A coaxial multi-speed electric drive axle system and vehicle

Abstract

The application relates to a coaxial multi-gear electric drive axle system and a vehicle, two gear shifting mechanisms are arranged, three gears can be switched to meet the driving requirements under different working conditions. One gear is used for low-speed high-torque working conditions, the second gear is used for medium-speed working conditions, and the third gear is used for high-speed working conditions, so that the speed ratio coverage range of the system is effectively expanded. Further, the gear transmission mechanism and the planetary gear assembly in the application adopt a coaxial arrangement mode, the structure is compact, the transmission efficiency is high, the meshing relationship between the gear sleeves and the combined gears of the two gear shifting mechanisms is reasonably designed, smooth switching between the three gears is realized, gear shifting impact is avoided, and the driving comfort of the whole vehicle is improved.

Description

Technical Field

[0001] This invention relates to the field of vehicle powertrain technology, and in particular to a coaxial multi-speed electric drive axle system and vehicle. Background Technology

[0002] In the field of pure electric vehicles, the transmission efficiency and structural design of the electric drive axle system directly affect the overall vehicle performance. Currently, one type of electric drive axle system on the market employs a two-stage planetary gear set combined with a clutch and brake for gear shifting, such as the "two-speed coaxial electric drive axle" disclosed in Chinese patent document CN115027256A. This scheme achieves two-speed transmission through a shifting mode using two clutches and one brake. While this design can achieve basic gear shifting functionality, it has several limitations: First, the two-stage planetary gear set structure is difficult to manufacture, resulting in high production costs; second, this scheme can only achieve two-speed transmission, making it difficult to meet the diverse transmission ratio requirements of vehicles under different operating conditions; and third, its complex structure is not conducive to a compact overall layout.

[0003] Therefore, the industry urgently needs an electric drive axle system that is simple in structure, low in manufacturing cost, and capable of multi-gear transmission to meet the high-efficiency operation requirements of pure electric vehicles under different operating conditions. Summary of the Invention

[0004] This invention discloses a coaxial multi-speed electric drive axle system and vehicle, aiming to solve the technical problems existing in the prior art.

[0005] The present invention adopts the following technical solution:

[0006] On one hand, embodiments of the present invention provide a coaxial multi-speed electric drive bridge system, which includes a motor, a main gearbox and an auxiliary gearbox. The main gearbox is provided with a parallel shaft transmission mechanism and a first shifting mechanism, and the auxiliary gearbox is provided with a planetary gear set assembly and a second shifting mechanism.

[0007] The parallel shaft transmission mechanism includes an input shaft, an intermediate shaft, and a sun gear shaft. The input shaft is arranged parallel to the intermediate shaft and coaxially with the sun gear shaft.

[0008] The input end of the input shaft is connected to the motor drive, the output end of the input shaft is connected to the intermediate shaft drive, and the output end of the input shaft is also provided with a first engagement tooth adjacent to the first shifting mechanism;

[0009] The output end of the intermediate shaft is connected to the first driven gear, and the output end of the first driven gear is provided with a second engagement tooth adjacent to the first shifting mechanism and a third engagement tooth adjacent to the second shifting mechanism;

[0010] The input end of the sun gear shaft is equipped with a first shifting mechanism, and the sun gear shaft is connected to the planetary gear set assembly for transmission.

[0011] The planetary gearbox assembly includes a planet carrier, and a second shifting mechanism is provided at the input end of the planet carrier;

[0012] The first shifting mechanism can selectively engage with the first or second engagement tooth, and the second shifting mechanism can selectively engage or disengage with the third engagement tooth. Through the cooperation of the first and second shifting mechanisms, the transmission of three forward gears is realized.

[0013] As a preferred technical solution, a constant mesh gear and a first driving gear are fixedly connected on the intermediate shaft. The constant mesh gear meshes with the input shaft to realize the transmission connection between the input shaft and the intermediate shaft; the first driving gear meshes with the first driven gear.

[0014] As a preferred technical solution, the first driven gear is loosely fitted on the sun gear shaft, and the second and third engaging teeth are fixedly connected to the first driven gear.

[0015] As a preferred technical solution, the first shifting mechanism includes a first gear hub and a first gear sleeve. The first gear hub is fixedly connected to the sun gear shaft, and the first gear sleeve can slide along the axial direction of the first gear hub. The first gear sleeve can selectively engage with a first engagement tooth or a second engagement tooth.

[0016] As a preferred technical solution, the second shifting mechanism includes a second gear hub and a second sliding sleeve. The second gear hub is fixedly connected to the planetary carrier, and the second gear sleeve can slide along the axial direction of the second gear hub. The second gear sleeve can selectively engage with the third engagement tooth.

[0017] As a preferred technical solution, the planetary gear assembly also includes a ring gear, a sun gear, and planet gears. The sun gear is fixedly connected to the sun gear shaft, and the planet gears are mounted on the planet carrier. The planet carrier is fixedly connected to the differential assembly.

[0018] As a preferred technical solution, when in the first gear transmission state, the first gear sleeve engages with the second engagement tooth, and the second gear sleeve separates from the third engagement tooth.

[0019] As a preferred technical solution, when in the second gear transmission state, the first gear sleeve and the second engagement tooth remain engaged, and the second gear sleeve and the third engagement tooth engage.

[0020] As a preferred technical solution, when in the three-speed transmission state, the first tooth sleeve engages with the first engagement tooth, and the second tooth sleeve separates from the third engagement tooth.

[0021] On the other hand, embodiments of the present invention also provide a vehicle, the vehicle including the coaxial multi-speed electric drive axle system as described in any of the preceding claims.

[0022] One embodiment of the above invention has the following advantages or beneficial effects:

[0023] This invention primarily provides a coaxial multi-speed electric drive axle system and a vehicle equipped with this system. Compared with existing technologies, the electric drive axle system of this invention, by setting two shifting mechanisms, can achieve three-speed switching to meet the driving requirements under different operating conditions. The first speed is used for low-speed, high-torque conditions, the second for medium-speed conditions, and the third for high-speed conditions, effectively expanding the system's speed ratio coverage.

[0024] Furthermore, in this embodiment of the invention, the gear transmission mechanism and the planetary gear set are arranged coaxially, resulting in a compact structure and high transmission efficiency. By rationally designing the meshing relationship between the gear sleeves and engaging teeth of the two shifting mechanisms, smooth switching between the three gears is achieved, avoiding shifting shock and improving the overall driving comfort of the vehicle.

[0025] Compared to existing single-speed or dual-speed electric drive axles, this invention not only improves transmission efficiency but also reduces system manufacturing and maintenance costs. Furthermore, the system exhibits good versatility and adaptability, making it widely applicable to various types of new energy vehicles and significantly contributing to the development of the new energy vehicle industry. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below, forming part of the present invention. The illustrative embodiments of the present invention and their descriptions explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0027] Figure 1 This is a schematic diagram of a coaxial multi-speed electric drive bridge system provided in one embodiment of the present invention;

[0028] Figure 2 A schematic diagram of the power flow of a first-speed transmission provided in one embodiment of the present invention;

[0029] Figure 3 This is a schematic diagram of the power flow of a two-speed transmission according to an embodiment of the present invention;

[0030] Figure 4 This is a schematic diagram of the power flow of a three-speed transmission according to an embodiment of the present invention.

[0031] Explanation of reference numerals in the attached figures:

[0032] Motor 11, input shaft 12, first engagement gear 13, intermediate shaft 14, constant mesh gear 15, first driving gear 16, first driven gear 17, second engagement gear 18, third engagement gear 19, first shift actuator 21, first shift fork 22, first gear sleeve 23, first gear hub 24, sun gear shaft 31, sun gear 32, first planet gear 33, second planet gear 34, planet carrier 35, ring gear 36, second shift actuator 41, second shift fork 42, second gear sleeve 43, second gear hub 44, differential assembly 51, left wheel end 61, right wheel end 62. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. In the description of this invention, it should be noted that the term "or" is generally used to include the meaning of "and / or," unless otherwise expressly indicated.

[0034] In the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0035] Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0036] In the traditional pure electric heavy commercial vehicle sector, existing electric drive axle systems are mostly single-speed or dual-speed structures, which are difficult to meet the diverse speed and torque requirements of vehicles under different operating conditions. Among them, single-speed electric drive axle systems have a simple structure but a fixed speed ratio, making it difficult to achieve ideal driving effects under low-speed, high-torque and high-speed operating conditions. While dual-speed electric drive axle systems improve driving performance to some extent, the speed ratio coverage is still limited, and existing dual-speed electric drive axles generally suffer from problems such as complex structure, large shift shock, and high manufacturing costs.

[0037] To address the problems existing in the prior art, this invention provides a coaxial multi-speed electric drive axle system. By arranging the gear transmission mechanism and the planetary gear set coaxially and setting two shifting mechanisms, three gears can be switched to meet the drive requirements under different working conditions.

[0038] refer to Figure 1In a preferred embodiment, the coaxial multi-speed electric drive bridge system includes a motor 11, a main gearbox and an auxiliary gearbox. The main gearbox is provided with a parallel shaft transmission mechanism and a first shifting mechanism, and the auxiliary gearbox is provided with a planetary gear set assembly, a second shifting mechanism and a differential assembly 51. It should be noted that the aforementioned gear transmission mechanism is also the parallel shaft transmission mechanism arranged in the main gearbox.

[0039] Specifically, the main gearbox and auxiliary gearbox described above are used to perform different transmission functions. The main gearbox, as the first-stage transmission part, mainly includes a power transmission device located at the input end of the motor 11. The parallel shaft transmission mechanism is responsible for the primary transmission and speed regulation of the motor 11's power. The auxiliary gearbox, as the second-stage transmission part, achieves further power transmission and speed ratio regulation through the planetary gear set assembly, and finally outputs power through the differential assembly 51. The compartmentalized design of this embodiment not only facilitates the overall layout and assembly, but also promotes heat dissipation and lubrication of each transmission component, and also facilitates later maintenance.

[0040] Furthermore, in this embodiment of the invention, the motor 11, planetary gear set assembly and differential assembly 51 are configured in a coaxial structure. This arrangement makes the power transmission path more direct and the structure of the entire transmission system more compact, greatly reducing the size of the electric drive axle system, so as to facilitate the layout and installation of the whole vehicle.

[0041] In a preferred embodiment, the parallel shaft drive mechanism is configured as a two-shaft parallel shaft, including an input shaft 12, an intermediate shaft 14, and a sun gear shaft 31. In terms of spatial arrangement, the input shaft 12 and the intermediate shaft 14 are arranged parallel to each other, while the input shaft 12 and the sun gear shaft 31 are arranged coaxially.

[0042] Preferably, the input end of the input shaft 12 is fixedly connected to the motor 11, and the two are connected by transmission. The output end of the input shaft 12 is connected by transmission to the intermediate shaft 14. The output end of the input shaft 12 is also provided with a first engagement tooth 13 adjacent to the first shifting mechanism.

[0043] Preferably, a constant mesh gear 15 and a first driving gear 16 are fixedly connected on the intermediate shaft 14. The constant mesh gear 15 meshes with the input shaft 12 to realize the transmission connection between the input shaft 12 and the intermediate shaft 14. The first driving gear 16 meshes with the first driven gear 17, and the two are connected in transmission. The first driven gear 17 is loosely fitted on the sun gear shaft 31. The second engagement gear 18 and the third engagement gear 19 are fixedly connected on the first driven gear 17. The second engagement gear 18 is located near the first shifting mechanism, and the third engagement gear 19 is located near the second shifting mechanism. When the first shifting mechanism engages with the second engagement gear 18, power can be transmitted from the first driven gear 17 to the sun gear shaft 31. When the first shifting mechanism engages with the first engagement gear 19, the first driven gear 17 can rotate freely on the sun gear shaft 31. At this time, the intermediate shaft 14 does not transmit power.

[0044] During power transmission, the high-speed rotation output of motor 11 requires multi-stage gear transmission to reduce the speed and increase the torque. First, a first-stage reduction is achieved through the constant-mesh gear 15 on the input shaft 12 and intermediate shaft 14. Then, a second-stage reduction is achieved through the meshing of the first driving gear 16 and the first driven gear 17 on the intermediate shaft 14. This multi-stage reduction design gradually reduces the high speed of motor 11 to a speed range suitable for vehicle driving, while correspondingly increasing the output torque.

[0045] Furthermore, by rationally designing the gear ratio of the first driving gear 16 and the first driven gear 17, the reduction ratio can be precisely controlled, ensuring that the final output speed and torque meet the requirements of the vehicle's power performance. The engagement teeth at the output end of the first driven gear 17 further combine the reduction function with the shifting function, improving the integration of the entire transmission system. It should be noted that in this embodiment, the reduction ratio between the constant mesh gear 15 on the input shaft 12 and the intermediate shaft 14, and the reduction ratio between the first driving gear 16 and the first driven gear 17, are not specifically limited; those skilled in the art can make adaptive adjustments according to actual needs.

[0046] Preferably, a first shifting mechanism is provided at the input end of the sun gear shaft 31. The first shifting mechanism includes a first shifting actuator 21, a first shift fork 22, a first gear hub 24, and a first gear sleeve 23. The first gear hub 24 is fixedly connected to the sun gear shaft 31, and the first gear sleeve 23 can slide axially along the first gear hub 24. When shifting is required, the first shifting actuator 21 drives the first shift fork 22, which in turn drives the first gear sleeve 23 to move axially, allowing it to selectively engage with the first engagement tooth 13 or the second engagement tooth 18. When the first gear sleeve 23 engages with the first engagement tooth 13, power is directly transmitted from the input shaft 12 to the sun gear shaft 31. When the first gear sleeve 23 engages with the second engagement tooth 18, power is transmitted to the sun gear shaft 31 through the transmission path of the intermediate shaft 14, the first driving gear 16, and the first driven gear 17. Through the precise control of the first shifting actuator 21, flexible switching between different gears can be achieved to meet the power transmission requirements under different working conditions.

[0047] Preferably, the other end of the sun gear shaft 31 is connected to the planetary gear assembly for transmission. The planetary gear assembly includes a sun gear 32, planet gears, a planet carrier 35, and a ring gear 36.

[0048] The sun gear 32 is rigidly connected to the sun gear shaft 31 to ensure synchronous rotation and reliable power transmission. The planetary gears include a double-linked first planetary gear 33 and a second planetary gear 34, which are rigidly connected to each other and loosely fitted on the planet carrier 35. The ring gear 36 is rigidly connected to the housing. The input end of the planet carrier 35 is equipped with a second shifting mechanism to realize the switching of power transmission paths under different working conditions. The output end of the planet carrier 35 is rigidly connected to the differential assembly 51 to ensure that the final power can be transmitted to the wheels through the left and right half shafts.

[0049] Preferably, the second shifting mechanism includes a second shifting actuator 41, a second shifting fork 42, a second gear hub 44, and a second sliding sleeve. The second gear hub 44 is fixedly connected to the planetary carrier 35, and the second gear sleeve 43 can slide axially along the second gear hub 44. When shifting is required, the second shifting actuator 41 drives the second shifting fork 42, thereby causing the second gear sleeve 43 to move axially, so that the second gear sleeve 43 can selectively engage or disengage with the third engagement tooth 19. Through the cooperation of the first shifting mechanism and the second shifting mechanism, the transmission of three forward gears is realized.

[0050] Specifically, when the second gear sleeve 43 engages with the third engagement tooth 19, power is transmitted from the sun gear shaft 31 to the sun gear 32. The sun gear 32 drives the first planet gear 33 and the second planet gear 34 to rotate. Since the second gear sleeve 43 engages with the third engagement tooth 19, the planetary gear set assembly forms a whole. At this time, the sun gear 32, planet gears, and planet carrier 35 rotate synchronously as a whole. The planetary gear set assembly operates with a 1:1 transmission ratio. After passing through the planetary gear set assembly, the power is finally output from the planet carrier 35 to the differential assembly 51.

[0051] When the second gear sleeve 43 separates from the third engagement gear 19, the power is transmitted from the sun gear shaft 31 to the sun gear 32, and then through the sun gear 32 to the first planet gear 33 and the second planet gear 34. Since there is no locking effect at this time, each component of the planetary gear set can work according to the motion law of planetary gear transmission. After the power is reduced by the planetary gear set assembly, it is output by the planet carrier 35 to the differential assembly 51 to achieve a certain reduction ratio.

[0052] refer to Figure 2 In a preferred embodiment, when in first gear, the first gear sleeve 23 engages with the second engagement tooth 18, that is, the first shifting mechanism selects a transmission path with a large reduction ratio. The power is transmitted to the first driven gear 17 through the input shaft 12, intermediate shaft 14, and first driving gear 16, undergoing two-stage reduction. The second gear sleeve 43 separates from the third engagement tooth 19, at which point the planetary gear set assembly works according to the normal planetary gear pattern. In this way, the maximum reduction ratio is obtained through three-stage reduction (the first two stages of gear shifting in the main gearbox and the planetary gear set assembly reduction in the auxiliary gearbox) to meet the demand for high torque in first gear.

[0053] refer to Figure 2 The red part indicates the direction of power flow. Specifically, in the first gear transmission state, the system's power is input by the motor 11, transmitted to the constant mesh gear 15 via the input shaft 12, then transmitted to the first driven gear 17 via the intermediate shaft 14, and then transmitted to the sun gear shaft 31 via the first gear sleeve 23 and the first gear hub 24 in the first gear shifting mechanism. The power is then transmitted to the first planet gear 33 and the second planet gear 34 via the sun gear in the sun gear shaft 31, and then transmitted to the differential assembly 51 via the planet carrier 35. The power output from the differential assembly 51 is transmitted to the left wheel end 61 and the right wheel end 62 via the left half shaft and the right half shaft, respectively.

[0054] refer to Figure 3 In a preferred embodiment, when in second gear, the first gear sleeve 23 and the second gear sleeve 43 remain engaged, that is, the first shifting mechanism still maintains a transmission path with a large reduction ratio. The second gear sleeve 43 engages with the third engagement tooth 19, so that the planetary gear set assembly forms an overall 1:1 transmission. In this way, a medium reduction ratio is obtained through the 1:1 transmission of the front-stage gear change and the planetary gear set.

[0055] refer to Figure 3 The red part indicates the direction of power flow. Specifically, in the second gear transmission state, the system's power is input by the motor 11, transmitted to the constant meshing gear 15 via the input shaft 12, then transmitted to the first driven gear 17 via the intermediate shaft 14, and then transmitted to the sun gear shaft 31 via the first gear sleeve 23 and the first gear hub 24 in the first shifting mechanism. Since the second gear sleeve 43 and the third engagement gear 19 are engaged, the planetary gear assembly is formed as a whole. The power is directly transmitted to the differential assembly 51 via the planet carrier 35 as a whole. Finally, the power is transmitted to the left wheel end 61 and the right wheel end 62 via the left half shaft and the right half shaft, respectively.

[0056] refer to Figure 4 In a preferred embodiment, when in the third gear transmission state, the first gear sleeve 23 engages with the first engagement tooth 13, that is, at this time the first shifting mechanism switches to the direct drive path to reduce the reduction ratio; the second gear sleeve 43 separates from the third engagement tooth 19 again, and the planetary gear assembly resumes the reduction effect of the planetary gears. At this time, a smaller reduction ratio can be obtained through direct drive and planetary gear reduction.

[0057] refer to Figure 4The red part indicates the direction of power flow. Specifically, in the third gear transmission state, the power is input from the motor 11, and is directly transmitted to the sun gear shaft 31 through the first engagement gear 13, the first gear sleeve 23, and the first gear hub 24. Then it is transmitted to the first planet gear 33 and the second planet gear 34 through the sun gear 32, and to the differential assembly 51 through the planet carrier 35. Finally, it is split through the left half shaft and the right half shaft respectively, so that the power flow of the three gears is transmitted to the left wheel end 61 and the right wheel end 62 respectively.

[0058] In the above embodiments, by rationally designing the working state of the planetary gearbox assembly and the transmission path of the main gearbox, three different transmission ratios are achieved. First gear utilizes a three-stage reduction gear to obtain the maximum reduction ratio; second gear achieves a medium reduction ratio through main gearbox reduction plus a 1:1 planetary gearbox transmission; and third gear uses direct drive plus planetary gearbox reduction to obtain a smaller reduction ratio. Compared with existing technologies, the transmission structure provided in this embodiment significantly reduces the number of transmission parts, and the rational arrangement of the transmission paths for each gear effectively reduces power loss and ensures high transmission efficiency.

[0059] In one embodiment of the present invention, a vehicle is also provided, which is equipped with the aforementioned coaxial multi-speed electric drive axle system. Preferably, the vehicle in this embodiment is a purely electric commercial vehicle, such as an electric truck, electric bus, electric transport vehicle, or electric tractor. Based on the aforementioned electric drive axle system, the vehicle can meet the driving requirements of different working conditions.

[0060] Although exemplary embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above exemplary embodiments are merely illustrative and are not intended to limit the scope of this application. Various changes and modifications can be made therein by those skilled in the art without departing from the scope and spirit of this application. All such changes and modifications are intended to be included within the scope of this application as claimed in the appended claims.

[0061] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of this application may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0062] Similarly, it should be understood that, in order to streamline this application and aid in understanding one or more of the various inventive aspects, features of this application may sometimes be grouped together in a single embodiment, figure, or description thereof in the description of exemplary embodiments of this application. However, this approach should not be construed as reflecting an intention that the claimed application requires more features than are expressly recited in each claim. Rather, as reflected in the corresponding claims, its inventive point lies in solving the corresponding technical problem with features fewer than all features of a single disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into that detailed description, wherein each claim itself is a separate embodiment of this application.

[0063] Those skilled in the art will understand that, apart from the mutual exclusion of features, all features disclosed in this specification (including the accompanying claims, abstract, and drawings) and all processes or elements of any method or apparatus so disclosed can be combined in any combination. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) may be replaced by an alternative feature serving the same, equivalent, or similar purpose.

Claims

1. A coaxial multi-speed electric drive bridge system, characterized in that, It includes a motor, a main housing, and an auxiliary housing. The main housing is equipped with a parallel shaft transmission mechanism and a first shifting mechanism, and the auxiliary housing is equipped with a planetary gear set assembly and a second shifting mechanism. The parallel shaft transmission mechanism includes an input shaft, an intermediate shaft, and a sun gear shaft. The input shaft is arranged parallel to the intermediate shaft and coaxially with the sun gear shaft. The input end of the input shaft is connected to the motor drive, and the output end of the input shaft is connected to the intermediate shaft drive. The output end of the input shaft is also provided with a first engagement tooth adjacent to the first shifting mechanism. The output end of the intermediate shaft is connected to the first driven gear, and the output end of the first driven gear is provided with a second engagement tooth adjacent to the first shifting mechanism and a third engagement tooth adjacent to the second shifting mechanism; The input end of the sun gear shaft is provided with the first shifting mechanism, and the sun gear shaft is connected to the planetary gear assembly for transmission. The planetary gear transmission assembly includes a planet carrier, and the input end of the planet carrier is provided with the second shifting mechanism; The first shifting mechanism can selectively engage with the first or second engagement tooth, and the second shifting mechanism can selectively engage or disengage with the third engagement tooth. Through the cooperation of the first and second shifting mechanisms, the transmission of three forward gears is realized. When in first gear, the first shifting mechanism selects a transmission path with a larger reduction ratio, and the second shifting mechanism makes the planetary gear assembly work according to the normal planetary gear pattern. The system obtains the maximum reduction ratio through three-stage reduction. When in second gear, the first shifting mechanism selects a transmission path with a larger reduction ratio, and the second shifting mechanism enables the planetary gear assembly to form a 1:1 transmission as a whole, so that the system obtains a medium reduction ratio. When in third gear, the first shifting mechanism selects the direct drive path, and the second shifting mechanism makes the planetary gear assembly work according to the normal planetary gear pattern, so that the system obtains the minimum reduction ratio.

2. The coaxial multi-speed electric drive bridge system according to claim 1, characterized in that, A constant mesh gear and a first driving gear are fixedly connected on the intermediate shaft. The constant mesh gear meshes with the input shaft to realize the transmission connection between the input shaft and the intermediate shaft. The first driving gear meshes with the first driven gear.

3. The coaxial multi-speed electric drive bridge system according to claim 2, characterized in that, The first driven gear is loosely fitted on the sun gear shaft, and the second and third engagement teeth are fixedly connected to the first driven gear.

4. The coaxial multi-speed electric drive bridge system according to claim 3, characterized in that, The first shifting mechanism includes a first gear hub and a first gear sleeve. The first gear hub is fixedly connected to the sun gear shaft, and the first gear sleeve can slide along the axial direction of the first gear hub. The first gear sleeve can selectively engage with the first engagement tooth or the second engagement tooth.

5. The coaxial multi-speed electric drive bridge system according to claim 4, characterized in that, The second shifting mechanism includes a second gear hub and a second gear sleeve. The second gear hub is fixedly connected to the planetary carrier, and the second gear sleeve can slide along the axial direction of the second gear hub. The second gear sleeve can selectively engage with the third engagement tooth.

6. The coaxial multi-speed electric drive bridge system according to claim 5, characterized in that, The planetary gear assembly also includes a ring gear, a sun gear, and planet gears. The sun gear is driven and fixedly connected to the sun gear shaft. The planet gears are mounted on the planet carrier, and the planet carrier is fixedly connected to the differential assembly.

7. The coaxial multi-speed electric drive bridge system according to claim 6, characterized in that, When in first gear, the first toothed sleeve engages with the second engaging tooth, and the second toothed sleeve separates from the third engaging tooth.

8. The coaxial multi-speed electric drive bridge system according to claim 6, characterized in that, When in the second gear transmission state, the first toothed sleeve is engaged with the second engagement tooth, and the second toothed sleeve is engaged with the third engagement tooth.

9. The coaxial multi-speed electric drive bridge system according to claim 6, characterized in that, When in the third gear transmission state, the first gear sleeve engages with the first engagement tooth, and the second gear sleeve separates from the third engagement tooth.

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

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