Hybrid power system suitable for heavy vehicle

Abstract

The utility model discloses a hybrid power system suitable for a heavy vehicle. The hybrid power system comprises an engine, a motor, a planetary gear mechanism, a first clutch, a second clutch and a gearbox. The planetary gear mechanism at least comprises three shafts, and the central axes of all the shafts are overlapped; a first input shaft, a second input shaft, a gearbox output shaft and an intermediate shaft are arranged on the gearbox, the output shaft of the engine is connected with one shaft of the planetary gear mechanism, the second input shaft is connected with the other shaft of the planetary gear mechanism through a second clutch, and the other shaft of the planetary gear mechanism is connected with the first input shaft and can rotate simultaneously; the motor shaft is connected with the second input shaft; the first clutch is arranged between any two shafts of the planetary gear mechanism; the first input shaft and the second input shaft are both provided with synchronizers and sleeved with driving gears, and the middle shaft is fixedly connected with a plurality of driven gears. When the vehicle starts, the engine and the motor drive the vehicle in a differential mode through the planetary gear mechanism. The utility model is convenient for starting and getting out of trouble of the heavy vehicle, and has higher cost performance.

Description

Technical Field

[0001] This utility model relates to the field of hybrid vehicle manufacturing technology, and in particular to a hybrid system suitable for heavy-duty vehicles. Background Technology

[0002] Upgrading traditional internal combustion engine heavy-duty vehicles to hybrid powertrains is urgently needed. Hybrid powertrains can effectively meet the carbon emission and low fuel consumption requirements of heavy-duty trucks, and have a broad market potential. The key component of hybrid vehicles is the hybrid transmission.

[0003] Heavy-duty vehicles are massive, typically weighing over 15 tons, and some even exceeding 100 tons. They require significant torque for acceleration and hill climbing, with transmission input torque exceeding 2000 Nm and output torque exceeding 30000 Nm. Wheel-side torque can reach 100,000–200,000 Nm, necessitating a transmission capable of transmitting such high torque and possessing a large reduction-to-torque ratio. Their operating speed needs to reach around 100 km / h, requiring high wheel speeds and a smaller reduction ratio. This necessitates a large gear ratio range (the ratio of the maximum to the minimum gear ratio), typically exceeding 15. In comparison, passenger car transmissions generally have input torque of 100–400 Nm, wheel-side torque of 2000–3000 Nm, and a gear ratio range generally not exceeding 10. Due to these significant differences in requirements, the hybrid transmissions needed for heavy-duty vehicles differ considerably from the hybrid technology widely used in passenger cars.

[0004] In many cases, heavy-duty vehicles use hybrid transmission systems that are improvements on the transmission itself. These are add-on hybrid transmission systems, meaning an electric motor is added to the transmission input, with a clutch between the motor and the engine; this is commonly known as a P2 hybrid transmission. The transmission can be an AMT (automated manual transmission), AT (automatic transmission), or DCT (dual-clutch transmission).

[0005] US Patent Application US2014 / 0144288 discloses a P2+AMT hybrid system. The system consists of an electric motor (EM), main transmissions 8 and 10, and a secondary transmission 12. Main transmissions 8 and 10 have six forward gears, while the secondary transmission 12 uses a planetary gear set and synchronizers to form a two-speed transmission mechanism, resulting in a total of 6 × 2 = 12 gears. This hybrid transmission offers several advantages: it can output high torque to meet power requirements, drive vehicles at high speeds, and significantly reduce fuel consumption; its simple construction, adding an electric motor to an AMT transmission, results in low manufacturing and operating costs; synchronizer engagement and parallel shaft gear transmission provide high torque and efficiency; it shares most components with widely used manual transmissions (MT) and automatic transmissions (AMT), indicating mature technology and a complete supply chain; it can be manufactured on production lines based on MT or AMT transmissions, requiring less initial investment in factory buildings and equipment, and so on. However, this type of transmission mechanism also has some weaknesses: when starting a heavy-duty vehicle, the system relies on the friction of the clutch plates to transmit the torque output by the engine, which can easily burn the friction plates and prevent the full torque from being output, leading to problems such as difficulty climbing hills and getting out of trouble under heavy loads; due to the heavy load of heavy-duty vehicles, the gear ratio requirements of the transmission are high, so a secondary transmission is needed to adjust the high / low speeds, and because the torque value to be transmitted at the secondary transmission is large, the cost of the shifting mechanism is high and it is 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 engaged again, which inevitably interrupts the power supply, and heavy-duty vehicles may slip when climbing hills, posing a safety hazard.

[0006] US Patent 10576814 discloses a hybrid power system including an engine 4, a first motor 14, a second motor 16, a first planetary gear set 10, a second planetary gear set 12, a gearbox 19, and a sub-gearbox 11. Gearbox 19 has two input shafts 34 and 36. It features high starting torque, strong heavy-load hill-climbing and off-road capabilities, and eliminates the need for clutch slippage transmission torque. During gear shifting, one motor maintains drive while the other motor drives the engine to shift, achieving uninterrupted gear shifting. Gearbox 19 has several gears, and sub-gearbox 11 has two gears, widening the gear ratio range. Employing a dual-input sub-gearbox, it can achieve uninterrupted gear shifting throughout the entire process. However, this system involves two motors, two planetary gear sets, and a structurally and controllably complex sub-gearbox, resulting in a complex construction and high cost.

[0007] CN115008997A discloses "A dual-motor multi-gear hybrid system suitable for heavy-duty trucks," which includes a housing, generator, drive motor, engine, axle, and dual planetary gear set mechanism. 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 installed on the housing. The system achieves continuously variable transmission (CVT) by adjusting the speed of the rear sun gear through the generator, improving vehicle comfort; decoupling engine speed and vehicle speed allows for continuous operation within the economic range, improving vehicle economy; torque compensation by the generator and engine ensures uninterrupted power during gear shifts, improving vehicle safety; and it improves vehicle power while meeting the requirements of uninterrupted power during gear shifts, 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 mainly used in the heavy-duty truck field, the addition of one motor and two planetary gear sets significantly increases costs.

[0008] CN115773341A discloses "a continuously variable transmission (CVT) with uninterrupted power output," which includes a transmission body. From the input end to the output end of the central shaft, a first shifting device, a second shifting device, a third shifting device, and a fourth shifting device are sequentially arranged. The second shifting device is located between the tenth and eleventh transmission gears of the first hollow shaft. The third shifting device is located between the fifth and sixth transmission gears of the second hollow shaft. The fourth shifting device is located at the left end of the front planetary carrier. The rear planetary carrier is connected to the second hollow shaft and the central shaft respectively via bearings and splines. The front planetary carrier is connected to the second hollow shaft via bearings. The advantages of this invention are: reduced shifting frequency, uninterrupted power output during vehicle shifting, continuously variable transmission without shift shock, and improved vehicle comfort, economy, and safety. Compared to the traditional P2 parallel hybrid system, this system adds an electric motor, planetary gear set, and a more complex shaft system, which solves problems such as power interruption during gear shifting, difficulty in climbing hills, and clutch slippage loss during starting conditions, but also greatly increases the system cost.

[0009] US Patent 7082850B2 discloses a hybrid power system employing 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), which can achieve uninterrupted gear shifting and improve vehicle safety. However, for heavy-duty vehicles, the DCT also requires a secondary transmission, making completely uninterrupted gear shifting impossible. Furthermore, the dual-clutch module of the DCT is extremely expensive, posing significant technical challenges for use in heavy-duty vehicles; currently, no mass-produced heavy-duty trucks equipped with a P2+DCT hybrid transmission have been found.

[0010] US Patent 9108635B2 discloses a hybrid power system employing a P2+AT transmission (with an electric motor added to the input of the AT transmission, and a clutch between the motor and the engine). Because AT transmissions have powerful torque converters, their heavy-load hill-start ability and off-road capability are significantly stronger than the clutches of AMT and DCT transmissions; furthermore, ATs can achieve uninterrupted gear shifting. However, high-torque AT transmissions are very expensive, and there is currently a lack of high-torque AT transmissions on the market, especially in China. The R&D costs, such as the investment in new molds, are extremely high. Therefore, the development of a P2+AT hybrid transmission system for heavy-duty vehicles lacks the basic technological foundation and has poor cost-effectiveness. Utility Model Content

[0011] The technical problem to be solved by this utility model is to provide a hybrid power system suitable for heavy vehicles. It has a high cost performance when applied to heavy vehicles, facilitates the starting and getting out of trouble of heavy vehicles, and can achieve gear shifting without power interruption, resulting in good driving smoothness.

[0012] To achieve the above objectives, the technical solution of this utility model is: a hybrid power system suitable for heavy vehicles, including an engine and an electric motor, and further including a planetary gear mechanism, a first clutch, a second clutch and a gearbox, wherein the planetary gear mechanism includes at least three shafts and the central axes of all 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 of the shafts of the planetary gear mechanism. The second input shaft is connected to another shaft of the planetary gear mechanism through 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 located between any two shafts of the planetary gear mechanism;

[0015] Synchronizers and drive gears are installed on both the first and second input shafts. Multiple driven gears are fixedly connected to the intermediate shaft. At least one reverse gear is also installed on the gearbox. An output gear is fixedly connected to the output shaft of the gearbox.

[0016] The reverse gear meshes simultaneously with a driven gear on the intermediate shaft and a driving gear on the first input shaft. The output gear meshes with one of the driven gears on the intermediate shaft. Except for one driving gear meshing with the reverse gear, each of the driving gears on the first input shaft meshes with a driven gear on the intermediate shaft. The remaining driven gears on the intermediate shaft mesh with driving gears on the second input shaft. Combined with the position switching of multiple synchronizers, the gearbox can form neutral, reverse gear, and multiple forward gears.

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

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

[0019] Further preferably, 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, and the first clutch is located between the sun gear shaft and the ring gear shaft;

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

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

[0022] In a further improvement, the motor shaft is connected to the second input shaft via a reduction gear assembly. Currently, heavy-duty vehicles use large-displacement diesel engines with a narrow speed range, typically 1000rpm-2800rpm, while hybrid systems typically use motors that can reach around 10000rpm, offering better performance / efficiency at higher speeds. If the motor is directly connected to the engine, it cannot operate within its high-efficiency range. This invention connects the motor output shaft to the engine via a reduction gear assembly, allowing the motor to operate within its high-efficiency range and improving its efficiency. This invention is designed for heavy-duty vehicle hybrid systems, which require high transmission torque and significant torque demands in pure electric operation. By connecting the motor output shaft to the second input shaft via a reduction gear assembly, the torque can be amplified, meeting the torque requirements of pure electric drive in heavy-duty vehicles.

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

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

[0025] There are two intermediate shafts, each with multiple driven gears fixedly connected to it. This structure is more conducive to power transmission. Preferably, the two intermediate shafts are symmetrically arranged with respect to the first input shaft.

[0026] Preferably, the second input shaft is fitted with two drive gears, namely a first drive gear and a second drive gear. The first drive gear meshes with a driven gear fixed to the intermediate shaft, and the second drive gear meshes with another driven gear fixed to the intermediate shaft. The synchronizer on the second input shaft can engage with the first drive gear or the second drive gear, or not engage with either the first drive gear or the second drive gear.

[0027] Preferably, the first input shaft is equipped with three synchronizers. One of the synchronizers can engage with one of the drive gears on the first input shaft, or with the output gear, or not engage with either the drive gear or the output gear on the first input shaft. The other synchronizers on the first input shaft can engage with the drive gears on the first input shaft located on either side of them, or not engage with either of them.

[0028] Furthermore, the reverse gear is fixedly connected to the 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 reverse gear shafts is the same as the number of intermediate shafts.

[0029] Further improvements include a reduction mechanism, which comprises an input shaft and an output shaft, with the input shaft connected to the gearbox output shaft. The output torque and speed of the hybrid transmission system are adjusted by changing the speed ratio of the reduction mechanism to meet the needs of different vehicle models. Furthermore, modular design and production are possible, reducing corresponding R&D and production costs.

[0030] As a preferred embodiment, the input shaft of the reduction mechanism is integrated with the output shaft of the gearbox, and the central axes of the input shaft and the output shaft overlap. The reduction mechanism includes two drive shafts, with a fourth gear fixedly connected to the input shaft and a fifth gear fixedly connected to the output shaft. A sixth gear and a seventh gear are fixedly connected to each drive shaft, with the sixth gear meshing with the fourth gear and the seventh gear meshing with the fifth gear.

[0031] As another preferred embodiment, the reduction mechanism includes a second ring gear, a second sun gear, and multiple second planet gears. Each second planet gear meshes with both the second ring gear and the second sun gear. The multiple second planet gears are connected to a second planet carrier. The second planet carrier is fixed to the output shaft of the reduction mechanism. The second ring gear is fixed to the housing of the reduction mechanism. The second sun gear is fixed to the input shaft of the reduction mechanism. The input shaft of the reduction mechanism is integrated with the output shaft of the gearbox. The central axes of the input shaft and the output shaft of the reduction mechanism overlap.

[0032] The beneficial effects of this utility model are as follows:

[0033] 1. This system's engine and motor are driven differentially via a planetary gear mechanism, replacing the starting clutch. It provides full torque drive for vehicle starting, with stable output torque. Under full torque conditions, it can switch from starting to first gear. During engine shifting, the motor compensates for engine torque and continues driving, maintaining continuous driving force. This facilitates starting and extricating heavy vehicles from difficult situations, avoiding problems such as difficulty climbing hills and extricating themselves from difficult conditions common in existing heavy vehicles. Furthermore, by replacing the traditional starting clutch, it avoids the problems of existing heavy vehicles relying on clutch friction plates for torque transmission, which can easily burn out the friction plates and prevent the output of full torque.

[0034] 2. This system utilizes a planetary gear mechanism to increase the gear ratio range. Without an auxiliary gearbox, the gear ratio range can reach the 15-20 range required for heavy-duty vehicles. Heavy-duty vehicle gearboxes require a gear ratio range of over 15, and most heavy-duty vehicle AMT gearboxes require an auxiliary gearbox to achieve this. The auxiliary gearbox has a high input torque, placing a heavy load on the shifting mechanism, increasing the load and complexity of the shifting actuator, and raising costs. This system eliminates the auxiliary gearbox, reducing the load on its shifting components, simplifying the technical difficulty of shifting devices (clutch / synchronizer), improving reliability, achieving uninterrupted power shifting throughout the entire process, and simultaneously reducing costs.

[0035] This system uses a planetary gear mechanism to increase the speed ratio range, achieving a speed ratio span of 7+1 (7 actual gear positions of the hybrid gearbox + 1 differential gear position of the planetary gear mechanism) that is the same as that of existing 2×4×2 or 6×2 gearboxes. This greatly improves the integration and effectively reduces space and weight.

[0036] 3. This system utilizes the dual input shaft feature of the gearbox, with the engine and drive motor alternately driving and shifting gears, achieving uninterrupted gear shifting and avoiding problems such as difficulty shifting uphill or even slipping on slopes. The dual power sources enable smooth switching between operating conditions. The engine is one power source, and the motor is the other. When a gear shift is needed, the motor first drives the engine through the existing gear, shifting into the new gear; then, the engine drives the engine through the new gear to complete the gear shift. Alternatively, the engine first drives the engine through the existing gear, shifting into the new gear; then, the motor drives the engine through the new gear to complete the gear shift, achieving uninterrupted gear shifting and improved driving smoothness.

[0037] 4. This system can add additional gears, improving engine fuel consumption; it can achieve partial continuous gear shifting, reducing fuel consumption in urban roads. In terms of application scenarios, this system is very suitable for medium and heavy-duty commercial vehicles, increasing the vehicle's ability to get out of trouble. Employing differential mode allows heavy-duty trucks to output maximum torque at zero speed, greatly increasing their ability to start on inclines and get out of difficult situations. Uninterrupted gear shifting solves the problem of vehicle rollback due to power interruption during gear shifting on steep slopes. The modular design allows for the matching of more engines, meeting the needs of more vehicle models.

[0038] 5. Compared to the "P2 + AMT transmission" hybrid system, this system has a similar cost, but completely overcomes the biggest drawback of the AMT transmission—power interruption during gear shifts. In terms of design philosophy, it abandons the traditional "add-on" approach. The motor is not simply attached to the transmission, but rather integrated with it. It fully utilizes the characteristics of the added motor, treating the entire hybrid system as a dual-power system (engine and motor). Utilizing the dual-channel characteristics 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 difficulty. Furthermore, the system's requirements for synchronizer engagement time are reduced, simplifying the engagement mechanism and lowering costs. This completely solves the problem of smooth gear shifting.

[0039] 6. Compared to the "P2+AT transmission" or "P2+DCT transmission" systems, this system offers the same or even better driving comfort, but with a significant cost advantage and high cost-effectiveness. Through modular design, the hybrid system can meet the powertrain requirements of a wider range of heavy-duty vehicle models.

[0040] 7. This system increases the total stage difference of the hybrid transmission and eliminates the auxiliary transmission, resulting in a greater cost advantage and a more flexible overall structural layout. Attached Figure Description

[0041] Figure 1This is a schematic diagram of the first embodiment of this utility model;

[0042] Figure 2 This is a schematic diagram of the second embodiment of the present invention;

[0043] Figure 3 This is a schematic diagram of the third embodiment of this utility model;

[0044] Figure 4 This is a schematic diagram of the fourth embodiment of this utility model;

[0045] Figure 5 This is a schematic diagram of the fifth embodiment of this utility model. Detailed Implementation

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

[0047] Example 1 Figure 1 As shown, a hybrid power system suitable for heavy-duty vehicles includes an engine 1, an electric 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: 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 planet 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 planet gears 35 are connected to the planet carrier 36, and the planet carrier shaft 37 is fixedly connected to the planet carrier 36, 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 overlap. The sun gear shaft 34 is a hollow shaft and is fitted onto the planet carrier shaft 37.

[0048] Planetary gear mechanisms can take many forms, each including at least three shafts. These can be a sun gear shaft, a planet carrier shaft, and a ring gear shaft; or 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. The characteristics and functions of various forms of planetary gear mechanisms are similar and they can be substituted for each other. This application uses a planetary gear mechanism 3, including a ring gear shaft 31, a sun gear shaft 33, and a planet carrier shaft 37, as an example to illustrate the working principle of the system; the working principle of this system is also applicable to other forms of 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 overlapped. In this embodiment, the central axes of the first input shaft 41 and the second input shaft 42 are also overlapped with the central axis of the planetary carrier shaft 37. The second input shaft 42 is a hollow shaft and is sleeved on the first input shaft 41. The intermediate shafts 44 are parallel to the first input shaft 41. 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 gear ring shaft 32. The output shaft of the engine 1 can also be integrated with the gear ring shaft 32.

[0050] Motor 2 is connected to the second input shaft 42. Typically, the maximum speed of a motor is much higher than the output shaft speed of the engine, and the size, weight, and cost of the motor are linearly related to its torque. In this embodiment, it is preferable to connect a set of reduction gears between motor 2 and the second input shaft 42 to increase the output torque of motor 2 and 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 arrangement. Therefore, in this embodiment, it is preferable that there are two motors 2, namely a first motor 21 and a second motor 22; the shaft of the first motor 21 is connected to the second input shaft 42 through a first reduction assembly 2a. The first reduction assembly 2a includes a first gear Ga fixed to the shaft of the first motor 21 and a third gear Gc fixed to the second input shaft 42, with the first gear Ga and the third gear Gc meshing.

[0051] The 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 fixed to the shaft of the second motor 22 and a third gear Gc fixed to the second input shaft 42. The second gear Gb and the third gear Gc mesh with each other.

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

[0053] The second input shaft 42 is equipped with a first synchronizer S1 and fitted with a first drive gear Gd and a second drive gear Ge. The first synchronizer S1 can engage with the first drive gear Gd or the second drive gear Ge, or it can not engage with either the first drive gear Gd or the second drive gear Ge.

[0054] The first input shaft 41 is equipped with three synchronizers: the second synchronizer S2, the third synchronizer S3, and the fourth synchronizer S4. Five drive gears are also fitted onto the first input shaft 41: the third drive gear Gf, the fourth drive gear Gg, the fifth drive gear Gh, the sixth drive gear Gi, and the seventh drive gear Gj. Two intermediate shafts 44 are each fixedly connected with a first driven gear G1, a second driven gear G2, a third driven gear G3, a fourth driven gear G4, a fifth driven gear G5, a sixth driven gear G6, a seventh driven gear G7, and an eighth driven gear GR. The gearbox output shaft 4... 3. An output gear Gm is fixedly connected to the upper part; the fourth synchronizer S4 can engage with the seventh driving gear Gj or the output gear Gm, or not engage with either the seventh driving gear Gj or the output gear Gm; the second synchronizer S2 can engage with the third driving gear Gf located on both sides of it, or the fourth driving gear Gg, or not engage with either the third driving gear Gf or the fourth driving gear Gg; the third synchronizer S3 can engage with the fifth driving gear Gh located on both sides of it, or the sixth driving gear Gi, or not engage with either the fifth driving gear Gh or the sixth driving gear Gi.

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

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

[0057] The two intermediate shafts 44 are symmetrically arranged with respect to the first input shaft 41, and the two reverse gear shafts 45 are also symmetrically arranged with respect 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 through the planetary gear mechanism 3; this enables idle start-stop and idle power generation.

[0060] In this state, the first synchronizer S1 of gearbox 4 is in the neutral position and in neutral, while the third synchronizer S3 can engage the left side and connect with the fifth drive gear Gh to engage 1st 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 is engaged with the second input shaft 42 in the gear position, that is, the first synchronizer S1 is engaged with the first drive gear Gd or the second drive gear Ge, which can realize the pure electric EV mode.

[0062] 3. The first clutch C1 is disengaged, the second clutch C2 is locked, and the first motor 21 and the second motor 22 are connected to the sun gear shaft 34 and the sun gear 33 through the second clutch C2; only the gear on the first input shaft 41 is engaged, that is, one of the synchronizers on the first input shaft 41 engages with one of the drive gears on the first input shaft 41 or directly engages with the output gear Gm, and the engine 1 performs differential drive with the first motor 21 and the second motor 22.

[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 engaged respectively, and the engine 1 and the first motor 21 and the second motor 22 can achieve split shaft drive, that is, the engine 1 can drive the vehicle simultaneously through the first input shaft 41 and the motor through the second input shaft 42.

[0064] 5. With the first clutch C1 locked and the second clutch C2 locked, the engine 1 is locked to the first motor 21, the second motor 22, the first input shaft 41, and the second input shaft 42. When the first input shaft 41 is engaged, the engine 1, the first motor 21, and the second motor 22 coaxially drive the gear on the first input shaft 41. When the second input shaft 42 is engaged, the engine 1, the first motor 21, and the second motor 22 coaxially drive the gear on the second input shaft 42.

[0065] The various operating conditions in this embodiment are further explained below:

[0066] I. Idle Start-Stop:

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

[0068] II. Idle power generation:

[0069] When engine 1 is running, the first clutch C1 disengages, and the second clutch C2 locks. Engine 1 is connected to the first motor 21 and the second motor 22 via planetary gear mechanism 3. The first synchronizer S1 of gearbox 4 is in the neutral position, and the third synchronizer S3 is engaged on the left side, which is in first gear with the fifth drive gear Gh. In this way, engine 1 can drive the first motor 21 and the second motor 22 to generate electricity, which charges the drive battery and powers the electric air conditioner.

[0070] III. Pure Electric Drive Condition (EV):

[0071] The second clutch C2 disengages, and the first synchronizer S1 engages with the first driving gear Gd on the left or with the second driving gear Ge on the right. Then, it engages with the output gear Gm through the seventh driven gear G7, allowing the first motor 21 and the second motor 22 to output power. The first motor 21 and the second motor 22 can also drive the vehicle in reverse. Alternatively, the first motor 21 and the second motor 22 can also achieve regenerative braking, requiring only that the first motor 21 and the second motor 22 output torque in the opposite direction of rotation.

[0072] IV. Hybrid Drive Conditions (HEV):

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

[0074] 1) Hybrid coaxial drive operation (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: First clutch C1 is locked, second clutch C2 is locked, third synchronizer S3 engages the left side with the fifth drive gear Gh, and then through the first driven gear G1, the seventh driven gear G7 and the output gear Gm, the engine 1 drives the vehicle forward by connecting the first input shaft 41 and the corresponding gear set through the first clutch C1 and the planetary gear mechanism 3. The first motor 21 and the second motor 22 drive the vehicle forward by connecting the first input shaft 41 and the corresponding gear set through the second clutch C2 and the planetary gear mechanism 3.

[0077] Third, fourth, sixth, and seventh gears: Similar to the first gear mentioned above, the clutches C1 and C2 are in the same open / closed state, and are engaged in the corresponding gears by the corresponding synchronizers. The engine 1 drives the vehicle forward by connecting the first input shaft 41 to the corresponding gear set through the first clutch C1 and the planetary gear mechanism 3. The first motor 21 and the second motor 22 drive the vehicle forward by connecting the first input shaft 41 to the corresponding gear set through the second clutch C2 and the planetary gear mechanism 3.

[0078] Hybrid coaxial drive second input shaft 42:

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

[0080] Fifth gear: First clutch C1 is locked, second clutch C2 is locked, first synchronizer S1 engages with the right side and second drive gear Ge, and then through the fifth driven gear G5, the seventh driven gear G7 and the output gear Gm, engine 1 drives the vehicle forward by connecting 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. First motor 21 and second motor 22 drive the vehicle forward by connecting the second input shaft 42 and the corresponding gear set.

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

[0082] Low-speed operation:

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

[0084] 2. Split-shaft drive in second and third gears: Similar to the two low-speed operating conditions mentioned above, the clutch engagement and disengagement are the same. The corresponding synchronizer engages the corresponding gear, and the engine 1, the first motor 21, and the second motor 22 drive the vehicle forward through the corresponding mechanism.

[0085] High-speed operating conditions:

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

[0087] The split shaft drives the fourth gear, the second synchronizer S2 engages with the left side and the third drive gear Gf, 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 corresponding gear set of the fourth gear.

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

[0089] The split-shaft drive is in six gears. The fourth synchronizer S4 engages with the left side and the seventh drive gear Gj. The engine 1 drives the vehicle forward through the first clutch C1, the planetary gear mechanism 3, the first input shaft 41 and the corresponding gear set of the sixth gear.

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

[0091] The split-shaft drive is in seventh gear, and the fourth synchronizer S4 engages with the right side and the output gear Gm. 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 setup: First clutch C1 is disengaged, second clutch C2 is locked, and first input shaft 41 is engaged.

[0094] Operating condition 1, starting engine 1 after stopping: First synchronizer S1, second synchronizer S2, third synchronizer S3, and fourth synchronizer S4 are all in the neutral position and in neutral. First motor 21 and second motor 22 reverse, driving engine 1 to rotate forward and start.

[0095] Operating condition 2, parking and power generation: engage P gear (or apply the brake) and first input shaft 41 in first gear (third synchronizer S3 engages with the left side and fifth drive gear Gh to engage 1st gear, first synchronizer S1 is in neutral). Engine 1 rotates forward and outputs power, while first motor 21 and second motor 22 rotate in reverse to absorb power and generate electricity.

[0096] Condition 3, Engine 1 drives the start: Engage the first input shaft 41, release the brake pedal, the engine 1 increases torque, the increased torque accelerates in the positive direction, and drives the vehicle to speed up through the first input shaft 41; at the same time, the first motor 21 and the second motor 22 increase torque and accelerate in the positive direction, and drive the vehicle to speed up 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. The power of engine 1 is transmitted to the ring gear 31 of planetary gear mechanism 3 through the output shaft of engine 1. The first motor 21 and the second motor 22 are transmitted to the sun gear 33 through the second clutch C2. The planetary carrier 36 drives the wheels through the first input shaft 41 and the corresponding gear set. When the vehicle is stationary, the planetary carrier 36 is in a fixed state. Engine 1 transmits power to the first motor 21 and the second motor 22 through planetary gear mechanism 3, thereby driving the first motor 21 and the second motor 22 to rotate and generate electricity. When the vehicle needs to start, controlling the speed of the first motor 21 and the second motor 22 controls the speed of planetary carrier 36, thereby outputting the power of engine 1 to gearbox 4 to drive the vehicle. Planetary gear mechanism 3 can also increase the output torque of engine 1 according to the speed ratio. When the speed of the first motor 21 and the second motor 22 is close to the speed of engine 1, the first clutch C1 is locked and the second clutch C2 is disengaged. At this time, planetary gear mechanism 3 is in a locked state, and the power of engine 1 directly drives the vehicle.

[0098] In this embodiment, when a heavy vehicle starts, the first clutch C1 disengages and the second clutch C2 locks. The engine 1 and the motor 2 (including the first motor 21 and the second motor 22) drive the vehicle differentially through the planetary gear mechanism 3. This mode overcomes the problem that when a heavy vehicle starts, it requires a starting clutch, but the clutch is in a semi-engaged state, relying on the friction of the clutch plates to transmit power, which causes the engine torque to be not fully transmitted, making starting difficult.

[0099] V. (HEV) Uninterrupted Gear Shifting Process:

[0100] 1. In HEV mode, when switching from coaxial drive first gear (first clutch C1 and second clutch C2 locked, third synchronizer S3 engaged on the left and connected to the fifth drive gear Gh) to split-shaft drive first and second gears: the motor is unloaded, engine 1 increases torque, second clutch C2 disengages, first motor 21 and second motor 22 are synchronized, first synchronizer S1 engages on the left and connected to the first drive gear Gd, and first motor 21 and second motor 22 restore torque. Engine 1 torque is output through first clutch C1, planetary gear mechanism 3, first input shaft 41, and first gear set. First motor 21 and second motor 22 torque is output through second input shaft 42 and second gear set.

[0101] 2. Switching from split-shaft drive first and second gears to coaxial drive second gear: Engine 1 is unloaded, the first motor 21 and the second motor 22 increase torque, the third synchronizer S3 is engaged in the neutral position and disengaged from the fifth drive gear Gh, the second clutch C2 is locked, and engine 1 resumes torque. The torque of engine 1 is output through planetary gear mechanism 3, first clutch C1, second clutch C2, second input shaft 42, and second gear set. The torque of the first motor 21 and the second motor 22 is output through the second input shaft 42 and second gear set.

[0102] 3. Coaxial drive second gear switching to split-shaft drive third gear and second gear: Engine 1 is unloaded, first motor 21 and second motor 22 increase torque, first clutch C1 and second clutch C2 disengage, third synchronizer S3 engages on the right side with the sixth drive gear Gi, then first clutch C1 locks, and engine 1 resumes torque. Engine 1 torque is output through first clutch C1, planetary gear mechanism 3, first input shaft 41, and third gear set. First motor 21 and second motor 22 torque is output through second input shaft 42 and second gear set.

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

[0104] 5. Switching from split-shaft drive fourth and second gears to split-shaft drive fourth and fifth gears: First motor 21 and second motor 22 are unloaded, engine 1 increases torque, first synchronizer S1 is in the neutral position, first motor 21 and second motor 22 are synchronized, first synchronizer S1 engages its right side with the second drive gear Ge, and first motor 21 and second motor 22 restore torque. Engine 1 torque is output through first clutch C1, planetary gear mechanism 3, first input shaft 41, and fourth gear set. First motor 21 and second motor 22 torque is output through second input shaft 42 and fifth gear set.

[0105] 6. Switching from fourth and fifth gears in the split-shaft drive to fifth and sixth gears: Engine 1 is unloaded, the first motor 21 and the second motor 22 increase torque, the first clutch C1 disengages, the second synchronizer S2 is in the neutral position and disengaged from the third drive gear Gf, the fourth synchronizer S4 engages on the left side and engages with the seventh drive gear Gj, the first clutch C1 locks, and engine 1 resumes torque. The torque of engine 1 is output through the first clutch C1, planetary gear mechanism 3, first input shaft 41, and the sixth gear set. The torque of the first motor 21 and the second motor 22 is output through the second input shaft 42 and the fifth gear set.

[0106] 7. Switching from split-shaft drive fifth and sixth gears to split-shaft drive fifth and seventh gears: Engine 1 is unloaded, the first motor 21 and the second motor 22 increase torque, the first clutch C1 disengages, the fourth synchronizer S4 engages and disengages with the seventh drive gear Gj in the neutral position, then the fourth synchronizer S4 engages with the output gear Gm in the right position, the first clutch C1 locks, and engine 1 resumes torque. Engine 1 torque is output through the first clutch C1, planetary gear mechanism 3, first input shaft 41, and output gear Gm. The torque of the first motor 21 and the second motor 22 is output through the second input shaft 42 and the fifth gear set.

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

[0108] VI. Starting the vehicle using engine 1 when the drive battery is dead:

[0109] In extremely cold weather, the drive battery is restricted from working. Differential mode can be used to start the vehicle. The engine 1 increases torque to drive the first input shaft 41, which in turn 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 torque and accelerate in the positive direction, driving the vehicle to start through the first input shaft 41.

[0110] The following table can also be used as a reference for the various operating conditions in this embodiment:

[0111]

[0112] This system increases the total speed difference of the parallel shaft gear transmission, which eliminates the need for a secondary gearbox.

[0113] The working principle of this system is further explained as follows: When the system is 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 gear ring shaft 32, the motor 2 (in this embodiment, the motor 2 includes the first motor 21 and the second motor 22, but for the sake of convenience, only the motor 2 is used for description, and the same applies below) shaft 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 driven by differential speed.

[0114] For example, engine 1 has a torque of T.eng Motor 2 torque is T em =ρ·T eng The torque T acting on the first input shaft 41 C = (1+ρ)·T eng After passing through a first gear to reduce speed and increase torque, the output torque T out =(1+ρ)·η1·T eng The torque multiplier of engine 1 is (1+ρ)·η1. Due to the characteristics of the planetary gear mechanism 3, the speed ratio between 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 at T. C = (1+ρ)·T eng For ease of description, we'll say that the speed ratio of engine 1 at this point is (1+ρ)·η1. This speed ratio is (1+ρ) times larger than the first gear ratio η1, representing the maximum speed ratio of the system and the state when a heavy-duty vehicle starts. When the first clutch C1 is engaged, locking the planetary gear mechanism 3, engine 1 connects to the first input shaft 41 and rotates at the same speed; simultaneously, the gearbox engages the highest gear η7, and the speed ratio of engine 1 is η7. The total speed difference of the system is equal to the ratio of the maximum speed ratio to the minimum speed ratio; the total speed difference of this system is (1+ρ)·η1. max / η min = (1+ρ)·η1 / η7.

[0115] For parallel shaft gearboxes, the transmission gears must have a sufficient number of teeth to smoothly transmit torque; the transmission gears, especially the first gear drive gear, must have a sufficiently large module to transmit a certain amount of torque. Therefore, the gears need a sufficient number of teeth and a sufficiently large module, and their diameter cannot be too small. In addition, many other engineering factors (such as shaft diameter, gear bearings, and synchronizer arrangement) limit the minimum size of the gears. The center distance of a parallel shaft gearbox is a very important parameter, greatly affecting the transmitted torque, the weight of the gearbox, and its overall size. With a fixed center distance, the total gear ratio of the gearbox is limited by the minimum size of the gears.

[0116] In the prior art, due to the aforementioned limitations, the total step difference η of the AMT transmission is... max / η min The maximum value cannot exceed 12, which is insufficient to achieve the total gear ratio of 15 or more required for heavy-duty vehicle transmissions. Therefore, an auxiliary transmission is usually added. The input shaft of the auxiliary transmission is connected to the output shaft of the main transmission, amplifying the input torque several times. The torque value to be transmitted is very large, resulting in high cost of the shifting mechanism and susceptibility to failure.

[0117] In this system, using the same center distance, the total stage difference of a simple gearbox is equal to η. max / η minThis can achieve a value of 10 to 12. Multiplying this by the reduction and torque increase ratio of the planetary gear set, the equivalent total stage 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, this system extends the total gear ratio of engine 1 by 35% to 75%, reaching or exceeding the total gear ratio of 15 to 20 required by heavy vehicle transmissions. As a result, an auxiliary transmission is no longer needed, which simplifies the system, reduces costs, and lowers maintenance costs.

[0118] This system can stably output maximum torque at zero vehicle speed, and has strong vehicle traction and heavy-load hill-start capabilities.

[0119] For existing heavy-duty vehicles, when engine 1 drives the vehicle to start, the engine speed is above 1000 rpm; while the wheel speed starts from zero and increases with the vehicle speed; correspondingly, the speed of the transmission input shaft also starts from zero and gradually increases until it rotates at the same speed as the engine shaft, and then the engine shaft locks with the transmission input shaft, completing the starting process. When there is a speed difference between the two shafts and they cannot lock, the AMT transmission must rely on clutch slippage to transmit torque; the process of transmitting torque through slippage inevitably generates heat, and the amount of heat generated is proportional to the torque and time. Heavy-duty vehicles require high torque to start under heavy load, and the starting process lasts for a long time, generating a lot of heat. In particular, heavy-duty uphill starts require even higher torque and longer acceleration times, which can easily burn the friction material of the clutch. Some heavy-duty vehicles, such as mining trucks and dump trucks, are often stuck in potholes, gravel, etc., and high torque is required to get them out of trouble. Furthermore, clutch slip torque is determined by the pressure of the clutch friction plates, which is prone to fluctuations: excessive pressure may lock the clutch, causing a significant drop in engine speed or even engine stalling; insufficient pressure will not transmit enough torque, making it difficult to start and disengage the vehicle on heavy loads. Clutch torque control is challenging, resulting in high component costs and complex control software technology. In short, heavy-duty vehicles rely on clutch slip to transmit torque, clutch control technology is difficult, torque transmission is unstable, starting and disengaging on heavy loads is difficult, and clutch friction plates wear out rapidly, requiring frequent replacement and maintenance, increasing operating costs and reducing production efficiency.

[0120] This system employs a novel heavy-load starting method. The system is configured as follows: the first clutch C1 is disengaged, and the planetary gear mechanism 3 is in differential mode; clutch C2 is engaged, connecting the motor 2 shaft to the sun gear shaft 34; the first input shaft 41 is engaged in first gear, and the second input shaft 42 is not engaged. Thus, the engine 1 output shaft is connected as input to the ring gear shaft 32, the motor 2 shaft is connected as input to the sun gear shaft 34, and the planetary carrier shaft 37 is connected as output to the first input shaft 41, driving the wheels through the first gear.

[0121] The three shaft speeds of planetary gear mechanism 3 are subject to kinematic constraints: ρ·n S +n R =(1+ρ)·n C The torques of the three shafts of planetary gear mechanism 3 are related as follows: T S =ρ·T R And: T C =T S +T R .

[0122] At the moment of starting, the planetary carrier shaft rotates at 37 rpm. C The value is zero, and engine 1 is rotating forward at a speed of n. R The rotational speed of motor 2 shaft is -n R / ρ (reverse rotation); Engine 1 output torque is T R =T eng Motor 2 torque is T S =ρ·T R =ρ·T eng The planetary carrier shaft has a torque of 37 T. C =T S +T R =(1+ρ)T eng The torque is (1+ρ) times that of engine 1. After starting, the torque of planetary carrier shaft 37 drives the wheels to rotate through the first gear of first input shaft 41, thereby accelerating the vehicle. As the vehicle speed increases, the speed of first input shaft 41 and planetary carrier shaft 37 increases. At the same time, the speed of engine 1 remains unchanged, while motor 2 accelerates in the forward direction. When the speed of motor 2 (connected to sun gear shaft 34) and the speed of first input shaft 41 (connected to planetary carrier shaft 37) are equal to the speed of engine 1 (connected to ring gear shaft 32), the first clutch C1 is engaged and locked, the output shaft of engine 1 is connected to the input shaft of gearbox, and the starting process is completed.

[0123] During start-up, the engine delivers 1 T of torque. eng Motor 2 output ρ·T eng The torque of the first input shaft 41 is (1+ρ)T eng After passing through first gear to reduce speed and increase torque, the output torque is (1+ρ)·η1·T eng The deceleration torque multiplier is (1+ρ)·η1, which is equivalent to a speed ratio of (1+ρ)·η1. The driving force is very strong and stable. In particular, there is no phenomenon of generating a large amount of sliding heat or friction plate erosion throughout the entire process. The technically complex clutch torque control can be replaced by ordinary motor control, simplifying the control.

[0124] This system eliminates the starting clutch, completely solving the problem of clutch friction plate slippage and erosion.

[0125] Typically, AMT (Automated Manual Transmission) relies on clutch slippage to transmit torque and drive the vehicle to start. Heavy-duty vehicles have high clutch slippage torque and long operating times, generating significant amounts of slippage heat. This causes the clutch friction plates to continuously erode, requiring frequent maintenance or replacement. Some heavy trucks require friction plate replacement every two to three months, increasing operating costs and impacting work efficiency.

[0126] This system consists of an engine, an electric motor, and a planetary gear set, forming a differential drive starting mechanism. It utilizes the electric motor's ability to reverse positive torque and the planetary gear set's differential drive function to differentially drive heavy-duty vehicles to start. Therefore, this system eliminates the need for a starting clutch required by ordinary AMTs; it also avoids relying on clutch slippage to transfer torque, thus simplifying clutch control; and it eliminates the need for regular maintenance and friction plate replacement, reducing operating costs and improving production efficiency.

[0127] This system enables gear shifting without power interruption, solving the problem of heavy-duty vehicles having difficulty climbing hills.

[0128] Furthermore, when engine 1 shifts gears, motor 2 continues to drive and compensates for torque to maintain driving force, thus achieving uninterrupted gear shifting.

[0129] Heavy-duty vehicles, such as mining trucks, face difficulties shifting gears when climbing hills under heavy loads. Mining trucks frequently encounter situations where they need to start and climb uphill with heavy loads. Normally, the transmission starts in first gear (the starting gear), then shifts to second gear, then third gear, and so on, as speed increases. AMT (Automated Manual Transmission) shifting involves the following steps: 1. Reducing engine torque to zero (unloading), 2. Disengaging the clutch, 3. Disengaging the existing gear, 4. Shifting to the new gear, 5. Re-locking the clutch, and 6. Restoring engine torque. Shifting to the new gear takes the longest time. This process results in a power interruption, causing the heavy vehicle to lose driving force and decelerate due to the slope. Sometimes, with steep inclines and lengthy shifting processes, the heavy vehicle decelerates significantly, making it impossible to shift to the new gear and continue climbing. In other words, heavy-duty vehicles face difficulties shifting gears when climbing hills under heavy loads using AMT, and the lower the speed and the lower the gear, the more difficult the shifting becomes: shifting from first gear (the starting gear) to second gear (the first driving gear) is the most difficult. If a heavy vehicle reverses during gear shifting, it can easily lead to a safety accident, which must be strictly prevented. When a heavy vehicle is unable to shift gears while climbing a hill under heavy load, it is forced to climb in a very low gear, resulting in a very slow speed and a significant impact on production efficiency.

[0130] When this system is used for heavy-load uphill gear shifting, the engine 1 and the drive motor alternately drive and shift gears, achieving gear shifting without power interruption, avoiding slippage, and preventing safety accidents. The process is as follows:

[0131] a) Switching from "Starting State" to "First Drive Gear": When the vehicle starts, the gearbox is in first gear, and engine 1 and motor 2 are driven differentially through planetary gear mechanism 3. The torque amplification factor of engine 1 is (1+ρ)·η1, which can be understood as the speed ratio of engine 1 being (1+ρ)·η1. This is the starting state of this system (corresponding to the first gear of an AMT). As the vehicle speed increases, when the speed of motor 2 is approximately equal to the speed of engine 1, the first clutch C1 locks, and engine 1 directly drives in first gear. The speed ratio of engine 1 is η1, which is the "first drive gear" of this system, i.e., first gear. After the first clutch C1 locks, engine 1 can drive in first gear alone; at the same time, clutch C2 disengages, engaging second gear, and motor 2 is driven through the second input shaft 42 and the second gear. This process of shifting from "starting state ((1+ρ)·η1)" to "first drive gear (η1)" is completely smooth, the starting driving force remains unchanged, and there is no issue of vehicle deceleration.

[0132] 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 the second gear; 2. Disengage first gear; 3. Engage the locking clutch C2, locking engine 1 and motor 2 together; 4. Engine 1 restores torque, driving through the second input shaft 42 and the second gear with a reduction ratio of η2, completing the upshifting process. The shifting process from the first drive gear η1 to the second drive gear η2 eliminates the need for manual shifting, significantly shortening the shifting time. Furthermore, motor 2 maintains drive, allowing heavy vehicles to shift smoothly without deceleration or even rolling backwards.

[0133] c) Shifting from second to third 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 the second gear; 2. Disengage the first clutch C1 and the second clutch C2; 3. Engage third gear η3; 4. Close and lock the first clutch C1, locking engine 1 and the first input shaft 41 together; 5. Engine 1 restores torque, driving through the second input shaft 42 and the second gear at a reduction ratio of η2, completing the upshifting process. The shifting process from the second drive gear η2 to the third drive gear η3 eliminates the disengagement step, shortening the shifting time; and with motor 2 maintaining drive, heavy vehicles can shift smoothly, achieving uninterrupted shifting without causing vehicle deceleration or even rolling backwards.

[0134] d) Shifting from third 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. Disengage the first clutch C1; 3. Disengage third gear η3; 4. Engage fourth gear η4; 5. Close and lock the first clutch C1, locking engine 1 and the first input shaft 41 together; 6. Engine 1 restores torque, driving through the first input shaft 41 and the fourth gear with a reduction ratio of η4, completing the upshift process. Throughout the shifting process, motor 2 continuously drives the wheels through the second input shaft 42 and the second gear. Heavy vehicles can shift smoothly without experiencing vehicle deceleration or even rolling backward. In fact, at this point, the vehicle speed is already high, and the gearbox is in a high gear, so the problem of difficult shifting no longer exists.

[0135] If the transmission continues to upshift, it will switch from "low-medium speed" to "medium-high speed," which is no longer considered heavy-load steep hill climbing, but the shifting process is still described as follows:

[0136] e) Shifting from fourth to fifth gear: When the system shifts into fourth gear and continues to accelerate, motor 2 needs to shift from second to fifth gear first: 1. Motor 2 unloads torque, while engine 1 compensates for torque and continues to drive; 2. Disengage second gear; 3. Engage fifth gear; 4. Motor 2 restores torque. When engine 1 needs to shift to fifth gear, the shifting steps are as follows: 1. Engine 1 unloads torque, while motor 2 compensates for torque, continuing to drive the vehicle through the fifth gear; 2. Disengage fourth gear; 3. Close and lock the second clutch C2, locking engine 1 and motor 2 together; 4. Engine 1 restores torque, driving through the second input shaft 42 and the fifth gear with a reduction ratio of η5, completing the upshifting process. The shifting process from fourth to fifth gear eliminates the need for manual shifting, significantly shortening the shifting time, and with motor 2 maintaining drive, heavy vehicles can shift smoothly, achieving shifting without power interruption.

[0137] f) Shifting from 5th to 6th 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 the 5th gear; 2. Disengage the first clutch C1 and the second clutch C2; 3. Engage 6th gear η3; 4. Close and lock the first clutch C1, locking engine 1 and the first input shaft 41 together; 5. Engine 1 restores torque, driving through the first input shaft 41 and the 6th gear with a reduction ratio of η6, completing the upshifting process. This eliminates the need for disengaging the gear, shortening the shifting time; and with motor 2 maintaining drive, heavy vehicles can shift smoothly, achieving shifting without power interruption.

[0138] g) Shifting from 6th to 7th 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 the 5th gear; 2. Disengage the first clutch C1; 3. Disengage 6th gear η6; 4. Engage 7th gear η7; 5. Close and lock the first clutch C1, locking engine 1 and the first input shaft 41 together; 6. Engine 1 restores torque, driving through the first input shaft 41 and the 7th gear with a reduction ratio of η7, completing the upshift process. Throughout the shifting process, motor 2 continuously drives the wheels through the second input shaft 42 and the 5th gear, allowing heavy vehicles to shift smoothly and achieving uninterrupted power shifting.

[0139] Example 2 Figure 2 As shown, a hybrid power system suitable for heavy-duty vehicles differs from Embodiment 1 in that: this embodiment further 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 integrated, and the central axes of the reduction mechanism input shaft 51 and the reduction mechanism output shaft 52 are arranged to overlap.

[0140] The reduction mechanism 5 also includes two drive shafts 53, both of which are parallel to the output shaft 52 of the reduction mechanism. A fourth gear 54 is fixedly connected to the input shaft 51 of the reduction mechanism, and a fifth gear 55 is fixedly connected to the output shaft 52 of the reduction mechanism. A sixth gear 56 and a seventh gear 57 are fixedly connected to each drive shaft 53. The sixth gear 56 meshes with the fourth gear 54, and the seventh gear 57 meshes with the fifth gear 55.

[0141] The various working conditions and working principles of this embodiment are the same as those of Embodiment 1, except that after the speed reduction mechanism 5 reduces the speed, the output torque of the output shaft 52 of the speed reduction mechanism increases.

[0142] Example 3 Figure 3 As shown, a hybrid power system suitable for heavy-duty vehicles differs from Embodiment 1 in that: this embodiment further 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 integrated, and the central axes of the reduction mechanism input shaft 51 and the reduction mechanism output shaft 52 are arranged to overlap.

[0143] The reduction mechanism 5 also includes a second gear ring 5a, a second sun gear 5b, and three second planet gears 5c. Each second planet gear 5c meshes with both the second gear ring 5a and the second sun gear 5b. The three second planet gears 5c are connected to the second planet carrier 5d. The second planet carrier 5d is fixed to the output shaft 52 of the reduction mechanism. The second gear ring 5a is fixed to the housing of the reduction mechanism 5. The second sun gear 5b is fixed to the input shaft 51 of the reduction mechanism.

[0144] The various working conditions and working principles of this embodiment are the same as those of Embodiment 1, except that after the speed reduction mechanism 5 reduces the speed, the output torque of the output shaft 52 of the speed reduction mechanism increases.

[0145] Example 4 Figure 4 As shown, a hybrid power system suitable for heavy-duty vehicles differs from Embodiment 1 in that: the output shaft of engine 1 is connected to planetary carrier shaft 37, the second input shaft 42 is connected to sun gear shaft 34 through second clutch C2, the gear ring shaft 32 is connected to the first output shaft 41 and rotates simultaneously, the gear ring shaft 32 and the gear ring 31 are fixedly connected as one unit, and the first clutch C1 is located between the gear ring 31 (gear ring shaft 32) and the sun gear shaft 34.

[0146] This embodiment can achieve similar technical effects to Embodiment 1.

[0147] Example 5 Figure 5 As shown, a hybrid power system suitable for heavy-duty vehicles differs from Embodiment 1 in that: the output shaft of engine 1 is connected to the sun gear shaft 34, and the second input shaft 42 is connected to the gear ring 31 (gear ring shaft 32) through the second clutch C2. In this embodiment, the gear ring shaft 32 and the gear ring 31 are integrated, with the gear ring shaft 32 replaced by the gear ring 31. The planetary carrier shaft 37 is connected to the first input shaft 41 and can rotate simultaneously. The first clutch C1 is located between the gear ring 31 (gear ring shaft 32) and the sun gear shaft 34.

[0148] This embodiment can achieve similar technical effects to Embodiment 1.

[0149] Although the present invention has been specifically shown and described in conjunction with preferred embodiments, those skilled in the art should understand that various changes in form and detail may be made to the present invention without departing from the spirit and scope of the present invention as defined in the appended claims, and all such changes shall be within the scope of protection of the present invention.

Claims

1. A hybrid power system suitable for heavy-duty vehicles, comprising an engine and an electric motor, characterized in that: It also 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, and 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 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. The first clutch is located between any two shafts of the planetary gear mechanism; Synchronizers and drive gears are installed on both the first and second input shafts. Multiple driven gears are fixedly connected to the intermediate shaft. At least one reverse gear is also installed on the gearbox. An output gear is fixedly connected to the output shaft of the gearbox. The reverse gear meshes simultaneously with a driven gear on the intermediate shaft and a driving gear on the first input shaft. The output gear meshes with one of the driven gears on the intermediate shaft. Except for one driving gear meshing with the reverse gear, each of the driving gears on the first input shaft meshes with a driven gear on the intermediate shaft. The remaining driven gears on the intermediate shaft mesh with driving gears on the second input shaft. Combined with the position switching of multiple synchronizers, the gearbox can form neutral, reverse gear, and multiple forward gears. When a heavy vehicle starts, the first clutch disengages and the second clutch locks, and the engine and motor drive the vehicle differentially through a planetary gear mechanism.

2. A hybrid power system suitable for heavy-duty vehicles according to claim 1, characterized in that: The planetary gear mechanism includes three shafts: 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. A first clutch is disposed 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 suitable for heavy-duty 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 located between the sun gear shaft and the ring gear shaft. Alternatively, the engine output shaft is connected to the planetary carrier shaft, the second input shaft is connected to the sun gear shaft via the second clutch, the gear ring shaft is connected to the first output shaft and can rotate simultaneously, and the first clutch is located between the gear ring shaft and the sun gear shaft; Alternatively, the engine output shaft is connected to the sun gear shaft, the second input shaft is connected to the ring gear shaft via the second clutch, and the planetary carrier shaft is connected to the first input shaft and can rotate simultaneously; the first clutch is located between the ring gear shaft and the sun gear shaft.

4. A hybrid power system suitable for heavy-duty vehicles according to claim 1, characterized in that: The motor shaft is connected to the second input shaft via a reduction gear assembly.

5. A hybrid power system suitable for heavy-duty vehicles according to claim 4, characterized in that: There are two motors, namely the first motor and the 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 fixed to the first motor shaft and a third gear fixed to the second input shaft. The first gear and the third gear mesh with each other. The second motor shaft is connected to the second input shaft via a second reduction assembly. The second reduction assembly includes a second gear fixed to the second motor shaft and a third gear fixed to the second input shaft. The second gear and the third gear mesh with each other.

6. A hybrid power system suitable for heavy-duty vehicles according to claim 1, characterized in that: There are two intermediate shafts, each with multiple driven gears fixedly connected to it; the two intermediate shafts are symmetrically arranged relative to the first input shaft.

7. A hybrid power system suitable for heavy-duty vehicles according to claim 1, characterized in that: The second input shaft has two drive gears, namely the first drive gear and the second drive gear. The first drive gear meshes with a driven gear fixed to the intermediate shaft, and the second drive gear meshes with another driven gear fixed to the intermediate shaft. The synchronizer on the second input shaft can engage with the first drive gear or the second drive gear, or it can not engage with either the first drive gear or the second drive gear.

8. A hybrid power system suitable for heavy-duty vehicles according to claim 1, characterized in that: The first input shaft is equipped with three synchronizers. One of the synchronizers can engage with one of the drive gears on the first input shaft, or with the output gear, or not engage with either the drive gear or the output gear on the first input shaft. The other synchronizers on the first input shaft can engage with the drive gears on the first input shaft located on either side of them, or not engage with either of them.

9. A hybrid power system suitable for heavy-duty vehicles according to any one of claims 1 to 8, characterized in that: It also includes a speed reduction mechanism, which includes a speed reduction mechanism input shaft and a speed reduction mechanism output shaft, with the speed reduction mechanism input shaft connected to the gearbox output shaft.

10. A hybrid power system suitable for heavy-duty vehicles according to claim 9, characterized in that: The input shaft of the reduction mechanism is integrated with the output shaft of the gearbox. The central axes of the input shaft and the output shaft of the reduction mechanism overlap. The reduction mechanism also includes two transmission shafts. A fourth gear is fixedly connected to the input shaft of the reduction mechanism, and a fifth gear is fixedly connected to the output shaft of the reduction mechanism. 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 suitable for heavy-duty vehicles according to claim 9, characterized in that: The reduction mechanism also includes a second ring gear, a second sun gear, and multiple second planet gears. Each second planet gear meshes with both the second ring gear and the second sun gear. The multiple second planet gears are connected to a second planet carrier. The second planet carrier is fixed to the output shaft of the reduction mechanism. The second ring gear is fixed to the housing of the reduction mechanism. The second sun gear is fixed to the input shaft of the reduction mechanism. The input shaft of the reduction mechanism is integrated with the output shaft of the gearbox. The central axes of the input shaft and the output shaft of the reduction mechanism overlap.

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