Oil pump for pure electric power system assembly

Abstract

The utility model discloses an oil pump for a pure electric power system assembly, which comprises an oil pump shell consisting of an oil pump main shell and an oil pump cover body, the oil pump main shell is arranged on the inner side wall of a transmission support plate, an inner rotor and an outer rotor which are eccentrically arranged are arranged in the oil pump main shell, and the inner rotor is meshed with the outer rotor. The end of the inner rotor shaft penetrates through the inner rotor and then extends out of the oil pump shell to be connected with an oil pump driven gear, the oil pump driven gear is meshed with an oil pump driving gear, the oil pump driving gear is installed on a transmission intermediate shaft, the outer rotor is provided with n + 1 inner teeth, the inner rotor is provided with n outer teeth, and the inner teeth and the outer teeth are in a cycloid tooth shape. According to the design, the fault that oil liquid of the oil pump leaks to the outside under the severe working condition can be avoided, the oil pump is small in size, large in displacement, good in dynamic balance, small in operation vibration and low in noise, and the lubricating requirement is met.

Description

TECHNICAL FIELD

[0001] The utility model belongs to oil pump technical field relates to an oil pump assembly, concretely relates to an oil pump for pure electric power system assembly. BACKGROUND

[0002] With the development of new energy pure electric mine car, the pure electric power system mine car has been sold more than hundreds of sets in mine car market, the market of pure electric mine car will continue to grow in the future, based on environmental protection, artificial cost and other factors, more and more pure electric mine car customer's demand tends to high load, high reliability, can be loaded uphill, gear shifting power interruption and unmanned.

[0003] The existing pure electric mine car under no load, if the running mode is changed to the mode of many pull fast running, will lead to pure electric power system to be in overspeed operation, that is, the motor speed and the transmission speed are all in the highest state, the oil pump input speed is increased, which will cause the whole vehicle to vibrate greatly, and the oil leakage of the external gear pump of the transmission will be easily caused to the outside, in order to avoid the oil leakage, the oil pump is sealed, which will increase the complexity of the oil pump, increase the weight of the oil pump and increase the manufacturing cost.

[0004] When the pure electric mine car is loaded uphill, the transmission is always in low gear overload operation, at this time, the forced lubrication provided by the oil pump is very important for the operation of the transmission, once the lubrication is insufficient, the transmission will cause serious failure such as gear pitting and bearing ablation. SUMMARY

[0005] In view of the deficiencies in the prior art, the utility model aims at providing an oil pump for pure electric power system assembly, which can solve the technical problems of oil leakage of external oil pump in existing pure electric power system and functional failure of transmission caused by insufficient lubrication of oil pump when transmission is in low gear overload operation.

[0006] In order to solve the above technical problems, the utility model adopts the following technical scheme to realize it:

[0007] An oil pump for pure electric power system assembly, comprising an oil pump housing mounted on a transmission support plate, characterized in that the oil pump housing comprises an oil pump main housing and an oil pump cover body, the axial rear end surface of the oil pump main housing is detachably mounted on the inner side wall of the transmission support plate, the axial rear end surface of the oil pump cover body is detachably mounted on the axial front end surface of the oil pump main housing, and an inner rotor shaft, an inner rotor and an outer rotor are installed in the oil pump housing.

[0008] The axial front end surface of the oil pump main shell is provided with a large circular groove, the bottom of the large circular groove is provided with a stepped blind hole, the large circular groove and the stepped blind hole are eccentrically arranged, the bottom of the large circular groove is provided with a crescent-shaped first oil inlet groove and a crescent-shaped first oil outlet groove, and the first oil inlet groove and the first oil outlet groove are symmetrically arranged.

[0009] The inner rotor is arranged in the outer rotor and is eccentrically arranged with the outer rotor and engaged with the outer rotor, the outer rotor is arranged in the large circular groove, the outer diameter of the outer rotor is matched with the inner diameter of the large circular groove, one end of the inner rotor shaft is arranged in the stepped blind hole, the other end of the inner rotor shaft sequentially passes through the inner rotor and the stepped through hole and extends out of the oil pump cover body to be connected with an oil pump driven gear, the inner rotor and the oil pump driven gear are fixedly installed on the inner rotor shaft through connecting pieces, the oil pump driven gear is engaged with an oil pump driving gear, and the oil pump driving gear is installed on a transmission intermediate shaft.

[0010] The utility model also includes the following technical features:

[0011] The outer rotor is provided with n+1 inner teeth, the inner rotor is provided with n outer teeth, the tooth profile of the inner teeth and the outer teeth is all cycloid tooth profile, and the eccentric distance between the outer rotor and the inner rotor is e.

[0012] The eccentric distance between the large circular groove and the stepped blind hole is same with the eccentric distance between the outer rotor and the inner rotor.

[0013] The number of teeth of the oil pump driving gear is greater than the number of teeth of the oil pump driven gear, and the speed ratio of the oil pump driving gear and the oil pump driven gear is less than 1.

[0014] The axial rear end surface of the oil pump cover body is provided with a crescent-shaped second oil inlet groove and a crescent-shaped second oil outlet groove, and the second oil inlet groove and the second oil outlet groove are correspondingly arranged with the first oil inlet groove and the first oil outlet groove.

[0015] The space surrounded by the first oil inlet groove, the first oil outlet groove, the second oil inlet groove, the second oil outlet groove, the inner teeth and the outer teeth is a pump oil working space.

[0016] The transmission support plate is provided with an oil pump first oil inlet channel and an oil pump oil outlet channel, the oil pump main shell is fixedly connected with an oil inlet shell, the oil inlet shell is provided with an oil pump second oil inlet channel, one end of the oil pump second oil inlet channel is connected with the oil pump first oil inlet channel through an oil pump oil inlet port, the other end of the oil pump second oil inlet channel is connected with the first oil inlet groove, and the first oil outlet groove is connected with the oil pump oil outlet channel through an oil pump oil outlet port.

[0017] The axial front end surface of the oil pump main shell is provided with an annular groove coaxially arranged with the large circular groove, and the annular groove is provided with a sealing ring.

[0018] The inner rotor shaft is provided with a first shaft shoulder and a second shaft shoulder, the first shaft shoulder is arranged on the axial front end surface of the inner rotor, the second shaft shoulder is arranged on the axial rear end surface of the oil pump driven gear, and the inner rotor shaft is further sleeved with a first steel wire baffle and a second steel wire baffle, the first steel wire baffle is located on the axial rear end surface of the inner rotor, and the second steel wire baffle is located on the axial front end surface of the oil pump driven gear.

[0019] The first support member is arranged in the stepped blind hole, and the second support member is arranged in the stepped through hole.

[0020] The first support member and the second support member are needle bearings or sliding bearings.

[0021] The inner wall of the stepped blind hole and the inner wall of the stepped through hole are both provided with an oil guide groove in the axial direction.

[0022] Compared with the prior art, the utility model has the following technical effects:

[0023] In the utility model, the oil pump is installed in the transmission, so that the oil leakage of the oil pump to the outside under the harsh working conditions of high rotation speed and high vibration is avoided; the cycloid rotor structure of the inner rotor and the outer rotor is combined with the bearing support at the two ends of the inner rotor shaft, so that the good balance of the oil pump is ensured, the vibration is small during operation, the noise is low, and the super high speed working condition of the pure electric power system assembly is more suitable; the speed ratio of the oil pump driving gear and the oil pump driven gear is less than 1, the high efficiency advantage of the cycloid rotor structure is combined, the larger displacement of the oil pump under the lower rotation speed is realized, the lubrication demand of the transmission under the overload working condition of the low gear is met, meanwhile, the volume occupied by the oil pump under the certain displacement is smaller, the size of the oil pump is smaller, and the arrangement of the oil pump in the transmission is easier to realize. BRIEF DESCRIPTION OF DRAWINGS

[0024] Fig. 1 It is the structure section view of the utility model.

[0025] Fig. 2 It is the external structure schematic view of the utility model.

[0026] Fig. 3 It is the internal structure schematic view of the oil pump shell of the utility model.

[0027] The meanings of the various reference numerals in the drawings are as follows:

[0028] 1. Transmission support plate; 2. Oil pump housing; 3. Inner rotor shaft; 4. Inner rotor; 5. Outer rotor; 6. Oil pump driven gear; 7. Connecting piece; 8. Oil pump drive gear; 9. Transmission intermediate shaft; 10. Oil pump first inlet channel; 11. Oil pump outlet channel; 12. Oil pump inlet; 13. Oil pump outlet; 14. Sealing ring; 15. First shoulder; 16. Second shoulder; 17. First wire retaining ring; 18. Second wire retaining ring; 19. First support piece; 20. Second support piece.

[0029] 21. Oil pump main housing; 22. Oil pump cover; 23. Oil inlet housing; 24. Oil pump second oil inlet channel;

[0030] 211. Large circular groove; 212. Stepped blind hole; 213. First oil inlet groove; 214. Second oil outlet groove; 221. Stepped through hole.

[0031] The specific content of this utility model will be further explained in detail below with reference to the embodiments. Detailed Implementation

[0032] Following the above technical solution, the following are specific embodiments of this utility model. It should be noted that this utility model is not limited to the following specific embodiments, and all equivalent modifications made based on the technical solution of this application fall within the protection scope of this utility model.

[0033] In this utility model, unless otherwise stated, directional terms such as "upper", "lower", "left", "right", "front end", and "rear end" are generally defined based on the drawing in the corresponding figure, and "inner" and "outer" refer to the inner and outer contours of the corresponding components.

[0034] Example:

[0035] This embodiment provides an oil pump for a pure electric powertrain assembly, such as... Figs. 1 to 3 As shown, the oil pump housing 2 is mounted on the transmission support plate 1. The oil pump housing 2 includes an oil pump main housing 21 and an oil pump cover 22. The axial rear end face of the oil pump main housing 21 is detachably mounted on the inner side wall of the transmission support plate 1, and the axial rear end face of the oil pump cover 22 is detachably mounted on the axial front end face of the oil pump main housing 21. An inner rotor shaft 3, an inner rotor 4, and an outer rotor 5 are installed inside the oil pump housing 21.

[0036] The axial front end surface of the oil pump main housing 21 is provided with a large circular groove 211, and the bottom of the large circular groove 211 is provided with a stepped blind hole 212. The large circular groove 211 and the stepped blind hole 212 are eccentrically arranged. The bottom of the large circular groove 211 is provided with a crescent-shaped first oil inlet groove 213 and a second oil outlet groove 214, and the first oil inlet groove 213 and the second oil outlet groove 214 are symmetrically arranged. The axial rear end surface of the oil pump cover body 22 is provided with a stepped through hole 221 coaxially arranged with the stepped blind hole 212.

[0037] The inner rotor 4 is placed in the outer rotor 5 and is eccentrically arranged and engaged with the outer rotor 5. The outer rotor 5 is placed in the large circular groove 211, and the outer diameter of the outer rotor 5 matches the inner diameter of the large circular groove 211. One end of the inner rotor shaft 3 is arranged in the stepped blind hole 212, and the other end of the inner rotor shaft 3 extends out of the oil pump cover body 22 through the inner rotor 4 and the stepped through hole 221 in sequence and is connected with the oil pump driven gear 6. The inner rotor 4 and the oil pump driven gear 6 are both fixedly installed on the inner rotor shaft 3 through the connecting piece 7. The oil pump driven gear 6 is engaged with the oil pump drive gear 8, and the oil pump drive gear 8 is installed on the transmission intermediate shaft 9.

[0038] In this embodiment, the transmission support plate 1 is the housing of the transmission in the pure electric power system assembly, and is fixedly connected with other housings of the transmission. The large displacement oil pump is a component installed on the transmission support plate 1. Oil is sucked into the oil pump from the transmission, and after being pressurized in the oil pump, the oil flows back to the transmission, thereby ensuring that the oil continuously lubricates the transmission. The oil pump drive gear 8 is fixedly installed with the transmission intermediate shaft 9. The oil pump drive gear 8 rotates around the transmission intermediate shaft 9 under the driving of the motor in the pure electric power system assembly. The oil pump drive gear 8 rotates with the oil pump driven gear 6. Because the oil pump drive gear 8 and the oil pump driven gear 6 have a fixed positional relationship, the gears can be correctly engaged and smoothly transmitted. The oil pump driven gear 6 drives the inner rotor shaft 3 to rotate. The stepped blind hole 212 and the stepped through hole 221 support the inner rotor shaft 3 from both ends. The inner rotor shaft 3 drives the inner rotor 4 to rotate. The connecting piece 7 is preferably a key, which ensures that the oil pump driven gear 6 and the inner rotor 4 are fixedly connected with the inner rotor shaft 3, thereby ensuring the smoothness of transmission. The inner rotor 4 has no position constraint in the axial direction, thereby avoiding excessive constraint of the inner rotor 4 and ensuring that the inner rotor 4 is easily disassembled. The inner rotor 4 rotates in the outer rotor 5. Because the inner rotor 4 and the outer rotor 5 are eccentrically arranged, the working volume of the sealed space in the oil pump housing 2 changes with the rotation of the rotor, thereby completing the oil suction and oil pressurization processes. The outer rotor 5 is constrained by the inner side wall of the large circular groove 211 in the radial direction and by the bottom surface of the large circular groove 211 and the axial rear end surface of the oil pump cover body 22 in the axial direction, thereby enabling the outer rotor 5 to stably and freely rotate in the large circular groove 211.

[0039] As a preferred form of the present embodiment, the outer rotor 5 is provided with n+1 inner teeth, and the inner rotor 4 is provided with n outer teeth. In the present embodiment, the outer rotor 5 is provided with 6 inner teeth, and the inner rotor 4 is provided with 5 outer teeth. The tooth profile of the inner teeth and the outer teeth is trochoidal. The eccentricity of the outer rotor 5 and the inner rotor 4 is e. The working volume of the oil pumping working space in the oil pump housing 2 changes with the rotation of the rotor. The working volume of the sealing space corresponding to the first oil inlet groove 213 increases, forming a local vacuum, thereby sucking the oil in the transmission into the oil pump housing 2. The working volume of the sealing space corresponding to the second oil outlet groove 214 decreases, thereby re-discharging the pressurized oil back to the transmission, providing lubrication for the transmission. The tooth profile of the inner teeth and the outer teeth is trochoidal. The meshing process of the inner rotor 4 and the outer rotor 5 is linear contact, improving the stability of the transmission. The eccentricity of the large circular groove 211 and the stepped blind hole 212 is the same as the eccentricity of the outer rotor 5 and the inner rotor 4, ensuring the stable operation of the inner and outer rotors, thereby meeting the working requirements of the oil pump.

[0040] As a preferred form of the present embodiment, the number of teeth of the oil pump driving gear 8 is greater than the number of teeth of the oil pump driven gear 6. The speed ratio of the oil pump driving gear 8 and the oil pump driven gear 6 is less than 1. This can make the oil pump obtain greater displacement at lower speed, meet the lubrication requirements of the transmission in low gear overload operating conditions, and at the same time, make the oil pump occupy smaller volume at a certain displacement, and the oil pump size is smaller, making it easier to arrange the oil pump inside the transmission.

[0041] As a preferred form of the present embodiment, the second oil inlet groove and the second oil outlet groove are moon-shaped and are provided on the axial rear end surface of the oil pump cover 22. The second oil inlet groove and the second oil outlet groove are provided corresponding to the first oil inlet groove 213 and the first oil outlet groove 214. The space surrounded by the first oil inlet groove 213, the first oil outlet groove 214, the second oil inlet groove, the second oil outlet groove, the inner teeth and the outer teeth is the oil pumping working space. The second oil inlet groove and the second oil outlet groove provide a larger working space for oil pumping.

[0042] As a preferred form of the present embodiment, the first oil inlet channel 10 and the oil pump outlet channel 11 are arranged in the transmission support plate 1, the oil inlet shell 23 is fixedly connected to the oil pump main shell 21, the second oil inlet channel 24 is arranged in the oil inlet shell 23, one end of the second oil inlet channel 24 is communicated with the first oil inlet channel 10 through the oil pump inlet 12, the other end of the second oil inlet channel 24 is communicated with the first oil inlet groove 213, and the first oil outlet groove 214 is communicated with the oil pump outlet channel 11 through the oil pump outlet 13. When the inner rotor and the outer rotor work, the oil in the transmission enters the pump working space through the first oil inlet channel 10, the oil pump inlet 12, the first oil inlet channel 10 and the first oil inlet groove 213, the oil is pressurized in the pump working space, and then flows back to the transmission through the first oil outlet groove 214, the oil pump outlet 13 and the oil pump outlet channel 11.

[0043] As a preferred form of the present embodiment, the annular groove coaxially arranged with the large circular groove 211 is arranged on the axial front end surface of the oil pump main shell 21, and the sealing ring 14 is arranged in the annular groove, so as to ensure the sealing of the connection between the oil pump main shell 21 and the oil pump cover 22, and further ensure the sealing of the pump working space, thereby improving the working stability of the oil pump.

[0044] As a preferred form of the present embodiment, the first shaft shoulder 15 and the second shaft shoulder 16 are arranged on the inner rotor shaft 3, the first shaft shoulder 15 is arranged on the axial front end surface of the inner rotor 4, the second shaft shoulder 16 is arranged on the axial rear end surface of the oil pump driven gear 6, the first steel wire retainer 17 and the second steel wire retainer 18 are further sleeved on the inner rotor shaft 3, the first steel wire retainer 17 is located on the axial rear end surface of the inner rotor 4, and the second steel wire retainer 18 is located on the axial front end surface of the oil pump driven gear 6. The inner rotor 4 is axially limited by the first shaft shoulder 15 and the first steel wire retainer 17, and the oil pump driven gear 6 is axially limited by the second shaft shoulder 16 and the second steel wire retainer 18, so as to avoid the meshing deviation of the oil pump driven gear 6 and the oil pump drive gear 8 caused by the axial movement of the inner rotor shaft 3.

[0045] As a preferred form of the present embodiment, the first support 19 is arranged in the stepped blind hole 212, and the second support 20 is arranged in the stepped through hole 221, one end of the inner rotor shaft 3 is sleeved in the first support 19, and the other end of the inner rotor shaft 3 is sleeved in the second support 20; preferably, the first support 19 and the second support 20 can be selected from a needle bearing or a sliding bearing, both ends of the support can ensure the accuracy of the central position of the inner rotor 4, and can ensure the smoothness of the rotation of the inner rotor shaft 3, so as to ensure the good dynamic balance of the oil pump, the vibration is small during movement, the noise is low, and it is more suitable for the super-speed working condition of the pure electric power system assembly.

[0046] As a preferred scheme of the embodiment, the inner wall of the stepped blind hole 212 and the inner wall of the stepped through hole 221 are both provided with an oil guide groove in the axial direction. The oil guide groove can guide the oil leaked from the end surface of the inner rotor 4 to the stepped blind hole 212 and the stepped through hole 221, so as to lubricate the first support 19 and the second support 20. The lubricated oil can flow back to the bottom of the transmission through the stepped through hole 221 of the oil pump cover body 22.

[0047] In actual operation, the embodiment has the following advantages:

[0048] The oil pump drive gear 8 is driven by the motor in the pure electric power system assembly, rotates around the center of the transmission intermediate shaft 9, and is in meshing transmission with the oil pump driven gear 6. The oil pump driven gear 6 drives the inner rotor 4 to rotate through the inner rotor shaft 3. The inner rotor 4 rotates with the outer rotor 5 to perform the oil suction and oil compression process. The speed ratio of the oil pump drive gear 8 to the oil pump driven gear 6 is less than 1. The rotation speed of the oil pump driven gear 6 is accelerated. According to the definition of displacement, the displacement of the oil pump is equal to the volume of the liquid discharged by the inner rotor 4 per revolution. The speed ratio of the oil pump drive gear 8 to the oil pump driven gear 6 is less than 1. The motor drives the oil pump drive gear 8 to rotate one circle, and the number of revolutions of the oil pump driven gear 6 and the inner rotor 4 is greater than one revolution. The oil pump obtains greater displacement from the oil pump drive gear 8, meets the demand of the transmission for large flow at low speed, and at the same time, can make the volume occupied by the oil pump smaller, the size of the oil pump smaller, and the arrangement of the oil pump in the transmission easier.

Claims

1. An oil pump for a pure electric powertrain assembly comprising an oil pump housing (2) mounted on a transmission support plate (1), characterized in that, The oil pump shell (2) comprises an oil pump main shell (21) and an oil pump cover (22), the axial rear end surface of the oil pump main shell (21) is detachably mounted on the inner side wall of the transmission support plate (1), the axial rear end surface of the oil pump cover (22) is detachably mounted on the axial front end surface of the oil pump main shell (21), and the oil pump shell (21) is internally provided with an inner rotor shaft (3), an inner rotor (4) and an outer rotor (5); The axial front end surface of the oil pump main shell (21) is provided with a large circular groove (211), the bottom of the large circular groove (211) is provided with a stepped blind hole (212), the large circular groove (211) and the stepped blind hole (212) are eccentrically arranged, the bottom of the large circular groove (211) is provided with a crescent-shaped first oil inlet groove (213) and a second oil outlet groove (214), and the first oil inlet groove (213) and the second oil outlet groove (214) are symmetrically arranged; the axial rear end surface of the oil pump cover (22) is provided with a stepped through hole (221) coaxially arranged with the stepped blind hole (212); The inner rotor (4) is placed in the outer rotor (5) and is eccentrically arranged and engaged with the outer rotor (5), the outer rotor (5) is placed in the large circular groove (211), the outer diameter of the outer rotor (5) is matched with the inner diameter of the large circular groove (211), one end of the inner rotor shaft (3) is arranged in the stepped blind hole (212), the other end of the inner rotor shaft (3) sequentially passes through the inner rotor (4) and the stepped through hole (221) and extends out of the oil pump cover (22) to be connected with an oil pump driven gear (6), the inner rotor (4) and the oil pump driven gear (6) are fixedly installed on the inner rotor shaft (3) through a connecting piece (7), the oil pump driven gear (6) is engaged with an oil pump driving gear (8), and the oil pump driving gear (8) is installed on a transmission intermediate shaft (9).

2. The oil pump for a pure electric powertrain assembly of claim 1, wherein, The outer rotor (5) is provided with n+1 inner teeth, the inner rotor (4) is provided with n outer teeth, the tooth shapes of the inner teeth and the outer teeth are both cycloid tooth shapes, and the eccentric distance between the outer rotor (5) and the inner rotor (4) is e; The eccentric distance between the large circular groove (211) and the stepped blind hole (212) is the same as the eccentric distance between the outer rotor (5) and the inner rotor (4).

3. The oil pump for a pure electric powertrain assembly of claim 1, wherein, The number of teeth of the oil pump driving gear (8) is greater than the number of teeth of the oil pump driven gear (6), and the speed ratio of the oil pump driving gear (8) to the oil pump driven gear (6) is less than 1.

4. The oil pump for a pure electric powertrain assembly of claim 2, wherein, The axial rear end surface of the oil pump cover (22) is provided with a crescent-shaped second oil inlet groove and a second oil outlet groove, and the second oil inlet groove and the second oil outlet groove are correspondingly arranged with the first oil inlet groove (213) and the first oil outlet groove (214); The space surrounded by the first oil inlet groove (213), the first oil outlet groove (214), the second oil inlet groove, the second oil outlet groove, the inner teeth and the outer teeth is a pump oil working space.

5. The oil pump for a pure electric powertrain assembly of claim 1, wherein, The transmission support plate (1) is provided with an oil pump first oil inlet channel (10) and an oil pump oil outlet channel (11), the oil pump main shell (21) is fixedly connected with an oil inlet shell (23), the oil inlet shell (23) is provided with an oil pump second oil inlet channel (24), one end of the oil pump second oil inlet channel (24) is communicated with the oil pump first oil inlet channel (10) through an oil pump oil inlet (12), the other end of the oil pump second oil inlet channel (24) is communicated with the first oil inlet groove (213), and the first oil outlet groove (214) is communicated with the oil pump oil outlet channel (11) through an oil pump oil outlet (13).

6. The oil pump for a pure electric powertrain assembly of claim 1, wherein, The oil pump main shell (21) is provided with an annular groove coaxially arranged with the large circular groove (211) on the axial front end surface, and the annular groove is provided with a sealing ring (14).

7. The oil pump for a pure electric powertrain assembly of claim 1, wherein, The inner rotor shaft (3) is provided with a first shaft shoulder (15) and a second shaft shoulder (16), the first shaft shoulder (15) is arranged on the axial front end surface of the inner rotor (4), the second shaft shoulder (16) is arranged on the axial rear end surface of the oil pump driven gear (6), and the inner rotor shaft (3) is further provided with a first steel wire retainer (17) and a second steel wire retainer (18), the first steel wire retainer (17) is arranged on the axial rear end surface of the inner rotor (4), and the second steel wire retainer (18) is arranged on the axial front end surface of the oil pump driven gear (6).

8. The oil pump for a pure electric powertrain assembly of claim 1, wherein, The first support (19) is arranged in the stepped blind hole (212), the second support (20) is arranged in the stepped through hole (221), one end of the inner rotor shaft (3) is arranged in the first support (19), and the other end of the inner rotor shaft (3) is arranged in the second support (20).

9. The oil pump for a pure electric powertrain assembly of claim 8, wherein, The first support (19) and the second support (20) are needle bearings or sliding bearings.

10. The oil pump for a pure electric powertrain assembly of claim 1, wherein, The inner wall of the stepped blind hole (212) and the inner wall of the stepped through hole (221) are both provided with oil guide grooves in the axial direction.

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