Pump device for a motor vehicle

Abstract

The invention relates to a pump device (1) for conveying cooling fluid W. The pump device (1) comprises a housing (2) in which a fluid channel (3), through which the cooling fluid W to be conveyed can flow, is arranged, and a drive unit (4) for driving the cooling fluid W guided through the fluid channel (3). Furthermore, the pump device (1) comprises an electric sensor unit (5) that comprises at least one sensor (6), more particularly a temperature sensor for determining at least one measurement variable that characterises the cooling fluid. The sensor unit (5) can be arranged at least partially in the fluid channel (3). The sensor (6) can be arranged as a temperature sensor outside the fluid channel (3) and be coupled thereto in a heat-conducting manner.

Description

[0001] Pumping device for a motor vehicle

[0002] The invention relates to a pumping device, such as an oil pump, a water pump or the like, for a motor vehicle or for a cooling device of a motor vehicle, in particular a fuel cell system, and for conveying cooling fluid, in particular oil, water or cooling water or the like. The invention further relates to such a motor vehicle, such a cooling device, and a motor vehicle with such a cooling device and / or with a fuel cell system. Such pumping devices can be designed in various ways, for example as a centrifugal pump, gerotor pump, rotary vane pump or the like. Finally, the invention also relates to a method for determining a measured variable, in particular a fluid temperature, which characterizes a cooling fluid in a pumping device according to the invention.

[0003] With the help of a cooling fluid, components of a motor vehicle that generate waste heat, such as its powertrain, especially a fuel cell system, can be cooled by absorbing and transporting the resulting waste heat. Similarly, the cooling fluid can also be used to cool electrical or electronic components of the motor vehicle that generate waste heat.

[0004] In both cases, the cooling fluid is typically circulated in a cooling circuit. A pumping device is typically used to drive or pump the cooling fluid in the cooling circuit. To ensure its proper function, it is important to know various parameters or measured variables as accurately as possible, such as the fluid temperature of the pumped cooling fluid, the fluid pressure of the pumped cooling fluid, the pumped mass flow and thus the pumping capacity of the pumping device, and / or the electrical conductivity of the cooling fluid. Suitable sensors can be provided in the cooling circuit for this purpose.

[0005] Such sensors are typically arranged along the cooling circuit in contact with the cooling fluid. For example, DE102009005154A1 discloses a pumping device with various sensors for detecting measured variables. DE1983928U discloses a pumping device with a temperature sensor arranged in the cooling fluid within the pumping device.

[0006] However, the electrical implementation of these sensors in the cooling circuit, especially their electrical wiring for control and power supply, proves to be very complex and therefore costly. Ensuring reliable measurement of the respective measured value and protecting electrical components from the cooling fluid have also proven to be complex.

[0007] US 2015 / 093253 A1 discloses a pumping device for fresh water module systems and a method for detecting a fluid temperature of a medium pumped by the pumping device by measuring thermal radiation using a temperature sensor. Based on the detected thermal radiation, the fluid temperature of the pumped medium is determined using an externally performed calculation. This method requires the temperature sensor to be arranged outside the cooling fluid. However, this method and the required arrangement are also complex and may be unsuitable for automotive applications, since special requirements regarding accuracy, robustness, and reliability apply to automotive applications. A quick, reliable determination of the fluid temperature of a cooling fluid is often required.For example, it may be required to detect a change in the fluid temperature of the cooling fluid of 50 K within a maximum of 30 seconds, in particular a maximum of 15 seconds, in particular a maximum of 7 seconds. It is therefore an object of the present invention to provide an improved embodiment for a known pumping device in which at least one of the aforementioned disadvantages is partially or even completely eliminated. In particular, an object of the present invention is to provide a pumping device that is compact and robust and simultaneously enables reliable detection of at least one of the measured variables, in particular a fluid temperature of the cooling fluid.

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

[0009] A basic idea of ​​the invention is therefore to equip a pumping device for a motor vehicle, which can be arranged in a cooling circuit for circulating cooling fluid, with a sensor unit having at least one sensor, in particular with at least two sensors, for determining one or more measured variables characterizing the cooling fluid, in particular for determining two measured variables characterizing the cooling fluid. Since the cooling fluid to be circulated in the cooling circuit must necessarily be guided through a fluid channel provided in the pumping device in order to convey it, it is proposed to integrate said sensor unit directly into the pumping device. In this way, installation space can be saved. Furthermore, it is possible to use electrical components already installed in the pumping device for the electrical control or electrical power supply of the sensor unit, such asa printed circuit board with electrical / electronic components arranged thereon or a printed circuit board assembly (PCBA). Thus, an electrical voltage supply for supplying the electrical drive unit and / or other electrical / electronic components, in particular a control / regulation device, of the pumping device with electrical energy can be used at the same time to supply the sensor unit with electrical energy. Furthermore, a control / regulation device for controlling the electrical drive unit can be used at the same time to control the sensor unit and / or to process the respective measured variable detected by the sensor unit. This enables a considerable simplification of the design of the pumping device. This results in considerable cost advantages. The pumping device according to the invention can in principle also be suitable for applications whose subject matter is not or only partiallyat least not primarily the cooling of components that generate waste heat. The cooling fluid can therefore also be generally understood as a fluid or liquid.

[0010] Specifically, the pumping device according to the invention for conveying 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. The fluid channel can be designed, for example, as a water channel for water or cooling water as the cooling fluid, or as an oil channel for oil as the cooling fluid. Furthermore, the pumping device comprises a drive unit for driving the cooling fluid guided through the fluid channel.

[0011] Furthermore, the pumping device comprises an electrical sensor unit which comprises at least one sensor for determining at least one measured variable characterizing the cooling fluid, in particular a thermodynamic measured variable, such as a fluid temperature.

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

[0013] According to a second aspect of the invention, the at least one sensor of the sensor unit is arranged outside the fluid channel, alternatively or additionally to the arrangement according to the first aspect of the invention. The sensor is thermally coupled to the fluid channel. In particular, the sensor is thermally coupled to a fluid channel wall of the fluid channel. The fluid channel wall delimits a space of the fluid channel through which the cooling fluid can flow, in the region of the sensor. Generally speaking, the at least one sensor is preferably designed as a temperature sensor. As a result, the sensor can be used to determine the fluid temperature of the cooling fluid conveyed through the fluid channel. If thermally coupled to the fluid channel, the temperature sensor is heated by the thermally conductive coupling in accordance with the fluid temperature.

[0014] The fluid channel wall can be made, in particular predominantly, of metal. The fluid channel wall can contain metal and / or metal oxide, such as zinc oxide, silicon carbide or the like. The fluid channel wall is preferably made of stainless steel. The fluid channel wall is preferably non-magnetic or has only paramagnetic or diamagnetic properties. The fluid channel wall is preferably made of stainless steel. In some embodiments, the fluid channel wall can be made of plastic with a filler to ensure good thermal conductivity. Metal / metal oxide or the aforementioned materials, for example, can be considered as filler. Since metal-containing materials have good thermal conductivity, heat transfer from the cooling fluid to the fluid channel wall and heat transfer from the fluid channel wall to the temperature sensor can be improved.

[0015] This coupling via heat conduction has proven particularly effective compared to other types of heat transfer, such as thermal radiation or convection, in ensuring rapid and accurate determination of the fluid temperature while maintaining a robust design of the pumping device. 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, these are negligible for the heat transfer from the fluid channel wall to the temperature sensor.

[0016] In preferred embodiments, the sensor and a fluid channel wall of the fluid channel are spaced apart 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.

[0017] Preferably, the entire sensor unit is arranged in the housing of the pumping device outside the fluid channel, whereby the sensor unit is better protected.

[0018] According to an advantageous embodiment, the fluid channel wall has an external recess in which the sensor, in particular the sensor unit, is at least partially arranged. The sensor unit is preferably at least 50%, in particular at least 70%, in particular completely embedded in the recess. In particular, the recess has a depth of 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 external recess can be designed as an embossed portion of the fluid channel wall towards its inner side, in particular deep-drawn. To improve heat conduction, the sensor or the sensor unit is particularly preferably pressed against the fluid channel wall in the recess. The fluid channel wall can have a corresponding internal projection with the recess.The inner side of the fluid channel wall is the side of the fluid channel wall that defines the space through which the cooling fluid flows. Generally, the fluid channel wall is preferably constructed in one piece, in particular as a sheet metal component or injection-molded part.

[0019] By ensuring the best possible thermally conductive coupling between the sensor and the fluid channel or its fluid channel wall, the sensor can be arranged outside the fluid channel and still enable accurate determination of the fluid temperature. An arrangement outside the fluid channel in the housing of the pump device not only provides better protection for the sensor but also enables easier connection to other electrical / electronic components of the pump device, such as a control / regulation device. The invention also encompasses 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 or interaction with the fluid channel.

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

[0021] The fluid channel preferably has two channel regions arranged one after the other along a flow path of the cooling fluid in the fluid channel. The flow path describes the path of a fluid particle of the cooling fluid through the fluid channel via a location in the fluid channel closest to the sensor unit. One of the channel regions is designed to guide cooling fluid toward the sensor unit, and another of the channel regions is designed to guide cooling fluid guided toward the sensor unit away from the sensor unit. Thus, during operation of the pump device, cooling fluid is conveyed one after the other through both channel regions. Generally, the fluid channel regions are preferably aligned such that cooling fluid coming from one of the fluid channel regions flows against the fluid channel wall before entering the other fluid channel region. The fluid channel wall is preferably designed to redirect cooling fluid from one of the channel regions to enter the other of the channel regions, which improves the flow.Particularly preferably, the fluid channel is designed to deflect the cooling fluid along the flow path at the level of the sensor unit or of the 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 less than 160°, based on a respective orientation of the flow path immediately before and after the deflection, which creates advantageous flow conditions for heat transfer in the deflection region during operation of the pump device. The fluid channel thus preferably provides a flow path for cooling fluid from one of the channel regions against the fluid channel wall and from the fluid channel wall through the other of the channel regions. A preferably continuous flow improves the heat transfer from cooling fluid to the fluid channel or fluid channel wall, such that changes in the fluid temperature of the cooling fluid can be easily detected.

[0022] In a preferred embodiment of the pump device according to the invention, the drive unit of the pump device comprises a rotatable drive shaft on which a pump rotor for conveying the cooling fluid in the fluid channel is arranged in a rotationally fixed manner. Depending on the type of pump, the pump rotor can be designed, for example, as an impeller, gear, gerotor, eccentric or eccentric screw, rotary vane, or the like. The pump device further comprises an electric machine with a stator and a rotor for driving the drive shaft. The stator is arranged stationary relative to the housing, while the rotor is connected rotationally fixed to the drive shaft, so that a relative rotational movement can occur between the rotor and stator. The rotor is preferably designed as a permanent magnet. The drive shaft can be arranged rotatably on the housing or on another component of the pump device that is arranged stationary relative to the housing by means of suitable bearing elements.

[0023] According to a generally preferred embodiment, the pumping device has a wet area and a dry area that is sealed fluid-tight from the wet area. This prevents liquid, in particular the cooling fluid, from passing from the wet area into the dry area. The rotor of the electric machine is arranged in the wet area, and the stator of the electric machine is arranged in the dry area. Such so-called wet rotors are known to those skilled in the art. The fluid channel runs in the wet area of ​​the pumping device. Other components required for conveying the cooling fluid can each be arranged in the wet area. The temperature sensor, which is arranged outside the fluid channel and thermally coupled to the fluid channel, is arranged in the dry area.

[0024] The pump device preferably has a containment shell that fluid-tightly separates the dry and wet areas. The fluid channel wall is preferably formed at least in sections by the containment shell. The containment shell is preferably made of metal, with non-magnetic materials being preferred to avoid adverse interactions with permanent and / or electromagnetic components.

[0025] Generally, the fluid channel preferably extends in sections in the axial direction in a region radially between the stator and rotor, each relative to a rotational 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 pumping device is designed to be particularly integrated, and the cooling fluid can simultaneously serve to cool rotating parts of the pumping device. This can be further improved by having one of the channel regions run between the rotor and stator and / or by having the other channel region run through the rotor.

[0026] Furthermore, in an advantageous embodiment, the drive unit comprises a control / regulation device for controlling the electrical machine with stator and rotor. The control / regulation device is preferably arranged in the dry area of ​​the pumping device. The control / regulation device comprises an electrical circuit board on which at least one electrical / electronic component is arranged. These components can be, for example, sensors, capacitors, coils, resistors, switches, in particular semiconductor switches, and integrated circuits. Furthermore, in this embodiment, the sensor unit is electrically connected to the circuit board. In this way, the sensor unit can be controlled directly via the circuit board or with the aid of the electrical / electronic component arranged on the circuit board.Separate electrical wiring of the sensor unit to the outside is therefore not necessary; instead, the complete electrical control of the sensor unit can be carried out via the circuit board mentioned.

[0027] According to an advantageous development, the sensor unit can also be arranged on the circuit board. The sensor unit can thus be designed, for example, as an SMD component. The sensor unit and circuit board are then part of a printed circuit board assembly (PCBA). Thus, the sensor unit can be pre-assembled directly on the circuit board during the manufacture of the pumping device. Furthermore, this development eliminates the need for electrical connecting lines between the circuit board and the sensor unit, resulting in both space and cost advantages.

[0028] To ensure good heat conduction, the circuit board is preferably thermally connected to the fluid channel wall, in particular directly, by means of the thermally conductive layer. Generally, the fluid channel wall, thermally conductive layer, and circuit board are preferably stacked one above the other.

[0029] Electrical components of a printed circuit board arrangement are generally preferably arranged at least predominantly on one side of the printed circuit board in order to simplify production. The at least one sensor, in particular the sensor unit, is therefore preferably arranged on the side of the printed circuit board facing away from the fluid channel. This allows a space-saving embodiment and a simpler design of the printed circuit board arrangement. Preferably, more than 50%, in particular more than 85%, in particular all of all electrical / electronic components arranged on the printed circuit board are arranged on the side of the printed circuit board facing away from the fluid channel. By arranging as many components as possible on this one side facing away from the fluid channel, the printed circuit board can be arranged closer to the fluid channel.

[0030] When the pumping device is in operation, the circuit board can heat up due to electrical resistance, e.g. of electrical / electronic components and conductor tracks or integrated circuits on the circuit board. The circuit board or circuit board arrangement therefore represents a heat source. This self-heating can influence the determination of the measured variable, in particular the fluid temperature. According to an advantageous development, a further temperature sensor for detecting a circuit board temperature is therefore arranged on the circuit board. The sensor unit and the further temperature sensor are spaced apart and interact in such a way that, when determining the measured variable characterizing the cooling fluid, the influence of self-heating of the circuit board on the measured variable can be or is taken into account by comparing it with the circuit board temperature detected by the further temperature sensor.Advantageously, a thermally conductive coupling of the additional temperature sensor to the fluid channel is kept negligibly small. Particularly preferably, the additional temperature sensor is arranged radially adjacent to the fluid channel wall with no overlap relative to a rotational axis of the rotor. In particular, the circuit board is spaced from the fluid channel wall by a gap at the level of the additional temperature sensor. This gap ensures that a thermally conductive coupling of the circuit board to the fluid channel takes place outside the location where the additional temperature sensor is arranged.

[0031] In advantageous embodiments, the self-heating can be taken into account, in particular additionally, in a different way when evaluating a signal from the sensor of the sensor unit to determine the measured variable. According to a particularly preferred embodiment, a power consumption of the circuit board arrangement, i.e. of the circuit board and the electrical / electronic components arranged thereon, is recorded by a controller on the circuit board and a correlating differential value is subtracted from the signal of the at least one sensor. If the sensor is designed as a temperature sensor, the power consumption of the circuit board arrangement can thus be recorded by means of a controller and a correlating differential value can be subtracted as the differential temperature from the signal recorded by the temperature sensor. The accuracy of the temperature measurement is thus more approximated compared to when the sensor is arranged directly in the cooling fluid.

[0032] According to one development, the circuit board is pressed, in particular directly, against the fluid channel wall of the fluid channel. This improves heat conduction between the fluid channel and the temperature sensor arranged on the circuit board. In some embodiments, this makes it possible to dispense with a heat-conducting layer. According to one development, the at least one sensor of the sensor unit is arranged on the side of the circuit board facing the fluid channel, which improves the heat-conducting coupling of sensor and fluid channel. Furthermore, this ensures that the sensor or sensor unit can be arranged in the recess of the fluid channel wall, which also contributes to a compact design. In particular, the sensor or sensor unit is pressed against the fluid channel wall.

[0033] According to an advantageous development, the sensor unit can be electrically connected to the circuit board by means of at least one insulation displacement connection or at least one plug connection. This facilitates the removal of the sensor unit from the circuit board, should it become necessary.

[0034] According to an advantageous development, the control / regulation device can comprise an electrical power supply for supplying the electrical machine with electrical energy. In this development, the sensor unit for supplying the at least one sensor with electrical energy is electrically connected to this electrical power supply. Thus, the provision of a separate electrical connection between the sensor unit and such a power supply can be dispensed with. Instead, the sensor unit can be supplied with electrical energy via the electrical power supply of the control / regulation unit. This considerably simplifies the electrical wiring of the sensor unit, which also results in significant cost advantages.

[0035] According to an advantageous development, the control device comprises a communication unit for communicating with an external fieldbus, in particular with a LIN or CAN bus of a motor vehicle. In this development, the sensor unit for reading or controlling the at least one sensor is electrically orZand data-transmittingly connected to the controller andZor the communication unit. This enables flexible control or flexible reading of the sensor unit from outside via said fieldbus, without the need for a separate communication unit.

[0036] Rather, to control or read the sensor unit, the

[0037] Communication unit of the control Z regulation device can be used.

[0038] According to a preferred embodiment, the temperature measured by a sensor and a phase current of the electric machine determined by the control / regulation device, and in particular a speed of the pump rotor, are to be processed by means of a correlation of pressure, temperature and phase current, and in particular speed, stored in the control / regulation device, in particular to be processed in the control / regulation device, in order to calculate a pressure of the cooling fluid. Particularly preferably, the pump device is further configured to transmit data relating to the calculated pressure via the control / regulation device, in particular the communication unit for communicating with the external fieldbus. This makes it possible to dispense with pressure sensors in the fluid channel and nevertheless to at least roughly determine a pressure prevailing in the pump device.

[0039] In a preferred embodiment, the pumping device is designed to process a temperature measured by the temperature sensor as at least one sensor and a rotational speed of the pump rotor, and in particular a phase current of the electric machine determined by the control / regulation device, by means of a correlation of pressure, temperature and phase current, and in particular rotational speed, stored in the control / regulation device, in particular to process said correlation in the control / regulation device, in order to calculate a mass flow and / or volume flow of the cooling fluid. Particularly preferably, the pumping device is further configured to transmit data relating to the calculated mass flow or volume flow via the control / regulation device, in particular the communication unit for communicating with an external fieldbus.This makes it possible to dispense with mass flow sensors in the fluid channel and still determine a mass flow of the cooling fluid in the fluid channel at least roughly. However, the invention also includes embodiments in which pressure or mass / volume flow is recorded directly. In a preferred embodiment, the sensor unit can have at least two of the sensors explained below. Such a sensor can be a pressure sensor for determining the fluid pressure of the cooling fluid guided through the fluid channel. This makes it possible to determine exactly at what pressure the cooling fluid is pumped by the pump device. Another sensor in the sensor unit can be a temperature sensor for determining the cooling fluid temperature of the cooling fluid guided through the fluid channel. This makes it possible to determine the fluid temperature of the cooling fluid guided through the fluid channel very precisely.This proves to be particularly important when the cooling fluid is intended to absorb waste heat from the components to be cooled. In this embodiment, a further sensor of the sensor unit can be a mass flow sensor for determining the mass flow of cooling fluid through the fluid channel. In this way, the current flow rate of the cooling fluid pumped by the pump device can be precisely determined. In this embodiment, a further sensor of the sensor unit can comprise an electrical conductivity sensor for determining the electrical conductivity of the cooling fluid guided through the fluid channel. In this way, the electrical conductivity of the cooling fluid can also be precisely determined. Precise knowledge of the electrical conductivity of the cooling fluid can prove advantageous if the fluid channel is bordered by metal components, since in this case the cooling fluid with excessive electrical conductivity could cause an electrical short circuit.However, it is also conceivable to use at least one further sensor to determine another measurement parameter in combination with at least one of the sensors presented above.

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

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

[0042] In this refinement, the sensor unit is preferably arranged in an axial extension of the cavity in the fluid channel. This ensures reliable flow in the area of ​​the sensor unit.

[0043] In an advantageous embodiment, the rotor has an axial passage to the pump rotor. In this embodiment, the cooling channel runs through this passage. The flow path of the cooling fluid can thus run through the rotor. Particularly preferably, one of the two channel regions runs through the passage of the rotor to the pump rotor. Preferably, the passage is formed radially between a holding section and a magnetic section radially spaced from the holding section. The holding section and magnetic section are rigidly connected to one another, in particular by overmolding with a plastic. The rotor is fastened to the drive shaft by means of the holding section. The rotor is designed to be permanently magnetic, at least in the magnetic section, in particular such that at least one permanent magnet is arranged in the magnetic section. In the further development, the rotor thus forms part of the fluid channel between the magnetic section and the holding section.This enables better integration of the cooling channel and at the same time allows effective cooling of the rotor using cooling fluid.

[0044] The inventors have found that a high flow velocity of the cooling fluid improves heat transfer to the temperature sensor. In order to create favorable flow conditions, the pumping device can have a conveying geometry along the fluid channel, which enables a higher flow velocity. The conveying geometry interacts effectively with the cooling fluid to convey cooling fluid. According to one embodiment, at least one conveying geometry is formed in the hollow shaft. When the hollow shaft rotates, the conveying geometry interacts with the cooling fluid in such a way that cooling fluid is conveyed through the hollow shaft. Accordingly, in advantageous embodiments, the rotor can have at least one conveying geometry, particularly in the passage. When the rotor rotates, the conveying geometry interacts with the cooling fluid in such a way that cooling fluid is conveyed through the rotor and / or past the rotor.Such conveying geometries are also conceivable in other areas, in particular in the first and / or second channel area, of the fluid channel.

[0045] According to an advantageous embodiment, a sealing device is arranged axially between the pump rotor and the rotor for sealingly connecting the rotor to the housing. The sealing device is preferably designed as a labyrinth seal. The sealing device provides a sealing gap between the rotor and the housing. The sealing gap ensures the sealing connection and allows the intended relative movement of the rotor relative to the housing for driving the drive shaft. For this purpose, the sealing device has a first sealing part that is rigidly, in particular integrally, connected to the rotor and a second sealing part that is rigidly, in particular integrally, connected to the housing. The sealing gap is formed between the sealing parts. The sealing device is preferably arranged on both sides of the sealing device in opposite directions so that cooling fluid can flow past.In particular, the sealing device separates the two channel regions from one another. The sealing gap preferably has a gap width of a maximum of 2 mm, in particular a maximum of 1 mm, and in particular at least 0.2 mm. Since only a negligible proportion of cooling fluid can penetrate through the sealing gap, sufficient sealing is ensured. In one embodiment, the sealing device is designed to delimit the fluid channel in such a way that cooling fluid guided in the direction of the sensor unit passes past the sealing device to the pump rotor. In one embodiment, the sealing device is designed to delimit the fluid channel in such a way that cooling fluid is guided past the sealing device in the direction of the sensor unit. As a result, cooling fluid flowing through the rotor is reliably guided to the pump rotor without significantly mixing with cooling fluid from other channel regions.

[0046] Particularly preferably, the housing can be designed in at least two parts, preferably three parts, with a main housing body in which the drive unit is arranged, and with at least one, preferably two, housing cover(s). In this variant, the at least one housing cover is detachably fastened to the housing body, preferably by means of at least one screw connection. Furthermore, in this variant, the sensor unit, and preferably also the circuit board, is firmly connected to a housing cover. Thus, the sensor unit can be mounted on the pump device during the assembly of the housing cover on the main housing body, and the sensor unit can also be pre-assembled 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 cooling fluid, in particular water or cooling water, and a pumping device according to the invention arranged in the cooling circuit for conveying the cooling fluid in the cooling circuit. The above-explained advantages of the pumping device according to the invention are therefore transferred to the cooling device according to the invention.

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

[0049] The invention also relates to a motor vehicle with a cooling device according to the invention as explained above. The above-explained advantages of the pumping device according to the invention are therefore transferred to the motor vehicle according to the invention. According to one embodiment, this comprises a waste heat-generating fuel cell system that is thermally coupled to the cooling device, so that the generated waste heat can be transferred to the cooling fluid circulating in the cooling circuit.

[0050] The invention also relates to a method for determining a measurand, in particular a thermodynamic measurand, in particular a fluid temperature, which characterizes a cooling fluid in a pumping device according to the invention. In the method, the cooling fluid is guided in a fluid channel towards a sensor unit. Heat or thermal energy is transferred from the cooling fluid guided towards the sensor unit to the sensor unit by flowing against the fluid channel and via a heat-conducting coupling between the fluid channel and the sensor unit. A sensor in the sensor unit detects the thermal energy transferred to the sensor unit by measuring the temperature, with the sensor unit preferably determining the measurand. The cooling fluid guided towards the sensor unit is guided away from the sensor unit.

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

[0052] The method may have features described above in connection with the pumping device, motor vehicle, or cooling device. Further important features and advantages of the invention emerge from the subclaims, the drawings, and the associated description of the figures with reference to the drawings.

[0053] It is understood that the features mentioned above and those to be explained below can be used not only in the combination specified but also in other combinations or on their own, without departing from the scope of the present invention.

[0054] Preferred embodiments of the invention are illustrated in the figures and are explained in more detail in the following description, wherein the same reference numerals refer to the same or similar or functionally identical components.

[0055] It shows

[0056] Fig. 1: an example of a pumping device according to the first aspect of the invention in a sectional view;

[0057] Fig. 2: an exemplary embodiment of a pumping device according to the second aspect of the invention in a sectional view.

[0058] Figure 1 shows an example of a pumping device 1 according to the invention designed as a water pump in a sectional view. The pumping device 1 serves to convey cooling fluid W, in particular water, in particular cooling water. The pumping device 1 comprises a housing 2, in which a fluid channel 3 through which the cooling fluid W to be conveyed can flow is arranged. Furthermore, the pumping device 1 comprises an electric drive unit 4, which in the example according to Figure 1 is partially arranged in the fluid channel 3, for driving the cooling fluid W guided through the fluid channel 3. The drive unit 4 of the pumping device 1 has a rotatable drive shaft 7 arranged in the fluid channel 3, on which drive shaft 7 a pump rotor 8 designed as an impeller is arranged in a rotationally fixed manner for conveying water as the cooling fluid W in the fluid channel 3.

[0059] In addition, the pumping device 1 of the embodiment according to Figure 1 comprises an electrical sensor unit 5 arranged at least partially in the fluid channel 3, which in the example comprises four sensors 6a, 6b, 6c, 6d, each for determining a measured variable characterizing the cooling fluid W. A first sensor 6a of the four sensors 6a-6d in the example is a pressure sensor for determining the fluid pressure of the cooling fluid W guided through the fluid channel 3. This makes it possible to precisely determine the pressure at which the cooling fluid W is conveyed by the pumping device. A second sensor 6b of the four sensors 6a-6d of the sensor unit 5 is a temperature sensor for determining the fluid temperature of the cooling fluid W guided through the fluid channel 3. This makes it possible to very precisely determine the fluid temperature of the cooling fluid W guided through the fluid channel 3. This proves to be particularly important if the cooling fluid W is to function as cooling water and thus absorb waste heat from the components to be cooled.A third sensor 6c of the four sensors 6a-6d of the sensor unit 5 is a mass flow sensor for determining the mass flow of cooling fluid W through the fluid channel 3. In this way, the instantaneous flow rate of the cooling fluid pumped by the pump device can be precisely determined. A fourth sensor 6d of the four sensors 6a-6d of the sensor unit 5 is an electrical conductivity sensor for determining the electrical conductivity of the cooling fluid W conveyed through the fluid channel 3. This also allows the electrical conductivity of the cooling fluid W to be precisely determined. Precise knowledge of the electrical conductivity of the cooling fluid W can prove particularly important if the fluid channel 3 is delimited by metal components, since in this case the cooling fluid W could cause an electrical short circuit if the electrical conductivity is too high.

[0060] The sensor unit 5 can expediently be equipped with a sensor housing 17 in or on which the four sensors 6a-6d are arranged. Furthermore, in this development, the four sensors 6a-6d and the sensor housing 17 are designed as a structural unit. The drive unit 4 comprises an electric machine 9 with a stator 10 and a rotor 11 for driving the drive shaft 7. The drive shaft 7 can, as shown in Figure 1, be designed as a hollow shaft 18 with a hollow-cylindrical geometry, which surrounds a cylindrical cavity 19 on the circumferential side and is open axially on both sides. The cavity 19 forms part of the fluid channel 3. The sensor unit 5 with the sensors 6a-6d protrudes into the fluid channel 3 in the region of an axial extension 20 of the cavity 19.The stator 10 is arranged stationary relative to the housing 2, while the rotor 11 is connected in a rotationally fixed manner to the drive shaft 7, so that during operation of the pumping device 1, a relative rotational movement occurs between the rotor 11 and the stator 10. The rotational movement of the rotor 11 occurs about a rotational axis D, which is identical to a central longitudinal axis M of the drive shaft 7. The central longitudinal axis M extends along an axial direction A. The drive shaft 7 can be arranged rotatably on the housing 2 or on another component (not shown) of the pumping device 1 that is stationary relative to the housing 2 by means of suitable bearing elements (not shown).

[0061] As illustrated in Figure 1, the rotor 11 can be arranged in the fluid channel 3. The stator 10 can delimit the fluid channel 3 in that section of the fluid channel 3 in which the rotor 11 is arranged. Thus, the cooling fluid W flowing through the fluid channel 3 can cool both the stator 10 and the rotor 11.

[0062] Furthermore, the drive unit 4 comprises a control / regulation device 12 for controlling the electric machine 9. The control / regulation device 12 comprises an electrical circuit board 13 on which electrical and electronic components are arranged. These components can be, for example, capacitors, coils, resistors, switches, in particular semiconductor switches, as well as 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 with the aid of the electrical / electronic components arranged on the circuit board 13. Separate wiring of the sensor unit 5 to the outside is therefore not necessary; rather, the entire electrical application of the sensor unit can be carried out via the circuit board 13.In the example scenario, the sensor unit 5 is arranged directly on the circuit board 13. This eliminates the need for electrical connecting lines between the circuit board and the sensor unit. The sensor unit 5 can optionally be electrically connected to the circuit board 13 using a suitable insulation displacement connection or suitable plug-in connections, which simplifies any necessary removal of the sensor unit 5 from the circuit board 13.

[0063] In the example, the control / regulation device 12 comprises an electrical power supply 14 for supplying the electrical machine 9 with electrical energy. The sensor unit 5 for supplying the at least one sensor 6 with electrical energy is electrically connected to this electrical power supply 14. Thus, the provision of an electrical power supply 14 and the provision of a separate electrical connection of the sensor unit 5 to such a power supply can be dispensed with. Instead, the sensor unit 5 can be supplied with electrical energy via the electrical power supply of the control / regulation unit 12. This significantly simplifies the electrical wiring of the electrical sensor unit 5, which also results in significant cost advantages.Furthermore, the control / regulation device 12 comprises a communication unit 15 for communicating with an external fieldbus (not shown), in particular a LIN or CAN bus of a motor vehicle. The sensor unit 5 for controlling the four sensors 6a-6d is connected to this communication unit 15 electrically and also for data transmission. This enables flexible control of the sensor unit 5 from outside, in particular via said fieldbus, without the need for a separate communication unit. Instead, the communication unit 15 of the control / regulation device 12 can be used to control the sensor unit 5.

[0064] In the example of Figure 1, the housing 2 is constructed in three parts, comprising a main housing body 2a, in which the drive unit 4 is arranged, and two opposing housing covers 2b, 2c. As shown, the main housing body 2a can be sandwiched between the two housing covers 2b, 2c. The two housing covers 2b, 2c are each releasably attached to the main housing body 2a by means of screw connections 16. The sensor unit 5 and the circuit board 13 are each firmly connected to a first housing cover 2b of the two housing covers 2b, 2c. Thus, the sensor unit 5 can be pre-assembled mounted on the first housing cover 2b during the assembly of the pumping device 1. This facilitates the assembly of the pumping device 1.

[0065] Figure 2 shows an exemplary embodiment of a pumping device 1 according to the second aspect of the invention in a schematic longitudinal section. Since the embodiment of Figure 2 corresponds to the embodiment according to Figure 1 with regard to many features, reference is made to the above description with regard to corresponding features and is supplemented below. The pumping device 1 in Figure 2 serves to pump oil as cooling fluid W. The pumping device 1 has a housing 2 with housing covers 2a, 2c and a housing main body 2b, in which a fluid channel 3 with a plurality of channel regions 3a, 3b runs between a stator 10 and a rotor 11 of an electrical machine 9 and through an axial passage of the rotor 11 to a pump rotor 8. The pump rotor 8 and rotor 11 are connected in a rotationally fixed manner by a drive shaft 7. The pumping device 1 is divided into a wet region and a dry region by a containment shell 23.The stator 10 and electrical / electronic components are located in the dry area. The fluid channel 3 runs and the rotor 11 is located in the wet area.

[0066] The passage of the rotor 8 is formed radially between a holding section 111 and a magnetic section 112. The holding section 111 serves to attach the rotor to the drive shaft 7. The magnetic section 112 is permanently magnetic and contains permanent magnets.

[0067] A sealing device 21 designed as a labyrinth seal is arranged axially between the pump rotor 8 and the rotor 11 to seal an area between the rotor 11 and the housing 2 through which cooling fluid W would otherwise flow. The sealing device 21 provides a sealing gap 22 through which only a negligible proportion of cooling fluid W can penetrate. As a result, cooling fluid W flowing through the rotor 11 is reliably guided to the pump rotor 8 without significantly mixing with cooling fluid W from other channel areas.

[0068] Unlike the exemplary embodiment of Figure 1, the drive shaft 7 is designed as a solid shaft. Instead of the cavity of a hollow shaft as part of the fluid channel, the rotor 11 is provided with the axial passage between the holding section 111 and a magnet section 112, through which cooling fluid W can flow. The passage is part of the fluid channel 3. However, embodiments with a hollow shaft are also within the scope of the invention, so that the fluid channel, in particular in addition to the passage through the rotor 11, can run through the hollow shaft to the pump rotor 8.

[0069] In the embodiment shown in Figure 2, the pumping device is designed as a gerotor pump. The pump rotor 8 is thus designed as a gerotor, in particular a multi-stage gerotor. The individual gerotor stages are not shown in the schematic representation. Multi-stage gerotor pumps are known and are described, for example, in German patent application DE 10 2021 214 256 A1 or international patent application WO 00 / 42321 A1.

[0070] The flow path of the cooling fluid W through a channel region 3a between rotor 11 and stator 10 is indicated by arrows. The pumping device is designed to be essentially rotationally symmetrical in the region of rotor 11 and stator 10, so that cooling fluid can naturally flow through rotor 11 on both sides of the rotational axis D shown. The point drawn in the region of pump rotor 8 illustrates the conveyance of cooling fluid W in pump rotor 8 perpendicular to the rotational axis of pump rotor 8 from a suction side to a pressure side. Cooling fluid in the pump rotor is compressed from the suction side to the pressure side. The invention generally also includes embodiments in which the flow path of the cooling fluid is reversed, i.e. the suction and pressure sides are swapped. In such embodiments, the cooling fluid flows from the pressure side through rotor 11 or drive shaft 7.

[0071] The containment shell 23 forms a fluid channel wall 3c at its bottom. The cooling fluid W flows along the flow path against the fluid channel wall 3c when the cooling fluid W is conveyed through the fluid channel 3. This ensures effective heat transfer from the cooling fluid to the fluid channel 3 or its fluid channel wall 3c.

[0072] The pumping device 1 further comprises a sensor unit 5. This is arranged on a side of a circuit board 13 of a control / regulation device 12 of the pumping device 1 facing away from the cooling channel 3. The sensor unit 5 has a sensor 6 designed as a temperature sensor 61. A further temperature sensor 62 is arranged at a distance therefrom on the circuit board 13. The further temperature sensor 62 is preferably arranged such that a heat flow transmitted by thermal conduction from the fluid channel 3 to the further temperature sensor 62 amounts to a maximum of 30% of a heat flow from the fluid channel 3 to the sensor 6 of the sensor unit. As a result, the further temperature sensor 62 predominantly detects self-heating of the circuit board 13 that correlates with the drawn electrical power. The temperature sensor 61 of the sensor unit 5, on the other hand, serves to determine the fluid temperature of the cooling fluid W and is, for this purpose, thermally conductively coupled to the fluid channel 5.

[0073] A gap filler is arranged as a thermally conductive layer 24 between the circuit board 13 and the fluid channel 3 or the gap pot 23 or the fluid channel wall 3c, in contact with the fluid channel 3 and the circuit board 13. This thermally conductive layer 24 ensures good thermal conduction between the fluid channel and the circuit board 13, with the sensor 6, as a temperature sensor, being thermally coupled to the fluid channel 3 via the circuit board 13 and the thermally conductive layer 24.

[0074] The heat conducting layer 24 extends over the entire can base.

[0075] The circuit board 13 extends radially beyond the fluid channel wall 3c and the thermally conductive layer 24. The fluid channel wall 3c, the thermally conductive layer 24, and the circuit board 13 are thermally conductively connected over the entire area in which they overlap.

[0076] The quality of heat transfer from the cooling fluid to the fluid channel 5 or the sensor 6 is significantly improved if it is ensured that cooling fluid W flows continuously against the fluid channel wall 3c. Sensor 6 or sensor unit 5 and fluid channel 3 are therefore coordinated with regard to their arrangement. Cooling fluid W guided through channel region 3a towards the sensor unit 5 flows against the fluid channel wall 3c, transferring heat to the fluid channel wall 3c and is deflected by the latter in such a way that the cooling fluid W is guided away from the sensor unit 5 or sensor 6 through channel region 3b. The sensor 6 is arranged at the level of the point at which the deflection occurs, so that the shortest possible path for heat transfer from the fluid channel 3 to sensor 6 by heat conduction is provided.

[0077] List of reference symbols

[0078] 1 pumping device

[0079] 2 housings

[0080] 2a Housing main body

[0081] 2b, 2c housing cover

[0082] 3 Fluid channel

[0083] 3a, 3b canal area

[0084] 3c Fluid channel wall

[0085] 4 Drive unit

[0086] 5 Sensor unit

[0087] 6 Sensor

[0088] 6a first sensor 6b second sensor

[0089] 6c third sensor

[0090] 6d fourth sensor

[0091] 7 Drive shaft

[0092] 8 Pump rotor

[0093] 9 electric machine

[0094] 10 Stator

[0095] rotor

[0096] 12 Control Z control device

[0097] 13 Circuit board

[0098] 14 Power supply

[0099] 15 Communication unit

[0100] 16 screw connection

[0101] 17 Sensor housing

[0102] 18 hollow shaft

[0103] 19 Cavity

[0104] 20 axial extension

[0105] 21 Sealing device

[0106] 22 Sealing gap

[0107] 23 containment shell

[0108] 24 Thermally conductive layer

[0109] 61 Temperature sensor

[0110] 62 temperature sensors

[0111] holding section

[0112] 112 Magnet section

[0113] A axial direction

[0114] D axis of rotation

[0115] M central longitudinal axis

[0116] W Cooling fluid

Claims

Patent claims Pump device (1) for a motor vehicle, in particular for a cooling device of a fuel cell system, and for conveying cooling fluid (W), in particular cooling water and / or oil, - with a housing (2) in which a fluid channel (3) through which the cooling fluid (W) to be conveyed can flow is arranged, - with a drive unit (4) for driving the cooling fluid (W) guided through the fluid channel (3), - with 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 a fluid temperature, wherein the sensor unit (5) is arranged at least partially in the fluid channel (3), preferably protruding into the fluid channel (3), and / or the at least one sensor (6) of the sensor unit (5) is designed as a temperature sensor (61), is arranged outside the fluid channel (3), and is thermally coupled to the fluid channel (3), in particular to a fluid channel wall (3c). Pumping device (1) according to claim 1, wherein - the drive unit (4) comprises a rotatable drive shaft (7) with a pump rotor (8), in particular an impeller, for conveying the cooling fluid (W) in the fluid channel (3) and an electric machine (9) with a stator (10) and with a rotor (11) for driving the drive shaft (7) with the pump rotor (8), in particular the impeller, - the drive unit (4) further comprises a control device (12) for controlling the electrical machine (9), wherein the control / Control device (12) has an electrical 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). Pumping device (1) according to claim 2, wherein the sensor unit (5) is arranged on the circuit board (13), wherein in particular the temperature sensor (61) is thermally conductively coupled to the fluid channel (3) via the circuit board (13). Pumping device (1) according to one of claims 2 to 3, wherein the pumping device (1) has a containment shell (23) which fluid-tightly separates a dry region, in which the stator (10) of the electrical machine (9) is arranged, from a wet region, in which the rotor (11) of the electrical machine (9) is arranged and in which the fluid channel (3) runs, wherein in particular the fluid channel wall (31) is formed at least in sections by the containment shell (23).Pump device (1) according to one of claims 1 to 4, wherein the fluid channel (3) has two channel regions (3a, 3b) arranged one after the other along a flow path of the cooling fluid (W), of which one channel region (3a, 3b) is designed to guide cooling fluid in the direction of the sensor unit (5) and the other channel region (3a, 3b) is designed to guide cooling fluid (W) guided in the direction of the sensor unit (5) away from the sensor unit (5), wherein in particular the fluid channel (3) is designed to divert cooling fluid (W) along the flow path at the level of the at least one sensor (6) of the sensor unit (5) from one of the channel regions (3a, 3b) to enter the other of the channel regions (3a, 3b).Pump device (1) according to one of the preceding claims 2 to 5, wherein the rotor (11) has an axial passage 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 the sealing connection of the rotor (11) and the housing (2), wherein the sealing device (21) has a sealing gap between. Rotor and housing, which is formed between a first sealing part connected to the rotor and a second sealing part connected to the housing. Pumping device (1) according to one of claims 2 to 6, wherein a further temperature sensor (62) for detecting a circuit board temperature is arranged on the circuit board (13), wherein the sensor unit (5) and the further temperature sensor (62) are spaced apart and interact such that, when determining the measured variable characterizing the cooling fluid (W), in particular the fluid temperature, an influence of self-heating of the circuit board on the measured variable can be taken into account by comparison with the circuit board temperature detected by the further temperature sensor. Pumping device according to one of claims 2 to 7, wherein - the control device (12) comprises an electrical voltage supply (14) for supplying the electrical machine (9) with electrical energy, - the sensor unit (12) for supplying the at least one sensor (6) with electrical energy is electrically connected to this electrical power supply (14). Pumping device (1) according to one of claims 2 to 8, wherein the control device (12) comprises a communication unit (15) for communicating with an external field bus, in particular a LIN or CAN bus of a motor vehicle, the sensor unit (5) for controlling the at least one sensor (6) is electrically or data-transmittingly connected to this communication unit (15). Pumping device (1) according to 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 the temperature sensor, for determining the fluid temperature of the cooling fluid (W) guided through the fluid channel (3), a mass flow sensor for determining the mass flow of cooling fluid (W) through the fluid channel (3), and / or a conductivity sensor for determining the electrical conductivity of the cooling fluid (W) guided through the fluid channel.

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

13. Water pump according to one of the preceding claims, wherein the housing (2) is formed in at least two parts, preferably three parts, with a housing main body (2a), in which the drive unit (4) is arranged, and at least one, preferably two, housing cover(s) (2b, 2c), which is / are detachably fastened to the housing main body (2a), preferably by means of at least one screw connection (16), the sensor unit (5), preferably also the circuit board (13), is firmly connected to a housing cover (2b). . Motor vehicle, comprising - a cooling device with a cooling circuit for circulating cooling fluid (W), - a pumping device (1) arranged in the cooling circuit according to one of the preceding claims for conveying the cooling fluid (W) in the cooling circuit, wherein the motor vehicle further comprises a drive train with waste heat-generating components that are thermally coupled to the cooling circuit for transferring generated waste heat to the cooling fluid circulating in the cooling circuit. Method for determining a measured variable, in particular a fluid temperature, that characterizes a cooling fluid (W) in a pumping device according to one of the preceding claims 1 to 13, wherein - the cooling fluid (W) is guided in a fluid channel (3) towards a sensor unit (5), - heat of the cooling fluid (W) guided towards the sensor unit (5) is transferred to the sensor unit (5) by flowing into the fluid channel (3) and via heat-conducting coupling of the fluid channel (3) and the sensor unit (5), - a 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 - the cooling fluid (W) guided towards the sensor unit (5) is guided away from the sensor unit (5), wherein in particular - the cooling fluid (W) is deflected along a flow path of the cooling fluid (W) at the level of the at least one sensor (6) of the sensor unit (5) from one channel region (3a, 3b) of the fluid channel (5) to enter another channel region (3a, 3b) of the fluid channel (5).

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