Electric drive axle system of pure electric vehicle

Abstract

The electric drive axle system of the pure electric vehicle comprises a middle axle and a rear axle, and the middle axle is of a double-motor double-gearbox non-power-interruption structure; the rear axle adopts a single-motor and single-gearbox structure; the electric drive axle system of the pure electric vehicle further comprises three TCU controllers, wherein a TCU controller and a total TCU controller are independently arranged on the middle axle and the rear axle respectively. According to the electric drive axle system of the pure electric vehicle, each axle is an independent power control unit, even if one axle breaks down and cannot output power, the other axle cannot be affected, and the problems that the whole vehicle lies down, power is lost, and driving cannot be conducted are solved; the middle axle of the system is a system without power interruption, the torque proportion of the two motors can be adjusted according to the current whole vehicle torque requirement, the running rotating speed and the torque working point of the motors can be adjusted, and the system efficiency is optimized.

Description

Technical Field

[0001] The present invention relates to the technical field of electric drive axles, and in particular to an electric drive axle system for a pure electric vehicle. Background Art

[0002] According to the 2025 new energy commercial vehicle product layout of domestic first-class OEMs, the markets such as logistics below 18T, municipal sanitation, and 49T traction will gradually withdraw from the centrally arranged AMT drive route and adopt the electric drive axle route. Electric drive axle products will become an important part of the new energy power system in the future.

[0003] A series of policies and regulations support the development of new energy commercial vehicles in terms of purchase and use. Driven by policies and the development trend of industry technology, the competitiveness of new energy commercial vehicles in the market will gradually increase, especially in first- and second-tier cities with increasingly stringent environmental protection policies. Municipal sanitation and medium- and short-distance logistics pure electric commercial vehicles matching electric drive axle products will be greatly developed. However, many electric drive axle technologies currently still use single-motor single-bridge or dual-motor technologies. Some of these technologies are single-bridge and cannot achieve multi-power source drive problems, and some have gear shift interruptions and cannot achieve smooth gear shifting and no power interruption problems when shifting. Therefore, there is an urgent need to realize a new technology that can drive multiple power sources and achieve gear shifting without power interruption. Summary of the invention

[0004] In view of the deficiencies in the prior art, the purpose of the present invention is to provide an electric drive axle system for a pure electric vehicle to solve the problems that the electric drive axle technology in the prior art cannot achieve multi-power source drive and cannot achieve smooth gear shifting and gear shifting without power interruption.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions to achieve the above problems: a pure electric vehicle electric drive axle system, including a middle axle and a rear axle, the middle axle adopts a non-powered interruption structure of dual motors and dual gearboxes, and the rear axle adopts a single motor and single gearbox structure.

[0006] The present invention also has the following technical features:

[0007] A TCU controller is independently installed on the middle bridge and the rear bridge, and the TCU controllers on the middle bridge and the rear bridge are respectively connected to the main TCU controller.

[0008] The dual gearbox is equipped with two independent output shaft speed sensors; the single gearbox is equipped with one output shaft speed sensor.

[0009] The double gearbox and the single gearbox both adopt two-speed gearboxes.

[0010] The dual motors and the single motor both use high-speed motors with a maximum speed of 12000 rpm.

[0011] Compared with the prior art, the present invention has the following technical effects:

[0012] (I) The electric drive axle system for a pure electric vehicle provided by the present invention has two axles, each of which is an independent power control unit. Even if one axle has a gear shifting problem, a motor problem, or any other problem, which causes the axle to be unable to output power, the other axle will not be affected and will not cause the entire vehicle to stall, lose power, or be unable to drive. At least one of the three gearboxes in the system must be in gear in real time, so that power is not interrupted and there is no power loss.

[0013] (II) The electric drive axle system of the pure electric vehicle provided by the present invention has a key power-on and power-off counting function in the first total TCU, and sends this count in the form of a message to the TCU on each subsequent axle to ensure that the power-on counts in the three TCUs are consistent. This count is a cyclic mode, with six times as a cycle. In each cycle, the system has six modes. If there is no key power-on and power-off counting, in each mode, a fixed gearbox will be working each time, and the other will not work for a long time. This will cause the gearbox that has been working for a long time to be seriously worn, while the gearbox that has not been working for a long time will hardly be worn, which will lead to To ensure the uniform usage of the three gearboxes and the life of the gears of each gearbox, the whole system uses the key power-on and power-off counting function, and each mode corresponds to different gears of the three gearboxes. The six modes in each counting cycle can be calibrated in real time according to different working conditions and different OEM requirements. It is very flexible and has a wide range of applicability. The system's mid-bridge is a system without power interruption. The two motors are independently controlled. When maintaining a certain working mode, the torque ratio of the two motors can be adjusted according to the torque demand of the whole vehicle at that time. The speed and torque working point of the motor can be adjusted to optimize the system efficiency.

[0014] (II) The electric drive axle system of a pure electric vehicle provided by the present invention has a simple structure, is easy to install, easy to operate, safe and reliable, and has strong adaptability, and can well solve the existing problems. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the overall structure of the electric drive axle system of a pure electric vehicle of the present invention.

[0016] Figure 2 It is a schematic diagram of the middle bridge structure of the present invention.

[0017] The meaning of each symbol in the accompanying drawings:

[0018] 1-middle axle, 2-rear axle.

[0019] The specific contents of the present invention are further explained in detail below in conjunction with embodiments. DETAILED DESCRIPTION

[0020] All components in the present invention, unless otherwise specified, are components known in the prior art.

[0021] Specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent changes made on the basis of the technical solution of this application fall within the protection scope of the present invention.

[0022] Embodiment 1:

[0023] This embodiment provides a pure electric vehicle electric drive axle system, such as Figure 1-Figure 2 As shown, it includes a middle bridge 1 and a rear bridge 2, wherein the middle bridge 1 adopts a dual-motor dual-gearbox non-power interruption structure;

[0024] The rear axle 2 adopts a single motor and a single gearbox structure;

[0025] The dual-motor dual-gearbox structure has two motors connected to the gearbox respectively, and then the gearbox is connected to the mid-axle differential. The single-motor, single-gearbox structure has a single motor connected to the gearbox and then connected to the rear axle differential.

[0026] The electric drive axle system of the pure electric vehicle also includes three TCU controllers (automatic transmission control units, wherein each of the middle axle 1 and the rear axle 2 has an independent TCU controller and a master TCU controller, and the master TCU controller is connected to the TCU controllers on the middle axle 1 and the rear axle 2 respectively.

[0027] The front and rear axle gearbox ratios are 6.6:1 and 50.41:1.

[0028] The electric drive axle system of a pure electric vehicle provided in this embodiment adopts an independent double-bridge structure, and is composed of three motors and three gearboxes in total. The middle bridge adopts a dual-motor and dual-gearbox structure without power interruption, and the rear axle adopts a single-motor and single-gearbox structure. The two power systems are both independent and coupled.

[0029] Each gearbox is a two-speed gearbox, and each motor is a high-speed motor with a maximum speed of 12000rpm. The gearbox uses a pneumatic mechanism and a sliding sleeve to combine and control gear shifting. In this system, there are three TCU controllers, one of which is used as the overall mode and the target mode for each bridge. The remaining two bridges each have an independent TCU controller. The TCU controller on each bridge accepts the target mode of the first TCU controller, and then splits it into the target gear position of each gearbox on the independent bridge, and then controls each gearbox for gear shifting control. The TCU on each bridge is an independent power control unit, which independently handles throttle torque and energy recovery, and finally performs torque limit protection on each bridge according to the maximum torque of each bridge. This makes each bridge an independent power control unit. The force control unit will not affect the other bridge even if one bridge fails to output power due to problems such as gear shifting, motor problems, or other problems. The whole vehicle will not break down, lose power, or become inoperable. Moreover, each bridge is independent, and the middle bridge can achieve gear shifting without power interruption and with little power loss during the driving process. The target mode of each bridge can be made according to the high-efficiency zone of each motor and the working conditions, so that the total driving mode is varied. Only the middle bridge, the rear axle, or both bridges can participate in the driving. When the middle bridge participates in the driving, there are various power modes, such as only one gearbox participating or both gearboxes participating. This ensures that the whole vehicle always runs in the high-efficiency zone of the motor, minimizing the power consumption of the whole vehicle.

[0030] As a preferred embodiment of this invention:

[0031] An output shaft speed sensor is installed on each of the three gearboxes on the middle bridge 1 and the rear bridge 2.

[0032] As a preferred embodiment of this invention:

[0033] The three gearboxes on the middle bridge 1 and the rear bridge 2 are all two-speed gearboxes.

[0034] The motors on the middle bridge 1 and the rear bridge 2 are both high-speed motors with a maximum speed of 12000 rpm.

[0035] The specific usage method of this embodiment is as follows:

[0036] Table 1 System operating mode at the first power-on

[0037]

[0038] Table 2 System working mode for the second power-on

[0039]

[0040]

[0041] Table 3 System working mode at the third power-on

[0042]

[0043] Table 4 System working mode at the fourth power-on

[0044]

[0045] Table 5 System working mode at the fifth power-on

[0046]

[0047] Table 6 System working mode at the sixth power-on

[0048]

[0049]

[0050] Working process:

[0051] According to the driving function of the whole vehicle, this system mainly includes gear shifting, creeping, throttle torque control, energy recovery torque control, etc. According to the gear mode of the bridge, the vehicle driving process can be divided into starting mode, upshifting during driving, downshifting during driving, neutral gear, etc. Reversing is achieved by reversing the motor;

[0052] (1) The gear mode of the bridge changes as follows:

[0053] Starting mode: shift gears from neutral, axle mode 0-> axle mode 1, the drive system is in gear and can be driven.

[0054] The shifting sequence during driving is: axle mode 1 -> axle mode 2 -> axle mode 3 -> axle mode 4 -> axle mode 5 -> axle mode 6. According to the current output shaft speed and vehicle speed, as the vehicle speed increases, the axle mode will shift up in sequence according to the speed sequence set in the standard.

[0055] The downshifting sequence during driving is: bridge mode 6->bridge mode 5->bridge mode 4->bridge mode 3->bridge mode 2->bridge mode 1. According to the current output shaft speed and vehicle speed, the target mode of the bridge will be updated in real time, and a new mode will be found. When the accelerator is released and the brake is not pressed, the current mode will remain unchanged and the mode will not be lowered until the vehicle stops, and it will automatically return to the starting mode. In this process, if the accelerator is pressed again, the current vehicle speed and output shaft speed, the actual mode fed back by the TCU on the two bridges and the fault information of the two TCUs will be used to recalculate the mode and downshift. For example, in mode 6, if the accelerator is released for a while and then pressed again, the new mode may be mode 3, mode 4, or other modes. In the downshifting mode, the modes are not downshifted in sequence, so that the vehicle can be kept in the high mode for the longest time and the energy consumption of the vehicle can be reduced.

[0056] Neutral gear: In any mode, you can switch the current working mode to mode 0 by pressing the neutral gear handle.

[0057] (2) Creeping function of the bridge:

[0058] When starting from static and engaging the gear, without pressing the accelerator, the TCU in target mode will calibrate the creep-related parameter values ​​according to the specific working conditions, specific target creeping speed, etc., and send the virtual throttle value to the TCU on each bridge. The TCU on each bridge calculates the creep torque based on the received virtual throttle and enters the creeping of the whole vehicle.

[0059] (3) Throttle torque and energy recovery function of the bridge:

[0060] When you step on the accelerator to start the vehicle drive, the TCU on each bridge will independently receive the throttle and brake signals, and calculate the throttle torque and energy recovery torque respectively. By adjusting the torque-related parameter calibration of each TCU, it can be achieved that when the throttle and brake percentages are the same, the torque of the motor sent by each TCU controller is not much different, so that under the same working conditions, the torque and efficiency of each motor are consistent. This can make the motor torque and power work consistent and protect the life of the motor. In the process of dynamic driving and shifting of the whole vehicle, there will be no sudden change in torque, making the vehicle driving feel comfortable and smooth.

[0061] The above technical solutions are only preferred specific implementation methods of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be conceived by any technician familiar with the field within the technical scope disclosed by the present invention without creative work are all covered within the protection scope of the present invention.

Claims

1. A pure electric vehicle electric drive axle system, comprising a middle axle (1) and a rear axle (2), characterized in that: The middle bridge (1) adopts a non-power interruption structure of dual motors and dual gearboxes, and the rear bridge (2) adopts a structure of single motor and single gearbox.

2. The electric drive axle system of a pure electric vehicle as claimed in claim 1, characterized in that: A TCU controller is independently installed on the middle bridge (1) and the rear bridge (2), and the TCU controllers on the middle bridge (1) and the rear bridge (2) are respectively connected to the main TCU controller.

3. The electric drive axle system of a pure electric vehicle as claimed in claim 1, characterized in that: The dual gearbox is equipped with two independent output shaft speed sensors; the single gearbox is equipped with one output shaft speed sensor.

4. The electric drive axle system of a pure electric vehicle as claimed in claim 1, characterized in that: The double gearbox and the single gearbox both adopt two-speed gearboxes.

5. The electric drive axle system of a pure electric vehicle as claimed in claim 1, characterized in that: The dual motors and the single motor both use high-speed motors with a maximum speed of 12000 rpm.

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