Stepless speed change electric drive axle system and vehicle

Abstract

The utility model relates to a stepless speed change electric drive axle system and a vehicle, and the system comprises a power source which is used for providing power; the power distribution mechanism is in transmission connection with the power source and divides power into two paths; the input end of the stepless speed regulating mechanism is connected with the power distribution mechanism, and the stepless speed regulating mechanism is used for realizing stepless speed change; the power coupling mechanism at least comprises a first motion component, a second motion component and a third motion component, the first motion component is in transmission connection with the power distribution mechanism, the second motion component is in transmission connection with the output end of the stepless speed regulation mechanism, and the third motion component is used for outputting coupled power; the output component is in transmission connection with the third moving component and used for outputting power to wheels; the power distribution mechanism distributes power to the stepless speed regulating mechanism and the first moving component, and the two paths of power are coupled in the power coupling mechanism and output to the output mechanism through the third moving component.

Description

TECHNICAL FIELD

[0001] The utility model relates to vehicle power system technical field especially relates to a kind of stepless speed change electric drive axle system and vehicle. BACKGROUND

[0002] At present, heavy commercial vehicles of pure electric drive mainly adopt central electric drive and electric drive axle two driving modes to realize vehicle power transmission, wherein, electric drive axle has smaller installation space requirement and higher integration, and shows greater development potential in practical application. The electric drive axle commonly seen in the market adopts the step-variable structure of two gears to four gears, and adapts to different driving conditions by gear shifting.

[0003] However, this step-variable structure has obvious deficiencies: first, the limited gears are difficult to meet the demand of complex and changeable conditions, especially under the conditions of frequent start-stop, climbing or heavy load; second, power interruption or gear shifting impact may occur during gear shifting, affecting the smoothness of vehicle operation; third, the fixed transmission ratio makes the motor unable to work in the high-efficiency area all the time, reducing the overall energy efficiency of the system.

[0004] Some stepless speed change technologies for traditional internal combustion engine drive have appeared in the prior art, such as hydraulic mechanical stepless speed changer applied to tractor, but these technologies are mainly designed for internal combustion engine characteristics, and have complex structure and high control difficulty, and are difficult to be directly applied to electric drive system.

[0005] The working characteristics of motor and internal combustion engine are significantly different: the motor has a wide high-efficiency interval, but its efficiency will decrease significantly under ultra-low speed or ultra-high speed conditions; at the same time, the maximum output torque characteristics of the motor under different speeds are also different from those of the internal combustion engine. Therefore, it is of great practical significance to develop a special stepless speed change technology for electric drive system, so that the motor can always work in high-efficiency interval and meet the power demand of vehicle under various conditions.

[0006] Therefore, there is an urgent need for a stepless speed change electric drive axle system with simple structure, convenient control and high efficiency to meet the power demand under different conditions and keep the motor working in high-efficiency interval. INVENTION CONTENTS

[0007] The utility model discloses a stepless speed change electric drive axle system and vehicle, aims at solving the technical problem existing in prior art.

[0008] The utility model adopts the following technical scheme:

[0009] On the one hand, the utility model embodiment provides a kind of stepless speed change electric drive axle system, comprising:

[0010] -power source, for providing power power;

[0011] a power distribution mechanism, which is in driving connection with the power source and splits the power into two paths;

[0012] a stepless speed regulation mechanism, an input end of which is connected with the power distribution mechanism, for realizing stepless speed regulation;

[0013] a power coupling mechanism, which at least includes a first movement component, a second movement component and a third movement component, the first movement component is in driving connection with the power distribution mechanism, the second movement component is in driving connection with an output end of the stepless speed regulation mechanism, and the third movement component is used for outputting the coupled power;

[0014] an output component, which is in driving connection with the third movement component, for outputting the power to the wheels;

[0015] The power distribution mechanism splits the power to the stepless speed regulation mechanism and the first movement component, the two paths of power are coupled in the power coupling mechanism, and are outputted to the output mechanism by the third movement component.

[0016] As a preferred technical solution, the power source includes a motor, and the power distribution mechanism includes a first gear set, an input shaft of the motor is in driving connection with the first gear set through a constant mesh gear;

[0017] The first gear set includes coaxially fixed first transmission gears and second transmission gears, the first transmission gears are in driving connection with the stepless speed regulation mechanism, and the second transmission gears are in driving connection with the first movement component.

[0018] As a preferred technical solution, the transmission ratio of the first transmission gears and the second transmission gears is different, so that the power transmitted to the stepless speed regulation mechanism and the first movement component is distributed according to a preset ratio, to realize 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 unit connected with each other;

[0020] An input end of the first hydraulic variable unit is in driving connection with the first transmission gears through a first connecting gear, for receiving power input;

[0021] An output end of the second hydraulic variable unit is in driving connection with the second movement component through a third connecting gear, for outputting the power after speed regulation to the second movement component.

[0022] As a preferred technical solution, the first hydraulic variable unit and the second hydraulic variable unit each include a variable swash plate type hydraulic pump-motor, and the displacement and the rotating 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 is kept in a high-efficiency interval and the vehicle power demand is met.

[0024] As a preferred technical solution, the power coupling mechanism further comprises a locking mechanism connected with the second motion member, for locking the second motion member in a zero speed state under a preset condition.

[0025] As a preferred technical solution, the power coupling mechanism further comprises a power taking mechanism connected with the power distribution mechanism, for taking part of the power from the power distribution mechanism to drive vehicle auxiliary equipment.

[0026] As a preferred technical solution, the power coupling mechanism comprises a planetary gear train, the first motion member comprises a sun gear, the second motion member comprises an inner ring gear, and the third motion member comprises a planet carrier; the planetary gear train further comprises a planet gear.

[0027] As a preferred technical solution, the power coupling mechanism further comprises a stepped speed regulation mechanism arranged between the output member and the third motion member, for providing additional speed regulation gears on the basis of the continuously variable transmission.

[0028] As a preferred technical solution, the stepped speed regulation mechanism comprises a gear shift actuator, a gear shift sleeve and a second gear set, the second gear set comprising a fourth connecting gear, a fifth connecting gear, a third transmission gear, a fourth transmission gear and a fifth transmission gear.

[0029] The fourth connecting gear and the fifth connecting gear are coaxially fixedly connected with the third motion member, the fourth connecting gear is in transmission connection with the third transmission gear, the fifth connecting gear is in transmission connection with the fourth transmission gear, and the transmission ratio of the fourth connecting gear and the fifth connecting gear is different.

[0030] The gear shift actuator is used for controlling the movement of the gear shift sleeve, and the gear shift sleeve is selectively in transmission connection with the third transmission gear or the fourth transmission gear.

[0031] The third transmission gear, the fourth transmission gear and the fifth transmission gear are coaxially fixedly connected, and the fifth transmission gear is in transmission connection with the output member.

[0032] In another aspect, the utility model embodiment further provides a vehicle, the vehicle comprises the continuously variable transmission electric drive axle system as any one of the above.

[0033] The above-mentioned embodiment of the utility model has the following advantages or beneficial effects:

[0034] The utility model mainly provides a kind of continuously variable transmission electric drive axle system and vehicle, compared with prior art, the continuously variable transmission electric drive axle system of utility model embodiment adopts power split structure, motor power is shunted to continuously variable speed mechanism and planetary gear train by first gear set, then is coupled to differential by planetary gear train, realizes the power transmission of high efficiency.The output speed can be accurately controlled by adjusting the displacement of hydraulic variable unit in continuously variable speed mechanism, meet the different working condition demand of vehicle, simultaneously make motor keep in high efficiency interval work, improve system energy utilization.

[0035] In addition, the utility model can also selectively configure locking mechanism, power take-off mechanism and step speed regulation mechanism;Among them, locking mechanism can reduce the operating loss of hydraulic system, power take-off mechanism can take part of power to drive auxiliary equipment, and step speed regulation mechanism provides additional speed gear on the basis of continuously variable transmission, expands the overall speed range of system. These structure designs provide higher adaptability and functional diversity for vehicle, and are suitable for complex working conditions and extreme working environment. BRIEF DESCRIPTION OF DRAWINGS

[0036] In order to more clearly illustrate the technical scheme of the utility model embodiment, the drawings needed to be used in the embodiment description will be briefly introduced below, which constitutes a part of the utility model, the schematic embodiment of the utility model and its explanation and interpretation of the utility model, and do not constitute improper limitation on the utility model. In the drawings:

[0037] Figure 1 It is the structure schematic view of continuously variable transmission electric drive axle system provided in the utility model embodiment 1;

[0038] Figure 2 It is the structure schematic view of continuously variable transmission electric drive axle system provided in the utility model embodiment 2.

[0039] Mark explanation:

[0040] Motor 11, input shaft 12, first transmission gear 21, second transmission gear 22, always 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, inner tooth ring 44, planet 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, gear shifting actuator 76, gear shifting sleeve 77. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical scheme and advantages of the utility model clearer, the utility model technical scheme will be described clearly and completely in combination with specific embodiments of the utility model and corresponding drawings below. In the description of the utility model, it needs to be indicated that the term "or" is usually used in the meaning of including "and / or", unless the content is explicitly indicated otherwise.

[0042] In the description of the present application, the terms "first", "second" and the like are only used for differentiation in description, and cannot be understood as indicating or implying relative importance.

[0043] Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by the person skilled in the art without creative labor belong to the protection scope of the utility model.

[0044] Embodiment 1

[0045] At present, pure electric drive commercial vehicles, especially heavy commercial trucks, mine trucks, forklifts and engineering vehicles such as loaders, are gradually becoming an important development direction in the field of transportation and engineering machinery. Such vehicles usually have the characteristics of large load, complex working conditions and high requirements for power performance. The design of the driving system needs to meet the diversified working requirements and ensure the maximum energy utilization efficiency. However, the common electric drive axle in the market usually adopts a two-gear to four-gear stepped speed structure, which is difficult to meet the complex and variable working condition requirements, and the motor 11 cannot always work in the high efficiency interval.

[0046] In order to solve the problems existing in the prior art, the utility model embodiment provides a kind of continuously variable transmission electric drive axle system, which includes motor 11, first gear set, continuously variable speed mechanism, planetary gear train 40 and differential 51, the power power output by motor 11 is shunted to continuously variable speed mechanism and planetary gear train 40 by first gear set, and then coupled to differential 51 by planetary gear train 40 to realize continuously variable speed.

[0047] As Figure 1 In a preferred embodiment, the motor 11 is arranged at the input end of the entire continuously variable transmission electric drive axle system for inputting power to the system; the first gear set is in transmission connection with the motor 11 and distributes the power; the input end of the continuously variable speed mechanism is connected with the first gear set; the planetary gear train 40 includes a sun gear 42, a planet gear 43, an inner ring gear 44 and a planet carrier 45, the sun gear 42 is in transmission connection with the first gear set, and the inner ring gear 44 is in transmission connection with the output end of the continuously variable speed mechanism; the differential 51 is in transmission connection with the planet carrier 45 for outputting power to the wheels 61.

[0048] The first gear set splits the power to the stepless speed regulation mechanism and the sun gear 42, the two-way power is coupled in the planetary gear system 40, and then output to the differential 51 by the planet carrier 45; the stepless speed regulation mechanism adjusts the displacement and the rotating speed, so that the rotating speed of the inner ring gear 44 is steplessly adjustable, to realize the stepless adjustment of the output rotating speed of the planet carrier 45.

[0049] In a preferred embodiment, the motor 11 can be selected from a permanent magnet synchronous motor or an induction motor, and the specific specifications or power levels can be adaptively selected according to the vehicle requirements, which are not limited in the present embodiment; the motor 11 is in driving connection with the first gear set through the input shaft 12 thereof, to ensure the stability and reliability of power transmission.

[0050] In a preferred embodiment, the input shaft 12 of the motor 11 is coaxially fixedly connected with the first gear set, to realize direct transmission; 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, the driving gear is in meshing connection with the always-meshing gear 23 on the first gear set, and power transmission is realized through gear meshing.

[0051] It should be noted that, although from the perspective of the motor 11 itself, the shaft connected with the first gear set is the output shaft of the motor 11, from the perspective of the entire stepless variable speed electric drive axle system, since the shaft is the shaft that inputs power to the system, and in order to distinguish 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 the present specification.

[0052] In a preferred embodiment, the first gear set includes the first transmission gear 21 and the second transmission gear 22 which are coaxially fixedly connected, and both of which are coaxially fixedly connected with the always-meshing gear 23, and those skilled in the art should understand that the so-called coaxial fixed connection means that multiple gears share an axis, and there is no possibility of relative rotation between multiple gears.

[0053] In a preferred embodiment, the first transmission gear 21 is in driving engagement with the first connecting gear 33, and the first connecting gear 33 is arranged at the input end of the stepless speed regulation mechanism, to realize power transmission to the stepless speed regulation mechanism; the second transmission gear 22 is in driving engagement with the second connecting gear 41, and the second connecting gear 41 is arranged at the input end of the sun gear 42, to realize power transmission to the sun gear 42 in the planetary gear system 40.

[0054] Alternatively, the transmission ratio of the first transmission gear 21 and the second transmission gear 22 can be configured to be the same or different.

[0055] Preferably, the transmission ratio of the first transmission gear 21 and the second transmission gear 22 is configured to be different to achieve optimal power distribution efficiency. Those skilled in the art understand that the transmission ratio refers to the diameter ratio or the number of teeth ratio of two mutually meshing gears, which determines the relationship between the input and output rotational speed. Specifically, the transmission ratio of the first transmission gear 21 refers to the number of teeth ratio or the 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 number of teeth ratio or the diameter ratio between the second transmission gear 22 and the second connecting gear 41.

[0056] By configuring the transmission ratio of the first transmission gear 21 and the second transmission gear 22, the power transmitted to the continuously variable transmission mechanism and the sun gear 42 can be distributed in a predetermined ratio. For example, according to the efficiency curve under common working conditions of the vehicle, 60%-70% of the power can be transmitted to the continuously variable transmission 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 no longer exemplified one by one, and those skilled in the art can make adaptive adjustments according to actual needs.

[0057] In a preferred embodiment, the continuously variable transmission mechanism includes a first hydraulic variable unit 31 and a second hydraulic variable unit 32 connected to each other. The first hydraulic variable unit 31 serves as the input end of the continuously variable transmission mechanism and is drivingly connected to 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 continuously variable transmission mechanism and is drivingly connected to the gear on the inner ring 44 through the third connecting gear 34 for outputting the power after speed adjustment to the inner ring 44.

[0058] In a preferred embodiment, the first hydraulic variable unit 31 and the second hydraulic variable unit 32 each include a variable swash plate hydraulic pump-motor, and the two variable swash plate 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, and the second hydraulic variable unit 32 converts the hydraulic energy back into mechanical power and outputs it to the inner ring 44 of the planetary gear train 40. The displacement and rotational speed are changed 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 is kept working in the high-efficiency interval while meeting the vehicle power demand.

[0059] Specifically, the variable swash plate hydraulic pump-motor realizes stepless speed change by adjusting the swash plate angle, has a wide speed change range and a more rapid response, and can be continuously adjusted within a transmission ratio range of -1 to +1, far exceeding the capability of conventional mechanical transmissions. In addition, the hydraulic system has better overload protection capability and smooth power transmission characteristics, can effectively absorb impact loads, and has a longer service life.

[0060] In actual operation, the controller will collect information such as vehicle speed, accelerator pedal position, slope, load, etc. in real time, combine the preset motor 11 efficiency curve or mapping table, determine the optimal motor operating point under the current working condition, and then adjust the swash plate angle of the first hydraulic variable unit 31 and the second hydraulic variable unit 32, so that the control system can accurately adjust the transmission ratio, so that the motor 11 always works in the high-efficiency area. For example, in the low-speed high-torque demand scenario, the system will increase the transmission ratio to provide sufficient torque; when cruising at high speed, the transmission ratio is reduced to reduce the motor 11 speed and reduce energy loss. This control strategy based on multi-parameter optimization can significantly improve the efficiency of electric energy utilization while meeting the power demand of the vehicle, and prolong the pure electric cruising range.

[0061] It should be noted that the embodiments of the utility model do not further limit the specific specifications and technical parameters of the variable swash plate type hydraulic pump-motor, and the person skilled in the art can select appropriate specifications of the hydraulic element according to the actual application scene, vehicle tonnage, load characteristics, power demand and other factors, and adaptively design and select the displacement range, maximum working pressure and efficiency characteristics to meet the application requirements of different types of vehicles.

[0062] In a preferred embodiment, the planetary gear train 40 is used as the core power coupling device of the stepless variable speed electric drive axle system, adopting a single-stage planetary gear structure, wherein the sun gear 42 is located at the center of the planetary gear train 40 and is drivingly connected with the second transmission gear 22 through the second connecting gear 41 to receive part of the power distributed from the first gear set; a plurality of planetary gears 43 are uniformly distributed around the sun gear 42, and the outer periphery of the planetary gears 43 is meshed with the inner teeth of the inner ring gear 44 while the outer teeth of the planetary gears 43 are meshed with the sun gear 42, the planetary gears 43 can rotate around their own axes and revolve around the sun gear 42 as a whole; the inner ring gear 44 surrounds the outer periphery of the entire planetary gear train 40, and the inner surface thereof is provided with inner teeth and is drivingly connected with the second hydraulic variable unit 32 of the stepless speed regulation mechanism through the third connecting gear 34 to receive the power after speed regulation by the stepless speed regulation mechanism; the carrier 45 is a supporting structure of the planetary gears 43, and the axes of the planetary gears 43 are fixed by the supporting arms to ensure the relative position stability of the planetary gears 43 during movement, and the planetary gears 43 are drivingly connected with the differential 51.

[0063] In the planetary gear train 40 of the embodiment, the sun gear 42 and the inner ring gear 44 receive two power inputs from the first gear set and the stepless speed regulation mechanism respectively, and the planet carrier 45 serves as an output component, so that the planetary gear train 40 can realize both power merging and speed synthesis; when the rotational speed of the sun gear 42 and the rotational speed of the inner ring gear 44 are different, the planetary gear 43 will produce relative motion, and according to the planetary gear transmission principle, the output rotational speed of the planet carrier 45 will be a weighted average of the rotational speed of the sun gear 42 and the rotational speed of the inner ring gear 44, and the specific proportion depends on the geometric parameters of the planetary gear train 40, which are not specifically limited in the embodiment.

[0064] 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 and maintenance.

[0065] 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 stepless 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 shaft gears, wherein the differential housing is in transmission connection with the planet carrier 45 for receiving power from the planetary gear train 40; the half shaft gears are connected with the left and right output half shafts and are responsible for transmitting power to the wheels 61.

[0066] In a preferred embodiment, the stepless variable speed electric drive axle system further includes a locking mechanism connected with the inner ring gear 44 for locking the inner ring gear 44 at zero rotational speed under preset conditions; when the locking mechanism works, power is directly transmitted from the sun gear 42 to the planet carrier 45.

[0067] Specifically, the main purpose of the locking mechanism is to provide a direct mechanical transmission path that bypasses the stepless speed regulation mechanism under certain working conditions to improve the overall efficiency of the system, and also provides an emergency transmission path when the system fails, thereby enhancing the reliability of the vehicle; optionally, the locking mechanism can adopt a friction plate or tooth clutch structure driven by electricity or hydraulic pressure, which is installed on the outer periphery or end face of the inner ring gear 44, and by combining with the reaction component fixed on the drive axle housing, the reliable locking of the inner ring gear 44 is realized. Since the locking mechanism itself can be directly purchased, the specific structural details or types of the locking mechanism are not specifically limited in the embodiment, and those skilled in the art can make corresponding selection according to actual needs.

[0068] According to the planetary gear transmission theory, when the inner gear ring 44 is locked at zero speed, the rotation of the sun gear 42 will directly drive the planetary gear 43 to revolve around the sun gear 42, and further 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 speed reduction ratio between the rotation speed of the planet carrier 45 and the rotation speed of the sun gear 42, and the ratio depends on the tooth number ratio of the sun gear 42 and the planetary gear 43. Those skilled in the art can set it according to the specific working condition requirements, and here it is not limited to specific examples.

[0069] 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 certain speed range, the motor operating point is in the high efficiency region, the vehicle load is stable and the change range is small, 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 instructions to engage the locking mechanism, and adjust the output speed of the motor 11 to make the system smoothly transition to the locked state.

[0070] In a preferred embodiment, the continuously variable electric drive axle system further comprises a power take-off mechanism connected with the first gear set, which is used to take 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 overall vehicle system architecture and improving the integration and space utilization.

[0071] In a preferred embodiment, the power take-off mechanism is preferably arranged at the output end of the first gear set, and is engaged with a certain gear of the first gear set through a specially designed power take-off gear, or is directly connected with a certain shaft of the first gear set through a coaxial shaft coupling, so as to ensure that the auxiliary equipment can always obtain stable and reliable power input under the condition that the motor is normally working.

[0072] Compared with the prior art, the continuously variable electric drive axle system of the embodiment of the utility model adopts a power split type structure, and the power of the motor 11 is split to the continuously variable speed mechanism and the planetary gear train 40 through the first gear set, and then coupled to the differential 51 by the planetary gear train 40, so as to realize efficient power transmission. The continuously variable speed mechanism can adjust the rotation speed of the inner gear ring 44 steplessly through the displacement of the hydraulic variable unit, can accurately control the output rotation speed, meets the different working condition requirements of the vehicle, and makes the motor 11 work in the high efficiency region, thereby improving the energy utilization rate of the system.

[0073] Example 2

[0074] The utility model discloses an embodiment provides a kind of stepless speed change electric drive axle system, and it is different from above-mentioned embodiment 1, the utility model embodiment further includes step speed regulation mechanism, since motor 11 in the system, first gear set, step speed regulation mechanism, planetary gear train 40 and differential 51 with above-mentioned embodiment 1 remain identical, therefore the technical features recorded in embodiment 1 can be naturally inherited in this embodiment, no longer one by one.

[0075] As Figure 2 In a preferred embodiment, the step speed regulation mechanism in the stepless speed change electric drive axle system is arranged between the differential 51 and the planet carrier 45, for providing additional speed change gears on the basis of stepless speed change, forming a "stepless+step" composite speed change system, to fully combine the smoothness of stepless speed change and the high efficiency characteristics of step speed change, to realize the comprehensive performance of wider speed change ratio range and higher transmission efficiency.

[0076] Preferably, the step speed regulation mechanism includes a shift actuator 76, a shift sleeve 77 and a second gear set, and 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; wherein the fourth connecting gear 71 and the fifth connecting gear 72 are coaxially fixedly connected with the planet carrier 45 and receive power output from the planetary gear train 40; the fourth connecting gear 71 is in meshing transmission with the third transmission gear 73, and the fifth connecting gear 72 is in meshing transmission with the fourth transmission gear 74, and the transmission ratio of the fourth connecting gear 71 and the fifth connecting gear 72 is different, 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 fixedly connected, and the fifth transmission gear 75 is in transmission connection with the differential 51.

[0077] When the step speed regulation mechanism works, the shift sleeve 77 can move axially along the transmission shaft under the drive of the shift actuator 76, to selectively form a power closed loop with the third transmission gear 73 or the fourth transmission gear 74, to realize switching between different gears.

[0078] In a preferred embodiment, the transmission ratio of the fourth connecting gear 71 and the third transmission gear 73 is greater than the transmission ratio of the fifth connecting gear 72 and the fourth transmission gear 74. When the shift sleeve 77 engages with the third transmission gear 73, the power transmission path is the planet carrier 45, the fourth connecting gear 71, the third transmission gear 73, the fifth transmission gear 75 and the differential 51 in sequence, and at this time, a low-speed gear is formed; 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 at this time, a high-speed gear is formed.

[0079] In the embodiment, the total speed ratio range of the system is greatly expanded by two gears provided by the step speed regulation mechanism, which can meet the full working condition requirements from low speed and large torque to high speed cruising; for example, in the high speed cruising working condition, by selecting the high speed gear, the speed 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 interval; in the climbing or heavy load working condition, the low speed gear can provide greater output torque capacity.

[0080] In the embodiment, the step speed regulation mechanism is an important part of the stepless speed regulation electric drive axle system, which significantly improves the overall performance and applicability of the system through the cooperation with the stepless speed regulation mechanism, and provides a more efficient and reliable power transmission solution for various special vehicles and engineering machinery.

[0081] In a preferred embodiment, the stepless speed regulation electric drive axle system in the embodiment can also be provided with a power take-off mechanism and / or a locking mechanism, which are the same as those in the above-mentioned embodiment 1, and will not be described here.

[0082] Example 3

[0083] The utility model embodiment provides a vehicle, the vehicle is provided with the stepless speed regulation electric drive axle system described in embodiment 1 or embodiment 2, preferably, the vehicle in the embodiment is pure electric drive commercial vehicle, such as electric truck, electric bus, electric transport vehicle, electric tractor etc.. Based on the above electric axle system, the vehicle can meet the driving requirements of different working conditions.

[0084] Although the example embodiments have been described herein with reference to the accompanying drawings, it is to be understood that the above-described example embodiments are merely exemplary and are not intended to limit the scope of the present application. Those of ordinary skill in the art can make various changes and modifications without departing from the scope and spirit of the present application. All these changes and modifications are intended to be included within the scope of the present application as claimed in the appended claims.

[0085] In the specification provided herein, a large number of specific details are described. However, it can be understood that the embodiments of the present application can be practiced without these specific details. In some examples, well-known methods, structures and techniques are not shown in detail in order not to obscure the understanding of the present specification.

[0086] Similarly, it is to be understood that the embodiments of the application can alternately be phrased or described substantially similarly to what is claimed by one skilled in the art in related art terminology or art-specific terminology. Thus, no disavowal of claim scope is intended or suggested. Similarly, it is to be understood that, for brevity and clarity, terms of length and / or complexity are not provided where it is not necessary or desirable that the reader have a precise understanding of such terms, as it is not necessary or desirable for those of ordinary skill in the art to convey or comprehend such terms, especially where such terms are used in the recitation of the claims. Thus, it is not intended that the application be limited in scope or meaning to the specific embodiments described herein, but rather, as the scope of the application will be governed by the claims and their equivalents.

[0087] Those skilled in the art will appreciate that all features could be combined in any combination depending on the embodiments of the application chosen and on the desired solution. The person skilled in the art might also appreciate that some of the features could be omitted, depending on the embodiments of the application chosen and on the desired solution. In general, the subject-matter features recited in the claims might be replaced by alternative features having the same, equivalent or similar purpose.

Claims

1. A continuously variable electric drive axle system, characterized in that The application relates to a power distribution mechanism and a power coupling mechanism. The power distribution mechanism comprises a power source for providing power, a power distribution mechanism in driving connection with the power source and distributing power into two paths, a stepless speed regulation mechanism in input connection with the power distribution mechanism and used for realizing stepless speed regulation, and a power coupling mechanism comprising at least a first motion component, a second motion component and a third motion component, wherein the first motion component is in driving connection with the power distribution mechanism, the second motion component is in driving connection with the output end of the stepless speed regulation mechanism, and the third motion component is used for outputting coupled power. The power distribution mechanism distributes power to the stepless speed regulation mechanism and the first motion component, and the two paths of power are coupled in the power coupling mechanism and output to the output mechanism by the third motion component. The power source comprises a motor, and the power distribution mechanism comprises a first gear set, wherein the input shaft of the motor is in driving connection with the first gear set through a constant mesh gear. The first gear set comprises coaxially fixed first and second transmission gears, the first transmission gear is in driving connection with the stepless speed regulation mechanism, and the second transmission gear is in driving connection with the first motion component. The transmission ratio of the first transmission gear to the second transmission gear is different, so that power transmitted to the stepless speed regulation mechanism and the first motion component is distributed in a preset ratio to realize optimal power distribution efficiency. The stepless speed regulation mechanism comprises first and second hydraulic variable units connected with each other.

2. The continuously variable electric drive axle system of claim 1, wherein, The input end of the first hydraulic variable unit is in driving connection with the first transmission gear through a first connecting gear and is used for receiving power input. The output end of the second hydraulic variable unit is in driving connection with the second motion component through a third connecting gear and is used for outputting power adjusted in speed to the second motion component.

3. The continuously variable electric drive axle system of claim 2, wherein, The first and second hydraulic variable units each comprise a variable swash plate type hydraulic pump-motor, and the swash plate angle is adjusted to change the displacement and rotating speed.

4. The continuously variable electric drive axle system of claim 3, wherein, The swash plate angle is adjusted by a control system according to the vehicle driving state, load demand and / or motor efficiency to comprehensively judge that the motor is kept in a high-efficiency interval and meets the vehicle power demand. The application further comprises a locking mechanism in connection with the second motion component and used for locking the second motion component in a zero rotating speed state under preset conditions; when the locking mechanism works, power is directly transmitted from the first motion component to the third motion component. The application further comprises a power taking mechanism in connection with the power distribution mechanism and used for taking part of power from the power distribution mechanism to drive vehicle auxiliary equipment.

5. The continuously variable electric drive axle system of claim 4, wherein, The power coupling mechanism comprises a planetary gear train, the first motion component comprises a sun gear, the second motion component comprises an internal gear ring, the third motion component comprises a planet carrier, and the planetary gear train further comprises a planet gear. ​ 6. The continuously variable electric drive axle system of claim 1, wherein, ​ 7. The continuously variable electric drive axle system of claim 1, wherein, ​ 8. The continuously variable electric drive axle system according to any one of claims 1-7, characterized in that, ​ 9. The continuously variable electric drive axle system of claim 1, wherein, A stepped speed regulation mechanism is further included, which is arranged between the output member and the third motion member, and is used to provide additional speed regulation gears on the basis of the continuously variable speed.

10. The continuously variable electric drive axle system of claim 9, wherein, The stepped speed regulation mechanism comprises a gear shift actuator, a gear shift sleeve and a second gear set, and 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 third motion member, the fourth connecting gear is in transmission connection with the third transmission gear, the fifth connecting gear is in transmission connection with the fourth transmission gear, and the transmission ratio of the fourth connecting gear and the fifth connecting gear is different. The gear shift actuator is used to control the movement of the gear shift sleeve, and the gear shift sleeve is selectively in transmission connection with 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 in transmission connection with the output member.

11. A vehicle characterized by comprising: The vehicle comprises the continuously variable speed electric drive axle system according to any one of claims 1-10.

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