WO2025199860A1 - Electric oil pump - Google Patents

Abstract

An electric oil pump, which comprises a drive electric motor (10), a pump rotor assembly (20) and a housing (30), wherein the housing (30) comprises an electric motor cavity (Cm) for accommodating the drive electric motor (10); and the drive electric motor (10) comprises an electric motor shaft (13), which is in transmission connection with the pump rotor assembly (20) so as to drive same, and comprises an oil guiding hole (14) which axially runs through same and is in communication with the electric motor cavity (Cm). The electric oil pump further comprises a propeller fan member (40), which is fixedly mounted in the oil guiding hole (14) in such a way that the propeller fan member (40) can generate a pump suction force towards the electric motor cavity (Cm) as the electric motor shaft (13) rotates relative to the housing (30).

Description

Electric oil pump Technical Field

The present invention relates to the technical field of oil pumps, and in particular to an electric oil pump.

Background Art

An oil pump is a device used to drive fluid flow and generate fluid pressure in mechanical systems. For example, in modern motor vehicles, oil pumps are commonly used to move the working fluid for cooling and lubrication. These oil pumps are typically driven by a drive motor, hence the name electric oil pump.

An electric oil pump typically consists of a drive motor, a pump rotor assembly, and a housing. The drive motor rotates the pump rotor assembly, generating pump suction. The drive motor and the pump rotor assembly are housed in separate chambers within the housing. The motor chamber housing the drive motor typically requires oil for cooling and lubrication.

For example, CN 216741978 U discloses an electric oil pump, which connects the motor cavity of the electric oil pump with the high-pressure cavity and the low-pressure cavity of the pump rotor assembly respectively, so that the engine oil first enters the motor cavity from the high-pressure cavity under the action of oil pressure, circulates in the motor cavity, and then returns to the low-pressure cavity, thereby realizing cooling of the drive motor.

However, in this solution, a portion of the oil in the high-pressure chamber of the pump rotor assembly circulates back to the low-pressure chamber through the motor chamber, which has an effect similar to leakage inside the oil pump, resulting in a decrease in the pumping efficiency of the oil pump and thus reducing the overall performance of the oil pump.

Summary of the Invention

Therefore, the technical problem to be solved by the present invention is to provide an improved electric oil pump.

The above technical problems are solved by an electric oil pump according to the present invention. The electric oil pump includes a drive motor, a pump rotor assembly and a housing. The housing includes a motor cavity for accommodating the drive motor. The drive motor includes a motor shaft that is transmission-connected to the pump rotor assembly to drive the pump rotor assembly. The motor shaft includes an oil inlet hole that axially passes through and is connected to the motor cavity. The electric oil pump also includes a propeller fan structure. The propeller-fan component is fixedly mounted in the oil inlet hole, enabling the propeller-fan component to generate a pumping force into the motor cavity as the motor shaft rotates relative to the housing. The propeller-fan component mounted in the oil inlet hole can function similarly to a fan or propeller, generating a pumping force as the motor shaft rotates, thereby pumping oil into the motor cavity and improving the efficiency of oil supply within the motor cavity. Furthermore, since the pumping force of the propeller-fan component is directly generated by the rotation of the motor shaft, it does not consume power from the pump rotor assembly, thereby improving the efficiency of the electric oil pump.

According to a preferred embodiment of the present invention, the pump rotor assembly may include a low-pressure chamber for drawing in oil and a high-pressure chamber for pumping out the drawn-in oil. The electric oil pump may include an oil supply chamber connected to the low-pressure chamber to supply oil to the pump rotor assembly. An oil inlet may be connected to the oil supply chamber to pump oil from the oil supply chamber to the motor chamber. Because the propeller assembly can directly generate pumping suction, the oil inlet can draw oil directly from the oil supply chamber, eliminating the need to connect to the high-pressure chamber of the pump rotor assembly to pump oil into the motor chamber using oil pressure. This reduces the pump rotor assembly's pumping power consumption, thereby improving pumping efficiency.

According to another preferred embodiment of the present invention, the motor cavity can communicate with the low-pressure cavity, allowing the oil in the motor cavity to flow into the low-pressure cavity. This allows the oil introduced into the motor cavity via the oil inlet hole to circulate back to the low-pressure cavity of the pump rotor assembly under the action of the oil pressure, thereby increasing the oil intake of the low-pressure cavity and further improving the pumping efficiency of the pump rotor assembly.

According to another preferred embodiment of the present invention, the motor shaft may include a first end and a second end that are axially opposed to each other. The first end is drivingly connected to the pump rotor assembly, and the second end extends into the motor cavity. The propeller member may be mounted radially inwardly of the first end. This places the propeller member closer to the source of the oil, thereby improving the efficiency of oil suction.

According to another preferred embodiment of the present invention, the propeller fan component may not extend beyond the first end in the axial direction. This prevents the propeller fan component from contacting other components outside the motor shaft, especially the housing, thereby avoiding interference.

According to another preferred embodiment of the present invention, the oil inlet hole may include a first section and a second section divided axially. The first section extends axially between the axial end surface of the first end and the second section. The inner diameter of the first section is larger than the inner diameter of the second section, so that a stepped surface facing the first end is formed at the intersection of the first section and the second section. The propeller member can be installed in the first section and abut the stepped surface. The stepped surface can thus define the axial position of the propeller member in the oil inlet hole.

According to another preferred embodiment of the present invention, a propeller-fan member may include a connecting portion and a plurality of blades respectively connected to the connecting portion. The plurality of blades are circumferentially spaced and distributed around the rotation axis of the motor shaft and are circumferentially inclined in the same direction, so that the propeller-fan member generates a pumping force into the motor cavity when the motor shaft rotates in a predetermined rotation direction. The blades can be used to generate the pumping force, and the connecting portion can connect the blades into a single body.

According to another preferred embodiment of the present invention, the propeller fan component can have one of the following structures: the connecting portion is a connecting ring extending around the rotation axis of the motor shaft and fixed to the inner wall of the oil inlet hole, and the multiple blades extend radially inward from the connecting portion; the connecting portion is a connecting column extending axially along the rotation axis of the motor shaft, and the multiple blades extend radially outward from the connecting portion and are fixed to the inner wall of the oil inlet hole; or the connecting portion extends parallel to the rotation axis of the motor shaft, and the multiple blades are respectively connected to the same axial end of the connecting portion. The propeller fan component can be presented in various different forms, as long as it can generate pump suction.

According to another preferred embodiment of the present invention, the connecting portion may be a connecting piece extending parallel to the rotational axis of the motor shaft, and the propeller fan component may include two blades, each of which is a sheet-like structure extending from the same axial end of the connecting portion and inclined in opposite directions relative to the plane extending from the connecting portion. This allows the propeller fan component to be directly stamped from sheet material, thereby reducing production costs.

According to another preferred embodiment of the present invention, two fan blades can be connected to the axial end portion of the connecting portion facing the first end. This makes the fan blades closer to the source of the oil, thereby improving the suction effect.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is further described below with reference to the accompanying drawings. Elements with the same function are represented by the same reference numerals in the drawings.

FIG1 is a cross-sectional view showing an electric oil pump according to an exemplary embodiment of the present invention;

FIG2 shows an end elevation view of an electric oil pump according to an exemplary embodiment of the present invention;

3 is a cross-sectional view showing a motor shaft to which an electric oil pump according to an exemplary embodiment of the present invention is applied;

FIG4 is a perspective view showing a propeller fan member to which an electric oil pump according to an exemplary embodiment of the present invention is applied; and

FIG. 5 shows a detailed view of a first end of a motor shaft to which an electric oil pump according to an exemplary embodiment of the present invention is applied.

DETAILED DESCRIPTION

The following detailed description and accompanying drawings are used to illustrate the principles of the present invention. The present invention is not limited to the preferred embodiments described. The scope of protection of the present invention is defined by the claims.

According to an embodiment of the present invention, an electric oil pump for driving a working fluid and generating fluid pressure is provided. Figures 1 to 5 illustrate an exemplary embodiment of the electric oil pump according to the present invention. The specific structure of the electric oil pump will be described below with reference to the accompanying drawings.

Figure 1 shows a perspective cross-sectional view of an electric oil pump according to an exemplary embodiment. As shown in Figure 1 , the electric oil pump mainly includes a drive motor 10, a pump rotor assembly 20, and a housing 30. The drive motor 10 and the pump rotor assembly 20 are installed in the housing 30.

The drive motor 10 includes a stator 11, a rotor 12, and a motor shaft 13. The stator 11 is fixed within a housing 30. The rotor 12 is coaxially mounted radially inwardly of the stator 11 and is rotatable relative to the stator 11 about a central axis parallel to the axial direction. The motor shaft 13 is coaxially connected to the rotor 12 in a torque-proof manner, specifically fixed radially inwardly of the rotor 12, thereby being rotatable relative to the stator 11 and the housing 30 along the common central axis. The motor shaft 13 includes two axially opposing ends, namely a first end 13a and a second end 13b. These ends of the motor shaft 13 each protrude axially beyond the rotor 12.

The stator 11 and rotor 12 of the drive motor 10 are axially spaced from the pump rotor assembly 20 and are housed in two different chambers of the housing 30. The chamber housing the drive motor 10 (particularly the stator 11 and rotor 12) can be referred to as the motor chamber Cm, while the chamber housing the pump rotor assembly 20 can be referred to as the pump rotor chamber. The motor chamber Cm and the pump rotor chamber are axially separated by a partition wall 31a in the housing 30. The motor shaft 13 axially passes through the rotor 12 and the pump rotor assembly 20, respectively. The first end 13a of the motor shaft 13 extends axially away from the rotor 12 and is in driving connection with the pump rotor assembly 20, while the second end 13b extends axially out of the rotor 12, away from the pump rotor assembly 20, and into the motor chamber Cm. In other words, the second end 13b is axially located on the side of the rotor 12 away from the pump rotor assembly 20.

The motor shaft 13 is used to transmit the driving torque generated by the drive motor 10 to the pump rotor assembly 20. The pump rotor assembly 20 can be driven by the motor shaft 13 to generate pump suction. The pump rotor assembly 20 can be any pump device known in the art, such as a gear pump. Its specific structure and operating principle for generating pump suction are widely known and will not be described in detail here.

As shown in Figures 1 and 3, the motor shaft 13 includes an oil introduction hole 14 extending substantially axially. Oil introduction hole 14 extends from the axial end surface of the first end 13a of the motor shaft 13 to the axial end surface of the second end 13b, axially penetrating the motor shaft 13 and communicating with the motor chamber Cm via an opening at the second end 13b. The opening of the oil introduction hole 14 at the first end 13a communicates with a chamber containing engine oil.

The electric oil pump also includes a propeller assembly 40. The propeller assembly 40 is fixedly mounted in the oil inlet hole 14, enabling it to generate a pumping force into the motor cavity Cm as the motor shaft 13 rotates relative to the housing 30. This propeller assembly 40 is similar to a common fan or propeller. When rotating in a predetermined direction, the propeller assembly 40 can generate a fluid pressure differential on both sides of the axial direction through its tilted blades, thereby promoting fluid flow from one axial side to the other. The specific principles of this propeller assembly 40 are widely known and will not be elaborated here.

Specifically, the propeller fan component 40 may include a connecting portion 41 and a plurality of blades 42, which are respectively connected to the connecting portion 41 to form a whole. These blades 42 may be formed integrally with the connecting portion 41, or may be fixed together after being formed separately. These blades 42 are spaced circumferentially around the rotation axis of the motor shaft 13, preferably evenly spaced, and each blade 42 is tilted in the same direction in the circumferential direction, so that the propeller fan component 40 generates a pumping suction force toward the motor cavity Cm when the motor shaft 13 rotates in a predetermined rotation direction. The inclination of the blades 42 means that the blades 42 have a non-zero inclination angle toward one side of the circumference relative to the plane passing through the rotation axis of the motor shaft 13.

The propeller member 40 can have various structures. For example, in one embodiment, the connecting portion 41 can be a connecting ring extending around the rotation axis of the motor shaft 13 and fixed to the inner wall of the oil guide hole 14 (e.g., by interference fit or bonding), and the blades 42 can each extend radially inward from the connecting portion 41.

For example, in another embodiment, the connecting portion 41 can be a connecting column (e.g., a circular column) extending axially along the rotation axis of the motor shaft 13, and the fan blades 42 can respectively extend radially outward from the connecting portion 41 and be fixed to the inner wall of the oil inlet hole 14 (e.g., by interference fit or bonding).

For another example, in yet another embodiment, the connecting portion 41 may extend parallel to the rotation axis of the motor shaft 13, and the blades 42 are respectively connected to the same axial end of the connecting portion 41. The blades 42 shown in Figures 1 to 5 are a specific implementation of this embodiment. As shown in Figures 4 and 5, the connecting portion 41 is preferably a connecting sheet (a planar sheet structure) extending parallel to the rotation axis of the motor shaft 13 (especially extending through the rotation axis), which may have a roughly rectangular shape. The propeller fan component 40 may include two blades 42, both of which are roughly planar sheet structures and extend from the same axial end of the connecting portion 41 and are inclined in opposite directions relative to the extension plane of the connecting portion 41. At the same time, the two blades 42 are located on both sides of the midpoint of the end edge of the connecting portion 41 and have approximately the same size and shape. This makes the two blades 42 inclined in the same direction in the circumferential direction. The connecting portion 41 and the two blades 42 can respectively abut the inner wall of the oil inlet hole 14 and can be fixed to the oil inlet hole 14 by an interference fit. Such two blades 42 can be formed integrally with the connecting portion 41, and in particular can be formed by stamping a single sheet of material. Therefore, such a propeller fan component 40 can have a low processing cost.

5 , the two blades 42 of the propeller member 40 can be connected to the axial end portion of the connecting portion 41 facing the first end 13a. This allows the blades 42 to be closer to the oil source to improve the pumping effect.

As shown in Figures 1 and 2, the pump rotor assembly 20 includes a low-pressure chamber Cl for sucking in oil and a high-pressure chamber Ch for pumping out the sucked-in oil. The electric oil pump includes an oil supply chamber Cs that is connected to the low-pressure chamber Cl to supply oil to the pump rotor assembly 20. In the electric oil pump according to the present invention, since the propeller member 40 can generate a pumping suction force, the oil can be pumped into the motor chamber Cm without relying on the oil pressure in the chamber. Therefore, the opening of the oil inlet hole 14 located on the first end 13a can not be connected to the high-pressure chamber Ch. Particularly preferably, the oil inlet hole 14 can be connected to the oil supply chamber Cs via its opening located on the first end 13a so as to pump oil from the oil supply chamber Cs to the motor chamber Cm.

Specifically, as shown in Figures 1 and 2, the housing 30 may include a main body 31 and a pump head cover 32. The main body 31 is generally cylindrical around the central axis. The motor cavity Cm and the pump rotor cavity are basically formed in the main body 31. As shown in Figure 1, the motor cavity Cm and the pump rotor cavity are axially separated by a partition wall 31a formed inside the main body 31. The pump rotor cavity is open axially away from the rotor 12, and the pump head cover 32 is fixed to the main body 31 at the open end of the pump rotor cavity to close the pump rotor cavity. The low-pressure chamber Cl and the high-pressure chamber Ch are respectively formed between the pump head cover 32 and the pump rotor assembly. The oil supply chamber Cs is in It is axially located on the side of the pump head cover 32 facing away from the pump rotor assembly 20 and is connected to the low-pressure chamber Cl. The low-pressure chamber Cl and the high-pressure chamber Ch can be converted into each other by the rotation of the pump rotor assembly 20, but their positions relative to the housing 30 are fixed. An oil inlet hole 32a aligned with the motor shaft 13, especially with the oil inlet hole 14, can be formed on the pump head cover 32. The oil inlet hole 32a axially penetrates the pump head cover 32, so that the oil in the oil supply chamber Cs can flow directly into the oil inlet hole 14 through the oil inlet hole 32a. As a result, a part of the oil from the oil supply chamber Cs enters the low-pressure chamber Cl under the action of the pressure difference of the low-pressure chamber C1, and the other part enters the motor chamber Cm through the oil inlet hole 14 under the action of the pump suction force of the fan component 40.

Further preferably, the motor chamber Cm can also communicate with the low-pressure chamber C1, allowing the oil drawn into the oil inlet hole 14 to circulate within the motor chamber Cm and then flow into the low-pressure chamber C1 under the action of a pressure differential. For example, an oil outlet hole 31b aligned with the low-pressure chamber C1 can be formed in the partition wall 31a. This allows the oil in the motor chamber Cm to be further pumped out of the pump rotor assembly 20 via the high-pressure chamber Ch.

To position the propeller member 40 close to the source of engine oil, as shown in Figure 1 , the propeller member 40 can be preferably mounted radially inward of the first end 13a. To prevent the rotating propeller member 40 from interfering with external fixed components, the propeller member 40 can preferably not extend axially beyond the first end 13a. In particular, a certain axial clearance can exist between the end of the propeller member 40 facing the pump head cover 32 and the axial end surface of the first end 13a.

As shown in Figures 3 and 5, in a preferred embodiment, the propeller component 40 can also be positioned by a step surface in the oil introduction hole 14. Specifically, the oil introduction hole 14 may include a first section 14a and a second section 14b divided along the axial direction. The first section 14a extends axially between the axial end surface of the first end 13a and the second section 14b. The inner diameter of the first section 14a is larger than the inner diameter of the second section 14b, so that a step surface facing the first end 13a is formed at the junction of the first section 14a and the second section 14b. The propeller component 40 is installed in the first section 14a and abuts the step surface axially. This prevents the propeller component 40 from axially crossing the step surface and entering the second section 14b, thereby limiting the axial position of the propeller component 40.

The electric oil pump according to the present invention can pump oil into the motor cavity through the propeller fan component, thereby improving the cooling effect of the drive motor and ensuring the working efficiency of the drive motor. Since the pump suction is generated by the motor shaft driving the propeller fan component to rotate, the oil inlet hole of the motor shaft does not need to be connected to the high-pressure chamber of the pump rotor assembly, thereby avoiding affecting the pumping efficiency of the pump rotor assembly. The oil inlet hole can directly draw oil from the oil supply chamber to cool the drive motor. The oil in the chamber can also be further circulated back into the low-pressure chamber. This can advantageously improve the volumetric efficiency of the electric oil pump. Furthermore, this propeller fan component has a simple structure and is easy to install, with low production costs, thus having high applicability.

While the foregoing descriptions illustrate possible embodiments, it should be understood that numerous variations exist through combinations of all known and other technical features and implementations readily conceivable to a skilled artisan. Furthermore, it should be understood that the exemplary embodiments serve merely as examples and in no way limit the scope, application, or configuration of the present invention. The foregoing descriptions are intended primarily to provide a skilled artisan with technical guidance for implementing at least one exemplary embodiment. Various modifications, particularly regarding the functionality and structure of the components described, may be made without departing from the scope of the claims.

Reference Signs
10. Drive motor
11 stator
12 rotors
13 Motor shaft
13a First end
13b Second end
14 Oil inlet hole
14a First Section
14b Second Section
20 Pump rotor assembly
30 Shell
31 Main body
31a Partition wall
31b oil outlet
32 Pump head cover
32a Oil inlet hole
40 Propeller fan components
41 Connection
42 fan blades
Ch high pressure chamber
Cl low pressure chamber
Cm motor cavity
Cs oil supply chamber

Claims (10)

An electric oil pump comprises a drive motor (10), a pump rotor assembly (20) and a housing (30), wherein the housing (30) comprises a motor cavity (Cm) for accommodating the drive motor (10), the drive motor (10) comprises a motor shaft (13) drivingly connected to the pump rotor assembly (20) to drive the pump rotor assembly (20), and the motor shaft (13) comprises an oil inlet hole (14) axially penetrating and communicating with the motor cavity (Cm). It is characterized by: The electric oil pump further includes a propeller fan component (40), which is fixedly mounted in the oil inlet hole (14) so that the propeller fan component (40) can generate a pumping suction force toward the motor cavity (Cm) as the motor shaft (13) rotates relative to the housing (30). The electric oil pump according to claim 1 is characterized in that the pump rotor assembly (20) includes a low-pressure chamber (Cl) for sucking in oil and a high-pressure chamber (Ch) for pumping out the sucked-in oil, the electric oil pump includes an oil supply chamber (Cs) connected to the low-pressure chamber (Cl) to supply oil to the pump rotor assembly (20), and the oil inlet hole (14) is connected to the oil supply chamber (Cs) to pump oil from the oil supply chamber (Cs) to the motor chamber (Cm). The electric oil pump according to claim 2, characterized in that the motor chamber (Cm) is connected to the low-pressure chamber (Cl) so that the oil in the motor chamber (Cm) can flow into the low-pressure chamber (Cl). The electric oil pump according to claim 2 is characterized in that the motor shaft (13) includes a first end (13a) and a second end (13b) opposite to each other in the axial direction, the first end (13a) is transmission-connected to the pump rotor assembly (20), the second end (13b) extends into the motor cavity (Cm), and the propeller member (40) is mounted radially inward of the first end (13a). The electric oil pump according to claim 4, characterized in that the propeller fan component (40) does not extend beyond the first end (13a) in the axial direction. According to the electric oil pump of claim 4, the oil inlet hole (14) includes a first section (14a) and a second section (14b) divided in the axial direction, the first section (14a) is located in the second section (14b). An axial end surface of one end (13a) extends axially between the second section (14b), and the inner diameter of the first section (14a) is larger than the inner diameter of the second section (14b), so that a step surface toward the first end (13a) is formed at the junction of the first section (14a) and the second section (14b), and the fan component (40) is installed in the first section (14a) and abuts the step surface. The electric oil pump according to any one of claims 2 to 6 is characterized in that the propeller fan component (40) includes a connecting portion (41) and a plurality of blades (42) respectively connected to the connecting portion (41), and the plurality of blades (42) are distributed at intervals in the circumferential direction around the rotation axis of the motor shaft (13) and are inclined in the same direction in the circumferential direction, so that the propeller fan component (40) generates a pump suction force toward the motor cavity (Cm) when the motor shaft (13) rotates in a predetermined rotation direction. The electric oil pump according to claim 7, characterized in that the propeller fan component (40) has one of the following structures: The connecting portion (41) is a connecting ring extending around the rotation axis of the motor shaft (13) and fixed to the inner wall of the oil guide hole (14); the plurality of blades (42) respectively extend radially inward from the connecting portion (41); The connecting portion (41) is a connecting column extending axially along the rotation axis of the motor shaft (13); the plurality of fan blades (42) respectively extend radially outward from the connecting portion (41) and are fixed to the inner wall of the oil guide hole (14); and The connecting portion (41) extends parallel to the rotation axis of the motor shaft (13), and the plurality of blades (42) are respectively connected to the same axial end of the connecting portion (41). The electric oil pump according to claim 8 is characterized in that the connecting portion (41) is a connecting plate extending parallel to the rotation axis of the motor shaft (13), and the propeller fan component (40) includes two blades (42), and the two blades (42) are sheet-like structures extending from the same axial end of the connecting portion (41) and inclined in opposite directions relative to the extension plane of the connecting portion (41). The electric oil pump according to claim 9, characterized in that the two blades (42) are connected to the axial end portion of the connecting portion (41) facing the first end (13a).