Fluid pump

Abstract

Fluid pump (10) comprising: a housing (14) which has a pump chamber (16) and an electronics chamber (18); a fluid-pumping device (24) located in the pump chamber (16) of the housing (14); a main suction port (38) emerging into a fluid inlet (40) of the fluid-pumping device (24), and a main pressure port (42) in flow connection with a fluid outlet (44) of the fluid-pumping device (24); and an electric motor (26) which is located in the electronics chamber (18) of the housing (14) and has a stator (28) and a rotor (30) for driving the fluid-pumping device (24). A flow path extends from the main suction port (38), past the fluid-pumping device (24), to the electronics chamber (18). The rotor (30) of the electric motor (18) contains a stationary fluid-conducting element (51).

Description

[0001] Fluid pump

[0002] The invention relates to a fluid pump comprising a housing which has a pump chamber and an electronics chamber.

[0003] The pump housing contains a fluid-pumping device while the electronics chamber contains the electronic components, for example an electric motor for driving the fluid-pumping device and a printed circuit board. Generally, control electronics are present on the printed circuit board.

[0004] Such pumps are used for example in motor vehicles for pumping liquid media, such as oil or cooling water.

[0005] During operation of the fluid pump, the electric motor and the control electronics generate heat, and this has a negative effect on the efficiency of the electric motor.

[0006] It is known practice to discharge the heat generated by the electric motor and by the control electronics partly via the liquid transported by the fluid-pumping device. The known solutions, however, are unsatisfactory because the liquid to some extent does not reach the heat-generating components. Primarily in the regions of the electronics chamber that are remote from the pump chamber, no cooling effect or only an unsatisfactory cooling effect is obtained.

[0007] An object of the present invention is therefore to provide a heat pump with improved discharge of heat.

[0008] This object is achieved according to the invention by a fluid pump comprising: a housing which has a pump chamber and an electronics chamber; a fluid-pumping device located in the pump chamber of the housing; a main suction port emerging into a fluid inlet of the fluid-pumping device, and a main pressure port in flow connection with a fluid outlet of the fluid-pumping device; and an electric motor which is located in the electronics chamber of the housing and has a stator and a rotor for driving the fluid-pumping device. A flow path extends from the main suction port, past the fluid-pumping device, to the electronics chamber, wherein the rotor of the electric motor contains a stationary fluid-conducting element.

[0009] The fluid pump according to the invention has the advantage that the fluid pumped by the fluid pump is divided into two partial streams downstream of the main pressure port. One partial stream flows directly through the fluid-pumping device, and the further partial stream firstly flows past the fluid-pumping device into the electronics chamber, in order to cool the components in the electronics chamber.

[0010] The flow movement of the partial stream through the electronics chamber is established by fluid being drawn into a motor-side fluid inlet of the fluid-pumping device, this fluid inlet being in flow connection with the electronics chamber. The motor-side fluid inlet is located in particular on a side of the fluid-pumping device opposite the main suction port.

[0011] A centrifugal pump effect of the rotor, which also has a certain drawing-in effect owing to the build-up of fluid on the inner wall of the rotor, also has an assistive effect.

[0012] In addition, the fluid-conducting element in combination with the centrifugal pump effect of the rotor forces an axial movement of the fluid in the direction towards an electric-motor side remote from the fluid-pumping unit and thus assists the flow movement of the partial stream through the electronics chamber.

[0013] According to one embodiment, the electronics chamber axially adjoins the pump chamber, i.e. the electronics chamber and the pump chamber do not overlap.

[0014] According to one aspect, the rotor has at least one axially continuous cutout. Fluid flows through this cutout to a back side of the electric motor, as a result of which heat is discharged better, thereby contributing to effective cooling of the electric motor. As a result, the rotor surface contacted by media is especially large, and therefore an effective exchange of heat between the rotor and the fluid takes place. In this way, the efficiency of the electric motor can be improved and its service life extended.

[0015] According to one aspect, the fluid-pumping device in the pump chamber is at least partially enclosed around the circumference by a fluid chamber in flow connection with the main suction port, wherein the flow path extends through the fluid chamber from the main suction port to the electronics chamber. The fluid chamber is consequently located parallel to the fluid-pumping device in terms of flow connection. A fluid chamber at least partially enclosing the fluid-pumping device around the circumference makes it possible to obtain a sufficiently large flow cross section of the fluid chamber combined with a compact design.

[0016] A cooling duct for example extends from the fluid chamber to the electronics chamber and, radially on the inside of the rotor, emerges into the electronics chamber. The fluid present in the fluid chamber is consequently made to converge in the cooling duct and controlledly conducted into the internal chamber of the rotor.

[0017] For example, a return duct runs in the pump chamber from the electronics chamber to a motor-side fluid inlet of the fluid-pumping device. The pumped fluid can therefore flow through the intermediate spaces between the stator windings to a motor-side intake region of the fluid-pumping device and is pumped to the main pressure port by the fluid-pumping device. When the pumped fluid flows back into the fluid-pumping device, this also cools the stator of the electric motor.

[0018] A fluid inlet opening of the return duct can lie radially on the outside of the rotor at the transition between the electronics chamber and the pump chamber. This prevents a direct flow from the cooling duct to the return duct by circumventing the rotor, as a result of which it is ensured that all the electronic components can be effectively cooled.

[0019] The fluid-conducting element has, for example, the form of an impeller. If the fluid in the electronics chamber is made to spin by the rotor, the fluid flows along on the surfaces of the impeller in the axial direction.

[0020] According to one aspect, the fluid-conducting element has multiple helically extending directing surfaces, wherein the directing surfaces are spaced apart from one another in the circumferential direction. What this means is that the directing surfaces, i.e. the vanes, do not overlap in a plan view of the fluid conducting element, or in other words in an end-on view. The individual directing surfaces therefore do not run through a complete thread turn, but rather each only runs through a portion. Such an arrangement of the directing surfaces makes it possible to manufacture the fluid-conducting element particularly straightforwardly and cost- effectively. If the fluid-conducting element is manufactured as an injection-moulded part, it can be demoulded in a single demoulding direction.

[0021] For example, the housing has two parts and comprises an internal part and an external part enclosing the internal part around the circumference, wherein the fluid-conducting element is fastened to the internal part. For example, the fluidconducting element is pressed onto the internal part, plastics-welded thereto or fastened thereto in another way. It is also conceivable to produce the fluidconducting element in one piece with the internal part. The fluid-conducting element therefore does not need to be individually handled when the fluid pump is being mounted, thereby simplifying the mounting.

[0022] Manufacturing the housing in two parts makes it possible to produce a complex housing geometry that would not be possible with a one-piece manufacture.

[0023] An inner wall of the fluid chamber can be formed in the internal part of the housing and an outer wall of the fluid chamber can be formed in the external part. As a result, the fluid chamber is produced automatically when the housing parts are being mounted.

[0024] According to one aspect, for the purpose of driving the fluid pump, the rotor is torque-transmittingly coupled to a drive element of the fluid-pumping device via a drive shaft and a bearing sleeve for the drive shaft is formed in the internal part of the housing, wherein the fluid-conducting element is seated on the bearing sleeve. In this way, a compact design is achieved.

[0025] The fluid-pumping device may comprise an internal rotor located in the pump chamber of the housing, and an external rotor which surrounds the internal rotor, is rotatably mounted in the housing and, together with the internal rotor, forms a internal gear ring pump. The internal rotor is the drive element of the fluid-pumping device. Such a fluid-pumping unit is distinguished by a high delivery output and not requiring much space. In addition, an internal gear ring pump makes it possible to establish a uniform delivery flow with less pulsing. Furthermore, internal gear ring pumps are particularly resistant to wear and high pressures and have a long service life.

[0026] A screen element covering at least the main suction port may be located on an inlet side of the housing, i.e. on a side on which the main suction port is located. The screen element prevents relatively large particles that can cause wear of the fluid pump from being drawn in.

[0027] The screen element is for example a plastics injection-moulded part demoulded in one direction, as a result of which the screen element can be produced cost- effectively.

[0028] The electronics chamber may contain a printed circuit board on an electricmotor side remote from the pump chamber. Control electronics, for example, are integrated on the printed circuit board. Since the fluid to be pumped is guided along on the electric-motor side remote from the fluid-pumping unit, the printed circuit board is also sufficiently cooled.

[0029] For example, a temperature sensor is located on the printed circuit board. Since the pumped fluid flows through the electronics chamber, the temperature sensor on the printed circuit board can be used to determine the temperature of the fluid to be pumped. This also contributes to a compact design. The electronic contactconnection of the temperature sensor is particularly straightforward, because it is not necessary to cover a distance to the circuit board.

[0030] It is, however, also conceivable for the temperature sensor to be located at a large spacing from the printed circuit board, for example in the pump chamber, more specifically in the fluid chamber.

[0031] In one variant, the electronics chamber can be divided into a wet chamber and a dry chamber by an intermediate wall, wherein the electric motor is located in the wet chamber and the printed circuit board is located in the dry chamber. This makes it possible to do away with the costly protection of the printed circuit board against corrosion.

[0032] Further advantages and features of the invention can be found in the following description and in the accompanying drawings, to which reference is made. In the drawings:

[0033] Figure 1 shows a fluid pump according to the invention,

[0034] Figure 2 shows a longitudinal section of the fluid pump from Figure 1 ,

[0035] Figure 3 shows a further section through the fluid pump from Figure 1 , Figure 4 shows a cross section along the line A-A in Figure 3,

[0036] Figure 5 shows a rotor of the fluid pump from Figure 1 ,

[0037] Figure 6 shows an end-on view of the rotor from Figure 5,

[0038] Figure 7 shows a fluid-conducting element of the fluid pump from Figure 1 ,

[0039] Figure 8 shows a further view of the fluid-conducting element from Figure 7,

[0040] Figure 9 shows a screen element of the fluid pump from Figure 1 ,

[0041] Figure 10 shows a view of a detail in the region where the screen element is fastened to the fluid pump, and

[0042] Figure 11 shows a partial section of a further variant of the fluid pump according to the invention.

[0043] Figure 1 shows a fluid pump 10 for pumping fluids such as oil or cooling water in motor vehicles, for example for transmission cooling.

[0044] On a suction side of the fluid pump 10 there is a screen element 12, which is described in more detail below in connection with Figures 9 and 10.

[0045] The fluid pump 10 comprises a housing 14 which has a pump chamber 16 and an electronics chamber 18.

[0046] As Figure 2 shows, the housing 14 is manufactured in two parts and comprises an internal part 20 and an external part 22 surrounding the internal part 20 around the circumference.

[0047] On the side of the electronics chamber 18, the housing 14 is closed by a cover 23.

[0048] The pump chamber 16 of the housing 14 accommodates a fluid-pumping device 24.

[0049] The electronics chamber 18 contains an electric motor 26 which has a stator 28 and a rotor 30. The rotor 30 is shown separately in Figures 5 and 6, specifically in a side view and an end-on view. In addition, the electronics chamber 18 contains a printed circuit board 31 on which control electronics for actuating the fluid pump 10 are integrated.

[0050] In the exemplary embodiment, the printed circuit board 31 is fastened, for example screwed, to a cover 23.

[0051] A temperature sensor 33 is located on the printed circuit board 31.

[0052] The fluid-pumping device 24 comprises an internal rotor 32 and an external rotor 34 enclosing the internal rotor 32.

[0053] The external rotor 34 is rotatably mounted in the housing 14 and, together with the internal rotor 32, forms an internal gear ring pump. Specifically, the internal rotor 32 is coupled to the external rotor 34 via a toothing (not shown in the figures), so that the external rotor 34 is made to rotate by a rotation of the internal rotor 32.

[0054] The internal rotor 32 is eccentric in relation to the external rotor 34.

[0055] When the internal rotor 32 is rotating, firstly a space between the teeth of the internal rotor 32 and the external rotor 34 is enlarged, this resulting in a negative pressure which draws in fluid. As the internal rotor 32 continues to rotate, the space gets smaller again, as a result of which the trapped fluid is expelled.

[0056] To drive the internal rotor 32, the rotor 30 of the electric motor 26 is torque- transmittingly coupled to the internal rotor 32 via a drive shaft 36.

[0057] A bearing sleeve 37 for the drive shaft 36 is integrally formed in the internal part 20 of the housing 14.

[0058] The bearing sleeve 37 extends into the electronics chamber 18.

[0059] The fluid pump 10 has a main suction port 38 emerging into a fluid inlet 40 of the fluid-pumping device 24, and a main pressure port 42 (see Figure 3) in flow connection with a fluid outlet 44 of the fluid-pumping device 24.

[0060] The main pressure port 42 emerges radially outwards in the exemplary embodiment.

[0061] The screen element 12 covers the main suction port 38 and thus prevents relatively large particles being drawn into the fluid pump 10. For cooling purposes, a fluid flow is possible not only through the fluid-pumping device 24 but also through the electronics chamber 18 of the fluid pump 10. This causes heat to be discharged from the electric motor 26 and the printed circuit board 31 , this having a positive effect on the efficiency and the service life of the fluid pump.

[0062] In order to enable a fluid flow through the electronics chamber 18, more specifically as far as a side of the electric motor 26 remote from the fluid-pumping device 24, a fluid chamber 46 at least partially enclosing the fluid-pumping device 24 in the pump chamber 16 around the circumference, a cooling duct 48 and a return duct 50 are present.

[0063] The rotor 30 of the electric motor 26 contains a stationary fluid-conducting element 51. In the exemplary embodiment, the fluid-conducting element 51 is fastened to the housing 14, more specifically to the internal part 20. Specifically, the fluid-conducting element 51 is pressed onto the bearing sleeve 37.

[0064] In the exemplary embodiment, the fluid chamber 46 is an annular chamber, the annular chamber not necessarily needing to be circular. An elliptical ring or a polygonal ring is also conceivable.

[0065] The annular chamber is not imperatively closed around the circumference.

[0066] The fluid chamber 46 is produced when the external part 22 of the housing 14 is mounted on the internal part 20, since an inner wall 47 of the fluid chamber 46 is formed on the internal part 20 and an outer wall 49 of the fluid chamber is formed on the external part 22. The inner wall 47 is located radially on the inside of the outer wall 49.

[0067] Both the cooling duct 48 and the return duct 50 are formed in the internal part 20 of the housing 14.

[0068] The fluid chamber 46 is in flow connection with the main suction port 38.

[0069] The cooling duct 48 extends from the fluid chamber 46 to the electronics chamber 18. The cooling duct 48, radially on the inside of the rotor 30, emerges into the electronics chamber 18. As Figures 2 and 3 show, the cooling duct 48 runs obliquely from the fluid chamber 46 to the rotor 30.

[0070] The return duct 50 runs in the pump chamber 16 from the electronics chamber 18 to a motor-side fluid inlet 52 of the fluid-pumping device 24.

[0071] A fluid inlet opening 54 of the return duct 50 lies radially on the outside of the rotor 30 at the transition between the electronics chamber 18 and the pump chamber 16.

[0072] In order to allow flow to pass through the electronics chamber 18, the rotor 30 has multiple, in the exemplary embodiment four, cutouts 56 extending axially through the rotor 30 (see Figures 2 and 6). The fluid can therefore flow all the way through the rotor 30 in the axial direction.

[0073] A flow path of the fluid to be pumped is depicted in Figure 3 using arrows, the flow path of the fluid flowing from the main fluid port 38 directly to the main pressure port 42 through the fluid-pumping device 24 being depicted by solid arrows and the flow path of the fluid flowing through the electronics chamber 18 being depicted by dashed-line arrows. The main suction port 38 is not shown in the sectional view in Figure 3 but is located adjoining the region identified by the inlet arrow.

[0074] As Figure 3 shows, the fluid flow is divided into two partial streams at the main fluid port 38.

[0075] At the fluid inlet 40 of the fluid pumping device 24, the first partial stream is transported to the fluid outlet 44 via the fluid pumping device 24 and discharged via the main pressure port 42.

[0076] The second partial stream runs in the fluid chamber 46, where the fluid is firstly distributed around the circumference, before it flows via the cooling duct 48 into the rotor 30 and through it, more specifically through the cutouts 56 (not shown in Figure 3 owing to the rotor position shown), to a back side of the electric motor 26, i.e. to a side of the electric motor 26 remote from the fluid-pumping device 24.

[0077] On the back side of the electric motor 26, the fluid is made to swirl and thus distributed on the back side. Here, the temperature sensor 33 can be used to measure the temperature of the fluid.

[0078] Then, the fluid flows through the intermediate spaces between the stator windings 58 to the pump chamber 16 and there enters a motor-side intake region of the fluid-pumping device 24.

[0079] From there, the fluid is pumped to the main pressure port 42 via the fluidpumping device 24.

[0080] The second partial stream thus efficiently discharges heat from the electronics chamber 18.

[0081] The flow of the second partial stream is caused both by the suction effect at the motor-side fluid inlet 52 and by the centrifugal-pump effect of the rotor 30.

[0082] The fluid-conducting element 51 in combination with the centrifugal-pump effect of the rotor 30 brings about a flow with an axial directional component through the rotor 30.

[0083] Figure 4 shows a sectional illustration of the openings, directed towards the electronics chamber 18, of the cooling duct 48 and of the return duct 50.

[0084] It is clear from Figure 4 that the cooling duct 48 is delimited to a greater extent in the circumferential direction than the return duct 50 is.

[0085] More specifically, the return duct 50 is in flow connection with an opening 62 in the internal part 20 of the housing 14, this opening being located at the transition between the pump chamber 16 and the electronics chamber 18.

[0086] In the exemplary embodiment, the opening 62 extends around more than % of the circumference of the electric motor 26.

[0087] This causes the return duct 50 to be in flow connection with a multiplicity of intermediate spaces between the stator windings 58. This makes it possible to divide the second partial stream inside the stator 28 again into a multiplicity of parallel further partial streams.

[0088] In the return duct 50, these partial streams are made to converge again to form the second partial stream. Figures 7 and 8 show a separate view of the fluid-conducting element 51.

[0089] Figure 7 shows the impeller form of the fluid-conducting element 51.

[0090] The fluid-conducting element 51 has multiple helically extending directing surfaces 63.

[0091] The end-on view in Figure 8 shows that the directing surfaces 63 are spaced apart from one another in the circumferential direction. This makes it possible to manufacture the fluid-conducting element as a one-piece injection-moulded part which can be demoulded in one direction.

[0092] Figure 9 shows the screen element 12 in a plan view.

[0093] The screen element 12 has, distributed in the circumferential direction, multiple latching elements 64, in the exemplary embodiment shown four latching elements 64.

[0094] As Figure 10 shows, provided on the housing 14, more specifically on the external part 22 of the housing 14, is a radially protruding projection 66 to which a latching element 64 can be latched.

[0095] In the middle region, the screen element 12 has a multiplicity of cutouts 68, which form the screen structure.

[0096] In the exemplary embodiment, the screen element 12 is a one-piece injection- moulded part which can be demoulded in one direction, more specifically exclusively in the axial direction. To this end, the latching elements 64 are formed on flexible tabs 70, with the result that the screen element 12 can be removed from a mould without problems in spite of the undercuts in the region of the latching elements 64.

[0097] Figure 11 depicts a further variant of the fluid pump 10, with Figure 11 illustrating only one end of the electronics chamber 18.

[0098] One difference from the fluid pump 10 according to Figures 1 to 4 is that the electronics chamber 18 is divided into a wet chamber 76 and a dry chamber 78. A corresponding division is also conceivable in the embodiment according to Figures 1 to 4. The wet chamber 76 and the dry chamber 78 are delimited from one another by an intermediate wall 80.

[0099] The intermediate wall 80 is formed on an intermediate part 82 inserted between the external part 22 of the housing 14 and the cover 23. The printed circuit board 78 is located in the dry chamber 31 , while the electric motor 26 is located in the wet chamber 76.

[0100] If such an intermediate wall 80 is present, the cover 23 can in principle be omitted. In this case, the printed circuit board 31 is potted, for example with a resin, to protect against moisture and mechanical damage.

Claims

Claims1. Fluid pump (10) comprising: a housing (14) which has a pump chamber (16) and an electronics chamber (18); a fluid-pumping device (24) located in the pump chamber (16) of the housing (14); a main suction port (38) emerging into a fluid inlet (40) of the fluid-pumping device (24), and a main pressure port (42) in flow connection with a fluid outlet (44) of the fluid-pumping device (24); and an electric motor (26) which is located in the electronics chamber (18) of the housing (14) and has a stator (28) and a rotor (30) for driving the fluid-pumping device (24), wherein a flow path extends from the main suction port (38), past the fluid-pumping device (24), to the electronics chamber (18), and wherein the rotor (30) of the electric motor (18) contains a stationary fluidconducting element (51).

2. Fluid pump (10) according to Claim 1 , characterized in that the rotor (30) has at least one axially continuous cutout (56).

3. Fluid pump (10) according to either of the preceding claims, characterized in that the fluid-pumping device (24) in the pump chamber (16) is circumferentially at least partially surrounded by a fluid chamber (46) in flow connection with the main suction port (38), wherein the flow path extends through the fluid chamber (46) from the main suction port (38) to the electronics chamber (18).

4. Fluid pump (10) according to Claim 3, characterized in that a cooling duct (48) extends from the fluid chamber (46) to the electronics chamber (18) and emerges into the electronics chamber (18) radially on the inside of the rotor (30).

5. Fluid pump (10) according to Claim 4, characterized in that a return duct (50) runs in the pump chamber (16) from the electronics chamber (18) to a motorside fluid inlet (52) of the fluid-pumping device (24).

6. Fluid pump (10) according to any of the preceding claims, characterized in that the fluid-conducting element (51) has the form of an impeller.

7. Fluid pump (10) according to Claim 6, characterized in that the fluidconducting element (51) has multiple helically extending directing surfaces (63), wherein the directing surfaces (63) are circumferentially spaced apart from one another.

8. Fluid pump (10) according to one of the preceding claims, characterized in that the housing (14) has two parts and comprises an inner part (20) and an outer part (22) surrounding the inner part (20) around the circumference, wherein the fluid-conducting element (51) is fastened to the inner part (20).

9. Fluid pump (10) according to Claim 8, characterized in that, for the purpose of driving the fluid pump (10), the rotor (30) is torque-transmittingly coupled to a drive element of the fluid-pumping device (24) via a drive shaft (36) and a bearing sleeve (37) for the drive shaft (36) is formed in the inner part (20) of the housing (14), wherein the fluid-conducting element (51) is seated on the bearing sleeve (37).

10. Fluid pump (10) according to any of the preceding claims, characterized in that the fluid-pumping device (24) comprises an internal rotor (32) located in the pump chamber (16) of the housing (14) and an external rotor (34) which surrounds the internal rotor (32), is rotatably mounted in the housing (14) and, together with the internal rotor (32), forms an internal gear ring pump.

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