Electric drive axle and electric truck

Abstract

The invention relates to an electric drive axle for an electric truck, comprising a main drive electric motor, a reduction gear assembly and a differential assembly, wherein the reduction gear assembly has a first reduction stage, a one-gear transmission, a two-gear transmission, a three-gear transmission and a first gear shift mechanism, a second gear shift mechanism, wherein the first reduction stage consists of a first reduction drive gear and a first reduction driven gear which are in mesh with each other, the first reduction drive gear is fixedly supported on the motor shaft, wherein the first reduction driven gear is fixedly connected coaxially with a low-gear drive gear and a high-gear drive gear, wherein the torque of the main drive electric motor is transmitted via the first reduction stage to the differential assembly via the one-gear transmission or the two-gear transmission or the three-gear transmission, characterized in that the one-gear transmission consists of a planetary gear reduction, a low-gear drive gear and a low-gear driven gear, the two-gear transmission consists of a low-gear drive gear and a low-gear driven gear, the three-gear transmission consists of a high-gear drive gear and a high-gear driven gear, wherein the planet carrier of the planetary gear reduction is connected in torque-transmitting manner to the differential housing.

Description

Technical Field

[0001] This invention 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 transmission stages and use planetary gear reducers or planetary gear sets with auxiliary gearboxes to achieve 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, shifting through a planetary gear set requires selectively fixing the sun gear and the ring gear, making the shifting scheme structurally complex.

[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 the present invention is to provide an electric drive bridge with high efficiency, short transmission path and simple shifting.

[0005] The electric drive axle comprises 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-stage reduction driven gear is coaxially and fixedly connected to the low-gear drive gear and the high-gear drive 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. According to the present invention, the first-gear transmission mechanism consists of a planetary gear reducer, a low-gear drive gear, and a low-gear driven gear; the second-gear transmission mechanism consists of a low-gear drive gear and a low-gear driven gear; and the third-gear transmission mechanism consists of a high-gear drive gear and a high-gear driven gear. The planet carrier of the planetary gear reducer is connected to the differential housing for torque transmission. The ring gear of the planetary gear reducer is fixedly mounted on the housing of the electric drive axle.

[0006] According to the present invention, transmission is achieved through a planetary gear reducer in first gear operation. In second and third gear operation, the planetary gear reducer is disconnected from the transmission path. This allows for a high transmission ratio in first gear operation, with the input power distributed across multiple planetary gears, achieving efficient deceleration and stable power transmission. Furthermore, since the planetary gear reducer is not connected to the second and third gear transmission paths, the transmission paths in second and third gear operation are shortened, improving transmission efficiency. It also avoids the complex mechanical connections caused by selectively fixing the ring gear and sun gear during gear shifting via the planetary gear reducer, thus improving reliability. In addition, 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, the input hub of the differential assembly is fixedly mounted 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 coaxially supported on the left and right half-shafts of the vehicle, circumferentially outside the half-shafts. The low-gear driven gear and the high-gear driven gear are supported on the input shaft of the differential assembly via bearings. The input hub of the differential assembly is arranged between the low-gear driven gear and the high-gear driven gear. The sun gear of the planetary gear reducer is coaxially arranged with the low-gear driven gear and the high-gear driven gear. This coaxial arrangement allows for a more compact construction of the electric drive axle and provides favorable conditions for the connection of the first shift mechanism, the second shift mechanism, and corresponding components.

[0008] According to a preferred design, the sun gear is circumferentially positioned outside the input shaft of the differential assembly at a distance from it. In other words, the sun gear meshes with the planetary gears without being supported by bearings on the input shaft of the differential assembly; that is, an annular gap exists between the sun gear and the outer periphery of the input shaft. This design saves space and materials, reducing costs. Furthermore, this design facilitates meshing between the sun gear, planetary gears, and ring gear, and reduces gear wear caused by manufacturing tolerances and vibrations during vehicle operation.

[0009] According to a preferred design, in first gear operation, the first shifting mechanism connects the low-gear driven gear to the sun gear of the planetary gear reducer in a torque-transmitting manner. This design achieves the power transmission path for first gear in the vehicle, and the planetary gear reducer enables a high transmission ratio, ensuring power transmission during low-speed operation.

[0010] According to a preferred design, in second gear operation, the first shifting mechanism disconnects the low-gear driven gear from the sun gear and connects the low-gear driven gear to the input gear hub of the differential assembly for torque transmission. In third gear operation, the first shifting mechanism disconnects the low-gear driven gear from the input gear hub of the differential assembly, and the second shifting mechanism fixes the high-gear driven gear to the input gear hub of the differential assembly. This design achieves simple switching between first and second / third gear operation and ensures power transmission in second and third gear operation with a shorter transmission path.

[0011] According to a preferred design, the first shifting mechanism comprises a first gear sleeve, a first gear hub mounted on the low-gear driven gear, and a sun gear hub mounted on the sun gear. In first gear operation, the first gear sleeve coaxially and fixedly connects the first gear hub and the sun gear hub. The second shifting mechanism comprises a second gear sleeve, a second gear hub mounted on the low-gear driven gear, and a third gear hub mounted on the high-gear driven gear. In second gear operation, the second gear sleeve fixes the second gear hub to the input gear hub of the differential assembly. In third gear operation, the second gear sleeve fixes the third gear hub to the input gear hub of the differential assembly. This achieves a simple and reliable connection between the first and second shifting mechanisms and their corresponding components.

[0012] According to a preferred design, when in neutral, the first gear sleeve disconnects the connection between the low-gear driven gear and the sun gear hub, and the second gear sleeve disconnects the connection between the input hub of the differential assembly and the low-gear and high-gear driven gears, thereby disconnecting the power connection between the differential assembly and the reduction gear assembly. This design achieves neutral coasting in a simple way, and by disconnecting the mechanical connection between the differential assembly and the reduction gear assembly, it reduces the rotational inertia of the electric motor and the transmission system, thus achieving energy saving.

[0013] According to a preferred design, the transmission ratio between the first-stage reduction drive gear and the first-stage reduction driven gear is 2.5 to 4.5, preferably 4; the transmission ratio between the low-gear drive gear and the low-gear driven gear is 2 to 4, preferably 3; and the transmission ratio between the high-gear drive gear and the high-gear driven gear is 1.5 to 3, preferably 1.5. The planetary gear reducer as a whole achieves a transmission ratio of 2 to 4, preferably 2.5. Correspondingly, in first gear, the vehicle achieves a speed ratio of 10 to 72 through the reducer assembly, preferably 30; in second gear, a speed ratio of 5 to 20 through the reducer assembly, preferably 12; and in third gear, a speed ratio of 3.75 to 13.5 through the reducer assembly, preferably 6. This improves the driving experience through the reasonable distribution of speed ratios in each gear, and better meets the speed and torque requirements of transportation conditions through the aforementioned speed ratios in the three gears.

[0014] According to a preferred design, a power take-off (PTO) is provided, which can be selectively connected to a low-gear driven gear or a high-gear driven gear through a PTO coupling device, thereby realizing flexible power input to the PTO according to power demand.

[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. The auxiliary drive motor can also be a different type of motor from the main drive motor.

[0016] According to an alternative design, the auxiliary drive motor is coupled to the low-gear driven gear via the first-stage auxiliary drive reduction stage. The first-stage auxiliary drive reduction drive gear, which is fixedly supported on the motor shaft of the auxiliary drive motor, is coupled to the first-stage auxiliary drive reduction driven gear. The first-stage auxiliary drive reduction driven gear can be coupled to the second-stage auxiliary drive reduction drive gear through the auxiliary drive engagement gear hub sleeve. The second-stage auxiliary drive reduction drive gear is coupled to the low-gear driven gear.

[0017] 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. Attached Figure Description

[0018] The above-mentioned features and advantages of the present invention, 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, the present invention is not limited to the features of the specific embodiments. In the accompanying drawings:

[0019] Figure 1 The electric drive bridge according to the invention is schematically shown, in which gear is not engaged.

[0020] Figure 2 The diagram schematically illustrates the power transmission path of the electric drive axle during first gear operation.

[0021] Figure 3 The diagram schematically illustrates the power transmission path of the electric drive axle when the vehicle is in second gear.

[0022] Figure 4 The diagram schematically illustrates the power transmission path of the electric drive axle during vehicle operation in third gear. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention 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 the present invention. Based on the described embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning 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.

[0025] The accompanying drawings in this invention are not drawn to scale. They are only considered to be part of this invention when the dimensions and positional relationships are clearly explained. The specific dimensions and quantity of each structure can be determined according to actual needs.

[0026] Reference Figure 1The present invention is generally described as follows: the electric drive axle comprises: a main drive motor 1; a first-stage reduction drive gear 2; a first-stage reduction driven gear 3; a low-gear drive gear 4; a low-gear driven gear 5; a high-gear drive gear 6; a high-gear driven gear 7; an input gear hub of the differential assembly 8; a first shifting mechanism 9; a second shifting mechanism 10; a sun gear 11; a ring gear 12; planet gears 13; a sun gear hub 14; a planet carrier 15; a differential housing 16; a differential assembly 17; a left half-shaft 18; a right half-shaft 19; a power take-off coupling device 20; a power take-off transmission gear 21; an auxiliary drive motor 22; a power disengagement device 23; and an auxiliary drive first-stage reduction drive gear 24.

[0027] Reference Figure 1 It is known that the electric drive axle has 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 9, and a second shifting mechanism 10. The first-stage reduction stage consists of a meshing first-stage reduction drive gear 2 and a first-stage reduction driven gear 3. The first-stage reduction drive gear is fixedly supported on the motor shaft. The first-stage reduction driven gear 3 is coaxially fixedly connected to the low-gear drive gear 4 and the high-gear drive gear 6. The first-gear transmission mechanism consists of a planetary gear reducer, a low-gear drive gear 4, and a low-gear driven gear 5. The second-gear transmission mechanism also consists of a low-gear drive gear 4 and a low-gear driven gear 5. The third-gear transmission mechanism consists of a high-gear drive gear 6 and a high-gear driven gear 7. The planetary gear reducer, the low-gear driven gear 5, and the high-gear driven gear 7 are coaxially arranged with the right half-shaft 19 of the vehicle, and the planet carrier of the planetary gear reducer is connected to the differential housing 16 to transmit torque. The differential assembly has an input shaft, which is a hollow shaft and is connected to the differential housing in a torque-transmitting manner. The hollow shaft is coaxially supported on the circumferentially outer side of the left and right half-shafts of the vehicle.

[0028] In the described embodiment, the electric drive axle also includes at least one auxiliary drive motor 22, which is coupled to the primary reduction gear 3 via an auxiliary drive primary reduction drive gear 24. A power disengagement device is provided between the output shaft of the auxiliary drive motor and the shaft of the auxiliary drive 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, 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 auxiliary drive primary reduction gear is fixedly supported on the shaft; alternatively, the auxiliary drive primary reduction gear is manufactured integrally with the shaft.

[0029] The first gear transmission mechanism of the reducer assembly consists of a planetary gear reducer, a low-gear drive gear 4, and a low-gear driven gear 5. In the embodiment, the sun gear and the low-gear driven gear can be connected to transmit torque through the first shifting mechanism 9, thereby transmitting torque through the sun gear hub to the planetary gear reducer.

[0030] In the embodiment, the sun gear has a sun gear hub 14, and the low-gear driven gear 5 has a first hub and a second hub. The first shifting mechanism 9 is composed of a first gear sleeve, the sun gear hub 14, the first hub and the second hub of the low-gear driven gear. In first gear operation, the first hub and the sun gear hub are coaxially fixedly connected by the first gear sleeve, so that the torque is transmitted to the planetary gear reducer through the sun gear hub via the sun gear 11, and then output to the differential housing through the planet carrier 15, driving the differential housing to rotate, and transmitting the torque to the left half shaft 18 and the right half shaft 19 through the bevel gear transmission structure connected to the differential housing. In the embodiment, the second shifting mechanism is composed of a second gear sleeve, the input hub 8 of the differential assembly, the second hub of the low-gear driven gear 5 and the third hub of the high-gear driven gear 7. The input hub of the differential assembly is fixedly mounted on the input shaft of the differential assembly. In second gear operation, the first shifting mechanism disconnects the low-gear driven gear 5 from the sun gear 11, and the second shifting mechanism connects the low-gear driven gear 5 to the input hub 8 of the differential assembly in a torque-transmitting manner, thereby transmitting torque to the differential assembly 17 via the low-gear driven gear 5. In third gear operation, the second gear sleeve of the second shifting mechanism 10 disconnects the connection between the low-gear driven gear 5 and the input hub 8 of the differential assembly, and couples the third hub of the high-gear driven gear 7 to the input hub 8 of the differential assembly, thereby transmitting torque to the differential assembly via the high-gear driven gear 7. In second and third gear operation, torque is transmitted to the differential housing through the input shaft of the differential assembly, and then drives the wheels to rotate through the left half-shaft 18 and right half-shaft 19 in the same manner as in first gear operation.

[0031] In this embodiment, 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 PTO coupling device. Figures 1 to 3 In the illustrated embodiment, the power take-off (PTO) drive gear is coupled to the low-gear driven gear. In another preferred embodiment, an additional PTO drive gear meshes with the high-gear driven gear. The PTO can be selectively coupled to either the low-gear or high-gear driven gear according to demand and operating conditions via the PTO coupling device. Alternatively, two PTOs can be provided, each coupled to the low-gear and high-gear driven gears respectively.

[0032] In the described embodiment, the input hub of the differential assembly is fixedly mounted 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 on the outer circumferential side of the axle. The differential housing is connected to the axle for torque transmission via a bevel gear drive structure. The low-gear driven gear and the high-gear 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 low-gear driven gear and the high-gear driven gear. When the vehicle is in gear, torque is transmitted through the differential housing to the bevel gear drive structure in the differential, thereby driving the axle to rotate.

[0033] Figure 2 The power transmission path of the electric drive axle in first gear is schematically illustrated using bold lines. In first gear, the first gear sleeve moves to connect the first gear hub on the low-gear driven gear with the sun gear hub in a torque-transmitting manner. At this time, the vehicle is engaged in first gear via the first shifting mechanism, 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 2, first-stage reduction driven gear 3, low-gear drive gear 4, low-gear driven gear 5, first gear hub, first gear sleeve, sun gear hub 14, sun gear 11, planetary gears 13, planetary carrier 15, differential housing, left half-shaft, and right half-shaft. In first gear, the transmission ratio between the first-stage reduction drive gear and the first-stage reduction driven gear is 2.5 to 4.5, the transmission ratio between the low-gear drive gear and the low-gear driven gear is 2 to 4, and the overall transmission ratio of the planetary gear reducer is 2 to 4. Correspondingly, in first gear, a speed ratio of 10 to 72, preferably 30, is achieved through the first-stage reduction stage and the first gear transmission mechanism.

[0034] Figure 3 The power transmission path of the electric drive axle in second gear is schematically illustrated by bold lines. In second gear, the first gear sleeve moves to disconnect the coupling between the first gear hub and the sun gear hub. The second gear sleeve moves to connect the second gear hub of the low-gear driven gear with the input gear hub of the differential assembly in a torque-transmitting manner, thereby engaging second gear through the first shift mechanism. At this time, 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 2, first-stage reduction driven gear 3, low-gear drive gear 4, low-gear driven gear 5, second gear hub, second gear sleeve, input gear hub of the differential assembly, differential housing, left half-shaft, and right half-shaft. Correspondingly, a speed ratio of 5 to 20, preferably 12, is achieved in second gear through the first-stage reduction stage and the second-gear transmission mechanism.

[0035] Figure 4The power transmission path of the electric drive axle in third gear operation is schematically illustrated by bold lines. In third gear operation, the first gear sleeve moves, disconnecting its connection with the second gear hub of the low-gear driven gear, and the third gear hub of the high-gear driven gear is connected to the input gear hub of the differential assembly to transmit torque, thereby engaging third gear via the second shift mechanism. At this time, power from the main drive motor and, if necessary, the auxiliary drive motor is transmitted to the wheels along the transmission path of the first-stage reduction drive gear 2, the first-stage reduction driven gear 3, the high-gear drive gear 6, the high-gear driven gear 7, the third gear hub, the second gear sleeve, the input gear hub of the differential assembly, the differential housing, the left half-shaft, and the right half-shaft. In third gear operation, the gear ratio between the high-gear drive gear and the high-gear driven gear is 1.5 to 3, preferably 1.5, thereby achieving a speed ratio of 3.75 to 13.5, preferably 6, through the first-stage reduction stage and the third-gear transmission mechanism.

[0036] Figure 1 The diagram also schematically illustrates the power transmission path of the electric drive axle during neutral operation. In neutral, both the first and second gear sleeves are in the disengaged position, thus disconnecting the low-gear driven gear from the sun gear or the input hub of the differential assembly, and the high-gear driven gear from the input hub of the differential assembly. At this time, no power is transmitted to the input shaft of the differential assembly, allowing the vehicle to coast in neutral. The torque of the main drive motor is then transmitted to the low-gear and high-gear driven gears via the first-stage reduction drive gear, the first-stage reduction driven gear, the low-gear drive gear, and the high-gear drive gear. In this embodiment, the power take-off (PTO) can obtain power from the low-gear or high-gear driven gear according to specific operating conditions and needs in first, second, third, and neutral operation.

[0037] 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 the present invention 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 the present invention.

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 single 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 single-gear reduction stage consists of a meshing single-gear drive gear and a single-gear driven gear. The single-gear drive gear is fixedly supported on the motor shaft. The single-gear driven gear is coaxially and fixedly connected to the low-gear drive gear and the high-gear drive gear. The torque of the main drive motor is transmitted to the differential assembly via the single-gear reduction stage through the first-gear transmission mechanism, the second-gear transmission mechanism, or the third-gear transmission mechanism. The first-gear transmission mechanism consists of a planetary gear reducer, a low-gear drive gear, and a low-gear driven gear. The differential assembly consists of a two-speed transmission mechanism comprised of a low-speed drive gear and a low-speed driven gear, and a three-speed transmission mechanism comprised of a high-speed drive gear and a high-speed driven gear. The planetary carrier of the planetary gear reducer is connected to the differential housing for torque transmission. The ring gear of the planetary gear reducer is fixedly mounted on the housing of the electric drive axle. The input shaft of the differential assembly is a hollow shaft and is connected to the differential housing for torque transmission. The low-speed driven gear and the high-speed driven gear are supported on the input shaft of the differential assembly by bearings. The sun gear of the planetary gear reducer is coaxially arranged on the input shaft of the differential assembly with the low-speed driven gear and the high-speed driven gear.

2. The electric drive bridge according to claim 1, characterized in that, An input gear hub of the differential assembly is fixedly provided on the input shaft of the differential assembly, wherein the hollow shaft is coaxially supported on the left and right half shafts of the vehicle in the circumferential direction, and the input gear hub of the differential assembly is arranged between the low-gear driven gear and the high-gear driven gear.

3. The electric drive bridge according to claim 2, characterized in that, The sun gear is circumferentially positioned outside the input shaft of the differential assembly at a distance from the input shaft of the differential assembly.

4. The electric drive bridge according to claim 1, characterized in that, In first gear operation, the first shifting mechanism connects the low-gear driven gear to the sun gear of the planetary gear reducer in a torque-transmitting manner. In second gear operation, the first shifting mechanism disconnects the low-gear driven gear from the sun gear and connects the low-gear driven gear to the input gear hub of the differential assembly in a torque-transmitting manner. In third gear operation, the first shifting mechanism disconnects the low-gear driven gear from the input gear hub of the differential assembly, and the second shifting mechanism fixes the high-gear driven gear to the input gear hub of the differential assembly.

5. The electric drive bridge according to claim 1, characterized in that, The first shifting mechanism consists of a first gear sleeve, a first gear hub mounted on the low-gear driven gear, and a sun gear hub mounted on the sun gear. In first gear operation, the first gear sleeve coaxially and fixedly connects the first gear hub and the sun gear hub. The second shifting mechanism consists of a second gear sleeve, a second gear hub mounted on the low-gear driven gear, and a third gear hub mounted on the high-gear driven gear. In second gear operation, the second gear sleeve fixes the second gear hub to the input gear hub of the differential assembly. In third gear operation, the second gear sleeve fixes the third gear hub to the input gear hub of the differential assembly.

6. The electric drive bridge according to claim 1, characterized in that, In neutral, the first gear sleeve disconnects the connection between the low-gear driven gear and the sun gear hub, and the second gear sleeve disconnects the connection between the input hub of the differential assembly and the low-gear driven gear and the high-gear driven gear, thereby disconnecting the power connection between the differential assembly and the reduction gear assembly.

7. The electric drive bridge according to claim 1, characterized in that, The transmission ratio between the first-stage reduction drive gear and the first-stage reduction driven gear is 2.5 to 4.5, the transmission ratio between the low-gear drive gear and the low-gear driven gear is 2 to 4, and the transmission ratio between the high-gear drive gear and the high-gear driven gear is 1.5 to 3. The planetary gear reducer as a whole achieves a transmission ratio of 2 to 4.

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 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.

9. The electric drive bridge according to claim 8, characterized in that, The main drive motor, auxiliary drive motor, reducer assembly, and differential assembly are arranged in a common housing.

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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