Stepless speed change electric drive axle system and vehicle

Abstract

The invention relates to a stepless speed change electric drive axle system and a vehicle, and the system comprises a motor which is used for providing power; the first gear set is in transmission connection with the motor and distributes power; the input end of the stepless speed regulating mechanism is connected with the first gear set, and the stepless speed regulating mechanism is used for achieving stepless speed change; the planetary gear train comprises a sun gear, a planet gear, an inner gear ring and a planet carrier, the sun gear is in transmission connection with the first gear set, and the inner gear ring is in transmission connection with the output end of the stepless speed regulating mechanism; the differential mechanism is in transmission connection with the planet carrier and used for outputting power to wheels; the first gear set shunts power to the stepless speed regulating mechanism and the sun gear, and the two paths of power are coupled in the planetary gear train and then output to the differential mechanism through the planet carrier. The stepless speed regulating mechanism enables the rotating speed of the inner gear ring to be steplessly adjustable by adjusting the displacement and the rotating speed, so that stepless adjustment of the output rotating speed of the planet carrier is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle power systems, and particularly to a continuously variable transmission electric drive axle system and a vehicle. Background Art

[0002] At present, pure electric drive heavy commercial vehicles mainly adopt two drive modes, namely central electric drive and electric drive axle, to achieve vehicle power transmission. Among them, the electric drive axle shows greater development potential in practical applications due to its smaller installation space requirements and higher integration. Most of the common electric drive axles on the market adopt a stepped transmission structure with two to four gears, and adapt to different driving conditions by gear shifting.

[0003] However, this stepped transmission structure has obvious deficiencies: First, a limited number of gears are difficult to meet the requirements of complex and changeable working conditions, especially under frequent start-stop, climbing or heavy load conditions; Second, power interruption or shifting shock may occur during the gear shifting process, affecting the smooth operation of the vehicle; Third, the fixed transmission ratio makes the motor unable to always operate in the high-efficiency region, reducing the overall energy efficiency of the system.

[0004] In the prior art, some continuously variable transmission technologies for traditional internal combustion engine drives have also emerged, such as the hydro-mechanical continuously variable transmission applied to tractors. However, these technologies are mainly designed for the characteristics of internal combustion engines, with complex structures, difficult control, and are difficult to be directly applied to electric drive systems.

[0005] The working characteristics of the motor and the internal combustion engine are significantly different: The motor has a relatively wide high-efficiency range, but its efficiency will significantly decrease under ultra-low speed or ultra-high speed working conditions; At the same time, the maximum output torque characteristics of the motor at different speeds are also different from those of the internal combustion engine. Therefore, developing a dedicated continuously variable transmission technology for electric drive systems, enabling the motor to always operate in the high-efficiency region and at the same time meeting the power requirements of the vehicle under various working conditions, has important practical significance.

[0006] Therefore, there is an urgent need for a continuously variable transmission electric drive axle system with a simple structure, convenient control and high efficiency to meet the power requirements under different working conditions and at the same time keep the motor operating in the high-efficiency region. Summary of the Invention

[0007] The present invention discloses a continuously variable transmission electric drive axle system and a vehicle, aiming to solve the technical problems existing in the prior art.

[0008] The present invention adopts the following technical solutions:

[0009] On the one hand, an embodiment of the present invention provides a continuously variable transmission electric drive axle system, including:

[0010] - A motor for providing power.

[0011] - A first gear set, which is drivingly connected to the motor and distributes power;

[0012] - A stepless speed regulation mechanism, whose input end is connected to the first gear set and is used to achieve stepless speed change;

[0013] - A planetary gear train, including a sun gear, planetary gears, an internal gear ring and a planet carrier. The sun gear is drivingly connected to the first gear set, and the internal gear ring is drivingly connected to the output end of the stepless speed regulation mechanism;

[0014] - A differential, which is drivingly connected to the planet carrier and is used to output power to the wheels;

[0015] The first gear set diverts power to the stepless speed regulation mechanism and the sun gear. After the two-way power is coupled in the planetary gear train, it is output from the planet carrier to the differential; the stepless speed regulation mechanism adjusts the displacement and speed to make the speed of the internal gear ring steplessly adjustable, so as to realize the stepless adjustment of the output speed of the planet carrier.

[0016] As a preferred technical solution, the input shaft of the motor is drivingly connected to the first gear set through a constantly meshing gear;

[0017] The first gear set includes a first transmission gear and a second transmission gear that are coaxially fixed. The first transmission gear is drivingly connected to the stepless speed regulation mechanism, and the second transmission gear is drivingly connected to the sun gear.

[0018] As a preferred technical solution, the transmission ratios of the first transmission gear and the second transmission gear are different, so that the power transmitted to the stepless speed regulation mechanism and the sun gear is distributed according to a preset ratio to achieve the optimal power distribution efficiency.

[0019] As a preferred technical solution, the stepless speed regulation mechanism includes a first hydraulic variable unit and a second hydraulic variable that are connected to each other;

[0020] The input end of the first hydraulic variable unit is drivingly connected to the first transmission gear through a first connecting gear and is used to receive power input;

[0021] The output end of the second hydraulic variable unit is drivingly connected to the internal gear ring through a third connecting gear and is used to output the power after speed change adjustment to the internal gear ring.

[0022] As a preferred technical solution, both the first hydraulic variable unit and the second hydraulic variable unit include variable swash plate type hydraulic pump-motors, and the displacement and speed are changed by adjusting the swash plate angle;

[0023] The adjustment of the swash plate angle is comprehensively judged by the control system according to the vehicle driving state, load demand and / or motor efficiency, so that the motor can work in a high-efficiency range while meeting the vehicle power demand.

[0024] As a preferred technical solution, it further includes a locking mechanism which is connected to the internal gear ring and is used to lock the internal gear ring in a zero-speed state under preset conditions; when the locking mechanism works, the power is directly transmitted from the sun gear to the planet carrier.

[0025] As a preferred technical solution, it further includes a power take-off mechanism which is connected to the first gear set and is used to take a part of the power from the first gear set to drive vehicle auxiliary equipment.

[0026] As a preferred technical solution, it further includes a stepped speed regulation mechanism which is arranged between the differential and the planet carrier and is used to provide additional speed change gears on the basis of stepless speed change.

[0027] As a preferred technical solution, the stepped speed regulation mechanism includes a shift actuator, a shift sleeve and a second gear set. The second gear set includes a fourth connecting gear, a fifth connecting gear, a third transmission gear, a fourth transmission gear and a fifth transmission gear;

[0028] The fourth connecting gear and the fifth connecting gear are coaxially and fixedly connected to the planet carrier. The fourth connecting gear meshes with and drives the third transmission gear. The fifth connecting gear meshes with and drives the fourth transmission gear, and the transmission ratios of the fourth connecting gear and the fifth connecting gear are different;

[0029] The shift actuator is used to control the movement of the shift sleeve. The shift sleeve can be selectively connected to the third transmission gear or the fourth transmission gear for transmission;

[0030] The third transmission gear, the fourth transmission gear and the fifth transmission gear are coaxially and fixedly connected. The fifth transmission gear is connected to the differential for transmission.

[0031] On the other hand, the embodiment of the present invention further provides a vehicle, and the vehicle includes the stepless speed change electric drive axle system as described in any one of the above.

[0032] One embodiment of the above invention has the following advantages or beneficial effects:

[0033] The present invention mainly provides a stepless speed change electric drive axle system and a vehicle. Compared with the prior art, the stepless speed change electric drive axle system of the embodiment of the present invention adopts a power split structure, splits the motor power through the first gear set to the stepless speed regulation mechanism and the planetary gear train, and then couples and outputs the power from the planetary gear train to the differential, realizing high-efficiency power transmission. The stepless speed regulation mechanism makes the speed of the internal gear ring steplessly adjustable by adjusting the displacement of the hydraulic variable unit, can accurately control the output speed, meets the requirements of different working conditions of the vehicle, and at the same time keeps the motor working in a high-efficiency range, improving the energy utilization rate of the system.

[0034] In addition, the present invention can also be selectively configured with a locking mechanism, a power take-off mechanism, and a stepped speed regulation mechanism; among them, the locking mechanism can reduce the operating loss of the hydraulic system, the power take-off mechanism can extract part of the power to drive auxiliary equipment, and the stepped speed regulation mechanism provides additional speed change gears on the basis of stepless speed change, expanding the overall speed change range of the system. These structural designs provide the vehicle with higher adaptability and functional diversity, and are suitable for complex working conditions and extreme working environments. Brief Description of the Drawings

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for use in the description of the embodiments, which form a part of the present invention. The schematic embodiments of the present invention and their descriptions explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0036] Figure 1 Schematic structural diagram of the stepless speed change electric drive axle system provided in Embodiment 1 of the present invention;

[0037] Figure 2 Schematic structural diagram of the stepless speed change electric drive axle system provided in Embodiment 2 of the present invention.

[0038] Description of the reference numerals in the drawings:

[0039] Motor 11, input shaft 12, first transmission gear 21, second transmission gear 22, constantly meshing gear 23, first hydraulic variable unit 31, second hydraulic variable unit 32, first connecting gear 33, third connecting gear 34, planetary gear train 40, second connecting gear 41, sun gear 42, planetary gear 43, internal gear ring 44, planetary carrier 45, differential 51, wheel 61, fourth connecting gear 71, fifth connecting gear 72, third transmission gear 73, fourth transmission gear 74, fifth transmission gear 75, shift actuator 76, shift sleeve 77. Detailed Embodiments

[0040] To make the objectives, technical solutions, and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions of the present invention in combination with specific embodiments and corresponding drawings of the present invention. In the description of the present invention, it should be noted that the term "or" is generally used in the sense of including "and / or" unless otherwise clearly specified in the content.

[0041] In the description of the present application, the terms "first", "second", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0042] Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0043] Example 1

[0044] Currently, pure-electric drive commercial vehicles, especially engineering vehicles such as heavy commercial trucks, mining trucks, forklifts, and loaders, are gradually becoming an important development direction in the fields of transportation and construction machinery. Such vehicles usually have characteristics such as large load capacity, complex working conditions, and high requirements for power performance. The design of their drive systems needs to meet diverse working requirements and ensure the maximization of energy utilization efficiency. However, most of the common electric drive axles on the market currently adopt a stepped speed change structure from second gear to fourth gear, which is difficult to meet the requirements of complex and changeable working conditions, and the motor 11 cannot always operate in the high-efficiency range.

[0045] To solve the problems existing in the prior art, an embodiment of the present invention provides a continuously variable electric drive axle system, which includes a motor 11, a first gear set, a continuously variable speed regulating mechanism, a planetary gear train 40, and a differential 51. The power output by the motor 11 is split by the first gear set to the continuously variable speed regulating mechanism and the planetary gear train 40, and then coupled and output by the planetary gear train 40 to the differential 51 to achieve continuously variable speed regulation.

[0046] As Figure 1 , in a preferred embodiment, the motor 11 is arranged at the input end of the entire continuously variable electric drive axle system for inputting power to the system; the first gear set is in transmission connection with the motor 11 and distributes power; the input end of the continuously variable speed regulating mechanism is connected to the first gear set; the planetary gear train 40 includes a sun gear 42, planet gears 43, an internal gear ring 44, and a planet carrier 45. The sun gear 42 is in transmission connection with the first gear set, and the internal gear ring 44 is in transmission connection with the output end of the continuously variable speed regulating mechanism; the differential 51 is in transmission connection with the planet carrier 45 for outputting power to the wheels 61.

[0047] The first gear set splits the power to the continuously variable speed regulating mechanism and the sun gear 42. The two paths of power are coupled in the planetary gear train 40, and then output from the planet carrier 45 to the differential 51; the continuously variable speed regulating mechanism adjusts the displacement and speed to make the speed of the internal gear ring 44 continuously adjustable, so as to achieve continuously variable adjustment of the output speed of the planet carrier 45.

[0048] In a preferred embodiment, the motor 11 can be a permanent magnet synchronous motor or an induction motor, and the specific specifications or power ratings can be adaptively selected according to vehicle requirements and are not limited in this embodiment; the motor 11 is in transmission connection with the first gear set through its input shaft 12 to ensure the stability and reliability of power transmission.

[0049] In a preferred embodiment, the input shaft 12 of the motor 11 is coaxially and fixedly connected to the first gear set to achieve direct drive; in another preferred embodiment, in order to further adjust the transmission ratio between the motor 11 and the first gear set to provide greater flexibility, a driving gear is fixedly arranged on the input shaft 12 of the motor 11, and the driving gear is kept in meshing connection with the constantly meshing gear 23 on the first gear set, and power transmission is achieved through gear meshing.

[0050] It should be noted that although from the perspective of the motor 11 itself, the shaft connected to the first gear set is the output shaft of the motor 11, from the perspective of the entire continuously variable speed electric drive axle system, since this shaft is the shaft that inputs power to the system, and in order to distinguish it from the two output half shafts that output power to the wheels 61 at the end of the system, it is referred to as the input shaft 12 in this specification.

[0051] In a preferred embodiment, the first gear set includes a first transmission gear 21 and a second transmission gear 22 that are coaxially and fixedly connected, and both of them are coaxially and fixedly connected to the constantly meshing gear 23. Those skilled in the art should understand that the so-called coaxial fixed connection means that multiple gears share a common axis, and there is no possibility of relative rotation between multiple gears, and they rotate together.

[0052] In a preferred embodiment, the first transmission gear 21 is in transmission meshing with the first connecting gear 33, and the first connecting gear 33 is arranged at the input end of the continuously variable speed mechanism to achieve power transmission to the continuously variable speed mechanism; the second transmission gear 22 is in transmission meshing with the second connecting gear 41, and the second connecting gear 41 is arranged at the input end of the sun gear 42 to achieve power transmission to the sun gear 42 in the planetary gear train 40.

[0053] Optionally, the transmission ratios of the first transmission gear 21 and the second transmission gear 22 can be configured to be the same or different.

[0054] Preferably, the transmission ratios of the first transmission gear 21 and the second transmission gear 22 are configured to be different to achieve the optimal power distribution efficiency. Those skilled in the art understand that the transmission ratio refers to the diameter ratio or tooth number ratio of two meshing gears, which determines the relationship between the input and output speeds. Specifically, the transmission ratio of the first transmission gear 21 refers to the tooth number ratio or diameter ratio between the first transmission gear 21 and the first connecting gear 33, and the transmission ratio of the second transmission gear 22 refers to the tooth number ratio or diameter ratio between the second transmission gear 22 and the second connecting gear 41.

[0055] By configuring the transmission ratio of the first transmission gear 21 and the second transmission gear 22, the power transmitted to the stepless speed regulation mechanism and the sun gear 42 can be distributed according to a preset ratio. For example, according to the efficiency curve under common vehicle operating conditions, 60%-70% of the power can be transmitted to the stepless speed regulation mechanism, and 30%-40% of the power can be transmitted to the sun gear 42, thereby optimizing the overall efficiency of the system. Specifically, in this embodiment, the ratio of power distribution is not exemplified one by one, and those skilled in the art can make adaptive adjustments according to actual needs.

[0056] In a preferred embodiment, the stepless speed regulation mechanism includes a first hydraulic variable unit 31 and a second hydraulic variable unit 32 that are connected to each other. Among them, the first hydraulic variable unit 31 serves as the input end of the stepless speed regulation mechanism, and is in transmission connection with the first transmission gear 21 through the first connecting gear 33 for receiving power input. The second hydraulic variable unit 32 serves as the output end of the stepless speed regulation mechanism, and is in transmission connection with the gear on the internal gear ring 44 through the third connecting gear 34 for outputting the power after speed change adjustment to the internal gear ring 44.

[0057] In a preferred embodiment, both the first hydraulic variable unit 31 and the second hydraulic variable unit 32 include variable swash plate type hydraulic pump-motors. The two variable swash plate type hydraulic pump-motors are combined to form a hydrostatic transmission system. The first hydraulic variable unit 31 receives mechanical power input and converts it into hydraulic energy. The second hydraulic variable unit 32 converts the hydraulic energy back into mechanical power and outputs it to the internal gear ring 44 of the planetary gear train 40. The change of displacement and speed is achieved by adjusting the swash plate angle; preferably, the adjustment of the swash plate angle is comprehensively judged by the control system according to the vehicle driving state, load demand, and / or motor efficiency, so that the motor 11 can work in a high-efficiency range while meeting the vehicle power demand.

[0058] Specifically, the variable swash plate type hydraulic pump-motor realizes stepless speed change by adjusting the swash plate angle. It has a wide speed change range and faster response, and can be continuously adjusted within the transmission ratio range of -1 to +1, far exceeding the ability of a conventional mechanical transmission; in addition, the hydraulic system has better overload protection ability and smooth power transmission characteristics, can effectively absorb impact loads, and has a longer service life.

[0059] In actual operation, the controller will collect information such as vehicle speed, accelerator pedal position, slope, load, etc. in real time, and determine the optimal motor operating point under the current working conditions in combination with the preset motor 11 efficiency curve or mapping table. Then, by adjusting the swash plate angles of the first hydraulic variable unit 31 and the second hydraulic variable unit 32, the control system can accurately adjust the transmission ratio so that the motor 11 always works in a high-efficiency area. For example, in a low-speed and high-torque demand scenario, the system will increase the transmission ratio to provide sufficient torque; when cruising at high speed, the transmission ratio will be reduced to reduce the speed of the motor 11 and reduce energy loss. This control strategy based on multi-parameter optimization can significantly improve the efficiency of electric energy utilization and extend the pure electric range while meeting the vehicle's power requirements.

[0060] It should be noted that the embodiments of the present invention no longer specifically limit the specific specifications, models and technical parameters of the variable swash plate hydraulic pump-motor. Those skilled in the art can select hydraulic components of appropriate specifications according to factors such as actual application scenarios, vehicle tonnage, load characteristics, power requirements, etc., and adaptively design and select their displacement range, maximum working pressure, efficiency characteristics, etc. to meet the application requirements of different types of vehicles.

[0061] In a preferred embodiment, the planetary gear train 40 serves as the core power coupling device of the continuously variable electric drive axle system, and adopts a single-stage planetary gear structure, wherein the sun gear 42 is located at the center of the planetary gear train 40, and is connected to the second transmission gear 22 through the second connecting gear 41, and receives part of the power distributed from the first gear set; a plurality of planetary gears 43 are evenly distributed around the sun gear 42, and while meshing with the outer teeth of the sun gear 42, their outer circumferences are also meshed with the inner teeth of the inner gear ring 44, and the planetary gears 43 themselves can rotate around their axis and serve as the whole. The inner gear ring 44 surrounds the outer circumference of the entire planetary gear system 40, and its inner surface is processed with internal teeth. It is connected to the second hydraulic variable unit 32 of the stepless speed regulation mechanism through the third connecting gear 34, and receives the power after the stepless speed regulation mechanism has adjusted the speed. The planet carrier 45 serves as the supporting structure of the planetary gears 43, and fixes the axles of each planetary gear 43 through the support arms to ensure the relative position stability of the planetary gears 43 during the movement, and converts the revolution motion of the planetary gears 43 into the overall rotation of the planet carrier 45, and its output end is connected to the differential 51 through transmission.

[0062] In the planetary gear train 40 of this embodiment, the sun gear 42 and the internal gear ring 44 respectively receive two-way power inputs from the first gear set and the continuously variable speed mechanism. The planet carrier 45 serves as the output member, enabling the planetary gear train 40 to not only achieve power confluence but also perform speed synthesis. When the speeds of the sun gear 42 and the internal gear ring 44 are different, the planet gears 43 will generate relative motion. According to the planetary gear transmission principle, the output speed of the planet carrier 45 will be the weighted average of the speeds of the sun gear 42 and the internal gear ring 44, and the specific ratio depends on the geometric parameters of the planetary gear train 40, which is not specifically defined in this embodiment.

[0063] Preferably, the connection between the planetary gear train 40 and the differential 51 adopts a spline or flange structure, which not only ensures reliable power transmission but also facilitates disassembly, assembly, and maintenance.

[0064] In a preferred embodiment, the differential 51 is arranged at the output end of the planet carrier 45 and serves as the final output mechanism of the continuously variable speed electric drive axle system. Preferably, the differential 51 adopts a standard bevel gear differential structure, which at least includes a differential housing and half axle gears. Among them, the differential housing is in transmission connection with the planet carrier 45 and is used to receive power from the planetary gear train 40; the half axle gears are connected to the left and right output half axles and are responsible for transmitting power to the wheels 61.

[0065] In a preferred embodiment, the continuously variable speed electric drive axle system further includes a locking mechanism. The locking mechanism is connected to the internal gear ring 44 and is used to lock the internal gear ring 44 in a zero-speed state under preset conditions. When the locking mechanism works, power is directly transmitted from the sun gear 42 to the planet carrier 45.

[0066] Specifically, the purpose of setting the locking mechanism is mainly to provide a direct mechanical transmission path to bypass the continuously variable speed mechanism under specific working conditions to improve the overall efficiency of the system. At the same time, it also provides an emergency transmission path in case of system failure, enhancing the reliability of the whole vehicle. Optionally, the locking mechanism can adopt an electromagnetic or hydraulically driven friction plate type or tooth type clutch structure, which is installed on the outer circumference or end face of the internal gear ring 44 and realizes reliable locking of the internal gear ring 44 by combining with a reaction component fixed on the drive axle housing. Since the locking mechanism itself can be directly purchased, the specific structural details or structural types of the locking mechanism are not specifically defined in this embodiment, and those skilled in the art can make corresponding selections according to actual needs.

[0067] According to the planetary gear transmission theory, when the internal gear ring 44 is locked to a zero rotational speed, the rotation of the sun gear 42 will directly drive the planet gear 43 to revolve around the sun gear 42, and then drive the planet carrier 45 to rotate, forming a pure mechanical transmission path with a fixed transmission ratio. At this time, there is a fixed reduction ratio between the rotational speed of the planet carrier 45 and the rotational speed of the sun gear 42, and this ratio depends on the tooth number ratio of the sun gear 42 and the planet gear 43. Those skilled in the art can set it according to specific working conditions, and no specific examples will be given here for limitation.

[0068] In a preferred embodiment, the starting conditions of the locking mechanism generally include but are not limited to the following preset conditions: the vehicle reaches a specific speed range, the operating point of the motor is in the efficient region, the vehicle load is stable and has a small change range, there is no frequent acceleration and deceleration requirement, etc. The control system monitors the corresponding parameters in real time and determines whether to start the locking mechanism according to the preset decision logic. When the starting conditions are met, the controller will send an instruction to engage the locking mechanism and at the same time adjust the output rotational speed of the motor 11 to make the system smoothly transition to the locked state.

[0069] In a preferred embodiment, the continuously variable transmission electric drive axle system further includes a power take-off mechanism. The power take-off mechanism is connected to the first gear set and is used to extract part of the power from the first gear set to drive the vehicle auxiliary equipment. At this time, there is no need to additionally configure an independent power source, thereby optimizing the vehicle system architecture and improving the integration degree and space utilization rate.

[0070] In a preferred embodiment, the power take-off mechanism is preferably arranged at the output end of the first gear set and meshes with a certain gear of the first gear set through a specially designed power take-off gear, or is directly connected to a certain shaft of the first gear set through a coaxial coupling, so as to ensure that the auxiliary equipment can always obtain a stable and reliable power input under the condition that the motor works normally.

[0071] Compared with the prior art, the continuously variable transmission electric drive axle system of the embodiment of the present invention adopts a power split structure, splits the power of the motor 11 through the first gear set to the continuously variable speed mechanism and the planetary gear train 40, and then couples and outputs it to the differential 51 by the planetary gear train 40, realizing high-efficiency power transmission. The continuously variable speed mechanism makes the rotational speed of the internal gear ring 44 steplessly adjustable by adjusting the displacement of the hydraulic variable unit, can precisely control the output rotational speed, meet the requirements of different vehicle working conditions, and at the same time keep the motor 11 working in the high-efficiency range, improving the energy utilization rate of the system.

[0072] Embodiment 2

[0073] An embodiment of the present invention provides a continuously variable electric drive axle system. Different from the above-mentioned Embodiment 1, the embodiment of the present invention further includes a stepped speed regulation mechanism. Since the motor 11, the first gear set, the continuously variable speed regulation mechanism, the planetary gear train 40 and the differential 51 in this system are the same as those in the above-mentioned Embodiment 1, the technical features recorded in Embodiment 1 can be naturally inherited in this embodiment and will not be described in detail one by one.

[0074] As Figure 2 , in a preferred embodiment, the stepped speed regulation mechanism in the continuously variable electric drive axle system is arranged between the differential 51 and the planet carrier 45, and is used to provide additional speed change gears on the basis of continuously variable speed, forming a "continuously variable + stepped" composite speed change system, so as to fully combine the smoothness of continuously variable speed and the high efficiency of stepped speed change, and achieve a comprehensive performance with a wider speed ratio range and higher transmission efficiency.

[0075] Preferably, the stepped speed regulation mechanism includes a shift actuator 76, a shift sleeve 77 and a second gear set. The second gear set includes a fourth connecting gear 71, a fifth connecting gear 72, a third transmission gear 73, a fourth transmission gear 74, and a fifth transmission gear 75. Among them, the fourth connecting gear 71 and the fifth connecting gear 72 are coaxially and fixedly connected to the planet carrier 45 and receive the power output from the planetary gear train 40. The fourth connecting gear 71 meshes with the third transmission gear 73 for transmission, the fifth connecting gear 72 meshes with the fourth transmission gear 74 for transmission, and the transmission ratios of the fourth connecting gear 71 and the fifth connecting gear 72 are different, so as to constitute two transmission paths with different transmission ratios. The third transmission gear 73, the fourth transmission gear 74 and the fifth transmission gear 75 are coaxially and fixedly connected, and the fifth transmission gear 75 is in transmission connection with the differential 51.

[0076] When the stepped speed regulation mechanism is working, the shift sleeve 77 can move axially along the transmission shaft under the drive of the shift actuator 76, and selectively form a power closed loop with the third transmission gear 73 or the fourth transmission gear 74 to realize the switching between different gears.

[0077] In a preferred embodiment, the transmission ratio of the fourth connecting gear 71 to the third transmission gear 73 is greater than the transmission ratio of the fifth connecting gear 72 to the fourth transmission gear 74. When the shift sleeve 77 engages with the third transmission gear 73, the power transmission path is successively the planet carrier 45, the fourth connecting gear 71, the third transmission gear 73, the fifth transmission gear 75 and the differential 51, and a low gear is formed at this time. When the shift sleeve 77 engages with the fourth transmission gear 74, the power transmission path is the planet carrier 45, the fifth connecting gear 72, the fourth transmission gear 74, the fifth transmission gear 75, and the differential 51, and a high gear is formed at this time.

[0078] In this embodiment, through the two gears provided by the stepped speed regulation mechanism, the total transmission ratio range of the system is greatly expanded, which can meet the full working condition requirements from low-speed high torque to high-speed cruising; for example, in the high-speed cruising working condition, by selecting the high-speed gear, the reduction ratio of the stepless speed regulation mechanism can be reduced, so that the first hydraulic variable unit 31 and the second hydraulic variable unit 32 work in a higher efficiency range; in the climbing or heavy-load working condition, the low-speed gear can provide a greater output torque capacity.

[0079] In this embodiment, the stepped speed regulation mechanism, as an important part of the stepless speed change electric drive axle system, significantly improves the overall performance and applicability of the system through its collaborative work with the stepless speed regulation mechanism, providing a more efficient and reliable power transmission solution for various special vehicles and construction machinery.

[0080] In a preferred implementation manner, the stepless speed change electric drive axle system in this embodiment can also be provided with a power take-off mechanism and / or a locking mechanism, and the specific settings are the same as those in the above-mentioned Embodiment 1, which will not be elaborated here.

[0081] Example 3

[0082] The embodiment of the present invention provides a vehicle configured with the stepless speed change electric drive axle system described in the above-mentioned Embodiment 1 or Embodiment 2. Preferably, the vehicle in this embodiment is a pure electric drive commercial vehicle, such as an electric truck, an electric bus, an electric transport vehicle, an electric tractor, etc. Based on the above electric drive axle system, the vehicle can meet the driving requirements under different working conditions.

[0083] Although example embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above example embodiments are merely exemplary and are not intended to limit the scope of the present application thereto. Those of ordinary skill in the art can make various changes and modifications therein without departing from the scope and spirit of the present application. All such changes and modifications are intended to be included within the scope of the present application as claimed by the appended claims.

[0084] In the specification provided herein, a large number of specific details are set forth. However, it can be understood that the embodiments of the present application can be practiced without these specific details. In some instances, well-known methods, structures, and technologies have not been shown in detail so as not to obscure the understanding of this specification.

[0085] Similarly, it should be understood that, for the purpose of streamlining the present application and facilitating the understanding of one or more of the various inventive aspects, in the description of the exemplary embodiments of the present application, the various features of the present application are sometimes grouped together into a single embodiment, figure, or description thereof. However, the methods of the present application should not be construed as reflecting an intention that the claimed present application requires more features than are expressly recited in each claim. Rather, as reflected by the corresponding claims, the inventive point lies in that the corresponding technical problems can be solved with features less than all the features of a single disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into the detailed description, where each claim itself serves as a separate embodiment of the present application.

[0086] Those skilled in the art can understand that, except for features that are mutually exclusive, any combination can be adopted to combine all the features disclosed in this specification (including the accompanying claims, abstract, and drawings) and all the processes or units of any method or device so disclosed. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) can be replaced by an alternative feature that provides the same, equivalent, or similar purpose.

Claims

1. A continuously variable electric drive axle system, characterized in that: include: - Motor, used to provide power; - a first gear set, which is transmission-connected to the motor and distributes power; - a stepless speed regulating mechanism, whose input end is connected to the first gear set for achieving stepless speed change; - a planetary gear train, comprising a sun gear, planetary gears, an inner gear ring and a planet carrier, wherein the sun gear is drivingly connected to the first gear set, and the inner gear ring is drivingly connected to the output end of the stepless speed regulating mechanism; - a differential, drivingly connected to the planetary carrier, for outputting power to the wheels; The first gear set diverts power to the stepless speed regulating mechanism and the sun gear, and the two powers are coupled in the planetary gear system and output from the planet carrier to the differential; the stepless speed regulating mechanism adjusts the displacement and the speed so that the speed of the inner ring gear can be adjusted steplessly, thereby realizing stepless regulation of the output speed of the planet carrier.

2. The continuously variable electric drive axle system according to claim 1, characterized in that: The input shaft of the motor is transmission-connected to the first gear set via a constant meshing gear; The first gear set includes a first transmission gear and a second transmission gear that are coaxially fixedly connected. The first transmission gear is transmission-connected to the stepless speed regulating mechanism, and the second transmission gear is transmission-connected to the sun gear.

3. The continuously variable electric drive axle system according to claim 2, characterized in that: The transmission ratios of the first transmission gear and the second transmission gear are different, so that the power transmitted to the stepless speed regulation mechanism and the sun gear is distributed according to a preset ratio to achieve optimal power distribution efficiency.

4. The continuously variable electric drive axle system according to claim 3, characterized in that: The stepless speed regulating mechanism comprises a first hydraulic variable unit and a second hydraulic variable unit connected to each other; The input end of the first hydraulic variable unit is transmission-connected to the first transmission gear via a first connecting gear, and is used to receive power input; The output end of the second hydraulic variable unit is transmission-connected to the inner gear ring through a third connecting gear, so as to output the power after speed change adjustment to the inner gear ring.

5. The continuously variable electric drive axle system according to claim 4, characterized in that: The first hydraulic variable unit and the second hydraulic variable unit both include a variable swash plate type hydraulic pump-motor, and the displacement and speed are changed by adjusting the swash plate angle; The adjustment of the swash plate angle is determined by a control system based on a comprehensive judgment of the vehicle driving state, load demand and / or motor efficiency, so that the motor can maintain operation in a high efficiency range while meeting the vehicle power demand.

6. The continuously variable electric drive axle system according to claim 1, characterized in that: It also includes a locking mechanism, which is connected to the inner gear ring and is used to lock the inner gear ring at a zero speed state under preset conditions; when the locking mechanism is working, power is directly transmitted from the sun gear to the planet carrier.

7. The continuously variable electric drive axle system according to claim 1, characterized in that: It also includes a power take-off mechanism, which is connected to the first gear set and is used to take part of the power from the first gear set to drive vehicle auxiliary equipment.

8. The continuously variable electric drive axle system according to any one of claims 1 to 7, characterized in that: It also includes a stepped speed regulating mechanism, which is arranged between the differential and the planetary carrier and is used to provide additional speed gears on the basis of continuously variable speed change.

9. The continuously variable electric drive axle system according to claim 8, characterized in that: The step-by-step speed regulating mechanism comprises a shift actuator, a shift sleeve and a second gear set, wherein the second gear set comprises a fourth connecting gear, a fifth connecting gear, a third transmission gear, a fourth transmission gear and a fifth transmission gear; The fourth connecting gear and the fifth connecting gear are coaxially fixedly connected with the planet carrier, the fourth connecting gear is meshed with the third transmission gear for transmission, the fifth connecting gear is meshed with the fourth transmission gear for transmission, and the transmission ratios of the fourth connecting gear and the fifth connecting gear are different; The shift actuator is used to control the movement of the shift sleeve, and the shift sleeve can be selectively connected to the third transmission gear or the fourth transmission gear; The third transmission gear, the fourth transmission gear and the fifth transmission gear are coaxially fixedly connected, and the fifth transmission gear is drivingly connected to the differential.

10. A vehicle, characterized in that: The vehicle includes a continuously variable electric drive axle system as described in any one of claims 1 to 9.

Images