Transmission mechanism and double-motor electric drive axle assembly

Abstract

The invention relates to a transmission mechanism and a double-motor electric drive axle assembly. The transmission mechanism comprises a first input shaft and a second input shaft, a sun gear of the first planetary reducer is connected with a first input shaft and a second input shaft, a planet carrier serves as an output end, and the second input shaft is connected with the sun gear through a first one-way transmission part and connected with the planet carrier through a one-way transmission structure. The second input shaft rotates in the first rotating direction, transmits power to the sun gear through the first one-way transmission piece and disconnects power transmission with the one-way transmission structure, and the second input shaft rotates reversely, transmits power to the planet carrier through the one-way transmission structure and disconnects power transmission with the sun gear. When the second input shaft rotates in the first rotation direction or rotates in the reverse direction, the rotation directions of the planet carriers are the same. The power requirements of high-speed driving and climbing working conditions can be met, the power of a single motor is low, the highest rotating speed of the motor is low, the falling point of an efficient area tends to be consistent with the working condition point of the whole vehicle, and the utilization rate of the efficient area is high.

Description

Technical Field

[0001] The present invention relates to the technical field of electric drive systems, and in particular to a transmission mechanism and a dual-motor electric drive axle assembly. Background Art

[0002] The electric drive axle is the mainstream development trend of the current new energy vehicle power system, which can meet the needs of new energy vehicle power system integration, high efficiency and lightweight.

[0003] The structural difficulty of the electric drive axle lies in arranging the reduction mechanism in the limited space of the bridge housing so that the whole vehicle can meet both the conventional driving needs and the needs of climbing and high-speed driving.

[0004] Currently, electric drive axles mostly adopt the structure of a single motor plus a two-speed reducer. In order to meet the needs of climbing and high-speed driving, the size and power of the single motor need to be relatively large, resulting in inconsistency between the motor's high-efficiency zone and the vehicle's operating conditions, and low utilization of the motor's high-efficiency zone. Summary of the invention

[0005] Based on the above description, the present invention provides a transmission mechanism and a dual-motor electric drive axle assembly to solve the problem that the electric drive axle in the related art adopts the structure of a single motor plus a two-speed reducer, which requires the size and power of the single motor to be relatively large, resulting in inconsistency between the motor's high-efficiency zone and the vehicle's operating conditions, and low utilization of the motor's high-efficiency zone.

[0006] The technical solution of the present invention to solve the above technical problems is as follows: In the first aspect, the present application provides a transmission mechanism, and the technical solution adopted is as follows: A transmission mechanism, comprising: The first input shaft and the second input shaft are respectively used to connect to different power sources; A first planetary reducer, whose sun gear serves as a power input end and is coaxially connected to the first input shaft and the second input shaft, and a planet carrier serves as an output end for outputting power. The second input shaft is connected to the sun gear of the first planetary reducer through a first one-way transmission member, and is connected to the planet carrier of the first planetary reducer through a one-way transmission structure. When the second input shaft rotates along a first rotation direction, power is transmitted to the sun gear of the first planetary reducer through the first one-way transmission member, and the power transmission with the one-way transmission structure is disconnected. When the second input shaft rotates in the opposite direction, power is transmitted to the planet carrier of the first planetary reducer through the one-way transmission structure, and the power transmission with the sun gear of the first planetary reducer is disconnected. When the second input shaft rotates in the first rotation direction or rotates in the opposite direction, the direction in which the planet carrier of the first planetary reducer is driven to rotate is the same.

[0007] Preferably, it also includes a first shifting mechanism, which is used to connect the bridge housing and the ring gear of the first planetary reducer, and the first shifting mechanism is used to limit the rotation of the ring gear of the first planetary reducer and can release the restriction, and when the second input shaft rotates in a direction opposite to the first rotation direction, power is transmitted to the ring gear of the first planetary reducer through the one-way transmission structure.

[0008] Preferably, the one-way transmission structure includes a second planetary reducer and a second one-way transmission member, the sun gear of the second planetary reducer is coaxial with the sun gear of the first planetary reducer, the planetary carrier of the second planetary reducer is used to be fixed to the bridge housing, the ring gear of the second planetary reducer is fixed to the ring gear of the first planetary reducer, the second input shaft is connected to the sun gear of the second planetary reducer through the second one-way transmission member, and when the second input shaft rotates in a direction opposite to the first rotation direction, power is transmitted to the sun gear of the second planetary reducer through the second one-way transmission member.

[0009] Preferably, the first shift mechanism includes a first sliding engagement sleeve, which is used to be connected to the bridge housing and is restricted from rotating relative to the bridge housing, and the first sliding engagement sleeve can slide axially to engage with or disengage from the ring gear of the first planetary reducer.

[0010] Preferably, the second input shaft includes a first segment and a second segment, the first segment is connected to the sun gear of the first planetary reducer through the first one-way transmission member, the second segment is connected to the planetary carrier of the first planetary reducer through the one-way transmission structure, the first segment can be selectively connected or disconnected with the second segment through a second shifting mechanism, and is suitable for disconnecting the first segment and the second segment through the second shifting mechanism when the sun gear of the first planetary reducer rotates in a direction opposite to the first rotation direction.

[0011] Preferably, the second shift mechanism includes a first shift gear, a second shift gear and a second sliding meshing sleeve, the first shift gear and the second shift gear are coaxially fixed with the first segment and the second segment respectively, the second sliding meshing sleeve is coaxially arranged outside the first shift gear and meshes with the first shift gear, and the second sliding meshing sleeve can slide axially relative to the first shift gear to mesh with or disengage from the second shift gear.

[0012] Preferably, the outer diameters of the sun gears of the first planetary reducer and the second planetary reducer are the same, and the inner diameters of the ring gears are the same.

[0013] Preferably, the first transmission member includes a one-way clutch.

[0014] Preferably, the planet carrier of the first planetary reducer is connected to a driving gear coaxial with the sun gear, and the planet carrier outputs power through the driving gear.

[0015] In a second aspect, the present application provides a dual-motor electric drive axle assembly, comprising the transmission mechanism as described above and two motors, wherein the two motors are respectively connected to the first input shaft and the second input shaft.

[0016] Compared with the prior art, the technical solution of the present application has at least the following beneficial technical effects: 1. The present application sets two input shafts and a first planetary reducer. The power output by the power source is input to the sun gear through the two first input shafts and the second input shaft. The power is input to the planet carrier through the cooperation of the sun gear, the planetary gear and the ring gear, and the power is output through the planet carrier. By setting the first one-way transmission and the Anhe one-way transmission structure, during normal driving, the power source connected to the second input shaft does not output power, and the power source connected to the first input shaft outputs power to the first planetary reducer alone and outputs power through the planetary carrier; when the torque needs to be increased, the power source connected to the second input shaft outputs power to the second input shaft, so that the second input shaft rotates in the same direction as the first input shaft, and the direction is the first rotation direction. At this time, the power of the second input shaft is transmitted to the sun gear of the first planetary reducer, that is, the two power sources output power to the sun gear at the same time, thereby increasing the output torque of the planetary carrier to meet the large torque requirements under conditions such as climbing; and when high-speed driving is required, the power source connected to the second input shaft outputs power to the second input shaft, so that the second input shaft rotates in the opposite direction to the first input shaft, that is, the second input shaft rotates in the direction opposite to the first rotation direction. At this time, the output power of the second input shaft is directly transmitted to the planetary carrier of the first planetary reducer through the one-way transmission structure, and cooperates with the output power of the first input shaft to realize the function of increasing the rotation speed of the planetary carrier of the first planetary reducer, meeting the requirements of high-speed driving conditions. Since two power sources are used, when the power source is an electric motor, the power of a single motor can be designed to be lower, the load rate of a single motor is high when working, the maximum speed of the motor is low, the landing point of the high-efficiency zone is consistent with the operating point of the whole vehicle, the utilization rate of the high-efficiency zone is high, and the secondary reduction transmission efficiency of the planetary reducer is high.

[0017] 2. The present application designs the one-way transmission structure to include a second planetary reducer, and realizes the power transmission between the second input shaft and the planetary carrier of the first planetary reducer through the second planetary reducer. The structural design is simple and occupies a small space of the bridge housing. In addition, the first one-way transmission member adopts a one-way clutch, which can realize the one-way power transmission of the output power of the second input shaft to the sun gear. The second input shaft is set to include a first segment and a second segment, and the first stage and the second segment are connected through a second shifting mechanism. Under the driving condition, the first segment and the second segment are connected. At this time, the power of the second input shaft can be directly input to the sun gear of the first planetary reducer, or transmitted to the planetary carrier of the first planetary reducer through the one-way transmission structure, and the first segment and the second segment are disconnected under the reversing condition. At this time, when the sun gear of the first planetary reducer is driven by the first input shaft to rotate in the direction opposite to the first rotation direction, the power of the sun gear is transmitted to the first segment through the first one-way transmission member and then blocked from being transmitted to the second segment, thereby avoiding the transmission mechanism from being stuck and achieving the purpose of driving the vehicle forward and reverse. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A schematic diagram of the structure of a dual-motor electric drive axle assembly provided by an embodiment of the present invention; Figure 2 A schematic diagram of the transmission structure in a dual-motor electric drive axle assembly provided in an embodiment of the present invention.

[0019] Description of reference numerals: 1. Motor; 2. First input shaft; 3. Second input shaft; 31. First segment; 32. Second segment; 4. First planetary reducer; 5. Second planetary reducer; 6. Sun gear; 7. Planetary gear; 8. Ring gear; 9. Planet carrier; 10. First sliding meshing sleeve; 11. One-way clutch; 12. Driving gear; 13. Driven gear; 14. Second shift mechanism; 141. First shift gear; 142. Second shift gear; 143. Second sliding meshing sleeve. DETAILED DESCRIPTION

[0020] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0022] It will be appreciated that spatial relationship terms such as "under," "beneath," "below," "under," "above," "above," etc., may be used herein to describe the relationship of an element or feature shown in the figures to other elements or features. It will be appreciated that, in addition to the orientations shown in the figures, spatial relationship terms also include different orientations of the device in use and operation. For example, if the device in the accompanying drawings is flipped, an element or feature described as "under other elements" or "under it" or "under it" will be oriented as being "above" the other elements or features. Thus, the exemplary terms "under" and "under" may include both upper and lower orientations. In addition, the device may also include additional orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptors used herein are interpreted accordingly.

[0023] It should be noted that when an element is considered to be "connected" to another element, it can be directly connected to the other element, or connected to the other element through an intermediate element. The "connection" in the following embodiments should be understood as "electrical connection", "communication connection", etc. if the connected circuits, modules, units, etc. have electrical signals or data transmission between each other.

[0024] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" etc. specify the presence of stated features, wholes, steps, operations, components, parts or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts or combinations thereof.

[0025] Reference Figure 1-2 As shown, an embodiment of the present application provides a dual-motor electric drive axle assembly, which includes a transmission mechanism and two motors 1.

[0026] Reference Figure 1-2 As shown, the transmission mechanism includes a first input shaft 2, a second input shaft 3 and a first planetary reducer 4. The first input shaft 2 and the second input shaft 3 are respectively used to connect different power sources. In this embodiment, the power sources are two motors 1, that is, the first input shaft 2 and the second input shaft 3 are respectively connected to the output shafts of the two motors 1, and the output power of the two motors 1 is respectively transmitted to the first input shaft 2 and the second input shaft 3.

[0027] Reference Figure 1-2As shown, the sun gear 6 of the first planetary reducer 4 is coaxially connected with the first input shaft 2 and the second input shaft 3 as a power input end, and the planet carrier 9 is used as an output end for outputting power. Specifically, the first planetary reducer 4 includes a sun gear 6, a planetary gear 7, a planet carrier 9 and a ring gear 8. When installed, the planet carrier 9 and the ring gear 8 are rotatably installed on the bridge housing through bearings, the motor 1 is fixed to the bridge housing, and the output shafts of the two motors 1 are connected to the sun gear 6 of the first planetary reducer 4 through the first input shaft 2 and the second input shaft 3, respectively, so as to input power into the first planetary reducer 4, and the power is output through the planet carrier 9 of the first planetary reducer 4 after being decelerated.

[0028] Reference Figure 1-2 As shown, the first input shaft 2 is coaxially fixed with the sun gear 6 of the first planetary reducer 4, the second input shaft 3 is connected to the sun gear 6 of the first planetary reducer 4 through the first one-way transmission member, and is connected to the planet carrier 9 of the first planetary reducer 4 through the one-way transmission structure. When the second input shaft 3 rotates along the first rotation direction, power is transmitted to the sun gear 6 of the first planetary reducer 4 through the first one-way transmission member, and the power transmission with the one-way transmission structure is disconnected. When the second input shaft 3 rotates in the opposite direction, power is transmitted to the planet carrier 9 of the first planetary reducer 4 through the one-way transmission structure, and the power transmission with the sun gear 6 of the first planetary reducer 4 is disconnected. When the second input shaft 3 rotates in the first rotation direction or rotates in the opposite direction, the direction in which the planet carrier 9 of the first planetary reducer 4 is driven to rotate is the same.

[0029] Through the above arrangement, during normal driving, the power source connected to the second input shaft 3 does not output power, and the power source connected to the first input shaft 2 outputs power to the first planetary reducer 4 and outputs power through the planet carrier 9. When the torque needs to be increased, the power source connected to the second input shaft 3 outputs power to the second input shaft 3, so that the second input shaft 3 rotates in the same direction as the first input shaft 2, and the direction is the first rotation direction. At this time, the power of the second input shaft 3 is transmitted to the sun gear 6 of the first planetary reducer 4, that is, the two power sources simultaneously output power to the sun gear 6, thereby increasing the output torque of the planet carrier 9 and meeting the high torque requirements under conditions such as climbing. When high-speed driving is required, the power source connected to the second input shaft 3 outputs power to the second input shaft 3, so that the second input shaft 3 rotates in the opposite direction to the first input shaft 2, that is, the second input shaft 3 rotates in the direction opposite to the first rotation direction. At this time, the output power of the second input shaft 3 is directly transmitted to the planet carrier 9 of the first planetary reducer 4 through the one-way transmission structure, and cooperates with the output power of the first input shaft 2 to achieve the function of increasing the rotation speed of the planet carrier 9 of the first planetary reducer 4, meeting the requirements of high-speed driving conditions. Since two power sources are used, when the power source is motor 1, the power of a single motor 1 can be designed to be lower, the load rate of the single motor 1 is high when working, the maximum speed of the motor 1 is low, the landing point of the high-efficiency zone is consistent with the operating point of the whole vehicle, the utilization rate of the high-efficiency zone is high, and the secondary reduction transmission efficiency of the planetary reducer is high.

[0030] Reference Figure 1-2 As shown, further, a first shifting mechanism is also provided, the first shifting mechanism is used to connect the bridge housing and the ring gear 8 of the first planetary reducer 4, the first shifting mechanism is used to limit the rotation of the ring gear 8 of the first planetary reducer 4 and can release the restriction, when the input shaft rotates in the direction opposite to the first rotation direction, the power is transmitted to the ring gear 8 of the first planetary reducer 4 through the one-way transmission structure. Specifically, when the first shifting mechanism limits the rotation of the ring gear 8 of the first planetary reducer 4, the power input to the first planetary reducer 4 by the first input shaft 2 and the second input shaft 3 is all output through the planet carrier 9, so as to ensure that the output power of the single motor 1 during normal driving and the output power of the dual motors 1 during climbing are smoothly transmitted to the half shaft. When the first shifting mechanism releases the restriction on the rotation of the ring gear 8 of the first planetary reducer 4, the output power of the second input shaft 3 is input to the ring gear 8 through the one-way transmission structure, so that the rotation direction of the ring gear 8 is the same as the rotation direction of the first input shaft 2, so as to accelerate the rotation speed of the planet carrier 9 of the first planetary reducer 4 through the ring gear 8, increase the output speed, and realize high-speed driving.

[0031] Reference Figure 1-2As shown, the first shift mechanism includes a first sliding engagement sleeve 10, which is used to be connected to the bridge housing and is restricted from rotating relative to the bridge housing, and the first sliding engagement sleeve 10 can slide axially to engage with or disengage from the ring gear 8 of the first planetary reducer 4. Specifically, in this embodiment, the first sliding engagement sleeve 10 coaxially surrounds the outside of the ring gear 8 of the first planetary reducer 4, a fixed engagement sleeve that is constantly engaged with the first sliding engagement sleeve 10 is fixed on the bridge housing, and meshing teeth for cooperating with the first sliding engagement sleeve 10 are provided outside the ring gear 8, and the first sliding engagement sleeve 10 can slide axially relative to the bridge housing to engage with or disengage from the meshing teeth outside the ring gear 8, so as to restrict the rotation of the ring gear 8 through the cooperation of the first sliding engagement sleeve 10 and the fixed engagement sleeve, or release the restriction. In other embodiments, the position of the first sliding engagement sleeve 10 can be set according to actual conditions. For example, the first sliding engagement sleeve 10 is set on the inner side of the gear ring 8. The first sliding engagement sleeve 10 can slide to directly engage with or disengage the teeth on the inner side of the gear ring 8.

[0032] Reference Figure 1-2 As shown, further, the one-way transmission structure includes a second planetary reducer 5 and a second one-way transmission member, the sun gear 6 of the second planetary reducer 5 is coaxial with the sun gear 6 of the first planetary reducer 4, the planet carrier 9 of the second planetary reducer 5 is used to be fixed to the bridge housing, the ring gear 8 of the second planetary reducer 5 is fixed to the ring gear 8 of the first planetary reducer 4, the second input shaft 3 is connected to the sun gear 6 of the second planetary reducer 5 through the second one-way transmission member, and when the second input shaft 3 rotates in the direction opposite to the first rotation direction, the power is transmitted to the sun gear 6 of the second planetary reducer 5 through the second one-way transmission member. Under high-speed driving conditions, the first shift mechanism contacts the restriction on the rotation of the ring gear 8 of the first planetary reducer 4, the second input shaft 3 outputs power to the sun gear 6 of the second planetary reducer 5, the power is transmitted to the ring gear 8 through the planetary gear 7 of the second planetary reducer 5, and the ring gear 8 of the second planetary reducer 5 outputs power to the ring gear 8 of the first planetary reducer 4, and then accelerates the rotation of its planet carrier 9 through the ring gear 8 of the first planetary reducer 4, so as to meet the high-speed driving requirements through the two motors 1. The first planetary reducer 4 and the second planetary reducer 5 are both two-stage reduction gears, with high power transmission efficiency and high energy utilization rate.

[0033] Reference Figure 1-2 As shown, in this embodiment, the ring gear 8 of the first planetary reducer 4 and the second planetary reducer 5 are integrally formed, or the first planetary reducer 4 and the second planetary reducer 5 share the ring gear 8; the outer diameter of the sun gear 6 of the first planetary reducer 4 and the second planetary reducer 5 is the same, and the inner diameter of the ring gear 8 is the same, that is, the first planetary reducer 4 and the second planetary reducer 5 have the same reduction ratio.

[0034] Reference Figure 1-2As shown, further, the first one-way transmission member and the second one-way transmission member both adopt a one-way clutch 11, which can achieve the purpose of unidirectional transmission of the output power of the second input shaft 3 to the sun gear 6 of the first planetary reducer 4 or the sun gear 6 of the second planetary reducer 5.

[0035] At the same time, in order to avoid the mechanism from getting stuck under the reversing condition, the second input shaft 3 is configured to include a first segment 31 and a second segment 32. The first segment 31 is connected to the sun gear 6 of the first planetary reducer 4 through a first one-way transmission member, and the second segment 32 is connected to the planet carrier 9 of the first planetary reducer 4 through a one-way transmission structure. The first segment 31 can be selectively connected or disconnected with the second segment 32 through a second shifting mechanism 14, and is suitable for disconnecting the first segment 31 and the second segment 32 through the second shifting mechanism 14 when the sun gear 6 of the first planetary reducer 4 rotates in a direction opposite to the first rotation direction.

[0036] Specifically, the second shift mechanism 14 includes a first shift gear 141, a second shift gear 142 and a second sliding meshing sleeve 143. The first shift gear 141 and the second shift gear 142 are coaxially fixed to the first segment 31 and the second segment 32 respectively. The second sliding meshing sleeve 143 is coaxially arranged outside the first shift gear 141 and meshes with the first shift gear 141, and the second sliding meshing sleeve 143 can slide axially relative to the first shift gear 141 until it meshes with or disengages from the second shift gear 142.

[0037] Through the above arrangement, under normal driving conditions, the second sliding engagement sleeve 143 is meshed with the first shift gear 141 and the second shift gear 142 at the same time, so that the first segment 31 and the second segment 32 are connected. At this time, the power of the second input shaft 3 can be directly input into the sun gear 6 of the first planetary reducer 4, or transmitted to the planet carrier 9 of the first planetary reducer 4 through the one-way transmission structure. Under reversing conditions, the second sliding engagement sleeve 143 is disengaged from the second shift gear 142, the first segment 31 and the second segment 32 are disconnected, the first input shaft 2 rotates in the direction opposite to the first rotation direction, and the power is blocked after being transmitted to the first segment 31 through the sun gear 6 of the first planetary reducer 4 and the first one-way transmission member, and the second segment 32 does not rotate, thereby avoiding the mechanism from being stuck, that is, reversing is achieved by the single motor 1 in cooperation with the first planetary reducer 4. Therefore, the transmission structure can meet the transmission requirements of low-speed and high-speed driving, large torque climbing and reversing.

[0038] Reference Figure 1-2 As shown, further, in order to facilitate the planetary carrier 9 of the first planetary reducer 4 to output power, the planetary carrier 9 of the first planetary reducer 4 is connected to a driving gear 12 coaxial with the sun gear 6 , and the planetary carrier 9 outputs power through the driving gear 12 .

[0039] Reference Figure 1 As shown, further, the dual-motor 1 electric drive axle assembly of this embodiment also includes a driven gear 13, which is meshed with the driving gear 12 and has a diameter larger than the diameter of the driving gear 12. The driven gear 13 is used to be rotatably mounted on the bridge housing to further reduce the output power of the driving gear 12 and output it.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A transmission mechanism, characterized in that: include: The first input shaft (2) and the second input shaft (3) are respectively used to connect to different power sources; A first planetary reducer (4), wherein the sun gear (6) is coaxially connected to the first input shaft (2) and the second input shaft (3) as a power input end, and the planet carrier (9) is used as an output end for outputting power. The second input shaft (3) is connected to the sun gear (6) of the first planetary reducer (4) through a first one-way transmission member, and is connected to the planet carrier (9) of the first planetary reducer (4) through a one-way transmission structure. When the second input shaft (3) rotates in a first rotation direction, power is transmitted to the sun gear (6) of the first planetary reducer (4) through the first one-way transmission member, and the power transmission with the one-way transmission structure is disconnected. When the second input shaft (3) rotates in the reverse direction, power is transmitted to the planet carrier (9) of the first planetary reducer (4) through the one-way transmission structure, and the power transmission with the sun gear (6) of the first planetary reducer (4) is disconnected. When the second input shaft (3) rotates in the first rotation direction or in the reverse direction, the planet carrier (9) of the first planetary reducer (4) is driven to rotate in the same direction.

2. The transmission mechanism according to claim 1, characterized in that: The invention also comprises a first shifting mechanism, the first shifting mechanism being used to connect the bridge housing and the ring gear (8) of the first planetary reducer (4), the first shifting mechanism being used to limit the rotation of the ring gear (8) of the first planetary reducer (4) and being able to release the restriction, and when the second input shaft (3) rotates in a direction opposite to the first rotation direction, power is transmitted to the ring gear (8) of the first planetary reducer (4) through the one-way transmission structure.

3. The transmission mechanism according to claim 2, characterized in that: The one-way transmission structure comprises a second planetary reducer (5) and a second one-way transmission member, the sun gear (6) of the second planetary reducer (5) is coaxial with the sun gear (6) of the first planetary reducer (4), the planet carrier (9) of the second planetary reducer (5) is used to be fixed to the bridge housing, the ring gear (8) of the second planetary reducer (5) is fixed to the ring gear (8) of the first planetary reducer (4), the second input shaft (3) is connected to the sun gear (6) of the second planetary reducer (5) through the second one-way transmission member, and when the second input shaft (3) rotates in a direction opposite to the first rotation direction, power is transmitted to the sun gear (6) of the second planetary reducer (5) through the second one-way transmission member.

4. The transmission mechanism according to claim 2, characterized in that: The first shifting mechanism comprises a first sliding engagement sleeve (10), which is used to be connected to the bridge housing and is restricted from rotating relative to the bridge housing, and the first sliding engagement sleeve (10) can slide axially to engage with or disengage from the ring gear (8) of the first planetary reducer (4).

5. The transmission mechanism according to claim 1, characterized in that: The second input shaft (3) comprises a first segment (31) and a second segment (32); the first segment (31) is connected to the sun gear (6) of the first planetary reducer (4) through the first one-way transmission member; the second segment (32) is connected to the planet carrier (9) of the first planetary reducer (4) through the one-way transmission structure; the first segment (31) can be selectively connected to or disconnected from the second segment (32) through a second shifting mechanism (14); and the first segment (31) and the second segment (32) are disconnected through the second shifting mechanism (14) when the sun gear (6) of the first planetary reducer (4) rotates in a direction opposite to the first rotation direction.

6. The transmission mechanism according to claim 5, characterized in that: The second shift mechanism (14) comprises a first shift gear (141), a second shift gear (142) and a second sliding engagement sleeve (143); the first shift gear (141) and the second shift gear (142) are coaxially fixed to the first segment (31) and the second segment (32) respectively; the second sliding engagement sleeve (143) is coaxially arranged outside the first shift gear (141) and meshes with the first shift gear (141); and the second sliding engagement sleeve (143) can slide axially relative to the first shift gear (141) to mesh with or disengage from the second shift gear (142).

7. The transmission mechanism according to claim 3, characterized in that: The sun gears (6) of the first planetary reducer (4) and the second planetary reducer (5) have the same outer diameter, and the ring gears (8) have the same inner diameter.

8. The transmission mechanism according to claim 1, characterized in that: The first transmission member comprises a one-way clutch (11).

9. The transmission mechanism according to claim 1, characterized in that: The planet carrier (9) of the first planetary reducer (4) is connected to a driving gear (12) coaxial with the sun gear (6), and the planet carrier (9) outputs power through the driving gear (12).

10. A dual-motor electric drive axle assembly, characterized in that: It comprises a transmission mechanism as claimed in any one of claims 1 to 9 and two motors (1), wherein the two motors (1) are respectively connected to the first input shaft (2) and the second input shaft (3).

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