Hybrid power system for heavy vehicle

Abstract

A hybrid power system for a heavy vehicle, said system comprising an engine (1), motors (2), a planetary gear mechanism (3), first and second clutches (C1, C2) and a gear case (4); the planetary gear mechanism (3) at least comprises three shafts, the central axes of all the shafts overlapping; the gear case (4) is provided with first and second input shafts (41, 42), a gear case output shaft (43) and at least one intermediate shaft (44); an engine output shaft is connected to one of the shafts of the planetary gear mechanism (3); the second input shaft (42) is connected to another shaft of the planetary gear mechanism (3) by means of the second clutch (C2); a third shaft of the planetary gear mechanism (3) is connected to the first input shaft (41) and is capable of rotating simultaneously with same; motor shafts are connected to the second input shaft (42); the first clutch (C1) is arranged between any two shafts of the planetary gear mechanism (3); each of the first input shaft (41) and the second input shaft (42) is equipped with a synchronizer and is sleeved with a driving gear; a plurality of driven gears are fixedly connected onto the intermediate shaft (44). During startup of the vehicle, the engine (1) and the motors (2) differentially drive the vehicle by means of the planetary gear mechanism (3).

Description

A hybrid power system suitable for heavy vehicles Technical Field

[0001] The present invention relates to the technical field of hybrid vehicle manufacturing, in particular to a hybrid power system suitable for heavy vehicles. Background Art

[0002] With the implementation of the dual carbon strategy, upgrading traditional internal combustion engine heavy-duty vehicles to hybrid power is imperative. Hybrid power can effectively meet the carbon emission and fuel consumption requirements of heavy-duty trucks, and has a broad market potential. A key component of hybrid vehicles is the hybrid transmission.

[0003] Heavy-duty vehicles are heavy, typically weighing over 15 tons, and some can reach over 100 tons. They require high torque for acceleration and climbing. Transmission input torque can exceed 2,000 Nm, output torque can exceed 30,000 Nm, and wheel torque can reach 100,000 to 200,000 Nm. This requires a transmission capable of transmitting high torque and a wide reduction-torque-to-speed ratio. They must be able to reach speeds of around 100 km / h, and high-speed driving requires high wheel speeds, necessitating a small reduction ratio. This necessitates a large ratio differential (the ratio of the maximum to minimum speed ratio), typically exceeding 15. By comparison, passenger car transmissions typically have input torques of 100 to 400 Nm, wheel torques of 2,000 to 3,000 Nm, and a ratio differential generally no greater than 10. Due to these significant differences in requirements, the hybrid transmissions required for heavy-duty vehicles differ significantly from the hybrid technology widely used in passenger cars.

[0004] In many cases, the hybrid transmission system used in heavy-duty vehicles is an improved hybrid transmission system based on the transmission. This is an add-on hybrid transmission system, which adds a motor to the transmission input and a clutch between the motor and the engine. This is commonly known as a P2 hybrid transmission. The transmission can be an automatic manual transmission, an automatic transmission, or a dual-clutch transmission.

[0005] US patent application US2014 / 0144288 discloses a P2+AMT hybrid system. The system consists of an electric motor (EM), transmission bodies 8 and 10, and a sub-transmission 12. The transmission bodies 8 and 10 have six forward gears, while the sub-transmission 12 comprises a two-speed transmission mechanism consisting of a planetary gearbox and synchronizers, for a total of 6 x 2 = 12 gears. This hybrid transmission has many advantages: it delivers high torque, meeting power requirements, enabling high-speed driving, and significantly reducing fuel consumption. Its simple structure, consisting of simply adding a motor to the AMT transmission, results in low manufacturing and operating costs. Its synchronizer-operated, parallel-shaft gear drive system delivers high torque and efficiency. It shares most components with widely used manual transmissions (MTs) and automatic manual transmissions (AMTs), boasts mature technology, and a comprehensive supply chain. It can be manufactured on the same production lines as MT or AMT transmissions, requiring minimal initial investment in plant and equipment. However, this transmission mechanism also has some weaknesses: when a heavy-loaded vehicle starts, the system needs to rely on the clutch friction plate to transmit the torque output by the engine, which is easy to burn the friction plate and cannot output all the torque, which can easily lead to problems such as difficulty in climbing a slope with a heavy load and difficulty in getting out of trouble; due to the heavy load of heavy-loaded vehicles, the speed ratio of the gearbox is large, so the sub-transmission needs to be adjusted to high / low speed, and due to the large torque value that needs to be transmitted at the sub-transmission, the gear shifting mechanism is expensive and makes the gear shifting mechanism prone to failure; when shifting gears, the clutch must be disengaged, the original gear must be disengaged, the new gear must be engaged, and the clutch must be closed, which inevitably interrupts power. When a heavy-loaded vehicle climbs a slope, it may slip, posing a safety hazard.

[0006] U.S. Patent No. 10,576,814 discloses a hybrid powertrain system comprising an engine 4, a first motor 14, a second motor 16, a first planetary gear set 10, a second planetary gear set 12, a transmission 19, and an auxiliary transmission 11. The transmission 19 has two input shafts 34 and 36. This system features high starting torque, strong heavy-load hill-climbing and escape capabilities, and no clutch slippage is required to transmit torque. During gear shifts, one motor maintains drive while the other drags the engine, achieving power-free shifting. The transmission 19 has several gear positions, and the auxiliary transmission 11 has two gear positions, widening the speed ratio range. A dual-input auxiliary transmission is employed, enabling full power-free shifting. However, this system, with two motors, two planetary gear sets, and a relatively complex auxiliary transmission structure and control, results in a complex construction and high cost.

[0007] CN115008997A discloses a "dual-motor, multi-speed parallel hybrid system for heavy-duty trucks." The system includes a housing, a generator, a drive motor, an engine, an axle, and a dual planetary gear set. The rear ring gear is connected to the axle and to the front planetary carrier. The engine is connected to the rear planetary carrier via a central shaft. The rear sun gear is connected to an inner hollow shaft connected to the generator, and the front sun gear is connected to an outer hollow shaft connected to the drive motor. A sliding sleeve locking device is mounted on the housing. The generator regulates the speed of the rear sun gear to achieve continuously variable transmission, improving vehicle comfort. Engine speed is decoupled from vehicle speed, allowing for continuous operation within the economic range and enhancing vehicle economy. Torque compensation between the generator and engine ensures uninterrupted power during shifting, improving vehicle safety. This improves vehicle power while meeting requirements for uninterrupted power during shifting, continuously variable transmission, and decoupling of engine speed and vehicle speed. However, this structure has two motors and two planetary gear sets. Compared to the P2 parallel hybrid system, which is predominant in the heavy-duty truck industry, the addition of one motor and two planetary gear sets significantly increases costs.

[0008] CN115773341A discloses a "Continuously Variable Transmission with Uninterrupted Power." The transmission comprises a transmission body with a first shifting device, a second shifting device, a third shifting device, and a fourth shifting device arranged sequentially from the input end to the output end of a central shaft. The second shifting device is disposed between the tenth and eleventh transmission gears of the first hollow shaft, the third shifting device is disposed between the fifth and sixth transmission gears of the second hollow shaft, and the fourth shifting device is disposed at the left end of the front planetary carrier. The rear planetary carrier is connected to the second hollow shaft and the central shaft via bearings and splines, respectively, and the front planetary carrier is connected to the second hollow shaft via bearings. This invention reduces shifting frequency, ensures uninterrupted output power during vehicle shifting, and provides continuously variable transmission with no shifting jerk, thereby improving vehicle comfort, economy, and safety. Compared with the traditional P2 parallel hybrid system, its system adds an electric motor, a planetary gear mechanism, and a more complex shaft system, which solves problems such as power interruption during gear shifting, difficulty in climbing, and clutch slip loss during starting conditions, but its system cost is also greatly increased.

[0009] U.S. Patent No. 7,082,850B2 discloses a hybrid system that utilizes a P2+DCT transmission (i.e., adding an electric motor to the input of a DCT dual-clutch transmission, with a clutch between the motor and the engine). This design allows for shifting without power interruption, improving vehicle safety. However, for heavy-duty vehicles, the DCT also requires a sub-transmission, making complete shifting without power interruption impossible. Furthermore, the DCT dual-clutch module is extremely expensive, and its application in heavy-duty vehicles is technically challenging. Currently, no heavy-duty trucks equipped with the P2+DCT hybrid transmission have been mass-produced.

[0010] U.S. Patent US9108635B2 discloses a hybrid system utilizing a P2+AT transmission (an electric motor is added to the AT transmission input, with a clutch between the motor and the engine). Due to the AT transmission's powerful torque converter, its heavy-load hill-start and escape capabilities are significantly superior to the clutches of AMT and DCT. Furthermore, AT transmissions are capable of shifting without power interruption. However, high-torque AT transmissions are expensive, and there is a lack of high-torque AT transmissions on the market, especially in China. Research and development costs, such as retooling, are prohibitive. Therefore, the development of a P2+AT transmission hybrid transmission system for heavy-duty vehicles lacks the fundamental technical foundation and presents a poor cost-effectiveness ratio. Summary of the Invention

[0011] The technical problem to be solved by the present invention is to provide a hybrid power system suitable for heavy vehicles, which has a high cost-effectiveness when applied to heavy vehicles, facilitates the starting and escape of heavy vehicles, can realize gear shifting without power interruption, and has good driving smoothness.

[0012] To achieve the above-mentioned object, the technical solution of the present invention is as follows: a hybrid power system suitable for heavy vehicles, comprising an engine, a motor, a planetary gear mechanism, a first clutch, a second clutch, and a gearbox, wherein the planetary gear mechanism comprises at least three shafts, and the central axes of all the shafts of the planetary gear mechanism overlap;

[0013] The gearbox is provided with a first input shaft, a second input shaft, a gearbox output shaft, and at least one intermediate shaft. The central axes of the first input shaft and the second input shaft overlap, and the intermediate shaft is parallel to the first input shaft. The engine output shaft is connected to one shaft of the planetary gear mechanism. The second input shaft is connected to another shaft of the planetary gear mechanism via a second clutch. Another shaft of the planetary gear mechanism is connected to the first input shaft and can rotate simultaneously. The motor shaft is connected to the second input shaft.

[0014] The first clutch is provided between any two shafts of the planetary gear mechanism;

[0015] The first input shaft and the second input shaft are both equipped with synchronizers and are sleeved with driving gears, the intermediate shaft is fixedly connected to a plurality of driven gears, the gearbox is also equipped with at least one reverse gear, and the output shaft of the gearbox is fixedly connected to an output gear;

[0016] The reverse gear is meshed with a driven gear on the intermediate shaft and a driving gear on the first input shaft at the same time, the output gear is meshed with one of the driven gears on the intermediate shaft, and except for one driving gear on the first input shaft which is meshed with the reverse gear, each of the other driving gears is meshed with a driven gear on the intermediate shaft, and the remaining driven gears on the intermediate shaft are respectively meshed with the driving gears on the second input shaft. The gearbox forms neutral, reverse and multiple forward gears in conjunction with the position switching of the multiple synchronizers.

[0017] When a heavy vehicle starts, the first clutch is disengaged, the second clutch is locked, and the engine and the motor differentially drive the vehicle through the planetary gear mechanism.

[0018] Preferably, the planetary gear mechanism includes three shafts, namely the ring gear shaft, the sun gear shaft and the planet carrier shaft, and the central axes of the ring gear shaft, the sun gear shaft and the planet carrier shaft overlap; the first clutch is arranged between any two of the ring gear shaft, the sun gear shaft and the planet carrier shaft; the central axes of the first input shaft and the second input shaft overlap with the central axis of the planet carrier shaft.

[0019] It is further preferred that the engine output shaft is connected to the ring gear shaft, the second input shaft is connected to the sun gear shaft via a second clutch, the first input shaft is connected to the planetary carrier shaft and can rotate simultaneously, and the first clutch is provided between the sun gear shaft and the ring gear shaft;

[0020] Or the engine output shaft is connected to the planetary carrier shaft, the second input shaft is connected to the sun gear shaft through the second clutch, the ring gear shaft is connected to the first output shaft and can rotate simultaneously, and the first clutch is arranged between the ring gear shaft and the sun gear shaft;

[0021] Or the engine output shaft is connected to the sun gear shaft, the second input shaft is connected to the ring gear shaft through the second clutch, the planetary carrier shaft is connected to the first input shaft and can rotate simultaneously; the first clutch is arranged between the ring gear shaft and the sun gear shaft.

[0022] As a further improvement, the motor shaft is connected to the second input shaft through a reduction assembly. Current heavy-duty vehicles use large-displacement diesel engines with a narrow speed range, generally 1000rpm-2800rpm, while the motors selected in hybrid systems can generally reach around 10,000rpm, with better performance / efficiency at higher speeds; if the motor is directly connected to the engine, the motor cannot operate in a high-efficiency range. The output shaft of the motor of the present invention is connected to the engine through a reduction assembly, which can enable the motor to operate in a high-efficiency range and improve the efficiency of the motor. The present invention is configured as a hybrid system for heavy-duty vehicles with large transmission torque and large motor torque requirements under pure electric conditions. The output shaft of the motor of the present invention is connected to the second input shaft after passing through the reduction assembly, which can amplify the torque and meet the torque requirements of pure electric drive of heavy-duty vehicle models.

[0023] Furthermore, there are two motors, namely a first motor and a second motor; the first motor shaft is connected to the second input shaft through a first reduction assembly, the first reduction assembly includes a first gear fixedly connected to the first motor shaft and a third gear fixedly connected to the second input shaft, and the first gear is meshed with the third gear;

[0024] The second motor shaft is connected to the second input shaft via a second reduction assembly. The second reduction assembly includes a second gear fixedly connected to the second motor shaft and a third gear fixedly connected to the second input shaft. The second gear meshes with the third gear. This reduces the power required by each motor, lowers the overall cost of the motor, and increases flexibility.

[0025] There are two intermediate shafts, each of which is fixedly connected to a plurality of driven gears. This structure is more conducive to power transmission. Preferably, the two intermediate shafts are symmetrically arranged relative to the first input shaft.

[0026] Preferably, the second input shaft is sleeved with two driving gears, namely a first driving gear and a second driving gear. The first driving gear is engaged with a driven gear fixed to the intermediate shaft, and the second driving gear is engaged with another driven gear fixed to the intermediate shaft. The synchronizer on the second input shaft can be engaged with the first driving gear or the second driving gear, or not engaged with the first driving gear and the second driving gear.

[0027] Preferably, three synchronizers are installed on the first input shaft, one of which can be engaged with one of the driving gears on the first input shaft or with the output gear, or not engaged with the driving gear and the output gear on the first input shaft, and the other synchronizers on the first input shaft can be engaged with the driving gears on the first input shafts on both sides thereof or not engaged at all.

[0028] Furthermore, the reverse gear is fixedly connected to a reverse gear shaft, which is pivotally connected to the housing of the gearbox. The reverse gear shaft is parallel to the intermediate shaft and the number of the reverse gear shaft is the same as that of the intermediate shaft.

[0029] As a further improvement, the transmission system also includes a reduction mechanism comprising a reduction mechanism input shaft and a reduction mechanism output shaft, the reduction mechanism input shaft being connected to the gearbox output shaft. Adjusting the speed ratio of the reduction mechanism adjusts the output torque and output speed of the hybrid transmission system to meet the needs of different vehicle models. This also enables modular design and production, reducing corresponding R&D and production costs.

[0030] As a preferred embodiment, the reduction mechanism input shaft is connected to the gear box output shaft as a whole, and the central axes of the reduction mechanism input shaft and the reduction mechanism output shaft are arranged to overlap. The reduction mechanism includes two transmission shafts, the reduction mechanism input shaft is fixedly connected to the fourth gear, and the reduction mechanism output shaft is fixedly connected to the fifth gear. Each transmission shaft is fixedly connected to the sixth gear and the seventh gear, the sixth gear is meshed with the fourth gear, and the seventh gear is meshed with the fifth gear.

[0031] As another preferred embodiment, the reduction mechanism includes a second ring gear, a second sun gear and multiple second planetary gears, each second planetary gear is engaged with the second ring gear and the second sun gear at the same time, multiple second planetary gears are connected to the second planetary carrier, the second planetary carrier is fixedly connected to the reduction mechanism output shaft, the second ring gear is fixedly connected to the reduction mechanism housing, the second sun gear is fixedly connected to the reduction mechanism input shaft, the reduction mechanism input shaft is integrated with the gear box output shaft, and the central axes of the reduction mechanism input shaft and the reduction mechanism output shaft are arranged to overlap.

[0032] The beneficial effects of the present invention are as follows:

[0033] 1. This system's engine and motor are differentially driven via a planetary gear mechanism, replacing the starting clutch. This allows full torque drive to start the vehicle, delivering stable output torque. Under full torque conditions, the vehicle can be switched from the starting state to first gear. During engine shifts, the motor compensates for engine torque and continues driving, maintaining continuous driving force. This facilitates starting and unstuck heavy vehicles, avoiding the difficulties existing heavy vehicles face in climbing heavily loaded grades and unstuck situations. Furthermore, by replacing the traditional starting clutch, this system avoids the existing heavy-duty vehicle's reliance on clutch friction plate slip to transmit torque, which can easily cause friction plate wear and prevent full torque output.

[0034] 2. This system uses a planetary gear mechanism to increase the speed ratio range. Without a sub-transmission, the speed ratio range can reach the 15-20 speed ratio range required for heavy-duty vehicles. The gearbox of a heavy-duty vehicle requires a speed ratio range of more than 15, and most heavy-duty vehicle AMT gearboxes require a sub-transmission to achieve this. The sub-transmission has a large input torque, and the shift mechanism bears a large load. The load and complexity of the shift actuator also increase, and the cost is high. The elimination of the sub-transmission in this system can reduce the load on its gear-engaging components, reduce the technical difficulty of the gear-engaging devices (clutch / synchronizer), improve reliability, achieve full-process power-free shifting, and reduce costs.

[0035] This system uses a planetary gear mechanism to increase the speed ratio range, which can achieve 7+1 (7 actual gear positions of the hybrid box + 1 differential gear position of the planetary gear mechanism), achieving the speed ratio span that can be achieved by the existing technology gearbox 2×4×2 or 6×2. The integration is greatly improved, and the space and weight are effectively reduced.

[0036] 3. This system utilizes the dual input shafts of the transmission, allowing the engine and drive motor to alternately drive and shift gears, achieving shifting without power interruption, thus avoiding problems such as difficult shifting on hills and even rolling. This dual power source allows for smooth operating mode switching. The engine is one power source, and the motor is the other. When a gear shift is required, the motor first drives the vehicle through the existing gear, while the engine switches to the new gear; then, the engine drives the vehicle through the new gear, completing the gear shift. Alternatively, the engine first drives the vehicle through the existing gear, while the motor switches to the new gear; then, the motor drives the vehicle through the new gear, while the engine switches to the new gear, completing the gear shift. This allows shifting without power interruption, resulting in a smoother ride.

[0037] 4. This system can add derivative gears, improving engine fuel consumption; it can also achieve partial continuous speed shifting, reducing fuel consumption on urban roads. In terms of application scenarios, this system is well-suited for medium- and heavy-duty commercial vehicles, enhancing the vehicle's ability to escape from difficulties. Using a differential mode, heavy-duty trucks can output maximum torque at zero speed, significantly enhancing their ability to start uphill and escape difficulties. Shifting without power interruption can prevent the vehicle from sliding backward when shifting power is interrupted while climbing steep slopes. The horizontal block design can accommodate a wider range of engines and meet the needs of a wider range of vehicle models.

[0038] 5. Compared to a "P2+AMT" hybrid system, this system boasts comparable costs, yet completely overcomes the AMT's biggest shortcoming—power interruption during shifting. This design concept abandons the traditional "add-on" approach. The motor isn't simply attached to the transmission; instead, the motor and transmission are integrated, leveraging the added motor's unique characteristics. The entire hybrid system is considered a dual-power system (engine and motor). By leveraging the dual-channel nature of the dual-input shaft gearbox, the engine and motor alternately drive and shift gears, eliminating the need for two clutches to achieve power shifting, thus reducing technical complexity. Furthermore, the system reduces synchronizer engagement time requirements, simplifying the gear engagement mechanism and reducing costs. This effectively resolves the issue of smooth shifting.

[0039] 6. Compared to a P2+AT or P2+DCT system, this system offers equal or even superior driving comfort, but at a significant cost advantage and a high cost-performance ratio. Through its modular design, the hybrid system can meet the powertrain requirements of a wider range of heavy-duty vehicle models.

[0040] 7. This system expands the total step difference of the hybrid transmission, omits the auxiliary transmission, has greater cost advantages, and the overall structural layout is more flexible. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] FIG1 is a schematic diagram of a first embodiment of the present invention;

[0042] FIG2 is a schematic diagram of a second embodiment of the present invention;

[0043] FIG3 is a schematic diagram of a third embodiment of the present invention;

[0044] FIG4 is a schematic diagram of a fourth embodiment of the present invention;

[0045] FIG5 is a schematic diagram of a fifth embodiment of the present invention. DETAILED DESCRIPTION

[0046] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0047] Embodiment 1, as shown in Figure 1, a hybrid power system suitable for heavy vehicles includes an engine 1, a motor 2, a planetary gear mechanism 3, a first clutch C1, a second clutch C2 and a gearbox 4. The planetary gear mechanism 3 includes three shafts, namely a ring gear shaft 32, a sun gear shaft 34 and a planet carrier shaft 37. The planetary gear mechanism 3 also includes a ring gear 31, a sun gear 33 and three planetary gears 35. The ring gear shaft 32 is fixedly connected to the ring gear 31, and the ring gear 31 can be integrated with the ring gear shaft 32. The sun gear shaft 34 is fixedly connected to the sun gear 33, and the sun gear 33 can be integrated with the sun gear shaft 34. The three planetary gears 35 are connected to the planet carrier 36, and the planet carrier 36 is fixedly connected to the planet carrier shaft 37, and the planet carrier 36 can be integrated with the planet carrier shaft 37. The central axes of the ring gear shaft 32, the sun gear shaft 34 and the planet carrier shaft 37 are arranged to overlap. The sun gear shaft 34 is a hollow shaft, and the sun gear shaft 34 is sleeved on the planet carrier shaft 37.

[0048] Planetary gear mechanisms can take many forms and include at least three shafts: a sun gear shaft, a planet carrier shaft, and a ring gear shaft; a first sun gear shaft, a planet carrier shaft, and a second sun gear shaft; or a first ring gear shaft, a planet carrier shaft, and a second ring gear shaft. These various planetary gear mechanisms have similar characteristics and functions and can be substituted for one another. This embodiment uses a planetary gear mechanism 3 comprising a ring gear shaft 31, a sun gear shaft 33, and a planet carrier shaft 37 as an example to illustrate the operating principles of this system; the operating principles of this system are also applicable to other planetary gear mechanisms.

[0049] The gearbox 4 is provided with a first input shaft 41, a second input shaft 42, a gearbox output shaft 43 and two intermediate shafts 44. The first input shaft 41, the second input shaft 42, the gearbox output shaft 43 and the two intermediate shafts 44 are all rotatably connected to the housing of the gearbox 4. The central axes of the first input shaft 41 and the second input shaft 42 are arranged to overlap. In this embodiment, the central axes of the first input shaft 41 and the second input shaft 42 are also arranged to overlap with the central axis of the planetary carrier shaft 37. The second input shaft 42 is a hollow shaft. The second input shaft 42 is sleeved on the first input shaft 41. The intermediate shaft 44 and the first input shaft 41 are parallel to each other. The first input shaft 41 is connected to the planetary carrier shaft 37 and can rotate simultaneously. The output shaft of the engine 1 is connected to the ring gear shaft 32, and the output shaft of the engine 1 can also be connected to the ring gear shaft 32 as a whole.

[0050] The motor 2 is connected to the second input shaft 42. Usually, the maximum speed of the motor is much higher than the speed of the engine output shaft, and the size, weight and cost of the motor are linearly related to the torque. In this embodiment, it is preferred to connect a set of reduction gears between the motor 2 and the second input shaft 42 to increase the output torque of the motor 2 to reduce the speed of the second input shaft 42. Furthermore, the cost of small motors widely used in existing automobiles is much lower than that of large motors. Replacing a large motor with two smaller motors has cost advantages and flexible layout. Therefore, in this embodiment, it is preferred that there are two motors 2, namely the first motor 21 and the second motor 22; the rotating shaft of the first motor 21 is connected to the second input shaft 42 through the first reduction assembly 2a, and the first reduction assembly 2a includes a first gear Ga fixedly connected to the rotating shaft of the first motor 21 and a third gear Gc fixedly connected to the second input shaft 42, and the first gear Ga is meshed with the third gear Gc;

[0051] The rotating shaft of the second motor 22 is connected to the second input shaft 42 through the second reduction assembly 2b. The second reduction assembly 2b includes a second gear Gb fixedly connected to the rotating shaft of the second motor 22 and a third gear Gc fixedly connected to the second input shaft 42. The second gear Gb is meshed with the third gear Gc.

[0052] The first clutch C1 can be provided between any two of the three shafts of the planetary gear mechanism. In this embodiment, the first clutch C1 is preferably provided between the ring gear shaft 32 and the sun gear shaft 34 , and the second clutch C2 is provided between the second input shaft 42 and the sun gear shaft 34 .

[0053] The second input shaft 42 is provided with a first synchronizer S1 and is sleeved with a first driving gear Gd and a second driving gear Ge. The first synchronizer S1 can be engaged with the first driving gear Gd or the second driving gear Ge, or not engaged with either the first driving gear Gd or the second driving gear Ge.

[0054] The first input shaft 41 is equipped with three synchronizers, namely the second synchronizer S2, the third synchronizer S3, and the fourth synchronizer S4; the first input shaft 41 is also covered with five driving gears, namely the third driving gear Gf, the fourth driving gear Gg, the fifth driving gear Gh, the sixth driving gear Gi, and the seventh driving gear Gj. The two intermediate shafts 44 are fixedly connected with the first driven gear G1, the second driven gear G2, the third driven gear G3, the fourth driven gear G4, the fifth driven gear G5, the sixth driven gear G6, the seventh driven gear G7, and the eighth driven gear GR. The gearbox output shaft 4 3 is fixedly connected to the output gear Gm; the fourth synchronizer S4 can be engaged with the seventh driving gear Gj or the output gear Gm, or not engaged with both the seventh driving gear Gj and the output gear Gm; the second synchronizer S2 can be engaged with the third driving gear Gf on both sides thereof, or with the fourth driving gear Gg, or not engaged with both the third driving gear Gf and the fourth driving gear Gg; the third synchronizer S3 can be engaged with the fifth driving gear Gh on both sides thereof, or with the sixth driving gear Gi, or not engaged with both the fifth driving gear Gh and the sixth driving gear Gi.

[0055] The gearbox 4 is equipped with two reverse gears Gk, each reverse gear Gk is fixedly connected to a reverse gear shaft 45, and the reverse gear Gk and the reverse gear shaft 45 can also be connected as one. Each reverse gear shaft 45 is pivotally connected to the gearbox 4 housing, and the reverse gear shaft 45 is parallel to the intermediate shaft 44.

[0056] It can be further seen from Figure 1 that each reverse gear Gk is simultaneously engaged with the eighth driven gear GR and the fourth driving gear Gg, the output gear Gm is simultaneously engaged with the two seventh driven gears G7, the first driving gear Gd is simultaneously engaged with the two second driven gears G2, the second driving gear Ge is simultaneously engaged with the two fifth driven gears G5, the third driving gear Gf is simultaneously engaged with the two fourth driven gears G4, the fifth driving gear Gh is simultaneously engaged with the two first driven gears G1, the sixth driving gear Gi is simultaneously engaged with the two third driven gears G3, and the seventh driving gear Gj is simultaneously engaged with the two sixth driven gears G6. Combined with the position switching of multiple synchronizers, the gearbox 4 forms a neutral gear, a reverse gear and multiple forward gears.

[0057] The two intermediate shafts 44 are symmetrically arranged relative to the first input shaft 41 , and the two reverse gear shafts 45 are also symmetrically arranged relative to the first input shaft 41 .

[0058] This embodiment can achieve the following working conditions:

[0059] 1. The first clutch C1 is disengaged, the second clutch C2 is locked, and the engine 1 is connected to the first motor 21 and the second motor 22 via the planetary gear mechanism 3; idle start-stop and idle power generation can be achieved.

[0060] In this state, the first synchronizer S1 of the gear box 4 is in the middle position and in neutral, and the third synchronizer S3 can be shifted to the left and combined with the fifth driving gear Gh to engage in first gear.

[0061] 2. The first clutch C1 is disengaged, the second clutch C2 is disengaged, and the engine 1 is separated from the first motor 21 and the second motor 22; the gearbox 4 shifts the second input shaft 42 into upper gear, that is, the first synchronizer S1 engages with the first driving gear Gd or the second driving gear Ge, achieving pure electric EV operation.

[0062] 3. The first clutch C1 is disengaged and the second clutch C2 is locked. The first motor 21 and the second motor 22 are connected to the sun gear shaft 34 and the sun gear 33 via the second clutch C2. Only a gear on the first input shaft 41 is engaged, that is, one of the synchronizers on the first input shaft 41 is engaged with a driving gear on the first input shaft 41 or directly engaged with the output gear Gm. The engine 1 and the first motor 21 and the second motor 22 are differentially driven.

[0063] 4. The first clutch C1 is locked, the second clutch C2 is disengaged, the engine 1 is connected to the first input shaft 41 through the planetary gear mechanism 3, and the engine 1 is separated from the first motor 21 and the second motor 22; the gears on the first input shaft 41 and the second input shaft 42 are respectively engaged, and the engine 1 and the first motor 21 and the second motor 22 can realize split-shaft drive, that is, the engine 1 can drive the vehicle through the first input shaft 41, and the motor can drive the vehicle through the second input shaft 42 at the same time.

[0064] 5. The first clutch C1 is locked, the second clutch C2 is locked, and the engine 1 is locked with the first and second motors 21, 22, the first input shaft 41, and the second input shaft 42. A gear is engaged on the first input shaft 41, and the engine 1 and the first and second motors 21, 22 coaxially drive the first input shaft 41. A gear is engaged on the second input shaft 42, and the engine 1 and the first and second motors 21, 22 coaxially drive the second input shaft 42.

[0065] The various working conditions of this embodiment are further described as follows:

[0066] 1. Idle start-stop:

[0067] The engine 1 has an idle start-stop function.

[0068] 2. Idle power generation:

[0069] With engine 1 running, first clutch C1 disengaged, and second clutch C2 locked, engine 1 is connected to first motor 21 and second motor 22 via planetary gear mechanism 3. First synchronizer S1 of gearbox 4 is in neutral, shifting to the left and engaging fifth drive gear Gh to shift into first gear. This allows engine 1 to drive first motor 21 and second motor 22 to generate electricity, charging the drive battery and powering the electric air conditioner.

[0070] 3. Pure electric drive condition (EV):

[0071] The second clutch C2 is disengaged, the first synchronizer S1 is engaged with the first driving gear Gd on the left side or with the second driving gear Ge on the right side, and then engaged with the output gear Gm through the seventh driven gear G7, and the first motor 21 and the second motor 22 can output power; the first motor 21 and the second motor 22 can also reversely drive the vehicle to reverse; or the first motor 21 and the second motor 22 can also achieve energy regenerative braking, and the first motor 21 and the second motor 22 only need to output torque in the opposite direction of rotation.

[0072] 4. Hybrid drive mode (HEV):

[0073] Engine 1 is running, and the gear settings are as follows:

[0074] 1) Hybrid coaxial drive operating condition (hybrid coaxial drive first input shaft 41 and hybrid coaxial drive second input shaft 42):

[0075] Hybrid coaxial drive first input shaft 41:

[0076] First gear: the first clutch C1 is locked, the second clutch C2 is locked, the third synchronizer S3 is engaged with the fifth driving gear Gh on the left, and then through the first driven gear G1, the seventh driven gear G7 and the output gear Gm, the engine 1 connects the first input shaft 41 with the corresponding gear set through the first clutch C1 and the planetary gear mechanism 3 to drive the vehicle forward, and the first motor 21 and the second motor 22 connect the first input shaft 41 with the corresponding gear set through the second clutch C2 and the planetary gear mechanism 3 to drive the vehicle forward.

[0077] Third, fourth, sixth and seventh gears: Similar to the first gear mentioned above, the clutch C1 and the second clutch C2 have the same opening and closing conditions, and the corresponding gear is engaged by the corresponding synchronizer. The engine 1 connects the first input shaft 41 and the corresponding gear set through the first clutch C1 and the planetary gear mechanism 3 to drive the vehicle forward, and the first motor 21 and the second motor 22 connect the first input shaft 41 and the corresponding gear set through the second clutch C2 and the planetary gear mechanism 3 to drive the vehicle forward.

[0078] Hybrid coaxial drive second input shaft 42:

[0079] Second gear: the first clutch C1 is locked, the second clutch C2 is locked, the first synchronizer S1 is engaged with the left side and the first driving gear Gd, and then through the second driven gear G2, the seventh driven gear G7 and the output gear Gm, the engine 1 is connected to the second input shaft 42 and the corresponding gear set through the first clutch C1, the second clutch C2, and the planetary gear mechanism 3 to drive the vehicle forward, and the first motor 21 and the second motor 22 are connected to the second input shaft 42 and the corresponding gear set to drive the vehicle forward.

[0080] Fifth gear: The first clutch C1 is locked, the second clutch C2 is locked, the first synchronizer S1 is engaged to the right with the second driving gear Ge, and then through the fifth driven gear G5, the seventh driven gear G7 and the output gear Gm, the engine 1 is connected to the second input shaft 42 and the corresponding gear set through the first clutch C1, the second clutch C2, and the planetary gear mechanism 3 to drive the vehicle forward, and the first motor 21 and the second motor 22 are connected to the second input shaft 42 and the corresponding gear set to drive the vehicle forward.

[0081] 2) Hybrid split shaft drives the first input shaft 41 and the second input shaft 42:

[0082] Low speed conditions:

[0083] 1. The split shaft drives the second gear and the first gear: the first clutch C1 is locked, the second clutch C2 is disengaged, the split shaft drives the first gear, the third synchronizer S3 is engaged to the left with the fifth driving gear Gh, and the engine 1 drives the vehicle forward through the first clutch C1, the planetary gear mechanism 3, the first input shaft 41 and the gear set corresponding to the first gear; the split shaft drives the second gear, the first synchronizer S1 is engaged to the left with the first driving gear Gd, and the first motor 21 and the second motor 22 drive the vehicle forward through the second input shaft 42, the first synchronizer S1 and the gear set corresponding to the second gear.

[0084] 2. Split-shaft drive second and third gears: Similar to the two low-speed operating conditions mentioned above, the clutch opening and closing conditions are the same, and the corresponding synchronizer is used to shift to the corresponding gear position. The engine 1 and the first motor 21 and the second motor 22 drive the vehicle forward through the corresponding mechanisms.

[0085] High-speed working conditions:

[0086] 3. Split-shaft drive fifth and fourth gears: The first clutch C1 is locked, the second clutch C2 is disengaged, the split-shaft drives fifth gear, the first synchronizer S1 is engaged to the right with the second driving gear Ge, and the first motor 21 and the second motor 22 drive the vehicle forward through the second input shaft 42, the first synchronizer S1 and the corresponding gear set of the fifth gear;

[0087] The split shaft drives the fourth gear, the second synchronizer S2 is engaged with the third driving gear Gf on the left, and the engine 1 drives the vehicle forward through the first clutch C1, the planetary gear mechanism 3, the first input shaft 41 and the gear set corresponding to the fourth gear.

[0088] 4. Split-shaft drive fifth and sixth gears: The first clutch C1 is locked, the second clutch C2 is disengaged, the split-shaft drives fifth gear, the first synchronizer S1 is engaged to the right with the second driving gear Ge, and the first motor 21 and the second motor 22 drive the vehicle forward through the second input shaft 42, the first synchronizer S1 and the corresponding gear set of fifth gear;

[0089] The split shaft drives the sixth gear, the fourth synchronizer S4 is engaged with the seventh driving gear Gj on the left, and the engine 1 drives the vehicle forward through the first clutch C1, the planetary gear mechanism 3, the first input shaft 41 and the gear set corresponding to the sixth gear.

[0090] 5. Split-shaft drive fifth and seventh gears: The first clutch C1 is locked, the second clutch C2 is disengaged, the split-shaft drives fifth gear, the first synchronizer S1 is engaged to the right with the second driving gear Ge, and the first motor 21 and the second motor 22 drive the vehicle forward through the second input shaft 42, the first synchronizer S1 and the corresponding gear set of the fifth gear;

[0091] The split shaft drives the seventh gear, the fourth synchronizer S4 is engaged with the output gear Gm on the right, and the engine 1 drives the vehicle forward through the first clutch C1, the planetary gear mechanism 3, and the first input shaft 41.

[0092] 3) Differential drive:

[0093] Overall setting: the first clutch C1 is disengaged, the second clutch C2 is locked, and the first input shaft 41 is engaged in gear.

[0094] Working condition 1, stopping and starting the engine 1: the first synchronizer S1, the second synchronizer S2, the third synchronizer S3, and the fourth synchronizer S4 are all in the middle position and in neutral, the first motor 21 and the second motor 22 are reversed, dragging the engine 1 to rotate forward and start.

[0095] Working condition 2, parking and power generation: engage P gear (or step on the brake) and the first input shaft 41 in first gear (the third synchronizer S3 is engaged on the left side with the fifth driving gear Gh in first gear, and the first synchronizer S1 is in the middle position and in neutral), the engine 1 rotates forward to output power, and the first motor 21 and the second motor 22 rotate reversely to absorb power and generate electricity.

[0096] Working condition 3, engine 1 drives the vehicle to start: the first input shaft 41 is engaged, the brake pedal is released, the engine 1 increases the torque, increases the torque and accelerates in the positive direction, and drives the vehicle to accelerate through the first input shaft 41; at the same time, the first motor 21 and the second motor 22 increase the torque and accelerate in the positive direction, and drive the vehicle to accelerate through the second clutch C2, the planetary gear mechanism 3, and the first input shaft 41.

[0097] Differential Drive: The first clutch C1 is disengaged and the second clutch C2 is locked. Engine 1 power is transmitted via the engine's output shaft to the ring gear 31 of the planetary gear mechanism 3. The first and second motors 21 and 22 are then transmitted to the sun gear 33 via the second clutch C2. The planetary carrier 36 drives the wheels via the first input shaft 41 and the corresponding gear set. When the vehicle is stationary, the planetary carrier 36 is fixed. The engine 1 transmits power to the first and second motors 21 and 22 via the planetary gear mechanism 3, driving them to rotate and generate electricity. To start the vehicle, controlling the speed of the first and second motors 21 and 22 controls the speed of the planetary carrier 36, thereby transferring engine 1 power to the gearbox 4 to drive the vehicle. The planetary gear mechanism 3 then increases the engine's output torque according to the speed ratio. When the speeds of the first and second motors 21 and 22 approach those of the engine 1, the first clutch C1 is locked and the second clutch C2 is disengaged. At this point, the planetary gear mechanism 3 is locked, and the engine's power directly drives the vehicle.

[0098] In this embodiment, when starting a heavy-duty vehicle, the first clutch C1 is disengaged and the second clutch C2 is locked. The engine 1 and motor 2 (including the first motor 21 and the second motor 22) differentially drive the vehicle via the planetary gear mechanism 3. This mode overcomes the problem of conventional heavy-duty vehicles requiring a starting clutch when starting. However, when the clutch is in a semi-engaged state, the clutch relies on the sliding friction of the clutch's friction plates to transmit power, resulting in incomplete engine torque transmission and difficulty in starting.

[0099] 5. (HEV) Unpowered Interrupted Shifting Process:

[0100] 1. HEV operating mode: Shift from coaxial drive first gear (first clutch C1 and second clutch C2 locked, third synchronizer S3 engaged to the left with the fifth drive gear Gh) to split-shaft drive first and second gears: The motor is unloaded, engine 1 increases torque, second clutch C2 is disengaged, first motor 21 and second motor 22 are synchronized, first synchronizer S1 engaged to the left with the first drive gear Gd, and first motor 21 and second motor 22 recover torque. Engine 1 torque is output through the first clutch C1, planetary gear mechanism 3, first input shaft 41, and first gear gearset. Torque from first motor 21 and second motor 22 is output through the second input shaft 42 and second gearset.

[0101] 2. Shifting from split-shaft drive first and second gears to coaxial drive second gear: Engine 1 is unloaded, the first and second motors 21 and 22 increase torque, the third synchronizer S3 is shifted to neutral and disengaged from the fifth drive gear Gh, the second clutch C2 is locked, and engine 1 recovers torque. Engine 1 torque is output through the planetary gear mechanism 3, the first clutch C1, the second clutch C2, the second input shaft 42, and the second gear set. Torque from the first and second motors 21 and 22 is output through the second input shaft 42 and the second gear set.

[0102] 3. Shifting from coaxial drive second gear to split-shaft drive third and second gears: Engine 1 is unloaded, first motor 21 and second motor 22 increase torque, first clutch C1 and second clutch C2 disengage, third synchronizer S3 shifts right to engage sixth drive gear Gi, and first clutch C1 locks, allowing engine 1 to recover torque. Engine 1 torque is output via first clutch C1, planetary gear mechanism 3, first input shaft 41, and third gear set. Torque from first motor 21 and second motor 22 is output via second input shaft 42 and second gear set.

[0103] 4. Shift from split-shaft drive third and second gears to split-shaft drive fourth and second gears: Engine 1 unloads, first motor 21 and second motor 22 increase torque, first clutch C1 disengages, third synchronizer S3 shifts to neutral and disengages sixth drive gear Gi, second synchronizer S2 shifts to the left and engages third drive gear Gf, first clutch C1 locks, and engine 1 recovers torque. Engine 1 torque is output through first clutch C1, planetary gear mechanism 3, first input shaft 41, and fourth-gear set. Torque from first motor 21 and second motor 22 is output through second input shaft 42 and second-gear set.

[0104] 5. Shifting from split-shaft drive fourth and second gears to split-shaft drive fourth and fifth gears: The first and second motors 21 and 22 are unloaded, the engine 1 increases torque, the first synchronizer S1 is in neutral, the first and second motors 21 and 22 are synchronized, the first synchronizer S1 shifts right and engages the second drive gear Ge, and the first and second motors 21 and 22 recover torque. The engine 1 torque is output through the first clutch C1, the planetary gear mechanism 3, the first input shaft 41, and the fourth-speed gearset. The first and second motors 21 and 22 torque is output through the second input shaft 42 and the fifth-speed gearset.

[0105] 6. Shifting from split-shaft drive fourth and fifth gears to split-shaft drive fifth and sixth gears: Engine 1 unloads, first motor 21 and second motor 22 increase torque, first clutch C1 disengages, second synchronizer S2 shifts to neutral and disengages third drive gear Gf, fourth synchronizer S4 shifts to the left and engages seventh drive gear Gj, first clutch C1 locks, and engine 1 recovers torque. Engine 1 torque is output via first clutch C1, planetary gear mechanism 3, first input shaft 41, and sixth gear set. Torque from first motor 21 and second motor 22 is output via second input shaft 42 and fifth gear set.

[0106] 7. Shifting from split-shaft drive fifth and sixth gears to split-shaft drive fifth and seventh gears: Engine 1 unloads, first motor 21 and second motor 22 increase torque, first clutch C1 disengages, fourth synchronizer S4 shifts to neutral and disengages seventh drive gear Gj, then shifts to right and engages output gear Gm. First clutch C1 locks, and engine 1 recovers torque. Engine 1 torque is output via first clutch C1, planetary gear mechanism 3, first input shaft 41, and output gear Gm. Torque from first motor 21 and second motor 22 is output via second input shaft 42 and the fifth-speed gearset.

[0107] Therefore, the shifting process can be achieved without power interruption under HEV conditions.

[0108] 6. When the drive battery is dead, the vehicle starts with engine 1:

[0109] In extremely cold weather, the drive battery is restricted from working, and the differential mode can be used for starting. The engine 1 increases the torque to drive the first input shaft 41 and at the same time drives the first motor 21 and the second motor 22 to generate electricity. After the battery is charged, the first motor 21 and the second motor 22 increase the torque and accelerate in the positive direction, and drive the vehicle to start through the first input shaft 41.

[0110] The working conditions of this embodiment can also be referred to the following table:

[0111] This system increases the total speed difference of the parallel shaft gears and can eliminate the auxiliary transmission.

[0112] The working principle of this system is further explained as follows: when the system is only in first gear, the first clutch C1 is disengaged, the clutch C2 is locked, the output shaft of the engine 1 is connected to the ring gear shaft 32, the rotating shaft of the motor 2 (in this embodiment, the motor 2 includes the first motor 21 and the second motor 22. For the convenience of description, only the motor 2 is used for description, and the same applies below) is connected to the sun gear shaft 34, the planetary carrier shaft 37 is connected to the first input shaft 41, and the engine 1 and the motor 2 are differentially driven.

[0113] If the torque of engine 1 is T eng , the torque of motor 2 is Tem =ρ·T eng , the torque T acting on the first input shaft 41 C =(1+ρ)·T eng , and then through the first gear deceleration and torque increase, the output torque T out =(1+ρ)·η1·T eng , the torque multiplier of the engine 1 is (1+ρ)·η1. Due to the characteristics of the planetary gear mechanism 3, the speed ratio of the engine 1 / ring gear shaft 32 and the first input shaft 41 / planet carrier shaft 37 is not fixed, but the torque ratio is fixed T C =(1+ρ)·T eng . For the sake of convenience, we will say that the speed ratio of engine 1 at this time is (1+ρ)·η1. This speed ratio is (1+ρ) times larger than the first gear speed ratio η1, is the maximum speed ratio of the system, and is also the state when a heavy-loaded vehicle starts. When the first clutch C1 is closed, the planetary gear mechanism 3 is locked, and the engine 1 is connected to the first input shaft 41 and rotates at the same speed; at the same time, the gearbox is engaged in the highest gear η7, and the speed ratio of engine 1 is η7. The total step difference of the system is equal to the ratio of the maximum speed ratio to the minimum speed ratio. The total step difference of this system is (1+ρ)·η max / η min =(1+ρ)·η1 / η7.

[0114] For parallel-axis gearboxes, the transmission gears must have a sufficient number of teeth to smoothly transmit torque. Transmission gears, particularly the first-gear drive gear, must have a sufficiently large module to transmit a certain amount of torque. Therefore, the gears must have a sufficient number of teeth and a large enough module, and their diameters cannot be too small. Furthermore, many other engineering factors (such as shaft diameter, gear bearing, and synchronizer arrangement) limit the minimum gear size. The center distance of a parallel-axis gearbox is a critical parameter, significantly influencing the torque transmission, weight, and size. Given a given center distance, the gearbox's total step size is limited by the minimum gear size.

[0115] In the prior art, due to the above limitations, the total step difference η of the AMT gearbox is max / η min The maximum step size cannot exceed 12, failing to achieve the 15+ step difference required for heavy-duty vehicle transmissions. Therefore, a sub-transmission is often added. The input shaft of the sub-transmission is connected to the output shaft of the main transmission, amplifying the input torque several times. The required torque is very high, resulting in high shifting costs and a high risk of failure.

[0116] While this system uses the same center distance, the total step difference of the simple gearbox is equal to η max / η min, it can reach 10 to 12. Multiplying it by the deceleration torque ratio of the planetary gearbox, the equivalent total step difference of engine 1 in this system is (1+ρ)·η max / η min The ρ value of the planetary gear mechanism 3 is commonly between 0.35 and 0.75. Therefore, the system expands the total speed differential of the engine 1 by 35% to 75%, reaching or exceeding the total differential of 15 to 20 required for heavy-duty vehicle transmissions. As a result, a sub-transmission is no longer required, which can simplify the system, reduce costs, and reduce maintenance costs.

[0117] The system can stably output maximum torque at zero vehicle speed, and has strong vehicle escape capability and heavy-load hill-start capability.

[0118] For existing heavy-duty vehicles, when the engine 1 drives the vehicle to start, the engine speed is above 1000 rpm. The wheel speed starts at zero and increases with vehicle speed. Accordingly, the transmission input shaft speed also starts at zero and gradually increases until it rotates at the same speed as the engine shaft. The engine shaft then locks with the transmission input shaft, completing the start. When there is a speed difference between the two shafts and locking is not possible, the AMT transmission must rely on clutch slippage to transmit torque. This slippage torque transfer process inevitably generates heat, which is proportional to the torque and time. Starting a heavy-duty vehicle with a heavy load requires high torque and a long duration, generating significant heat. In particular, starting a heavy-duty vehicle uphill requires higher torque and longer acceleration times, which can easily burn the clutch friction material. Some heavy-duty vehicles, such as mining trucks and dump trucks, often become stuck in potholes, gravel, and other obstacles, requiring high torque to free them. Furthermore, clutch slip torque is determined by the pressure on the clutch friction plate, which is prone to fluctuations. Excessive pressure can lock the clutch, causing a sharp drop in engine speed or even stalling the engine. Too little pressure can't transmit sufficient torque, making starting and disengaging a vehicle with a heavy load difficult. Clutch torque control is challenging, component costs are high, and control software technology is technically challenging. In short, heavy vehicles rely on clutch slip torque transmission, which is technically difficult to control, resulting in unstable torque transmission and difficulty in starting and disengaging a vehicle with a heavy load. Furthermore, the clutch friction plate wears significantly, requiring frequent replacement and maintenance, increasing operating costs and reducing production efficiency.

[0119] This system utilizes a completely new concept for heavy-load starting. The system is configured as follows: First clutch C1 is disengaged, placing planetary gear mechanism 3 in differential mode. Clutch C2 is engaged, connecting the motor 2 shaft to the sun gear shaft 34. First input shaft 41 is engaged in first gear, while second input shaft 42 is unengaged. Thus, the output shaft of engine 1 is connected to ring gear shaft 32 as input, the shaft of motor 2 is connected to sun gear shaft 34 as input, and the planetary carrier shaft 37 is connected to first input shaft 41 as output, driving the wheels via first gear.

[0120] The three axis speeds of the planetary gear mechanism 3 are subject to kinematic constraints: ρ·n S +n R =(1+ρ)·n C , the torques of the three axes of the planetary gear mechanism 3 are related by: T S =ρ·T R , and: T C =T S +T R .

[0121] At the moment of starting, the planetary carrier shaft 37 rotates at a speed n C is zero, engine 1 rotates forward and the speed is n R , the motor 2 shaft speed is -n R / ρ (reverse rotation); the output torque of engine 1 is T R =T eng , the torque of motor 2 is T S =ρ·T R =ρ·T eng , the torque of the planetary carrier shaft 37 is T C =T S +T R =(1+ρ)T eng , which is (1 + ρ) times the torque of engine 1. After the start, the torque of planetary carrier shaft 37 passes through the first gear of first input shaft 41, driving the wheels and, in turn, accelerating the vehicle. As vehicle speed increases, the speeds of first input shaft 41 and planetary carrier shaft 37 increase. Simultaneously, the speed of engine 1 remains constant, while motor 2 accelerates in the forward direction. When the speeds of motor 2 (connected to sun gear shaft 34) and first input shaft 41 (connected to planetary carrier shaft 37) equal those of engine 1 (connected to ring gear shaft 32), first clutch C1 closes and locks, connecting the output shaft of engine 1 to the gearbox input shaft, completing the start.

[0122] During the starting process, the engine 1 torque T eng , motor 2 output ρ·T eng , the torque of the first input shaft 41 is (1+ρ)T eng , after a gear deceleration and torque increase, the output torque is (1+ρ)·η1·T eng The deceleration torque increase multiple is (1+ρ)·η1, which is equivalent to the speed ratio (1+ρ)·η1. The driving force is very strong and very stable. In particular, during the entire process, there is no large amount of sliding heat, friction plate burning and other phenomena. The technically complex clutch torque control can be replaced by ordinary motor 2 control, which simplifies the control.

[0123] This system eliminates the starting clutch, completely solving the problem of clutch friction plate slippage and ablation.

[0124] AMT transmissions typically rely on clutch slip to transmit torque and propel the vehicle. Heavy-duty vehicles experience high clutch slip torque and prolonged operation, generating significant heat. This can lead to continuous erosion of the clutch friction plates, necessitating frequent maintenance or replacement. Some heavy-duty trucks require friction plate replacement every two to three months, increasing operating costs and impacting efficiency.

[0125] This system comprises an engine, motor, and planetary gearbox, forming a differential-drive starting mechanism. Leveraging the motor's reverse positive torque capability and the planetary gearbox's differential drive function, this system differentially drives heavy-loaded vehicles. Consequently, this system eliminates the starting clutch required by conventional AMTs, simplifies clutch control by eliminating clutch slippage to transfer torque, and eliminates the need for regular maintenance and friction plate replacement, reducing operational costs and improving productivity.

[0126] This system can shift gears without power interruption, solving the problem of heavy-loaded vehicles having difficulty climbing hills.

[0127] Again, when the engine 1 shifts gears, the motor 2 continues to drive and compensates for the torque, maintaining the driving force and achieving power-free interruption shifting.

[0128] Heavy vehicles, such as mining trucks, have difficulty shifting gears when climbing hills. Mining trucks often encounter situations where they need to start and climb heavily loaded roads. Typically, the transmission starts in first gear (the starting gear), then shifts to second, then third, and so on, as the vehicle speed increases. AMT shifts gears through the following steps: 1. Reducing engine torque to zero (unloading), 2. Disengaging the clutch, 3. Shifting out of the current gear, 4. Engaging the new gear, 5. Re-locking the clutch, and 6. Restoring engine torque. Shifting into the new gear takes the longest time. This process interrupts power, causing the heavy vehicle to lose traction and slow down due to the gradient. Sometimes, the steepness of the slope and the length of the shifting process can cause the heavy vehicle to decelerate significantly, making it impossible to shift into the new gear and continue climbing. This means that heavy vehicles with heavy loads climbing hills have difficulty shifting gears with AMTs, and the difficulty increases with slower speeds and the lower the gear, with shifting becoming more challenging: shifting from first gear (the starting gear) to second gear (the first driving gear) being the most challenging. If a heavy vehicle rolls back during the gear shift process, it is very likely to cause a safety accident and must be strictly prevented. When a heavy vehicle cannot shift gears while climbing a slope, it is forced to climb at a very low gear, traveling very slowly and significantly affecting production efficiency.

[0129] When shifting gears while climbing a hill with a heavy load, the engine 1 and the drive motor drive and shift gears alternately, achieving shifting without power interruption, avoiding rolling down the slope, and preventing safety accidents. The process is as follows:

[0130] a) Switching from the "Starting State" to the "First Drive Gear": When the vehicle starts, the gearbox engages first gear. Engine 1 and motor 2 are differentially driven via the planetary gear mechanism 3. Engine 1's torque is amplified by a factor of (1+ρ)·η1, which translates to a speed ratio of (1+ρ)·η1. This represents the starting state of the system (corresponding to first gear in an AMT). As vehicle speed increases and motor 2's speed approximately equals engine 1's, first clutch C1 locks, allowing engine 1 to directly drive in first gear. The speed ratio of engine 1 is η1, representing the system's "first drive gear," or first gear. Once first clutch C1 is locked, engine 1 can independently drive in first gear. Simultaneously, clutch C2 disengages, engaging second gear, with motor 2 driven via the second input shaft 42 and the second gear. This transition from the "Starting State ((1+ρ)·η1)" to the "First Drive Gear (η1)" is completely smooth, maintaining the same starting driving force and preventing vehicle deceleration.

[0131] b) Shifting from First Gear to Second Gear: When further upshifting is required, the shifting steps are as follows: 1. Engine 1 unloads torque, while motor 2 compensates for the torque, continuing to drive the vehicle through second gear. 2. First gear is disengaged. 3. Lockup clutch C2 is engaged, locking engine 1 and motor 2 together. 4. Engine 1 recovers torque, driving through second input shaft 42 and second gear, achieving a reduction ratio of η2, completing the upshift. The shifting process from first drive gear η1 to second drive gear η2 eliminates the need for a gear engagement step, significantly shortening shift time. Motor 2 maintains power, enabling smooth shifting of heavy vehicles without slowing down or even rolling down a slope.

[0132] c) Shifting from Second Gear to Third Gear: When further upshifting is required, the shifting steps are as follows: 1. Engine 1 unloads torque, while motor 2 compensates for torque, continuing to drive the vehicle through the second gear. 2. Release first clutch C1 and second clutch C2. 3. Engage third gear η3. 4. Close and lock first clutch C1, locking engine 1 to first input shaft 41. 5. Engine 1 recovers torque, driving through second input shaft 42 and second gear, with a reduction ratio of η2, completing the upshift. The shifting process from second drive gear η2 to third drive gear η3 eliminates the need for a gear shift, shortening shift time. Motor 2 maintains power, allowing heavy vehicles to shift smoothly, achieving power-free shifting without slowing down or even rolling downhill.

[0133] d) Shifting from third gear to fourth gear: The shifting steps are as follows: 1. Engine 1 unloads torque, while motor 2 compensates for the torque, continuing to drive the vehicle through second gear; 2. Release first clutch C1; 3. Disengage third gear η3; 4. Engage fourth gear η4; 5. Close and lock first clutch C1, locking engine 1 to first input shaft 41; 6. Engine 1 recovers torque, driving through first input shaft 41 and fourth gear, achieving a reduction ratio of η4, completing the upshift. Throughout the shifting process, motor 2 continuously drives the wheels through second input shaft 42 and second gear, allowing heavy vehicles to shift smoothly without slowing down or even rolling down a slope. In fact, at this point, the vehicle speed is already high and the transmission is in a high gear, making shifting difficult a non-issue.

[0134] If the gearbox continues to shift up, it will switch from "medium-low speed" to "medium-high speed", which is no longer within the scope of heavy-load climbing steep slopes. However, the shifting process is still described as follows:

[0135] e) Shifting from 4th to 5th Gear: When the system shifts into 4th gear and continues accelerating, Motor 2 must first shift from 2nd to 5th gear: 1. Motor 2 unloads torque, while Engine 1 compensates for torque and continues driving; 2. Disengage 2nd gear; 3. Engage 5th gear; 4. Motor 2 recovers torque. When Engine 1 shifts to 5th gear, the shifting steps are as follows: 1. Engine 1 unloads torque, while Motor 2 compensates for torque, continuing to drive the vehicle through 5th gear; 2. Disengage 4th gear; 3. Engage and lock the second clutch C2, locking Engine 1 and Motor 2 together; 4. Engine 1 recovers torque, driving through the second input shaft 42 and 5th gear, achieving a reduction ratio of η5, completing the shift. This shift from 4th to 5th gear eliminates the need for a gear shift, significantly shortening shift time. Motor 2 maintains drive, enabling smooth shifting of heavy vehicles without power interruption.

[0136] f) Shifting from fifth gear to sixth gear: When further upshifting is required, the shifting steps are as follows: 1. Engine 1 unloads torque, while motor 2 compensates for torque, continuing to drive the vehicle through fifth gear; 2. Release first clutch C1 and second clutch C2; 3. Engage sixth gear η3; 4. Close and lock first clutch C1, locking engine 1 to first input shaft 41; 5. Engine 1 recovers torque, driving through first input shaft 41 and sixth gear, achieving a reduction ratio of η6, completing the upshift. During the shifting process, the step of disengaging gears is eliminated, shortening shift time. Motor 2 remains driven, allowing heavy vehicles to shift smoothly and achieve shifting without power interruption.

[0137] g) Shifting from Sixth Gear to Seventh Gear: The shifting process is as follows: 1. Engine 1 unloads torque, while motor 2 compensates for torque, continuing to drive the vehicle through fifth gear; 2. Release first clutch C1; 3. Disengage sixth gear η6; 4. Engage seventh gear η7; 5. Close and lock first clutch C1, locking engine 1 to first input shaft 41; 6. Engine 1 recovers torque, driving through first input shaft 41 and seventh gear, achieving a reduction ratio of η7, completing the upshift. Throughout the shifting process, motor 2 continuously drives the wheels through second input shaft 42 and fifth gear, enabling smooth shifting of heavy vehicles without power interruption.

[0138] Embodiment 2, as shown in Figure 2, is a hybrid power system suitable for heavy vehicles. The difference from embodiment 1 is that this embodiment also includes a reduction mechanism 5, which includes a reduction mechanism input shaft 51 and a reduction mechanism output shaft 52. The reduction mechanism input shaft 51 is connected to the gearbox output shaft 43 of the gearbox 4. In this embodiment, the reduction mechanism input shaft 51 and the gearbox output shaft 43 are connected as a whole, and the central axes of the reduction mechanism input shaft 51 and the reduction mechanism output shaft 52 are arranged to overlap.

[0139] The reduction mechanism 5 also includes two transmission shafts 53, both of which are parallel to the reduction mechanism output shaft 52. A fourth gear 54 is fixedly connected to the reduction mechanism input shaft 51, and a fifth gear 55 is fixedly connected to the reduction mechanism output shaft 52. A sixth gear 56 and a seventh gear 57 are fixedly connected to each transmission shaft 53. The sixth gear 56 is meshed with the fourth gear 54, and the seventh gear 57 is meshed with the fifth gear 55.

[0140] The various working conditions and working principles of this embodiment are the same as those of the first embodiment, except that after deceleration by the speed reduction mechanism 5 , the output torque of the speed reduction mechanism output shaft 52 increases.

[0141] Embodiment 3, as shown in Figure 3, is a hybrid power system suitable for heavy vehicles. It differs from Embodiment 1 in that: this embodiment also includes a reduction mechanism 5, the reduction mechanism 5 includes a reduction mechanism input shaft 51 and a reduction mechanism output shaft 52, the reduction mechanism input shaft 51 is connected to the gearbox output shaft 43 of the gearbox 4, and the reduction mechanism input shaft 51 and the gearbox output shaft 43 in this embodiment are connected as a whole, and the central axes of the reduction mechanism input shaft 51 and the reduction mechanism output shaft 52 are arranged to overlap.

[0142] The reduction mechanism 5 also includes a second ring gear 5a, a second sun gear 5b and three second planetary gears 5c. Each second planetary gear 5c is simultaneously engaged with the second ring gear 5a and the second sun gear 5b. The three second planetary gears 5c are connected to the second planetary carrier 5d. The second planetary carrier 5d is fixedly connected to the reduction mechanism output shaft 52. The second ring gear 5a is fixedly connected to the housing of the reduction mechanism 5. The second sun gear 5b is fixedly connected to the reduction mechanism input shaft 51.

[0143] The various working conditions and working principles of this embodiment are the same as those of the first embodiment, except that after deceleration by the speed reduction mechanism 5 , the output torque of the speed reduction mechanism output shaft 52 increases.

[0144] Embodiment 4, as shown in Figure 4, is a hybrid power system suitable for heavy vehicles. It differs from Embodiment 1 in that: the output shaft of the engine 1 is connected to the planetary carrier shaft 37, the second input shaft 42 is connected to the sun gear shaft 34 through the second clutch C2, the ring gear shaft 32 is connected to the first output shaft 41 and rotates simultaneously, the ring gear shaft 32 and the ring gear 31 are fixedly connected as one body, and the first clutch C1 is arranged between the ring gear 31 (ring gear shaft 32) and the sun gear shaft 34.

[0145] This embodiment can achieve technical effects similar to those of the first embodiment.

[0146] Embodiment 5, as shown in Figure 5, is a hybrid power system suitable for heavy vehicles. It differs from Embodiment 1 in that: the output shaft of the engine 1 is connected to the sun gear shaft 34, and the second input shaft 42 is connected to the ring gear 31 (ring gear shaft 32) through the second clutch C2. In this embodiment, the ring gear shaft 32 is integrated with the ring gear 31, and the ring gear shaft 32 is replaced by the ring gear 31. The planetary carrier shaft 37 is connected to the first input shaft 41 and can rotate simultaneously; the first clutch C1 is arranged between the ring gear 31 (ring gear shaft 32) and the sun gear shaft 34.

[0147] This embodiment can achieve technical effects similar to those of the first embodiment.

[0148] Although the present invention has been specifically shown and described in conjunction with preferred embodiments, it should be understood by those skilled in the art that various changes in form and details may be made to the present invention without departing from the spirit and scope of the invention as defined by the appended claims, and all such changes are within the scope of protection of the present invention.

Claims

1. A hybrid power system applicable to heavy vehicles, comprising an engine and a motor, characterized in that: It further includes a planetary gear mechanism, a first clutch, a second clutch and a gearbox. The planetary gear mechanism includes at least three shafts, and the central axes of all the shafts of the planetary gear mechanism overlap; The gearbox is provided with a first input shaft, a second input shaft, a gearbox output shaft and at least one intermediate shaft. The central axes of the first input shaft and the second input shaft overlap. The intermediate shaft is parallel to the first input shaft. The engine output shaft is connected to one of the shafts of the planetary gear mechanism. The second input shaft is connected to another shaft of the planetary gear mechanism through the second clutch. Another shaft of the planetary gear mechanism is connected to the first input shaft and can rotate simultaneously. The motor rotating shaft is connected to the second input shaft; The first clutch is arranged between any two shafts of the planetary gear mechanism; Synchronizers are installed on both the first input shaft and the second input shaft, and driving gears are sleeved thereon. A plurality of driven gears are fixedly connected to the intermediate shaft. At least one reverse gear is also installed on the gearbox, and an output gear is fixedly connected to the gearbox output shaft; The reverse gear meshes with one of the driven gears on the intermediate shaft and one of the driving gears on the first input shaft at the same time. The output gear meshes with one of the driven gears on the intermediate shaft. Each of the driving gears on the first input shaft, except one driving gear that meshes with the reverse gear, meshes with one of the driven gears on the intermediate shaft. The remaining driven gears on the intermediate shaft respectively mesh with the driving gears on the second input shaft. By cooperating with the position switching of the plurality of synchronizers, the gearbox forms a neutral gear, a reverse gear and a plurality of forward gears; When the heavy vehicle starts, the first clutch disengages, the second clutch locks, and the engine and the motor drive the vehicle differentially through the planetary gear mechanism.

2. The hybrid power system applicable to heavy vehicles according to claim 1, wherein: The planetary gear mechanism includes three shafts, namely a ring gear shaft, a sun gear shaft and a planet carrier shaft. The central axes of the ring gear shaft, the sun gear shaft and the planet carrier shaft overlap. The first clutch is arranged between any two of the ring gear shaft, the sun gear shaft and the planet carrier shaft. The central axes of the first input shaft and the second input shaft overlap with the central axis of the planet carrier shaft.

3. A hybrid power system applicable to heavy vehicles according to claim 2, characterized in that: The engine output shaft is connected to the ring gear shaft; the second input shaft is connected to the sun gear shaft through the second clutch. The first input shaft is connected to the planet carrier shaft and can rotate simultaneously. The first clutch is arranged between the sun gear shaft and the ring gear shaft; Or the engine output shaft is connected to the planet carrier shaft, the second input shaft is connected to the sun gear shaft through the second clutch. The ring gear shaft is connected to the first output shaft and can rotate simultaneously. The first clutch is arranged between the ring gear shaft and the sun gear shaft; Or the engine output shaft is connected to the sun gear shaft, the second input shaft is connected to the ring gear shaft through the second clutch. The planet carrier shaft is connected to the first input shaft and can rotate simultaneously. The first clutch is arranged between the ring gear shaft and the sun gear shaft.

4. A hybrid power system applicable to heavy vehicles according to claim 1, wherein: The motor rotating shaft is connected to the second input shaft through a speed reduction assembly.

5. The hybrid power system applicable to heavy vehicles according to claim 4, characterized in that: There are two motors, namely a first motor and a second motor; The first motor rotating shaft is connected to the second input shaft through a first speed reduction assembly. The first speed reduction assembly includes a first gear fixedly connected to the first motor rotating shaft and a third gear fixedly connected to the second input shaft. The first gear meshes with the third gear; The second motor rotating shaft is connected to the second input shaft through a second reduction assembly. The second reduction assembly includes a second gear fixedly connected to the second motor rotating shaft and a third gear fixedly connected to the second input shaft. The second gear meshes with the third gear.

6. The hybrid power system applicable to heavy vehicles according to claim 1, characterized in that: There are two intermediate shafts, and a plurality of driven gears are fixedly connected to both intermediate shafts; the two intermediate shafts are symmetrically arranged with respect to the first input shaft.

7. A hybrid power system applicable to heavy vehicles according to claim 1, characterized in that: Two driving gears are sleeved on the second input shaft, namely a first driving gear and a second driving gear. The first driving gear meshes with a driven gear fixedly connected to an intermediate shaft, and the second driving gear meshes with another driven gear fixedly connected to an intermediate shaft. The synchronizer on the second input shaft can be engaged with the first driving gear or the second driving gear or not engaged with either the first driving gear or the second driving gear.

8. A hybrid power system applicable to heavy vehicles according to claim 1, characterized in that: Three synchronizers are installed on the first input shaft. One of the synchronizers can be engaged with one of the driving gears on the first input shaft or with the output gear or not engaged with either the driving gear on the first input shaft or the output gear. The other synchronizers on the first input shaft can be engaged with the driving gears on the first input shaft on both sides of it or not engaged.

9. A hybrid power system applicable to heavy vehicles according to any one of claims 1 to 8, characterized in that: It further includes a reduction mechanism, which includes a reduction mechanism input shaft and a reduction mechanism output shaft. The reduction mechanism input shaft is connected to the output shaft of the gearbox.

10. A hybrid power system applicable to heavy vehicles according to claim 9, characterized in that: The reduction mechanism input shaft is integrated with the output shaft of the gearbox. The central axes of the reduction mechanism input shaft and the reduction mechanism output shaft are overlapped. The reduction mechanism further includes two transmission shafts. A fourth gear is fixedly connected to the reduction mechanism input shaft, and a fifth gear is fixedly connected to the reduction mechanism output shaft. A sixth gear and a seventh gear are fixedly connected to each transmission shaft. The sixth gear meshes with the fourth gear, and the seventh gear meshes with the fifth gear.

11. A hybrid power system applicable to heavy vehicles according to claim 9, characterized in that: The reduction mechanism further includes a second ring gear, a second sun gear and a plurality of second planet gears. Each second planet gear meshes with the second ring gear and the second sun gear at the same time. The plurality of second planet gears are connected to the second planet carrier. The second planet carrier is fixedly connected to the reduction mechanism output shaft. The second ring gear is fixedly connected to the reduction mechanism housing. The second sun gear is fixedly connected to the reduction mechanism input shaft. The reduction mechanism input shaft is integrated with the output shaft of the gearbox. The central axes of the reduction mechanism input shaft and the reduction mechanism output shaft are overlapped.

Images