Fluid delivery device

Abstract

A fluid delivery device has a primary pump and a main pump fluidically connected to the primary pump. The primary pump can be driven by a primary pump input shaft, the main pump can be driven by a main pump input shaft, and the primary pump input shaft and the main pump input shaft are mechanically coupled to a common drive shaft of the fluid delivery device. The primary pump is in the form of a non-compensated gear pump or a centrifugal pump and the main pump is in the form of a compensated internal gear pump.

Claims

1. A fluid delivery device comprising: a primary pump driven by a primary pump input shaft; and a main pump fluidically connected to the primary pump, the main pump driven by a main pump input shaft, and the primary pump input shaft and the main pump input shaft are mechanically coupled to a common drive shaft of the fluid delivery device, wherein the primary pump is a non-compensated gear pump and the main pump is a compensated internal gear pump, wherein the primary pump has a higher limit speed and a larger pump volume than the main pump, wherein the primary pump, configured as an internal gear pump, includes at least one of: a suction chamber that extends over an angular range larger than a suction chamber of the main pump; and a pressure chamber that extends over at least a same angular range as a pressure chamber of the main pump.

2. The fluid delivery device according to claim 1, wherein the primary pump has a primary pump sprocket and a primary pump hollow wheel, and the main pump has a main pump sprocket and a main pump hollow wheel, wherein the primary pump sprocket and the main pump sprocket are arranged coaxially and the primary pump hollow wheel and the main pump hollow wheel are arranged to be radially offset from one another.

3. The fluid delivery device according to claim 1, wherein the primary pump and the main pump are arranged in a common machine housing.

4. The fluid delivery device according to claim 1, wherein the angular range over which the suction chamber of the primary pump extends in a circumferential direction, is at least 180°.

5. The fluid delivery device according to claim 1, wherein the angular range over which the suction chamber of the primary pump extends in a circumferential direction, is at least 190°.

6. The fluid delivery device according to claim 1, wherein the angular range over which the suction chamber of the primary pump extends in a circumferential direction, is at least 200°.

7. The fluid delivery device according to claim 1, wherein the angular range over which the suction chamber of the primary pump extends in a circumferential direction, is at least 210°.

8. The fluid delivery device according to claim 1, wherein the angular range over which the suction chamber of the primary pump extends in a circumferential direction, is at least 220°.

9. The fluid delivery device according to claim 1, wherein the angular range over which the suction chamber of the primary pump extends in a circumferential direction, is at least 225°.

10. A fluid delivery device comprising: a primary pump driven by a primary pump input shaft; and a main pump fluidically connected to the primary pump, the main pump driven by a main pump input shaft, and the primary pump input shaft and the main pump input shaft are mechanically coupled to a common drive shaft of the fluid delivery device, wherein the primary pump is a non-compensated gear pump and the main pump is a compensated internal gear pump, wherein the primary pump has a higher limit speed and a larger pump volume than the main pump, and wherein a primary pump filler piece is arranged in the primary pump configured as an internal gear pump between a primary pump sprocket and a primary pump hollow wheel, and a main pump filler piece is arranged in the main pump between a main pump sprocket and a main pump hollow wheel, wherein the primary pump filler piece has a smaller angular extension in a circumferential direction with respect to a rotational axis of the primary pump sprocket than the main pump filler piece in the circumferential direction with respect to a rotational axis of the main pump sprocket.

11. The fluid delivery device according to claim 10, wherein the primary pump filler piece, the primary pump sprocket, and the primary pump hollow wheel provide at least one of a sealing effect between the primary pump filler piece and the primary pump sprocket and a sealing effect between the primary pump filler piece and the primary pump hollow wheel on a side of the primary pump filler piece facing a pressure chamber is larger than on a side of the primary pump filler piece facing a suction chamber.

12. The fluid delivery device according to claim 10, wherein, prior to start-up, the primary pump sprocket is designed to be oversized with respect to the primary pump filler piece, so that a running-in wear occurs during running-in, resulting in a lit free of play.

13. The fluid delivery device according to claim 10, wherein, prior to start-up, the primary pump hollow wheel is designed to be undersized with respect to the primary pump filler piece, so that a running-in wear occurs during running-in, resulting in a fit free of play.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the following, the invention shall be described in more detail using the embodiments shown in the drawings, without restricting the invention. In the drawings:

(2) FIG. 1 shows a schematic longitudinal section of a fluid delivery device having a primary pump and a main pump;

(3) FIG. 2 is a schematic cross-sectional view of the fluid delivery device;

(4) FIG. 3 is a schematic cross-sectional view of the fluid delivery device in the region of the primary pump; and

(5) FIG. 4 shows a schematic longitudinal section of the fluid delivery device in a further embodiment.

DETAILED DESCRIPTION

(6) FIG. 1 shows a schematic longitudinal section of a fluid delivery device 1 having a primary pump 2 and a main pump 3 fluidically connected to the primary pump 2. The fluid delivery device 1 has a fluid inlet 4 and a fluid outlet 5 and is configured such that it delivers fluid from the fluid inlet 4 in the direction of the fluid outlet 5. The primary pump 2 is directly fluidically connected to the fluid inlet 4, but only indirectly to the fluid outlet 5 via the main pump 3. Conversely, the main pump 3 is only indirectly connected to the fluid inlet 4 via the primary pump 2, but directly to the fluid outlet 5. This means that the fluid provided at the fluid inlet 4 is delivered by the primary pump 2 in the direction of the main pump 3 and from the main pump 3, it is delivered in the direction of the fluid outlet 5, where it is subsequently available.

(7) The primary pump 2 and the main pump 3 are arranged in a common machine housing 6 or pump housing, on which both the fluid inlet 4 and the fluid outlet 5 are formed. A drive shaft 7, by means of which a primary pump input shaft 8 and a main pump input shaft 9 can be driven, is rotatably mounted in the machine housing 6. In the herein depicted embodiment, the primary pump input shaft 8 is integral with, and/or made of the same material as, the main pump input shaft 9. The drive shaft 7 is preferably non-rotatably coupled to the primary pump input shaft 8 and the main pump input shaft 9 via an interlocking connection, for example, a toothed connection. The primary pump 2 has a primary pump sprocket 10 and a primary pump hollow wheel 11 and is configured as an internal gear pump. In this respect, the primary pump sprocket 10 has an external toothing 12, which intermeshes in regions with an internal toothing 13 of the primary pump hollow wheel 11 for delivering the fluid. In the herein depicted embodiment, the primary pump sprocket 10 is non-rotatably connected to the primary pump input shaft 8, but it is movably connected in the axial direction. However, it can also be provided that the primary pump sprocket 10 is integral with, and/or made of the same material as, the primary pump input shaft 8. Alternatively, the primary pump 2 can be in the form of an external gear pump or a centrifugal pump.

(8) The main pump 3 has a main pump sprocket 14 and a main pump hollow wheel 15. The main pump sprocket 14 has an external toothing 16 which, as seen looking in the circumferential direction, intermeshes only in regions with an internal toothing 17 of the main pump hollow wheel 15. In the primary pump 2, a suction chamber 18 is located in the radial direction between the primary pump sprocket 10 and the primary pump hollow wheel 11. This also applies to a pressure chamber 19. The suction chamber 18 is directly fluidically connected to the fluid inlet 4, wherein the primary pump 2 is configured such that the fluid, as seen looking in the axial direction, can flow into the suction chamber 18 on both sides. Accordingly, a flow connection is present from the fluid inlet 4 to both sides of the suction chamber 18. The pressure chamber 19 is fluidically connected to the main pump 3 via a flow channel 20 formed in the machine housing 6, i.e., it is connected to a suction chamber 21 of the main pump, which is located in the radial direction between the main pump sprocket 14 and the main pump hollow wheel 15.

(9) The main pump 3 is configured such that the flow channel 20, as seen looking in the axial direction, is fluidically connected to the suction chamber 21 on both sides, so that fluid, as seen looking in the axial direction, can flow from the flow channel 20 on both sides into the suction chamber 21 of the main pump 3. In addition, recesses 22 are formed in the main pump hollow wheel 15, via which an additional flow connection between the flow channel 20 and the suction chamber 21 is present. The main pump 3 also has a pressure chamber 23 which is located in the radial direction between the main pump sprocket and the main pump hollow wheel 15. The pressure chamber 23 has, preferably exclusively, a flow connection to the fluid outlet 5 via the recesses 22. This means that fluid present in the pressure chamber 23 can escape from the pressure chamber 23 in the direction of the fluid outlet 5 exclusively via at least one of the recesses 22.

(10) In the herein depicted embodiment, the main pump 3 is at least axially compensated, i.e., it has an axial compensation 24. For this purpose, as seen looking in the axial direction, one axial disk 25 each is arranged on both sides of the main pump sprocket 14 and the main pump hollow wheel 15, which are pushed in the direction of the main pump sprocket 14 and the main pump hollow wheel 15 during operation of the main pump 3 and bear in a sealing manner against the front sides of the main pump sprocket 14 and the main pump hollow wheel 15. For this purpose, pressure from the pressure chamber 23 of the main pump 3 is applied to the axial disks 25. For example, an opening 26 is formed for this purpose in the axial disks 25, via which the pressure chamber 23 is in flow connection with a pressure field 27 which is present on the side of the axial disk facing away from the pressure chamber 23.

(11) FIG. 2 is a schematic cross-sectional view of the fluid delivery device 1, wherein the primary pump sprocket 10, the primary pump hollow wheel 11, the main pump sprocket 14 and the main pump hollow wheel 15 are shown. The primary pump sprocket 10 is rotatably mounted about a rotational axis 28 of the primary pump sprocket, the primary pump hollow wheel 11 is rotatably mounted about a rotational axis 29 of the primary pump hollow wheel, the main pump sprocket 14 is rotatably mounted about a rotational axis 30 of the main pump sprocket, and the main pump hollow wheel 15 is rotatably mounted about a rotational axis 31 of the main pump hollow wheel. It can be seen that the rotational axis 28 of the primary pump sprocket and the rotational axis 30 of the main pump sprocket are identical, so that the primary pump sprocket 10 and the main pump sprocket 14 are arranged coaxially to one another. The rotational axis 29 of the primary pump hollow wheel is arranged at a distance parallel to the rotational axis 28 of the primary pump sprocket, and the rotational axis 31 of the main pump hollow wheel is arranged at a distance parallel to the rotational axis 30 of the main pump sprocket.

(12) In the herein depicted embodiment of the fluid delivery device 1, the rotational axis 31 of the main pump hollow wheel and the rotational axis 29 of the primary pump hollow wheel are arranged on opposite sides of the rotational axis 28 of the primary pump sprocket. In other words, the rotational axis 28 of the primary pump sprocket, the rotational axis 29 of the primary pump hollow wheel, the rotational axis 30 of the main pump sprocket, and the rotational axis 31 of the main pump hollow wheel lie on an imaginary straight line, wherein the rotational axis 29 of the primary pump hollow wheel and the rotational axis 31 of the main pump hollow wheel are arranged on opposite sides of the rotational axis 28 of the primary pump sprocket and are particularly preferably arranged at the same distance a from it. It can be provided—as shown here—that teeth of the primary pump sprocket 10 and teeth of the main pump sprocket 14 are arranged offset from one another in the circumferential direction, i.e., as seen looking in the axial direction, they do not overlap and are not aligned with one another. As a result, the occurrence of pulsations can effectively be avoided. For example, an offset of half a tooth distance is provided, so that each tooth of the primary pump sprocket 10 lies centrally between two teeth of the main pump sprocket 14, or vice versa. However, any other offset in the circumferential direction can also be selected.

(13) FIG. 3 is a schematic cross-sectional view of the fluid delivery device 1 in the region of the primary pump 2. It shows the primary pump input shaft 8, the primary pump sprocket 10, and the primary pump hollow wheel 11, which are arranged in the machine housing 6. Between the primary pump sprocket 10 and the primary pump hollow wheel 11, a primary pump filler piece 32, shown herein in two different positions, is arranged for the fluidic separation of the suction chamber 18 from the pressure chamber 19. A main pump filler piece is shown at reference character 32′. It can be seen that the primary pump filler piece 32 has a comparatively small extension or angular extension in the circumferential direction. Correspondingly, the angular range a, over which the suction chamber 18 extends in the circumferential direction, is very large for both arrangements of the primary pump filler piece 32 and is at least 150°, preferably at least 180°, or more than 180°. As a result, a particularly rapid filling of the suction chamber 18 with fluid is ensured.

(14) It is clear from the figures described that the primary pump 2 is configured to be non-compensated and, in the herein depicted embodiment, has neither an axial compensation nor a radial compensation. However, the main pump is configured to be compensated and, in the herein depicted embodiment, has at least the axial compensation 24. Additionally or alternatively, the main pump 3 can be designed with a radial compensation. The described configuration of the fluid delivery device 1 allows for a particularly high speed, particularly of the primary pump 2. This ensures a reliable supply of fluid to the main pump 3, so that overall the fluid delivery device 1 realizes a high delivery pressure or a large pressure ratio between the pressure at the fluid outlet 5 and the pressure at the fluid inlet 4.

(15) FIG. 4 shows a schematic longitudinal section of the fluid delivery device 1 in a further embodiment. It corresponds in essential parts to the previously described fluid delivery device 1, so that reference is made to the corresponding statements and only the differences shall be described in the following. Said differences are that the primary pump 2 is not configured as an internal gear pump, but as a centrifugal pump. The primary pump 2, configured as a centrifugal pump, has an impeller 33, which in the herein depicted embodiment is present as a radial pump impeller. Accordingly, the centrifugal pump is configured as a radial pump. The impeller 33 has a diameter D.sub.1 which, in the herein depicted embodiment, corresponds to an outer diameter D.sub.2 of the main pump hollow wheel 15. In any case, however, the diameter D.sub.1 of the impeller 33 corresponds to maximally 125% of the outer diameter D.sub.2 of the main pump hollow wheel 15. It can be seen that the impeller 33 of the primary pump 2 is once again arranged coaxially to the main pump sprocket 14. As a result, a particularly compact design of the fluid delivery device 1 is achieved.