque.

[0038] In this embodiment, if Figure 1 As shown, most structures of both the motor EM and the transmission TM are accommodated and installed in the internal space of the housing H. The housings H of the two electric bridge drive units EU can be assembled together through connectors. The housing H can be provided with a detachable body and end cover, which is conducive to the installation and maintenance of the motor EM and the transmission TM.

[0039] It can be understood that the output shaft S2 may not be a part of the electric bridge drive system of the present application, and it may be detachably connected to the second planetary wheel carrier PC2.

[0040] The following description includes two examples of vehicles using the electric axle drive system described above.

[0041] In one example, the vehicle according to the present application may include an electric bridge drive system having the above structure, wherein the output shafts S2 of the two electric bridge drive units EU of the electric bridge drive system are respectively connected to the two front wheels of the vehicle. In this way, the motors EM of the two electric bridge drive units EU can independently drive the two front wheels to rotate.

[0042] In another example, the vehicle according to the present application may include an electric bridge drive system having the above structure, wherein the output shafts S2 of the two electric bridge drive units EU of the electric bridge drive system are respectively connected to the two rear wheels of the vehicle. In this way, the motors EM of the two electric bridge drive units EU can independently drive the two rear wheels to rotate.

[0043] In the above-mentioned vehicles, since an electric bridge drive system according to the first embodiment of the present application is adopted, not only the transmission ratio is improved with a compact structure, thereby reducing the torque requirement for the output of the motor EM, but also the axial size of the entire electric bridge drive system and the space occupied are reduced.

[0044] The electric bridge driving system according to the second embodiment of the present application will be described below in conjunction with the accompanying drawings.

[0045] (Electric bridge drive system according to the second embodiment of the present application)

[0046] The structure of the electric bridge drive system according to the second embodiment of the present application is substantially the same as the structure of the electric bridge drive system according to the first embodiment of the present application, and the differences between the two are mainly described below.

[0047] In this embodiment, if Figure 2 As shown, the rotor shaft S1 is formed into a hollow structure. In the case where the first planetary row does not need to transmit excessive torque, a first planetary row with a smaller radial size can be constructed. Except for the first planetary wheel carrier PC1, the first planetary row is located in the rotor shaft S1 as a whole, a part of the first planetary wheel carrier PC1 is located in the rotor shaft S1 and another part extends from the rotor shaft S1. The second planetary row is located radially inside the extended part of the winding WI of the stator ST, and a part of the second planetary row overlaps with the extended part. In this way, compared with the first embodiment, the axial size and the space occupied by the entire electric bridge drive system can be further reduced.

[0048] It can be understood that the motor EM may include a rotor shaft and a rotor support connecting the rotor shaft and the rotor stack. In this case, the rotor shaft does not have to be a hollow shaft, and the first planetary row as a whole may be located radially inward of the outer periphery (the part extending axially) of the rotor RO or the rotor support.

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

[0050] i. In order to reduce the axial size and occupied space of the entire electric bridge drive system, it is not necessary to adopt the specific solution described in the above embodiments. It is only necessary that at least a portion of the transmission TM overlaps with the motor EM in the axial direction A of the electric bridge drive system.

[0051] ii. In the above embodiments, if Figure 1 and Figure 2 As shown, the electric bridge drive unit EU may further include a plurality of bearings mounted on the housing H. These bearings are used not only to support the first planetary carrier PC1 and the second planetary carrier PC2 so that the first planetary carrier PC1 and the second planetary carrier PC2 can stably rotate relative to the housing H, but also to support the rotor shaft S1 so that the rotor shaft S1 can stably rotate relative to the housing H.

[0052] iii. In the above embodiments, in addition to outputting torque for driving to the transmission TM, the motor EM can also receive torque from the transmission TM to charge the battery.

[0053] iv. In the electric bridge drive system described in the above specific embodiment, the rotor shaft S1 of each motor EM is directly used as the input shaft of the transmission TM, but the present application is not limited thereto. An input shaft of the transmission TM independent of the rotor shaft S1 can be provided, and then the rotor shaft S1 and the input shaft of the transmission TM are rigidly connected together through, for example, a coupling.

[0054] v. The electric bridge drive system according to the present application can be applied to pure electric vehicles or hybrid vehicles. If necessary, a vehicle can include more than two electric bridge drive systems according to the present application.

Claims

1. A bridge drive system, characterized in that: The electric bridge drive system comprises two coaxially arranged electric bridge drive units (EU), each electric bridge drive unit (EU) comprises an electric motor (EM) and a transmission (TM), the transmission (TM) is coaxially arranged with the electric motor (EM), at least a portion of the transmission (TM) overlaps with the electric motor (EM) in an axial direction (A) of the electric bridge drive system, The motor (EM) includes a rotor (RO) and a stator (ST), and the transmission (TM) includes a first planetary row and a second planetary row, the first planetary row includes a first sun gear (SG1) assembled together, a plurality of first planetary gears (PG1), a first planetary gear carrier (PC1) and a first ring gear (RG1), the first sun gear (SG1) is connected to the rotor (RO) to achieve transmission connection, the first ring gear (RG1) is fixed relative to the stator (ST), the second planetary row includes a second sun gear (SG2) assembled together, a plurality of second planetary gears (PG2), a second planetary gear carrier (PC2) and a second ring gear (RG2), the second sun gear (SG2) is connected to the first planetary gear carrier (PC1) to achieve transmission connection, and the second ring gear (RG2) is fixed relative to the stator (ST), so that the torque from the rotor (RO) can be output to the outside via the second planetary gear carrier (PC2).

2. The electric bridge drive system according to claim 1, characterized in that: For one of the two electric bridge drive units (EU), the transmission (TM) is located at one axial end of the electric motor (EM); and For the other one of the two electric axle drive units (EU), the transmission (TM) is located at the other axial end of the electric machine (EM).

3. The electric bridge drive system according to claim 1 or 2, characterized in that: The stator (ST) includes an iron core (IC) and a winding (WI), the winding (WI) includes a protruding portion extending from the iron core (IC), the first planetary row is located radially inside the protruding portion, and at least a portion of the first planetary row overlaps with the protruding portion in the axial direction (A).

4. The electric bridge drive system according to claim 3, characterized in that: The second planetary gear is offset from the electric motor (EM) in the axial direction (A).

5. The electric bridge drive system according to claim 1 or 2, characterized in that: The first planet row is located in the rotor (RO) and the first planet wheel carrier (PC1) extends from the rotor (RO) along the axial direction (A).

6. The electric bridge drive system according to claim 5, characterized in that: The stator (ST) includes an iron core (IC) and a winding (WI), the winding (WI) includes a protruding portion extending from the iron core (IC), the second planetary row is located radially inside the protruding portion, and at least a portion of the second planetary row overlaps with the protruding portion in the axial direction (A).

7. The electric bridge drive system according to claim 1 or 2, characterized in that: The electric bridge drive unit (EU) comprises a housing (H), and the ring gear is fixed to the housing (H).

8. The electric bridge drive system according to claim 7, characterized in that: The electric bridge drive unit (EU) includes a plurality of bearings mounted on the housing (H), and the plurality of bearings are used to support the first planetary wheel carrier (PC1) and the second planetary wheel carrier (PC2), so that the first planetary wheel carrier (PC1) and the second planetary wheel carrier (PC2) can rotate relative to the housing (H).

9. A vehicle, characterized in that: The electric bridge drive system comprises the electric bridge drive system according to any one of claims 1 to 8.

10. The vehicle according to claim 9, characterized in that The electric bridge drive system further comprises a first wheel and a second wheel, wherein the first wheel and the second wheel are respectively connected to two electric bridge drive units (EU) of the electric bridge drive system through transmission. The first wheel and the second wheel are both front wheels or the first wheel and the second wheel are both rear wheels.

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