Electric oil pump

Abstract

An electric oil pump (100), comprising: a pump housing provided with a first inner cavity (111) and a second inner cavity (121); a rotor assembly (20) located in the first inner cavity (111), the rotor assembly (20) comprising a hollow rotor shaft (22) and a sensor magnetic ring (23), the rotor shaft (22) rotating to draw oil liquid into the first inner cavity (111), so that the sensor magnetic ring (23) is in an oil liquid environment; and a control assembly (40) located in the second inner cavity (121), the control assembly (40) comprising a sensor for detecting a magnetic field change of the sensor magnetic ring (23). The second inner cavity (121) is isolated from the first inner cavity (111), so that a sensor (42) is in an oil-free environment; an outlet end of the rotor shaft (22) is provided with a stepped outer wall; the sensor magnetic ring (23) is sleeved on the stepped outer wall in an anti-torsion manner, and an end surface of the sensor magnetic ring (23) is flush with an end surface of an outlet end of the rotor shaft (22). When the sensor magnetic ring (23) is installed on the rotor shaft (22), a connecting member is omitted, thereby facilitating installation, lowering costs, and reducing the loss rate of the sensor magnetic ring (23). The sensor magnetic ring (23) is flush with the end surface of the rotor shaft (22), so that the axial distance between the sensor magnetic ring (23) and the sensor in the oil liquid environment is reduced, thereby improving the sensor detection precision.

Description

Electronic oil pump Technical Field

[0001] The present disclosure relates to the technical field of lubrication and cooling of electric-driven vehicles, and in particular to an electronic oil pump. Background Art

[0002] The electric vehicle industry is developing rapidly. As the performance of electric vehicles develops towards safer, more reliable, more stable, fully automatic, intelligent, environmentally friendly and energy-saving directions, electronic oil pumps are widely used in the lubrication and cooling systems of electric vehicles. Compared with mechanical oil pumps, electronic oil pumps have their own control units, which can supply flow and oil pressure on demand, reduce energy waste, and can well meet market requirements.

[0003] The motor inside the electronic oil pump provides power for oil circulation, thereby lubricating and cooling various related components in the engine outside the electronic oil pump.

[0004] To ensure stable operation of the electronic oil pump, a comprehensive lubrication solution is also required inside the electronic oil pump to prevent the electronic oil pump from overheating and affecting its own performance and efficiency. To this end, related technologies have designed the rotor shaft of the electronic oil pump to have a hollow structure, allowing some oil to enter the cavity inside the electronic oil pump through the hollow rotor shaft. This allows some components of the electronic oil pump cavity (such as the rotor assembly and the sensor magnetic ring) to be immersed in oil, and the internal circulation of some oil within the electronic oil pump to achieve self-cooling of the electronic oil pump.

[0005] In the motor section of an electronic oil pump, the sensor magnet is typically secured to the rotor shaft using adhesive or additional fasteners. However, when the electronic oil pump is immersed in oil, the oil can cause the adhesive to foam, loosening the sensor magnet or even causing it to fall off.

[0006] Sensor magnets secured with additional connectors require additional axial or radial space, and the additional connectors increase material costs. Furthermore, the sensor magnets are often press-fitted into the connectors. To protect the sensor magnets from press-fitting effects during installation, extra care must be taken during assembly, resulting in high installation costs.

[0007] Summary of the Invention

[0008] In order to overcome the problems existing in the related art, the present disclosure provides an electronic oil pump.

[0009] According to a first aspect of an embodiment of the present disclosure, the present disclosure provides an electronic oil pump, comprising: a pump housing, comprising a first inner cavity and a second inner cavity; a rotor assembly, located in the first inner cavity, the rotor assembly comprising a hollow rotor shaft and a sensor magnetic ring, the rotor shaft rotates to suck oil into the first inner cavity, so that the sensor magnetic ring is in an oil environment; a control assembly, located in the second inner cavity, the control assembly comprising a sensor for detecting changes in the magnetic field of the sensor magnetic ring, the second inner cavity is isolated from the first inner cavity, so that the sensor is in an oil-free environment, wherein the outlet end of the rotor shaft is provided with a stepped outer wall, the sensor magnetic ring is torsionally sleeved on the stepped outer wall, and the end face of the sensor magnetic ring is flush with the end face of the outlet end of the rotor shaft.

[0010] In some embodiments, the stepped outer wall of the rotor shaft includes one or more flat surfaces for preventing the sensor magnetic ring from rotating relative to the rotor shaft.

[0011] In some embodiments, the control assembly further includes a control circuit board, the sensor is fixed to an end surface of the control circuit board close to the rotor shaft, and the sensor is axially arranged opposite to the sensor magnetic ring.

[0012] In some embodiments, the pump casing includes: a first pump casing, including the first inner cavity; a second pump casing, including the second inner cavity, and the second pump casing includes a radial isolation wall to isolate the first inner cavity and the second inner cavity, wherein an isolation member is provided in the middle of the isolation wall, and the isolation member is axially located between the sensor and the sensor magnetic ring, and the thickness of the isolation member is less than the thickness of the isolation wall.

[0013] In some embodiments, a radial second partition wall is provided in the first pump housing, and the second partition wall axially divides the first pump housing into the first inner cavity and the third inner cavity, and the inlet end of the rotor shaft is located in the third inner cavity.

[0014] In some embodiments, the electronic oil pump also includes an oil pump assembly, which is located in the third inner cavity. The oil pump assembly is sleeved on the outside of the rotor shaft and is used to pump oil into the inlet end of the rotor shaft and flow into the first inner cavity from the outlet end of the rotor shaft.

[0015] In some embodiments, the oil pump assembly includes: an internal gear, sleeved on the outer wall of the rotor shaft in a torsionally fixed manner; and an external gear, sleeved on the outside of the internal gear and radially spaced from the internal gear to form a hydraulic chamber.

[0016] In some embodiments, the pump housing further includes a pump cover, which is disposed at one end of the third inner cavity of the first pump housing. The pump cover is provided with an oil inlet hole, and the first pump housing is provided with an oil outlet hole.

[0017] In some embodiments, the stator assembly is sleeved on the outside of the rotor assembly, and the stator assembly includes a stator core and a stator winding.

[0018] In some embodiments, the sensor is a Hall sensor.

[0019] The technical solution provided by the embodiments of the present disclosure may include the following beneficial effects: the sensor magnetic ring in the oil environment is connected to the end of the outlet end of the rotor shaft through a torsion-resistant connection, without the need for glue and omitting the connector, which not only reduces the cost, but also simplifies the way of assembling the sensor magnetic ring on the rotor shaft, reducing the loss rate of the sensor magnetic ring. In addition, the sensor magnetic ring is sleeved on the stepped outer wall of the rotor shaft, allowing the hollow rotor shaft to pump oil into the first inner cavity to achieve the effect of cooling the stator assembly. In addition, the stepped outer wall of the rotor shaft can axially position the position of the sensor magnetic ring, and the end face of the sensor magnetic ring is flush with the end face of the outlet end of the rotor shaft, so that the sensor magnetic ring in the oil environment is closer to the sensor in the second inner cavity, thereby improving the accuracy of the sensor in detecting the rotor position. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0021] FIG1 is a schematic cross-sectional view of an electronic oil pump according to an exemplary embodiment;

[0022] FIG2 is an exploded view of a rotor shaft and a sensor magnetic ring according to an exemplary embodiment;

[0023] FIG3 is an assembly diagram of a rotor shaft and a sensor magnetic ring according to an exemplary embodiment. DETAILED DESCRIPTION

[0024] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all possible embodiments consistent with the present disclosure. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present disclosure, as detailed in the appended claims.

[0025] In the present invention, unless otherwise specified, axial direction A, radial direction R and circumferential direction W refer to the axial direction A, radial direction R and circumferential direction W of the electronic oil pump respectively; the term "torsion-resistant connection" means that torque can be transmitted between two components, and the methods for achieving torque-resistant connection may include interference fit and bolt connection, etc.

[0026] To solve the above technical problems, the present disclosure provides an electronic oil pump 100. As shown in FIG1 , the electronic oil pump 100 includes a pump housing and a rotor assembly 20, a stator assembly 30, a control assembly 40 and an oil pump assembly 50 located inside the pump housing.

[0027] In this embodiment, the pump housing may include a first pump housing 11, a second pump housing 12, and a pump cover 13. As shown in FIG1 , the second pump housing 12 and the pump cover 13 are located at the axial ends of the first pump housing 11, respectively. The first pump housing 11 and the second pump housing 12, as well as the first pump housing 11 and the pump cover 13, may be fixedly connected by any means, such as plug-in or sleeve connection, and the connection between the first pump housing 11 and the second pump housing 12 must be sealed.

[0028] The pump housing is divided into a first inner cavity 111, a second inner cavity 121, and a third inner cavity 112. As shown in FIG1 , a partition wall 122 is provided below the second pump housing 12. The first inner cavity 111 is located below the partition wall 122 and within the first pump housing 11, while the second inner cavity 121 is located above the partition wall 122 and within the second pump housing 12. The partition wall 122 isolates the first inner cavity 111 from the second inner cavity 121, preventing oil from flowing or exchanging.

[0029] In this embodiment, the control assembly 40 is located within the second inner chamber 121, making the second inner chamber 121 a dry chamber with no oil. The rotor assembly 20 and stator assembly 30 are both located within the first inner chamber 111, with the stator assembly 30 nested outside the rotor assembly 20. Therefore, the first inner chamber 111 contains oil, making it a wet chamber with an oil environment. The stator assembly 30 in the first inner chamber 111 is electrically connected to the control assembly 40 in the second inner chamber 121 via wires or the like.

[0030] The stator assembly 30 includes a stator core 31 and stator windings 32. When the electronic oil pump 100 is operating, the stator windings 32 of the stator assembly 30 are energized, and the control assembly 40 controls the current flowing through the stator windings 32 of the stator assembly 30 to vary according to a predetermined pattern, thereby controlling the stator assembly 30 to generate a varying excitation magnetic field. The rotor assembly 20 rotates under the influence of the excitation magnetic field.

[0031] The rotor assembly 20 includes a rotor 21, a rotor shaft 22, and a sensor magnet ring 23. The rotor 21 is mounted on the outer wall of the rotor shaft 22 in a torsionally rigid manner. The rotor 21 rotates under the action of the excitation magnetic field, driving the rotor shaft 22 to rotate. A bearing is provided between the rotor shaft 22 and the first pump housing 11 to enable the rotor shaft 22 to rotate relative to the first pump housing 11.

[0032] Furthermore, the rotor shaft 22 is a hollow rotor shaft 22, and the rotor shaft 22 is provided with an axially through oil hole 221. The oil hole 221 forms an inlet end 222 and an outlet end 223 of the rotor shaft 22 in the axial direction. The oil can enter the oil hole 221 through the inlet end 222 of the rotor shaft 22 and flow into the first inner cavity 111 from the outlet end 223 of the oil hole 221, so that the stator assembly 30, the rotor 21 of the rotor assembly 20 and the sensor magnetic ring 23 are in an oil environment. The first pump housing 11 is provided with an oil outlet hole, so that the oil can realize cooling circulation in the first inner cavity 111, thereby cooling the stator assembly 30 located in the first inner cavity 111 and lubricating components such as bearings, thereby realizing self-cooling and lubrication of the electronic oil pump 100.

[0033] Compared with the solid rotor shaft 22 in the electronic oil pump 100 in the related art, part of the low-pressure oil flows into the interior of the electronic oil pump 100 through some preset side holes, resulting in a more complicated oil circulation path and poor cooling effect of the electronic oil pump 100. The oil hole 221 of the rotor shaft 22 disclosed in the present invention reduces the path length and time of the oil flow, increases the circulation speed of the oil inside the electronic oil pump 100, and ensures the self-cooling effect of the electronic oil pump 100.

[0034] The sensor magnetic ring 23 is located at the outlet end 223 of the rotor shaft 22. Specifically, as shown in Figure 2, the outer wall at the outlet end 223 of the rotor shaft 22 is provided with a stepped outer wall 224, and the inner wall of the sensor magnetic ring 23 is torsionally connected to the stepped outer wall 224 of the rotor shaft 22. It can be seen that the sensor magnetic ring 23 in an oil environment is torsionally connected to the end of the outlet end 223 of the rotor shaft 22 without the need for glue fixation, thereby avoiding the falling off of the sensor magnetic ring 23 due to the falling off of the glue in the oil environment, and omitting the connecting parts, further reducing the cost. In addition, the way of assembling the sensor on the rotor shaft 22 is simple, which reduces the loss rate of the sensor magnetic ring 23 during installation.

[0035] The control component 40 also includes a control circuit board 41 and a sensor 42. In this embodiment, the sensor 42 can be a Hall sensor 42. The sensor 42 is fixed on a side of the control circuit board 41 close to the rotor shaft 22, and the sensor 42 is arranged axially opposite to the sensor magnetic ring 23. The Hall sensor 42 is used to detect the magnetic field changes of the sensor magnetic ring 23. The sensor 42 and the sensor magnetic ring 23 are arranged opposite each other, so that the sensor 42 can fully receive the magnetic field changes of the sensor magnetic ring 23. The ECU determines the position of the rotor 21 based on the signal of the magnetic field change, thereby controlling the power-on time of the stator winding 32 of the stator assembly 30, thereby improving the efficiency of the stator assembly 30 of the electronic oil pump 100 in driving the rotor assembly 20 to rotate.

[0036] Furthermore, the axial length of the stepped outer wall 224 is the same as the axial thickness of the sensor magnetic ring 23, so that the end surface of the sensor magnetic ring 23 is flush with the end surface of the outlet end 223 of the rotor shaft 22. The stepped outer wall 224 of the rotor shaft 22 can axially position the sensor magnetic ring 23, so that the end surface of the sensor magnetic ring 23 is flush with the end surface of the outlet end 223 of the rotor shaft 22. While reducing the axial dimension, it also allows the sensor magnetic ring 23 in the oil environment to be closer to the sensor 42 in the second inner cavity 121, allowing the sensor 42 to better monitor changes in the magnetic field and improve the accuracy of the sensor 42 in detecting the position of the rotor 21.

[0037] In some embodiments, as shown in FIG1 , a spacer 123 is disposed in the middle of the isolation wall 122. The spacer 123 is positioned between the sensor 42 and the sensor magnetic ring 23 along the axial direction A. The thickness of the spacer 123 is less than that of the isolation wall 122. Using the thinner spacer 123 instead of the thicker isolation wall 122 reduces the space occupied by the isolation wall 122 in the axial direction, shortens the axial distance between the sensor magnetic ring 23 in the first inner cavity 111 and the sensor 42 in the second inner cavity 121, and improves the detection accuracy of the sensor 42.

[0038] Furthermore, the stepped outer wall 224 of the rotor shaft 22 includes one or more flat surfaces 225 to prevent the sensor magnetic ring 23 from rotating relative to the rotor shaft 22. In this embodiment, as shown in Figures 2 and 3, the stepped outer wall 224 of the rotor shaft 22 has two flat surfaces 225. The two flat surfaces 225 are symmetrically arranged, so that the inner hole of the sensor magnetic ring 23 can have a waist-shaped hole structure. This not only achieves a torsion-resistant connection between the sensor magnetic ring 23 and the rotor shaft 22, but also prevents relative rotation between the two.

[0039] In some other embodiments, the stepped outer wall 224 may also be in other shapes, such as a quadrilateral, a pentagon, etc., which is not specifically limited here.

[0040] Furthermore, a radial second isolation wall 113 can be provided in the first pump housing 11, and the second isolation wall 113 divides the first pump housing 11 into a first inner cavity 111 and a third inner cavity 112 along the axial direction. The third inner cavity 112 and the first inner cavity 111 can be connected by oil so that the first inner cavity 111 and the third inner cavity 112 are in an oil environment.

[0041] Specifically, as shown in Figure 1, the pump cover 13 is located below the first pump housing 11 shown in Figure 1. The pump cover 13 is provided with an oil inlet hole (not shown in the figure), and an oil inlet chamber 131 is formed inside the pump cover 13. After the oil enters the pump cover 13 through the oil inlet hole, it is temporarily stored in the oil inlet chamber 131, and the inlet end 222 of the rotor shaft 22 extends into the third inner chamber 112, so that the oil inlet chamber 131 of the pump cover 13 is connected with the inlet end 222 of the rotor shaft 22.

[0042] In some embodiments, the electronic oil pump 100 also includes an oil pump assembly 50, which is located in the third inner cavity 112. The oil pump assembly 50 is sleeved on the outside of the rotor shaft 22 and is used to pump oil into the inlet end 222 of the rotor shaft 22 and flow into the first inner cavity 111 from the outlet end 223 of the rotor shaft 22.

[0043] Specifically, the oil pump assembly 50 includes an internal gear 51 and an external gear 52. The internal gear 51 is torsionally sleeved on the outer wall of the rotor shaft 22; the external gear 52 is sleeved on the outer periphery of the internal gear 51, and the external gear 52 and the internal gear 51 are radially spaced to form a hydraulic chamber 53, and the hydraulic chamber 53 is connected to the oil inlet chamber 131 of the pump cover 13.

[0044] The rotor shaft 22 directly drives the internal gear 51 of the oil pump assembly 50 to rotate. As the internal gear 51 rotates, due to the eccentricity between the external gear 52 and the internal gear 51, a portion of the internal teeth of the internal gear 51 meshes with a portion of the internal teeth of the external gear 52, thereby driving the external gear 52 to rotate. During each rotation of the external gear 52 and the internal gear 51, the volume of the hydraulic chamber 53 changes. When the internal gear 51 rotates from its starting position to a certain angle, the volume of the hydraulic chamber 53 gradually increases, creating a partial vacuum. Oil is then drawn into the hydraulic chamber 53 from the oil inlet chamber 131. As the internal gear 51 and the external gear 52 continue to rotate, the volume of the hydraulic chamber 53, which was originally filled with oil, gradually decreases. This squeezes the oil, forcing it out of the hydraulic chamber 53, generating flow momentum. The oil is then pumped into the oil hole 221 of the rotor shaft 22 and ultimately into the first inner chamber 111 for cooling before being discharged through the oil outlet of the first pump housing 11.

[0045] It will be further understood that the terms "first," "second," and the like are used to describe various structures, but these structures should not be limited to these terms. These terms are merely used to distinguish structures of the same type from one another and do not indicate a particular order or degree of importance. In fact, the expressions "first," "second," and the like are fully interchangeable. For example, a first structure could also be referred to as a second structure, and similarly, a second structure could also be referred to as a first structure without departing from the scope of this disclosure.

[0046] It can be further understood that the terms "center", "longitudinal", "lateral", "front", "back", "up", "down", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this embodiment and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation.

[0047] Those skilled in the art will readily appreciate other embodiments of the present disclosure after considering the specification and practicing the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered merely as exemplary, and the true scope and spirit of the present disclosure are indicated by the following claims.

[0048] It should be understood that the present disclosure is not limited to the exact structures described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the scope of the appended claims.

Claims

1. An electronic oil pump (100), characterized in that: include: A pump housing comprising a first inner cavity (111) and a second inner cavity (121); A rotor assembly (20) is located in the first inner cavity (111), the rotor assembly (20) comprising a hollow rotor shaft (22) and a sensor magnetic ring (23), the rotor shaft (22) rotates to draw oil into the first inner cavity (111), so that the sensor magnetic ring (23) is in an oil environment; A control component (40) is located in the second inner cavity (121), and the control component (40) includes a sensor (42) for detecting changes in the magnetic field of the sensor magnetic ring (23). The second inner cavity (121) is isolated from the first inner cavity (111), so that the sensor (42) is in an oil-free environment. The outlet end (223) of the rotor shaft (22) is provided with a stepped outer wall (224), the sensor magnetic ring (23) is sleeved on the stepped outer wall (224) in a torsionally anti-rotating manner, and the end face of the sensor magnetic ring (23) is flush with the end face of the outlet end (223) of the rotor shaft (22).

2. The electronic oil pump (100) according to claim 1, characterized in that The stepped outer wall (224) of the rotor shaft (22) includes one or more flat surfaces (225) for preventing the sensor magnetic ring (23) from rotating relative to the rotor shaft (22).

3. The electronic oil pump (100) according to claim 1, characterized in that The control assembly (40) further includes a control electric board (41), the sensor (42) being fixed on the end face of the control electric board (41) close to the rotor shaft (22), and the sensor (42) being arranged axially opposite to the sensor magnetic ring (23).

4. The electronic oil pump (100) according to claim 1, characterized in that The pump housing comprises: A first pump housing (11) comprising the first inner cavity (111); The second pump housing (12) includes the second inner cavity (121), and the second pump housing (12) includes a radial partition wall (122) to isolate the first inner cavity (111) from the second inner cavity (121). Wherein, an isolation member (123) is provided in the middle of the isolation wall (122). (123) is located between the sensor (42) and the sensor magnetic ring (23) along the axial direction, and the thickness of the isolation member (123) is smaller than the thickness of the isolation wall (122).

5. The electronic oil pump (100) according to claim 4, characterized in that: A radial second partition wall (122) is provided in the first pump housing (11), and the second partition wall (122) divides the first pump housing (11) into the first inner cavity (111) and a third inner cavity (112) along the axial direction. The inlet end (222) of the rotor shaft (22) is located in the third inner cavity (112).

6. The electronic oil pump (100) according to claim 5, characterized in that: The electronic oil pump (100) further comprises an oil pump assembly (50), wherein the oil pump assembly (50) is located in the third inner cavity (112), and the oil pump assembly (50) is sleeved on the outside of the rotor shaft (22) and is used for pumping oil into the inlet end (222) of the rotor shaft (22), and flowing the oil into the first inner cavity (111) from the outlet end (223) of the rotor shaft (22).

7. The electronic oil pump (100) according to claim 6, characterized in that: The oil pump assembly (50) comprises: An internal gear (51) is sleeved on the outer wall of the rotor shaft (22) in a rotationally fixed manner; The external gear (52) is sleeved on the outside of the internal gear (51) and radially spaced apart from the internal gear (51) to form a hydraulic chamber (53).

8. The electronic oil pump (100) according to claim 5, characterized in that The electronic oil pump (100) further comprises a pump cover (13), wherein the pump cover (13) is arranged at one end of the third inner cavity (112) of the first pump housing (11), the pump cover (13) is provided with an oil inlet hole, and the first pump housing (11) is provided with an oil outlet hole.

9. The electronic oil pump (100) according to claim 1, characterized in that: The stator assembly (30) is sleeved on the outside of the rotor assembly (20), and the stator assembly (30) includes a stator core (31) and a stator winding (32).

10. The electronic oil pump (100) according to claim 1, characterized in that The sensor (42) is a Hall sensor.

Images