Two-speed electric axle drive system and vehicle

Abstract

This invention provides a two-speed electric axle drive system for vehicles and a vehicle employing the same system. The transmission of this two-speed electric axle drive system includes a dual clutch and a planetary gear mechanism. The dual clutch allows torque from the electric motor to be selectively transmitted to the differential via either the sun gear or the planetary gear carrier of the planetary gear mechanism. Therefore, the two-speed electric axle drive system according to this invention not only has a relatively simple structure but also achieves seamless power transitions during gear shifts.

Description

Technical Field

[0001] This invention relates to the field of vehicles, and more particularly to a two-speed electric axle drive system for vehicles and a vehicle including the two-speed electric axle drive system. Background Technology

[0002] Currently, electric axle drive systems can be used in both pure electric and hybrid vehicles for vehicle propulsion.

[0003] Figure 1a This is a schematic diagram showing the topology of a two-speed electric bridge drive system, where the motor, as the drive source, is omitted. Figure 1a As shown, the two-speed electric bridge drive system includes a motor (not shown), a planetary gear mechanism, a synchronous meshing mechanism SN, an intermediate transmission mechanism, a differential DM, and two half-shafts.

[0004] Specifically, the planetary gear mechanism includes a sun gear SU, a sun gear shaft S, multiple planet gears PG, a ring gear R, and a planet carrier P. The sun gear SU is fixed to the sun gear shaft S, which receives torque from the motor. The multiple planet gears PG are located radially outside the sun gear SU and radially inside the ring gear R, and are always meshed with the sun gear SU and the ring gear R. The multiple planet gears PG are mounted on the planet carrier P, allowing the planet carrier P to rotate as the multiple planet gears PG revolve around the sun gear SU. The ring gear R is fixed to the transmission housing. In this way, the planetary gear mechanism can initially change the transmission ratio in the torque transmission path of the transmission.

[0005] The synchronizing mechanism SN can employ existing synchronizing mechanisms. When the synchronizing mechanism SN performs corresponding actions to be in different engaged positions, it can select two torque transmission paths to transmit torque to the vehicle's wheels: one from the sun gear shaft S and the other from the planetary gear carrier P. When the synchronizing mechanism SN is in the unengaged neutral position, the entire electric axle drive system does not transmit torque to the vehicle's wheels.

[0006] The intermediate transmission mechanism includes a first intermediate gear G11, a second intermediate gear G12, a third intermediate gear G13, and an intermediate shaft MS. The first intermediate gear G11 is connected to the synchronizing mechanism SN to receive torque from the planetary gear mechanism, and the first intermediate gear G11 and the second intermediate gear G12 are always meshed. The second intermediate gear G12 and the third intermediate gear G13 are both fixed to the intermediate shaft MS. The third intermediate gear G13 is always meshed with the differential input gear G14. Thus, the intermediate shaft MS and the fixed second and third intermediate gears G12 and G13 can further change the transmission ratio of the torque transmission path after the planetary gear mechanism.

[0007] Two half-shafts extend from the differential DM to both sides. The housing of the differential DM is fixed to the differential input gear G14, thereby receiving torque via the differential input gear G14 and transmitting it to the two half-shafts.

[0008] Although Figure 1a The electric axle drive system shown can achieve two-speed drive with different transmission ratios through a planetary gear mechanism and a synchronizing mechanism SN, but it will cause a power interruption during the shifting process, thus affecting the driving performance of the vehicle.

[0009] Figure 1b This is a schematic diagram illustrating another two-speed electric bridge drive system topology. (See diagram for example.) Figure 1b As shown, the two-speed electric axle drive system includes a motor EM, a transmission, a differential DM, and two half-shafts.

[0010] Specifically, the motor EM has an output shaft and a motor output gear G15 fixed to the output shaft.

[0011] Furthermore, the transmission includes a hollow sun gear shaft S, a transmission input gear G16 fixed to the sun gear shaft S, two planetary gear mechanisms, and two clutches K1 and K2.

[0012] The sun gear shaft S is parallel to and offset relative to the output shaft of the motor EM. The input gear G15 of the transmission and the output gear G16 of the motor are always in mesh, so that the transmission can receive torque from the motor EM.

[0013] The first planetary gear mechanism includes a first sun gear SU1 meshing with each other, a plurality of first planet gears PG1, a first ring gear R1, and a planet carrier P mounted on the plurality of first planet gears PG1. The first sun gear SU1 is fixed to the sun gear shaft S. The planet carrier P is fixed to the differential housing of the differential DM. The first ring gear R1 is connected to the transmission housing via a first clutch K1, so that the engagement of the first clutch K1 can fix the first ring gear R1 relative to the transmission housing. Similarly, the second planetary gear mechanism includes a second sun gear SU2 meshing with each other, a plurality of second planet gears PG2, a second ring gear R2, and a planet carrier P mounted on the plurality of second planet gears PG2. The second sun gear SU2 is fixed to the sun gear shaft S. The second planetary gear mechanism shares a planet carrier P with the first planetary gear mechanism. The second ring gear R2 is connected to the transmission housing via a second clutch K2, so that the engagement of the second clutch K2 can fix the second ring gear R2 relative to the transmission housing.

[0014] Although Figure 1bThe electric bridge drive system shown can achieve two-speed drive with different transmission ratios via two planetary gear mechanisms and two clutches K1 and K2, but its structure is too complicated for an electric bridge drive system that can achieve two-speed drive. Summary of the Invention

[0015] The present invention was made in view of the deficiencies of the prior art. One object of the present invention is to provide a novel two-speed electric axle drive system, which has a simple structure and can avoid power interruption during gear shifting. Another object of the present invention is to provide a vehicle including the above-described two-speed electric axle drive system.

[0016] To achieve the above objectives, the present invention adopts the following technical solution.

[0017] This invention provides a two-speed electric bridge drive system, the two-speed electric bridge drive system comprising:

[0018] An electric motor, the electric motor having an output shaft; and

[0019] The transmission includes a dual clutch, a first input shaft, a second input shaft, and a planetary gear mechanism.

[0020] The motor output shaft can be selectively connected to the first input shaft and the second input shaft via the dual clutch. The planetary gear mechanism includes a sun gear, multiple planet gears, a planet carrier, and a ring gear. The sun gear is fixed to the first input shaft and is always meshed with the multiple planet gears. The multiple planet gears are always meshed with the ring gear and are mounted on the planet carrier. The planet carrier is fixed to the second input shaft and is used to transmit torque to the outside of the planetary gear mechanism. The ring gear is fixed to the housing of the transmission.

[0021] Preferably, the first input shaft, the second input shaft, and the planetary gear mechanism are all configured coaxially with the motor output shaft.

[0022] More preferably, the first input shaft is a solid shaft and the second input shaft is a hollow shaft. The first input shaft passes through the second input shaft and the planetary gear carrier, and bearings for supporting the first input shaft are provided between the first input shaft and the second input shaft and between the first input shaft and the planetary gear carrier.

[0023] More preferably, the dual clutch includes a first clutch unit and a second clutch unit.

[0024] When the first clutch unit is engaged, the motor output shaft is connected to the first input shaft; when the first clutch unit is disengaged, the motor output shaft is disconnected from the first input shaft, and

[0025] When the second clutch unit is engaged, the motor output shaft and the second input shaft are connected in a transmission manner; when the second clutch unit is disengaged, the motor output shaft and the second input shaft are disconnected from the transmission manner.

[0026] More preferably, the two-speed electric axle drive system further includes a differential and two half-shafts extending from the differential, wherein the planetary gear carrier output gear of the planetary gear carrier is connected to the differential input gear of the differential.

[0027] More preferably, the planetary gear carrier output gear and the differential input gear are always in a meshing state, so that the planetary gear carrier output gear and the differential input gear achieve direct drive connection.

[0028] More preferably, the transmission further includes at least one intermediate shaft and a plurality of intermediate gears fixed to the intermediate shaft, through which the planetary gear carrier output gear and the differential input gear are indirectly connected.

[0029] More preferably, the differential is a bevel gear differential.

[0030] More preferably, the housing of the two-speed electric bridge drive system includes a first housing portion, a second housing portion, and a third housing portion that are detachably connected to each other in the axial direction of the motor output shaft. A portion of the second housing portion is used to form the housing of the motor, and another portion of the second housing portion is used to form the housing of the transmission.

[0031] The present invention also provides a vehicle comprising the two-speed electric axle drive system described in any one of the above technical solutions.

[0032] By adopting the above technical solution, the present invention provides a novel two-speed electric axle drive system and a vehicle including the two-speed electric axle drive system. The transmission of the two-speed electric axle drive system includes a dual clutch and a planetary gear mechanism. The dual clutch allows torque from the electric motor to be selectively transmitted to the differential via the sun gear or planet carrier of the planetary gear mechanism. Therefore, the two-speed electric axle drive system according to the present invention not only has a relatively simple structure but also achieves no power interruption during gear shifting. Attached Figure Description

[0033] Figure 1a This is a schematic diagram showing the topology of a two-speed electric bridge drive system; Figure 1b This is a schematic diagram showing another two-speed electric bridge drive system topology.

[0034] Figure 2 This is a schematic diagram showing the topology of a two-speed electric bridge drive system according to a first embodiment of the present invention.

[0035] Figure 3 This is a schematic diagram showing the topology of a two-speed electric bridge drive system according to a second embodiment of the present invention.

[0036] Explanation of reference numerals in the attached figures

[0037] EM motor SN synchronous meshing mechanism DM differential

[0038] SU Sun Gear S Sun Gear Shaft PG Planet Gears P Planet Carrier R Ring Gear SU1 First Sun Gear SU2 Second Sun Gear PG1 First Planet Gear PG2 Second Planet Gear R1 First Ring Gear R2 Second Ring Gear

[0039] K0 Dual Clutch, K11 First Clutch Unit, K12 Second Clutch Unit, K1 First Clutch, K2 Second Clutch

[0040] S0 Motor output shaft, S1 First input shaft, S2 Second input shaft, MS Intermediate shaft

[0041] Gears G1, G2, G3, G4, G11, G12, G13, G14, G15, G16

[0042] H11 First shell section, H12 Second shell section, H13 Third shell section, H14 Partition. Detailed Implementation

[0043] Exemplary embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood that these specific descriptions are for teaching those skilled in the art how to implement the present invention, and are not intended to exhaustively describe all possible ways of the invention, nor to limit the scope of the invention.

[0044] In this invention, "transmission connection" refers to a connection between two components that enables the transmission of driving force / torque. Unless otherwise specified, this can mean that the two components are directly connected (direct transmission connection) or connected via a transmission mechanism such as a gear mechanism (indirect transmission connection) to transmit driving force / torque between the two components. Furthermore, when it is stated that a gear is "fixed to" a shaft, it means that the gear can rotate with the shaft, not that the gear is fixed relative to the shaft in the axial direction. Additionally, in this invention, unless otherwise specified, "axial" refers to the axial direction of the motor output shaft and the transmission input shaft, and "one side of the axial direction" refers to... Figure 2 and Figure 3The right side of the axis, "the other side of the axis" refers to Figure 2 and Figure 3 On the left side of the middle.

[0045] The structure of the two-speed electric bridge drive system according to the first embodiment of the present invention will be described below with reference to the accompanying drawings.

[0046] (Structure of the two-speed electric bridge drive system according to the first embodiment of the present invention)

[0047] Figure 2 This is a schematic diagram illustrating the topology of a two-speed electric bridge drive system according to a first embodiment of the present invention. Figure 2 As shown, the two-speed electric axle drive system according to the first embodiment of the present invention includes an integrated motor EM, a transmission, a differential DM, and two half shafts, wherein the motor EM, the transmission, and the differential DM are all mounted in the housing of the two-speed electric axle drive system assembled from multiple housing parts H11, H12, and H13.

[0048] Specifically, in this embodiment, the motor EM has a motor output shaft S0 that extends axially to one side to the transmission so as to transmit the torque of the motor EM to the transmission.

[0049] Furthermore, in this embodiment, the transmission is located on one axial side of the motor EM and is a dual-clutch transmission, which includes a dual clutch K0 (with two clutch units K11 and K12 that can work independently of each other), a solid first input shaft S1, a hollow second input shaft S2, and a planetary gear mechanism.

[0050] The first input shaft S1, the second input shaft S2, and the planetary gear mechanism are all coaxially arranged with the motor output shaft S0. The first input shaft S1 passes through the second input shaft S2 and is located radially inside the second input shaft S2, and the first input shaft S1 can rotate independently of the second input shaft S2. Moreover, the first input shaft S1 and the second input shaft S2 are connected to the motor output shaft S0 via a dual clutch K0. Thus, when the first clutch unit K11 is engaged, the first input shaft S1 is connected to the motor output shaft S0; when the first clutch unit K11 is disengaged, the first input shaft S1 is disconnected from the motor output shaft S0. When the second clutch unit K12 is engaged, the second input shaft S2 is connected to the motor output shaft S0; when the second clutch unit K12 is disengaged, the second input shaft S2 is disconnected from the motor output shaft S0.

[0051] The planetary gear mechanism is located on one axial side of the dual clutch K0 and includes a sun gear SU, multiple planet gears PG, a ring gear R, and a planet carrier P. The sun gear SU is fixed to the first input shaft S1. The multiple planet gears PG are located radially outside the sun gear SU and radially inside the ring gear R, and the multiple planet gears PG are always meshed with the sun gear SU and the ring gear R. The multiple planet gears PG are mounted on the planet carrier P so that the planet carrier P can rotate with the multiple planet gears PG revolving around the sun gear SU. The first input shaft S1 is located radially inside the planet carrier P and extends through the planet carrier P. The ring gear R is fixed to the transmission housing (second housing portion H12). In addition, the planetary gear mechanism also includes a planet carrier output gear G1 fixed to the planet carrier P, which is always meshed with the differential input gear G2 described below, so that the two are directly connected for transmission.

[0052] The dual-clutch K0 can be a wet clutch and includes a first clutch unit K11 and a second clutch unit K12, which can operate independently of each other as described above. When the dual-clutch K0 is working normally, only one of the first clutch unit K11 and the second clutch unit K12 is engaged; when the dual-clutch K0 shifts gears, the two clutch units K11 and K12 can achieve uninterrupted torque transfer within the transmission, that is, uninterrupted power within the transmission, thereby avoiding the phenomenon of power interruption during gear shifting.

[0053] Furthermore, in this embodiment, the differential DM is a bevel gear differential and is also integrated into the housing of the two-speed electric axle drive system. The differential input gear G2 is fixed to the differential housing and, as described above, is always meshed with the planetary gear carrier output gear G1. Two half-shafts extend axially from the differential DM and are capable of transmitting torque to the vehicle's wheels.

[0054] Thus, in this embodiment, when the dual clutch K0 is in normal operating condition,

[0055] When the first clutch unit K11 is engaged, the torque transmission path from the motor EM is as follows: motor EM → motor output shaft S0 → first clutch unit K11 → first input shaft S1 → sun gear SU → planet gear PG → planet carrier P → planet carrier output gear G1 → differential input gear G2 → differential DM.

[0056] When the second clutch unit K12 is engaged, the torque transmission path from the motor EM is as follows: motor EM → motor output shaft S0 → second clutch unit K12 → second input shaft S2 → planetary gear carrier P → planetary gear carrier output gear G1 → differential input gear G2 → differential DM.

[0057] Furthermore, the housing of the two-speed electric axle drive system according to the first embodiment of the present invention includes a first housing portion H11, a second housing portion H12, a third housing portion (end cover) H13, and a partition H14 installed inside the second housing portion H12, which are detachably fixed together with each other. The second housing portion H12 is a common part for the housing of the motor and the housing of the transmission. The motor EM is housed in the space surrounded by the second housing portion H12 and the third housing portion H13. The transmission and the differential DM are both housed in the space surrounded by the second housing portion H12 and the first housing portion H11. The partition H14 separates the dual clutch K0 from the planetary gear mechanism and the differential DM. In this way, the structure of the housing of the entire two-speed electric axle drive system is simplified.

[0058] The structure of the two-speed electric bridge drive system according to the first embodiment of the present invention has been described above. The structure of the two-speed electric bridge drive system according to the second embodiment of the present invention will be described below with reference to the accompanying drawings.

[0059] (Structure of the two-speed electric bridge drive system according to the second embodiment of the present invention)

[0060] The basic structure of the two-speed electric bridge drive system according to the second embodiment of the present invention is largely the same as that of the two-speed electric bridge drive system according to the first embodiment of the present invention. The differences between the two will be described below.

[0061] In this embodiment, such as Figure 3 As shown, the transmission of the two-speed electric axle drive system also includes an intermediate shaft MS and a first intermediate gear G3 and a second intermediate gear G4 fixed to the intermediate shaft MS. The first intermediate gear G3 is always meshed with the planetary gear carrier output gear G1, and the second intermediate gear G4 is always meshed with the differential input gear G2. In this way, the transmission ratio in the torque transmission path of the transmission can be further changed through the intermediate shaft MS and the first and second intermediate gears G3 and G4.

[0062] Thus, in this embodiment, when the dual clutch K0 is in normal operating condition,

[0063] When the first clutch unit K11 is engaged, the torque transmission path from the motor EM is as follows: motor EM → motor output shaft S0 → first clutch unit K11 → first input shaft S1 → sun gear SU → planet gear PG → planet carrier P → planet carrier output gear G1 → first intermediate gear G3 → intermediate shaft MS → second intermediate gear G4 → differential input gear G2 → differential DM.

[0064] When the second clutch unit K12 is engaged, the torque transmission path from the motor EM is as follows: motor EM → motor output shaft S0 → second clutch unit K12 → second input shaft S2 → planetary gear carrier P → planetary gear carrier output gear G1 → first intermediate gear G3 → intermediate shaft MS → second intermediate gear G4 → differential input gear G2 → differential DM.

[0065] Furthermore, the present invention also provides a vehicle comprising a two-speed electric axle drive system with the above structure, which has the advantages that can be achieved by the two-speed electric axle drive system according to the present invention, and the two-speed electric axle drive system according to the present invention has a compact structure, which is beneficial to the structural layout of the vehicle.

[0066] Although the technical solution of the present invention has been described in detail in the above specific embodiments, the following should also be explained.

[0067] i. Although not explicitly stated in the above specific embodiments, it should be understood that in the above embodiments, in addition to outputting torque to the transmission for driving, the motor EM can also receive torque from the transmission (e.g., regenerative braking) for charging the battery.

[0068] ii. Although not explicitly stated in the above specific embodiments, it should be understood that the motor output shaft S0 of the motor, as well as the first input shaft S1, the second input shaft S2, the intermediate shaft MS, and the planetary gear carrier P of the transmission, are all supported by corresponding bearings. For example, since the first input shaft S1 passes through both the second input shaft S2 and the planetary gear carrier P, bearings are provided between the first input shaft S1 and the second input shaft S2, and between the first input shaft S1 and the planetary gear carrier P, to support the first input shaft S1.

[0069] iii. By adopting the above technical solution, the two-speed electric bridge drive system according to the present invention has a relatively simple structure and small size. Moreover, the performance of the two-speed electric bridge drive system according to the present invention is significantly better than that of the single-speed electric bridge drive system, and it can provide a large transmission ratio with a compact structure.

Claims

1. A two-speed electric bridge drive system, characterized in that, The two-speed electric bridge drive system includes: An electric motor (EM) having an output shaft (S0); and The transmission includes a dual clutch (K0), a first input shaft (S1), a second input shaft (S2), and a planetary gear mechanism. The motor output shaft (S0) can be selectively connected to the first input shaft (S1) and the second input shaft (S2) via the dual clutch (K0). The planetary gear mechanism includes a sun gear (SU), multiple planet gears (PG), a planet carrier (P), and a ring gear (R). The sun gear (SU) is fixed to the first input shaft (S1) and is always meshed with the multiple planet gears (PG). The multiple planet gears (PG) are always meshed with the ring gear (R) and are mounted on the planet carrier (P). The planet carrier (P) is fixed to the second input shaft (S2) and is used to transmit torque to the outside of the planetary gear mechanism. The ring gear (R) is fixed to the housing of the transmission. The housing contains a partition that separates the dual clutch from the planetary gear mechanism.

2. The two-speed electric bridge drive system according to claim 1, characterized in that, The first input shaft (S1), the second input shaft (S2), and the planetary gear mechanism are all configured coaxially with the motor output shaft (S0).

3. The two-speed electric bridge drive system according to claim 2, characterized in that, The first input shaft (S1) is a solid shaft, and the second input shaft (S2) is a hollow shaft. The first input shaft (S1) passes through the second input shaft (S2) and the planetary gear carrier (P). Bearings for supporting the first input shaft (S1) are provided between the first input shaft (S1) and the second input shaft (S2) and between the first input shaft (S1) and the planetary gear carrier (P).

4. The two-speed electric bridge drive system according to any one of claims 1 to 3, characterized in that, The dual clutch (K0) includes a first clutch unit (K11) and a second clutch unit (K12). When the first clutch unit (K11) is engaged, the motor output shaft (S0) and the first input shaft (S1) are connected in a transmission manner; when the first clutch unit (K11) is disengaged, the motor output shaft (S0) and the first input shaft (S1) are disconnected in a transmission manner, and When the second clutch unit (K12) is engaged, the motor output shaft (S0) and the second input shaft (S2) are connected in a transmission manner; when the second clutch unit (K12) is disengaged, the motor output shaft (S0) and the second input shaft (S2) are disconnected in a transmission manner.

5. The two-speed electric bridge drive system according to any one of claims 1 to 3, characterized in that, The two-speed electric axle drive system also includes a differential (DM) and two half-shafts extending from the differential (DM). The planetary gear carrier output gear (G1) of the planetary gear carrier (P) is drive-connected to the differential input gear (G2) of the differential (DM).

6. The two-speed electric bridge drive system according to claim 5, characterized in that, The planetary gear carrier output gear (G1) and the differential input gear (G2) are always in a meshed state, so that the planetary gear carrier output gear (G1) and the differential input gear (G2) achieve direct drive connection.

7. The two-speed electric bridge drive system according to claim 5, characterized in that, The transmission also includes at least one intermediate shaft (MS) and a plurality of intermediate gears (G3, G4) fixed to the intermediate shaft (MS), through which the planetary gear carrier output gear (G1) and the differential input gear (G2) are indirectly connected.

8. The two-speed electric bridge drive system according to claim 5, characterized in that, The differential (DM) is a bevel gear differential.

9. The two-speed electric bridge drive system according to any one of claims 1 to 3, characterized in that, The housing of the two-speed electric bridge drive system includes a first housing portion (H11), a second housing portion (H12), and a third housing portion (H13) that are detachably connected to each other in the axial direction of the motor output shaft (S0). A portion of the second housing portion (H12) is used to form the housing of the motor (EM), and another portion of the second housing portion (H12) is used to form the housing of the transmission.

10. A vehicle, characterized in that, The vehicle includes a two-speed electric axle drive system as described in any one of claims 1 to 9.

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