Rotor assembly and motor

Abstract

This utility model provides a rotor assembly and a motor; the motor includes a stator assembly and a rotor assembly; the rotor assembly includes: a rotor shaft, one end of which is an oil inlet communicating with an oil inlet chamber of the rotor shaft, the oil inlet chamber extending axially from the oil inlet to a position corresponding to the middle of the rotor core, the end of the oil inlet chamber away from the oil inlet being a closed end, and at least one set of oil holes being provided on the cavity wall of the oil inlet chamber near the closed end, with multiple oil outlet holes in the at least one set of oil holes spaced circumferentially; a rotor core, fitted onto the rotor shaft through an inner hole; a squirrel cage, circumferentially disposed on the rotor core; and cooling oil channels, radially located between the inner hole of the rotor core and the outer side of the rotor shaft, with multiple cooling oil channels spaced circumferentially, each cooling oil channel extending axially and at least to both axial ends of the rotor core, each cooling oil channel communicating with the oil inlet chamber through at least one oil outlet hole. This configuration improves cooling effect and efficiency while reducing processing difficulty and cost.

Description

Technical Field

[0001] This utility model relates to the field of motor manufacturing technology, specifically to a rotor assembly and a motor. Background Technology

[0002] As the power component of new energy vehicles, the electric motor generates torque to drive the vehicle. Induction asynchronous motors, as a type of electric motor, are increasingly widely used in automotive drive motors due to their lower cost and excellent high-speed efficiency. The rotor of an induction asynchronous motor typically consists of three parts: a rotor core 1, a squirrel cage 2, and a shaft 3, as detailed below. Figure 1 As shown, the squirrel cages 2 form parallel circuits that cut into the alternating magnetic field of the motor stator, generating an induced electromotive force and creating a magnetic field asynchronous with the stator's magnetic field, thus causing the rotor to generate torque. Since the squirrel cages 2 carry current during operation, they generate a large amount of heat, and the rotor's performance and efficiency drop significantly after heating up, resulting in insufficient continuous operation of the induction motor. Therefore, rotor cooling is necessary. The conventional cooling method involves introducing cooling oil into the shaft 3 and then slinging the oil through oil holes 4 on the shaft 3 to directly cool the end rings 5 ​​at both ends of the squirrel cage 2. This method involves oil entering from one end of the shaft 3 and opening oil holes 4 at positions corresponding to the end rings 5. The oil holes 4 closer to the inlet on the shaft 3 have a higher flow rate, while those farther away have a lower flow rate or even no flow. This causes uneven cooling of the end rings 5 ​​at both ends of the rotor, especially noticeable at high speeds, thus affecting motor performance. Furthermore, this cooling method only cools the end rings 5 ​​and cannot directly cool the internal guide bars and rotor core 1; it only provides indirect cooling through the end rings 5, resulting in poor cooling effect and low cooling efficiency. Utility Model Content

[0003] The purpose of this utility model is to provide a rotor assembly and motor, which distributes cooling medium from the middle of the rotor core to both ends of the rotor core to fully cool the rotor core and internal guide bars, while also cooling the end rings at both ends. This allows all parts of the rotor assembly to be fully cooled, improving the rotor cooling effect and efficiency, while also simplifying the structure and reducing the processing difficulty and cost.

[0004] To achieve the above objectives, this utility model provides a rotor assembly, comprising:

[0005] The rotor shaft has an oil inlet at one end, which is connected to the oil inlet chamber of the rotor shaft. The oil inlet chamber extends from the oil inlet along the axial direction of the rotor shaft to a position corresponding to the middle of the rotor core. The end of the oil inlet chamber away from the oil inlet is a closed end. At least one set of oil holes is provided on the cavity wall of the oil inlet chamber near the closed end. Multiple oil outlet holes in the at least one set of oil holes are arranged at intervals along the circumference of the rotor shaft.

[0006] The rotor core is fitted onto the rotor shaft through an inner hole;

[0007] A squirrel cage, arranged in a ring around the rotor core; and,

[0008] The cooling oil passages are radially located between the inner hole of the rotor core and the outer side of the rotor shaft. A plurality of cooling oil passages are distributed circumferentially along the rotor assembly. Each cooling oil passage extends axially along the rotor assembly and extends at least to both axial ends of the rotor core. Each cooling oil passage communicates with the oil inlet chamber through at least one oil outlet hole.

[0009] Optionally, the plurality of cooling oil passages are symmetrically distributed circumferentially along the rotor assembly and symmetrically distributed axially along the rotor assembly.

[0010] Optionally, there are 2 to 4 cooling oil channels.

[0011] Optionally, the length of the cooling oil passage extending axially along the rotor assembly is greater than or equal to the length of the rotor core.

[0012] Optionally, at least one set of oil holes has multiple oil outlet holes symmetrically distributed circumferentially along the rotor shaft, and / or, the wall of the oil inlet chamber is provided with multiple sets of oil holes, the multiple sets of oil holes are spaced apart axially along the rotor shaft, and at least part of the cooling oil passages are connected to the oil inlet chamber through the multiple oil outlet holes spaced apart axially.

[0013] Optionally, all of the cooling oil channels are disposed on the inner wall of the rotor core, and each cooling oil channel extends axially to both ends of the rotor core; or, all of the cooling oil channels are disposed on the outer circumferential surface of the rotor shaft, and each cooling oil channel extends axially beyond both ends of the rotor core.

[0014] Optionally, the inner hole of the rotor core is interference-fitted with the outer circumferential surface of the rotor shaft.

[0015] Optionally, a plurality of cooling oil channels are provided at intervals along the circumference of the rotor core on the inner hole wall of the rotor core, and a plurality of cooling oil channels are provided at intervals along the circumference of the rotor shaft on the outer circumference surface of the rotor shaft. The plurality of cooling oil channels on the outer circumference surface of the rotor shaft extend axially beyond the two ends of the rotor core, and the plurality of cooling oil channels on the inner hole wall extend axially to the two ends of the rotor core.

[0016] Optionally, the rotor assembly also has at least one of the following structures:

[0017] The inner hole of the rotor core is interference-fitted with the outer circumferential surface of the rotor shaft;

[0018] The number of cooling oil channels on the inner hole wall may be the same as or different from the number of cooling oil channels on the outer circumference of the rotor shaft.

[0019] The circumferential position of the cooling oil passages on the inner bore wall may be the same as or different from the circumferential position of the cooling oil passages on the outer circumferential surface of the rotor shaft.

[0020] Furthermore, to achieve the above objectives, this utility model also provides an electric motor, including a stator assembly and the rotor assembly disposed inside the stator assembly.

[0021] The rotor assembly and motor provided by this utility model include a rotor shaft with an oil inlet at one end, the oil inlet communicating with an oil inlet chamber of the rotor shaft, the oil inlet extending from the oil inlet along the axial direction of the rotor shaft to a position corresponding to the middle of the rotor core, the end of the oil inlet chamber away from the oil inlet being a closed end, at least one set of oil holes being provided on the cavity wall of the oil inlet near the closed end, and a plurality of oil outlet holes in the at least one set of oil holes being spaced apart circumferentially along the rotor shaft; a rotor core being fitted onto the rotor shaft through an inner hole; a squirrel cage being circumferentially disposed on the rotor core; and cooling oil channels being radially located between the inner hole of the rotor core and the outer side of the rotor shaft, a plurality of cooling oil channels being spaced apart circumferentially along the rotor assembly, each cooling oil channel extending axially along the rotor assembly and extending at least to both axial ends of the rotor core, each cooling oil channel communicating with the oil inlet chamber through at least one oil outlet hole. This configuration allows the cooling medium to flow through the rotor shaft to the center of the rotor core, and then, starting from the center, is bidirectionally distributed to both ends of the rotor core via multiple circumferentially distributed cooling channels. Finally, centrifugal force evenly covers the end rings at both ends. This structural design ensures that all parts of the rotor assembly are adequately and uniformly cooled, improving the overall cooling effect and efficiency of the rotor assembly, and enhancing motor performance. Furthermore, the use of cooling oil channels between the inner bore of the rotor core and the outer side of the rotor shaft simplifies the structure and reduces manufacturing difficulty and cost. Attached Figure Description

[0022] The accompanying drawings are provided to better understand this utility model and do not constitute an undue limitation thereof. Wherein:

[0023] Figure 1 This is a schematic diagram of the rotor structure of an induction asynchronous motor in the prior art;

[0024] Figure 2 This is a three-dimensional structural schematic diagram of a rotor assembly provided according to an embodiment of the present invention;

[0025] Figure 3 yes Figure 2 Side view of the rotor assembly

[0026] Figure 4 This is a top view of the rotor core provided according to an embodiment of the present invention;

[0027] Figure 5 This is a three-dimensional structural schematic diagram of the rotor core provided according to an embodiment of the present invention;

[0028] Figure 6 This is a schematic diagram of the axial cross-section of a rotor assembly provided according to an embodiment of the present invention, wherein the arrows in the diagram indicate the flow direction of the cooling medium;

[0029] Figure 7 This is a schematic diagram of the first cooling method provided by this utility model according to an embodiment, where the arrows indicate the flow direction of the cooling medium;

[0030] Figure 8 This is a side view of the rotor shaft provided according to an embodiment of the present invention;

[0031] Figure 9 This is a schematic diagram of the axial cross-section of a rotor assembly provided according to another embodiment of the present invention, wherein the arrows in the diagram indicate the flow direction of the cooling medium;

[0032] Figure 10 This is a schematic diagram of the second cooling method provided by this utility model according to an embodiment. The arrows in the diagram indicate the flow direction of the cooling medium.

[0033] Figure 11 This is a schematic diagram of the axial cross-section of a rotor assembly provided according to another embodiment of the present invention, wherein the arrows in the diagram indicate the flow direction of the cooling medium.

[0034] [ Figure 2-11 The reference numerals in the attached drawings are explained as follows: 100-rotor assembly, 101-rotor shaft, 1011-oil inlet, 1012-oil inlet chamber, 1013-oil outlet, 102-rotor core, 1021-guide bar groove, 1022-inner hole, 103-squirrel cage, 1031-end ring, 1032-guide bar, 104-cooling oil passage, 110-axial clearance. Detailed Implementation

[0035] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model. It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of this utility model. Therefore, the drawings only show components related to this utility model and are not drawn according to the actual number, shape, and size of the components in implementation. In actual implementation, the type, quantity, and proportion of each component can be arbitrarily changed, and the component layout may also be more complex.

[0036] Furthermore, while each embodiment described below possesses one or more technical features, this does not imply that users of this utility model must simultaneously implement all technical features in any embodiment, or can only separately implement some or all technical features in different embodiments. In other words, provided it is feasible, those skilled in the art can, based on the disclosure of this utility model and depending on design specifications or actual needs, selectively implement some or all technical features in any embodiment, or selectively implement a combination of some or all technical features in multiple embodiments, thereby increasing the flexibility in implementing this utility model.

[0037] As used herein, the singular forms “a,” “an,” and “the” include plural objects, and the plural form “a plurality” includes two or more objects, unless otherwise expressly indicated. As used herein, the term “or” is generally used to include the meaning of “and / or,” unless otherwise expressly indicated, and the terms “install,” “connect,” and “link” should be interpreted broadly, for example, as a fixed connection, a detachable connection, or an integral connection. Connections can be mechanical or electrical. Connections can be direct or indirect through an intermediate medium, and can represent internal communication between two elements or an interaction between two elements. Relational terms such as “first,” “second,” etc., are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations, nor do they indicate relative importance or implicitly specify the number of indicated technical features. Those skilled in the art will understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0038] One of the objectives of this invention is to provide a rotor assembly that distributes cooling medium from the middle of the rotor core toward both ends of the rotor core to fully cool the rotor core and internal guide bars, while also cooling the end rings at both ends.

[0039] The second objective of this invention is to provide an electric motor that uses the rotor assembly provided by this invention. By improving the structure of the rotor assembly, the cooling effect and efficiency are improved while the cooling architecture is simplified, thereby reducing the processing difficulty and manufacturing cost.

[0040] To make the objectives, advantages, and features of this utility model clearer, the following detailed description is provided in conjunction with the accompanying drawings. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clearly illustrate the objectives of the embodiments of this utility model.

[0041] Figure 2 This is a three-dimensional structural schematic diagram of the rotor assembly 100 according to an embodiment of the present invention. Figure 3 yes Figure 2 Side view of the rotor assembly 100.

[0042] like Figure 2 and Figure 3 As shown, the rotor assembly 100 includes a rotor shaft 101, a rotor core 102, and a squirrel cage 103. The squirrel cage 103 is arranged around the rotor core 102 and includes two opposing end rings 1031 and a plurality of guide bars 1032 located between the two end rings 1031. The guide bars 1032 extend along the axial direction of the rotor core 102 and are distributed circumferentially at intervals. Generally, the guide bars 1032 and the two end rings 1031 are cast together, but the actual material is not limited to this. The material of the squirrel cage 103 includes, but is not limited to, aluminum, and may also be copper or other commonly used conductive materials. The two ends of the guide bars 1032 are respectively connected to the two end rings 1031, which are located at the two axial ends of the rotor core 102 and are in close contact with the rotor core 102.

[0043] Figure 4 This is a top view of the rotor core 101 according to an embodiment of the present invention. Figure 5 This is a three-dimensional structural diagram of the rotor core 102 provided according to an embodiment of the present invention.

[0044] like Figure 4 and Figure 5As shown, the rotor core 102 is a cylinder with several guide bar grooves 1021 on its outer edge. These grooves extend axially along the rotor core 102 and are spaced apart circumferentially. Thus, several guide bars 1032 are inserted one-to-one into the guide bar grooves 1021. It should be noted that although the guide bar grooves 1021 shown in the figure are laterally open, they can be closed in other cases; this is not a limitation. The number of guide bar grooves 1021 used is determined according to the performance requirements of the motor.

[0045] Those skilled in the art will understand that the rotor core 102 may include multiple core laminations, which are stacked sequentially along the axial direction. Non-limitingly, the multiple core laminations are rotated and misaligned; after rotational misalignment, the guide grooves 1021 at different axial positions are circumferentially misaligned, forming... Figure 5 The rotor core 102 shown is equipped with skewed poles. It should be noted that the skewed poles can be straight or other skewed pole forms, such as V-type, etc., and there is no limitation on this.

[0046] Figure 4 and Figure 5 In this design, the rotor core 102 has an inner hole 1022, and is fitted onto the rotor shaft 101 through the inner hole 1022. The basic shape of the inner hole 1022 of the rotor core 102 is circular. It should be noted that the rotor core 102 and the rotor shaft 101 can be assembled and fixed in various ways, such as the more common keyway fit and interference fit.

[0047] like Figures 4 to 11 As shown in various embodiments of this application, the rotor assembly 100 further includes cooling oil channels 104, which are radially located between the inner hole 1022 of the rotor core 102 and the outer side of the rotor shaft 101. This configuration simplifies the cooling architecture, reduces the processing difficulty and manufacturing cost of the rotor assembly 100, that is, it designs the cooling structure in the simplest and easiest way to implement, and ensures that all parts of the rotor assembly 100 are sufficiently and uniformly cooled. There are multiple cooling oil channels 104, and the multiple cooling oil channels 104 are distributed circumferentially around the rotor assembly 100. Each cooling oil channel 104 extends axially along the rotor assembly 100 and extends at least to both axial ends of the rotor core 102.

[0048] Secondly, the oil inlet method was optimized. The rotor shaft 101 was configured with one end as an oil inlet 1011, which communicates with the oil inlet chamber 1012 inside the rotor shaft 101. The oil inlet chamber 1012 extends from the oil inlet 1011 along the axial direction of the rotor shaft 101 to a position corresponding to the middle of the rotor core 102. At this time, the end of the oil inlet chamber 1012 away from the oil inlet 1011 is the closed end (not connected to the outside). At the same time, at least one set of oil holes is provided on the cavity wall of the oil inlet chamber 1012 near the closed end. Multiple oil outlet holes 1013 in the at least one set of oil holes are arranged at intervals along the circumference of the rotor shaft 101. It should be noted that the at least one set of oil holes is located on the rotor shaft 101 corresponding to the middle of the rotor core 102, which allows the cooling medium to flow directly into the middle of the rotor core 102 after flowing out from the oil outlet holes 1013. Here, the center of the rotor core 102 refers to the exact middle position. However, considering potential manufacturing and assembly errors, the center of the rotor core 102 may also be slightly to the left or right. In short, at least one set of oil holes should be positioned relatively centrally relative to the rotor core 102.

[0049] Thus, each cooling oil passage 104 is connected to the oil inlet chamber 1012 of the rotor shaft 101 through at least one oil outlet 1013, ensuring that the cooling medium entering the rotor shaft 101 continuously flows into the multiple cooling channels 104. Furthermore, by releasing the cooling medium at the middle position of the rotor core 102, the cooling medium is bidirectionally diverted from the middle of the rotor core 102 through the multiple circumferentially distributed cooling channels 104 to both ends of the rotor core 102, and finally evenly covers the end rings 1031 at both ends through centrifugal force. This design allows for sufficient and uniform cooling of all parts of the rotor assembly 100, improving cooling effect and efficiency, and enhancing motor performance.

[0050] Preferably, the multiple cooling oil channels 104 are symmetrically distributed circumferentially along the rotor assembly 100 and symmetrically distributed axially along the rotor assembly 100. This arrangement improves cooling efficiency, reduces temperature unevenness, and provides better cooling effect. It also helps to balance mechanical forces and reduce vibration and noise during motor operation.

[0051] The number of cooling oil channels 104 is adjusted according to actual conditions. Further, to simplify design and manufacturing, the cooling oil channels 104 are preferably two to four. For example, in this embodiment, the cooling oil channels 104 are set to three or four, with the three cooling oil channels 104 arranged symmetrically at 120°, or the four cooling oil channels 104 arranged symmetrically at 90°. Alternatively, the cooling oil channels 104 can be two, arranged symmetrically at 180°. The cooling oil channels 104 can be arranged parallel to the axis of the rotor core 102, or they can be opposite to the axis of the rotor core 102. Generally, by rotating and misaligning the installation, the cooling oil channels 104 are arranged opposite to the axis of the rotor core 102; conversely, the cooling oil channels 104 are arranged parallel to the axis of the rotor core 102.

[0052] In some embodiments, the length of the cooling oil passage 104 extending axially along the rotor assembly 100 is equal to the length of the rotor core 102. In this case, all cooling oil passages 104 are disposed on the inner wall of the inner bore 1022 of the rotor core 102, and each cooling oil passage 104 extends axially along the rotor core 102 to both axial ends of the rotor core 102, specifically as follows: Figure 4 and Figure 5 As shown. Compared to opening holes inside the rotor core 102, this structure is simpler and easier to process, which helps to reduce processing difficulty and manufacturing costs. Thus, by stamping notches into the inner wall of each core lamination, and stacking multiple core laminations, the circumferential positions of the notches of each core lamination correspond and connect, thereby forming the cooling oil channel 104.

[0053] In this case, preferably, the wall between any two adjacent cooling oil passages 104 on the inner hole 1022 serves as the mounting surface of the rotor core 102. By interfering with the rotor shaft 101 through the mounting surface of the rotor core 102, the relative fixation of the rotor core 102 and the rotor shaft 101 can be achieved. This configuration ensures proper assembly and fixation between the rotor shaft 101 and the rotor core 102, and is simpler and more convenient than the keyway assembly method.

[0054] This application does not impose any special limitation on the cross-sectional shape of the cooling oil channels 104 on the wall of the inner hole 1022, as long as it is convenient for processing. For example, in this embodiment, the cross-sectional shape of each cooling oil channel 104 is semi-circular. In addition, other hole shapes such as triangles, rectangles, or other hole shapes that are convenient for stamping are also suitable. Circular holes and square holes are the most suitable. In short, the notches on the wall of the inner hole 1022 are suitable for stamping due to their symmetry and uniformity, or their regular geometric shape and uniform stress characteristics. Of course, this application does not exclude the use of irregular geometric shapes for the cooling channels 104.

[0055] Figure 4 and Figure 5 In one exemplary embodiment described, there are three cooling oil channels 104 on the wall of the inner hole 1022. The three cooling oil channels 104 are symmetrically arranged at 120°, and the cross-sectional shape of each cooling oil channel 104 is semi-circular. When multiple core laminations are installed in a misaligned manner along the axial direction, the three cooling oil channels 104 are all in a twisted state and are not parallel to the axis of the rotor core 102. Although the notches on the inner holes of each core lamination are circumferentially misaligned, they still overlap and connect circumferentially. At this time, the cooling oil channels 104 are stepped oil channels.

[0056] Combination Figure 6 and Figure 7 The first cooling method will be further explained below. For example... Figure 6 and Figure 7 As shown, from an axial cross-section, the cooling medium enters the oil inlet chamber 1012 from the oil inlet 1011 at one end of the rotor shaft 101. After reaching the closed end of the oil inlet chamber 1012, it turns and flows through the oil outlet 1013 into the inner hole 1022 in the middle of the rotor core 102. Then, starting from the middle of the rotor core 102, it is bidirectionally distributed to both ends of the rotor core 102 through multiple axially and circumferentially symmetrical cooling oil channels 104. In this process, the cooling medium exchanges heat with the rotor core 102, cooling not only the rotor core 102 but also the guide bars 1032. Finally, after reaching the end face of the rotor core 102, due to the centrifugal force of the rotor rotation, the cooling medium is thrown to the inner side of the end ring 1031 and evenly covers it, continuing to cool the end ring 1031.

[0057] It should be understood that the cooling medium is cooling oil, which is insulating and can enter the stator and rotor, thus providing a good cooling effect.

[0058] In another embodiment, the length of the cooling oil passage 104 extending axially along the rotor assembly 100 is greater than the length of the rotor core 102. Accordingly, all cooling oil passages 104 are arranged on the outer circumferential surface of the rotor shaft 101, and each cooling oil passage 104 extends axially beyond both ends of the rotor core 102 along the rotor shaft 101. Figure 8 As shown, the outer circumferential surface of the rotor shaft 101 is machined to form a groove, which constitutes a cooling channel 104. The groove is machined by milling and machining, which is convenient. At this time, the cooling oil channel 104 extends beyond the rotor core 102 at both ends along the axial direction, forming an axial gap 110, so that the cooling medium reaches both ends of the rotor core 102 and is thrown into the end rings 1031 at both ends through the axial gaps 110.

[0059] Combination Figure 9 and Figure 10 The second cooling method will be further explained below. For example... Figure 9 and Figure 10As shown, viewed from the axial section of the rotor assembly 100, the cooling medium flows from the oil inlet 1011 at one end of the rotor shaft 101 into the oil inlet chamber 1012. After reaching the closed end of the oil inlet chamber 1012, it turns and flows through the oil outlet 1013 into the cooling oil channel 104 on the outer circumferential surface of the rotor shaft 101. Then, starting from the middle position of the cooling oil channel 104 corresponding to the middle position of the rotor core 102, it is bidirectionally split to both ends of the rotor core 102 through multiple axially and circumferentially symmetrical cooling oil channels 104. This process is similar to the principle of the first cooling method. The cooling medium exchanges heat with the rotor core 102, cooling the rotor core 102 and the guide bars 1032. Finally, after reaching the end face of the rotor core 102, it is thrown to the inner side of the end ring 1031 through the axial gap 110 under the action of the centrifugal force of the rotor rotation, cooling the end ring 1031.

[0060] It should be noted that in the first cooling method, cooling oil channels 104 are not provided on the outer circumferential surface of the rotor shaft 101. When the inner hole 1022 of the rotor core 102 is interference-fitted with the rotor shaft 101, the machining of keyways on the rotor shaft 101 is avoided, which simplifies the structure of the rotor shaft 101 and reduces the manufacturing cost of the rotor shaft 101. In addition, in the second cooling method, cooling oil channels 104 are not provided on the wall of the inner hole 1022 of the rotor core 102. Preferably, the outer circumferential surface between any two adjacent cooling oil channels 104 on the outer circumferential surface of the rotor shaft 101 is used as the assembly surface of the rotor shaft 101. The relative fixation of the rotor core 102 and the rotor shaft 101 is achieved by the interference fit between the assembly surface of the rotor shaft 101 and the inner hole 1022 of the rotor core 102, replacing the traditional keyway and key fit method.

[0061] Similarly, this application does not impose any particular limitation on the shape of the cooling oil passage 104 on the outer circumferential surface of the rotor shaft 101, as long as it is convenient to process. For example, the shape of the cooling oil passage 104 may be triangular, trapezoidal, rectangular, or semi-circular, etc., and can be adjusted and set according to actual needs.

[0062] Figure 9 In one exemplary embodiment described, grooves are provided at 120° intervals on the outer circumferential surface of the rotor shaft 101 to form three cooling oil passages 104, and each groove has an oil outlet 1013 at its central position.

[0063] Figure 10 In another exemplary embodiment described, grooves are provided at 90° intervals on the outer circumferential surface of the rotor shaft 101 to form four cooling oil passages 104, and each groove has an oil outlet 1013 at its central position.

[0064] Therefore, even if the cooling oil passage 104 is set on the rotor shaft 101, the cooling medium can be distributed from the middle of the rotor core 101 to both ends of the rotor core 102, ensuring that the cooling medium is evenly distributed and that all parts of the rotor assembly 100 can be fully cooled.

[0065] The first and second cooling methods described above can be used individually or in combination. When used in combination, such as... Figure 11 As shown. Figure 11 In this embodiment, the number and position of the cooling oil channels 104 on the rotor shaft 101 are consistent with those on the rotor core 102, and both are connected to the oil inlet chamber 1012 through corresponding oil outlet holes 1013. However, in other embodiments, the number of cooling oil channels 104 on the rotor shaft 101 may differ from that on the rotor core 102; for example, the rotor core 102 may have more or fewer cooling channels 104. The circumferential position of the cooling oil channels 104 on the rotor shaft 101 may be different from or the same as that on the rotor core 102. Compared to a single cooling method, a combined cooling method is more suitable for high-flow-rate cooling requirements.

[0066] Those skilled in the art should understand that regardless of the cooling method, cooling oil can flow along the outer circumferential surface of the rotor shaft 101, thereby simplifying the structure, reducing processing difficulty and manufacturing costs, while ensuring sufficient and uniform cooling of all parts of the rotor assembly 100.

[0067] The cooling process for the rotor assembly 100 provided in this application can be as follows:

[0068] (1) The oil pump introduces cooling oil into the oil inlet chamber 1012 of the rotor shaft 101. The rotor shaft 101 has multiple oil outlet holes 1013 at its center position. The cooling oil enters the middle part of the rotor core 101 through the oil outlet holes 1013. In this process, it is necessary to ensure that the cooling oil can reach the center position of the rotor shaft 101 and has sufficient pressure difference to pump into the cooling oil passage 104 between the rotor core 102 and the rotor shaft 101.

[0069] (2) After entering the middle of the rotor core 102, the cooling oil is divided into two branches, which flow to both ends of the rotor core 102 respectively, ensuring that the amount of oil at both ends of the rotor core 101 is the same. It should be noted that the cross-sectional dimensions of the cooling oil passage 104 can be designed according to the actual cooling oil flow rate, rotor heat generation and rotor size to avoid the situation where the oil speed is too fast due to the space of the cooling oil passage 104 being too small, or the oil filling and cooling is uneven due to the space of the cooling oil passage 104 being too large.

[0070] (3) When the cooling oil fills each cooling oil passage 104, it continues to flow along the cooling oil passage 104 toward the end of the rotor core 102. When it flows through the adjacent rotor core 102, it exchanges heat and cools, indirectly carrying away the heat of the guide bar 1032.

[0071] (4) After the cooling oil reaches the end of the rotor core 102, it flows radially out through the centrifugal force generated by the rotor rotation to the inner side of the end ring 1031. The oil after cooling the end ring 1031 continues to flow to the stator winding, reducing the temperature of the stator winding.

[0072] Unlike conventional cooling methods, the rotor assembly 100 of this application is equipped with bidirectional oil channels to ensure uniform cooling and the same amount of oil on both sides of the rotor, resulting in a consistent temperature field and good cooling effect. Furthermore, the manufacturing process is simple, allowing for stamping, machining, and other methods. This simplifies processing, reduces costs, and eliminates the need for the complex oil channel structure required for S-shaped cooling, significantly lowering the difficulty and cost of motor manufacturing.

[0073] Furthermore, it is preferable that the multiple oil outlet holes 1013 in at least one set of oil holes are symmetrically distributed along the circumference of the rotor shaft 101, which can ensure that the cooling oil can be evenly distributed during motor operation, thereby improving the operating efficiency and reliability of the motor. The symmetrical arrangement can also simplify the oil circuit and balance the force on the rotor shaft 101.

[0074] In some embodiments, only one set of oil holes is provided, and each cooling oil passage 104 is connected to the oil inlet chamber 1012 of the rotor shaft 101 through only one oil outlet 1013, thereby simplifying the machining of the rotor shaft 101. In other embodiments, multiple sets of oil holes are provided on the cavity wall of the oil inlet chamber 1012, and the multiple sets of oil holes are spaced apart along the axial direction of the rotor shaft 101. In this case, at least some of the cooling oil passages 104 are connected to the oil inlet chamber 1012 of the rotor shaft 101 through multiple oil outlets 1013 distributed axially. That is, a cooling oil passage 104 is connected to the oil inlet chamber 1012 of the rotor shaft 101 through at least two oil outlets 1013 distributed axially, thereby increasing the oil inlet speed and improving the cooling efficiency.

[0075] Furthermore, this application embodiment also provides a motor, which is provided with the rotor assembly 100 described in any embodiment of this application. The motor in this application embodiment is an induction asynchronous motor, which can be applied to new energy vehicles and used as a drive motor. Those skilled in the art should understand that the motor in this application embodiment also includes a stator assembly, and the rotor assembly 100 is coaxially sleeved inside the stator assembly. The rotor assembly 100 and the stator assembly are assembled together to form a stator-rotor assembly, which is installed inside the motor housing.

[0076] Furthermore, Table 1 below provides a comparison of the cooling effects under different cooling methods. It is evident that, under different cooling methods, the cooling effect of the proposed solution is significantly superior to rotor air cooling, end ring direct cooling, and S-type reciprocating cycle cooling. This is because the temperature consistency at both ends of the squirrel cage 103 is good, resulting in a better cooling effect. Therefore, any cooling solution adopted in this application can significantly improve the motor's cooling and heat dissipation capacity, enhance the motor's continuous operation performance, and improve the motor's reliability.

[0077] Table 1: Cooling effect under different cooling methods

[0078]

[0079] In summary, this application can effectively reduce the temperature of the rotor squirrel cage in an electric motor, and has at least the following beneficial effects:

[0080] With a dual-path oil channel design (one-to-two), the oil directly cools the rotor core 102 and indirectly cools the guide bars 1032, effectively reducing the motor temperature. Therefore, the cooling oil quickly removes heat from critical heat-generating components, achieving efficient heat dissipation. It also maximizes temperature uniformity at both ends of the rotor, avoiding uneven temperature fields caused by excessively long and winding oil channels leading to large temperature differences between the inlet and outlet oil. This reduces the impact of thermal stress on the motor structure, improving the motor's reliability and operational stability. Furthermore, the cooling method is easy to design and control. The cooling oil flows from the rotor core 102 end face to the stator windings, effectively reducing the temperature at the stator winding ends and protecting them. The stator windings are the part of the motor that generates the most heat; by reducing their temperature, the motor's continuous performance is improved, reducing malfunctions caused by overheating.

[0081] Finally, it should be noted that although the accompanying drawings illustrate a rotor assembly 100 with 66 guide slots 1021, this is merely one embodiment of the present invention and does not constitute a limitation on the scope of protection of the present invention. Furthermore, the number of poles in the motor is not limited; 4, 6, 8, 12, or other pole numbers are all acceptable. In addition to the parts / structures described in the above embodiments, those skilled in the art can easily configure other related parts / structures for the rotor assembly 100 based on existing technology, such as core end shoulders, balance discs, interference rings, and locking rings. These are easily implemented by those skilled in the art based on existing technology and will not be described further. Moreover, the multiple cooling oil channels 104 are all independent and not interconnected, ensuring that the cooling medium is evenly distributed in each cooling oil channel 104, avoiding uneven cooling and reducing the complexity of the cooling design.

[0082] While the present invention has been disclosed above, it is not limited thereto. Those skilled in the art can make various modifications and variations to the present invention without departing from its spirit and scope. Therefore, if such modifications and variations fall within the scope of this specification and its equivalents, the present invention also intends to include such modifications and variations.

Claims

1. A rotor assembly characterized by, include: The rotor shaft has an oil inlet at one end, which is connected to the oil inlet chamber of the rotor shaft. The oil inlet chamber extends from the oil inlet along the axial direction of the rotor shaft to a position corresponding to the middle of the rotor core. The end of the oil inlet chamber away from the oil inlet is a closed end. At least one set of oil holes is provided on the cavity wall of the oil inlet chamber near the closed end. Multiple oil outlet holes in the at least one set of oil holes are arranged at intervals along the circumference of the rotor shaft. The rotor core is fitted onto the rotor shaft through an inner hole; A squirrel cage, arranged in a ring around the rotor core; and, The cooling oil passages are radially located between the inner hole of the rotor core and the outer side of the rotor shaft. A plurality of cooling oil passages are distributed circumferentially along the rotor assembly. Each cooling oil passage extends axially along the rotor assembly and extends at least to both axial ends of the rotor core. Each cooling oil passage communicates with the oil inlet chamber through at least one oil outlet hole.

2. The rotor assembly of claim 1, wherein The plurality of cooling oil passages are symmetrically distributed circumferentially along the rotor assembly and symmetrically distributed axially along the rotor assembly.

3. The rotor assembly of claim 2, wherein, The number of cooling oil channels is 2 to 4.

4. The rotor assembly of claim 1, wherein The length of the cooling oil passage extending axially along the rotor assembly is greater than or equal to the length of the rotor core.

5. The rotor assembly of claim 1, wherein At least one set of oil holes has multiple oil outlet holes symmetrically distributed circumferentially along the rotor shaft, and / or, the wall of the oil inlet chamber is provided with multiple sets of oil holes, the multiple sets of oil holes are spaced apart axially along the rotor shaft, and at least part of the cooling oil passages are connected to the oil inlet chamber through multiple oil outlet holes spaced apart axially.

6. The rotor assembly of claim 1, wherein All of the cooling oil channels are provided on the inner wall of the rotor core, and each cooling oil channel extends axially to both ends of the rotor core. Alternatively, all of the cooling oil channels are provided on the outer circumferential surface of the rotor shaft, and each cooling oil channel extends axially beyond both ends of the rotor core.

7. The rotor assembly of claim 6, wherein The inner hole of the rotor core is interference-fitted with the outer circumferential surface of the rotor shaft.

8. The rotor assembly of claim 1, wherein Multiple cooling oil channels are spaced apart along the circumference of the rotor core on the inner wall of the rotor core. At the same time, multiple cooling oil channels are spaced apart along the circumference of the rotor shaft on the outer circumference of the rotor shaft. The multiple cooling oil channels on the outer circumference of the rotor shaft extend axially beyond the two ends of the rotor core. The multiple cooling oil channels on the inner wall of the rotor core extend axially to the two ends of the rotor core.

9. The rotor assembly of claim 8, wherein, The rotor assembly also has at least one of the following structures: The inner hole of the rotor core is interference-fitted with the outer circumferential surface of the rotor shaft; The number of cooling oil channels on the inner hole wall may be the same as or different from the number of cooling oil channels on the outer circumference of the rotor shaft. The circumferential position of the cooling oil passages on the inner bore wall may be the same as or different from the circumferential position of the cooling oil passages on the outer circumferential surface of the rotor shaft.

10. An electric machine characterized by It includes a stator assembly and a rotor assembly as described in any one of claims 1-9 disposed inside the stator assembly.

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