Rotor module with cooling structure

Abstract

The invention relates to a rotor module with a cooling structure. Provided is a rotor, and more particularly, a rotor having improved cooling efficiency. The rotor module having the cooling structure of the present disclosure may more directly cool the rotor, thereby ensuring improved motor performance by the rotor directly equipped with the cooling structure including a cooling channel passing through the interior of the rotor core.

Description

Technical Field

[0001] The following disclosure relates to a rotor, and more particularly to a rotor having improved cooling efficiency. Background Art

[0002] The heat sources of the driving motor of an electric vehicle are a coil through which current flows and an electrical steel core through which magnetic flux flows. When the motor is running, the temperature of the corresponding parts may rise, and when the temperature rises excessively, a motor failure may occur. In order to prevent such a failure, it may be important to cool the heat source of the motor, and there are an oil cooling method of directly spraying oil onto the heat source of the motor, and a water cooling method of indirectly cooling the heat source by passing cooling water through a water channel portion of a housing.

[0003] Among these methods, the oil cooling method can be performed by a cooling pipe that sprays cooling oil to cool the heat of the stator as the main heating element and the components surrounding the stator. Here, the cooling oil dispersed through the cooling pipe can cool the motor as the heating element, and the oil heated by heat transfer can be stored on the bottom of the motor, and the oil stored on the bottom of the motor can be guided to the reducer through the inner housing channel connecting the motor with the reducer, and the oil can then be used to lubricate the reducer by stirring the reducer. In addition, the oil stored in the housing part of the reducer can be moved to an external heat exchanger by a pump, and the oil cooled by exchanging heat with cooling water can be circulated to cool the motor again.

[0004] When cooling is performed by this conventional oil cooling method of the drive motor, a separate cooling pipe is required for cooling, so more parts are required, and it is difficult to cool the deeper parts of the stator core and the rotor core. In addition, since the rotor core is covered by the plate and the stator core / coil, it is difficult to directly cool the rotor core when the oil is sprayed to the outside.

[0005] [Prior art literature]

[0006] [Patent Document]

[0007] (Patent Document 1) Korean Patent Laid-Open Publication No. 10-2022-0096306, entitled “Structure for projecting cooling oil” (published on December 31, 2020) Summary of the invention

[0008] Embodiments of the present disclosure are directed to providing a rotor module having a cooling structure that can cool a rotor more directly, thereby ensuring improved motor performance by directly providing a rotor with a cooling structure including a cooling channel passing through an interior of a rotor core.

[0009] In more detail, an embodiment of the present disclosure is intended to provide a rotor module with a cooling structure, which can ensure improved cooling performance by positioning a cooling channel in a rotor core so that the core and cooling oil are in direct contact with each other, and easily cool an outer magnet that is relatively difficult to cool by positioning a channel between the outer magnet and the inner magnet.

[0010] In addition, an embodiment of the present disclosure is intended to provide a rotor module with a cooling structure, which can solve the imbalance of cooling oil in the core and prevent noise, vibration and harshness (NVH) problems by installing outlet holes for oil outflow in a plate positioned at the end of the core and installing the outlet holes inward in a radial direction compared to the core channel.

[0011] In one general aspect, a rotor module with a cooling structure includes: a rotor core having an internally hollow cylindrical shape, the rotor core including a cooling channel portion; and a rotor shaft, the rotor shaft being fitted and fixed to the center of the rotor core to rotate around the central axis of the rotor core, the rotor shaft including a cooling fluid flow channel to be filled with a cooling fluid, wherein the cooling channel portion has one end connected to the cooling fluid flow channel and the other end connected to the outside of the rotor core.

[0012] The cooling channel portion may include: a first channel that passes through a side of the rotor shaft and disperses the cooling fluid from the cooling fluid flow channel to one end of the rotor core; and a second channel that passes through the rotor core in an axial direction and communicates with the first channel.

[0013] The cooling channel portion may further include a third channel having one end connected to the first channel and the other end connected to the second channel and positioned in a radial direction. The rotor core may further include a first plate, which is a flat plate having a first insertion hole at the center of the first plate, and the rotor shaft is inserted into the first insertion hole. The first plate may have a surface in contact with an end surface of the rotor core, and the third channel may be in a groove shape in a surface of the first plate.

[0014] The cooling channel portion may further include: a fourth channel having one end connected to the second channel and positioned in the radial direction; and a first fluid injection hole passing through the other end of the fourth channel. The rotor core may further include a second plate, which is a flat plate having a second insertion hole in the center of the second plate, and the rotor shaft is inserted into the second insertion hole. The second plate may have a surface in contact with the other end surface of the rotor core. The fourth channel may be in a groove shape in one surface of the second plate, and the first fluid injection hole may pass through the second plate in the axial direction.

[0015] A distance between the first fluid injection hole and a rotation axis of the rotor core may be shorter than a distance between the second passage and the rotation axis.

[0016] The length of the fourth channel may be greater than a sum of a diameter of the second channel and a diameter of the first fluid injection hole.

[0017] The cooling channel portion may further include: a fifth channel extending from one end of the third channel and communicating with the third channel; and a second fluid injection hole passing through a distal end of the fifth channel, the fifth channel may be in a groove shape in one surface of the first plate, and the second fluid injection hole may pass through the first plate in the axial direction.

[0018] A distance between the second fluid injection hole and the rotation axis of the rotor core may be shorter than a distance between the second channel and the rotation axis.

[0019] The cooling channel portion may further include: a sixth channel having one end communicating with one end of the second channel and positioned in the radial direction, the sixth channel being in the shape of a groove in the first plate; a fourth fluid injection hole passing through the first plate at the other end of the sixth channel; a seventh channel passing through the side of the rotor shaft to spread the cooling fluid from the cooling fluid flow channel to the other end of the rotor core; and an eighth channel having one end communicating with the seventh channel and the other end communicating with the second channel and positioned in the radial direction, the eighth channel being in the shape of a groove in the second plate.

[0020] The rotor module may further include a supply pipe, which supplies the cooling fluid into the cooling fluid flow channel, wherein the rotor shaft also includes: a first part, the first part includes the cooling fluid flow channel and an open side of the cooling fluid flow channel, wherein the rotor core is fitted to the side of the first part; a second part, the second part includes a press-fit portion positioned at one end of the second part, the press-fit portion is press-fitted to one side of the first part, wherein one end of the supply pipe is fitted to one end of the second part, and the supply pipe is fitted to the second part so that one end of the supply pipe is positioned closer to one end of the press-fit portion of the second part than the center of the cooling fluid flow channel in the axial direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a perspective view showing an axial cross section of a rotor module having a cooling structure of the present disclosure.

[0022] Figure 2 is an axial cross-sectional view of a rotor module having a cooling structure according to the present disclosure.

[0023] Figure 3 is a radial cross-sectional view of a rotor module having a cooling structure according to the present disclosure.

[0024] Figure 4 and Figure 5 is a partial cross-sectional view of a rotor module having a cooling structure of the present disclosure, showing a fourth channel.

[0025] Figure 6 is a plan view of a first plate of the present disclosure.

[0026] Figure 7 is a plan view of a second plate of the present disclosure.

[0027] Figure 8 is a partial perspective view of a rotor module having a cooling structure of the present disclosure, showing a protrusion.

[0028] Fig. 9 is an axial cross-sectional view of a rotor module having a cooling structure according to a first embodiment of a cooling channel portion of the present disclosure.

[0029] Fig.10 is a plan view of a first plate according to a first embodiment of a cooling channel portion of the present disclosure.

[0030] Fig.11 is a plan view of a second plate according to a second embodiment of a cooling channel portion of the present disclosure.

[0031] Fig.12is a plan view of a first plate according to a third embodiment of a cooling channel portion of the present disclosure.

[0032] Fig.13 is an axial cross-sectional view of a rotor module having a cooling structure according to a third embodiment of a cooling channel portion of the present disclosure.

[0033] Fig.14 is a plan view of a second plate according to a third embodiment of a cooling channel portion of the present disclosure.

[0034] Fig.15 is an axial cross-sectional view of a rotor module having a cooling structure according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0035] Hereinafter, the spirit of the present disclosure will be described in more detail with reference to the accompanying drawings. The terms and words used in the specification and claims should not be interpreted as general or dictionary meanings, but should be interpreted as meanings and concepts consistent with the spirit of the present disclosure, which is based on the principle that the inventor can appropriately define the concept of terms in order to best describe his invention.

[0036] In the following, the description refers to Figure 1 The basic configuration of the rotor module 1000 having the cooling structure of the present disclosure is described.

[0037] like Figure 1 As shown, the present disclosure may include a rotor core 100 and a rotor shaft 200. In more detail, the rotor core 100 may have a cylindrical shape with a hollow interior, and include a magnet generating an electric field therein. Here, the magnet may have two layers formed in a radial direction. In addition, the rotor shaft 200 may be fitted and fixed to the center of the rotor core 100, may rotate around the central axis of the rotor core 100, and may include a cooling fluid flow channel 230 filled with a cooling fluid.

[0038] Here, the rotor core 100 may include a cooling channel portion 110. The cooling channel portion 110 may have one end communicating with the cooling fluid flow channel 230 and the other end communicating with the outside of the rotor core 100. The cooling channel portion 110 may allow the cooling fluid to flow also in the rotor core, thereby more directly cooling the rotor, thereby ensuring improved motor performance.

[0039] In the following, reference will be made to Figures 2 to 5 The cooling channel portion 110 of the present disclosure is described in more detail.

[0040] like Figure 2As shown, the cooling channel portion 110 may include a first channel 111 and a second channel 112, the first channel 111 passing through the side of the rotor shaft 200 in the radial direction and distributing the cooling fluid from the cooling fluid flow channel 230 to the rotor core 100, and the second channel 112 passing through the rotor core 100 in the axial direction and communicating with the first channel 111. In more detail, the first channel 111 may be positioned to correspond to one end of the rotor core 100, and two or more first channels 111 may be positioned on the side of the rotor shaft 200 in the circumferential direction. The cooling channel portion 110 including the first channel 111 and the second channel 112 may allow the fluid flowing in the cooling fluid flow channel 230 to flow out of the rotor shaft 200 and flow through the inside of the rotor core 100, which may cool the rotor more directly, thereby ensuring improved motor performance.

[0041] In addition, if Figure 3 As shown, the second channel 112 may be positioned between the outer magnet 140 and the inner magnet 150 inserted into the rotor core 100, and two or more second channels 112 may be positioned on the side of the rotor core 100 in the circumferential direction. That is, the distance between the second channel 112 and the rotation axis of the rotor core 100 may be shorter than the distance between the outer magnet 140 of the rotor core 100 and the rotation axis, and may be longer than the distance between the inner magnet 150 of the rotor core 100 and the rotation axis. Therefore, the cooling channel portion 110 may easily cool the outer magnet 140, which is relatively difficult to cool.

[0042] In addition, the cooling channel portion 110 may include a third channel 113 that communicates the first channel 111 with the second channel 112. In more detail, the third channel 113 may have one end communicating with the first channel 111 and the other end communicating with the second channel 112, and may be positioned in the radial direction. In one embodiment, the third channel 113 may be positioned at the rotor core 100 or may be positioned at the first plate 120. The first plate 120 is described below.

[0043] In addition, the cooling channel portion 110 may include a fourth channel 114 having one end communicating with the second channel 112 and positioned in the radial direction, and a first fluid injection hole 115 passing through the other end of the fourth channel 114. In one embodiment, the fourth channel 114 may be positioned at the rotor core 100 or may be positioned at the second plate 130. The second plate 130 is described below. Here, the third channel 113 and the fourth channel 114 may be positioned at opposite sides of the rotor core 100, respectively. That is, the third channel 113 and the first channel 111 communicating with the third channel 113 may be positioned at one end of the rotor core 100, and the fourth channel 114 may be positioned at the other end of the rotor core 100.

[0044] That is, the cooling fluid may flow out of the rotor shaft 200 from the cooling fluid flow channel through the first channel 111, then move to the opposite side of the rotation axis (i.e., in the radial direction) through the third channel 113, pass through the rotor core 100 in the axial direction through the second channel 112, and may move toward the rotation axis again through the fourth channel 114 after completely filling the second channel 112. The fluid may be ejected to the outside through the first fluid ejection hole 115. Therefore, as Figure 4 As shown, the first fluid injection hole 115 may be positioned such that a distance R2 between the first fluid injection hole and the rotation axis of the rotor core 100 is shorter than a distance R1 between the second passage 112 and the rotation axis.

[0045] According to the construction of the cooling channel portion 110 as described above, the fluid flowing in the cooling channel portion 110 can move back toward the rotation axis through the fourth channel 114 just before flowing out of the rotor core 100, thereby preventing the cooling fluid from being pushed to the outside of the channel due to the centrifugal force of the continuously rotating rotor core 100, and ultimately preventing noise, vibration and harshness (NVH) problems from being generated due to unbalanced flow of oil in the core.

[0046] In addition, if Figure 5 As shown, the length L of the fourth channel 114 may be greater than the sum of the diameter d1 of the second channel 112 and the diameter d2 of the first fluid injection hole 115. That is, a certain gap may be formed between the second channel 112 and the first fluid injection hole 115, thereby maximizing the effect of the fourth channel 114 and preventing the cooling fluid from being injected through the first fluid injection hole 115 before the fluid completely fills the second channel 112. Therefore, the fluid may flow uniformly along the second channel 112 located in the core, thereby also constantly maintaining the flow rate injected through the first fluid injection hole 115.

[0047] Below, refer to Figures 6 to 8 The first plate 120 and the second plate 130 of the present disclosure are described in more detail.

[0048] The rotor core 100 may include a first plate 120 which is a flat plate stacked on one end surface. Figure 6As shown, the first plate 120 may have a first insertion hole 121 formed at the center thereof, and the rotor shaft 200 is inserted into the first insertion hole 121. The first plate 120 may have a third channel 113 formed in a groove shape in one surface in contact with one end surface of the rotor core 100. The third channels 113 may be positioned in the first plate 120, and the same number of third channels 113 as the number of first channels 111 and second channels 112 may be spaced apart from each other at regular intervals. The rotor core 100 may include the first plate 120, which is a flat plate, in which the third channels 113 are formed as a separate component therefrom, thereby preventing interference between the outer magnets 140 and the inner magnets 150 of the rotor core 100 and the third channels 113.

[0049] In addition, if Figure 7 As shown, the rotor core 100 may include a second plate 130 having a second insertion hole 132 formed at the center of the second plate 130 and into which the rotor shaft 200 is inserted. The second plate 130 may have one surface in contact with the other end surface of the rotor core 100, and the fourth channel 114 may be formed in a groove shape in one surface of the second plate 130 in contact with the rotor core 100. The first fluid injection hole 115 may pass through the second plate 130 in the axial direction. The same number of the fourth channel 114 and the first fluid injection hole 115 as the number of the second channel 112 may be provided.

[0050] In addition, if Figure 8 As shown, the second plate 130 may include a protrusion 131 protruding along the circumferential direction of the second insertion hole 132. Here, the area where the protrusion 131 protrudes may overlap at least a portion of the area through which the first fluid injection hole 115 passes. Therefore, the groove may be positioned in the side of the protrusion 131 as large as the depth of the area where the first fluid injection hole 115 is positioned. Therefore, the cooling fluid injected through the first fluid injection hole 115 may be injected to the opposite side of the rotation axis, and the outer surface of the rotor core 100 may be cooled more effectively.

[0051] In the following, reference is made to Fig. 9 and Fig.10 The first embodiment of the cooling channel portion 110 is described in more detail.

[0052] like Fig. 9 As shown, the cooling channel portion 110 may include a fifth channel 116 extending from one end of the third channel 113 and communicating with the third channel 113, and a second fluid injection hole 117 passing through a distal end of the fifth channel 116. Fig.10As shown, the fifth channel 116 may be formed in a groove shape in one surface of the first plate 120 and may extend from the third channel 113. The second fluid injection hole 117 may penetrate the first plate 120 in the axial direction. Therefore, the fluid may flow uniformly along the second channel 112 located at the core, thereby also constantly maintaining the flow rate injected through the first fluid injection hole 115.

[0053] In addition, the fifth channel 116 may be bent to form a U-shape with the third channel 113, and the second fluid injection hole 117 may be spaced apart from the third channel 113 at a predetermined interval in the circumferential direction. Therefore, the cooling fluid entering the third channel 113 may be separated into a portion flowing into the second channel 112 and another portion flowing into the fifth channel 116. As a result, the cooling fluid may be injected while being divided into both sides of the rotor core 100.

[0054] Here, the distance between the second fluid injection hole 117 and the rotation axis of the rotor core 100 may be shorter than the distance between the second channel 112 and the rotation axis. In detail, the distance between the second fluid injection hole 117 and the rotation axis of the rotor core 100 may be the same as the distance between the first fluid injection hole 115 and the rotation axis of the rotor core 100. Therefore, the fluid may be injected at the same flow rate on both sides of the rotor core 100, thereby uniformly cooling the rotor core 100.

[0055] Below, refer to Fig.11 The second embodiment of the cooling channel portion 110 is described in more detail.

[0056] like Fig.11 As shown, the cooling channel portion 110 may include a third fluid injection hole 118 passing through the third channel 113. In more detail, the third fluid injection hole 118 may be spaced apart from the other end of the third channel 113 (i.e., toward a position where one end of the third channel 113 communicates with the second channel 112) by a predetermined interval. Here, the third fluid injection hole 118 may pass through the first plate 120 in the axial direction. When the second embodiment of the cooling channel portion 110 is used, the cooling fluid entering the third channel 113 may be separated into a portion flowing into the third fluid injection hole 118 and another portion flowing into the second channel 112. As a result, the cooling fluid may be injected while being divided into both sides of the rotor core 100.

[0057] Here, the distance between the third fluid injection hole 118 and the rotation axis of the rotor core 100 may be the same as the distance between the first fluid injection hole 115 and the rotation axis of the rotor core 100. That is, the distance between the other end of the third channel 113 and the third fluid injection hole 118 may be the same as the length of the fourth channel 114. Therefore, the cooling fluid may be prevented from being pushed to the outside of the channel due to the centrifugal force of the continuously rotating rotor core 100, and the fluid may be injected at the same flow rate on both sides of the rotor core 100, thereby uniformly cooling the rotor core 100.

[0058] Below, refer to Figure 12 to Figure 14 The third embodiment of the cooling channel portion 110 is described in more detail.

[0059] like Fig.12 As shown, the cooling channel portion 110 may include a sixth channel 119 and a fourth fluid injection hole 110a, the sixth channel 119 being positioned at the first plate 120, having one end communicating with one end of the second channel 112, and being positioned in the radial direction, and the fourth fluid injection hole 110a passing through the other end of the sixth channel 119. That is, at least a portion of one end of the second channel 112 may be communicated with the third channel 113, and the other portion may be communicated with the sixth channel 119 and the fourth fluid injection hole 110a.

[0060] In addition, if Fig.13 As shown, the cooling channel portion 110 may include a seventh channel 110b that passes through the side of the rotor shaft 200 in the radial direction and spreads the fluid from the cooling fluid flow channel 230 to the rotor core 100. The seventh channel 110b may correspond to the other end of the rotor core 100, that is, may be formed on the opposite side of the first channel 111.

[0061] In addition, if Fig.14 As shown, the cooling channel portion 110 may include an eighth channel 110c that communicates the seventh channel 110b with the other end of the second channel 112. In more detail, the eighth channel 110c may have one end communicating with the seventh channel 110b and the other end communicating with the other end of the second channel 112, and may be positioned in the radial direction. Here, the eighth channel 110c may be formed in a groove shape in the second plate 130, and at least a portion of the other end of the second channel 112 may be communicated with the eighth channel 110c, and another portion may be communicated with the fourth channel 114 and the first fluid injection hole 115.

[0062] Here, the fourth fluid injection hole 110a and the sixth channel 119 of the first plate 120 may be positioned in line with the seventh channel 110b of the second plate 130 in the axial direction, and the third channel 113 of the first plate 120 may be positioned in line with the first fluid injection hole 115 and the fourth channel 114 of the second plate 130 in the axial direction.

[0063] In addition, the number of the sixth channels 119 of the first plate 120 may be the same as the number of the third channels 113, and the number of the seventh channels 110b of the second plate 130 may also be the same as the number of the fourth channels 114. In addition, the sixth channels 119 and the third channels 113 may be arranged alternately with each other, and the seventh channels 110b and the fourth channels 114 may also be arranged alternately with each other.

[0064] like Fig.13 As shown, with this structure, the fluid can be injected at the same flow rate on both sides of the rotor core 100. However, unlike the first embodiment or the second embodiment of the cooling channel portion 110, the fluid injected in the cooling fluid flow channel 230 can flow through channels separated from each other in different directions, thereby preventing deviations in flow rate or pressure at the channel corresponding to the branch point (or the third channel 113) and preventing excessive use of the cooling fluid.

[0065] Below, refer to Fig.15 The rotor shaft 200 is described in more detail.

[0066] like Fig.15 As shown, the rotor module 1000 having the cooling structure of the present disclosure may further include a supply pipe 300 that supplies cooling fluid into the cooling fluid flow channel 230. Here, the supply pipe 300 may have one end fitted to the rotor shaft 200, and the cooling fluid supply hole 310 may be located in the side of the inserted end. In addition, the rotor shaft 200 may include a first portion 210 and a second portion 220, in which the rotor core 100 is fitted to one side, the cooling fluid flow channel 230 is positioned, and one side of the cooling fluid flow channel 230 is open, and in the second portion 220, a press-fit portion 221 is positioned at one end, the press-fit portion 221 is press-fitted to one side of the first portion 210, and one end of the supply pipe 300 is fitted to one end. Here, the supply pipe 300 may be fitted to the second portion 220 such that one end thereof (i.e., the cooling fluid supply hole 310) is positioned closer to one end of the press-fit portion 221 of the second portion 220 in the axial direction than the center of the cooling fluid flow channel 230. Therefore, the oil may be minimally isolated and smoothly flow into the core inlet.

[0067] As described above, the rotor module having the cooling structure of the present disclosure may cool the rotor more directly and thereby ensure improved motor performance by directly equipping the rotor with the cooling structure including the cooling passage passing through the inside of the rotor core.

[0068] In more detail, a rotor module having a cooling structure of the present disclosure can ensure improved cooling performance by positioning cooling channels in the rotor core so that the core and cooling oil are in direct contact with each other, and easily cool outer magnets that are relatively difficult to cool by positioning channels between the outer magnets and inner magnets.

[0069] In addition, the rotor module having the cooling structure of the present invention can solve the imbalance of cooling oil in the core and prevent noise, vibration and harshness (NVH) problems by installing outlet holes for oil outflow in a plate positioned at the end of the core and installing the outlet holes inward in the radial direction compared to the core channel.

[0070] The spirit of the present disclosure should not be limited to the above-mentioned embodiments. The present disclosure can be applied to various fields, and various modifications can be made by those skilled in the art without departing from the scope of the present disclosure claimed for protection by the claims. Therefore, it is obvious to those skilled in the art that these changes and modifications fall within the scope of the present disclosure.

Claims

1. A rotor module with a cooling structure, the rotor module comprising: a rotor core having an internally hollow cylindrical shape, the rotor core including a cooling channel portion; as well as a rotor shaft fitted and fixed to the center of the rotor core to rotate about the central axis of the rotor core, the rotor shaft including a cooling fluid flow channel to be filled with a cooling fluid, The cooling channel portion has one end communicating with the cooling fluid flow channel and the other end communicating with the outside of the rotor core.

2. The rotor module according to claim 1, wherein: The cooling channel portion comprises: a first passage that passes through a side of the rotor shaft to spread the cooling fluid from the cooling fluid flow passage to one end of the rotor core; and A second passage passes through the rotor core in an axial direction and communicates with the first passage.

3. The rotor module according to claim 2, wherein: The cooling channel portion further includes a third channel having one end communicating with the first channel and the other end communicating with the second channel and positioned in a radial direction, The rotor core further includes a first plate, the first plate being a flat plate having a first insertion hole at the center of the first plate, The rotor shaft is inserted into the first insertion hole, The first plate has one surface in contact with one end surface of the rotor core, and The third channel is in the shape of a groove in one surface of the first plate.

4. The rotor module according to claim 3, wherein: The cooling channel portion further includes: a fourth channel having one end communicating with the second channel and positioned along the radial direction; and a first fluid injection hole passing through the other end of the fourth channel, The rotor core further includes a second plate which is a flat plate having a second insertion hole at the center of the second plate, The rotor shaft is inserted into the second insertion hole, The second plate has one surface in contact with the other end surface of the rotor core, The fourth channel is in the shape of a groove in one surface of the second plate, and The first fluid injection hole penetrates the second plate in the axial direction.

5. The rotor module according to claim 4, wherein: A distance between the first fluid injection hole and a rotation axis of the rotor core is shorter than a distance between the second passage and the rotation axis.

6. The rotor module according to claim 4, wherein: The length of the fourth channel is greater than the sum of the diameter of the second channel and the diameter of the first fluid injection hole.

7. The rotor module according to claim 4, wherein: The cooling channel portion further includes: a fifth channel extending from one end of the third channel and communicating with the third channel; and a second fluid injection hole passing through a distal end of the fifth channel. The fifth channel is in the shape of a groove in one surface of the first plate, and The second fluid injection hole penetrates the first plate in the axial direction.

8. The rotor module according to claim 7, wherein: A distance between the second fluid injection hole and a rotation axis of the rotor core is shorter than a distance between the second passage and the rotation axis.

9. The rotor module according to claim 4, wherein: The cooling channel portion also includes: a sixth channel having one end communicating with one end of the second channel and positioned along the radial direction, the sixth channel being in a groove shape in the first plate; a fourth fluid injection hole, the fourth fluid injection hole penetrating the first plate at the other end of the sixth channel; a seventh passage penetrating a side of the rotor shaft to spread the cooling fluid from the cooling fluid flow passage to the other end of the rotor core; and An eighth channel having one end communicating with the seventh channel and the other end communicating with the second channel and positioned in the radial direction, the eighth channel being in a groove shape in the second plate.

10. The rotor module according to claim 1, further comprising a supply pipe that supplies the cooling fluid into the cooling fluid flow channel, in, The rotor shaft further comprises: a first portion including the cooling fluid flow passage and an open side of the cooling fluid flow passage, wherein the rotor core is fitted to a side of the first portion; and a second part, the second part including a press-fit portion positioned at one end of the second part, the press-fit portion being press-fitted to one side of the first part, wherein one end of the supply pipe is fitted to one end of the second part, and The supply pipe is fitted to the second portion such that one end of the supply pipe is located closer to one end of the press-fit portion of the second portion than to the center of the cooling fluid flow channel in the axial direction.

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