CN217590416U - Motor rotor structure - Google Patents

Abstract

The utility model provides a motor rotor structure, which belongs to the field of electric automobiles, and comprises a rotor body and at least one pair of magnets which are axially arranged and are communicated with the inside of the rotor body; the two ends of the rotor body are correspondingly provided with cooling cavities which can cover all or part of end faces of the rotor body and the magnets; the rotor body is provided with a pore passage for communicating a pair of cooling cavities distributed at two ends of the magnet; wherein, a liquid inlet hole capable of feeding liquid is arranged on one cooling cavity, and a liquid outlet hole capable of discharging liquid is arranged on the other cooling cavity. The motor rotor structure in this scheme can effectively reduce the overheated demagnetization of magnet and lead to the risk that motor performance reduces, need not to increase the volume of stator and rotor in addition and holds more heats, also need not to select the high magnet of temperature resistant grade to can effectively promote motor power density, reduce motor cost.

Description

Motor rotor structure

Technical Field

The utility model belongs to the technical field of electric automobile and specifically relates to an electric motor rotor structure is related to.

Background

The motor consists of a rotor and a stator and is a device for realizing mutual conversion between electric energy and mechanical energy and between mechanical energy and electric energy. The rotor of the motor is a rotating part in the motor, and the rotor of the brushless direct current motor is formed by embedding permanent magnets (such as magnets) with a certain number of pole pairs on the surface of an iron core or in the iron core, wherein the permanent magnets are mainly used for establishing an enough magnetic field in an air gap of the motor.

Pure electric vehicles driving motor rotor who uses in the current market can't directly cool off in the work, needs to increase the volume of stator and rotor and holds more heats, perhaps selects the magnet that the temperature resistant grade is high to reduce the overheated demagnetization of magnet and lead to the risk that motor performance reduces, but in above-mentioned two kinds of schemes, the volume that increases stator and rotor is unfavorable for promoting driving motor power density, uses the magnet that the temperature resistant grade is high to realize increasing driving motor's cost.

In view of this, the present invention is especially provided.

SUMMERY OF THE UTILITY MODEL

The utility model provides an electric motor rotor structure to solve among the prior art because of adopting the volume that increases stator and rotor or select the temperature resistant magnet to reduce the overheated demagnetization of magnet, and lead to reducing driving motor power density or the problem that increases driving motor cost.

In order to solve the above problem, the utility model adopts the following scheme:

a motor rotor structure comprises a rotor body, and at least one pair of magnets axially arranged in the rotor body;

the two ends of the rotor body are correspondingly provided with cooling cavities which can cover all or part of end faces of the rotor body and the magnet; the rotor body is provided with a pore passage which is used for communicating the pair of cooling cavities distributed at the two ends of the magnet; one cooling cavity is provided with a liquid inlet hole capable of feeding liquid, and the other cooling cavity is provided with a liquid outlet hole capable of discharging liquid.

The motor rotor structure in the scheme comprises a rotor body and at least one pair of magnets axially arranged in the rotor body; the two ends of the rotor body are correspondingly provided with cooling cavities which can cover all or part of the end surfaces of the rotor body and the magnets, and the cooling cavities can cool the rotor body and the magnets which are in contact with the cooling cavities; the rotor body is provided with a pore passage for communicating a pair of cooling cavities distributed at two ends of the magnet;

one cooling cavity is provided with a liquid inlet hole capable of feeding liquid, the other cooling cavity is provided with a liquid outlet hole capable of discharging liquid, and a pair of cooling cavities and the pore channel form a passage, so that cooling oil in an oil way can flow conveniently, heat can be taken away in time, the risk of motor performance reduction caused by magnet overheating demagnetization can be effectively reduced, and the motor reliability is improved; the cooling cavity filled with cooling oil is in direct contact cooling with the rotor body and the magnet, so that more heat is contained without increasing the volume of the stator and the rotor, and the magnet with high temperature resistance level is not required to be selected, so that the power density of the motor can be effectively improved, and the cost of the motor is reduced.

In other preferable schemes, the rotor further comprises a hollow shaft axially penetrating the middle part of the rotor body; the side port communicated with the cooling cavity is formed in the side wall of the hollow shaft, a cavity capable of containing cooling oil is formed in the hollow shaft, and the cooling oil in the hollow shaft can enter the cooling cavity through the side port.

In other preferable schemes, a plurality of pairs of the magnets are annularly arranged on the outer side of the hollow shaft; and in the direction towards the hollow shaft, the distance between each pair of magnets is gradually reduced, so that the magnets are conveniently arranged, and the magnets are radially arranged outwards by taking the hollow shaft as the center in the rotor body.

In other preferred schemes, a pair of cooling cavities are correspondingly arranged at two ends of each pair of magnets in a laminating manner; each pair of cooling cavities comprises a first cooling cavity arranged at one end of the magnet and a second cooling cavity arranged at the other end of the magnet, the two ends of the magnet are respectively contacted with the first cooling cavity and the second cooling cavity, and the first cooling cavity and the second cooling cavity are both flat, so that the magnet and the rotor body can be fully contacted, and the heat absorption effect is improved;

the side wall of the hollow shaft is provided with at least one side port which is in one-to-one correspondence with the first cooling cavity, cooling oil in the hollow shaft can enter the first cooling cavity through the side port, then flows into the second cooling cavity through the pore channel, and is discharged from a liquid outlet hole formed in the second cooling cavity, so that the circulating cooling effect is realized.

The quantity of side openings formed in the side wall of the hollow shaft is the same as that of the first cooling cavities, the side openings are communicated in a one-to-one correspondence mode, and the hollow shaft can continuously supply cooling oil to the first cooling cavities.

In other preferred schemes, a liquid inlet groove is connected between the first cooling cavity and the side port in a through manner, and cooling oil in the hollow shaft can enter the liquid inlet groove through the side port and then flow into the first cooling cavity; set up the liquid hole with external intercommunication on the second cooling chamber, go out the liquid hole and can in time discharge rotor body with the coolant oil that carries the heat, the circulation of being convenient for is endothermic, promotes the cooling effect.

In other preferred schemes, the rotor further comprises a pair of end plates arranged at two ends of the rotor body; the first cooling cavity is formed in one end plate, the second cooling cavity is formed in the other end plate, and the end plates can play a role in guaranteeing normal work of the first cooling cavity and the second cooling cavity.

In other preferred schemes, at least two first cooling cavities and at least two second cooling cavities are alternately arranged on the inner side of each end plate;

the first cooling cavity on the inner side of one end plate is correspondingly communicated with the second cooling cavity on the inner side of the other end plate, and the flowing directions of cooling oil in two adjacent pore channels are opposite, so that the cooling effect is better realized.

In other preferred schemes, the rotor body and the hollow shaft are both cylindrical structures, the diameter of the rotor body is 3-4 times of that of the hollow shaft, and enough cooling liquid can be contained in the hollow shaft.

In other preferred schemes, the duct is a flat cavity column structure and is located between two ends of each pair of magnets which are far away from each other, and the flat cavity can make the contact surface with the inside of the iron core larger, so that the contact cooling is facilitated.

In other preferred schemes, the cooling cavity is a cavity structure enclosed by the end plate and the end part of the rotor body, no additional sealing device is needed, and the cooling cavity can be directly communicated with the pore channel.

Compared with the prior art, the utility model discloses following beneficial effect has:

the application provides a motor rotor structure, which comprises a rotor body and a magnet; the two ends of the magnet are correspondingly provided with a pair of cooling cavities in an attaching manner, the rotor body is also internally provided with a pore passage which can be communicated with the cooling cavities at the two ends, one cooling cavity is provided with a liquid inlet hole which can feed liquid, the other cooling cavity is provided with a liquid outlet hole which can discharge liquid, the pair of cooling cavities and the pore passage form a passage, so that cooling oil in an oil passage can flow conveniently, heat can be taken away in time, the risk of motor performance reduction caused by magnet overheating and demagnetization can be effectively reduced, and the motor reliability is improved; the cooling chamber that is equipped with the cooling oil cools off with rotor body and magnet direct contact, and first cooling chamber and second cooling chamber are the platykurtic, can guarantee with magnet and rotor body abundant contact, promote the heat absorption effect to need not to increase the volume of stator and rotor and hold more heats, also need not to select the high magnet of temperature resistant grade, thereby can effectively promote motor power density, reduce motor cost.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the technical solutions in the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a cross-sectional view of one particular electric machine rotor construction described herein;

FIG. 2 is a view of one end of one particular electric machine rotor structure described herein;

fig. 3 is a view of another end of a particular motor rotor structure according to the present application.

In the above figures, the list of parts represented by the various reference numerals is as follows:

a rotor body-100; a magnet-200; a cooling chamber-300; a first cooling chamber-301; a second cooling chamber-302; a liquid inlet tank-303; a liquid outlet hole-304; a bore-400; a hollow shaft-500; a side port-501; an end plate-600.

Detailed Description

In order to make the above and other features and advantages of the present invention more apparent, the present invention will be further described with reference to the accompanying drawings. It is understood that the specific embodiments described herein are for purposes of illustration only and are not intended to be limiting, as those of ordinary skill in the art will recognize.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and for simplicity of description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," and "fixed" are to be construed broadly and may, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

In the present application, unless expressly stated or limited otherwise, the first feature may be directly on or directly under the second feature or indirectly via intermediate members. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Referring to fig. 1-3, an embodiment of a rotor structure of an electric machine according to the present invention is shown;

the motor rotor structure provided by the embodiment comprises a rotor body 100, and at least one pair of magnets 200 axially arranged inside the rotor body 100;

the two ends of the rotor body 100 are correspondingly provided with cooling cavities 300 capable of covering all or part of end faces of the rotor body 100 and the magnet 200, and the cooling cavities 300 can cool the rotor body 100 and the magnet 200 which are in contact with the cooling cavities; the rotor body 100 is provided with a duct 400 communicating a pair of cooling cavities 300 distributed at both ends of the magnet 200; one cooling chamber 300 is provided with a liquid inlet hole for liquid inlet, and the other cooling chamber 300 is provided with a liquid outlet hole 304 for liquid discharge.

The motor rotor structure in the scheme comprises a rotor body 100 and at least one pair of magnets 200 axially arranged inside the rotor body 100; the two ends of each pair of magnets 200 are correspondingly provided with a pair of cooling cavities 300 in an attaching mode, a pore channel 400 for communicating the pair of cooling cavities 300 at the two ends of each pair of magnets 200 is further arranged between the magnets 200, the pore channel 400 is equivalent to a pipeline for communicating the two cooling cavities 300, a liquid inlet hole capable of feeding liquid is formed in one cooling cavity 300, the liquid inlet hole is communicated with an external oil storage device and can continuously provide cooling oil or cooling liquid for the cooling cavities 300, a liquid outlet hole 304 capable of discharging liquid is formed in the other cooling cavity 300, the cooling oil absorbing heat can be heated and needs to be discharged in time, so that the low-temperature cooling oil can normally circulate, a passage is formed by the communication of the pore channel 400 for the cooling oil in an oil circuit to flow, the low-temperature cooling oil enters the cooling cavity 300 at one end through the liquid inlet hole and flows into the cooling cavity 300 at the other end through the pore channel 400, the cooling cavity 300 is attached to contact with the two end portions of the magnets 200 and a rotor body to absorb heat, the cooling oil after the heat is discharged from the liquid outlet hole 304, the heat is discharged out of the system in time, the system, the overheat of the magnets 200 can be effectively reduced, and the risk of demagnetization of the motor can be reduced; the cooling cavity 300 filled with the cooling oil is in direct contact with the rotor body 100 and the magnet 200 for cooling, so that the volume of the stator and the rotor does not need to be increased to contain more heat, the magnet 200 with high temperature resistance level does not need to be selected, the power density of the motor can be effectively improved, and the cost of the motor is reduced.

In other embodiments, a pair of magnets 200 are distributed as shown in fig. 2, two magnetic steel sheets arranged in parallel are used as one magnet 200 in the present scheme, that is, the pair of magnets 200 includes four magnetic steel sheets, the number of pairs of magnets 200 is the number of poles of the motor rotor, the number of cooling cavities 300 arranged at each end is the same as the number of poles of the motor rotor, and both the number of poles of the motor rotor and the number of cooling cavities 300 at each end in fig. 2 are 4.

Further, the rotor comprises a hollow shaft 500 axially penetrating the middle part of the rotor body 100, the hollow shaft 500 is a hollow cylindrical tubular structure, two ends of the hollow shaft 500 penetrate through two ends of the rotor body 100, and cooling oil or cooling liquid is contained in the hollow shaft 500; the side mouth 501 that communicates with cooling chamber 300 is seted up to hollow shaft 500's lateral wall, hollow shaft 500's inside is for the cavity that can hold the cooling oil, cooling oil in hollow shaft 500 can get into in cooling chamber 300 via side mouth 501, magnet 200 and the cooling chamber 300 outer wall contact cooling, cooling chamber 300 is the platykurtic structure, its specific shape can be adjusted according to magnet 200's position, only need guarantee that the outer wall of cooling chamber 300 can hug closely the tip of magnet 200 can, can effectively cool off.

The side port 501 in this scheme is a radial circular through hole, one end of the circular through hole is communicated with the inner cavity of the hollow shaft 500, the other end is communicated with the liquid inlet groove, cooling oil (liquid) is introduced into the inner cavity of the hollow shaft 500 through an oil pipe on an end cover (or a similar structure, the structures are not embodied in the figure of the patent) of the hollow shaft 500, and continuous oil supply is realized by using an oil pump (not embodied in the figure of the patent).

Further, a plurality of pairs of magnets 200 are annularly arranged on the outer side of the hollow shaft 500; and the distance between each pair of magnets 200 is gradually reduced in the direction toward the hollow shaft 500, so that the magnets 200 are conveniently arranged, i.e. the plurality of pairs of magnets 200 are symmetrically and radially arranged outwards by taking the hollow shaft 500 as the center.

In this embodiment, a plurality of pairs of magnets 200 are symmetrically arranged in a radial manner, and the cooling cavities 300 at both ends are also arranged in an arc shape corresponding to the shape of the magnets 200, so that the cooling cavities 300 can be in full contact with both ends of the magnets 200.

Further, a pair of cooling cavities 300 is correspondingly attached to two ends of each pair of magnets 200; each pair of cooling cavities 300 comprises a first cooling cavity 301 arranged at one end of the magnet 200 and a second cooling cavity 302 arranged at the other end of the magnet 200, and the first cooling cavity 301 and the second cooling cavity 302 at the corresponding positions are communicated through the duct 400; at least one side port 501 corresponding to the first cooling cavity 301 one by one is formed in the side wall of the hollow shaft 500, and cooling oil in the hollow shaft 500 can enter the first cooling cavity 301 through the side port 501, then flow into the second cooling cavity 302 through the hole channel 400, and flow out of the system through the liquid outlet hole 304, so that absorbed heat can be brought out of the motor rotor in time.

The first cooling cavity 301 and the second cooling cavity 302 have the same shape, and the difference is that the first cooling cavity 301 is provided with a liquid inlet hole, the second cooling cavity 302 is provided with a liquid outlet hole 304, and cooling liquid (oil) enters the first cooling cavity 301 from the liquid inlet hole, sequentially flows through the duct 400 and the second cooling cavity 302, and then flows out from the liquid outlet hole 304 on the second cooling cavity 302.

Further, a liquid inlet groove is connected between the first cooling cavity 301 and the side port 501 in a through manner, the liquid inlet groove is a pipeline for communicating the first cooling cavity 301 with the side port 501, the side wall of the hollow shaft 500 is provided with a plurality of side ports 501 with the number and the positions consistent with those of the first cooling cavity 301, and cooling oil in the hollow shaft 500 can respectively enter the corresponding liquid inlet grooves through the side ports 501 and then flow into the first cooling cavity 301; the second cooling cavity 302 is provided with a liquid outlet 304 communicated with the outside, and the liquid outlet 304 can discharge cooling oil carrying heat out of the rotor body 100 in time, so that heat absorption is facilitated, and the cooling effect is improved.

Further, a pair of end plates 600 disposed at both ends of the rotor body 100; first cooling chamber 301 and second cooling chamber 302 all are in between end plate 600 and rotor body 100, and end plate 600 can play the effect of guaranteeing first cooling chamber 301 and the normal work of second cooling chamber 302, and rotor end plate 600's form is circular, and two whole covers at the both ends of rotor body 100 of end plate 600, and the recess column structure has been seted up to end plate 600's inboard, can form first cooling chamber 301 and second cooling chamber 302 between its and two tip of rotor body 100.

Further, at least two first cooling cavities 301 and at least two second cooling cavities 302 are alternately arranged on the inner side of each end plate 600, as shown in fig. 3, two first cooling cavities 301 and two second cooling cavities 302 are alternately arranged on the inner side of each end plate 600, and the whole body resembles a four-blade petal shape; the first cooling cavity 301 on the inner side of one end plate 600 is correspondingly communicated with the second cooling cavity 302 on the inner side of the other end plate 600, so that heat dissipation is facilitated.

In another preferred embodiment, the two end rotor end plates 600 are mounted on the two ends of the rotor body with the angles of one pole (i.e. one cooling cavity 300) twisted in the circumferential direction opposite to each other to ensure that the first cooling cavity 301 and the second cooling cavity 302 are opposite to each other.

Further, the rotor body 100 and the hollow shaft 500 are both cylindrical structures, and the diameter of the rotor body 100 is 3 to 4 times of the diameter of the hollow shaft 500. In other embodiments, other proportional relationships between the diameter of rotor body 100 and the diameter of hollow shaft 500 are possible.

Further, the duct 400 is a flat hollow cylindrical structure and is located between two ends of each pair of magnets 200, which are far away from each other, so as to guide the oil in the first cooling chamber 301 into the second cooling chamber 302 in time.

Further, the cooling cavity 300 is a cavity structure formed by the end plate 600 and the end portion of the rotor body 100, and the cavity structure is provided with a hole as a liquid inlet hole, so that an additional structure is not required, and the cost is low. In another embodiment, in order to improve the overall tightness of the system, the first cooling cavity 301 and the second cooling cavity 302 may also be provided as independent sealed cavity devices, the inner sides of the two rotor end plates 600 are provided with grooves, the first cooling cavity 301 and the second cooling cavity 302 are installed in the grooves, the first cooling cavity 301 and the second cooling cavity 302 are respectively provided with two holes, one hole is used for communicating with the liquid inlet groove 303, and the other hole is used for communicating with the duct 400.

Referring to fig. 1-3, in a preferred embodiment, the hollow shaft 500 and the rotor body 100 are both cylindrical structures, the hollow shaft 500 is a hollow cavity structure, and both ends of the hollow shaft 500 penetrate through both ends of the rotor body 100, the hollow shaft 500 is communicated with the first cooling cavity 301 through the liquid inlet slot 303, the distance between the second cooling cavity 302 and the hollow shaft 500 is the same as the length of the liquid inlet slot 303, a hole plug is detachably installed on the liquid outlet hole 304 in a matched manner, when the motor rotor works, the cooling oil in the hollow shaft 500 can firstly enter the first cooling cavity 301, then flow into the second cooling cavity 302 through the hole 400, and finally be discharged from the liquid outlet hole 304, the first cooling cavity 301 and the second cooling cavity 302 are both flat arc-shaped cavities, which can be tightly attached to the end of the magnet 200, the rotor body 100 and the magnet 200 can be cooled in contact with the first cooling cavity 301 and the second cooling cavity 302 at both ends, the oil after absorbing heat can be timely discharged from the liquid outlet hole 304, so as to continuously absorb heat, while improving the motor efficiency and NVH performance, directly cooling the rotor body 100 and reducing the magnet 200, thereby reducing the risk of overheating and reducing the demagnetization risk of the motor.

Referring to fig. 1-3, in another preferred embodiment, the hollow shaft 500 and the rotor body 100 are both cylindrical structures, the diameter of the rotor body 100 is 3 times of the diameter of the hollow shaft 500, the hollow shaft 500 is communicated with the first cooling cavity 301 through the liquid inlet slot 303, the thickness of the end plate 600 is slightly greater than the thickness of the first cooling cavity 301 and the second cooling cavity 302, when the motor rotor works, the cooling oil in the hollow shaft 500 can firstly enter the first cooling cavity 301, then flow into the second cooling cavity 302 through the oblate duct 400, the duct 400 is close to the edge of the rotor body 100 and finally is discharged from the liquid outlet hole 304, the rotor body 100 and the magnet 200 (in this embodiment, the magnet 200 is a magnetic steel sheet) can contact with the first cooling cavity 301 and the second cooling cavity 302 at both ends for cooling, the oil after absorbing heat can be timely discharged from the liquid outlet hole 304, so as to facilitate continuous heat absorption, and directly cool the rotor body 100 and the magnet 200 while improving the motor efficiency and NVH performance, thereby reducing the risk of overheating of the motor 200 and reducing the demagnetization risk of the motor.

The application provides an electric motor rotor structure, including rotor body 100 and magnet 200, the cooling chamber 300 that is equipped with the coolant oil cools off with rotor body 100 and magnet 200 direct contact to the volume that need not to increase stator rotor holds more heats, also need not to select the high magnet 200 of temperature resistant grade, thereby can effectively promote motor power density, reduces motor cost.

Although embodiments of the present invention have been shown and described, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention, and that variations, modifications, substitutions and alterations can be made to the above embodiments by those of ordinary skill in the art without departing from the scope of the present invention.

Claims (10)

1. The motor rotor structure is characterized by comprising a rotor body (100) and at least one pair of magnets (200) which are axially arranged in the rotor body (100) in a penetrating way;

the two ends of the rotor body (100) are correspondingly provided with cooling cavities (300) which can cover all or part of end faces of the rotor body (100) and the magnets (200);

the rotor body (100) is provided with a pore canal (400) for communicating the pair of cooling cavities (300) distributed at the two ends of the magnet (200);

one cooling cavity is provided with a liquid inlet hole capable of feeding liquid, and the other cooling cavity is provided with a liquid outlet hole (304) capable of discharging liquid.

2. The electric machine rotor structure according to claim 1, further comprising a hollow shaft (500) axially penetrating the middle of the rotor body (100); the side wall of the hollow shaft (500) is provided with a side port (501) communicated with the liquid inlet hole.

3. The electric machine rotor structure according to claim 2, characterized in that a plurality of pairs of magnets (200) are arranged around the outside of the hollow shaft (500); and the spacing between each pair of magnets (200) is tapered in a direction towards the hollow shaft (500).

4. The electric machine rotor structure according to claim 3, characterized in that a pair of cooling cavities (300) are correspondingly arranged at both ends of each pair of magnets (200);

each pair of cooling cavities (300) comprises a first cooling cavity (301) arranged at one end of the magnet (200) and a second cooling cavity (302) arranged at the other end of the magnet (200);

the side wall of the hollow shaft (500) is provided with at least one side port (501) corresponding to the first cooling cavity (301) in a one-to-one mode.

5. The electric machine rotor structure according to claim 4, characterized in that a liquid inlet groove (303) is connected between the first cooling cavity (301) and the side port (501); the second cooling cavity (302) is provided with the liquid outlet hole (304).

6. The electric machine rotor structure of claim 4, further comprising a pair of end plates (600) disposed at both ends of the rotor body (100); the first cooling cavity (301) is formed in one end plate, and the second cooling cavity (302) is formed in the other end plate.

7. The electric machine rotor structure according to claim 6, characterized in that the inner side of each end plate (600) is provided with at least two first cooling cavities (301) and at least two second cooling cavities (302) alternately;

wherein the first cooling cavity (301) on the inner side of one end plate (600) is correspondingly communicated with the second cooling cavity (302) on the inner side of the other end plate (600).

8. The electric machine rotor structure according to claim 7, characterized in that the rotor body (100) and the hollow shaft (500) are both cylindrical structures, and the diameter of the rotor body (100) is 3-4 times the diameter of the hollow shaft (500).

9. An electric machine rotor structure, according to claim 7, characterized in that said aperture (400) is a flat hollow cylindrical structure, between the two ends of each pair of magnets (200) that are distant from each other.

10. An electric machine rotor structure according to any of claims 1-9, characterized in that the cooling cavity (300) is a cavity structure enclosed by an end plate (600) and an end of the rotor body (100).

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