Internal gear pump

Abstract

An internal gear pump, comprising a driving shaft (13), a pump rotor assembly (20), and a housing (30). The driving shaft (13) and the pump rotor assembly (20) are each rotatably mounted to the housing (30) about an axial direction, the driving shaft (13) is drivingly connected to the pump rotor assembly (20) to drive the pump rotor assembly (20), the pump rotor assembly (20) comprises an outer ring gear (21) and an inner gear (22), and the inner gear (22) eccentrically meshes with and is arranged radially inside the outer ring gear (21) to generate a pumping force. The outer ring gear (21) is torsionally connected to the driving shaft (13), and the inner gear (22) is rotatably supported on a support structure fixed relative to the housing (30), such that the driving shaft (13) drives, by means of the outer ring gear (21), the inner gear (22) to rotate. Therefore, a support structure for the driving shaft can be reduced, making the internal gear pump easier to assemble.

Description

Internal gear pump Technical Field

[0001] The present invention relates to the technical field of oil pumps, and in particular to an internal gear pump. Background Art

[0002] An oil pump is a device used to drive fluid flow and generate fluid pressure in a mechanical system. For example, an electric oil pump is commonly used in current motor vehicles to drive working fluid for cooling and lubrication.

[0003] An internal gear pump is a widely used type of oil pump. The typical structure of an internal gear pump can be found in patent documents such as CN 116529487 A. An internal gear pump generally includes components such as a drive motor, a pump rotor assembly, and a housing. The pump rotor assembly includes an outer ring gear and an inner gear, and the inner gear is arranged on the radial inner side of the outer ring gear in an eccentrically meshed manner. When the two rotate relative to each other, pump suction can be generated. The motor shaft of the drive motor is connected to the inner gear of the pump rotor assembly as a drive shaft, so that the inner gear acts as a driving wheel to drive the outer ring gear to rotate.

[0004] In this type of prior art internal gear pump, the internal gear of the pump rotor assembly is fixedly connected to the motor shaft, thereby supporting the internal gear through the motor shaft. In this case, two bearings are typically required to support the motor shaft in the housing, which is costly and takes up a lot of space, resulting in a larger product size. Furthermore, when assembling this internal gear pump, the bearings must first be installed on the motor shaft, and then the internal gear must be installed on the motor shaft. The internal gear and motor shaft require an interference fit, and during installation, the bearings must withstand eccentric forces, thus posing a potential risk of bearing damage.

[0005] Summary of the Invention

[0006] Therefore, the technical problem to be solved by the present invention is to provide an internal gear pump with an improved structure.

[0007] The above technical problems are solved by an internal gear pump according to the present invention. The internal gear pump includes a drive shaft, a pump rotor assembly and a housing. The drive shaft and the pump rotor assembly are respectively mounted to the housing in a manner that can rotate around the axial direction. The drive shaft is transmission-connected to the pump rotor assembly to drive the pump rotor assembly. The pump rotor assembly includes an outer ring gear and an inner gear. The inner gear is arranged on the radial inner side of the outer ring gear in an eccentrically meshed manner to generate pump suction. The outer ring gear is torsionally connected to the drive shaft, and the inner gear is rotatably supported on a support structure fixed relative to the housing, so that the drive shaft can drive the inner gear to rotate via the outer ring gear. In this case, since the drive shaft is torsionally connected to the outer ring gear, the outer ring gear can provide support for the drive shaft, which facilitates the simplification of the support structure of the drive shaft and the installation process of the pump rotor assembly.

[0008] According to a preferred embodiment of the present invention, the outer ring gear can be rotatably supported on the housing, so that the housing can rotatably support the drive shaft via the outer ring gear. Since the outer ring gear is rotatably supported on the housing, the housing can rotatably support the drive shaft via the outer ring gear, thereby reducing the support structure for the drive shaft.

[0009] According to another preferred embodiment of the present invention, the inner surface of the housing, which supports the outer ring gear, can function as a sliding bearing, slidingly contacting the outer ring gear. This eliminates the need for additional rolling bearings between the housing and the outer ring gear to provide rotational support. Instead, the housing can directly slide and support the outer ring gear, which in turn supports the drive shaft via the outer ring gear. This reduces the number of rolling bearings supporting the drive shaft, thereby reducing product cost and size.

[0010] According to another preferred embodiment of the present invention, the internal gear pump may further include a support shaft as a support structure, wherein the internal gear is rotatably supported radially outwardly of the support shaft. The support shaft is directly or indirectly fixedly connected to the housing so that the internal gear can rotate relative to the housing.

[0011] According to another preferred embodiment of the present invention, the outer surface of the support shaft, which supports the internal gear, can function as a sliding bearing, slidingly contacting the internal gear. This eliminates the need for additional rolling bearings between the support shaft and the internal gear to provide rotational support. This eliminates the need for rolling bearings supporting the internal gear, reducing product cost and size.

[0012] According to another preferred embodiment of the present invention, the support shaft may have a central hole extending axially therethrough, thereby reducing the material required to manufacture the support shaft and reducing the weight of the support shaft.

[0013] According to another preferred embodiment of the present invention, the axial end of the support shaft away from the drive shaft can protrude axially beyond the internal gear and be fixed to the housing. The fixed connection between the support shaft and the housing can be achieved, for example, by interference fit.

[0014] According to another preferred embodiment of the present invention, the outer ring gear may include an engaging portion, a connecting portion, and a mounting portion. The mounting portion is fixed to the radially outer side of the axial end portion of the drive shaft facing the internal gear. The engaging portion surrounds the radially outer side of the internal gear and is axially located axially outward of the axial end portion of the drive shaft facing the internal gear. The connecting portion is radially connected between the engaging portion and the mounting portion. The outer ring gear is thus formed as a generally cylindrical component.

[0015] According to another preferred embodiment of the present invention, the internal gear may be constrained in the axial direction between a constraining structure fixed relative to the housing and the connecting portion, whereby the internal gear is fixed in the axial direction relative to the housing.

[0016] According to another preferred embodiment of the present invention, the drive shaft may not protrude axially beyond the connecting portion toward the internal gear; and / or the support structure may not protrude axially beyond the internal gear toward the drive shaft. This prevents interference between the drive shaft and the internal gear or the support structure, and / or interference between the support structure and the connecting portion or the drive shaft. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] 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.

[0018] FIG1 shows a longitudinal sectional view of an internal gear pump according to an exemplary embodiment of the present invention;

[0019] FIG2 is a schematic diagram illustrating an assembly of a pump rotor assembly to which an internal gear pump according to an exemplary embodiment of the present invention is applied;

[0020] FIG3 is a schematic diagram illustrating an assembly of an outer ring gear and a drive shaft to which an internal gear pump according to an exemplary embodiment of the present invention is applied; and

[0021] FIG. 4 is a schematic assembly diagram illustrating an internal gear and a support shaft to which an internal gear pump according to an exemplary embodiment of the present invention is applied. DETAILED DESCRIPTION

[0022] The following will describe a specific embodiment of the internal gear pump according to the present invention in conjunction with the accompanying drawings. The following detailed description and 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.

[0023] According to an embodiment of the present invention, an internal gear pump for driving a working fluid and generating fluid pressure is provided. Figures 1 to 4 illustrate an exemplary embodiment of the internal gear pump according to the present invention. The specific structure of the internal gear pump will be described below with reference to the accompanying drawings.

[0024] Figure 1 shows a longitudinal cross-sectional view of an internal gear pump according to an exemplary embodiment. As shown in Figure 1, this internal gear pump primarily comprises a drive assembly, a pump rotor assembly 20, and a housing 30. The drive assembly can be a built-in component capable of generating driving force, or it can be a transmission component that transmits external driving force to the pump rotor assembly 20. For example, in the embodiment shown in the figure, the drive assembly is schematically illustrated as a drive motor 10. The drive motor 10 includes a stator 11, a rotor 12, and a motor shaft 13. The stator 11 is fixed within the housing 30, and 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 fixed radially inwardly of the rotor 12, rotatable relative to the stator 11 and the housing 30 along the common central axis with the rotor 12. The motor shaft 13 protrudes axially beyond the drive motor 10 to provide a driving connection with 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 and may also be referred to as the drive shaft 13. It should be noted that while the drive motor 10 is described above as part of the internal gear pump, this is not restrictive. As previously mentioned, the internal gear pump may also include only the transmission component for transmitting the driving force to the pump rotor assembly 20, namely, the drive shaft 13. In other words, the source of the driving force does not constitute a limitation of the present invention.

[0025] The pump rotor assembly 20 is located at one axial end of the drive shaft 13 and is driven by the drive shaft 13 to generate pump suction. The pump rotor assembly 20 is mounted in the housing 30 and is rotatable relative to the housing 30 in the axial direction. The pump rotor assembly 20 includes an outer ring gear 21 and an inner gear 22. As shown in Figure 3, the outer ring gear 21 is generally cylindrical, with internal teeth formed radially inward. As shown in Figure 4, the inner gear 22 is generally disc-shaped, with external teeth formed radially outward. As shown in Figure 2, the internal teeth of the outer ring gear 21 mesh with the external teeth of the inner gear 22. The outer diameter of the inner gear 22 is smaller than the inner diameter of the outer ring gear 21, and the number of external teeth on the inner gear 22 is smaller than that on the outer ring gear 21. Consequently, the inner gear 22 is arranged radially inward of the outer ring gear 21 in an eccentric meshing arrangement to generate pump suction. In this eccentric meshing arrangement, the rotational axes of the outer ring gear 21 and the inner gear 22 extend parallel in the axial direction but are offset radially from each other. The meshing teeth of the outer gear ring 21 and the inner gear 22 can be either involute meshing teeth or cycloid meshing teeth. The working principle of generating pump suction is well known in the prior art and will not be described in detail here.

[0026] As shown in Figures 1 and 3 , the outer ring gear 21 is connected to the drive shaft 13 in a torsionally fixed manner, specifically, fixedly connected. The connection between the outer ring gear 21 and the drive shaft 13 can be achieved through various known methods, such as an interference fit and welding. This allows the outer ring gear 21 to rotate synchronously with the drive shaft 13 about a central axis parallel to the axial direction. As shown in Figures 1 and 4 , the internal gear 22 is rotatably supported on a support structure fixed relative to the housing 30, and can therefore also rotate relative to the housing 30 about its own central axis. The drive shaft 13 can thus drive the internal gear 22 in rotation via the outer ring gear 21.

[0027] The outer ring gear 21 can be rotatably supported on the housing 30. Since the outer ring gear 21 is directly connected to the drive shaft 13 as a driving wheel, the housing 30 can rotatably support the drive shaft 13 via the outer ring gear 21. In this way, at least a part of the support structure between the drive shaft 13 and the housing 30, in particular the rolling bearing, can be eliminated. Preferably, the inner surface of the housing 30 for supporting the outer ring gear 21 can slide in contact with the outer ring gear 21, that is, the inner surface of the housing 30 forms a sliding bearing supporting the outer ring gear 21. This means that there is no need to additionally arrange a rolling bearing between the housing 30 and the outer ring gear 21 to provide rotational support. In this way, the rolling bearing at the end of the drive shaft 13 facing the pump rotor assembly 20 can also be eliminated.

[0028] The support structure for the internal gear 22 can be part of the internal gear pump, such as the housing 30, or it can be another component that is not part of the internal gear pump itself but is fixedly assembled with the housing 30. For example, in this embodiment, the support structure can be a support shaft 33 fixed relative to the housing 30, with the internal gear 22 rotatably supported radially outwardly of the support shaft 33. The support shaft 33 can be considered a component of the internal gear pump, particularly the housing 30. Specifically, the housing 30 can include a generally cylindrical housing body 31 and an end cap 32 fixedly mounted to the housing body 31. The drive motor 10 and the pump rotor assembly 20 are mounted radially inwardly of the housing body 31. The end cap 32 is mounted to the axial end of the housing body 31 near the pump rotor assembly 20, thereby encapsulating the pump rotor assembly 20 within the housing 30. The support shaft 33 can be secured to the end cap 32 by interference fit, welding, or integral molding. The support shaft 33 is generally cylindrical in shape and extends axially from the end cap 32 toward the drive shaft 13. The support shaft 33 and the drive shaft 13 are axially offset from each other, and one axial end face of the support shaft 33 eccentrically faces the end face of the drive shaft 13 on which the pump rotor assembly 20 is mounted. Preferably, when the internal gear 22 is mounted on the support shaft 33, the axial end face of the support shaft 33 remote from the drive shaft 13 protrudes axially beyond the internal gear 22 so as to be fixed to the end cover 32 of the housing 30.

[0029] Preferably, the support shaft 33 may have a central hole 33a extending axially therethrough, so as to reduce material usage and product weight. Alternatively, the support shaft 33 may also be formed as a solid shaft.

[0030] Preferably, the outer surface of the support shaft 33 for supporting the internal gear 22 can slide in contact with the internal gear 22. That is, the outer surface of the support shaft 33 can be formed as a sliding bearing supporting the internal gear 22, so there is no need to additionally provide a rolling bearing between the support shaft 33 and the internal gear 22 to provide rotational support.

[0031] As shown in Figure 3, preferably, the outer ring gear 21 may include a meshing portion 21a, a connecting portion 21b and a mounting portion 21c. The mounting portion 21c is fixed to the radially outer side of the axial end portion of the drive shaft 13 facing the internal gear 22. The meshing portion 21a is formed into a roughly cylindrical shape, and the inner teeth of the outer ring gear 21 are formed on the radial inner surface of the meshing portion 21a. As shown in Figures 1 to 3, in the assembled state, the meshing portion 21a surrounds the radial outer side of the internal gear 22 and is axially located axially outside the axial end portion of the drive shaft 13 facing the internal gear 22. The inner diameter of the meshing portion 21a is generally larger than the outer diameter of the drive shaft 13 and the mounting portion 21c. The connecting portion 21b is roughly radially connected between the inner periphery of the meshing portion 21a and the outer periphery of the mounting portion 21c.

[0032] The internal gear 22 is axially constrained between a constraining structure fixed relative to the housing 30 and the connecting portion 21b. The constraining structure may be, for example, the end cover 32 of the housing 30. The constraining structure and the connecting portion 21b abut the internal gear 22 relative to each other, so that the internal gear 22 is fixed relative to the housing 30 in the axial direction but can rotate relative to the housing 30 around a central axis parallel to the axial direction. Preferably, the drive shaft 13 does not protrude axially beyond the connecting portion 21b toward the internal gear 22, thereby avoiding interference with the end face of the internal gear 22. Similarly, preferably, the support structure, in particular the support shaft 33, does not protrude axially beyond the internal gear 22 toward the drive shaft 13, thereby avoiding interference with the connecting portion 21b and the drive shaft 13.

[0033] In the internal gear pump of the present invention, the connection method between the pump rotor assembly and the drive shaft is changed. The outer ring gear of the pump rotor assembly is torsionally connected to the drive shaft, allowing the housing to support the drive shaft via the outer ring gear. This reduces the support structure for the drive shaft, particularly the rolling bearings. The outer ring gear has a larger sliding support surface, thus providing more stable support. This reduces the number of components and simplifies the structure of the internal gear pump, thereby reducing production costs and product size. Furthermore, this internal gear pump is also easier to assemble.

[0034] 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.

[0035] REFERENCE SIGNS LIST 10 Driving motor 11 Stator 12 Rotor 13 Driving shaft / motor shaft 20 Pump rotor assembly 21 Outer ring gear 21a Meshing portion 21b Connecting portion 21c Mounting portion 22 Internal gear 30 Housing 31 Housing body 32 End cover 33 Support shaft 33a Center hole

Claims

1. An internal gear pump, comprising a drive shaft (13), a pump rotor assembly (20) and a housing (30), wherein the drive shaft (13) and the pump rotor assembly (20) are respectively mounted to the housing (30) in a manner rotatable about an axial direction, the drive shaft (13) is transmission-connected with the pump rotor assembly (20) to drive the pump rotor assembly (20), the pump rotor assembly (20) comprising an outer gear ring (21) and an inner gear (22), the inner gear (22) being arranged radially inward of the outer gear ring (21) in an eccentrically meshed manner to generate pump suction, It is characterized by: The outer gear ring (21) is connected to the drive shaft (13) in a rotationally fixed manner, and the inner gear (22) is rotatably supported on a support structure fixed relative to the housing (30), so that the drive shaft (13) can drive the inner gear (22) to rotate via the outer gear ring (21).

2. The internal gear pump according to claim 1, characterized in that The outer ring gear (21) is rotatably supported on the housing (30), so that the housing (30) can rotatably support the drive shaft (13) via the outer ring gear (21).

3. The internal gear pump according to claim 2, characterized in that The inner surface of the housing (30) for supporting the outer gear ring (21) acts as a sliding bearing and slides in contact with the outer gear ring (21).

4. The internal gear pump according to claim 1, characterized in that The internal gear pump further includes a support shaft (33) as the support structure, and the internal gear (22) is rotatably supported on the radially outer side of the support shaft (33).

5. The internal gear pump according to claim 4, characterized in that The outer surface of the support shaft (33) for supporting the internal gear (22) acts as a sliding bearing and slides in contact with the internal gear (22).

6. The internal gear pump according to claim 5, characterized in that The support shaft (33) has a central hole (33a) extending axially therethrough.

7. The internal gear pump according to claim 4, characterized in that An axial end portion of the support shaft (33) remote from the drive shaft (13) protrudes axially out of the internal gear (22) and is fixed to the housing (30).

8. The internal gear pump according to any one of claims 1 to 7, characterized in that The outer gear ring (21) includes a meshing portion (21a), a connecting portion (21b) and a mounting portion (21c), wherein the mounting portion (21c) is fixed to the radially outer side of the axial end portion of the drive shaft (13) facing the internal gear (22), the meshing portion (21a) surrounds the radially outer side of the internal gear (22) and is axially located to the axially outer side of the axial end portion of the drive shaft (13) facing the internal gear (22), and the connecting portion (21b) is radially connected between the meshing portion (21a) and the mounting portion (21c).

9. The internal gear pump according to claim 8, characterized in that The internal gear (22) is constrained in the axial direction between a constraining structure fixed relative to the housing (30) and the connecting portion (21b).

10. The internal gear pump according to claim 9, characterized in that The drive shaft (13) does not protrude beyond the connecting portion (21b) toward the internal gear (22) in the axial direction; and / or The support structure does not protrude beyond the internal gear (22) in the axial direction toward the drive shaft (13).

Images