Fluid pump

Abstract

A fluid pump (10) is described, comprising a housing (14) with a pump chamber (16) and an electronics chamber (18), a fluid conveying device (24) arranged in the pump chamber (16) of the housing (14), a main suction port (38) opening into a fluid inlet (40) of the fluid conveying device (24), and a main pressure port (42) connected to a fluid outlet (44) of the fluid conveying device (24), and an electric motor (26) with a stator (28) and a rotor (30) for driving the fluid conveying device (24) arranged in the electronics chamber (18) of the housing (14). A flow path extends from the main suction port (38) past the fluid conveying device (24) to the electronics chamber (18). A stationary fluid guide element (51) is arranged inside the rotor (30) of the electric motor (18).

Description

[0001] The invention relates to a fluid pump with a housing that includes a pump compartment and an electronics compartment.

[0002] The pump housing contains a fluid pumping device, while the electronic components, such as an electric motor for driving the fluid pumping device and a circuit board, are located in the electronics compartment. The circuit board typically houses control electronics.

[0003] Such pumps are used, for example, in motor vehicles to pump liquid media such as oil or cooling water.

[0004] During operation of the fluid pump, the electric motor and the control electronics generate heat, which negatively affects the efficiency of the electric motor.

[0005] It is known to partially dissipate the heat generated by the electric motor and the control electronics via the fluid transported by the fluid pump. However, the known solutions are inadequate because the fluid does not always reach the heat-generating components. Particularly in the areas of the electronics compartment furthest from the pump compartment, no cooling effect or only an insufficient one is achieved.

[0006] It is therefore an object of the invention to provide a fluid pump with improved heat dissipation.

[0007] This problem is solved according to the invention by a fluid pump with a housing comprising a pump chamber and an electronics chamber, a fluid conveying device arranged in the pump chamber of the housing, a main suction port opening into a fluid inlet of the fluid conveying device, and a main pressure port connected to a fluid outlet of the fluid conveying device, as well as an electric motor with a stator and a rotor for driving the fluid conveying device arranged in the electronics chamber of the housing. A flow path extends from the main suction port past the fluid conveying device to the electronics chamber, with a stationary fluid guide element arranged inside the rotor of the electric motor.

[0008] The fluid pump according to the invention has the advantage that the fluid pumped by the fluid pump splits into two partial flows downstream of the main pressure connection. One partial flow flows directly through the fluid pumping device, the other partial flow initially flows past the fluid pumping device into the electronics compartment to cool the components in the electronics compartment.

[0009] The flow of the partial current through the electronics compartment is generated by drawing fluid in at a motor-side fluid inlet of the fluid supply unit, which is fluidically connected to the electronics compartment. The motor-side fluid inlet is located, in particular, on the side of the fluid supply unit opposite the main suction port.

[0010] Additionally, the rotor has a centrifugal pumping effect, which also has a certain suction effect due to fluid adhesion to the inner wall of the rotor.

[0011] In addition, the fluid guide element, in combination with the centrifugal pumping effect of the rotor, forces an axial movement of the fluid towards the side of the electric motor facing away from the fluid conveying unit, thus supporting the flow movement of the partial current through the electronics compartment.

[0012] According to one embodiment, the electronics compartment connects axially to the pump compartment, meaning that the electronics compartment and the pump compartment do not overlap.

[0013] According to one aspect, the rotor has at least one axially continuous recess. Fluid passes through this recess to the rear of the electric motor, thus improving heat dissipation and contributing to effective motor cooling. This results in a particularly large contact area of ​​the rotor, enabling efficient heat exchange between the rotor and the fluid. In this way, the efficiency of the electric motor can be improved and its service life extended.

[0014] According to one aspect, the fluid conveying device in the pump chamber is circumferentially surrounded, at least partially, by a fluid chamber that is fluidically connected to the main suction port, with the flow path extending from the main suction port to the electronics compartment through the fluid chamber. The fluid chamber is therefore fluidically parallel to the fluid conveying device. By surrounding the fluid conveying device circumferentially, at least partially, a sufficiently large flow cross-section of the fluid chamber can be achieved while maintaining a compact design.

[0015] Starting from the fluid chamber, a cooling channel extends to the electronics chamber and opens radially into the electronics chamber inside the rotor. The fluid present in the fluid chamber is thus collected in the cooling channel and guided in a controlled manner into the interior of the rotor.

[0016] For example, a return channel runs from the electronics compartment in the pump chamber to the motor-side fluid inlet of the fluid pumping unit. The pumped fluid can then flow through the spaces between the stator windings to a motor-side suction area of ​​the fluid pumping unit and is conveyed by the fluid pumping unit to the main pressure connection. As the pumped fluid flows back into the fluid pumping unit, the stator of the electric motor is also cooled.

[0017] A fluid inlet opening for the return channel can be located radially outside the rotor at the transition between the electronics compartment and the pump compartment. This prevents direct flow from the cooling channel to the return channel, bypassing the rotor and ensuring that all electronic components are effectively cooled.

[0018] The fluid guide element, for example, has the shape of a paddle wheel. When the fluid in the electronics compartment is set into a centrifugal motion by the rotor, the fluid flows along the surfaces of the paddle wheel in an axial direction.

[0019] According to one aspect, the fluid guide element has several helically extending guide surfaces, which are spaced apart from each other in the circumferential direction. This means that the guide surfaces, or wings, do not overlap when viewed from above, or in other words, from the end face of the fluid guide element. Consequently, the individual guide surfaces do not complete a full thread, but only a segment. This arrangement of the guide surfaces allows for particularly simple and cost-effective manufacturing of the fluid guide element. If the fluid guide element is manufactured as an injection-molded part, it can be demolded in a single direction.

[0020] For example, the housing is two-part, comprising an inner part and an outer part that surrounds the inner part, with the fluid guide element attached to the inner part. The fluid guide element can be pressed onto the inner part, plastic-welded to it, or attached in some other way. It is also conceivable to manufacture the fluid guide element as a single unit with the inner part. Consequently, the fluid guide element does not need to be handled separately during the assembly of the fluid pump, which simplifies the process.

[0021] The two-part manufacturing of the housing allows for a complex housing geometry that would not be possible with a one-piece manufacturing process.

[0022] The inner part of the housing can form an inner wall of the fluid chamber, and the outer part an outer wall of the fluid chamber. Thus, the fluid chamber is automatically created during the assembly of the housing parts.

[0023] According to one aspect, the rotor for driving the fluid pump is coupled to a drive element of the fluid conveying device via a drive shaft, transmitting torque. A bearing sleeve for the drive shaft is formed in the inner part of the housing, with the fluid guide element sitting on this bearing sleeve. This results in a compact design.

[0024] The fluid pumping unit can comprise an inner rotor located within the pump chamber of the housing and an outer rotor surrounding the inner rotor. The outer rotor is rotatably mounted within the housing and, together with the inner rotor, forms an internal gear pump. The inner rotor serves as the drive element for the fluid pumping unit. Such a fluid pumping unit is characterized by high flow rates in a compact design. Furthermore, an internal gear pump enables a smooth flow with minimal pulsation. Internal gear pumps are also particularly resistant to wear and high pressures and have a long service life.

[0025] A filter element can be arranged on one inlet side of the housing, that is, on the side where the main suction port is located, and this filter element must at least cover the main suction port. The filter element prevents larger particles from being drawn in, which could cause wear on the fluid pump.

[0026] The sieve element, for example, is a plastic injection molded part that is demolded in one direction, making the sieve element inexpensive to manufacture.

[0027] In the electronics compartment, a circuit board can be mounted on the side of the electric motor facing away from the pump compartment. Control electronics, for example, are integrated onto this circuit board. Because the fluid being pumped flows along the side of the electric motor facing away from the fluid pumping unit, the circuit board is also adequately cooled.

[0028] For example, a temperature sensor is mounted on the circuit board. Since the pumped fluid flows through the electronics compartment, the temperature of the fluid being pumped can be determined using the temperature sensor on the circuit board. This also contributes to a compact design. The electronic connection of the temperature sensor is also particularly simple, as no gap to the circuit board needs to be bridged.

[0029] However, it is also conceivable to position the temperature sensor at a large distance from the circuit board, for example in the pump compartment, more precisely in the fluid compartment.

[0030] In one version, the electronics compartment can be divided into a wet area and a dry area by an intermediate wall, with the electric motor located in the wet area and the circuit board in the dry area. This eliminates the need for complex corrosion protection of the circuit board.

[0031] Further advantages and features of the invention will become apparent from the following description and from the accompanying drawings, to which reference is made. The drawings show: - Fig. 1 a fluid pump according to the invention, - Fig. 2 a longitudinal section of the fluid pump Fig. 1, - Fig. 3. Make another cut through the fluid pump Fig. 1, - Fig. 4 a cross-section along line AA in Fig. 3, - Fig. 5 a rotor of the fluid pump Fig. 1, - Fig. 6 the rotor off Fig. 5 in a front view, - Fig. 7 a fluid guiding element of the fluid pump made of Fig. 1, - Fig. 8 the fluid guide element from Fig. 7 in another view, - Fig. 9 a filter element of the fluid pump made of Fig. 1, - Fig. 10 a detailed view in the area of ​​the attachment of the filter element to the fluid pump, and - Fig. 11 a partial section of another variant of the fluid pump according to the invention.

[0032] Fig. Figure 1 shows a fluid pump 10 for pumping fluids such as oil or coolant in motor vehicles, for example for gearbox cooling.

[0033] A filter element 12 is arranged on one suction side of the fluid pump 10, which is subsequently described in connection with the Fig. 9 and Fig. 10 will be described in more detail.

[0034] The fluid pump 10 comprises a housing 14 which has a pump compartment 16 and an electronics compartment 18.

[0035] As in Fig. As can be seen in Figure 2, the housing 14 is made in two parts and comprises an inner part 20 and an outer part 22 that surrounds the inner part 20.

[0036] The housing 14 is closed off by a cover 23 on the side of the electronics compartment 18.

[0037] A fluid conveying device 24 is housed in the pump chamber 16 of the housing 14.

[0038] In electronics room 18, an electric motor 26 with a stator 28 and a rotor 30 is arranged. The rotor 30 is in the Fig. 5 and Fig. 6 shown separately, in a side view and a front view.

[0039] In addition, a circuit board 31 is arranged in the electronics room 18, on which control electronics for controlling the fluid pump 10 are integrated.

[0040] In the exemplary embodiment, the circuit board 31 is attached to the cover 23, for example by screwing it on.

[0041] A temperature sensor 33 is arranged on the circuit board 31.

[0042] The fluid conveying device 24 comprises an inner rotor 32 and an outer rotor 34 surrounding the inner rotor 32.

[0043] The outer rotor 34 is rotatably mounted in the housing 14 and, together with the inner rotor 32, forms an internal gear pump. Specifically, the inner rotor 32 is coupled to the outer rotor 34 via a gear connection (not visible in the figures), so that the outer rotor 34 is set in rotation by a rotation of the inner rotor 32.

[0044] The inner rotor 32 is arranged eccentrically to the outer rotor 34.

[0045] As the inner rotor 32 rotates, the space between the teeth of the inner rotor 32 and the outer rotor 34 initially increases, creating a negative pressure that attracts fluid. With further rotation of the inner rotor 32, the space decreases again, causing the trapped fluid to be expelled.

[0046] To drive the inner rotor 32, the rotor 30 of the electric motor 26 is coupled to the inner rotor 32 via a drive shaft 36 to transmit torque.

[0047] In the inner part 20 of the housing 14, a bearing sleeve 37 for the drive shaft 36 is integrally formed.

[0048] The bearing sleeve 37 extends into the electronics room 18.

[0049] The fluid pump 10 has a main suction port 38, which leads into a fluid inlet 40 of the fluid conveying device 24, as well as a main pressure port 42 (see Fig. 3), which is fluid-connected to a fluid outlet 44 of the fluid conveying device 24.

[0050] In the exemplary embodiment, the main pressure port 42 opens radially outwards.

[0051] The sieve element 12 covers the main suction port 38 and thus prevents larger particles from being sucked into the fluid pump 10.

[0052] For cooling purposes, a fluid flow is possible not only through the fluid conveying device 24, but also through the electronics compartment 18 of the fluid pump 10. This dissipates heat from the electric motor 26 and the circuit board 31, which has a positive effect on the efficiency and service life of the fluid pump.

[0053] In order to enable a fluid flow through the electronics room 18, more precisely up to a side of the electric motor 26 facing away from the fluid conveying device 24, a fluid space 46 which surrounds the fluid conveying device 24 in the pump room 16 at least partially in the circumferential direction, a cooling channel 48 and a return channel 50 are provided.

[0054] A stationary fluid guide element 51 is arranged inside the rotor 30 of the electric motor 26. In the exemplary embodiment, the fluid guide element 51 is attached to the housing 14, more precisely to the inner part 20. Specifically, the fluid guide element 51 is pressed onto the bearing sleeve 37.

[0055] In the exemplary embodiment, the fluid chamber 46 is an annular chamber, although the annular chamber does not necessarily have to be circular. An elliptical ring or a polygonal ring is also conceivable.

[0056] The annular space is not necessarily completely closed.

[0057] The fluid chamber 46 is formed when the outer part 22 of the housing 14 is mounted on the inner part 20, since an inner wall 47 of the fluid chamber 46 is formed on the inner part 20 and an outer wall 49 of the fluid chamber is formed on the outer part 22. The inner wall 47 is arranged radially inside the outer wall 49.

[0058] Both the cooling channel 48 and the return channel 50 are formed in the inner part 20 of the housing 14.

[0059] The fluid chamber 46 is flow-connected to the main suction port 38.

[0060] Starting from the fluid chamber 46, the cooling channel 48 extends to the electronics chamber 18.

[0061] The cooling channel 48 opens radially inside the rotor 30 into the electronics compartment 18. As in the Fig. 2 and Fig. As can be seen in Figure 3, the cooling channel 48 runs diagonally from the fluid chamber 46 to the rotor 30.

[0062] The return channel 50 runs in the pump room 16 from the electronics room 18 to a motor-side fluid inlet 52 of the fluid conveying device 24.

[0063] A fluid inlet opening 54 of the return channel 50 is located radially outside the rotor 30 at the transition from the electronics compartment 18 to the pump compartment 16.

[0064] To allow airflow through the electronics compartment 18, the rotor 30 has several, in the exemplary embodiment four, recesses 56 which extend axially through the rotor 30 (see Fig. 2 and Fig. 6) The fluid can therefore flow completely through the rotor 30 in the axial direction.

[0065] A flow path of the fluid to be pumped is in Fig. 3 is illustrated by arrows, with solid arrows illustrating the flow path of the fluid flowing from the main fluid port 38 through the fluid conveying device 24 directly to the main pressure port 42, and dashed arrows illustrating the flow path of the fluid flowing through the electronics compartment 18. The main suction port 38 is shown in the sectional view in Fig. 3 is not visible, but it is adjacent to the area marked by the entrance arrow.

[0066] As in Fig. As can be seen in Figure 3, the fluid flow splits into two partial flows at the main fluid connection 38.

[0067] The first partial flow is conveyed at the fluid inlet 40 of the fluid conveying device 24, via the fluid conveying device 24 to the fluid outlet 44 and discharged via the main pressure connection 42.

[0068] The second partial flow runs into the fluid chamber 46, where the fluid initially spreads circumferentially before flowing via the cooling channel 48 into the rotor 30 and through it, more precisely through the in Fig. 3 through recesses 56, which are not visible due to the rotor position shown, to a rear side of the electric motor 26, i.e. to a side of the electric motor 26 facing away from the fluid conveying device 24.

[0069] At the rear of the electric motor 26, the fluid is swirled and thus distributed on the rear.

[0070] The temperature of the fluid can be measured using the temperature sensor 33.

[0071] The fluid then flows through the spaces between the stator windings 58 to the pump chamber 16 and enters a motor-side suction area of ​​the fluid conveying device 24.

[0072] From there, the fluid is conveyed via the fluid conveying device 24 to the main pressure connection 42.

[0073] The second partial flow thus ensures efficient heat removal from electronics room 18.

[0074] The flow of the second partial flow is caused on the one hand by the suction effect at the motor-side fluid inlet 52 and on the other hand by the centrifugal pumping effect of the rotor 30.

[0075] The fluid guiding element 51, in combination with the centrifugal pumping action of the rotor 30, causes a flow with an axial directional component through the rotor 30.

[0076] Fig. Figure 4 shows in a cross-sectional view the openings of the cooling channel 48 and the return channel 50 that are directed towards the electronics room 18.

[0077] Out of Fig. Figure 4 shows that the cooling channel 48 is more restricted in the circumferential direction than the return channel 50.

[0078] More precisely, the return channel 50 is flow-connected to an opening 62 in the inner part 20 of the housing 14, which is located at the transition from the pump chamber 16 to the electronics chamber 18.

[0079] In the exemplary embodiment, the opening 62 extends over more than ¾ of the circumference of the electric motor 26.

[0080] This means that the return channel 50 is connected to a multitude of spaces between the stator windings 58. This allows the second partial current within the stator 28 to further divide into a multitude of parallel partial currents.

[0081] In the return channel 50, these partial flows are combined again to form the second partial flow.

[0082] The Fig. 7 and Fig. Figure 8 shows the fluid guide element 51 in a separate view.

[0083] Out of Fig. Figure 7 shows the impeller shape of the fluid guide element 51.

[0084] The fluid guiding element 51 has several helically extending guide surfaces 63.

[0085] In the front view in Fig. Figure 8 shows that the guide surfaces 63 are spaced apart from each other in the circumferential direction. This enables the fluid guide element to be manufactured as a one-piece injection-molded part that can be demolded in one direction.

[0086] Fig. Figure 9 shows the sieve element 12 in a top view.

[0087] The sieve element 12 has several locking elements 64 distributed in the circumferential direction, in the illustrated embodiment four locking elements 64.

[0088] As in Fig. As can be seen in Figure 10, a radially projecting projection 66 is provided on the housing 14, more precisely on the outer part 22 of the housing 14, on which a locking element 64 can engage.

[0089] In the middle area, the sieve element 12 has a large number of recesses 68 which form the sieve structure.

[0090] In the exemplary embodiment, the sieve element 12 is a one-piece injection-molded part that is demolded in one direction, more precisely exclusively in the axial direction. For this purpose, the locking elements 64 are formed on flexible tabs 70, so that the sieve element 12 can be easily removed from a mold despite the undercuts in the area of ​​the locking elements 64.

[0091] In Fig. Figure 11 illustrates another variant of the fluid pump 10, where in Fig. Figure 11 merely shows one end of the electronics room 18.

[0092] One difference compared to the fluid pump 10 according to the Fig. Paragraphs 1 to 4 consist of the electronics compartment 18 being divided into a wet compartment 76 and a dry compartment 78. A corresponding division is also present in the embodiment according to the Fig. 1 to 4 are possible.

[0093] The wet room 76 and the dry room 78 are separated from each other by an intermediate wall 80.

[0094] The intermediate wall 80 is formed on an intermediate part 82, which is inserted between the outer part 22 of the housing 14 and the cover 23.

[0095] The circuit board 31 is located in the dry room 78, while the electric motor 26 is located in the wet room 76.

[0096] If such an intermediate wall 80 is present, the cover 23 can generally be omitted. In this case, the circuit board 31 is potted, for example with a resin, to protect it from moisture and mechanical damage.

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