A high power density motor cooling structure and cooling method thereof

Abstract

The present invention discloses a high power density motor cooling structure and a cooling method thereof, comprising a casing, end covers are respectively provided at the front and rear ends of the casing, a closed cooling chamber is formed between the end covers and the casing, oil inlet ring grooves are provided on both sides of the stator oil separator ring and at the outer edge around the center line of the rotating shaft, an oil inlet chamber is formed between the oil inlet ring groove and the stator iron core on its side, an oil inlet port connected to two oil inlet chambers is provided on one side of the casing, an oil drain port connected to the cooling chamber is provided on the side of the casing facing away from the oil inlet port, the oil drain port is close to one of the end covers, a plurality of oil inlet channels extending parallel to the center line of the stator iron core are provided on the stator iron core, and the oil inlet channels are respectively connected to the oil inlet chamber and the cooling chamber. The cooling efficiency is improved, the motor cooling effect is improved, and the motor power density is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of motors, and in particular to a high power density motor cooling structure and a cooling method thereof. Background Art

[0002] High power density motors have the advantages of small size, power density, high efficiency, low motor material consumption, and low cost, and are increasingly attracting the attention of motor developers and manufacturers. When the motor converts electrical energy into mechanical energy, losses will occur, causing the motor temperature to rise. Especially for high power density motors, the losses are large and the temperature rises quickly, which can easily reduce the life of the motor and have a great impact on the normal use of the motor. Reasonable design of motor cooling method can not only improve the power density per unit volume of the motor, but also improve the stability of the motor operation and the life of the motor insulation structure.

[0003] However, conventional motor cooling generally uses air ducts to cool the motor housing or water channels to cool the motor housing. The motor rotor generates the largest loss, accounting for about 30% of the total motor loss. If a large amount of loss is not converted out through the cooling medium, it will generate very high temperatures on the motor parts. High temperatures will not only have a great impact on the insulation life of the motor, but also the temperature on the rotor parts will be transmitted to the bearings through the shaft, causing the bearing temperature to be too high, the bearing grease to fail, and the bearing life to be shortened. The single cooling method of the traditional motor only has a good cooling effect on the stator part of the motor, and the cooling effect is relatively poor, which in turn affects the use of the motor.

[0004] Therefore, it is of great significance to develop new structural cooling methods, improve cooling efficiency, improve motor cooling effects, and increase motor power density. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, an object of the present invention is to provide a high power density motor cooling structure and a cooling method thereof which can improve cooling efficiency and motor cooling effect.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A high power density motor cooling structure comprises a casing, wherein end covers are respectively provided at the front and rear ends of the casing, a closed cooling chamber is formed between the end covers and the casing, a rotating shaft passes through the casing, and the structure is characterized in that a stator oil separator ring coaxial with the rotating shaft is provided in the casing and located in the middle position of the casing along the front and rear direction thereof, and a stator core coaxial with the rotating shaft is respectively provided in the casing and located on both sides of the stator oil separator ring coaxial with the rotating shaft, the stator core is fixedly sealed with the stator oil separator ring at one end of the stator core facing the stator oil separator ring, the stator core is fixedly sealed and connected to the inner surface of the casing, a plurality of winding wire slots A are evenly spaced on the inner surface of the stator core around the center line direction thereof, the winding wire slots A are through slots and extend in a direction parallel to the center line of the rotating shaft, the winding wire slots A on the two stator cores are respectively provided correspondingly, and the inner surface of the stator oil separator ring corresponds to each winding wire slot A Winding wire slots B are respectively opened at the positions, the winding wire slots B are through slots and extend in a direction parallel to the center line of the rotating shaft, a winding cable is arranged between the two corresponding winding wire slots A on the two stator cores, the winding cable passes through the corresponding winding wire slots B and its two ends extend out from the opposite ends of the two winding wire slots respectively, oil inlet ring grooves are arranged on the two side surfaces of the stator oil separator ring and at the position of the outer edge around the center line of the rotating shaft, an oil inlet chamber is formed between the oil inlet ring groove and the stator core on its side, an oil inlet port connected with the two oil inlet chambers is respectively provided on one side surface of the casing, an oil drain port connected with the cooling chamber is provided on the side surface of the casing and opposite to the oil inlet port, the oil drain port is close to one of the end covers, a plurality of oil inlet channels extending in a direction parallel to the center line of the stator core are provided, and the oil inlet channels are respectively connected with the oil inlet chamber and the cooling chamber;

[0008] The rotating shaft is sleeved with a rotor oil-slinging ring which is fixedly sealed with the rotating shaft. The rotor oil-slinging ring is located in the middle position of the casing along the front-rear direction of the casing. The inner side surface of the rotor oil-slinging ring is provided with an annular groove which is coaxial with the rotating shaft. An oil-slinging chamber is formed between the annular groove and the rotating shaft. A closed chamber for accommodating cooling oil is provided in the rotating shaft. An oil delivery port which is connected to the closed chamber is opened along the center line direction of the rotating shaft at one end portion of the rotating shaft. A plurality of oil-slinging holes I are evenly spaced around the center line direction of the rotating shaft at the position corresponding to the oil-slinging chamber on the rotating shaft. The oil-slinging holes I extend in the radial direction of the rotating shaft. The closed chamber is connected to the oil-slinging chamber through the oil-slinging holes I. A plurality of squirrel cage perforations A which extend in a direction parallel to the center line of the rotating shaft are evenly spaced around the center line direction of the rotating shaft on the rotor oil-slinging ring. Rotor cores which are coaxial with the rotating shaft are respectively provided on the rotating shaft and located on both sides of the rotor oil-slinging ring. The rotor core faces the rotor oil-slinging ring. One end is fixedly connected with the rotor oil slinger ring, and the positions corresponding to each squirrel cage through-hole A on the rotor core are respectively provided with squirrel cage through-holes B in a direction parallel to the center line of the rotating shaft, and a squirrel cage winding cable is arranged between the two corresponding squirrel cage through-holes B on the two rotor cores, and the squirrel cage winding cable passes through the corresponding squirrel cage through-holes A and its two ends extend from the opposite ends of the two squirrel cage through-holes B respectively, and the squirrel cage winding cable is respectively fitted with the inner wall of the squirrel cage through-hole A and the inner wall of the squirrel cage through-hole B, and a cooling oil hole is pierced on the squirrel cage winding cable in a direction parallel to the center line of the rotating shaft, and a connecting hole A extending in the radial direction of the rotating shaft and connected with the cooling oil hole is opened on the squirrel cage winding cable on one side surface facing the rotor oil slinger ring and corresponding to the position of the rotor oil slinger ring, and a connecting hole B coaxial with the connecting hole A is pierced on the groove bottom of the annular groove at a position corresponding to each connecting hole A, and the cooling oil hole is connected with the oil slinger cavity through the connecting hole A and the connecting hole B.

[0009] This scheme designs two cooling modes for the main components of the motor that generate heat (winding cables, i.e., stator coils, stator cores, and squirrel cage windings). The two modes run synchronously. The first mode is stator oil circuit cooling. A plurality of oil inlet channels extending parallel to the center line are provided on the stator core. The oil inlet channels are connected to the oil inlet chamber and the cooling chamber respectively. The cooling oil enters the oil inlet chamber from the oil inlet port and is divided in the oil inlet chamber to form a plurality of oil inlet channels to cool the stator core. At the same time, the two stator cores are located on both sides of the stator oil separator ring. In this way, the cooling oil enters from the two oil inlets respectively and flows into the corresponding oil inlet chamber respectively. In this way, the stator core and the winding cables can be quickly cooled. After cooling, the oil is collected in the cooling chamber and discharged from the oil drain port.

[0010] The second mode is rotor oil circuit cooling, which delivers cooling oil to the closed chamber in the rotating shaft through the oil delivery port. In actual operation, under the action of external oil pressure and centrifugal force, the cooling oil in the closed chamber will enter the annular groove of the rotor oil slinger ring through the oil slinging hole Ⅰ of the rotating shaft, and an oil slinging chamber is formed between the annular groove and the rotating shaft. The cooling oil then enters the cooling oil hole through the connecting hole A and the connecting hole B through the oil slinging chamber to cool the squirrel cage winding. The cooled cooling oil is collected in the cooling chamber through the cooling oil hole and then discharged from the oil discharge port.

[0011] This solution adopts oil cooling, and the cooling medium directly reaches the heating parts inside the motor, that is, directly cools the heating parts of the motor stator core, winding cables and squirrel cage windings, with good cooling effect, which increases the service life of the motor, and cools the stator and rotor at the same time, improving the cooling efficiency.

[0012] Furthermore, the plurality of oil inlet channels include an oil channel I located outside the bottom of the winding slot A and an oil channel II located between two adjacent winding slots A. The stator core is composed of a plurality of overlapping stator punching sheets. All stator punching sheets are respectively provided with staggered holes I at positions outside the bottom of the winding slot A. The projections of two adjacent staggered holes I along the direction parallel to the center line of the rotating shaft overlap. All staggered holes I are connected in sequence to form oil channel I. All stator punching sheets are respectively provided with staggered holes II at positions between two adjacent winding slots A. The projections of two adjacent staggered holes II along the direction parallel to the center line of the rotating shaft overlap. All staggered holes II are connected in sequence to form oil channel II.

[0013] Among them, the staggered hole I includes transverse hole I and transverse hole II, and the staggered hole II includes vertical hole I and vertical hole II. Such a design allows the oil channel I and the oil channel II to form a staggered distribution of flow channels, increasing the turbulence effect in the flow channel, and the turbulence can greatly enhance the heat transfer coefficient and achieve better heat transfer effect.

[0014] Furthermore, the upper inner surface and the lower inner surface of the transverse hole I and the transverse hole II are both wavy.

[0015] This design increases the heat exchange area. When the cooling oil passes through the oil channel I, the cooling oil medium is violently mixed on the wavy upper and lower inner surfaces of the transverse holes I and II, which greatly enhances the heat exchange and increases the heat exchange capacity.

[0016] Furthermore, a stator oil spray ring arranged coaxially with the rotating shaft is arranged in the casing and respectively located at the outer sides of the two stator cores, the stator oil spray ring is fixedly and sealedly connected to the inner surface of the casing, an oil spray groove coaxially with the stator oil spray ring is recessed on a side surface of the stator oil spray ring facing the stator core, the stator oil spray ring is fixedly and sealedly connected to the outer side surface of the stator core corresponding to the side on which it is located, an oil spray chamber is formed between the oil spray groove and the stator core corresponding to the side on which it is located, connecting holes extending in a direction parallel to the center line of the stator core are evenly spaced around the center line direction of the stator core, the connecting holes form an oil passage III, the two ends of the oil passage III are respectively connected to the oil spray chamber and the oil inlet chamber, and a plurality of oil spray holes extending in a radial direction of the rotating shaft and connected to the oil spray chamber are evenly spaced around the center line direction of the stator oil spray ring on the inner side surface.

[0017] The oil channel III designed in the stator oil circuit cooling mode of this scheme introduces cooling oil into the oil channel III through the oil inlet, and introduces cooling oil into the oil injection chamber through the oil outlet of the oil channel III. Under the action of external pressure, the cooling oil in the oil injection chamber is sprayed to the end position of the winding cable through the oil injection hole to cool the end position of the winding cable, and then it is collected in the cooling chamber and discharged through the oil discharge port.

[0018] Furthermore, oil guide grooves respectively connected with the oil passage II and the oil inlet chamber are provided on both side surfaces of the stator oil separator ring and respectively correspond to the positions of the oil passage II, and the projection of the oil passage II along the center line of the rotating shaft is located within the projection of the oil guide groove along the center line of the rotating shaft.

[0019] The stator oil separator ring in this scheme has three functions. The first function is that the stator oil separator ring is arranged in the middle position of the stator core, and the side of the stator oil separator ring is in contact with the stator core, so as to seal the cooling oil and prevent the cooling oil from leaking. The second function is that the stator oil separator ring divides the stator core into two independent parts, thereby forming oil channel I, oil channel II and oil channel III on the left and right sides of the stator core, so that the cooling oil can flow to the oil channel I, oil channel II and oil channel III on both sides at the same time, thus shortening the cooling time and improving the cooling efficiency. The third function is the drainage function of the stator oil separator ring, and the oil guide groove of the stator oil separator ring introduces the cooling oil into the oil channel II.

[0020] Furthermore, the shaft body of the rotating shaft located on the inner side of the rotor core is evenly spaced around the center line of the rotating shaft with a plurality of oil-slinging holes II, the oil-slinging holes II extending in the radial direction of the rotating shaft and being connected with the closed chamber, the shaft body of the rotating shaft is provided with an oil guide groove located at the outer opening of the oil-slinging hole II along a direction parallel to the center line of the rotating shaft, one end of the oil guide groove is connected with the corresponding oil-slinging hole II, and the other end extends in a direction opposite to the rotor oil-slinging ring and extends out of the rotor core on its side.

[0021] In this scheme, there are two groups of oil-slinging holes II in the rotor oil circuit cooling mode. Under the action of external air pressure and centrifugal force, the cooling oil in the closed chamber will enter the oil inlet groove through the oil-slinging hole II of the rotating shaft. The oil inlet groove introduces the cooling oil to the outer end of the rotor core to cool the outer end of the rotor core, and then it is collected in the cooling chamber and discharged from the oil drain port; at the same time, when the cooling oil flows out from the two groups of oil inlet grooves, it also cools the rotating shaft to prevent the high heat of the rotating shaft from being transferred to the bearing; and part of the cooling oil will also be sprayed onto the bearing, which also cools the bearing to prevent the heat of the rotor core from being transferred to the bearing through the rotating shaft.

[0022] Furthermore, an oil inlet pipe coaxial with the rotating shaft is provided at one end of the rotating shaft located at the oil delivery port, the oil outlet end of the oil inlet pipe passes through the oil delivery port and extends into the closed chamber, the oil inlet pipe is spaced apart from the inner wall of the oil delivery port, and a sealing ring that can respectively seal with the oil inlet pipe and the oil delivery port is sleeved on the pipe body of the oil inlet pipe located between the oil inlet pipe and the oil delivery port.

[0023] In this solution, the cooling oil is introduced into the closed chamber through the oil inlet pipe. At the same time, the sealing ring on the outer surface of the oil inlet pipe cooperates with the oil delivery port to prevent leakage of the cooling oil.

[0024] Furthermore, the size of the oil-slinging hole I is larger than the size of the oil-slinging hole II.

[0025] In this scheme, the size of oil-fling hole I is designed to be larger than that of oil-fling hole II. This is because there is only one group of oil-fling hole I, and oil-fling hole I needs to introduce a large amount of cooling oil into the rotor oil-fling ring before the cooling oil can be introduced into the cooling oil holes of the squirrel cage winding. Oil-fling hole II has two groups and is mainly used to cool the surface of the rotating shaft. The oil path of its cooling oil is closer than that of oil-fling hole I. Therefore, less cooling oil is required. In this way, the amount of cooling oil is limited by the size of oil-fling hole I and oil-fling hole II.

[0026] Furthermore, the squirrel cage winding cable is provided with a plurality of process holes corresponding to the connection holes along the circumferential direction, the upper port of the process hole passes through the squirrel cage winding cable, and the lower port of the process hole is connected to the cooling oil hole of the rotor oil slinger.

[0027] The process holes set in this scheme do not play any role in the rotor oil circuit cooling mode. The process holes are set only to remove the chips generated by drilling when processing the cooling oil holes for the squirrel cage winding, so as to avoid the chips clogging the cooling oil holes during processing. At the same time, the process hole processing is to clear the cooling oil holes blocked in the aluminum casting process.

[0028] Furthermore, the outer surface of the process hole is sleeved with a rotor oil sealing ring in an annular structure. In this solution, the rotor oil sealing ring is provided to seal the cooling oil to prevent the cooling oil from leaking.

[0029] Furthermore, slot insulation is provided on the inner surface of the winding slot A. The slot insulation is used to strengthen the insulation between the stator winding and the stator core.

[0030] A cooling method for a high power density motor cooling structure, the cooling method is applied to the high power density motor cooling structure, the cooling method for the motor cooling structure comprises: cooling oil enters the oil inlet chamber through two oil inlets respectively, is split through the oil inlet chamber to form three oil channels, and flows into a plurality of oil inlet channels respectively, when the cooling oil flows through the oil inlet channels, it takes away the heat of the stator core and the heat transferred by the winding cable in the winding wire slot A, cools the winding cable and the stator core, after cooling, the cooling oil is concentrated in the cooling chamber and discharged through the oil outlet;

[0031] At the same time, the cooling oil enters the closed chamber of the rotating shaft through the oil delivery port. Under the action of external oil pressure and centrifugal force, the cooling oil flows into the annular groove of the rotor oil-slinging ring when passing through the oil-slinging hole Ⅰ of the rotating shaft. An oil-slinging chamber is formed between the annular groove and the rotating shaft. The cooling oil then enters the cooling oil hole through the connecting hole A and the connecting hole B through the oil-slinging chamber to cool the squirrel cage winding. The cooled cooling oil is collected in the cooling chamber through the cooling oil hole and then discharged from the oil drain port.

[0032] Furthermore, when the cooling oil flows through the oil channel I, it will take away the heat of the stator core and the heat transferred by the winding cable on the outside of the bottom of the winding slot A, and cool the winding cable and the stator core; when the cooling oil flows through the oil channel II, it will take away the heat of the stator core and the heat transferred by the winding cable between the two winding slots A, and cool the winding cable and the stator core. When the cooling oil flows through the oil channel III, the oil channel III introduces the cooling oil into the injection cavity of the stator injection ring. Under the action of the external oil pressure, the cooling oil in the injection cavity is sprayed to the end position of the winding cable through the injection hole, and the end position of the winding cable and the stator core are cooled; after cooling, the cooling oil of the oil channel I, the oil channel II and the oil channel III are concentrated in the cooling cavity and discharged through the oil drain port.

[0033] Furthermore, the cooling oil enters the closed chamber of the rotating shaft through the oil delivery port. Under the action of external oil pressure and centrifugal force, the cooling oil in the closed chamber will enter the oil inlet groove through the oil throwing hole II of the rotating shaft. The oil inlet groove introduces the cooling oil to the outer end of the rotor core. After cooling, the cooling oil flows into the cooling chamber and is discharged from the oil drain port.

[0034] Compared with the prior art, the present invention has the following advantages:

[0035] 1. This scheme adopts two oil cooling methods, namely stator oil circuit cooling and rotor oil circuit cooling, wherein the stator oil circuit cooling is divided into oil circuit channel I, oil circuit channel II, and oil circuit channel III, and the stator oil separator ring divides the oil circuit channel I, oil circuit channel II, and oil circuit channel III into two, and the two sides of the stator oil separator ring correspond to the two oil inlets set on the casing respectively, the oil inlet chamber in the stator oil separator ring corresponds to the oil circuit channel I and the oil circuit channel III, and the oil guide groove set on the stator oil separator ring corresponds to the oil circuit channel II;

[0036] In this way, the cooling oil enters the oil inlet chamber and the oil guide groove on both sides of the stator oil separator ring through two oil inlets, and enters the oil channel I, oil channel II, and oil channel III respectively. The oil channel I and oil channel II are close to the winding cable parts with the most serious heat generation and the parts with large eddy current losses on the stator core. The cooling oil will take away the heat on the winding cables and the stator core through the oil channel I and oil channel II to cool the stator as a whole; the oil channel III enters the oil injection chamber of the stator oil injection ring. Under the action of external pressure, the cooling oil in the oil injection chamber is sprayed to the end position of the winding cable through the oil injection hole to cool the end position of the winding cable; this scheme uses the three cooling channels of oil channel I, oil channel II, and oil channel III to cool different positions of the stator core in a targeted manner, thereby improving the efficiency of stator cooling;

[0037] When the stator oil circuit cooling mode is in progress, the rotor oil circuit cooling mode is also in progress at the same time, so that the cooling oil is transported to the closed chamber in the rotating shaft through the oil delivery port. In actual work, under the action of external air pressure and centrifugal force, the cooling oil in the closed chamber will enter the annular groove of the rotor oil-slinging ring through the oil-slinging hole Ⅰ of the rotating shaft, and an oil-slinging chamber is formed between the annular groove and the rotating shaft. The cooling oil then enters the cooling oil hole through the connecting hole A and the connecting hole B through the oil-slinging chamber to cool the squirrel cage winding, and the cooled cooling oil is collected in the cooling chamber through the cooling oil hole and then discharged from the oil drain port; at the same time, the cooling oil in the closed chamber will enter the oil inlet groove through the oil-slinging hole Ⅱ of the rotating shaft, and the oil inlet groove will introduce the cooling oil to the outer end of the rotor core to prevent the high heat of the rotating shaft from being transferred to the bearing.

[0038] 2. This solution uses the cooling oil medium to directly reach the heating parts of the motor (winding cables, stator punchings, squirrel cage windings and bearings). The overall structure is compact, the performance is stable, and the cost is low. The cooling effect is good and high power density can be achieved. The service life of the motor is improved. The motor adopts a fully sealed structure with low noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a structural schematic diagram of the high power density motor cooling structure of the present invention;

[0040] Figure 2 for Figure 1 Sectional view of AA in the middle;

[0041] Figure 3 It is a structural schematic diagram of the oil passage I in the high power density motor cooling structure of the present invention;

[0042] Figure 4 It is a structural schematic diagram of the oil passage II in the high power density motor cooling structure of the present invention;

[0043] Figure 5 It is a structural schematic diagram of the stator punching sheet I in the high power density motor cooling structure of the present invention;

[0044] Figure 6 for Figure 5 A partial enlarged view of point B in the middle;

[0045] Figure 7 It is a structural schematic diagram of stator punching sheet II in the high power density motor cooling structure of the present invention;

[0046] Figure 8 for Figure 7 A partial enlarged view of point C in the middle;

[0047] Fig. 9 It is a structural schematic diagram of a stator oil separator ring in the high power density motor cooling structure of the present invention;

[0048] Fig.10 It is a structural schematic diagram of a rotor oil slinger in a high power density motor cooling structure of the present invention;

[0049] Fig.11 It is a structural schematic diagram of the connection between the rotor oil-slinger ring and the squirrel-cage winding in the high power density motor cooling structure of the present invention.

[0050] In the figure: end cover 1, casing 2, stator oil injection ring 3, stator punching sheet I4, stator punching sheet II5, stator oil separator ring 6, slot insulation 7, winding cable 8, bearing 9, sealing ring 10, oil inlet pipe 11, rotating shaft 12, rotor core 13, squirrel cage winding 14, rotor oil sealing ring 15, rotor oil throwing ring 16, transverse hole I 17, vertical hole I 18, transverse hole II 19, vertical hole II 20, oil inlet ring groove 21, oil guide groove 22, oil throwing hole I 23, oil throwing hole II 24, oil guide groove 25, oil inlet port 26, oil discharge port 27, oil injection hole 28, connecting hole 29, cooling oil hole 30, connecting hole A 31, annular groove 32, rotor groove 33. DETAILED DESCRIPTION

[0051] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0052] This example: See Figures 1 to 11 A high power density motor cooling structure and a cooling method thereof, wherein a high power density motor cooling structure comprises a casing 2, end covers 1 are respectively provided at the front and rear ends of the casing 2, a closed cooling chamber is formed between the end cover 1 and the casing 2, a rotating shaft 12 runs through the casing 2, a stator oil separator ring 6 which is coaxial with the rotating shaft 12 is provided in the casing 2 and located in the middle position of the casing 2 along the front and rear direction thereof, a stator core which is coaxial with the rotating shaft 12 is respectively provided in the casing 2 and located on both sides of the stator oil separator ring 6 coaxial with the rotating shaft 12, one end of the stator core facing the stator oil separator ring 6 is fixedly sealed with the stator oil separator ring 6, the stator core is fixedly sealed and connected to the inner surface of the casing 2, a plurality of winding wire slots A are evenly spaced on the inner surface of the stator core around the center line direction thereof, the winding wire slots A are through slots and extend in a direction parallel to the center line of the rotating shaft 12, the winding wire slots A on the two stator cores are respectively provided correspondingly, and on the inner surface of the stator oil separator ring 6 Winding wire slots B are respectively opened at the positions corresponding to each winding wire slot A. The winding wire slots B are through slots and extend in a direction parallel to the center line of the rotating shaft 12. A winding cable 8 is arranged between the two corresponding winding wire slots A on the two stator cores. The winding cable 8 passes through the corresponding winding wire slots B and its two ends extend out from the opposite ends of the two winding wire slots respectively. Oil inlet ring grooves 21 are arranged on the two side surfaces of the stator oil separator 6 and at the positions of the outer edges around the center line of the rotating shaft 12. An oil inlet chamber is formed between the oil inlet ring groove 21 and the stator core on its side. An oil inlet port 26 connected to the two oil inlet chambers is respectively provided on one side surface of the casing 2. An oil drain port 27 connected to the cooling chamber is provided on the side surface of the casing 2 and on the side opposite to the oil inlet port 26. The oil drain port 27 is close to one of the end covers 1. A plurality of oil inlet channels extending in a direction parallel to the center line of the stator core are provided on the stator core. The oil inlet channels are respectively connected to the oil inlet chamber and the cooling chamber.

[0053] The rotating shaft 12 is sleeved with a rotor oil slinger 16 which is fixedly sealed therewith. The rotor oil slinger 16 is located in the middle position of the casing 2 along the front-rear direction of the casing 2. The inner side surface of the rotor oil slinger 16 is provided with an annular groove 32 which is coaxial with the inner side surface of the rotor oil slinger 16. An oil slinger cavity is formed between the annular groove 32 and the rotating shaft 12. A closed cavity for accommodating cooling oil is provided in the rotating shaft 12. An oil delivery port which is connected to the closed cavity is provided at one end of the rotating shaft 12 along the center line thereof. The position of the corresponding oil slinger cavity on the rotating shaft 12 is around the rotating shaft. A plurality of oil-slinging holes Ⅰ23 are evenly spaced in the direction of the center line of the rotating shaft 12, and the oil-slinging holes Ⅰ23 extend in the radial direction of the rotating shaft 12. The closed chamber is connected to the oil-slinging cavity through the oil-slinging holes Ⅰ23. A plurality of squirrel cage perforations A extending in a direction parallel to the center line of the rotating shaft 12 are evenly spaced in the direction of the center line of the rotating shaft 12 on the rotor oil-slinging ring 16. The rotor cores 13 that are the same center line as the rotating shaft 12 are respectively arranged on the rotating shaft 12 and located on both sides of the rotor oil-slinging ring 16. The rotor cores 13 face the rotor oil-slinging ring 16. One end of 16 is fixedly connected to the rotor oil slinger 16, and positions corresponding to each squirrel cage through-hole A on the rotor core 13 are respectively provided with squirrel cage through-holes B in a direction parallel to the center line of the rotating shaft 12, and a squirrel cage winding cable 8 is arranged between two corresponding squirrel cage through-holes B on the two rotor cores 13, and the squirrel cage winding cable 8 passes through the corresponding squirrel cage through-holes A and its two ends extend from the opposite ends of the two squirrel cage through-holes B respectively, and the squirrel cage winding cable 8 is respectively in contact with the inner wall of the squirrel cage through-hole A and the inner wall of the squirrel cage through-hole B, A cooling oil hole 30 is provided on the squirrel cage winding cable 8 in a direction parallel to the center line of the rotating shaft 12. A connecting hole A31 extending in the radial direction of the rotating shaft 12 and connected to the cooling oil hole 30 is provided on the squirrel cage winding cable 8 on one side surface facing the rotor oil slinger 16 and corresponding to the position of the rotor oil slinger 16. A connecting hole B coaxial with the connecting hole A31 is provided on the bottom of the annular groove 32 at positions corresponding to each connecting hole A31. The cooling oil hole 30 is connected to the oil slinging chamber through the connecting hole A31 and the connecting hole B.

[0054] This solution designs two cooling modes for the main components of the motor that generate heat (winding cable 8, i.e., stator coil, stator core, and squirrel cage winding 14). The two modes run synchronously. The first mode is stator oil circuit cooling. A plurality of oil inlet channels extending parallel to the center line direction are provided on the stator core. The oil inlet channels are connected to the oil inlet chamber and the cooling chamber respectively. The cooling oil enters the oil inlet chamber from the oil inlet port 26 and is divided in the oil inlet chamber to form a plurality of oil inlet channels to cool the stator core. At the same time, the two stator cores are located on both sides of the stator oil separator ring 6. In this way, the cooling oil enters from the two oil inlets 26 respectively and flows into the corresponding oil inlet chamber respectively. In this way, the stator core and the winding cable 8 can be quickly cooled. After cooling, the oil is collected in the cooling chamber and discharged from the oil outlet 27.

[0055] The second mode is rotor oil circuit cooling, which delivers cooling oil to the closed chamber in the rotating shaft 12 through the oil delivery port. In actual operation, under the action of external oil pressure and centrifugal force, the cooling oil in the closed chamber will enter the annular groove 32 of the rotor oil slinger 16 through the oil slinging hole I23 of the rotating shaft 12, and an oil slinging chamber is formed between the annular groove 32 and the rotating shaft 12. The cooling oil then enters the cooling oil hole 30 through the connecting hole A31 and the connecting hole B through the oil slinging chamber to cool the squirrel cage winding 14, and the cooled cooling oil is collected in the cooling chamber through the cooling oil hole 30 and then discharged from the oil discharge port 27.

[0056] This solution adopts oil cooling, and the cooling medium directly reaches the heating parts inside the motor, that is, directly cools the heating parts of the motor stator core, winding cable 8 and squirrel cage winding 14, with good cooling effect, improving the service life of the motor, and cooling the stator and rotor at the same time to improve the cooling efficiency.

[0057] Preferably, the multiple oil inlet channels include an oil channel I located outside the bottom of the winding slot A and an oil channel II located between two adjacent winding slots A. The stator core is composed of a plurality of overlapping stator punchings, and the stator punchings include stator punchings I4 and stator punchings II5. All stator punchings are respectively provided with staggered holes I at positions outside the bottom of the winding slot A, and the projections of two adjacent staggered holes I along the direction parallel to the center line of the rotating shaft 12 overlap, and all the staggered holes I are connected in sequence to form the oil channel I. All stator punchings are respectively provided with staggered holes II at positions between two adjacent winding slots A, and the projections of two adjacent staggered holes II along the direction parallel to the center line of the rotating shaft 12 overlap, and all the staggered holes II are connected in sequence to form the oil channel II.

[0058] Among them, the staggered hole I includes a transverse hole I 17 and a transverse hole II 19, and the staggered hole II includes a vertical hole I 18 and a vertical hole II 20. Such a design allows the oil channel I and the oil channel II to form a staggered distribution of flow channels, increasing the turbulence effect in the flow channel, and the turbulence can greatly enhance the heat transfer coefficient and achieve a better heat transfer effect.

[0059] Preferably, the upper inner surface and the lower inner surface of the transverse hole I 17 and the transverse hole II 19 are both wavy.

[0060] This design increases the heat exchange area. When the cooling oil passes through the oil channel I, the cooling oil medium is vigorously mixed on the wavy upper and lower inner surfaces of the transverse holes I 17 and II 19, which greatly enhances the heat exchange and increases the heat exchange capacity.

[0061] Preferably, a stator oil injection ring 3 which is arranged coaxially with the rotating shaft 12 is provided in the casing 2 and at a position respectively located outside the two stator cores. The stator oil injection ring 3 is fixedly and sealedly connected to the inner surface of the casing 2. A side surface of the stator oil injection ring 3 facing the stator core is concavely provided with an oil injection groove coaxially with the stator oil injection ring 3. The side surface of the stator oil injection ring 3 facing the stator core is fixedly and sealedly connected to the outer side surface of the stator core corresponding to the side on which it is located. An oil injection cavity is formed between the oil injection groove and the stator core corresponding to the side on which it is located. The stator core is provided with connecting holes 29 extending in a direction parallel to its center line at even intervals around its center line direction. The connecting holes 29 form an oil passage III. The two ends of the oil passage III are respectively connected to the oil injection cavity and the oil inlet chamber. The inner side surface of the stator oil injection ring 3 is provided with a plurality of oil injection holes 28 extending in the radial direction of the rotating shaft 12 and connected to the oil injection cavity at even intervals around its center line direction.

[0062] The oil channel III designed in the stator oil circuit cooling mode of this scheme introduces cooling oil into the oil channel III through the oil inlet 26, and introduces the cooling oil into the oil injection chamber through the oil outlet end of the oil channel III. Under the action of external pressure, the cooling oil in the oil injection chamber is sprayed to the end position of the winding cable 8 through the oil injection hole 28 to cool the end position of the winding cable 8, and then it is collected in the cooling chamber and discharged through the oil discharge port 27.

[0063] Preferably, oil guide grooves 22 respectively connected with the oil passage II and the oil inlet chamber are provided on both side surfaces of the stator oil separator ring 6 and correspond to the positions of each oil passage II. The projection of the oil passage II along the center line of the rotating shaft 12 is located within the projection of the oil guide groove 22 along the center line of the rotating shaft 12.

[0064] The stator oil separator ring 6 in this scheme has three functions. The first function is that the stator oil separator ring 6 is arranged in the middle position of the stator core, and the side surface of the stator oil separator ring 6 is in contact with the stator core, which plays a role in sealing the cooling oil and preventing cooling oil leakage; the second function is that the stator oil separator ring 6 divides the stator core into two independent parts, thereby forming oil channel I, oil channel II and oil channel III on the left and right sides of the stator core, so that the cooling oil can flow to the oil channel I, oil channel II and oil channel III on both sides at the same time, shortening the cooling time and improving the cooling efficiency; the third function is the drainage function of the stator oil separator ring 6, and the oil guide groove 22 of the stator oil separator ring 6 introduces the cooling oil into the oil channel II.

[0065] Preferably, the shaft 12 and the shaft body located on the inner side of the rotor core 13 are provided with a plurality of oil-slinging holes II 24 evenly spaced around the center line direction of the shaft 12, the oil-slinging holes II 24 extend in the radial direction of the shaft 12 and are connected to the closed chamber, and the shaft body of the shaft 12 and the outer opening position of the oil-slinging holes II 24 are provided with oil guide grooves 25 parallel to the center line direction of the shaft 12, one end of the oil guide groove 25 is connected to the corresponding oil-slinging hole II 24, and the other end extends in the direction opposite to the rotor oil-slinging ring 16 and extends out of the rotor core 13 on its side.

[0066] In the present scheme, there are two groups of oil-slinging holes II 24 in the rotor oil circuit cooling mode. Under the action of external air pressure and centrifugal force, the cooling oil in the closed chamber will enter the oil introduction groove 25 through the oil-slinging holes II 24 of the rotating shaft 12. The oil introduction groove 25 introduces the cooling oil to the outer end of the rotor core 13 to cool the outer end of the rotor core 13, and then collects in the cooling chamber and is discharged from the oil discharge port 27; at the same time, when the cooling oil flows out from the two groups of oil introduction grooves 25, it also cools the rotating shaft 12, preventing the high heat of the rotating shaft 12 from being transferred to the bearing 9; and part of the cooling oil will also be sprayed onto the bearing 9, which also cools the bearing 9, preventing the heat of the rotor core 13 from being transferred to the bearing 9 through the rotating shaft 12.

[0067] Preferably, an oil inlet pipe coaxial with the rotating shaft 12 is provided at one end of the rotating shaft 12 located at the oil delivery port, the oil outlet end of the oil inlet pipe passes through the oil delivery port and extends into the closed chamber, the oil inlet pipe is spaced apart from the inner wall of the oil delivery port, and a sealing ring 10 is sleeved on the pipe body of the oil inlet pipe located between the oil inlet pipe and the oil delivery port, which can respectively cooperate with the oil inlet pipe and the oil delivery port in a sealing manner.

[0068] In this solution, the cooling oil is introduced into the closed chamber through the oil inlet pipe 11. At the same time, the sealing ring 10 on the outer surface of the oil inlet pipe 11 cooperates with the oil delivery port to prevent leakage of the cooling oil.

[0069] Preferably, the size of the oil-slinging hole I23 is larger than the size of the oil-slinging hole II24.

[0070] In this scheme, the size of the oil-fling hole I23 is designed to be larger than that of the oil-fling hole II24. This is because there is only one group of oil-fling holes I23, and the oil-fling holes I23 need to introduce a large amount of cooling oil into the rotor oil-fling ring 16 before the cooling oil can be introduced into the oil holes of the squirrel cage winding 14. The oil-fling holes II24 are in two groups, and are mainly used to cool the surface of the rotating shaft 12. The oil path of the cooling oil is closer than that of the oil-fling holes I23. Therefore, less cooling oil is required. In this way, the amount of cooling oil is limited by the size of the oil-fling holes I23 and the oil-fling holes II24.

[0071] Preferably, the squirrel cage winding 14 is provided with a plurality of process holes corresponding to the connection holes A31 along the circumferential direction, the upper ports of the process holes pass through the squirrel cage winding 14 , and the lower ports of the process holes are connected to the cooling oil holes of the rotor oil slinger 16 .

[0072] The process holes set in this scheme do not play any role in the rotor oil circuit cooling mode. The process holes are set only to remove the chips generated by drilling when processing the cooling oil holes for the squirrel cage winding 14, so as to avoid the chips clogging the cooling oil holes during processing. At the same time, the process hole processing is to clear the cooling oil holes blocked in the aluminum casting process.

[0073] Preferably, the outer surface of the process hole is sleeved with a rotor oil sealing ring 15 in an annular structure. In this solution, the rotor oil sealing ring 15 is used to seal the cooling oil to prevent the cooling oil from leaking.

[0074] Preferably, the inner surface of the winding slot A is provided with a slot insulation 7. The slot insulation 7 serves to strengthen the insulation between the stator winding and the stator core.

[0075] A cooling method for a high power density motor cooling structure, the cooling method is applied to a high power density motor cooling structure, the cooling method for the motor cooling structure comprises: cooling oil enters the oil inlet chamber through two oil inlets 26 respectively, is divided into three oil channels through the oil inlet chamber, and flows into a plurality of oil inlet channels respectively, when the cooling oil flows through the oil inlet channel, it will take away the heat of the stator core and the heat transferred by the winding cable 8 in the winding wire slot A, and cool the winding cable 8 and the stator core, after cooling, the cooling oil is concentrated in the cooling chamber and discharged through the oil discharge port 27;

[0076] At the same time, the cooling oil enters the closed chamber of the rotating shaft 12 through the oil delivery port. Under the action of external oil pressure and centrifugal force, the cooling oil flows into the annular groove 32 of the rotor oil-slinging ring 16 when passing through the oil-slinging hole Ⅰ23 of the rotating shaft 12. An oil-slinging chamber is formed between the annular groove 32 and the rotating shaft 12. The cooling oil then enters the cooling oil hole 30 through the connecting hole A31 and the connecting hole B through the oil-slinging chamber to cool the squirrel cage winding 14. The cooled cooling oil is collected in the cooling chamber through the cooling oil hole 30 and then discharged from the oil drain port 27.

[0077] Preferably, when the cooling oil flows through the oil channel I, it will take away the heat of the stator core and the heat transferred by the winding cable 8 to the outside of the bottom of the winding slot A, thereby cooling the winding cable 8 and the stator core; when the cooling oil flows through the oil channel II, it will take away the heat of the stator core and the heat transferred by the winding cable 8 between the two winding slots A, thereby cooling the winding cable 8 and the stator core; when the cooling oil flows through the oil channel III, the oil channel III introduces the cooling oil into the injection cavity of the stator injection ring 3, and under the action of the external oil pressure, the cooling oil in the injection cavity is sprayed to the end position of the winding cable 8 through the injection hole 28, thereby cooling the end position of the winding cable 8 and the stator core; after cooling, the cooling oil in the oil channel I, the oil channel II and the oil channel III are concentrated in the cooling cavity and discharged through the oil drain port 27.

[0078] Preferably, the cooling oil enters the closed chamber of the rotating shaft 12 through the oil delivery port. Under the action of external oil pressure and centrifugal force, the cooling oil in the closed chamber will enter the oil guide groove 25 through the oil throwing hole II 24 of the rotating shaft 12. The oil guide groove 25 introduces the cooling oil to the outer end of the rotor core 13. After cooling, the cooling oil flows into the cooling chamber and is discharged from the oil discharge port 27.

[0079] 1. This scheme adopts two oil cooling methods, namely stator oil circuit cooling and rotor oil circuit cooling, wherein the stator oil circuit cooling is divided into oil circuit channel I, oil circuit channel II, and oil circuit channel III, and the stator oil separator ring 6 divides the oil circuit channel I, oil circuit channel II, and oil circuit channel III into two, and the two sides of the stator oil separator ring 6 correspond to the two oil inlets 26 set on the casing 2, the oil inlet chamber in the stator oil separator ring 6 corresponds to the oil circuit channel I and the oil circuit channel III, and the oil guide groove 22 set on the stator oil separator ring 6 corresponds to the oil circuit channel II;

[0080] In this way, the cooling oil enters the oil inlet chamber and the oil guide groove 22 on both sides of the stator oil separator ring 6 through the two oil inlets 26, and enters the oil channel I, oil channel II, and oil channel III respectively. The oil channel I and oil channel II are close to the most seriously heated winding cable 8 and the part with large eddy current loss on the stator core. The cooling oil will take away the heat on the winding cable 8 and the stator core through the oil channel I and oil channel II, and cool the stator as a whole; the oil channel III enters the injection chamber of the stator injection ring 3, and under the action of external pressure, the cooling oil in the injection chamber is sprayed to the end position of the winding cable 8 through the injection hole 28 to cool the end position of the winding cable 8; this scheme uses the three cooling channels of the oil channel I, oil channel II, and oil channel III to cool different positions of the stator core in a targeted manner, thereby improving the efficiency of stator cooling;

[0081] When the stator oil circuit cooling mode is in progress, the rotor oil circuit cooling mode is also in progress at the same time, so that the cooling oil is transported to the closed chamber in the rotating shaft 12 through the oil delivery port. In actual operation, under the action of external air pressure and centrifugal force, the cooling oil in the closed chamber will enter the annular groove 32 of the rotor oil-slinging ring 16 through the oil-slinging hole Ⅰ23 of the rotating shaft 12, and an oil-slinging chamber is formed between the annular groove 32 and the rotating shaft 12. The cooling oil is then passed through the oil-slinging chamber to enter the cooling oil hole 30 through the connecting hole A31 and the connecting hole B to cool the squirrel cage winding 14, and the cooled cooling oil is collected in the cooling chamber through the cooling oil hole 30, and then discharged from the oil discharge port 27; at the same time, the cooling oil in the closed chamber will enter the oil guide groove 25 through the oil-slinging hole Ⅱ24 of the rotating shaft 12, and the oil guide groove 25 will introduce the cooling oil to the outer end of the rotor core 13 to prevent the high heat of the rotating shaft 12 from being transferred to the bearing 9.

[0082] 2. This solution uses the cooling oil medium to directly reach the heating parts of the motor (winding cable 8, stator punching sheet, squirrel cage winding 14 and bearing 9). The overall structure is compact, the performance is stable, and the cost is low; the cooling effect is good and high power density can be achieved; the service life of the motor is improved; the motor adopts a fully sealed structure and has low noise.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the technical solution. Those skilled in the art should understand that those modifications or equivalent substitutions of the technical solution of the present invention that do not depart from the purpose and scope of the technical solution should be included in the scope of the claims of the present invention.

Claims

1. A high power density motor cooling structure, comprising a casing, wherein end covers are respectively provided at the front and rear ends of the casing, and a closed cooling chamber is formed between the end covers and the casing, and a rotating shaft passes through the casing, wherein: A stator oil separator ring coaxial with the rotating shaft is arranged in the casing and located in the middle position of the casing along the front-to-back direction thereof, and a stator core coaxial with the rotating shaft is arranged in the casing and located on both sides of the stator oil separator ring. The stator core is fixedly sealed with the stator oil separator ring at one end thereof facing the stator oil separator ring, and the stator core is fixedly sealed with the inner surface of the casing, and a plurality of winding wire grooves A are evenly spaced on the inner surface of the stator core around the center line thereof, and the winding wire grooves A are through grooves and extend in a direction parallel to the center line of the rotating shaft, and the winding wire grooves A located on the two stator cores are respectively arranged correspondingly, and winding wire grooves B are respectively opened on the inner surface of the stator oil separator ring at positions corresponding to each winding wire groove A, and the winding wire grooves B are through grooves and extend in a direction parallel to the center line of the rotating shaft. Extension, a winding cable is arranged between two corresponding winding slots A on the two stator cores, the winding cable passes through the corresponding winding slots B and its two ends extend out from the opposite ends of the two winding slots respectively, and oil inlet ring grooves are arranged on both side surfaces of the stator oil separator ring and located at the outer edge around the center line direction of the rotating shaft, and an oil inlet chamber is formed between the oil inlet ring groove and the stator core on its side, and an oil inlet port connected to the two oil inlet chambers is respectively provided on one side surface of the casing, and an oil drain port connected to the cooling chamber is provided on the side surface of the casing and opposite to the oil inlet port, and the oil drain port is close to one of the end covers, and a plurality of oil inlet channels extending parallel to the center line direction of the stator core are provided on the stator core, and the oil inlet channels are respectively connected to the oil inlet chamber and the cooling chamber; The rotating shaft is sleeved with a rotor oil-slinging ring which is fixedly sealed with the rotating shaft. The rotor oil-slinging ring is located in the middle position of the casing along the front-rear direction of the casing. The inner side surface of the rotor oil-slinging ring is provided with an annular groove which is coaxial with the rotating shaft. An oil-slinging chamber is formed between the annular groove and the rotating shaft. A closed chamber for accommodating cooling oil is provided in the rotating shaft. An oil delivery port which is connected to the closed chamber is opened along the center line direction of the rotating shaft at one end portion of the rotating shaft. A plurality of oil-slinging holes I are evenly spaced around the center line direction of the rotating shaft at the position corresponding to the oil-slinging chamber on the rotating shaft. The oil-slinging holes I extend in the radial direction of the rotating shaft. The closed chamber is connected to the oil-slinging chamber through the oil-slinging holes I. A plurality of squirrel cage perforations A which extend in a direction parallel to the center line of the rotating shaft are evenly spaced around the center line direction of the rotating shaft on the rotor oil-slinging ring. Rotor cores which are coaxial with the rotating shaft are respectively provided on the rotating shaft and located on both sides of the rotor oil-slinging ring. The rotor core faces the rotor oil-slinging ring. One end is fixedly connected with the rotor oil slinger ring, and the positions corresponding to each squirrel cage through-hole A on the rotor core are respectively provided with squirrel cage through-holes B in a direction parallel to the center line of the rotating shaft, and a squirrel cage winding cable is arranged between the two corresponding squirrel cage through-holes B on the two rotor cores, and the squirrel cage winding cable passes through the corresponding squirrel cage through-holes A and its two ends extend from the opposite ends of the two squirrel cage through-holes B respectively, and the squirrel cage winding cable is respectively fitted with the inner wall of the squirrel cage through-hole A and the inner wall of the squirrel cage through-hole B, and a cooling oil hole is pierced on the squirrel cage winding cable in a direction parallel to the center line of the rotating shaft, and a connecting hole A extending in the radial direction of the rotating shaft and connected with the cooling oil hole is opened on the squirrel cage winding cable on one side surface facing the rotor oil slinger ring and corresponding to the position of the rotor oil slinger ring, and a connecting hole B coaxial with the connecting hole A is pierced on the groove bottom of the annular groove at a position corresponding to each connecting hole A, and the cooling oil hole is connected with the oil slinger cavity through the connecting hole A and the connecting hole B.

2. A high power density motor cooling structure according to claim 1, characterized in that: The multiple oil inlet channels include an oil channel I located outside the bottom of the winding slot A and an oil channel II located between two adjacent winding slots A. The stator core is composed of a plurality of overlapping stator punching sheets. All stator punching sheets are respectively provided with staggered holes I at positions outside the bottom of the winding slot A. The projections of two adjacent staggered holes I along the direction parallel to the center line of the rotating shaft overlap. All staggered holes I are connected in sequence to form oil channel I. All stator punching sheets are respectively provided with staggered holes II at positions between two adjacent winding slots A. The projections of two adjacent staggered holes II along the direction parallel to the center line of the rotating shaft overlap. All staggered holes II are connected in sequence to form oil channel II.

3. A high power density motor cooling structure according to claim 2, characterized in that: Oil guide grooves respectively connected with the oil passage II and the oil inlet chamber are provided on both side surfaces of the stator oil separator ring and correspond to the positions of the oil passage II respectively. The projection of the oil passage II along the center line of the rotating shaft is located within the projection of the oil guide groove along the center line of the rotating shaft.

4. A high power density motor cooling structure according to claim 1, characterized in that: A stator oil injection ring which is arranged coaxially with the rotating shaft is arranged in the casing and at positions respectively located outside the two stator cores. The stator oil injection ring is fixedly and sealedly connected to the inner surface of the casing. An oil injection groove which is coaxially with the stator oil injection ring is recessed on a side surface of the stator oil injection ring facing one side of the stator core. The stator oil injection ring is fixedly and sealedly connected to an outer side surface of the stator core corresponding to the side on which it is located. An oil injection cavity is formed between the oil injection groove and the stator core corresponding to the side on which it is located. Connecting holes extending in a direction parallel to the center line of the stator core are evenly spaced around the center line direction of the stator core. The connecting holes form an oil passage III. The two ends of the oil passage III are respectively connected to the oil injection cavity and the oil inlet chamber. A plurality of oil injection holes extending in a radial direction of the rotating shaft and connected to the oil injection cavity are evenly spaced around the center line direction of the stator oil injection ring on the inner side surface.

5. The high power density motor cooling structure according to claim 1, characterized in that: The shaft body of the rotating shaft located on the inner side of the rotor core is provided with a plurality of oil-slinging holes II at evenly spaced intervals around the center line direction of the rotating shaft, the oil-slinging holes II extend along the radial direction of the rotating shaft and are connected with the closed chamber, the shaft body of the rotating shaft is provided with an oil guide groove located at the outer opening position of the oil-slinging hole II along the direction parallel to the center line direction of the rotating shaft, one end of the oil guide groove is connected with the corresponding oil-slinging hole II, and the other end extends in the direction opposite to the rotor oil-slinging ring and extends out of the rotor core on its side.

6. A high power density motor cooling structure according to claim 1, characterized in that: An oil inlet pipe coaxial with the rotating shaft is provided at one end of the rotating shaft located at the oil delivery port, an oil outlet end of the oil inlet pipe passes through the oil delivery port and extends into the closed chamber, the oil inlet pipe is spaced apart from an inner wall of the oil delivery port, and a sealing ring that can respectively seal with the oil inlet pipe and the oil delivery port is sleeved on the pipe body of the oil inlet pipe located between the oil inlet pipe and the oil delivery port.

7. A high power density motor cooling structure according to claim 5, characterized in that: The size of the oil-slinging hole I is larger than that of the oil-slinging hole II.

8. A cooling method for a high power density motor cooling structure, characterized in that: The cooling method is applied to a high power density motor cooling structure as described in claim 1, and the cooling method for the motor cooling structure comprises: cooling oil enters the oil inlet chamber through two oil inlets respectively, is divided into three oil channels through the oil inlet chamber, and flows into multiple oil inlet channels respectively. When the cooling oil flows through the oil inlet channel, it will take away the heat of the stator core and the heat transferred by the winding cable in the winding wire slot A, and cool the winding cable and the stator core. After cooling, the cooling oil is concentrated in the cooling chamber and discharged through the oil outlet; At the same time, the cooling oil enters the closed chamber of the rotating shaft through the oil delivery port. Under the action of external oil pressure and centrifugal force, the cooling oil flows into the annular groove of the rotor oil-slinging ring when passing through the oil-slinging hole Ⅰ of the rotating shaft. An oil-slinging chamber is formed between the annular groove and the rotating shaft. The cooling oil then enters the cooling oil hole through the connecting hole A and the connecting hole B through the oil-slinging chamber to cool the squirrel cage winding. The cooled cooling oil is collected in the cooling chamber through the cooling oil hole and then discharged from the oil drain port.

9. The cooling method of a high power density motor cooling structure according to claim 8, characterized in that: When the cooling oil flows through the oil channel I, it will take away the heat of the stator core and the heat transferred by the winding cable on the outside of the bottom of the winding slot A, and cool the winding cable and the stator core; when the cooling oil flows through the oil channel II, it will take away the heat of the stator core and the heat transferred by the winding cable between the two winding slots A, and cool the winding cable and the stator core. When the cooling oil flows through the oil channel III, the oil channel III introduces the cooling oil into the injection cavity of the stator injection ring. Under the action of the external oil pressure, the cooling oil in the injection cavity is sprayed to the end position of the winding cable through the injection hole, and the end position of the winding cable and the stator core are cooled; After cooling, the cooling oil in the oil passages I, II and III is concentrated in the cooling chamber and discharged through the oil drain port.

10. The cooling method of a high power density motor cooling structure according to claim 8, characterized in that: The cooling oil enters the closed chamber of the rotating shaft through the oil delivery port. Under the action of external oil pressure and centrifugal force, the cooling oil in the closed chamber will enter the oil inlet groove through the oil throwing hole Ⅱ of the rotating shaft. The oil inlet groove will introduce the cooling oil to the outer end of the rotor core. After cooling, the cooling oil flows into the cooling chamber and is discharged from the oil drain port.

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