A motor rotor cooling oil circuit structure

Abstract

A motor rotor cooling oil circuit structure relates to the cooling of a permanent magnet synchronous motor, comprising a hollow shaft sleeve, on which a first oil inlet hole is provided; an oil guide plate, sleeved on the hollow shaft sleeve; a first channel communicated with the oil inlet hole is provided on the oil guide plate; a magnetic cake, fitted with the oil guide plate and sleeved on the hollow shaft sleeve; a second channel communicated with the first channel is provided on the magnetic cake; and a magnetic isolation plate, fitted with the magnetic cake and sleeved on the hollow shaft sleeve; an oil outlet channel communicated with the second channel is provided on the magnetic isolation plate; the present invention introduces cooling oil into the magnetic cake through the first oil inlet hole of the hollow shaft sleeve and the oil delivery channel of the oil guide plate to cool the magnetic cake, and then flows into the annular oil groove of the magnetic isolation plate, thereby achieving effective cooling of the rotor.

Description

Technical Field

[0001] The invention relates to the cooling of a permanent magnet synchronous motor, and in particular to a motor rotor cooling oil circuit structure. Background Art

[0002] At present, there are various types of permanent magnet synchronous motors in the new energy field, and their core parts are generally concentric structures of stators and rotors. After power is turned on, the electric energy in the stator coil drives the rotor equipped with permanent magnet materials to rotate through the magnetic field. In this process, a large amount of heat energy will be generated. In order to ensure the performance and service life of the motor, the core components in the motor need to be cooled in time.

[0003] There are many hybrid vehicles on the market that integrate the motor into the gearbox, which can effectively solve the heat dissipation problem of the stator. However, the cooling solution of the rotor, especially the effective cooling of the rotor magnetic disk and rotor bearings, still faces various difficulties. Summary of the invention

[0004] In view of the above problems, the present invention proposes a new oil circuit structure for cooling the rotor to achieve effective cooling of the internal structure of the rotor.

[0005] The technical solution proposed by the present invention is as follows:

[0006] A motor rotor cooling oil circuit structure includes a hollow shaft sleeve, which is provided with a first oil inlet hole; an oil guide plate, which is sleeved on the hollow shaft sleeve; the oil guide plate is provided with a first channel connected to the oil inlet hole; a magnetic cake, which is fitted with the oil guide plate and sleeved on the hollow shaft sleeve; the magnetic cake is provided with a second channel connected to the first channel; and two magnetic isolation plates, which are sleeved on the hollow shaft sleeve; the oil guide plate and the magnetic cake are arranged between the two magnetic isolation plates; the magnetic isolation plate of the two magnetic isolation plates, which is fitted with the magnetic cake, is provided with an oil outlet channel connected to the second channel.

[0007] Furthermore, the magnetic cake includes an upper magnetic cake and a lower magnetic cake, and the upper magnetic cake and the lower magnetic cake are symmetrically arranged on both sides of the oil guide plate, and the upper magnetic cake and the lower magnetic cake are respectively corresponding to and fitted with the upper end surface and the lower end surface of the oil guide plate; the two magnetic isolation plates are respectively arranged on the end surfaces of the upper magnetic cake and the lower magnetic cake away from the oil guide plate.

[0008] Furthermore, the oil guide plate includes a first oil guide plate and a second oil guide plate, and the first oil guide plate is provided with

[0009] A first notch communicates with the central hole of the first oil guide plate and extends along the radial direction of the first oil guide plate;

[0010] A second notch is provided on the plate surface of the first oil guide plate and penetrates the plate surface;

[0011] a first opening, close to the second notch; the first opening is provided on the plate surface of the first oil guide plate and penetrates the plate surface, there are a plurality of the first openings, and the plurality of the first openings are arranged along the radial direction of the first oil guide plate; and

[0012] a second opening, away from the second notch and close to the first notch, the second opening being arranged on the plate surface of the first oil guide plate and penetrating the plate surface, the second opening being multiple, and the multiple second openings being arranged along the radial direction of the first oil guide plate;

[0013] The second oil guide plate has the same structure as the first oil guide plate;

[0014] The first oil guide plate and the second oil guide plate are fitted together, so that the first notch on the first oil guide plate is communicated with the second notch on the second oil guide plate, the second notch on the second oil guide plate is communicated with the second opening on the first oil guide plate, and the second opening on the first oil guide plate is communicated with the first opening on the first oil guide plate, thereby forming an oil guide plate with a first channel.

[0015] Furthermore, there are a plurality of the first channels, and the plurality of the first channels are distributed on the oil guide plate at equal angles around the axis of the oil guide plate.

[0016] Furthermore, the outer circumferential surfaces of the first oil guide plate and the second oil guide plate are both provided with anti-misinstallation marking grooves.

[0017] Furthermore, the upper magnetic cake and the lower magnetic cake are both provided with through oil holes, and the oil holes on the upper magnetic cake and the lower magnetic cake constitute the second channel.

[0018] Furthermore, an annular oil groove is provided at one end of the magnetic isolation plate facing the magnetic cake; the annular oil groove is provided with a plurality of oil-throwing ports connected thereto, and the plurality of oil-throwing ports are circumferentially distributed on the annular oil groove; the annular oil groove and the plurality of oil-throwing ports together constitute the oil outlet channel.

[0019] Furthermore, a second oil inlet for cooling the bearing is provided at the sleeve opening of the hollow sleeve.

[0020] Furthermore, the axis of the second oil inlet intersects with the axis of the hollow sleeve and forms an inclination angle α, wherein 75°≥α≥45°.

[0021] The beneficial effects achieved by adopting this technical solution are:

[0022] 1. The present invention introduces cooling oil into the magnetic cake through the first oil inlet hole of the hollow shaft sleeve and the oil delivery channel of the oil guide plate to cool the magnetic cake, and then flows into the annular oil groove of the magnetic isolation plate, thereby achieving effective cooling of the rotor.

[0023] 2. The cooling oil passage provided by the present invention, especially the staggered oil passage formed on the oil guide plate, can effectively avoid the adverse effects such as uneven cooling caused by excessive injection of cooling oil, affecting the rotor performance output and even eccentricity, and meet the requirements of high efficiency and lightweight of the motor.

[0024] 3. The bearing is directly sprayed and cooled through the second oil hole at the sleeve mouth of the hollow shaft sleeve, which reduces the risk of high-temperature demagnetization of the bearing magnetic steel, improves the cooling effect of the bearing, and thus improves the performance and service life of the motor rotor under long-term high-load operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is an exploded view of the rotor structure of the present invention.

[0026] Figure 2 This is the assembly diagram of the rotor structure.

[0027] Figure 3 for Figure 2 The cross-section view of section AA shows the internal structure of the rotor.

[0028] Figure 4 This is a diagram of the magnetic cake structure.

[0029] Figure 5 This is a structural diagram of the magnetic isolation plate.

[0030] Figure 6 This is the exploded structure diagram of the oil guide plate.

[0031] Figure 7 This is the structural diagram of the assembled oil guide plate.

[0032] Figure 8 for Figure 7 The partial enlarged view at point B shows the flow direction of the cooling oil in the first channel.

[0033] Fig. 9 for Figure 3 The partial enlarged view of point C in the middle shows the structural layout of the second oil inlet hole.

[0034] Among them: 10 hollow shaft sleeve, 11 first oil inlet hole, 12 second oil inlet hole, 20 oil guide plate, 21 first oil guide plate, 22 second oil guide plate, 23 anti-wrong installation identification groove, 30 magnetic cake, 31 upper magnetic cake, 32 lower magnetic cake, 33 oil hole, 34 weight reduction groove, 40 magnetic isolation plate, 41 annular oil groove, 42 oil throwing port, 211 first notch, 212 second notch, 213 first opening, 214 second opening. DETAILED DESCRIPTION

[0035] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0036] In a specific embodiment of the present invention, a motor rotor cooling oil circuit structure is proposed, and the cooling oil circuit structure is composed of a plurality of components; see Figure 1-Figure 3 Specifically, the components include a hollow shaft sleeve 10, an oil guide plate 20, a magnetic cake 30 and two magnetic isolation plates 40.

[0037] Specifically, the oil guide plate 20, the magnetic cake 30 and the magnetic isolation plate 40 are all sleeved on the hollow shaft sleeve 10; and a first oil inlet hole 11 is provided on the hollow shaft sleeve 10, and a first channel communicating with the first oil inlet hole 11 is provided on the oil guide plate 20; the magnetic cake 30 is fitted with the oil guide plate 20 and a second channel communicating with the first channel is provided on the magnetic cake 30; the oil guide plate 20 and the magnetic cake 30 are arranged between two magnetic isolation plates 40, and an oil outlet channel communicating with the second channel is provided on the magnetic isolation plate 40 fitted with the magnetic cake 30.

[0038] In specific use, the hollow sleeve 10 is sleeved on a rotating shaft (not shown), an oil passage is provided in the rotating shaft, and an oil outlet hole is provided on the rotating shaft, which corresponds to the first oil inlet hole 11 of the hollow sleeve 10 .

[0039] As the rotor starts to rotate, cooling oil is supplied to the shaft. Under the action of centrifugal force, the cooling oil enters the first oil inlet hole 11 in the hollow sleeve 10 from the oil outlet hole on the shaft, and then flows into the first channel and the second channel in sequence, and finally is discharged through the oil outlet channel.

[0040] When the cooling oil passes through the second oil passage, due to the effect of centrifugal force, the cooling oil can be dispersedly distributed to the upper and lower surfaces of the magnetic cake 30, thereby achieving an effective cooling effect on the magnetic cake 30.

[0041] In an embodiment of the present invention, the magnetic disk 30 of the rotor includes an upper magnetic disk 31 and a lower magnetic disk 32 of the same structure, and both the upper magnetic disk 31 and the lower magnetic disk 32 are provided with a through oil hole 33, and the oil holes 33 on the upper magnetic disk 31 and the lower magnetic disk 32 constitute the second channel.

[0042] The oil guide plate 20 is arranged between the upper magnetic cake 31 and the lower magnetic cake 32; it can be understood that: the upper magnetic cake 31 and the lower magnetic cake 32 are symmetrically arranged on both sides of the oil guide plate 20, and the upper magnetic cake 31 and the lower magnetic cake 32 should respectively fit with the upper end surface and the lower end surface of the oil guide plate 20, and the smooth connection between the first channel and the second channel is ensured by mutual fitting.

[0043] Here, the magnetic cake 30 is divided into an upper and lower magnetic cake and arranged at both ends of the oil guide plate 20 to ensure the balanced cooling of the cooling oil on the magnetic cake 30. When the cooling oil is about to enter the second channel during the rotation process of the rotor, it can be dispersed toward the magnetic cakes 30 at both ends of the oil guide plate 20 at the same time, that is, the cooling oil flows upward and downward at the same time, thereby improving the cooling effect on the magnetic cake 30.

[0044] In a specific embodiment of the present invention, see Figure 1 , Figure 4 , the upper magnetic cakes 31 and the lower magnetic cakes 32 are provided in plurality, that is, a plurality of upper magnetic cakes 31 are stacked on the upper end surface of the oil guide plate 20, and a plurality of lower magnetic cakes 32 are stacked on the lower end surface of the oil guide plate 20. The plurality of upper magnetic cakes 31 and the plurality of lower magnetic cakes 32 are stacked on each other. Compared with the traditional design in which the magnetic cakes are made into an integrated structure and the cooling oil can only cool the parts around the oil holes 33, the plurality of stacked magnetic cakes allow part of the cooling oil to penetrate the gaps between the magnetic cakes to effectively cool each magnetic cake, so that the cooling oil can finally cool the inside of the magnetic cake, thereby improving the cooling effect of the cooling oil on the magnetic cake.

[0045] Preferably, in order to ensure that the total thickness of the rotor is consistent with the total thickness of the stator, in a specific embodiment of the present invention, two upper magnetic discs 31 are arranged on the upper end surface of the oil guide plate 20, and two lower magnetic discs 32 are arranged on the lower end surface of the oil guide plate 20.

[0046] Preferably, each upper magnetic disk 31 and lower magnetic disk 32 is also provided with a weight reduction groove 34 for reducing weight. It should be noted that, under the premise of ensuring strength, cooling oil should be prevented from flowing into the weight reduction hole to affect the rotor performance.

[0047] The cooling oil passing through the second channel will eventually be discharged through the oil outlet channel under the action of centrifugal force. The oil outlet channel is arranged on the magnetic isolation plate 40 .

[0048] For details, see Figure 1-Figure 3 , Figure 4 , the magnetic isolation plate 40 is attached to the end surface of the magnetic cake 30 to achieve effective isolation of the magnetic field; in the specific embodiment of the present invention, because the magnetic cake 30 is divided into an upper magnetic cake 31 and a lower magnetic cake 32, the cooling oil will be diverted to flow to the upper magnetic cake 31 and the lower magnetic cake 32, so the magnetic isolation plate 40 is respectively arranged on the upper end surface of the upper magnetic cake 31 and the lower end surface of the lower magnetic cake 32.

[0049] The oil outlet passage is composed of the annular oil groove 41 and the oil outlet 42 provided on the magnetic isolation plate 40. For details, see Figure 1-Figure 3 , Figure 5The annular oil groove 41 is arranged on one end of the magnetic isolation plate 40 facing the magnetic cake 30; and in order to ensure that the cooling oil flowing out of the second channel can smoothly enter the annular oil groove 41, the position of the annular oil groove 41 should correspond to the oil through hole 33; and the cross-sectional width of the annular oil groove 41 should be larger than the aperture of the oil through hole 33 to ensure that the cooling oil can smoothly flow into the annular oil groove 41; and the oil throwing port 42 is connected to the annular oil groove 41 and is distributed in a ring along the annular oil groove 41. Under the action of centrifugal force, the cooling oil entering the annular oil groove 41 will be discharged through the oil throwing port 42.

[0050] In the prior art, how to guide the cooling oil from the first oil inlet hole 11 on the hollow sleeve 10 to the oil through hole 33 on the magnetic cake to achieve cooling of the magnetic cake is a design point that is difficult to grasp. Therefore, in this embodiment, an oil guide plate 20 with a new structure is proposed to realize the formation of the first channel to ensure that the cooling oil flowing to the second channel can effectively and stably cool the magnetic cake.

[0051] See also Figure 1 , Figure 6-Figure 7 The oil guide plate 20 is arranged between the magnetic cakes 30. In order to minimize the influence of the oil guide plate 20 on the thickness of the entire rotor, the oil guide plate 20 proposed in this embodiment is composed of two thin sheets with the same structure. The thickness of each thin sheet is about 1 mm, so that the thickness of the formed oil guide plate 20 is maintained at about 2 mm; and the use of two thin sheets with the same structure is not only conducive to the formation of the first channel, but also convenient for the processing and manufacturing of the mold, thereby achieving the purpose of saving costs.

[0052] For ease of understanding and description, the two thin sheets are named the first oil guide plate 21 and the second oil guide plate 22 respectively. Since the first oil guide plate 21 and the second oil guide plate 22 have the same structure, in this embodiment, as long as the structure of the first oil guide plate 21 is described, it is equivalent to describing the structure of the second oil guide plate 22 at the same time.

[0053] The first oil guide plate 21 is sleeved on the hollow shaft sleeve 10, so a center hole is provided on the first oil guide plate 21, and the first oil guide plate 21 is coaxially arranged with the hollow shaft sleeve 10 through the center hole; a first notch 211, a second notch 212, a first opening 213 and a second opening 214 are also provided on the first oil guide plate 21; similarly, a first notch 211, a second notch 212, a first opening 213 and a second opening 214 are also provided on the second oil guide plate 22; the two oil guide plates fit each other, so that the first notch 211, the second notch 212, the first opening 213 and the second opening 214 on the first oil guide plate 21 and the second oil guide plate 22 cooperate with each other to form a first channel with a staggered structure.

[0054] Specifically, the first notch 211 is communicated with the central hole of the first oil guide plate 21 and extends in the radial direction of the first oil guide plate 21; the second notch 212 is provided on the plate surface of the first oil guide plate 21 and penetrates the plate surface; the first slot 213 is close to the second notch 212 and also penetrates the plate surface of the first oil guide plate 21; and there are multiple first slots 213, and the multiple first slots 213 are arranged in the radial direction of the first oil guide plate 21; the second slot 214 is far away from the second notch 212 and close to the first notch 211, the second slot 214 penetrates the plate surface of the first oil guide plate 21 and there are multiple second slots 214, and the multiple second slots 214 are arranged in the radial direction of the first oil guide plate 21; when the first oil guide plate 21 and the second oil guide plate 22 are fitted with each other, the notch and slot on the first oil guide plate 21 will cooperate with the notch and slot on the second oil guide plate 22 to form a first channel.

[0055] The specific formation method is: the first oil guide plate 21 and the second oil guide plate 22 are attached to each other front and back; the front and back attachment here means that the front side of the first oil guide plate 21 and the front side of the second oil guide plate 22 are attached to each other, that is, the front side is attached to the front side, and the back side is attached to the back side.

[0056] See also Figure 6-Figure 8 After the bonding is completed, the first notch 211 on the first oil guide plate 21 corresponds to and communicates with the second notch 212 on the second oil guide plate 22; at the same time, the second notch 212 on the second oil guide plate 22 corresponds to and communicates with the second opening 214 on the first oil guide plate 21; the second opening 214 on the first oil guide plate 21 corresponds to and communicates with the first opening 213 on the second oil guide plate 22, so that the first channel finally formed is not straight, but the internal structure is staggered. The staggered structure here can make the cooling water flow in the first channel in a wave-like swinging manner until it flows into the second channel formed by the magnetic cake 30 (the direction of the arrow in the figure is the wave-like flow direction of the cooling oil formed due to the staggered structure of the first channel).

[0057] It should be noted that the first channel here cannot be set in a straight-through form. The so-called straight-through form can be understood as opening a strip groove on the first oil guide plate 21 and opening a strip groove on the second oil guide plate 22. When the first oil guide plate 21 and the second oil guide plate are fitted together, the two strip grooves are combined into a straight-through channel. The use of a straight-through channel will result in a large amount of cooling oil being accumulated at the interface between the first channel and the second channel due to the action of centrifugal force when the rotor rotates at high speed, and the stable flow of the cooling oil cannot be achieved, which will not only seriously affect the discharge of the cooling oil, but also cause the uneven distribution of the cooling oil, resulting in poor performance output of the rotor and even eccentricity.

[0058] Therefore, in a specific embodiment of the present invention, by designing the structure of the oil guide plate 20, the first channel finally formed has a staggered structure, so that the cooling oil is continuously guided to change the flow direction in the first channel, avoiding the problem of cooling oil accumulation during centrifugal movement, and effectively promoting the stability and balance of the cooling oil flow in the first channel.

[0059] Preferably, there are multiple first channels as described above, and the multiple first channels are distributed on the oil guide plate 20 at equal angles around the axis of the oil guide plate 20. Of course, correspondingly, the second channels in the magnetic cake 30 should be the same in number as the first channels and correspond to each other.

[0060] Preferably, considering that the first oil guide plate 21 and the second oil guide plate 22 have the same structure, to avoid wrong installation by the installer during assembly, anti-wrong installation identification grooves 23 are provided on the outer circumferential surfaces of the first oil guide plate 21 and the second oil guide plate 22.

[0061] Preferably, considering that when the rotor rotates at a high speed, the rotor bearing (not shown) also faces the problem of needing heat dissipation, the rotor bearing sleeve is arranged at the sleeve opening of the hollow shaft sleeve 10, therefore, see Fig. 9 A second oil inlet hole 12 for cooling the bearing is provided at the sleeve opening of the hollow shaft sleeve 10.

[0062] In a specific embodiment of the present invention, the second oil inlet hole 12 is arranged at an angle. For ease of understanding, the second oil inlet hole 12 is defined here to include an oil inlet end and an oil outlet end, and the oil outlet end is close to the rotor bearing. The inclined arrangement essentially means that the oil outlet end of the second oil inlet hole 12 is directly opposite to the steel balls in the rotor bearing, so that the cooling oil is sprayed obliquely from the second oil inlet hole 12; when the rotor rotates, the cooling oil passes through the second oil inlet hole 12 and is sprayed on the steel balls of the rotor bearing, which not only cools the steel balls, but also the rotation of the steel balls causes the cooling oil to adhere to the magnetic steel of the bearing, thereby achieving the purpose of cooling the magnetic steel.

[0063] Preferably, the axis of the second oil inlet hole 12 intersects with the axis of the hollow sleeve 10 and forms an inclination angle α, wherein 75°≥α≥45°. In a specific test operation, when the angle α is 60°, the cooling effect on the steel ball is best.

[0064] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A motor rotor cooling oil circuit structure, characterized in that: The invention comprises a hollow shaft sleeve (10) on which a first oil inlet hole (11) is provided; an oil guide plate (20) sleeved on the hollow shaft sleeve (10); the oil guide plate (20) is provided with a first channel which is in communication with the first oil inlet hole (11) and has a staggered structure; A magnetic cake (30) is fitted with the oil guide plate (20) and sleeved on the hollow shaft sleeve (10); a second channel communicating with the first channel is provided on the magnetic cake (30); and two magnetic isolation plates (40) are sleeved on the hollow shaft sleeve (10); the oil guide plate (20) and the magnetic cake (30) are arranged between the two magnetic isolation plates (40); the magnetic isolation plate (40) fitted with the magnetic cake (30) is provided with an oil outlet channel communicating with the second channel; the oil guide plate (20) comprises a first oil guide plate (21) and a second oil guide plate (22); the first oil guide plate (21) is provided with a first notch (211) communicating with the center hole of the first oil guide plate (21) and extending in the radial direction of the first oil guide plate (21); a second notch (212) is provided on the plate surface of the first oil guide plate (21) and passes through the plate surface; a first opening (213), close to the second notch (212); the first opening (213) is arranged on the plate surface of the first oil guide plate (21) and penetrates the plate surface, there are a plurality of the first openings (213), and the plurality of the first openings (213) are arranged along the radial direction of the first oil guide plate (21); and a second opening (214), away from the second notch (212) and close to the first notch (211), the second opening (214) is arranged on the plate surface of the first oil guide plate (21) and penetrates the plate surface, there are a plurality of the second openings (214), and the plurality of the second openings (214) are arranged along the radial direction of the first oil guide plate (21); the second oil guide plate (22) has the same structure as the first oil guide plate (21); The first oil guide plate (21) and the second oil guide plate (22) are fitted together so that the first notch (211) on the first oil guide plate (21) is communicated with the second notch (212) on the second oil guide plate (22), the second notch (212) on the second oil guide plate (22) is communicated with the second opening (214) on the first oil guide plate (21), and the second opening (214) on the first oil guide plate (21) is communicated with the first opening (213) on the second oil guide plate (22), thereby forming An oil guide plate (20) with a first channel; the magnetic cake (30) comprises an upper magnetic cake (31) and a lower magnetic cake (32), the upper magnetic cake (31) and the lower magnetic cake (32) are symmetrically arranged on both sides of the oil guide plate (20), and the upper magnetic cake (31) and the lower magnetic cake (32) are respectively correspondingly fitted with the upper end surface and the lower end surface of the oil guide plate (20); the two magnetic isolation plates (40) are respectively arranged on the end surfaces of the upper magnetic cake (31) and the lower magnetic cake (32) away from the oil guide plate (20).

2. The motor rotor cooling oil circuit structure according to claim 1, characterized in that: The upper magnetic cake (31) and the lower magnetic cake (32) are both provided with a through oil hole (33), and the oil holes (33) on the upper magnetic cake (31) and the lower magnetic cake (32) constitute the second channel.

3. The motor rotor cooling oil circuit structure according to claim 1, characterized in that: There are a plurality of the first channels, and the plurality of the first channels are distributed on the oil guide plate (20) at equal angles around the axis of the oil guide plate (20).

4. The motor rotor cooling oil circuit structure according to claim 1, characterized in that: Anti-mis-installation marking grooves (23) are provided on the outer circumferential surfaces of the first oil guide plate (21) and the second oil guide plate (22).

5. The motor rotor cooling oil circuit structure according to claim 1, characterized in that: An annular oil groove (41) is provided at one end of the magnetic isolation plate (40) facing the magnetic cake (30); the annular oil groove (41) is provided with a plurality of oil-throwing ports (42) communicating therewith, and the plurality of oil-throwing ports (42) are circumferentially distributed on the annular oil groove (41); the annular oil groove (41) and the plurality of oil-throwing ports (42) together constitute the oil outlet channel.

6. The motor rotor cooling oil circuit structure according to claim 1, characterized in that: A second oil inlet hole (12) for cooling the bearing is provided at the sleeve opening of the hollow shaft sleeve (10).

7. The motor rotor cooling oil circuit structure according to claim 6, characterized in that: The axis of the second oil inlet hole (12) intersects with the axis of the hollow shaft sleeve (10) and forms an inclination angle α, wherein 75°≥α≥45°.

Images