Coaxial electric driving system and electric automobile

Abstract

The invention discloses a coaxial type electric driving system and an electric automobile, and relates to the technical field of electric automobiles, the coaxial type electric driving system comprises a driving part, a speed reducer assembly and a differential mechanism assembly, the driving part comprises a driving shaft and a driving part driving the driving shaft to rotate, the driving shaft is arranged in a hollow mode, and the speed reducer assembly is arranged in the driving part; the speed reducer assembly comprises a speed reducer input gear, a speed reducer output gear and an intermediate gear assembly, the differential mechanism assembly comprises a differential mechanism body, a differential mechanism input gear, a first half shaft and a second half shaft, the differential mechanism input gear is externally meshed with the speed reducer output gear and arranged on the driving shaft in a sleeving mode, and the first half shaft and the second half shaft are coaxially arranged; the first half shaft partially extends into the driving shaft and is coaxial with the driving shaft, so that the driving shaft, the speed reducer input gear, the first half shaft, the second half shaft and the differential mechanism input gear are all located on the same axis. According to the invention, a plurality of assemblies are coaxially arranged, so that the overall dimension is smaller, and the structure is more compact.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicles, and in particular to a coaxial electric drive system and an electric vehicle. Background Art

[0002] With the continuous advancement of science and technology, people pay more and more attention to environmental protection. New energy vehicles have become a hot spot for development, especially the development of electric vehicles, which has become the focus of development in the field of new energy. In order to meet consumer demand, major manufacturers continue to improve the power and driving performance of vehicles, and the power density requirements of electric drive systems are also increasing.

[0003] Due to the increase in power and torque requirements, existing electric drive systems use a three-axis reducer or a planetary coaxial reducer layout. However, these two layouts have large dimensions and high costs, resulting in a complex and bloated structure, serious transmission energy loss, and an inability to guarantee transmission accuracy. They cannot meet the vehicle's mounting requirements and need to be optimized in structure. Summary of the invention

[0004] The main purpose of the present invention is to provide a coaxial electric drive system and an electric vehicle, aiming to solve the problems of large external dimensions and high manufacturing cost of the existing electric drive system.

[0005] To achieve the above object, the present invention provides a coaxial electric drive system, comprising:

[0006] A driving part, comprising a driving shaft and a driving member for driving the driving shaft to rotate, wherein the driving shaft is hollow;

[0007] A reducer assembly, comprising a reducer input gear, a reducer output gear and an intermediate gear assembly, wherein the reducer input gear is drivingly mounted on the drive shaft, and the reducer output gear is drivingly connected to the reducer input gear through the intermediate gear assembly; and,

[0008] A differential assembly includes a differential body, a differential input gear, a first half shaft and a second half shaft, wherein the differential input gear is externally meshed with the reducer output gear and sleeved on the drive shaft, the first half shaft and the second half shaft are coaxially arranged and both are drivingly connected to the differential body to rotate under the drive of the differential body, the first half shaft partially extends into the interior of the drive shaft and is coaxially arranged with the drive shaft, so that the drive shaft, the reducer input gear, the first half shaft, the second half shaft and the differential input gear are all located on the same axis.

[0009] In one embodiment, the coaxial electric drive system further comprises an intermediate plate housing sleeved on the drive shaft, the intermediate plate housing is located between the reducer input gear and the differential input gear, and the differential input gear is sleeved on the outside of the intermediate plate housing.

[0010] In one embodiment, a first bearing is disposed between the intermediate plate housing and the drive shaft, and a second bearing is disposed between the differential input gear and the intermediate plate housing.

[0011] In one embodiment, a radial dimension of the intermediate plate housing at a location where the first bearing is installed is greater than a radial dimension of the intermediate plate housing at a location where the second bearing is installed.

[0012] In one embodiment, the radial dimension of the drive shaft at the installation location of the first bearing is smaller than the radial dimension of the drive shaft at the installation location of the reducer input gear.

[0013] In one embodiment, at least one oil seal is disposed between the drive shaft and the intermediate plate housing.

[0014] In one embodiment, the driving member includes a motor housing, a stator fixedly disposed in the motor housing, and a rotor rotatably installed in the motor housing. The rotor is sleeved on the driving shaft to drive the driving shaft to rotate, and the rotor is spaced apart from the reducer input gear.

[0015] In one embodiment, a third bearing is provided between the rotor and the reducer input gear.

[0016] In one embodiment, the intermediate gear assembly includes an intermediate shaft and a secondary transmission gear sleeved on one end of the intermediate shaft, the intermediate shaft is arranged on one side of the drive shaft in the radial direction, and the other end is connected to the reducer output gear, and the secondary transmission gear is meshed with the reducer input gear.

[0017] The present invention further provides an electric vehicle, comprising the above-mentioned coaxial electric drive system, wherein the coaxial electric drive system comprises:

[0018] A driving part, comprising a driving shaft and a driving member for driving the driving shaft to rotate, wherein the driving shaft is hollow;

[0019] A reducer assembly, comprising a reducer input gear, a reducer output gear and an intermediate gear assembly, wherein the reducer input gear is drivingly mounted on the drive shaft, and the reducer output gear is drivingly connected to the reducer input gear through the intermediate gear assembly; and,

[0020] A differential assembly includes a differential body, a differential input gear, a first half shaft and a second half shaft, wherein the differential input gear is externally meshed with the reducer output gear and sleeved on the drive shaft, the first half shaft and the second half shaft are coaxially arranged and both are drivingly connected to the differential body to rotate under the drive of the differential body, the first half shaft partially extends into the interior of the drive shaft and is coaxially arranged with the drive shaft, so that the drive shaft, the reducer input gear, the first half shaft, the second half shaft and the differential input gear are all located on the same axis.

[0021] The technical solution of the present invention is to set the drive shaft as a hollow structure, and extend the first half-shaft into the interior of the drive shaft so that it passes through the drive shaft and is connected to the wheel hub, so that the overall structure is simple and compact, and the stability of the system is improved while simplifying the complexity of the system. Further, by setting the drive shaft, the reducer input gear, the first half-shaft, the second half-shaft and the differential input gear coaxially, the reducer input gear and the differential input gear can be coaxially processed and formed as a whole, ensuring the coaxiality of the installation of the two gears, making the installation accuracy higher, thereby improving the transmission accuracy. Furthermore, by setting the meshing form of the differential input gear and the reducer output gear to external meshing, the radial size of the overall structure of the system is reduced, the compactness of the system is further improved, the manufacturing process is better, the cost is lower, and the mounting performance requirements of the whole vehicle are met. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0023] Figure 1 A schematic structural diagram of an embodiment of a coaxial electric drive system provided by the present invention.

[0024] Description of Figure Numbers:

[0025] 1000. Coaxial electric drive system; 1. Drive unit; 11. Drive shaft; 12. Drive member; 121. Rotor; 2. Reducer assembly; 21. Reducer input gear; 22. Reducer output gear; 23. Intermediate gear assembly; 231. Intermediate shaft; 232. Secondary transmission gear; 3. Differential assembly; 31. Differential body; 32. Differential input gear; 33. First half shaft; 34. Second half shaft; 4. Intermediate plate housing; 5. First bearing; 6. Second bearing; 7. Third bearing.

[0026] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the 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.

[0028] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0029] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0030] With the continuous advancement of science and technology, people pay more and more attention to environmental protection. New energy vehicles have become a hot spot for development, especially the development of electric vehicles, which has become the focus of development in the field of new energy. In order to meet consumer demand, major manufacturers continue to improve the power and driving performance of vehicles, and the power density requirements of electric drive systems are also increasing.

[0031] Due to the increase in power and torque requirements, existing electric drive systems use a three-axis reducer or a planetary coaxial reducer layout. However, these two layouts have large dimensions and high costs, resulting in a complex and bloated structure, serious transmission energy loss, and an inability to guarantee transmission accuracy. They cannot meet the vehicle's mounting requirements and need to be optimized in structure.

[0032] The main purpose of the present invention is to provide a coaxial electric drive system and an electric vehicle, aiming to solve the problems of large external dimensions and high manufacturing cost of the existing electric drive system.

[0033] See also Figure 1 The present invention proposes a coaxial electric drive system 1000, comprising a drive unit 1, a reducer assembly 2 and a differential assembly 3, wherein the drive unit 1 comprises a drive shaft 11 and a drive member 12 for driving the drive shaft 11 to rotate, wherein the drive shaft 11 is hollow, the reducer assembly 2 comprises a reducer input gear 21, a reducer output gear 22 and an intermediate gear assembly 23, wherein the reducer input gear 21 is driven and installed on the drive shaft 11, and the reducer output gear 22 is transmission-connected to the reducer input gear 21 through the intermediate gear assembly 23, and the differential assembly 3 comprises a differential body 31, A differential input gear 32, a first half shaft 33 and a second half shaft 34, wherein the differential input gear 32 is externally meshed with the reducer output gear 22 and is sleeved on the drive shaft 11, the first half shaft 33 and the second half shaft 34 are coaxially arranged and are both drivingly connected to the differential body 31 to rotate under the drive of the differential body 31, the first half shaft 33 partially extends into the drive shaft 11 and is coaxially arranged with the drive shaft 11, so that the drive shaft 11, the reducer input gear 21, the first half shaft 33, the second half shaft 34 and the differential input gear 32 are all located on the same axis.

[0034] The technical solution of the present invention is to set the drive shaft 11 as a hollow structure, and extend the first half shaft 33 into the interior of the drive shaft 11 so that it passes through the drive shaft 11 and is connected to the wheel hub, so that the overall structure is simple and compact, and the system stability is improved while simplifying the complexity of the system. Further, by setting the drive shaft 11, the reducer input gear 21, the first half shaft 33, the second half shaft 34 and the differential input gear 32 coaxially, the reducer input gear 21 and the differential input gear 32 can be coaxially processed and formed integrally, ensuring the coaxiality of the installation of the two gears, making the installation accuracy higher, thereby improving the transmission accuracy. Furthermore, by setting the meshing form of the differential input gear 32 and the reducer output gear 22 to external meshing, the radial size of the overall structure of the system is reduced, the compactness of the system is further improved, the manufacturing process is better, the cost is lower, and the mounting performance requirements of the whole vehicle are met.

[0035] It can be understood that the specific structure of the intermediate gear assembly 23 can be adjusted accordingly according to the different functions described in different electric drive systems. On this basis, all components except the intermediate gear assembly 23 are coaxially arranged, which can maximize the compactness of the overall structure of the system.

[0036] It should be emphasized that internal meshing and external meshing are two types of meshing modes between gears. In the prior art, in order to increase the transmission ratio, the output gear 22 of the reducer and the input gear 32 of the differential are usually internally meshed for transmission. Such a design results in a larger radial size of the electric drive system, and is not convenient for the combination of the differential input gear 32 and the differential body 31. More support members need to be set to ensure the stability of the system, thereby increasing the manufacturing cost. The present invention adopts an external meshing method, which not only shortens the radial size of the electric drive system, but also improves the compactness of the system, facilitates the subsequent setting of support members between the differential input gear 32 and the drive shaft 11, and has better manufacturing processability.

[0037] Furthermore, the coaxial electric drive system 1000 further includes an intermediate plate housing 4 sleeved on the drive shaft 11, the intermediate plate housing 4 is located between the reducer input gear 21 and the differential input gear 32, and the differential input gear 32 is sleeved on the outside of the intermediate plate housing 4. By providing the intermediate plate housing 4, the differential input gear 32 can be better installed in cooperation with the drive shaft 11, thereby improving the stability of the coaxial electric drive system 1000. It is worth mentioning that the intermediate plate housing 4 is coaxially arranged with the drive shaft 11, that is, the drive shaft 11, the reducer input gear 21, the first half shaft 33, the second half shaft 34, the differential input gear 32 and the intermediate plate housing 4 are all located on the same axis, thereby ensuring the consistency of each component of the system and the position of each component.

[0038] It should be noted that the present invention does not limit the specific implementation form of the intermediate plate housing 4. In a preferred embodiment, the cross-section of the intermediate plate housing 4 is set to be "L"-shaped, and the differential input gear 32 is set on the right-angled inner side of the "L"-shaped plate, thereby positioning the differential input gear 32 and isolating the differential from the driving member 12.

[0039] In another embodiment of the present invention, the cross-section of the intermediate plate shell 4 is set to be "T"-shaped. With this design, the "T"-shaped plate has two right-angle bends, which is convenient for the subsequent installation of bearings and other supporting parts, but the manufacturing process is more complicated than the preferred embodiment.

[0040] Furthermore, a first bearing 5 is provided between the intermediate plate housing 4 and the drive shaft 11, and a second bearing 6 is provided between the differential input gear 32 and the intermediate plate housing 4. With such a design, the installation of the differential input gear 32 and the intermediate plate housing 4 is realized through two bearings, which improves the compactness of the system, and avoids direct contact between the differential input gear 32, the intermediate plate housing 4 and the drive shaft 11, reduces wear, and improves the life of the system. It is worth mentioning that the inner ring of the second bearing 6 is fixedly connected with the drive shaft 11, and the outer ring is loosely matched with the intermediate plate housing 4, and the inner ring of the first bearing 5 is loosely matched with the intermediate plate housing 4, and the outer ring is fixedly connected with the differential input gear 32. Such a configuration ensures that the drive shaft 11 and the differential input gear 32 can rotate relative to the intermediate plate housing 4, and are independently arranged without interference with each other.

[0041] In order to improve the stability of the system, specifically, the radial dimension of the intermediate plate housing 4 at the installation location of the first bearing 5 is larger than the radial dimension at the installation location of the second bearing 6. With such a design, the size of the side of the intermediate plate housing 4 close to the driving member 12 is larger, which can limit the first bearing 5 installed on the other side. At the same time, since the other side needs to accommodate the bearing, the radial dimension space requirement is larger. By setting the radial dimension of this side smaller, the installation space is released, which is convenient for the assembly of the second bearing 6, and is more reasonable in terms of process.

[0042] Specifically, the radial dimension of the drive shaft 11 at the installation location of the first bearing 5 is smaller than the radial dimension of the installation location of the reducer input gear 21. In such a design, since the radial dimension of the side of the intermediate plate housing 4 close to the driving member 12 is larger, the radial dimension of the drive shaft 11 at the installation location of the first bearing 5 is relatively reduced, thereby releasing the installation space, facilitating the assembly of the first bearing 5, and being more reasonable in terms of process.

[0043] It is worth mentioning that the above-mentioned specific restrictions on the radial dimensions can be set one by one or simultaneously. In a preferred embodiment of the present invention, the simultaneous setting method is adopted.

[0044] In one embodiment of the present invention, at least one oil seal is provided between the drive shaft 11 and the intermediate plate housing 4. This arrangement can prevent the oil in the intermediate gear assembly 23 from flowing out of the differential body 31 through the drive shaft 11 and the first half shaft 33. It can be understood that in this embodiment, the radial dimension of the drive shaft 11 at the installation location of the first bearing 5 can be limited to be smaller than the radial dimension at the installation location of the reducer input gear 21, so that the oil seal is positioned through the step surface, which facilitates the installation of the oil seal.

[0045] In one embodiment of the present invention, the driving member 12 includes a motor housing, a stator fixedly disposed in the motor housing, and a rotor 121 rotatably mounted in the motor housing, the rotor 121 is sleeved on the drive shaft 11 to drive the drive shaft 11 to rotate, and the rotor 121 is spaced apart from the reducer input gear 21. With such a configuration, the structure is simpler and the cost is lower. It is understandable that the present invention does not limit the specific connection form between the rotor 121 and the drive shaft 11. In a preferred embodiment of the present invention, the rotor 121 is key-connected to the drive shaft 11. With such a configuration, it is easy to assemble and disassemble and is convenient for maintenance. In another embodiment, the driving member 12 is configured as a frameless torque motor, and the rotor 121 is connected to the drive shaft 11 by electromagnetic force to ensure the synchronous rotation of the rotor 121 and the drive shaft 11 and reduce losses.

[0046] Furthermore, a third bearing 7 is provided between the rotor 121 and the reducer input gear 21. By providing the third bearing 7, the third bearing 7 is mainly supported in the axial direction, and is used to bear the axial force of the rotor 121 and the reducer input gear 21, so that the overall structure of the system is more stable. Furthermore, by arranging the third bearing 7 between the rotor 121 and the reducer input gear 21, the driving shaft 11 is subjected to a more uniform force, thereby improving the service life of the driving shaft 11.

[0047] It is understandable that, in order to prevent the bearing pressure of the third bearing 7 from being too large, a fourth bearing may be provided on the side of the rotor 121 away from the reducer input gear 21, and a fifth bearing may be provided on the side of the reducer input gear 21 away from the rotor 121, so as to bear the axial force of the rotor 121 and the reducer input gear 21 together with the third bearing 7. It is worth mentioning that the fifth bearing may be replaced by the first bearing 5 in the above embodiment.

[0048] It is worth mentioning that in order to ensure that the third bearing 7 as the main support has sufficient bearing capacity, the third bearing 7 is set as a ball bearing. Since the ball bearing is provided with a ball between the inner steel ring and the outer steel ring, the ball bearing can withstand a larger load.

[0049] In one embodiment of the present invention, please refer to Figure 1The intermediate gear assembly 23 includes an intermediate shaft 231 and a secondary transmission gear 232 sleeved on one end of the intermediate shaft 231. The intermediate shaft 231 is arranged on one side of the drive shaft 11 in the radial direction, and the other end is connected to the reducer output gear 22. The secondary transmission gear 232 is meshed with the reducer input gear 21. With such a design, the transmission of the motor torque and the speed reduction can be achieved through two pairs of gears, the structure is simple, the radial size is small, and the compactness of the system is improved.

[0050] It can be understood that the diameter of the secondary transmission gear 232 is greater than the diameter of the reducer input gear 21, and the diameter of the reducer output gear 22 is smaller than the diameter of the differential input gear 32, which ensures that the reducer assembly 2 has a higher transmission ratio. Of course, the present invention does not limit the specific implementation form of the intermediate gear assembly 23. In the preferred embodiment of the present invention, the above-mentioned secondary transmission structure is adopted, which is compact and simple in structure. In another embodiment, the intermediate gear assembly 23 adopts the arrangement form of a planetary gear set, which has a larger transmission ratio and higher power, but a higher manufacturing cost and worse processability.

[0051] The present invention also proposes an electric vehicle, which includes the above-mentioned coaxial electric drive system 1000. Since the electric vehicle includes the coaxial electric drive system 1000, the specific structure of the coaxial electric drive system 1000 refers to the above-mentioned embodiment. Since the coaxial electric drive system 1000 of the electric vehicle adopts all the technical solutions of all the above-mentioned embodiments, it at least has all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here.

[0052] The above description is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A coaxial electric drive system, characterized in that: include: A driving part, comprising a driving shaft and a driving member for driving the driving shaft to rotate, wherein the driving shaft is hollow; A reducer assembly, comprising a reducer input gear, a reducer output gear and an intermediate gear assembly, wherein the reducer input gear is drivingly mounted on the drive shaft, and the reducer output gear is drivingly connected to the reducer input gear through the intermediate gear assembly; as well as, A differential assembly includes a differential body, a differential input gear, a first half shaft and a second half shaft, wherein the differential input gear is externally meshed with the reducer output gear and sleeved on the drive shaft, the first half shaft and the second half shaft are coaxially arranged and both are drivingly connected to the differential body to rotate under the drive of the differential body, the first half shaft partially extends into the interior of the drive shaft and is coaxially arranged with the drive shaft, so that the drive shaft, the reducer input gear, the first half shaft, the second half shaft and the differential input gear are all located on the same axis.

2. The coaxial electric drive system according to claim 1, characterized in that: The coaxial electric drive system further comprises an intermediate plate housing sleeved on the drive shaft, wherein the intermediate plate housing is located between the reducer input gear and the differential input gear, and the differential input gear is sleeved on the outer side of the intermediate plate housing.

3. The coaxial electric drive system according to claim 2, characterized in that: A first bearing is disposed between the intermediate plate housing and the drive shaft, and a second bearing is disposed between the differential input gear and the intermediate plate housing.

4. The coaxial electric drive system according to claim 3, characterized in that: The radial dimension of the intermediate plate housing at the installation location of the first bearing is larger than the radial dimension of the intermediate plate housing at the installation location of the second bearing.

5. The coaxial electric drive system according to claim 3, characterized in that: The radial dimension of the drive shaft at the installation location of the first bearing is smaller than the radial dimension of the drive shaft at the installation location of the reducer input gear.

6. The coaxial electric drive system according to claim 2, characterized in that: At least one oil seal is disposed between the drive shaft and the intermediate plate housing.

7. The coaxial electric drive system according to claim 1, characterized in that: The driving member includes a motor housing, a stator fixedly arranged in the motor housing, and a rotor rotatably installed in the motor housing. The rotor is sleeved on the driving shaft to drive the driving shaft to rotate. The rotor is spaced apart from the reducer input gear.

8. The coaxial electric drive system according to claim 7, characterized in that: A third bearing is provided between the rotor and the reducer input gear.

9. The coaxial electric drive system according to claim 1, characterized in that: The intermediate gear assembly includes an intermediate shaft and a secondary transmission gear sleeved on one end of the intermediate shaft. The intermediate shaft is arranged on one side of the drive shaft in the radial direction, and the other end is connected to the reducer output gear. The secondary transmission gear is meshed with the reducer input gear.

10. An electric vehicle, characterized in that: A coaxial electric drive system comprising any one of claims 1 to 9.

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