Transmission and vehicle

Abstract

The application provides a kind of transmission and vehicle, it is related to vehicle engineering technical field.The transmission is constituted by front sub-gearbox assembly, main gearbox assembly and rear sub-gearbox assembly: front sub-gearbox adopts double input shaft structure, it is favorable to realize working condition adaptive load distribution;Main gearbox and rear sub-gearbox are collaboratively built multidimensional speed ratio matrix, significantly widen total speed ratio range and speed ratio span under the premise of not increasing gear number;Three box function decoupling: front sub-gearbox is responsible for power adaptation, main gearbox bears core gear shifting, rear sub-gearbox executes final ratio adjustment.Each box body integrated modular design, respectively optimize support lubrication system, axial force balance mechanism and electro-hydraulic actuator.The whole machine realizes the unity of high power density, wide speed ratio adaptability (covering start traction to overspeed cruising) and high gear shifting smoothness in compact space.

Description

Technical Field

[0001] This invention relates to the field of vehicle engineering technology, and in particular to a transmission and a vehicle. Background Technology

[0002] As heavy-duty commercial vehicles develop towards higher power density, wider speed ratio adaptability, and intelligent shifting, multi-speed automatic transmissions (AMTs) are facing the dual challenges of structural complexity and system reliability. Currently, mainstream heavy-duty AMTs generally adopt a main gearbox and a single-stage auxiliary gearbox architecture. The front auxiliary gearbox is mostly a planetary gear or fixed-axis structure driven by a single motor, providing only a single input path. Although this design can achieve basic speed ratio expansion, it is difficult to simultaneously meet the high output torque required for heavy-load starting and the lightweight requirements for high-speed cruising. Especially when matched with high-horsepower diesel engines or electric drive systems, the front auxiliary gearbox is forced to increase in size and weight due to bearing the power of a single path, resulting in a significant increase in the overall weight of the machine.

[0003] In terms of lubrication systems, existing technologies typically physically isolate the oil circuits of the main gearbox and the auxiliary gearbox: the main gearbox uses splash lubrication or local pressure lubrication, while the auxiliary gearbox relies on passive oil baths or independent small-displacement oil pumps, and the oils of the two cannot be exchanged. This fragmented design leads to problems such as insufficient oil film thickness and delayed heat dissipation on the contact surfaces of high-speed rotating parts (such as intermediate shaft gears and synchronizer sleeves) in the auxiliary gearbox, which exacerbates wear and limits reliability under continuous high-load conditions; at the same time, the existing mature oil circuit resources of the main gearbox cannot be utilized in a coordinated manner, resulting in redundant design of the lubrication system and wasted energy.

[0004] Regarding the smoothness of gear transmission, most existing transmissions use spur gears or helical gears without axial force balancing. Although spur gears have zero axial force, they result in large meshing impacts and poor NVH performance. On the other hand, some designs using helical gears often neglect the systematic configuration of the helix angle direction, causing the axial forces on the input shaft, intermediate shaft, and output shaft to be unable to cancel each other out. This requires the addition of thrust bearings and thickened housings for support, further increasing weight and cost, and causing micro-deformation of the shaft system, affecting the gear profile accuracy and long-term meshing stability.

[0005] In the shift actuator, the main gearbox generally uses a composite structure of gear hub and shift engagement teeth: the hub is fixed on the shaft, and the engagement teeth move axially with the synchronizer sleeve to complete the meshing. This structure has a large number of components and a long assembly tolerance chain, which not only reduces the overall structural rigidity, but also makes it prone to failure modes such as engagement tooth breakage and hub spline wear under high-frequency shifting conditions, resulting in high maintenance costs and difficulty in fault location. In addition, the auxiliary gearbox mostly uses a meshing sleeve type shift, which has a speed difference impact during high and low gear switching, resulting in poor shifting smoothness and obvious clutch engagement vibration, affecting driving comfort and power interruption time control accuracy. Summary of the Invention

[0006] The purpose of this invention is to provide a transmission and vehicle that achieve comprehensive optimization of the overall size, maintenance cost and shift smoothness of the transmission under the requirements of high power density and wide speed ratio adaptability.

[0007] In a first aspect, the transmission provided by the present invention includes a front auxiliary gearbox assembly, a main gearbox assembly, and a rear auxiliary gearbox assembly arranged sequentially along the power transmission direction; The front auxiliary box assembly is equipped with two front auxiliary box input shafts; The main gearbox assembly includes: a main gearbox input shaft, a main gearbox output shaft, and a main gearbox shifting assembly. The main gearbox input shaft and the main gearbox output shaft are selectively connected by transmission through the main gearbox shifting assembly. The two front auxiliary gearbox input shafts are respectively connected to the main gearbox input shaft through their respective transmission paths. The rear auxiliary gearbox assembly includes: a rear auxiliary gearbox intermediate shaft, a rear auxiliary gearbox output shaft, and a rear auxiliary gearbox shifting device. The rear auxiliary gearbox intermediate shaft is drivenly connected to the main gearbox output shaft. The rear auxiliary gearbox shifting device is installed on the rear auxiliary gearbox output shaft, and the rear auxiliary gearbox shifting device is used to selectively connect the rear auxiliary gearbox intermediate shaft and the main gearbox output shaft to the rear auxiliary gearbox output shaft.

[0008] In conjunction with the first aspect, the present invention provides a first possible implementation of the first aspect, wherein the rear auxiliary box intermediate shaft includes a first rear auxiliary box intermediate shaft and a second rear auxiliary box intermediate shaft; The main gearbox output shaft is connected to a main gearbox output shaft gear, and the rear auxiliary gearbox output shaft is fitted with a rear auxiliary gearbox output shaft low gear. The rear auxiliary gearbox shifting device is located between the main gearbox output shaft gear and the rear auxiliary gearbox output shaft low gear, and can be selectively engaged or disengaged from either the main gearbox output shaft gear or the rear auxiliary gearbox output shaft low gear. Both the first and second rear auxiliary gearbox intermediate shafts are connected to a constant mesh gear and a low gear on the rear auxiliary gearbox intermediate shaft. The main gearbox output shaft gear meshes with the constant mesh gear on the rear auxiliary gearbox intermediate shaft, and the low gear on the rear auxiliary gearbox output shaft meshes with the low gear on the rear auxiliary gearbox intermediate shaft. One of the intermediate shafts of the first and second rear auxiliary gearboxes is connected to an oil pump, and the other is connected to a power take-off unit.

[0009] In conjunction with the first possible implementation of the first aspect, the present invention provides a second possible implementation of the first aspect, wherein the oil pump is in fluid communication with the transmission lubrication circuit.

[0010] In conjunction with the first aspect, the present invention provides a third possible implementation of the first aspect, wherein the rear auxiliary gearbox shifting device includes a rear auxiliary gearbox high / low gear synchronizer mounted on the output shaft of the rear auxiliary gearbox.

[0011] In conjunction with the first aspect, the present invention provides a fourth possible implementation of the first aspect, wherein the main gearbox shifting assembly includes: a main gearbox input shaft gear, a main gearbox intermediate shaft, a main gearbox intermediate shaft constant mesh gear, a main gearbox intermediate shaft third gear, a main gearbox output shaft third gear, and a third and fourth gear hub sleeve; The main gearbox input shaft gear is connected to the main gearbox input shaft, the main gearbox intermediate shaft constant mesh gear and the main gearbox intermediate shaft third gear are respectively connected to the main gearbox intermediate shaft, and the main gearbox output shaft third gear is sleeved on the main gearbox output shaft; The main gearbox input shaft and the main gearbox output shaft are coaxially arranged. The third and fourth gear hub sleeves are located between the main gearbox input shaft gear and the main gearbox output shaft third gear. The third and fourth gear hub sleeves are axially slidably fitted to the main gearbox output shaft and can be selectively engaged or disengaged from either the main gearbox input shaft gear or the main gearbox output shaft third gear.

[0012] In conjunction with the fourth possible implementation of the first aspect, the present invention provides a fifth possible implementation of the first aspect, wherein a rear bearing of the main input shaft is installed between the main input shaft and the main output shaft.

[0013] In conjunction with the fourth possible implementation of the first aspect, the present invention provides a sixth possible implementation of the first aspect, wherein the main gearbox shifting assembly further includes: a second gear on the main gearbox intermediate shaft, a first gear on the main gearbox intermediate shaft, a first gear on the main gearbox output shaft, a second gear on the main gearbox output shaft, and a first and second gear hub sleeve; The second gear and the first gear of the main gearbox intermediate shaft are respectively connected to the main gearbox intermediate shaft, and the first gear and the second gear of the main gearbox output shaft are respectively sleeved on the main gearbox output shaft; The first and second gear hub sleeves are located between the first gear and the second gear of the main gearbox output shaft, and the first and second gear hub sleeves slide axially on the main gearbox output shaft, and can selectively engage or disengage with one of the first gear and the second gear of the main gearbox output shaft.

[0014] In conjunction with the first aspect, the present invention provides a seventh possible implementation of the first aspect, wherein the two front auxiliary gearbox input shafts are respectively connected to front auxiliary gearbox input shaft gears, the main gearbox input shaft is connected to a main gearbox input shaft auxiliary gear, and the two front auxiliary gearbox input shaft gears respectively mesh with the main gearbox input shaft auxiliary gear.

[0015] In conjunction with the first aspect, the present invention provides an eighth possible implementation of the first aspect, wherein the front auxiliary box assembly, the main box assembly and the rear auxiliary box assembly are rigidly connected in sequence by a common support plate.

[0016] Secondly, the vehicle provided by the present invention is equipped with the transmission described in the first aspect.

[0017] The embodiments of this invention bring the following beneficial effects: By innovatively constructing a three-level tandem power architecture with dual input shafts in the front auxiliary gearbox, multi-path coupling in the main gearbox, and shifting output in the rear auxiliary gearbox, the system-level collaborative optimization capability is significantly improved. The front auxiliary gearbox is equipped with two independent input shafts, supporting differentiated power input (such as direct drive path of diesel engine and electric drive auxiliary path), enabling dynamic load allocation under different operating conditions: a high torque input path is activated during heavy-load start-up, and a lightweight and efficient path is switched during high-speed cruising, thereby avoiding the size and weight redundancy caused by the excessive structural reinforcement of traditional single-path front auxiliary gearboxes to accommodate all operating conditions; at the same time, the dual input shaft design provides a natural interface for the subsequent hybridization and multi-source powertrain, enhancing the platform's scalability and the foundation for the execution of intelligent shifting strategies.

[0018] The rear auxiliary gearbox employs a shifting logic where either the intermediate shaft or the main gearbox output shaft connects to the rear auxiliary gearbox output shaft. Combined with the independent transmission paths of the two front and auxiliary gearbox inputs within the main gearbox, this forms a multi-dimensional speed ratio combination matrix. This significantly expands the overall speed ratio range and span without increasing the number of gears, effectively alleviating the inherent contradiction between low-speed traction and high-speed economy in heavy commercial vehicles. Furthermore, this architecture decouples the functional boundaries of each gearbox—the front auxiliary gearbox focuses on power source adaptation, the main gearbox on core gear switching, and the rear auxiliary gearbox handles final ratio adjustment and load distribution. This allows for targeted optimization of the lubrication system, axial force balance, and shifting actuators according to functional modules (such as shared oil passage design, helix angle system configuration, and integrated sliding sleeve structure). This reduces overall machine weight, decreases maintenance frequency, and suppresses shifting shocks, ultimately achieving a harmonious balance between high power density, wide speed ratio adaptability, and high shifting smoothness.

[0019] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the specific embodiments or related technologies of the present invention, the drawings used in the description of the specific embodiments or related technologies will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of a transmission provided in an embodiment of the present invention.

[0022] Icons: 1- Front auxiliary gearbox input shaft; 2- Front bearing of front auxiliary gearbox input shaft; 3- Front auxiliary gearbox input shaft gear; 4- Rear bearing of front auxiliary gearbox input shaft; 5- Front bearing of main gearbox intermediate shaft; 6- Constant mesh gear of main gearbox intermediate shaft; 7- Main gearbox intermediate shaft; 8- Third gear of main gearbox intermediate shaft; 9- Second gear of main gearbox intermediate shaft; 10- Main gearbox output shaft; 11- First gear of main gearbox intermediate shaft; 12- Rear bearing of main gearbox intermediate shaft; 13- Front bearing of rear auxiliary gearbox intermediate shaft; 14- Constant mesh gear of rear auxiliary gearbox intermediate shaft; 15- First rear auxiliary gearbox intermediate shaft; 16- Low gear of rear auxiliary gearbox intermediate shaft; 17- Rear bearing of rear auxiliary gearbox intermediate shaft; 18- Rear auxiliary gearbox Output shaft; 19-Rear auxiliary gearbox output shaft bearing; 20-Second rear auxiliary gearbox intermediate shaft; 21-Rear auxiliary gearbox output shaft low gear; 22-Rear auxiliary gearbox high and low gear synchronizer; 23-Main gearbox output shaft gear; 24-Main gearbox output shaft bearing; 25-Main gearbox output shaft first gear; 26-First and second gear hub sleeve; 27-Main gearbox output shaft second gear; 28-Main gearbox output shaft third gear; 29-Third and fourth gear hub sleeve; 30-Main gearbox input shaft rear bearing; 31-Main gearbox input shaft gear; 32-Main gearbox input shaft front bearing; 33-Main gearbox input shaft auxiliary gear; 34-Main gearbox input shaft auxiliary bearing; 35-Main gearbox input shaft. Detailed Implementation

[0023] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used only to describe differences in name and should not be construed as indicating or implying relative importance. Physical quantities in formulas, unless otherwise specified, should be understood as basic quantities in the International System of Units (SI), or derived quantities derived from basic quantities through mathematical operations such as multiplication, division, differentiation, or integration.

[0025] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0026] like Figure 1 As shown, the transmission provided in this embodiment of the invention includes a front auxiliary gearbox assembly, a main gearbox assembly, and a rear auxiliary gearbox assembly arranged sequentially along the power transmission direction. The front auxiliary gearbox assembly has two front auxiliary gearbox input shafts 1. The main gearbox assembly includes a main gearbox input shaft 35, a main gearbox output shaft 10, and a main gearbox shifting assembly. The main gearbox input shaft 35 and the main gearbox output shaft 10 are selectively connected via the main gearbox shifting assembly. The two front auxiliary gearbox input shafts 1 are respectively connected to the main gearbox input shaft 35 via their respective transmission paths. The rear auxiliary gearbox assembly includes a rear auxiliary gearbox intermediate shaft, a rear auxiliary gearbox output shaft 18, and a rear auxiliary gearbox shifting device. The rear auxiliary gearbox intermediate shaft is connected to the main gearbox output shaft 10. The rear auxiliary gearbox shifting device is installed on the rear auxiliary gearbox output shaft 18, and the rear auxiliary gearbox shifting device is used to selectively connect the rear auxiliary gearbox intermediate shaft and the main gearbox output shaft 10 to the rear auxiliary gearbox output shaft 18.

[0027] The front auxiliary gearbox assembly is equipped with two front auxiliary gearbox input shafts 1, which are arranged in parallel and rotate independently, each receiving power from different power branches of the engine or electric drive assembly. The two front auxiliary gearbox input shafts 1 are connected to the same main gearbox input shaft 35 via independent transmission paths (such as gear pairs or coupling structures), enabling the main gearbox input shaft 35 to have dual-source power input capability. This dual-input shaft design breaks through the rigid dependence of the traditional single-input path on the load-bearing capacity of the front auxiliary gearbox: under heavy-load start-up conditions, the two front auxiliary gearbox input shafts 1 can collaboratively share the input torque, reducing single-shaft stress and gear contact pressure; under high-speed cruising conditions, one shaft can be selected to enter idling or low-load state, reducing oil churning losses and rotational inertia, thus balancing high torque load-bearing capacity and lightweight operation requirements without increasing structural size. In the main gearbox assembly, the main gearbox input shaft 35 and the main gearbox output shaft 10 are coaxially arranged, and multi-gear selective transmission is achieved through the main gearbox shifting component, forming the core of the main transmission. The rear auxiliary gearbox assembly uses the main gearbox output shaft 10 as the power source, and transmits power through the rear auxiliary gearbox intermediate shaft to the rear auxiliary gearbox output shaft 18, with high and low gear switching controlled by the rear auxiliary gearbox shifting device. This three-level architecture spatially decouples the speed ratio expansion task. The front auxiliary gearbox is responsible for input-side pre-allocation, the main gearbox undertakes the main transmission and fine-grained gear control, and the rear auxiliary gearbox realizes the final ratio switching on the output side. This avoids the structural bulkiness and rigidity degradation caused by a single gearbox bearing the entire speed ratio range, and provides a structural basis for the compact layout and optimized mass distribution of the whole machine.

[0028] The two front and auxiliary gearbox input shafts 1 split the input torque, reducing the mechanical load of a single path, allowing for a reduction in the gear module and bearing specifications of the front and auxiliary gearboxes, and reducing the weight and volume of the front and auxiliary gearboxes; the three-stage series structure decouples the power path in segments, and each gearbox can independently optimize the shell stiffness, bearing arrangement and heat dissipation structure according to the working conditions, which can improve the consistency of the overall structural stiffness and suppress the influence of shaft micro-deformation on gear meshing accuracy; the main gearbox input shaft 35 and the main gearbox output shaft 10 are coaxial, shortening the power flow span, reducing cantilever length and torsional deflection, and improving the alignment stability of the gears inside the main gearbox.

[0029] Furthermore, the intermediate shaft of the rear auxiliary gearbox includes a first intermediate shaft 15 and a second intermediate shaft 20; the main gearbox output shaft 10 is connected to a main gearbox output shaft gear 23, and a low-gear gear 21 is sleeved on the rear auxiliary gearbox output shaft 18; the rear auxiliary gearbox shifting device is located between the main gearbox output shaft gear 23 and the low-gear gear 21, and can be selectively engaged or disengaged from one of the main gearbox output shaft gear 23 and the low-gear gear 21; both the first intermediate shaft 15 and the second intermediate shaft 20 are connected to a constant mesh gear 14 and a low-gear gear 16, the main gearbox output shaft gear 23 meshes with the constant mesh gear 14, and the low-gear gear 21 meshes with the low-gear gear 16; one of the first intermediate shaft 15 and the second intermediate shaft 20 is connected to an oil pump, and the other is connected to a power take-off.

[0030] The first rear auxiliary gearbox intermediate shaft 15 connects to the oil pump, and the second rear auxiliary gearbox intermediate shaft 20 connects to the power take-off (PTO). This arrangement allows the oil pump and PTO to share the rear auxiliary gearbox intermediate shaft as their drive source, eliminating the need for an additional power branch or idler gear transmission chain. The oil pump is directly driven by the intermediate shaft, and its speed is strictly correlated with the main gearbox output shaft 10, ensuring a linear response of lubrication flow to the vehicle's operating conditions. The PTO also receives stable, low-pulsation power input, avoiding disturbances to the main drive system caused by independent PTO. Both the first and second rear auxiliary gearbox intermediate shafts 15 and 20 participate in power splitting, ensuring that the oil pump and PTO drive sources do not encroach on the main drive path, thus preventing the main gearbox output shaft 10 from bearing additional radial and axial loads. The oil pump and power take-off are located on different intermediate shafts to achieve functional isolation: the operation of the oil pump is not affected by the start and stop of the power take-off, and the lubrication system continues to supply oil when the power take-off is working; the constant meshing gear 14 of the intermediate shaft of the rear auxiliary gearbox and the gear 23 of the output shaft of the main gearbox form a constant meshing pair, so that the oil pump and the power take-off obtain a stable drive source with no impact and low vibration, and extend the service life of the auxiliary mechanism.

[0031] Furthermore, the oil pump is fluidly connected to the transmission lubrication circuit, with its suction port connected to the oil collection chamber at the bottom of the transmission and its discharge port connected to the main pressure oil passage shared by the main gearbox and the rear auxiliary gearbox. This main pressure oil passage is cast along the inside of the housing and has a ring-shaped branch structure, supplying oil to the main gearbox bearings, synchronizer actuator, rear auxiliary gearbox gear meshing area, and front and rear auxiliary gearbox bearings respectively. In particular, the bearing housings of the first rear auxiliary gearbox intermediate shaft 15 and the second rear auxiliary gearbox intermediate shaft 20 are provided with radial oil guide grooves, which are connected to the end of the main pressure oil passage, allowing the lubricating oil to be axially thrown into the gear meshing area under the centrifugal force of shaft rotation, forming an active oil film replenishment. This design changes the traditional lubrication mode of the auxiliary gearbox, which relies on passive oil baths or small-displacement independent oil pumps. It integrates the oil pump into the unified control of the main lubrication system, so that the lubrication supply of the high-speed rotating parts of the rear auxiliary gearbox (such as the constant mesh gear 14 of the intermediate shaft of the rear auxiliary gearbox, the low gear 16 of the intermediate shaft of the rear auxiliary gearbox, and the high and low gear synchronizer 22 of the rear auxiliary gearbox) is strongly coupled with the working conditions of the main gearbox: when the main gearbox is in a high-load position, the speed of the main gearbox output shaft 10 increases, the speed of the oil pump increases synchronously, and the flow and pressure of the lubricating oil automatically increase, thereby precisely matching the increased heat dissipation and oil film maintenance requirements of the gear pair of the rear auxiliary gearbox due to the increase in speed.

[0032] Furthermore, the rear auxiliary gearbox shifting device includes a rear auxiliary gearbox high / low gear synchronizer 22 mounted on the rear auxiliary gearbox output shaft 18. The gear hub of the rear auxiliary gearbox high / low gear synchronizer 22 is fixed to the rear auxiliary gearbox output shaft 18, and the sliding sleeve is axially slidable. Its two ends are respectively provided with engagement teeth that match the internal spline of the main gearbox output shaft gear 23, and engagement teeth that match the external spline of the low gear 21 of the rear auxiliary gearbox output shaft.

[0033] Furthermore, the main gearbox shifting assembly includes: a main gearbox input shaft gear 31, a main gearbox intermediate shaft 7, a main gearbox intermediate shaft constant mesh gear 6, a main gearbox intermediate shaft third gear 8, a main gearbox output shaft third gear 28, and a third and fourth gear hub sleeve 29; the main gearbox input shaft gear 31 is connected to the main gearbox input shaft 35, the main gearbox intermediate shaft constant mesh gear 6 and the main gearbox intermediate shaft third gear 8 are respectively connected to the main gearbox intermediate shaft 7, and the main gearbox output shaft third gear 28 is sleeved on the main gearbox output shaft 10; the main gearbox input shaft 35 and the main gearbox output shaft 10 are coaxially arranged, the third and fourth gear hub sleeve 29 is located between the main gearbox input shaft gear 31 and the main gearbox output shaft third gear 28, and the third and fourth gear hub sleeve 29 slides axially on the main gearbox output shaft 10, and can selectively engage or disengage with one of the main gearbox input shaft gear 31 and the main gearbox output shaft third gear 28.

[0034] The shifting action of the third and fourth gears occurs entirely on one side of the main gearbox output shaft 10. The main gearbox input shaft 35 and the main gearbox intermediate shaft 7 maintain rotational freedom throughout the entire process, without interrupting the input power flow for shifting. At the same time, the main gearbox input shaft gear 31 and the main gearbox output shaft third gear 28 are arranged face-to-face in the axial direction, which minimizes the axial travel of the third and fourth gear hub sleeve 29, reducing the power consumption and response delay of the shift fork drive.

[0035] Furthermore, a rear bearing 30 for the main gearbox input shaft 35 is installed between the main gearbox input shaft 35 and the main gearbox output shaft 10. This bearing is a double-row angular contact ball bearing, with its inner ring tightly fitted to the rear end of the main gearbox input shaft 35 and its outer ring tightly fitted to the corresponding bearing housing in the main gearbox housing. Its axial preload is set by adjusting shims to ensure that the main gearbox input shaft 35 can obtain stable support when subjected to bidirectional axial forces. This bearing not only bears the radial load of the main gearbox input shaft 35, but more importantly, it balances the axial force generated by the meshing of the main gearbox input shaft gear 31. Since the main gearbox input shaft gear 31 is a helical gear, its helix angle is designed to match the constant mesh gear 6 of the main gearbox intermediate shaft, so that the axial force of the two meshing gears is opposite in direction; and the rear bearing 30 of the main gearbox input shaft is located precisely on the line of action of the resultant force of this axial force, which can directly absorb the residual unbalance component, avoid the axial force from being transmitted to the front clutch or engine flywheel end, and reduce the risk of front seal leakage and abnormal bearing wear.

[0036] Furthermore, the main gearbox shifting assembly also includes: a second gear 9 on the main gearbox intermediate shaft, a first gear 11 on the main gearbox intermediate shaft, a first gear 25 on the main gearbox output shaft, a second gear 27 on the main gearbox output shaft, and a first and second gear hub sleeve 26; the second gear 9 and the first gear 11 on the main gearbox intermediate shaft are respectively connected to the main gearbox intermediate shaft 7, and the first gear 25 and the second gear 27 on the main gearbox output shaft are respectively sleeved on the main gearbox output shaft 10; the first and second gear hub sleeve 26 is located between the first gear 25 and the second gear 27 on the main gearbox output shaft, and the first and second gear hub sleeve 26 slides axially on the main gearbox output shaft 10, and can selectively engage or disengage with one of the first gear 25 and the second gear 27 on the main gearbox output shaft. All gear shifting is centralized on the main output shaft 10, and the unified actuator shaft simplifies the shift fork layout and the interface of the electronic actuator, reduces the accumulation of assembly tolerance chain of the shifting mechanism, and improves the repeatability of shifting positioning accuracy; the first and second gear hub sleeves 26 and the third and fourth gear hub sleeves 29 are axially separated to avoid interference of multiple sleeve movements, allowing the use of thicker tooth width sleeve structures, enhancing bending stiffness and tooth surface contact strength; the parameters of the empty sleeve gears are unified, reducing the types of gears and tool specifications, and reducing the complexity of supply chain management and spare parts inventory costs.

[0037] Two front auxiliary gearbox input shafts 1 are each connected to a front auxiliary gearbox input shaft gear 3, and the main gearbox input shaft 35 is connected to a main gearbox input shaft auxiliary gear 33. The two front auxiliary gearbox input shaft gears 3 mesh with the main gearbox input shaft auxiliary gear 33. The main gearbox input shaft auxiliary gear 33 is supported on the main gearbox housing by precision bearings, ensuring that the two meshing lines are strictly parallel. This allows the axial forces to cancel each other out when the torque transmitted from the two front auxiliary gearbox input shafts 1 is combined on the main gearbox input shaft 35. The mirrored configuration in the helix angle direction ensures that the leftward axial force generated by the left front auxiliary gearbox input shaft gear 3 and the rightward axial force generated by the right front auxiliary gearbox input shaft gear 3 are equally and oppositely canceled out at the main gearbox input shaft auxiliary gear 33. The main gearbox input shaft 35 as a whole only bears the net torque and radial force, requiring no additional axial positioning structure.

[0038] Furthermore, the front auxiliary gearbox assembly, main gearbox assembly, and rear auxiliary gearbox assembly are rigidly connected sequentially via a shared support plate. This support plate is a high-strength cast aluminum flat plate structure with a drive shaft through-hole in the center and evenly distributed bolt holes around its perimeter, which are bolted to the end flanges of the three gearboxes. The support plate is embedded with a network of reinforcing ribs, the direction of which ribs aligns with the main stress directions of each gearbox, ensuring that the relative positions of the three gearboxes remain constant and free from micron-level relative displacement when the entire machine is subjected to vehicle bumps, sudden torque changes, and braking drag loads. This integrated support structure replaces the traditional flexible connection method that relies on rubber bushings or flexible couplings between multiple gearboxes, making the three gearboxes a rigid whole in space. The coaxiality of the shaft system is guaranteed by the support plate in a single machining operation, rather than relying on individual machining of each gearbox followed by assembly and alignment.

[0039] Additionally, a front bearing 32 and a secondary bearing 34 are mounted on the main input shaft 35, with the secondary gear 33 located between them. A rear bearing 30 is mounted on the front section of the main input shaft 10, and a bearing 24 is connected to the rear section. A rear output shaft bearing 19 is mounted on the rear output shaft 18. The main input shaft 35, main output shaft 10, and rear output shaft 18 are coaxially arranged. Front and rear input shaft bearings 2 and 4 are mounted on both front and rear input shafts 1. A front and rear bearing 5 and a rear bearing 12 are mounted on both ends of the main intermediate shaft 7. A front and rear bearing 13 and a rear bearing 17 are mounted on both ends of the first and second rear intermediate shafts 15 and 20, respectively. All bearings rely on a high-strength cast aluminum common support plate to achieve a rigid connection of the three housings as a whole. The bearing seat holes are machined and formed by the support plate as a whole to ensure the coaxiality of the shaft systems of the front auxiliary housing, main housing, and rear auxiliary housing. This avoids the cumulative eccentricity and micro-deformation caused by traditional separate assembly, and significantly improves the smoothness of gear meshing and bearing life.

[0040] In this embodiment, the gear shifting process and the transmission route of each gear are as follows: First gear: The high and low gear synchronizer 22 of the rear auxiliary gearbox moves to the right, the first and second gear hub sleeve 26 moves to the right and engages the first gear 25 of the main gearbox output shaft. The front auxiliary gearbox input shaft 1, the front auxiliary gearbox input shaft gear 3, the main gearbox input shaft auxiliary gear 33, the main gearbox input shaft 35, the main gearbox input shaft gear 31, the main gearbox intermediate shaft constant mesh gear 6, the main gearbox intermediate shaft 7, the main gearbox intermediate shaft first gear 11, the main gearbox output shaft first gear 25, the main gearbox output shaft 10, the main gearbox output shaft gear 23, the rear auxiliary gearbox intermediate shaft constant mesh gear 14, the first rear auxiliary gearbox intermediate shaft 15 / the second rear auxiliary gearbox intermediate shaft 20, the rear auxiliary gearbox intermediate shaft low gear 16, the rear auxiliary gearbox output shaft low gear 21, and the rear auxiliary gearbox output shaft 18 are driven in sequence.

[0041] Second gear: The high and low gear synchronizer 22 of the rear auxiliary gearbox moves to the right, and the first and second gear hub sleeve 26 moves to the left to engage the second gear 27 of the main gearbox output shaft. The front auxiliary gearbox input shaft 1, the front auxiliary gearbox input shaft gear 3, the main gearbox input shaft auxiliary gear 33, the main gearbox input shaft 35, the main gearbox input shaft gear 31, the main gearbox intermediate shaft constant mesh gear 6, the main gearbox intermediate shaft 7, the main gearbox intermediate shaft second gear 9, the main gearbox output shaft second gear 27, the main gearbox output shaft 10, the main gearbox output shaft gear 23, the rear auxiliary gearbox intermediate shaft constant mesh gear 14, the first rear auxiliary gearbox intermediate shaft 15 / the second rear auxiliary gearbox intermediate shaft 20, the rear auxiliary gearbox intermediate shaft low gear 16, the rear auxiliary gearbox output shaft low gear 21, and the rear auxiliary gearbox output shaft 18 are driven in sequence.

[0042] Three gears: The high and low gear synchronizer 22 of the rear auxiliary gearbox moves to the right, the third and fourth gear hub sleeve 29 moves to the right and engages the third gear 28 of the main gearbox output shaft, and the front auxiliary gearbox input shaft 1, front auxiliary gearbox input shaft gear 3, main gearbox input shaft auxiliary gear 33, main gearbox input shaft 35, main gearbox input shaft gear 31, main gearbox intermediate shaft constant mesh gear 6, main gearbox intermediate shaft 7, main gearbox intermediate shaft third gear 8, main gearbox output shaft third gear 28, main gearbox output shaft 10, main gearbox output shaft gear 23, rear auxiliary gearbox intermediate shaft constant mesh gear 14, first rear auxiliary gearbox intermediate shaft 15 / second rear auxiliary gearbox intermediate shaft 20, rear auxiliary gearbox intermediate shaft low gear 16, rear auxiliary gearbox output shaft low gear 21, and rear auxiliary gearbox output shaft 18 are driven in sequence.

[0043] Fourth gear: The high and low gear synchronizer 22 of the rear auxiliary gearbox moves to the right, and the third and fourth gear hub sleeve 29 moves to the left to engage the main gearbox input shaft 35. The front auxiliary gearbox input shaft 1, the front auxiliary gearbox input shaft gear 3, the main gearbox input shaft auxiliary gear 33, the main gearbox input shaft 35, the main gearbox output shaft 10, the main gearbox output shaft gear 23, the constant mesh gear 14 of the rear auxiliary gearbox intermediate shaft, the first rear auxiliary gearbox intermediate shaft 15 / the second rear auxiliary gearbox intermediate shaft 20, the low gear 16 of the rear auxiliary gearbox intermediate shaft, the low gear 21 of the rear auxiliary gearbox output shaft, and the rear auxiliary gearbox output shaft 18 are driven in sequence.

[0044] Fifth gear: The rear auxiliary gearbox high and low gear synchronizer 22 moves to the left, the first and second gear hub sleeve 26 moves to the right to engage the first gear 25 of the main gearbox output shaft, and the front auxiliary gearbox input shaft 1, front auxiliary gearbox input shaft gear 3, main gearbox input shaft auxiliary gear 33, main gearbox input shaft 35, main gearbox input shaft gear 31, main gearbox intermediate shaft constant mesh gear 6, main gearbox intermediate shaft 7, main gearbox intermediate shaft first gear 11, main gearbox output shaft first gear 25, main gearbox output shaft 10, and rear auxiliary gearbox output shaft 18 are driven in sequence.

[0045] Sixth gear: The rear auxiliary gearbox high and low gear synchronizer 22 moves to the left, the first and second gear hub sleeve 26 moves to the left and engages the second gear 27 of the main gearbox output shaft, and the front auxiliary gearbox input shaft 1, the front auxiliary gearbox input shaft gear 3, the main gearbox input shaft auxiliary gear 33, the main gearbox input shaft 35, the main gearbox input shaft gear 31, the main gearbox intermediate shaft constant mesh gear 6, the main gearbox intermediate shaft 7, the main gearbox intermediate shaft second gear 9, the main gearbox output shaft second gear 27, the main gearbox output shaft 10, and the rear auxiliary gearbox output shaft 18 drive in sequence.

[0046] Seven gears: The rear auxiliary gearbox high and low gear synchronizer 22 moves to the left, the third and fourth gear hub sleeve 29 moves to the right and engages the main gearbox output shaft third gear 28, the front auxiliary gearbox input shaft 1, the front auxiliary gearbox input shaft gear 3, the main gearbox input shaft auxiliary gear 33, the main gearbox input shaft 35, the main gearbox input shaft gear 31, the main gearbox intermediate shaft constant mesh gear 6, the main gearbox intermediate shaft 7, the main gearbox intermediate shaft third gear 8, the main gearbox output shaft third gear 28, the main gearbox output shaft 10, and the rear auxiliary gearbox output shaft 18 drive in sequence.

[0047] Eight gears: The rear auxiliary gearbox high and low gear synchronizer 22 moves to the left, the third and fourth gear gear hub sleeve 29 moves to the left and engages the main gearbox input shaft 35, the front auxiliary gearbox input shaft 1, the front auxiliary gearbox input shaft gear 3, the main gearbox input shaft auxiliary gear 33, the main gearbox input shaft 35, the main gearbox output shaft 10, and the rear auxiliary gearbox output shaft 18 drive in sequence.

[0048] The vehicle provided in this embodiment of the invention is equipped with the transmission described in the above embodiments. The powertrain of the vehicle includes a diesel engine or an electric drive motor, which is connected to the input shaft 1 of the front auxiliary gearbox via a clutch or electronically controlled coupling device. The vehicle control unit (VCU) coordinates and controls the on / off switching of the dual input shafts of the front auxiliary gearbox, the movement of the sliding sleeves of each gear in the main gearbox, and the switching of the synchronizer in the rear auxiliary gearbox based on vehicle speed, throttle opening, gradient, and load signals, to achieve adaptive shifting under all working conditions. The dual input shaft on / off strategy is controlled by the VCU in a closed loop, realizing intelligent load distribution between heavy-load dual inputs and light-load single inputs. The shifting commands of the main gearbox and the rear auxiliary gearbox are coordinated according to the timing sequence of first synchronizing and then engaging, and first disengaging and then switching, to eliminate power interruption.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A transmission, characterized in that, It includes a front auxiliary box assembly, a main box assembly, and a rear auxiliary box assembly arranged sequentially along the power transmission direction; The front auxiliary box assembly is provided with two front auxiliary box input shafts (1); The main gearbox assembly includes: a main gearbox input shaft (35), a main gearbox output shaft (10), and a main gearbox shift assembly. The main gearbox input shaft (35) and the main gearbox output shaft (10) are selectively connected by transmission through the main gearbox shift assembly. The two front auxiliary gearbox input shafts (1) are respectively connected to the main gearbox input shaft (35) through their respective transmission paths. The rear auxiliary gearbox assembly includes: a rear auxiliary gearbox intermediate shaft, a rear auxiliary gearbox output shaft (18), and a rear auxiliary gearbox shifting device. The rear auxiliary gearbox intermediate shaft is connected to the main gearbox output shaft (10) for transmission. The rear auxiliary gearbox shifting device is installed on the rear auxiliary gearbox output shaft (18), and the rear auxiliary gearbox shifting device is used to selectively connect the rear auxiliary gearbox intermediate shaft and the main gearbox output shaft (10) to the rear auxiliary gearbox output shaft (18) for transmission.

2. The transmission according to claim 1, characterized in that, The rear auxiliary box intermediate shaft includes a first rear auxiliary box intermediate shaft (15) and a second rear auxiliary box intermediate shaft (20). The main output shaft (10) is connected to the main output shaft gear (23), and the rear auxiliary output shaft (18) is fitted with the rear auxiliary output shaft low gear (21). The rear auxiliary gearbox shifting device is located between the main gearbox output shaft gear (23) and the rear auxiliary gearbox output shaft low gear (21), and can be selectively engaged or disengaged from either the main gearbox output shaft gear (23) or the rear auxiliary gearbox output shaft low gear (21). The first and second rear auxiliary gearbox intermediate shafts (15 and 20) are both connected to a rear auxiliary gearbox intermediate shaft constant mesh gear (14) and a rear auxiliary gearbox intermediate shaft low gear (16). The main gearbox output shaft gear (23) meshes with the rear auxiliary gearbox intermediate shaft constant mesh gear (14), and the rear auxiliary gearbox output shaft low gear (21) meshes with the rear auxiliary gearbox intermediate shaft low gear (16). One of the first rear auxiliary gearbox intermediate shaft (15) and the second rear auxiliary gearbox intermediate shaft (20) is connected to an oil pump, and the other is connected to a power take-off unit.

3. The transmission according to claim 2, characterized in that, The oil pump is in fluid communication with the transmission lubrication oil circuit.

4. The transmission according to claim 1, characterized in that, The rear auxiliary gearbox shifting device includes a rear auxiliary gearbox high / low gear synchronizer (22) installed on the output shaft (18) of the rear auxiliary gearbox.

5. The transmission according to claim 1, characterized in that, The main gearbox shifting assembly includes: main gearbox input shaft gear (31), main gearbox intermediate shaft (7), main gearbox intermediate shaft constant mesh gear (6), main gearbox intermediate shaft third gear (8), main gearbox output shaft third gear (28), and third and fourth gear hub sleeve (29). The main gearbox input shaft gear (31) is connected to the main gearbox input shaft (35), the main gearbox intermediate shaft constant mesh gear (6) and the main gearbox intermediate shaft third gear (8) are respectively connected to the main gearbox intermediate shaft (7), and the main gearbox output shaft third gear (28) is sleeved on the main gearbox output shaft (10). The main gearbox input shaft (35) is coaxially arranged with the main gearbox output shaft (10). The third and fourth gear hub sleeve (29) is located between the main gearbox input shaft gear (31) and the main gearbox output shaft third gear (28). The third and fourth gear hub sleeve (29) slides axially with the main gearbox output shaft (10) and can be selectively engaged or disengaged from either the main gearbox input shaft gear (31) or the main gearbox output shaft third gear (28).

6. The transmission according to claim 5, characterized in that, A rear bearing (30) of the main input shaft is installed between the main input shaft (35) and the main output shaft (10).

7. The transmission according to claim 5, characterized in that, The main gearbox shifting assembly also includes: a second gear (9) on the main gearbox intermediate shaft, a first gear (11) on the main gearbox intermediate shaft, a first gear (25) on the main gearbox output shaft, a second gear (27) on the main gearbox output shaft, and a first and second gear hub sleeve (26). The second gear (9) of the main gearbox intermediate shaft and the first gear (11) of the main gearbox intermediate shaft are respectively connected to the main gearbox intermediate shaft (7), and the first gear (25) of the main gearbox output shaft and the second gear (27) of the main gearbox output shaft are respectively sleeved on the main gearbox output shaft (10). The first and second gear hub sleeve (26) is located between the first gear (25) and the second gear (27) of the main gearbox output shaft, and the first and second gear hub sleeve (26) slides axially on the main gearbox output shaft (10), and can be selectively engaged or disengaged from one of the first gear (25) and the second gear (27) of the main gearbox output shaft.

8. The transmission according to claim 1, characterized in that, The two front auxiliary gearbox input shafts (1) are respectively connected to the front auxiliary gearbox input shaft gears (3), and the main gearbox input shaft (35) is connected to the main gearbox input shaft auxiliary gear (33). The two front auxiliary gearbox input shaft gears (3) mesh with the main gearbox input shaft auxiliary gear (33) respectively.

9. The transmission according to claim 1, characterized in that, The front auxiliary box assembly, the main box assembly, and the rear auxiliary box assembly are rigidly connected in sequence via a common support plate.

10. A vehicle, characterized in that, The vehicle is equipped with a transmission as described in any one of claims 1 to 9.

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