Electric drive axle and electric truck

Abstract

The utility model relates to an electric drive axle which is used for an electric truck, the electric drive axle is provided with a main drive motor, a speed reducer assembly and a differential mechanism assembly, the speed reducer assembly is provided with a first-level speed reduction level, a first-gear transmission mechanism, a second-gear transmission mechanism, a third-gear transmission mechanism, a first gear shifting mechanism and a second gear shifting mechanism, the first speed reduction stage is composed of a first speed reduction driving gear and a first speed reduction driven gear which are meshed with each other, the first speed reduction driving gear is fixedly supported on a motor shaft, and the first-gear transmission mechanism is composed of a planetary gear reducer, a first driving gear and a first driven gear. The second-gear transmission mechanism is composed of a planet carrier of the planetary gear reducer, a first driving gear and a first driven gear, and the third-gear transmission mechanism is composed of a second driving gear and a second driven gear, the torque of the main drive motor is transmitted to the differential mechanism assembly through the first-stage speed reduction stage and the first-gear transmission mechanism or the second-gear transmission mechanism or the third-gear transmission mechanism.

Description

Electric drive axles and electric trucks Technical Field

[0001] This utility model relates to an electric drive axle and an electric truck having such an electric drive axle. Background Technology

[0002] In the electric drive architectures that are currently the main types of electric trucks, electric motors with speeds of 12,000 RPM or higher are typically used. Motors in this speed range usually require three or more stages of transmission mechanisms and use planetary gear reducers or planetary gear sub-boxes to achieve gear shifting. In these systems, the ring gear is fixed, the sun gear is used as the driving transmission component, and the planetary gears are used as the driven transmission components, achieving speed reduction and torque increase at a speed ratio of 2.5 to 5. Alternatively, two stages of the planetary reduction mechanism can be fixed to achieve a direct drive with a speed ratio of 1. However, this approach is complex and difficult to implement.

[0003] Furthermore, in electric drive axles with differentials, the space occupied by the differential is relatively large, thus limiting the space available for the reducer and electric motor. Therefore, a reducer with better space utilization is required. The three-stage reduction gears and planetary gear reducers used in electric trucks to date are difficult to implement in a compact design. In addition, while numerous electric drive axle designs for passenger cars are known, they differ significantly from those for electric trucks in many aspects. For example, electric trucks have balanced suspensions and leaf springs in their chassis, making it largely impossible to directly adapt passenger car electric drive axles for electric trucks. Summary of the Invention

[0004] Based on the above background technology, the technical problem to be solved by this utility model is to provide an electric drive bridge with high efficiency, short transmission path and compact structure.

[0005] According to a first aspect of the present invention, an electric drive axle for an electric truck is provided, comprising a main drive motor, a reducer assembly, and a differential assembly. The reducer assembly includes a first-stage reduction stage, a first-gear transmission mechanism, a second-gear transmission mechanism, a third-gear transmission mechanism, a first shifting mechanism, and a second shifting mechanism. The first-stage reduction stage consists of a meshing first-stage reduction drive gear and a first-stage reduction driven gear, with the first-stage reduction drive gear fixedly supported on the motor shaft. The first-gear transmission mechanism consists of a planetary gear reducer, a first drive gear, and a first driven gear. The second-gear transmission mechanism consists of a planetary carrier of the planetary gear reducer, a first drive gear, and a first driven gear. The third-gear transmission mechanism consists of a second drive gear and a second driven gear. The torque of the main drive motor is transmitted to the differential assembly via the first-stage reduction stage through the first-gear transmission mechanism, the second-gear transmission mechanism, or the third-gear transmission mechanism.

[0006] According to this invention, transmission is achieved through a planetary gear reducer in first gear operation, while the transmission ratio is not generated through a planetary gear reducer in second and third gear operation. This allows for a high transmission ratio in first gear operation, where the input power is distributed across multiple planetary gears, achieving efficient deceleration and stable power transmission. Furthermore, the transmission path in second and third gear operation is shortened, improving transmission efficiency. Simultaneously, the first and second gear transmission mechanisms share a common first driving gear and first driven gear, resulting in a simpler and more compact overall structure for the electric drive axle. Moreover, by reducing the number of reduction stages, a low-speed flat-wire motor can be used, leveraging its high efficiency at low to medium speeds and fully utilizing its energy-saving performance.

[0007] According to a preferred design, in first gear operation, the first shifting mechanism connects the driven gear of the first-stage reduction gear to the sun gear of the planetary gear reducer in a torque-transmitting manner. The second shifting mechanism fixes the first driven gear to the input hub of the differential assembly. The planetary carrier has an input end and an output end. In second gear operation, the first shifting mechanism connects the driven gear of the first-stage reduction gear to the input end of the planetary carrier in a torque-transmitting manner, wherein the first driving gear is coaxially fixedly connected to the output end of the planetary carrier. The second shifting mechanism fixes the first driven gear to the input hub of the differential assembly. This design achieves the power transmission paths for first and second gears, ensuring power transmission for the vehicle during low-to-medium speed operation.

[0008] According to a preferred design, in third gear operation, the second shifting mechanism disconnects from the first driven gear and fixes the second driven gear to the input gear hub of the differential assembly, thereby achieving efficient power transmission of the vehicle at high speed with a shorter transmission path.

[0009] According to a preferred design, the sun gear of the planetary gear reducer has an input end, and the input end has an intermediate gear coaxially and fixedly connected to the sun gear. The first shifting mechanism consists of a first gear sleeve, a first gear hub mounted on the first-stage driven gear, and a second gear hub mounted at the input end of the planetary carrier. In first gear operation, the first gear sleeve coaxially and fixedly connects the first gear hub to the intermediate gear. In second gear operation, the first gear sleeve fixes the first gear hub to the second gear hub. The second shifting mechanism consists of a second gear sleeve, a third gear hub mounted on the first driven gear, and a fourth gear hub mounted on the second driven gear. In first and second gear operation, the second gear sleeve fixes the third gear hub to the input gear hub of the differential assembly. In third gear operation, the second gear sleeve fixes the fourth gear hub to the input gear hub of the differential assembly. This ensures a simple and reliable connection between the first and second shifting mechanisms and their corresponding components.

[0010] According to a preferred design, the input hub of the differential assembly is fixedly supported on the input shaft of the differential assembly. The input shaft is configured as a hollow shaft and is connected to the differential housing to transmit torque. The hollow shaft is coaxially supported with the axle. The differential housing is connected to the axle to transmit torque via a bevel gear transmission structure. The first driven gear and the second driven gear are supported on the input shaft of the differential assembly by bearings. The input hub of the differential assembly is arranged between the first driven gear and the second driven gear. This coaxial arrangement structure achieves a more compact structure for the electric drive axle and provides favorable conditions for the connection of the second shifting mechanism and corresponding components.

[0011] According to a preferred design, the second shifting mechanism disconnects from the first driven gear and the second driven gear, thereby disconnecting the power connection between the differential assembly and the reducer assembly. This allows the vehicle to coast in neutral in a simple way, and reduces the rotational inertia of the motor and transmission system when in neutral, thus achieving energy saving.

[0012] According to a preferred design, a power take-off (PTO) is provided, which can be connected to a first driven gear or a second driven gear via a clutch mechanism, thereby enabling flexible power input to the PTO according to power requirements.

[0013] According to a preferred design, the first-stage reduction driven gear and the second driving gear are coaxially fixedly connected, and the second driven gear meshes with the second driving gear. This structure enables the second driven gear to output power when the vehicle is in first gear, second gear, and neutral gear, thereby enabling the second driven gear to provide power input to devices such as the power take-off when the vehicle is in first gear, second gear, and neutral gear.

[0014] According to a preferred design, the second drive gear is coaxially and fixedly connected to the first drive gear. This design reduces the speed ratio differences between gears, improving driving comfort. Furthermore, it provides an additional power mode, allowing for flexible selection of whether to engage the planetary gear reducer in the transmission path during third-gear operation, depending on the operating conditions.

[0015] According to a preferred design, the electric drive axle further includes at least one auxiliary drive motor, which is coupled to a primary reduction gear via an auxiliary drive first-stage reduction drive gear. A power disengagement device is provided between the auxiliary drive motor and the primary reduction drive gear, thereby enabling the auxiliary drive motor to be engaged with the electric drive axle when high power output is required, such as during vehicle starting or hill climbing, while disengaging from the electric drive axle during normal vehicle operation to reduce energy consumption. The auxiliary drive motor can also be a low-speed flat-wire motor.

[0016] According to a preferred design, the main drive motor, auxiliary drive motor, reducer assembly, and differential assembly are arranged in a common housing. This makes the electric drive axle more compact and is particularly beneficial for the design of the lubrication system, thereby lubricating the components inside the entire housing.

[0017] According to a second aspect of this utility model, an electric drive axle is provided for use in an electric truck. The electric drive axle includes a main drive motor, a reducer assembly, and a differential assembly. The reducer assembly includes a first-stage reduction stage, a first-gear transmission mechanism, a second-gear transmission mechanism, a third-gear transmission mechanism, a first shifting mechanism, and a second shifting mechanism. The first-stage reduction stage consists of a meshing first-stage reduction drive gear and a first-stage reduction driven gear. The first-stage reduction drive gear is fixedly supported on the motor shaft. The first-gear transmission mechanism consists of a planetary gear reducer, a third drive gear, and a third driven gear. The second-gear transmission mechanism consists of a fourth drive gear and a fourth driven gear. The third-gear transmission mechanism consists of a planetary carrier of a planetary gear reducer, a third drive gear, and a third driven gear. The torque of the main drive motor is transmitted to the differential assembly via the first-stage reduction stage through the first-gear transmission mechanism, the second-gear transmission mechanism, or the third-gear transmission mechanism. The transmission ratio between the fourth drive gear and the fourth driven gear is greater than the transmission ratio between the third drive gear and the third driven gear.

[0018] This design can appropriately reduce the speed ratio difference between first and second gear, and appropriately increase the speed ratio difference between second and third gear, thereby facilitating the balance of the speed ratios of the three gears and improving driving stability and comfort. Attached Figure Description

[0019] The above-mentioned features and advantages of this utility model, as well as the ways in which they are implemented, are described in detail below with reference to specific embodiments and the accompanying drawings. However, this utility model is not limited to the features of the specific embodiments. (See attached drawings.)

[0020] In the picture:

[0021] Figure 1 shows an electric drive bridge according to the first aspect of this utility model.

[0022] Figure 2 illustrates the power transmission path of the electric drive axle during first-gear operation of a vehicle, using the electric drive axle of the first aspect of this utility model as an example.

[0023] Figure 3 illustrates the power transmission path of the electric drive axle during second-gear operation of a vehicle, using the electric drive axle of the first aspect of this utility model as an example.

[0024] Figure 4 illustrates the power transmission path of the electric drive axle during vehicle operation in third gear, using the electric drive axle of the first aspect of this utility model as an example.

[0025] Figure 5 illustrates the power transmission path of the electric drive axle when the vehicle is running in neutral, using the electric drive axle of the first aspect of this utility model as an example.

[0026] Figure 6 schematically illustrates another embodiment of the three-speed transmission mechanism, taking the electric drive bridge of the first aspect of this utility model as an example.

[0027] Figure 7 shows an electric drive bridge according to a second aspect of the present invention. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. Based on the described embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0029] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar words used in this patent application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "front," "back," "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; these relative positional relationships may change accordingly when the absolute position of the described object changes.

[0030] The accompanying drawings in this utility model are not drawn to scale. They are only considered to be part of this utility model when the dimensions and positional relationships are clearly explained. The specific dimensions and quantities of each structure can be determined according to actual needs.

[0031] Referring to FIG1, a first aspect of the present invention is generally described, wherein the electric drive axle comprises: a main drive motor 1; a first-stage reduction drive gear 2; an auxiliary drive motor 3; a power disengagement device 4; an auxiliary drive first-stage reduction drive gear 5; a first-stage reduction driven gear 6; a second drive gear 7; a second driven gear 8; a second shifting mechanism 9; a right half-shaft 10; a power take-off transmission gear 11; a power take-off coupling device 12; a first driven gear 13; a differential assembly 14; a left half-shaft 15; a first shifting mechanism 16; a planetary carrier 17; a first drive gear 18; planetary gears 19; a ring gear 20; and an input hub 21 of the differential assembly.

[0032] Referring to Figure 1, the electric drive axle includes a main drive motor, a reducer assembly, and a differential assembly. The reducer assembly includes a first-stage reduction stage, a first-gear transmission mechanism, a second-gear transmission mechanism, a third-gear transmission mechanism, a first shifting mechanism, and a second shifting mechanism. The first-stage reduction stage consists of a meshing first-stage reduction drive gear and a first-stage reduction driven gear. The first-stage reduction drive gear is fixedly supported on the motor shaft. The first-gear transmission mechanism consists of a planetary gear reducer, a first drive gear, and a first driven gear; the second-gear transmission mechanism consists of a planetary carrier, a first drive gear, and a first driven gear; and the third-gear transmission mechanism consists of a second drive gear and a second driven gear. Torque is transmitted to the differential assembly via the first-stage reduction stage through the first-gear transmission mechanism, the second-gear transmission mechanism, or the third-gear transmission mechanism.

[0033] In the described embodiment, the electric drive axle also includes at least one auxiliary drive motor, which is coupled to a primary reduction gear via an auxiliary drive first-stage reduction gear. A power disengagement device is provided between the output shaft of the auxiliary drive motor and the shaft of the primary reduction gear, thereby enabling the auxiliary drive motor to be engaged with the electric drive axle when high power output is required, such as during vehicle starting or hill climbing, and disengaged from the electric drive axle during normal vehicle operation, in which case the auxiliary drive motor is preferably in an off state. The auxiliary drive motor can also be a low-speed flat-wire motor. The primary reduction gear is fixedly supported on the shaft; alternatively, the primary reduction gear is manufactured integrally with the shaft.

[0034] The first gear transmission mechanism of the reducer assembly consists of a planetary gear reducer, a first driving gear, and a first driven gear. In the embodiment, the sun gear of the planetary gear reducer and the intermediate gear are fixedly supported on a common shaft to transmit torque. The sun gear can also be constructed integrally with the intermediate gear and the common shaft. In an alternative embodiment, the intermediate gear can also be designed as a gear shaft.

[0035] The first shifting mechanism connects the driven gear of the first-stage reduction gear with the intermediate gear in a torque-transmitting manner, thereby transmitting torque to the planetary gear reducer via the intermediate gear. In the embodiment, the first shifting mechanism consists of a first gear sleeve, a first gear hub disposed on the driven gear of the first-stage reduction gear, and a second gear hub disposed at the input end of the planetary carrier. In first gear operation, the first gear sleeve coaxially and fixedly connects the first gear hub with the intermediate gear, thereby transmitting torque to the planetary gear reducer via the sun gear through the intermediate gear. In second gear operation, the first gear sleeve fixes the first gear hub and the second gear hub together, thereby transmitting torque to the planetary carrier. In the embodiment, the second shifting mechanism consists of a second gear sleeve, a third gear hub disposed on the first driven gear, and a fourth gear hub disposed on the second driven gear. In first and second gear operation, the third gear hub is fixedly connected to the input gear hub of the differential assembly through the second gear sleeve, thereby transmitting torque to the differential assembly via the first driving gear and the first driven gear. In third gear operation, the fourth gear hub is fixedly connected to the input gear hub of the differential assembly through the second gear sleeve, thereby transmitting torque to the differential assembly via the second driven gear.

[0036] In the embodiment described, a power take-off (PTO) is also provided, which is used to use the power of the electric motor to drive other energy-consuming devices in the truck, such as those used to drive the mixing drum in the case of a concrete mixer truck. In this embodiment, the input end of the PTO can be coupled to a PTO drive gear, for example, via a power disengagement device. In this embodiment, the PTO drive gear is coupled to a first driven gear. In another preferred embodiment, an additional PTO drive gear meshing with a second driven gear is also provided. The PTO can be selectively coupled to either the first or second driven gear via the PTO coupling device, depending on demand and operating conditions. Alternatively, two PTOs are provided, each coupled to a first driven gear and a second driven gear, respectively.

[0037] In the described embodiment, the input hub of the differential assembly is fixedly supported on the input shaft of the differential assembly. The input shaft is a hollow shaft and is connected to the differential housing for torque transmission. The hollow shaft is coaxially supported outside the axle. The differential housing is connected to the axle for torque transmission via a bevel gear drive structure. The first driven gear and the second driven gear are supported on the input shaft of the differential assembly by bearings. The input hub of the differential assembly is arranged between the first driven gear and the second driven gear. When the vehicle is in gear, torque is transmitted through the input hub of the differential assembly to the bevel gear drive structure in the differential via the differential housing, thereby driving the axle to rotate.

[0038] Figure 2 schematically illustrates the power transmission path of the electric drive axle in first gear operation using bold lines. In first gear operation, the first gear sleeve moves to coaxially connect the first gear hub on the first-stage reduction driven gear with the intermediate gear for torque transmission. The second gear sleeve moves to coaxially connect the third gear hub on the first driven gear with the input gear hub of the differential assembly for torque transmission. At this time, first gear is engaged through the first and second shift mechanisms, thereby transmitting power from the main drive motor and, if necessary, the auxiliary drive motor to the wheels along the transmission path: first-stage reduction drive gear, first-stage reduction driven gear, first gear hub, first gear sleeve, intermediate gear, sun gear, planet gears, planet carrier, first drive gear, first driven gear, third gear hub, second gear sleeve, input gear hub of the differential assembly, input shaft, differential, and axle.

[0039] Figure 3 schematically illustrates the power transmission path of the electric drive axle in second gear operation using bold lines. In second gear, the first gear sleeve moves to coaxially connect the first gear hub with the second gear hub located at the input end of the planetary carrier for torque transmission. If necessary, the second gear sleeve moves to coaxially connect the third gear hub located at the first driven gear with the input gear hub of the differential assembly for torque transmission. This engages second gear via the first and second shift mechanisms. At this point, power is transmitted to the wheels along the transmission path: first-stage reduction drive gear, first-stage reduction driven gear, first gear hub, first gear sleeve, second gear hub, planetary carrier, first drive gear, first driven gear, third gear hub, second gear sleeve, input gear hub of the differential assembly, input shaft, differential, and axle. In second gear operation, the planetary carrier, as a whole, transmits torque without generating a gear ratio.

[0040] Figure 4 schematically illustrates the power transmission path of the electric drive axle in third gear operation using bold lines. In third gear operation, the first gear sleeve moves, disconnecting its connection with the first gear hub, thereby stopping the operation of the first and second gear transmission mechanisms to save energy. Simultaneously, the second gear sleeve moves, coaxially connecting the fourth gear hub with the input gear hub of the differential assembly for torque transmission, thus engaging third gear via the second shift mechanism. At this point, power from the main drive motor and, if necessary, the auxiliary drive motor is transmitted to the wheels along the transmission path: first-stage reduction drive gear, first-stage reduction driven gear, second drive gear, second driven gear, fourth gear hub, second gear sleeve, input gear hub of the differential assembly, input shaft, differential, and axle. The power take-off (PTO) can then obtain power through the second driven gear. Alternatively, in third gear operation, the first gear sleeve remains connected to the second gear hub or intermediate gear, thereby maintaining the operation of the first or second gear transmission mechanism, allowing the PTO to also obtain power from the first driven gear in third gear operation.

[0041] Figure 5 schematically illustrates the power transmission path of the electric drive axle during neutral operation. When in neutral, the second gear sleeve moves to disconnect the input hub of the differential assembly from the first driven gear and the second driven gear. At this time, no power is transmitted to the input shaft of the differential assembly, allowing the vehicle to coast in neutral. During this period, the torque of the main drive motor is transmitted to the second driven gear via the first-stage reduction drive gear, the first-stage reduction driven gear, and the second drive gear. The power take-off (PTO) can always obtain power from the second driven gear. Similarly, during neutral operation, the first gear sleeve can maintain connection with the second hub or the intermediate gear, allowing the torque of the main drive motor to be transmitted to the first driven gear, thus enabling the PTO to also obtain power from the first driven gear.

[0042] Figure 6 schematically illustrates another embodiment of the three-speed transmission mechanism, in which the second driving gear 7' is coaxially connected to the first driving gear 18 to transmit torque, so that the torque output by the planet carrier of the planetary gear reducer can be transmitted to the second driving gear 7'. In third-speed operation, the planetary gear reducer may not be connected to the transmission path, but instead, the planet carrier can be used as the transmission component, similar to second-speed operation. Specifically, the first gear hub and the second gear hub are connected by a first gear sleeve, thereby transmitting torque to the planet carrier, and then to the second driving gear 7' via the planet carrier. Alternatively, in third-speed operation, the planetary gear reducer can be connected to the transmission path. Specifically, the first gear hub and the intermediate gear are coaxially fixedly connected by a first gear sleeve, thereby transmitting torque to the planetary gear reducer via the sun gear through the intermediate gear, and then outputting it to the second driving gear 7' via the planet carrier. In this embodiment, the power take-off (PTO) can obtain power through the second driven gear 8' in third-speed operation.

[0043] Referring to FIG7, a second aspect of the present invention is described in a generalized manner. In this embodiment, the third driving gear 31 is coaxially fixedly connected to the output end of the planetary carrier and meshes with the third driven gear. The fourth driving gear 41 is coaxially fixedly connected to the first-stage reduction driven gear and meshes with the fourth driven gear 42. The transmission ratio between the fourth driving gear and the fourth driven gear is greater than the transmission ratio between the third driving gear and the third driven gear.

[0044] In first gear operation, power is transmitted to the wheels along the transmission path of the first-stage reduction drive gear 2, the first-stage reduction driven gear 6, the first shift mechanism 16, the sun gear, planet gears, planet carrier, the third drive gear 31, the third driven gear 32, the third gear hub, the second gear sleeve, the input gear hub of the differential assembly, the input shaft, the differential, and the axle; in second gear operation, power is transmitted to the wheels along the transmission path of the first-stage reduction drive gear 2, the first-stage reduction driven gear 6, the fourth drive gear 41, the fourth driven gear 42, the third gear hub, the second gear sleeve, the input gear hub of the differential assembly, the input shaft, the differential, and the axle. In third gear, the power is transmitted to the wheels via the transmission path of the second shift mechanism 9, the input hub of the differential assembly, the input shaft, the differential, and the axle. This transmission path includes the first-stage reduction drive gear 2, the first-stage reduction driven gear 6, the first shift mechanism 16, the planetary carrier 17, the third drive gear 31, the third driven gear 42, the second shift mechanism 9, and the input hub of the differential assembly, the input shaft, the differential, and the axle. In third gear, the planetary carrier, as a whole, transmits torque without generating a gear ratio.

[0045] In this embodiment, the structure and working principle of the first and second shifting mechanisms correspond to the implementation method of the electric drive bridge in the first aspect of this utility model, and will not be described again here.

[0046] Those skilled in the art should understand that the specific embodiments described above are merely examples and not limitations. Various modifications, combinations, partial combinations, and substitutions can be made to the embodiments of this utility model according to design requirements and other factors, as long as they are within the scope of the appended claims or their equivalents, and thus fall within the scope of the rights to be protected by this utility model.

Claims

1. An electric drive axle for use in an electric truck, the electric drive axle comprising a main drive motor, a reduction gear assembly, and a differential assembly, wherein, The reducer assembly has a first-stage reduction stage, a first-gear transmission mechanism, a second-gear transmission mechanism, a third-gear transmission mechanism, a first shifting mechanism, and a second shifting mechanism. The first-stage reduction stage consists of a first-gear reduction drive gear and a first-gear reduction driven gear that mesh with each other. The first-gear reduction drive gear is fixedly supported on the motor shaft. The first-gear transmission mechanism consists of a planetary gear reducer, a first drive gear, and a first driven gear. The second-gear transmission mechanism consists of a planet carrier of the planetary gear reducer, a first drive gear, and a first driven gear. The third-gear transmission mechanism consists of a second drive gear and a second driven gear. The torque of the main drive motor is transmitted to the differential assembly via the first-stage reduction stage through the first-gear transmission mechanism, the second-gear transmission mechanism, or the third-gear transmission mechanism.

2. The electric drive bridge according to claim 1, characterized in that, In first gear operation, the first shifting mechanism connects the driven gear of the first-stage reduction gear to the sun gear of the planetary gear reducer in a torque-transmitting manner, and the second shifting mechanism fixes the first driven gear to the input hub of the differential assembly. In second gear operation, the first shifting mechanism connects the driven gear of the first-stage reduction gear to the input end of the planetary carrier in a torque-transmitting manner, wherein the first driving gear is fixedly and coaxially fixedly connected to the output end of the planetary carrier, and the second shifting mechanism fixes the first driven gear to the input hub of the differential assembly.

3. The electric drive bridge according to claim 1, characterized in that, In third gear operation, the second shifting mechanism disconnects from the first driven gear and fixes the second driven gear to the input gear hub of the differential assembly.

4. The electric drive bridge according to claim 1, characterized in that, The sun gear of the planetary gear reducer has an input end, and the input end has an intermediate gear fixedly connected to the sun gear coaxially. The first shifting mechanism consists of a first gear sleeve, a first gear hub disposed on the first-stage reduction driven gear, and a second gear hub disposed at the input end of the planetary carrier. In first gear operation, the first gear sleeve fixes the first gear hub to the intermediate gear coaxially. In second gear operation, the first gear sleeve fixes the first gear hub to the second gear hub. The second shifting mechanism consists of a second gear sleeve, a third gear hub disposed on the first driven gear, and a fourth gear hub disposed on the second driven gear. In first and second gear operation, the second gear sleeve fixes the third gear hub to the input gear hub of the differential assembly. In third gear operation, the second gear sleeve fixes the fourth gear hub to the input gear hub of the differential assembly.

5. The electric drive bridge according to claim 1, characterized in that, The input hub of the differential assembly is fixedly supported on the input shaft of the differential assembly. The input shaft is a hollow shaft and is connected to the differential housing to transmit torque. The hollow shaft is supported coaxially with the axle. The differential housing is connected to the axle to transmit torque through a bevel gear transmission structure. The first driven gear and the second driven gear are supported on the input shaft of the differential assembly by bearings. The input hub of the differential assembly is arranged between the first driven gear and the second driven gear.

6. The electric drive bridge according to claim 1, characterized in that, The second shifting mechanism disconnects from the first driven gear and the second driven gear to enable the truck to run in neutral.

7. The electric drive bridge according to claim 1, characterized in that, The first-stage reduction driven gear is coaxially and fixedly connected to the second driving gear, and the second driven gear meshes with the second driving gear.

8. The electric drive bridge according to claim 1, characterized in that, The electric drive bridge also has at least one auxiliary drive motor, which is coupled to the primary reduction drive gear and the primary reduction driven gear through the auxiliary drive first-stage reduction drive gear, wherein a power disengagement device is provided between the auxiliary drive motor and the primary reduction drive gear.

9. An electric drive axle for use in an electric truck, the electric drive axle comprising a main drive motor, a reduction gear assembly, and a differential assembly, wherein, The reducer assembly comprises a first-stage reduction stage, a first-gear transmission mechanism, a second-gear transmission mechanism, a third-gear transmission mechanism, a first shifting mechanism, and a second shifting mechanism. The first-stage reduction stage consists of a meshing first-stage reduction drive gear and a first-stage reduction driven gear, with the first-stage reduction drive gear fixedly supported on the motor shaft. The first-gear transmission mechanism is characterized by comprising a planetary gear reducer, a third drive gear, and a third driven gear; the second-gear transmission mechanism consists of a fourth drive gear and a fourth driven gear; and the third-gear transmission mechanism consists of a planetary carrier of the planetary gear reducer, a third drive gear, and a third driven gear. The torque of the main drive motor is transmitted to the differential assembly via the first-stage reduction stage through either the first-gear transmission mechanism or the second-gear transmission mechanism or the third-gear transmission mechanism. The transmission ratio between the fourth drive gear and the fourth driven gear is greater than the transmission ratio between the third drive gear and the third driven gear.

10. An electric truck, characterized in that, The electric truck has an electric drive axle according to any one of claims 1 to 9.

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