Oil-cooled motor rotor cooling structure and cooling method thereof

Abstract

A cooling structure and method for an oil-cooled motor rotor, belonging to the field of motor cooling technology. The motor rotor shaft has a rotor core and a dynamic balancing plate on its outer side, with the dynamic balancing plate fixed to both ends of the rotor core. An oil guide plate assembly is located in the middle of the rotor core. The rotor shaft has a central oil passage with a cooling oil inlet at its end. An oil outlet hole, communicating with the central oil passage, is radially opened on the side wall of the rotor shaft. The oil guide plate assembly has a cooling oil flow channel communicating with the oil outlet hole. The rotor core has an axially penetrating cooling channel whose inner end communicates with the cooling oil flow channel of the oil guide plate assembly. The outer end of the cooling channel communicates with the oil collection cavities of the two dynamic balancing plates. This invention achieves direct cooling of the rotor magnets, solving the problems of high thermal resistance and low cooling efficiency in traditional indirect cooling methods, and improving the reliability of motor operation.

Description

Technical Field

[0001] This invention relates to an oil-cooled motor rotor cooling structure and cooling method, belonging to the field of motor cooling technology. Background Technology

[0002] With the increasing demands for motor power density in new energy vehicles and industrial drive sectors, motor thermal management capabilities have become a key factor restricting motor performance improvement. Oil-cooled motors, with their advantages of good insulation and high heat transfer coefficient of the cooling medium, are gradually becoming the mainstream cooling solution for high power density motors.

[0003] Existing oil-cooled motor cooling technologies mostly focus on stator-side cooling, achieving stator heat dissipation through methods such as water cooling of the casing and oil spraying at the stator ends. However, there are significant technical shortcomings in cooling the rotor side, especially the interior of the rotor magnet slots. Traditional indirect cooling methods rely on the rotor core to conduct heat to transfer heat from the magnets to the cooling medium, resulting in high thermal resistance and low cooling efficiency, which cannot meet the heat dissipation requirements under high power density conditions. On the other hand, existing direct cooling solutions generally suffer from problems such as complex structure, poor sealing reliability, easy leakage of the cooling medium, poor compatibility with existing motor manufacturing processes, and unstable heat exchange processes.

[0004] During operation, the rotor magnets of an electric motor will generate significant eddy current losses. Under continuous operation at high power density, the rotor heat load increases sharply. Excessive temperature rise of the magnets can lead to irreversible demagnetization, which in turn can cause a decline in motor performance or even failure. Summary of the Invention

[0005] To address the problems existing in the background art, the present invention provides an oil-cooled motor rotor cooling structure and its cooling method.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: an oil-cooled motor rotor cooling structure, comprising a motor rotor shaft, a motor rotor core and two dynamic balancing plates fixedly sleeved on the outer side of the motor rotor shaft, the two dynamic balancing plates being respectively fixed to both ends of the motor rotor core; an oil guide plate assembly fixed in the middle of the motor rotor core, a central oil passage axially formed inside the motor rotor shaft, a cooling oil inlet at the end of the central oil passage, and an oil outlet hole radially formed on the side wall of the motor rotor shaft communicating with the internal central oil passage; a cooling oil flow channel communicating with the oil outlet hole of the motor rotor shaft on the oil guide plate assembly; and a cooling channel axially formed inside the motor rotor core, the inner end of which communicates with the cooling oil flow channel of the oil guide plate assembly, the outer end of which communicates with the oil collection cavities of the two dynamic balancing plates.

[0007] Furthermore, the oil guide plate assembly includes multiple axially symmetrical oil guide plate stamps, each of which has an independent cooling oil channel and is stacked together to form a multi-path parallel cooling oil flow channel.

[0008] Furthermore, the multiple oil guide plate stamps include at least a first type oil guide plate stamp, a second type oil guide plate stamp, and a third type oil guide plate stamp; the third type oil guide plate stamp is disposed in the middle, and the second type oil guide plate stamp and the first type oil guide plate stamp are symmetrically stacked on both sides of its axial direction.

[0009] Furthermore, the third type of oil guide plate has a spline-shaped mounting hole at its center that matches the motor rotor shaft; the third type of oil guide plate has N sets of third type oil guide plate inlet channels, N sets of wave-shaped bidirectional diversion channels and N sets of arc-shaped bidirectional diversion channels distributed along the circumferential direction. The N sets of wave-shaped bidirectional diversion channels and N sets of arc-shaped bidirectional diversion channels are arranged alternately, and the oil inlet of each set of third type oil guide plate inlet channels is connected to the corresponding motor rotor shaft oil outlet hole.

[0010] Furthermore, the second type of oil guide plate has a spline-shaped mounting hole at its center that matches the motor rotor shaft; the second type of oil guide plate has N sets of radial transition oil channels and 2N sets of arc-shaped connecting oil channels distributed along the circumferential direction. Each set of radial transition oil channels is axially aligned and connected to the corresponding third type of oil guide plate oil inlet channel, and each set of arc-shaped connecting oil channels is axially aligned and connected to the corresponding wave-shaped bidirectional diversion oil channel and arc-shaped bidirectional diversion oil channel.

[0011] Furthermore, the first type of oil guide plate has a spline-shaped mounting hole at its center that matches the motor rotor shaft; N sets of Y-shaped oil inlet channels and 2N sets of arc-shaped outer cooling oil channels are distributed along the circumferential direction on the first type of oil guide plate; the main part of each set of Y-shaped oil inlet channels is axially aligned and connected to the corresponding radial transition oil channel, and the two branches of each set of Y-shaped oil inlet channels and each set of arc-shaped outer cooling oil channels are axially aligned and connected to the corresponding arc-shaped connecting oil channels.

[0012] Furthermore, each lamination of the motor rotor core is provided with a magnetic slot, and a small magnet and a large magnet are fixedly installed in the magnetic slot. A magnetic slot gap is formed between the magnetic slot and the corresponding small magnet and large magnet. The magnetic slot gap is axially aligned and connected with the corresponding arc-shaped outer cooling oil passage.

[0013] Furthermore, each of the dynamic balancing plates has a spline-shaped mounting hole at its center that matches the motor rotor shaft; each dynamic balancing plate has an inner oil collection groove and an outer oil collection groove that are interconnected, and the inner oil collection groove and the outer oil collection groove are axially aligned and connected to the corresponding magnet groove gaps, and the inner oil collection groove of the dynamic balancing plate has multiple oil outlet holes.

[0014] Furthermore, the first type of oil guide plate lamination, the second type of oil guide plate lamination, the third type of oil guide plate lamination, each motor rotor core lamination of the motor rotor core, and each dynamic balance plate are all provided with multiple lamination weight-removing holes, which are located in the area between adjacent cooling oil channels.

[0015] The present invention discloses a cooling method for an oil-cooled motor rotor cooling structure, the method comprising the following steps:

[0016] S1. Cooling oil enters the central oil passage inside the motor rotor shaft through the cooling oil inlet at the end of the shaft.

[0017] S2. The centrifugal force generated by the rotation of the motor rotor drives the cooling oil to flow radially, and it is thrown out through the oil outlet hole of the motor rotor shaft on the side wall of the motor rotor shaft and enters the cooling oil flow channel of the oil guide plate assembly.

[0018] S3. The cooling oil is split in the multi-path parallel cooling oil flow channel of the oil guide plate assembly, forming a multi-channel parallel flow state, so as to realize the rapid and uniform distribution of oil flow.

[0019] S4. The diverted cooling oil flows axially into the cooling channel of the motor rotor core, flows through the gaps in the magnet slots and directly washes the surface of the small and large magnets, while carrying away the heat generated by the motor rotor core.

[0020] S5. The cooling oil that has completed heat exchange flows axially to both ends of the motor rotor core, collects in the oil collection chamber of the dynamic balance plate, and finally is thrown out of the motor rotor at high speed through the oil outlet of the dynamic balance plate under the action of centrifugal force, and enters the external cooling circuit of the motor.

[0021] Compared with the prior art, the beneficial effects of the present invention are:

[0022] 1. This invention constructs a complete internal cooling oil circuit from the center of the rotor shaft to the inside of the magnet slot and then to the end dynamic balance plate by setting an oil guide plate assembly in the middle of the rotor core. This realizes direct cooling of the rotor magnet and effectively solves the problems of high thermal resistance and low cooling efficiency of traditional indirect cooling methods. It can significantly reduce the working temperature rise of the magnet, avoid irreversible demagnetization of the magnet, and improve the reliability of motor operation.

[0023] 2. The oil guide plate assembly of the present invention adopts multiple oil guide plate stampings axially symmetrically stacked to form a multi-path parallel cooling oil flow channel, which realizes the rapid and uniform distribution of cooling oil and improves the stability and cooling uniformity of the heat exchange process.

[0024] 3. The overall structure of this invention adopts the mature lamination and stacking process in the motor industry, which is highly compatible with existing motor production processes. It does not require major modifications to production equipment. At the same time, the structure is simple and compact, with fewer sealing links, which effectively improves sealing reliability and avoids the problem of cooling medium leakage. Attached Figure Description

[0025] Figure 1 This is an overall axial sectional view of the oil-cooled motor rotor cooling structure of the present invention;

[0026] Figure 2 This is an isometric view of the oil guide plate assembly of the present invention;

[0027] Figure 3 yes Figure 2 The main view;

[0028] Figure 4 This is a schematic diagram of the structure of the third type of oil guide plate punch of the present invention;

[0029] Figure 5 This is a schematic diagram of the structure of the second type of oil guide plate punch of the present invention;

[0030] Figure 6 This is a schematic diagram of the structure of the first type of oil guide plate punch of the present invention;

[0031] Figure 7 This is a schematic diagram of the oil flow direction of the first type of oil guide plate stamping of the present invention;

[0032] Figure 8 This is a schematic diagram of the oil flow direction of the second type of oil guide plate stamping of the present invention;

[0033] Figure 9 This is a schematic diagram of the oil flow direction of the third type of oil guide plate stamping of the present invention;

[0034] Figure 10 This is a schematic diagram of the structure of the motor rotor core lamination of the present invention;

[0035] Figure 11 This is a schematic diagram showing the relationship between the rotor core laminations and magnets of the motor of the present invention;

[0036] Figure 12 This is a schematic diagram of the dynamic balancing plate of the present invention;

[0037] Figure 13 yes Figure 12 Rear view. Detailed Implementation

[0038] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0039] An oil-cooled motor rotor cooling structure includes a motor rotor shaft 6. A motor rotor core 3 and two dynamic balancing plates 5 are fixedly sleeved on the outer side of the motor rotor shaft 6. The two dynamic balancing plates 5 are respectively fixed to both ends of the motor rotor core 3. An oil guide plate assembly 4 is fixed in the middle of the motor rotor core 3. A central oil passage is opened axially inside the motor rotor shaft 6. A cooling oil inlet 7 is provided at the end of the central oil passage. An oil outlet hole 1 of the motor rotor shaft is opened radially on the side wall of the motor rotor shaft 6, which communicates with the internal central oil passage. A cooling oil flow channel is provided on the oil guide plate assembly 4, which communicates with the cooling oil outlet hole 1 of the motor rotor shaft. A cooling channel is provided axially inside the motor rotor core 3, and the inner end of the cooling channel communicates with the cooling oil flow channel of the oil guide plate assembly 4. The outer end of the cooling channel is respectively connected to the oil collection chamber of the two dynamic balancing plates 5.

[0040] The oil outlet hole 1 of the motor rotor shaft, the cooling oil flow channel of the oil guide plate assembly 4, the cooling channel of the motor rotor core 3, the oil collection chamber and the oil outlet hole of the dynamic balance plate 5 are connected in sequence to form a complete cooling oil circuit that is bidirectionally connected in the axial and radial directions.

[0041] Furthermore, the oil guide plate assembly 4 includes multiple axially symmetrical oil guide plate stamps. Each oil guide plate stamp has an independent cooling oil channel, and after being combined and stacked, they form a multi-path parallel cooling oil flow channel. Through the mechanical structure of the oil guide plate assembly 4, it has a complex cooling oil path, which increases the flow path of the cooling oil and the residence time inside the motor rotor when the cooling oil flows through the oil guide plate assembly 4, thereby carrying away more heat.

[0042] Furthermore, the multiple oil guide plate stamps include at least a first type oil guide plate stamp 9, a second type oil guide plate stamp 13, and a third type oil guide plate stamp 16; the oil guide plate stamps are not limited to using more or fewer other types of stamps, the third type oil guide plate stamp 16 is disposed in the middle, and the second type oil guide plate stamp 13 and the first type oil guide plate stamp 9 are symmetrically stacked on both sides of its axial direction.

[0043] Furthermore, the third type of oil guide plate stamp 16 is a circular silicon steel sheet stamp with a centrally symmetrical structure. The center of the third type of oil guide plate stamp 16 is provided with a spline-shaped mounting hole that matches the motor rotor shaft 6. N sets of third type of oil guide plate inlet channels 8, N sets of wave-shaped bidirectional diversion channels 17 and N sets of arc-shaped bidirectional diversion channels 38 are evenly distributed along the circumference of the third type of oil guide plate stamp 16. The N sets of wave-shaped bidirectional diversion channels 17 and N sets of arc-shaped bidirectional diversion channels 38 are alternately arranged. The oil inlet of each set of third type of oil guide plate inlet channels 8 is connected to the corresponding motor rotor shaft oil outlet hole 1.

[0044] Furthermore, the second type of oil guide plate stamp 13 is a circular silicon steel sheet stamp with an overall centrally symmetrical structure. The center of the second type of oil guide plate stamp 13 is provided with a spline-shaped mounting hole that matches the motor rotor shaft 6. N sets of radial transition oil channels 15 and 2N sets of arc-shaped connecting oil channels 14 are evenly distributed along the circumference of the second type of oil guide plate stamp 13. Each set of radial transition oil channels 15 is axially aligned and connected with the corresponding third type of oil guide plate oil inlet channel 8. Each set of arc-shaped connecting oil channels 14 is axially aligned and connected with the corresponding wave-shaped bidirectional diversion oil channel 17 and arc-shaped bidirectional diversion oil channel 38.

[0045] Furthermore, the first type of oil guide plate stamp 9 is a circular silicon steel sheet stamp with an overall centrally symmetrical structure. The first type of oil guide plate stamp 9 has a spline-shaped mounting hole in the center that matches the motor rotor shaft 6. N sets of Y-shaped oil inlet channels 11 and 2N sets of arc-shaped outer cooling oil channels 10 are evenly distributed along the circumference of the first type of oil guide plate stamp 9. The main part 18 of each set of Y-shaped oil inlet channels 11 is axially aligned and connected with the corresponding radial transition oil channel 15. The two branches 19 of each set of Y-shaped oil inlet channels 11 and each set of arc-shaped outer cooling oil channels 10 are axially aligned and connected with the corresponding arc-shaped connecting oil channel 14.

[0046] Furthermore, the motor rotor core 3 comprises multiple axially stacked motor rotor core laminations. The overall stack length of the motor core is divided into 6 segments, which can be designed into different integer segments according to the increase or decrease of the stack length to meet actual usage requirements. Each motor rotor core lamination of the motor rotor core 3 has a magnetic slot, in which small magnets 28 and large magnets 29 are fixedly installed. A magnetic slot gap is formed between the magnetic slot and the corresponding small magnets 28 and large magnets 29. The magnetic slot gaps are axially aligned and connected to the corresponding arc-shaped outer cooling oil passages 10.

[0047] The gap in the magnet slot includes an injection groove 25 and a magnet slot cooling oil channel 27. The magnet slot cooling oil channel 27 is arranged close to the small magnet 28 and the large magnet 29 to achieve direct cooling of the magnet.

[0048] The gap of the rotor magnet slot can be adjusted appropriately according to the strength requirements of the motor. In other words, the glue injection groove 25 of the rotor magnet slot can also be used as a cooling oil passage.

[0049] Furthermore, each of the dynamic balancing plates 5 is a circular plate, and each dynamic balancing plate 5 has a spline-shaped mounting hole at its center that matches the motor rotor shaft 6; each dynamic balancing plate 5 has an inner oil collecting groove 33 and an outer oil collecting groove 34 that are interconnected, and the inner oil collecting groove 33 and the outer oil collecting groove 34 are respectively axially aligned and connected with the corresponding magnet slot gaps, and the inner oil collecting groove 33 of the dynamic balancing plate has a plurality of dynamic balancing plate oil outlet holes 2.

[0050] The number of oil outlet holes 2 on the dynamic balance plate can be adjusted according to the actual cooling requirements of the motor to maximize the optimization of the motor cooling solution.

[0051] Furthermore, multiple triangular de-weighting holes 12 are evenly distributed on each of the first type of oil guide plate lamination 9, the second type of oil guide plate lamination 13, the third type of oil guide plate lamination 16, each motor rotor core lamination of the motor rotor core 3, and each dynamic balance plate 5. This balances the requirements for motor rotor dynamic balance and lightweight design, while also allowing communication with oil channels to facilitate the flow of cooling oil and achieve cooling of the motor core. The de-weighting holes 12 are located in the area between adjacent cooling oil channels and are staggered with each cooling oil channel to avoid oil path interference and ensure smooth oil flow.

[0052] The present invention discloses a cooling method for an oil-cooled motor rotor cooling structure, the method comprising the following steps:

[0053] S1. Cooling oil enters the central oil passage inside the motor rotor shaft 6 through the cooling oil inlet 7 at the end of the rotor shaft 6.

[0054] S2. The centrifugal force generated by the rotation of the motor rotor drives the cooling oil to flow radially, and it is thrown out through the motor rotor shaft oil outlet 1 on the side wall of the motor rotor shaft 6 and enters the cooling oil flow channel of the oil guide plate assembly 4.

[0055] S3. Cooling oil is split into multiple parallel cooling oil channels in the oil guide plate assembly 4, forming a multi-channel parallel flow state to achieve rapid and uniform distribution of oil flow.

[0056] 301. Cooling oil enters the oil inlet channel 8 of the third type oil guide plate punch 16;

[0057] 302. The cooling oil entering the oil inlet channel 8 of the third type of oil guide plate flows axially into the radial transition oil channel 15 of the second type of oil guide plate stamp 13, and then flows axially into the main part 18 of the Y-shaped oil inlet channel 11 of the first type of oil guide plate stamp 9, and splits into two paths at the end of the main part 18, flowing into the two branches 19 of the Y-shaped oil inlet channel 11 respectively.

[0058] 303. The cooling oil entering the two branches 19 flows axially into the corresponding arc-shaped connecting oil passage 14;

[0059] 304. The cooling oil entering the arc-shaped connecting oil passage 14 flows axially into the corresponding arc-shaped bidirectional split oil passage 38, wave-shaped bidirectional split oil passage 17 and arc-shaped outer cooling oil passage 10.

[0060] 305. At the same time, the cooling oil entering the wave-shaped bidirectional split oil passage 17 flows axially into the remaining arc-shaped connecting oil passage 14.

[0061] 306. The cooling oil entering the remaining arc-shaped connecting oil passage 14 flows axially into the remaining arc-shaped outer cooling oil passage 10, forming a multi-channel parallel flow state. The flow fills the entire oil guide plate assembly, realizing rapid and uniform distribution of oil flow.

[0062] S4. The diverted cooling oil flows axially into the cooling channel of the motor rotor core 3, flows through the gaps in the magnet slots and directly washes the surfaces of the small magnet 28 and the large magnet 29, while carrying away the heat generated by the motor rotor core 3.

[0063] S5. The cooling oil that has completed heat exchange flows axially to both ends of the motor rotor core 3 and collects in the oil collection chamber of the dynamic balance plate 5, namely the inner oil collection groove 33 and the outer oil collection groove 34 of the dynamic balance plate. Finally, it is thrown out of the motor rotor at high speed through the oil outlet hole 2 of the dynamic balance plate under the action of centrifugal force and enters the external cooling circuit of the motor to complete a complete cooling cycle.

[0064] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of the equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0065] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A cooling structure for an oil-cooled motor rotor, comprising a motor rotor shaft (6), wherein a motor rotor core (3) and two dynamic balancing plates (5) are fixedly sleeved on the outer side of the motor rotor shaft (6), and the two dynamic balancing plates (5) are respectively fixed to both ends of the motor rotor core (3); characterized in that: The motor rotor core (3) is fixed with an oil guide plate assembly (4) in the middle. The motor rotor shaft (6) has a central oil passage along the axial direction. The end of the central oil passage is provided with a cooling oil inlet (7). The side wall of the motor rotor shaft (6) has a motor rotor shaft oil outlet hole (1) that communicates with the internal central oil passage. The oil guide plate assembly (4) has a cooling oil flow channel that communicates with the motor rotor shaft oil outlet hole (1). The motor rotor core (3) has a cooling channel that is axially connected and whose inner end is connected with the cooling oil flow channel of the oil guide plate assembly (4). The outer end of the cooling channel is connected to the oil collection chamber of the two dynamic balance plates (5).

2. The oil-cooled motor rotor cooling structure according to claim 1, characterized in that: The oil guide plate assembly (4) includes multiple axially symmetrical oil guide plate stamps. Each oil guide plate stamp has an independent cooling oil channel, and after being stacked together, they form a multi-path parallel cooling oil flow channel.

3. The oil-cooled motor rotor cooling structure according to claim 2, characterized in that: The multiple oil guide plate stamps include at least a first type oil guide plate stamp (9), a second type oil guide plate stamp (13), and a third type oil guide plate stamp (16); the third type oil guide plate stamp (16) is located in the middle, and the second type oil guide plate stamp (13) and the first type oil guide plate stamp (9) are symmetrically stacked on both sides of its axial direction.

4. The oil-cooled motor rotor cooling structure according to claim 3, characterized in that: The third type of oil guide plate punch (16) has a spline-shaped mounting hole in the center that matches the motor rotor shaft (6); the third type of oil guide plate punch (16) has N sets of third type of oil guide plate inlet oil channels (8), N sets of wave-shaped bidirectional diversion oil channels (17) and N sets of arc-shaped bidirectional diversion oil channels (38) distributed along the circumferential direction. The N sets of wave-shaped bidirectional diversion oil channels (17) and N sets of arc-shaped bidirectional diversion oil channels (38) are arranged alternately. The oil inlet of each set of the third type of oil guide plate inlet oil channels (8) is connected to the corresponding motor rotor shaft oil outlet hole (1).

5. The oil-cooled motor rotor cooling structure according to claim 4, characterized in that: The second type of oil guide plate stamp (13) has a spline-shaped mounting hole in the center that matches the motor rotor shaft (6); the second type of oil guide plate stamp (13) has N sets of radial transition oil channels (15) and 2N sets of arc-shaped connecting oil channels (14) distributed along the circumferential direction. Each set of radial transition oil channels (15) is axially aligned and connected with the corresponding third type of oil guide plate oil inlet channel (8), and each set of arc-shaped connecting oil channels (14) is axially aligned and connected with the corresponding wave-shaped bidirectional diversion oil channel (17) and arc-shaped bidirectional diversion oil channel (38).

6. The oil-cooled motor rotor cooling structure according to claim 5, characterized in that: The first type of oil guide plate stamp (9) has a spline-shaped mounting hole in the center that matches the motor rotor shaft (6); the first type of oil guide plate stamp (9) has N sets of Y-shaped oil inlet channels (11) and 2N sets of arc-shaped outer cooling oil channels (10) distributed along the circumferential direction; the main part (18) of each set of Y-shaped oil inlet channels (11) is axially aligned and connected with the corresponding radial transition oil channel (15); the two branches (19) of each set of Y-shaped oil inlet channels (11) and each set of arc-shaped outer cooling oil channels (10) are axially aligned and connected with the corresponding arc-shaped connecting oil channel (14).

7. The oil-cooled motor rotor cooling structure according to claim 6, characterized in that: Each lamination of the motor rotor core (3) is provided with a magnetic slot. Small magnets (28) and large magnets (29) are fixedly installed in the magnetic slots. A magnetic slot gap is formed between the magnetic slot and the corresponding small magnets (28) and large magnets (29). The magnetic slot gap is axially aligned and connected with the corresponding arc-shaped outer cooling oil passage (10).

8. The oil-cooled motor rotor cooling structure according to claim 7, characterized in that: Each of the dynamic balancing plates (5) has a spline-shaped mounting hole at its center that matches the motor rotor shaft (6); each of the dynamic balancing plates (5) has an internal oil collection groove (33) and an external oil collection groove (34) that are interconnected. The internal oil collection groove (33) and the external oil collection groove (34) are axially aligned and connected with the corresponding magnetic steel groove gaps, respectively. The internal oil collection groove (33) of the dynamic balancing plate has multiple oil outlet holes (2).

9. The oil-cooled motor rotor cooling structure according to claim 8, characterized in that: The first type of oil guide plate lamination (9), the second type of oil guide plate lamination (13), the third type of oil guide plate lamination (16), the motor rotor core lamination of the motor rotor core (3), and each dynamic balance plate (5) are provided with multiple lamination weight removal holes (12), which are located in the area between adjacent cooling oil channels.

10. A cooling method for the oil-cooled motor rotor cooling structure according to claim 1, characterized in that: The method includes the following steps: S1. Cooling oil enters the central oil passage inside the motor rotor shaft (6) through the cooling oil inlet (7) at the end of the rotor shaft (6); S2. The centrifugal force generated by the rotation of the motor rotor drives the cooling oil to flow radially, and it is thrown out through the oil outlet hole (1) of the motor rotor shaft (6) on the side wall of the motor rotor shaft (6) and enters the cooling oil flow channel of the oil guide plate assembly (4). S3. The cooling oil is split in the multi-path parallel cooling oil flow channel of the oil guide plate assembly (4) to form a multi-channel parallel flow state, so as to realize the rapid and uniform distribution of oil flow. S4. The cooling oil after diversion flows axially into the cooling channel of the motor rotor core (3), flows through the gap of the magnet slot and directly washes the surface of the small magnet (28) and the large magnet (29), while carrying away the heat generated by the motor rotor core (3). S5. The cooling oil that has completed heat exchange flows axially to both ends of the motor rotor core (3), gathers in the oil collection chamber of the dynamic balance plate (5), and finally is thrown out of the motor rotor at high speed through the oil outlet hole (2) of the dynamic balance plate under the action of centrifugal force, and enters the external cooling circuit of the motor.

Images