Motor shaft, driving motor and new energy vehicle

Abstract

The application discloses a motor shaft, which comprises a shaft body, wherein the shaft body is provided with an oil feeding channel, the oil feeding channel is provided with an oil inlet, the shaft body is provided with a first oil injection hole and a second oil injection hole which are spaced apart along the radial direction of the shaft body, and the first oil injection hole is located between the oil inlet and the second oil injection hole; the oil feeding channel comprises an oil guiding section and an oil feeding section which are communicated with each other, the hole diameter of the oil guiding section is smaller than the hole diameter of the oil feeding section to form an oil guiding step for guiding part of the cooling oil to flow directly to the second oil injection hole from the first oil injection hole, the oil guiding step is located between the oil inlet and the first oil injection hole, the oil guiding step has a set height, and the oil guiding step and the first oil injection hole have a set interval. The application further discloses a driving motor provided with the motor shaft and a new energy vehicle provided with the driving motor. The application can balance the oil amount flowing into the first oil injection hole and the second oil injection hole and improve the overall cooling effect of the driving motor.

Description

Technical Field

[0001] This invention relates to the field of motor technology, and in particular to a motor shaft, a drive motor, and a new energy vehicle. Background Technology

[0002] The drive motors in new energy vehicles generate a significant amount of heat during operation (primarily from the stator and rotor). To ensure their performance and lifespan, cooling is essential. Traditionally, this involves installing cooling channels inside the motor housing, with a cooling medium flowing through these channels to remove some of the heat. However, this method is slow because the cooling medium cannot directly contact the main heat-generating components (stator and rotor), often failing to meet cooling requirements. Therefore, oil-cooled motors have gradually replaced traditional oil-cooled motors. Oil-cooled motors use cooling oil to directly contact the main heat-generating components, removing their heat and achieving higher cooling efficiency. However, traditional oil-cooled motors typically cool by spraying water towards the stator windings, leaving other major heat-generating areas, such as the middle of the stator and the rotor core, uncooled. In some cases, this still falls short of cooling requirements. In recent years, with technological advancements, oil-cooled motors have emerged that can cool most of the main heat-generating components, further improving cooling efficiency. For example, Chinese patent application CN114567102A discloses an oil-cooled motor rotor cooling structure, whose heat dissipation oil circuit can directly cool the main heat-generating parts on the rotor core and stator core, further improving cooling efficiency.

[0003] The cooling structure disclosed in this patent, as well as similar products, suffer from the following problems: This technology requires an oil delivery channel on the motor shaft, with oil holes arranged radially along the channel to connect it to the cooling oil path. Two sets of these oil holes are spaced axially (generally at both ends). The high-speed rotation of the motor shaft forces the cooling oil from the delivery channel through these holes into the cooling oil path. Since one set of oil holes is closer to the inlet of the delivery channel than the other, the cooling oil preferentially flows through the hole closer to the inlet. Consequently, the cooling oil is preferentially ejected from the hole closer to the inlet into the corresponding cooling oil path. That is, the amount of cooling oil flowing into different cooling oil paths is different. This imbalance in oil distribution leads to varying cooling effects, thus limiting the cooling effect on some key heat-generating components. Summary of the Invention

[0004] This invention provides a motor shaft, a drive motor, and a new energy vehicle to solve the problem in the prior art where the cooling effect on some major heat-generating components is poor due to the unbalanced distribution of cooling oil.

[0005] The present invention adopts the following technical solution: a motor shaft, including a shaft body, wherein the shaft body is provided with an oil supply channel along its axial direction, the oil supply channel having an oil inlet, and the shaft body is provided with an oil injection hole along its radial direction to connect the oil supply channel to the outside, the oil injection hole including a first oil injection hole and a second oil injection hole arranged at intervals along the axial direction of the shaft body, and the first oil injection hole being located between the oil inlet and the second oil injection hole; the oil supply channel includes an oil guiding section and an oil supply section that are interconnected, the diameter of the oil guiding section being smaller than the diameter of the oil supply section to form an oil guiding step for allowing part of the cooling oil to flow directly to the second oil injection hole by passing over the first oil injection hole, the oil guiding step being located between the oil inlet and the first oil injection hole, and the oil guiding step having a set height, and the oil guiding step having a set distance from the first oil injection hole.

[0006] This invention offers the following advantages: By segmenting the oil supply channel within the shaft body into an oil guiding section and an oil supply section, and manufacturing the process such that the orifice diameter of the oil guiding section is smaller than that of the oil supply section to form an oil guiding step, a height difference is created. Due to this height difference, a portion of the cooling oil flowing from the oil guiding section to the oil supply section flows in a parabolic trajectory. After this parabolic flow, the cooling oil falls into the oil supply section, having a landing point. By designing the distance between the oil guiding step and the first oil injection hole, the first oil injection hole is positioned between the landing point and the oil guiding step. This allows a portion of the cooling oil to bypass the first oil injection hole and flow directly to the second oil injection hole. Through this design, compared to existing technologies, the flow rates of cooling oil ejected from the first and second oil injection holes can be balanced, thereby producing approximately the same cooling effect on the main heat-generating components within the drive motor, thus improving the overall cooling effect on the drive motor.

[0007] Preferably, the set spacing is a selected value between 1mm and 5mm. Considering parameters such as the overall size of different motors, the location of the oil circuit, and the amount of oil entering the oil delivery channel per unit time, the set spacing that can produce a balanced oil volume effect under different conditions can be verified through experiments.

[0008] Preferably, the set spacing is a selected value between 2mm and 15mm. A set spacing within this range can produce a better effect on balancing the oil volume.

[0009] Preferably, the minimum diameter of the first injection hole is smaller than the minimum diameter of the second injection hole. Regardless of whether the diameters of the first and second injection holes are constant or variable, the amount of cooling oil flowing through them per unit time is limited by the minimum diameter. Therefore, by the above arrangement, the amount of oil flowing through the first injection hole per unit time is reduced, which further balances the amount of oil flowing to the first and second injection holes.

[0010] Preferably, both the first and second injection holes are circular holes. The first injection hole includes an inner section and an outer section that are interconnected. The diameter of the outer section and the diameter of the second injection hole are both larger than the diameter of the inner section. On the one hand, since the diameter of the inner section is smaller than the diameter of the second injection hole, the aforementioned goal of having a minimum diameter of the first injection hole smaller than the minimum diameter of the second injection hole can be achieved. On the other hand, since the diameter of the inner section is smaller than the diameter of the outer section, the outer section can be machined first from the outside of the motor shaft, and then the inner section can be further machined, which facilitates manufacturing.

[0011] Preferably, the oil guide section is equipped with a speed-increasing component to enhance the flow rate of the cooling oil. The size of the speed-increasing component increases uniformly along the axial direction of the shaft. By providing the speed-increasing component, since its cross-sectional area increases uniformly along the axial direction of the shaft, the cross-sectional area of ​​the cooling oil flowing through the oil guide section decreases uniformly. According to fluid mechanics equations, for incompressible liquids like cooling oil, the flow rate increases due to the decrease in cross-sectional area; that is, the speed-increasing component can enhance the flow rate of the cooling oil. As mentioned earlier, some cooling oil falls into the oil supply section after following a parabolic flow trajectory, having a landing point. With the set distance L remaining constant, the speed-increasing component allows the cooling oil in the oil guide section to flow towards the oil supply section at a higher flow rate. Consequently, more cooling oil can bypass the first injection hole and flow directly to the second injection hole, better balancing the oil volume.

[0012] Preferably, the speed-up component includes a booster shaft and at least two booster plates formed on the booster shaft along the axial direction of the booster shaft, and the booster plates are evenly distributed circumferentially along the booster shaft.

[0013] To solve the above-mentioned technical problems, the present invention also adopts the following technical solution: a drive motor, including a rotor core and a motor shaft as described in any one of the above technical solutions. The rotor core is positioned on the outer ring of the motor shaft. The rotor core is provided with a first cooling oil passage and a second cooling oil passage. The first cooling oil passage is connected to an oil delivery channel through a first oil injection hole, and the second cooling oil passage is connected to the oil delivery channel through a second oil injection hole. Because the drive motor uses the aforementioned motor shaft, the drive motor can achieve a better cooling effect.

[0014] Preferably, the rotor core is formed by stacking multiple rotor laminations. Both ends of the rotor core are provided with rotor end plates for reinforcing the rotor laminations. The end face of the rotor end plate facing the rotor core is provided with a groove. The end face of the rotor core cooperates with the groove to form a connecting channel. The first cooling oil passage is connected to the first oil injection hole through the connecting channel, and the second cooling oil passage is connected to the second oil injection hole through the connecting channel.

[0015] To solve the above-mentioned technical problems, the present invention also adopts the following technical solution: a new energy vehicle, including a drive motor as described in the above technical solution.

[0016] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a motor shaft provided in Embodiment 1 of the present invention;

[0018] Figure 2 This is a schematic diagram of the structure in Embodiment 1 in which a rotor core is mounted on the outside of the motor shaft;

[0019] Figure 3 yes Figure 2 Exploded view of the middle structure;

[0020] Figure 4 yes Figure 2 A sectional view of the middle structure;

[0021] Figure 5 yes Figure 4 An enlarged schematic diagram of part A in the middle;

[0022] Figure 6 This is a radial cross-sectional view of the motor shaft along the first oil injection hole provided in Embodiment 2;

[0023] Figure 7 This is a radial cross-sectional view of the motor shaft along the second oil injection hole provided in Embodiment 2;

[0024] Figure 8 This is a partial structural schematic diagram of the motor shaft provided in Embodiment 3;

[0025] Figure 9 This is a schematic diagram of the oil guide section of the motor shaft along the axial direction in Embodiment 3;

[0026] Figure 10 It is along Figure 9 A cross-sectional view along the BB direction.

[0027] Among them, 1. Shaft, 10. Oil supply channel, 100. Oil inlet, 101. Oil guide section, 102. Oil supply section, 11. First oil injection hole, 110. Inner hole section, 111. Outer hole section, 12. Second oil injection hole, 13. Oil guide step, 14. Speed-up component, 140. Booster shaft, 141. Booster plate, 15. Spline end, 16. Resolver end, 2. Rotor core, 20. Connecting channel, 21. First cooling oil channel, 22. Second cooling oil channel, 3. Rotor end plate, 30. Groove. Detailed Implementation

[0028] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0029] Embodiments of the present invention will now be described with reference to the accompanying drawings.

[0030] Example 1: This example provides a motor shaft, such as... Figure 1 As shown, the motor shaft includes a shaft body 1, with a splined end 15 and a resolver end 16 at its two ends. The shaft body 1 has an oil supply channel along its axial direction, with an oil inlet 100 located at the splined end 15. Cooling oil enters the oil supply channel from the oil inlet 100 and flows along the channel from the splined end 15 to the resolver end 16. In this embodiment, the shaft body 1 has oil injection holes along its radial direction that connect the oil supply channel to the outside. The oil injection holes include a first oil injection hole 11 and a second oil injection hole 12 spaced apart along the axial direction of the shaft body 1. The first oil injection hole 11 is located between the oil inlet 100 and the second oil injection hole 12. Specifically, in this embodiment, three of each of the first and second oil injection holes 11 are provided and evenly distributed along the circumference of the shaft body 1. In other embodiments, one or more may be used. Figure 2 , Figure 3 and Figure 4 As shown, when the motor shaft is in use, a rotor core 2 is installed on its exterior. Specifically, the rotor core 2 is formed by stacking multiple rotor laminations, and rotor end plates 3 are provided at both ends of the rotor core 2 to reinforce the rotor laminations. The rotor core 2 is provided with a first cooling oil channel 21 and a second cooling oil channel 22. The first cooling oil channel 21 is connected to the oil delivery channel 10 through a first oil injection hole 11, and the second cooling oil channel 22 is connected to the oil delivery channel 10 through a second oil injection hole 12. In this embodiment, a groove 30 is provided on the end face of the rotor end plate 3 facing the rotor core 2. The end face of the rotor core 2 mates with the groove 30 to form a connecting channel 20. The first cooling oil channel 21 is connected to the first oil injection hole 11 through the connecting channel 20, and the second cooling oil channel 22 is connected to the second oil injection hole 12 through the connecting channel 20. With the above settings, a complete cooling oil circulation circuit can be formed. External cooling oil enters the oil supply channel 10 through the oil inlet 100 under the power of the oil pump. Under the high-speed rotation of the motor shaft, it is thrown into the first oil injection hole 11 and the second oil injection hole 12. It then enters the first cooling oil passage 21 through the first oil injection hole 11 and the connecting channel 20, and enters the second cooling oil passage 22 through the second oil injection hole 12 and the connecting channel 20, thus completing the cooling of the main heat-generating parts such as the rotor core 2 and the stator coil.

[0031] Combination Figure 5 As shown in the diagram, in order to balance the amount of oil entering the first oil injection hole 11 and the second oil injection hole 12, the oil delivery channel 10 is designed to include an interconnected oil guiding section 101 and an oil supply section 102. The diameter of the oil guiding section 101 is smaller than the diameter of the oil supply section 102 to form an oil guiding step 13. Positionally, the oil guiding step 13 is located between the oil inlet 100 and the first oil injection hole 11. The oil guiding step 13 has a set height H, and a set distance L exists between the oil guiding step 13 and the first oil injection hole 11. Because the oil guiding step 13 can create a height difference between the oil guiding section 101 and the oil supply section 102, the cooling oil flows across the oil guiding step 13 with a parabolic trajectory. Therefore, some cooling oil can directly cross the first oil injection hole 11 and flow directly to the second oil injection hole 12. In other words, the oil guide step 13 serves the function of allowing a portion of the cooling oil flowing through it to directly bypass the first injection hole 11 and flow directly to the second injection hole 12. Compared to existing structures, this reduces the amount of oil flowing out of the first injection hole 11 and correspondingly increases the amount of oil flowing out of the second injection hole 12, thus balancing the oil volume. Understandably, the distance between the oil guide step 13 and the first injection hole 11 also needs to be designed to control the amount of cooling oil flowing directly from the first injection hole 11 to the second injection hole 12. By segmenting the oil channel 10 inside the shaft body 1 into an oil guiding section 101 and an oil supply section 102, the diameter of the oil guiding section 101 is made smaller than that of the oil supply section 102 during manufacturing to form an oil guiding step 13. The oil guiding step 13 creates a height difference, and part of the cooling oil flowing from the oil guiding section 101 to the oil supply section 102 will flow in a parabolic trajectory due to the aforementioned height difference. After the parabolic flow trajectory, this part of the cooling oil falls into the oil supply section 102, where it has a landing point. By designing the distance between the oil guiding step 13 and the first oil injection hole 11, the first oil injection hole 11 is located between the landing point and the oil guiding step 13. This allows part of the cooling oil to bypass the first oil injection hole 11 and flow directly to the second oil injection hole 12. Through the above design of the present invention, the flow rate of cooling oil sprayed from the first oil injection hole 11 and the second oil injection hole 12 can be balanced compared with the prior art, thereby producing approximately the same cooling effect on the main heat-generating components in the drive motor, and improving the overall cooling effect on the drive motor.

[0032] In this embodiment, the following experimental method is used to verify whether the motor shaft can achieve the effect of balancing oil volume: A ring-shaped and transparent cover is placed over the motor shaft to be tested; the motor shaft is then tightly fitted to the output shaft of the motor to facilitate motor shaft rotation control; an oil pipe is rotatably connected to the oil inlet end of the motor shaft, and an oil pump is installed at the other end of the oil pipe, so that cooling oil can be pumped into the oil delivery channel of the motor shaft through the oil pump. After the experiment begins, the cooling oil is pumped into the oil delivery channel of the motor shaft through the oil pump, and at the same time, the motor shaft is driven to rotate. The rotating motor shaft sprays the cooling oil in the oil delivery channel through the first oil spray hole and the second oil spray hole onto the cover. Since the cooling oil has a certain viscosity, the sprayed cooling oil can adhere to the cover, thereby forming a ring-shaped oil mark with a certain width on the cover. The oil mark formed on the cover by the cooling oil sprayed from the first oil spray hole is named the first oil mark, and the corresponding oil mark formed on the cover by the cooling oil sprayed from the second oil spray hole is named the second oil mark. By comparing the width difference between the first and second oil stains, it can be determined whether the amount of oil sprayed from the first and second injection holes is balanced.

[0033] After conducting the aforementioned experiments on a motor shaft with an internal oil channel diameter that remains unchanged in the prior art, the inventors found that when the rotational speed is below 3000 rpm, the width ratio of the first oil trace and the second oil trace is approximately 3:1. This means that the amount of oil ejected from the first injection hole is about three times that of the second injection hole, indicating a significant imbalance. When the rotational speed exceeds 3000 rpm, the width of the second oil trace decreases significantly, and it even disappears when the rotational speed exceeds 4000 rpm. The inventors designed experiments to verify the balanced oil volume effect achieved by the motor shaft provided in this embodiment. Specifically, motor shafts with different set spacing L were manufactured, and the corresponding width ratio of the first and second oil traces was verified through the aforementioned experimental process. In this embodiment, the set height H of the oil guide step is 1 mm. It is easy to understand that the amount of oil flowing directly from the first injection hole to the second injection hole is also affected by the height of the oil guide step. Theoretically, the larger the value of H, the greater the height difference, and the easier it is for the cooling oil to pass over the first injection hole. However, when the value of H is too large, it will result in insufficient oil entering the first injection hole. Therefore, in this embodiment, the set height H of the oil guide step is a fixed value of 1mm during the above experiment. In other embodiments, the height of the oil guide step can also be adjusted. The inventors conducted multiple experiments to verify the width ratio between the first and second oil traces under different set spacings L, obtaining the following table:

[0034]

[0035] In this embodiment, the set spacing L is 3mm. Furthermore, through the aforementioned experiments, the inventors discovered that, compared to existing motor shaft designs, a set spacing L between 1mm and 50mm effectively balances the oil volume. Moreover, a set spacing L between 2mm and 15mm produces an even better oil volume balancing effect. Additionally, compared to existing technologies, the improvement is more significant when the motor shaft rotates at high speeds of 4000-14000rpm.

[0036] Example 2: This example also provides a motor shaft. The difference between this example and the previous example is that the diameters of the first oil injection hole 11 and the second oil injection hole 12 are designed. Specifically, in this example, the minimum diameter of the first oil injection hole 11 is smaller than the minimum diameter of the second oil injection hole 12. The minimum diameter refers to the smallest internal diameter of the oil injection hole. When the diameter of the oil injection hole is a fixed value, the minimum diameter is that fixed value. When the diameter of the oil injection hole is a variable value (for example, the oil injection hole includes multiple segments, each with a different diameter), the minimum diameter is the diameter of the segment with the smallest diameter. Regardless of whether the diameters of the first oil injection hole 11 and the second oil injection hole 12 are fixed or variable values, the amount of cooling oil flowing through them per unit time is limited by the minimum diameter. Therefore, by setting it up as described above, the amount of oil flowing through the first injection hole 11 per unit time is reduced, which increases the amount of cooling oil flowing to the second injection hole 12 and further balances the amount of oil flowing to the first injection hole 11 and the second injection hole 12.

[0037] Combination Figure 6 and Figure 7 As shown in the diagram, in this embodiment, both the first injection hole 11 and the second injection hole 12 are circular holes. The first injection hole 11 includes an inner hole section 110 and an outer hole section 111 that are interconnected. The diameter of the outer hole section 111 and the diameter of the second injection hole 12 are both larger than the diameter of the inner hole section 110. On the one hand, since the diameter of the inner hole section 110 is smaller than the diameter of the second injection hole 12, the aforementioned goal of having a minimum diameter of the first injection hole 11 smaller than the minimum diameter of the second injection hole 12 can be achieved. On the other hand, since the diameter of the inner hole section 110 is smaller than the diameter of the outer hole section 111, the outer hole section 111 can be machined first from the outside of the motor shaft, and then the inner hole section 110 can be further machined, which facilitates manufacturing. It is understood that in other embodiments, the first injection hole 11 and the second injection hole 12 can also be other structural forms besides circular holes, such as rectangular holes or trapezoidal holes. For ease of manufacturing, the diameter of the second injection hole 12 can be the same as the diameter of the outer hole section 111, so that the same tool can be used to drill the hole. Of course, the two can also be manufactured differently.

[0038] In Example 1, the set spacing L of the motor shaft is 3mm. During the experiment, the width ratio of the first oil trace to the second oil trace was 1.3:1. In this example, the aperture of the first oil injection hole and the second oil injection hole of the motor shaft are further modified as described above. The aperture of the first oil injection hole is changed from 3mm to 1.3mm, so that when the set spacing L is 3mm, the width ratio of the first oil trace to the second oil trace is close to 1, which means that a better oil balance effect can be achieved.

[0039] Example 3: This example also provides a motor shaft, such as... Figure 8 , Figure 9 and Figure 10 As shown, the difference between this embodiment and the previous embodiment is that, in this embodiment, a speed-increasing component 14 for increasing the flow rate of cooling oil is provided in the oil guide section 101. The size of the speed-increasing component 14 is uniformly increased along the axial direction of the shaft 1. By providing the speed-increasing component 14, since the cross-sectional area of ​​the speed-increasing component 14 is uniformly increased along the axial direction of the shaft 1, the cross-sectional area of ​​the cooling oil flowing through the oil guide section 101 is uniformly reduced. According to the fluid dynamics equation, for an incompressible liquid like cooling oil, its flow rate increases due to the decrease in cross-sectional area. That is, the speed-increasing component 14 can increase the flow rate of the cooling oil. As before, some cooling oil falls into the oil supply section 102 after following a parabolic flow trajectory. It has a landing point. With the set distance L unchanged, after providing the speed-increasing component 14, the cooling oil in the oil guide section 101 can flow to the oil supply section 102 at a higher flow rate. Correspondingly, more cooling oil can pass over the first oil injection hole 11 and flow directly to the second oil injection hole 12, thus better balancing the oil volume.

[0040] The speed-up component 14 in this embodiment includes a booster shaft 140 and six booster plates 141 formed along the axial direction of the booster shaft 140, and the booster plates 141 are evenly distributed circumferentially along the booster shaft 140. It is understood that the number of booster plates 141 can be two or more. During manufacturing, the booster shaft 140 and the booster plates 141 are integrally formed by injection molding. During the injection molding process, the draft angle of the mold itself causes the booster shaft 140 and the booster plates 141 to gradually shrink, naturally forming a speed-up component 14 with a uniformly varying cross-sectional area during the injection molding process, ensuring its smooth surface, which is conducive to the flow of cooling oil. In other words, the speed-up component 14 can be directly produced through injection molding, which is convenient to manufacture and has a low cost.

[0041] In Example 1, the set spacing L of the motor shaft is 3mm. During the experiment, the width ratio of the first oil trace to the second oil trace was 1.3:1. In this example, a speed-boosting component is further added so that when the set spacing L is 3mm, the width ratio of the first oil trace to the second oil trace is close to 1, which means that a better oil balance effect can be achieved.

[0042] In this invention, unless otherwise explicitly specified or limited in the embodiments, the terms "installation," "connection," "joining," and "fixing" appearing in the embodiments should be interpreted broadly. For example, a connection can be a fixed connection, a detachable connection, or an integral part; it can also be a mechanical connection, an electrical connection, etc. Of course, it can also be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components, or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific implementation.

[0043] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A motor shaft, comprising a shaft body (1), wherein the shaft body (1) is provided with an oil supply channel (10) along its axial direction, the oil supply channel (10) having an oil inlet (100), and the shaft body (1) is provided with an oil injection hole along its radial direction communicating the oil supply channel (10) with the outside, the oil injection hole comprising a first oil injection hole (11) and a second oil injection hole (12) arranged at intervals along the axial direction of the shaft body (1), and the first oil injection hole (11) being located between the oil inlet (100) and the second oil injection hole (12); characterized in that, The oil delivery channel (10) includes an oil guiding section (101) and an oil supply section (102) that are interconnected. The diameter of the oil guiding section (101) is smaller than that of the oil supply section (102) to form an oil guiding step (13) for allowing a portion of the cooling oil to flow directly to the second oil injection hole (12) through the first oil injection hole (11). The oil guiding step (13) is located between the oil inlet (100) and the first oil injection hole (11), and the oil guiding step (13) has a set height. The oil guiding step (13) and the first oil injection hole (11) have a set distance, which is a selected value between 1 mm and 50 mm. The oil guide section (101) is provided with a speed-increasing component (14) for increasing the flow rate of cooling oil. The size of the speed-increasing component (14) increases uniformly along the axial direction of the shaft (1). The speed-increasing component (14) includes a booster shaft (140) and at least two booster plates (141) formed on the booster shaft (140) along the axial direction of the booster shaft (140), and the booster plates (141) are uniformly distributed along the circumference of the booster shaft (140).

2. The motor shaft as described in claim 1, characterized in that, The set spacing is a selected value between 2mm and 15mm.

3. The motor shaft as described in claim 1 or 2, characterized in that, The minimum diameter of the first injection hole (11) is smaller than the minimum diameter of the second injection hole (12).

4. The motor shaft as described in claim 3, characterized in that, The first injection hole (11) and the second injection hole (12) are both round holes. The first injection hole (11) includes an inner hole section (110) and an outer hole section (111) that are connected to each other. The diameter of the outer hole section (111) and the diameter of the second injection hole (12) are both larger than the diameter of the inner hole section (110).

5. A drive motor, comprising a rotor core (2), characterized in that, It also includes a motor shaft as described in any one of claims 1 to 4, wherein the rotor core (2) is positioned on the outer ring of the motor shaft, and the rotor core (2) is provided with a first cooling oil passage (21) and a second cooling oil passage (22), wherein the first cooling oil passage (21) is connected to the oil delivery channel (10) through a first oil injection hole (11), and the second cooling oil passage (22) is connected to the oil delivery channel (10) through a second oil injection hole (12).

6. The drive motor as described in claim 5, characterized in that, The rotor core (2) is formed by stacking multiple rotor laminations. Both ends of the rotor core (2) are provided with rotor end plates (3) for reinforcing the rotor laminations. The end face of the rotor end plate (3) facing the rotor core (2) is provided with a groove (30). The end face of the rotor core (2) cooperates with the groove (30) to form a connecting channel (20). The first cooling oil passage (21) is connected to the first oil injection hole (11) through the connecting channel (20). The second cooling oil passage (22) is connected to the second oil injection hole (12) through the connecting channel (20).

7. A new energy vehicle, characterized in that, Includes the drive motor as described in claim 5 or 6.

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