Rotor module with cooling structure

Abstract

Rotor module with a cooling structure, comprising: a rotor core arranged in a hollow cylindrical shape; a rotor shaft that is fixedly inserted into the center of the rotor core and rotates around a central axis of the rotor core; and a cooling flow path unit located in the rotor core and rotor shaft through which cooling oil flows, wherein the cooling flow path unit comprises at least a first flow path which is recessed in a groove shape in an outer surface of the rotor shaft and extends in an axial direction of the rotor shaft.

Description

Background of the Revelation; Area of ​​the Revelation

[0001] The present disclosure relates to a rotor module used in a vehicle, and in particular to a rotor module with a cooling structure. Description of the state of the art

[0002] Since the heat generation of permanent magnets has recently increased with the speed of a motor, adequate cooling of the rotor is essential to prevent a reduction in motor efficiency. Conventional hollow shafts are used for motor cooling and for lubricating a reduction gear by utilizing centrifugal force as much as possible through a hollow structure and machined flow path holes. That is, cooling is achieved by supplying oil from the center of rotation and distributing the oil, subjected to centrifugal force, along the outer diameter of the core through the holes.

[0003] However, the conventional axial rotor, unlike the off-axis rotor, has a problem in that, since a drive shaft is located inside a rotor shaft, the utilization of the internal space is limited, and if the interior of the hollow shaft is used as a flow path, the rotational efficiency of the drive shaft can be reduced. More specifically, the hollow shaft of the off-axis type does not provide cooling for the rotor. While the hollow shaft was used to address NVH (noise, vibration, and harshness) problems and reduce weight, with the advancement of engine power, heat generation in the rotor has not become a serious concern.Initially, the axial hollow shaft also lacks a cooling function for the rotor and adopts a structure where a drive shaft passes through the hollow shaft. However, with the improved performance of permanent magnets, heat generation and loss problems arise in the rotor, highlighting the need for cooling. To address this need, the axial hollow shaft incorporates a method of injecting oil into the hollow shaft to cool the rotor. However, since the drive shaft, which rotates inside the hollow shaft, and the cooling oil share the same space, there is concern that the rotation of the shaft could be impeded, leading to a reduction in drive efficiency. State of the art documents

[0004] (Patent document 1) Korean patent application no. 10-2024-0081340 (“MOTOR COOLING STRUCTURE”; “Motor cooling structure”) Summary of Revelation

[0005] The present disclosure was made in an effort to solve the aforementioned problems and is directed to provide a rotor module with a cooling structure in which a flow path can be formed on an outer surface of a rotor shaft, thereby creating an oil supply path from a hollow shaft to a rotor core, addressing a heat generation problem and a demagnetization problem by directly cooling the rotor core, and enabling both oil supply and lubrication for a coupling of a reduction gear and a needle roller bearing (NRB) of a planetary gear, a Ravigneaux gear and the like.

[0006] According to one embodiment of the present disclosure, a rotor module is provided with a cooling structure comprising a rotor core formed in a hollow cylindrical shape, a rotor shaft fixedly inserted into a center of the rotor core and rotating about a central axis of the rotor core, and a cooling flow path unit formed in the rotor core and the rotor shaft through which cooling oil flows, wherein the cooling flow path unit comprises at least a first flow path recessed in a groove shape in an outer surface of the rotor shaft and extending in an axial direction of the rotor shaft.

[0007] Additionally, the cooling flow path unit can include a second flow path, which is a hole formed axially in the rotor core and one end of which is connected to the first flow path, and a third flow path, which is a hole formed axially in the rotor core and includes an outlet, one end of which is connected to the second flow path and the other end of which is connected to an outside of the rotor core.

[0008] Additionally, the other end of the third flow path can be formed at a location closer to the center of the rotor core than one end of the third flow path.

[0009] Additionally, the rotor core can have a magnet embedded therein, the magnet being provided in such a way that it has two or more layers spaced apart from each other in the radial direction of the rotor core, and the third flow path can be formed between the layers of the magnet.

[0010] Additionally, the cooling flow path unit may further comprise a tubular leakage prevention plate arranged between the rotor core and the rotor shaft, comprising an inner surface in contact with an outer surface of the rotor shaft.

[0011] Additionally, the leakage prevention plate may have connecting holes formed at points where the first flow path and the second flow path connect.

[0012] Additionally, the leakage prevention plate can be pressed onto the outer surface of the rotor shaft while hot.

[0013] Additionally, the cooling flow path unit may further include an oil guide, one end of which is coupled to one end of the rotor core and the other end of which extends towards the rotor shaft to cover a section of the outer surface of the rotor shaft, and which is provided to be spaced at a predetermined distance from the rotor shaft.

[0014] Additionally, the oil guide can include a fastening part, one end of which is coupled to the rotor core, and the fastening part can include a coupling section having a coupling hole designed to pass through in the axial direction of the rotor shaft and having a surface in contact with the rotor core, and a fastening element passing through both the coupling hole and the rotor core to fix the fastening part to the rotor core.

[0015] Additionally, the oil guide may further comprise a splash guard section designed to extend to cover the rotor shaft at the other end, and the splash guard section may comprise a first extension designed to extend from the mounting part and in the axial direction of the rotor shaft, and a second extension designed to extend from the first extension and in the radial direction of the rotor shaft.

[0016] Additionally, two or more first flow paths can be formed on a surface of the rotor shaft, and each of the first flow paths can have an end located at one end of the rotor shaft and have a different axial length. Brief description of the drawings Fig. Figure 1 is a perspective view showing a cross-section of a rotor module with a cooling structure of the present disclosure. Fig. Figure 2 is a partially perspective view showing a rotor shaft in which a first flow path is formed according to the present disclosure. Fig. Figure 3 is a partially perspective view showing a cross-section of the rotor module with the cooling structure of the present disclosure. Fig. 4 and Fig. Figure 5 are partially perspective views showing a rotor shaft to which a rotor module with a cooling structure according to a first embodiment of the present disclosure is applied. Fig. Figure 6 is a partial perspective view showing a rotor module with a cooling structure according to a second embodiment of the present disclosure. Fig. Figure 7 is a partial cross-sectional view showing the rotor module with the cooling structure according to the second embodiment of the present disclosure. Fig. Figure 8 is a partial perspective view showing a rotor module with a cooling structure according to a third embodiment of the present disclosure. Fig. Figure 9 is a partial perspective view showing an example of the application of a leakage prevention plate to the rotor module with the cooling structure according to the third embodiment of the present disclosure. Detailed description of the revelation

[0017] The technical teaching of the present disclosure is described in more detail below with reference to the accompanying drawings. In advance, terms or words used in this description and the claims should not be interpreted as being limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that correspond to the technical idea of ​​the present disclosure, based on the principle that the inventor can adequately define the concepts of the terms in order to describe his own disclosure in the best possible way.

[0018] The following describes a basic structure of a rotor module 1000 with a cooling structure of the present disclosure with reference to Fig. 1 to 3 described.

[0019] As in Fig. As shown in Figure 1, the rotor module 1000 with the cooling structure of the present disclosure can comprise a rotor core 100 and a rotor shaft 200. The rotor core 100 can be formed in a hollow cylindrical shape, and the rotor shaft 200 can be fixedly inserted into the center of the rotor core 100 and rotate about a central axis of the rotor core 100. Additionally, the rotor module 1000 with the cooling structure of the present disclosure can comprise a cooling flow path unit 300, which is formed in the rotor core 100 and the rotor shaft 200 and through which cooling oil flows. In this case, the cooling flow path unit 300 can direct the cooling oil in the direction indicated by the arrow in Figure 1. Fig. 1 flows.

[0020] In this case, as in Fig. As shown in Figure 2, the cooling flow path unit 300 comprises at least one first flow path 310, which is recessed in a groove shape in an outer surface of the rotor shaft 200 and extends in an axial direction along the rotor shaft 200. Two or more first flow paths 310 can be formed, and the locations of the first flow paths 310 can be easily modified depending on the arrangement of the rotor core 100, the rotor shaft 200, and adjacent components.The rotor module 1000 with the cooling structure of the present disclosure comprises a first flow path 310, which provides an oil supply path to the rotor core 100 when applied to the hollow rotor shaft 200, thereby addressing heat generation and demagnetization problems by directly cooling the rotor core 100 and enabling both oil supply and lubrication for a coupling of a reduction gear and a needle bearing (NRB) of a planetary gear, a Ravigneaux gear and the like.

[0021] Additionally, as in Fig. As shown in Figure 3, the cooling flow path unit 300 comprises a second flow path 320 and a third flow path 330, which are connected to the first flow path 310 and allow cooling oil to flow into the rotor core 100. More precisely, the second flow path 320 is a hole formed radially in the rotor core 100, one end of which can connect to the first flow path 310. Accordingly, the cooling oil, which has cooled the rotor shaft 200 as it flows along the first flow path 310, can move radially outward along the second flow path 320, i.e., inward from the rotor core 100, due to a centrifugal force when the rotor shaft 200 rotates.The third flow path 330 is a hole formed axially in the rotor core 100 and may include an outlet 331, one end of which is connected to the other end of the second flow path 320 and the other end of which is connected to the outside of the rotor core 100.

[0022] In this way, since the cooling flow path unit 300 additionally comprises the second flow path 320 and the third flow path 330, the cooling oil introduced through the first flow path 310 can flow into the rotor core 100 to simultaneously cool the rotor shaft 200 and the rotor core 100. Additionally, by arranging the outlet 331 of the third flow path 330 at the end of the rotor core 100, the cooling oil can also be sprayed onto components such as a clutch, a gearbox, and a bearing of the reduction gear provided at the end of the rotor core 100, thereby achieving both cooling and lubrication effects.

[0023] Furthermore, the outlet 331 of the third channel 330 can be located at the other end at a position closer to the center of the rotor core 100 than either end of the third channel 330. That is, a step can be formed upstream of the outlet 331 in the cooling oil flow direction. Accordingly, the cooling oil exiting the outlet 331 at the other end of the third flow path 330 can flow towards the central axis of the rotor core 100 and the rotor shaft 200, thereby spraying the cooling oil onto gears and bearings.

[0024] Additionally, the rotor core 100 can have an embedded magnet 110, which has two or more layers spaced apart from each other in the radial direction of the rotor core 100. In this case, the third flow path 330 can be formed between the layers of each magnet 110. Accordingly, the magnet 110, which is the main heat-generating component, can be cooled more efficiently.

[0025] The rotor module 1000 with a cooling structure according to a first embodiment of the present disclosure is described in more detail below with reference to Fig. 4 and Fig. 5 described.

[0026] In the rotor module 1000 with the cooling structure according to the first embodiment of the present disclosure, as described in Fig. As shown in Figure 4, the cooling flow path unit 300 further comprises a leakage prevention plate 340, which is arranged between the rotor core 100 and the rotor shaft 200, has an inner surface in contact with the outer surface of the rotor shaft 200, and is tubular in shape. The leakage prevention plate 340 can be formed by machining a steel plate. By including the leakage prevention plate 340, a space can be formed in which the cooling oil flows through the leakage prevention plate 340 and the first flow path 310. Even if an inner surface of the rotor core 100 is not flat, and thus the leakage prevention plate 340 cannot form the space in which the cooling oil will flow between it and the first flow path 310, the leakage prevention plate 340 can still form a space in which the cooling oil moves axially between it and the first flow path 310.

[0027] In this case, the leakage prevention plate 340 is preferably hot-pressed onto the outer surface of the rotor shaft 200. Accordingly, the leakage prevention plate 340 and the rotor shaft 200 can be more tightly coupled, and it can be prevented that the cooling oil escapes from the first flow path 310 between the rotor shaft 200 and the leakage prevention plate 340.

[0028] Additionally, the leakage prevention plate 340, as shown in Fig. Figure 5 shows connection holes 341, which are perforated at the points where the first flow path 310 and the second flow path 320 communicate with each other. Accordingly, even when the leakage prevention plate 340 is pressed in, the first flow path 310 and the second flow path 320 remain in contact with each other to allow the cooling oil to be transferred to the rotor core 100.

[0029] The rotor module 1000 with a cooling structure according to a second embodiment of the present disclosure is described in more detail below with reference to Fig. 6 and Fig. 7 described.

[0030] In the rotor module 1000 with the cooling structure according to the second embodiment of the present disclosure, as described in Fig. As shown in Figure 6, the cooling flow path unit 300 further comprises an oil guide 350, one end of which is coupled to an end of the rotor core 100 and the other end of which extends towards the rotor shaft 200 to cover a portion of the outer surface of the rotor shaft 200, and which is positioned at a predetermined distance from the rotor shaft 200. More precisely, the oil guide 350 can be coupled to an end of the rotor core 100 or the rotor shaft 200 that is formed at locations where a bearing, a reservoir, a bracket, and the like are inserted.The cooling oil can be sprayed onto the end of the rotor shaft 200 or the rotor core 100, to which the oil guide 350 is applied, through one of the conventional O-shaped tubes or a direct spray opening of the reduction gear, and in this case the oil guide 350 can serve to direct the flow of the cooling oil to prevent the cooling oil from scattering, or to collect the sprayed cooling oil.

[0031] More precisely, as in Fig. As shown in Figure 7, the oil guide 350 comprises a fastening part 351, one end of which is coupled to the rotor core 100, and the fastening part 351 can include a coupling section 351a and a fastening element 351c of the rotor shaft 200. More precisely, the coupling section 351a can have a coupling hole 351b, which is configured to extend axially through the rotor core 100 and has a surface in contact with the rotor core 100. In this case, the coupling section 351a can come into contact with a surface of one of several ends formed on the rotor core 100, and the rotor core 100 can have a hole of the same size formed at a location corresponding to the location of the coupling hole 351b. Additionally, the fastening element 351c can pass through both the coupling hole 351b and the rotor core 100 to fix the fastening part 351 to the rotor core 100.

[0032] Additionally, the oil guide 350 can further comprise a splash guard section 352, the other end of which is configured to extend to cover the rotor shaft 200. The splash guard section 352 can comprise a first extension 352a and a second extension 352b, which are formed integrally. More precisely, the first extension 352a can be configured to extend from the mounting part 351 and to extend in the axial direction of the rotor shaft 200, and the second extension 352b can be configured to extend from the first extension 352a and to extend in the radial direction of the rotor shaft 200.In this way, by including the vertically curved scatter protection section 352, it is possible to prevent the cooling oil from scattering due to the centrifugal force of the shaft during oil injection, thereby facilitating the injection of the cooling oil.

[0033] A third embodiment of the present disclosure is described in more detail below with reference to Fig. 8 and Fig. 9 described.

[0034] As in Fig. As shown in Figure 8, two or more first flow paths 310 can be formed on the surface of the rotor shaft 200, each having a different axial length. In this case, one end of each first flow path 310 can be located at one end of the rotor shaft 200. Accordingly, the spray direction of the coolant flowing along the first flow path 310 can be different to allow the coolant to be sprayed at different locations.

[0035] In this case, as in Fig. Figure 9 shows that the leakage prevention plates 340 of the third embodiment and the first embodiment are coupled. In this case, the connecting holes 341 of the leakage prevention plate 340 can be formed at locations corresponding to the other ends of each first flow path 310 to allow the coolant to escape from the end of each first flow path 310.

[0036] With such a configuration, the rotor module with a cooling structure can be designed to form a flow path on an outer surface of a rotor shaft, thereby creating an oil supply path from a hollow-type shaft to a rotor core, addressing a heat generation problem and a demagnetization problem by directly cooling the rotor core, and enabling both oil supply and lubrication for a reduction gear coupling and a needle bearing (NRB) of a planetary gear, a Ravigneaux gear, and the like.

[0037] The technical teaching of the present disclosure should not be interpreted as being limited to the embodiments described above. Not only is the scope of application diverse, but various modifications can also be made by those skilled in the field without departing from the essence of the present disclosure as claimed in the claims. Accordingly, these improvements and modifications fall within the scope of the present disclosure, provided they are obvious to those skilled in the field.

[0038] The technical teaching of the present disclosure should not be interpreted as being limited to the embodiments described above. Not only is the scope of application diverse, but various modifications can also be made by those skilled in the field without departing from the essence of the present disclosure as claimed in the claims. Accordingly, these improvements and modifications fall within the scope of the present disclosure, provided they are obvious to those skilled in the field. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] KR 10-2024-0081340

[0004]

Claims

[1] Rotor module with a cooling structure, comprising: a rotor core arranged in a hollow cylindrical shape; a rotor shaft that is fixedly inserted into the center of the rotor core and rotates around a central axis of the rotor core; and a cooling flow path unit located in the rotor core and rotor shaft through which cooling oil flows, wherein the cooling flow path unit comprises at least a first flow path which is recessed in a groove shape in an outer surface of the rotor shaft and extends in an axial direction of the rotor shaft. [2] Rotor module according to claim 1, wherein the cooling flow path unit comprises: a second flow path in the form of a hole arranged axially in the rotor core, the second flow path comprising an end that is connected to the first flow path; and a third flow path in the form of a hole arranged axially in the rotor core and comprising an outlet, wherein the third flow path comprises one end that is connected to the second flow path and the other end that is connected to an outside of the rotor core. [3] Rotor module according to claim 2, wherein the other end of the third flow path is arranged at a location closer to the center of the rotor core than one end of the third flow path. [4] Rotor module according to claim 2 or 3, wherein the rotor core comprises a magnet embedded therein, wherein the magnet is provided such that it has two or more layers spaced apart from each other in a radial direction of the rotor core, and the third flow path is arranged between the layers of the magnet. [5] Rotor module according to one of claims 2 to 4, wherein the cooling flow path unit further comprises a tubular leakage prevention plate arranged between the rotor core and the rotor shaft and comprising an inner surface in contact with an outer surface of the rotor shaft. [6] Rotor module according to claim 5, wherein the tubular leakage prevention plate comprises connecting holes arranged at locations where the first flow path and the second flow path are connected to each other. [7] Rotor module according to claim 5 or 6, wherein the tubular leakage prevention plate is hot-pressed onto the outer surface of the rotor shaft. [8] Rotor module according to any one of claims 1 to 7, wherein the cooling flow path unit further comprises an oil guide comprising one end coupled to an end of the rotor core and the other end of which extends towards the rotor shaft to cover part of the outer surface of the rotor shaft and which is provided such that it has a predetermined distance from the rotor shaft. [9] Rotor module according to claim 8, wherein the oil guide comprises a fastening part with an end coupled to the rotor core, and the fastening part comprises: a coupling section with a coupling hole designed to pass through in the axial direction of the rotor shaft, and a surface in contact with the rotor core; and a fastening element that passes through both the coupling hole and the rotor core to fix the fastening part to the rotor core. [10] Rotor module according to claim 9, wherein the oil guide further comprises a scatter guard section designed to extend to cover the rotor shaft at the other end, and the scatter guard section comprises: a first extension, which is designed to extend from the fastening part and is designed to extend in the axial direction of the rotor shaft; and a second extension, designed to extend from the first extension and designed to extend in a radial direction along the rotor shaft. [11] Rotor module according to any one of claims 1 to 10, wherein two or more first flow paths are arranged on a surface of the rotor shaft, and each of the first flow paths comprises an end located at one end of the rotor shaft and has a different axial length.

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