Pump device for motor vehicle

Abstract

The invention relates to a pump device (1) for conveying a cooling fluid W. The pump device (1) comprises a housing (2) in which a fluid channel (3) is arranged, through which a cooling fluid W to be conveyed can flow, and a drive unit (4) for driving the cooling fluid W conducted through the fluid channel (3). Furthermore, the pump device (1) comprises an electric sensor unit (5), which comprises at least one sensor (6), in particular a temperature sensor, for determining at least one measured variable characterizing the cooling fluid. The sensor unit (5) can be arranged at least partially in the fluid channel (3). The sensor (6) can be arranged outside the fluid channel (3) as a temperature sensor and is coupled to the fluid channel in a thermally conductive manner.

Description

Technical Field

[0001] The present invention relates to a pump device for a motor vehicle or for a cooling device of a motor vehicle, in particular a cooling device of a fuel cell system, and for conveying a cooling fluid, in particular oil, water or cooling water or the like, and in particular an oil pump, a water pump or the like. In addition, the present invention relates to such a motor vehicle, such a cooling device and a motor vehicle having such a cooling device and / or having a fuel cell system. Pump devices of this type can be implemented in different types, for example as a rotary pump, a cycloidal rotor pump, a rotary slide valve pump or the like. Finally, the present invention also relates to a method for determining a measured variable, in particular the fluid temperature, which characterizes a cooling fluid in a pump device according to the present invention. Background Art

[0002] The cooling fluid can be used to cool components of a motor vehicle that generate waste heat, such as a drive train of the motor vehicle, in particular a fuel cell system, by absorbing and carrying away the generated waste heat. Similarly, the cooling fluid can also be used to cool electrical or electronic components of a motor vehicle that generate waste heat.

[0003] In both cases, the cooling fluid typically circulates in a cooling circuit. Typically, a pump device is used to drive or convey the cooling fluid in the cooling circuit. In order to ensure proper function, it is important to know different parameters or measured variables as accurately as possible, such as the fluid temperature of the conveyed cooling fluid, the fluid pressure of the conveyed cooling fluid and thus the delivery power of the pump device and / or the electrical conductivity of the cooling fluid. For this purpose, suitable sensors can be arranged in the cooling circuit.

[0004] Such sensors are usually arranged along the cooling circuit in contact with the cooling circuit. For example, DE 10 2009 005 154 A1 discloses a pump device with different sensors for detecting measured variables. DE 1983928 U discloses a pump device having a temperature sensor arranged in the cooling fluid in the pump device.

[0005] However, the electrical implementation of the sensors in the cooling circuit, in particular the electrical wiring of the sensors for control and electrical energy supply, has proven to be very expensive and therefore cost-intensive. Furthermore, it has proven to be complex to ensure reliable detection of the corresponding measured variables on the one hand and to protect the electrical components from the influence of the cooling fluid on the other hand.

[0006] US2015 / 093253 A1 discloses a pump device for a fresh water module system and a method for detecting the fluid temperature of a medium transported by the pump device when measuring thermal radiation with the help of a temperature sensor. Based on the detected thermal radiation, the fluid temperature of the transported medium is determined with the help of a calculation performed externally. This method requires that the temperature sensor be arranged outside the cooling fluid. However, this method and the arrangement required for this are also time-consuming and may not be suitable for automotive applications because special conditions in terms of accuracy, robustness and reliability are applicable to automotive applications. Generally, it is necessary to quickly and reliably determine the fluid temperature of the cooling fluid. For example, it may be necessary to determine a change of 50K in the fluid temperature of the cooling fluid within a maximum of 30 seconds, in particular a maximum of 15 seconds, in particular a maximum of 7 seconds. Summary of the invention

[0007] The object of the present invention is therefore to provide an improved embodiment for the known pump device in which at least one of the disadvantages mentioned is partially or even completely eliminated. In particular, the object of the present invention is to provide a pump device which is compact and robust and which at the same time enables reliable detection of at least one of the measured variables of the cooling fluid, in particular the fluid temperature.

[0008] This object is achieved by the subject matter of the independent claims. Preferred embodiments are the subject matter of the dependent claims.

[0009] Therefore, the basic idea of ​​the present invention is to equip a pump device for a motor vehicle with a sensor unit, which can be arranged in a cooling circuit for circulating a cooling fluid, and the sensor unit has at least one sensor, especially at least two sensors, for determining one or more measured variables characterizing the cooling fluid, especially for determining two measured variables characterizing the cooling circuit. Since it is necessary to guide the cooling fluid to be circulated in the cooling circuit through a fluid channel arranged in the pump device for conveying the cooling fluid, it is recommended to integrate the sensor unit directly into the pump device. In this way, structural space can be saved. In addition, it is possible to use an electrical component that has already been installed in the pump device for this purpose for the electrical control or electrical energy supply of the sensor unit, the electrical component is, for example, a circuit board or a circuit board assembly (PCBA) with electrical / electronic components arranged thereon. In this way, a voltage supply device for supplying electrical energy to an electric drive unit and / or other electrical / electronic components, especially a control / regulator, of the pump device can be used at the same time to supply electrical energy to the sensor unit. In addition, a control / regulator for controlling the electric drive unit can be used at the same time to control the sensor unit and / or for processing the corresponding measured variables detected by the sensor unit. This enables a significant simplification of the construction of the pump device. This results in significant cost advantages. In principle, the pump device according to the invention can also be suitable for applications where the subject matter is not or at least not primarily the cooling of components that generate waste heat. Therefore, a cooling fluid can also be generally understood as a fluid or liquid.

[0010] Specifically, the pump device according to the invention for conveying a cooling fluid, in particular water, oil, cooling water or the like, comprises a housing in which a fluid channel is arranged, through which the cooling fluid to be conveyed can flow. For example, the fluid channel can be implemented as a water channel for water or cooling water as a cooling fluid or as an oil channel for oil as a cooling fluid. In addition, the pump device comprises a drive unit for driving the cooling fluid guided through the fluid channel.

[0011] Furthermore, the pump device comprises an electrical sensor unit which comprises at least one sensor for determining at least one measured variable, in particular a thermodynamic measured variable, which is characteristic of the cooling fluid, for example the temperature of the fluid.

[0012] According to a first aspect of the invention, the sensor unit is at least partially arranged in the fluid channel. In an advantageous embodiment, the sensor unit with at least one sensor projects into the fluid channel. This enables rapid and relatively direct detection of changes in characteristic properties of the cooling fluid.

[0013] According to a second aspect of the present invention, alternatively or in addition to the arrangement according to the first aspect of the present invention, at least one sensor of the sensor unit is arranged outside the fluid channel. The sensor is coupled to the fluid channel in a heat-conducting manner. In particular, the sensor is coupled to the fluid channel wall of the fluid channel in a heat-conducting manner. The fluid channel wall limits the space of the fluid channel that can be flowed through by the cooling fluid in the region of the sensor. Generally speaking, preferably, at least one sensor is implemented as a temperature sensor. Thus, the sensor can be used to determine the fluid temperature of the cooling fluid guided through the fluid channel. When the temperature sensor is coupled to the fluid channel in a heat-conducting manner, the temperature sensor is heated by heat-conducting coupling according to the fluid temperature for this purpose. The fluid channel wall can be made of metal, especially mainly made of metal. The fluid channel wall can contain metal and / or metal oxides such as zinc oxide, silicon carbide or the like. Preferably, the fluid channel wall is made of stainless steel. Preferably, the fluid channel wall is non-magnetic or has only paramagnetic properties or antimagnetic properties. Preferably, the fluid channel wall is made of stainless steel. In some embodiments, the fluid channel wall can be made of plastic with fillers to ensure good thermal conductivity. For example, metals / metal oxides or the aforementioned materials come into consideration as fillers. Since metal-containing materials have good thermal conductivity, the heat transfer from the cooling fluid to the fluid channel wall and from the fluid channel wall to the temperature sensor can be improved.

[0014] Compared to other types of heat transfer, such as thermal radiation or convection, this coupling by heat conduction has proven to be particularly effective in order to ensure a rapid and accurate determination of the fluid temperature while configuring the pump device robustly. In addition to heat conduction, other heat transfer mechanisms can contribute slightly to the heat transfer between the cooling fluid and the temperature sensor. However, this is negligible for the heat transfer from the fluid channel wall to the temperature sensor.

[0015] In a preferred embodiment, the sensor and the fluid channel wall of the fluid channel are spaced apart from each other by less than 10 mm, in particular less than 5 mm, in particular less than 3 mm, in particular less than 0.5 mm, in particular less than 0.35 mm. If the sensor is arranged as close as possible to the fluid channel, good heat conduction is ensured.

[0016] Preferably, the entire sensor unit is arranged in the housing of the pump device outside the fluid channel, whereby the sensor unit is better protected.

[0017] According to an advantageous embodiment, the fluid channel wall has an outer recess in which the sensor, in particular the sensor unit, is at least partially arranged. Preferably, at least 50%, in particular at least 70%, in particular completely, of the sensor unit is embedded in the recess. In particular, the depth of the recess is at least 2 mm, in particular 3 mm to 5 mm, in particular a maximum of 7 mm, in particular a maximum of 4 mm. The outer recess can be implemented as a pressed portion of the fluid channel wall in the direction of the inner side of the fluid channel wall, in particular in a deep-drawn manner. Particularly preferably, in order to improve heat conduction, the sensor or the sensor unit is pressed against the fluid channel wall in the recess. With the aid of the recess, the fluid channel wall can have a corresponding inner protrusion. The inner side of the fluid channel wall is the side of the fluid channel wall that delimits the space of the fluid channel through which the cooling fluid can flow. Generally speaking, it is preferred that the fluid channel wall is implemented in one piece, in particular as a sheet metal component or an injection molded part.

[0018] By means of the best possible thermal coupling of the sensor to the fluid channel or to the fluid channel wall of the fluid channel, the sensor can be arranged outside the fluid channel and still be able to determine the fluid temperature well. The arrangement outside the fluid channel in the housing of the pump device not only enables better protection of the sensor means but also enables simpler attachment to other electrical / electronic components of the pump device, such as a control / regulatory device.

[0019] The invention also includes advantageous embodiments in which the sensor unit as a whole has the features mentioned above for the sensor or temperature sensor with regard to its arrangement relative to the fluid channel or its interaction with the fluid channel.

[0020] The thermally conductive coupling can be improved by connecting the sensor and the fluid channel, in particular the fluid channel wall, in a thermally conductive manner via a thermally conductive layer, in particular a thermally conductive paste and / or a gap filler and / or a thermally conductive pad.

[0021] Preferably, the fluid channel has two channel areas, which are arranged in sequence in the fluid channel along the flow path of the cooling fluid. The flow path describes the distance that the fluid micro-part of the cooling fluid passing through the fluid channel passes through the position closest to the sensor unit in the fluid channel. One channel area in the channel area is implemented to guide the cooling fluid in the direction toward the sensor unit, and the other channel area in the channel area is implemented to guide the cooling fluid guided in the direction toward the sensor unit away from the sensor unit. In this way, when the pump device is running, the cooling fluid is transported through the two channel areas in sequence. Generally speaking, it is preferred that the fluid channel area is oriented so that the cooling fluid from one channel area in the channel area flows to the fluid channel wall before entering the other channel area. Preferably, the fluid channel wall is configured to divert the cooling fluid from one channel area in the channel area to the inlet in the other channel area in the channel area, which improves the oncoming flow. Particularly preferably, the fluid channel is designed to deflect the cooling fluid along the flow path at the height of the sensor unit or at least one sensor, in particular by at least 30°, in particular by at least 90°, in particular by at least 120°, in particular by at least 160° relative to the corresponding orientation of the flow path directly before and after the deflection, which produces favorable incident flow conditions for heat transfer in the deflection area when the pump device is moved. Preferably, therefore, the fluid channel predetermines a flow path for the cooling fluid from one of the channel areas to the fluid channel wall and from the fluid channel wall through another channel area in the channel area. The preferably continuous incident flow improves the heat transfer from the cooling fluid to the fluid channel or the fluid channel wall, so that changes in the fluid temperature of the cooling fluid can be well detected.

[0022] In a preferred embodiment of the pump device according to the present invention, the drive unit of the pump device includes a rotatable drive shaft, on which the pump rotor is arranged in a rotationally fixed manner for conveying cooling fluid in the fluid channel. Depending on the type of pump, the pump rotor can be implemented, for example, as an impeller, a gear, a cycloidal rotor, an eccentric wheel or an eccentric worm, a rotary slide valve or the like. In addition, the pump device includes an electric motor having a stator and a rotor for driving the drive shaft. Here, the stator is arranged in a fixed position relative to the housing, and the rotor is connected to the drive shaft in a rotationally fixed manner so that relative rotational movement can occur between the rotor and the stator. Preferably, the rotor is implemented in a permanent magnetic manner. The drive shaft can be arranged in a rotatable manner on the housing of the pump device or on another component arranged in a fixed position relative to the housing by means of a suitable bearing element.

[0023] According to a generally preferred embodiment, the pump device has a wet region and a dry region which is sealed in a fluid-tight manner relative to the wet region. This prevents liquid, in particular cooling fluid, from entering the dry region from the wet region. The rotor of the motor is arranged in the wet region and the stator of the motor is arranged in the dry region. Such so-called wet rotors are known to those skilled in the art. The fluid channel extends in the wet region of the pump device. Other components required for conveying the cooling fluid can be arranged in the wet region respectively. A temperature sensor arranged outside the fluid channel and coupled to the fluid channel in a heat-conducting manner is arranged in the dry region.

[0024] Preferably, the pump device has a gap pot which separates the dry area and the wet area in a fluid-tight manner. Preferably, the fluid channel wall is formed at least in sections by the gap pot. The gap pot is especially made of metal, wherein non-magnetic materials should preferably be used in order to avoid adverse interactions with permanent magnetic components and / or electromagnetic components.

[0025] In general, preferably, the fluid channel extends in sections in the axial direction in the region between the stator and the rotor in radial direction, respectively with respect to the rotation axis of the rotor. In particular, the drive shaft and / or the rotor of the electric machine each delimit at least one channel region. As a result, the pump device is implemented in a particularly integrated manner and the cooling fluid can be used simultaneously to cool the rotating parts of the pump device. This can be further improved in that one of the channel regions extends between the rotor and the stator and / or another channel region extends through the rotor.

[0026] In addition, in an advantageous embodiment, the drive unit comprises a control / regulatory device for controlling an electric motor having a stator and a rotor. Preferably, the control / regulatory device is arranged in the dry area of ​​the pump device. The control / regulatory device comprises a circuit board on which at least one electrical / electronic structural element is arranged. These structural elements can be, for example, sensors, capacitors, coils, resistors, switches (in particular semiconductor switches) and integrated circuits. In addition, in this embodiment, the sensor unit is electrically connected to the circuit board. In this way, the control of the sensor unit can be achieved directly via the circuit board or by means of electrical / electronic structural elements arranged on the circuit board. Therefore, there is no need for a separate electrical wiring of the sensor unit to the outside; more precisely, the complete electrical control of the sensor unit can be achieved via the circuit board.

[0027] According to an advantageous further development, the sensor unit can also be arranged on a circuit board. Thus, the sensor unit can be implemented, for example, as an SMD component. The sensor unit and the circuit board are then part of a circuit board assembly (PCBA). Thus, the sensor unit can be preassembled directly or already preassembled on the circuit board during the manufacturing process of the pump device. In addition, in this further development, it is possible to dispense with providing electrical connection lines between the circuit board and the sensor unit, which is therefore associated with both structural space advantages and cost advantages.

[0028] In order to ensure good heat conduction, the circuit board is preferably connected to the fluid channel wall in a heat-conducting manner by means of a heat-conducting layer, in particular directly connected in a heat-conducting manner. Generally speaking, the fluid channel wall, the heat-conducting layer and the circuit board are preferably stacked one on top of the other.

[0029] In general, preferably, the electrical components of the circuit board assembly are at least mainly arranged on one side of the circuit board in order to simplify production. Therefore, preferably, at least one sensor, in particular the sensor unit, is arranged on the side of the circuit board pointing away from the fluid channel. This allows a space-saving embodiment and allows a simpler configuration of the circuit board assembly. Preferably, more than 50%, in particular more than 85%, in particular all of the electrical / electronic components arranged on the circuit board are arranged on the side of the circuit board pointing away from the fluid channel. By arranging as many components as possible on this side pointing away from the fluid channel, the circuit board can be arranged closer to the fluid channel.

[0030] When the pump device is running, the circuit board may generate heat due to the resistance of the electrical / electronic components and the conductor circuit or integrated circuit of the circuit board, for example. Thus, the circuit board or the circuit board assembly is a heat source. This self-heating can affect the determination of the measured variable, especially the fluid temperature. Therefore, according to an advantageous extension scheme, another temperature sensor for detecting the temperature of the circuit board is also arranged on the circuit board. The sensor unit and the other temperature sensor are spaced apart and act together so that when determining the measured variable characterizing the cooling fluid, by comparing with the circuit board temperature detected by the other temperature sensor, the influence of the self-heating of the circuit board on the measured variable can be considered or has been considered. Advantageously, the thermal coupling of the other temperature sensor to the fluid channel is kept negligibly small. Particularly preferably, the other temperature sensor is arranged next to the fluid channel in a non-overlapping manner relative to the rotation axis of the rotor in the radial direction for this purpose. In particular, the circuit board is spaced apart from the fluid channel wall by an intermediate space at the height of the other temperature sensor. The intermediate space ensures that the thermal coupling of the circuit board to the fluid channel occurs outside the position where the other temperature sensor is arranged.

[0031] In an advantageous embodiment, in particular in addition, the self-heating can be taken into account in other ways when evaluating the signals of the sensors of the sensor unit to determine the measured variable. To this end, according to a particularly preferred embodiment, the power consumption of the circuit board assembly, i.e. the power consumption of the circuit board and the electrical / electronic components arranged thereon, is detected by a controller on the circuit board, and the difference associated therewith is subtracted from the signal of at least one sensor. Thus, if the sensor is designed as a temperature sensor, the power consumption of the circuit board assembly can be detected by means of the controller, and the difference associated therewith can be subtracted as a temperature difference from the signal detected by the temperature sensor. This further approaches the accuracy of the temperature measurement when the sensor is arranged directly in the cooling fluid.

[0032] According to one embodiment, the circuit board is pressed against, in particular directly against, a fluid channel wall of the fluid channel. This improves the heat conduction between the fluid channel and the temperature sensor arranged on the circuit board. In some embodiments, a heat conducting layer can be omitted, for example.

[0033] According to one embodiment, at least one sensor of the sensor unit is arranged on the side of the circuit board that is directed toward the fluid channel, which improves the thermal coupling of the sensor and the fluid channel. In addition, this ensures that the sensor or the sensor unit can be arranged in a recess in the wall of the fluid channel, which also contributes to a compact design. In particular, the sensor or the sensor unit is pressed against the wall of the fluid channel.

[0034] According to an advantageous embodiment, the sensor unit can be electrically connected to the printed circuit board by means of at least one cutting and clamping connection or by means of at least one plug connection. This facilitates removal of the sensor unit from the printed circuit board, if this is necessary.

[0035] According to an advantageous embodiment, the control / regulatory device can include a voltage supply for supplying electrical energy to the electric motor. In this embodiment, the sensor unit is electrically connected to the voltage supply for supplying electrical energy to at least one sensor. Thus, it is possible to dispense with providing a separate electrical connection of the sensor unit to such a voltage supply. More precisely, the sensor unit can be supplied with electrical energy via the voltage supply of the control / regulatory device. This significantly simplifies the electrical wiring of the sensor unit, which is also associated with significant cost advantages.

[0036] According to an advantageous embodiment, the control / regulator comprises a communication unit for communicating with an external field bus, in particular a LIN bus or a CAN bus of a motor vehicle. In this embodiment, the sensor unit is electrically connected and / or connected in a data transmission manner to the controller and / or the communication unit for reading or controlling at least one sensor. This enables flexible control or reading of the sensor unit from the outside via the field bus without requiring a separate communication unit for this purpose. More precisely, the communication unit of the control / regulator can be used simultaneously for controlling or reading the sensor unit.

[0037] According to a preferred embodiment, the temperature measured by the sensor and the phase current of the electric machine ascertained by the control / regulator and in particular the rotational speed of the pump rotor can be processed, in particular in the control / regulator, by means of the correlation between the pressure, temperature and phase current and in particular the rotational speed stored in the control / regulator to calculate the pressure of the cooling fluid. Particularly preferably, the pump device is also designed to transmit data about the calculated pressure via the control / regulator, in particular via a communication unit for communicating with an external field bus. As a result, a pressure sensor in the fluid channel can be omitted and the pressure present in the pump device can still be at least approximately ascertained.

[0038] In a preferred embodiment, the pump device is designed to process, in particular in the control / regulator, the temperature measured by the temperature sensor as at least one sensor and the rotational speed of the pump rotor and in particular the phase current of the electric machine ascertained by the control / regulator, with the aid of the correlation between the pressure, temperature and phase current and in particular the rotational speed stored in the control / regulator, in order to calculate the mass flow and / or volume flow of the cooling fluid. Particularly preferably, the pump device is furthermore designed to transmit data about the calculated mass flow or volume flow via the control / regulator, in particular via a communication unit for communicating with an external field bus. As a result, a mass flow sensor in the fluid channel can be omitted and the mass flow of the cooling fluid in the fluid channel can still be ascertained at least approximately.

[0039] However, the embodiment of directly detecting pressure or mass flow / volume flow is also in the framework of the present invention. In a preferred embodiment, the sensor unit can have at least two sensors of the sensors described below. Such a sensor can be a pressure sensor for obtaining the fluid pressure of the cooling fluid guided through the fluid channel. Therefore, it is possible to accurately determine at what pressure the cooling fluid is delivered by the pump device. Another sensor of the sensor unit can be a temperature sensor for obtaining the cooling fluid temperature of the cooling fluid guided through the fluid channel. Therefore, it is possible to very accurately determine the fluid temperature of the cooling fluid guided through the fluid channel. In particular, this is proven to be important when the cooling fluid should receive the waste heat of the components to be cooled. In this embodiment, another sensor of the sensor unit can be a mass flow sensor for obtaining the mass flow of the cooling fluid through the fluid channel. In this way, the instantaneous delivery amount of the cooling fluid delivered by the pump device can be accurately determined. In this embodiment, another sensor of the sensor unit can include a conductivity sensor for obtaining the conductivity of the cooling fluid guided through the fluid channel. Therefore, it is also possible to accurately determine the conductivity of the cooling fluid. When the fluid channel is bounded by a component made of metal, exact knowledge of the electrical conductivity of the cooling fluid can prove to be advantageous, since a cooling fluid with an electrical conductivity that is too high can lead to electrical short circuits. However, it is also conceivable to use at least one further sensor for determining other measured variables in combination with at least one of the sensors mentioned above.

[0040] According to an advantageous embodiment, the sensor unit comprises a sensor housing in which and / or on which at least one sensor is arranged. In this embodiment, at least the at least one sensor and the sensor housing are also designed as a structural unit, in particular as an SMD structural unit. This embodiment is particularly compact and can also be mounted in the housing of the pump device particularly easily and in a space-saving manner.

[0041] According to another advantageous embodiment, the drive shaft is designed as a hollow shaft, preferably a hollow cylindrical hollow shaft, which surrounds a cavity, preferably a cylindrical cavity, which forms part of the fluid channel. In this way, the cavity serves as a passage for the cooling fluid. In this embodiment, the flow path of the cooling fluid extends through the drive shaft. Particularly preferably, one of the channel regions extends through the hollow shaft to the pump rotor.

[0042] In this embodiment, the sensor unit is arranged in the fluid channel in the axial extension of the cavity, thereby ensuring a reliable incident flow in the region of the sensor unit.

[0043] In an advantageous embodiment, the rotor has an axial through-hole leading to the pump rotor. In this embodiment, the cooling channel extends through the through-hole. In this way, the flow path of the cooling fluid can extend through the rotor. Particularly preferably, one of the two channel areas extends to the pump rotor through the through-hole of the rotor. Preferably, the through-hole is radially constructed between the retaining section and the magnet section, which is radially spaced apart from the retaining section. The retaining section and the magnet section are rigidly connected to each other, in particular, they are connected to each other by injection molding with plastic. The rotor is fastened to the drive shaft with the help of the retaining section. The rotor is implemented at least in the magnet section in a permanent magnetic manner, in particular, so that at least one permanent magnet is arranged in the magnet section. In the extended scheme, the rotor therefore constitutes a part of the fluid channel between the magnet section and the retaining section. This can achieve better integration of the cooling channel and at the same time allow effective cooling of the rotor with the help of the cooling fluid.

[0044] The inventors have found that the high flow velocity of the cooling fluid improves the heat transfer to the temperature sensor. In order to produce favorable flow conditions, the pump device can have a delivery geometry along the fluid channel, which can achieve a higher flow velocity. The delivery geometry works together with the cooling fluid in a delivery-effective manner for conveying the cooling fluid. According to one embodiment, at least one delivery geometry is constructed in the hollow shaft. When the hollow shaft rotates, the delivery geometry works together with the cooling fluid so that the cooling fluid is conveyed through the hollow shaft. Accordingly, in an advantageous embodiment, the rotor can have, especially in the through-port, at least one delivery geometry. When the rotor rotates, the delivery geometry works together with the cooling fluid so that the cooling fluid is conveyed through the rotor and / or passes by the rotor. On other areas of the fluid channel, especially in the first and / or second channel area, this type of delivery geometry can also be considered.

[0045] According to an advantageous embodiment, the sealing device is arranged axially between the pump rotor and the rotor for sealingly connecting the rotor to the housing. Preferably, the sealing device is implemented as a labyrinth seal. The sealing device provides a sealing gap between the rotor and the housing. The sealing gap ensures a sealed connection on the one hand and allows a prescribed relative movement of the rotor relative to the housing on the other hand for driving the drive shaft. To this end, the sealing device has a first sealing part connected rigidly, especially in an integral manner, to the rotor and a second sealing part connected rigidly, especially in an integral manner to the housing. The sealing gap is formed between the sealing parts. Preferably, the sealing device is arranged on both sides of the sealing device in opposite directions respectively for allowing the cooling fluid to flow past. In particular, the sealing device separates the two channel areas from each other. Preferably, the gap width of the sealing gap is a maximum of 2 mm, in particular a maximum of 1 mm and in particular at least 0.2 mm. Since only a negligible small portion of the cooling fluid can pass through the sealing gap, sufficient sealing is ensured. In one embodiment, the sealing device is implemented to delimit the fluid channel in such a way that the cooling fluid guided in the direction toward the sensor unit reaches the pump rotor from the side of the sealing device. In one embodiment, the sealing device is designed to delimit the fluid channel in such a way that the cooling fluid is guided past the sealing device in the direction toward the sensor unit. As a result, the cooling fluid flowing through the rotor is reliably conducted to the pump rotor without significantly mixing with the cooling fluid in other channel areas.

[0046] Particularly preferably, the housing is constructed in at least two parts, preferably in three parts, with a housing body and at least one, preferably two housing covers, in which the drive unit is arranged. In this variant, at least one housing cover is fastened to the housing body in a releasable manner, preferably by means of at least one screw connection. In addition, in this variant, the sensor unit, preferably also the circuit board, is fixedly connected to a housing cover. Thus, the sensor unit can be mounted on the pump device during the process of mounting the housing cover on the housing body, and the sensor unit can also be pre-mounted on the housing cover. This simplifies the assembly of the pump device.

[0047] The invention further relates to a cooling device for a fuel cell system of a motor vehicle. The cooling device comprises a cooling circuit for circulating a cooling fluid, in particular water or cooling water, and a pump device according to the invention arranged in the cooling circuit for conveying the cooling fluid in the cooling circuit. The advantages of the pump device according to the invention explained above are thus transferred to the cooling device according to the invention.

[0048] The invention further relates to a motor vehicle having a pump device according to the invention, wherein the motor vehicle comprises a drive train having a component that generates waste heat, which is thermally coupled to a cooling circuit so that the generated waste heat can be transferred to a cooling fluid circulating in the cooling circuit. The component that generates waste heat can be, for example, an electric motor, an internal combustion engine or a fuel cell. The motor vehicle according to the invention can include the features described above in conjunction with the pump device according to the invention.

[0049] The invention further relates to a motor vehicle having a cooling device according to the invention as described above. The advantages of the pump device according to the invention as described above are thus transferred to the motor vehicle according to the invention. According to one embodiment, the motor vehicle comprises a fuel cell system which generates waste heat and is thermally coupled to the cooling device so that the waste heat generated can be transferred to a cooling fluid circulating in a cooling circuit.

[0050] The invention further relates to a method for determining a measured variable, in particular a thermodynamic measured variable, in particular a fluid temperature, which characterizes a cooling fluid in a pump device according to the invention. In the method, a cooling fluid is guided in a fluid channel in the direction of a sensor unit. Heat or thermal energy is transferred from the cooling fluid guided in the direction of the sensor unit to the sensor unit by flowing into the fluid channel and via a thermally conductive coupling of the fluid channel and the sensor unit. A sensor of the sensor unit detects the thermal energy transferred to the sensor unit by temperature measurement, wherein the sensor unit preferably determines the measured variable. The cooling fluid guided in the direction of the sensor unit is directed away from the sensor unit.

[0051] According to a preferred embodiment, the cooling fluid is deflected along the flow path of the cooling fluid at the level of at least one sensor of the sensor unit from one channel region of the fluid channel to an inlet opening into another channel region of the fluid channel.

[0052] The method can have the features described above in conjunction with the pump system, the motor vehicle or the cooling device.

[0053] Further important features and advantages of the invention emerge from the dependent claims, the drawings and the associated description of the figures with the aid of the drawings.

[0054] It goes without saying that the features mentioned above and those yet to be explained below can each be used not only in the respectively stated combination but also in other combinations or alone without departing from the scope of the present invention.

[0055] Preferred exemplary embodiments of the invention are shown in the drawings and are explained in more detail in the following description, wherein identical reference numerals refer to identical or similar components or components having the same function. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] The accompanying drawings show:

[0057] Figure 1 A cross-sectional view showing an example of a pump device according to the first aspect of the present invention;

[0058] Figure 2 A cross-sectional view of an exemplary embodiment of a pump device according to the second aspect of the invention is shown. DETAILED DESCRIPTION

[0059] Figure 1 The present invention shows a sectional view of an example of a pump device 1 which is designed as a water pump. The pump device 1 is used to convey a cooling fluid W, in particular water, in particular cooling water. The pump device 1 comprises a housing 2, in which a fluid channel 3 is arranged, through which the cooling fluid W to be conveyed can flow. In addition, the pump device 1 comprises an electric drive unit 4, which is arranged according to Figure 1 In the example of FIG. 1 , the electric drive unit 4 is partially arranged in the fluid channel 3 and is used to drive the cooling fluid W guided through the fluid channel 3. The drive unit 4 of the pump device 1 has a rotatable drive shaft 7 arranged in the fluid channel 3, on which a pump rotor 8 designed as an impeller is arranged in a rotationally fixed manner, and is used to convey water as the cooling fluid W in the fluid channel 3.

[0060] In addition, according to Figure 1The pump device 1 of the embodiment ... The third sensor 6c of the four sensors 6a-6d of the sensor unit 5 is a mass flow sensor, which is used to determine the mass flow of the cooling fluid W through the fluid channel 3. In this way, the instantaneous delivery amount of the cooling fluid delivered by the pump device can be accurately determined. The fourth sensor 6d of the four sensors 6a-6d of the sensor unit 5 is a conductivity sensor, which is used to determine the conductivity of the cooling fluid W guided through the fluid channel 3. In this way, the conductivity of the cooling fluid W can also be accurately determined. In particular, when the fluid channel 3 is bounded by a component made of metal, an accurate knowledge of the conductivity of the cooling fluid W can prove to be important, because in the case of too high a conductivity, the cooling fluid W can cause an electrical short circuit.

[0061] The sensor unit 5 can expediently be equipped with a sensor housing 17 in which or on which the four sensors 6a-6d are arranged. In this embodiment, the four sensors 6a-6d and the sensor housing 17 are also designed as a structural unit.

[0062] The drive unit 4 comprises an electric motor 9 having a stator 10 and a rotor 11 for driving the drive shaft 7. Figure 1As shown, the drive shaft 7 can be configured as a hollow shaft 18 with a hollow cylindrical geometry, which surrounds a cylindrical cavity 19 on the circumferential side and is open on both sides in the axial direction. The cavity 19 forms a part of the fluid channel 3. Here, the sensor unit 5 with sensors 6a-6d extends into the fluid channel 3 in the region of the axial extension 20 of the cavity 19. Here, the stator 10 is arranged in a fixed position relative to the housing 2, and the rotor 11 is connected to the drive shaft 7 in a rotationally fixed manner, so that when the pump device 1 is running, a relative rotational movement occurs between the rotor 11 and the stator 10. Here, the rotor 11 performs a rotational movement around the rotation axis D, which is consistent with the central longitudinal axis M of the drive shaft 7. The central longitudinal axis M extends along the axial direction A. The drive shaft 7 can be rotatably arranged on the housing 2 of the pump device 1 or on another component (not shown) that is fixed relative to the housing 2 by means of a suitable bearing element (not shown).

[0063] like Figure 1 As shown, the rotor 11 may be arranged in the fluid channel 3. The stator 10 may delimit the fluid channel 3 in a section of the fluid channel 3 where the rotor 11 is arranged. Therefore, the cooling fluid W flowing through the fluid channel 3 may cool not only the stator 10 but also the rotor 11.

[0064] In addition, the drive unit 4 comprises a control / regulator 12 for controlling the motor 9. The control / regulator 12 comprises a circuit board 13 on which electrical and electronic components are arranged. These components can be, for example, capacitors, coils, resistors, switches (especially semiconductor switches) and integrated circuits (not shown). The sensor unit 5 is electrically connected to the circuit board 13. Therefore, the electrical control of the sensor unit 5 and its sensors 6a-6d can be carried out directly via the circuit board 13 or by means of electrical / electronic components arranged on the circuit board 13. Therefore, there is no need for a separate wiring of the sensor unit 5 to the outside; more precisely, the complete electrical application of the sensor unit can be realized via the circuit board 13. In this example scenario, the sensor unit 5 is arranged directly on the circuit board 13. Therefore, it is possible to save the provision of an electrical connection line between the circuit board and the sensor unit. Optionally, the sensor unit 5 can be electrically connected to the circuit board 13 by means of a suitable cutting and clamping connection and an appropriate plug connection, which simplifies the possible necessary disassembly of the sensor unit 5 from the circuit board 13.

[0065] In this example, the control / regulator 12 comprises a voltage supply 14 for supplying electrical energy to the motor 9. Here, the sensor unit 5 is electrically connected to the voltage supply 14 for supplying electrical energy to at least one sensor 6. Therefore, it is possible to dispense with the provision of a voltage supply 14 and the provision of a separate electrical connection of the sensor unit 5 to such a voltage supply. Instead, the sensor unit 5 can be supplied with electrical energy via the voltage supply 14 of the control / regulator 12. As a result, the electrical wiring of the electrical sensor unit 5 is significantly simplified, which is also accompanied by significant cost advantages. In addition, the control / regulator 12 comprises a communication unit 15 for communicating with an external field bus (not shown), in particular a LIN bus or a CAN bus of a motor vehicle. Here, the sensor unit 5 is electrically connected to the communication unit 15 and is also connected in a data transmission manner for controlling four sensors 6a-6d. This enables flexible control of the sensor unit 5 from the outside, in particular via the field bus, without requiring a separate communication unit for this purpose. Instead, the communication unit 15 of the control / regulator 12 can be used to control the sensor unit 5.

[0066] exist Figure 1 In the example of , the housing 2 is constructed in three parts with a housing body 2a and two housing covers 2b and 2c opposite to each other, in which a drive unit 4 is arranged, wherein, as shown in the figure, the housing body 2a can be arranged in a sandwich manner between the two housing covers 2b and 2c. The two housing covers 2b and 2c are respectively fastened to the housing body 2a in a releasable manner by means of a screw connection 16. The sensor unit 5 and the circuit board 13 are respectively fixedly connected to the first housing cover 2b of the two housing covers 2b and 2c. Therefore, the sensor unit 5 can be pre-assembled on the first housing cover 2b in the process of assembling the pump device 1. This facilitates the assembly of the pump device 1.

[0067] Figure 2 A schematic longitudinal section shows an exemplary embodiment of a pump device 1 according to the second aspect of the invention. Figure 2 The embodiments of the present invention are similar in many aspects to those according to Figure 1 Therefore, reference is made to the above description with respect to the consistent features and supplements are made below. Figure 2The pump device 1 in the embodiment is used for conveying oil as a cooling fluid W. The pump device 1 has a housing 2, which has a housing cover 2a, 2c and a housing body 2b, in which a fluid channel 3 with a plurality of channel areas 3a, 3b extends between a stator 10 and a rotor 11 of an electric motor 9 and through an axial through-hole of the rotor 11 to a pump rotor 8. The pump rotor 8 and the rotor 11 are connected in a rotationally fixed manner via a drive shaft 7. The pump device 1 is divided into a wet area and a dry area by a gap pot 23. The stator 10 and the electrical / electronic components are arranged in the dry area. The fluid channel 3 extends in the wet area and the rotor 11 is arranged in the wet area.

[0068] The passage of the rotor 8 is formed radially between the retaining section 111 and the magnet section 112. The retaining section 111 serves to fasten the rotor to the drive shaft 7. The magnet section 112 is designed to be permanently magnetic and contains a permanent magnet.

[0069] A sealing device 21 is arranged axially between the pump rotor 8 and the rotor 11, which sealing device is implemented as a labyrinth seal and serves to seal the region between the rotor 11 and the housing 2 through which the cooling fluid W would otherwise flow. The sealing device 21 provides a sealing gap 22 through which only a negligible small portion of the cooling fluid W can pass. As a result, the cooling fluid W flowing through the rotor 11 is reliably conducted to the pump rotor 8 without significantly mixing with the cooling fluid W in other channel regions.

[0070] with Figure 1 In contrast to the exemplary embodiment of the embodiment of the invention, the drive shaft 7 is designed as a solid shaft. Instead of a cavity of a hollow shaft as part of the fluid channel, the rotor 11 is provided with an axial through-hole between the retaining section 111 and the magnet section 112, through which the cooling fluid W can flow. This through-hole is part of the fluid channel 3. However, an embodiment with a hollow shaft is also within the scope of the invention, so that the fluid channel can extend through the hollow shaft, in particular, to the pump rotor 8 in addition to passing through the rotor 11.

[0071] In accordance with Figure 2 In the embodiment of the invention, the pump device is implemented as a cycloidal rotor pump. Therefore, the pump rotor 8 is implemented as a cycloidal rotor, in particular a multi-stage cycloidal rotor. The individual cycloidal rotor steps are not shown in the schematic diagram. Multi-stage cycloidal rotor pumps are known and are described, for example, in German patent application DE 102021 214 256A1 or international patent application WO 00 / 42321A1.

[0072] The flow path of the cooling fluid W through the channel area 3a between the rotor 11 and the stator 10 is indicated by means of arrows. The pump device is implemented essentially rotationally symmetrically in the area of ​​the rotor 11 and the stator 10, so that the cooling fluid W can of course flow through the rotor 11 on both sides of the rotation axis D shown. The points drawn in the area of ​​the pump rotor 8 represent the delivery of the cooling fluid W in the pump rotor 8 perpendicular to the rotation axis of the pump rotor 8 from the suction side to the pressure side. The cooling fluid in the pump rotor is squeezed from the suction side to the pressure side. In general, the present invention of course also includes the following embodiments: in the embodiment, the flow path of the cooling fluid is reversed, that is, the suction side and the pressure side are interchanged. In such an embodiment, the cooling fluid flows from the pressure side through the rotor 11 or the drive shaft 7.

[0073] The gap pot 23 forms a fluid channel wall 3c on its pot bottom. When the cooling fluid W is conveyed through the fluid channel 3, the cooling fluid W flows along the flow path to the fluid channel wall 3c. Thus, good heat transfer from the cooling fluid to the fluid channel 3 or its fluid channel wall 3c is achieved.

[0074] Furthermore, the pump device 1 comprises a sensor unit 5. The sensor unit is arranged on the side of the circuit board 13 of the control / regulating device 12 of the pump device 1 that points away from the cooling channel 3. The sensor unit 5 has a sensor 6 that is embodied as a temperature sensor 61. A further temperature sensor 62 is arranged on the circuit board 13 at a distance from the sensor. Preferably, the further temperature sensor 62 is arranged in such a way that the heat flow transferred from the fluid channel 3 to the further temperature sensor 62 by heat conduction is at most 30% of the heat flow transferred from the fluid channel 3 to the sensor 6 of the sensor unit. As a result, the further temperature sensor 62 mainly detects the self-heating of the circuit board 13 associated with the relevant electrical power. The temperature sensor 61 of the sensor unit 5, on the other hand, is used to determine the fluid temperature of the cooling fluid W and is coupled to the fluid channel 5 in a heat-conducting manner for this purpose.

[0075] A gap filler is arranged between the circuit board 13 and the fluid channel 3 or the gap pot 23 or the fluid channel wall 3c, and the gap filler is arranged as a heat conductive layer 24 in contact with the fluid channel 3 and the circuit board 13. The heat conductive layer 24 ensures good heat conduction between the fluid channel and the circuit board 13, wherein the sensor 6 as a temperature sensor is coupled to the fluid channel 3 in a heat conductive manner via the circuit board 13 and the heat conductive layer 24.

[0076] The heat conducting layer 24 extends across the entire gap pot bottom. The circuit board 13 extends radially across the fluid channel wall 3c and the heat conducting layer 24. The fluid channel wall 3c, the heat conducting layer 24 and the circuit board 13 are connected in a heat conducting manner over the entire area where they overlap.

[0077] When it is ensured that the cooling fluid W flows continuously toward the fluid channel wall 3c, the quality of the heat transfer from the cooling fluid to the fluid channel 5 or the sensor 6 is significantly improved. Therefore, the sensor 6 or the sensor unit 5 and the fluid channel 3 are coordinated in their arrangement. The cooling fluid W guided through the channel area 3a in the direction toward the sensor unit 5 flows toward the fluid channel wall 3c while transferring heat to the fluid channel wall 3c and is deflected by the fluid channel wall in such a way that the cooling fluid W is directed away from the sensor unit 5 or the sensor 6 through the channel area 3b. Here, the sensor 6 is arranged at the height of the following position: the deflection occurs at this position, so that the shortest possible distance is provided for transferring heat from the fluid channel 3 to the sensor 6 by heat conduction.

[0078] Reference numerals list

[0079] 1 Pump equipment

[0080] 2 Housing

[0081] 2a Housing body

[0082] 2b, 2c Housing cover

[0083] 3 Fluid channels

[0084] 3a, 3b channel area

[0085] 3c Fluid channel wall

[0086] 4 Drivers

[0087] 5 Sensor unit

[0088] 6 Sensors

[0089] 6a First sensor

[0090] 6b Second sensor

[0091] 6c Third sensor

[0092] 6d Fourth sensor

[0093] 7 Drive shaft

[0094] 8 Pump rotor

[0095] 9 Motor

[0096] 10 Stator

[0097] 11 Rotor

[0098] 12 Control / regulation device

[0099] 13 Circuit Board

[0100] 14 Voltage supply device

[0101] 15 Communication Unit

[0102] 16 Screw connection

[0103] 17 Sensor housing

[0104] 18 Hollow shaft

[0105] 19 Cavity

[0106] 20 Axial extension

[0107] 21 Sealing device

[0108] 22 Sealing gap

[0109] 23 Clearance tank

[0110] 24 Thermal Conductive Layer

[0111] 61 Temperature sensor

[0112] 62 Temperature sensor

[0113] 111 Keep section

[0114] 112 Magnet Segment

[0115] A Axial direction

[0116] D Rotation axis

[0117] M Center longitudinal axis

[0118] W Cooling fluid

Claims

1. A pump device (1) for a cooling device of a motor vehicle, in particular for a fuel cell system, and for conveying a cooling fluid (W), in particular cooling water and / or oil, The pump device has a housing (2), in which a fluid channel (3) is arranged, through which a cooling fluid (W) to be conveyed can flow, the pump device has a drive unit (4) for driving the cooling fluid (W) guided through the fluid channel (3), The pump device has an electrical sensor unit (5) comprising at least one sensor (6) for determining at least one measured variable characterizing the cooling fluid (W), in particular the fluid temperature, wherein: The sensor unit (5) is at least partially arranged in the fluid channel (3), preferably projects into the fluid channel (3), and / or At least one sensor (6) of the sensor unit (5) implemented as a temperature sensor (61), is arranged outside the fluid channel (3), and The fluid channel (3), in particular the fluid channel wall (3c), is coupled in a heat-conducting manner.

2. The pump device (1) according to claim 1, wherein: the drive unit (4) comprises a rotatable drive shaft (7) having a pump rotor (8), in particular an impeller, for conveying the cooling fluid (W) in the fluid channel (3), and the drive unit comprises an electric motor (9) having a stator (10) and a rotor (11) for driving the drive shaft (7) having the pump rotor (8), in particular the impeller, the drive unit (4) further comprises a control / regulatory device (12) for controlling the electric motor (9), wherein the control / regulatory device (12) has a printed circuit board (13) on which at least one electrical / electronic component is arranged, - The sensor unit (5) is electrically connected to the circuit board (13).

3. The pump device (1) according to claim 2, wherein: The sensor unit (5) is arranged on the printed circuit board (13), wherein in particular the temperature sensor (61) is coupled to the fluid channel (3) via the printed circuit board (13) in a heat-conducting manner.

4. The pump device (1) according to any one of claims 2 to 3, wherein: The pump device (1) has a gap pot (23) which separates a dry area from a wet area in a fluid-tight manner, in which a stator (10) of the motor (9) is arranged, and in which a rotor (11) of the motor (9) is arranged and in which the fluid channel (3) extends, wherein in particular the fluid channel wall (31) is formed at least in sections by the gap pot (23).

5. The pump device (1) according to any one of claims 1 to 4, wherein: The fluid channel (3) has two channel areas (3a, 3b), which are arranged in sequence along a flow path of the cooling fluid (W), one of the two channel areas (3a, 3b) being implemented for guiding the cooling fluid in a direction toward the sensor unit (5), and the other of the two channel areas (3a, 3b) being implemented for guiding the cooling fluid (W) guided in a direction toward the sensor unit (5) away from the sensor unit (5), wherein in particular the fluid channel (3) is implemented for diverting the cooling fluid (W) along the flow path from one of the channel areas (3a, 3b) to an inlet in the other of the channel areas (3a, 3b) at a height of at least one sensor (6) of the sensor unit (5).

6. The pump device (1) according to any one of the preceding claims 2 to 5, wherein: The rotor (11) has an axial through-portion leading to the pump rotor (8), and / or the pump device (1) comprises a sealing device (21), which is arranged axially between the pump rotor (8) and the rotor (11) for sealingly connecting the rotor (11) and the housing (2), wherein the sealing device (21) provides a sealing gap between the rotor and the housing, and the sealing gap is formed between a first sealing part connected to the rotor and a second sealing part connected to the housing.

7. The pump device (1) according to any one of claims 2 to 6, wherein: An additional temperature sensor (62) for detecting the temperature of the circuit board is arranged on the circuit board (13), wherein the sensor unit (5) and the additional temperature sensor (62) are spaced apart and act together in such a way that when determining a measured variable characterizing the cooling fluid (W), in particular the fluid temperature, the influence of the self-heating of the circuit board on the measured variable can be taken into account by comparing it with the circuit board temperature detected by the additional temperature sensor.

8. A pump device according to any one of claims 2 to 7, wherein: the control / regulator (12) comprises a voltage supply (14) for supplying electrical energy to the motor (9), The sensor unit (12) is electrically connected to the voltage supply device (14) for supplying electrical energy to the at least one sensor (6).

9. The pump device (1) according to any one of claims 2 to 8, wherein: the control / regulator (12) comprises a communication unit (15) for communicating with an external field bus, in particular a LIN bus or a CAN bus of a motor vehicle, The sensor unit (5) is electrically connected to the communication unit (15) or / and is connected in a data transmission manner to control the at least one sensor (6).

10. The pump device (1) according to any one of the preceding claims, wherein: The sensor unit (5) comprises at least two of the following sensors, namely: a pressure sensor for determining the fluid pressure of the cooling fluid (W) guided through the fluid channel (3), a temperature sensor, in particular a temperature sensor for ascertaining the fluid temperature of a cooling fluid (W) conducted through the fluid channel (3), a mass flow sensor for determining the mass flow of the cooling fluid (W) through the fluid channel (3), and / or A conductivity sensor for determining the conductivity of a cooling fluid (W) conducted through the fluid channel.

11. The pump device (1) according to any one of the preceding claims, wherein: the sensor unit (5) comprises a sensor housing (17), in and / or on which the at least one sensor (6a, 6b, 6c, 6d) is arranged, At least the at least one sensor (6a, 6b, 6c, 6d) and the sensor housing (17) are designed as a structural unit.

12. The pump device (1) according to any one of claims 2 to 11, wherein: the drive shaft (7) is designed as a hollow shaft (18), preferably a hollow cylindrical shaft, which surrounds a cavity (19), preferably a cylindrical cavity, which forms part of the fluid channel (3), The sensor unit (5) is arranged in the fluid channel (3) in an axial extension (20) of the cavity (19).

13. A water pump according to any one of the preceding claims, wherein: the housing (2) is constructed in at least two parts, preferably in three parts, with a housing body (2a) and at least one, preferably two housing covers (2b, 2c), in which the drive unit (4) is arranged, and the housing cover is detachably fastened to the housing body (2a), preferably by means of at least one screw connection (16), The sensor unit (5), preferably also the printed circuit board (13), is fixedly connected to a housing cover (2b).

14. A motor vehicle, comprising: - a cooling device having a cooling circuit for circulating a cooling fluid (W), a pump device (1) according to any one of the preceding claims, arranged in the cooling circuit, for conveying the cooling fluid (W) in the cooling circuit, The motor vehicle further comprises a drive train having components which generate waste heat and are thermally coupled to the cooling circuit in order to transfer the generated waste heat to a cooling fluid circulating in the cooling circuit.

15. A method for determining a measured variable, in particular a fluid temperature, which characterizes a cooling fluid (W) in a pump system (1) according to any one of claims 1 to 13, wherein: - guiding the cooling fluid (W) in the fluid channel (3) in the direction towards the sensor unit (5), - transferring heat of the cooling fluid (W) directed in the direction of the sensor unit (5) to the sensor unit (5) by flowing to the fluid channel (3) and via the thermally conductive coupling of the fluid channel (3) and the sensor unit (5), - the sensor (6) of the sensor unit (5) detects the heat transferred to the sensor unit (5), and in particular the sensor unit (5) determines the measured variable, and - directing the cooling fluid (W) directed in the direction towards the sensor unit (5) away from the sensor unit (5), Among them, in particular, - diverting the cooling fluid (W) along the flow path of the cooling fluid (W) from one channel area (3a, 3b) of the fluid channel (5) at the height of at least one sensor (6) of the sensor unit (5) to an inlet in another channel area (3a, 3b) of the fluid channel (5).

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