Electric pump

Abstract

An electric pump, comprising a first rotor assembly (4) and a second rotor assembly (6). The electric pump is provided with a first cavity (20) and a second cavity (30), wherein the first rotor assembly (4) is located in the first cavity (20), the second rotor assembly (6) is located in the second cavity (30), and the first rotor assembly (4) is in transmission connection with the second rotor assembly (6). The electric pump is provided with a first accommodating part (9), wherein the first accommodating part (9) comprises a bottom wall (91). The electric pump comprises a first channel (40), wherein the first channel (40) penetrates through an upper surface and a lower surface of the bottom wall (91). The first rotor assembly (4) comprises a first rotor (41) and a second rotor (42), wherein the first rotor (41) is located on the periphery of the second rotor (42). The electric pump is provided with a hydraulic cavity (43), wherein the hydraulic cavity (43) is located between the first rotor (41) and the second rotor (42) and comprises a low-pressure cavity (431). The electric pump comprises a first inflow channel (11), wherein the first inflow channel (11) is in communication with the low-pressure cavity (431), the low-pressure cavity (431) is in communication with the first channel (40), and the first channel (40) is in communication with the second cavity (30). By means of the electric pump, a working medium can enter the second cavity from the low-pressure cavity which has a lower pressure, and oil pressure in the second cavity is lower, which is beneficial to prolonging the service life of parts of the electric pump.

Description

[0001] The present application claims the priority to Chinese Patent Application No. 202310376557.4, titled "ELECTRIC PUMP", filed with the China National Intellectual Property Administration on March 31, 2023, and the priority to Chinese Patent Application No. 202310622159.6, titled "ELECTRIC PUMP", filed with the China National Intellectual Property Administration on May 30, 2023, the entire disclosures of which are incorporated herein by reference.FIELD

[0002] The present application relates to the technical field of vehicles and, in particular, to a component of a lubrication system and / or a cooling system of a vehicle.BACKGROUND

[0003] An electric pump is applied to a lubrication system and / or a cooling system of a vehicle, and the electric pump is capable of well meeting market requirements. The electric pump includes a motor chamber. When the electric pump is in operation, the oil pressure within a motor chamber is relatively high. As a result, components within the electric pump, e.g., those used for sealing purposes, are more prone to failure, which reduces the service life of the components of the electric pump.SUMMARY

[0004] An object of the present application is to provide an electric pump that enhances the service life of its components.

[0005] In order to achieve the above object, the following technical solutions are proposed in embodiments of the present application.

[0006] An electric pump includes a first rotor assembly and a second rotor assembly. The electric pump is provided with a first chamber in which the first rotor assembly is located and a second chamber in which the second rotor assembly is located. The first rotor assembly is in transmission connection to the second rotor assembly. The electric pump includes a first accommodation portion that includes a bottom wall. The electric pump further includes a first channel that passes through the bottom wall from an upper surface to a lower surface of the bottom wall. The first rotor assembly includes a first rotor and a second rotor, and the first rotor is located surrounding the second rotor. The electric pump is provided with a hydraulic chamber located between the first rotor and the second rotor. The hydraulic chamber includes a low-pressure chamber. The electric pump includes a first inlet channel that is in communication with the low-pressure chamber. The low-pressure chamber is in communication with the first channel, and the first channel is in communication with the second chamber.

[0007] In the aforementioned technical solution, the hydraulic chamber includes a low-pressure chamber that is in communication with the first channel, which is in communication with the second chamber. This allows part of the working medium within the low-pressure chamber to flow into the second chamber through the first channel, and vice versa. As the working medium enters the second chamber from the low-pressure chamber with relative low pressure, the oil pressure within the second chamber remains relatively low. Consequently, the components within the electric pump for sealing the second chamber are less prone to failure, thereby contributing to an extended service life of the components of the electric pump.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 is a schematic sectional structural view of an electric pump according to a first embodiment; FIG. 2 is a schematic view showing a partial structure of the electric pump in FIG. 1 without a pump cover being assembled; FIG. 3 is a schematic structural view of a first rotor assembly; FIG. 4 is a schematic structural view of a first housing according to a first embodiment; FIG. 5 is a schematic structural view of a first housing according to a second embodiment; FIG. 6 is a schematic sectional structural view taken along line A-A in FIG. 5; FIG. 7 is a schematic structural plan view showing an orthogonal projection of the first rotor assembly in FIG. 3 onto a bottom wall in FIG. 4; FIG. 8 is a schematic structural view of a first housing according to a third embodiment; FIG. 9 is a schematic sectional structural view taken along line A-A in FIG. 8; FIG. 10 is a schematic structural plan view showing an orthogonal projection of the first rotor assembly in FIG. 3 onto a bottom wall in FIG. 8; FIG. 11 is a schematic structural view of the pump cover in FIG. 1; FIG. 12 is another schematic structural view of the pump cover in FIG. 1; FIG. 13 is a schematic sectional structural view of an electric pump according to a second embodiment; FIG. 14 is a schematic structural view of a pump cover in FIG. 13; FIG. 15 is another schematic structural view of a pump cover in FIG. 13; FIG. 16 is a schematic structural view of a driving shaft in FIG. 1 or 13; FIG. 17 is a schematic sectional structural view of an electric pump according to a third embodiment; FIG. 18 is a schematic structural view of a first housing in FIG. 17; FIG. 19 is a schematic sectional structural view taken along line B-B in FIG. 18; FIG. 20 is a schematic structural view of a pump cover in FIG. 17; FIG. 21 is another schematic structural view of a pump cover in FIG. 17; FIG. 22 is a schematic sectional structural view taken along line B-B in FIG. 21; FIG. 23 is a schematic view of an electric pump according to a fourth embodiment of the present application; FIG. 24 is a schematic view of a first housing in FIG. 22; FIG. 25 is a schematic sectional view taken along line A-A in FIG. 24; FIG. 26 is a schematic structural plan view showing a projection of the first rotor assembly in FIG. 23 onto the chamber wall in FIG. 25 according to a first embodiment; FIG. 27 is a schematic structural plan view showing a projection of the first rotor assembly in FIG. 22 onto the chamber wall in FIG. 25 according to a second embodiment; FIG. 28 is a schematic perspective structural view of the pump shaft in FIG. 23; FIG. 29 is a schematic structural view of the pump cover in FIG. 23; FIG. 30 is another schematic structural view of the pump cover in FIG. 23; FIG. 31 is a schematic view of an electric pump according to another embodiment of the present application; FIG. 32 is a schematic view of the electric pump shown in FIG. 23 or 31 with the pump cover removed; FIG. 33 is a schematic structural view of the first housing in FIG. 31; FIG. 34 is a schematic sectional structural view taken along line A-A in FIG. 33; FIG. 35 is a schematic perspective structural view of the pump shaft in FIG. 31; FIG. 36 is a schematic structural plan view showing a projection of the first rotor assembly in FIG. 31 onto a lower end face of the pump cover; FIG. 37 is a schematic structural view of the pump cover in FIG. 31; and FIG. 38 is another schematic structural view of the pump cover in FIG. 31.

[0009] List of reference numerals: 1 pump cover, 11 first inlet channel, 12 / 15' outflow channel, 13 branch channel, 14 recessed portion, 15 second inlet channel, 2 first housing, 3 second housing, 4 first rotor assembly, 41 first rotor, 41a / 411 first mating portion, 41b second mating portion, 41c third mating portion, 42 second rotor, 43 hydraulic chamber, 431 low-pressure chamber, 431a / 4311' first low-pressure sub-chamber, 431b / 4312' second low-pressure sub-chamber, 4311 first chamber wall, 4312 second chamber wall, 432 high pressure chamber, 5 stator assembly, 51 stator core, 52 winding, 6 second rotor assembly, 7 driving shaft, 71 first end face, 72 second end face, 8 control assembly, 9 / 2a first accommodation portion, 91 bottom wall, 92 groove portion, 10 / 3a second accommodation portion, 101 chamber wall, 20 first chamber, 30 second chamber, 40 first channel, 401 first sidewall, 402 second sidewall, 405 first front end, 406 first rear end, 405a extension portion, 50 second channel, 60 third channel, 70 fourth channel, 10' inlet channel, 11' first inlet channel, 12' second inlet channel, 13' second branch channel, 16 second channel, 23 first branch channel, 231 sub-branch channel, 23a first sidewall, 23b second sidewall, 71' first end, 72' second end, 73 first channel, 74 first opening, 75 second opening, 201, chamber wall, 2011 first groove, 2011a first groove wall, 2011b second groove wall, 2011c front end, 2011d back end, 301 bottom wall.DETAILED DESCRIPTION OF THE EMBODIMENTS

[0010] The present application will be further explained with reference to the accompanying drawings by means of embodiments.

[0011] In order to make those skilled in the art better understand the technical solutions of the present application, the present application will be further explained in detail with reference to the accompanying drawings by means of embodiments. Obviously, the accompanying drawings used in the following description involve only some of the embodiments of the present application. Based on these accompanying drawings, those skilled in the art can obtain other drawings without creative work. The orientation terms such as "upper" and "lower" mentioned herein are defined with reference to the relative positions of the components shown in the accompanying drawings, only for the purpose of clearly and conveniently expressing the technical solutions. It should be understood the orientation terms used herein shall not limit the protection scope claimed in the present application.

[0012] Referring to FIGS. 1 to 38, an electric pump includes a pump housing, which includes a pump cover 1, a first housing 2, and a second housing 3. The pump cover 1 is fixedly connected to the first housing 2. For example, the pump cover 1 is fixedly connected to the first housing 2 by screws or bolts. Alternatively, the pump cover 1 may be connected to the first housing 2 in any other connection manner, e.g., plug-in or snap-fit connection manner. The first housing 2 is fixedly connected to the second housing 3. The first housing 2 is fixedly connected to the second housing 3, for instance, by screws or bolts, which facilitates convenient assembly and disassembly of the electric pump.

[0013] Referring to FIGS. 1 to 38, the electric pump includes a first rotor assembly 4, a stator assembly 5, a second rotor assembly 6, a driving shaft (or pump shaft) 7, and a control assembly 8. The stator assembly 5 is located radially outside of the second rotor assembly 6 and surrounds the second rotor assembly 6. The driving shaft (or pump shaft) 7 is in transmission connection to the second rotor assembly 6. The electric pump has a first accommodation portion 9 or 2a and a second accommodation portion 10 or 3a. In this embodiment, the pump housing is formed with the first and second accommodation portions 9 or 2a and 10 or 3a. Specifically, the first accommodation portion 9 or 2a is defined by the pump cover 1 and the first housing 2, and the second accommodation portion 10 or 3a is defined by the first housing 2 and the second housing 3. The first accommodation portion 9 or 2a has a first chamber 20, and the second accommodation portion 10 has a second chamber 30. The first chamber 20 is in communication with the second chamber 30. For example, after the pump cover 1 is fixedly connected to the first housing 2, the first accommodation portion 9 or 2a is formed; and after the first housing 2 is fixedly connected to the second housing 3, the second accommodation portion 10 or 3a is formed. The electric pump includes a first rotor assembly 4, a stator assembly 5, a second rotor assembly 6, a driving shaft (or pump shaft) 7, and a control assembly 8. The stator assembly 5 is located radially outside of the second rotor assembly 6 and surrounds the second rotor assembly 6, and the first rotor assembly 4 is in transmission connection to the second rotor assembly 6. The first rotor assembly 4 (or at least part of it) is located in the first chamber 20 (or within the first accommodation portion 9 or 2a). At least part of the control assembly 8, the second rotor assembly 6 (or at least part of it), at least part of the driving shaft (or pump shaft) 7, and the stator assembly 5 (or at least part of it) are located in the second chamber 30 (or within the second accommodation portion 10, 3a). The stator assembly 5 and the control assembly 8 are located in the same chamber, which can have a compact structure with reduced axial size and thus can reduce the production costs, compared with an electric pump having the stator assembly 5 and the control assembly 8 in different chambers in an axial direction of the electric pump.

[0014] Referring to FIGS. 1 to 38, the first rotor assembly 4 includes a first rotor 41 and a second rotor 42. The first rotor 41 includes several internal teeth, and the second rotor 42 includes several external teeth. The first rotor 41 is positioned outside of the second rotor 42, and is meshed with the second rotor 42. In other embodiments, the first rotor 41 and the second rotor 42 may be externally meshed with each other, in which case the first rotor 41 and the second rotor 42 may be arranged side by side. In this embodiment, a central axis of the first rotor 41 is offset from a central axis of the second rotor 42, meaning there is a certain eccentricity between the axes of the first and second rotors 41 and 42. When the second rotor 42 rotates, at least part of its external teeth engage with at least part of the internal teeth of the first rotor 41, enabling the second rotor 42 to drive the first rotor 41 to rotate. The electric pump includes a hydraulic chamber 43, which is located between the first rotor 41 and the second rotor 42. The stator assembly 5 includes a stator core (as indicated by 51 in FIG. 1) and windings (as indicated by 52 in FIG. 1). When the electric pump is in operation, the control assembly 8 controls the current in the windings of the stator assembly 5 to vary regularly, thereby controlling the stator assembly 5 to generate a varying excitation magnetic field. The second rotor assembly 6 rotates under an influence of this excitation magnetic field and can directly or indirectly drive the first rotor assembly 4 to rotate. In this embodiment, the driving shaft (or pump shaft) 7 is in transmission connection to both the first rotor assembly 4 and the second rotor assembly 6. Specifically, the driving shaft (or pump shaft) 7 is connected to the second rotor 42 and the second rotor assembly 6 at different axial positions. The second rotor assembly 6 drives the driving shaft (or pump shaft) 7, which in turn drives the second rotor 42 to rotate, thereby achieving the rotation of the first rotor assembly 4.

[0015] Referring to FIGS. 1 to 38, the electric pump includes a first inlet channel 11 (or a second inlet channel 12') and an outlet channel 12 or 15'. The first inlet channel 11 (or the second inlet channel 12') is used for inflow of working medium, and the outlet channel 12 or 15' is used for outflow of the working medium. Specifically, the working medium can enter the hydraulic chamber 43 through the first inlet channel 11 (or the second inlet channel 12') and exit the hydraulic chamber 43 through the outlet channel 12. During one complete rotation of the first rotor assembly 4, a volume of the hydraulic chamber 43 between at least one internal tooth of the first rotor 41 and the corresponding external tooth of the second rotor 42 may be varied. Specifically, as the first rotor assembly 4 rotates from its starting position to a certain angle, the volume of the hydraulic chamber 43 formed between at least one internal tooth of the first rotor 41 and the corresponding external tooth of the second rotor 42 gradually increases, thus creating a partial vacuum. At this time, the working medium is drawn into the hydraulic chamber 43 through the first inlet channel 11 (or the second inlet channel 12'). As the first rotor 41 and the second rotor 42 continue to rotate, the volume of the hydraulic chamber 43 formed between at least one internal tooth of the first rotor 41 and the corresponding external tooth of the second rotor 42 gradually decreases, thus compressing the working medium. Thus, the working medium that has entered the hydraulic chamber 43 is expelled into the outlet channels 12 or 15', thereby generating the motive force for flow.

[0016] Referring to FIGS. 1 to 38, the hydraulic chamber 43 includes a low-pressure chamber 431 and a high-pressure chamber 432. To more clearly distinguish between the low-pressure chamber 431 and the high-pressure chamber 432, reference is made to FIGS. 3, 7, 10, 26, 27, and 36, where two different hatching patterns are used to differentiate them. In an embodiment, referring to FIG. 1, the first rotor assembly 4 rotates counterclockwise. The term "counterclockwise" used herein is defined based on the top view of the electric pump as shown in FIG. 1, which is not sectioned. The low-pressure chamber 431 includes several low-pressure sub-chambers, and the high-pressure chamber 432 includes several high-pressure sub-chambers. Along a rotation direction of the first rotor assembly 4, the volume of the low-pressure sub-chambers gradually increases to create a partial vacuum, which draws the working medium into these low-pressure sub-chambers. Along the rotation direction of the first rotor assembly 4, the volume of the high-pressure sub-chambers in the high-pressure chamber 432 gradually decreases to compress the working medium, which is then expelled from these high-pressure sub-chambers, generating the motive force for flow.

[0017] Referring to FIGS. 1 to 17, the first accommodation portion 9 includes a bottom wall 91 that can support the first rotor assembly 4. The first chamber 20 is located at one side of the bottom wall 91, and the second chamber 30 is located at the other side of the bottom wall 91. The electric pump includes a first channel 40 that passes through the bottom wall 91 from an upper surface to a lower surface of the bottom wall 91. The first channel 40 enables communication between the first chamber 20 and the second chamber 30. That is, the first channel 40 is in communication with both the first chamber 20 and the second chamber 30. When the electric pump is in operation, part of the working medium in the low-pressure chamber 431 flows into the second chamber 30 through the first channel 40, and part of the working medium in the second chamber 30 flows into the low-pressure chamber 431 through the first channel 40. The working medium enters the second chamber 30 from the low-pressure chamber 431, where the oil pressure is relatively low. The oil pressure in the second chamber 30 is also relatively low so that the components for sealing the second chamber 30 within the electric pump are not easily failed, thereby improving the service life of the components of the electric pump.

[0018] Referring to FIGS. 3, 7, 10, 26, 27, and 36, the low-pressure chamber 431 includes a first low-pressure sub-chamber 431a or 4311' and a second low-pressure sub-chamber 431b or 4312'. The first rotor 41 has a first mating portion 41a or 411 that meshes with the second rotor 42. In a circumferential direction of the first rotor assembly 4, the first low-pressure sub-chamber 431a or 4311' and the second low-pressure sub-chamber 431b or 4312' are located on opposite sides of the first mating portion 41a or 411.

[0019] Referring to FIGS. 1 to 22, the first channel 40 includes a first subsection and a second subsection. The first subsection of the first channel 40 faces the first low-pressure sub-chamber 431a and is in communication with the first low-pressure sub-chamber 431a, and the second subsection of the first channel 40 faces the second low-pressure sub-chamber 431b and is in communication with the second low-pressure sub-chamber 431b. The pressure in the first low-pressure sub-chamber 431a is greater than that in the second low-pressure sub-chamber 431b. Based on the principle that the working medium flows from areas with high pressure to areas with low pressure, part of the working medium in the first low-pressure sub-chamber 431a flows into the second chamber 30 through the first channel 40, and at least part of the working medium in the second chamber 30 flows into the second low-pressure sub-chamber 431b through the first channel 40. The working medium enters the second chamber 30 from the low-pressure chamber 431 with relatively low pressure, and the oil pressure in the second chamber 30 is relatively low. The components for sealing the second chamber 30 within the electric pump are not prone to failure, thereby improving the service life of the components of the electric pump. Additionally, the working medium entering the second chamber 30 can come into contact with the stator assembly 5, thus facilitating heat dissipation of the stator assembly 5.

[0020] Referring to FIGS. 1 to 22, the first channel 40 further includes a first front end 405 and a first rear end 406. In the circumferential direction of the first rotor assembly 4, the first front end 405 is farther from the high-pressure chamber 432 than the first rear end 406. Referring to FIG. 7 or 10, in conjunction with FIG. 1, 13, or 17, the first rotor 41 has a second mating portion 41b that meshes with the second rotor 42. In the circumferential direction of the first rotor assembly 4, the second mating portion 41b is closer to the high-pressure chamber 432 than the first mating portion 41a. The first front end 405 is located between the first mating portion 41a and the second mating portion 41b, which can relatively increase the volume of the second low-pressure sub-chamber 431b. This facilitates increase of flow rate of the working medium returning from the second chamber 30 to the low-pressure chamber 431 (or the second low-pressure sub-chamber 431b) per unit time, thereby improving pump efficiency.

[0021] In another embodiment, referring to FIGS. 5 to 7, the first channel 40 includes a first front end 405 and a first rear end 406. In the circumferential direction of the first rotor assembly 4, the first front end 405 is farther from the high-pressure chamber 432 than the first rear end 406. The first front end 405 includes an extension portion 405a. The first rotor 41 has a third mating portion 41c that meshes with the second rotor 42. In the circumferential direction of the first rotor assembly 4, the low-pressure chamber 431 and the high-pressure chamber 432 are located on opposite sides of the third mating portion 41c. The extension portion 405a is closer to the second mating portion 41b than the third mating portion 41c. With this arrangement, in addition to ensuring sealing between the low-pressure chamber 431 and the high-pressure chamber 432, the flow area of the working medium can be increased, thereby increasing its flow velocity. In this embodiment, the surface of the extension portion 405a is inclined, which facilitates guiding the working medium in the second chamber 30 into the low-pressure chamber 431 (or the second low-pressure sub-chamber 431b), and thus facilitates smooth flow of part of the working medium from the first channel 40 into the low-pressure chamber 431 (or the second low-pressure sub-chamber 431b). In other embodiments, the cross-section of the extension portion 405a in the radial direction of the first rotor assembly 4 may be circular, elliptical or the like in shape.

[0022] In an embodiment, referring to FIGS. 8 to 10, the electric pump further includes a second channel 50 that passes through the bottom wall 91 from the upper surface to the lower surface of the bottom wall 91 of the first accommodation portion 9. The second channel 50 enables communication between the first chamber 20 and the second chamber 30. The second channel 50 is in communication with both the first chamber 20 and the second chamber 30. The first rotor 41 has a third mating portion 41c that meshes with the second rotor 42. In the circumferential direction of the first rotor assembly 4, the low-pressure chamber 431 and the high-pressure chamber 432 are located on opposite sides of the third mating portion 41c. The second channel 50 is closer to the third mating portion 41c than the first front end 405. With this arrangement, in addition to ensuring sealing between the low-pressure chamber 431 and the high-pressure chamber 432, the flow area of the working medium can be increased, thereby increasing its flow velocity.

[0023] Referring to FIGS. 4 to 10, the first channel 40 includes a first sidewall 401 and a second sidewall 402. Correspondingly, the low-pressure chamber 431 includes a first chamber wall 4311 and a second chamber wall 4312. In the radial direction of the first rotor 41, the first chamber wall 4311 is the farthest from a central axis of the first rotor 41 (or a center O 1 of an orthogonal projection of the first rotor 41 onto the bottom wall 91). In the radial direction of the second rotor 42, the second chamber wall 4312 is the closest to the central axis of the second rotor 42 (or the center O 2 of an orthogonal projection of the second rotor 42 onto the bottom wall 91). In the radial direction of the first rotor assembly 4, the first sidewall 401 is closer to the central axis of the second rotor 42 than the second sidewall 402, and is closer to the central axis of the first rotor 41 than the first chamber wall 4311, and the second sidewall 402 is farther from the central axis of the second rotor 42 than the second chamber wall 4312. This configuration allows part of the working medium in the low-pressure chamber 431 to flow into the second chamber 30 through the first channel 40, and part of the working medium in the second chamber 30 to flow back into the low-pressure chamber 431. When the first rotor assembly 4 and the first channel 40 are orthogonally projected onto the bottom wall 91 of the first accommodation portion 9, at least part of the projection of the low-pressure chamber 431 (or the subsequently mentioned first accommodation section) lies between the projections of the first sidewall 401 and the second sidewall 402. In view ofthe projections, the first sidewall 401 is tangent to the root of an external tooth of the second rotor 42, or is closer to an edge of a hole of the second rotor 42 than the root of the external tooth of the second rotor 42, and the second sidewall 402 is tangent to the root of an internal tooth of the first rotor 41, or is closer to an outer edge of the first rotor 41 than the root of the internal tooth of the first rotor 41. Here, "tangent" refers to a theoretical tangency, considering a tolerance allowed during actual manufacture or assembly of parts. The deviations within the machining or assembly tolerance shall be considered to be within the scope of the protection of the present application. In this way, at least part of the projection of the first channel 40 overlaps with or falls within the projection of the low-pressure chamber 431 (or the subsequently mentioned first accommodation section), allowing part of the working medium in the low-pressure chamber 431 to enter the second chamber 30 through the first channel 40. The first channel 40 further includes a first front end 405 and a first rear end 406. In the circumferential direction of the first rotor assembly 4, the first front end 405 is farther from the high-pressure chamber 432 than the first rear end 406. The distance between the first sidewall 401 and the second sidewall 402 in the direction perpendicular to the central axis of the second rotor 42 gradually increases from the first rear end 406 to the first front end 405. Along the rotation direction of the first rotor assembly 4, the volume of the first channel 40 is varied with variation in volume of the working medium within the low-pressure chamber 431. This facilitates increase a flow rate of the working medium entering the second chamber 30 per unit time and increase of a flow rate of the working medium returning from the second chamber 30 to the low-pressure chamber 431 (or the second low-pressure sub-chamber 431b) per unit time, thereby improving pump efficiency.

[0024] Both the first sidewall 401 and the second sidewall 402 are arcuate in shape, which facilitates the flow of the working medium. In this embodiment, the first sidewall 401 is coaxially arranged with the second rotor 42, and the second sidewall 402 is coaxially arranged with the first rotor 41. Here, "coaxially" refers to a theoretical coaxiality, considering a tolerance allowed during actual manufacture or assembly of parts. The deviations within the machining or assembly tolerance shall be considered to be within the scope of the protection ofthe present application. In the radial direction of the second rotor 42, a distance between the first sidewall 401 and the central axis of the second rotor 42 is denoted as D1, and a distance between the central axis of the second rotor 42 and the inner sidewall ofthe first accommodation portion 9 is denoted as D2. The ratio of D1 to D2 ranges from 1:1.5 to 4:1, or preferably from 1:2 to 3:1. The distance between the second sidewall 402 and the central axis of the first rotor 41 is denoted as D3, and the distance between the central axis of the first rotor 41 and the inner sidewall of the first accommodation portion 9 is denoted as D4. The ratio of D3 to D4 ranges from 1:1 to 3:1, or preferably from 1:1.2 to 2:1. As such, it is possible to have a large flow area of the working medium. In the radial direction of the second rotor 42, the distance between the first sidewall 401 and the central axis of the second rotor 42 ranges from 3mm to 6mm, or preferably from 3.5mm to 6mm or from 3mm to 5.5mm, or more preferably from 3.5mm to 5.5mm. With this arrangement, in addition to ensuring sealing between the low-pressure chamber 431 and the high-pressure chamber 432, the first rotor assembly 4 can be sufficiently supported by the bottom wall 91 of the first accommodation portion 9 when the electric pump initially operates, and the friction between the first rotor assembly 4 and the bottom wall 91 of the first accommodation portion 9 can be reduced during stable operation of the electric pump. In the radial direction of the first rotor 41, the distance between the second sidewall 402 and the central axis of the first rotor 41 ranges from 15mm to 22mm, or preferably from 16mm to 22mm or from 15mm to 21mm, or more preferably from 16mm to 21mm. In other embodiments, in the radial direction of the first rotor 41, the distance between the second sidewall 402 and the inner sidewall of the first accommodation portion 9 ranges from 0mm to 3mm, or preferably from 1mm to 3mm, or more preferably from 1mm to 2.5mm. As such, it is possible to have a large flow area of the working medium.

[0025] Referring to FIGS. 3 to 8, the bottom wall 91 has a groove portion 92 that is recessed from the upper surface of the bottom wall 91 towards the lower surface of the bottom wall 91 without extending through the lower surface of the bottom wall 91. When the first rotor assembly 4 is orthogonally projected onto the bottom wall 91, the first rotor assembly 4 includes an accommodation section (not shown) located between the first rotor 41 and the second rotor 42. This accommodation section has a hydraulic chamber 431 and includes a first accommodation section (not shown) and a second accommodation section (not shown). The first accommodation section includes a low-pressure chamber 431, a first chamber wall 4311 and a second chamber wall 4312. The second accommodation section includes a high-pressure chamber 432. At least part of the projection of the high-pressure chamber 432 (or the second accommodation section) lies within the groove portion 92. By providing the groove portion 92, some of the working medium can be retained within the groove portion 92 during the operation of the electric pump. This facilitates the formation of an oil film between the first rotor assembly 4 and the bottom wall 91, which in turn reduces the friction between the first rotor assembly 4 and the bottom wall 91 during rotation, thereby minimizing noise caused by friction.

[0026] Referring to FIGS. 1, 13, and 16, the electric pump includes a third channel 60 that allows the working medium to enter the second chamber 30, enabling the working medium to come into contact with the control assembly 8 within the second chamber 30, thus facilitating heat dissipation of the control assembly 8. Along the axial direction of the driving shaft 7, the third channel 60 passes through the driving shaft 7 from a first end face 71 to a second end face 72. In this embodiment, the cross-section of the third channel 60 is in the form of a circular hole. In other embodiments, the cross-section of the third channel 60 may be in the form of a square hole or in any other form. The central axis of the third channel 60 coincides with the central axis of the driving shaft 7. Here, "coincide" refers to a theoretical coincidence, considering a coincidence tolerance allowed during actual manufacture. The deviations within the machining tolerance shall be considered to be within the scope of the protection of the present application.

[0027] Referring to FIGS. 1 to 38, the first inlet channel 11 (or the second inlet channel 12'), and the outlet channel 12 or 15', are all formed in the pump cover 1. The first inlet channel 11 (or the second inlet channel 12') passes through the pump cover 1 from the upper end face to the lower end face of the pump cover 1, and the outlet channel 12 or 15' is recessed from the lower end face of the pump cover 1 without extending through the upper end face of the pump cover 1. In an embodiment, referring to FIGS. 1, 11 to 12, and 16, the pump cover 1 further includes a branch channel 13 and a recessed portion 14, which are both recessed from the lower end face of the pump cover 1. The branch channel 13 enables communication between the first inlet channel 11 and the recessed portion 14, allowing the working medium to flow into the recessed portion 14 through the branch channel 13. At least part of the driving shaft 7 is located within the recessed portion 14, with a gap existing between the first end face 71 of the driving shaft 7 and the bottom wall of the recessed portion 14 in the axial direction of the pump cover 1. Some of the working medium entering the recessed portion 14 can flow into the third channel 60. The third channel 60 is not in communication with the outlet channel 12. The low-pressure chamber 431 is in communication with the first inlet channel 11 but not in communication with the outlet channel 12, and the high-pressure chamber 432 is in communication with the outlet channel 12 but not in communication with the first inlet channel 11. When the first rotor assembly 4, the first inlet channel 11, and the outlet channel 12 are orthogonally projected on a plane parallel to the upper end face of the first rotor 41, the projection of part of the low-pressure chamber 431 (or part of the first accommodation section) lies within the projection of the first inlet channel 11, and the projection of the low-pressure chamber 431 (or the first accommodation section) does not lie within the projection of the outlet channel 12; the projection of the high-pressure chamber 432 (or the second accommodation section) lies within the projection of the outlet channel 12. This configuration helps prevent the working medium in the high-pressure chamber 432 from flowing back into the low-pressure chamber 431, thereby reducing flow loss and improving pump efficiency.

[0028] References are made to FIGS. 1 to 12 and 16. FIG. 1 illustrates flow directions of the working medium. There are three flow directions for the working medium. To better explain these, in FIG. 1, S1 represents a first flow direction, and S2 represents a second flow direction, and S3 represents a third flow direction. In the first flow direction, the working medium flows from the first inlet channel 11 into the hydraulic chamber 43 of the first rotor assembly 4 and then exits the hydraulic chamber 43 through the outlet channel 12. In the second flow direction, part of the working medium within the hydraulic chamber 43 (or the low-pressure chamber 431) flows into the second chamber 30 through the first channel 40, and part of the working medium within the second chamber 30 then returns to the hydraulic chamber 43 (or the low-pressure chamber 431) through the first channel 40 and exits the hydraulic chamber 43 through the outlet channel 12. In the third flow direction, part of the working medium within the branch channel 13 flows into the second chamber 30 through the third channel 60. Both the control assembly 8 and the stator assembly 5 are located in the second chamber 30, so that the working medium flowing into the second chamber 30 comes into contact with the control assembly 8 and the stator assembly 5 and thus exchanges heat with the control assembly 8 and the stator assembly 5. During the operation of the electric pump, the pressure of the working medium at the inlet of the third channel 60 is greater than that at the outlet of the first channel 40. Based on the principle that the working medium flows from areas with high pressure to areas with low pressure, the working medium exits the second chamber 30 through the first channel 40.

[0029] References are made to FIGS. 13 to 16. FIG. 13 illustrates a schematic view of the electric pump according to a second embodiment of the present application. The second embodiment is different from the first embodiment in that the electric pump includes a pump cover 1, a second inlet channel 15 extending through the pump cover 1 from the upper end face to the lower end face of the pump cover 1, and a third channel 60 passing through the driving shaft 7 from the first end face 71 to the second end face 72 of the driving shaft 7. The second inlet channel 15 is in communication with the third channel 60, and the third channel 60 is in communication with the second chamber 30. FIG. 13 depicts flow directions of the working medium. There are three flow directions for the working medium. To better explain these, in FIG. 13, S1 represents a first flow direction, and S2 represents a second flow direction, and S3 represents a third flow direction. In the first flow direction, the working medium flows from the first inlet channel 11 into the hydraulic chamber 43 of the first rotor assembly 4 and then exits the hydraulic chamber 43 through the outlet channel 12. In the second flow direction, part of the working medium within the hydraulic chamber 43 (or the low-pressure chamber 431) flows into the second chamber 30 through the first channel 40, and part of the working medium within the second chamber 30 then returns to the hydraulic chamber 43 (or the low-pressure chamber 431) through the first channel 40 and exits the hydraulic chamber 43 through the outlet channel 12. In the third flow direction, part of the working medium within the second inlet channel 15 flows into the second chamber 30 through the third channel 60. Both the control assembly 8 and the stator assembly 5 are located within the second chamber 30, so that the working medium flowing into the second chamber 30 comes into contact with the control assembly 8 and the stator assembly 5 and thus exchanges heat with the control assembly 8 and the stator assembly 5. During the operation of the electric pump, the pressure of the working medium at the inlet of the third channel 60 is greater than that at the outlet of the first channel 40, enabling the working medium to exit the second chamber 30 through the first channel 40. In other embodiments, at least part of the pump shaft 7 is positioned within the second inlet channel 15, allowing the working medium to directly flow into the second chamber 30 through the third channel 60.

[0030] References are made to FIGS. 17 to 22. FIG. 17 illustrates a schematic view of the electric pump according to a third embodiment of the present application. The third embodiment is different from the first embodiment in that the electric pump further includes a second inlet channel 15 and a fourth channel 70. The second inlet channel 15 is formed in the pump cover 1 and passes through the pump cover 1 from the upper end face to the lower end face of the pump cover 1. The second accommodation section 10 or the second chamber 30 includes a chamber wall 101. The fourth channel 70 passes through the chamber wall 101 from the upper end face to the lower end face of the chamber wall 101, allowing part of the working medium within the second inlet channel 15 to enter the second chamber 30 through the fourth channel 70. Along the flow direction of the working medium within the second inlet channel 15, a length of the second inlet channel 15 is denoted as d1, and a distance between the upper end face and lower end face of the pump cover 1 in the axial direction of the pump cover 1 is denoted as d2. Here, d1 is greater than d2. The second inlet channel 15 is inclined at a certain angle, enabling the working medium to flow through the second inlet channel 15 at a relatively high flow velocity.

[0031] References are made to FIGS. 17 to 22. FIG. 22 depicts flow directions of the working medium. There are three flow directions for the working medium. To better explain these, in FIG. 17, S1 represents a first flow direction, and S2 represents a second flow direction, and S3 represents a third flow direction. In the first flow direction, the working medium flows from the first inlet channel 11 into the hydraulic chamber 43 of the first rotor assembly 4 and then exits the hydraulic chamber 43 through the outlet channel 12. In the second flow direction, part of the working medium within the hydraulic chamber 43 (or the low-pressure chamber 431) flows into the second chamber 30 through the first channel 40, and part of the working medium within the second chamber 30 then returns to the hydraulic chamber 43 (or the low-pressure chamber 431) through the first channel 40 and exits the hydraulic chamber 43 through the outlet channel 12. In the third flow direction, part of the working medium within the second inlet channel 15 flows into the second chamber 30 through the fourth channel 70. Both the control assembly 8 and the stator assembly 5 are located within the second chamber 30, so that the working medium flowing into the second chamber 30 comes into contact with the control assembly 8 and the stator assembly 5 and then exchanges heat with the control assembly 8 and the stator assembly 5. During the operation of the electric pump, the pressure of the working medium at the inlet of the fourth channel 70 is greater than that at the outlet of the first channel 40. Based on the principle that the working medium flows from areas with high pressure to areas with low pressure, the working medium can exit the second chamber 30 through the first channel 40.

[0032] Referring to FIGS. 23 to 38, the wall forming the second chamber 30 includes a base wall 301. The electric pump is provided with an inlet channel 10' that has an opening in the base wall 301 and is in communication with the second chamber 30. The pump shaft 7 includes a first channel 73 that is in communication with the second chamber 30. The hydraulic chamber 43 includes a low-pressure chamber 431, and the first channel 73 is in communication with the low-pressure chamber 431. During the operation of the electric pump, the working medium within the inlet channel 10' flows into the second chamber 30. Part of the working medium within the second chamber 30 can then flow into the low-pressure chamber 431 through the first channel 73. The pressure of the working medium within the second chamber 30 may be the same as the external pressure of the electric pump, and is relatively low. This configuration helps prevent the components for sealing the second chamber 30 within the electric pump from failing, thereby improving the service life of the components of the electric pump.

[0033] Referring to FIGS. 23 to 38, the inlet channel 10' includes a first inlet channel 11' and a second channel 16. The second channel 16 is in communication with the first inlet channel 11' and also in communication with the second chamber 30. The second channel 16 has an opening in the base wall 301. The first inlet channel 11' passes through the pump cover 1 from the upper surface to the lower surface of the pump cover 1. The electric pump is provided with at least two first inlet channels 11', which are distributed along the circumferential direction of the pump cover 1. The number of the first inlet channels 11' is not less than the number of the second channels 16. the larger the number of first inlet channels 11' is, the more the working medium enters the second chamber 30, resulting in a fast heat dissipation rate for the stator assembly 5 (or both the stator assembly 5 and the control assembly 8) located within the second chamber 30. In the axial direction of the pump cover 1, there is a first distance d1 between the upper surface and the lower surface of the pump cover 1. The length d2 of the first inlet channel 11' is greater than this first distance d1. The first inlet channel 11' is inclined at a certain angle, enabling the working medium to flow through the first inlet channel 11' at a relatively high flow velocity.

[0034] References are made to FIGS. 23 to 30. FIG. 23 illustrates a schematic structural view of the electric pump according to an embodiment of the present application. The pump shaft 7 includes a first end 71' and a second end 72'. Along the axial direction of the pump shaft 7, the first end 71' is closer to the first rotor assembly 4 than the second end 72'. The first channel 73 has a second opening 75 and at least one first opening 74. The first opening 74 is located on the outer sidewall of the first end 71', and the second opening 75 is located on the end face of the second end 72' and is in communication with the second chamber 30. The electric pump includes a first branch channel 23 that enables communication between the first opening 74 and the low-pressure chamber 431. The pressure at the inlet of the second channel 16 is greater than the pressure in the low-pressure chamber 431. Part of the working medium within the second chamber 30 can flow into the low-pressure chamber 431 through the first channel 73. The pressure of the working medium within the second chamber 30 may be the same as the pressure outside the electric pump, and is relatively low. With this configuration, the components for sealing the second chamber 30 within the electric pump are not prone to failure, thereby improving the service life of the components of the electric pump. Additionally, since the stator assembly 5 (or both the stator assembly 5 and the control assembly 8) is located within the second chamber 30, the flowing working medium can carry away at least part of the heat from the stator assembly 5 (or both the stator assembly 5 and the control assembly 8), thereby improving the heat dissipation efficiency of the stator assembly 5 (or both the stator assembly 5 and the control assembly 8).

[0035] Referring to FIGS. 23 to 38, the electric pump includes a chamber wall 201. In the axial direction of the electric pump, the first chamber 20 is located on one side ofthe chamber wall 201, and the second chamber 30 is located on the other side of the chamber wall 201. Referring to FIGS. 24 to 29, the chamber wall 201 has a first groove 2011. In the axial direction of the electric pump, the low-pressure chamber 431 faces the first groove 2011. The first groove 2011 is recessed from the upper surface of the chamber wall 201 towards the lower surface of the chamber wall 201 but does not extend through the lower surface of the chamber wall 201. The first groove 2011 includes a first groove wall 2011a and a second groove wall 2011b. In the radial direction of the first rotor assembly 4, the first groove wall 2011a is closer to the central axis of the first rotor 41 than the second groove wall 20 11b. The first branch channel 23 extends from the first groove wall 2011a towards the pump shaft. By providing the first groove 2011, some of the working medium can be retained within the first groove 2011 during the operation of the electric pump. This facilitates the formation of a lubricating film between the first rotor assembly 4 and the upper surface of the chamber wall 201, which in turn reduces the friction between the first rotor assembly 4 and the upper surface of the chamber wall 201 during rotation, thereby reducing noise caused by friction. The first groove 2011 has a front end 2011c and a rear end 2011d. The front end 2011c is located at one end of the first groove wall 2011a and one end of the second groove wall 2011b, and the rear end 2011d is located at the other end of the first groove wall 2011a and the other end of the second groove wall 2011b. In the circumferential direction of the first rotor assembly 4, the first branch channel 23 is located between the front end 2011c and the rear end 2011d. In this way, in addition to achieving sealing between the low-pressure chamber 431 and the high-pressure chamber 432, the chamber wall 201 can provide sufficient support for the first rotor assembly 4 at the initial operation of the electric pump, and the friction between the first rotor assembly 4 and the upper surface of the chamber wall 201 can be reduced when the electric pump runs stably.

[0036] Referring to FIGS. 26 and 27, the first branch channel 23 includes at least two sub-branch channels 231, which are arranged along the circumferential direction of the first rotor assembly 4 to accelerate the flow rate of the working medium. Alternatively, the first branch channel 23 has a first sidewall 23a and a second sidewall 23b, with a distance between them gradually increasing from the pump shaft 7 to the first groove wall 2011a. Along the flow direction of the working medium within the first branch channel 23, the distance between the first sidewall 23a and the second sidewall 23b gradually increases, which can gradually decrease the flow velocity of the working medium within the first branch channel and increase the flow velocity of the working medium within the second chamber, which is beneficial for improving the heat dissipation efficiency of the stator assembly (or the stator assembly and control assembly).

[0037] The pressure in the first low-pressure sub-chamber 4311' is greater than that in the second low-pressure sub-chamber 4312'. In the radial direction of the first rotor assembly 4, the first branch channel 23 is in communication with the second low-pressure sub-chamber 4312'. This can relatively increase the pressure difference between the working medium in the second chamber 30 and that in the low-pressure chamber 431, enabling the working medium to effectively flow into the second chamber 30 and come into contact with the stator assembly 5 (or the stator assembly 5 and control assembly 8) located within the second chamber 30, thereby facilitating heat dissipation from the stator assembly 5 (or the stator assembly 5 and control assembly 8).

[0038] References are made to FIGS. 31 to 38. FIG. 31 illustrates a schematic structural view of the electric pump according to another embodiment of the present application. The pump shaft 7 is fixedly connected to the first rotor assembly 4 and also to the second rotor assembly 6. Any means of connection that enables power transmission between the first rotor assembly 4 and the second rotor assembly 6 is encompassed within the scope of fixed connection as described herein. The pump shaft 7 includes a first end 71' and a second end 72'. Along the axial direction of the pump shaft 7, the first end 71' is closer to the first rotor assembly 4 than the second end 72'. The electric pump is provided with a first channel 73 that passes through from the first end face of the first end 71' to the second end face of the second end 72'. The pump cover 1 includes a second branch channel 13', which enables communication between the first channel 73 and the low-pressure chamber 431. The pressure at the inlet of the second channel 16 is greater than the pressure in the low-pressure chamber 431. This creates a pressure difference of working medium between the inlet of the second channel 16 and the low-pressure chamber 431. Bases on the principle that the working medium flows from areas with high pressure to areas with low pressure, the working medium within the second chamber 30 can flow towards the low-pressure chamber 431. Since the stator assembly 5 (or both the stator assembly 5 and the control assembly 8) are located within the second chamber 30, the flowing working medium can carry away at least part of the heat from the stator assembly 5 (or both the stator assembly 5 and the control assembly 8), thereby improving the heat dissipation efficiency of the stator assembly 5 (or both the stator assembly 5 and the control assembly 8). In this embodiment, the cross-section of the first channel 73 is in the form of a circular hole. In other embodiments, the cross-section of the first channel 73 may be in the form of a square hole or in any other form. The central axis of the first channel 73 coincides with the central axis of the pump shaft 7. "Coincide" refers to theoretical coincidence, considering a coincidence tolerance allowed during actual manufacture. The deviations within the machining tolerance shall be considered to be within the scope of the protection of the present.

[0039] Referring to FIG. 26 or 27, the low-pressure chamber 431 includes a first low-pressure sub-chamber 4311' and a second low-pressure sub-chamber 4312'. The first rotor 41 has a first mating portion 411 that meshes with the second rotor 42. In the circumferential direction of the first rotor assembly 4, the first low-pressure sub-chamber 4311' and the second low-pressure sub-chamber 4312' are located on opposite sides of the first mating portion 411. The pressure in the first low-pressure sub-chamber 4311' is greater than that in the second low-pressure sub-chamber 4312'. Referring to FIGS. 31 to 38, in the radial direction of the first rotor assembly 4, the second branch channel 13' is in communication with the second low-pressure sub-chamber. With this arrangement, the pressure difference between the working medium in the second chamber 30 and that in the low-pressure chamber 431 can be relatively increased, enabling the working medium to effectively flow into the second chamber 30 and come into contact with the stator assembly 5 (or the stator assembly 5 and control assembly 8) located within the second chamber 30, thereby facilitating heat dissipation from the stator assembly 5 (or the stator assembly 5 and control assembly 8).

[0040] Referring to FIGS. 31 to 38, the electric pump includes a second inlet channel 12', which passes through the pump cover 1 from the upper surface to the lower surface of the pump cover 1 and is in communication with the first chamber 20 (or the low-pressure chamber 431). The first inlet channel 11' passes through the pump cover 1 from the upper surface to the lower surface of the pump cover 1. The second inlet channel 12', which is in communication with the first chamber 20, and the first inlet channel 11', which is in communication with the second chamber 30, are both provided on the pump cover 1, eliminating the need for providing additional inlet channels or inlets to be in communication with the second chamber 30. This contributes to the compact structure of a vehicle lubrication system. The pump cover 1 includes a recessed portion 14 that is recessed from the lower surface of the pump cover 1 towards the upper surface of the pump cover 1 along the axial direction of the pump cover 1 (or the axial direction of the electric pump). The recessed portion 14 does not extend through the upper surface of the pump cover 1. In the axial direction of the pump cover 1, there is a gap between the first end face of the first end 71' of the pump shaft 7 and the bottom wall of the recessed portion 14. The pump cover 1 includes a second branch channel 13' that extends from the sidewall of the recessed portion 14 towards the second inlet channel 12'. Part of the working medium within the second chamber 30 can enter the recessed portion 14 through the first channel 73. Along the radial direction of the pump cover 1, the second branch channel 13' extends through the circumferential sidewall of the recessed portion 14, thereby enabling communication between the recessed portion 14 and the second inlet channel 12'. The area of the flow cross section of the recessed portion 14 is greater than that of the second branch channel 13'. The flow cross section refers to the cross section perpendicular to the direction of liquid flow. According to the formula q = vA (where q is the flow rate, v is the fluid velocity, and A is the area of the flow cross section), in case of the same flow rate, the velocity of the working medium flowing within the recessed portion 14 is relatively low. Since the recessed portion 14 is in communication with the second chamber 30 through the first channel 73, the flow velocity of the working medium flowing into the first channel 73 from the second chamber 30 is also relatively reduced. This helps to extend the residence time of the working medium within the second chamber 30, thereby relatively increasing the flow rate of the working medium flowing in the second flow direction S2 shown in FIG. 31 within a certain time period and improving pump efficiency.

[0041] Referring to FIGS. 23 to 30, in the circumferential direction of the first rotor assembly 4, the front end 2011c is closer to the high-pressure chamber 432 than the rear end 2011d. The low-pressure chamber 431 is in communication with the second inlet channel 12'. The electric pump includes an outlet channel 15'. The low-pressure chamber 431 is not in communication with the outlet channel 15', whereas the high-pressure chamber 432 is in communication with the outlet channel 15'. The high-pressure chamber 432 is not in communication with the second inlet channel 12'. This arrangement helps prevent the working medium within the high-pressure chamber 432 from flowing back into the low-pressure chamber 431, thereby reducing flow losses and improving pump efficiency.

[0042] Referring to FIGS. 23 to 38, the electric pump includes a second inlet channel 12' and an outlet channel 15'. The outlet channel 15' is used for the outflow of the working medium. Specifically, the working medium can directly enter the low-pressure chamber 431 through the first inlet channel 11'. The working medium can exit the high-pressure chamber 432 through the outlet channel 15'. During one full rotation of the first rotor assembly 4, the volume of at least one hydraulic chamber 43 formed between an inner tooth of the first rotor 41 and the corresponding outer tooth of the second rotor 42 may change. Specifically, as the first rotor assembly 4 rotates from its starting position to a certain angle, the volume of at least one hydraulic chamber 43 formed between an inner tooth of the first rotor 41 and the corresponding outer tooth of the second rotor 42 gradually increases, creating a partial vacuum. At this point, the working medium is drawn into the low-pressure chamber 431 through the first inlet channel 11'. As the first rotor 41 and the second rotor 42 continue to rotate, the volume of at least one hydraulic chamber 43 formed between an inner tooth of the first rotor 41 and the corresponding outer tooth of the second rotor 42 gradually decreases, compressing the working medium. This enables the working medium within the hydraulic chamber 43 to be expelled into the outlet channel 15', thereby generating the motive force for flow.

[0043] In an embodiment, the electric pump is provided with a third channel (not shown). The third channel extends through the chamber wall 201 from the upper surface to the lower surface of the chamber wall 201. Part of the working medium within the second chamber 30 flows into the low-pressure chamber through the third channel The pressure at the inlet of the second channel 16 is greater than the pressure at the outlet of the third channel This creates a pressure difference of the working medium between the inlet of the second channel 16 and the outlet of the third channel. According to the principle that the working medium flows from areas with high pressure to areas with low pressure, the working medium within the second chamber 30 can flow towards the outlet of the third channel In other words, part of the working medium within the second chamber 30 can enter the low-pressure chamber 431 through the third channel Since the stator assembly 5 (or both the stator assembly 5 and the control assembly 8) is located within the second chamber 30, the flowing working medium can carry away at least part of the heat from the stator assembly 5 (or both the stator assembly 5 and the control assembly 8), thereby improving the heat dissipation efficiency of the stator assembly 5 (or both the stator assembly 5 and the control assembly 8). The low-pressure chamber 431 includes a first low-pressure sub-chamber 4311' and a second low-pressure sub-chamber 4312'. The first rotor 41 has a first mating portion 411 that meshes with the second rotor 42. In the circumferential direction of the first rotor assembly 4, the first low-pressure sub-chamber 4311' and the second low-pressure sub-chamber 4312' are located on opposite sides of the first mating portion 411. The pressure in the first low-pressure sub-chamber 4311' is greater than that in the second low-pressure sub-chamber 4312'. In the axial direction of the electric pump, the third channel is oriented towards the second low-pressure sub-chamber 4312'. This can relatively increase the pressure difference for the working medium entering the second chamber 30, enabling the working medium to effectively flow into the second chamber 30 and come into contact with the stator assembly 5 (or both the stator assembly 5 and the control assembly 8) located within the second chamber 30, thereby facilitating heat dissipation from the stator assembly 5 (or both the stator assembly 5 and the control assembly 8).

[0044] It should be noted that, the above embodiments are only intended to illustrate the present application rather than to limit the technical solutions described in the present application. Although the present specification has been described in detail with reference to the embodiments as described above, it should be understood by those skilled in the art that modifications or equivalent substitutions may still be made by those skilled in the art to the technical solutions of the present application, and all technical solutions and improvements thereof that do not depart from the spirit and scope of the present application shall be included within the scope of the claims of the present application.

Claims

1. An electric pump, comprising: a first rotor assembly (4) and a second rotor assembly (6), wherein the first rotor assembly (4) comprises a first rotor (41) and a second rotor (42), and the first rotor (41) is positioned outside of the second rotor (42); a first chamber (20) and a second chamber (30), wherein the first rotor assembly (4) is located in the first chamber (20), the second rotor assembly (6) is located in the second chamber (30), and the first rotor assembly (4) is in transmission connection to the second rotor assembly (6); a first accommodation portion (9) comprising a bottom wall (91); a first channel (40) extending through the bottom wall (91) from an upper surface to a lower surface of the bottom wall (91); a hydraulic chamber (43) located between the first rotor (41) and the second rotor (42), and comprising a low-pressure chamber (431); and a first inlet channel (11) that communicates with the low-pressure chamber (431), wherein the low-pressure chamber (431) communicates with the first channel (40), and the first channel (40) communicates with the second chamber (30).

2. The electric pump according to claim 1, wherein the low-pressure chamber (431) comprises a first low-pressure sub-chamber (431a) and a second low-pressure sub-chamber (431b), the first rotor (41) has a first mating portion (41a) that meshes with the second rotor (42), the first low-pressure sub-chamber (431a) and the second low-pressure sub-chamber (431b) are located on opposite sides of the first mating portion (41a) in a circumferential direction of the first rotor assembly (4), the first channel (40) comprises a first sub-portion facing and communicating with the first low-pressure sub-chamber (431a), and a second sub-portion facing and communicating with the second low-pressure sub-chamber (431b), and a pressure in the first low-pressure sub-chamber (431a) is greater than that in the second low-pressure sub-chamber (431b).

3. The electric pump according to claim 2, wherein the hydraulic chamber (43) comprises a high-pressure chamber (432), and the first channel (40) comprises: a first sidewall (401) and a second sidewall (402), wherein the first sidewall (401) is closer to a central axis of the second rotor (42) than the second sidewall (402) in a radial direction of the first rotor assembly (4), and a first front end (405) and a first rear end (406), wherein the first front end (405) is farther from the high-pressure chamber (432) than the first rear end (406) in the circumferential direction of the first rotor assembly (4), and a distance between the first sidewall (401) and the second sidewall (402) in a direction perpendicular to the central axis of the second rotor gradually increases from the first rear end (406) to the first front end (405).

4. The electric pump according to claim 2 or 3, wherein the first channel (40) comprises a first front end (405) and a first rear end (406), the first front end (405) is farther from the high-pressure chamber (432) than the first rear end (406) in the circumferential direction of the first rotor assembly (4), and the first rotor (41) has a second mating portion (41b) that meshes with the second rotor (42), the second mating portion (41b) is closer to a high-pressure chamber (432) than the first mating portion (41a) in the circumferential direction of the first rotor assembly (4), and the first front end (405) is located between the first mating portion (41a) and the second mating portion (41b).

5. The electric pump according to claim 4, wherein the first front end (405) comprises an extension portion (405a), the first rotor (41) has a third mating portion (41c) that meshes with the second rotor (42), the low-pressure chamber (431) and the high-pressure chamber (432) are located on opposite sides of the third mating portion (41c) in the circumferential direction of the first rotor assembly (4), and the extension portion (405a) is closer to the second mating portion (41b) than the third mating portion (41c).

6. The electric pump according to claim 4, further comprising a second channel (50), wherein the second channel (50) extends through the bottom wall (91) from the upper surface to the lower surface of the bottom wall (91), the second channel (50) communicates with the low-pressure chamber (431) and also with the second chamber (30), the first rotor (41) has a third mating portion (41c) that meshes with the second rotor (42), the low-pressure chamber (431) and the high-pressure chamber (432) are located on opposite sides of the third mating portion (41c) in the circumferential direction of the first rotor assembly (4), and the second channel (50) is closer to the third mating portion (41c) than the first front end (405).

7. The electric pump according to claim 2, wherein the first channel (40) comprises a first sidewall (401) and a second sidewall (402), the low-pressure chamber (431) comprises a first chamber wall (4311) and a second chamber wall (4312), the first chamber wall (4311) is the farthest from the central axis of the first rotor (41) in a radial direction of the first rotor (41), the second chamber wall (4312) is the closest to the central axis of the second rotor (42) in a radial direction of the second rotor (42), in a radial direction of the first rotor assembly (4), the first sidewall (401) is closer to the central axis of the second rotor (42) than the second sidewall (402) and is closer to the central axis of the first rotor (41) than the first chamber wall (4311), and the second sidewall (402) is further from the central axis of the second rotor (42) than the second chamber wall (4312).

8. The electric pump according to claim 3, wherein the low-pressure chamber (431) comprises a first chamber wall (4311) and a second chamber wall (4312), the first chamber wall (4311) is the farthest from the central axis of the first rotor (41) in a radial direction of the first rotor (41), the second chamber wall (4312) is the closest to the central axis of the second rotor (42) in a radial direction of the second rotor (42), and in the radial direction of the first rotor assembly (4), the first sidewall (401) of the first channel (40) is closer to the central axis of the second rotor (42) than the second sidewall (402) of the first channel (40) and is closer to the central axis of the first rotor (41) than the first chamber wall (4311), and the second sidewall (402) of the first channel (40) is farther from the central axis of the second rotor (42) than the second chamber wall (4312).

9. The electric pump according to any one of claims 1 to 8, comprising a pump cover (1), a driving shaft (7), and a third channel (60), wherein the second rotor assembly (6) is configured to drive the second rotor (42) to rotate via the driving shaft (7), the first inlet channel (11) extends through the pump cover (1) from an upper end face to a lower end face of the pump cover (1), the third channel (60) extends through the driving shaft (7) from a first end face (71) to a second end face (72) of the driving shaft (7), the first inlet channel (11) communicates with the third channel (60), the third channel (60) communicates with the second chamber (30), and the electric pump is configured to, when the electric pump is in operation, allow part of working medium to enter the low-pressure chamber (431) through the first inlet channel (11), and enable a pressure of the working medium at an inlet of the third channel (60) to be greater than that at an outlet of the first channel (40), thus enabling the working medium to exit the second chamber (30) through the first channel (40).

10. The electric pump according to any one of claims 1 to 8, comprising a pump cover (1), a driving shaft (7), a second inlet channel (15), and a third channel (60), wherein the second rotor assembly (6) is configured to drive the second rotor (42) to rotate via the driving shaft (7), the second inlet channel (15) extends through the pump cover (1) from an upper end face to a lower end face of the pump cover (1), the third channel (60) extends through the driving shaft (7) from a first end face (71) to a second end face (72) of the driving shaft (7) and communicates with the second chamber (30), and the electric pump is configured to, when the electric pump is in operation, allow part of working medium to enter the third channel (60) from the second inlet channel (15), and enable a pressure of the working medium at an inlet of the third channel (60) to be greater than that at an outlet of the first channel (40).

11. The electric pump according to any one of claims 1 to 8, comprising a pump cover (1), a second inlet channel (15), a chamber wall (101), and a fourth channel (70), wherein the second inlet channel (15) extends through the pump cover (1) from an upper end face to a lower end face of the pump cover (1), the fourth channel (70) extends through the chamber wall (101) from an upper end face to a lower end face of the chamber wall (101), such as to allow part of working medium within the second inlet channel (15) to enter the second chamber (30) through the fourth channel (70), and the electric pump is configured to, when the electric pump is in operation, a pressure of the working medium at an inlet of the fourth channel (70) is greater than that at an outlet of the first channel (40), thus enabling the working medium to exit the second chamber (30) through the first channel (40).

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