Series hybrid power transmission system without power interruption and tractor

Abstract

The invention relates to a series hybrid power transmission system without power interruption and a tractor, and belongs to the technology of hybrid power transmission systems of tractors, and the series hybrid power transmission system comprises an auxiliary power unit, a first power unit and a second power unit, the first motor is connected with a second input shaft; the first offset gear mechanism is arranged between the first input shaft and the second input shaft; the first gear shifting mechanism is hollowly sleeved on the first input shaft; a main driving force unit including: a second motor connected to a third input shaft; a transfer shaft; an output shaft; the transfer shaft gear shifting mechanism comprises a first transfer gear pair, a second transfer gear pair and a second gear shifting mechanism, and the second gear shifting mechanism is used for adjusting the joint of the transfer shaft and the first transfer gear pair or the second transfer gear pair; and the first gear shifting mechanism is used for adjusting joint of the first offset gear mechanism and the first input shaft or the first transfer gear pair, power continuity is maintained in the whole gear shifting process, and loss of traction force caused by power interruption is avoided.

Description

Technical Field

[0001] This application relates to the field of tractor hybrid powertrain technology, and particularly to a series hybrid powertrain system with no power interruption and a tractor. Background Technology

[0002] In the field of agricultural machinery, tractors, as important working equipment, rely heavily on their transmission systems, which directly determine their operational efficiency, fuel economy, and operator comfort. For a long time, traditional tractors have primarily used fully automatic transmissions or hydraulic continuously variable transmissions (CVTs) as their core transmission technologies. These technologies have played a crucial role in enabling power transmission and gear shifting in tractors. However, with the increasing demands for continuity and efficiency in modern agriculture, the limitations of these traditional technologies have become increasingly apparent.

[0003] Full-power automatic transmissions achieve gear shifting by precisely controlling the engagement and disengagement of the clutch through a hydraulic system. During gear shifting, the system needs to maintain engine power, completing gear changes through the engagement and disengagement of a wet clutch. Its core principle is to achieve smooth gear shifting without power interruption through the complex control of the wet clutch and intelligent electro-hydraulic control system. This system is costly and faces significant control technology bottlenecks. Hydraulic continuously variable transmissions (CVTs) achieve continuously variable speeds by adjusting hydraulic flow, but the efficiency loss of hydraulic components is significant, leading to reduced overall transmission efficiency and increased fuel consumption. Furthermore, the complexity of the hydraulic system increases system weight and cost, and issues such as hydraulic oil temperature control and leakage increase maintenance difficulty.

[0004] Therefore, these systems are highly complex, and it is difficult for China to overcome the technological barriers in the short term. This results in domestic tractor automatic transmissions being severely constrained by foreign monopolistic technology, leading to high overall costs. Furthermore, with the rapid development of new energy electrification technology in recent years, electronic continuously variable transmission (eCVT) control technology based on the series hybrid principle has emerged. This technology involves a series-connected generator with continuously variable speed for efficient power generation. The engine and generator are mechanically completely decoupled from the traction drive output, and the drive motor independently employs a two-speed drive structure. However, during tractor operation, gear shifting by the drive motor will interrupt the traction power, thus affecting the continuity and efficiency of tractor operation. Summary of the Invention

[0005] This application provides a series hybrid power transmission system and tractor with no power interruption, in order to solve the problem in the related technology that the power interruption is inevitable during gear shifting, resulting in the instantaneous loss of wheel-side traction, which seriously affects the continuity and efficiency of the tractor under high-load working conditions.

[0006] In a first aspect, a series hybrid power transmission system with no power interruption is provided, comprising: an auxiliary power unit including: an engine connected to a first input shaft; a first motor connected to a second input shaft; a first bias gear mechanism disposed between the first and second input shafts; a first shifting mechanism loosely fitted onto the first input shaft; a main drive unit including: a second motor connected to a third input shaft; a transfer shaft connected to the third input shaft by a second bias gear mechanism; an output shaft; and a transfer shaft gear shifting mechanism including a first transfer shaft gear mechanism. The system includes a gear pair, a second intermediate gear pair, and a second shifting mechanism. The first intermediate gear pair is loosely fitted at both ends onto the first input shaft and the intermediate shaft, respectively, and is fixedly connected to the output shaft. One end of the second intermediate gear pair is fixed to the output shaft, and the other end is loosely fitted onto the intermediate shaft. The second shifting mechanism is used to adjust the engagement between the intermediate shaft and the first intermediate gear pair or the second intermediate gear pair. The first shifting mechanism is used to adjust the engagement between the first offset gear mechanism and the first input shaft or the first intermediate gear pair.

[0007] In some embodiments, the first bias gear mechanism includes a first driving bias gear and a first driven bias gear meshing with each other, wherein the first driving bias gear is fixedly connected to the second input shaft, and the first driven bias gear is loosely fitted on the first input shaft.

[0008] In some embodiments, the second bias gear mechanism includes a second active bias gear and a second driven bias gear that mesh with each other. The second active bias gear is fixedly sleeved on the third input shaft, and the second driven bias gear is fixedly sleeved on the intermediate shaft.

[0009] In some embodiments, the first shifting mechanism is loosely fitted onto the first input shaft to adjust the engagement of the first driven bias gear with the first input shaft or with the first intermediate gear pair.

[0010] In some embodiments, the first intermediate gear pair includes: a first driving gear, which is loosely fitted on the first input shaft; a first intermediate driving gear, which is loosely fitted on the intermediate shaft; and a first output gear, which is fixedly fitted on the output shaft and simultaneously meshes with the first driving gear and the first intermediate driving gear. The first shifting mechanism is used for engaging the first driven bias gear with the first input shaft or with the first driving gear.

[0011] In some embodiments, the first shifting mechanism is embedded in the first driven bias gear on the first input shaft.

[0012] In some embodiments, a hollow shaft is loosely fitted around the first input shaft, the first shifting mechanism is disposed on the hollow shaft, and the hollow shaft is connected to the first driven bias gear, with the first driving gear loosely fitted on the hollow shaft.

[0013] In some embodiments, the second intermediate gear pair includes: a second intermediate drive gear, which is loosely fitted on the intermediate shaft; a second output gear, which is fixedly fitted on the output shaft and meshes with the second intermediate drive gear; and a second shifting mechanism for adjusting the engagement of the intermediate shaft with the first intermediate drive gear or with the second intermediate drive gear.

[0014] In some embodiments, the second shifting mechanism is slidably connected to the transfer shaft and located between the first transfer drive gear and the second transfer drive gear.

[0015] In a second aspect, a tractor is provided, comprising: the tractor including the uninterrupted series hybrid powertrain as described in any of the first aspects.

[0016] The beneficial effects of the technical solution provided in this application include: This application provides a series hybrid power transmission system and tractor with no power interruption. By adjusting the engagement or disengagement of the first bias gear mechanism and the second input shaft through the first shifting mechanism, dynamic switching of the power path is achieved: When the second motor shifts gears, the first shifting mechanism quickly shifts gears so that the first motor provides power compensation through the first bias gear mechanism and the first intermediate gear pair, ensuring continuous output of wheel-side traction force; at the same time, the second shifting mechanism of the intermediate shaft gear shifting mechanism switches the engagement state of the first intermediate gear pair and the second intermediate gear pair to complete the gear shift, thereby maintaining power continuity throughout the shifting process and avoiding the loss of traction force caused by power interruption in traditional systems. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the overall structure of the first gear shifting mechanism in an embodiment of this application, used to illustrate the first connection state of the first gear shifting mechanism. Figure 2 This application provides an overall structural schematic diagram illustrating the second connection state of the first shifting mechanism.

[0019] In the diagram: 1. Engine; 10. First input shaft; 100. Hollow shaft; 2. First motor; 20. Second input shaft; 3. First bias gear mechanism; 30. First driving bias gear; 31. First driven bias gear; 4. First shifting mechanism; 5. Second motor; 50. Third input shaft; 6. Intermediate shaft; 60. Second bias gear mechanism; 600. Second driving bias gear; 601. Second driven bias gear; 7. Output shaft; 8. Intermediate shaft gear shifting mechanism; 80. First intermediate gear pair; 800. First driving gear; 801. First intermediate driving gear; 802. First output gear; 81. Second intermediate gear pair; 810. Second intermediate driving gear; 811. Second output gear; 82. Second shifting mechanism; 820. First position; 821. Second position; 822. Third position. Detailed Implementation

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

[0021] This application provides a series hybrid power transmission system and tractor with no power interruption, which can solve the problem in the related technology that the power interruption is inevitable during the gear shifting process, resulting in the instantaneous loss of wheel-side traction, which seriously affects the continuity and efficiency of the tractor under high-load working conditions.

[0022] Example 1 Reference Figure 1-2 A series hybrid power transmission system with no power interruption is disclosed, comprising: an auxiliary power unit and a main drive unit. The auxiliary power unit includes: an engine 1, a first motor 2, a first bias gear mechanism 3, and a first shift mechanism 4. The output end of the engine 1 is connected to a first input shaft 10. The output end of the first motor 2 is connected to a second input shaft 20. The first bias gear mechanism 3 is disposed between the first input shaft 10 and the second input shaft 20. Finally, the first shift mechanism 4 is loosely fitted onto the first input shaft 10.

[0023] The main drive unit includes a second motor 5, a central shaft 6, an output shaft 7, and a central shaft gear shifting mechanism 8. The second motor 5 is connected to a third input shaft 50, and a second offset gear mechanism 60 connects the central shaft 6 and the third input shaft 50. The output shaft 7 is arranged parallel to the central shaft 6. The central shaft gear shifting mechanism 8 connects the central shaft 6 and the output shaft 7. The central shaft gear shifting mechanism 8 includes a first central gear pair 80, a second central gear pair 81, and a second shifting mechanism 82. The first central gear... The first intermediate gear pair 80 is loosely fitted at both ends onto the first input shaft 10 and the intermediate shaft 6, respectively. The first intermediate gear pair 80 is fixedly connected to the output shaft 7. One end of the second intermediate gear pair 81 is fixed to the output shaft 7, and the other end is loosely fitted onto the intermediate shaft 6. The second shifting mechanism 82 is used to adjust the engagement between the intermediate shaft 6 and the first intermediate gear pair 80 or the second intermediate gear pair 81. The first shifting mechanism 4 is used to adjust the engagement between the first bias gear mechanism 3 and the first input shaft 10 or the first intermediate gear pair 80.

[0024] In this application, the engine 1 outputs power via the first input shaft 10, and the first motor 2 is coupled to the first bias gear mechanism 3 via the second input shaft 20. When the first bias gear mechanism 3 is engaged with the first input shaft 10, part of the power from the engine 1 is transmitted to the second input shaft 20 via the first bias gear mechanism 3; when the first bias gear mechanism 3 is disengaged from the first input shaft 10, the power is directly transmitted from the engine 1 via the first input shaft 10. The second motor 5 serves as the main driving force source and is connected to the third input shaft 50. A second bias gear mechanism 60 is provided between the intermediate shaft 6 and the third input shaft 50 to achieve speed reduction and torque increase of the motor power. The intermediate shaft gear shifting mechanism 8 connects the intermediate shaft 6 and the output shaft 7, and controls the engagement of the intermediate shaft 6 with the first intermediate gear pair 80 or the second intermediate gear pair 81 through the second shifting mechanism 82, and adjusts the engagement of the first bias gear mechanism 3 with the first input shaft 10 or the first intermediate gear pair 80 through the first shifting mechanism 4.

[0025] When the main drive unit needs to switch gears, firstly, the first bias gear mechanism 3 is connected to the first input shaft 10 by the first shifting mechanism 4, and the first motor 2 is connected to the engine 1 by bias transmission. This can achieve series linkage for power generation, or parallel linkage for the first motor 2 to assist the PTO output of the engine 1. The first shifting mechanism 4 engages the first bias gear mechanism 3 with the first intermediate gear pair 80. The first motor 2 provides power compensation for the shifting process of the second motor 5 through the transmission of the first bias gear mechanism 3 and the first intermediate gear pair 80. The second motor 5 is unloaded at the same time, and the second shifting mechanism 82 completes the shifting control of the two gears. The power of the first motor 2 is continuously transmitted to the output shaft 7 to ensure that the wheel-side traction force of the second motor 5 is uninterrupted during the shifting process. After the second motor 5 has finished shifting, the first motor 2 is unloaded, the first shifting mechanism 4 is disengaged, and then the first bias gear mechanism 3 is engaged with the first input shaft 10, thereby realizing the series linkage between the engine 1 and the first motor 2, and the second motor 5 resumes the main drive path. This mechanism replaces the physical disengagement of the traditional hydraulic clutch with the rigid engagement of the mechanical structure, transforming the gear shifting process into a seamless switching of the power source. It does not require complex electronic control and relies solely on the precise linkage of the gear mechanism, fundamentally eliminating the root cause of power interruption.

[0026] In series hybrid mode, the second motor 5, the main drive motor, provides wheel-side traction drive. The engine 1 directly provides PTO power output while simultaneously generating electricity in series with the first motor 2 to replenish the power battery. It can also provide some electrical energy directly to the second motor 5 for driving. When the power battery reaches its set limit, the first motor 2 stops generating electricity, thus entering a standby mode.

[0027] In this application, the first bias gear mechanism 3 includes a first driving bias gear 30 and a first driven bias gear 31 that mesh with each other. The first driving bias gear 30 is fixedly connected to the second input shaft 20, and the first driven bias gear 31 is loosely fitted on the first input shaft 10. The first shifting mechanism 4 is loosely fitted on the first input shaft 10 to adjust the engagement of the first driven bias gear 31 with the first input shaft 10 or with the first intermediate gear pair 80.

[0028] In this application, the second bias gear mechanism 60 includes a second driving bias gear 600 and a second driven bias gear 601 that mesh with each other. The second driving bias gear 600 is fixedly sleeved on the third input shaft 50, and the second driven bias gear 601 is fixedly sleeved on the intermediate shaft 6. The second driving bias gear 600, fixed to the third input shaft 50, rotates synchronously with the second motor 5. The second driven bias gear 601, fixed to the intermediate shaft 6, meshes with the second driving bias gear 600, directly transmitting the rotational power of the third input shaft 50 to the intermediate shaft 6. After the intermediate shaft 6 rotates, the connection with the output shaft 7 is adjusted through the intermediate shaft gear shifting mechanism 8 to achieve gear switching.

[0029] In this application, engine 1 can directly provide PTO output through the first input shaft 10. The first shift mechanism 4 includes three control states: when the first shift mechanism 4 engages the first driven bias gear 31 with the first input shaft 10, the first motor 2 is connected to the first input shaft 10 through the first bias gear mechanism 3, and the first motor 2 and engine 1 are connected in series to generate electricity. At the same time, engine 1 can provide PTO output through the first input shaft 10, and the first motor 2 can also provide transient assistance for PTO output; when the first shift mechanism 4 is in neutral, the first motor 2 and the first bias gear mechanism 3 are disengaged and the engine stops; when the first shift mechanism 4 engages the first driven bias gear 31 with the first intermediate gear pair 80, the first motor 2 can provide shift power compensation for the second motor 5, or provide driving power simultaneously with the second motor 5 in gear.

[0030] Furthermore, PTO output often constitutes a large portion of the engine 1's power input under many operating conditions. In some heavy-duty PTO conditions, PTO accounts for more than 70-80% of the engine 1's power input. Only a portion of the engine 1's power is connected in series with the first motor 2 on the first input shaft 10 to generate electricity. A portion of the remaining power from the engine 1, excluding the PTO power output, is converted into electrical energy by the first motor 2 to charge the vehicle's power battery, or some electrical energy is directly supplied to the second motor 5 to participate in wheel-side traction drive.

[0031] Alternatively, in certain light-load PTO (Power To-Drive) operations with the tractor stationary, direct PTO output from engine 1 is inefficient. In this case, the second motor 5 can provide more efficient PTO drive. To improve fuel economy, the first shift mechanism 4 engages to connect the first motor 2 to the first input shaft 10, while the second shift mechanism 82 is in neutral. The transfer shaft 6 can then serve as the output shaft 7 for light-load PTO operations when the tractor is stationary. Engine 1 and the first motor 2 are connected in series to generate electricity efficiently, charging the power battery. A portion of this electricity is used to power the second motor 5 for PTO drive. Once the state of charge (SOC) of the power battery reaches a set high limit, engine 1 and the first motor 2 stop, and the second motor 5 uses the power battery's energy to provide PTO power output. Furthermore, when the onboard power battery is fully charged, engine 1 is off, and the second motor 5 can independently provide pure electric drive for the tractor's wheels. In special situations requiring getting out of trouble, the first motor 2 can shift gears to provide assistance.

[0032] In this application, the first intermediate gear pair 80 includes a first driving gear 800, a first intermediate driving gear 801, and a first output gear 802; the first driving gear 800 is loosely fitted on the first input shaft 10, the first intermediate driving gear 801 is loosely fitted on the intermediate shaft 6, and the first output gear 802 is fixedly fitted on the output shaft 7, and simultaneously meshes with the first driving gear 800 and the first intermediate driving gear 801.

[0033] When the first shifting mechanism 4 engages the first driven bias gear 31 with the first driving gear 800, the first motor 2 provides power compensation for the shifting process of the second motor 5 through the power transmission path of the second input shaft 20 → first driving bias gear 30 → first driven bias gear 31 → first driving gear 800 → first output gear 802 → output shaft 7.

[0034] In this embodiment, the connection method of the first shifting mechanism 4 includes, but is not limited to, loosely fitting the first shifting mechanism 4 onto the first input shaft 10 to adjust the engagement of the first driven bias gear 31 with the first input shaft 10 or with the first intermediate gear pair 80. Specifically, the way the first shifting mechanism 4 is loosely fitted onto the first input shaft 10 includes, but is not limited to, the first shifting mechanism 4 being internally connected to the first driven bias gear 31 on the first input shaft 10. The internal connection between the first shifting mechanism 4 and the first driven bias gear 31 achieves seamless switching of the power path through the internal meshing mechanism: when the first shifting mechanism 4 adjusts the engagement of the first driven bias gear 31 with the first input shaft 10, the power of the first motor 2 is linked with the engine 1 via the first bias gear mechanism 3; when engaged with the first intermediate gear pair 80, the power of the first motor 2 is transmitted to the first intermediate gear pair 80 via the first bias gear mechanism 3, and then drives the output shaft 7 via the main drive unit. This design ensures that the output shaft 7 receives continuous and stable power during the switching process between the second motor 5 and the first motor 2, completely eliminating power interruption and improving transmission response efficiency and smooth operation.

[0035] In some other feasible embodiments of this application, a hollow shaft 100 can be loosely fitted outside the first input shaft 10, with the first shifting mechanism 4 disposed on the hollow shaft 100 and connected to the first driven bias gear 31. The first driving gear 800 is loosely fitted on the hollow shaft 100. By loosely fitting the hollow shaft 100 outside the first input shaft 10, the first shifting mechanism 4 is integrated onto the hollow shaft 100, and the hollow shaft 100 is fixedly connected to the first driven bias gear 31. At the same time, the first driving gear 800 is loosely fitted on the hollow shaft 100, achieving precise and uninterrupted switching of the power path: when the first shifting mechanism 4 moves to engage the first driven bias gear 31 with the first input shaft 10, the power of the first motor 2 is linked with the engine 1 via the first bias gear mechanism 3; when engaged with the first driving gear 800, the power of the first motor 2 is transmitted to the first intermediate gear pair 80 via the first bias gear mechanism 3, and then drives the output shaft 7 through the main driving force unit. This design significantly reduces mechanical interference between the shift mechanism and the first input shaft 10, improves switching response speed and reliability, completely eliminates power interruption, ensures continuous and stable power to the output shaft 7, and optimizes system transmission efficiency and smooth operation.

[0036] In this application, the second intermediate gear pair 81 includes a second intermediate drive gear 810 and a second output gear 811. The second intermediate drive gear 810 is loosely fitted on the intermediate shaft 6, and the second output gear 811 is fixedly fitted on the output shaft 7 and meshes with the second intermediate drive gear 810. A second shifting mechanism 82 is used to adjust the engagement between the intermediate shaft 6 and the first intermediate drive gear 801 or the second intermediate drive gear 810. The second intermediate drive gear 810, loosely fitted on the intermediate shaft 6, can quickly enter the meshing state during gear shifting; the second output gear 811, fixedly fitted on the output shaft 7, ensures that power is fully transmitted to the wheel rim.

[0037] In this application, the second shifting mechanism 82 is slidably connected to the central shaft 6, and has a first position 820, a second position 821, and a third position 822 on the central shaft 6; when the second shifting mechanism 82 is in the first position 820, the central shaft 6 is engaged with the first central drive gear 801; when the second shifting mechanism 82 is in the second position 821, the central shaft 6 is engaged with the second central drive gear 810; when the second shifting mechanism 82 is in the third position 822, the central shaft 6 is disconnected from the first central drive gear 801 and the second central drive gear 810, so that the first end of the central shaft 6 is connected to the second motor 5, and the second end is set as the second PTO connection end. During gear shifting, the second shifting mechanism 82 slides between the first position 820 and the second position 821 to shift gears. The system triggers the auxiliary power unit, which provides power compensation through the first bias gear mechanism 3 to ensure that there is no power interruption during the shifting process. In the light-load PTO working condition when the tractor is stopped, the third position 822 activates the second motor 5 to independently drive the PTO output, avoiding inefficient PTO power output from the engine 1.

[0038] Example 2 Reference Figure 1-2 A tractor comprising the uninterrupted series hybrid powertrain disclosed in the embodiments.

[0039] The engine 1 outputs power via the first input shaft 10. The first motor 2 is coupled to the first bias gear mechanism 3 via the second input shaft 20. The first shifting mechanism 4 is loosely fitted onto the first input shaft 10 and connected to the first driven bias gear 31, allowing dynamic adjustment of the engagement and disengagement states of the first driven bias gear 31 with the first input shaft 10 or the first driving gear 800. When the first shifting mechanism 4 engages the first driven bias gear 31 with the first driving gear 800, a compensation path for the first motor 2 is formed. When the main drive unit needs to shift gears, the first shifting mechanism 4 immediately engages the first driven bias gear 31 with the first driving gear 800 to form a power shift compensation path. The power of the first motor 2 is continuously transmitted to the output shaft 7 through this path, ensuring that the wheel-side traction force remains stable. In the main drive unit, the second motor 5 is connected to the third input shaft 50, and the second bias gear mechanism 60 directly transmits the motor power to the intermediate shaft 6. The intermediate shaft gear shifting mechanism 8 has a three-position design through the second shifting mechanism 82: first position 820: the intermediate shaft 6 is engaged with the first intermediate drive gear 801; second position 821: the intermediate shaft 6 is engaged with the second drive gear 810; third position 822: the intermediate shaft 6 is disconnected from all gears. During PTO operation while the tractor is in motion, the first shift mechanism 4 engages the first driven bias gear 31 with the first input shaft 10, prioritizing the output of most of the engine 1's power to the PTO. The remaining power is used to drive the first motor 2 to generate electricity and replenish energy via the first bias gear mechanism 3. The electricity is prioritized for charging or directly supplied to the second motor 5 for wheel-side traction. During light-load PTO operation while the tractor is stationary, the first shift mechanism 4 engages the first driven bias gear 31 with the first input shaft 10, connecting the first motor 2 and the engine 1 in series for efficient power generation. The second motor 5 is disengaged and independently drives the PTO, avoiding inefficient output from the engine 1. When the battery is fully charged, the engine 1 stops, and the second motor 5 independently provides pure electric drive to the wheels. In special situations requiring getting out of trouble, the first motor 2 engages to provide assistance.

[0040] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0041] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0042] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. An unpowered interruptible series hybrid powertrain system, characterized by, It comprises: an auxiliary power unit comprising: - an engine (1) connected with a first input shaft (10); - a first electric motor (2) connected with a second input shaft (20); - a first offset gear mechanism (3) arranged between the first input shaft (10) and the second input shaft (20); - a first gear shift mechanism (4) which is loose on the first input shaft (10); a main drive power unit comprising: - a second electric motor (5) connected with a third input shaft (50); - a transfer shaft (6) connected with the third input shaft (50) with a second offset gear mechanism (60); - an output shaft (7); - a transfer shaft gear shift mechanism (8) comprising a first transfer gear pair (80), a second transfer gear pair (81) and a second gear shift mechanism (82), the first transfer gear pair (80) is loose on the first input shaft (10) and the transfer shaft (6) at both ends, and the first transfer gear pair (80) is fixedly connected with the output shaft (7), the second transfer gear pair (81) is fixedly connected with the output shaft (7) at one end and loose on the transfer shaft (6) at the other end, and the second gear shift mechanism (82) is used to adjust the engagement of the transfer shaft (6) with the first transfer gear pair (80) or with the second transfer gear pair (81), and the first gear shift mechanism (4) is used to adjust the engagement of the first offset gear mechanism (3) with the first input shaft (10) or with the first transfer gear pair (80).

2. A passive interrupt series hybrid powertrain system as described in claim 1, wherein: The first offset gear mechanism (3) comprises a first driving offset gear (30) and a first driven offset gear (31) which are meshed with each other, and the first driving offset gear (30) is fixedly connected on the second input shaft (20), and the first driven offset gear (31) is loose on the first input shaft (10).

3. A passive interrupt series hybrid powertrain system as in claim 1, wherein: The second offset gear mechanism (60) comprises a second driving offset gear (600) and a second driven offset gear (601) which are meshed with each other, the second driving offset gear (600) is fixedly sleeved on the third input shaft (50), and the second driven offset gear (601) is fixedly sleeved on the transfer shaft (6).

4. A passive interrupt series hybrid powertrain system as in claim 2, wherein: The first gear shift mechanism (4) is loose on the first input shaft (10) to adjust the engagement of the first driven offset gear (31) with the first input shaft (10) or with the first transfer gear pair (80).

5. An unpowered interrupt series hybrid powertrain system as claimed in claim 4, characterised in that: The first transfer gear pair (80) comprises: a first driving gear (800) which is loose on the first input shaft (10); a first transfer driving gear (801) which is loose on the transfer shaft (6); a first output gear (802) which is fixedly sleeved on the output shaft (7) and simultaneously meshed with the first driving gear (800) and the first transfer driving gear (801), and the first gear shift mechanism (4) is used for the engagement of the first driven offset gear (31) with the first input shaft (10) or with the first driving gear (800).

6. An unpowered interrupt series hybrid powertrain system as claimed in claim 5, characterised in that: The first shift mechanism (4) is connected with the first driven offset gear (31) in the first input shaft (10).

7. A passive interrupt series hybrid powertrain system as in claim 5, wherein: The first input shaft (10) is sleeved with a hollow shaft (100), the first shift mechanism (4) is arranged on the hollow shaft (100), and the hollow shaft (100) is connected with the first driven offset gear (31), and the first driving gear (800) is sleeved on the hollow shaft (100).

8. An unpowered interrupt series hybrid powertrain system as in claim 5, wherein: The second intermediate gear pair (81) comprises: A second intermediate driving gear (810) is sleeved on the intermediate shaft (6); A second output gear (811) is fixedly sleeved on the output shaft (7) and engaged with the second intermediate driving gear (810), and the second shift mechanism (82) is used for adjusting the engagement of the intermediate shaft (6) with the first intermediate driving gear (801) or with the second intermediate driving gear (810).

9. A passive interrupt series hybrid powertrain system as in claim 8, wherein: The second shift mechanism (82) is slidably connected on the intermediate shaft (6) and located between the first intermediate driving gear (801) and the second intermediate driving gear (810).

10. A tractor characterised in that, The tractor comprises the power interruption-free series hybrid power transmission system according to any one of claims 1 to 9. The tractor comprises the power interruption-free series hybrid power transmission system according to any one of claims 1 to 9.

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