Electric drive axle and electric truck

Abstract

The invention relates to an electric drive axle for an electric truck, the electric drive axle is provided with a main drive motor, a speed reducer assembly and a differential assembly, the speed reducer assembly is provided with a first speed reduction stage, 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-stage speed reduction stage is composed of a first-stage speed reduction driving gear and a first-stage speed reduction driven gear which are meshed with each other, the first-stage speed reduction driving gear is fixedly supported on a motor shaft, and the first-stage speed reduction driven gear is coaxially and fixedly connected with the low-gear driving gear and the high-gear driving gear; torque of the main drive motor is transmitted to the differential mechanism assembly through the first-gear transmission mechanism or the second-gear transmission mechanism or the third-gear transmission mechanism via the first-stage speed reduction stage, and is characterized in that the first-gear transmission mechanism is composed of a planetary gear speed reducer, a low-gear driving gear and a low-gear driven gear; the second-gear transmission mechanism is composed of a low-gear driving gear and a low-gear driven gear, the third-gear transmission mechanism is composed of a high-gear driving gear and a high-gear driven gear, and a planet carrier of the planetary gear reducer is connected with the differential mechanism shell in a torque transmission mode.

Description

Technical Field

[0001] The present invention relates to an electric drive axle and an electric truck having such an electric drive axle. Background Art

[0002] In the electric drive architectures mainly used so far in electric trucks, motors with a speed above 12,000 RPM are usually adopted. For motors in this speed range, a transmission mechanism with three or more stages is usually required, and planetary gear train technology is used for speed reduction, or a planetary gear train auxiliary box structure is adopted to achieve gear shifting. Among them, the ring gear is fixed, the sun gear is used as the driving transmission component, and the planetary gear is used as the driven transmission component to achieve speed reduction and torque increase with a speed ratio of 2.5 to 5, or two stages of components of the planetary reduction mechanism are fixed to achieve direct drive with a speed ratio of 1. However, shifting gears through the planetary gear train requires selectively fixing the sun gear and the ring gear, making the structure of the shifting gear scheme complex.

[0003] In addition, in an electric drive axle with a differential, since the differential occupies a large space, the space for the reducer and the motor is more limited, so a reducer with better space utilization is required. The three-stage reduction mechanism and the planetary gear train reduction device used in electric trucks so far are difficult to achieve a compact structure. In addition, a large number of electric drive axle designs for passenger cars are known in this regard, but the electric drive axles of passenger cars are significantly different from those of electric trucks in many aspects. For example, a balance suspension and leaf springs are provided on the chassis of an electric truck. Therefore, the electric drive axles of passenger cars basically cannot be directly applied to electric trucks. Summary of the Invention

[0004] Based on the above background art, the technical problem to be solved by the present invention is to provide an electric drive axle with high efficiency, short transmission path and simple gear shifting.

[0005] The electric drive axle has a main drive motor, a reducer assembly and a differential assembly. Among them, 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. Among them, the first-stage reduction stage is composed of a first-stage reduction driving gear and a first-stage reduction driven gear that mesh with each other. The first-stage reduction driving gear is fixedly supported on the motor shaft. Among them, the first-stage reduction driven gear is fixedly connected coaxially with the low-gear driving gear and the high-gear driving gear. Among them, the torque of the main drive motor is transmitted to the differential assembly through the first-stage reduction stage by the first-gear transmission mechanism or the second-gear transmission mechanism or the third-gear transmission mechanism. According to the present invention, the first-gear transmission mechanism is composed of a planetary gear reducer, a low-gear driving gear and a low-gear driven gear. The second-gear transmission mechanism is composed of the low-gear driving gear and the low-gear driven gear. The third-gear transmission mechanism is composed of the high-gear driving gear and the high-gear driven gear. Among them, the planet carrier of the planetary gear reducer is connected to the differential housing for torque transmission. Among them, the ring gear of the planetary gear reducer is fixedly arranged on the housing of the electric drive axle.

[0006] According to the present invention, the transmission is realized by the planetary gear reducer during the first-gear operation. During the second-gear and third-gear operations, the planetary gear reducer is disconnected from the transmission path. On the one hand, a high transmission ratio is achieved by the planetary gear reducer during the first-gear operation, and the input power is dispersed to multiple planet gears by means of the planetary gear reducer, realizing efficient speed reduction and stable power transmission. On the other hand, since the planetary gear reducer is not connected to the transmission paths of the second gear and the third gear, the transmission paths of the second-gear and third-gear operations are shortened, improving the transmission efficiency and avoiding the complex mechanical connections generated by selectively fixing the ring gear and the sun gear when shifting gears through the planetary gear reducer, thus improving the reliability. In addition, in the case of reducing the number of reduction stages, a flat wire motor with a low rotational speed can be used, thereby giving full play to the advantage of the flat wire motor having a higher efficiency at medium and low rotational speeds and fully exerting the energy-saving performance of the flat wire motor.

[0007] According to a preferred design, the input hub of the differential assembly is fixedly arranged on the input shaft of the differential assembly. The input shaft is arranged as a hollow shaft and is torque-transmittingly connected to the differential housing. The hollow shaft is coaxially supported with the left half shaft and the right half shaft of the vehicle on the circumferential outer sides of the left half shaft and the right half shaft. Among them, 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. The sun gear of the planetary gear reducer is coaxially arranged with the low-gear driven gear and the high-gear driven gear. Through this coaxial arrangement structure, a more compact structure of the electric drive axle is realized, and favorable conditions are provided for the connection of the first shifting mechanism, the second shifting mechanism and the corresponding components.

[0008] According to a preferred design, the sun gear is circumferentially arranged at an interval from the input shaft of the differential assembly on the outer side of the input shaft of the differential assembly. In other words, the sun gear meshes with the planet gear without being supported on the input shaft of the differential assembly by a bearing, that is, there is an annular gap between the outer peripheral side of the sun gear and the input shaft of the differential assembly. Through this design structure, space and materials are saved, and the cost is reduced. In addition, this design structure is more conducive to the meshing between the sun gear, the planet gear and the ring gear, and reduces the gear wear caused by manufacturing tolerances and vibrations during vehicle operation.

[0009] According to a preferred design, during the first-gear operation, the first shifting mechanism torque-transmittingly connects the low-gear driven gear to the sun gear of the planetary gear reducer. Through the above design, the power transmission path of the first gear of the vehicle is realized, and a high transmission ratio is achieved by the planetary gear reducer, ensuring the power transmission of the vehicle during low-speed operation.

[0010] According to a preferred design, during second gear operation, the first shifting mechanism disconnects the low gear driven gear from the sun gear and torque-transmittingly connects the low gear driven gear to the input hub of the differential assembly. During third gear operation, the first shifting mechanism disconnects the low gear driven gear from the input hub of the differential assembly, and the second shifting mechanism fixedly connects the high gear driven gear to the input hub of the differential assembly. With this design, the shift between first gear operation and second and third gear operations is achieved in a simple manner, and the power transmission of the vehicle during second and third gear operations is ensured with a short transmission path.

[0011] According to a preferred design, the first shifting mechanism consists of a first gear sleeve, a first hub provided on the low gear driven gear, and a sun gear hub provided on the sun gear. During first gear operation, the first gear sleeve coaxially and fixedly connects the first hub and the sun gear hub. The second shifting mechanism consists of a second gear sleeve, a second hub provided on the low gear driven gear, and a third hub provided on the high gear driven gear. During second gear operation, the second gear sleeve fixedly connects the second hub to the input hub of the differential assembly. During third gear operation, the second gear sleeve fixedly connects the third hub to the input hub of the differential assembly. In this way, the connection between the first shifting mechanism, the second shifting mechanism and the corresponding components is achieved in a simple and reliable manner.

[0012] According to a preferred design, during neutral operation, 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. With this design, the neutral coasting of the vehicle is achieved in a simple manner, and the rotational inertia of the motor and the powertrain is reduced by disconnecting the mechanical connection between the differential assembly and the reduction gear assembly, achieving the purpose of energy conservation.

[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; 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, when the vehicle is running in the first gear, a speed ratio of 10 to 72 is achieved through the reducer assembly, preferably 30; when running in the second gear, a speed ratio of 5 to 20 is achieved through the reducer assembly, preferably 12; when running in the third gear, a speed ratio of 3.75 to 13.5 is achieved through the reducer assembly, preferably 6. Thus, on the one hand, the driving experience is improved by the reasonable distribution of the speed ratios of each gear, and on the other hand, the requirements of the transportation working conditions in terms of speed and torque are better met through the speed ratios of the three gears.

[0014] According to a preferred design, a power take-off is provided, and the power take-off can be selectively connected to the low-gear driven gear or the high-gear driven gear through a power take-off coupling device, thereby enabling flexible power input to the power take-off according to power requirements.

[0015] According to a preferred design, the electric drive axle further has at least one auxiliary drive motor, which is coupled to the first-stage reduction driven gear through an auxiliary drive first-stage reduction drive gear. A power disengagement device is provided between the auxiliary drive motor and the auxiliary drive first-stage reduction drive gear, so that the auxiliary drive motor can be connected to the electric drive axle when high power output is required, such as when the vehicle starts or climbs, and the auxiliary drive motor can be disengaged from the electric drive axle during normal vehicle operation to reduce energy consumption. The auxiliary drive motor can also be a flat wire motor with a low speed. The auxiliary drive motor can also be a motor of a different type from the main drive motor.

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

[0017] According to a preferred design, the main drive motor, the auxiliary drive motor, the reducer assembly and the differential assembly are arranged in a common housing. This makes the structure of the electric drive axle more compact and is especially beneficial to the design of the lubrication system, thereby lubricating the components inside the entire housing. Description of the Drawings

[0018] The above features and advantages of the present invention and the ways to achieve them will be elaborated in detail below in combination with specific embodiments and with reference to the accompanying drawings. However, the present invention is not limited to the features of the specific embodiments. In the drawings:

[0019] Figure 1 Schematically shows an electric drive axle according to the present invention, with no gear engaged at this time.

[0020] Figure 2 Schematically shows the power transmission path of the electric drive axle when the vehicle is running in first gear.

[0021] Figure 3 Schematically shows the power transmission path of the electric drive axle when the vehicle is running in second gear.

[0022] Figure 4 Schematically shows the power transmission path of the electric drive axle when the vehicle is running in third gear Detailed Description of the Invention

[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 in combination with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0024] Unless otherwise defined, the technical terms or scientific terms used herein shall have the ordinary meanings understood by those of ordinary skill in the art to which the present invention pertains. The "first", "second", and similar terms used in the specification and claims of this patent application of the present invention do not denote any order, quantity, or importance, but are only used to distinguish different components. The terms such as "comprising" or "including" mean that the elements or items appearing before this word cover the elements or items listed after this word and their equivalents, without excluding other elements or items. The terms such as "front", "rear", "upper", "lower", "left", "right", etc. are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0025] The drawings in the present invention are not strictly drawn to actual scale and are regarded as the regulations of the present invention only when the size and positional relationships are clearly stated. The specific sizes and quantities of each structure can be determined according to actual needs.

[0026] Refer to Figure 1Generally describing the present invention, the electric drive axle has: 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 hub 8 of the differential assembly; a first shifting mechanism 9; a second shifting mechanism 10; a sun gear 11; a ring gear 12; a planet gear 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 drive gear 21; an auxiliary drive motor 22; a power disengagement device 23, and an auxiliary drive first-stage reduction drive gear 24.

[0027] Referring to Figure 1 As can be seen, the electric drive axle has a main drive motor, a reduction gear assembly and a differential assembly. Among them, the reduction gear 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 9 and a second shifting mechanism 10. Among them, the first-stage reduction stage is composed of a first-stage reduction drive gear 2 and a first-stage reduction driven gear 3 that mesh with each other. The first-stage reduction drive gear is fixedly supported on the motor shaft. Among them, the first-stage reduction driven gear 3 is fixedly connected coaxially with the low-gear drive gear 4 and the high-gear drive gear 6. The first-gear transmission mechanism is composed of a planetary gear reducer, a low-gear drive gear 4 and a low-gear driven gear 5. The second-gear transmission mechanism is composed of a low-gear drive gear 4 and a low-gear driven gear 5. And the third-gear transmission mechanism is composed of a high-gear drive gear 6 and a high-gear driven gear 7. Among them, the planetary gear reducer, the low-gear driven gear 5 and the high-gear driven gear 7 are arranged coaxially with the right half shaft 19 of the vehicle. And the planet carrier of the planetary gear reducer is torque-transmittingly connected to the differential housing 16. The differential assembly has an input shaft, which is arranged as a hollow shaft and is torque-transmittingly connected to the differential housing. The hollow shaft is coaxially supported on the circumferential outer sides of the left half shaft and the right half shaft of the vehicle.

[0028] In the said embodiment, the electric drive axle further has at least one auxiliary drive motor 22, which can be coupled to the first-stage reduction driven gear 3 through the auxiliary drive first-stage reduction drive gear 24. Among them, a power disengagement device is arranged between the output shaft of the auxiliary drive motor and the shaft of the auxiliary drive first-stage reduction drive gear. Thus, the auxiliary drive motor can be connected to the electric drive axle when high power output is required, such as when the vehicle starts or climbs a slope, and the auxiliary drive motor can be disengaged from the electric drive axle during normal vehicle operation. At this time, 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 first-stage reduction gear is fixedly supported on the shaft. Alternatively, the auxiliary drive first-stage reduction gear is integrally manufactured with the shaft.

[0029] The first-gear transmission mechanism of the reducer assembly consists of a planetary gear reducer, a low-gear driving gear 4, and a low-gear driven gear 5. In the said embodiment, the sun gear can be torque-transmittingly connected to the low-gear driven gear through the first shifting mechanism 9, so that the torque is transmitted to the planetary gear reducer via the sun gear hub and the sun gear.

[0030] In the said 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. Among them, the first shifting mechanism 9 consists of a first gear sleeve, the sun gear hub 14, the first hub and the second hub of the low-gear driven gear. During the first-gear operation, the first hub is coaxially and fixedly connected to the sun gear hub through the first gear sleeve, so that the torque is transmitted to the planetary gear reducer via the sun gear hub and the sun gear 11, and then output to the differential housing through the planet carrier 15 to drive the differential housing to rotate, and is transmitted 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 said embodiment, the second shifting mechanism consists 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 arranged on the input shaft of the differential assembly. During the second-gear operation, the first shifting mechanism disconnects the coupling between the low-gear driven gear 5 and the sun gear 11, and the second shifting mechanism torque-transmittingly connects the low-gear driven gear 5 to the input hub 8 of the differential assembly, so that the torque is transmitted to the differential assembly 17 via the low-gear driven gear 5; During the 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, so that the torque is transmitted to the differential assembly via the high-gear driven gear 7. During the second-gear and third-gear operations, the 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 the right half shaft 19 in the same way as the first-gear operation.

[0031] In the said embodiment, a power take-off is also provided, which is used to use the power of the motor to drive other energy-consuming devices in the truck. For example, when the truck is designed as a concrete mixer truck, the energy-consuming device is used to drive the mixing drum. In the said embodiment, the input end of the power take-off can be coupled to the power take-off drive gear through the power take-off coupling device. In Figures 1 to 3 the shown embodiment, the power take-off drive gear is coupled to the low-gear driven gear. In another preferred embodiment, there is also an additional power take-off drive gear meshing with the high-gear driven gear. The power take-off can be selectively coupled to the low-gear driven gear or the high-gear driven gear according to the requirements and operating conditions through the power take-off coupling device. Alternatively, two power take-offs can be provided, which are respectively coupled to the low-gear driven gear and the high-gear driven gear.

[0032] In the described embodiment, the input gear hub of the differential assembly is fixedly arranged on the input shaft of the differential assembly. The input shaft is arranged as a hollow shaft and is connected to the differential housing for torque transmission. The hollow shaft is coaxially supported on the circumferential outer side of the axle, and the differential housing is connected to the axle for torque transmission through a bevel gear transmission structure. Among them, the low-speed driven gear and the high-speed driven gear are supported on the input shaft of the differential assembly through bearings, and the input gear hub of the differential assembly is arranged between the low-speed driven gear and the high-speed driven gear. When the vehicle is running in gear, torque is transmitted to the bevel gear transmission structure in the differential through the differential housing, thereby driving the axle to rotate.

[0033] Figure 2 The power transmission path of the electric drive axle during the first-gear operation of the vehicle is schematically shown by thick lines. During the first-gear operation, move the first gear sleeve to connect the first gear hub on the low-speed driven gear to the sun gear hub for torque transmission. At this time, shift the vehicle into the first gear through the first shifting mechanism, and thus transmit the power of the main drive motor and, if necessary, the auxiliary drive motor to the wheels along the transmission path of the first-stage reduction drive gear 2, the first-stage reduction driven gear 3, the low-speed drive gear 4, the low-speed driven gear 5, the first gear hub, the first gear sleeve, the sun gear hub 4, the sun gear 11, the planetary gear 13, the planetary carrier 15, the differential housing, the left half axle, and the right half axle. During the first-gear operation, 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-speed drive gear and the low-speed driven gear is 2 to 4, and the total transmission ratio of the planetary gear reducer is 2 to 4. Correspondingly, a speed ratio of 10 to 72, preferably 30, is achieved through the first-stage reduction stage and the first-gear transmission mechanism during the first-gear operation.

[0034] Figure 3 The power transmission path of the electric drive axle during the second-gear operation of the vehicle is schematically shown by thick lines. During the second-gear operation, move the first gear sleeve to disconnect the coupling between the first gear hub and the sun gear hub, and move the second gear sleeve to connect the second gear hub of the low-speed driven gear to the input gear hub of the differential assembly for torque transmission, thereby shifting into the second gear through the first shifting mechanism. At this time, transmit the power of the main drive motor and, if necessary, the auxiliary drive motor to the wheels along the transmission path of the first-stage reduction drive gear 2, the first-stage reduction driven gear 3, the low-speed drive gear 4, the low-speed driven gear 5, the second gear hub, the second gear sleeve, the input gear hub of the differential assembly, the differential housing, the left half axle, and the right half axle. During the second-gear operation, a speed ratio of 5 to 20, preferably 12, is correspondingly achieved through the first-stage reduction stage and the second-gear transmission mechanism.

[0035] Figure 4The power transmission path of the electric drive axle during the third gear operation is schematically shown by thickened lines. During the third gear operation, the first gear sleeve is moved to disconnect 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 torque-transmittingly connected to the input gear hub of the differential assembly, so as to engage the third gear through the second shifting mechanism. At this time, the power of 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. During the third gear operation, the transmission ratio between the high gear drive gear and the high gear driven gear is 1.5 to 3, preferably 1.5. Accordingly, a speed ratio of 3.75 to 13.5, preferably 6, is achieved through the first-stage reduction stage and the third gear transmission mechanism during the third gear operation.

[0036] Figure 1 The power transmission path of the electric drive axle during the neutral gear operation is also schematically shown. During the neutral gear operation, both the first gear sleeve and the second gear sleeve are in the disconnected position, thus disconnecting the connection between the low gear driven gear and the sun gear or the input gear hub of the differential assembly, and the connection between the high gear driven gear and the input gear hub of the differential assembly. At this time, no power is transmitted to the input shaft of the differential assembly, and the vehicle can coast in neutral. At this time, the torque of the main drive motor is transmitted to the low gear driven gear and the high gear driven gear through the first-stage reduction drive gear, the first-stage reduction driven gear, the low gear drive gear and the high gear drive gear. In the said embodiment, the power take-off can obtain power through the low gear driven gear or the high gear driven gear during the first gear, second gear, third gear and neutral gear operations according to specific working conditions and requirements.

[0037] Those skilled in the art should understand that the above specific embodiments are merely examples rather than limitations, and 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, that is, within the scope of the rights to be protected by the present invention.

Claims

1. An electric drive axle, which is used for an electric truck and has a main drive motor, a reducer 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. Among them, the first-stage reduction stage is composed of a first-stage reduction driving gear and a first-stage reduction driven gear that mesh with each other. The first-stage reduction driving gear is fixedly supported on the motor shaft. Among them, the first-stage reduction driven gear is fixedly connected coaxially with the low-gear driving gear and the high-gear driving gear. Among them, the torque of the main driving motor is transmitted to the differential assembly through the first-stage reduction stage via the first-gear transmission mechanism or the second-gear transmission mechanism or the third-gear transmission mechanism. Among them, the first-gear transmission mechanism is composed of a planetary gear reducer, a low-gear driving gear, and a low-gear driven gear. The second-gear transmission mechanism is composed of a low-gear driving gear and a low-gear driven gear. The third-gear transmission mechanism is composed of a high-gear driving gear and a high-gear driven gear. Among them, the planet carrier of the planetary gear reducer is connected to the differential housing for torque transmission. Among them, the ring gear of the planetary gear reducer is fixedly arranged on the housing of the electric drive axle.

2. The electric drive axle according to claim 1, wherein On the input shaft of the differential assembly, an input hub of the differential assembly is fixedly arranged. Among them, the input shaft of the differential assembly is arranged as a hollow shaft and is connected to the differential housing for torque transmission. The hollow shaft is coaxially supported on the circumferential outer sides of the left half shaft and the right half shaft of the vehicle. Among them, the low-gear driven gear and the high-gear driven gear are supported on the input shaft of the differential assembly through 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 on the input shaft of the differential assembly with the low-gear driven gear and the high-gear driven gear.

3. The electric drive axle according to claim 2, wherein The sun gear is arranged along the circumferential direction at an interval distance from the input shaft of the differential assembly on the outer side of the input shaft of the differential assembly.

4. The electric drive axle according to claim 1, wherein, During the first-gear operation, the first shifting mechanism connects the low-gear driven gear and the sun gear of the planetary gear reducer for torque transmission. During the second-gear operation, the first shifting mechanism disconnects the connection between the low-gear driven gear and the sun gear, and connects the low-gear driven gear and the input hub of the differential assembly for torque transmission. During the third-gear operation, the first shifting mechanism disconnects the connection between the low-gear driven gear and the input hub of the differential assembly, and the second shifting mechanism fixedly connects the high-gear driven gear and the input hub of the differential assembly.

5. The electric drive axle according to claim 1, wherein, The first shifting mechanism is composed of a first gear sleeve, a first hub arranged on the low-gear driven gear, and a sun gear hub arranged on the sun gear. During the first-gear operation, the first gear sleeve fixedly connects the first hub and the sun gear hub coaxially. The second shifting mechanism is composed of a second gear sleeve, a second hub arranged on the low-gear driven gear, and a third hub arranged on the high-gear driven gear. During the second-gear operation, the second gear sleeve fixedly connects the second hub and the input hub of the differential assembly. During the third-gear operation, the second gear sleeve fixedly connects the third hub and the input hub of the differential assembly.

6. The electric drive axle according to claim 1, wherein, In neutral operation, the first gear sleeve disconnects the connection between the low-speed 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-speed driven gear and the high-speed driven gear, thereby disconnecting the power connection between the differential assembly and the reduction gear assembly.

7. The electric drive axle 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-speed drive gear and the low-speed driven gear is 2 to 4, the transmission ratio between the high-speed drive gear and the high-speed driven gear is 1.5 to 3, and the planetary gear reducer as a whole achieves a transmission ratio of 2 to 4.

8. The electric drive axle according to claim 1, wherein The electric drive axle further has at least one auxiliary drive motor, and the auxiliary drive motor is coupled to the first-stage reduction driven gear through an auxiliary drive first-stage reduction drive gear. A power disengagement device is provided between the auxiliary drive motor and the auxiliary drive first-stage reduction drive gear.

9. The electric drive axle according to claim 8, wherein The main drive motor, the auxiliary drive motor, the reduction gear assembly and the 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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