Single-motor five-gear transmission electric drive axle system and vehicle

Abstract

The invention relates to a single-motor five-gear transmission electric drive axle system and a vehicle. The single-motor five-gear transmission electric drive axle system comprises a motor, a first gear shifting mechanism, a second gear shifting mechanism, a planet row assembly and three transmission gear sets. The planet row assembly comprises a sun gear, a planet gear, a planet carrier and a gear ring; the three transmission gear sets comprise a first driving gear, a first driven gear, a second driving gear, a second driven gear and a third driven gear; the motor is connected with the input shaft, and the input shaft is meshed with the normally-meshed intermediate shaft. The first driving gear and the second driving gear are sequentially arranged on the normally engaged intermediate shaft, and the first gear shifting mechanism is arranged between the first driving gear and the second driving gear; the first driven gear and the second driven gear are fixedly arranged on the sun wheel shaft, the sun wheel shaft is sleeved with the third driven gear in an empty mode, and the second gear shifting mechanism is arranged between the third driven gear and the planet row assembly; five transmission gears are formed through cooperation of the first gear shifting mechanism and the second gear shifting mechanism.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle power systems, and in particular to a single-motor five-speed transmission electric drive axle system and a vehicle. Background Art

[0002] With the rapid development of the new energy vehicle industry, pure electric heavy-duty commercial trucks have gradually become an important direction for the development of the industry. At present, most of the single-motor electric drive axles used in pure electric heavy-duty commercial vehicles adopt a layout of less than four gears, and at least two shift actuators and gear sleeves are required to realize the shift function. If the number of gears needs to be increased, three or more shift actuators and gear sleeves are usually required.

[0003] The four-speed electric drive axle in the prior art usually adopts the transmission mode of main and auxiliary gearbox shifting, and realizes the transmission of four gears through two gear shift actuators and gear sleeves. Although this structure can meet the basic transmission requirements, due to the small number of gears, the speed ratio difference between adjacent gears is large, making it difficult to achieve efficient operation of the motor under all working conditions.

[0004] In addition, during the gear shifting process, the existing electric drive axle system often requires a long speed synchronization time due to the large speed ratio difference, which not only affects the vehicle's driving performance, but also produces a large gear shifting shock, reducing the service life and reliability of the transmission system.

[0005] Therefore, there is an urgent need for a new type of electric drive axle system that can not only achieve more gear configurations while maintaining a simple structure and low cost, but also ensure that the vehicle can maintain efficient operation of the motor within the full speed range through a reasonable speed ratio difference design, while also being able to reduce gear shifting shock and improve driving performance. Summary of the invention

[0006] The invention discloses a single-motor five-speed transmission electric drive axle system and a vehicle, aiming to solve the technical problems existing in the prior art.

[0007] The present invention adopts the following technical solutions:

[0008] On the one hand, an embodiment of the present invention provides a single-motor five-speed transmission electric drive axle system, including a motor, a first shift mechanism, a second shift mechanism, a planetary gear assembly, and three transmission gear sets;

[0009] The planetary gear assembly includes a sun gear, planetary gears, a planetary carrier and a ring gear. The sun gear is connected to three transmission gear sets through a sun gear shaft.

[0010] The three transmission gear sets include a first driving gear and a first driven gear, a second driving gear and a second driven gear, and a third driven gear;

[0011] The motor is connected to an input shaft, which is meshed with a constantly meshed intermediate shaft; a first driving gear and a second driving gear are sequentially arranged on the constantly meshed intermediate shaft, and a first shifting mechanism is arranged between the first driving gear and the second driving gear;

[0012] The first driven gear and the second driven gear are fixed on the sun gear shaft, the third driven gear is loosely sleeved on the sun gear shaft, and the second shift mechanism is arranged between the third driven gear and the planetary gear assembly;

[0013] Through the cooperation of the first shift mechanism and the second shift mechanism, five transmission gears are formed.

[0014] As a preferred technical solution, the first shift mechanism includes a first shift actuator, a first shift fork, a first gear sleeve and a first gear hub;

[0015] The first gear hub is fixedly arranged on the constant meshing intermediate shaft, and the first gear hub is arranged between the first driving gear and the second driving gear, and the first gear sleeve is sleeved on the first gear hub and can slide axially;

[0016] The first shift actuator drives the first gear sleeve through the first shift fork, so that the first gear sleeve can be selectively engaged with the first driving gear or the second driving gear.

[0017] As a preferred technical solution, the second shift mechanism includes a second shift actuator, a second shift fork, a second gear sleeve and a second gear hub;

[0018] The second gear hub is fixedly arranged on the sun gear shaft, and the second gear hub is arranged between the engaging teeth of the third driven gear and the planet carrier, and the second gear sleeve is sleeved on the second gear hub and can slide axially;

[0019] The second shift actuator drives the second gear sleeve through the second shift fork, so that the second gear sleeve can be selectively engaged with the third driven gear or the planet carrier.

[0020] As a preferred technical solution, there is a first reduction ratio between the first driving gear and the first driven gear, a second reduction ratio between the second driving gear and the second driven gear, and a third reduction ratio between the third driven gear and the meshing gear of the constantly meshing intermediate shaft;

[0021] The first reduction ratio is greater than the second reduction ratio, and the second reduction ratio is greater than the third reduction ratio.

[0022] As a preferred technical solution, the sun gear shaft is fixedly arranged at one end of the sun gear, and a plurality of planetary gears are arranged around the sun gear;

[0023] The planetary gears are meshed with the sun gear and the ring gear respectively, and the planetary gears are rotatably mounted on the planetary carrier;

[0024] The ring gear is fixed to the housing of the planetary gear assembly, and the output end of the planetary carrier is connected to the differential.

[0025] As a preferred technical solution, when in the first gear transmission state, the first gear sleeve is engaged with the first driving gear, and the second gear sleeve is in the middle position and is not engaged with the third driven gear and the planet carrier.

[0026] As a preferred technical solution, when in the second gear transmission state, the first gear sleeve is engaged with the second driving gear, and the second gear sleeve is in a middle position and is not engaged with the third driven gear and the planet carrier.

[0027] As a preferred technical solution, when in the third gear transmission state, the first gear sleeve is in the middle position and is not engaged with the first driving gear and the second driving gear, and the second gear sleeve is engaged with the third driven gear.

[0028] As a preferred technical solution, when in the fourth gear transmission state, the first gear sleeve is engaged with the first driving gear, and the second gear sleeve is engaged with the planet carrier.

[0029] As a preferred technical solution, when in the fifth gear transmission state, the first gear sleeve is engaged with the second driving gear, and the second gear sleeve is engaged with the planet carrier.

[0030] On the other hand, an embodiment of the present invention further provides a vehicle, comprising a single-motor five-speed transmission electric drive axle system as described in any one of the above items.

[0031] One embodiment of the above invention has the following advantages or beneficial effects:

[0032] The present invention mainly provides a single-motor five-speed transmission electric drive axle system and a vehicle equipped with the electric drive axle system. Compared with the prior art, the electric drive axle system of the embodiment of the present invention only uses two shift actuators and gear sleeves to achieve power transmission of five forward gears. Compared with the solution that requires three or more actuators in the prior art, it not only greatly reduces the system cost and structural complexity, but also improves the reliability and maintenance convenience of the system; at the same time, by setting the third gear as a transition gear between the second gear and the fourth gear, the speed ratio difference between adjacent gears is effectively reduced, and the smaller speed ratio difference can not only shorten the speed regulation synchronization time during the gear shifting process, but also can significantly reduce the gear shifting shock, thereby improving the gear shifting quality and service life of the system.

[0033] In addition, the five-speed transmission structure of the embodiment of the present invention is particularly suitable for pure electric heavy-duty commercial vehicles. It can achieve the unity of economy and reliability while ensuring power performance, so that the commercial vehicle can always keep the motor running in a higher efficiency range under different vehicle speed and load conditions. Through a reasonable speed ratio configuration, it can not only meet the vehicle's demand for high torque when starting, but also ensure the vehicle's power economy when cruising at a higher speed, thereby improving the vehicle's cruising range. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments, which constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions explain the present invention and do not constitute improper limitations on the present invention. In the drawings:

[0035] Figure 1 A schematic diagram of the structure of a single-motor five-speed transmission electric drive axle system provided by an embodiment of the present invention;

[0036] Figure 2 A schematic diagram of power flow of a first gear transmission provided by an embodiment of the present invention;

[0037] Figure 3 A schematic diagram of power flow of a second-gear transmission provided by an embodiment of the present invention;

[0038] Figure 4 A schematic diagram of power flow of a three-speed transmission provided by an embodiment of the present invention;

[0039] Figure 5 A schematic diagram of power flow of a four-speed transmission provided by an embodiment of the present invention;

[0040] Figure 6 A schematic diagram of power flow of a five-speed transmission provided by an embodiment of the present invention.

[0041] Description of reference numerals:

[0042] Motor 11, input shaft 12, constantly meshed intermediate shaft 13, first driving gear 21, first combining tooth 22, first driven gear 23, second driving gear 31, second combining tooth 32, second driven gear 33, third driven gear 41, third combining tooth 42, first shift actuator 51, first shift fork 52, first gear sleeve 53, first gear hub 54, second shift actuator 61, second shift fork 62, second gear sleeve 63, second gear hub 64, sun gear 71, sun gear shaft 72, planetary gear 73, planetary carrier 74, high gear combining tooth 75, ring gear 76, differential 81, left wheel end 91, right wheel end 92. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. In the description of the present invention, it should be noted that the term "or" is usually used in the sense of including "and / or", unless the content clearly indicates otherwise.

[0044] In the description of the present application, the terms “first”, “second”, etc. are only used to distinguish the descriptions and should not be understood as indicating or implying relative importance.

[0045] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] In the field of pure electric heavy-duty commercial vehicles, existing electric drive axles usually adopt a transmission structure within four gears, and need to be equipped with at least two shift actuators and gear sleeves to realize the shift function. When this structure needs to increase the gear position, it is often necessary to increase the number of shift actuators and gear sleeves, resulting in a complex structure and increased costs. In addition, due to the small number of gear positions, the speed ratio difference between adjacent gear positions is large, which not only affects the shift quality, but also makes it difficult to ensure the efficient operation of the motor in the full range of operating conditions.

[0047] To solve the above problems, the embodiment of the present invention provides a single-motor five-speed transmission electric drive axle system, which realizes the transmission of five forward gears through the structure of three-axis parallel shaft and single-stage planetary gear by two sets of shifting mechanisms, which significantly reduces the system cost and structural complexity and effectively reduces the speed ratio difference between adjacent gears compared with the prior art.

[0048] refer to Figure 1 In a preferred embodiment, a single-motor five-speed transmission electric drive axle system includes a motor 11, a three-axis parallel shaft, three sets of transmission gear sets, a planetary gear assembly and two sets of shifting mechanisms, wherein the three-axis parallel shaft is arranged in the system main box, the planetary gear assembly is arranged in the system auxiliary box, and the two sets of shifting mechanisms include a first shifting mechanism and a second shifting mechanism. The first shifting mechanism controls the switching of two gears, and the second shifting mechanism controls the switching of the third gear and the high gear. Through the cooperation of the first shifting mechanism and the second shifting mechanism, the arrangement and combination form the switching of five forward gears.

[0049] It should be noted that the main box and the auxiliary box in the embodiment of the present application are a unified transmission system. It is not for the purpose of simply doubling the gears. The three-axis parallel shaft structure in the main box and the planetary gear assembly in the auxiliary box work together to achieve transmission of five gears.

[0050] In a preferred embodiment, the three-axis parallel shaft includes an input shaft 12, a constantly meshed intermediate shaft 13 and a sun gear shaft 72; the three transmission gear sets include a first driving gear 21 and a first driven gear 23, a second driving gear 31 and a second driven gear 33, and a third driven gear 41, wherein one end of the first driving gear 21 is provided with a first combining tooth 22, one end of the second driving gear 31 is provided with a second combining tooth 32, and one end of the third driven gear 41 is provided with a third combining tooth 42; the planetary gear assembly includes a sun gear 71, a planetary gear 73, a planetary carrier 74 and a ring gear 76, the sun gear 71 is transmission-connected to the three transmission gear sets through the sun gear shaft 72, and one end of the planetary carrier 74 is provided with a high-gear combining tooth 75.

[0051] In a preferred embodiment, the output end of the motor 11 is fixedly connected to the input shaft 12 as the power input end; the input shaft 12 maintains a constant meshing state with the constant meshing intermediate shaft 13, and is used to transmit power to the constant meshing intermediate shaft 13; the first driving gear 21 and the second driving gear 31 are sequentially arranged on the constant meshing intermediate shaft 13, wherein the first driving gear 21 and the second driving gear 31 are loosely arranged on the constant meshing intermediate shaft 13, and one end of the constant meshing intermediate shaft 13 is transmission-connected with the third driven gear 41, that is, the constant meshing intermediate shaft 13 is provided with a gear that is constantly meshed with the third driven gear 41.

[0052] In this embodiment, the motor 11 includes a stator, a rotor, a coil, a rotor shaft and other structures, wherein the rotor shaft serves as the power output end of the motor 11 and is connected to the input shaft 12 in the three-axis parallel shaft. Specifically, the specific model, structure or specification of the motor 11 can be selected and configured according to the power performance requirements of the whole vehicle, and is not specifically limited in this embodiment.

[0053] In a preferred embodiment, the first shifting mechanism is arranged between the first driving gear 21 and the second driving gear 31, and the first shifting mechanism can be selectively engaged with the first combining tooth 22 or the second combining tooth 32 to realize the switching of the two gears of the main box; the power is transmitted to the sun gear shaft 72 through the components on the constantly meshing intermediate shaft 13, the first driven gear 23 and the second driven gear 33 are fixed on the sun gear shaft 72, and the power can be directly transmitted to the planetary gear assembly, the third driven gear 41 is loosely sleeved on the sun gear shaft 72, and the second shifting mechanism is arranged between the third driven gear 41 and the planetary gear assembly, and the second shifting mechanism can be selectively engaged with the third combining tooth 42 or the high gear combining tooth 75 to realize the switching of the third gear and the high gear of the auxiliary box.

[0054] In a preferred embodiment, there is a first reduction ratio between the first driving gear 21 and the first driven gear 23, there is a second reduction ratio between the second driving gear 31 and the second driven gear 33, and there is a third reduction ratio between the third driven gear 41 and the meshing gear of the constantly meshing intermediate shaft 13. It should be understood by those skilled in the art that the greater the reduction ratio, the greater the output torque. In this embodiment, the specific ratio of the reduction ratio and the number of teeth of each transmission tooth are not limited, and those skilled in the art can make adaptive adjustments according to actual application scenarios.

[0055] Preferably, the first reduction ratio, the second reduction ratio and the third reduction ratio are different.

[0056] More preferably, the first reduction ratio is greater than the second reduction ratio, and the second reduction ratio is greater than the third reduction ratio. Among them, the larger first reduction ratio can meet the demand for large torque when heavy commercial vehicles start; the middle second reduction ratio is suitable for frequent acceleration and deceleration conditions under urban conditions; the smaller third reduction ratio is conducive to power economy under high-speed cruising conditions; this decreasing reduction ratio design can ensure a reasonable speed ratio difference between adjacent gears. Through the above three basic reduction ratios, combined with the speed ratio characteristics of the planetary gear assembly, five reasonably distributed transmission gears can be combined to ensure both starting performance and economy.

[0057] In a preferred embodiment, the first shift mechanism includes a first shift actuator 51, a first shift fork 52, a first gear sleeve 53 and a first gear hub 54; wherein the first gear hub 54 is fixedly arranged on the constant meshing intermediate shaft 13, and the first gear hub 54 is arranged between the first driving gear 21 and the second driving gear 31, and a spline is arranged on the outer circumferential surface of the first gear hub 54, the first gear sleeve 53 is sleeved on the first gear hub 54 and can slide axially, and the first gear sleeve 53 has an internal spline that cooperates with the spline, and this spline cooperation can both transmit torque and allow the first gear sleeve 53 to slide freely in the axial direction.

[0058] Internal splines are respectively provided at both ends of the first gear sleeve 53, which can selectively engage with the coupling teeth (i.e., the first coupling teeth 22 and the second coupling teeth 32) on the first driving gear 21 and the second driving gear 31. The first shift actuator 51 drives the first gear sleeve 53 to move axially through the first shift fork 52. When the first gear sleeve 53 moves to the left, the internal spline at the left end thereof engages with the first coupling teeth 22 of the first driving gear 21, and at this time, the first driving gear 21 forms a rigid connection with the constant meshing intermediate shaft 13; when the first gear sleeve 53 moves to the right, the internal spline at the right end thereof engages with the second coupling teeth 32 of the second driving gear 31, and at this time, the second driving gear 31 forms a rigid connection with the constant meshing intermediate shaft 13.

[0059] In this embodiment, the first shift actuator 51 is preferably an electric shift actuator, which has the characteristics of fast response speed and high control accuracy. The electric shift actuator receives the shift instruction through the controller and drives the first shift fork 52 to reciprocate, thereby realizing the precise positioning of the first gear sleeve 53. The first shift fork 52 is provided with a fork groove matched with the first gear sleeve 53, which is used to drive the first gear sleeve 53 to move axially.

[0060] In a preferred embodiment, the second shift mechanism is arranged at the input end of the planetary gear assembly, and its structure also adopts the design form of a synchronizer. Specifically, the second shift mechanism includes a second shift actuator 61, a second shift fork 62, a second gear sleeve 63 and a second gear hub 64; wherein the second gear hub 64 is fixedly arranged on the sun gear shaft 72, and its position is located between the third driven gear 41 of the idle sleeve and the coupling teeth (i.e., the high gear coupling teeth 75) of the planetary carrier 74. A spline is provided on the outer circumferential surface of the second gear hub 64, which cooperates with the inner spline of the second gear sleeve 63.

[0061] Preferably, both ends of the second gear sleeve 63 are provided with internal splines, which can be selectively engaged with the third coupling tooth 42 or the high gear coupling tooth 75. The second shift actuator 61 drives the second gear sleeve 63 to move axially through the second shift fork 62. When the second gear sleeve 63 moves to the left, the internal spline at the left end thereof engages with the third coupling tooth 42 of the third driven gear 41. At this time, the third driven gear 41 forms a rigid connection with the sun gear shaft 72, and the power is transmitted to the planetary gear assembly through the sun gear shaft 72; when the second gear sleeve 63 moves to the right, the internal spline at the right end thereof engages with the high gear coupling tooth 75. At this time, the planet carrier 74 forms a rigid connection with the sun gear shaft 72, and the power is directly transmitted from the sun gear shaft 72 to the planet carrier 74, realizing direct transmission.

[0062] Preferably, the structures and configurations of the second shift actuator 61 and the second shift fork 62 may be the same as or different from those of the first shift actuator 51 and the first shift fork 52 , which are not specifically limited herein.

[0063] In this embodiment, the second shift mechanism allows the power transmission path to be flexibly switched as needed: the power is transmitted to the sun gear shaft 72 through the third driven gear 41, and then outputted through the planetary gear assembly at reduced speed; or the power is directly outputted by directly combining with the planetary carrier 74. By cooperating with the first shift mechanism, five gear shifting and transmission are finally realized.

[0064] In a preferred embodiment, the planetary gear assembly adopts a single planetary gear arrangement, wherein one end of the sun gear shaft 72 is fixedly connected to the sun gear 71 for inputting power; a plurality of planetary gears 73 are arranged around the outer periphery of the sun gear 71, and the planetary gears 73 are rotatably mounted on the planetary carrier 74, and each planetary gear 73 is meshed with the outer teeth of the sun gear 71 and the inner teeth of the ring gear 76 at the same time, thereby forming a complete planetary transmission mechanism. The ring gear 76 is fixed to the housing of the planetary gear assembly as an anti-torsion support, and the planetary carrier 74 is an output member of the planetary gear assembly, and its output end is connected to the input end of the differential 81.

[0065] When power is input from the sun gear 71, under the condition that the ring gear 76 is fixed, the planetary gear 73 rotates around its own axis and revolves around the sun gear 71, driving the planetary carrier 74 to reduce the output; when the second gear sleeve 63 is engaged with the planetary carrier 74, the planetary gear assembly can achieve overall synchronous rotation, that is, direct transmission condition.

[0066] In a preferred embodiment, the differential 81 is arranged after the output end of the planet carrier 74, and is used to distribute power to the left wheel end 91 and the right wheel end 92. Specifically, when the vehicle turns, the differential 81 can automatically adjust the speed difference between the left wheel end 91 and the right wheel end 92, so that the speed of the inner wheel is reduced and the speed of the outer wheel is increased, thereby ensuring smooth turning of the vehicle. At the same time, the differential 81 also has a certain torque distribution function, which can reasonably distribute power to the left wheel end 91 and the right wheel end 92 according to the road adhesion conditions, thereby improving the power performance and driving stability of the whole vehicle.

[0067] In this embodiment, the specific structure and specifications of the differential 81 are no longer specifically limited, and those skilled in the art can make adaptive adjustments according to actual needs.

[0068] In a preferred embodiment, when in the first gear transmission state, the first gear sleeve 53 is engaged with the first coupling tooth 22 of the first driving gear 21, and the second gear sleeve 63 is in the middle position and is not engaged with the third coupling tooth 42 of the third driven gear 41 and the high gear coupling tooth 75 of the planetary carrier 74.

[0069] refer to Figure 2 , where red is the direction of power flow. In the first gear transmission state, the power transmission path is as follows:

[0070] The power output by the motor 11 is first transmitted to the constantly meshing intermediate shaft 13 which is constantly meshing with the input shaft 12. At this time, the first gear sleeve 53 is engaged with the first combining tooth 22, so that the first driving gear 21 is rigidly connected with the constantly meshing intermediate shaft 13. Since the first driving gear 21 is meshed with the first driven gear 23, the power is transmitted to the first driven gear 23 after the first stage of reduction.

[0071] Since the first driven gear 23 is fixed on the sun gear shaft 72, the power is directly transmitted to the sun gear shaft 72, and then transmitted to the sun gear 71 fixed to the sun gear shaft 72. At this time, the second gear sleeve 63 is in the middle position, neither engaged with the third driven gear 41 nor engaged with the planetary carrier 74, so the power can only be transmitted through the transmission path of sun gear 71-planetary gear 73-ring gear 76.

[0072] In the planetary gear assembly, the sun gear 71 drives multiple planetary gears 73 to rotate. Since the ring gear 76 is fixed to the housing, the planetary gears 73 rotate around their own axes and drive the planetary carrier 74 to revolve. This movement mode makes the planetary gear assembly form a speed reduction mechanism, further reducing the output speed and increasing the output torque. Finally, the power output by the planetary carrier 74 is transmitted to the differential 81 and then distributed to the left wheel end 91 and the right wheel end 92.

[0073] Preferably, the first gear is used as the starting gear, and the power undergoes two decelerations during the transmission process, first the deceleration between the first driving gear 21 and the first driven gear 23 (the first reduction ratio is the largest), and then the deceleration of the planetary gear assembly, so it has the largest comprehensive reduction ratio, ensuring that the vehicle has a sufficiently large output torque when starting and climbing.

[0074] In a preferred embodiment, when in the second gear transmission state, the first gear sleeve 53 is engaged with the second driving gear 31 , and the second gear sleeve 63 is in a middle position and is not engaged with the third driven gear 41 and the planet carrier 74 .

[0075] refer to Figure 3 , where red is the power flow direction. In the second gear transmission state, the power transmission path is as follows:

[0076] The power output by the motor 11 is first transmitted to the constantly meshing intermediate shaft 13 which is constantly meshing with the input shaft 12. At this time, the first gear sleeve 53 is engaged with the second combining teeth 32, so that the second driving gear 31 is rigidly connected to the constantly meshing intermediate shaft 13. Since the second driving gear 31 is meshed with the second driven gear 33, the power is transmitted to the second driven gear 33 after the second stage of reduction.

[0077] Since the second driven gear 33 is also fixed on the sun gear shaft 72, the power is directly transmitted to the sun gear shaft 72, and then transmitted to the sun gear 71 fixed to the sun gear shaft 72. At this time, the second gear sleeve 63 is in the middle position, neither engaged with the third driven gear 41 nor engaged with the planetary carrier 74, so the power is still transmitted through the transmission path of sun gear 71-planetary gear 73-ring gear 76.

[0078] In the planetary gear assembly, the transmission principle and process are the same as those of first gear and will not be repeated here.

[0079] Although the power transmission path of the second gear is similar to that of the first gear, both undergo double deceleration through the gear set and the planetary gear set, but since the second reduction ratio is smaller than the first reduction ratio, the comprehensive reduction ratio of the second gear is smaller than that of the first gear, making the second gear more suitable for the acceleration process of the vehicle after starting, which not only ensures sufficient output torque but also increases the output speed.

[0080] In a preferred embodiment, when in the third gear transmission state, the first gear sleeve 53 is in a middle position and is not engaged with the first driving gear 21 and the second driving gear 31 , and the second gear sleeve 63 is engaged with the third driven gear 41 .

[0081] refer to Figure 4 , where red is the power flow direction. In the third gear transmission state, the power transmission path is as follows:

[0082] The power output by the motor 11 is first transmitted to the constantly meshing intermediate shaft 13 which is constantly meshing with the input shaft 12. At this time, the first gear sleeve 53 is neither engaged with the first driving gear 21 nor with the second driving gear 31. The power is directly transmitted to the third driven gear 41 through the constantly meshing intermediate shaft 13. The power is transmitted to the third driven gear 41 after the third stage of reduction.

[0083] Since the second gear sleeve 63 is engaged with the third driven gear 41, the third driven gear 41 which is loosely sleeved on the sun gear shaft 72 forms a rigid connection with the sun gear shaft 72, thereby transmitting power to the sun gear shaft 72, and then to the sun gear 71 which is fixedly connected to the sun gear shaft 72. The power is continuously transmitted through the transmission path of the sun gear 71—the planetary gear 73—the ring gear 76.

[0084] In the planetary gear assembly, the transmission principle is the same as the first two gears: the sun gear 71 drives multiple planetary gears 73 to rotate. Since the ring gear 76 is fixed to the housing, the planetary gear 73 rotates around its own axis and drives the planetary carrier 74 to revolve. The planetary gear assembly continues to play the role of a reducer. The decelerated power is transmitted from the planetary carrier 74 to the differential 81 and finally distributed to the left and right wheels.

[0085] Since the third reduction ratio is smaller than the second reduction ratio, the comprehensive reduction ratio of the third gear is smaller than that of the second gear. As a transitional gear, the design of the reduction ratio of the third gear not only avoids the excessive speed ratio span between the second gear and the fourth gear, but also provides the vehicle with a transmission gear suitable for medium speed conditions, which is conducive to improving the power performance and economy of the vehicle.

[0086] In a preferred embodiment, when in the fourth gear transmission state, the first gear sleeve 53 is engaged with the first driving gear 21 , and the second gear sleeve 63 is engaged with the planet carrier 74 .

[0087] refer to Figure 5, where red is the power flow direction. In the fourth gear transmission state, the power transmission path is as follows:

[0088] The power output by the motor 11 is first transmitted to the constantly meshing intermediate shaft 13 which is constantly meshing with the input shaft 12. At this time, the first gear sleeve 53 is engaged with the first combining tooth 22, so that the first driving gear 21 is rigidly connected with the constantly meshing intermediate shaft 13. Since the first driving gear 21 is meshed with the first driven gear 23, the power is transmitted to the first driven gear 23 after the first stage of reduction.

[0089] Since the first driven gear 23 is fixed on the sun gear shaft 72, the power is directly transmitted to the sun gear shaft 72. At this time, the second gear sleeve 63 is engaged with the high gear combining tooth 75 of the planet carrier 74, so that the planet carrier 74 and the sun gear shaft 72 are rigidly connected. This connection method makes the sun gear shaft 72, sun gear 71, planetary gear 73 and planet carrier 74 form a whole. The planetary gear assembly no longer plays a deceleration role, but rotates synchronously as a whole.

[0090] In the transmission state of the fourth gear, the power is only reduced by one stage between the first driving gear 21 and the first driven gear 23, and then directly output to the differential 81 through the planetary carrier 74 rigidly connected to the sun gear shaft 72, and finally distributed to the left and right wheels. This direct transmission mode of the fourth gear avoids the secondary reduction of the planetary gear assembly, thereby obtaining a higher output speed.

[0091] Although the fourth gear's comprehensive reduction ratio uses the largest first reduction ratio, its comprehensive reduction ratio is actually smaller than that of the third gear because the deceleration effect of the planetary gear assembly is cancelled.

[0092] In a preferred embodiment, when in the fifth gear transmission state, the first gear sleeve 53 is engaged with the second driving gear 31 , and the second gear sleeve 63 is engaged with the planet carrier 74 .

[0093] refer to Figure 6 , where red is the power flow direction. In the fifth gear transmission state, the power transmission path is as follows:

[0094] The power output by the motor 11 is first transmitted to the constantly meshing intermediate shaft 13 which is constantly meshing with the input shaft 12. At this time, the first gear sleeve 53 is engaged with the second combining teeth 32, so that the second driving gear 31 is rigidly connected to the constantly meshing intermediate shaft 13. Since the second driving gear 31 is meshed with the second driven gear 33, the power is transmitted to the second driven gear 33 after the second stage of reduction.

[0095] Since the second driven gear 33 is fixed on the sun gear shaft 72, the power is directly transmitted to the sun gear shaft 72. At this time, the second gear sleeve 63 is engaged with the high gear combination teeth 75 of the planet carrier 74, so that the planet carrier 74 is rigidly connected to the sun gear shaft 72. Similar to the four-speed transmission state, this connection mode makes the sun gear shaft 72, the sun gear 71, the planet gear 73 and the planet carrier 74 form a whole, and the planetary gear assembly no longer plays a deceleration role, but rotates synchronously as a whole.

[0096] In this transmission state, the power is only decelerated between the second driving gear 31 and the second driven gear 33, and then directly output to the differential 81 through the planetary carrier 74 rigidly connected to the sun gear shaft 72, and finally distributed to the left and right wheels, avoiding the secondary deceleration of the planetary gear assembly, thereby obtaining the highest output speed.

[0097] In the five-speed transmission process, not only a smaller second reduction ratio is used, but also the reduction effect of the planetary gear assembly is cancelled. Therefore, the fifth gear is the highest gear and its comprehensive reduction ratio is the smallest. This transmission mode is particularly suitable for vehicles under high-speed cruising conditions, and can give full play to the high-speed performance of the motor 11. At the same time, due to the reduction of transmission links, the transmission efficiency is maximized, which is conducive to improving the economy of the whole vehicle.

[0098] Compared with the prior art, the single-motor five-speed transmission electric drive axle system provided in the embodiment of the present invention only uses two shift actuators and gear sleeves to achieve power transmission of five forward gears. Compared with the solution that requires three or more actuators in the prior art, it not only greatly reduces the system cost and structural complexity, but also improves the reliability and maintenance convenience of the system; at the same time, by setting the third gear as a transition gear between the second gear and the fourth gear, the speed ratio difference between adjacent gears is effectively reduced, and the smaller speed ratio difference can not only shorten the speed synchronization time during the gear shifting process, but also can significantly reduce the gear shifting shock, thereby improving the gear shifting quality and service life of the system.

[0099] In one embodiment of the present invention, a vehicle is provided, which is equipped with the above-mentioned single-motor five-speed transmission electric drive axle system. Preferably, the vehicle in this embodiment is a purely electric commercial vehicle, such as an electric truck, an electric bus, an electric transport vehicle, an electric tractor, etc. Based on the above-mentioned electric drive axle system, the vehicle can meet the driving requirements of different working conditions, wherein the low gear position can meet the needs of frequent starting and stopping and climbing, and the high gear position can achieve economic cruising and improve the cruising range. Under the conditions of slope or load, sufficient power output can be ensured through reasonable gear selection.

[0100] 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 to this. Those of ordinary skill in the art may make various changes and modifications therein 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 required by the appended claims.

[0101] In the description provided herein, a large number of specific details are described. However, it is understood that the embodiments of the present application can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

[0102] Similarly, it should be understood that in order to streamline the present application and help understand 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 method of the present application should not be interpreted as reflecting the following intention: the claimed application requires more features than the features clearly stated in each claim. More specifically, as reflected in the corresponding claims, the inventive point is that the corresponding technical problem can be solved with features less than all the features of a single disclosed embodiment. Therefore, the claims following the specific embodiment are hereby explicitly incorporated into the specific embodiment, wherein each claim itself serves as a separate embodiment of the present application.

[0103] It will be understood by those skilled in the art that, except for mutually exclusive features, all features disclosed in this specification (including the accompanying claims, abstracts and drawings) and all processes or units of any method or device disclosed in this specification may be combined in any combination. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstracts and drawings) may be replaced by an alternative feature that provides the same, equivalent or similar purpose.

Claims

1. A single-motor five-speed transmission electric drive axle system, characterized in that: It includes a motor, a first shift mechanism, a second shift mechanism, a planetary gear assembly and three transmission gear sets; The planetary gear assembly includes a sun gear, planetary gears, a planet carrier and a ring gear, and the sun gear is connected to the three transmission gear sets through a sun gear shaft; The three transmission gear sets include a first driving gear and a first driven gear, a second driving gear and a second driven gear, and a third driven gear; The motor is connected to an input shaft, and the input shaft is meshed with a constantly meshing intermediate shaft; the first driving gear and the second driving gear are sequentially arranged on the constantly meshing intermediate shaft, and the first shifting mechanism is arranged between the first driving gear and the second driving gear; The first driven gear and the second driven gear are fixed on the sun gear shaft, the third driven gear is loosely sleeved on the sun gear shaft, and the second shifting mechanism is arranged between the third driven gear and the planetary gear assembly; Through the cooperation of the first shift mechanism and the second shift mechanism, five transmission gears are formed.

2. The single-motor five-speed transmission electric drive axle system according to claim 1, characterized in that: The first shift mechanism includes a first shift actuator, a first shift fork, a first gear sleeve and a first gear hub; The first gear hub is fixedly arranged on the constant meshing intermediate shaft, and the first gear hub is arranged between the first driving gear and the second driving gear, and the first gear sleeve is sleeved on the first gear hub and can slide axially; The first shift actuator drives the first gear sleeve through the first shift fork, so that the first gear sleeve can be selectively engaged with the first driving gear or the second driving gear.

3. The single-motor five-speed transmission electric drive axle system according to claim 2 is characterized in that: The second shift mechanism includes a second shift actuator, a second shift fork, a second gear sleeve and a second gear hub; The second gear hub is fixedly disposed on the sun gear shaft, and the second gear hub is disposed between the coupling teeth of the third driven gear and the planet carrier, and the second gear sleeve is sleeved on the second gear hub and can slide axially; The second shift actuator drives the second gear sleeve through the second shift fork, so that the second gear sleeve can be selectively engaged with the third driven gear or the planet carrier.

4. The single-motor five-speed transmission electric drive axle system according to claim 1, characterized in that: There is a first reduction ratio between the first driving gear and the first driven gear, there is a second reduction ratio between the second driving gear and the second driven gear, and there is a third reduction ratio between the third driven gear and the meshing gear of the constantly meshing intermediate shaft; The first reduction ratio is greater than the second reduction ratio, and the second reduction ratio is greater than the third reduction ratio.

5. The single-motor five-speed transmission electric drive axle system according to claim 1, characterized in that: The sun gear shaft is fixedly disposed at one end of the sun gear, and a plurality of planetary gears are disposed around the sun gear; The planetary gears are respectively meshed with the sun gear and the ring gear, and the planetary gears are rotatably mounted on the planetary carrier; The ring gear is fixed on the housing of the planetary gear assembly, and the output end of the planetary carrier is connected to the differential.

6. The single-motor five-speed transmission electric drive axle system according to claim 3, characterized in that: When in the first gear transmission state, the first gear sleeve is engaged with the first driving gear, and the second gear sleeve is in the middle position and is not engaged with the third driven gear and the planet carrier.

7. The single-motor five-speed transmission electric drive axle system according to claim 3, characterized in that: When in the second gear transmission state, the first gear sleeve is engaged with the second driving gear, and the second gear sleeve is in a middle position and is not engaged with the third driven gear and the planet carrier.

8. The single-motor five-speed transmission electric drive axle system according to claim 3, characterized in that: When in the third gear transmission state, the first gear sleeve is in a middle position and is not engaged with the first driving gear and the second driving gear, and the second gear sleeve is engaged with the third driven gear.

9. The single-motor five-speed transmission electric drive axle system according to claim 3, characterized in that: When in the fourth gear transmission state, the first gear sleeve is engaged with the first driving gear, and the second gear sleeve is engaged with the planet carrier.

10. The single-motor five-speed transmission electric drive axle system according to claim 3, characterized in that: When in the fifth gear transmission state, the first gear sleeve is engaged with the second driving gear, and the second gear sleeve is engaged with the planet carrier.

11. A vehicle, characterized in that: The vehicle includes a single-motor five-speed transmission electric drive axle system as described in any one of claims 1-10.

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