Double-electric-drive-axle and double-gearbox gear shifting method and system

Abstract

The invention relates to a double-electric-drive-axle double-gearbox gear shifting method and system, and belongs to the field of double-electric-drive-axle control. The method comprises the following steps that during static gear shifting, according to a neutral gear returning instruction, a gearbox controller controls an auxiliary box of a corresponding gearbox to execute neutral gear returning operation, and a main box of the gearbox is kept at the current gear; and when the neutral gear is shifted to the starting gear, according to the starting gear shifting instruction, a gearbox controller controls an auxiliary box of a corresponding gearbox to execute starting gear shifting operation, and a main box of the gearbox is kept at the current gear. During operation, the auxiliary box of the corresponding gearbox executes the neutral gear returning operation, the main box keeps the current gear, then when the starting gear is shifted from the neutral gear, only the auxiliary box executes the starting gear shifting operation, half of the gear shifting time is saved, the gear shifting response speed is higher, and the driver feels better.

Description

Technical Field

[0001] This application relates to the field of dual electric drive axle control technology, and in particular to a dual electric drive axle dual gearbox shifting method and system. Background Technology

[0002] Currently, there are relatively few commercial pure electric tractor models on the market equipped with dual electric drive axles and dual gearboxes. This type of gearbox consists of a main gearbox and an auxiliary gearbox, and a gear is formed by coupling the gears of the main gearbox and the auxiliary gearbox.

[0003] When shifting gears statically, the main gearbox is usually shifted first, followed by the auxiliary gearbox. When returning to neutral, both the main and auxiliary gearboxes need to be returned to neutral. This results in a slow shift response because operating both the main and auxiliary gearboxes is equivalent to shifting gears twice. The driver feels that the gears are not responsive and the shifting is sluggish.

[0004] Shift lag in dual-transmission systems means that the shifting actions of the two transmissions are not completely synchronized. When one transmission has completed a shift while the other is still in the process of shifting, there will be a brief mismatch or interruption in power transmission. This power interruption will lead to unstable vehicle operation and will also exacerbate shift lag.

[0005] Furthermore, the vehicle has only one instrument cluster, and the information it conveys to the driver regarding the current gear is limited to just one gear. During frequent gear changes, coupled with shift lag and interruptions, the gear display system also suffers from incorrect gear display during gear shifts. This invention aims to effectively solve these problems by optimizing the shift control strategy of the dual-transmission system, thereby improving the intelligence level of gear shifting and ultimately enhancing the overall vehicle performance and driving experience. Summary of the Invention

[0006] This application provides a dual-electric drive axle dual-transmission shifting method and system to solve a series of problems caused by the lag in gear shifting of dual transmissions in related technologies, which negatively affect the safety and service life of vehicles.

[0007] In a first aspect, a dual-electric drive axle dual-transmission shifting method is provided, comprising the following steps: when shifting in a static state, according to the return-to-neutral command, the transmission controller controls the corresponding auxiliary transmission to perform a return-to-neutral operation, and keeps the primary transmission of that transmission in the current gear; when shifting from neutral to starting gear, according to the starting gear shift command, the transmission controller controls the corresponding auxiliary transmission to perform a starting gear shift operation, and keeps the primary transmission of that transmission in the current gear.

[0008] In some embodiments, when accelerating or decelerating, the gearbox on the first axle and the gearbox on the second axle are driven to upshift or downshift in a designed sequence, and the gearbox that upshifts or downshifts first maintains the current gear while performing the upshift or downshift operation.

[0009] In some embodiments, when accelerating, the designed sequence includes: the transmission on the first axle upshifts first, and the transmission on the second axle upshifts last; when decelerating, the designed sequence includes: the transmission on the second axle downshifts first, and the transmission on the first axle downshifts last.

[0010] In some embodiments, when accelerating, the designed sequence includes: the transmission on the first axle upshifts first, and the transmission on the second axle upshifts last; when decelerating, the designed sequence includes: the transmission on the first axle downshifts first, and the transmission on the second axle downshifts last.

[0011] In some embodiments, when accelerating, the designed sequence includes: the transmission on the second axle upshifts first, followed by the transmission on the first axle upshifting later; when decelerating, the designed sequence includes: the transmission on the first axle downshifts first, followed by the transmission on the second axle downshifting later.

[0012] In some embodiments, when accelerating, the designed sequence includes: the transmission on the second axle upshifts first, followed by the transmission on the first axle upshifting later; when decelerating, the designed sequence includes: the transmission on the second axle downshifts first, followed by the transmission on the first axle downshifting later.

[0013] In some embodiments, when the gearboxes on the first axle and the gearboxes on the second axle have different gears, the method further includes controlling the motors on the first axle and the second axle to make the wheel speeds of the wheels on the first axle and the wheels on the second axle the same.

[0014] In some embodiments, the method further includes the following steps: receiving the current gear positions of the transmissions on the first axle and the second axle; comparing the current gear position, the initial gear position, and the target gear position, wherein the initial gear position is the gear position the transmission is in before shifting, and the target gear position is the gear position the transmission is in after shifting; when the current gear positions of the transmissions on the first axle and the second axle are the same, displaying the gear position as the current gear position via an instrument panel; when the current gear positions of the transmissions on the first axle and the second axle are different, displaying the gear position as the initial gear position via an instrument panel.

[0015] Secondly, a dual-electric drive axle dual-gearbox shifting system is provided, comprising: a transmission device including a gearbox controller and a gearbox connected thereto, the gearbox including a main gearbox and an auxiliary gearbox connected to each other; a drive axle including a first axle and a second axle, both the first axle and the second axle being equipped with the transmission device; wherein, the gearbox controller is used to: when static shifting, according to a return-to-neutral command, control the corresponding auxiliary gearbox of the gearbox to perform a return-to-neutral operation, and keep the main gearbox of the gearbox in the current gear; when shifting from neutral to starting gear, according to a starting gear engagement command, control the corresponding auxiliary gearbox of the gearbox to perform a starting gear engagement operation, and keep the main gearbox of the gearbox in the current gear.

[0016] In some embodiments, the drive axle is further provided with a motor, which is used to drive the wheels on the first axle to have the same wheel speed as the wheels on the second axle when the gearboxes on the first axle and the gearboxes on the second axle are in different gears.

[0017] The beneficial effects of the technical solution provided in this application include: This application provides a dual-electric drive axle dual-transmission shifting method and system. Since gear shifting lag is a direct cause of power interruption and gear position display errors, effectively reducing or eliminating lag significantly improves these problems. Therefore, in the dual-electric drive axle dual-transmission shifting method, during static shifting, only the transmission controller controls the corresponding auxiliary transmission to return to neutral, while the primary transmission maintains its current gear. This reduces shifting time, resulting in faster shifting response and a better driver experience. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 The overall structural schematic diagram provided in this application embodiment; In the diagram: 1. Transmission controller; 10. Main gearbox; 11. Auxiliary gearbox; 2. First axle; 3. Second axle; 4. Vehicle controller; 5. Instrument panel. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] This application provides a dual-electric drive axle dual-transmission shifting method, which can solve a series of problems caused by the gear shifting delay of dual transmissions, and the defects that negatively affect the safety and service life of vehicles.

[0022] See Figure 1 As shown in the figure, this application embodiment provides a dual electric drive axle dual gearbox shifting method, including the following steps: when shifting gears statically, according to the return to neutral command, the gearbox controller 1 controls the corresponding auxiliary gearbox 11 of the gearbox to perform the return to neutral operation, and keeps the main gearbox 10 of the gearbox in the current gear position; when shifting from neutral to starting gear, according to the starting gear shift command, the gearbox controller 1 controls the corresponding auxiliary gearbox 11 of the gearbox to perform the starting gear shift operation, and keeps the main gearbox 10 of the gearbox in the current gear position.

[0023] The purpose of this step is to shift the auxiliary gearbox 11 of the corresponding transmission to neutral while maintaining the current gear position of the primary gearbox 10 when the vehicle is stationary. When shifting from neutral to starting gear, the auxiliary gearbox 11 engages the starting gear while maintaining the current gear position of the primary gearbox 10. During operation, the driver sends a neutral shift command through the vehicle controller 4. Upon receiving the command, the transmission controller 1 controls the auxiliary gearbox 11 to execute the neutral shift command. Specifically, the transmission controller 1 primarily uses sensors to detect the current gear positions of the primary and auxiliary gearboxes 10 and 11, confirming that the primary gearbox is in a specific gear (e.g., 1st or 2nd) and the auxiliary gearbox 11 is not in neutral. When the transmission controller 1 sends a control signal to the auxiliary gearbox 11, it drives the auxiliary gearbox 11 to neutral; the current gear position of the primary gearbox 10 remains unchanged. Finally, the driver can confirm the completion of the operation by displaying a feedback signal on the instrument panel 5.

[0024] To engage the starting gear from neutral, the driver sends a starting gear engagement command through the vehicle controller 4. Upon receiving the command, the transmission controller 1 initiates the starting gear engagement operation by controlling the corresponding transmission's master gearbox 10. Specifically, the transmission controller 1 uses sensors to detect the current gear positions of the master gearbox 10 and auxiliary gearbox 11, confirming that the master gearbox 10 is in a specific gear (e.g., 1st or 2nd gear) and the auxiliary gearbox 11 is in neutral. The transmission controller 1 then sends a control signal to the auxiliary gearbox 11, driving it to engage the starting gear (e.g., 1st gear). The master gearbox 10 remains in its current gear position without any further action. The transmission controller 1 confirms through sensors that the auxiliary gearbox 11 has successfully engaged the starting gear, while the master gearbox 10 remains in its current gear position, displaying the starting gear status on the instrument panel 5. In this operation, the master gearbox 10 and auxiliary gearbox 11 form a two-stage transmission structure; the master gearbox 10 not returning to neutral does not pose a safety hazard.

[0025] In summary, by implementing a neutral shift control strategy when the vehicle is stationary, the main gearbox 10 and auxiliary gearbox 11 of the transmission need to perform a shift when shifting to neutral. When shifting from neutral to starting gear, the main gearbox 10 is already in the starting gear since it has not been shifted to neutral, so only the auxiliary gearbox 11 needs to be engaged. This control reduces the shifting time by half, resulting in faster shifting response and a better driver experience. Once the lag problem is solved, other effects caused by the lag will be further mitigated.

[0026] In this application, to further reduce the impact of hysteresis on power interruption, the method can further include driving the transmissions on the first axle 2 and the second axle 3 to upshift or downshift in a designed sequence during acceleration or deceleration. During the upshift or downshift operation, the transmission that upshifts or downshifts first maintains its current gear while the transmission that upshifts or downshifts later maintains its current gear. The first axle 2 may include, but is not limited to, being a middle axle, and the second axle 3 may include, but is not limited to, being a rear axle. This operation, by controlling the transmissions on the first axle 2 and the second axle 3 to shift gears separately and maintaining uninterrupted power to one axle during gear shifts, avoids power interruption.

[0027] This application drives the transmission on the first axle 2 and the transmission on the second axle 3 to upshift or downshift according to a designed sequence, specifically including but not limited to four design strategy sequences. The first strategy: When accelerating, the designed sequence includes: the transmission on the first axle 2 upshifts first, followed by the transmission on the second axle 3; when decelerating, the designed sequence includes: the transmission on the second axle 3 downshifts first, followed by the transmission on the first axle 2. After the driver issues an acceleration and shift command through the vehicle controller 4, the transmission controller 1 connected to the first axle 2 controls the corresponding transmission to upshift first. During this upshift, the transmission on the second axle 3 maintains the current gear and continues to output power. After the transmission on the first axle 2 completes the upshift, it maintains the same gear and continues to output power, after which the transmission on the second axle 3 performs the upshift. When decelerating and downshifting, after the driver issues an acceleration and shift command through the vehicle controller 4, the transmission controller 1 connected to the second axle 3 controls the corresponding transmission to downshift first. During the upshifting of the transmission, the transmission on the first axle 2 maintains the current gear and continues to output power. After the transmission on the second axle 3 completes the downshift, it maintains the same gear and continues to output power. Then, the transmission on the first axle 2 performs the downshifting operation.

[0028] The second strategy, when accelerating, involves the following sequence: the transmission on the first axle 2 upshifts first, followed by the transmission on the second axle 3. When decelerating, the following sequence involves the following: the transmission on the first axle 2 downshifts first, followed by the transmission on the second axle 3. After the driver issues an acceleration shift command via the vehicle controller 4, the transmission controller 1 controls the corresponding transmission on the first axle 2 to upshift first. During this upshift, the transmission on the second axle 3 maintains its current gear and continues to output power. After the transmission on the first axle 2 completes the upshift, it maintains the same gear and continues to output power, after which the transmission on the second axle 3 performs the upshift. Similarly, when decelerating and downshifting, after the driver issues an acceleration shift command via the vehicle controller 4, the transmission controller 1 connected to the first axle 2 controls the corresponding transmission to downshift first. During this upshift, the transmission on the second axle 3 maintains its current gear and continues to output power. After the transmission on the first axle 2 completes the downshift, it maintains the same gear and continues to output power, after which the transmission on the second axle 3 performs the downshift.

[0029] The third strategy: When accelerating, the designed sequence includes: the transmission on the second axle 3 upshifts first, followed by the transmission on the first axle 2; when decelerating, the designed sequence includes: the transmission on the first axle 2 downshifts first, followed by the transmission on the second axle 3. After the driver issues an acceleration shift command via the vehicle controller 4, the transmission controller 1 connected to the second axle 3 controls the corresponding transmission to upshift first. During this upshift, the transmission on the first axle 2 maintains its current gear and continues to output power. After the transmission on the second axle 3 completes the upshift, it maintains the same gear and continues to output power, after which the transmission on the first axle 2 performs the upshift. When decelerating and downshifting, after the driver issues an acceleration shift command via the vehicle controller 4, the transmission controller 1 connected to the first axle 2 controls the corresponding transmission to downshift first. During this upshift, the transmission on the second axle 3 maintains its current gear and continues to output power. After the transmission on the first axle 2 completes the downshift, it maintains the same gear and continues to output power, after which the transmission on the second axle 3 performs the downshift.

[0030] When accelerating, the designed shift sequence is as follows: the transmission on the second axle 3 upshifts first, followed by the transmission on the first axle 2. When decelerating, the designed shift sequence is as follows: the transmission on the second axle 3 downshifts first, followed by the transmission on the first axle 2. After the driver issues an acceleration shift command via the vehicle controller 4, the transmission controller 1 connected to the second axle 3 controls the corresponding transmission to upshift first. During this upshift, the transmission on the first axle 2 maintains its current gear and continues to output power. After the transmission on the second axle 3 completes the upshift, it maintains the same gear and continues to output power, after which the transmission on the first axle 2 performs the upshift. When decelerating and downshifting, after the driver issues an acceleration shift command via the vehicle controller 4, the transmission controller 1 connected to the second axle 3 controls the corresponding transmission to downshift first. During this upshift, the transmission on the first axle 2 maintains its current gear and continues to output power. After the transmission on the second axle 3 completes the downshift, it maintains the same gear and continues to output power, after which the transmission on the first axle 2 performs the downshift.

[0031] In this application, since the first axle 2 and the second axle 3 shift gears separately, during the separate shifting process—that is, when the gearboxes on the first axle 2 and the second axle 3 have different gear ratios—the method further includes controlling the motors on the first axle 2 and the second axle 3 to ensure that the wheel speeds of the wheels on the first axle 2 and the second axle 3 are the same. The motors and gearboxes are connected, with the gearboxes mounted in the center of the axle and the wheels connected to both ends of the axle. When the gearboxes on the first axle and the second axle have different gear ratios, the speed ratios of the gearboxes on the first axle and the second axle are different. At this time, it is necessary to control the speeds of the motors on the first axle and the second axle according to the speed ratios to ensure that the speeds output to the wheels are the same, thus preventing tire wear.

[0032] In this application, since the entire vehicle has only one instrument panel 5, and the information transmitted to the driver by the instrument panel 5 regarding the current gear position is only allowed to be one current gear, the gear position display system, during frequent gear shifts, also suffers from shift lag and interruption issues, leading to display gear position errors when shifting gears. Therefore, to further reduce the display errors of the instrument panel 5 due to lag, the method further includes the following steps: receiving the current gear positions of the transmissions on the first axle 2 and the second axle 3; comparing the current gear position, the initial gear position, and the target gear position, wherein the initial gear position is the gear the transmission is in before shifting, and the target gear position is the gear the transmission is in after shifting; when the current gear positions of the transmissions on the first axle 2 and the second axle 3 are the same, the instrument panel 5 displays the current gear position; when the current gear positions of the transmissions on the first axle 2 and the second axle 3 are different, the instrument panel 5 displays the initial gear position.

[0033] In specific operation, the transmission controller 1 connected to the first axle 2 and the transmission controller 1 connected to the second axle 3 monitor the message information of the current gear position of the transmissions on the first axle 2 and the second axle 3 in real time, and send the message information to the vehicle controller 4. The vehicle controller 4 identifies and receives the current gear position of the transmissions on the first axle 2 and the second axle 3 through the message information. Then, the current gear position, initial gear position, and target gear position of the transmissions on the first axle 2 and the second axle 3 are compared. The initial gear position is the gear the transmission is in before shifting, and the target gear position is the gear the transmission is in after shifting. If the current gear position of the transmissions on the first axle 2 and the second axle 3 is the same, the gear position is displayed as the current gear position on the instrument panel 5. If the current gear positions of the transmissions on the first axle 2 and the second axle 3 are different, the gear position is displayed as the initial gear position on the instrument panel 5.

[0034] To illustrate this more clearly, let's take a specific example of the gear display during acceleration: After the first axle 2 shifts from 1st to 2nd gear, the transmission controller 1 of the first axle 2 will send a message indicating that it is currently in 2nd gear. At this time, the transmission of the second axle 3 has not yet completed the shift and is still in 1st gear. Therefore, the transmission controller 1 of the second axle 3 will send a message indicating that it is currently in 2nd gear. After the vehicle controller 4 receives the messages from the two transmission controllers, it compares them and finds that one transmission is in 1st gear and the other is in 2nd gear. Therefore, the display message sent by the vehicle controller 4 to the instrument panel 5 will remain in 1st gear. Only when the transmission controller 1 of the second axle 3 sends a message indicating that it has shifted from 1st to 2nd gear, and both transmissions are in 2nd gear, will the vehicle controller 4 send a message to the instrument panel 5 indicating that it is currently in 2nd gear.

[0035] In some alternative embodiments, see Figure 1This application provides a dual-electric drive axle dual-gearbox shifting system, including: a transmission device and a drive axle. The transmission device includes a gearbox controller 1 and a gearbox connected thereto. The gearbox includes a main gearbox 10 and an auxiliary gearbox 11 connected to each other. The drive axle includes a first axle 2 and a second axle 3, which may include, but are not limited to, being a middle axle and a rear axle respectively. A transmission device is provided on both the first axle 2 and the second axle 3. The gearbox controller 1 is used to: when static shifting, according to a return-to-neutral command, control the auxiliary gearbox 11 of the corresponding gearbox to perform a return-to-neutral operation, and keep the main gearbox 10 of the gearbox in the current gear position; when shifting from neutral to starting gear, according to a starting gear engagement command, control the auxiliary gearbox 11 of the corresponding gearbox to perform a starting gear engagement operation, and keep the main gearbox 10 of the gearbox in the current gear position.

[0036] The drive axle is also equipped with a motor, which is used to drive the wheels on the first axle 2 to have the same wheel speed as the wheels on the second axle 3 when the gearbox on the first axle 2 and the gearbox on the second axle 3 are in different gears.

[0037] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0038] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0039] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for shifting gears using a dual-electric drive axle and a dual-gearbox, characterized in that, The method includes the following steps: When static shifting occurs, according to the return to neutral command, the corresponding auxiliary gearbox (11) of the gearbox is controlled by the gearbox controller (1) to perform the return to neutral operation, and the main gearbox (10) of the gearbox is kept in the current gear. When shifting from neutral to starting gear, the corresponding auxiliary gearbox (11) of the gearbox is controlled by the gearbox controller (1) to perform the starting gear operation according to the starting gear shift command, and the main gearbox (10) of the gearbox is kept in the current gear.

2. The dual-electric drive axle dual-gear shifting method as described in claim 1, characterized in that: When accelerating or decelerating, the gearbox on the first axle (2) and the gearbox on the second axle (3) are driven to upshift or downshift in the designed sequence. During the upshift or downshift operation, the gearbox that upshifts or downshifts first maintains the current gear.

3. The dual-electric drive axle dual-gear shifting method as described in claim 2, characterized in that: When accelerating, the design sequence includes: the gearbox on the first axle (2) shifts up first, and the gearbox on the second axle (3) shifts up later; When decelerating, the design sequence includes: the gearbox on the second axle (3) downshifts first, and the gearbox on the first axle (2) downshifts later.

4. The dual-electric drive axle dual-gear shifting method as described in claim 2, characterized in that: When accelerating, the design sequence includes: the gearbox on the first axle (2) shifts up first, and the gearbox on the second axle (3) shifts up later; When decelerating, the design sequence includes: the gearbox on the first axle (2) downshifts first, and the gearbox on the second axle (3) downshifts later.

5. The dual-electric drive axle dual-gear shifting method as described in claim 2, characterized in that: When accelerating, the design sequence includes: the gearbox on the second axle (3) upshifts first, and the gearbox on the first axle (2) upshifts later; When decelerating, the design sequence includes: the gearbox on the first axle (2) downshifts first, and the gearbox on the second axle (3) downshifts later.

6. The dual-electric drive axle dual-gear shifting method as described in claim 2, characterized in that: When accelerating, the design sequence includes: the gearbox on the second axle (3) upshifts first, and the gearbox on the first axle (2) upshifts later; When decelerating, the design sequence includes: the gearbox on the second axle (3) downshifts first, and the gearbox on the first axle (2) downshifts later.

7. The dual-electric drive axle dual-gear shifting method as described in claim 2, characterized in that: When the gearbox on the first axle (2) and the gearbox on the second axle (3) are in different gears, the method further includes: Control the motors on the first axle (2) and the second axle (3) so that the wheel speeds of the wheels on the first axle (2) and the wheels on the second axle (3) are the same.

8. A dual-electric drive axle dual-gear shifting method as described in claim 2, characterized in that: The method further includes the following steps: Receive the current gear position of the gearbox on the first axle (2) and the gearbox on the second axle (3); Compare the current gear, the initial gear, and the target gear, wherein the initial gear is the gear the transmission is in before shifting, and the target gear is the gear the transmission is in after shifting; When the current gear of the gearbox on the first axle (2) and the gearbox on the second axle (3) are the same, the gear is displayed as the current gear through the instrument (5); When the current gear position of the gearbox on the first axle (2) and the gearbox on the second axle (3) are different, the gear position is displayed as the initial gear position through the instrument (5).

9. A dual-electric drive axle dual-gear shifting system, characterized in that: The transmission device includes a gearbox controller (1) and a gearbox connected thereto, the gearbox including a main gearbox (10) and a secondary gearbox (11) connected to each other. The drive axle includes a first axle (2) and a second axle (3), and the speed change device is provided on both the first axle (2) and the second axle (3); The transmission controller (1) is used to: when static shifting, according to the return to neutral command, control the corresponding transmission auxiliary gearbox (11) to perform the return to neutral operation, and keep the transmission master gearbox (10) in the current gear position; when shifting from neutral to starting gear, according to the starting gear shift command, control the corresponding transmission auxiliary gearbox (11) to perform the starting gear shift operation, and keep the transmission master gearbox (10) in the current gear position.

10. The dual electric drive axle dual gearbox shifting system as described in claim 9, characterized in that: The drive axle is also equipped with a motor, which is used to drive the wheels on the first axle (2) and the wheels on the second axle (3) to have the same wheel speed when the gearbox on the first axle (2) and the gearbox on the second axle (3) are in different gears.

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