Fluid pump

Abstract

A fluid pump (10) comprises a housing (12), an inner rotor (14) located in the housing (12), and an outer rotor (16) surrounding the inner rotor (14), the outer rotor (16) being rotatably mounted in the housing (12) and forming an inner ring gear pump together with the inner rotor (14), where the outer rotor (16) is provided with teeth (18) with which a drive gear (20) meshes.

Description

Technical Field

[0001] The invention relates to a fluid pump, which comprises a housing, an inner rotor located in the housing, and an outer rotor surrounding the inner rotor. The outer rotor is rotatably mounted in the housing and forms an internal gear ring pump together with the inner rotor. Background Art

[0002] Internal ring gear pumps can be used, in particular, in motor vehicles for pumping liquid media, such as oil or cooling water.

[0003] Usually, in the case of such an internal gear pump, the inner rotor is driven by a drive motor, particularly an electric motor. In this respect, the inner rotor rotates at the same speed as the drive motor.

[0004] Generally, internal gear pumps have a disadvantage in terms of efficiency if the medium being pumped has a high viscosity, since in this case a higher torque of the drive motor is required in order to be able to maintain a constant rotational speed.

[0005] However, for the drive motor, a higher rotational speed with as low a torque as possible would be advantageous. Summary of the Invention

[0006] It is therefore an object of the present invention to provide a more efficient fluid pump for pumping liquid media.

[0007] According to the present invention, this object is achieved by a fluid pump, which includes a housing, an inner rotor located in the housing, and an outer rotor surrounding the inner rotor, the outer rotor being rotatably mounted in the housing and forming an internal gear ring pump together with the inner rotor, wherein the outer rotor is provided with a tooth portion with which a drive gear meshes.

[0008] In this way, a transmission mechanism is implemented within the fluid pump. This allows the drive device of the fluid pump, in particular the electric motor used for driving purposes, to operate within a range of rotational speeds that has a favorable effect on the efficiency of the fluid pump. More specifically, the electric motor can operate at relatively high rotational speeds combined with low torque.

[0009] This allows the fluid pump according to the invention to be operated efficiently even when pumping highly viscous media.

[0010] A further advantage of this is that by operating the electric motor in an optimum rotational speed range, a compact and cost-effective design is possible, since more cost-effective permanent magnets can be used in the electric motor.

[0011] The desired transmission ratio from the electric motor to the external rotor can be defined by the corresponding configuration of the teeth on the drive gear and the external rotor.

[0012] According to one embodiment, the toothing of the outer rotor is an internal toothing. This contributes to a compact design, since the drive gear is inside the outer rotor.

[0013] The internal gearing of the drive gear and the external rotor can form an internal gear pump. This is a gear mechanism that reduces the rotational speed of the electric motor to the external rotor. A particular advantage is that the internal gear pump can function both as a transmission and as an additional pump stage. This further increases the efficiency of the fluid pump and allows for higher volume flows.

[0014] Furthermore, the use of an internal gear pump as an additional pump stage makes it possible to reduce the length of the internal gear pump, thus contributing to a compact design.

[0015] The first housing wall adjacent to the inner rotor, for example, has a main inlet opening and a main outlet opening. These openings serve as the inlet and outlet openings for the internal gear pump. Alternatively, the internal gear pump can also draw liquid through the main inlet opening, particularly if the internal gear pump and the internal gear pump are not fluidically separated from each other.

[0016] The first housing wall can be formed by a cover or a bottom of the housing.

[0017] In particular, bearing journals for radially mounting the inner rotor are arranged on the first housing wall, so that the inner rotor can be positioned particularly easily in the housing.

[0018] The bearing journal is preferably formed integrally with the housing wall, thereby reducing the number of components and making assembly of the fluid pump easier.

[0019] According to one embodiment, a second housing wall of the housing, adjacent to the inner gearing of the outer rotor, has an additional inlet opening and an additional outlet opening, which at least partially overlap the drive gear. These form the inlet opening and outlet opening for the internal gear pump, allowing the ring gear pump and the internal gear pump to pump fluid separately from each other.

[0020] For the fluid separation between the internal gear pump and the internal gear pump, an axial wall can be formed in the outer rotor between the inner gear of the inner rotor and the inner gear of the outer rotor. This wall is preferably formed integrally in the outer rotor.

[0021] The second housing wall of the housing adjacent to the inner toothing may have a sickle-shaped projection between the inner toothing of the outer rotor and the drive gear. The sickle-shaped projection is used to seal the teeth of the drive gear and the inner toothing, so that the liquid to be pumped can be pumped into the two spaces between the tooth gaps of the drive gear and the inner toothing.

[0022] The sickle-shaped projection can also be omitted. In this case, the internal toothing and the gear are only used as a transmission mechanism, rather than being used to pump liquid.

[0023] According to another embodiment, the toothing of the outer rotor is an external toothing. In this case, the drive gear is located outside the outer rotor, which provides a particularly high flexibility in terms of possible transmission ratios.

[0024] For example, the drive shaft extends through the housing, and the inner rotor is floatingly mounted on the drive shaft. Therefore, in this case, a separate bearing journal for mounting the inner rotor is not required, thereby contributing to a simple design of the fluid pump.

[0025] If the drive gear is outside the outer rotor, the drive gear can be part of an at least two-stage gear mechanism, so that the transmission ratio between the electric motor and the inner rotor of the internal gear pump can be selected with high flexibility.

[0026] The drive gear can have a first toothing and a second toothing axially offset from the first toothing, wherein the first toothing and the second toothing have different numbers of teeth. Such a two-stage gear results in a smaller installation space being occupied.

[0027] Preferably, the second tooth portion of the drive gear extends into the housing so that the drive gear can directly mesh with the outer tooth portion of the outer rotor, thereby contributing to a compact design.

[0028] The bearing journal can be molded onto the drive gear, which is radially mounted in the housing. The housing has corresponding cutouts for this purpose. This ensures that the drive gear is stably supported in the radial direction and reliably maintains meshing with the outer gearing of the outer rotor. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Further advantages and features of the present invention can be found in the following description and in the accompanying drawings for reference. In the drawings:

[0030] - Figure 1 shows an exploded view of a fluid pump according to the present invention,

[0031] - Figure 2 Shown Figure 1 Subassemblies of fluid pumps,

[0032] - Figure 3 Shown Figure 1 Cross-section of the fluid pump,

[0033] - Figure 4 Shown Figure 1 Front view of the fluid pump,

[0034] - Figure 5 Shown Figure 1 The housing of the fluid pump,

[0035] - Figure 6 Another embodiment of the fluid pump according to the present invention is shown.

[0036] - Figure 7 Shown Figure 6 Cross-section of the fluid pump,

[0037] - Figure 8 Shown Figure 6 Rear view of the fluid pump,

[0038] - Figure 9 shows a perspective view of another embodiment of a fluid pump according to the present invention,

[0039] - Figure 10 Shown Figure 9 Exploded view of the fluid pump.

[0040] - Figure 11 Shown Figure 9 A cross-sectional view of the fluid pump, and

[0041] - Figure 12 Shown Figure 9 Front view of the fluid pump. DETAILED DESCRIPTION

[0042] Figure 1 Shown is an exploded view of a fluid pump 10. The fluid pump 10 is used to pump a liquid medium, such as oil or cooling water.

[0043] The fluid pump 10 includes a housing 12 , an inner rotor 14 located in the housing 12 , and an outer rotor 16 surrounding the inner rotor 14 .

[0044] The outer rotor 16 is rotatably mounted in the housing 12 .

[0045] Outer rotor 16 and inner rotor 14 together form an internal gear pump. In the exemplary embodiment, the internal gear pump is in the form of a gerotor pump. Outer rotor 16 thus has inwardly extending protrusions, while inner rotor 14 has an outer profile with outwardly extending protrusions 22 that interact appropriately with the inner profile of outer rotor 16. The mode of operation of such pumps is well known, and therefore a detailed description will be omitted here.

[0046] The outer rotor 16 is provided with a toothing 18 , more specifically an internal toothing.

[0047] The driving gear 20 meshes with the toothed portion 18. Figure 2 The drive gear 20 serves to drive the outer rotor 16. The drive gear 20, together with the toothing 18, forms a gear stage of a reduction mechanism, by means of which the rotational speed of a drive shaft 23, on which the drive gear 20 is mounted for co-rotation, can be reduced.

[0048] When the outer rotor 16 is driven, it also drives the inner rotor 14 via the interacting protrusions.

[0049] The drive gear 20 and the inner gear portion 18 of the outer rotor 16 also form an internal gear pump, which is similar to the internal gear ring pump formed by the inner rotor 14 and the outer rotor 16 and can be used to pump fluid. Figure 3 The drive gear 20 extends into the outer rotor 16 at one axial end thereof, and the remaining axial space of the outer rotor 16 is occupied by the inner rotor 14, so that the inner rotor 14 extends to the axial end of the outer rotor 16 opposite to the drive gear 20.

[0050] In order to drive the fluid pump 10, a Figure 3 The electric motor 25 is schematically shown in FIG.

[0051] An electric motor 25 drives a drive shaft 23 that extends into the housing 12 and on which the drive gear 20 is located for common rotation.

[0052] The drive shaft 23 and thus the drive gear 20 are eccentric relative to the outer rotor 16 .

[0053] The housing 12 has a first housing wall 24 adjoining the inner rotor 14 and a second housing wall 26 adjoining the inner toothing 20 of the outer rotor 16 .

[0054] In the exemplary embodiment, the first housing wall 24 is formed by a separate housing cover 28 and the second housing wall 26 is formed by a bottom 30 produced integrally with the housing 12. However, the arrangement of housing cover and housing bottom shown in the figures can also be reversed.

[0055] The first housing wall 24 , ie the housing cover 28 , has a bearing journal 32 which is formed integrally with the first housing wall 24 .

[0056] The bearing journal 32 is used for radially mounting the inner rotor 14 .

[0057] The inner rotor 14 is axially mounted via two housing walls 24 , 26 , between which the inner rotor 14 is located. This also applies to the outer rotor 16 .

[0058] The first housing wall 24 has a main inlet opening 34 and a main outlet opening 36, as shown in FIG. Figure 1 and Figure 4 shown.

[0059] The side of the second housing wall 26 facing the interior space of the housing 12, ie the housing bottom 30, has a sickle-shaped projection 38, such as Figure 5 In the installed state, the projection 38 is located between the inner toothing of the outer rotor 16 and the drive gear 20. It separates the suction side of the gear pump 18, 20 from the pressure side.

[0060] When the fluid pump 10 is running, the internal gear pump and the internal gear pump pump the liquid together, and the internal gear pump and the internal gear pump pump in the same direction. The internal gear pump and the internal gear pump can therefore be regarded as separate pump stages of the fluid pump 10.

[0061] The speed reduction from gear 20 to outer rotor 16 reduces the rotational speed of electric motor 25 , for example a 2:1 or 3:1 ratio, transmitted to inner rotor 14 .

[0062] The total reduction ratio from the electric motor 25 to the inner rotor 14 is given by the reduction ratio from the gear 20 to the outer rotor multiplied by the reduction ratio between the outer rotor 16 and the inner gear ring of the inner rotor 14 .

[0063] In accordance with Figures 1 to 5 In the exemplary embodiment of FIG. 5 , the main inlet opening 34 and the main outlet opening 36 constitute a common suction opening or discharge opening for both pump stages.

[0064] The individual components of the fluid pump, in particular the housing 12 , the inner rotor 14 , the outer rotor 16 and the drive gear 20 , are, for example, injection-molded components, in particular plastic injection-molded components. However, one or more components may also be made of metal.

[0065] Figures 6 to 8 Another embodiment of a fluid pump 10 is shown.

[0066] Figures 6 to 8 The fluid pump 10 shown is Figures 1 to 5 The fluid pump 10 shown is only slightly different.

[0067] On the one hand, an axial wall 40 is located in the outer rotor 16. The wall 40 is in particular formed integrally with the outer rotor 16.

[0068] The wall 40 is located between the teeth 18 of the inner rotor 14 and the outer rotor 16 , so that the wall 40 fluidically separates the ring gear pump and the internal gear pump from one another.

[0069] Therefore, according to Figures 6 to 8 In the embodiment of FIG. 4 , the second housing wall 26 of the housing 12 has, in addition to the main inlet opening 34 and the main outlet opening 36 , which in this case are assigned to the ring gear pump, an additional inlet opening 42 and an additional outlet opening 44 formed therein.

[0070] An additional inlet opening 42 and an additional outlet opening 44 are assigned to the internal gear pump, so that the latter can suck in and discharge liquid through the openings 42 , 44 , respectively.

[0071] To this end, the additional inlet opening 42 and the additional outlet opening 44 at least partially overlap the drive gear 20, as shown in FIG. Figure 8, wherein a portion of the toothing of the drive gear 20 and a portion of the toothing 18 of the outer rotor 16 can be seen through the openings 42 , 44 .

[0072] In accordance with Figures 1 to 5 The case of the fluid pump 10 and according to Figures 6 to 8 In the case of the fluid pump 10 , it is possible to short-circuit the internal gear pump so that it no longer contributes to the volume pumped by the fluid pump 10 but instead serves purely as a transmission mechanism.

[0073] In order to short-circuit the internal gear pump, the sickle-shaped projection can be made smaller or omitted entirely.

[0074] In accordance with Figures 1 to 5 In the case of the fluid pump 10, it is also conceivable to make the sickle-shaped protrusion 38 shorter, thereby resulting in a more kidney-shaped profile of the protrusion, such as Figure 5 In this case, the internal gear pump can suck liquid through the main inlet opening 34 and the additional inlet opening 42.

[0075] Figures 9 to 12 Another embodiment of a fluid pump 10 is shown.

[0076] For identical structures known from the above embodiments and having the same function, the same reference numerals are used below, and in this respect reference is made to the explanations given above.

[0077] In the following, in order to avoid repetition, only the differences between the various embodiments will be discussed.

[0078] from Figure 10 It can be clearly seen from the decomposition diagram that according to Figures 9 to 11 The fluid pump 10 further includes a housing 12 , an inner rotor 14 located in the housing 12 , an outer rotor 16 surrounding the inner rotor 14 and rotatably mounted in the housing 12 , a drive gear 20 , and an electric motor 25 .

[0079] Compared with the above embodiment, the tooth portion 18 of the outer rotor 16 with which the driving gear 20 meshes is an external tooth portion, for example Figure 10 shown.

[0080] Furthermore, no additional internal gear pump is implemented next to the internal ring gear pump.

[0081] A drive shaft 23 driven by an electric motor 25 extends through the housing 12 .

[0082] In particular, on the housing side facing away from the electric motor 25 , the drive shaft 23 projects beyond the housing 12 , ie beyond the first housing wall 24 .

[0083] In the housing 12, the inner rotor 14 is floatingly mounted on the drive shaft 23 (see Figure 11), so that the inner rotor 14 is radially fixed in place.

[0084] In this exemplary embodiment, the axial mounting of the inner rotor 14 and the outer rotor 16 is also achieved via the housing walls 24 , 26 .

[0085] Outside of the housing 12 , an intermediate gear 46 is mounted for common rotation on the drive shaft 23 .

[0086] The intermediate gear 46 meshes with the drive gear 20 , so that torque can be transmitted from the electric motor 25 to the outer rotor 16 via the intermediate gear 46 and the drive gear 20 .

[0087] It is theoretically conceivable to provide a further intermediate gear which can be mounted, for example, on the first housing wall 24 or on the housing bottom 28 .

[0088] The drive gear 20 is therefore part of an at least two-stage gear mechanism.

[0089] like Figure 10 and Figure 12 As shown, the drive gear 20 has a first toothing 48 and a second toothing 50 axially offset from the first toothing 48 , wherein the first toothing 48 and the second toothing 50 have different numbers of teeth. In particular, the second toothing 50 has fewer teeth than the first toothing 48 .

[0090] In the exemplary embodiment, the drive gear 20 is manufactured in one piece, but manufacturing in multiple parts is also contemplated.

[0091] The second toothing 50 of the drive gear 20 extends into the housing 12 such that the second toothing 50 meshes with the external toothing of the outer rotor 16 .

[0092] Adjoining the second toothing 50 of the drive gear 20 is a bearing journal 52 , which is in particular molded in one piece with the drive gear.

[0093] like Figure 11 As shown, the bearing journal 52 is radially mounted in the housing 12. For this purpose, the housing 12 has a corresponding receptacle 54.

Claims

1. A fluid pump (10), comprising a housing (12), an inner rotor (14) located in the housing (12), and an outer rotor (16) surrounding the inner rotor (14), wherein the outer rotor (16) is rotatably mounted in the housing (12) and forms an inner ring gear pump together with the inner rotor (14), wherein: The outer rotor (16) is provided with a tooth portion (18), and the drive gear (20) is engaged with the tooth portion (18).

2. The fluid pump (10) according to claim 1, characterized in that The toothing (18) of the outer rotor (16) is an internal toothing.

3. The fluid pump (10) according to claim 2, characterized in that The drive gear (20) and the internal gear portion of the outer rotor (16) form an internal gear pump.

4. The fluid pump (10) according to any one of the preceding claims, characterized in that A first housing wall (24) adjacent to the inner rotor (14) has a main inlet opening (34) and a main outlet opening (36).

5. The fluid pump (10) according to claim 4, characterized in that The first housing wall (24) has a bearing journal (32) for radially mounting the inner rotor (14).

6. Fluid pump (10) according to any of the preceding claims and according to claim 2, characterized in that A second housing wall (26) of the housing (12) adjoining the inner toothing of the outer rotor (16) has an additional inlet opening (42) and an additional outlet opening (44), which at least partially overlap with the drive gear (20).

7. The fluid pump (10) according to claim 6, characterized in that Between the inner teeth of the inner rotor (14) and the outer rotor (16), an axial wall (40) is located in the outer rotor (16).

8. The fluid pump (10) according to claim 6 or 7, characterized in that A second housing wall (26) of the housing, adjacent to the inner toothing, has a sickle-shaped projection (38) between the inner toothing of the outer rotor (16) and the drive gear (20).

9. The fluid pump (10) according to claim 1, characterized in that The toothing (18) of the outer rotor (16) is an external toothing.

10. The fluid pump (10) according to claim 9, characterized in that A drive shaft (23) extends through the housing (12), and the inner rotor (14) is floatingly mounted on the drive shaft (23).

11. The fluid pump (10) according to claim 9 or 10, characterized in that The drive gear (20) is part of at least a two-stage gear mechanism.

12. The fluid pump (10) according to claim 11, characterized in that The drive gear (20) has a first toothing (48) and a second toothing (50) axially offset from the first toothing (48), wherein the first toothing (48) and the second toothing (50) have different numbers of teeth.

13. The fluid pump (10) according to claim 12, characterized in that The second tooth portion (50) of the drive gear (20) extends into the housing (12).

14. The fluid pump (10) according to any one of claims 9 to 12, characterized in that A bearing journal (52) is molded onto the drive gear (20), and the bearing journal (52) is radially mounted in the housing (12).

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