An electrically driven axle and a method of controlling the same

Abstract

This application discloses an electric drive axle and its control method, relating to the field of vehicle transmission technology. The electric drive axle includes a first drive motor, a second drive motor, a first shaft system, a first shifting mechanism, a second shaft system, a second shifting mechanism, a third shaft system, a controller, and a differential assembly. The first shifting mechanism can switch between a first neutral gear, a first gear, and a second gear. The second shifting mechanism has a neutral gear, a third gear, and a fourth gear. The controller is connected to both the first and second shifting mechanisms. When the controller controls the first drive motor to shift gears, it simultaneously controls the second shifting mechanism to be in the fourth gear. When the controller controls the second drive motor to shift gears, it simultaneously controls the first shifting mechanism to be in either the first gear or the second gear. The electric drive axle provided by this application can ensure uninterrupted power during gear shifting, improve shifting smoothness, and thus enhance vehicle driving comfort.

Description

Technical Field

[0001] This application relates to the field of vehicle transmission technology, and in particular to an electric drive axle and its control method. Background Technology

[0002] With the increasing popularity of pure electric heavy-duty trucks (hereinafter referred to as pure electric heavy trucks), electric drive axles, as core components, are also undergoing technological innovation. As pure electric heavy trucks often face special working conditions such as climbing, getting out of trouble, and long-distance transportation, higher requirements are placed on various factors such as torque, integration, and energy consumption of the drive system.

[0003] However, existing electric drive axles suffer from power interruption during gear shifts, affecting shift smoothness and resulting in poor driving comfort; moreover, they are prone to motor drag losses, affecting system economy. Summary of the Invention

[0004] In view of the above problems, this application provides an electric drive axle and its control method to improve shift smoothness and thus enhance vehicle driving comfort. The specific solution is as follows:

[0005] The first aspect of this application provides an electric drive bridge, comprising:

[0006] The system comprises a first drive motor, a second drive motor, a first shaft system, a first shift mechanism, a second shaft system, a second shift mechanism, a third shaft system, a controller, and a differential assembly.

[0007] Wherein, the first output shaft of the first drive motor is coaxially connected to an output transmission component, the output transmission component is driven to the first torque input end of the third shaft system, the third shaft system torque output end is driven to an input transmission component, the input transmission component is coaxially arranged with the first shaft system and can rotate relative to it;

[0008] The first shaft system's torque output end is connected to the differential assembly in a transmission connection.

[0009] The first shifting mechanism is capable of switching between a first neutral gear, a first gear, and a second gear. The first shifting mechanism is connected to the first shaft system. When the first shifting mechanism is in the first gear, the shaft system-second torque input end of the first shaft system is connected to the input transmission component. When the first shifting mechanism is in the second gear, the shaft system-first torque input end of the first shaft system is connected to the first output shaft of the first drive motor.

[0010] The second shifting mechanism is connected to the second output shaft of the second drive motor; the second shifting mechanism has a neutral position, a third position, and a fourth position. When the second shifting mechanism is in the third position, the second output shaft of the second drive motor is driven to the first torque input end of the second shaft system; when the second shifting mechanism is in the fourth position, the second output shaft of the second drive motor is driven to the second torque input end of the second shaft system.

[0011] The first torque output end of the second shaft system is driven to the second torque input end of the third shaft system, the second torque output end of the second shaft system is driven to the differential assembly, the first torque input end of the second shaft system is linked to the first torque output end of the second shaft system, and the second torque input end of the second shaft system is linked to the second torque output end of the second shaft system.

[0012] The controller is connected to both the first shifting mechanism and the second shifting mechanism. When the controller controls the first drive motor to shift gears, it simultaneously controls the second shifting mechanism to be in the fourth gear position. When the controller controls the second drive motor to shift gears, it simultaneously controls the first shifting mechanism to be in the first gear position or the second gear position.

[0013] In one possible implementation, the electric drive bridge also includes:

[0014] A clutch and a torque amplifier are configured together on the torque input end of the third shaft system or the differential assembly or on the transmission path between the differential assembly and the drive half-shaft of the wheel; wherein the clutch is capable of switching the engagement and disengagement of the torque amplifier from the transmission path.

[0015] In one possible implementation, in the aforementioned electric drive axle, the clutch and the torque amplifier are arranged as a set on the transmission path of the third shaft system; wherein:

[0016] The third axis system is divided into an input axis segment and an output axis segment;

[0017] The torque input terminal of the torque amplifier is connected to the input shaft segment via a transmission connection.

[0018] The output end of the clutch is connected to the output shaft segment, and the input end of the clutch is connected to the input shaft segment and the torque output end of the torque amplifier in a switching transmission connection.

[0019] Under the target operating condition, the controller controls the input end of the clutch to be connected to the torque output end of the torque amplifier.

[0020] In one possible implementation, in the above-mentioned electric drive axle, the second shifting mechanism includes a first shifting part and a second shifting part, wherein the first shifting part is capable of switching between a second neutral gear and the third gear, and the second shifting part is capable of switching between a third neutral gear and the fourth gear.

[0021] The neutral gear position includes a second neutral gear position and a third neutral gear position; when the first shifting part is in the third gear position and the second shifting part is in the fourth gear position, the first torque input end of the second shaft system is connected to the second torque input end of the second shaft system.

[0022] The electric drive axle includes a dual-motor first-gear operating mode, a dual-motor second-gear operating mode, and a dual-motor third-gear operating mode. In the dual-motor first-gear operating mode, the controller controls the first shifting mechanism to be in the first gear, and simultaneously controls the second shifting mechanism to be in the third gear. In the dual-motor second-gear operating mode, the controller controls the second shifting mechanism to be in both the third and fourth gears, and controls the first shifting mechanism to be in the first neutral gear. In the dual-motor third-gear operating mode, the controller controls the first shifting mechanism to be in the second gear, and simultaneously controls the second shifting mechanism to be in the third gear.

[0023] In one possible implementation, in the aforementioned electric drive axle, when switching from the dual-motor first-gear operation mode to the dual-motor second-gear operation mode, the controller first controls the second shifting mechanism to exit the third gear position, placing the second shifting mechanism in the neutral gear position, while keeping the first shifting mechanism in the first gear position; then controls the second shifting mechanism to enter the fourth gear position, and raises the second drive motor to gear 2; next, controls the first shifting mechanism to exit the first gear position, placing the first shifting mechanism in the first neutral gear position, while keeping the second shifting mechanism in the fourth gear position; finally, controls the second shifting mechanism to simultaneously enter the third gear position, and raises the first drive motor to gear 2.

[0024] When switching from the dual-motor two-speed operation mode to the dual-motor three-speed operation mode, the controller first controls the second shifting mechanism to exit the third gear while keeping the second shifting mechanism in the fourth gear; then controls the first shifting mechanism to be in the second gear and raises the first drive motor to the third gear; then controls the second shifting mechanism to exit the fourth gear while keeping the first shifting mechanism in the second gear; finally, controls the second shifting mechanism to be in the third gear and raises the second drive motor to the third gear.

[0025] In one possible implementation, the aforementioned electric drive axle further includes an output shaft system, wherein the second torque output end of the second shaft system and the shaft system-torque output end of the first shaft system are both connected to the differential assembly via the output shaft system.

[0026] In one possible implementation, in the above-described electric drive axle, the first drive motor, the second drive motor, the first shaft system, the first shift mechanism, the second shaft system, the second shift mechanism, the third shaft system, and the output shaft system are arranged on the same side of the differential assembly.

[0027] A second aspect of this application provides a control method for an electric drive bridge, applied to an electric drive bridge as described in the first aspect of this application and any implementation thereof, the control method for the electric drive bridge comprising:

[0028] When controlling the first drive motor to shift gears, the second shift mechanism is simultaneously controlled to be in the fourth gear position; when controlling the second drive motor to shift gears, the first shift mechanism is simultaneously controlled to be in the first gear position or the second gear position.

[0029] In one possible implementation, the control method for the electric drive bridge includes:

[0030] When switching from dual-motor first-gear operation mode to dual-motor second-gear operation mode, firstly, the second shifting mechanism is controlled to exit the third gear position, so that the second shifting mechanism is in the neutral gear position, while the first shifting mechanism is kept in the first gear position; then, the second shifting mechanism is controlled to enter the fourth gear position, and the second drive motor is raised to gear 2; next, the first shifting mechanism is controlled to exit the first gear position, so that the first shifting mechanism is in the first neutral gear position, while the second shifting mechanism is kept in the fourth gear position; finally, the second shifting mechanism is controlled to enter the third gear position, and the first drive motor is raised to gear 2.

[0031] When switching from a dual-motor two-speed operation mode to a dual-motor three-speed operation mode, firstly, the second shifting mechanism is controlled to exit the third gear while maintaining the second shifting mechanism in the fourth gear; then, the first shifting mechanism is controlled to be in the second gear, and the first drive motor is raised to the third gear; next, the second shifting mechanism is controlled to exit the fourth gear while maintaining the first shifting mechanism in the second gear; finally, the second shifting mechanism is controlled to be in the third gear, and the second drive motor is raised to the third gear.

[0032] In one possible implementation, the electric drive axle is applied to the vehicle, and the control method includes:

[0033] Obtain the total required torque T at the vehicle wheel endsreq ;

[0034] Let the output torque proportionality coefficient of the first drive motor be β, and the output torque proportionality coefficient of the second drive motor be 1-β; let β take n random values ​​in the continuous value range [0,1], and calculate the random output torque of the first drive motor for each random value. and the random output torque of the second drive motor ;

[0035] According to the random output torque T of the first drive motor EM1 Obtain the random motor efficiency value of the first drive motor; based on the random output torque T of the second drive motor... EM2 Obtain the random motor efficiency value of the second drive motor;

[0036] Calculate the random total efficiency value of the two motors after superimposing the random motor efficiency values ​​of the first drive motor and the second drive motor for each random value. Select the random value corresponding to the largest random total efficiency value of the two motors as the target value of the output torque proportional coefficient β of the first drive motor.

[0037] In one possible implementation, the electric drive axle is applied to the vehicle, and the control method includes:

[0038] Select different pedal openings for the vehicle, and at each pedal opening, plot the drive motor efficiency curve for each gear as a function of the vehicle speed.

[0039] At each pedal opening, the vehicle speed corresponding to the intersection point of the two drive motor efficiency curves of two adjacent gears is selected as the target shift speed at that pedal opening.

[0040] Connect the target shift speeds obtained at different pedal openings and plot them as different gear shift curves with pedal opening and vehicle speed as coordinate axes.

[0041] Based on the vehicle's real-time pedal opening and shifting requirements, the real-time target shifting speed is obtained through the different gear shifting curves, and the target shifting operation of the drive motor is executed at the real-time target shifting speed.

[0042] Wherein, the drive motor is the first drive motor and / or the second drive motor; the shifting requirements include shifting between first and second gear and shifting between second and third gear.

[0043] In one possible implementation, the electric drive axle further includes a clutch and a torque amplifier, both of which are configured together on the torque input end of the third shaft system or the differential assembly or on the transmission path between the differential assembly and the drive half-shaft of the wheel; wherein the clutch is capable of switching the engagement and disengagement of the torque amplifier from the transmission path.

[0044] The control method includes:

[0045] Under the target operating condition, the input end of the clutch is connected to the torque output end of the torque amplifier.

[0046] By means of the above technical solution, in the electric drive axle provided in this application, when the controller controls the first drive motor to shift gears, it simultaneously controls the second shifting mechanism to be in the fourth gear. At this time, the second output shaft of the second drive motor is driven to the second torque input end of the second shaft system, and the second torque output end of the second shaft system is driven to the differential assembly. Power can be provided by the second drive motor to ensure that the power is not interrupted during gear shifting. When the controller controls the second drive motor to shift gears, it simultaneously controls the first shifting mechanism to be in the first gear or the second gear. When the first shifting mechanism is controlled to be in the first gear, the second torque input end of the first shaft system is driven to the input transmission component. The input transmission component is connected to the output transmission component coaxially connected to the output shaft of the first drive motor through the third shaft system. At this time, power can be provided by the first drive motor to ensure that the power is not interrupted during gear shifting. When the first shifting mechanism is controlled to be in the second gear, the first torque input end of the first shaft system is driven to the output shaft of the first drive motor. At this time, power can be provided by the first drive motor to ensure that the power is not interrupted during gear shifting.

[0047] Therefore, the electric drive axle provided in this application can ensure uninterrupted power during gear shifting, improve shifting smoothness, and thus enhance vehicle driving comfort.

[0048] Furthermore, since the first torque output end of the second shaft system is connected to the output shaft of the first drive motor via the third shaft system, this application can disconnect the second output shaft of the second drive motor from the first torque input end of the second shaft system by disengaging the third gear of the second shift mechanism, thereby disconnecting the transmission between the second drive motor and the first drive motor. Both motors can operate independently and be completely disengaged, enabling coasting in neutral, reducing motor towing losses, improving system economy, and meeting the towing operation needs when the vehicle breaks down. Attached Figure Description

[0049] The above and other features, advantages, and aspects of the embodiments of this disclosure will become more apparent from the accompanying drawings and the following detailed description. Throughout the drawings, the same or similar reference numerals denote the same or similar elements. It should be understood that the drawings are schematic, and the originals and elements are not necessarily drawn to scale.

[0050] Figure 1 This is a schematic diagram of the structure of the electric drive bridge provided in the first embodiment of this application.

[0051] Figure 2 This is a schematic diagram of the structure of the electric drive bridge provided in the second embodiment of this application.

[0052] Figure 3 This is a schematic diagram of a first shaft system provided in an embodiment of this application.

[0053] Figure 4 This is a schematic diagram of a second shaft system provided in an embodiment of this application.

[0054] Figure 5 A schematic diagram of the structure in which the clutch and torque amplifier are arranged in the third shaft system according to an embodiment of this application.

[0055] Figure 6 This is a schematic diagram of the structure of the electric drive bridge provided in the third embodiment of this application.

[0056] Figure 7 This is a schematic diagram of the structure of the electric drive bridge provided in the fourth embodiment of this application.

[0057] Figure 8 This is a schematic diagram of the structure of the electric drive bridge provided in the fifth embodiment of this application.

[0058] Figure 9 This is a schematic diagram of the structure of the electric drive bridge provided in the sixth embodiment of this application.

[0059] Figure 10 This is a schematic flowchart of a control method for an electric drive bridge provided in an embodiment of this application.

[0060] Figure 11 This is another schematic flowchart illustrating the control method for the electric drive bridge provided in an embodiment of this application.

[0061] Figure 12 A schematic diagram of an energy-optimal shift curve provided in this application. Detailed Implementation

[0062] The embodiments of this application are described below with reference to the accompanying drawings. The terminology used in the implementation section of this application is for explaining specific embodiments only and is not intended to limit the scope of this application.

[0063] The embodiments of this application will now be described with reference to the accompanying drawings. Those skilled in the art will recognize that, with technological advancements and the emergence of new scenarios, the technical solutions provided in the embodiments of this application are equally applicable to similar technical problems.

[0064] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms are interchangeable where appropriate; this is merely a way of distinguishing objects with the same attributes in the embodiments of this application. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, so that a process, method, system, product, or apparatus that comprises a series of elements is not necessarily limited to those elements, but may include other elements not explicitly listed or inherent to those processes, methods, products, or apparatuses.

[0065] The first aspect of this application provides an electric drive bridge, such as... Figures 1-9 As shown, the electric drive bridge includes:

[0066] The system comprises a first drive motor 101, a second drive motor 102, a first shaft system 103, a first shifting mechanism 104, a second shaft system 105, a second shifting mechanism 106, a third shaft system 107, a controller (not shown in the figure), and a differential assembly 109.

[0067] The first output shaft 1011 of the first drive motor 101 is coaxially connected to an output transmission component 1012. The output transmission component 1012 is connected to the first torque input end 1071 of the third shaft system 107. The third torque output end 1073 of the third shaft system 107 is connected to an input transmission component 1034. The input transmission component 1034 is coaxially arranged with the first shaft system 103 and can rotate relative to it.

[0068] The first shaft system 103's torque output end 1033 is connected to the differential assembly 109 in a transmission connection.

[0069] The first shift mechanism 104 can switch between a first neutral gear, a first gear, and a second gear. The first shift mechanism 104 is connected to the first shaft system 103. When the first shift mechanism 104 is in the first gear, the shaft system-second torque input end 1032 of the first shaft system 103 is connected to the input transmission component 1034. When the first shift mechanism 104 is in the second gear, the shaft system-first torque input end 1031 of the first shaft system 103 is connected to the first output shaft 1011 of the first drive motor 101.

[0070] The second shifting mechanism 106 is connected to the second output shaft 1021 of the second drive motor 102. The second shifting mechanism 106 has a neutral position, a third position, and a fourth position. When the second shifting mechanism 106 is in the third position, the second output shaft 1021 of the second drive motor 102 is connected to the first torque input end 1051 of the second shaft system 105. When the second shifting mechanism 106 is in the fourth position, the second output shaft 1021 of the second drive motor 102 is connected to the second torque input end 1052 of the second shaft system 105.

[0071] The first torque output end 1053 of the second shaft system 105 is connected to the second torque input end 1072 of the third shaft system 107. The second torque output end 1054 of the second shaft system 105 is connected to the differential assembly 109. The first torque input end 1051 of the second shaft system 105 is linked to the first torque output end 1053 of the second shaft system 105. The second torque input end 1052 of the second shaft system 105 is linked to the second torque output end 1054 of the second shaft system 105.

[0072] The controller is connected to both the first shifting mechanism 104 and the second shifting mechanism 106. When the controller controls the first drive motor 101 to shift gears, it simultaneously controls the second shifting mechanism 106 to be in the fourth gear position. When the controller controls the second drive motor 102 to shift gears, it simultaneously controls the first shifting mechanism 104 to be in the first gear position or the second gear position.

[0073] In the electric drive axle provided in this application embodiment, when the controller controls the first drive motor 101 to shift gears, it simultaneously controls the second shift mechanism 106 to be in the fourth gear. At this time, the second output shaft 1021 of the second drive motor 102 is connected to the second torque input end 1052 of the second shaft system 105, and the second torque output end 1054 of the second shaft system 105 is connected to the differential assembly 109. Power can be provided by the second drive motor 102 to ensure that the power is not interrupted during gear shifting. When the controller controls the second drive motor 102 to shift gears, it simultaneously controls the first shift mechanism 104 to be in either the first or second gear position. When the first shift mechanism 104 is in the first gear position, the shaft system 103's second torque input end 1032 is connected to the input transmission component 1034, and the input transmission component 1034 is connected to the output transmission component 1012, which is coaxially connected to the first output shaft 1011 of the first drive motor 101, via the third shaft system 107. At this time, the first drive motor 101 can provide power to ensure that the power is not interrupted during gear shifting. When the controller controls the first shift mechanism 104 to be in the second gear position, the shaft system 103's first torque input end 1031 is connected to the first output shaft 1011 of the first drive motor 101. At this time, the first drive motor 101 can provide power to ensure that the power is not interrupted during gear shifting.

[0074] Therefore, the electric drive axle provided in this application embodiment can ensure that the power is not interrupted during gear shifting, improve the smoothness of gear shifting, and thus improve the driving comfort of the vehicle.

[0075] Furthermore, since the first torque output end 1053 of the second shaft system 105 is connected to the first output shaft 1011 of the first drive motor 101 through the third shaft system 107, this application can disconnect the second output shaft 1021 of the second drive motor 102 from the first torque input end 1051 of the shaft system 105 by disengaging the third gear of the second shift mechanism 106, thereby disconnecting the transmission between the second drive motor 102 and the first drive motor 101. Both motors can operate independently and be completely disengaged, enabling coasting in neutral, reducing motor towing losses, improving system economy, and meeting the towing operation needs when the vehicle breaks down.

[0076] In some embodiments, the controller may include multiple control units to control the working states of the first shift mechanism 104 and the second shift mechanism 106, respectively.

[0077] It should be noted that the first drive motor 101 in the accompanying drawings provided in this application is denoted as EM1, and the second drive motor 102 is denoted as EM2.

[0078] It should be noted that, in practical applications, the first drive motor 101 and the second drive motor 102 described above can be either drive motors with the same output power or drive motors with different output power, depending on the actual vehicle design requirements. This application does not impose excessive limitations on the model and output power of the first drive motor 101 and the second drive motor 102 described above.

[0079] It should be noted that, in practical applications, the torque transmission process of the first output shaft 1011 of the first drive motor 101 includes:

[0080] When the first shifting mechanism 104 is in the first gear (i.e. Figure 1 When the left side of the first shift mechanism 104 is coupled, the second torque input end 1032 of the first shaft system 103 is connected to the input transmission component 1034. In this way, when the first output shaft 1011 of the first drive motor 101 rotates, it first drives the output transmission component 1012 to rotate on the same axis. The output transmission component 1012 then transmits the power to the first torque input end 1071 of the third shaft system 107. Then, the torque output end 1073 of the third shaft system 107 transmits the power to the input transmission component 1034. The input transmission component 1034 synchronously drives the second torque input end 1032 of the first shaft system 103 to rotate. Finally, the power is transmitted to the differential assembly 109 through the torque output end 1033 of the first shaft system 103.

[0081] When the first shift mechanism 104 is in the second gear (i.e. Figure 1 When coupled to the right side of the first shift mechanism 104, the first torque input end 1031 of the first shaft system 103 is connected to the first output shaft 1011 of the first drive motor 101; in this way, when the first output shaft 1011 of the first drive motor 101 rotates, it transmits power to the first torque input end 1031 of the first shaft system 103, and transmits power to the differential assembly 109 through the torque output end 1033 of the first shaft system 103.

[0082] The torque output end 1033 of the first shaft system 103 can directly transmit power to the differential assembly 109, or it can transmit power to the differential assembly 109 through the output shaft system 108.

[0083] It should be noted that in actual application scenarios, when the second shift mechanism 106 is in neutral, the third and fourth gears are both disengaged, and the output torque of the second output shaft 1021 of the second drive motor 102 cannot be transmitted to the first torque output end 1053 and the second torque output end 1054 of the second shaft system 105.

[0084] It should be noted that, in practical applications, the torque transmission process of the second output shaft 1021 of the second drive motor 102 includes:

[0085] When the second shift mechanism 106 is in the third gear (i.e. Figure 1 When the second shift mechanism 106 is coupled to the right side, the second output shaft 1021 of the second drive motor 102 is connected to the first torque input end 1051 of the second shaft system 105. In this way, when the second output shaft 1021 of the second drive motor 102 rotates, it can transmit power to the first torque input end 1051 of the second shaft system 105, and then the first torque output end 1053 of the second shaft system 105 transmits power to the second torque input end 1072 of the third shaft system 107, and then the third torque output end 1073 of the third shaft system 107 transmits power to the input transmission component 1034. At this time, when the first shift mechanism 104 is in the first gear, the input transmission component 1034 can synchronously drive the second torque input end 1032 of the first shaft system 103 to rotate, and finally the first torque output end 1033 of the first shaft system 103 transmits power to the differential assembly 109.

[0086] When the second shift mechanism 106 is in the fourth gear (i.e. Figure 1When the second shift mechanism 106 is coupled to the left side, the second output shaft 1021 of the second drive motor 102 is connected to the second torque input end 1052 of the second shaft system 105. In this way, when the second output shaft 1021 of the second drive motor 102 rotates, it can transmit power to the second torque input end 1052 of the second shaft system 105, and then the second torque output end 1054 of the second shaft system 105 transmits the power to the differential assembly 109.

[0087] The second torque output end 1054 of the second shaft system 105 can directly transmit power to the differential assembly 109, or it can transmit power to the differential assembly 109 through the output shaft system 108.

[0088] Furthermore, both the first drive motor 101 and the second drive motor 102 can independently output torque to the differential assembly 109 or through the output shaft system 108. Therefore, if either drive motor fails, the other drive motor can still output torque, which improves the operational reliability of the electric drive axle.

[0089] It should be noted that when the second shift mechanism 106 is in the third gear and the first shift mechanism 104 is in the first gear, the second output shaft 1021 of the second drive motor 102 can transmit power to the third shaft system 107 through the first torque input end 1051 and the first torque output end 1053 of the second shaft system 105; the first output shaft 1011 of the first drive motor 101 can transmit power to the third shaft system 107 through the output transmission component 1012; thus, the first drive motor 101 and the second drive motor 102 simultaneously transmit torque to the third shaft system 107, thereby ensuring that the output torque meets the requirements, reducing the energy consumption of a single motor, and increasing the total output torque of the vehicle.

[0090] like Figure 1 , Figure 2 , Figure 6 and Figure 7As shown, in some embodiments, the electric drive axle further includes an output shaft system 108. The second torque output terminal 1054 of the second shaft system 105 and the shaft-type torque output terminal 1033 of the first shaft system 103 are both drivenly connected to the differential assembly 109 via the output shaft system 108. In this way, the second torque output terminal 1054 of the second shaft system 105 and the shaft-type torque output terminal 1033 of the first shaft system 103 are both drivenly connected to the output shaft torque input terminal 1081 of the output shaft system 108, and the output shaft torque output terminal 1082 of the output shaft system 108 is drivenly connected to the differential assembly 109. This facilitates the layout of the second shaft system 105 and the first shaft system 103, and also facilitates the drive connection between the second torque output terminal 1054 of the second shaft system 105 and the shaft-type torque output terminal 1033 of the first shaft system 103 and the differential assembly 109. Figure 8 and Figure 9 As shown, in some other embodiments, the second torque output end 1054 of the second shaft system 105 and the shaft system-torque output end 1033 of the first shaft system 103 can also be directly connected to the transmission gear on the differential assembly 109, thereby reducing the number of parts and improving the structural compactness.

[0091] It should be noted that, in actual application scenarios, the first shaft system 103, the second shaft system 105, the third shaft system 107 and the output shaft system 108 mentioned above are all composed of transmission shafts, bearings and shaft-mounted parts (such as gears).

[0092] In some embodiments, the first drive motor 101, the second drive motor 102, the first shaft system 103, the first shift mechanism 104, the second shaft system 105, the second shift mechanism 106, the third shaft system 107, and the output shaft system 108 are arranged on the same side of the differential assembly 109, i.e., the electric drive axle housing. This application avoids occupying space on the other side of the electric drive axle housing and reduces the size of the electric drive axle by arranging the first drive motor 101, the second drive motor 102, the first shaft system 103, the first shift mechanism 104, the second shaft system 105, the second shift mechanism 106, the third shaft system 107, and the output shaft system 108 on the same side of the electric drive axle housing.

[0093] In some embodiments, the electric drive axle further includes a clutch 1074 and a torque amplifier 1075, which are configured together on the torque input end of the third shaft system 107 or the differential assembly 109 or on the transmission path between the differential assembly 109 and the drive half shaft of the wheel; wherein, the clutch 1074 is capable of switching the engagement and disengagement of the torque amplifier 1075 from the transmission path.

[0094] like Figure 2 and Figure 5As shown, in some embodiments, the clutch 1074 and the torque amplifier 1075 can be arranged as a set on the transmission path of the third shaft system 107. For example... Figure 7 and Figure 8 As shown, in some embodiments, the clutch 1074 and the torque amplifier 1075 may be arranged as a set on the drive path at the torque input end of the differential assembly 109. Figure 6 and Figure 9 As shown, in some embodiments, the clutch 1074 and torque amplifier 1075 can be arranged as a set on the transmission path between the differential assembly 109 and the drive half-shaft of the wheel. In certain operating conditions with high torque requirements, such as vehicle traction or steep slope climbing, in low gear (e.g., first gear), by integrating the torque amplifier 1075 into the transmission path, the wheel-end output torque can be increased for a short time, further enhancing the vehicle's traction and climbing capabilities.

[0095] In such Figure 2 and Figure 5 In the illustrated embodiment, the clutch 1074 and torque amplifier 1075 are assembled together on the transmission path of the third shaft system 107; wherein: the third shaft system 107 is divided into an input shaft segment and an output shaft segment; the torque input end of the torque amplifier 1075 is drivenly connected to the input shaft segment; the output end of the clutch 1074 is drivenly connected to the output shaft segment, and the input end of the clutch 1074 is switched to drively connect to the input shaft segment and the torque output end of the torque amplifier 1075; under the target operating condition, the controller controls the input end of the clutch 1074 to drively connect to the torque output end of the torque amplifier 1075. For example, the clutch is an electromagnetic clutch; the torque amplifier 1075 is a planetary gear mechanism, which achieves speed reduction and torque amplification through planetary transmission, and the torque amplification factor can be between 2 and 3. In addition to a planetary gear mechanism, the torque amplifier 1075 can also be a hydraulic torque converter, a worm gear reducer, etc.

[0096] The aforementioned target operating condition is for situations requiring high torque, such as vehicle extrication from difficult situations or climbing steep slopes. Further deceleration and torque increase are achieved by adding a torque amplifier 1075 to the third shaft system 107 after the power from the two motors converges. The engagement and disengagement of the torque amplifier 1075 from the output shaft section of the third shaft system 107 are controlled by the clutch 1074. Figure 5 As shown, when the left side of clutch 1074 is engaged, it is in normal output condition; when the right side of clutch 1074 is engaged, it is in torque amplification output condition. At this time, the power is input through the sun gear of the planetary gear mechanism, output through the planet carrier of the planetary gear mechanism, and finally transmitted to the torque output end 1073 of the third shaft system 107. The control of the above clutch 1074 can be selected by the driver according to the actual working conditions.

[0097] This application reduces torque attenuation by configuring a clutch 1074 and a torque amplifier 1075 in the third shaft system 107, thereby reducing the space occupied under the vehicle. For example, assuming that the single-motor output torque of the dual motors in the prior art and this solution is both 45... Therefore, the total output torque of the power output end in the existing technology is 90. Assuming that the transmission efficiency of each stage of the shaft in both the existing technology and this solution is 97%, and the torque amplifier 1075 increases torque by 20%, then the final torque T1 output to the wheel end by the existing technology is (90 × 97% × 97% × 97%) × 120% = 98.6. In this scheme, since the torque is directly received from the two drive motors by the torque amplifier 1075, the total torque input to the torque amplifier 1075 is T0 = (45 × 97%) + (45 × 97%) = 87.3. The final torque output to the wheel end, T2, is calculated as follows: T2 = 87.3 × 120% × 97% = 101.6. Clearly, this solution increases the final output torque and reduces torque decay.

[0098] In one possible implementation, the first shifting mechanism 104 described above includes:

[0099] First shift assembly 35 and second shift assembly 34;

[0100] The second shift assembly 34 selectively connects or disconnects the first output shaft 1011 of the first drive motor 101 and the first torque input terminal 1031 of the first shaft system 103. When the second shift assembly 34 connects the first output shaft 1011 of the first drive motor 101 and the first torque input terminal 1031 of the first shaft system 103, the first shift mechanism 104 is in the second gear position. At this time, the first output shaft 1011 of the first drive motor 101 directly transmits power to the first torque input terminal 1031 of the first shaft system 103.

[0101] The first shift assembly 35 selectively connects or disconnects the shaft system three torque output end 1073 of the third shaft system 107 and the shaft system one second torque input end 1032 of the first shaft system 103. When the first shift assembly 35 connects the shaft system three torque output end 1073 of the third shaft system 107 and the shaft system one second torque input end 1032 of the first shaft system 103, the first shift mechanism 104 is in the first gear. At this time, the first output shaft 1011 of the first drive motor 101 transmits power to the shaft system one second torque input end 1032 of the first shaft system 103 through the third shaft system 107.

[0102] It should be noted that in actual application scenarios, when both the first shift component 35 and the second shift component 34 are disconnected from their respective connected objects, the first shift mechanism 104 is in the first neutral gear position.

[0103] In one possible implementation, the second shifting mechanism 106 includes:

[0104] The third shift assembly 45, the sliding sleeve, and the fourth shift assembly 44; the sliding sleeve can be connected to the second output shaft 1021 of the second drive motor 102.

[0105] The fourth shift assembly 44 selectively connects or disconnects the second output shaft 1021 of the second drive motor 102 and the second torque input end 1052 of the second shaft system 105 via a sliding tooth sleeve.

[0106] The third shifting assembly 45 selectively connects or disconnects the second output shaft 1021 of the second drive motor 102 and the first torque input end 1051 of the second shaft system 105 via a sliding gear sleeve.

[0107] Those skilled in the art will understand that, in practical applications, the aforementioned first shift mechanism 104 and second shift mechanism 106 can be electronically controlled shift mechanisms, and the clutch 1074 can be an electronically controlled clutch. The shift signals and clutch control signals can be controlled by control signals issued by the engine control unit (ECU), hybrid control unit (HCU), vehicle control unit (VCU), or transmission control unit (TCU). This application only provides a mechanical structure for executing the corresponding logic and does not involve control methods.

[0108] It should be noted that in actual application scenarios, when the aforementioned sliding sleeve is not connected to either the third shift assembly 45 or the fourth shift assembly 44, the aforementioned second shift mechanism 106 is in neutral.

[0109] It should be noted that in practical application scenarios, by Figure 1 It can be seen that when the fourth shift assembly 44 is connected to the second output shaft 1021 of the second drive motor 102 and the second torque input end 1052 of the second shaft system 105 through the sliding gear sleeve transmission, the torque output by the second output shaft 1021 of the second drive motor 102 is directly transmitted to the output shaft system 108 through the second shaft system 105.

[0110] Depend on Figure 1It can be seen that when the third shift assembly 45 is connected to the second output shaft 1021 of the second drive motor 102 and the first torque input end 1051 of the second shaft system 105 via the sliding gear sleeve, the torque output by the second output shaft 1021 of the second drive motor 102 is transmitted to the third shaft system 107, and can be transmitted to the output shaft torque input end 1081 of the output shaft system 108 via the second torque input end 1032 of the first shaft system 103 when the first shift mechanism 104 is in the first gear.

[0111] In one possible implementation, the first shaft system 103 includes: a main shaft 31, a first transmission gear 33, and a gear sleeve 32.

[0112] The first transmission gear 33 is connected to the main shaft 31 for transmission. The first transmission gear 33 is the shaft system torque output end 1033 of the first shaft system 103.

[0113] The gear sleeve 32 is connected to the main shaft 31 for transmission. The first shift assembly 35 is selectively connected to or disconnected from the gear sleeve 32, and the second shift assembly 34 is selectively connected to or disconnected from the gear sleeve 32.

[0114] It should be noted that, in practical application scenarios, the structural schematic diagram of the first shaft system 103 described above is as follows: Figure 3 As shown, it includes a main shaft 31, a first transmission gear 33, and a gear sleeve 32, wherein the first transmission gear 33 is the shaft system-torque output end 1033 of the first shaft system 103. The second shift assembly 34 is connected to the first output shaft 1011 of the first drive motor 101, and the first shift assembly 35 is connected to a structure (such as a transmission gear) that is drivingly connected to the shaft system-second torque input end 1032 of the first shaft system 103.

[0115] In one possible implementation, the first output shaft 1011 of the first drive motor 101 is a hollow shaft, and the first output shaft 1011 of the first drive motor 101 is sleeved on the main shaft 31. This achieves a further reduction in structural volume while ensuring structural strength.

[0116] A schematic diagram of the second shaft system 105 is shown below. Figure 4 As shown, the system includes: an auxiliary shaft 41, a second transmission gear 42, and a transmission gear set 43. The second transmission gear 42 is the second torque output end 1054 of the second shaft system 105. The auxiliary shaft 41 is drive-connected to the fourth shift assembly 44. The transmission gear set 43 is rotatably mounted on the auxiliary shaft 41. The torque input end of the transmission gear set 43 is drive-connected to the third shift assembly 45, and the torque output end of the transmission gear set 43 is drive-connected to the first torque output end 1053 of the second shaft system 105. In one possible implementation, the first torque output end 1053 of the second shaft system 105 can also be the end gear of the torque output end of the transmission gear set 43.

[0117] In one possible implementation, the first shaft system 103, the second shaft system 105, and the third shaft system 107 are arranged in parallel.

[0118] In some embodiments, the second shifting mechanism 106 includes a first shifting part and a second shifting part, wherein the first shifting part is capable of switching between a second neutral gear and a third gear, and the second shifting part is capable of switching between a third neutral gear and a fourth gear;

[0119] The neutral gear includes a second neutral gear and a third neutral gear; when the first shifting part is in the third gear and the second shifting part is in the fourth gear, the first torque input end 1051 of the second shaft system 105 and the second torque input end 1052 of the second shaft system 105 are connected in a transmission manner.

[0120] The electric drive axle includes a dual-motor first-gear operating mode, a dual-motor second-gear operating mode, and a dual-motor third-gear operating mode. In the dual-motor first-gear operating mode, the controller controls the first shift mechanism 104 to be in the first gear and simultaneously controls the second shift mechanism 106 to be in the third gear. In the dual-motor second-gear operating mode, the controller controls the second shift mechanism 106 to be in both the third and fourth gears, and controls the first shift mechanism 104 to be in the first neutral gear. In the dual-motor third-gear operating mode, the controller controls the first shift mechanism 104 to be in the second gear and simultaneously controls the second shift mechanism 106 to be in the third gear.

[0121] Specifically, in this embodiment, the first shifting unit is composed of the aforementioned third shifting component 45 and a cooperating sliding sleeve; the second shifting unit is composed of the aforementioned fourth shifting component 44 and a cooperating sliding sleeve. In this way, the shifting of the first and second shifting units does not interfere with each other, allowing for independent gear switching and enabling diverse power transmission capabilities, making it better suited for different gear outputs. For example, the first shifting unit can be in the second neutral gear while the second shifting unit is in the third neutral gear; the first shifting unit can also be in the third gear, or the second shifting unit can be in the fourth gear; or the first shifting unit can be in the third gear while the second shifting unit is simultaneously in the fourth gear, in which case the first and second shifting units are connected by a transmission. It is understood that in other embodiments, the second shifting mechanism 106 can also switch between neutral, third gear, and fourth gear.

[0122] In this embodiment, the controller may include a first control unit, a second control unit, and a third control unit. The first control unit is connected to the first shifting mechanism 104 and is used to control the first shifting mechanism 104 to switch between a first neutral gear, a first gear, and a second gear. The second control unit is connected to the first shifting part and is used to control the first shifting part to switch between a second neutral gear and a third gear. The third control unit is connected to the second shifting part and is used to control the second shifting part to switch between a third neutral gear and a fourth gear.

[0123] The electric drive axle of this application embodiment has a three-speed dual-motor operation mode. The appropriate operating speed can be selected according to actual needs. In the dual-motor first-speed operation mode and the dual-motor third-speed operation mode, the power of the first drive motor 101 and the second drive motor 102 is converged on the first shaft system 103. In the dual-motor second-speed operation mode, the power of the first drive motor 101 and the second drive motor 102 is converged on the second shaft system 105. The power is transmitted to the differential assembly 109 through a single shaft, resulting in good transmission smoothness.

[0124] It should be noted that, in practical applications, the above target shifting strategy can be as shown in Table 1 below. Where A is the fourth gear; B is the first gear; C is the second gear; D is the third gear; and D... n It is a dual-motor operation mode, n∈(1,2,3), S Y It is a single-motor operation mode, Y∈(EM1,EM2), D a-b It is a dual-motor shifting mode. A checkmark indicates that the transmission is connected, and a blank space indicates that it is disconnected.

[0125] Table 1 Drive Mode Table

[0126]

[0127] Understandably, depending on actual operating conditions, the single-motor operation mode that occurs during gear shifting can also be used to provide power, thereby optimizing overall energy consumption.

[0128] In some embodiments, when switching from a dual-motor first-gear operation mode to a dual-motor second-gear operation mode, the controller first controls the second shifting mechanism 106 to exit the third gear position, placing the second shifting mechanism 106 in neutral, while keeping the first shifting mechanism 104 in the first gear position; then, it controls the second shifting mechanism 106 to the fourth gear position and raises the second drive motor 102 to gear 2; next, it controls the first shifting mechanism 104 to exit the first gear position, placing the first shifting mechanism 104 in first neutral, while keeping the second shifting mechanism 106 in the fourth gear position; finally, it controls the second shifting mechanism 106 to simultaneously be in the third gear position and raises the first drive motor 101 to gear 2.

[0129] When switching from the dual-motor two-speed operation mode to the dual-motor three-speed operation mode, the controller first controls the second shift mechanism 106 to exit the third gear while keeping the second shift mechanism 106 in the fourth gear; then controls the first shift mechanism 104 to be in the second gear and raises the first drive motor 101 to the third gear; then controls the second shift mechanism 106 to exit the fourth gear while keeping the first shift mechanism 104 in the second gear; finally, controls the second shift mechanism 106 to be in the third gear and raises the second drive motor 102 to the third gear.

[0130] As shown in Table 1 above:

[0131] In first gear, the first shifting mechanism 104 is in the first gear position and the second shifting mechanism 106 is in the third gear position. At this time, the speed ratios of the two motors are the same, and they both work in first gear, providing power to the vehicle together.

[0132] When shifting from 1st to 2nd gear, firstly, the second shift mechanism 106 is disengaged from the third gear position, and the second drive motor 102 (i.e., motor EM2) is in neutral. The first shift mechanism 104 remains in the first gear position. At this time, the first drive motor 101 (i.e., motor EM1) works independently in 1st gear, providing power to the vehicle. Then, the second shift mechanism 106 is shifted to the fourth gear position. At this time, both motors are running. Motor EM1 remains in the original 1st gear position, while motor EM2 shifts to 2nd gear. The two motors operate at different speeds, working together to provide power to the vehicle. Then, the first shift mechanism 104 is disengaged from the first gear position, and motor EM1 is in neutral. The second shift mechanism 106 remains in the fourth gear position. At this time, motor EM2 works independently in 2nd gear, providing power to the vehicle, ensuring uninterrupted power during gear shifting.

[0133] In second gear, the second shift mechanism 106 remains in the fourth gear position, while simultaneously shifting the second shift mechanism 106 to the third gear position. At this time, the two motors work together with the same speed ratio of 2, jointly providing power to the vehicle.

[0134] When shifting from 2nd to 3rd gear, firstly, the second shift mechanism 106 is disengaged from the third gear position, and motor EM1 is in neutral. The second shift mechanism 106 remains in the fourth gear position. At this time, motor EM2 operates independently in 2nd gear, providing power to the vehicle. Then, the first shift mechanism 104 is in the second gear position. Both motors operate simultaneously: motor EM2 remains in its original gear position, while motor EM1 shifts to 3rd gear. The two motors operate at different speeds, working together to provide power to the vehicle. Finally, the second shift mechanism 106 is disengaged from the fourth gear position, while the first shift mechanism 104 remains in the second gear position. At this time, motor EM1 operates independently in 3rd gear, providing power to the vehicle, ensuring uninterrupted power during gear shifting.

[0135] In 3rd gear, the first shift mechanism 104 remains in the second gear position, while the second shift mechanism 106 is in the third gear position. At this time, the two motors work together with the same speed ratio, both working in 3rd gear to provide power to the vehicle.

[0136] The electric drive axle architecture of this application embodiment has a single-motor operation mode and a dual-motor operation mode, and can also achieve uninterrupted power shifting by alternating operation of the two motors. In single-motor operation: the number of motors is selected based on the total power requirement. Because motor EM1 is closer to the wheel end (and has a higher overall efficiency and more gear ratio than motor EM2), if a single motor can meet the current power requirement of the entire vehicle, only motor EM1 needs to operate, and motor EM2 does not operate. In dual-motor operation, when the power requirement of a single motor does not meet the power requirement of the entire vehicle, both motors operate simultaneously.

[0137] The second aspect of this application provides a control method for an electric drive bridge, applied to an electric drive bridge as provided in the first aspect of this application and any implementation thereof. The control method for the electric drive bridge includes: controlling the first drive motor 101 to shift gears while simultaneously controlling the second shifting mechanism 106 to be in the fourth gear position; controlling the second drive motor 102 to shift gears while simultaneously controlling the first shifting mechanism 104 to be in the first gear position or the second gear position.

[0138] The control method for the electric drive axle provided in this application embodiment controls the first drive motor 101 to shift gears while simultaneously controlling the second shift mechanism 106 to be in the fourth gear position. At this time, the second output shaft 1021 of the second drive motor 102 is connected to the second torque input end 1052 of the second shaft system 105, and the second torque output end 1054 of the second shaft system 105 is connected to the differential assembly 109. Power can be provided by the second drive motor 102 to ensure that the power is not interrupted during gear shifting. When controlling the second drive motor 102 to shift gears, the first shift mechanism 104 is simultaneously controlled to be in either the first or second gear position. When the first shift mechanism 104 is in the first gear position, the shaft system 103's second torque input end 1032 is connected to the input transmission component 1034, and the input transmission component 1034 is connected to the output transmission component 1012, which is coaxially connected to the first output shaft 1011 of the first drive motor 101, via the third shaft system 107. At this time, the first drive motor 101 can provide power to ensure that the power is not interrupted during gear shifting. When controlling the first shift mechanism 104 to be in the second gear position, the shaft system 103's first torque input end 1031 is connected to the first output shaft 1011 of the first drive motor 101. At this time, the first drive motor 101 can provide power to ensure that the power is not interrupted during gear shifting.

[0139] Therefore, the control method for the electric drive axle provided in this application embodiment can ensure that the power is not interrupted during gear shifting, improve the smoothness of gear shifting, and thus improve the driving comfort of the vehicle.

[0140] Furthermore, since the first torque output end 1053 of the second shaft system 105 is connected to the first output shaft 1011 of the first drive motor 101 via the third shaft system 107, the control method of the electric drive axle provided in this embodiment can disconnect the third gear of the second shift mechanism 106 by controlling the disconnection of the second output shaft 1021 of the second drive motor 102 from the first torque input end 1051 of the shaft system 105, thereby disconnecting the transmission between the second drive motor 102 and the first drive motor 101. Both motors can operate independently and be completely disengaged, enabling coasting in neutral, reducing motor towing losses, improving system economy, and meeting the towing operation needs when the vehicle breaks down.

[0141] In some embodiments, the control method for the electric drive bridge includes:

[0142] When switching from the dual-motor first-gear operation mode to the dual-motor second-gear operation mode, firstly, the second shifting mechanism 106 is controlled to exit the third gear, so that the second shifting mechanism 106 is in neutral, while the first shifting mechanism 104 is kept in the first gear; then, the second shifting mechanism 106 is controlled to enter the fourth gear, and the second drive motor 102 is raised to the second gear; next, the first shifting mechanism 104 is controlled to exit the first gear, so that the first shifting mechanism 104 is in the first neutral, while the second shifting mechanism 106 is kept in the fourth gear; finally, the second shifting mechanism 106 is controlled to enter the third gear, and the first drive motor 101 is raised to the second gear.

[0143] When switching from the dual-motor two-speed operation mode to the dual-motor three-speed operation mode, firstly, the second shift mechanism 106 is controlled to exit the third gear while maintaining the second shift mechanism 106 in the fourth gear; then, the first shift mechanism 104 is controlled to be in the second gear, and the first drive motor 101 is raised to the third gear; next, the second shift mechanism 106 is controlled to exit the fourth gear while maintaining the first shift mechanism 104 in the second gear; finally, the second shift mechanism 106 is controlled to be in the third gear, and the second drive motor 102 is raised to the third gear.

[0144] As shown in Table 1 above:

[0145] In first gear, the first shifting mechanism 104 is in the first gear position and the second shifting mechanism 106 is in the third gear position. At this time, the speed ratios of the two motors are the same, and they both work in first gear, providing power to the vehicle together.

[0146] When shifting from 1st to 2nd gear, firstly, the second shift mechanism 106 is disengaged from the third gear position, and the second drive motor 102 (i.e., motor EM2) is in neutral. The first shift mechanism 104 remains in the first gear position. At this time, the first drive motor 101 (i.e., motor EM1) works independently in 1st gear, providing power to the vehicle. Then, the second shift mechanism 106 is shifted to the fourth gear position. At this time, both motors are running. Motor EM1 remains in the original 1st gear position, while motor EM2 shifts to 2nd gear. The two motors operate at different speeds, working together to provide power to the vehicle. Then, the first shift mechanism 104 is disengaged from the first gear position, and motor EM1 is in neutral. The second shift mechanism 106 remains in the fourth gear position. At this time, motor EM2 works independently in 2nd gear, providing power to the vehicle, ensuring uninterrupted power during gear shifting.

[0147] In second gear, the second shift mechanism 106 remains in the fourth gear position, while simultaneously shifting the second shift mechanism 106 to the third gear position. At this time, the two motors work together with the same speed ratio of 2, jointly providing power to the vehicle.

[0148] When shifting from 2nd to 3rd gear, firstly, the second shift mechanism 106 is disengaged from the third gear position, and motor EM1 is in neutral. The second shift mechanism 106 remains in the fourth gear position. At this time, motor EM2 operates independently in 2nd gear, providing power to the vehicle. Then, the first shift mechanism 104 is in the second gear position. Both motors operate simultaneously: motor EM2 remains in its original gear position, while motor EM1 shifts to 3rd gear. The two motors operate at different speeds, working together to provide power to the vehicle. Finally, the second shift mechanism 106 is disengaged from the fourth gear position, while the first shift mechanism 104 remains in the second gear position. At this time, motor EM1 operates independently in 3rd gear, providing power to the vehicle, ensuring uninterrupted power during gear shifting.

[0149] In 3rd gear, the first shift mechanism 104 remains in the second gear position, while the second shift mechanism 106 is in the third gear position. At this time, the two motors work together with the same speed ratio, both working in 3rd gear to provide power to the vehicle.

[0150] The control method for the electric drive axle in this embodiment operates as follows: In single-motor mode, the number of motors is selected based on the total power requirement. Because motor EM1 is closer to the wheel end (and has a higher overall efficiency due to the superior number of gears in each position compared to motor EM2), if a single motor can meet the current power requirement of the entire vehicle, only motor EM1 needs to operate, while motor EM2 remains inactive. In dual-motor mode, both motors operate simultaneously to prevent the power requirement of a single motor from failing to meet the overall vehicle power requirement.

[0151] In some embodiments, such as Figure 10 As shown, the electric drive axle is applied to a vehicle, and the control method for the electric drive axle includes:

[0152] S201. Obtain the total required torque T at the vehicle's wheel ends. req ;

[0153] Specifically, the total required torque is calculated based on the output speed and total required power under the target operating conditions; the output speed can be calculated based on the vehicle speed, as shown in the following formula.

[0154]

[0155]

[0156] In the formula, n 0 represents the output speed (motor speed), u represents the vehicle speed, i represents the speed ratio, r represents the wheel radius, and T represents the output speed. req P represents the total required torque, η represents the system efficiency of the electric drive axle, and is set according to requirements; req The total power demand can be calculated using the vehicle speed u.

[0157] S202. Set the output torque proportionality coefficient of the first drive motor 101 to β, and set the output torque proportionality coefficient of the second drive motor 102 to 1-β; select n random values ​​in the continuous value range [0,1] for β, and calculate the random output torque of the first drive motor 101 for each random value. and the random output torque of the second drive motor 102 ;

[0158] Discretize β from the interval [0,1] into n parts, and select the corresponding value for each part in sequence, such as 0, 0.1, 0.2, 0.3, 0.4, 0.5...0.9, 1; calculate the corresponding T for each part. EM1 and T EM2 Assuming that the initial motor torque distribution ratios are not abnormal, the number of n components can be sufficiently large to ensure a rich enough sample size, thereby improving the accuracy of the final determined motor torque distribution ratio.

[0159] S203, based on the random output torque T of the first drive motor 101 EM1 Obtain the random motor efficiency value of the first drive motor 101; based on the random output torque T of the second drive motor 102... EM2 Obtain the random motor efficiency value of the second drive motor 102;

[0160] Specifically, based on the efficiency characteristic diagrams of the first and second motors, from the corresponding T... EM1 and T EM2The corresponding random motor efficiency value is retrieved, and the motor efficiency values ​​under n different torque distribution ratios are calculated respectively. The efficiency characteristic diagrams of the first and second motors mentioned above are graphs characterizing the ratio of output mechanical power to input electrical power of the motor under different operating conditions, which can be obtained by performing calibration tests on the first and second drive motors respectively.

[0161] S204. Calculate the random total efficiency value of the dual motors after superimposing the random motor efficiency values ​​of the first drive motor 101 and the second drive motor 102 under each random value. Select the random value corresponding to the largest random total efficiency value of the dual motors as the target value of the output torque proportional coefficient β of the first drive motor 101.

[0162] The optimal motor torque distribution ratio, which yields the highest efficiency under the current operating conditions, is selected as the optimal motor torque distribution. This achieves energy-efficient torque allocation between motors EM1 and EM2, ensuring they operate fully within their high-efficiency range, avoiding energy waste, and minimizing energy consumption. This torque distribution control method is applicable to both dual-motor and single-motor operating modes, enabling the lowest-energy-consumption torque distribution among the two motors.

[0163] It should be noted that the control method in this embodiment is achieved by obtaining vehicle parameter sets for each working condition. The vehicle parameter sets include at least: wheel end torque demand under the working condition, vehicle speed, efficiency characteristic diagram of the first motor of the first drive motor 101, efficiency characteristic diagram of the second motor of the second drive motor 102, and transmission system parameters of the electric drive axle.

[0164] Based on the transmission system parameters in the vehicle parameter set for the target working condition, the wheel end required torque in the vehicle parameter set for the target working condition is converted into the total required torque at the motor shaft end, and the vehicle speed in the vehicle parameter set for the target working condition is converted into the output speed at the motor shaft end. The target working condition is any one of the working conditions.

[0165] In some embodiments, such as Figure 11 As shown, the electric drive axle is applied to a vehicle, and the control method includes:

[0166] S301. Select different pedal openings of the vehicle, and under each pedal opening, plot the drive motor efficiency curve of each gear as a function of the vehicle speed.

[0167] The pedal opening range is 0-100%, and different pedal deployment distances (m) can be selected to choose different pedal openings.

[0168] Taking first gear as an example, this explains how to obtain the vehicle speed versus motor efficiency curve:

[0169] Given the motor efficiency curve (speed-torque-efficiency) and the motor operating condition curves (pedal opening-motor speed-motor torque) for different pedal openings, with a fixed gear ratio for first gear, the motor torque point corresponding to each motor speed at different pedal openings can be obtained by referring to the motor operating condition curves for different pedal openings. The vehicle speed is calculated as follows:

[0170]

[0171] In the formula, n0 is the motor speed, u is the vehicle speed, i is the speed ratio, and r is the wheel radius.

[0172] Given the vehicle speed (which can be calculated from the motor speed) and motor torque, the motor efficiency at the current operating point can be obtained by referring to the motor efficiency curve. Matching the obtained vehicle speed and motor efficiency yields the "vehicle speed - motor efficiency" curve for each pedal opening in first gear. The "vehicle speed - motor efficiency" curves for each pedal opening in second and third gears are obtained in the same way.

[0173] S302. At each pedal opening, the vehicle speed corresponding to the intersection point of the two drive motor efficiency curves of two adjacent gears is selected as the target shift speed at that pedal opening.

[0174] For the efficiency curves of the same pedal opening: superimpose the efficiency curves of the two gears adjacent to the target gear to determine the efficiency intersection point of the target gear. The vehicle speed corresponding to the efficiency intersection point is the critical point where the motor efficiencies of the first drive motor and the second drive motor of the two gears adjacent to the target gear are equal.

[0175] S303. Connect the target shift speeds obtained at different pedal openings to plot different gear shift curves with pedal opening and vehicle speed as the coordinate axes, such as... Figure 12 As shown;

[0176] According to the order of vehicle speed corresponding to the efficiency intersection point from low to high, the efficiency intersection points corresponding to each pedal opening are connected in sequence at each of the two adjacent gear positions to obtain the gear shifting curves of different gear positions as the optimal shifting curves for energy consumption.

[0177] S304. Based on the vehicle's real-time pedal opening and shifting requirements, obtain the real-time target shifting speed through different gear shifting curves, and execute the target shifting operation of the drive motor at the real-time target shifting speed; wherein, the drive motor is the first drive motor 101 and / or the second drive motor 102; the shifting requirements include shifting between first and second gear and shifting between second and third gear, and the specific shifting requirements are determined according to the gear position of the motor. For example, when the motor is in first gear, its shifting requirement is to shift up to second gear; when the motor is in second gear, its shifting requirement is to shift down to first gear or shift up to third gear; when the motor is in third gear, its shifting requirement is to shift down to second gear.

[0178] The control method provided in this embodiment is based on the principle of minimizing motor energy consumption and proposes an optimal shifting strategy to improve the overall vehicle economy. Under different pedal openings, the drive motor exhibits an efficiency curve as vehicle speed changes. The efficiency curves of two adjacent gears intersect at a point; connecting these intersections yields the economical shifting curve. Both single-motor and dual-motor operating conditions employ the economical shifting strategy, shifting gears based on minimizing drive motor energy consumption while ensuring overall vehicle power performance. By selecting and switching between optimal energy consumption modes, the motor operates fully within its high-efficiency range, avoiding energy waste.

[0179] In practical applications, the aforementioned optimal energy-saving shift curve represents the gear that best matches the pedal opening and corresponding vehicle speed under the condition of lowest energy consumption during shifting. Since the current pedal opening and current vehicle speed are key factors for shifting, excessive acceleration or excessively low speed will not only increase energy consumption during shifting but also increase the risk of shift failure. Figure 12 The diagram illustrates the optimal shift curves for energy efficiency. The dashed lines represent the optimal shift curves for downshifting, and the solid lines represent the optimal shift curves for upshifting. Generally, the target shift speed for downshifting is drawn by reducing the target shift speed for upshifting by an appropriate amount. Specifically, 601 is the optimal shift curve for shifting from 2nd to 1st gear, 602 is for shifting from 1st to 2nd gear, 603 is for shifting from 3rd to 2nd gear, and 604 is for shifting from 2nd to 3rd gear. When the point corresponding to the current pedal opening and current speed falls within any of these optimal shift curves, the gear corresponding to that curve is determined as the target gear. Furthermore, when this point is within an optimal shift curve, the subsequent shift to the target gear must be executed immediately. For example, if the point corresponding to the current pedal opening and current speed falls within 604, the target gear is third gear.

[0180] It should be noted that this application, by configuring the dual-motor operation mode, finds the target gear that is compatible with the current pedal opening and the current vehicle speed in the optimal energy consumption shift curve, thereby reducing energy loss during the shifting process and improving the energy utilization rate of the electric drive axle.

[0181] It should be noted that, in practical applications, the aforementioned target shifting strategy includes shifting strategies corresponding to various combinations of the first and second shifting mechanisms, such as dual-motor first gear, dual-motor first-to-second gear shift, dual-motor second gear, dual-motor second-to-third gear shift, dual-motor third gear, and corresponding downshifting strategies. This target shifting strategy can be pre-stored in the controller of the electric drive axle. The types of controllers include, but are not limited to, engine control units (ECUs), hybrid control units (HCUs), vehicle control units (VCUs), or transmission control units (TCUs).

[0182] This application reduces energy consumption during gear shifting by configuring a target gear in a dual-motor operation mode that matches both the current pedal opening and the current vehicle speed within an optimal energy-consumption shift curve. Furthermore, by configuring a preset motor torque distribution ratio corresponding to the current wheel-end torque demand, the compatibility of the current motor torque distribution ratio with the current operating conditions of the pure electric heavy-duty truck is improved, further reducing energy consumption. Finally, by configuring a target shifting strategy based on the target gear, the target shifting mechanism selectively connects or disconnects the output shaft of the target drive motor and the torque input end of the target shaft system, and controls the first drive motor and / or the second drive motor to operate based on the current motor torque distribution ratio. Here, the target shifting mechanism is the first shifting mechanism and / or the second shifting mechanism, the target drive motor is the first drive motor and / or the second drive motor, and the target shaft system is the first shaft system, the second shaft system, and / or the third shaft system. This ensures that one of the first or second drive motors continuously outputs power during the shifting process of the other drive motor, avoiding power interruption. Therefore, this application improves the compatibility of the electric drive axle with the operating conditions of the pure electric heavy-duty truck.

[0183] It should be noted that in practical applications, for electric drive axles, the transmission paths of the output torque of the first and second drive motors differ at different gears, resulting in variations in the transmission ratios. Consequently, at different pedal openings, the output torque of the motor differs significantly from the actual torque transmitted to the output shaft system, leading to substantial fluctuations in energy consumption. Therefore, this application determines the motor efficiency versus speed at each gear based on the transmission ratios of each gear, the efficiency characteristic diagrams of the first and second motors, thereby enabling the determination of motor efficiency under different operating conditions.

[0184] It should be noted that, in practical application scenarios, this application determines the efficiency intersection point of the target gear by superimposing the efficiency curves of the two gears adjacent to the target gear through configuration. The vehicle speed corresponding to the efficiency intersection point is the critical point where the motor efficiencies of the first drive motor and the second drive motor of the two gears adjacent to the target gear are equal. This enables the determination of the shifting critical point with the lowest energy consumption, thereby ensuring that the shifting process and the motors before and after it maintain high efficiency operation, and achieving the goal of reducing energy consumption while increasing output torque.

[0185] In some embodiments, the electric drive axle further includes a clutch 1074 and a torque amplifier 1075, which are configured together on the torque input end of the third shaft system 107 or the differential assembly 109 or on the transmission path between the differential assembly 109 and the drive half shaft of the wheel; wherein, the clutch 1074 is capable of switching the engagement and disengagement of the torque amplifier 1075 from the transmission path.

[0186] The control method for the electric drive axle includes controlling the input end of the clutch 1074 to drive the torque output end of the torque amplifier 1075 under the target operating condition.

[0187] The aforementioned target operating conditions are those requiring high torque, such as vehicle extrication from difficult situations or climbing steep slopes. The engagement and disengagement of the torque amplifier and the output shaft segment of the third shaft system 107 are achieved by controlling the clutch. Figure 5 As shown, when the left side of the clutch is engaged, it is the normal output condition; when the right side of the clutch is engaged, it is the torque amplification output condition. At this time, the power is input through the sun gear of the planetary gear mechanism, output through the planet carrier of the planetary gear mechanism, and finally transmitted to the torque output end 1073 of the third shaft 107. The above clutch control can be selected by the driver according to the actual working conditions.

[0188] This application also provides a vehicle, including an electric drive axle provided by the first aspect of this application and any implementation thereof.

[0189] It should also be noted that the device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. In addition, in the device embodiment drawings provided in this application, the connection relationship between modules indicates that they have a communication connection, which can be implemented as one or more communication buses or signal lines.

[0190] Through the above description of the embodiments, those skilled in the art can clearly understand that this application can be implemented by means of software plus necessary general-purpose hardware, or it can be implemented by special-purpose hardware including application-specific integrated circuits, special-purpose CPUs, special-purpose memory, special-purpose components, etc. Generally, any function performed by a computer program can be easily implemented by corresponding hardware, and the specific hardware structure used to implement the same function can also be diverse, such as analog circuits, digital circuits, or special-purpose circuits. However, for this application, software program implementation is more often the preferred implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a readable storage medium, such as a computer floppy disk, USB flash drive, mobile hard disk, ROM, RAM, magnetic disk, or optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, training equipment, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0191] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product.

Claims

1. An electric drive bridge, characterized in that, include: First drive motor (101), second drive motor (102), first shaft system (103), first shift mechanism (104), second shaft system (105), second shift mechanism (106), third shaft system (107), controller and differential assembly (109). The first output shaft (1011) of the first drive motor (101) is coaxially connected to an output transmission component (1012), the output transmission component (1012) is connected to the first torque input end (1071) of the third shaft system (107), the third torque output end (1073) of the third shaft system (107) is connected to an input transmission component (1034), the input transmission component (1034) is coaxially arranged with the first shaft system (103) and can rotate relative to it; The first shaft system (103) has a torque output end (1033) that is connected to the differential assembly (109) in a transmission connection; The first shift mechanism (104) is capable of switching between a first neutral gear, a first gear, and a second gear. The first shift mechanism (104) is connected to the first shaft system (103). When the first shift mechanism (104) is in the first gear, the shaft system-second torque input end (1032) of the first shaft system (103) is connected to the input transmission component (1034). When the first shift mechanism (104) is in the second gear, the shaft system-first torque input end (1031) of the first shaft system (103) is connected to the first output shaft (1011) of the first drive motor (101). The second shift mechanism (106) is connected to the second output shaft (1021) of the second drive motor (102); the second shift mechanism (106) has a neutral gear, a third gear and a fourth gear. When the second shift mechanism (106) is in the third gear, the second output shaft (1021) of the second drive motor (102) is driven to the first torque input end (1051) of the second shaft system (105); when the second shift mechanism (106) is in the fourth gear, the second output shaft (1021) of the second drive motor (102) is driven to the second torque input end (1052) of the second shaft system (105). The first torque output end (1053) of the second shaft system (105) is driven to the second torque input end (1072) of the third shaft system (107), the second torque output end (1054) of the second shaft system (105) is driven to the differential assembly (109), the first torque input end (1051) of the second shaft system (105) is linked to the first torque output end (1053) of the second shaft system (105), and the second torque input end (1052) of the second shaft system (105) is linked to the second torque output end (1054) of the second shaft system (105). The controller is connected to both the first shifting mechanism (104) and the second shifting mechanism (106). When the controller controls the first drive motor (101) to shift gears, it simultaneously controls the second shifting mechanism (106) to be in the fourth gear position. When the controller controls the second drive motor (102) to shift gears, it simultaneously controls the first shifting mechanism (104) to be in the first gear position or the second gear position.

2. The electric drive bridge according to claim 1, characterized in that, It also includes a clutch (1074) and a torque amplifier (1075), which are set together at the torque input end of the third shaft system (107) or the differential assembly (109) or on the transmission path of the differential assembly (109) and the drive half shaft of the wheel; wherein, the clutch (1074) can switch the engagement and disengagement of the torque amplifier (1075) and the transmission path.

3. The electric drive bridge according to claim 2, characterized in that, The clutch (1074) and the torque amplifier (1075) are assembled together on the transmission path of the third shaft system (107); wherein: The third shaft system (107) is divided into an input shaft segment and an output shaft segment; The torque input terminal of the torque amplifier (1075) is connected to the input shaft segment via a transmission. The output end of the clutch (1074) is connected to the output shaft segment, and the input end of the clutch (1074) is connected to the input shaft segment and the torque output end of the torque amplifier (1075) in a switching transmission connection. When the controller is in the target operating condition, it controls the input end of the clutch (1074) to be connected to the torque output end of the torque amplifier (1075) for transmission.

4. The electric drive bridge according to claim 1, characterized in that, The second shifting mechanism (106) includes a first shifting part and a second shifting part. The first shifting part can switch between a second neutral gear and the third gear, and the second shifting part can switch between a third neutral gear and the fourth gear. The neutral gear position includes the second neutral gear position and the third neutral gear position; when the first shifting part is in the third gear position and the second shifting part is in the fourth gear position, the first torque input end (1051) of the second shaft system (105) is connected to the second torque input end (1052) of the second shaft system (105) in a transmission connection; The electric drive axle includes a dual-motor first-gear operation mode, a dual-motor second-gear operation mode, and a dual-motor third-gear operation mode. In the dual-motor first-gear operation mode, the controller controls the first shifting mechanism (104) to be in the first gear, and simultaneously controls the second shifting mechanism (106) to be in the third gear. In the dual-motor second-gear operation mode, the controller controls the second shifting mechanism (106) to be in both the third and fourth gears, and controls the first shifting mechanism (104) to be in the first neutral gear. In the dual-motor third-gear operation mode, the controller controls the first shifting mechanism (104) to be in the second gear, and simultaneously controls the second shifting mechanism (106) to be in the third gear.

5. The electric drive bridge according to claim 4, characterized in that, When switching from the dual-motor first-gear operation mode to the dual-motor second-gear operation mode, the controller first controls the second shifting mechanism (106) to exit the third gear, so that the second shifting mechanism (106) is in the neutral gear, while keeping the first shifting mechanism (104) in the first gear; then controls the second shifting mechanism (106) to be in the fourth gear, and raises the second drive motor (102) to gear 2; then controls the first shifting mechanism (104) to exit the first gear, so that the first shifting mechanism (104) is in the first neutral gear, while keeping the second shifting mechanism (106) in the fourth gear; finally controls the second shifting mechanism (106) to be in the third gear, and raises the first drive motor (101) to gear 2. When switching from the dual-motor two-speed operation mode to the dual-motor three-speed operation mode, the controller first controls the second shift mechanism (106) to exit the third gear while keeping the second shift mechanism (106) in the fourth gear; then controls the first shift mechanism (104) to be in the second gear and raises the first drive motor (101) to the third gear; then controls the second shift mechanism (106) to exit the fourth gear while keeping the first shift mechanism (104) in the second gear; finally controls the second shift mechanism (106) to be in the third gear and raises the second drive motor (102) to the third gear.

6. The electric drive axle according to any one of claims 1-5, characterized in that, It also includes an output shaft system (108), the second torque output end (1054) of the second shaft system (105) and the shaft system-torque output end (1033) of the first shaft system (103) are all connected to the differential assembly (109) through the output shaft system (108).

7. The electric drive axle according to claim 6, characterized in that, The first drive motor (101), the second drive motor (102), the first shaft system (103), the first shift mechanism (104), the second shaft system (105), the second shift mechanism (106), the third shaft system (107), and the output shaft system (108) are arranged on the same side of the differential assembly (109).

8. A control method for an electric drive bridge, characterized in that, The electric drive axle applied to any one of claims 1 to 7, wherein the control method of the electric drive axle includes: controlling the first drive motor (101) to shift gears while simultaneously controlling the second shifting mechanism (106) to be in the fourth gear position; controlling the second drive motor (102) to shift gears while simultaneously controlling the first shifting mechanism (104) to be in the first gear position or the second gear position.

9. The control method for the electric drive bridge according to claim 8, characterized in that, include: When switching from dual-motor first-gear operation mode to dual-motor second-gear operation mode, firstly, the second shifting mechanism (106) is controlled to exit the third gear position, so that the second shifting mechanism (106) is in the neutral gear position, while the first shifting mechanism (104) is kept in the first gear position; then, the second shifting mechanism (106) is controlled to enter the fourth gear position, and the second drive motor (102) is raised to the second gear; then, the first shifting mechanism (104) is controlled to exit the first gear position, so that the first shifting mechanism (104) is in the first neutral gear position, while the second shifting mechanism (106) is kept in the fourth gear position; finally, the second shifting mechanism (106) is controlled to enter the third gear position, and the first drive motor (101) is raised to the second gear. When switching from the dual-motor two-speed operation mode to the dual-motor three-speed operation mode, firstly, the second shift mechanism (106) is controlled to exit the third gear position, while the second shift mechanism (106) is kept in the fourth gear position; then, the first shift mechanism (104) is controlled to be in the second gear position, and the first drive motor (101) is raised to the third gear; then, the second shift mechanism (106) is controlled to exit the fourth gear position, while the first shift mechanism (104) is kept in the second gear position; finally, the second shift mechanism (106) is controlled to be in the third gear position, and the second drive motor (102) is raised to the third gear.

10. The control method for the electric drive bridge according to claim 8, characterized in that, The electric drive axle is applied to a vehicle, and the control method includes: Obtain the total required torque T at the vehicle wheel ends req ; The output torque proportionality coefficient of the first drive motor (101) is set to β, and the output torque proportionality coefficient of the second drive motor (102) is set to 1-β. β is then selected from n random values ​​within the continuous range [0,1], and the random output torque of the first drive motor (101) is calculated for each random value. and the random output torque of the second drive motor (102) ; According to the random output torque T of the first drive motor (101) EM1 Obtain the random motor efficiency value of the first drive motor (101); based on the random output torque T of the second drive motor (102)... EM2 Obtain the random motor efficiency value of the second drive motor (102); Calculate the random total efficiency value of the dual motors after superimposing the random motor efficiency value of the first drive motor (101) and the random motor efficiency value of the second drive motor (102) under each random value, and select the random value corresponding to the largest random total efficiency value of the dual motors as the target value of the output torque proportional coefficient β of the first drive motor (101).

11. The control method for the electric drive bridge according to claim 8, characterized in that, The electric drive axle is applied to a vehicle, and the control method includes: Select different pedal openings for the vehicle, and at each pedal opening, plot the drive motor efficiency curve for each gear as a function of the vehicle speed. At each pedal opening, the vehicle speed corresponding to the intersection point of the two drive motor efficiency curves of two adjacent gears is selected as the target shift speed at that pedal opening. Connect the target shift speeds obtained at different pedal openings and plot them as different gear shift curves with pedal opening and vehicle speed as coordinate axes. Based on the vehicle's real-time pedal opening and shifting requirements, the real-time target shifting speed is obtained through the different gear shifting curves, and the target shifting operation of the drive motor is executed at the real-time target shifting speed. The drive motor is the first drive motor (101) and / or the second drive motor (102); the shifting requirements include shifting between first and second gears and shifting between second and third gears.

12. The control method for the electric drive bridge according to claim 8, characterized in that, The electric drive axle also includes a clutch (1074) and a torque amplifier (1075), which are configured together on the torque input end of the third shaft system (107) or the differential assembly (109) or on the transmission path of the differential assembly (109) and the drive half shaft of the wheel; wherein, the clutch (1074) can switch the engagement and disengagement of the torque amplifier (1075) from the transmission path; The control method includes: Under the target operating condition, the input end of the clutch (1074) is connected to the torque output end of the torque amplifier (1075) in a transmission connection.

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