Support pockets

Abstract

Rotary pump with a housing (2) having a pumping chamber (1) having an inlet (5) for a fluid on a suction side of the rotary pump and an outlet (6) for the fluid on a pressure side of the rotary pump, an inner rotor (9) arranged in the pumping chamber (1), an outer rotor (10) arranged in the pumping chamber (1) and forming pumping cells (13) with the inner rotor (9), wherein the outer rotor (10) is slidably mounted with its outer circumferential wall (12) on an inner circumferential wall (11) of the pumping chamber (1), characterized in that the inner circumferential wall (11) of the pumping chamber (1) and / or the outer circumferential wall (12) of the outer rotor (10) has at least one pocket (7).

Description

[0001] The invention relates to a rotary pump with a housing comprising a pumping chamber with an inlet for a fluid on a suction side of the pump and an outlet for the fluid on a pressure side. An outer rotor and an inner rotor are mounted centrally and eccentrically within the pumping chamber, together forming pumping cells to convey the fluid from the suction side to the pressure side. The outer rotor comprises an outer circumferential wall which is slidably mounted on an inner circumferential wall of the pumping chamber, which is formed in particular by the housing.

[0002] Rotary pumps with external rotors, which are slidably mounted on the inner circumferential wall of a pumping chamber, can experience start-up problems, especially after extended periods of inactivity, if the outer rotor's outer surface is in almost complete contact with the inner circumferential wall of the pumping chamber. The static and / or frictional forces between the outer and inner surfaces of the rotor can be so high that initially, little or no fluid is pumped. This can lead to damage to the pump and / or to equipment supplied by the pumped fluid, potentially resulting in their destruction.

[0003] DE 10 2008 053318 A1 relates to a reversible gear pump with a pumping chamber in which an outer rotor is mounted centrally and an inner rotor eccentrically. Two bearing chambers are formed in the inner circumferential wall of the pumping chamber, providing support for the outer rotor and connecting to the fluid supply via feed lines. The feed lines are integrated into the housing of the gear pump. Further gear pumps or pumps with pockets in the outer circumferential surface of the outer gear, pockets in the outer circumferential surface of the outer gear and pockets in the inner circumferential surface of the pumping chamber, or pockets in the inner circumferential surface of the pumping chamber are known from DE 10 2007 055911 A1, DE 10 2011 100105 A1, and JP 2015 108306 A. Other rotary pumps of this type are known from JP h02 75783 A, JP 2000 303966 A, DE 10 2005 007082 A1, DE 196 26 153 A1 and JP 2014 173587 A.

[0004] US patent 5,340,293 A1, for example, discloses a rotary pump in which an inner rotor is rotatably mounted by a bushing and an outer rotor is received in a spacer. To reduce friction between the outer rotor and the spacer, the patent discloses a pocket which is connected to the outlet of the rotary pump via a channel and is actively pressurized with pressurized fluid. A similar pump is also disclosed in DE 10 2009 024 216 A1.

[0005] One objective of the invention is to provide a rotary pump that has fewer or no starting problems, for example during a cold start.

[0006] This problem is solved by the rotary pump with the features of claim 1. The dependent claims can advantageously further develop the rotary pump according to the invention.

[0007] The invention relates to a rotary pump comprising a housing with a pumping chamber having an inlet for a fluid on a suction side of the rotary pump and an outlet for the fluid on a pressure side of the rotary pump. The rotary pump further comprises an inner rotor arranged eccentrically in the pumping chamber and an outer rotor arranged centrally in the pumping chamber, forming pumping cells with the inner rotor. The outer rotor is slidably mounted with its outer circumferential wall against an inner circumferential wall of the pumping chamber and is preferably guided by the latter. The inner circumferential wall of the pumping chamber or the outer circumferential wall of the outer rotor has at least two pockets or support pockets, respectively.

[0008] In the pocket area, the outer circumferential wall of the outer rotor has no contact with the inner circumferential wall of the pumping chamber of the rotary pump. This means that in the pocket area, the outer circumferential wall of the outer rotor and the inner circumferential wall of the pumping chamber neither seal against each other nor is the outer rotor guided by the inner circumferential wall, particularly by the housing. The rotary pump can be, in particular, an internal gear pump or a pendulum vane pump. Preferably, the rotary pump is designed as a lubricating oil pump for a motor vehicle, especially for the lubrication and / or cooling of an internal combustion engine of the motor vehicle.

[0009] The pockets can be arranged on the inner circumferential wall of the conveying chamber, particularly the housing, or have a radial and axial extent dimensioned such that there is no direct connection between the pockets and the outlet. Preferably, there is no direct connection, such as a channel or groove, connecting the pockets to the outlet. The terms "axial" and "radial" refer in particular to the axis of rotation of the inner rotor and / or outer rotor, so that the term "axial" specifically denotes a direction that runs parallel or coaxial to the axis of rotation. Furthermore, the term "radial" specifically denotes a direction that runs perpendicular to the axis of rotation. A "radial extent" is to be understood in particular as an extent along or parallel to a radial direction.An "axial extension" should in particular be understood to mean an extension along or parallel to an axial direction.

[0010] The pockets are supplied with fluid from the conveying chamber solely through leakage. To control the fluid supply to the pockets from the conveying chamber, sealing gaps, for example an axial sealing gap between an end face of the outer rotor and an axial wall of the housing, and / or the dimensions of the pockets, for example their axial and / or radial extent, can be selected accordingly. Advantageously, the sealing gaps and / or the pockets are designed in such a way as to minimize leakage from the conveying chamber into the pockets.

[0011] The pockets extend only over a portion of the axial length of the outer rotor, with only one open end face. The pockets are shorter in the axial direction than the axial length of the outer rotor. In particular, the pockets may be open at an end face that faces a bottom or lid axially closing off the conveying chamber.

[0012] Preferably, the radial extent of the pockets is significantly smaller than the axial extent of the pockets. The radial extent is advantageously a maximum of 20% of the axial extent, particularly advantageously a maximum of 10% of the axial extent, and most advantageously a maximum of 5% of the axial extent. The radial extent of the pockets is advantageously a maximum of 3 millimeters, particularly advantageously a maximum of 1.5 millimeters, and most advantageously a maximum of 0.5 millimeters.

[0013] The pockets are supplied or filled with the fluid pumped by the rotary pump through leakage within the pumping chamber.

[0014] At least one of the pockets can be located in the area of ​​the outlet from the conveying chamber, in the area of ​​the inlet to the conveying chamber, in the area of ​​the sealing rib, or in the area of ​​the drive rib. The pockets can be located adjacent to the outlet, adjacent to the inlet, adjacent to the sealing rib, or adjacent to the drive rib, viewed radially. The pockets are preferably separated from the fluid inlet and outlet.

[0015] One of the pockets can extend circumferentially along the inner perimeter wall from the outlet to the inlet.

[0016] One of the pockets can extend in the circumferential direction of the outer circumferential wall of the outer rotor and the inner circumferential wall of the conveying chamber from the sealing rib to the drive rib.

[0017] The rotary pump has two, three, or more pockets. A first pocket is located in the inlet area of ​​the pumping chamber, and a second pocket is located in the outlet area of ​​the pumping chamber. The first and second pockets can be arranged, for example, opposite each other with respect to an axis of rotation of the outer rotor, or offset from each other circumferentially, either in or against a direction of rotation of the pump.

[0018] The two, three or more pockets can preferably be arranged evenly distributed around the inner circumference of the conveying space.

[0019] If the inner circumferential wall of the conveying chamber has two pockets, these pockets can be fluidically connected to each other. This connection can be formed in the inner circumferential wall of the conveying chamber and / or the outer circumferential wall of the outer rotor. The connection can be permanent or dependent on the rotational position of the outer rotor. With two, three, or more pockets, at least one of the pockets can differ from at least one of the other pockets, for example, in geometry, shape, and / or size.

[0020] The inner or outer rotor can be connected or coupled to a drive, such as an electric motor or a shaft driven by an internal combustion engine, which generates the drive energy for the rotary pump. Preferably, the rotor is connected to an electric motor. If the vehicle is powered by an internal combustion engine, the rotary pump can be driven by the electric motor, preferably independently of the internal combustion engine, for example, when the engine is stationary. The rotary pump advantageously incorporates the electric motor. The rotary pump is preferably designed as an electric rotary pump. The rotary pump is preferably designed as an auxiliary pump and / or an additional pump to support and / or at least partially replace a main or primary pump in a lubrication and / or coolant system of a vehicle.The term "intended" is to be understood in particular as specifically designed, constructed, executed, arranged and / or programmed.

[0021] The direction of rotation of the rotary pump can be switched, allowing for flexible use. Switching the direction of rotation changes the flow direction of the pumped medium; in other words, it is a reversible rotary pump.

[0022] The casing of a rotary pump, particularly for an internal gear pump or a pendulum vane pump, can include a pot-shaped part that forms an inner circumferential wall and a bottom of a pumping chamber of the rotary pump. The inner circumferential wall includes the pockets.

[0023] The invention will be explained in more detail below using figures.

[0024] The figures show, in detail: Figure 1: Conveying chamber with a pocket in the inner circumferential wall of the conveying chamber in a central area of ​​the outlet from the conveying chamber. Figure 2: Conveying chamber with a pocket in the inner circumferential wall of the conveying chamber in the area of ​​the inlet to the conveying chamber, with a connecting channel that connects the pocket to the inlet. Figure 3: Conveying chamber with an indicated inner and outer rotor and a pocket in the inner circumferential wall of the conveying chamber in the area of ​​the inlet to the conveying chamber and in the area of ​​the outlet from the conveying chamber, with a connecting channel that connects one of the pockets to the inlet, and another connecting channel that connects the other of the pockets to the outlet. Figure 4: Conveying chamber with a pocket in the inner circumferential wall of the conveying chamber in the area of ​​the sealing rib and the drive rib. Figure 5: Conveying chamber with a pocket in the inner circumferential wall of the conveying chamber in an area of ​​the outlet from the conveying chamber that is offset in or against a direction of rotation of the rotary pump.Figure 6: Conveying chamber with one pocket according to the invention in the inner circumferential wall of the conveying chamber in the area of ​​the inlet to the conveying chamber and the outlet from the conveying chamber. Figure 7: Conveying chamber with three pockets according to the invention in the inner circumferential wall of the conveying chamber in a top view and in a perspective view with inner rotor and outer rotor. Figure 8: Conveying chamber with a pocket in the inner circumferential wall of the conveying chamber in a central area of ​​the inlet to the conveying chamber. Figure 9: Conveying chamber with an indicated inner and outer rotor and one pocket in the inner circumferential wall of the conveying chamber in the area of ​​the sealing rib and the drive rib, and a connection in the area of ​​the drive rib that connects the pocket to a conveying cell of the rotary pump.Figure 10: Conveying chamber with indicated inner and outer rotors and a pocket each in the inner circumferential wall of the conveying chamber in the area of ​​the sealing rib and the drive rib, as well as a connection in the area of ​​the drive rib and a connection in the area of ​​the sealing rib.

[0025] The Figure 1 Figure 1 shows a top view into the pumping chamber 1 of a rotary pump, which is not within the scope of independent claim 1, but is useful for understanding. Part of the housing 2 of the rotary pump is visible, along with the bottom 3 of the pumping chamber 1.

[0026] An opening 4 is formed eccentrically in the base 3, through which, for example, a drive axle for the only in the Figure 3 , 7 , 9, 10 The inner rotor 9 shown can be guided into the interior of the conveying chamber 1.

[0027] Furthermore, the base 3 has an inlet 5 for fluid into the pumping chamber 1 and an outlet 6 for fluid out of the pumping chamber 1. This numbering applies to a rotary pump with a counterclockwise rotating internal rotor 9. If the direction of rotation is reversed, inlet 5 becomes outlet 6, and outlet 6 becomes inlet 5.

[0028] The housing 2 forms an inner circumferential surface 11 of the conveying chamber 1, which together with an outer circumferential surface 12 of the also only in the Figure 3 , 7 , 9, 10 The outer rotor 10 shown forms a sealing gap 16 over large parts of its circumference, so that the inner circumferential surface 11 forms a guide or sliding surface for the outer rotor 10.

[0029] In the inner circumferential surface 11, a pocket 7 is formed in the region of the outlet 6, extending radially outwards. Viewed circumferentially, the pocket 7 is located centrally to the outlet 6. In the region of the pocket 7, the outer circumferential surface 12 of the outer rotor 10 and the inner circumferential surface 11 of the conveying chamber 1 are significantly spaced apart, so that the outer rotor 10 is not guided by the inner circumferential surface 11 in the region of the pocket 7. Fluid from the outlet 6 and / or from at least one conveying cell 13 formed by the inner rotor 9 and outer rotor 10, in which the fluid is transported from the inlet 5 to the outlet 6 and can be compressed and / or raised to a higher pressure level, can enter the pocket 7, for example, via a leakage flow.

[0030] The fluid can be, for example, an oil pumped from a reservoir to a consumer. The fluid or oil collecting in pocket 7 can then be used when starting the rotary pump to ensure immediate lubrication in the sealing gap between the inner circumferential wall 11 and the outer circumferential surface 12 of the outer rotor 10, thus reducing the force required to start the rotary pump. The fluid collected in pocket 7 can also have a damping effect and contribute to smoother operation of the rotary pump, i.e., reduced noise during operation. Finally, the fluid in pocket 7 can prevent or at least delay wear on the outer circumferential surface 12 of the outer rotor 10 and the inner circumferential surface 11 of the pumping chamber 1, thereby increasing the service life of the rotary pump.

[0031] In the Figure 2The figure shows a rotary pump that is not within the scope of independent claim 1, but is useful for understanding. The pocket 7 is formed in the region of the inlet 5 and is connected to the inlet 5 via a connection 8 in the base 3. Fluid can flow from the inlet 5 through the connection 8 into the pocket 7 and fill the pocket 7 with the fluid to be pumped. The connection 8 is designed as a groove in the base 3 open to the pumping chamber 1.

[0032] The Figure 3 Figure 1 shows an embodiment of a rotary pump, which is not within the scope of independent claim 1, but is useful for understanding, in which two pockets 7 are formed in the inner circumferential surface 11 of the pumping chamber 1. Figure 3The inner rotor 9 and the outer rotor 10 are indicated. A pocket 7 is formed in the area of ​​the inlet 5 and the outlet 6, respectively. Each pocket 7 is connected to its associated inlet 5 and outlet 6 via a connection 8. The two connections 8 shown, or the pockets 7, can be fluidically connected to each other by a further connection (not shown), which may be formed, for example, in the inner circumferential wall 11 or in the base 3.

[0033] In the Figure 4 A pocket 7 is formed in the area of ​​the drive web 14 and the sealing web 15 in the inner circumferential wall 11. In the Figure 5 , which are essentially the Figure 1This corresponds to, and is therefore not within the scope of independent claim 1, but is useful for understanding, the single pocket 7, viewed circumferentially, is not centered or located centrally, but offset from the outlet 6. The pocket 7 of this embodiment can, in particular, be filled with overflowing material, only in the Figure 3 , 7 , 9, 10 The pumping cells 13 shown and / or a leakage flow are supplied and filled with fluid.

[0034] In the exemplary embodiment of the Figure 6 Does the arrangement of the pockets 7 in the inner circumferential surface 11 correspond to the arrangement as in the Figure 3 shown. Unlike in the Figure 3 The pockets 7 are not connected to the inlet 5 and outlet 6 respectively via a connection 8, but are supplied with fluid via a leakage flow and possibly overflowing pumping cells 13.

[0035] The Figure 7Figure 1 shows an embodiment of a rotary pump according to the invention, comprising three pockets 7 which are arranged in a substantially uniform manner around the circumference of the pumping chamber 1 and thus in the circumferential direction. The pockets 7 can all be identical, or each pocket 7 can have a different geometry, shape, and / or size than another pocket 7.

[0036] In a perspective view, the housing 2 with the conveying chamber 1 is shown. The outer rotor 10 is located in the conveying chamber 1, and an eccentrically mounted inner rotor 9 is arranged within the outer rotor 10. The inner rotor 9 and the outer rotor 10 together form conveying cells 13 in which the fluid can be transported from the inlet 5 to the outlet 6, whereby the pressure in the fluid is increased and / or the fluid is compressed during transport. The inner rotor 9 or the outer rotor 10 can be connected to a rotary drive, with the driven inner rotor 9 / outer rotor 10 transmitting the rotary motion to the undriven outer rotor 10 / inner rotor 9.

[0037] The exemplary embodiment of the Figure 8 essentially corresponds to that of the Figure 2 , and is therefore also not within the scope of independent claim 1, but is useful for understanding. In the Figure 8The pocket 7 is located centrally or midway in the circumferential direction within the area of ​​the inlet 5. The pocket 7 lacks a direct connection to the inlet 5 and the outlet 6. Alternatively, the rotary pump may have a connection that links the pocket 7, located within the area of ​​the inlet 5, to the outlet 6. This connection may be located in the base 3, the outer circumferential surface 12, and / or the inner circumferential surface 11.

[0038] In the Figure 9In a feature not covered by independent claim 1, but useful for understanding, a pocket 7 is arranged in the region of the sealing rib 15 and the drive rib 14. A connection 8 is formed in the drive rib 14, which connects the pocket 7 to the conveying cell 13 overflowing the connection 8, so that the residual fluid from this conveying cell 13, which may be under particularly high pressure (especially crush pressure), can flow into the pocket 7. This pressure relief at or in the drive rib 14 can be advantageous for the smooth running of the inner rotor 9, as it reduces forces perpendicular to the axis of rotation of the inner rotor 9.

[0039] In the Figure 10Which is not within the scope of independent claim 1, but is useful for understanding, a pocket 7 is arranged in the region of the sealing rib 15 and the drive rib 14. In the drive rib 14 and in the sealing rib 15, a connection 8 is formed in each case, which connects the respective pocket 7 to the conveying cell 13 overflowing the connection 8. Reference symbol list:

[0040] 1 Conveyor chamber 2 Housing 3 Base 4 Opening 5 Inlet 6 Outlet 7 Pocket 8 Connection 9 Inner rotor 10 Outer rotor 11 Inner perimeter wall 12 Outer perimeter wall 13 Conveyor cell 14 Drive link 15 Sealing link 16 Sealing gap

Claims

1. A rotary pump, comprising: (a) a housing (2) featuring a delivery space (1) which comprises an inlet (5) for a fluid on a suction side of the rotary pump and an outlet (6) for the fluid on a pressure side of the rotary pump; (b) an inner rotor (9) which is arranged eccentrically in the delivery space (1); and (c) an outer rotor (10) which is arranged centrically in the delivery space (1) and forms delivery cells (13) with the inner rotor (9), (d) wherein an outer circumferential wall (12) of the outer rotor (10) is mounted in a sliding manner on an inner circumferential wall (11) of the delivery space (1), (e) the inner circumferential wall (11) comprises at least a first pocket (7) in the region of the inlet (5) and a second pocket (7) in the region of the outlet (6), (f) and the pockets (7) extend over only some of the axial length of the delivery space (1) or the outer rotor (10), characterised in that (g) the pockets (7) comprise only one open end-facing side and (h) are separated from the inlet (5) and the outlet (6), and the pockets (7) are supplied with the fluid from the delivery space (1) only by leakage.

2. The rotary pump according to the preceding claim, comprising another, third pocket (7), wherein the at least three pockets (7) are arranged in a distribution over the inner circumference of the delivery space (1), and the third pocket (7) is also supplied with the fluid from the delivery space (1) only by leakage.

3. The rotary pump according to the preceding claim, wherein the third pocket (7) is arranged in the region of the sealing stay (15) or driving stay (14).

4. The rotary pump according to the preceding claim, wherein the additional pocket (7) extends from the outlet (6) up to the inlet (5) in the circumferential direction of the inner circumferential wall (11).

5. The rotary pump according to any one of the preceding claims, wherein the first pocket (7) and / or the second pocket (7) extend(s) from the sealing stay (15) up to the driving stay (14) in the circumferential direction of the inner circumferential wall (11).

6. The rotary pump according to any one of the preceding claims, wherein the inner circumferential wall (11) of the delivery space (1) and / or the outer circumferential wall (12) of the outer rotor (10) comprises at least two pockets (7) which are connected to each other via a connection (8).

7. The rotary pump according to any one of the preceding claims, comprising an electric drive.

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