Rotor assembly and motor including it

Abstract

According to one aspect of this disclosure, a rotor assembly includes a rotor core having a through hole disposed at its central portion along the axial direction of the rotor core; and a rotor shaft passing through the through hole and coupled to the rotor core; the rotor shaft includes a shaft body having a hollow portion therein; cooling fluid orifices including a plurality of cooling holes passing through the shaft body to discharge cooling fluid introduced through the hollow portion to the outside of the shaft body, and arranged spaced apart from each other along the axial direction of the shaft body; and a support flange projecting radially on the outer surface of the shaft body to restrict axial movement of the rotor core and having a channel communication hole.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2021-0064733, filed with the Korean Intellectual Property Office on May 20, 2021, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to a rotor assembly and an electric motor including the same, and more particularly to a rotor assembly for improving the cooling efficiency of an oil-cooled electric motor and an electric motor including the same. Background Technology

[0004] Drive motors are configured to generate rotational force when powered and have various structures. For example, a drive motor for an electric vehicle may include a housing, a stator mounted inside the housing, and a rotor integrally connected to a rotating shaft inside the stator. When current is applied to the stator coils mounted in the stator, an induced current is generated in the rotor, which generates rotational force as the rotor rotates.

[0005] The heat sources of a drive motor are the stator coils through which current flows and the rotor core through which magnetic flux flows. When the drive motor is running, the temperature of the corresponding components will rise, and if the temperature rises too much, its function may malfunction. Therefore, it is important to effectively cool the heat generated by the motor.

[0006] Solutions for cooling the heat generated by an electric motor include oil cooling solutions that directly supply oil to the heat source, and water cooling solutions that indirectly cool the heat source by allowing cooling water to flow in the housing channels.

[0007] Traditional oil cooling systems involve installing pipes to supply oil into the housing and then spraying oil from these pipes to directly cool the stator core and stator coils. However, with conventional oil cooling systems, the axial ends of the stator core mounted near the pipes and stator coils are easily cooled, but this can lead to reduced cooling efficiency in areas that are difficult to cool directly with oil. For example, the middle region of the stator core or a portion of the rotor core may be covered by end plates or coils, making it difficult to cool directly with oil sprayed from the pipes.

[0008] Therefore, it is necessary to improve the technology to effectively cool components that are difficult to cool directly using current oil cooling solutions. Summary of the Invention

[0009] This disclosure aims to solve the aforementioned problems in the prior art while maintaining the advantages of the prior art.

[0010] One aspect of this disclosure provides a rotor assembly that, by improving the structure of the rotor core, rotor shaft, and motor including the rotor core and rotor shaft, can directly cool components in existing oil-cooling systems that are difficult for cooling fluids to cool directly, without the need to add separate components.

[0011] Another aspect of this disclosure provides a rotor assembly and an electric motor including the rotor assembly, which can improve cooling efficiency, improve motor efficiency, thereby reducing magnet specifications and thus reducing manufacturing costs.

[0012] The technical problems to be solved by the present invention are not limited to those described above. Those skilled in the art to which this disclosure pertains will clearly understand any other technical problems not mentioned herein through the following description.

[0013] According to one aspect of this disclosure, a rotor assembly includes a rotor core having a through-hole disposed at its central portion along the axial direction of the rotor core; and a rotor shaft passing through the through-hole and coupled to the rotor core. The rotor shaft includes a shaft body having a hollow portion therein; cooling fluid orifices including a plurality of cooling holes passing through the shaft body to discharge cooling fluid introduced through the hollow portion to the outside of the shaft body, and spaced apart from each other along the axial direction of the shaft body; and a support flange projecting radially onto the outer surface of the shaft body to restrict axial movement of the rotor core and having a channel communication hole. The rotor core includes rotor cooling channels extending in the axial direction of the rotor core, communicating with some of the plurality of cooling holes, passing through the channel communication hole, and configured such that the cooling fluid flows through it.

[0014] The rotor core may include multiple sub-cores, which are stacked along the axial direction of the rotor core and form the rotor cooling channel in the stacked state of the multiple sub-cores, and the support flange can be inserted between adjacent sub-cores.

[0015] The cooling fluid orifice may include a first cooling hole, disposed at a position corresponding to one axial end of the rotor core and communicating with the rotor cooling channel; and a second cooling hole, disposed on the opposite side of the first cooling hole, spaced apart from the first cooling hole and disposed at a position corresponding to the support flange.

[0016] The first cooling holes may be spaced apart from each other along the circumference of the shaft, and the second cooling holes may be spaced apart from each other along the circumference of the shaft.

[0017] The support flange may include a support body having the channel communication hole; and a channel portion having a cutout shape at a portion of the support body and extending radially from the shaft to communicate with the second cooling hole, and the rotor core may also include a stator cooling channel extending radially between adjacent sub-cores of the plurality of sub-cores, disposed in a region corresponding to the channel portion, and configured such that the cooling fluid discharged through the second cooling hole flows radially.

[0018] The rotor assembly may further include a first end plate covering one axial end of the rotor core and a second end plate covering one opposite axial end of the rotor core.

[0019] The first end plate may include an intake hole communicating with a first cooling hole; and a first channel groove, which is concave on the surface facing the rotor core, is arranged along the circumferential direction of the rotor shaft, is connected to the intake hole, and communicates with the rotor cooling channel through the intake hole.

[0020] The second end plate includes a first surface facing the rotor core and a second surface corresponding to the first surface. The second end plate may include a second channel groove that is concave on the first surface of the second end plate, is disposed along the circumferential direction of the rotor shaft and communicates with the rotor cooling channel; and a discharge hole that penetrates the second end plate and extends between the second channel groove and the second surface to discharge the cooling fluid introduced into the second channel groove.

[0021] As the discharge port extends from the second channel groove in a direction toward the second surface, the discharge port can be tilted away from the rotor shaft.

[0022] The cooling fluid orifice may include a third cooling orifice disposed on one side of the first cooling orifice and spaced apart from the first cooling orifice; and a fourth cooling orifice disposed between the first cooling orifice and the third cooling orifice.

[0023] The third cooling holes are spaced apart from each other along the circumference of the shaft, and the fourth cooling holes are spaced apart from each other along the circumference of the shaft.

[0024] According to another aspect of this disclosure, the motor includes a housing, a stator disposed within the housing, and a rotor assembly rotatable within the stator. The rotor assembly includes a rotor core having a through-hole disposed at its central portion along the axial direction of the rotor core; and a rotor shaft passing through the through-hole and coupled to the rotor core. The rotor shaft includes a shaft body having a hollow portion therein; cooling fluid orifices including a plurality of cooling holes passing through the shaft body to discharge cooling fluid introduced through the hollow portion to the outside of the shaft body, and spaced apart from each other along the axial direction of the shaft body; and a support flange projecting radially onto the outer surface of the shaft body to restrict axial movement of the rotor core and having a channel communication hole. The rotor core includes rotor cooling channels extending axially in the rotor core, communicating with some of the plurality of cooling holes, passing through the channel communication hole, and configured such that the cooling fluid flows through it.

[0025] The support flange may include a support body having the channel communication hole; and a channel portion having a cutout shape at a portion of the support body and extending radially from the shaft to communicate with some of the plurality of cooling holes. The rotor core may also include a plurality of sub-cores stacked axially along the rotor core and forming the rotor cooling channel in the stacked state of the plurality of sub-cores; and a stator cooling channel extending radially between adjacent sub-cores, disposed in a region corresponding to the channel portion, and configured such that the cooling fluid discharged through some of the cooling holes flows radially.

[0026] The motor may further include a coil section disposed inside the stator, some of the plurality of cooling holes may be disposed at positions corresponding to the coil section, and the cooling fluid flowing through the rotor cooling channel may be discharged toward the opposite end of the coil section.

[0027] The motor may also include a bearing component mounted on one end of the rotor shaft, and some of the plurality of cooling holes may be located at positions corresponding to the bearing component. Attached Figure Description

[0028] The above and other objects, features and advantages of this disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings:

[0029] Figure 1 A perspective view of an electric motor including a rotor assembly according to an embodiment of the present disclosure;

[0030] Figure 2 To illustrate an electric motor including a rotor assembly according to an embodiment of the present disclosure, and for Figure 1 A sectional view;

[0031] Figure 3 A perspective view of a rotor assembly according to an embodiment of the present disclosure is shown;

[0032] Figure 4 To show from Figure 3 A perspective view of the rotor assembly with the first end plate and some core components removed.

[0033] Figure 5 A perspective view of a rotor shaft according to an embodiment of the present disclosure is shown;

[0034] Figure 6 To illustrate a view of a support flange according to an embodiment of the present disclosure, and for Figure 5 A magnified perspective view of a portion;

[0035] Figure 7 A cross-sectional view of a rotor shaft according to an embodiment of the present disclosure;

[0036] Figure 8 To illustrate a view of a rotor core according to an embodiment of the present disclosure, and for Figure 3 A partial enlarged cross-sectional perspective view;

[0037] Figure 9 This is a view of a second end plate according to an embodiment of the present disclosure, and a perspective view viewed from a first side;

[0038] Figure 10 This is a view of a second end plate according to an embodiment of the present disclosure, and a perspective view viewed from a second side;

[0039] Figure 11 A cross-sectional view of a second end plate according to an embodiment of the present disclosure; and

[0040] Figure 12 for Figure 2 An enlarged sectional view of part A. Detailed Implementation

[0041] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings.

[0042] First, the embodiments described herein are suitable for understanding the technical features of the rotor assembly and the motor including the rotor assembly according to this disclosure. However, this disclosure is not limited to the embodiments described below, nor are the technical features of this disclosure limited to the described embodiments, and various modifications can be made to this disclosure without departing from its technical scope.

[0043] Figure 1 A perspective view of an electric motor including a rotor assembly according to an embodiment of the present disclosure is shown. Figure 2To illustrate an electric motor including a rotor assembly according to an embodiment of the present disclosure, and for Figure 1 sectional view of . Figure 3 A perspective view of a rotor assembly according to an embodiment of the present disclosure is shown. Figure 4 To show from Figure 3 A perspective view of the rotor assembly with the first end plate and some core components removed. Figure 5 A perspective view of a rotor shaft according to an embodiment of the present disclosure is shown. Figure 6 To illustrate a view of a support flange according to an embodiment of the present disclosure, and for Figure 5 A magnified perspective view of a portion of the image. Figure 7 This is a cross-sectional view of a rotor shaft according to an embodiment of the present disclosure. Figure 8 To illustrate a view of a rotor core according to an embodiment of the present disclosure, and for Figure 3 A partial magnified cross-sectional perspective view. Figure 9 This is a view of a second end plate according to an embodiment of the present disclosure, and is a perspective view viewed from the first side. Figure 10 This is a view of a second end plate according to an embodiment of the present disclosure, and a perspective view viewed from the second side. Figure 11 This is a cross-sectional view of a second end plate according to an embodiment of the present disclosure. Figure 12 for Figure 2 An enlarged sectional view of part A.

[0044] Reference Figure 1-12 According to an embodiment of the present disclosure, an electric motor 1 including a rotor assembly 10 includes a housing 20, a stator 30, and a rotor assembly 10. Furthermore, the electric motor 1 may also include a coil portion 50 and a bearing member 40.

[0045] The interior of the housing 20 has space, and multiple components can be installed in this space.

[0046] The stator 30 is disposed inside the housing 20. For example, the stator 30 can be installed in a state where it is fixed inside the housing 20.

[0047] The coil portion 50 may be disposed inside the stator 30. For example, the coil portion 50 may be wound around the stator and may be magnetized when a power source is applied to it. In the following text, for ease of description, one end of the coil portion 50 relative to the axial direction of the stator 30 will be referred to as the side coil end 51, and the opposite end of the coil portion 50 will be referred to as the opposite side coil end 52.

[0048] The rotor assembly 10 can be installed inside the stator 30 and is rotatable. More specifically, an induced current can be generated in the rotor assembly 10, so that the rotor assembly 10 can rotate relative to the stator 30.

[0049] The bearing 40 can be installed at one end of the rotor shaft 100 disposed in the rotor assembly 10. Specifically, the bearing 40 is installed between the rotor shaft 100 and the housing (or housing cover) 20 and can support the rotation of the rotor shaft 100.

[0050] The rotor assembly 10 includes a rotor core 200, wherein a through hole 210 is formed in its central portion along its axial direction; and a rotor shaft 100, which passes through the through hole 210 to be coupled to the rotor core 200.

[0051] The rotor shaft 100 includes a shaft body 110 having a hollow portion 111 therein; a cooling fluid orifice including a plurality of cooling holes 113, 114, 115 and 116 passing through the shaft body 110 to discharge cooling fluid introduced through the hollow portion 111 to the outside of the shaft body 110 and spaced apart from each other along the axial direction of the shaft body 110; and a support flange 130 that protrudes radially on the outer surface of the shaft body 110 to restrict axial movement of the rotor core 200 and has a channel communication hole 132.

[0052] Here, the rotor core 200 includes a rotor cooling channel 220 which extends in the axial direction of the rotor core 200 and inside the rotor core 200, communicates with some of the cooling holes among a plurality of cooling holes, passes through a channel communication hole 132, and is configured to allow cooling fluid to flow through it.

[0053] Furthermore, some of the multiple cooling holes can be formed at positions corresponding to one side coil end 51, which is one end of the coil section 50. Additionally, the cooling fluid flowing through the rotor cooling channel 220 can be discharged toward the opposite side coil end 52, which is the opposite end of the coil section 50.

[0054] In the following text, reference will be made to Figure 1-12 A rotor assembly 10 according to an embodiment of the present disclosure is described.

[0055] Reference Figure 1-12 According to an embodiment of the present disclosure, the rotor assembly 10 includes a rotor core 200 and a rotor shaft 100.

[0056] A through-hole 210 is formed in the axial direction of the rotor core 200 at the center portion of the rotor core 200. When current is applied to the coils of the stator 30, the rotor core 200 rotates due to the induced current. The rotor core 200 rotates due to the induced current generated when current is applied to the coil section 50.

[0057] The rotor shaft 100 may have a hollow portion 111 through which it passes through a through hole 210 to be coupled to the rotor core 200, and cooling fluid flows through the hollow portion 111 therein. The rotor shaft 100 may be coupled to the rotor core 200 to rotate together with the rotor core 200.

[0058] More specifically, the rotor shaft 100 may include a shaft body 110, a cooling fluid orifice, and a support flange 130.

[0059] The shaft 110 may have a hollow portion 111 inside, and the hollow portion 111 may be formed as long along the central axis of the shaft 110. An oil inlet 112 for introducing cooling fluid is formed at one axial end of the shaft 110, and the oil inlet 112 may be connected to a cooling fluid supply source (not shown).

[0060] The cooling fluid orifice can pass through the shaft 110 to discharge the cooling fluid introduced into the hollow portion 111 to the outside of the shaft 110. In addition, the cooling fluid orifice includes a plurality of cooling holes arranged spaced apart from each other along the axial direction of the shaft 110.

[0061] The support flange 130 protrudes radially on the outer surface of the shaft 110 to restrict the axial movement of the rotor core 200, and has a channel communication hole 132.

[0062] Specifically, the support flange 130 protrudes from the outer surface of the shaft 110, supports the rotor core 200, and prevents axial movement of the rotor core 200. Furthermore, the support flange 130 according to this disclosure has a channel in partial communication with cooling fluid to cool the rotor core 200 or the stator 30.

[0063] The rotor core 200 also includes a rotor cooling channel 220. The rotor cooling channel 220 extends axially inside the rotor core 200, communicates with some of the cooling holes among a plurality of cooling holes, passes through a channel communication hole 132, and is configured to allow cooling fluid to flow through it.

[0064] Rotor cooling channels 220 can extend from one axial end of rotor core 200 toward its opposite axial end. Furthermore, multiple rotor cooling channels 220 can be arranged along the circumferential direction of rotor shaft 100. As an example, rotor core 200 may include eight rotor cooling channels 220 arranged spaced apart from each other, but the number of rotor cooling channels 220 is not limited to this.

[0065] Here, the rotor core 200 may include a plurality of sub-cores 200a, which are stacked along the axial direction of the rotor core 200 and form a rotor cooling channel 220 in the stacked state of the plurality of sub-cores 200a. More specifically, the rotor core 200 may have a structure in which the plurality of sub-cores 200a can be stacked sequentially along the axial direction of the rotor shaft 100. As an example, four sub-cores 200a may be provided as shown in the example, but this disclosure is not limited thereto. With the plurality of sub-cores 200a assembled in the shaft 110, the rotor cooling channel 220 may extend along the axial direction of the shaft 110.

[0066] The support flange 130 can be inserted between adjacent sub-cores 200a of a plurality of sub-cores 200a.

[0067] For example, the support flange 130 can be positioned at a location corresponding to the center portion of the rotor core 200 in the axial direction. Taking the arrangement of four sub-cores 200a as shown in the embodiment as an example, the support flange 130 can be positioned between two sub-cores 200a. That is, the two sub-cores 200a can be arranged on opposite axial sides, with the support flange 130 inserted between them.

[0068] The channel communication hole 132 provided in the support flange 130 can be arranged along the circumferential direction of the rotor shaft 100. Furthermore, the channel communication hole 132 can be provided at a position corresponding to the location where the rotor cooling channel 220 is formed (see...). Figure 2 , 4 (and 8). For example, when eight rotor cooling channels 220 are provided inside the rotor core 200, eight channel connecting holes 132 can be provided at the corresponding positions of the rotor cooling channels 220 of the support flange 130. Even when the support flange 130 is inserted between two sub-cores 200a, the rotor cooling channels 200 can still be connected through the channel connecting holes 132.

[0069] The cooling fluid orifice may include a first cooling orifice 113 and a second cooling orifice 114. Furthermore, the cooling fluid orifice may include a third cooling orifice 115 and a fourth cooling orifice 116.

[0070] The first cooling hole 113 may be formed at a position corresponding to one axial end of the rotor core 200 and may communicate with the rotor cooling channel 220. The first cooling hole 113 may be configured to supply cooling fluid in the hollow portion 111 of the rotor shaft 100 to the rotor cooling channel 220.

[0071] The second cooling hole 114 is formed on the opposite side of the first cooling hole 113 to be spaced apart from the first cooling hole 113, and may be formed at a position corresponding to the support flange 130. The second cooling hole 114 may be configured to supply cooling fluid in the hollow portion 111 of the rotor shaft 100 to the space between the plurality of split cores 200a to cool the stator 30.

[0072] Here, the plurality of first cooling holes 113 and the plurality of second cooling holes 114 may be spaced apart from each other along the circumferential direction of the shaft 110. Here, four first cooling holes 113 and four second cooling holes 114 may be arranged along the circumferential direction of the shaft 110, but this disclosure is not limited thereto. Furthermore, the dimensions of the first cooling holes 113 and the diameters of the second cooling holes 114 may be the same or different. For example, as... Figure 4 As shown, the diameter of the first cooling hole 113 can be larger than the diameter of the second cooling hole 114.

[0073] Specifically, the support flange 130 may include a support body 131 and a channel portion 135.

[0074] The support body 131 forms the main body of the support flange 130 and can protrude radially from the shaft 110 and be inserted between a plurality of sub-cores 200a to restrict axial movement of the rotor core 200. The support body 131 may have a plurality of channel communication holes 132.

[0075] The channel portion 135 may be formed at a portion of the support 131 to be cut, extends radially from the shaft 110, and communicates with the second cooling hole 114.

[0076] The rotor core 200 may include stator cooling channels 230. The stator cooling channels 230 may be disposed between adjacent core sections 200a and may extend radially in the rotor shaft 100. Moreover, the stator cooling channels 230 may be formed in a region corresponding to the channel portion 135 and may be configured such that cooling fluid discharged through the second cooling hole 114 flows radially.

[0077] Specifically, the channel portion 135 can be formed at a position corresponding to the second cooling hole 114, and can form a flow channel along which the cooling fluid discharged through the second cooling hole 114 flows. Furthermore, the flow channel can form part of the stator cooling channel 230. The stator cooling channel 230 is a channel formed inside the rotor core 200 through the support flange 130, and is a channel for supplying cooling fluid to the interior of the stator 30.

[0078] The stator cooling channel 230 may be provided in a portion between adjacent core bodies 200a, with the support flange 130 inserted in this portion, and the stator cooling channel 230 may extend radially in the shaft body 110. That is, the stator cooling channel 230 may be a channel that passes through the space formed by the channel portion 135 from the second cooling hole 114 and extends into the interior of the stator 30.

[0079] In embodiments of this disclosure, cooling fluid supplied to the hollow portion 111 of the rotor shaft 100 can be supplied to the middle portion inside the stator 30 by providing stator cooling channels 230, thus effectively cooling the stator 30. Furthermore, since the stator cooling channels 230 are formed inside the rotor core 200, they can additionally cool the rotor core 200 during the radial flow of the cooling fluid.

[0080] The cooling fluid orifice may include a third cooling orifice 115 and a fourth cooling orifice 116. The third cooling orifice 115 may be formed on one side of the first cooling orifice 113 and arranged spaced apart from each other, and the fourth cooling orifice 116 may be formed between the first cooling orifice 113 and the third cooling orifice 115.

[0081] The third cooling hole 115 can be configured to supply cooling fluid from the hollow portion 111 of the rotor shaft 100 to the bearing member 40, and can be formed at a position corresponding to the bearing member 40. The fourth cooling hole 116 can be configured to supply cooling fluid from the hollow portion 111 to the coil portion 50, and can be formed at a position corresponding to one side of the coil end 51. Furthermore, the dimensions of the third cooling hole 115 and the diameter of the fourth cooling hole 116 can be the same or different. For example, as... Figure 4 As shown, the diameter of the third cooling hole 115 can be larger than the diameter of the fourth cooling hole 116.

[0082] Multiple third cooling holes 115 and multiple fourth cooling holes 116 may be spaced apart from each other along the circumferential direction of the shaft 110. Here, four third cooling holes 115 and four fourth cooling holes 116 may be arranged along the circumferential direction of the shaft 110, but this disclosure is not limited thereto.

[0083] In the direction from the support flange 130 toward one axial end of the shaft 110, the second cooling hole 114, the first cooling hole 113, the fourth cooling hole 116 and the third cooling hole 115 can be arranged in sequence.

[0084] For example, the shaft 110 may include a rotor mounting portion corresponding to the position of the assembled rotor core 200; a base plate mounting portion disposed on one side of the rotor mounting portion and corresponding to the position of the assembled first end plate 310; a bearing mounting portion corresponding to the position of the mounted bearing 40; and a coil end arrangement portion disposed between the base plate mounting portion and the bearing mounting portion and corresponding to the position of the coil end 51 on one side.

[0085] Furthermore, the first cooling hole 113 may be formed at one axial end of the rotor mounting portion, and the second cooling hole 114 may be formed at the center of the rotor mounting portion along the axial direction of the shaft 110. Additionally, the third cooling hole 115 may be formed at the bearing mounting portion, and the fourth cooling hole 116 may be formed in the coil end arrangement portion.

[0086] The rotor assembly 10 according to embodiments of the present disclosure may include a first end plate 310 and a second end plate 320.

[0087] The first end plate 310 can be configured to cover one axial end of the rotor core 200. The second end plate 320 can be configured to cover the opposite axial end of the rotor core 200. For example, the first end plate 310 can be mounted on the rear side of the rotor assembly 10, while the second end plate 320 can be mounted on the front side of the rotor assembly 10.

[0088] Specifically, the first end plate 310 may include a suction hole 313 and a first channel groove 311.

[0089] The suction hole 313 can be formed to communicate with the first cooling hole 113. For example, the suction hole 313 can extend radially from the inner surface of the first end plate 310 toward the first end plate 310, and a plurality of suction holes 313 can be formed spaced apart from each other in the circumferential direction of the first end plate 310. Since the suction holes 313 are formed in a position and number corresponding to the first cooling hole 113, they can communicate with the first cooling hole 113.

[0090] The first channel groove 311 is recessed on the surface of the rotor core 200 facing the first end plate 310 and is formed along the circumferential direction of the rotor shaft 100. It can be connected to the suction port 313 and can communicate with the rotor cooling channel 220. For example, the first channel groove 311 can have an annular shape connecting multiple suction ports 313.

[0091] Therefore, the cooling fluid discharged from the first cooling hole 113 can be introduced into the first channel groove 311 through the suction hole 313, and the cooling fluid introduced into the first channel groove can be introduced into the rotor cooling channel 220.

[0092] At the same time, it will refer to Figure 9-12 The second end plate 320 is described in detail below. For ease of description, the surface of the rotor core 200 facing the second end plate 320 will be referred to as the first surface, and the surface opposite to the first surface will be referred to as the second surface.

[0093] The second end plate 320 may include a second channel groove 321 and a discharge hole 323.

[0094] The second channel groove 321 is recessed on the first surface of the second end plate 320 and is formed along the circumferential direction of the rotor shaft 100, and can communicate with the rotor cooling channel 220. A discharge hole 323 can be formed to pass between the second channel groove 321 and the second surface to discharge introduced cooling fluid into the second channel groove 321.

[0095] Specifically, the second channel groove 321 may be formed in an annular shape on the first surface to connect the ends of the plurality of rotor cooling channels 220. In addition, a plurality of discharge holes 323 may be formed along the circumferential direction of the second end plate 320 to be spaced apart from each other.

[0096] Therefore, the cooling fluid flowing in the rotor cooling channel 220 can be introduced into the second channel groove 321, and the cooling fluid introduced into the second channel groove 321 can be discharged to the opposite coil end 52 through the discharge hole 323. In the embodiments of this disclosure, since the second end plate 320 includes the second channel groove 321 and the discharge hole 323 communicating with the rotor cooling channel 220, the cooling fluid introduced into the hollow portion 111 of the rotor shaft 100 can be guided to the opposite coil end 52 to directly cool the coil portion 50.

[0097] Here, the discharge hole 323 can be formed at an angle away from the rotor shaft 100 as it travels from the second channel groove 321 in a direction facing the second surface.

[0098] Reference Figure 11 and 12 Since the discharge hole 323 is formed at an angle away from the rotor shaft 100, the cooling fluid discharged through the discharge hole 323 can be sprayed onto the opposite end of the opposite coil end 52. Thus, since the discharge hole 323 is formed at an angle from the second channel groove 321 toward the opposite coil end 52, the opposite coil end 52 can be cooled more effectively.

[0099] Specifically, the temperature of the coil portion 50 increases as it travels towards one coil end 51 and the opposite coil end 52, and further increases as it travels towards the axial end of the opposite coil end 52. However, when the discharge hole 323 is formed radially extending from the second channel groove 321 instead of being inclined toward the second surface, the cooling fluid is not directly sprayed onto the opposite ends of the opposite coil ends 52, resulting in a relatively low cooling effect on the opposite side of the opposite coil ends 52. In this case, the cooling fluid discharged from the discharge hole 323 can be sprayed onto the region of the coil portion 50 corresponding to the position of the second end plate 320. Meanwhile, in the embodiments of this disclosure, since the discharge hole 323 is formed toward the second surface and is formed to be inclined away from the rotor shaft as it travels toward the second surface, the cooling fluid is directly sprayed onto the opposite coil end 52, thereby increasing the cooling rate.

[0100] Meanwhile, the flow of cooling fluid discharged from a plurality of cooling holes in the cooling fluid orifice section will be described with reference to the illustrated embodiment.

[0101] First, cooling fluid supplied from a cooling fluid supply source can be introduced into the hollow portion 111 through an oil inlet 112 formed on one side of the shaft 110. The introduced cooling fluid can flow from one side of the shaft 110 in the axial direction towards the opposite side.

[0102] A portion of the introduced cooling fluid can be discharged through the third cooling hole 115 and can be sprayed onto the bearing component 40. Therefore, the cooling fluid can be used as a lubricant for the bearing component 40 and can also directly cool the bearing component 40.

[0103] In addition, a portion of the cooling fluid can be discharged through the fourth cooling hole 116, and can be sprayed onto one side coil end 51 by the rotational force of the rotor shaft 100. Therefore, one side coil end 51 can be directly cooled by the cooling fluid.

[0104] Furthermore, a portion of the cooling fluid can be discharged through the first cooling hole 113 and introduced into the rotor cooling channel 220 through the suction hole 313 and the first channel groove 311. Therefore, the rotor core 200 can be directly cooled by the cooling fluid. The cooling fluid passing through the rotor cooling channel 220 can be discharged towards the opposite coil end 52 through the second channel groove 321 and the discharge hole 323 of the second end plate 320. Therefore, the opposite coil end 52 can be directly cooled by the cooling fluid.

[0105] Furthermore, a portion of the cooling fluid can be discharged through the second cooling hole 114 and introduced into the channel portion 135 of the support flange 130 and the stator cooling channel 230. The cooling fluid introduced into the stator cooling channel 230 can flow along the direction facing the inner surface of the stator 30 due to the rotational force of the rotor shaft 100 during rotation, thus the middle region of the stator 30 can be directly cooled by the cooling fluid. Then, during the flow of the cooling fluid introduced into the stator cooling channel 230, the rotor core 200 can be additionally cooled.

[0106] Thus, according to embodiments of this disclosure, by improving the structure of the rotor core 200 and the rotor shaft 100, components that are difficult to cool directly in existing oil cooling systems can be cooled directly without adding additional components.

[0107] Therefore, the efficiency of the motor 1 according to the embodiments of this disclosure can be improved by increasing the cooling efficiency. Furthermore, since the magnets mounted on the rotor core 200 can be cooled by the efficient cooling of the rotor core 200, the specifications of the magnets can be reduced, thereby achieving the effect of reducing manufacturing costs.

[0108] Furthermore, according to an embodiment of the present invention, since one side coil end 51 and the opposite side coil end 52 can be directly cooled through the fourth cooling hole 116 and the second end plate 320, the installation of the circular oil pipe normally used for cooling can be omitted, and the machining of the housing for installation can also be omitted. Therefore, the number of parts can be reduced and the housing machining process can be omitted, thereby achieving the effect of reducing manufacturing costs.

[0109] Thus, the rotor assembly and the motor including it according to this disclosure can directly cool parts that are difficult to cool directly by existing oil cooling systems without adding additional components, through improvements to the structure of the rotor core and rotor shaft.

[0110] Therefore, the motor according to the embodiments of this disclosure can improve its efficiency by increasing cooling efficiency. Furthermore, since the magnets mounted on the rotor core can be cooled efficiently, the specifications of the magnets can be reduced, thereby achieving the effect of reducing manufacturing costs.

[0111] Although specific embodiments of the present disclosure have been described herein, the spirit and scope of the present disclosure are not limited to the specific embodiments. Various modifications and alterations can be made to the present disclosure by those skilled in the art without changing the essence of the present disclosure as claimed in the claims.

Claims

1. A rotor assembly, comprising: The rotor core has a through hole disposed at its central portion along the axial direction of the rotor core; as well as The rotor shaft is configured to pass through the through-hole and be coupled to the rotor core. The rotor shaft includes: The shaft has a hollow interior. A cooling fluid perforation section includes a plurality of cooling holes passing through the shaft body to discharge cooling fluid introduced through the hollow portion to the outside of the shaft body, the plurality of cooling holes being arranged spaced apart from each other along the axial direction of the shaft body; and A support flange, protruding radially from the outer surface of the shaft body, restricts axial movement of the rotor core and has a channel communication hole. The rotor core includes: A rotor cooling channel, extending axially in the rotor core and communicating with some of the plurality of cooling holes, is configured to pass through the channel communication holes and to allow the cooling fluid to flow through it. The rotor core includes: Multiple core components are stacked along the axial direction of the rotor core and configured to form the rotor cooling channel in the stacked state of the multiple core components. The supporting flange is inserted between adjacent core components of the plurality of core components; The cooling fluid orifice includes: A first cooling hole is located at a position corresponding to one axial end of the rotor core and communicates with the rotor cooling channel; and The second cooling hole is located on the opposite side of the first cooling hole, spaced apart from the first cooling hole, and located at a position corresponding to the support flange; Furthermore, the rotor assembly also includes: A first end plate is configured to cover one axial end of the rotor core; and The second end plate is configured to cover the opposite axial end of the rotor core; The first end plate includes: The intake port communicates with the first cooling port; and The first channel groove is concave on the surface of the first end plate facing the rotor core, is arranged along the circumferential direction of the rotor shaft, is connected to the suction hole, and communicates with the rotor cooling channel.

2. The rotor assembly according to claim 1, wherein, The first cooling holes are spaced apart from each other along the circumferential direction of the shaft, and The second cooling holes are spaced apart from each other along the circumferential direction of the shaft.

3. The rotor assembly according to claim 1, wherein, The supporting flange includes: Support body, having the channel communication hole; and The channel portion has a cutout shape at a part of the support body and extends radially from the shaft body to communicate with the second cooling hole, and The rotor core further includes: Stator cooling channels extend radially between adjacent cores of the plurality of cores, are disposed in a region corresponding to the channel portion, and are configured such that the cooling fluid discharged through the second cooling hole flows radially.

4. The rotor assembly according to claim 1, wherein, The second end plate includes a first surface facing the rotor core and a second surface opposite to the first surface, and The second end plate includes: The second channel groove is concave on the first surface of the second end plate, arranged along the circumferential direction of the rotor shaft, and communicates with the rotor cooling channel; and A discharge port extends through the second end plate and between the second channel groove and the second surface to discharge the cooling fluid introduced into the second channel groove.

5. The rotor assembly according to claim 4, wherein, As the discharge hole extends from the second channel groove in a direction toward the second surface, the discharge hole is tilted away from the rotor shaft.

6. The rotor assembly according to claim 1, wherein, The cooling fluid orifice includes: A third cooling hole is disposed on one side of the first cooling hole and spaced apart from the first cooling hole; and The fourth cooling hole is located between the first cooling hole and the third cooling hole.

7. The rotor assembly according to claim 6, wherein, The third cooling holes are spaced apart from each other along the circumferential direction of the shaft, and The fourth cooling holes are spaced apart from each other along the circumferential direction of the shaft.

8. An electric motor, comprising: case; The stator is disposed inside the housing; as well as A rotor assembly according to claim 1, rotatable and installed inside the stator.

9. The motor according to claim 8, wherein, The supporting flange includes: Support body, having the channel communication hole; and The channel portion has a cutout shape at a part of the support body and extends radially from the shaft body to communicate with some of the plurality of cooling holes. The rotor core further includes: Multiple core components are stacked along the axial direction of the rotor core and configured to form the rotor cooling channel in the stacked state of the multiple core components. Stator cooling channels extend radially between adjacent cores in the plurality of cores, are disposed in a region corresponding to the channel portion, and are configured such that the cooling fluid discharged through some of the cooling holes flows radially.

10. The motor according to claim 8, further comprising: The coil section is located inside the stator. Among these, some of the multiple cooling holes are located at positions corresponding to the coil section, and The cooling fluid flowing through the rotor cooling channel is discharged toward the opposite end of the coil section.

11. The motor according to claim 8, further comprising: A bearing component installed at one end of the rotor shaft, and Some of the multiple cooling holes are located at positions corresponding to the bearing component.

Images