Electronic oil pump

Abstract

The present application discloses an electronic oil pump comprising a pump housing and also: a stationary shaft provided in the pump housing; an internal gear eccentrically and rotatably connected to the stationary shaft; an external gear coaxially connected to the stationary shaft and rotatably connected in the pump housing, wherein the external gear is arranged on the outer circumference of the internal gear and can mesh with the internal gear; a motor rotor fixedly connected to the outer circumference of the external gear; a motor stator located on the outer circumference of the rotor and fixedly connected to the pump housing; wherein the projected surfaces of the motor stator, the motor rotor, the external gear, the internal gear, and the stationary shaft can overlap at least partially on a plane that can pass through the center of the axis of the stationary shaft.Due to the use of small shaft bearings, the electronic oil pump provided in the present application offers the advantages of low height, a compact structure, low resistance and high stability.

Description

TECHNICAL FIELDThe present application relates to the technical field of electronic oil pumps for new energy vehicles, in particular to an electronic oil pump with low resistance and high stability.PRIOR ARTWith the rapid development of automotive electronics and new energy vehicles, integrated high precision electronic oil pumps are increasingly being used because of their high efficiency, energy conservation, and flexible control.At present, an electronic oil pump is mainly composed of three parts: a rotor pump, an engine, a controller, and other components, the controller controls the operation of the engine and then drives the rotor pump to rotate to realize the operation of the electronic oil pump.However, existing electronic oil pumps have defects such as a complex structure, a large volume, a high resistance, and a low stability, so that there is still a lot of room for improvement.CONTENT OF THE PRESENT APPLICATIONThe purpose of the present application is to provide an electronic oil pump that offers advantages of a compact structure, a small volume, a low resistance, a good stability, and a high working efficiency.The present application provides an electronic oil pump comprising a pump housing and also:a fixed shaft provided in the pump housing;an internal gear eccentrically and rotatably connected to the fixed shaft;an external gear coaxially connected to the fixed shaft and rotatably connected in the pump housing, the external gear being disposed on the outer periphery of the internal gear and being capable of meshing with the internal gear;a motor rotor fixedly connected to the outer periphery of the external gear;a motor stator located on the outer periphery of the rotor and fixedly connected to the pump housing;wherein the projected areas of the motor stator, the motor rotor, the external gear, the internal gear and the fixed shaft may at least partially overlap on a plane that may pass through the axis center of the fixed shaft.By adopting the above technical solution, an external gear is provided in the motor rotor, so that the external gear is integrated into the motor rotor and integrated integrally. Such a construction has the following advantages. First, the height of the electronic oil pump is reduced, which significantly reduces system volume and weight and significantly reduces the material and production costs of the system. Secondly, the height of the oil pump is reduced, which shortens the path of the pressurized cooling oil, effectively reduces friction in the space of the rotor pump, and contributes to improvement of the system efficiency. Third, the structure is simple, reducing the cumulative mounting error, improving the coaxiality of the motor rotor, the motor stator and the external gear, and effectively avoiding the hidden risk of air gap eccentricity. Fourth, the structure is more stable, thereby effectively reducing vibration noise in operation of the pump body, improving performance of the pump body, improving reliability of the pump body, and prolonging the service life of the pump body.In some embodiments, it also includes a first shaft bearing, wherein the external gear is rotatably connected to one end of the fixed shaft via the first shaft bearing, wherein the other end of the fixed shaft is connected to the pump housing.In some embodiments, it also includes a second shaft bearing, one end of the fixed shaft being rotatably connected to the pump housing via the second shaft bearing, the other end of the fixed shaft being coaxially connected to the external gear.Conventional installation of the fixed shaft and the pump housing is achieved by forming steps on the underside of the pump housing, the fixed end of the fixed shaft passing through the respective step and being screwed to the nut, and the nut can abut the end face of the step, the fixed connection between the fixed shaft and the pump housing being achieved by the frictional force generated by the abutment of the nut on the step. However, the strength of the assembled nut affects the axial end face gap of the pump body. In the working state, the temperature inside the pump housing rises. Due to the difference in thermal expansion coefficients of the materials of the pump housing, the fixed shaft, and the nut (e.g., aluminum material of the pump housing, stainless steel material of the fixed shaft, and steel material of the nut), the end face gap changes, and thereby the performance of the pump body is impaired. By adopting the above technical solution, the shaft bearing is directly connected to the fixed shaft, thereby reducing the aspect ratio of the electronic oil pump. A large-diameter shaft bearing has a large aspect ratio to the rotating shaft, so that the structural stability of the electronic oil pump is poor, resulting in poor concentricity of the motor and the pump gear relative to the rotating shaft when the electronic oil pump is in operation. Changing to a smaller journal bearing mounted on the bottom of the rotating shaft offers many advantages. For example, the pump body structure system has a smaller aspect ratio, the pump body structure is more stable, and concentricity of the motor, pump gear, and rotation shaft can be effectively improved. Second, it greatly simplifies the assembly difficulties of the gear pump structure, the rotary shaft, and the pump body housing, which contributes to securing concentricity of the structure of the pump body system and improving the air gap accuracy of the motor stator and the motor rotor, so that the motor can always operate in a precise and uniform magnetic field distribution, whereby the motor will operate more stably and the magnetic field of the motor is utilized more efficiently, which ultimately ensures highly efficient operation of the electronic oil pump. Third, the large area contact interface between the large shaft bearing and the external gear of the gear pump and the pump body housing is reduced, and the accumulation of assembly deviations caused by multiple contact interfaces is reduced, thereby effectively reducing the frictional resistance that arises when the pump body structure rotates, and reducing the problem of large centrifugation caused by the rotation of large bearings, thereby reducing the influence of temperature-related thermal expansion of various materials on the axial and radial end face gaps of the pump body and improving the stability and efficiency of the electronic oil pump.In some implementations, the electronic oil pump further includes an eccentric calibration component located between the fixed shaft and the internal gear, the eccentric calibration component is a crescent sleeve disposed on the circumferential outer wall of the fixed shaft, the crescent sleeve being provided with an arc-shaped groove for embedding the fixed shaft, the crescent sleeve being provided so that the internal gear is eccentrically rotatably connected to the fixed shaft. Preferably, it is provided that the crescent sleeve is firmly connected to the pump housing.By adopting the above technical solution, the eccentric calibration component can compensate for the concentricity deviation of a plurality of parts such as the pump housing, the fixed shaft, and the motor due to processing and assembly, thereby effectively ensuring concentricity of the pump housing, the fixed shaft, and the motor. While the external gear is rotatably connected to the fixed shaft, the eccentric assembly may be rotatably connected to the internal gear, thereby achieving the coaxial and eccentric effect of the internal gear and the external gear. Since the fixed shaft and the pump casing are concentrically arranged at the same time, the motor rotor can attain high concentricity with the fixed shaft and the pump casing by means of the fixed shaft, thereby effectively compensating for the problem of insufficient concentricity arising from tolerance accumulation in processing and assembly. The circumferential side wall of the fixed shaft is partially embedded in the arcuate groove such that the circumferential side wall of the fixed shaft and the circumferential outer wall of the crescent sleeve form an eccentric assembly rotatably connected to the internal gear. This achieves the coaxial and eccentric effect of the internal gear and the external gear, effectively compensating for the problem of insufficient eccentricity between the motor circle center and the axle center due to the accumulation of tolerances in processing and assembly, and also maintaining the mutual drive between the internal gear and the external gear of the rotor pump due to the centrifugal construction.In some embodiments, it also comprises a shaft sleeve, wherein the internal gear is rotatably connected to the crescent sleeve and the fixed shaft via the shaft sleeve.By adopting the above technical solution, the shaft sleeve can reduce friction between the internal gear, the fixed shaft, and the crescent sleeve, reduce frictional resistance, and improve rotation efficiency.In some embodiments, it is provided that a plurality of oil passage chambers are formed enclosed between the external gear and the internal gear, the volume of each oil passage chamber may increase stepwise first along the rotational direction of the external gear, and then decrease stepwise, the pump housing is provided with an oil inlet bore and an oil outlet bore, the oil inlet of the oil passage chamber may correspond to the oil inlet bore as the oil passage chamber increases stepwise, the oil outlet of the oil passage chamber may correspond to the oil outlet bore as the oil passage chamber decreases stepwise.In some implementations, it is provided that the cooling oil can flow through the oil inlet bore into the oil passage chamber when the oil passage chamber gradually increases, wherein the cooling oil in the oil passage chamber is pushed out of the oil outlet bore when the oil passage chamber gradually decreases.By adopting the above technical solution, the circumferential side wall of the external gear inner circle, the inner end surface of the external gear outer circle, and the circumferential outer wall of the internal gear can be formed to be enclosed into a plurality of closed oil passage chambers. When the internal gear and the external gear rotate relative to each other, the oil passage chamber may receive oil through the oil inlet bore as the oil passage chamber gradually increases, with the amount of oil in the oil passage chamber increasing as the volume increases. During oil collection, the lower temperature oil comes into contact with the teeth of the internal gear and the external gear, and the oil absorbs the heat of the teeth. In the process of reducing the oil passage chamber stepwise, oil can be discharged through the oil discharge bore, the amount of oil in the oil passage chamber decreases with decreasing volume, the oil having a higher temperature after heat absorption during oil absorption is discharged from the pump body through the oil discharge bore, thereby achieving cooling and lubrication of the internal gear and the external gear, and cooling of the pump body, thus ensuring the working temperature and efficiency of the pump.In some embodiments, it also includes a circuit control module, the circuit control module including a controller and a hub disposed in the pump housing, the motor stator being disposed on the hub, the motor stator being provided with a plurality of stator windings along its circumferential direction, the motor rotor being seated on the circumferential outer circle of the external gear, the circumferential outer wall of the motor rotor corresponding to the circumferential side wall of the motor stator.By adopting the above technical solution, the controller controls the stroke to supply current to a plurality of stator windings on the motor stator. When the plurality of stator windings are energized, the generated magnetic field interacts with the permanent magnet field of the rotor magnet to rotate the motor rotor, the motor rotor being integrated with the outer rotor of the gear pump, i.e., the motor stator and the rotor magnet cooperate to rotate the outer gear of the rotor gear pump, the outer gear of the rotor gear pump then driving the inner gear to rotate, thereby achieving relative rotation between the inner gear and the outer gear.In some embodiments, an O-ring seal is also provided around the pump housing.In one technical solution, an O-ring seal can be used for horizontal and axial deformation, which can have an advantageous effect on the seal, can reduce oil leakage and high pressure formation, is cost-effective, simple to assemble, has a long service life and is easy to maintain.In summary, at least one of the following advantageous technical effects can be obtained with the present application: 1. in the electronic oil pump of the present application, the height of the electronic oil pump is reduced, the system volume is reduced, the weight is reduced, and the cost is lowered. The structure is simple, the assembly precision is high, the working efficiency is high, and the life of the product is prolonged. 2. the electronic oil pump in some embodiments of the present application has a smaller aspect ratio, the pump body structure is more stable, and concentricity between the motor, the pump gear, and the rotation shaft can be effectively improved. With this construction, the assembly difficulties of the gear pump structure, the rotary shaft, and the pump body housing can be significantly reduced, which helps ensure concentricity of the structure of the pump body system and significantly improve the air gap accuracy of the motor stator and the motor rotor, so that the motor can always operate in a precise and uniform magnetic field distribution, whereby the motor will operate more stably and precisely and the magnetic field of the motor is used more efficiently, which ultimately ensures highly efficient operation of the electronic oil pump. 3. When a second shaft bearing is used, the bearing size is reduced, thereby reducing the area of the contact interface between the shaft bearing and the external gear of the gear pump and the pump body housing, and the accumulation of assembly deviations caused by a plurality of contact interfaces is reduced, thereby effectively reducing the frictional resistance that arises when the pump body structure rotates, and reducing the problem of large centrifugation caused by the rotation of large bearings, thereby improving the efficiency of the electronic oil pump and improving the stability of the electronic oil pump. 4. by the arrangement of the second shaft bearing, the lower surface of the rotary shaft and the pump body housing are integrally fixed with the upper portion of the shaft directly connected to the upper cover of the external gear to ensure a precise end face gap and a precise radial gap of the pump body, thereby avoiding the thermal expansion effect caused by temperature changes due to different material temperature coefficients of different portions. Meanwhile, by the arrangement of the second shaft bearing, the structure of the electronic pump becomes more stable, thereby effectively reducing the vibration noise in the operation of the pump body and improving the NVH performance of the pump body, thereby improving the reliability of the pump body and extending the life of the pump body.BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1 is a schematic structural appearance diagram of the first embodiment of the electronic oil pump of the present application; FIG. 2 is a three-dimensional schematic structural sectional view of the first embodiment of the electronic oil pump of the present application; FIG. 3 is an internal structural schematic diagram of the first embodiment of the electronic oil pump of the present application; FIG. 4 is a structural schematic diagram of the motor stator of the first embodiment of the electronic oil pump of the present application; FIG. 5 is a structural schematic diagram of the pump housing of the first embodiment of the electronic oil pump of the present application; FIG. 6 is a three-dimensional schematic sectional view of the second embodiment of the electronic oil pump of the present application; FIG. 7 is a structural schematic diagram of the circuit control module, the external gear, and the internal gear of the second embodiment of the electronic oil pump of the present application; FIG. 8 is a structural schematic coordination diagram of the motor stator, the internal gear, and the external gear of the second embodiment of the electronic oil pump of the present application; FIG. 9 is a schematic structural diagram of the pump casing lower surface of the second embodiment of the electronic oil pump of the present application; FIG. 10 is a structural schematic diagram of the external gear and the internal gear of the second embodiment of the electronic oil pump of the present application; FIG. 11 is a structural schematic diagram of the eccentric calibration component of the second embodiment of the electronic oil pump of the present application; FIG. 12 is a three-dimensional schematic sectional view of the third embodiment of the electronic oil pump of the present application.Explanation of the reference numerals: 1. pump housing; 11. oil inlet bore; 12. oil outlet bore; 13. underside of pump housing; 131. Fixing hole; 132. Oil receiving opening; 133. Oil outlet opening; 134. Separating portion; 135. Mounting guide hole; 14. filter screen; 15. housing; 16. air gap; 17. seal ring; 2. external gear; 21. oil passage chamber; 22. motor rotor neck portion; 23. external gear inner circle; 24. motor rotor outer circle; 25. top cover; 26. sensor; 3. internal gear; 4. fixed shaft; 41. eccentric assembly; 5. eccentric calibration component; 51. arcuate groove; 52. positioning hole; 6.Shaft bearing; 7th shaft sleeve; 8th motor rotor; 9th circuit control module; 91th controller; 92nd stroke; 93th motor stator; 94th stator winding.DETAILED DESCRIPTIONIn order to make the purpose, the technical solutions, and the advantages of the embodiments of the present invention clearer, the present invention will be further described below in detail in conjunction with the accompanying drawings. The components of the embodiments of the present invention described and illustrated in the figures herein can be arranged and configured in a wide variety of different configurations in general. All other embodiments which the person skilled in the art obtains without any creative action on the basis of the embodiments in the present invention are within the scope of protection of the present invention.Note that like reference numerals and letters in the following drawings represent like elements. Thus, once an element is defined in a drawing, no further definition and explanation is required in the following drawings.In describing the present invention, unless otherwise specified and limited, the terms "installation", "connection", "connection" or the like are to be broadly understood, for example, it may be a fixed connection or a detachable connection or integral connection; it may be a mechanical or electrical connection; it may be a direct connection or an indirect connection via an interposed medium; and it may be an internal communication of two elements. Those skilled in the art can understand the specific meanings of the above terms in the present invention according to specific situations.In describing the present application, it should be understood that the orientations or positional relationships indicated by the terms "upper", "lower", "left", "right" and the like are the shown orientations or positional relationships based on the drawings and are for convenience of description of the present application and convenience of description only, rather than indicating or implying that said device or element has a particular orientation or orientation or must be constructed and operated in a particular orientation, and therefore should not be construed as limiting the present application.The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Features in the embodiments described below may be combined with each other without conflict.First EmbodimentReferring to FIGS. 1 to 5, the present embodiment discloses an electronic oil pump. Referring to FIG. 1, the electronic oil pump includes a pump housing 1. in some embodiments, the pump housing 1 is made of aluminum. An oil outlet bore 12 is provided on the side wall of the pump housing 1, and an oil inlet bore 11 is provided on the underside of the pump housing 1, wherein a filter screen 14 is provided on the underside of the pump housing 1, which filter screen is located on the oil inlet bore 11 and covers the oil inlet bore 11.Referring to FIGS. 2 to 4, the fixed shaft 4, the motor, the circuit control module 9, and the gear set are mounted in the pump housing 1. The motor comprises a motor rotor 8, a motor stator 93 and stator windings 94. the motor stator 93 is fixed in the pump housing 1 and the motor rotor 8 is located in the motor stator 93, the stator windings 94 consisting of several groups and being wound around the motor stator 93 in a circular arrangement between the motor rotor 8 and the motor stator 93.The gear set includes an external gear 2 integrated and fixed with the motor rotor 8, and an internal gear 3 located inside the external gear 2 and meshed with the internal teeth of the external gear 2. The internal gear 3 is eccentrically rotatably connected to the fixed shaft 4, and the eccentricity means that the rotation axes do not coincide with each other. The external gear 2 is coaxially connected to the fixed shaft 4 and rotatably connected in the pump housing 1. The external gear 2 of the present invention is integrated with the motor rotor 8 and integrally pressed. On the one hand, such a design significantly reduces the volume and weight of the system and significantly reduces the material and production costs of the system; on the other hand, the friction in the space of the rotor pump is effectively reduced, which has a positive effect on improving the system efficiency.The pump casing 1 is provided with a casing 15 for separating the controller 91 and the stroke 92, which casing separates the oil pipe and the electronic control part, can improve the sealing, and can ensure that the controller 91 operates at an appropriate temperature. Mounted on the housing 15 is a PTC temperature sensor (not marked in the figure) for detecting and feedback of the cooling oil temperature, the PTC temperature sensor being electrically connected to the controller 91. In some implementations, the PTC temperature sensor may achieve an oil temperature sensing accuracy of 0.1° C.Since the external gear is integrated into the motor rotor, the thermal expansion coefficients of the motor stator 93 and the pump body are consistent, thereby significantly reducing the influence of the temperature on the oil pump gap, accurately ensuring the pump end face gap, and effectively reducing or avoiding the influence of the temperature on the flow efficiency of the system.During operation, the circuit control module 9 controls energization of the plurality of stator windings 94, and then the generated magnetic field interacts with the permanent magnetic field of the magnet of the motor rotor 8 to rotate the motor rotor 8. The motor rotor 8 is fixed to the external gear 2, that is, the magnets of the motor stator 93 and the motor rotor 8 cooperate to rotate the external gear 2, and the external gear 2 in turn drives the internal gear 3 to rotate, thereby achieving relative rotation between the internal gear 3 and the external gear 2.Specifically, the projected areas of the motor stator 93, the motor rotor 8, the external gear 2, the internal gear 3, and the fixed shaft 4 may at least partially overlap on a plane that may pass through the axis center of the fixed shaft 4. This structure can reduce the axial height of the electronic oil pump and has a compact structure and a small volume.On the outer periphery of the pump housing 1, a sealing ring is additionally provided. In some embodiments, the seal ring is an O-ring seal 17 made of rubber. For horizontal and axial deformation, an O-ring seal 17 can be used, which has an advantageous effect on the seal, can reduce oil leakage and high-pressure formation, is cost-effective, simple to install, has a long life and is easy to maintain.In some embodiments, the electronic oil pump also includes an upper cover 25 fixedly connected to the external gear 2, one end of the fixed shaft 4 is rotatably connected to the pump housing 1 via the shaft bearing 6, and the other end of the fixed shaft 4 is coaxially and fixedly connected to the external gear 2 via the upper cover 25. The internal gear 3 is eccentrically connected to the fixed shaft 4 via the pump housing 1, and the internal gear 3 is rotatably connected to the pump housing 1.In order to cold start the high-performance electronic oil pump, a sensor 26, for example, a magnetic transformer, is fixedly connected to the upper surface of the fixed shaft 4 in this embodiment. In other embodiments, the sensor 26 may also be fixedly connected to the top cover 25 which is fixedly connected to the external gear 2.The circuit control module 9 includes a stroke 92 provided in the pump housing 1 and located above the motor and a controller 91 located above the stroke 92. The function of the hub 92 is to collect the incoming and outgoing wires of the stator winding 94 so that the distribution of the wire ends is regular and clear, and the wire ends are welded to the hub 92, making the process simple and refreshing. Another function of the stroke 92 is to disconnect the controller 91 and the engine part, and in this way the oil circulates only in the engine part and forms a cooling and lubrication circuit without the oil entering the controller 91.Above the stator arrangement, a stroke 92 is provided. The pins of the stator winding 94 are routed through the hub 92, which simplifies the design of the electronic control component and simplifies the conventional winding design.The controller 91 can achieve a quick response, has characteristics such as shift polarity prevention, prevents signal interference, monitors oil temperature, prevents overtemperature, has an independent communication channel, detects motor angular position, receives and calculates motor speed, and compares and feedback controls actual rotor speed.In the present embodiment, since the height of the entire electronic oil pump is reduced as compared with the conventional electronic oil pump, the time required for the pressurized cooling oil to flow to the stator assembly is shorter and the cooling effect is better.Referring to FIG. 2, the operation process of the electronic oil pump is: the controller 91 controls the stroke 92 to supply power to the plurality of stator windings 94 on the motor stator 93. After the plurality of stator windings 94 are energized, they generate a magnetic field to drive the motor rotor 8 to rotate, and the motor stator 93 drives the external gear 2 to rotate, thereby realizing relative rotation between the external gear 2 and the internal gear 3.When the internal gear 3 and the external gear 2 rotate relative to each other, the oil passage chamber of the chamber 21 gradually increases, and oil is received through the oil inlet hole 11, so that the amount of oil in the oil passage chamber 21 increases as the volume increases. In this case, during oil storage, the lower temperature oil comes into contact with the teeth of the internal gear 3 and the external gear 2, and the oil absorbs the heat of the teeth. Then, in the process of gradually decreasing the oil passage chamber 21, oil is discharged through the oil discharge bore 12, and the amount of oil in the oil passage chamber 21 decreases as the volume decreases. In this case, the oil having a higher temperature after the heat absorption during the oil absorption is discharged from the pump body through the oil discharge hole 12, thereby achieving the cooling and lubrication of the internal gear 3 and the external gear 2, and also achieving the temperature of the pump body.Referring to FIG. 5, the bottom surface of the pump housing 1 is integrally formed with a bottom surface 13 of the pump housing that can cover the oil inlet bore 11 and the oil outlet bore 12. A fixing hole 131 is provided at the bottom of the pump housing 1, and the fixing hole 131 is disposed eccentrically to the pump housing 1. The fixed shaft 4 is provided in the fixing hole 131, and the circumferential outer wall of the fixed shaft 4 closely fits the hole wall of the fixing hole 131. In order to reduce the rotational resistance and to increase the service life, a slide bearing may be provided between the internal gear 3 and the pump housing 1. The end face of the pump casing lower surface 13 is provided with an oil receiving hole 132 communicating with the oil inlet bore 11 and an oil discharge hole 133 communicating with the oil outlet bore 12. The pump casing lower surface 13 is provided with a partitioning portion 134 for partitioning the oil receiving hole 132 and the oil discharge hole 133, and a side of the partitioning portion 134 can abut against a side of the internal gear 3 to improve sealing performance between the oil receiving hole 132 and the oil discharge hole 133.In this embodiment, the eccentric fit between the internal gear 3 and the external gear 2 is achieved by the eccentric mounting hole 131 of the pump housing without unnecessary accessories. The advantage of this construction is that the gear pump structure is simplified and assembly difficulties of the rotary shaft and the pump body housing are reduced; concentricity between motor, housing and gear set is improved, which helps ensure structural concentricity of the pump body system; the air gap between motor stator and motor rotor is increased so that the motor always operates in a precise and uniform magnetic field distribution; the motor operates more stably and precisely and uses the magnetic field of the motor more efficiently, ultimately ensuring highly efficient operation of the electronic oil pump; the accumulation of assembly deviations caused by multiple contact interfaces is reduced, thereby effectively reducing the frictional resistance that arises as the pump body structure rotates; The larger centrifugation caused by the rotation of the large shaft bearing is reduced, improving the efficiency of the electronic oil pump and improving the stability of the electronic oil pump; the size is small, the weight is small, and the cost is low.Second EmbodimentReferring to FIGS. 6 to 11, the present embodiment is different from the first embodiment in terms of the eccentric connection structure of the fixed shaft 4.Referring to FIGS. 6 to 8, the external gear 2 in this embodiment includes an external-gear inner circle 23 that meshes with the internal gear 3, and the motor rotor inner circle is fixedly fitted on the external-gear outer circle. The permanent magnet of the motor rotor 8 is fastened to the outer periphery of the motor rotor outer circle 24, wherein an air gap 16 is provided between the permanent magnet of the motor rotor 8 and the stator winding 94. During the research and development process, it is necessary to minimize the influence of various factors on the stability of the spacing of the air gap 16. The top of the motor rotor outer circle 24 is integrally formed with a motor rotor neck portion 22, and the shaft bearing 6 is mounted in the motor rotor neck portion 22. The ball bearing 6 supports the motor rotor 8 to ensure the rotation of the external gear 2 in the rotor pump, the ball bearing 6 being mounted on the end of the rotor pump so that there is no space between the motor and the rotor pump, thereby reducing the height of the electronic oil pump and significantly reducing the weight and volume of the rotor pump. In the present embodiment, the ball bearing 6 and the pump housing 1 are machined with the same mechanical melting apparatus, so that the two have very precise coaxiality and concentricity and can precisely control the air gap eccentricity.Referring to FIGS. 6 to 9, a mounting hole 131 is provided at the bottom of the pump housing 1, the mounting hole 131 being concentric with the pump housing 1. The fixing hole 131 is provided with a fixed shaft 4, and the fixed shaft 4 is closely fitted to the shaft bearing 6, one side of the external gear 2 being formed integrally with the motor rotor neck portion 22 fitting to the shaft bearing 6. The internal gear comprises an internal gear inner circle co-operating coaxially with the fixed shaft 4 and abutting the internal gear inner circle of the eccentric assembly, wherein the internal gear 3 is eccentrically rotatably connected to the fixed shaft 4 via the eccentric calibration component 5, wherein the eccentricity means that the rotation axes do not coincide with each other. The eccentric calibration component 5 is a crescent sleeve disposed on the circumferential outer wall of the fixed shaft 4, the crescent sleeve being provided with an arcuate groove 51 for embedding the fixed shaft 4, the crescent sleeve being provided so that the internal gear 3 is eccentrically rotatably connected to the fixed shaft 4. The motor rotor inner circle is axially arranged to abut against the external gear outer circle. A motor rotor outer circle 24 side is integrally formed with a motor rotor neck portion 22 that fits the journal bearing 6, the motor rotor neck portion 22 and a motor rotor outer circle 24 side may form an embedding groove for the journal bearing 6 to be embedded, the circumferential outer wall of the journal bearing 6 closely fits the circumferential groove wall of the embedding groove, which may reduce the operating noise.Referring to FIGS. 9-11, the circumferential side wall of the external gear inner circle 23 and the circumferential outer wall of the internal gear 3 may abut on the inner end surface of the motor rotor outer circle 24, respectively, a plurality of closed oil passage chambers 21 are formed between the external gear 2 and the internal gear 3 by regional division by tooth-to-tooth contact, the volume of each oil passage chamber 21 may increase stepwise along the rotational direction of the external gear 2 first and then decrease stepwise, the bottom surface of the pump housing 1 is formed integrally with an oil inlet bore 11, and the circumferential outer wall is formed integrally with an oil outlet bore 12. The oil inlet of the oil passage chamber 21 may correspond to the oil inlet bore 11 when the oil passage chamber 21 gradually increases, and the oil outlet of the oil passage chamber 21 may correspond to the oil outlet bore 12 when the oil passage chamber 21 gradually decreases.The bottom surface of the pump housing 1 is formed integrally with a pump housing bottom surface 13 capable of covering the oil inlet bore 11 and the oil outlet bore 12, and a fixing hole 131 fixedly connected to one end of the fixed shaft 4 is formed axially on the end surface of the pump housing bottom surface 13. The fixed shaft 4 is inserted into the fixing hole 131, and the circumferential outer wall of the fixed shaft 4 closely fits the hole wall of the fixing hole 131. In order to reduce the rotational resistance and to increase the service life, a slide bearing may be provided between the internal gear 3 and the pump housing 1. The end face of the pump casing lower surface 13 is provided with an oil receiving hole 132 communicating with the oil inlet bore 11 and an oil discharge hole 133 communicating with the oil outlet bore 12. The pump casing lower surface 13 is provided with a partitioning portion 134 for partitioning the oil receiving hole 132 and the oil discharge hole 133, and a side of the partitioning portion 134 can abut against a side of the internal gear 3 to improve sealing performance between the oil receiving hole 132 and the oil discharge hole 133.One side of the crescent sleeve is provided with a positioning hole 52. The pump casing lower surface 13 is provided with a mounting guide hole 135 corresponding to the positioning hole 52, the mounting guide hole 135 and the fixing hole 131 being eccentrically disposed, and a shaft sleeve 7 is provided between the fixed shaft 4 and the internal gear 3 for reducing sliding friction. The internal gear 3 is rotatably connected to the crescent sleeve and the fixed shaft 4 via the shaft sleeve 7.A hole is provided in the pump housing 1 to match the fixed shaft 4, which effectively reduces the machining complexity of the pump housing 1, improves the machining efficiency of the pump housing 1, and improves the accuracy of fitting of the external gear 2 and the internal gear 3.The principle of implementation of a highly precisely designed electronic oil pump in the embodiment of the present application is:In the pump housing 1, a fixed shaft 4 is provided, then an eccentric calibration component 5 is provided on the circumferential side wall of the fixed shaft 4 to form an eccentric assembly 41, so that while the external gear 2 is rotatably connected to the fixed shaft 4, the eccentric assembly 41 can also be rotatably connected to the internal gear 3, thereby achieving the coaxial and eccentric action of the internal gear 3 and the external gear 2.Third EmbodimentReferring to FIG. 12, the difference from the first embodiment and the second embodiment is that the shaft bearing is disposed between the external gear and the pump housing, and the fixed shaft 4 has a hollow structure. In the present embodiment, the fixed shaft 4 is provided with a flow passage for the passage of cooling oil. In this exemplary embodiment, the fixed shaft 4 is designed to be statically fixed. Driven by the external gear 2, the internal gear 3 of the pump rotates relative to the fixed shaft 4, whereby the friction is reduced, the system loss of the rotor pump is reduced, and the rotational stability of the rotor pump is effectively improved by the mutual lubrication.The mechanism by which the cooling oil cools the stator assembly in this embodiment is as follows:the motor rotor 8 and the external gear 2 commonly drive the internal gear 3 to rotate to pressurize the cooling oil flowing in through the oil inlet bore 11 so that the pressurized part of the cooling oil flows to the stator assembly through the hollow flow passage of the fixed shaft 4 to cool the stator assembly, and the heat-exchanged cooling oil flows back to the low pressure region.Moreover, the other pressurized part of the cooling oil is directly discharged from the oil discharge bore 12 through the high pressure region.Also in the present embodiment, the fixed shaft 4 is mounted with radial magnets for monitoring its position.The specific process for cooling the stator assembly in the present invention is as follows: 1) First, the apparatus is turned on, and at this time, the controller 91 is turned on, the controller 91 converts electricity into three-phase current to supply the stator winding 94 with electricity, and the electromagnetic force drives the motor rotor 8 and the external gear 2 to rotate, and by the rotation of the motor rotor 8 and the external gear 2, the cooling oil flowing in from the oil inlet hole 11 passes through the strainer 14 and then comes into the low pressure region; In addition, as shown in FIG. 2), the motor rotor 8 and the external gear 2 commonly drive the internal gear 3 to rotate about the fixed shaft 4 to pressurize the cooling oil flowing in through the oil inlet hole 11 so that the pressurized part of the cooling oil flows through the fixed shaft 4 to the stator assembly to cool the stator assembly, and the heat-exchanged cooling oil flows back to the low pressure region, using the difference between the internal gear and the external gear to generate a centrifugal force that pressurizes the cooling oil. At this time, the PTC temperature sensor detects the current temperature value of the oil and returns this temperature value to the controller 91, the controller 91 returns the current oil temperature value to the external control system; 3) The other pressurized part of the cooling oil flows through the high pressure region and is discharged directly from the oil discharge bore 12.The basic principles, features and advantages of the present invention have been shown and described above. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and that the above embodiments and descriptions merely illustrate the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes, modifications, substitutions and variations, and these changes, modifications, substitutions and variations all fall within the scope of the present invention as claimed.

Claims

An electronic oil pump comprising a pump housing (1), characterized in that the oil pump also comprises: a fixed shaft (4) arranged in the pump housing (1); an internal gear (3) eccentrically and rotatably connected to the fixed shaft (4); an external gear (2) coaxially connected to the fixed shaft (4) and rotatably connected in the pump housing (1), the external gear (2) being arranged on the outer periphery of the internal gear (3) and being capable of meshing with the internal gear (3); a motor rotor (8) fixedly connected to the outer periphery of the external gear (2); a motor stator (93) located on the outer periphery of the rotor and fixedly connected to the pump housing (1); wherein, on a plane which can pass through the axis center of the fixed shaft (4), the projected areas of the motor stator (93), the motor rotor, the external gear (2), the internal gear (3) and the fixed shaft (4) can at least partially overlap.The electronic oil pump according to claim 1, characterized in that the oil pump comprises a first shaft bearing (6), the external gear (2) being rotatably connected to one end of the fixed shaft (4) via the first shaft bearing (6), the other end of the fixed shaft (4) being connected to the pump housing (1).The electronic oil pump according to claim 1, characterized in that the oil pump comprises a second shaft bearing (6), one end of the fixed shaft (4) being rotatably connected to the pump housing (1) via the second shaft bearing (6), the other end of the fixed shaft (4) being coaxially connected to the external gear (2).The electronic oil pump according to any one of claims 1 to 3, characterized in that the oil pump further comprises an eccentric calibration component (5) located between the fixed shaft (4) and the internal gear (3), the eccentric calibration component (5) being a crescent sleeve disposed on the circumferential outer wall of the fixed shaft (4), the crescent sleeve being provided with an arc-shaped groove (51) for embedding the fixed shaft (4), the crescent sleeve being provided such that the internal gear (3) is eccentrically rotatably connected to the fixed shaft (4).The electronic oil pump according to claim 4, characterized in that the oil pump further comprises a shaft sleeve (7), the internal gear (3) being rotatably connected to the crescent sleeve and the fixed shaft (4) via the shaft sleeve (7).Electronic oil pump according to Claim 1, characterized in that the fixed shaft (4) or the external gearwheel (2) is fixedly connected to a sensor for cold start.The electronic oil pump according to any one of claims 1 to 3, characterized in that a plurality of oil passage chambers (21) are formed enclosed between the external gear (2) and the internal gear (3), wherein the volume of each oil passage chamber (21) along the rotational direction of the external gear (2) may increase stepwise first and then decrease stepwise, wherein the pump housing (1) is provided with an oil inlet bore (11) and an oil outlet bore (12), wherein the oil inlet of the oil passage chamber (21) may correspond to the oil inlet bore (11) as the oil passage chamber (21) increases stepwise, wherein the oil outlet of the oil passage chamber (21) may correspond to the oil outlet bore (12) as the oil passage chamber (21) decreases stepwise.The electronic oil pump according to claim 7, characterized in that the cooling oil can flow into the oil passage chamber (21) through the oil inlet bore (11) when the oil passage chamber (21) gradually increases, wherein the cooling oil in the oil passage chamber (21) is pushed out of the oil outlet bore (12) when the oil passage chamber (21) gradually decreases.The electronic oil pump according to claim 1, characterized in that the oil pump also comprises a circuit control module (9), the circuit control module (9) comprising a controller (91) and a stroke (92) disposed in the pump housing (1), the motor stator (93) being disposed on the stroke (92), the motor stator (93) being provided with a plurality of stator windings (94) along its circumferential direction, the motor rotor (8) being fitted on the circumferential outer circle of the external gear (2), and the circumferential outer wall of the motor rotor (8) corresponding to the circumferential inner wall of the motor stator (93).Electronic oil pump according to Claim 9, characterized in that an O-sealing ring is additionally provided on the outer periphery of the pump housing (1).

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