Motor shaft oil supply structure and motor

Abstract

The application provides a motor shaft oil supply structure and a motor. The motor shaft oil supply structure comprises: a motor shaft, which is provided with an oil channel in the axial direction, and an oil inlet is formed on the outer periphery of the motor shaft; at least one sealing element, which is sleeved on the outer periphery of the motor shaft and forms an annular oil return gap between the motor shaft and the sealing element, and the sealing element is located on one side of the oil inlet in the axial direction of the motor shaft, wherein the side of the sealing element facing the oil inlet is provided with an oil supply cavity for connecting the oil channel and / or the oil return gap; when the oil pressure of the oil supply cavity is less than a set pressure, at least part of the cooling oil in the oil supply cavity flows out along the oil return gap; when the oil pressure of the oil supply cavity is greater than or equal to the set pressure, the sealing element closes the oil return gap, and the cooling oil in the oil supply cavity flows out from the oil channel. The application can realize on-demand oil supply, reduce system power loss, and improve system efficiency.

Description

Technical Field

[0001] This application relates to the field of electric vehicle technology, and in particular to a motor shaft oil supply structure and a motor. Background Technology

[0002] In recent years, due to the demand for energy conservation and environmental protection, new energy vehicles have developed rapidly. The power source of new energy vehicles is generally an electric motor or a combination of an electric motor and an engine. The motor shaft refers to the connecting shaft at the center of the motor, typically used to connect external devices, thereby enabling the motor to drive other devices to rotate. Rotor shaft cooling oil supply mostly uses an oil pump to introduce cooling oil from inside the motor housing into the rotor shaft. This oil supply method makes it difficult to adjust the oil supply amount as needed. That is, the oil pump continuously and equally supplies oil to the rotor shaft under both high-power and low-power operating conditions, resulting in greater power loss for the entire system under low-power conditions. Summary of the Invention

[0003] This application provides a motor shaft oil supply structure and a motor to achieve on-demand oil supply, reduce system power loss, and improve system efficiency.

[0004] The first aspect of this application provides a motor shaft oil supply structure, which includes: A motor shaft, wherein an oil passage is provided along the axial direction of the motor shaft, and an oil inlet is formed on the outer periphery of the motor shaft; At least one seal is fitted around the outer periphery of the motor shaft and forms an annular oil return gap with the motor shaft. The seal is located on one side of the oil inlet along the axial direction of the motor shaft. The side of the seal facing the oil inlet has an oil supply chamber for connecting the oil passage and / or the oil return gap. When the oil pressure in the oil supply chamber is less than the set pressure, at least a portion of the cooling oil in the oil supply chamber flows out along the oil return gap; When the oil pressure in the oil supply chamber is greater than or equal to the set pressure, the seal closes the oil return gap, and the cooling oil in the oil supply chamber flows out from the oil passage.

[0005] Optionally, the number of the seals is two, and the two seals are disposed opposite each other on both sides of the oil inlet, with the oil supply chamber located between the two seals.

[0006] Optionally, the motor shaft includes an input shaft and an output shaft arranged coaxially, and the two seals are a first seal and a second seal, respectively; The first seal is fitted around the outer periphery of the input shaft and forms the oil return gap between the seal and the input shaft. The second seal is fitted around the outer periphery of the output shaft and forms the oil return gap between the seal and the output shaft.

[0007] Optionally, the input shaft has an inner hole, the output shaft is inserted into the inner hole, and the gap between the outer peripheral surface of the output shaft and the wall of the inner hole forms the oil passage.

[0008] Optionally, the output shaft is exposed at the first end of the input shaft, and the inner hole forms the oil inlet at the first end.

[0009] Optionally, the output shaft includes a shoulder exposed at the first end, and the gap between the shoulder and the first end forms the oil inlet.

[0010] Optionally, the seal includes a first annular portion, the outer ring of the first annular portion being a fixed end, the inner ring of the first annular portion being a free end, and the oil return gap being provided between the free end and the motor shaft. The free end is rotated and deformed around the fixed end to open or close the oil return gap.

[0011] Optionally, the motor shaft oil supply structure further includes a rigid bushing, through which the motor shaft passes and the seal is fixed inside the rigid bushing.

[0012] Optionally, the motor shaft oil supply structure further includes a motor end cover, the motor shaft is rotatably connected to the motor end cover, and the rigid bushing is integrally formed on the motor end cover.

[0013] The second aspect of this application provides an electric motor, which includes any of the motor shaft oil supply structures provided in this application.

[0014] The technical solution provided in this application can achieve the following beneficial effects: The motor shaft oil supply structure provided in this application includes a motor shaft and at least one seal. The motor shaft is provided with an oil passage along its axial direction, and an oil inlet is formed on the outer periphery of the motor shaft. Cooling oil enters the oil passage through the oil inlet to cool the motor shaft. The seal is sleeved on the outer periphery of the motor shaft and forms an annular oil return gap with the motor shaft. The seal is located on one side of the oil inlet along the axial direction of the motor shaft. The side of the seal facing the oil inlet is provided with an oil supply chamber for connecting the oil passage and / or the oil return gap. The oil pressure in the oil supply chamber can be adjusted according to the operating conditions of the motor. After the cooling oil is introduced into the oil supply chamber, the cooling oil in the oil supply chamber further enters the oil passage along the oil inlet and / or flows out along the oil return gap. When the oil pressure in the oil supply chamber is lower than the set pressure, the return oil gap opens, and at least a portion of the cooling oil in the oil supply chamber flows out along the return oil gap, thereby reducing the amount of cooling oil entering the oil circuit of the motor shaft and reducing power loss. When the oil pressure in the oil supply chamber is higher than the set pressure, under the squeezing action of the oil pressure, the seal closes the return oil gap, and the cooling oil in the oil supply chamber completely enters the oil circuit along the oil inlet, ensuring efficient cooling of the motor shaft. Therefore, the embodiments of this application can achieve on-demand oil supply according to the motor's operating conditions, reducing system power loss and improving system efficiency.

[0015] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this application. Attached Figure Description

[0016] Figure 1 A cross-sectional structural diagram of the motor provided in an embodiment of this application; Figure 2 This is a partial structural schematic diagram of the motor shaft oil supply structure provided in the embodiments of this application; Figure 3 for Figure 2 The image shown is a further enlarged view of the local area under low power conditions; Figure 4 for Figure 2 A further magnified view of the local area under high-power conditions; Figure 5 for Figure 1 A magnified view of a section at point A in the middle; Figure 6 This is a cross-sectional structural diagram of the oil supply chamber provided in an embodiment of this application.

[0017] Figure label: 1-Motor shaft; 1a-oil circuit; 1b - Oil inlet; 10 - Input axis; 100 - First end; 12-Output shaft; 120-shoulder; 2-Seals; 2a - First seal; 2b - Second seal; 20 - First annular portion; 200 - Fixed end; 202-Free End; 22-Second annular portion; 24 - Third ring section; 3-Motor end cover; 4-Motor housing; 40 - Inner cavity; 42-External cavity; 5-Rotor; 6-Oil supply chamber; 7- Rigid bushing; 8-Return oil gap. The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0019] In the description of this application, unless otherwise expressly specified and limited, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance; unless otherwise specified or explained, the term "multiple" refers to two or more; the terms "connected," "fixed," etc., should be interpreted broadly. For example, "connected" can be a fixed connection, a detachable connection, an integral connection, or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0020] In the description of this specification, it should be understood that the directional terms such as "upper" and "lower" used in the embodiments of this application are used to describe the angles shown in the accompanying drawings and should not be construed as limiting the embodiments of this application. Furthermore, in the context, it should also be understood that when it is mentioned that an element is connected "upper" or "lower" to another element, it can be directly connected to the other element "upper" or "lower," or indirectly connected to the other element "upper" or "lower" through an intermediate element.

[0021] like Figure 1 As shown in the figure, this application embodiment also provides an electric motor, which includes a motor housing 4, a motor end cover 3, a rotor 5, and a motor shaft 1. The motor end cover 3 is detachably connected to the motor housing 4, together forming the outer shell of the motor; the rotor 5 is disposed inside the motor housing 4, and the motor shaft 1 is rotatably connected to the motor housing 4 and the motor end cover 3 through bearings. The motor shaft 1 is connected to the rotor 5, and the rotor 5 drives the motor shaft 1 to rotate. Cooling oil is provided to the motor shaft 1 through the motor shaft oil supply structure.

[0022] Furthermore, the motor housing 4 includes an inner cavity 40 and an outer cavity 42. The rotor 5 is located in the inner cavity 40, and the motor end cover 3 is detachably connected to the outer cavity 42. The inner cavity 40 and the outer cavity 42 are interconnected through a through hole, and a portion of the motor shaft 1 extends into the outer cavity 42 through the through hole. A bearing can be installed in the through hole to enable the motor shaft 1 to rotate stably.

[0023] like Figures 1-6As shown, the motor shaft oil supply structure provided in this embodiment includes a motor shaft 1 and at least one seal 2. The motor shaft 1 has an oil passage 1a along its axial direction. An oil inlet 1b is formed on the outer periphery of the motor shaft 1. Cooling oil enters the oil passage 1a through the oil inlet 1b to cool the motor shaft 1. The seal 2 is sleeved on the outer periphery of the motor shaft 1. The seal 2 is made of an elastic material such as rubber. The seal 2 is located on one side of the oil inlet 1b along the axial direction of the motor shaft 1. The side of the seal 2 facing the oil inlet 1b is the oil supply chamber 6; that is, the seal 2 constitutes one end face of the oil supply chamber 6 along the motor shaft 1. The oil supply chamber 6 is connected to the oil passage 1a through the oil inlet 1b. After cooling oil is introduced into the oil supply chamber 6, the cooling oil in the oil supply chamber 6 can further enter the oil passage 1a along the oil inlet 1b, thereby cooling the motor shaft 1. The oil supply chamber 6 is connected to an electronic oil pump (not shown in the figure) with adjustable oil pressure. Cooling oil is introduced into the oil supply chamber 6 through the electronic oil pump, thereby regulating the oil pressure in the oil supply chamber 6.

[0024] Furthermore, an annular oil return gap 8 is provided between the seal 2 and the motor shaft 1. This oil return gap 8 is directly connected to the inside of the motor housing. That is, the oil supply chamber 6 can connect to the oil return gap 8, and the cooling oil in the oil supply chamber 6 can further pass through the oil return gap 8 and directly return into the motor housing. When the oil pressure in the oil supply chamber 6 is less than the set pressure, the oil return gap 8 opens, and at least a portion of the cooling oil in the oil supply chamber 6 flows out along the oil return gap 8 to reduce the amount of cooling oil entering the oil passage 1a of the motor shaft 1 and reduce power loss. When the oil pressure in the oil supply chamber 6 is greater than the set pressure, under the squeezing action of the oil pressure, the seal 2 closes the oil return gap 8, and the cooling oil in the oil supply chamber 6 flows out completely from the oil passage 1a to ensure efficient cooling of the motor shaft 1. Thus, the embodiments of this application can achieve on-demand oil supply according to the motor operating conditions, reduce system power loss, and improve system efficiency.

[0025] Specifically, under low-power operating conditions (refer to...) Figure 3 The motor shaft 1 generates less heat and has a lower cooling requirement, which reduces the oil pressure in the oil supply chamber 6, allowing the oil return gap 8 to open, thereby reducing power loss and improving system efficiency; under high power conditions (refer to...) Figure 4 The motor shaft 1 generates a large amount of heat, resulting in a significant cooling demand. Increasing the oil pressure within the oil supply chamber 6 forces the seal 2 to elastically deform away from the oil inlet 1b, closing the return oil gap 8 and achieving efficient cooling of the motor shaft 1. Furthermore, the seal 2's elastic deformation allows for continuous adjustment of the return oil gap 8 within a certain oil pressure range (not exceeding the set pressure), enabling more reliable on-demand oil supply and ensuring that the cooling oil supply matches the system power.

[0026] Furthermore, the seal 2 includes a first annular portion 20. The outer ring of the first annular portion 20 is a fixed end 200, which provides reliable support and positioning for the first annular portion 20, preventing abnormalities such as overall deformation or displacement of the first annular portion 20. The inner ring of the first annular portion 20 is a free end 202, and an oil return gap 8 is provided between the free end 202 and the motor shaft 1. The free end 202 rotates and deforms around the fixed end 200 to open or close the oil return gap 8, so that the first annular portion 20 forms a force-saving lever structure. With a small change in oil pressure, the free end 202 can be pushed to produce a large displacement, thereby making the oil supply adjustment more sensitive and efficient.

[0027] Specifically, in its natural state, the movable end is separated from the motor shaft 1 axially or radially, thus forming an oil return gap 8 between the movable end and the motor shaft 1. When cooling oil is introduced into the oil supply chamber 6, the oil pressure in the oil supply chamber 6 acts on the side of the first annular portion 20 facing the oil supply chamber 6, and pushes the first annular portion 20 to rotate and deform in the direction away from the oil supply chamber 6, thereby reducing the oil return gap 8 or completely closing the oil return gap 8. Since the oil pressure on the first annular portion 20 is evenly distributed on the surface of the first annular portion 20, and the elastic deformation of the first annular portion 20 and its reaction force are mainly close to the fixed end 200, a force-saving lever can be formed, making the oil supply adjustment more sensitive and efficient.

[0028] Furthermore, the first annular portion 20 gradually protrudes towards the side where the oil inlet 1b is located. That is, along the direction from the fixed end 200 to the free end 202, the axial distance between the first annular portion 20 and the oil inlet 1b gradually decreases. The free end 202 and the motor shaft 1 are radially separated to form the oil return gap 8. The surface of the motor shaft 1 does not need to be specially provided with an annular protrusion structure that cooperates with the free end 202, which simplifies the overall structure and reduces the resistance of the cooling oil passing through the oil return gap 8.

[0029] Furthermore, the distance between the fixed end 200 and the free end 202 is a first distance L, and the vertical distance between the fixed end 200 and the surface of the motor shaft 1 is a second distance H, where the first distance L is greater than the second distance H. On the one hand, this ensures that when the first annular portion 20 is deformed outward, the free end 202 can fit against the surface of the motor shaft 1, thereby closing the oil return gap 8. On the other hand, it limits the deformation range of the first annular portion 20, preventing it from being too large and causing it to bulge away from the oil inlet 1b, affecting the normal closing of the oil return gap 8 and also affecting the automatic reset of the first annular portion 20.

[0030] Furthermore, the seal 2 includes a second annular portion 22, which is located on the outer ring of the first annular portion 20. The first annular portion 20 is directly or indirectly connected to the second annular portion 22, and the seal 2 is installed and fixed through the second annular portion 22. The second annular portion 22 protrudes towards the side where the oil inlet 1b is located, which not only increases the mating area of ​​the second annular portion 22 and ensures the stability of the seal 2 installation and fixation, but also allows the second annular portion 22 to extend into the oil supply chamber 6, so that the oil pressure in the oil supply chamber 6 exerts an outward squeezing effect on the second annular portion 22, increasing the reliability of the sealing fit of the second annular portion 22.

[0031] Furthermore, the seal 2 also includes a third annular portion 24, located between the first annular portion 20 and the second annular portion 22. The third annular portion 24 extends radially along the motor shaft 1. The fixed end 200 of the first annular portion 20 is connected to the inner ring of the third annular portion 24, and the end of the second annular portion 22 away from the oil inlet 1b is connected to the outer ring of the third annular portion 24. Specifically, the first annular portion 20 protrudes from the inner ring of the third annular portion 24 toward the side where the oil inlet 1b is located, and the included angle between the first annular portion 20 and the third annular portion 24 is an obtuse angle; the second annular portion 22 protrudes from the outer ring of the third annular portion 24 toward the side where the oil inlet 1b is located, and the included angle between the second annular portion 22 and the third annular portion 24 is a right angle. This design maximizes the effective volume of the oil supply chamber 6 and increases the flexibility of the seal 2 itself, allowing the free end 202 to be more easily rotated and deformed.

[0032] Furthermore, the thickness of the first annular portion 20 is less than the thickness of the second annular portion 22, and the thickness of the first annular portion 20 is less than the thickness of the third annular portion 24, so that the first annular portion 20 has the best flexibility relative to the second annular portion 22 and the third annular portion 24, thereby ensuring that the elastic deformation of the seal 2 occurs preferentially in the first annular portion 20, and ensuring that the second annular portion 22 and the third annular portion 24 together play a reliable supporting role.

[0033] like Figure 5 and Figure 6As shown, in some embodiments, there are two seals 2, namely a first seal 2a and a second seal 2b. The first seal 2a and the second seal 2b are arranged opposite each other on both sides of the oil inlet 1b, and the oil supply chamber 6 is located between the first seal 2a and the second seal 2b. That is, the first seal 2a and the second seal 2b respectively form the two end faces of the oil supply chamber 6. On the one hand, the two ends of the oil supply chamber 6 respectively form an oil return gap 8 for oil return, which can ensure the oil return speed under low power conditions, fully reduce power damage, and ensure the sealing effect under high power conditions, thereby ensuring the cooling effect. On the other hand, by forming the oil supply chamber 6 with the oppositely arranged first seal 2a and the second seal 2b, it is only necessary to set a bushing structure around the outer periphery of the motor shaft 1 and install the first seal 2a and the second seal 2b in the bushing to form the oil supply chamber 6. This simplifies the overall structure of the motor shaft oil supply structure and basically does not affect the original structure of the motor, thereby improving the versatility of the motor shaft oil supply structure.

[0034] The set pressures of the first seal 2a and the second seal 2b can be the same. That is, the oil return gap 8 of the first seal 2a and the oil return gap 8 of the second seal 2b can open simultaneously (when the oil pressure in the oil supply chamber 6 is less than the set pressure) or close simultaneously (when the oil pressure in the oil supply chamber 6 is greater than or equal to the set pressure). Alternatively, the set pressures of the first seal 2a and the second seal 2b can be different. That is, the oil return gap 8 of the first seal 2a and the oil return gap 8 of the second seal 2b can open sequentially (when the oil pressure in the oil supply chamber 6 gradually decreases) or close sequentially (when the oil pressure in the oil supply chamber 6 gradually increases).

[0035] Furthermore, the motor shaft 1 includes an input shaft 10 and an output shaft 12 arranged coaxially, thus forming a coaxial transmission method. This makes the overall structure more compact, which is beneficial for vehicle layout. In addition, the coaxial transmission method has high transmission efficiency and smooth transmission. The input shaft 10 can be supported by bearings in the through hole of the motor housing 4, and the output shaft 12 can be supported by bearings in the motor end cover 3.

[0036] Furthermore, when the motor shaft 1 includes an input shaft 10 and an output shaft 12 arranged coaxially, the first seal 2a is sleeved on the outer periphery of the input shaft 10 and forms an oil return gap 8 between it and the input shaft 10, so that the cooling oil in the oil supply chamber 6 can return along the surface of the input shaft 10; the second seal 2b is sleeved on the output shaft 12 and forms an oil return gap 8 between it and the output shaft 12, so that the cooling oil in the oil supply chamber 6 can return along the surface of the output shaft 12.

[0037] Furthermore, when the motor shaft 1 includes an input shaft 10 and an output shaft 12 coaxially arranged, the input shaft 10 has an inner hole, and the output shaft 12 passes through the inner hole. The gap between the outer peripheral surface of the output shaft 12 and the hole wall of the inner hole of the input shaft 10 forms an oil passage 1a. That is, oil is supplied to the gap between the output shaft 12 and the input shaft 10, thereby simultaneously cooling the input shaft 10 and the output shaft 12. There is no need to set up special flow channel structures for the output shaft 12 and the input shaft 10 respectively, so that the input shaft 10 and the output shaft 12 maintain the integrity of their own structures. This can ensure the structural strength of the input shaft 10 and the output shaft 12, and simplify the structural complexity of the input shaft 10 and the output shaft 12, thereby reducing production costs.

[0038] Furthermore, the end of the input shaft 10 facing the end cover is designated as the first end 100, and a portion of the output shaft 12 is exposed at the first end 100 of the input shaft 10. The inner bore of the input shaft 10 forms an oil inlet 1b for the oil passage 1a at the first end 100. On one hand, this forms a continuous structure around the circumference of the motor shaft 1, thereby improving the uniformity of cooling of the motor shaft 1; on the other hand, it eliminates the need for a dedicated oil inlet channel structure on the bore wall of the inner bore, maintaining the integrity of the output shaft 12's own structure. Understandably, in other embodiments, the oil inlet 1b may also be located in the middle of the input shaft 10, for example, one or more through-hole-shaped oil inlets may be provided in the middle of the input shaft 10.

[0039] Furthermore, the output shaft 12 includes a shoulder 120, which is exposed at the first end 100. The gap between the shoulder 120 and the first end 100 forms an oil inlet 1b of the oil passage 1a. The shoulder 120 confines the cooling oil in the oil inlet 1b, thereby restricting the flow direction of the cooling oil in the oil inlet 1b and ensuring that the cooling oil in the oil inlet 1b can only flow into the oil passage in the axial direction and will not flow in the reverse direction in the axial direction.

[0040] Furthermore, the shoulder 120 is configured as an arc surface on the side facing the first end 100. Along the direction close to the first end 100, the radial dimension of the arc surface gradually decreases, so that the oil inlet 1b forms a constricted structure. In other words, the cross-section of the oil inlet 1b gradually decreases as it approaches the oil passage 1a, thereby gradually increasing the flow rate of the coolant and improving the cooling effect.

[0041] Furthermore, the motor shaft oil supply structure also includes a rigid bushing 7, which can be fixed to the motor housing 4 or the motor end cover 3, as long as the installation and fixation of the rigid bushing 7 can be achieved. The motor shaft 1 passes through the rigid bushing 7, and at least one seal 2 is fixed to the rigid bushing 7. In this embodiment, both the first seal 2a and the second seal 2b are fixed inside the rigid bushing 7. The inner wall surface of the rigid bushing 7, the outer wall surface of the motor shaft 1, and the first seal 2a and the second seal 2b together form the oil supply chamber 6. On the one hand, the rigid bushing 7 provides support and positioning for the first seal 2a and the second seal 2b, thereby fixing the first seal 2a and the second seal 2b in place and preventing any abnormalities such as displacement of the first seal 2a or the second seal 2b during use, which would affect the normal oil supply to the motor shaft 1 or the oil return of the system. On the other hand, the rigid bushing 7 provides reliable limiting around the first seal 2a and the second seal 2b in the circumferential direction, ensuring that the first seal 2a and the second seal 2b can only deform along the axial direction of the motor shaft 1, thus preventing unnecessary oil pressure loss in the oil supply chamber 6.

[0042] Furthermore, the rigid bushing 7 is disposed in the outer cavity 42. For example, the outer cavity 42 is increased in axial depth to form a space for the rigid bushing 7. On the one hand, the rigid bushing 7 is disposed in the outer cavity 42 with the motor end cover 3. Only the motor end cover 3 needs to be removed to maintain or replace the internal motor shaft oil supply structure (e.g., seal 2), reducing the maintenance cost in later use. On the other hand, the rigid bushing 7 does not occupy the space of the inner cavity 40 where the rotor 5 is located, and basically does not change the original structure of the motor housing 4, which can reduce the production cost of product improvement.

[0043] Furthermore, the motor shaft oil supply structure also includes a motor end cover 3. The motor shaft 1 is rotatably connected to the motor end cover 3 via bearings, and a rigid bushing 7 is integrally formed on the motor end cover 3. This not only improves the coaxiality between the rigid bushing 7 and the motor shaft 1, thereby forming a uniform oil return gap 8 between the seal 2 and the motor shaft 1, preventing uneven oil return gap 8 from affecting its normal closure, but also minimizes the number of parts, simplifies the assembly process, and improves production efficiency. Understandably, the rigid bushing 7 can also be connected to the motor end cover 3 by detachable means such as bolts, or it can be connected to the motor end cover 3 by non-detachable means such as welding.

[0044] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A motor shaft oil supply structure, characterized in that, include: A motor shaft, wherein an oil passage is provided along the axial direction of the motor shaft, and an oil inlet is formed on the outer periphery of the motor shaft; At least one seal is fitted around the outer periphery of the motor shaft and forms an annular oil return gap with the motor shaft. The seal is located on one side of the oil inlet along the axial direction of the motor shaft. The side of the seal facing the oil inlet has an oil supply chamber for connecting the oil passage and / or the oil return gap. When the oil pressure in the oil supply chamber is less than the set pressure, at least a portion of the cooling oil in the oil supply chamber flows out along the oil return gap; When the oil pressure in the oil supply chamber is greater than or equal to the set pressure, the seal closes the oil return gap, and the cooling oil in the oil supply chamber flows out from the oil passage.

2. The motor shaft oil supply structure according to claim 1, characterized in that, The number of seals is two, and the two seals are arranged opposite each other on both sides of the oil inlet, with the oil supply chamber located between the two seals.

3. The motor shaft oil supply structure according to claim 2, characterized in that, The motor shaft includes an input shaft and an output shaft arranged coaxially, and the two seals are a first seal and a second seal, respectively. The first seal is fitted around the outer periphery of the input shaft and forms the oil return gap between the seal and the input shaft. The second seal is fitted around the outer periphery of the output shaft and forms the oil return gap between the seal and the output shaft.

4. The motor shaft oil supply structure according to claim 3, characterized in that, The input shaft has an inner hole, the output shaft is inserted into the inner hole, and the gap between the outer peripheral surface of the output shaft and the wall of the inner hole forms the oil passage.

5. The motor shaft oil supply structure according to claim 4, characterized in that, The output shaft is exposed at the first end of the input shaft, and the inner hole forms the oil inlet at the first end.

6. The motor shaft oil supply structure according to claim 5, characterized in that, The output shaft includes a shoulder that is exposed at the first end, and the gap between the shoulder and the first end forms the oil inlet.

7. The motor shaft oil supply structure according to any one of claims 1-6, characterized in that, The sealing element includes a first annular portion, the outer ring of the first annular portion is a fixed end, the inner ring of the first annular portion is a free end, and the oil return gap is provided between the free end and the motor shaft. The free end rotates and deforms around the fixed end to open or close the oil return gap.

8. The motor shaft oil supply structure according to any one of claims 1-6, characterized in that, The motor shaft oil supply structure also includes a rigid bushing, through which the motor shaft passes and the seal is fixed inside the rigid bushing.

9. The motor shaft oil supply structure according to claim 8, characterized in that, The motor shaft oil supply structure also includes a motor end cover, the motor shaft is rotatably connected to the motor end cover, and the rigid bushing is integrally formed on the motor end cover.

10. An electric motor, characterized in that, Includes the motor shaft oil supply structure as described in any one of claims 1-9.

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