Pump

Abstract

The invention relates to a pump (1) having an electric motor (2), which has a rotor (3) and a stator (5) surrounding the rotor, which stator is injection-molded with a plastic housing (4) and has an end-side opening (6), having a circuit board (7), which closes the end-side opening (6) in a sealing manner and, together with the stator (5), defines an interior space (9) through which a cooling fluid can flow, the rotor (3) is arranged in the interior space. The key point of the invention is that an elastic seal (10) is arranged between the plastic housing (4) and the printed circuit board (7), and at least two fastening elements (11) are arranged on the end face of the plastic housing (4), which fastening elements are connected to fastening contours on the printed circuit board (7).

Description

Technical Field

[0001] The present invention relates to a pump having an electric motor having a rotor and a stator surrounding the rotor, the stator being injection molded with a plastic housing and having end-side openings. Background Technology

[0002] An electric motor configured as a pump is known from WO 2024 / 044 988 A1. The electric motor includes: a housing having a receiving cavity, wherein the housing has a first opening; a stator disposed in the receiving cavity; and a rotor disposed in the stator, wherein the rotor includes a first end section passing through the housing and for outputting torque outwardly. Cooling fluid can be guided to a circuit board through the first opening in the wall section of the first receiving cavity, thereby extending the service life of the circuit board.

[0003] An analogous electric pump for a cooling circuit of an internal combustion engine is known from EP 1 503 083 A1. This pump has an electric motor with a rotor and a stator surrounding the rotor. The stator has an end-side opening and a circuit board that fluid-dichtly closes the end-side opening and, together with the stator, defines an internal space through which cooling fluid can flow, in which the rotor is arranged. The stator is injection-molded into a plastic housing.

[0004] Pumps known from existing technology can achieve a design that eliminates the need for the previously required isolation tank for separating wet and dry areas, thus enabling a space-optimized and cost-effective structural approach compared to implementations with isolation tanks. However, a drawback is that this structure, particularly the non-flexible connection between the circuit board and the stator's plastic housing, can lead to leaks at this connection and / or within the plastic housing. These leaks can cause cooling fluid to reach electrical components (especially the electrical connection between the circuit board and the stator) due to capillary action, leading to malfunctions at these points, which should be avoided. Cooling fluid can also creep along the electrical connection, damaging areas that were originally fluid-sealed. Summary of the Invention

[0005] Therefore, the problem of the present invention is to provide an improved or at least alternative embodiment of this type of pump, by which the disadvantages known from the prior art can be overcome in particular.

[0006] This problem is solved according to the invention by the subject matter of independent claim 1. Advantageous embodiments are the subject matter of dependent claims.

[0007] This invention is based on the following general idea: the internal space of the fluid-cooled pump (where the pump rotor is located) does not have a separate isolation tank, but is defined and sealed solely by a stator with end-side openings and a circuit board connected to the stator via an elastic seal in a fluid-sealing manner, the circuit board closing the end-side openings. This embodiment saves on the isolation tank and achieves improved cooling of the circuit board and the electronic components arranged on it, which are in direct contact with the cooling fluid. Simultaneously, the elastic seal arranged between the plastic housing and the circuit board reliably prevents undesirable leakage of the cooling fluid (and particularly contact with electrical components). To ensure that the seal is both elastic and reliably fluid-sealing, the connection between the circuit board and the plastic housing of the stator is achieved by at least two fixing elements.

[0008] Here, the pump according to the invention has an electric motor having a rotor and a stator surrounding the rotor and injection-molded over (or covered) by a plastic housing, the stator having the aforementioned end-side opening. Here, the plastic housing is particularly securely and non-removably connected to the stator. A circuit board is also provided, which seals the end-side opening of the stator (or plastic housing) in a fluid-tight manner and, together with the stator (particularly the plastic housing of the stator), defines an internal space through which a cooling fluid can flow, in which the rotor is arranged. According to the invention, a resilient (particularly rubber-resilient) seal is now arranged between the plastic housing of the stator and the circuit board, and at least two fixing elements are arranged on the end side of the plastic housing of the stator, these fixing elements cooperating (or connecting) with fixing contours on the circuit board, thereby fixing the circuit board relative to the plastic housing. According to one embodiment, these fixing elements are connected to the plastic housing in a position-fixed manner. According to one embodiment, these fixing elements are integrally formed with the plastic housing. According to a particular embodiment, these fixing elements extend through the plastic housing to the circuit board, wherein, in particular, at least one fixing element is constructed as an electrical conductor that electrically contacts (and in particular solders) the stator to the circuit board. Thus, any electrical contact between the circuit board and the stator that may be necessary for pump operation can simultaneously be used to secure the circuit board relative to the stator (or the plastic housing). The plastic housing thus extends at least at the end-side opening of the stator, particularly providing a mating surface for the resilient seal. In particular, the plastic housing also extends along the rotor-facing side of the stator. Preferably, the seal is at least partially elastically compressed by the combined action of the fixing profile and the fixing element, while simultaneously providing a seal between the plastic housing and the circuit board. Preferably, the fixing element and the fixing profile are connected such that a force flow is established through the seal, the fixing profile of the circuit board, the fixing element, and the plastic housing, and the force of this force flow elastically compresses the seal. A reliable seal to the outside of the internal space can be achieved by the resilient seal. Simultaneously, the risk of microcracks forming in the connection area between the circuit board and the plastic housing of the stator, or within the plastic housing, that could lead to leakage of the internal space, can be at least reduced. The circuit board and stator can be reliably and permanently securely connected to each other by at least two fixing elements (e.g., arranged opposite each other or evenly distributed around the opening edge of the end-side opening), for which, for example, it is only necessary to position (or orient) the circuit board with its fixing profile so that they can be fixed to each other. When the circuit board with its fixing profile is placed on the fixing element, the circuit board presses against the seal arranged below it and (particularly subsequently) provides a connection between the fixing element and the fixing profile. Thus, with the pump according to the invention, the separate isolation tank that has existed until now can be avoided on the one hand, and a reliable seal of the internal space can be achieved on the other.

[0009] By directly defining the internal space with the circuit board, the board can directly contact the cooling fluid without an intermediate isolation tank, thereby achieving significantly improved cooling. Eliminating the isolation tank not only reduces component diversity and thus pump complexity, but also consequently lowers manufacturing, storage, logistics, and assembly costs. The pump is therefore more durable. Eliminating the separate isolation tank also simplifies the assembly sequence and allows for a more compact overall structure, as the mounting space previously required for the isolation tank is now available. Furthermore, the so-called gapfill, which previously established heat transfer contact between the isolation tank and the circuit board, can be eliminated.

[0010] Preferably, the resilient seal extends around the internal space in a substantially arbitrary (but particularly annular) orientation. In an advantageous improvement of the pump according to the invention, a sealing groove, particularly an annular groove, is arranged on the end side of the plastic housing of the stator to accommodate the resilient seal. This sealing groove (or annular groove) opens toward the circuit board, thereby allowing the seal (e.g., an O-ring seal or an X-ring seal) arranged in the groove to be easily and accurately positioned, and the sealing effect can be achieved simply by placing the circuit board. This sealing groove can be manufactured by a corresponding plastic injection mold when the stator is plastic-injected, thus requiring no additional working steps.

[0011] Suitablely, the resilient seal is constructed as a ring seal, particularly as an O-ring seal or an X-ring seal. O-ring seals are well-known and widely used, and therefore can be individually adapted, depending on the manufacturer, to, for example, cooling media located in an internal space. When the resilient seal is constructed as an X-ring seal, an advantage compared to an O-ring seal is the provision of two sealing lips, each with a sealing surface, thereby further improving the sealing effect.

[0012] In an advantageous improvement to the pump according to the invention, the resilient seal is constructed as a sealing lip, which is specifically injection-molded onto the plastic housing. This provides a significant advantage: the seal between the plastic housing of the stator (one side) and the circuit board (the other side) is achieved via the sealing lip on the plastic housing side, without the need to maintain and install a separate seal. Another significant advantage of the sealing lip injection-molded onto the opening edge of the plastic housing is that the seal can be manufactured together with the plastic housing during the injection molding process of the stator. It is conceivable that the sealing lip is made of a different plastic than the plastic housing of the stator, thus creating a 2K plastic injection-molded part in this case. Purely theoretically, it is also conceivable that a seal constructed as a ring seal or a seal constructed as a sealing lip could be provided to further improve the seal.

[0013] In a particularly preferred embodiment, these fixing elements are constructed as thermal contact riveting elements, wherein the circuit board has at least two through holes with a complementary construction to these thermal contact riveting elements, through which the thermal contact riveting elements pass. The circuit board and the stator can be reliably and permanently securely connected to each other by means of at least two thermal contact riveting elements, for which, for example, it is only necessary to position (or orient) the circuit board with its through holes such that the through holes and the thermal contact riveting elements on the plastic housing side are aligned with each other. When the circuit board is placed on the thermal contact riveting elements with its through holes, the circuit board presses against a seal disposed below it, and then the thermal contact riveting elements are thermoformed, forming rivet heads during the thermoforming process. These rivet heads, upon cooling, reliably secure the circuit board to the stator.

[0014] Alternatively, these retaining elements can be conceived as snap-fit ​​elements, wherein the circuit board has at least two snap-fit ​​profiles complementary to these snap-fit ​​elements, with the snap-fit ​​elements engaging with these snap-fit ​​profiles. Particularly preferably, these snap-fit ​​profiles are arranged radially outward from the circuit board. Thus, these snap-fit ​​profiles are formed by a portion of the outer contour of the circuit board. This provides the significant advantage that no through-holes need to be provided in the circuit board; instead, the circuit board can be snapped back at the edge by the snap-fit ​​elements. Furthermore, the position of these retaining elements can be offset outward to the maximum extent to optimize mounting space. In this way, a detachable, but fluid-tight, connection can also be established between the circuit board and the stator, thereby allowing access to the internal space (rotor space) by releasing the snap-fit ​​elements, which, for example, simplifies maintenance.

[0015] In another advantageous embodiment of the pump according to the invention, the circuit board has at least one sensor, particularly a temperature sensor and / or a Hall sensor.

[0016] Particularly preferably, the sensor is arranged on the side facing the interior space. This improves measurement accuracy. For example, if the temperature sensor is arranged on the side facing the interior space, the temperature of the cooling fluid can be detected relatively simply, accurately, and quickly, thereby enabling rapid and reliable control (or regulation) of the pump. It is generally desirable that all electronic components are preferably arranged on the side of the circuit board facing away from the interior space, and thus protected within it.

[0017] If the sensor is configured as a Hall sensor, the pump preferably has a magnet corresponding to the Hall sensor, which is connected to the rotor in a fixed position. Through the combined action of the Hall sensor and the magnet, the rotation and / or relative position of the rotor can be detected. Particularly preferably, the magnet is arranged on the shaft. Specifically, the magnet is connected to the rotor and / or shaft in a fixed position by at least sectionally injection molding overlay.

[0018] For the most accurate evaluation possible, it is meaningful to arrange the Hall sensor and the magnet at the smallest possible relative distance. According to the preferred embodiment, the Hall sensor and the magnet are therefore spaced a maximum of 4 mm apart, and more particularly a maximum of 3.5 mm apart.

[0019] Suitably, the circuit board has a coating on its side facing the interior space. This coating protects the circuit board from the cooling fluid and abrasive particles carried by it, ensuring improved mechanical and chemical resistance. The coating also reduces the formation of microcracks and the risk of cooling fluid entering / passing through the circuit board. This coating can be made of, for example, silicone or epoxy resin. If the cooling fluid is neither conductive nor abrasive, such as oil, this coating can be removed, resulting in improved cooling of the circuit board.

[0020] In a preferred embodiment, the resilient seal rests directly on the coating of the circuit board. By providing a coating in the area of ​​the seal, a sealing surface that is continuously closed within the area of ​​the seal is provided.

[0021] Of course, one can also imagine that the circuit board has no coating, but rather that the material from which the circuit board is made is, for example, a circuit board substrate made of (especially flame-retardant) epoxy resin glass fiber composite material (such as FR-4), which is sufficient to provide adequate fluid sealing and abrasion resistance.

[0022] In another advantageous embodiment of the pump according to the invention, a reinforcing structure, such as reinforcing ribs, is arranged on the plastic housing. This reinforcing structure can, for example, be formed in the form of a mesh structure on the plastic housing of the stator. Since the plastic housing is subjected to the pressure of the cooling fluid during pump operation, and especially pressure pulsations and stresses at the stationary components, this reinforcing structure can be used to strengthen the plastic housing, thereby enabling it to withstand higher mechanical loads. This reinforcing structure (especially the reinforcing ribs) can, for example, be constructed as a web. Here, this reinforcing structure can be integrally formed with the plastic housing.

[0023] In a particularly preferred embodiment of the pump according to the invention, the plastic housing completely covers the stator on the rotor-facing side, particularly with a thickness of a maximum of 4 mm (particularly a maximum of 1 mm, particularly a maximum of 0.5 mm) and / or at least 0.3 mm. This thinnest possible plastic layer allows for reliable encapsulation of the stator while minimizing the gap between the stator and rotor, thereby ensuring that the efficiency of the motor is unaffected or only slightly affected.

[0024] The pump can be constructed, for example, as an oil pump, especially in motor vehicles, where other implementations are also conceivable, such as as a coolant pump, and especially as a water pump.

[0025] Advantageously, the retaining element is arranged in a dry area outside the resilient seal. Therefore, the resilient seal is located radially inside the retaining element in a circular cross-section. This separates the retaining element from the cooling fluid.

[0026] Other important features and advantages of the invention can be derived from the dependent claims, the drawings, and the description of related drawings based on the drawings.

[0027] It should be understood that the features described above and those explained below can be used not only in their respective specified combinations, but also in other combinations or individually, without departing from the scope of the invention. The components of the superior unit mentioned above and below, such as devices, equipment, or components, these individually identified portions may form individual parts or components of that unit, or form an overall region or segment of that unit, even if they are shown differently in the drawings. Attached Figure Description

[0028] Preferred embodiments of the present invention are shown in the accompanying drawings and explained in detail in the following description, wherein the same reference numerals denote the same or similar or functionally identical parts.

[0029] These are illustrated schematically here: Figure 1 A cross-sectional view of the pump according to the present invention. Figure 2 : A perspective view of the pump stator. Detailed Implementation

[0030] according to Figure 1 The pump 1 according to the invention (which may be configured as an oil pump or a coolant pump, for example) has an electric motor 2, which has a rotor 3 and a stator 5 surrounding the rotor 3 and injection-molded over a plastic housing 4. The plastic-injection-molded stator 5 (or plastic housing 4) has an end-side opening 6, which, according to... Figure 1 The circuit board 7 is sealed off in a fluid-tight manner relative to the cooling fluid flowing in the internal space 9 (rotor space). Therefore, the circuit board 7, together with the plastic housing 4 (or its inner sleeve 8), defines the internal space 9 through which the cooling fluid can flow, and the rotor 3 is rotatably arranged in the internal space 9.

[0031] According to the present invention, an elastic seal 10 is arranged between the plastic housing 4 and the circuit board 7, and at least two fixing elements 11 are also arranged on the end side of the stator 5 (or its plastic housing 4), such as... Figure 2 As shown, these fixing elements 11 work together with the fixing contour portion on the circuit board 7.

[0032] In the current configuration, circuit board 7 has at least two through holes that are complementary to at least two fixing elements 11 configured as thermal contact riveting members 17, through which the thermal contact riveting members 17 pass in the installed pump 1. The at least two through holes in circuit board 7 are configured according to... Figure 1 Located outside the cutting plane, therefore not shown.

[0033] By directly defining the internal space 9 through the circuit board 7, direct cooling of the circuit board 7 is achieved, thereby eliminating the need for the isolation tank that has been arranged between the circuit board 7 and the internal space 9. This not only reduces component diversity but also, consequently, reduces storage and logistics costs as well as assembly costs. Since the isolation tank is no longer needed, installation space is freed up, allowing the pump 1 according to the invention to be constructed more compactly overall. Eliminating the previously required isolation tank also eliminates the need for the thermal paste (gap filler) connecting the isolation tank to the circuit board 7, thereby eliminating other components and saving cost and installation space.

[0034] Continue to observe Figure 1 and Figure 2 An annular groove 12 can be seen arranged on the end side of the stator 5 (or plastic housing 4) to accommodate the resilient seal 10. Figure 1 and Figure 2 In the case shown, the seal 10 is constructed as an O-ring seal, which is not only inexpensive but also can be manufactured with almost any design.

[0035] Unlike the seal 10, which is constructed as an O-ring seal, this seal can also be constructed as an X-ring seal, which has the great advantage of providing two sealing lips and thereby two sealing surfaces relative to both the circuit board 7 and the annular groove 12, thus achieving a further improved seal.

[0036] In order to determine the temperature of the cooling fluid present in the internal space 9, a temperature sensor 13 can be arranged on the side of the circuit board 7 facing the internal space 9 (see...). Figure 1 The temperature sensor 13 preferably represents the sole electronic component 14 arranged on the side of the circuit board 7 facing the interior space 9. All other electronic components 14 are arranged on the side of the circuit board 7 facing away from the interior space 9, and therefore do not come into contact with the cooling fluid flowing in the interior space 9 at all. This allows for reliable and accurate temperature measurement of the cooling fluid, while all other electronic components 14 can be protected on the side of the circuit board 7 unaffected by the cooling fluid. Alternatively or additionally, the sensor arranged in the interior space 9 or on the side of the circuit board 7 facing away from the interior space 9 can also be configured as a Hall sensor.

[0037] Typically, the goal here is to arrange all electronic components 14 (including temperature sensor 13) on the side of the circuit board 7 away from the internal space 9, thereby protecting the electronic components from direct contact with the cooling fluid.

[0038] To ensure the sealing and integrity of the circuit board 7, the circuit board 7 may have a coating, such as a resilient and cooling fluid-resistant protective varnish, on the side facing the internal space 9. By providing this coating, the circuit board 7 is initially protected from the cooling fluid and abrasive particles carried by it, thereby achieving improved mechanical and chemical resistance. This coating is typically advantageously made, for example, of silicone or epoxy resin. If the cooling fluid is neither conductive nor abrasive, such as oil, this coating can be removed, resulting in improved cooling of the circuit board 7.

[0039] This coating on circuit board 7 can usually be omitted, especially if the material of circuit board 7 is, for example, a circuit board substrate made of a flame-retardant epoxy fiberglass composite material (e.g., FR-4), which is sufficient to provide adequate fluid sealing.

[0040] The plastic housing 4 completely covers the stator 5 on the side facing the rotor 3, particularly with a thickness between 0.3 mm and 0.5 mm. The plastic housing 4 can therefore have a thickness of preferably about 0.5 mm on the side facing the rotor 3, thereby achieving (particularly complete) encapsulation of the stator 5 on the one hand, while on the other hand, the distance between the rotor 3 and the stator 5 is not unnecessarily increased, and thus the efficiency of the motor 2 is not unnecessarily reduced.

[0041] Compared to pumps known from the prior art and similar pumps, the pump 1 according to the invention enables the absence of a rigid connection, particularly at the transition between the circuit board 7 and the opening edge 15 of the opening 6 of the stator 5 (or plastic housing 4), and more precisely, the presence of a connection with at least limited elasticity, which significantly reduces the susceptibility to cracking. At least slight relative movement between the circuit board 7 and the seal 10 can be achieved while maintaining a sufficient seal, regardless of whether the seal is constructed as an O-ring seal, an X-ring seal, or a sealing lip injection-molded onto the opening edge 15 of the plastic housing 4, through the elastic seal 10.

[0042] Unlike the seal 10, which is constructed as a separate ring seal, this resilient seal 10 can also be constructed as a sealing lip injection-molded onto the opening edge 15 of the opening 6 of the plastic housing 4. In this case, the seal 10 is integrally formed with the plastic housing 4 and can therefore be manufactured together with the plastic housing 4. Here, it is certainly conceivable that different plastics can be used for the sealing lip and the plastic housing 4, such as a particularly elastic (especially rubber-elastic) plastic for the sealing lip, which can produce a high sealing effect. In this case, this involves what is known as a 2K plastic injection molded part. The advantage of this injection-molded sealing lip is that it eliminates the need to produce, store, and install separate O-ring seals or X-ring seals, thereby reducing not only manufacturing costs but also storage and logistics costs, and relatedly assembly costs.

[0043] List of reference numerals 1 pump 2 Electric motor 3 rotors 4. Plastic casing 5 stators 6 Openings 7 Circuit Boards 8 Inner surface 9. Interior Space 10. Seals 11. Fixing elements 12 Annular groove 13 Temperature Sensor 14 Electronic Components 15. Opening edge 16 Dry Area 17. Thermal contact riveting components.

Claims

1. A pump (1), The pump has an electric motor (2) having a rotor (3) and a stator (5) surrounding the rotor, the stator being injection molded with a plastic housing (4) and having end-side openings (6). The pump has a circuit board (7) that seals the end opening (6) in a fluid-tight manner and, together with the stator (5), defines an internal space (9) through which cooling fluid can flow, in which the rotor (3) is arranged. Its features are, An elastic seal (10) is arranged between the plastic housing (4) and the circuit board (7), and at least two fixing elements (11) are arranged on the end side of the plastic housing (4), the fixing elements being connected to the fixing contour portion on the circuit board (7).

2. The pump (1) according to claim 1. Its features are, An annular groove (12) is arranged on the end side of the plastic housing (4) to accommodate the elastic seal (10).

3. The pump (1) according to claim 1 or 2. Its features are, The resilient seal (10) is constructed as a ring seal, particularly as an O-ring seal or an X-ring seal.

4. The pump (1) according to claim 1 or 2. Its features are, The resilient seal (10) is constructed as a sealing lip, which is specifically injection molded onto the plastic housing (4).

5. The pump (1) according to any one of the preceding claims. Its features are, - The fixing element (11) is constructed as a thermal contact riveting member (17). - The circuit board (7) has at least two through holes with a complementary structure to the thermal contact riveting member (17), through which the thermal contact riveting member (17) passes. or - The fixing element (11) is constructed as a snap-fit ​​element. - The circuit board (7) has at least two latching profiles that are complementary to the latching element, and the latching element engages with the latching profiles.

6. The pump (1) according to any one of the preceding claims. Its features are, The circuit board (7) has sensors, particularly a temperature sensor (13) and / or a Hall sensor, on the side facing the interior space (9).

7. The pump (1) according to any one of the preceding claims. Its features are, A reinforcing structure is arranged on the plastic shell (4).

8. The pump (1) according to any one of the preceding claims. Its features are, The circuit board (7) has a coating on the side facing the interior space (9).

9. The pump (1) according to any one of the preceding claims. Its features are, The plastic housing (4) completely covers the stator (5) on the side facing the rotor (3), in particular with a maximum thickness of 1 mm.

10. The pump (1) according to any one of the preceding claims. Its features are, The pump (1) is constructed as an oil pump or a coolant pump, particularly a water pump.

11. The pump (1) according to any one of the preceding claims. Its features are, The fixing element (11) is arranged outside the elastic seal (10) in the dry area (16).

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