Medium-duty truck hybrid transmission

Abstract

The hybrid transmission for medium-duty trucks includes a shift assembly with two-speed transmission, an engine, an output shaft connected to the drive axle, an auxiliary motor connected to the crankshaft end of the engine, a main drive motor, and a reduction gear set connected to the main drive motor. Its distinguishing feature is that the crankshaft end is connected to the shift assembly via a clutch, and the reduction gear set and the shift assembly are respectively engaged with the output shaft. In this invention, the auxiliary motor can be used for both driving and generating electricity to extend the electric drive range. It improves power output efficiency in high-load scenarios such as climbing, getting out of trouble, and acceleration, reduces fuel consumption, and is compatible with battery range extension. It achieves dynamic coupling of multiple modes including power generation, driving, and energy recovery, improving the road adaptability of medium-duty trucks and balancing low-speed pure electric drive with high-speed fuel economy.

Description

Technical Field

[0001] This utility model relates to a hybrid transmission for medium-duty trucks, belonging to the field of hybrid transmission technology. Background Technology

[0002] A dual-motor hybrid transmission is a technology that uses two electric motors and an integrated transmission to achieve a hybrid power system. This design allows the vehicle to choose between electric motors or an internal combustion engine to drive it as needed, resulting in higher energy conversion efficiency. Currently, hybrid power is becoming increasingly common in the commercial vehicle sector. Depending on the connection method of the hybrid system, it is mainly divided into three structural configurations: series, parallel, and series-parallel. Based on the architecture, it is further divided into P0, P1, P2, P2.5, P3, P4, and P5. In the P1 architecture, the electric motor is placed before the transmission, mounted on the engine crankshaft, before the K0 clutch; the main drive motor is located at the output end of the transmission, connected by a belt, gears, or coaxially with the engine, and outputs from the same source. P1+P3 is the mainstream architecture in dual-motor solutions. P1+P3 is a simple and efficient hybrid architecture. When the clutch is disengaged, the engine drives motor P1 to generate electricity, and motor P3 drives the wheels through a gear set, achieving pure electric mode. When the clutch is engaged, the engine drives the wheels simultaneously through the transmission mechanism and motor P3, achieving parallel mode. The transmission mechanism is simple, usually without multi-speed transmissions, requiring only a single-speed reducer, reducing costs. Meanwhile, the P3 drive motor is a high-power motor, providing good acceleration performance in pure electric mode. Its simple structure makes axial layout relatively easy, adaptable to vehicles of all levels. The motor is placed after the transmission mechanism, far from the engine, which to some extent avoids the jerking problem caused by electromechanical coupling. However, the P1+P3 dual-motor solution also has the following drawbacks:

[0003] 1. In hybrid mode, only one motor participates in driving, and only the other motor is used to generate electricity to charge the battery pack, resulting in insufficient power in high-load scenarios such as heavy-load climbing and getting out of trouble.

[0004] 2. Commercial vehicles operate in harsh and complex road conditions with rapidly changing operating conditions. Without multi-speed transmissions, their adaptability to road conditions in medium and heavy-duty trucks needs improvement. Utility Model Content

[0005] The hybrid transmission for medium-duty trucks provided by this utility model has an auxiliary motor that can be used for both driving and generating electricity to extend the range of electric drive. It improves power output efficiency, reduces fuel consumption, and is compatible with battery range extension in high-load scenarios such as climbing, getting out of trouble, and acceleration. It realizes dynamic coupling of multiple modes of power generation, driving, and energy recovery, improves the road adaptability of medium-duty trucks, and takes into account both low-speed pure electric drive and high-speed fuel economy.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0007] A medium-duty truck hybrid transmission includes a shift assembly with two-speed shifting function, an engine, an output shaft connected to a drive axle, an auxiliary motor connected to the crankshaft end of the engine, a main drive motor, and a reduction gear set connected to the main drive motor. The characteristic is that the crankshaft end is connected to the shift assembly via a clutch, and the reduction gear set and the shift assembly are respectively engaged with the output shaft.

[0008] Preferably, the clutch includes a clutch sleeve that is slidably mounted on the crankshaft end along the axial direction and an engagement gear fixed on the input end of the shift assembly and corresponding to the clutch sleeve. The clutch sleeve is located to the left of the engagement gear, and the clutch sleeve moves to the right to engage with the engagement gear to connect the engine and the shift assembly.

[0009] Preferably, a constant mesh gear is coaxially fixed at the crankshaft end, and the constant mesh gear meshes with the motor shaft of the auxiliary motor.

[0010] Preferably, the shift assembly includes a shift shaft coaxially aligned with the crankshaft end, a shift sleeve slidably axially meshing with the shift shaft, a first-gear drive gear rotatably mounted on the shift shaft, a second-gear drive gear rotatably mounted on the shift shaft, an intermediate shaft parallel to the shift shaft, a first-gear driven gear coaxially fixed on the intermediate shaft and meshing with the first-gear drive gear, a second-gear driven gear coaxially fixed on the intermediate shaft and meshing with the second-gear drive gear, the shift sleeve being located between the first-gear drive gear and the second-gear drive gear, the shift sleeve moving to the left engaging with the first-gear drive gear, and moving to the right engaging with the second-gear drive gear, the engaging gear being coaxially fixed to the front end of the shift shaft.

[0011] Preferably, a second constant mesh gear is coaxially fixed on the intermediate shaft, and an output gear that meshes with the second constant mesh gear is coaxially fixed on the output shaft.

[0012] Preferably, the reduction gear set includes a reduction shaft parallel to the output shaft, a first reduction gear coaxially fixed on the reduction shaft and meshing with the motor shaft of the main drive motor, and a second reduction gear coaxially fixed on the reduction shaft and meshing with the output gear.

[0013] The beneficial effects of this utility model are:

[0014] This utility model discloses a hybrid gearbox for medium-duty trucks. An auxiliary motor is connected to the crankshaft end, and the main drive motor is connected to a reduction gear set. The crankshaft end is connected to a shift assembly via a clutch. The reduction gear set and shift assembly are respectively engaged with the output shaft. When the clutch is engaged, the engine, auxiliary motor, and main drive motor work together to form a hybrid mode, suitable for heavy-duty conditions. This improves the power output efficiency of medium-duty trucks during heavy-duty climbing and off-road maneuvers, meeting the driving needs of medium-duty trucks under extreme conditions. If the battery power is insufficient, the auxiliary motor stops driving. The engine, while working with the main drive motor, simultaneously drives the auxiliary motor to charge the battery. The auxiliary motor can be used for driving or generating electricity to extend the electric drive range. The output speed is adjusted through the shift assembly to meet the driving needs of medium-duty trucks for acceleration and overtaking under heavy loads. When the clutch is disengaged, only the main drive motor drives, forming a pure electric mode, suitable for light-duty trucks. Under normal operating conditions, if the battery power is insufficient, the engine starts to drive the auxiliary motor to generate electricity and charge the battery, thus extending the electric drive range. Under reverse drive conditions such as downhill, the clutch is disengaged, and the reverse drive force of the drive wheels is transmitted to the output shaft, which drives the main drive motor to generate electricity and charge the battery through the reduction gear set, realizing energy recovery. The auxiliary motor is set at the crankshaft end to realize efficient start-stop, power generation and torque assistance. The main drive motor is directly driven to provide strong electric drive force and supports low-speed pure electric drive and energy recovery. Through the coordinated control of the dual motors, the engine working range is dynamically optimized to reduce idling loss. In high-load scenarios such as climbing, getting out of trouble and acceleration, the power output efficiency is improved, fuel consumption is reduced and battery range extension is compatible. The dynamic coupling of multiple modes of power generation, drive and energy recovery is realized to improve the road adaptability of medium trucks and take into account both low-speed pure electric drive and high-speed fuel economy. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the transmission of the medium-duty truck hybrid gearbox of this utility model.

[0016] Figure 2 This is a schematic diagram of the transmission when the hybrid transmission of a medium-duty truck is in first gear driving mode.

[0017] Figure 3 This is a schematic diagram of the transmission of a medium-duty truck hybrid gearbox in pure electric mode. Detailed Implementation

[0018] The following is combined Figures 1-3 The embodiments of this utility model will be described in detail below.

[0019] A medium-duty truck hybrid transmission includes a shift assembly 1 with two-speed shifting function, an engine 2, an output shaft 3 connected to a drive axle, an auxiliary motor 4 connected to the crankshaft end 20 of the engine 2, a main drive motor 5, and a reduction gear set 6 connected to the main drive motor 5. The characteristic is that the crankshaft end 20 is connected to the shift assembly 1 through a clutch 7, and the reduction gear set 6 and the shift assembly 1 are respectively engaged with the output shaft 3.

[0020] The hybrid transmission for medium-duty trucks described above has an auxiliary motor 4 connected to the crankshaft end 20, a main drive motor 5 connected to the reduction gear set 6, and the crankshaft end 20 connected to the shift assembly 1 via a clutch 7. The reduction gear set 6 and the shift assembly 1 are respectively engaged with the output shaft 3. When the clutch 7 is engaged, the engine 2, auxiliary motor 4, and main drive motor 5 drive together to form a hybrid mode, suitable for heavy-duty conditions, improving the power output efficiency of medium-duty trucks when climbing hills and getting out of trouble, and meeting the driving needs of medium-duty trucks under extreme conditions. If the battery power is insufficient, the auxiliary motor 4 stops driving, and the engine 2 drives the auxiliary motor 5 to charge the battery while driving together with the main drive motor 5. The auxiliary motor 4 can be used for driving or for generating electricity to extend the electric drive range, and the output speed is adjusted through the shift assembly 1 to meet the driving needs of medium-duty trucks for acceleration and overtaking under heavy loads. When the clutch is disengaged, only the main drive motor 5 drives, forming a pure electric mode. The system is designed for light-load conditions. When the battery is low, the engine 2 starts to drive the auxiliary motor 4 to generate electricity and charge the battery for electric drive range extension. In reverse drive conditions such as downhill driving, the clutch is disengaged, and the reverse drive force of the drive wheels is transmitted to the output shaft 3, which then drives the main drive motor 5 to generate electricity and charge the battery via the reduction gear set 6, thus achieving energy recovery. The auxiliary motor 4 is located at the crankshaft end to achieve efficient start-stop, power generation, and torque assistance. The main drive motor 5 directly drives the output shaft 3 to provide strong electric drive force and supports low-speed pure electric drive and energy recovery. Through the coordinated control of the dual motors, the engine operating range is dynamically optimized to reduce idling losses. In high-load scenarios such as climbing, getting out of trouble, and acceleration, the power output efficiency is improved, fuel consumption is reduced, and battery range extension is compatible. This achieves dynamic coupling of multiple modes of power generation, drive, and energy recovery, improving the road adaptability of the medium-duty truck and balancing low-speed pure electric drive with high-speed fuel economy.

[0021] The clutch 7 includes a clutch sleeve 71 slidably mounted on the crankshaft end along the axial direction and an engagement gear 72 fixed on the input end of the shift assembly 1 and corresponding to the clutch sleeve 71. The clutch sleeve 71 is located to the left of the engagement gear 72. The clutch sleeve 71 moves to the right and engages with the engagement gear 72 to connect the engine and the shift assembly. This sliding sleeve clutch is easy to operate. The engine and auxiliary motor can only participate in driving when the clutch sleeve 71 is engaged with the engagement gear 72. The sliding of the clutch sleeve 71 enables the conversion between pure electric drive and hybrid drive, making operation simple and convenient.

[0022] The engine shaft crank end is coaxially fixed with a constant mesh gear 21, which meshes with the motor shaft of the auxiliary motor 4. If the battery power is insufficient during driving, the engine 2 drives the constant mesh gear 21 to rotate, thereby driving the auxiliary motor 4 to generate electricity to charge the battery, thus extending the electric drive range during driving.

[0023] The shift assembly 1 includes a shift shaft 11 coaxially aligned with the crankshaft end 20, a shift sleeve 12 slidably slidably meshing with the shift shaft 11, a first-gear drive gear 13 rotatably mounted on the shift shaft 11, a second-gear drive gear 14 rotatably mounted on the shift shaft 11, an intermediate shaft 15 parallel to the shift shaft 11, a first-gear driven gear 16 coaxially fixed on the intermediate shaft 15 and meshing with the first-gear drive gear 13, and a second-gear driven gear 17 coaxially fixed on the intermediate shaft 15 and meshing with the second-gear drive gear 14. The shift sleeve 12 is located between the first-gear drive gear 13 and the second-gear drive gear 14. The shift sleeve 12 moves to the left to engage with the first-gear drive gear 13 and moves to the right to engage with the second-gear drive gear 14. The engaging gear 72 is coaxially fixed to the front end of the shift shaft 11. The engine can only participate in driving when the clutch 7 is engaged. The shift sleeve 12 can be moved to form a gear change to meet the driving demand for vehicle acceleration under heavy load conditions. When the shift sleeve 12 moves to the left and engages with the first gear drive gear 13, the power on the shift shaft 11 is transmitted to the intermediate shaft 15 through the first gear drive gear 13 and the first gear driven gear 16, and then to the output shaft 3 through the intermediate shaft 15. When the shift sleeve 12 moves to the left and engages with the second gear drive gear 14, the power on the shift shaft 11 is transmitted to the intermediate shaft 15 through the second gear drive gear 14 and the second gear driven gear 17, and then to the output shaft through the intermediate shaft 15.

[0024] In this configuration, a second constant mesh gear 18 is coaxially fixed on the intermediate shaft 15, and an output gear 31, which meshes with the second constant mesh gear 18, is coaxially fixed on the output shaft 3. The power on the intermediate shaft 15 is transmitted to the output shaft 3 through the engagement of the second constant mesh gear 18 and the output gear 31.

[0025] The reduction gear set 6 includes a reduction shaft 61 parallel to the output shaft 3, a first reduction gear 62 coaxially fixed to the reduction shaft 61 and meshing with the motor shaft of the main drive motor, and a second reduction gear 63 coaxially fixed to the reduction shaft 62 and meshing with the output gear 31. The reduction gear set 6, through the meshing of the first reduction gear 62 with the motor shaft of the main drive motor 5 and the meshing of the second reduction gear 63 with the output gear 31, reduces the power of the main drive motor 5 and transmits it to the output shaft 3, thus forming pure electric power.

[0026] The following details the driving methods of the above-described medium-duty hybrid transmission under different operating conditions:

[0027] Under heavy load conditions, the clutch 7 is engaged, and the engine 2, auxiliary motor 4, and main drive motor 5 work together to form a hybrid mode. When the shift sleeve 12 engages with the first gear drive gear 13, it forms the first gear drive of the hybrid mode. When the shift sleeve 12 engages with the second gear drive gear 14, it forms the second gear drive of the hybrid mode. The second gear drive of the hybrid mode is suitable for overtaking under heavy load conditions. When the battery power is insufficient under heavy load conditions, the auxiliary motor 4 stops driving. The engine 2 and the main drive motor 5 work together to drive the auxiliary motor 4 to generate electricity to charge the battery, forming a hybrid range extender mode.

[0028] Under light load conditions, the clutch 7 is disengaged, and only the main drive motor 5 is used for driving, forming a pure electric mode. When the battery power is insufficient under light load conditions, the engine 2 is started, and the engine drives the auxiliary motor 4 to generate electricity to charge the battery, forming a pure electric range extender mode.

[0029] The technical solutions of the embodiments of this utility model have been fully described above with reference to the accompanying drawings. It should be noted that the described embodiments are only a part of the embodiments of this utility model. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

Claims

1. A medium hybrid transmission, comprising a gear shifting assembly having a two-gear shifting function, an engine, an output shaft connected with a drive axle, an auxiliary motor connected with a crankshaft end of the engine, a main drive motor, and a reduction gear set connected with the main drive motor, characterized in that: The crankshaft end is connected to the shift assembly via a clutch, and the reduction gear set and the shift assembly are respectively engaged with the output shaft.

2. The mid-cab hybrid transmission of claim 1, wherein: The clutch includes a clutch sleeve that is slidably mounted on the crankshaft end along the axial direction and an engagement gear that is fixed on the input end of the shift assembly and corresponds to the clutch sleeve. The clutch sleeve is located to the left of the engagement gear. The clutch sleeve moves to the right and engages with the engagement gear to connect the engine and the shift assembly.

3. The mid-card hybrid transmission of claim 1, wherein: The crankshaft end is coaxially fixed with a constant mesh gear, which meshes with the motor shaft of the auxiliary motor.

4. The mid-card hybrid transmission of claim 2, wherein: The shift assembly includes a shift shaft coaxially aligned with the crankshaft end, a shift sleeve slidably slidably meshing with the shift shaft, a first-gear drive gear rotatably mounted on the shift shaft, a second-gear drive gear rotatably mounted on the shift shaft, an intermediate shaft parallel to the shift shaft, a first-gear driven gear coaxially fixed on the intermediate shaft and meshing with the first-gear drive gear, a second-gear driven gear coaxially fixed on the intermediate shaft and meshing with the second-gear drive gear, the shift sleeve being located between the first-gear drive gear and the second-gear drive gear, the shift sleeve moving to the left engaging with the first-gear drive gear, and moving to the right engaging with the second-gear drive gear, the engaging gears being coaxially fixed to the front end of the shift shaft.

5. The mid-card hybrid transmission of claim 4, wherein: A second constant mesh gear is coaxially fixed on the intermediate shaft, and an output gear that meshes with the second constant mesh gear is coaxially fixed on the output shaft.

6. The mid-card hybrid transmission of claim 5, wherein: The reduction gear set includes a reduction shaft parallel to the output shaft, a first reduction gear coaxially fixed on the reduction shaft and meshing with the motor shaft of the main drive motor, and a second reduction gear coaxially fixed on the reduction shaft and meshing with the output gear.

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