A clutchless hybrid transmission assembly and gear shifting method

Abstract

This application relates to a clutchless hybrid power transmission assembly, including an engine, a first motor, a second motor, an input shaft, an intermediate shaft, a synchronizer, a differential assembly, a lift gear pair, a gear set, and a shift actuator. The output end of the engine is connected to the input shaft, and the output shaft of the first motor is connected to the input shaft via the lift gear pair. Two gear sets are provided, each including a corresponding driving gear and a driven gear. The driving gear is mounted on the input shaft, and the driven gear is mounted on the intermediate shaft. The synchronizer is located on the intermediate shaft between the two gear sets. No friction clutch or torque converter is used, and the synchronizer engages at extremely low speed differences, eliminating gear grinding and impact, resulting in a smooth and shock-free transmission.

Description

Technical Field

[0001] This application relates to the field of hybrid vehicle technology, specifically to a clutchless hybrid transmission assembly and gear shifting method. Background Technology

[0002] In the field of hybrid vehicles, the P13 configuration (where the P1 motor is connected to the engine crankshaft and the P3 motor is connected to the reduction gear or differential) is widely used due to its excellent fuel economy and power response characteristics. To further improve system efficiency, equipping this configuration with a two- or multi-speed transmission has become an important technological direction.

[0003] Currently, P13 hybrid transmissions equipped with multiple gears generally employ traditional friction clutches or hydraulic torque converters to achieve power coupling and decoupling between the engine and drive wheels, and to complete torque interruption control during gear shifts. However, the use of clutches brings many inherent drawbacks: on the one hand, clutches and their hydraulic or electronic actuation mechanisms significantly increase the number of system components, cost, weight, and axial dimensions; on the other hand, clutch control logic is complex, and shift quality is highly dependent on the calibration accuracy of parameters such as engagement pressure and slippage time; furthermore, friction plates inevitably wear over long-term use, leading to a decline in shift performance and affecting system reliability.

[0004] To overcome the above-mentioned defects, some existing technologies attempt to completely eliminate the clutch, but often have difficulties in terms of shift smoothness, especially during the shift process when the engine intervenes to drive, which is prone to large shocks or synchronization difficulties. Summary of the Invention

[0005] One of the objectives of this application is to provide a clutchless hybrid transmission assembly and gear shifting method to solve the problem of difficulty in shifting smoothness in the P13 hybrid transmission that completely eliminates the clutch.

[0006] To achieve the above objectives, in a first aspect, this application provides a clutchless hybrid power transmission assembly, including an engine, a first motor, a second motor, an input shaft, an intermediate shaft, a synchronizer, a differential assembly, a lift gear pair, a gear set, and a shift actuator. The output end of the engine is connected to the input shaft, and the output shaft of the first motor is connected to the input shaft through a speed-increasing gear pair. The gear set is provided in two sets. Each gear set includes a one-to-one corresponding driving gear and driven gear. The driving gear is mounted on the input shaft, and the driven gear is mounted on the intermediate shaft. The synchronizer is located on the intermediate shaft and between the two gear sets. The second motor is connected to the intermediate shaft via a reduction gear pair, and the differential assembly is connected to the intermediate shaft via a reduction gear set. The shifting actuator is used to drive the synchronizer to slide axially along the intermediate shaft, so that it engages or disengages with the gear ring of the driven gear in different gear positions.

[0007] Based on the above technical means, the second motor independently compensates for torque during gear shifting, ensuring continuous wheel driving force and avoiding the jerking sensation of traditional gear shifting, with no power interruption; the synchronizer engages at extremely low speed differences, eliminating gear grinding and impact, resulting in a smooth and shock-free experience; and no friction clutch or hydraulic torque converter is installed, thus directly avoiding the problems caused by clutches, such as increased number of parts, increased cost, increased axial size, complex control logic, and decreased reliability due to friction plate wear.

[0008] Furthermore, the speed-lifting gear pair includes a first speed-lifting gear and a second speed-lifting gear. The first speed-lifting gear is coaxially mounted on the input shaft, and the second speed-lifting gear is coaxially mounted on the output shaft of the first motor. The first speed-lifting gear and the second speed-lifting gear mesh with each other.

[0009] Based on the aforementioned technical means, the first motor, with the help of the wide speed range and high dynamic response provided by the speed-increasing gear pair, can quickly complete speed matching and achieve rapid and precise synchronization.

[0010] Furthermore, the two sets of gear sets are respectively a first gear set and a second gear set; the first gear set includes a first driving gear and a first driven gear, and the second gear set includes a second driving gear and a second driven gear; the first driving gear and the second driving gear are mounted on the input shaft, and the first driven gear and the second driven gear are mounted on the intermediate shaft, with the first driving gear and the first driven gear meshing with each other.

[0011] Based on the above technical means, the layout of the driving gear being fixedly connected to the input shaft and the driven gear being loosely fitted in the intermediate shaft, combined with the axial sliding of the synchronizer to select the gear, allows the synchronizer to engage only one of the driven gears during the gear shifting process, resulting in a compact structure and simple operation.

[0012] Furthermore, the reduction gear pair includes a first reduction gear and a second reduction gear. The first reduction gear is mounted on the output shaft of the second motor, and the second reduction gear is mounted on the intermediate shaft. The first reduction gear and the second reduction gear mesh with each other.

[0013] Based on the above technical means, speed reduction and torque increase between the second motor and the intermediate shaft were achieved.

[0014] Furthermore, the reduction gear set includes a main reduction drive gear and a main reduction driven gear. The main reduction drive gear is mounted on the intermediate shaft, and the main reduction driven gear is provided on the differential assembly. The main reduction drive gear and the main reduction driven gear mesh with each other.

[0015] Based on the above technical means, the power of the intermediate shaft is further reduced and increased in torque through the main reduction gear pair before being transmitted to the differential, which meets the actual needs of the wheels for low speed and high torque.

[0016] Furthermore, the differential assembly is provided with an output half-shaft, which is connected to the wheel.

[0017] Based on the aforementioned technical means, power is smoothly distributed to the left and right wheels through the differential, allowing the wheels to rotate at different speeds when turning.

[0018] Furthermore, the system includes a vehicle controller, wherein the first motor, the shift actuator, and the second motor are respectively signal-connected to the vehicle controller.

[0019] Based on the aforementioned technical means, the vehicle controller, as the central control unit, can collect driver needs and vehicle status in real time and coordinate the control of the first motor, the second motor, and the gear shifting actuator.

[0020] To achieve the above objectives, in a second aspect, this application also provides a method for shifting gears in a clutchless hybrid transmission assembly. The method is used to control the aforementioned clutchless hybrid transmission assembly to perform gear shifting, and includes the following steps: Step 1: In response to the gear shifting command, control the second motor to adjust its output torque to compensate for the wheel power loss during the gear shifting process; at the same time, control the first motor to apply a compensation torque in the opposite direction to the engine output torque so that the net load torque on the input shaft is reduced to zero. Step 2: After the net load torque returns to zero, control the shift actuator to drive the synchronizer to disengage from the driven gear corresponding to the current gear, so that the synchronizer is in neutral position; Step 3: Control the first motor to adjust its speed, increase or decrease the speed of the input shaft from the first synchronous speed corresponding to the current gear to the second synchronous speed corresponding to the target gear, and control the shifting actuator to drive the synchronizer to engage with the driven gear corresponding to the target gear; Step 4: Control the first motor to gradually reduce the compensation torque until it reaches zero, and control the engine to restore the required output torque; at the same time, control the second motor to gradually restore its output torque to the target drive torque.

[0021] Based on the aforementioned technical means, the second motor adjusts its output torque to precisely compensate for the driving force or braking force lost due to the unloading of the engine and the first motor, so that the total torque of the wheels remains continuous throughout the shifting process, completely eliminating the feeling of power interruption in traditional shifting; the first motor is used to quickly increase or decrease the input shaft speed from the current gear synchronization value to the target gear synchronization value, overcoming the difficulty of synchronization in existing clutchless solutions; the synchronizer engages with the driven gear of the target gear at extremely low speed differences, and the synchronizer locking ring requires almost no friction, avoiding gear grinding and shifting impact, resulting in a smooth and shock-free shift.

[0022] Furthermore, in the third step, when the first motor adjusts its speed, the engine is controlled to cut off fuel or output low torque to reduce the resistance from the engine when the first motor adjusts its speed.

[0023] Based on the above technical means, the engine basically no longer outputs positive or negative torque, but only acts as a load with rotational inertia. The first motor only needs to overcome the frictional torque of the engine and the inertia of its own rotor to complete the speed regulation, and the speed regulation power and speed regulation time are greatly reduced.

[0024] Furthermore, in the third step, when the difference between the actual rotational speed of the input shaft and the second synchronous rotational speed is within the preset threshold and remains stable for a preset time, the shifting actuator is controlled to drive the synchronizer to engage with the driven gear corresponding to the target gear.

[0025] Based on the above technical means, there is no speed difference between the synchronizer's engagement sleeve and the engagement gear ring of the driven gear corresponding to the target gear position. The engagement process is very smooth. The locking ring inside the synchronizer hardly needs to perform friction synchronization. The engagement sleeve can be directly pushed into place without producing tooth knocking or obvious resistance.

[0026] Furthermore, in the fourth step, the compensation torque of the first motor is reduced in a linear or gradual manner.

[0027] The above-mentioned technical means can avoid sudden torque changes in the first motor.

[0028] Furthermore, in the third step, when the difference between the actual rotational speed of the input shaft and the second synchronous rotational speed is less than a preset threshold, the shifting actuator is controlled to drive the synchronizer to engage with the driven gear corresponding to the target gear.

[0029] Based on the above technical means, there is no speed difference between the engagement sleeve of the synchronizer and the engagement ring of the driven gear corresponding to the target gear, and the engagement process is very smooth.

[0030] The beneficial effects of this application are: In this application, when upshifting using the clutchless hybrid transmission assembly, firstly, in response to the upshift command, the second motor increases its output torque to compensate for the wheel power loss during the shift process, while the first motor applies a compensation torque in the opposite direction to the engine's output torque, causing the net load torque on the input shaft to return to zero. Secondly, the shift actuator drives the synchronizer to disengage from the first gear driven gear, placing the synchronizer in neutral. Then, the first motor actively adjusts its speed, reducing the input shaft speed from the speed corresponding to the first gear to the speed corresponding to the second gear. When the difference between the actual speed and the target speed is less than a preset threshold, the shift actuator drives the synchronizer to engage with the second gear driven gear. Finally, the first motor gradually reduces the compensation torque to zero, the engine resumes outputting the required torque, and the second motor gradually restores its output torque to the target drive torque, completing the upshift.

[0031] It is evident that using a clutchless hybrid transmission assembly for gear shifting offers the following advantages: First, the second motor independently compensates for torque during gear shifts, ensuring continuous wheel drive and avoiding the jerking sensation of traditional gear shifts, with no power interruption. Second, the first motor, leveraging the wide speed range and high dynamic response provided by the lift gear pair, quickly completes speed matching and achieves rapid and precise synchronization. Third, the synchronizer engages at extremely low speed differences, eliminating gear grinding and impact, resulting in a smooth and shock-free experience. Fourth, the absence of any friction clutch or torque converter directly avoids the problems associated with clutches, such as increased component quantity, higher costs, larger axial dimensions, more complex control logic, and decreased reliability due to friction plate wear. Attached Figure Description

[0032] Figure 1 This illustration shows a schematic diagram of the structure of a clutchless hybrid power transmission assembly provided in an embodiment of this application; Figure 2 This diagram illustrates a method for shifting gears in a clutchless hybrid transmission assembly according to another embodiment of this application.

[0033] In the diagram: 1. Engine; 2. First motor; 3. Input shaft; 4. First gear drive gear; 5. Second gear drive gear; 6. First gear driven gear; 7. Second gear driven gear; 8. Synchronizer; 9. Intermediate shaft; 10. Main reduction drive gear; 11. Differential assembly; 12. Main reduction driven gear; 13. Output half shaft; 14. Second motor; 15. Reduction gear pair; 16. First output shaft; 17. Speed-up gear pair; 18. Second output shaft. Detailed Implementation

[0034] The embodiments of this application will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be understood that the preferred embodiments are only for illustrating this application and are not intended to limit the scope of protection of this application.

[0035] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. Therefore, the drawings only show the components related to this application and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0036] The embodiments of this application will be described below with reference to the accompanying drawings and preferred embodiments. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. This application can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be understood that the preferred embodiments are only for illustrating this application and are not intended to limit the scope of protection of this application.

[0037] To facilitate understanding of the embodiments of this application, the following will provide further explanation and description with reference to the accompanying drawings and specific embodiments. These embodiments do not constitute a limitation on the embodiments of this application.

[0038] The first aspect of this application provides a clutchless hybrid transmission assembly suitable for hybrid vehicles, particularly for hybrid systems employing a P13 configuration and having two forward gears.

[0039] The clutchless hybrid transmission assembly includes an engine 1, a first motor 2, a second motor 14, an input shaft 3, an intermediate shaft 9, a synchronizer 8, a differential assembly 11, a lift gear pair 17, a gear set, and a shift actuator; the output end of the engine 1 is connected to the input shaft 3, and the output shaft of the first motor 2 is connected to the input shaft 3 via the lift gear pair 17. The gear set has two sets, each set including a corresponding driving gear and driven gear. The driving gear is mounted on the input shaft 3, and the driven gear is mounted on the intermediate shaft 9. The synchronizer 8 is located on the intermediate shaft 9 and between the two gear sets. The second motor 14 is connected to the intermediate shaft 9 through a reduction gear pair 15, and the differential assembly 11 is connected to the intermediate shaft 9 through a reduction gear set. The shifting actuator is used to drive the synchronizer 8 to slide axially along the intermediate shaft 9, so that it engages or disengages with the engagement gear ring of the driven gear of different gears.

[0040] When shifting gears using a hybrid transmission assembly without a clutch, taking upshifting as an example, firstly, in response to the upshift command, the second motor 14 increases its output torque to compensate for the loss of wheel power during the shift process. At the same time, the first motor 2 applies a compensation torque in the opposite direction to the output torque of the engine 1, so that the net load torque on the input shaft 3 is reduced to zero. Secondly, the shift actuator drives the synchronizer 8 to disengage from the first gear driven gear 6, so that the synchronizer 8 is in neutral. Then, the first motor 2 actively adjusts its speed, reducing the speed of the input shaft 3 from the speed corresponding to the first gear to the speed corresponding to the second gear. When the difference between the actual speed and the target speed is less than a preset threshold, the shift actuator drives the synchronizer 8 to engage with the second gear driven gear 7. Finally, the first motor 2 gradually reduces the compensation torque to zero, the engine 1 resumes outputting the required torque, and the second motor 14 gradually restores its output torque to the target drive torque, completing the upshift.

[0041] It is evident that using a clutchless hybrid transmission assembly for gear shifting offers the following advantages: First, the second motor 14 independently compensates for torque during gear shifts, ensuring continuous wheel drive and avoiding the jerking sensation of traditional gear shifts, with no power interruption. Second, the first motor 2, leveraging the wide speed range and high dynamic response provided by the lift gear pair 17, quickly completes speed matching and achieves rapid and precise synchronization. Third, the synchronizer 8 engages at extremely low speed differences, eliminating gear grinding and impact, resulting in a smooth and shock-free experience. Fourth, the absence of any friction clutch or torque converter directly avoids the problems associated with clutches, such as increased component quantity, higher costs, larger axial dimensions, more complex control logic, and decreased reliability due to friction plate wear.

[0042] In this embodiment, the crankshaft of engine 1 is rigidly connected to the input shaft 3, and no friction clutch or torque converter is provided between them. That is to say, once engine 1 is running, input shaft 3 will rotate at the same speed as the crankshaft of engine 1.

[0043] In this embodiment, the output shaft of the first motor 2 is named the first output shaft 16, and the output shaft of the second motor 14 is named the second output shaft 18.

[0044] In this embodiment, the speed-increasing gear pair 17 includes a first speed-increasing gear and a second speed-increasing gear. The first speed-increasing gear is coaxially mounted on the input shaft 3 and rotates together with the input shaft 3. The second speed-increasing gear is coaxially mounted on the output shaft of the first motor 2 and rotates together with the rotor of the first motor 2. The first speed-increasing gear and the second speed-increasing gear mesh with each other.

[0045] It's important to understand that by appropriately selecting the gear ratio of the speed-lift gear pair 17, the rated operating speed of the first motor 2 can be higher than the commonly used speed range of the engine 1. For example, the maximum speed of the engine 1 is 6000 rpm, while the maximum speed of the first motor 2 can be designed to be 12000 rpm or even higher. This allows the first motor 2 to operate efficiently over a wider speed range, providing the necessary speed regulation capability for subsequent active synchronous speed control. Simultaneously, since the first motor 2 and the input shaft 3 are rigidly connected via the speed-lift gear pair 17, and there is no clutch between them, the rotors of the engine 1 and the first motor 2 always rotate synchronously at a fixed speed ratio; that is, the speed of the input shaft 3 is always equal to the speed of the first motor 2 divided by the transmission ratio of the speed-lift gear pair 17.

[0046] In this embodiment, the first motor 2 is an integrated generator and starter, which has the functions of starting the engine, generating electricity, actively regulating speed and assisting drive.

[0047] In this embodiment, the intermediate shaft 9 is arranged parallel to the input shaft 3, and the center distance between them is determined according to the module and number of teeth of the gears in the gear set. The two gear sets are the first gear set and the second gear set, respectively. The first gear set includes a first gear driving gear 4 and a first gear driven gear 6, and the second gear set includes a second gear driving gear 5 and a second gear driven gear 7. The driving gear of the gear set is mounted on the input shaft 3, and the driven gear of the gear set and the synchronizer 8 are mounted on the intermediate shaft 9.

[0048] Specifically, the first gear drive gear 4 and the second gear drive gear 5 are mounted on the input shaft 3. These two drive gears do not rotate relative to the input shaft 3; they rotate together with the input shaft 3. The first gear drive gear 4 is used to transmit power in the first gear, and the second gear drive gear 5 is used to transmit power in the second gear. It should be noted that the axial positions of the two drive gears on the input shaft 3 can be rationally arranged according to the internal space of the transmission. Typically, the first gear drive gear 4 is closer to the engine 1 side, and the second gear drive gear 5 is further away from the engine 1 side, or vice versa.

[0049] Furthermore, a first-gear driven gear 6 and a second-gear driven gear 7 are loosely mounted on the intermediate shaft 9. "Loosely mounted" means that the first-gear driven gear 6 and the second-gear driven gear 7 are mounted on the intermediate shaft 9 via needle roller bearings or other rolling bearings. The first-gear driven gear 6 and the second-gear driven gear 7 can rotate freely relative to the intermediate shaft 9 without causing the intermediate shaft 9 to rotate. This design ensures that when the synchronizer 8 is in neutral, even if the input shaft 3 rotates, causing the first-gear driven gear 6 or the second-gear driven gear 7 to idle, power will not be transmitted to the intermediate shaft 9, thus achieving mechanical decoupling between the engine 1 and the wheels.

[0050] Furthermore, the first gear drive gear 4 and the first gear driven gear 6 are constantly meshed, and the second gear drive gear 5 and the second gear driven gear 7 are constantly meshed. Constant meshing means that regardless of the position of the synchronizer 8, the drive gear and the driven gear are always meshed and will not disengage. The constant meshing design can reduce the impact during gear shifting because the gear teeth of the drive gear and the driven gear always remain in contact. There is no need to engage the gears during gear shifting; it is only necessary to select which driven gear to lock with the intermediate shaft 9 through the synchronizer 8.

[0051] Furthermore, the synchronizer 8 is fixedly connected to the intermediate shaft 9 via an internal spline, and both rotate at the same speed, located between the first driven gear 6 and the second driven gear 7. The engaging sleeve (external gear ring) of the synchronizer 8 slides axially along the intermediate shaft 9 under the drive of the shifting actuator. When the engaging sleeve slides to one side, it first pushes the locking ring of the synchronizer 8 to press against the conical surface of the target driven gear, using friction to make the speeds of the intermediate shaft 9 and the target driven gear tend to be the same; when the speed difference decreases to a certain extent, the locking ring releases, and the engaging sleeve continues to slide and meshes with the engaging gear ring of the target driven gear, thus achieving a rigid connection. In this embodiment, since the active speed regulation of the first motor 2 can reduce the speed difference between the input shaft 3 and the intermediate shaft 9 to a very small range (e.g., within ±30 rpm), the locking ring of the synchronizer 8 hardly needs to bear the main synchronization work, thus significantly reducing the wear of the synchronizer 8 and significantly improving shifting smoothness.

[0052] In this embodiment, the shifting actuator is used to drive the synchronizer 8 to slide axially along the intermediate shaft 9. The shifting actuator can typically take various forms; a preferred method is a motor-driven worm gear mechanism. This mechanism includes a shifting motor, a worm, a worm wheel, and a shift fork. The output shaft of the shifting motor drives the worm to rotate, which in turn drives the worm wheel to rotate. The worm wheel converts the rotational motion into linear motion of the shift fork via the shift fork shaft, and the shift fork then pushes the engaging sleeve of the synchronizer 8 to move. The advantages of this mechanism are good self-locking (worm gears have self-locking characteristics), strong position holding capability, and simple motor control.

[0053] Another preferred approach is an electro-hydraulic servo mechanism, which includes a solenoid valve, a hydraulic cylinder, and a shift fork. The movement of the shift fork is achieved by controlling the pressure and flow direction of the hydraulic oil. The advantages of an electro-hydraulic servo mechanism are fast response and high thrust, but it requires an additional hydraulic power source and oil circuit.

[0054] This embodiment does not limit the specific type of shifting actuator, as long as it can achieve precise axial position control and has position feedback.

[0055] In this embodiment, the second motor 14 is an independent drive motor, mainly used for pure electric drive, energy recovery, and auxiliary drive in parallel mode. The second motor 14 is connected to the intermediate shaft 9 via a reduction gear pair 15. The reduction gear pair 15 includes a first reduction gear and a second reduction gear. Specifically, the first reduction gear is mounted on the output shaft of the second motor 14 and rotates with the rotor of the second motor 14, while the second reduction gear is mounted on the intermediate shaft 9 and rotates with the intermediate shaft 9. The first reduction gear and the second reduction gear mesh with each other.

[0056] By selecting the gear ratio of the reduction gear pair 15, the output torque of the second motor 14 can be reduced and increased to meet the torque requirements of the wheels. Typically, the maximum speed of the second motor 14 is relatively high (e.g., above 12,000 rpm). After reduction, the speed of the intermediate shaft 9 is reduced to a range that matches the vehicle speed. The transmission ratio of the reduction gear pair 15 can be calibrated according to the vehicle parameters.

[0057] In this embodiment, the differential assembly 11 and the intermediate shaft 9 are connected by a reduction gear set. The reduction gear set includes a main reduction drive gear 10 and a main reduction driven gear 12. The main reduction drive gear 10 is fixedly mounted on the intermediate shaft 9 and rotates with the intermediate shaft 9. The main reduction driven gear 12 is fixedly mounted on the housing of the differential assembly 11 and rotates with the differential assembly 11. The main reduction drive gear 10 and the main reduction driven gear 12 mesh with each other.

[0058] It should be noted that the transmission ratio of the main reduction gear set is usually relatively large (e.g., between 3 and 5), used to convert the high speed and low torque of the intermediate shaft 9 into low speed and high torque to meet the driving force requirements of the wheels. The function of the differential assembly 11 is to allow the left and right wheels to rotate at different speeds when the vehicle is turning, while distributing power evenly to the two output half shafts 13. The output half shafts 13 connect the differential assembly 11 to the left and right wheels, transmitting power to the wheels.

[0059] This transmission assembly never incorporates any form of friction clutch or torque converter throughout the entire power transmission path. Specifically, there is no clutch between engine 1 and input shaft 3, and the first motor 2 is rigidly connected to input shaft 3 via a lifting gear pair 17, also without a clutch. Although synchronizer 8 has engagement and disengagement functions, it is a mechanical shifting element, not a friction clutch. Its function is to lock or unlock the driven gear to intermediate shaft 9, not to control the on / off state of power from engine 1. Therefore, the on / off state of power between engine 1 and drive wheels, as well as the shifting of gears, is entirely achieved through the combined torque and speed control of the first motor 2 and the second motor 14, combined with the operation of synchronizer 8. This design completely eliminates the problems of cost, weight, wear, and control complexity associated with traditional clutches.

[0060] This transmission assembly can operate in multiple modes, including pure electric drive mode, series range extender mode, engine direct drive mode, parallel drive mode, and energy recovery mode. The power transmission path and the status of each component are described below for each mode.

[0061] First pure electric drive mode: The pure electric drive mode is suitable for low-speed start-up, low-speed urban cruising, low-load driving, and when the battery has sufficient charge. In this mode, engine 1 remains off and stationary to save fuel, and the first motor 2 also remains stationary. Synchronizer 8 is placed in neutral, i.e., not engaged with any driven gear. This is to prevent engine 1 and the first motor 2 from being dragged by the wheels, thereby avoiding unnecessary mechanical drag losses and back electromotive force losses. The second motor 14, as the sole drive source, outputs positive torque (drive torque). Power is transmitted from the rotor of the second motor 14 to the output shaft of the second motor 14, and then to the first reduction gear fixed on the output shaft of the second motor 14. Since the first reduction gear meshes with the second reduction gear, the power is transmitted to the intermediate shaft 9. The main reduction drive gear 10 is fixedly installed on the intermediate shaft 9. The power continues to be transmitted to the main reduction driven gear 12 meshing with the main reduction drive gear 10, which in turn drives the housing of the differential assembly 11 to rotate. The differential assembly 11 distributes power to the left and right output half shafts 13, ultimately driving the wheels to rotate. Throughout the process, since the synchronizer 8 is in neutral, the input shaft 3 and the connected engine 1 and first motor 2 do not participate in power transmission, so the system efficiency is high.

[0062] Second, the series range extender mode: The series range extender mode is suitable for situations where the battery charge is low and the vehicle is cruising at low to medium speeds. In this mode, the mechanical power output from the crankshaft of the engine 1 is transmitted to the first motor 2 through the speed-up gear pair 17. The first motor 2 acts as a generator, applying negative torque to convert mechanical energy into electrical energy. This electrical energy is supplied to the second motor 14 via an inverter or the power battery bus. The second motor 14 acts as a drive motor, outputting positive torque. Its output shaft transmits power to the intermediate shaft 9 through the reduction gear pair 15. The main reduction drive gear 10 fixed on the intermediate shaft 9 drives the meshing main reduction driven gear 12 to rotate. The main reduction driven gear 12 is fixed to the housing of the differential assembly 11, thereby driving the differential housing and the internal planetary gear mechanism to rotate. Finally, the power is distributed to the wheels through the left and right output half shafts 13. During this process, the synchronizer 8 is in neutral, ensuring that there is no mechanical connection between the engine 1 and the first motor 2 and the wheels, achieving complete decoupling of engine speed and vehicle speed. In other words, all the mechanical power output by the engine 1 is converted into electrical power by the first motor 2 and is not directly transmitted to the wheels. The speed and torque of the second motor 14 can be independently adjusted according to the vehicle speed and driver's needs, and the driving experience is similar to that of a pure electric vehicle.

[0063] Third, Engine 1 Direct Drive Mode: Engine 1 direct drive mode is suitable for medium-to-high-speed cruising when Engine 1 is operating in its most efficient range. In this mode, the battery charge can be at a medium or high level, but to fully utilize the high efficiency of Engine 1, direct drive of the vehicle by Engine 1 is prioritized to reduce energy conversion losses. In this mode, synchronizer 8 engages first or second gear (the specific gear is selected based on vehicle speed), establishing a direct mechanical connection path from Engine 1 to the wheels. Specifically, the power output from engine 1 is first transmitted to input shaft 3 via speed-up gear pair 17. At this time, first motor 2 can be in idle, power-assisted, or generator mode depending on the strategy, but without affecting the main path. Input shaft 3 drives the first gear drive gear 4 or second gear drive gear 5 fixedly mounted on it to rotate. This drive gear maintains constant mesh with the corresponding first gear driven gear 6 or second gear driven gear 7 loosely fitted on intermediate shaft 9. Power is transmitted to intermediate shaft 9 via synchronizer 8 engaged in the corresponding gear. The main reduction drive gear 10 fixedly mounted on intermediate shaft 9 rotates accordingly, driving the main reduction driven gear 12 meshing with it to rotate. Since the main reduction driven gear 12 is fixed to the housing of differential assembly 11, the rotation of the housing distributes power to the output half shafts 13 on the left and right sides through the internal planetary gear mechanism, ultimately driving the wheels. During this process, second motor 14 does not output drive torque (it can be in standby or low-power generator mode), and the vehicle is directly driven by engine 1 through the mechanical path.

[0064] It should be noted that in this mode, the first motor 2 can be in several states: First motor 2 can act as an assist motor, outputting positive torque to drive the engine 1 together. This can supplement the torque of the engine 1 when it is insufficient, or adjust the operating point of the engine 1 to a more efficient range. Second, the first motor 2 can act as a generator, outputting a small negative torque to charge the vehicle. In this case, part of the power of the engine 1 is used to drive the vehicle, and the other part of the power is converted into electrical energy and stored in the battery through the first motor 2. Third, the first motor 2 can idle, with zero output torque, and only rotate with the input shaft 3.

[0065] Fourth, parallel drive mode: Parallel drive mode is suitable for scenarios requiring high power output, such as rapid acceleration, high-speed overtaking, and high-load hill climbing. In this mode, power is transmitted to the wheels simultaneously along two paths. The first path is a mechanical direct drive path. Specifically, the power output from engine 1 is transmitted to input shaft 3 via speed-up gear pair 17. Input shaft 3 drives the fixed drive gear (first gear drive gear 4 or second gear drive gear 5) to rotate. This drive gear is constantly meshed with the corresponding driven gear (first gear driven gear 6 or second gear driven gear 7) loosely fitted on intermediate shaft 9. Power is transmitted to intermediate shaft 9 through synchronizer 8, which is engaged with the corresponding gear.

[0066] The second path is the electric drive path. Specifically, the second motor 14 outputs positive torque, and its output shaft transmits power directly to the intermediate shaft 9 through the reduction gear pair 15.

[0067] The power from these two paths converges on the intermediate shaft 9, jointly driving the main reduction drive gear 10 fixed on the intermediate shaft 9 to rotate. The main reduction drive gear 10 drives the meshing main reduction driven gear 12 to rotate. The main reduction driven gear 12 is fixed to the housing of the differential assembly 11. The rotation of the housing distributes power to the output half-shafts 13 on the left and right sides through the internal planetary gear mechanism, ultimately driving the wheels. This achieves the superimposed torque output of the engine 1 and the second motor 14, meeting the high power requirements. It should be noted that since the differential assembly 11 is a confluence element, the two power paths are coupled within it and jointly drive the wheels. The parallel drive mode can output a torque far exceeding the maximum torque of a single power source, meeting the high power requirements of the vehicle.

[0068] Fifth, Energy Recovery Mode: Energy recovery mode is suitable for vehicle coasting or braking. In this mode, the inertial kinetic energy of the wheels is first transmitted to the differential assembly 11 through the output half-shaft 13, driving the differential housing and the main reduction driven gear 12 fixed thereon to rotate. The main reduction driven gear 12 transmits power to the main reduction drive gear 10 meshing with it, which in turn drives the intermediate shaft 9 to rotate. The intermediate shaft 9 transmits power to the output shaft of the second motor 14 through the reduction gear pair 15, driving the second motor 14 to rotate as a generator, converting mechanical energy into electrical energy and recharging it back to the power battery. During this process, the synchronizer 8 is in neutral, ensuring that there is no mechanical connection between the engine 1, the first motor 2, and the intermediate shaft 9, avoiding kinetic energy loss due to dragging by the engine 1, thereby achieving high-efficiency braking energy recovery.

[0069] It is evident that the clutchless hybrid transmission assembly has the following significant advantages over existing technologies: First, by completely eliminating the traditional friction clutch and its hydraulic or electronic actuation mechanism, the number of internal parts of the transmission is greatly reduced, the axial dimension is shortened, and the weight is reduced, thereby reducing manufacturing costs and improving the compactness of the overall vehicle layout.

[0070] Secondly, by actively applying a compensating torque opposite to that of the engine 1 during gear shifting, the net load on the input shaft 3 is reduced to zero, allowing the synchronizer 8 to easily downshift with almost no load. At the same time, the first motor 2 utilizes its wide speed range and fast response capability to actively and precisely synchronize the speed of the input shaft 3 to the speed required for the target gear, enabling the synchronizer 8 to engage with extremely low speed difference, avoiding the shock and gear grinding of traditional gear shifting. Meanwhile, the second motor 14 independently adjusts its output torque during gear shifting to compensate for the driving force lost due to the unloading of the engine 1 in real time, ensuring that the total driving torque at the wheels is continuous and uninterrupted. In this way, smooth gear shifting and no power interruption are achieved, achieving a smoothness quality that surpasses traditional clutch gear shifting.

[0071] Third, the active speed regulation of the first motor 2 significantly reduces the synchronous load of the synchronizer 8, thereby significantly reducing the wear of the synchronizer 8 and improving the reliability and durability of the entire transmission system.

[0072] Fourth, when switching between various working modes such as pure electric, series, parallel, and direct drive, the active speed regulation of the first motor 2 and the torque compensation of the second motor 14 can ensure a smooth and reliable switching process, avoiding the impact or failure caused by changes in clutch control parameters in traditional solutions.

[0073] As a preferred embodiment, the first motor 2 is a permanent magnet synchronous motor because it has high efficiency, high power density, and fast dynamic response characteristics, making it very suitable for active speed regulation and torque compensation. Of course, an induction motor is also feasible, but its control complexity and efficiency are slightly inferior.

[0074] The second aspect of this application provides a method for shifting gears in a clutchless hybrid transmission assembly, which is used to control the aforementioned clutchless hybrid transmission assembly to perform gear shifting.

[0075] This method is executed by the Vehicle Control Unit (VCU), which is connected to the Electronic Control Unit (ECU) of engine 1, the controller of the first motor 2, the controller of the second motor 14, and the driver signals of the shift actuator. The VCU can collect driver operation signals (such as accelerator pedal opening, brake pedal opening, and gear selection) and vehicle status signals (such as vehicle speed, battery SOC, motor speeds, engine 1 speed, and input shaft 3 speed) in real time, and execute the shift operation according to the preset control strategy.

[0076] Since gear shifting includes upshifting and downshifting, it is necessary to describe the upshifting and downshifting processes separately.

[0077] The following describes in detail the steps of shifting gears, taking the vehicle in parallel drive mode or engine direct drive mode as an example, from first gear (low gear) to second gear (high gear).

[0078] Step 1: When the VCU determines that it is necessary to switch from the current gear (e.g., first gear) to the target gear (e.g., second gear) based on the current vehicle speed, the driver's required torque (i.e., accelerator pedal opening) and the principle of optimal system efficiency, the VCU issues a gear switching command.

[0079] Upon receiving the gear shift command, the VCU first controls the first motor 2 to apply a compensating torque opposite to the output torque of the engine 1, so that the net load torque on the input shaft 3 is reduced to zero, thereby facilitating the synchronizer 8 to disengage from the current gear. At the same time, by controlling the second motor 14 to increase its output torque, it compensates for the driving force that will be lost during the gear shift, so as to avoid a significant power interruption at the wheels.

[0080] It needs to be explained that, under typical conditions where the vehicle is accelerating (i.e., the driver has pressed the accelerator pedal) and needs to shift up, engine 1 and the first motor 2 (possibly with power assist) are outputting positive torque to the wheels through the current gear (first gear). If the current gear is disengaged directly, this positive torque will suddenly disappear, causing a sharp drop in wheel drive force and producing a noticeable jerk. Therefore, the VCU instructs the second motor 14 to add an additional torque ΔTp to the original drive torque. The magnitude of this additional torque is calibrated based on the total torque output by engine 1 and first motor 2, typically 100% to 110% of the target compensation amount. That is, the second motor 14 needs to output additional positive torque to compensate for the torque of engine 1 and first motor 2 that is about to disengage. The VCU detects the total drive torque at the current wheels through sensors and then instructs the second motor 14 to increase its output torque ΔTp, so that the sum of the increased output torque of the second motor 14 and the current output torque of engine 1 can reach the torque required by the driver.

[0081] Furthermore, the purpose of the VCU controlling the first motor 2 to apply a compensating torque opposite to the output torque of the engine 1, so as to bring the net load torque on the input shaft 3 to zero, is as follows: Under the current operating conditions, the engine 1 outputs a positive torque T (e.g., 100 Nm), and the first gear drive gear 4 on the input shaft 3 meshes with the first gear driven gear 6, transmitting the torque to the intermediate shaft 9 through the synchronizer 8. Without compensation, the gear pair on the input shaft 3 would bear a large load, resulting in a large positive pressure between the engaging sleeve of the synchronizer 8 and the engaging gear ring of the first gear driven gear 6. Forcibly disengaging would cause wear and impact. Therefore, the VCU instructs the first motor 2 to output a compensating torque T1 opposite to the torque direction of the engine 1. Since the engine 1 outputs a positive torque, the first motor 2 needs to output a negative torque. The magnitude of the compensating torque should make T + T1 ≈ 0 (considering the friction loss and inertia of the gear pair, T1 is usually taken as -(0.95 to 1.05) × T). For example, if the engine 1 outputs 100 Nm, the first motor 2 can output a compensating torque of -95 Nm to -105 Nm. In this way, on the input shaft 3, the torque of engine 1 and the compensating torque of the first motor 2 cancel each other out, and the net torque is close to zero. At this time, the meshing force between the first gear drive gear 4 and the first gear driven gear 6 is greatly reduced, and the normal pressure between the synchronizer 8 engagement sleeve and the engagement gear ring is also close to zero, which facilitates the disengagement of the synchronizer 8 engagement sleeve from the first gear driven gear 6. This is equivalent to the action of pressing the clutch pedal in traditional clutch shifting, but this solution relies entirely on motor torque control to achieve this, without the need for a mechanical clutch.

[0082] Step 2: After confirming that the net load torque on the input shaft 3 has returned to zero, the VCU sends a command to the shift actuator to drive the synchronizer 8 to slide axially along the intermediate shaft 9, separating it from the engagement gear ring of the driven gear corresponding to the current gear (i.e., the first gear driven gear 6). Since the load on the input shaft 3 has been unloaded in the first step, there is almost no positive pressure between the engagement sleeve of the synchronizer 8 and the engagement gear ring of the first gear driven gear 6. Therefore, the separation process is very smooth with minimal resistance. The shift actuator only needs to overcome the sliding friction inside the synchronizer 8 (such as the friction between the shift fork and the engagement sleeve) to complete the downshift action.

[0083] In this embodiment, the VCU can directly measure whether the net load torque of the input shaft 3 is close to zero using a torque sensor mounted on the input shaft 3.

[0084] In this embodiment, the VCU monitors the position of the synchronizer 8 in real time using a position sensor (e.g., a Hall sensor or potentiometer mounted on the shift fork or synchronizer 8 engagement sleeve). When the position sensor indicates that the synchronizer 8 has returned to the neutral position (i.e., neither engaged with the first gear driven gear 6 nor the second gear driven gear 7), the VCU confirms that the downshifting step is complete. If jamming occurs during downshifting or the position sensor feedback is abnormal, the VCU will perform fault handling, such as attempting to downshift again or reporting a fault code.

[0085] Step 3: After downshifting, the VCU controls the first motor 2 to adjust its speed, reducing the speed of the input shaft 3 from the first synchronous speed V3 corresponding to the first gear to the second synchronous speed V2 corresponding to the second gear. When the difference between the actual speed V3 of the input shaft 3 and the second synchronous speed V2 is less than a preset threshold, the VCU controls the shifting actuator to drive the synchronizer 8 to engage with the driven gear corresponding to the target gear.

[0086] In this embodiment, the VCU controls the first motor 2 to adjust its speed, reducing the speed of the input shaft 3 from the first synchronous speed V3 corresponding to the first gear to the second synchronous speed V2 corresponding to the second gear. The specific process is as follows: Based on the vehicle speed Vs measured by the current vehicle speed sensor, combined with the speed ratio of the differential assembly 11, the speed ratio of the final drive, and the wheel radius, the VCU can calculate the current actual speed V1 of the intermediate shaft 9. Then, based on the speed ratio i of the second gear (i.e., the gear ratio between the second gear drive gear 5 and the second gear driven gear 7), the VCU calculates the target synchronous speed V2 (second synchronous speed) that the input shaft 3 needs to achieve. The calculation formula is: V2 = V1 × i. Simultaneously, the VCU measures the current actual speed V3 (first synchronous speed) of the input shaft 3 through the speed sensor.

[0087] After that, the VCU sends a speed control command to the controller of the first motor 2. After the first motor 2 enters the speed control mode, according to the difference between the current speed V3 and the target speed V2, it outputs a negative torque. This negative torque acts on the input shaft 3 through the speed increasing gear pair 17, causing the actual speed V3 of the input shaft 3 to start to rapidly decrease.

[0088] It should be noted that during the upshift process, since the gear ratio of the second gear is smaller than that of the first gear, V2 < V3. That is to say, the input shaft 3 needs to reduce its speed, and the opposite is true during the downshift process, where the speed needs to be increased.

[0089] In this embodiment, in order to reduce the resistance from the engine 1 when the first motor 2 adjusts its speed, the VCU simultaneously sends a command to the electronic control unit ECU of the engine 1 to control the engine 1 to be in a fuel cut-off or extremely low torque output state. Specifically, the ECU stops supplying fuel to the fuel injectors of the engine 1 (fuel cut-off), or closes the throttle valve to the minimum position, causing the engine 1 to only output an extremely low torque (e.g., below 5 Nm, only for maintaining its own operation). At this time, the engine 1 basically no longer outputs positive or negative torque and only acts as a load with a moment of inertia. The first motor 2 only needs to overcome the friction torque of the engine 1 and the inertia of its own rotor to complete the speed adjustment, and both the speed adjustment power and the speed adjustment time are significantly reduced.

[0090] When the difference between the actual speed V3 of the input shaft 3 and the second synchronous speed V2 is less than the preset threshold, the specific process of controlling the shift actuator to drive the synchronizer 8 to engage with the driven gear corresponding to the target gear is as follows: The VCU continuously monitors the actual speed V3 of the input shaft 3 and compares it with the target synchronous speed V2. When the absolute value of the difference between the two is less than the preset threshold, the VCU determines that the speeds are basically synchronized. After synchronization is completed, the VCU commands the shift actuator to drive the synchronizer 8 to slide axially so that it meshes with the engaging gear ring of the driven gear corresponding to the target gear (i.e., the second gear driven gear 7). Optionally, the preset threshold can be set to ±30 rpm, but it can be calibrated according to the performance of the synchronizer 8 and the requirements for shift quality (e.g., ±20 rpm or ±50 rpm).

[0091] To ensure stability, the VCU can also add a condition: After the difference is within the threshold and remains stable for a preset time (e.g., 20 milliseconds), it is determined that synchronization is completed. This can avoid misjudgment due to instantaneous jitter of the speed.

[0092] It should be noted that when the speed of the input shaft 3 is adjusted to V2, the speed of the second driven gear 7 is equal to the speed of the intermediate shaft 9. At this time, there is no speed difference between the engagement sleeve of the synchronizer 8 and the engagement gear ring of the second driven gear 7, and the engagement process is very smooth. The locking ring inside the synchronizer 8 hardly needs to perform friction synchronization, and the engagement sleeve can be directly pushed into place without producing tooth knocking or obvious resistance.

[0093] Step 4: After synchronizer 8 is engaged in the target gear, the torque output of engine 1 and first motor 2 needs to be restored, and the torque compensation of second motor 14 needs to be canceled so that the entire system can smoothly transition to the new gear drive state.

[0094] Specifically, the VCU first controls the first motor 2 to gradually reduce its compensation torque until it reaches zero. In the first step, the first motor 2 applied a compensation torque opposite to that of the engine 1 (usually a negative value). Now, the VCU instructs the first motor 2 to gradually approach zero with the compensation torque in a linear or gradual manner. For example, if the compensation torque is -100 Nm, the VCU can reduce it to 0 within 100 milliseconds at a rate of 1000 Nm per second. A linear reduction avoids sudden torque changes.

[0095] At the same time, the ECU (Engine Electronic Control Unit) sends a command to the vehicle controller of engine 1 to restore engine 1 to output the required torque.

[0096] It should be noted that the torque recovery of engine 1 also requires a process, because the torque response of engine 1 is slower than that of the first motor 2 (usually requiring tens to hundreds of milliseconds). Therefore, the VCU needs to coordinate the rate of torque reduction of the first motor 2 and the rate of torque increase of engine 1 to make the net torque on the input shaft 3 change smoothly.

[0097] Simultaneously, the VCU controls the second motor 14 to gradually restore its output torque to the target drive torque. In the first step, the second motor 14 added an additional torque ΔTp. Now, the VCU instructs the second motor 14 to gradually remove this additional torque, returning the output torque of the second motor 14 to the normal value allocated according to the driver's needs. The removal of the additional torque ΔTp from the second motor 14 is also done linearly or gradually to avoid sudden changes in wheel torque.

[0098] When the compensation torque of the first motor 2 returns to zero, the engine 1 reaches the required torque, and the additional torque of the second motor 14 returns to zero, the shifting process ends, and the system enters the stable operating state of the second gear.

[0099] The following describes the downshifting process using the example of a vehicle switching from second gear (high gear) to first gear (low gear) in parallel drive mode or engine direct drive mode.

[0100] Step 1: In response to the downshift command, control the second motor 14 to increase its output torque to compensate for the loss of wheel power during the shift process; at the same time, control the first motor 2 to apply a compensation torque in the opposite direction to the output torque of the engine 1 so that the net load torque on the input shaft 3 is reduced to zero.

[0101] Step 2: After the net load torque returns to zero, control the shift actuator to drive synchronizer 8 to disengage from the driven gear corresponding to the current gear, so that synchronizer 8 is in neutral.

[0102] Step 3: Control the first motor 2 to adjust its speed, and increase the speed of the input shaft 3 from the speed corresponding to the current gear to the speed corresponding to the target gear; when the difference between the actual speed of the input shaft 3 and the speed corresponding to the target gear is less than a preset threshold, control the shift actuator to drive the synchronizer 8 to engage with the first gear driven gear 6.

[0103] Step 4: Control the first motor 2 to gradually reduce the compensation torque until it returns to zero, and control the engine 1 to restore the required output torque; at the same time, control the second motor 14 to gradually restore its output torque to the target drive torque.

[0104] The clutchless hybrid transmission gear shifting method provided in this embodiment has the following significant advantages: First, the second motor 14 adjusts its output torque to precisely compensate for the loss of driving or braking force due to the unloading of engine 1 and the first motor 2, ensuring that the total torque of the wheels remains continuous throughout the shift, completely eliminating the feeling of power interruption in traditional shifting. Second, in the third step, the wide speed range and high dynamic response capability of the first motor 2 are utilized to quickly increase or decrease the speed of the input shaft 3 from the current gear synchronization value to the target gear synchronization value, overcoming the difficulty of synchronization in existing clutchless solutions. Third, since the first motor 2 has achieved precise speed adjustment, the synchronizer 8 engages with the driven gear of the target gear at extremely low speed differences. The synchronizer 8 locking ring requires almost no friction, avoiding gear grinding and shifting shock, resulting in a smooth and shock-free shift. Fourth, this method eliminates the traditional clutch and its wear parts, while significantly reducing the frictional load on the synchronizer 8, fundamentally solving problems such as clutch burning and synchronizer 8 wear, and improving the reliability and durability of the transmission system.

[0105] It should be noted that the terms "one implementation," "embodiment," "exemplary embodiment," and "some embodiments" used in the specification indicate that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Moreover, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in conjunction with other embodiments, whether explicitly described or not, is within the knowledge scope of those skilled in the art.

[0106] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0107] The above embodiments are merely preferred embodiments provided to fully illustrate this application, and the scope of protection of this application is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on this application are all within the scope of protection of this application.

Claims

1. A clutchless hybrid transmission assembly, characterized in that, It includes an engine (1), a first motor (2), a second motor (14), an input shaft (3), an intermediate shaft (9), a synchronizer (8), a differential assembly (11), a speed-lifting gear pair (17), a gear set, and a shifting actuator; The output end of the engine (1) is connected to the input shaft (3), and the output shaft of the first motor (2) is connected to the input shaft (3) through a speed-increasing gear pair (17). The gear set is provided in two sets. Each gear set includes a corresponding driving gear and a driven gear. The driving gear is installed on the input shaft (3), and the driven gear is installed on the intermediate shaft (9). The synchronizer (8) is provided on the intermediate shaft (9) and located between the two gear sets. The second motor (14) is connected to the intermediate shaft (9) via a reduction gear pair (15), and the differential assembly (11) is connected to the intermediate shaft (9) via a reduction gear set. The shifting actuator is used to drive the synchronizer (8) to slide axially along the intermediate shaft (9) so that it engages or disengages with the engagement gear ring of the driven gear in different gear positions.

2. The clutchless hybrid transmission assembly according to claim 1, characterized in that, The speed-increasing gear pair (17) includes a first speed-increasing gear and a second speed-increasing gear. The first speed-increasing gear is coaxially mounted on the input shaft (3), and the second speed-increasing gear is coaxially mounted on the output shaft of the first motor (2). The first speed-increasing gear and the second speed-increasing gear mesh with each other.

3. The clutchless hybrid transmission assembly according to claim 1, characterized in that, The two sets of gear sets are the first gear set and the second gear set, respectively; The first gear set includes a first gear drive gear (4) and a first gear driven gear (6), and the second gear set includes a second gear drive gear (5) and a second gear driven gear (7). The first gear drive gear (4) and the second gear drive gear (5) are mounted on the input shaft (3), and the first gear driven gear (6) and the second gear driven gear (7) are mounted on the intermediate shaft (9). The first gear drive gear (4) and the first gear driven gear (6) mesh with each other, and the second gear drive gear (5) and the second gear driven gear (7) mesh with each other.

4. The clutchless hybrid transmission assembly according to claim 1, characterized in that, The reduction gear pair (15) includes a first reduction gear and a second reduction gear. The first reduction gear is mounted on the output shaft of the second motor (14), and the second reduction gear is mounted on the intermediate shaft (9). The first reduction gear and the second reduction gear mesh with each other.

5. A clutchless hybrid transmission assembly according to claim 1, characterized in that, The reduction gear set includes a main reduction drive gear (10) and a main reduction driven gear (12). The main reduction drive gear (10) is mounted on the intermediate shaft (9). The main reduction driven gear (12) is provided on the differential assembly (11). The main reduction drive gear (10) and the main reduction driven gear (12) mesh with each other.

6. A clutchless hybrid transmission assembly according to claim 1, characterized in that, The differential assembly (11) is provided with an output half-shaft (13), which is connected to the wheel.

7. A clutchless hybrid transmission assembly according to claim 1, characterized in that, The system includes a vehicle controller, and the first motor (2), the gear shifting actuator, and the second motor (14) are respectively connected to the vehicle controller via signals.

8. A method for gear shifting in a clutchless hybrid transmission assembly, the method being used to control the clutchless hybrid transmission assembly according to any one of claims 1-7 to perform gear shifting, characterized in that, Includes the following steps: Step 1: In response to the gear shifting command, control the second motor (14) to adjust its output torque to compensate for the wheel power loss during the gear shifting process; at the same time, control the first motor (2) to apply a compensation torque opposite to the output torque of the engine (1) so that the net load torque on the input shaft (3) is reduced to zero. Step 2: After the net load torque is reduced to zero, control the shift actuator to drive the synchronizer (8) to separate from the driven gear corresponding to the current gear, so that the synchronizer (8) is in the neutral position; Step 3: Control the first motor (2) to adjust its speed, increase or decrease the speed of the input shaft (3) from the first synchronous speed corresponding to the current gear to the second synchronous speed corresponding to the target gear, and control the shifting actuator to drive the synchronizer (8) to engage with the driven gear corresponding to the target gear; Step 4: Control the first motor (2) to gradually reduce the compensation torque until it returns to zero, and control the engine (1) to restore the output torque required; at the same time, control the second motor (14) to gradually restore its output torque to the target drive torque.

9. A method for shifting gears in a clutchless hybrid transmission assembly according to claim 8, characterized in that, In the third step, when the first motor (2) adjusts its speed, the engine (1) is controlled to cut off oil or output small torque to reduce the resistance from the engine (1) when the first motor (2) adjusts its speed.

10. A method for shifting gears in a clutchless hybrid transmission assembly according to claim 8, characterized in that, In the third step, when the difference between the actual rotational speed of the input shaft (3) and the second synchronous rotational speed is within the preset threshold and remains stable for a preset time, the shifting actuator is controlled to drive the synchronizer (8) to engage with the driven gear corresponding to the target gear.

11. A method for shifting gears in a clutchless hybrid transmission assembly according to claim 8, characterized in that, In the fourth step, the compensation torque of the first motor (2) is reduced in a linear or gradual manner.

12. The method for shifting gears in a clutchless hybrid transmission assembly according to claim 8, characterized in that, In the third step, when the difference between the first synchronous speed and the second synchronous speed of the input shaft (3) is less than a preset threshold, the shifting actuator is controlled to drive the synchronizer (8) to engage with the driven gear corresponding to the target gear.

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