Coaxial drive apparatus and vehicle

Abstract

The present application provides a coaxial drive apparatus and a vehicle. The coaxial drive apparatus comprises: a housing, a stator, and a rotor, the housing comprising an end cover, and the end cover being provided with a first flow passage; a rotor shaft, a cavity being provided inside of the rotor shaft, the cavity passing through both ends of the rotor shaft, a second hole being provided in the rotor shaft, and the second hole communicating with the cavity and the rotor; and a through shaft, passing through the cavity of the rotor shaft, one end of the through shaft extending to the end cover, a second flow passage being provided in the through shaft, and a third hole and a fourth hole communicating with the second flow passage being provided in the through shaft. After a cooling medium flows out of the first hole, the cooling medium can be buffered in a buffer tank first and then fill the buffer tank, and the pressure of the cooling medium can be easily increased in the buffer tank. According to the solution provided in the present application, even when the through shaft rotates at a high speed and the first hole and the third hole are misaligned, the cooling medium can still flow into the third hole, so that the cooling effect on the rotor is ensured.

Description

Coaxial drive unit and vehicle

[0001] This application claims priority to Chinese Patent Application No. 2024115870152, filed on November 7, 2024, entitled "Coaxial Drive Device and Vehicle", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of vehicle powertrain technology, specifically to a coaxial drive device and a vehicle. Background Technology

[0003] The drive motor is a core component of new energy vehicles, characterized by its compact structure, high power density, and high efficiency. However, motors generate a significant amount of heat during operation, and high temperatures can negatively impact their output performance. Therefore, controlling the motor's temperature rise during operation is a key factor in improving the performance of new energy vehicles.

[0004] In electric vehicle drive systems, coaxial electric drives offer advantages such as high mechanical efficiency and compact structure. However, because the through shaft spans the entire drive mechanism, the rotor oil intake presents certain challenges. Different technologies have been employed to achieve cooling oil intake in coaxial electric drives. One method involves installing oil channels within the through shaft, introducing cooling oil into the shaft through end caps. However, since the through shaft is constantly rotating at high speed, the oil inlet and outlet holes on the through shaft are constantly switching between alignment and misalignment. This results in significant oil intake resistance and fluctuations, ultimately leading to poor rotor cooling. Summary of the Invention

[0005] The technical problem to be solved by this application is to overcome the defects of large fluctuations and high resistance in the through-shaft oil inlet method of coaxial electric drive system in related technologies, thereby providing a coaxial drive device and vehicle.

[0006] To address the aforementioned problems, this application provides a coaxial drive device, comprising: a housing, a stator, and a rotor, both of which are disposed within the housing. The housing includes an end cover with a first flow channel and a first hole communicating with the first flow channel; a rotor shaft rotatably disposed within the housing and fixedly connected to the rotor, the rotor shaft having a cavity extending through both ends of the rotor shaft, and a second hole communicating with the cavity and the rotor; and a through shaft passing through the cavity of the rotor shaft, one end of which extends to the end cover, the through shaft having a second flow channel, and a third hole and a fourth hole communicating with the second flow channel, the third hole communicating with the first hole and the fourth hole communicating with the cavity. At the mating point between the end cover and the through shaft, a buffer groove is provided on the surface of the end cover / or the surface of the through shaft, and both the first hole and the third hole communicate with the buffer groove.

[0007] In one embodiment, the buffer groove is annular and extends circumferentially.

[0008] In one embodiment, the end cap is provided with a pivot hole, one end of the through shaft is inserted into the pivot hole, and a buffer groove is provided on the hole wall of the pivot hole.

[0009] In one embodiment, two sets of sealing structures are provided between the end cap and the through shaft, and the two sets of sealing structures are respectively located on both sides of the buffer groove along the axial direction.

[0010] In one embodiment, there are multiple fourth holes, with at least some of the fourth holes being offset along the axial direction of the through shaft; and / or, at least some of the fourth holes being offset along the circumferential direction of the through shaft.

[0011] In one embodiment, the inner wall of the cavity is provided with a limiting groove, the second hole is provided at the bottom of the limiting groove, and the fourth hole is located within the range of the limiting groove along the axial direction of the through shaft.

[0012] In one embodiment, the limiting groove is annular and extends circumferentially along the rotor shaft.

[0013] In one embodiment, the rotor includes a cooling channel, and the second hole includes a first hole group that communicates with the cooling channel.

[0014] In one embodiment, the second hole further includes a second hole group located on the outside of the rotor, and the first hole group and the second hole group are offset from each other along the axial direction of the rotor shaft.

[0015] In one embodiment, there are multiple third holes (52), and the multiple third holes (52) are evenly distributed along the circumference.

[0016] In one embodiment, the plurality of third holes (52) are located in the same axial position.

[0017] In one embodiment, the third hole (52) and the fourth hole (53) extend radially along the through shaft (50) and communicate with the second flow channel (51) and the outside of the through shaft (50).

[0018] In one embodiment, the rotor shaft (40) and the through shaft (50) are connected by a speed change mechanism.

[0019] This application also provides a vehicle including the aforementioned coaxial drive unit.

[0020] This application has the following advantages:

[0021] Using the technical solution of this application, the cooling medium is introduced from the first flow channel of the end cover, and enters the through shaft through the first and third holes. Then, the cooling medium is introduced to the rotor through the second flow channel, the third hole, and the first hole, thereby cooling the rotor. During the operation of the coaxial drive device, the third hole rotates at high speed relative to the first hole, and switches back and forth between aligned and misaligned states. After the cooling medium flows out of the first hole, it can be buffered in the buffer tank and fill the buffer tank. The cooling medium can easily increase its pressure in the buffer tank. Therefore, even when the through shaft rotates at high speed and the first and third holes are misaligned, the cooling medium can still flow into the third hole, and it can ensure that the cooling medium discharged from the second hole has a high pressure and small pressure fluctuation, thus ensuring the cooling effect on the rotor. This solves the defects of large fluctuation and high resistance in the through shaft oil inlet method of coaxial electric drive systems in related technologies.

[0022] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0023] The above and other objects, features and advantages of this application will become more apparent from the more detailed description of exemplary embodiments thereof in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments thereof.

[0024] Figure 1 shows a schematic diagram of the coaxial drive device of this application;

[0025] Figure 2 shows a cross-sectional schematic diagram of the coaxial drive device in Figure 1;

[0026] Figure 3 shows a schematic diagram of the structure at the end cap location in Figure 2;

[0027] Figure 4 shows a schematic diagram of the structure at the second hole in Figure 2;

[0028] Figure 5 shows a schematic diagram of the end cover of the coaxial drive device in Figure 1;

[0029] Figure 6 shows a cross-sectional view of the end cap in Figure 5;

[0030] Figure 7 shows a schematic diagram of the rotor shaft of the coaxial drive device in Figure 1;

[0031] Figure 8 shows a cross-sectional schematic diagram of the rotor shaft in Figure 7;

[0032] Figure 9 shows a schematic diagram of the through-shaft structure of the coaxial drive device in Figure 1;

[0033] Figure 10 shows a schematic cross-sectional view of the through shaft in Figure 9.

[0034] Explanation of reference numerals in the attached figures:

[0035] 10. Stator; 20. Rotor; 30. End cover; 31. First flow channel; 32. First hole; 33. Shaft hole; 40. Rotor shaft; 41. Cavity; 411. Limiting groove; 42. Second hole; 421. First hole group; 422. Second hole group; 50. Through shaft; 51. Second flow channel; 52. Third hole; 53. Fourth hole; 60. Buffer groove; 70. Sealing structure. Detailed Implementation

[0036] Embodiments of this application will now be described in more detail with reference to the accompanying drawings. While embodiments of this application are shown in the drawings, it should be understood that this application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to make this application more thorough and complete, and to fully convey the scope of this application to those skilled in the art.

[0037] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0038] It should be understood that although the terms "first," "second," "third," etc., may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0039] As shown in Figures 1 to 10, the coaxial drive device provided in this application embodiment includes a housing, a stator 10, a rotor 20, a rotor shaft 40, and a through shaft 50. The stator 10 and rotor 20 are both disposed within the housing, and the housing includes an end cover 30. The end cover 30 has a first flow channel 31 and a first hole 32 communicating with the first flow channel 31. The rotor shaft 40 is rotatably disposed within the housing and fixedly connected to the rotor 20. The rotor shaft 40 has a cavity 41 inside, which extends through both ends of the rotor shaft 40. The rotor shaft 40 has a second hole 42 communicating with both the cavity 41 and the rotor 20. The through shaft 50 passes through the cavity 41 of the rotor shaft 40, and one end of the through shaft 50 extends to the end cover 30. A second flow channel 51 is provided inside the through shaft 50. A third hole 52 and a fourth hole 53 are provided on the through shaft 50, which are connected to the second flow channel 51. The third hole 52 is connected to the first hole 32, and the fourth hole 53 is connected to the cavity 41.

[0040] In one embodiment, at the mating point between the end cap 30 and the through shaft 50, a buffer groove 60 is provided on the surface of the end cap 30 / or the surface of the through shaft 50, and both the first hole 32 and the third hole 52 are connected to the buffer groove 60.

[0041] Using the technical solution of this embodiment, the cooling medium is introduced from the first flow channel 31 of the end cover 30, and enters the through shaft 50 through the first hole 32 and the third hole 52. Then, the cooling medium is introduced to the rotor 20 through the second flow channel 51, the third hole 52, and the first hole 32, thereby cooling the rotor 20. During the operation of the coaxial drive device, the third hole 52 rotates at high speed relative to the first hole 32, and switches back and forth between aligned and misaligned states. After the cooling medium flows out from the first hole 32, it can be buffered in the buffer tank 60 and fill the buffer tank 60. The cooling medium can easily increase the pressure in the buffer tank 60. Therefore, even when the through shaft 50 rotates at high speed and the first hole 32 and the third hole 52 are misaligned, the cooling medium can still flow into the third hole 52, and it can ensure that the cooling medium discharged from the second hole 42 has a high pressure and small pressure fluctuation, thus ensuring the cooling effect on the rotor 20. This solves the defects of large fluctuation and high resistance in the through shaft oil inlet method of the coaxial electric drive system in the related art.

[0042] It should be noted that the cooling medium in this embodiment is cooling lubricating oil. Of course, the cooling medium can also be other liquids, gases, etc.

[0043] The coaxial drive device includes a housing, which is also the outer casing of the motor. The housing includes an end cover 30, which is located at the axial end of the housing. As shown in Figures 5 and 6, the end cover 30 has a roughly umbrella-shaped structure. A first flow channel 31 is provided inside the end cover 30. As shown in Figure 5, the first flow channel 31 forms an inlet on the outer surface of the end cover 30, through which the cooling medium can enter into the first flow channel 31.

[0044] As can be seen from Figure 6, a first hole 32 is provided on the inner side of the end cap 30. The first hole 32 is connected to the first flow channel 31, so the cooling medium can be discharged from the end cap 30 through the first hole 32.

[0045] In one embodiment, a stator 10 and a rotor 20 are disposed within the housing. When energized, the rotor 20 can rotate around its axis, thereby providing driving force. At the same time, the rotor 20 generates a large amount of heat during high-speed rotation, so the rotor 20 needs to be cooled to ensure the performance of the motor.

[0046] As shown in Figure 2, the rotor shaft 40 is housed inside the housing, and the inner hole of the rotor 20 is fitted over the rotor shaft 40, with the rotor shaft 40 and the inner hole of the rotor 20 being fixedly connected. Therefore, when the rotor 20 rotates at high speed, it can drive the rotor shaft 40 to rotate synchronously.

[0047] As shown in Figures 7 and 8, the rotor shaft 40 has an inner cavity that extends through both ends of the rotor shaft 40, thus the rotor shaft 40 has a hollow shaft structure with openings at both ends. A second hole 42 is also provided on the rotor shaft 40, extending through both the interior and exterior of the rotor shaft 40. The inner side of the second hole 42 communicates with the cavity 41, and the outer side communicates with the rotor 20.

[0048] The phrase "the outer side of the second hole 42 is connected to the rotor 20" means that the cooling medium discharged from the second hole 42 can flow to the interior or outer surface of the rotor 20, thereby cooling the rotor 20. This includes the second hole 42 being connected to the cooling channel of the rotor 20, or the second hole 42 being connected to the outer space of the rotor 20.

[0049] As shown in Figure 2, the through shaft 50 passes through the cavity 41 of the rotor shaft 40, and the two are coaxially arranged. Both ends of the through shaft 50 extend out of both ends of the rotor shaft 40, and in the direction shown in Figure 2, the right end of the through shaft 50 extends out of the end cover 30.

[0050] In the actual operation of the coaxial drive device, rotor 20 drives rotor shaft 40 to rotate. Then, as shown on the left side of Figure 2, rotor shaft 40 and through shaft 50 are connected through a speed change mechanism. That is, the rotation of rotor shaft 40 (or rotor 20) is transmitted to through shaft 50 after speed change, meaning that rotor shaft 40 and through shaft 50 rotate asynchronously. The rotation of through shaft 50 is output to the wheels, thereby driving the vehicle.

[0051] In one embodiment, as shown in Figures 9 and 10, a second flow channel 51 is provided inside the through shaft 50. The second flow channel 51 can be located at the central axis of the through shaft 50 and extends along the axial direction of the through shaft 50. The second flow channel 51 penetrates the right end face of the through shaft 50 shown in Figure 2, thereby facilitating machining. A third hole 52 and a fourth hole 53 are also provided on the through shaft 50, wherein both the third hole 52 and the fourth hole 53 extend radially along the through shaft 50 and both connect the second flow channel 51 and the outer side of the through shaft 50. Furthermore, the third hole 52 and the fourth hole 53 are offset circumferentially along the through shaft 50.

[0052] As can be seen from Figure 6, a buffer groove 60 is provided on the inner side of the end cap 30, and the first hole 32 is located in the buffer groove 60, that is, the first hole 32 is connected to the buffer groove 60.

[0053] The relationship between the assembled components is shown in Figures 3 and 4. The third hole 52 is connected to the buffer groove 60, and the fourth hole 53 is connected to the cavity 41.

[0054] Based on the above structure, the flow mode of the cooling medium within the coaxial drive device in this embodiment is described below:

[0055] 1. The cooling medium is introduced into the end cover 30 from the first flow channel 31, and then discharged from the first hole 32 into the buffer tank 60;

[0056] 2. The cooling medium in the buffer tank 60 enters the second flow channel 51 inside the through shaft 50 through the third hole 52;

[0057] 3. The cooling medium enters the cavity 41 through the fourth hole 53;

[0058] 4. The cooling medium is discharged to the rotor 20 through the second hole 42, thereby cooling the rotor 20.

[0059] In the above structure, those skilled in the art will understand that during the rotation of the through shaft 50, the third hole 52 rotates at high speed relative to the first hole 32, and the two switch back and forth between aligned and misaligned states. This will bring about the following two problems:

[0060] 1. During the rotation of the through shaft 50, the cooling medium can smoothly enter the through shaft 50 from the end cover 30 only when the third hole 52 and the first hole 32 are completely aligned. In other states (the third hole 52 and the first hole 32 are partially aligned or completely misaligned), the cooling medium has a large flow resistance, so the flow rate of the cooling medium discharged at the second hole 42 fluctuates greatly.

[0061] 2. Because the diameters of the third hole 52 and the first hole 32 are relatively small, they can only be aligned for a very short time during the rotation of the through shaft 50. At other times, the cooling medium has a large flow resistance. Therefore, overall, the pressure of the cooling medium discharged from the second hole 42 is relatively small, that is, the flow rate is relatively small, and the cooling effect on the rotor 20 is relatively weak.

[0062] To address these two issues, a buffer groove 60 is added in this embodiment. That is, after the cooling medium is discharged from the first hole 32, it first fills the buffer groove 60. Once the buffer groove 60 is full of cooling medium, the pressure of the cooling medium increases, and its flow is stronger. Therefore, regardless of whether the third hole 52 and the first hole 32 are perfectly aligned, partially aligned, or misaligned, the cooling medium can flow smoothly into the third hole 52. Consequently, the flow rate of the cooling medium discharged from the second hole 42 is stable and large, resulting in better cooling of the rotor 20.

[0063] As can be understood by those skilled in the art from the content shown in Figure 3, the buffer groove 60 can be provided on the surface of the end cover 30, or on the surface of the through shaft 50, or the buffer groove 60 can be provided on both the surface of the end cover 30 and the through shaft 50.

[0064] In fact, as long as both the first hole 32 and the third hole 52 are connected to the buffer tank 60, the cooling medium can be stored in the buffer tank 60 before entering the third hole 52.

[0065] As shown in Figures 3 and 6, in the technical solution of this embodiment, the buffer groove 60 is annular and extends circumferentially.

[0066] In one embodiment, the annular buffer groove 60 ensures that the third hole 52 remains within the range of the buffer groove 60 regardless of the angle to which the through shaft 50 is rotated, thereby ensuring that the cooling medium can be pressurized in the buffer groove 60 and then smoothly enter the third hole 52.

[0067] As can also be seen from Figure 9, there are multiple third holes 52, which are evenly distributed circumferentially. This arrangement allows the cooling medium to enter the through shaft 50 through a shorter path after being discharged from the first hole 32, thereby reducing the flow resistance of the cooling medium and increasing the flow rate of the cooling medium discharged from the second hole 42.

[0068] In one embodiment, multiple third holes 52 are located at the same axial position. This arrangement ensures that during the rotation of the through shaft 50, multiple third holes 52 can be within the range of the buffer groove 60, and the buffer groove 60 does not need to have a large width.

[0069] In one embodiment, the third hole 52 can be configured as three, four, five, etc.

[0070] In addition, multiple third holes 52 are evenly distributed along the circumference to ensure that the through shaft 50 has a stable center of mass, thereby preventing large-scale vibration during the high-speed rotation of the through shaft 50.

[0071] As can also be seen from Figure 3, the cross-sectional shape of the buffer groove 60 includes a bottom edge and two side edges, one of which is a straight edge and the other is a beveled edge. In one embodiment, the side of the cross-sectional shape of the buffer groove 60 facing the rotor 20 is a beveled edge, and this beveled edge is inclined towards the rotor 20.

[0072] As shown in Figures 3, 5 and 6, in the technical solution of this embodiment, the end cap 30 is provided with a pivot hole 33, one end of the through shaft 50 is inserted into the pivot hole 33, and the buffer groove 60 is provided on the hole wall of the pivot hole 33.

[0073] In one embodiment, the through shaft 50 passes through the pivot hole 33, thereby passing through the end cap 30. As shown in Figure 6, the pivot hole 33 has multiple stepped surfaces, and the aforementioned buffer groove 60 is disposed on the surface of the pivot hole 33 closest to the through shaft 50, i.e., on the left wall of the pivot hole 33 in Figure 6. This arrangement causes the gap between the through shaft 50 and the pivot hole 33, as well as the buffer groove 60, to form a small chamber. When the cooling medium flows into this chamber, it can quickly fill the chamber, increasing the pressure of the cooling medium and thus increasing the pressure of the cooling medium discharged from the second hole 42.

[0074] As shown in Figures 3 and 6, in the technical solution of this embodiment, two sets of sealing structures 70 are provided between the end cap 30 and the through shaft 50, and the two sets of sealing structures 70 are respectively located on both sides of the buffer groove 60 along the axial direction.

[0075] In one embodiment, the aforementioned closed chamber is formed between the two sets of sealing structures 70, the outer surface of the through shaft 50, the inner surface of the rotating shaft hole 33, and the buffer groove 60. In one embodiment, the sealing structure 70 includes a sealing ring, and an mounting ring groove is provided on the outer surface of the through shaft 50, with the sealing ring disposed within the mounting ring groove. When the through shaft 50 is installed in the rotating shaft hole 33, the sealing ring is compressed and deformed.

[0076] In one embodiment, there are two mounting ring grooves, which are located on both sides of the third hole 52 in the axial direction, and the two mounting ring grooves are used to install two sealing rings respectively.

[0077] As shown in Figure 9, in the technical solution of this embodiment, there are multiple fourth holes 53, and at least some of the fourth holes 53 are offset along the axial direction of the through shaft 50; and / or, at least some of the fourth holes 53 are offset along the circumferential direction of the through shaft 50.

[0078] Since the through shaft 50 transmits a large torque, while opening the fourth hole 53 on the through shaft 50, it is necessary to ensure that the strength of the through shaft 50 meets the requirements.

[0079] In one embodiment, this embodiment provides a plurality of fourth holes 53, thereby increasing the number of channels through which the cooling medium flows out from the through shaft 50. Furthermore, in this embodiment, the plurality of fourth holes 53 are staggered in the axial or circumferential direction to prevent the opening of too many fourth holes 53 at a specific location on the through shaft 50, which could lead to a weaker strength at that location.

[0080] As shown in Figures 9 and 10, the plurality of fourth holes 53 in the embodiment are divided into two groups, and the two groups of fourth holes 53 are staggered in the axial direction of the through shaft 50. Furthermore, each group of fourth holes 53 includes multiple fourth holes 53, with the multiple fourth holes 53 in the same group spaced apart along the circumference of the through shaft 50, and the fourth holes 53 in different groups staggered in the circumference of the through shaft 50. This ensures that there are no areas on the through shaft 50 with a large number of fourth holes 53.

[0081] In some embodiments not shown, the arrangement of the multiple fourth holes 53 can be determined by those skilled in the art according to actual needs. The key is to ensure that there are no areas on the through shaft 50 with a large number of fourth holes 53, and that the center of gravity of the through shaft 50 is stable.

[0082] As shown in Figures 4 and 8, in the technical solution of this embodiment, the inner wall of the cavity 41 is provided with a limiting groove 411, the second hole 42 is provided at the bottom of the limiting groove 411, and the fourth hole 53 is located within the range of the limiting groove 411 along the axial direction of the through shaft 50.

[0083] In one embodiment, during the rotation of the through shaft 50, the cooling medium is thrown from the fourth hole 53 onto the inner wall of the cavity 41. The function of the limiting groove 411 is to limit the cooling medium within the area enclosed by the limiting groove 411, that is, to limit the cooling medium to a position near the second hole 42. This reduces the amount of cooling medium adhering to the wall surface farther from the second hole 42, thereby reducing the loss of cooling medium and improving the cooling efficiency of the multi-rotor 20.

[0084] As shown in Figures 4 and 8, the limiting groove 411 is annular and extends circumferentially along the rotor shaft 40. This arrangement allows the limiting groove 411 to confine the cooling medium to a position near the second hole 42 throughout the entire circumferential direction.

[0085] As shown in Figures 4 and 8, in the technical solution of this embodiment, the rotor 20 includes a cooling channel, and the second hole 42 includes a first hole group 421, which is connected to the cooling channel.

[0086] In one embodiment, the cooling medium ejected from the first hole group 421 can enter the cooling channel inside the rotor 20, thereby achieving cooling and temperature reduction of the inside of the rotor 20.

[0087] As shown in Figures 4 and 8, in the technical solution of this embodiment, the second hole 42 further includes a second hole group 422, which is located on the outside of the rotor 20. The first hole group 421 and the second hole group 422 are offset along the axial direction of the rotor shaft 40.

[0088] In one embodiment, the cooling medium ejected from the second hole group 422 can be ejected onto the outer surface of the rotor 20, which can cool the windings on the rotor 20.

[0089] In one embodiment, the first hole group 421 includes a plurality of second holes 42, which are spaced apart circumferentially along the rotor shaft 40.

[0090] In one embodiment, the second hole group 422 includes a plurality of second holes 42, which are spaced apart circumferentially along the rotor shaft 40.

[0091] This application also provides a vehicle, which, according to embodiments of this application, includes the coaxial drive device described above.

[0092] In one implementation, the vehicle can be a new energy electric vehicle.

[0093] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A coaxial drive device, characterized in that, include: The housing, stator (10) and rotor (20) are both disposed in the housing. The housing includes an end cover (30), a first flow channel (31) is provided on the end cover (30), and a first hole (32) communicating with the first flow channel (31) is provided on the end cover (30). A rotor shaft (40) is rotatably disposed inside the housing and fixedly connected to the rotor (20). The rotor shaft (40) has a cavity (41) inside, which passes through both ends of the rotor shaft (40). A second hole (42) is provided on the rotor shaft (40), which communicates with the cavity (41) and the rotor (20). A through shaft (50) is inserted into the cavity (41) of the rotor shaft (40), and one end of the through shaft (50) extends to the end cap (30). A second flow channel (51) is provided inside the through shaft (50). A third hole (52) and a fourth hole (53) communicating with the second flow channel (51) are provided on the through shaft (50). The third hole (52) communicates with the first hole (32), and the fourth hole (53) communicates with the cavity (41). Wherein, at the mating point between the end cap (30) and the through shaft (50), a buffer groove (60) is provided on the surface of the end cap (30) or the surface of the through shaft (50), and the first hole (32) and the third hole (52) are both connected to the buffer groove (60).

2. The coaxial drive device according to claim 1, characterized in that, The buffer groove (60) is annular and extends circumferentially.

3. The coaxial drive device according to claim 1 or 2, characterized in that, The end cap (30) is provided with a pivot hole (33), one end of the through shaft (50) is inserted into the pivot hole (33), and the buffer groove (60) is provided on the hole wall of the pivot hole (33).

4. The coaxial drive device according to claim 3, characterized in that, Two sets of sealing structures (70) are provided between the end cap (30) and the through shaft (50), and the two sets of sealing structures (70) are respectively located on both sides of the buffer groove (60) along the axial direction.

5. The coaxial drive device according to claim 1 or 2, characterized in that, There are multiple fourth holes (53), and at least some of the fourth holes (53) are offset along the axial direction of the through shaft (50); and / or, at least some of the fourth holes (53) are offset along the circumferential direction of the through shaft (50).

6. The coaxial drive device according to claim 1 or 2, characterized in that, The inner wall of the cavity (41) is provided with a limiting groove (411), the second hole (42) is provided at the bottom of the limiting groove (411), and the fourth hole (53) is located within the range of the limiting groove (411) along the axial direction of the through shaft (50).

7. The coaxial drive device according to claim 6, characterized in that, The limiting groove (411) is annular and extends circumferentially along the rotor shaft (40).

8. The coaxial drive device according to claim 1 or 2, characterized in that, The rotor (20) includes a cooling channel, and the second hole (42) includes a first hole group (421) which is connected to the cooling channel.

9. The coaxial drive device according to claim 8, characterized in that, The second hole (42) also includes a second hole group (422), which is located on the outside of the rotor (20), and the first hole group (421) and the second hole group (422) are offset along the axial direction of the rotor shaft (40).

10. The coaxial drive device according to claim 1 or 2, characterized in that, There are multiple third holes (52), and the multiple third holes (52) are evenly distributed along the circumference.

11. The coaxial drive device according to claim 10, characterized in that, The plurality of third holes (52) are located in the same axial position.

12. The coaxial drive device according to claim 1 or 2, characterized in that, The third hole (52) and the fourth hole (53) extend radially along the through shaft (50) and connect the second flow channel (51) and the outside of the through shaft (50).

13. The coaxial drive device according to claim 1 or 2, characterized in that, The rotor shaft (40) and the through shaft (50) are connected by a speed change mechanism.

14. A vehicle, characterized in that, The coaxial drive device includes any one of claims 1 to 13.

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