Rotor assembly and motor including the rotor assembly

Abstract

The present disclosure relates to a rotor assembly and a motor including the rotor assembly. The rotor assembly according to the present disclosure includes: a rotor core having a through hole formed to pass through a central portion thereof in an axial direction of the rotor core; and a rotor shaft coupled to the rotor core through the through hole, and the rotor shaft having a hollow portion into which a cooling fluid is introduced. A heat sink protrudes from an inner circumferential surface of the rotor core toward the rotor shaft to form a rotor cooling channel between the rotor core and the rotor shaft for the cooling fluid to flow.

Description

Technical Field

[0001] The present disclosure relates to a rotor assembly and a motor including the same, and more particularly, to a rotor assembly for improving cooling efficiency of an oil-cooled motor and a motor including the same. Background Art

[0002] The drive motor is configured to generate torque when power is applied thereto and has various structures. For example, a drive motor used in an electric vehicle may include a housing, a stator installed in the housing, and a rotor integrally coupled to a rotating shaft located inside the stator. When current is applied to a stator coil installed in the stator, an induced current is generated in the rotor, and the rotor rotates to generate torque.

[0003] The heat sources of the drive motor are the stator coils through which current flows and the rotor core through which magnetic flux passes. During the operation of the drive motor, when the temperature of the corresponding parts rises excessively, malfunction may occur. Therefore, it is very important to cool the motor to generate heat.

[0004] Methods of cooling a motor that generates heat include an oil cooling method of directly supplying oil to a heat source, a water cooling method of indirectly cooling the heat source by allowing cooling water to flow in a housing passage, and the like.

[0005] In the oil cooling method, a pipe for supplying oil is installed in the housing, and the oil is released from the pipe to directly cool the stator core and the stator coil. The oil cooling method is advantageous in cooling the stator core and the stator coil, but has limitations in directly cooling the rotor core. Therefore, a structure capable of effectively cooling the rotor core in the oil cooling method is required. Summary of the invention

[0006] The present disclosure has solved the above-mentioned problems occurring in the prior art while completely maintaining the advantages achieved by the prior art.

[0007] One aspect of the present disclosure provides a rotor assembly and a motor including the same, which improves cooling performance by implementing a structure capable of directly cooling a rotor core even in an oil cooling method and by forming a rotor cooling channel between a rotor shaft and a rotor core through which a cooling fluid flows.

[0008] Another aspect of the present disclosure provides a rotor assembly and a motor including the rotor assembly, which uses cooling fins to prevent rotation of a rotor core and increases the flow area of ​​a rotor cooling channel by using the fin shape of the cooling fins, thereby increasing the amount of heat transfer and improving the cooling performance of the rotor core.

[0009] The technical problems to be solved by the present disclosure are not limited to the above-mentioned problems, and any other technical problems not mentioned herein will be clearly understood by those skilled in the art to which the present disclosure belongs from the following description.

[0010] According to one aspect of the present disclosure, a rotor assembly includes: a rotor core having a through hole formed to pass through a central portion of the rotor core in an axial direction of the rotor core; and a rotor shaft coupled to the rotor core through the through hole, and the rotor shaft having a hollow portion into which a cooling fluid is introduced. A cooling fin protrudes from an inner circumferential surface of the rotor core toward the rotor shaft to form a rotor cooling channel between the rotor core and the rotor shaft for the cooling fluid to flow.

[0011] The rotor shaft may include: a shaft body in which the hollow portion is formed; an anti-rotation surface formed in a planar shape on at least a portion of an outer surface of the shaft body; and a cooling fluid hole penetrating the shaft body and connecting the hollow portion and the anti-rotation surface to each other, the cooling fluid hole being formed on the anti-rotation surface. The cooling fin is formed in a position corresponding to the anti-rotation surface.

[0012] The anti-rotation surface may include an anti-rotation surface extending in the axial direction and positioned to face each other on the outer peripheral surface of the shaft body, and the heat sink may extend in the axial direction.

[0013] The length direction of the anti-rotation surface may be referred to as a first direction, and the width direction of the anti-rotation surface may be referred to as a second direction, the second direction being perpendicular to the first direction. The heat sink may include: an anti-rotation sheet having an end portion, the end portion being configured to face the anti-rotation surface and contact the anti-rotation surface; and a flow channel sheet spaced apart from the anti-rotation sheet in the second direction, and the flow channel sheet is spaced apart from the anti-rotation surface.

[0014] The cooling fluid hole may include: a first fluid hole; and a second fluid hole formed in a position spaced apart from the first fluid hole in the second direction. The anti-rotation sheet may be configured such that the end portion is located between the first fluid hole and the second fluid hole.

[0015] The runner plate may include: a plurality of first runner plates located on one side of the anti-rotation plate in the second direction and configured to form a first cooling channel connected to the first fluid hole; and a plurality of second runner plates located on an opposite side of the anti-rotation plate in the second direction and configured to form a second cooling channel connected to the second fluid hole.

[0016] Contact protrusions may be formed on the outer surface of the anti-rotation plate and the outer surface of the flow channel plate, and the contact protrusions may be in a spline shape.

[0017] The contact protrusion may extend in the first direction, and a cross section of the contact protrusion perpendicular to the anti-rotation surface may have a triangular sawtooth shape.

[0018] In the second direction, the thickness of the flow channel plate may be smaller than the thickness of the anti-rotation plate.

[0019] The rotor assembly may further include: a plurality of end plates configured to cover one side surface and opposite side surfaces of the rotor core in the axial direction, and the rotor shaft may pass through the end plates.

[0020] The end plate may include: a first end plate configured to cover the one side surface of the rotor core; and a second end plate configured to cover the opposite side surface of the rotor core.

[0021] A fluid discharge groove may be formed on the second end plate, wherein the fluid discharge groove is located between the rotor core and the second end plate and connected to the rotor cooling channel, so that the cooling fluid flowing through the rotor cooling channel is discharged to the outside of the rotor core.

[0022] According to another aspect of the present disclosure, the motor includes: a housing; a stator disposed in the housing; and a rotor assembly received inside the stator so as to be rotatable. The rotor assembly includes: a rotor core having a through hole formed to pass through a central portion of the rotor core in an axial direction of the rotor core; and a rotor shaft coupled to the rotor core through the through hole, and the rotor shaft has a hollow portion into which a cooling fluid is introduced. The rotor core includes a heat sink protruding from an inner peripheral surface of the rotor core to form a rotor cooling channel between the rotor core and the rotor shaft for the cooling fluid to flow. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings:

[0024] Figure 1 is a perspective view showing a rotor assembly according to an embodiment of the present disclosure;

[0025] Figure 2 is a perspective view showing a rotor shaft according to an embodiment of the present disclosure;

[0026] Figure 3 yes Figure 2 A front view of a rotor shaft according to an embodiment of the present disclosure shown in FIG.

[0027] Figure 4 is a perspective view showing a rotor core according to a first embodiment of the present disclosure;

[0028] Figure 5 Shows Figure 4 A front view and a partially enlarged view of a rotor core according to a first embodiment of the present disclosure shown in FIG.

[0029] Figure 6 yes Figure 5 A partial enlarged stereogram of part B in FIG.

[0030] Figure 7 is a front view showing a state in which a rotor core and a rotor shaft are coupled according to an embodiment of the present disclosure;

[0031] Figure 8 It is along Figure 1 A cross-sectional view taken along line AA;

[0032] Fig. 9 A front view and a partially enlarged view of a rotor core according to a second embodiment of the present disclosure are shown;

[0033] Fig.10 yes Fig. 9 A partial enlarged stereogram of part C in FIG.

[0034] Fig.11 A front view and a partially enlarged view showing a rotor core according to a third embodiment of the present disclosure; and

[0035] Fig.12 yes Fig.11 A partially enlarged stereoscopic image of part D in FIG. DETAILED DESCRIPTION

[0036] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0037] The following embodiments are embodiments suitable for understanding the technical features of the rotor assembly and the motor including the rotor assembly according to the present disclosure. However, the present disclosure is not limited to the application of the embodiments described below, and the technical features of the present disclosure are not limited by the described embodiments. In addition, various changes and modifications may be made without departing from the spirit and scope of the present disclosure.

[0038] Figure 1 is a perspective view showing a rotor assembly according to an embodiment of the present disclosure. Figure 2 is a perspective view showing a rotor shaft according to an embodiment of the present disclosure. Figure 3 yes Figure 2 A front view of a rotor shaft according to an embodiment of the present disclosure is shown in FIG. Figure 4is a perspective view showing a rotor core according to a first embodiment of the present disclosure. Figure 5 Shows Figure 4 2 is a front view and a partially enlarged view of a rotor core according to a first embodiment of the present disclosure shown in FIG. Figure 6 yes Figure 5 A partially enlarged stereoscopic image of part B in FIG. Figure 7 is a front view showing a state in which a rotor core and a rotor shaft are coupled according to an embodiment of the present disclosure. Figure 8 It is along Figure 1 A cross-sectional view taken along line AA.

[0039] Fig. 9 A front view and a partially enlarged view of a rotor core according to a second embodiment of the present disclosure are shown. Fig.10 yes Fig. 9 A partially enlarged stereoscopic image of part C in FIG. Fig.11 A front view and a partially enlarged view of a rotor core according to a third embodiment of the present disclosure are shown. Fig.12 yes Fig.11 A partially enlarged stereoscopic image of part D in FIG.

[0040] The motor according to the embodiment of the present disclosure may include a housing (not shown), a stator (not shown), and a rotor assembly 10 .

[0041] A space may be formed in the housing, and a plurality of components may be mounted in the space of the housing.

[0042] The stator may be disposed in the inner space of the housing, and the rotor assembly 10 may be received inside the stator so as to be rotatable.

[0043] For example, the stator may be fixedly mounted in the housing. The stator may include a wound coil, and when power is applied to the coil, the coil may be magnetized.

[0044] The rotor assembly 10 may be installed inside the stator so as to be rotatable. An induced current may be generated in the rotor assembly 10, and the rotor assembly 10 may be rotated relative to the stator by the induced current.

[0045] In the following, reference will be made to Figures 1 to 12 A rotor assembly 10 according to an embodiment of the present disclosure is described.

[0046] refer to Figures 1 to 12 , a rotor assembly 10 according to an embodiment of the present disclosure may include a rotor core 200 and a rotor shaft 100 .

[0047] The rotor core 200 may have a through hole 210 formed through a central portion of the rotor core in a length direction. When current is applied to the stator coil, an induced current may be generated, and the rotor core 200 may rotate.

[0048] The rotor shaft 100 may be coupled to the rotor core 200 through the through hole 210 , and may have a hollow portion into which a cooling fluid is introduced.

[0049] Specifically, the rotor shaft 100 may be integrally coupled with the rotor core 200 and may rotate together with the rotor core 200. The rotor shaft 100 may be formed in the form of a hollow shaft having a hollow portion formed therein, and the hollow portion 111 may be filled with a cooling fluid. For example, lubricating oil for a reduction bearing located in a housing may be supplied to the hollow portion 111 of the rotor shaft 100 as the cooling fluid. However, the type and inflow path of the cooling fluid supplied to the hollow portion 111 are not limited thereto.

[0050] More specifically, the rotor shaft 100 may include a shaft body 110 , an anti-rotation surface 120 , and a cooling fluid hole 130 .

[0051] A hollow portion 111 may be formed in the shaft body 110, and the hollow portion 111 may extend along the central axis of the shaft body 110. One side of the shaft body 110 in the length direction may be connected to a cooling fluid supply source, and the opposite side of the shaft body 110 in the length direction may be covered by an oil cover 113 to prevent leakage of the cooling fluid.

[0052] The anti-rotation surface 120 may be formed on at least a portion of the outer surface of the shaft body 110 in a planar shape.

[0053] For example, the anti-rotation surface 120 may be implemented as a flat surface by machining the shaft body 110 in a "D"-shaped cross section perpendicular to the central axis of the shaft body 110. The anti-rotation surface 120 may include a pair of anti-rotation surfaces 120 extending along the length direction of the shaft body 110, and the anti-rotation surfaces are positioned to face each other on the outer peripheral surface of the shaft body 110. However, the shape, position, and number of the anti-rotation surfaces 120 are not limited thereto.

[0054] The cooling fluid hole 130 may be formed through the shaft body 110 to connect the hollow portion 111 and the anti-rotation surface 120 , and the cooling fluid hole may be formed in a position corresponding to the anti-rotation surface 120 .

[0055] Specifically, the cooling fluid hole 130 may be formed through the shaft body 110 in a direction from the hollow portion 111 toward the anti-rotation surface 120, and the cooling fluid hole may form a channel through which the cooling fluid is released. The cooling fluid may be introduced into the hollow portion 111, and may be supplied between the shaft body 110 and the rotor core 200 through the cooling fluid hole 130. For example, as in the illustrated embodiment, the cooling fluid hole 130 may be formed in a position corresponding to an end portion in the length direction of the rotor core 200.

[0056] The cooling fins 230 may protrude from the inner circumferential surface of the rotor core 200 toward the rotor shaft 100 to form a rotor cooling passage P between the rotor core 200 and the rotor shaft 100 through which a cooling fluid flows.

[0057] The cooling fins 230 may be formed in a position corresponding to the anti-rotation surface 120. In addition, the cooling fins 230 may extend in the length direction of the anti-rotation surface 120. Therefore, a rotor cooling passage P extending in the length direction of the anti-rotation surface 120 may be formed between the cooling fins 230 and the anti-rotation surface 120. The cooling fluid released through the cooling fluid holes 130 may directly cool the rotor core 200 while flowing through the rotor cooling passage P.

[0058] Furthermore, the rotor core 200 can be prevented from rotating relative to the rotor shaft 100 by a structure in which the anti-rotation surface 120 is formed in a planar shape and the cooling fins 230 protrude toward the anti-rotation surface 120. That is, the rotor core 200 and the rotor shaft 100 can rotate together by this structure.

[0059] As described above, in the rotor assembly 10 and the motor including the same according to the embodiment of the present disclosure, the anti-rotation surface 120 may be formed on the rotor shaft 100, the cooling fins 230 may be formed on the inner surface of the rotor core 200, and the rotor cooling passage P through which the cooling fluid flows may be formed between the rotor shaft 100 and the rotor core 200, thereby directly cooling the rotor core 200 in an oil cooling method. In addition, the cooling performance of the motor may be improved.

[0060] In addition, according to an embodiment of the present disclosure, the heat sink 230 can prevent the rotor core 200 from rotating, and the sheet shape of the heat sink 230 can increase the flow area of ​​the rotor cooling channel P to increase the amount of heat transfer, thereby improving the cooling performance of the rotor core 200.

[0061] Hereinafter, for the convenience of description, the length direction of the anti-rotation surface 120 is referred to as a first direction D1, and the width direction of the anti-rotation surface 120 is referred to as a second direction D2, which is perpendicular to the first direction D1 (refer to Figure 2 ). The length direction of the anti-rotation surface 120 may be parallel to the axial direction of the shaft body 110 or the axial direction of the rotor core 200. The first direction and the second direction may be parallel to the anti-rotation surface 120.

[0062] The heat sink 230 may include an anti-rotation fin 240 and a flow passage fin 250 .

[0063] The anti-rotation sheet 240 may be disposed so that an end portion thereof facing the anti-rotation surface 120 is in contact with the anti-rotation surface 120 (refer to Figure 7). The flow channel plate 250 may be spaced apart from the anti-rotation plate 240 in the second direction, and the flow channel plate may be spaced apart from the anti-rotation surface 120 (refer to Figures 4 to 12 ).

[0064] Specifically, the anti-rotation sheet 240 is a member that contacts the anti-rotation surface 120 to prevent the rotor core 200 from rotating. For example, the anti-rotation sheet 240 may be located at the center of the plurality of heat dissipation sheets 230 in the second direction. In addition, the end surface of the anti-rotation sheet 240 facing the anti-rotation surface 120 may be formed flat so as to correspond to the anti-rotation surface 120, and the anti-rotation sheet is connected face-to-face with the anti-rotation surface 120 to effectively prevent the rotation of the rotor core 200. However, the end surface of the anti-rotation sheet 240 is not limited thereto.

[0065] The flow channel sheet 250 for forming the rotor cooling passage P together with the anti-rotation sheet 240 may increase the surface area of ​​the rotor core 200 for cooling.

[0066] For example, the cooling fluid hole 130 may include a first fluid hole 131 and a second fluid hole 132 formed in a position spaced apart from the first fluid hole 131 in the second direction. The anti-rotation sheet 240 may be provided so that the end portion in contact with the anti-rotation surface 120 is located between the first fluid hole 131 and the second fluid hole 132. However, the number of the cooling fluid holes 130 and the positional relationship between the cooling fluid holes 130 and the anti-rotation sheet 240 are not limited thereto, and may be modified in various ways as long as the rotor cooling channel P can be formed.

[0067] For example, the flow channel plate 250 may include a first flow channel plate 251 and a second flow channel plate 252 , which are different from the anti-rotation plate 240 .

[0068] The first flow channel plate 251 may be located on one side of the anti-rotation plate 240 in the second direction and may form a first cooling channel P1 connected to the first fluid hole 131. The second flow channel plate 252 may be located on an opposite side of the anti-rotation plate 240 in the second direction and may form a second cooling channel P2 connected to the second fluid hole 132.

[0069] The number and size of the first runner piece 251 and the second runner piece 252 are not limited to the illustrated embodiment. The first runner piece 251 and the second runner piece 252 may have a size different from the anti-rotation piece 240, and the number of the first runner piece 251 and the second runner piece 252 may be variously changed according to the installation environment. Like the anti-rotation piece 240, the first runner piece 251 and the second runner piece 252 may extend in the first direction.

[0070] Specifically, the plurality of first runner pieces 251 may be spaced apart from each other in the second direction. In order to form the first cooling channel P1 through which the cooling fluid flows, the first runner piece 251 may be spaced apart from the anti-rotation sheet 240, and the first runner pieces may be spaced apart from each other. The cooling fluid introduced into the hollow portion 111 may move to the first cooling channel P1 through the first fluid hole 131. Because the first runner piece 251 is spaced apart from the anti-rotation surface 120, the cooling fluid released through the first fluid hole 131 may be supplied between the first runner piece 251 and the anti-rotation sheet 240, and between the plurality of first runner pieces 251.

[0071] A plurality of second runner plates 252 may be spaced apart from each other in the second direction. In order to form a second cooling channel P2 through which the cooling fluid flows, the second runner plates 252 may be spaced apart from the anti-rotation plate 240, and the second runner plates may be spaced apart from each other. The cooling fluid introduced into the hollow portion 111 may move to the second cooling channel P2 through the second fluid hole 132. Because the second runner plates 252 are spaced apart from the anti-rotation surface 120, the cooling fluid released through the second fluid hole 132 may be supplied between the second runner plates 252 and the anti-rotation plate 240, and may be supplied between the plurality of second runner plates 252. The rotor cooling channel P may be implemented by the first cooling channel P1 and the second cooling channel P2.

[0072] The first cooling passage P1 and the second cooling passage P2 may extend from one end portion of the rotor core 200 to the opposite end portion of the rotor core. The cooling fluid released to the outside of the rotor shaft 100 through the cooling fluid hole 130 may move in the first cooling passage P1 and the second cooling passage P2 while directly cooling the rotor core 200. Since a plurality of first flow channel fins 251 and a plurality of second flow channel fins 252 are provided, the contact area between the heat sink 230 and the cooling fluid may be increased, and thus the cooling efficiency may be improved.

[0073] Meanwhile, the anti-rotation sheet 240 and the flow channel sheet 250 may be modified in various forms to increase their contact area with the cooling fluid flowing through the rotor cooling channel P. For example, Figures 4 to 7 The rotor core 200 according to the first embodiment of the present disclosure is shown. Figures 9 and 10 The rotor core 200 according to the second embodiment of the present disclosure is shown. Figure 11 to Figure 12 The rotor core 200 according to the third embodiment of the present disclosure is shown. However, the shape of the rotor core 200 is not limited to the shown embodiment and may be modified in various ways.

[0074] refer to Figures 4 to 7In the case of the rotor core 200 according to the first embodiment of the present disclosure, the runner plate 250 may have the same thickness in the second direction as the anti-rotation plate 240. However, the thickness of the runner plate 250 and the anti-rotation plate 240 may not be limited to the above-described embodiment.

[0075] refer to Figures 9 and 10 In the case of the rotor core 200 according to the second embodiment of the present disclosure, contact protrusions S having a spline shape may be formed on the outer surfaces of the anti-rotation sheet 240 and the flow channel sheet 250 .

[0076] Specifically, the contact protrusions S may be formed on the outer surfaces of the runner plate 250 and the anti-rotation plate 240 that are in contact with the cooling fluid. The contact protrusions S may extend in a first direction. Some of the contact protrusions S may protrude in the direction in which the runner plate 250 and the anti-rotation plate 240 face each other or in the direction in which adjacent runner plates 250 face each other. In addition, the remaining contact protrusions S (e.g., the contact protrusions S protruding from the surface of the runner plate 250 facing the anti-rotation plate 240) may protrude toward the anti-rotation surface 120. The contact protrusions S may be implemented in a spline shape on the outer surfaces of the runner plate 250 and the anti-rotation plate 240 through this structure.

[0077] For example, the contact protrusion S may extend in the first direction, and a cross section of the contact protrusion S perpendicular to the anti-rotation surface 120 may have a triangular sawtooth shape. In addition, the contact protrusion S may increase the surface area of ​​the flow channel sheet 250 and the anti-rotation sheet 240 without hindering the flow of the cooling fluid. The contact protrusion S may not be formed on the end surface of the anti-rotation sheet 240 facing the anti-rotation surface 120. However, the contact protrusion S may be formed on the anti-rotation surface 120 to prevent relative movement of the rotor core 200.

[0078] The rotor core 200 according to the second embodiment of the present disclosure includes a contact protrusion S located on the heat sink 230, thereby increasing the contact area with the cooling fluid compared to the rotor core 200 according to the first embodiment of the present disclosure. In addition, the rotor core 200 according to the second embodiment of the present disclosure can increase heat transfer, thereby improving cooling efficiency.

[0079] refer to Fig.11 and Fig.12 In the case of the rotor core 200 according to the third embodiment of the present disclosure, the thickness of the flow channel plate 250 may be smaller than the thickness of the anti-rotation plate 240 in the second direction.

[0080] Specifically, the anti-rotation sheet 240 may have a thickness in the second direction sufficient to contact the anti-rotation surface 120 and perform rotation prevention. The runner sheet 250 may have a small thickness in the second direction in order to increase the surface area of ​​the rotor cooling channel P to a maximum. For example, the first runner sheet 251 and the second runner sheet 252 may be formed in a thin plate shape.

[0081] Therefore, the rotor core 200 according to the third embodiment of the present disclosure may increase heat transfer to the cooling fluid, thereby improving cooling efficiency.

[0082] Meanwhile, the present disclosure may further include an end plate 300. The end plate 300 may cover one side surface and opposite side surfaces of the rotor core 200 in the length direction, and the rotor shaft 100 may pass through the end plate 300.

[0083] Specifically, the end plate 300 may include a first end plate 310 covering one side surface of the rotor core 200 , and a second end plate 320 covering an opposite side surface of the rotor core 200 .

[0084] The first end plate 310 may be disposed on one side of the rotor core 200, that is, on the side where the cooling fluid is introduced. The second end plate 320 may be disposed on the opposite side of the rotor core 200, that is, on the side where the cooling fluid is released. For example, the rotor cooling passage P may extend between the first end plate 310 and the second end plate 320.

[0085] The second end plate 320 may include a fluid discharge groove 321. The fluid discharge groove 321 may be provided between the rotor core 200 and the second end plate 320, and the fluid discharge groove may be connected to the rotor cooling channel P so that the cooling fluid flowing through the rotor cooling channel P is discharged to the outside of the rotor core 200.

[0086] For example, the cooling fluid hole 130 may be formed adjacent to the first end plate 310. The fluid discharge groove 321 may be formed on a surface in contact with an opposite side surface of the rotor core 200. The cooling fluid may be dispersed from the rotor cooling channel P to the outside of the rotor core 200 through the fluid discharge groove 321. For example, the cooling fluid discharged from the fluid discharge groove 321 may be dispersed to the inside of the end coil (not shown) and may additionally cool the end coil.

[0087] In the following, reference will be made to Figure 8 Describe the path that the cooling fluid travels.

[0088] The cooling fluid may be introduced into the hollow portion 111 of the rotor core 100. The cooling fluid introduced into the hollow portion 111 may be introduced into a rotor cooling passage P formed between the rotor core 200 and the rotor shaft 100 through the cooling fluid hole 130. The cooling fluid introduced into the rotor cooling passage P may move along the rotor cooling passage P in a first direction and may directly cool the rotor core 200.

[0089] The cooling fluid moving along the rotor cooling passage P may be dispersed to the outside through the fluid discharge holes 321 formed on the second end plate 320 .

[0090] As described above, in the rotor assembly and the motor including the rotor assembly according to the embodiment of the present disclosure, an anti-rotation surface may be formed on the rotor shaft, a heat sink may be formed on the inner surface of the rotor core, and a rotor cooling channel for a cooling fluid to flow through may be formed between the rotor shaft and the rotor core to directly cool the rotor core using an oil cooling method. Thus, the cooling performance of the motor may be improved.

[0091] In addition, according to the embodiments of the present disclosure, the cooling fins can prevent the rotor core from rotating, and the fin shape of the cooling fins can increase the flow area of ​​the rotor cooling channel to increase the amount of heat transfer, thereby improving the cooling performance of the rotor core.

[0092] The rotor assembly and the motor including the rotor assembly according to the embodiment of the present disclosure can directly cool the rotor core by an oil cooling method by forming a rotor cooling channel for a cooling fluid to flow between the rotor core and the rotor shaft and by forming an anti-rotation surface on the rotor shaft and a cooling fin on the inner surface of the rotor core. Therefore, the cooling performance of the motor can be improved.

[0093] In addition, according to an embodiment of the present disclosure, a rotor assembly and an electric motor including the rotor assembly can use a heat sink to prevent the rotor core from rotating, and can increase the flow area of ​​the rotor cooling channel by using the shape of the heat sink to increase the amount of heat transfer, thereby improving the cooling performance of the rotor core.

[0094] This application claims priority to and the benefit of Korean Patent Application No. 10-2021-0031099 filed in the Korean Intellectual Property Office on March 10, 2021, the entire contents of which are incorporated herein by reference.

[0095] Although the present disclosure has been described above with reference to the exemplary embodiments and the accompanying drawings, the present disclosure is not limited thereto but various modifications and changes may be made by those skilled in the art without departing from the spirit and scope of the present disclosure as claimed in the appended claims.

Claims

1. A rotor assembly, comprising: a rotor core having a through hole formed to pass through a central portion of the rotor core in an axial direction of the rotor core; as well as a rotor shaft coupled to the rotor core through the through hole, and having a hollow portion into which a cooling fluid is introduced, wherein a cooling fin protrudes from the inner peripheral surface of the rotor core toward the rotor shaft to form a rotor cooling channel between the rotor core and the rotor shaft for a cooling fluid to flow through; Wherein, the rotor shaft comprises: A shaft body, in which the hollow portion is formed; an anti-rotation surface formed in a planar shape on at least a portion of an outer surface of the shaft body; and a cooling fluid hole that passes through the shaft body and connects the hollow portion and the anti-rotation surface to each other, the cooling fluid hole being formed on the anti-rotation surface, and Wherein, the heat sink is formed in a position corresponding to the anti-rotation surface.

2. The rotor assembly according to claim 1, wherein: The anti-rotation surface includes a counter-rotation surface extending in the axial direction and positioned to face each other on the outer peripheral surface of the shaft body, and Wherein, the heat sink extends along the axial direction.

3. The rotor assembly according to claim 1, wherein: The length direction of the anti-rotation surface is referred to as a first direction, and the width direction of the anti-rotation surface is referred to as a second direction, the second direction being perpendicular to the first direction, and Wherein, the heat sink comprises: an anti-rotation sheet having an end portion configured to face the anti-rotation surface and to be in contact with the anti-rotation surface; and A flow channel plate is spaced apart from the anti-rotation plate in the second direction, and the flow channel plate is spaced apart from the anti-rotation surface.

4. The rotor assembly according to claim 3, wherein: The cooling fluid hole comprises: a first fluid aperture; and a second fluid hole formed in a position spaced apart from the first fluid hole along the second direction, and The anti-rotation sheet is configured such that the end portion is located between the first fluid hole and the second fluid hole.

5. The rotor assembly according to claim 4, wherein: The runner plate comprises: a plurality of first flow channel plates located on one side of the anti-rotation plate in the second direction and configured to form a first cooling channel connected to the first fluid hole; and A plurality of second flow channel plates are located on opposite sides of the anti-rotation plate in the second direction and are configured to form second cooling channels connected to the second fluid holes.

6. The rotor assembly according to claim 3, wherein: Contact protrusions are formed on the outer surface of the anti-rotation plate and the outer surface of the flow channel plate, and the contact protrusions are in a spline shape.

7. The rotor assembly according to claim 6, wherein: The contact protrusion extends in the first direction, and a cross section of the contact protrusion perpendicular to the anti-rotation surface has a triangular sawtooth shape.

8. The rotor assembly according to claim 3, wherein: In the second direction, the thickness of the flow channel plate is smaller than the thickness of the anti-rotation plate.

9. The rotor assembly of claim 1, further comprising: A plurality of end plates are configured to cover one side surface and opposite side surfaces of the rotor core in the axial direction, wherein the rotor shaft passes through the end plates.

10. The rotor assembly according to claim 9, wherein: The end plate comprises: a first end plate configured to cover the one side surface of the rotor core; and The second end plate is configured to cover the opposite side surfaces of the rotor core.

11. The rotor assembly according to claim 10, wherein: A fluid discharge groove is formed on the second end plate. The fluid discharge groove is located between the rotor core and the second end plate and connected to the rotor cooling channel, so that the cooling fluid flowing through the rotor cooling channel is discharged to the outside of the rotor core.

12. A motor, comprising: case; a stator, disposed in the housing; as well as a rotor assembly received within the stator so as to be rotatable, Wherein, the rotor assembly comprises: a rotor core having a through hole formed to pass through a central portion of the rotor core in an axial direction of the rotor core; and a rotor shaft coupled to the rotor core through the through hole, and the rotor shaft has a hollow portion into which a cooling fluid is introduced, and wherein the rotor core comprises cooling fins, the cooling fins protruding from the inner peripheral surface of the rotor core to form a rotor cooling channel between the rotor core and the rotor shaft for cooling fluid to flow through; Wherein, the rotor shaft comprises: A shaft body, in which the hollow portion is formed; an anti-rotation surface formed in a planar shape on at least a portion of an outer surface of the shaft body; and a cooling fluid hole that passes through the shaft body and connects the hollow portion and the anti-rotation surface to each other, the cooling fluid hole being formed on the anti-rotation surface, and Wherein, the heat sink is formed in a position corresponding to the anti-rotation surface.

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