Coaxial electric drive system

Abstract

The utility model relates to the technical field of electric driving, and provides a coaxial electric driving system which comprises a motor shaft and an output shaft coaxially penetrating through the motor shaft, and the first end of the output shaft and the first end of the motor shaft are respectively and rotatably supported by bearings; the oil input channel leads to the output shaft and the first end of the motor shaft, and the bearing channel and the shaft channel are communicated with the oil input channel. The bearing channel is at least formed by a first sealing structure, and the first sealing structure is arranged between the bearing and the oil liquid input channel; the shaft channel is formed between the output shaft and the motor shaft, and a second sealing structure in clearance fit with the output shaft or the motor shaft is arranged at the end, away from the oil input channel, of the shaft channel. According to the utility model, the oil is reasonably distributed through the bearing channel formed by at least the first sealing structure, and the leakage of the oil after entering the gap between the output shaft and the motor shaft is reduced through the second sealing structure arranged in the shaft channel, so that the effective lubrication and cooling of the output shaft, the motor shaft, the bearing and other parts are realized.

Description

Technical Field

[0001] The utility model relates to the technical field of electric drive, in particular to a coaxial electric drive system. Background Art

[0002] The coaxial electric drive system can save layout space, and the output shaft of the electric drive system is coaxially arranged in the hollow motor shaft. At present, there are problems with the lubrication and cooling of related components in the coaxial electric drive system, which are mainly manifested in:

[0003] The output shaft, motor shaft, bearings and other components all need lubrication and cooling, but there is no reasonable distribution plan for the oil;

[0004] Since there is a certain gap between the motor shaft and the output shaft to avoid friction, the oil is prone to leak after entering the gap between the output shaft and the motor shaft.

[0005] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present invention, and therefore may include information that does not constitute prior art known to ordinary technicians in the field. Utility Model Content

[0006] In view of this, the utility model provides a coaxial electric drive system, which can reasonably distribute oil, help to effectively lubricate and cool components such as the output shaft, motor shaft and bearings, and can reduce the leakage of oil after entering the gap between the output shaft and the motor shaft, thereby ensuring effective lubrication and cooling of components such as the output shaft, motor shaft and bearings.

[0007] According to one aspect of the utility model, a coaxial electric drive system is provided, comprising a hollow motor shaft and an output shaft drivingly connected to the motor shaft, the output shaft coaxially passing through and extending out of the motor shaft, the first ends of the output shaft and the motor shaft being rotatably supported by bearings respectively; wherein the coaxial electric drive system is provided with an oil input channel leading to the output shaft and the first end of the motor shaft, and a bearing channel and a shaft channel connected to the oil input channel; the bearing channel leads to the bearing, a first sealing structure is provided between the bearing and the oil input channel, and the bearing channel is formed at least by the first sealing structure; the output shaft is spaced from the motor shaft to form the shaft channel, and the end of the shaft channel away from the oil input channel is provided with a second sealing structure which is gap-matched with the output shaft or the motor shaft.

[0008] In some embodiments, the first sealing structure is a seal, which is in sealing contact with one of the outer ring and the inner ring of the bearing and is clearance-matched with the other to form the bearing channel.

[0009] In some embodiments, the seal is in sealing contact with the outer ring and has a clearance fit with the inner ring.

[0010] In some embodiments, the first sealing structure is a bushing, which is connected to the housing of the coaxial electric drive system and is spaced apart from the output shaft and the first end of the motor shaft to form a gap channel, and the bearing channel includes the gap channel.

[0011] In some embodiments, sealing rings are respectively embedded in the surfaces of the bushing facing the output shaft and the first end of the motor shaft; the sealing rings are movably embedded in the surface of the bushing, and the sealing rings can block and at least partially make way for the gap channel, or the sealing rings are gap-matched with the output shaft and the first end of the motor shaft to at least partially expose the gap channel.

[0012] In some embodiments, the sealing ring is provided with an oil groove connecting the oil input channel and the bearing, and the bearing channel includes the oil groove.

[0013] In some embodiments, the bushing is provided with a through hole communicating with the oil input channel and the shaft channel.

[0014] In some embodiments, the oil input channel is arranged in the housing, and the bushing is also provided with: an oil storage chamber connected to the oil input channel, arranged on the surface of the bushing facing the oil input channel; an oil injection groove connected to the oil storage chamber and the bearing, and the bearing channel includes the oil injection groove.

[0015] In some embodiments, the two ends of the bushing are respectively connected to the housing and cooperate with the output shaft and the first end of the motor shaft, and the middle part of the bushing is recessed to form the annular oil storage chamber; the through hole passes through the oil storage chamber, and the oil injection groove is arranged on the surface where the bushing is connected to the housing.

[0016] In some embodiments, the bushing is made of steel.

[0017] In some embodiments, the oil input channel is disposed in the housing, and an oil drain groove connecting the oil input channel and the bearing is also disposed in the housing, and the bearing channel includes the oil drain groove.

[0018] In some embodiments, the second sealing structure is in sealing contact with the motor shaft and has a clearance fit with the output shaft.

[0019] In some embodiments, the motor of the coaxial electric drive system is arranged horizontally; under the motor operating condition, the oil in the shaft channel is at least partially blocked by the second sealing structure under the action of centrifugal force; under the boost charging condition, the oil in the shaft channel is at least partially blocked by the second sealing structure under the action of gravity.

[0020] In some embodiments, the second sealing structure is a second oil seal; or, the second sealing structure is a boss integrally formed on the inner wall of the motor shaft.

[0021] In some embodiments, the second oil seal includes a rigid frame connected to the motor shaft and a flexible support leg cooperating with the output shaft.

[0022] In some embodiments, the coaxial electric drive system is further provided with a rotor channel connected to the shaft channel, and the rotor channel passes through the motor shaft and the rotor sleeved outside the motor shaft.

[0023] Compared with the prior art, the beneficial effects of the present invention include at least:

[0024] By means of the bearing channel formed by at least the first sealing structure, the oil is reasonably distributed so that part of the oil enters the bearing through the bearing channel to lubricate and cool the bearing, thereby avoiding leakage of most of the oil from the bearing and allowing enough oil to enter the shaft channel to lubricate and cool the output shaft and the motor shaft; the gap size of the bearing channel can be adjusted as needed to adjust the amount of oil entering the bearing, and then adjust the amount of oil entering the shaft channel.

[0025] By setting a second sealing structure in the shaft channel, the leakage of oil in the shaft channel can be effectively blocked, ensuring that the oil can effectively lubricate and cool the output shaft, motor shaft, bearings and other components; the second sealing structure is matched with the output shaft or the motor shaft to reduce the friction loss between the output shaft and the motor shaft, ensuring that the motor shaft and the output shaft can both operate stably when the motor is running; the size of the gap between the second sealing structure and the output shaft / motor shaft can be adjusted as needed to take into account the second sealing structure to block most of the oil leakage in the shaft channel while minimizing the friction loss between the output shaft and the motor shaft.

[0026] The coaxial electric drive system of the utility model has a simple overall design, does not occupy an axial space alone, and can achieve effective lubrication and cooling of components such as the output shaft, the motor shaft, and the bearings.

[0027] It should be understood that the above general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings herein are incorporated into the specification and constitute a part of the specification, showing embodiments consistent with the present utility model, and together with the specification, are used to explain the principles of the present utility model. Obviously, the accompanying drawings described below are only some embodiments of the present utility model, and for ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without creative work.

[0029] Figure 1 A schematic structural diagram of a coaxial electric drive system in an embodiment of the utility model is shown;

[0030] Figure 2 Show Figure 1 An enlarged schematic diagram of a first sealing structure of a coaxial electric drive system shown;

[0031] Figure 3 Show Figure 1 An enlarged schematic diagram of a second sealing structure of the coaxial electric drive system shown;

[0032] Figure 4 A schematic structural diagram of another coaxial electric drive system in an embodiment of the utility model is shown;

[0033] Figure 5 and Figure 6 Show Figure 4 An enlarged schematic diagram of a first sealing structure of a coaxial electric drive system shown;

[0034] Figure 7 Show Figure 4 An enlarged schematic diagram of a bushing of a coaxial electric drive system is shown. DETAILED DESCRIPTION

[0035] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the embodiments set forth herein. Instead, these embodiments are provided to make the present invention comprehensive and complete and to fully convey the concepts of the example embodiments to those skilled in the art.

[0036] The accompanying drawings are only schematic illustrations of the present invention and are not necessarily drawn to scale. The same reference numerals in the drawings represent the same or similar parts, and thus their repeated description will be omitted.

[0037] The words "first", "second" and similar words used in the specific description do not indicate any order, quantity or importance, but are only used to distinguish different components. The term "plurality" means two or more, unless otherwise clearly and specifically defined. In addition, in the description of the present utility model, when it is said that a device is "connected" to another device, this includes not only the case of direct connection, but also the case of indirect connection through other elements.

[0038] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in different embodiments may be combined with each other.

[0039] The coaxial electric drive system is configured in an electric vehicle, and mainly includes a motor and a transmission device (such as a reduction device). The motor has a hollow motor shaft, which is fixedly inserted into the rotor and driven to rotate by the rotor, and the two ends of the motor shaft are rotatably supported by a pair of bearings. The transmission device is connected to the motor shaft in a transmission manner, and the motor shaft transmits power to the transmission device, and then the transmission device transmits power to the wheels through its output shaft. Optionally, the transmission device has two output shafts to transmit power to the left and right wheels respectively. An output shaft of the transmission device is coaxially and gap-arranged in the motor shaft. The following mainly describes the lubrication and cooling scheme of the coaxial electric drive system around the motor shaft, the output shaft coaxially and gap-arranged in the motor shaft, and the components that cooperate with the two shafts. The coaxial electric drive system shown in the drawings of the utility model mainly shows the motor shaft, the output shaft coaxially and gap-arranged in the motor shaft, and other structural designs related to lubrication and cooling.

[0040] Figure 1 The structure of a coaxial electric drive system is shown in FIG. Figure 4 The structure of another coaxial electric drive system is shown; Figure 1 and Figure 4 As shown, the coaxial electric drive system provided by the embodiment of the utility model includes:

[0041] A hollow motor shaft 10 and an output shaft 20 drivingly connected to the motor shaft 10, the output shaft 20 coaxially passes through and extends out of the motor shaft 10, and the output shaft 20 and the first end of the motor shaft 10 (including the first end 20a of the output shaft 20 and the first end 10a of the motor shaft 10) are rotatably supported by bearings 30 respectively;

[0042] The oil input channel P1 leading to the output shaft 20 and the first end of the motor shaft 10 and the bearing channel and the shaft channel communicating with the oil input channel P1, wherein:

[0043] The bearing passage leads to the bearing 30, a first sealing structure (42, 44) is arranged between the bearing 30 and the oil input passage P1, and the bearing passage is formed at least by the first sealing structure;

[0044] The output shaft 20 and the motor shaft 10 are spaced apart to form a shaft channel P2. An end of the shaft channel P2 away from the oil input channel P1 is provided with a second sealing structure (52, 55) that is clearance-matched with the output shaft 20 or the motor shaft 10.

[0045] The oil input channel P1 may be provided in the housing 60 of the coaxial electric drive system, and the housing 60 may be the housing of the motor, the housing of the transmission device, or the housing of other components of the coaxial electric drive system. The oil input channel P1 may also be formed in a component supporting the bearing 30, such as a bearing seat. The outer ring of the bearing 30 may be supported by a bearing seat (not specifically shown in the figure) assembled with the housing 60, or may be directly supported by the housing 60. In some cases, the oil input channel may also be provided in the output shaft 20, or in other components of the coaxial electric drive system.

[0046] The coaxial electric drive system of the present invention reasonably distributes the oil through the bearing channel formed by at least the first sealing structure, so that part of the oil enters the bearing 30 through the bearing channel to lubricate and cool the bearing 30, thereby avoiding the situation where most of the oil leaks from the bearing 30, and allowing enough oil to enter the shaft channel P2 to lubricate and cool the output shaft 20 and the motor shaft 10; the gap size of the bearing channel can be adjusted as needed to adjust the amount of oil entering the bearing 30, and then adjust the amount of oil entering the shaft channel P2.

[0047] The coaxial electric drive system of the utility model effectively blocks the leakage of oil in the shaft channel P2 by means of the second sealing structure arranged in the shaft channel P2, thereby ensuring that the oil effectively lubricates and cools the output shaft 20, the motor shaft 10, the bearing 30 and other components; the second sealing structure is clearance-matched with the output shaft 20 or the motor shaft 10 to reduce the friction loss between the output shaft 20 and the motor shaft 10, thereby ensuring that the motor shaft 10 and the output shaft 20 can both operate stably when the motor is running; the size of the clearance between the second sealing structure and the output shaft 20 / motor shaft 10 can be adjusted as needed, so as to take into account the effect of the second sealing structure in blocking most of the oil leakage in the shaft channel P2 while minimizing the friction loss between the output shaft 20 and the motor shaft 10.

[0048] The coaxial electric drive system of the utility model has a simple overall design, does not occupy an axial space alone, and can achieve effective lubrication and cooling of components such as the output shaft 20, the motor shaft 10, and the bearing 30.

[0049] Figure 2 Indicate Figure 1 The enlarged structure of the first sealing structure of the coaxial electric drive system shown; combined Figure 1 and Figure 2As shown, in some embodiments, the first sealing structure is a seal 42, which is in sealing contact with one of the outer ring and the inner ring of the bearing 30 and is in clearance fit with the other to form a bearing channel. That is, in this embodiment, the gap P31 between the seal 42 and the bearing 30 forms a bearing channel.

[0050] The seal 42 can block most of the oil from the oil input channel P1, allowing only a small portion of the oil to enter the bearing 30 through the bearing channel, while most of the oil can reach the shaft channel P2 between the motor shaft 10 and the output shaft 20, thereby achieving reasonable distribution of the oil.

[0051] The seal 42 may be an oil retaining structure such as a dust cover or a sealing ring. The gap P31 between the seal 42 and the two bearings 30 may be adjusted as needed to adjust the amount of oil entering the corresponding bearing 30 and the shaft passage P2. The bearing 30 may be a ball bearing, but is not limited thereto.

[0052] The thickness of the sealing member 42 can also be adjusted as required, so as to adjust the oil pressure-bearing strength of the sealing member 42. The sealing member 42 can be made of steel or other suitable materials.

[0053] In some embodiments, the seal 42 is in sealing contact with the outer ring 30' of the bearing 30 and is in clearance fit with the inner ring of the bearing 30. The seal 42 is fixed on the outer ring 30' to avoid rotation and has good stability.

[0054] Figure 5 and Figure 6 Indicate Figure 4 The enlarged structure of the first sealing structure of the coaxial electric drive system shown; combined Figures 4 to 6 As shown, in some embodiments, the first sealing structure is a bushing 44, which is connected to the housing 60 of the coaxial electric drive system and is spaced apart from the output shaft 20 and the first end of the motor shaft 10 to form a gap channel P32, and the bearing channel includes the gap channel P32.

[0055] The bushing 44 is used to block the oil input channel P1 and the bearing 30, leaving only the gap channel P32 so that a small part of the oil can enter the bearing 30 through the gap channel P32, while most of the oil can reach the shaft channel P2 between the motor shaft 10 and the output shaft 20, thereby achieving reasonable distribution of the oil.

[0056] The gap size of the gap channel P32 can be adjusted as needed to adjust the amount of oil entering the bearing 30 and the shaft channel P2. The bearing 30 can be a ball bearing, but is not limited thereto.

[0057] The thickness of the bushing 44 can also be adjusted as needed to adjust the strength of the bushing 44 to withstand the oil pressure. The bushing 44 can be made of steel or other suitable materials. The bushing 44 is made of steel and can have sufficient structural strength to withstand the oil pressure and maintain stability.

[0058] In some embodiments, the surfaces of the bushing 44 facing the output shaft 20 and the first end of the motor shaft 10 are respectively embedded with sealing rings 442. By combining the sealing ring 442 with the bushing 44, it is possible to avoid excessive oil leakage caused by using only the bushing 44, and the amount of leaked oil can be adjusted by means of the sealing ring 442 to appropriately reduce the oil entering the bearing 30, so that more oil is diverted to the shaft channel P2. In addition, in the case of using only the bushing 44, in order to minimize the oil entering the bearing 30, it is necessary to strictly control the interval between the bushing 44 and the first end of the output shaft 20 and the motor shaft 10, which is easy to cause friction loss between the bushing 44 and the output shaft 20 and the motor shaft 10 when the motor is running; in the case of combining the sealing ring 442 with the bushing 44, the leakage of oil is effectively reduced by the sealing ring 442, so that the gap between the bushing 44 and the first end of the output shaft 20 and the motor shaft 10 can be set slightly larger, thereby avoiding friction loss when the motor is running.

[0059] The sealing ring 442 can be movably embedded in the surface of the bushing 44, and the sealing ring 442 can block and at least partially make way for the gap channel P32. In this embodiment, the bushing 44 limits the sealing ring 442, but does not fix the sealing ring 442. Under the operating condition of the motor, due to the centrifugal force, the sealing ring 442 can move to partially make way for the gap channel P32, so that an appropriate amount of oil can enter the bearing 30 to cool and lubricate the bearing 30. Under the boost charging condition, due to the gravity, the sealing ring 442 can block the gap channel P32 (or basically block the gap channel P32, or make the gap channel P32 smaller), so that as much oil as possible can enter the shaft channel P2, and the oil can further enter the rotor 80 from the shaft channel P2 to fully cool the rotor 80 (the boost charging condition will utilize the winding, causing the rotor 80 to generate a lot of heat).

[0060] The sealing ring 442 can be clearance-matched with the first end of the output shaft 20 and the motor shaft 10 to at least partially expose the clearance channel P32. In this embodiment, the bushing 44 can fix the sealing ring 442. The sealing ring 442 is clearance-matched with the first end of the output shaft 20 and the motor shaft 10 to partially expose the clearance channel P32, so that an appropriate amount of oil can enter the bearing 30 to cool and lubricate the bearing 30.

[0061] In some embodiments, the sealing ring 442 is provided with an oil groove (not specifically shown in the figure) connecting the oil input channel P1 and the bearing 30, and the bearing channel includes the oil groove. Through the oil groove of the sealing ring 442, a proper amount of oil can enter the bearing 30 to cool and lubricate the bearing 30.

[0062] Figure 7 Indicate Figure 4 An enlarged structure of a bushing of the coaxial electric drive system shown; combined Figures 4 to 7 As shown, in some embodiments, the bushing 44 is provided with a through hole 446 communicating the oil input passage P1 and the shaft passage P2 .

[0063] The oil from the oil input channel P1 can enter the shaft channel P2 through the through hole 446. A plurality of through holes 446 can be provided along the circumference, so that the oil is guided to the shaft channel P2 at multiple points, so as to achieve sufficient lubrication and cooling of the output shaft 20 and the motor shaft 10.

[0064] In some embodiments, the oil input channel P1 is arranged in the housing 60, and the bushing 44 is also provided with: an oil storage chamber 443 connected to the oil input channel P1, arranged on the surface of the bushing 44 facing the oil input channel P1; an oil injection groove P33 connecting the oil storage chamber 443 and the bearing 30, and the bearing channel includes the oil injection groove P33.

[0065] The oil storage chamber 443 is formed into a ring shape following the shape of the bushing 44, and can divert the oil from the oil input channel P1; the oil storage chamber 443 is arranged on the surface of the bushing 44 facing the oil input channel P1, so as to receive the oil from the oil input channel P1 and divert it to the bearing channel and the shaft channel P2.

[0066] The oil spray groove P33 communicates the oil storage chamber 443 and the bearing 30 to guide the oil to the bearing 30 to achieve lubrication and cooling of the bearing 30. Multiple pairs of oil spray grooves P33 can be arranged along the circumferential direction to achieve sufficient lubrication and cooling of the bearing 30.

[0067] In some embodiments, the two ends of the bushing 44 are respectively connected to the housing 60 and cooperate with the output shaft 20 and the first end of the motor shaft 10. The middle part of the bushing 44 is recessed to form an annular oil storage chamber 443; the through hole 446 passes through the oil storage chamber 443, and the oil injection groove P33 is arranged on the surface where the bushing 44 is connected to the housing 60.

[0068] The two ends of the bushing 44 are relatively thick, which can achieve a stable connection with the housing 60 and stably limit the sealing ring 442. The through hole 446 is opened in the oil storage cavity 443, which is convenient for the opening of the through hole 446. The oil injection groove P33 is opened on the surface of the bushing 44, which is also convenient for the opening of the oil injection groove P33.

[0069] In some embodiments, the oil input channel P1 is disposed in the housing 60, and the housing 60 is also provided with an oil drain groove P34 connecting the oil input channel P1 and the bearing 30, and the bearing channel includes the oil drain groove P34. Figure 5 The housing 60 shown in the figure does not have an oil drain groove. Figure 6 The housing 60 shown in the figure is provided with an oil drain groove P34.

[0070] The oil drain groove P34 is provided in the housing 60, so as to guide the oil to the bearing 30 to lubricate and cool the bearing 30. However, the processing cost of providing the oil drain groove P34 in the housing 60 is relatively high and time-consuming, while the design of providing the oil injection groove P33 on the surface of the bushing 44 described in the above embodiment is lower in cost, efficient and easy to implement.

[0071] Based on the different bearing channel setting methods described in the above embodiments, in a specific coaxial electric drive system, a suitable bearing channel can be set according to actual design requirements, such as processing simplification requirements, oil distribution requirements, component simplification requirements, etc.

[0072] Figure 3 Indicate Figure 1 The enlarged structure of the second sealing structure of the coaxial electric drive system shown; combined Figure 1 , Figure 3 and Figure 4 As shown, in some embodiments, the second sealing structure is in sealing contact with the motor shaft 10 and has a clearance fit with the output shaft 20 .

[0073] In this way, when the motor of the coaxial electric drive system is arranged horizontally (the coaxial electric drive system illustrated in the accompanying drawings of the present invention adopts the method of horizontally arranging the motor): under the operating condition of the motor, the oil in the shaft channel P2 is at least partially blocked by the second sealing structure under the action of centrifugal force. Specifically, when the motor is running at high speed, due to the action of centrifugal force, the oil in the shaft channel P2 will stick to the wall of the motor shaft 10 and will not easily leak until the oil height exceeds the height e of the second sealing structure, and the oil will leak from the gap between the second sealing structure and the output shaft 20; under the boost charging condition, the oil in the shaft channel P2 is at least partially blocked by the second sealing structure under the action of gravity. Specifically, when the motor is stationary, due to the action of gravity, the oil in the shaft channel P2 will also stick to the wall of the motor shaft 10 and will not easily leak until the oil height exceeds the height e of the second sealing structure, and the oil will leak from the gap between the second sealing structure and the output shaft 20.

[0074] The height e of the second sealing structure can be adjusted to adjust the gap between the second sealing structure and the output shaft 20 to control the amount of oil in the shaft channel P2. At the same time, it is necessary to ensure that the second sealing structure does not contact the output shaft 20 to avoid friction loss between the output shaft 20 and the motor shaft 10 when the motor is running.

[0075] In some embodiments, reference Figure 1 and Figure 3 As shown, the second sealing structure is a second oil seal 52 fixedly connected to the motor shaft 10. The second oil seal 52 can prevent most of the oil in the shaft channel P2 from leaking, thereby achieving sufficient lubrication and cooling of the motor shaft 10 and the output shaft 20. The thickness of the second oil seal 52 can be adjusted as needed to adjust the strength of the second oil seal 52 to withstand oil pressure.

[0076] In some embodiments, the second oil seal 52 includes a rigid frame 52a connected to the motor shaft 10 and a flexible support leg 52b matched with the output shaft 20. The rigid frame 52a ensures a stable and sealed connection between the second oil seal 52 and the motor shaft 10, and ensures the stability of the overall structure of the second oil seal 52, so that the second oil seal 52 can withstand sufficient oil pressure; the flexible support leg 52b reduces the possible friction loss between the second oil seal 52 and the output shaft 20 when the motor is running. The assembly position of the flexible support leg 52b and the rigid frame 52a can be adjusted to adjust the height e of the second oil seal 52. The rigid frame 52a can be made of steel or other suitable materials, and the flexible support leg 52b can be made of rubber or other suitable materials.

[0077] In some embodiments, reference Figure 4 As shown, the second sealing structure is a boss 55 integrally formed on the inner wall of the motor shaft 10. In the partially coaxial electric drive system, the motor shaft 10 is formed as a shaft structure with radially contracted ends at both ends. In this way, the boss 55 formed on the inner wall of the second end 10b of the motor shaft 10 is used to cooperate with the clearance of the output shaft 20 to achieve blocking of most of the oil in the shaft channel P2, without the need to set up an oil seal separately.

[0078] Among them, considering the manufacturing tolerance, the clearance range of the clearance fit between the output shaft 20 and the motor shaft 10 can be set between 0.3mm and 0.6mm, but not limited thereto. The specific clearance fit value between the output shaft 20 and the motor shaft 10 can be set as long as it can block most of the oil in the shaft channel P2 and minimize the friction loss between the output shaft 20 and the motor shaft 10 when the motor is running.

[0079] Furthermore, combined with Figure 1 and Figure 4 As shown, in some embodiments, the coaxial electric drive system is further provided with a rotor channel P4 connected to the shaft channel P2, and the rotor channel P4 passes through the motor shaft 10 and the rotor 80 sleeved outside the motor shaft 10.

[0080] The rotor passage P4 is used to guide oil to the rotor 80 to achieve lubrication and cooling of the rotor 80 .

[0081] In a coaxial electric drive system, how to effectively introduce the oil used for lubrication and cooling into the rotor 80 is a major design problem. The utility model reasonably distributes the oil through the first sealing structure (42, 44) so ​​that most of the oil enters the shaft channel P2; through the second sealing structure (52, 55), the leakage of the oil in the shaft channel P2 is effectively reduced; and then, through the rotor channel P4 connected to the shaft channel P2, the oil is smoothly introduced into the rotor 80, ensuring sufficient lubrication and cooling of the rotor 80 and reducing the loss of the rotor 80. In addition, the utility model can further ensure that a sufficient amount of oil flows into the rotor 80 under various working conditions such as motor operation conditions and boost charging conditions through the setting of the second sealing structure (52, 55), so as to achieve sufficient lubrication and cooling of the rotor 80.

[0082] The above contents are further detailed descriptions of the present invention in combination with specific preferred implementations, and the specific implementation of the present invention cannot be considered to be limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A coaxial electric drive system, comprising a hollow motor shaft and an output shaft drivingly connected to the motor shaft, the output shaft coaxially passes through and extends out of the motor shaft, and the first ends of the output shaft and the motor shaft are rotatably supported by bearings respectively; It is characterized in that The coaxial electric drive system is provided with an oil input channel leading to the output shaft and the first end of the motor shaft, and a bearing channel and a shaft channel communicating with the oil input channel; The bearing passage leads to the bearing, a first sealing structure is provided between the bearing and the oil input passage, and the bearing passage is formed at least by the first sealing structure; The output shaft and the motor shaft are spaced apart to form the shaft channel, and a second sealing structure which is gap-matched with the output shaft or the motor shaft is provided at one end of the shaft channel away from the oil input channel.

2. The coaxial electric drive system according to claim 1, characterized in that: The first sealing structure is a sealing member, which is in sealing contact with one of the outer ring and the inner ring of the bearing and is in clearance fit with the other one to form the bearing channel.

3. The coaxial electric drive system according to claim 2, characterized in that: The sealing element is in sealing contact with the outer ring and is in clearance fit with the inner ring.

4. The coaxial electric drive system according to claim 1, characterized in that: The first sealing structure includes a bushing, which is connected to the housing of the coaxial electric drive system and is spaced apart from the output shaft and the first end of the motor shaft to form a gap channel, and the bearing channel includes the gap channel.

5. The coaxial electric drive system according to claim 4, characterized in that: Sealing rings are respectively embedded on the surfaces of the bushing facing the output shaft and the first end of the motor shaft; The sealing ring is movably embedded in the surface of the bushing, and the sealing ring can block and at least partially make way for the gap channel, or the sealing ring is gap-matched with the output shaft and the first end of the motor shaft to at least partially expose the gap channel.

6. The coaxial electric drive system according to claim 5, characterized in that: The sealing ring is provided with an oil passage groove communicating with the oil input channel and the bearing, and the bearing channel includes the oil passage groove.

7. The coaxial electric drive system according to claim 4, characterized in that: The bushing is provided with a through hole communicating with the oil input channel and the shaft channel.

8. The coaxial electric drive system according to claim 7, characterized in that: The oil input channel is arranged in the housing, and the bushing is further provided with: An oil storage chamber connected to the oil input channel is arranged on a surface of the bushing facing the oil input channel; An oil spray groove is connected between the oil storage chamber and the bearing, and the bearing channel includes the oil spray groove.

9. The coaxial electric drive system according to claim 8, characterized in that: The two ends of the bushing are respectively connected to the housing and matched with the output shaft and the first end of the motor shaft, and the middle of the bushing is recessed to form the annular oil storage cavity; The through hole passes through the oil storage cavity, and the oil injection groove is arranged on the surface where the bushing is connected to the housing.

10. The coaxial electric drive system according to claim 4, characterized in that: The bushing is made of steel.

11. The coaxial electric drive system according to claim 4, characterized in that: The oil input channel is arranged in the housing, and an oil drain groove communicating the oil input channel and the bearing is also arranged in the housing, and the bearing channel includes the oil drain groove.

12. The coaxial electric drive system according to claim 1, characterized in that: The second sealing structure is in sealing contact with the motor shaft and is in clearance fit with the output shaft.

13. The coaxial electric drive system according to claim 12, characterized in that: The motor of the coaxial electric drive system is arranged horizontally; When the motor is running, the oil in the shaft channel is at least partially blocked by the second sealing structure under the action of centrifugal force; Under the boost charging condition, the oil in the shaft channel is at least partially blocked by the second sealing structure under the action of gravity.

14. The coaxial electric drive system according to claim 12, characterized in that: The second sealing structure is a second oil seal; or The second sealing structure is a boss integrally formed on the inner wall of the motor shaft.

15. The coaxial electric drive system according to claim 14, characterized in that: The second oil seal includes a rigid frame connected to the motor shaft and a flexible support foot matched with the output shaft.

16. The coaxial electric drive system according to claim 1, characterized in that: The coaxial electric drive system is also provided with a rotor channel communicated with the shaft channel, and the rotor channel passes through the motor shaft and the rotor sleeved outside the motor shaft.

Images