DE102023111437A1 - Sensor with housing and measuring cell, vehicle component with a sensor holder into which the sensor is inserted, test device and test method for testing the sensor - Google Patents

Abstract

The invention relates to a sensor (10) with a measuring cell (12) and a housing (14) which encloses the measuring cell (12) and extends from a connection side (16) to a measuring side (18) facing away from the connection side. According to the invention, the housing (12) has a dedicated test channel which is open towards the connection side and extends from the measuring cell (12) to an opening on the connection side.

Description

The present invention relates to a sensor with a measuring cell and a housing that encloses the measuring cell and extends from a connection side to a measuring side facing away from the connection side. The housing serves to protect the measuring cell. The present invention also relates to a vehicle component, for example a manual transmission, with a sensor whose measuring cell is enclosed by a housing, as well as vehicles with a corresponding vehicle component. Vehicles with a vehicle component that has a sensor whose measuring cell is enclosed by a housing are in particular motor vehicles such as passenger cars, trucks or tractors, but also moving machines such as cranes, forklifts or excavators. The present invention also relates to a testing device for a sensor whose measuring cell is enclosed by a housing.

Sensors are used in a variety of forms and sometimes under harsh environmental conditions. Applications in motor vehicles, for example in the area of the engine, transmission or hydraulic or pneumatic systems, are often associated with harsh environmental conditions.

It is known to embed measuring cells in a typically injection-molded plastic housing in order to protect the measuring cells from environmental influences. A corresponding sensor then has a plastic housing that encloses the measuring cell, i.e. protects it. At the same time, such a housing has connections for the measuring cell on one connection side.

Nevertheless, such sensors can fail if, for example, oil gets into the measuring cell. This can happen, for example, if the sensor is exposed to gear oil in harsh environments such as an engine with a gearbox and the housing is not sealed or not sealed for a long time despite all measures. The penetration can be caused by fine cracks that could already occur when the measuring cell is overmolded - i.e. when the housing is injection molded.

Since a sensor failure, inspection and, if necessary, replacement, especially at critical locations in motor vehicles and in harsh environments, involves considerable effort and a longer outage of the vehicle -- in the worst case, also with damage and corresponding maintenance -- sensors are tested before installation.

The test method used for this is naturally a leak test between the measuring side and the connection side. The housing is naturally tested for air that has, for example, entered the measuring cell from the connection side through an undesirable crack, i.e. that also entered the measuring side from the connection side. This applies to air that has entered through natural leakage paths, for example around connection lines for the measuring cell. Such natural leakage paths typically arise when the connection lines are overmolded.

Despite the usual tests, failures of tested sensors are repeatedly observed, which are ultimately due to cracks in the sensor housing.

This is where the invention comes in, the object of which is to provide an improved sensor.

With regard to the sensor, the object is achieved according to a first aspect of the invention by a sensor according to claim 1.

Accordingly, a sensor with a housing and measuring cell is provided, in which the housing encloses the measuring cell and extends from a connection side to a measuring side facing away from the connection side. According to the invention, the housing has a dedicated and defined test channel that is open towards the connection side and extends from the measuring cell to an opening on the connection side.

The invention includes the finding that when overmolding the measuring cell, a perfect seal between the measuring side and the connection side of the housing can be achieved even if the housing has a crack in the area of the measuring cell.

In other words, a perfect seal between the measuring side and the connection side of the housing for the usual sensors and tests mentioned above would prevent a crack from the measuring cell to the measuring side from being detected when testing the usual sensors. If, for example, the usual natural leakage path around the connection lines did not actually remain, the crack would not be detected. Then there is still a risk that the sensor will fail in use, even though the sensor has passed the test.

Therefore, the idea is to introduce the dedicated and defined test channel into the housing of the sensor to enable a reliable leakage test in case a crack Interior of the housing connects to the environment at an undesirable location on the measuring side of the housing.

The inventive concept relating to the sensor and the testing method has the advantage that not only a crack from the measuring cell to the connection side but also a crack from the measuring cell to the measuring side can be detected when testing the sensors according to the invention. The probability of failure of this type and of sensors tested using the inventive method and found to be good is significantly reduced.

Further developments of the invention are specified in the dependent claims, which further develop the concept of the invention with regard to advantageous features within the scope of the task and with regard to further advantages.

According to a preferred development, the housing has a circumferential seal on its outside, which is arranged in the longitudinal direction of the housing between the measuring side and the connection side and is designed to seal against an inner wall of a sensor holder. The housing is - provided there are no undesirable cracks - completely sealed from the housing end on the measuring side to the seal. The measuring cell is preferably arranged on a side of the seal in the housing that faces away from the connection side - i.e. in the area of the measuring side. This arrangement has the advantage that the measuring cell can be positioned as close as possible to a measuring location if the measuring location is in the area of environmental conditions that could be detrimental to the measuring cell.

Examples of this are a sensor with a measuring cell in the form of a Hall probe, which is used to detect the position of a moving component (e.g. an axially displaceable shaft with a gear) inside a manual transmission, or a GMR sensor (a sensor based on the giant magnetoresistance effect) for detecting a speed of a gear, the teeth of which modulate the signal of the GMR sensor; in general, a speed sensor has a measuring cell designed to detect the speed of a gear or other similar rotating component.

The seal preferably encloses the housing in a circular shape. This allows the sensor to be inserted into a hollow cylindrical sensor holder and results in a reliable seal between the inner wall of the sensor holder and the sensor housing. The circular shape of the seal has two advantages: It enables a particularly reliable seal and allows the sensor to be inserted in any orientation in relation to the circumferential direction.

Preferably, the measuring cell is connected to at least one connecting line that extends outside the test channel from the measuring cell to the connection side of the housing and possibly beyond. The fact that the connecting line or lines run outside the test channel ensures that the test channel remains open in a defined manner throughout and allows reliable testing.

On the connection side, the housing preferably has at least one connection contact, which is connected to the measuring cell via the at least one connection line. The at least one connection line is preferably an electrical line and the measuring cell is preferably designed to output electrical measurement signals.

The housing is preferably an injection-molded plastic housing. This has the advantage that the measuring cell can usually be provided with a protective housing in a reliable and simple manner.

Preferably, the housing has a circumferential groove on its outside for receiving a seal, which is arranged in the longitudinal direction of the housing between the measuring side and the connection side. In this case, an O-ring can be used as a seal, which can be inserted into the groove. Alternatively, the seal can also be molded onto the housing (e.g. by means of co-molding, overmolding or co-injection molding).

The sensor is preferably a position sensor, particularly preferably a speed sensor. Accordingly, the measuring cell is preferably designed to detect the position of a moving part along a path, in particular to detect the speed of a rotating component. The examples mentioned above and the examples mentioned in the figures are intended to be illustrative and not restrictive. In principle, the invention is not restricted to a specific, but nevertheless preferred, measuring function and/or type of measurement.

However, a measuring cell that is preferably designed as a Hall probe (e.g. for a speed sensor) or as a capacitive measuring cell for a capacitive sensor (e.g. as a displacement sensor) has proven to be particularly advantageous for the above-mentioned measuring functions. This has the advantage that the measuring cell functions without contact and thus the functionality of the measuring cell is not impaired by the plastic housing.

A further aspect relates to a test method for testing a sensor of the type according to the invention.

• - der Sensor wird in eine Sensoraufnahme dichtend eingesetzt,
• - eine Druckdifferenz wird zwischen der Messseite und der Anschlussseite des Sensors in der Sensoraufnahme hergestellt und
• - ein Druckabfall wird als Veränderung der Druckdifferenz zwischen der Messseite und der Anschlussseite des Sensors in der Sensoraufnahme erfasst.

According to a first variant of the test procedure, the procedure comprises the following steps:

• - the sensor is inserted into a sensor holder in a sealing manner,
• - a pressure difference is created between the measuring side and the connection side of the sensor in the sensor holder and
• - a pressure drop is detected as a change in the pressure difference between the measuring side and the connection side of the sensor in the sensor holder.

• - der Sensor wird in eine Sensoraufnahme dichtend eingesetzt,
• - eine Druckdifferenz wird zwischen der Messseite und der Anschlussseite des Sensors in der Sensoraufnahme hergestellt und
• - ein Gasmassenstrom wird zwischen der Messseite und der Anschlussseite des Sensors in der Sensoraufnahme erfasst.

According to a second variant of the testing procedure, the procedure comprises the following steps:

• - the sensor is inserted into a sensor holder in a sealing manner,
• - a pressure difference is created between the measuring side and the connection side of the sensor in the sensor holder and
• - a gas mass flow is measured between the measuring side and the connection side of the sensor in the sensor holder.

A test device suitable for the test method has a sensor holder into which the sensor can be inserted in such a sealing manner that its measuring side is hermetically separated from the connection side in the sensor holder. The test device is designed to create a pressure difference between the measuring side and the connection side of the sensor in the sensor holder and to detect a pressure drop when a sensor is inserted into the sensor holder.

A further aspect relates to a vehicle component with a sensor of the type according to the invention.

Such a vehicle component, in particular a drive component, has a sensor receptacle into which a sensor according to the invention is inserted in such a sealing manner that the measuring side is hermetically separated from the connection side in the sensor receptacle. The sensor receptacle preferably has a hollow cylindrical section, on the inner wall of which a seal rests, which hermetically separates the measuring side from the connection side in the sensor receptacle. The seal is preferably formed by an O-ring.

The vehicle component is preferably a manual transmission and the sensor is preferably arranged and designed to detect a rotational speed or a shift position of a transmission component.

According to an alternative variant, the vehicle component is a hydraulic or pneumatic system and the sensor is preferably arranged and designed to detect a position of a movable system component of the hydraulic or pneumatic system.

Embodiments of the invention are now described below with reference to the drawing in comparison to the prior art, some of which is also shown. This is not necessarily intended to show the embodiments to scale; rather, where useful for explanation, the drawing is in a schematic and/or slightly distorted form. With regard to additions to the teachings immediately apparent from the drawing, reference is made to the relevant prior art. It should be noted that a wide variety of modifications and changes can be made to the shape and detail of an embodiment without deviating from the general idea of the invention. The features of the invention disclosed in the description, the drawing and the claims can be essential for the development of the invention both individually and in any combination. In addition, all combinations of at least two of the features disclosed in the description, the drawing and/or the claims fall within the scope of the invention. The general idea of the invention is not limited to the exact shape or detail of the preferred embodiment shown and described below or limited to an object that would be limited compared to the object claimed in the claims. For specified design ranges, values within the specified limits should also be disclosed as limit values and can be used and claimed as required.

• 1 eine perspektivische Außenansicht eines Sensors;
• 2 eine schematische Darstellung eines erfindungsgemäßen Sensors, eingesetzt in eine Sensoraufnahme;
• 3 eine schematische Darstellung eines alternativen Sensors eingesetzt in eine Sensoraufnahme;
• 4 eine schematische Darstellung einer weiteren Alternative eines erfindungsgemäßen Sensors, eingesetzt in eine Sensoraufnahme;
• 5 eine schematische Darstellung des Sensors aus 4, eingesetzt in eine alternative Sensoraufnahme;
• 6 eine schematische Darstellung einer Messzelle für einen Sensor der erfindungsgemäßen Art
• 7 eine schematische, perspektivische Darstellung eines Sensors in einer teilweise längsgeschnittenen Ansicht;
• 8 eine schematische, perspektivische Darstellung einer Prüfvorrichtung zum Prüfen eines Sensors der hier beschriebenen Art;
• 9 mögliche Verläufe eines mit der Prüfvorrichtung gemäß 8 erfassten Druckabfalls; und
• 10 eine Fahrzeugkomponente mit einem erfindungsgemäßen Sensor.

Further advantages, features and details of the invention will become apparent from the following description of the preferred embodiments and from the drawing, which shows in:

• 1 a perspective external view of a sensor;
• 2 a schematic representation of a sensor according to the invention, inserted into a sensor holder;
• 3 a schematic representation of an alternative sensor inserted into a sensor holder;
• 4 a schematic representation of another alternative of a sensor according to the invention, inserted into a sensor holder;
• 5 a schematic representation of the sensor 4 , inserted into an alternative sensor holder;
• 6 a schematic representation of a measuring cell for a sensor of the type according to the invention
• 7 a schematic, perspective representation of a sensor in a partially longitudinal section;
• 8 a schematic, perspective representation of a test device for testing a sensor of the type described here;
• 9 possible courses of a test device according to 8 recorded pressure drop; and
• 10 a vehicle component with a sensor according to the invention.

1 is a schematic perspective external view of a sensor 10. A sensor 10 according to the invention has a measuring cell 12 (see 2 to 7 ) which is surrounded by a housing 14 (see 1 to 7 ). The housing 14 extends from a connection side 16 to a measuring side 18. Within the housing 14, connection lines 20 extend from the measuring cell 12 to the connection side 16 of the housing 14. On the connection side 16 of the housing 14, for example, electrical contacts 22 can be provided which are connected via the connection lines 20 to corresponding connections of the measuring cell 12.

The purpose of the housing 14 is to protect the measuring cell 12 on the measuring side 18 of the housing 14 from penetrating media, such as oil or other liquids.

In use, the sensor 10 is typically inserted in a sealing manner into a sensor receptacle 24. In order to ensure sufficient tightness between the sensor housing 14 and the inner wall 26 of the sensor receptacle 24, a seal 28 is provided, which in the example shown is formed by an O-ring 30 that is inserted into a circumferential annular groove 32 on the housing 14.

As can be seen particularly from the schematic representations in the 2 to 5 As can be seen, the O-ring 30 rests on the outside on the inner wall 26 of the sensor holder 24 and on its inside on the bottom 34 of the groove 32 on the housing 14 of the sensor 10.

For reasons of tightness, but also in order to be able to insert the sensor 10 in any rotational position into the sensor holder 24, it is advantageous if the groove 32 and the O-ring 30 are formed in a ring shape around the housing 14 and the sensor holder 26 has the shape of a hollow cylinder.

In order to limit the insertion depth of the sensor 10 into the sensor holder 26, the sensor holder 24 can be designed as a stepped bore, as shown in 5 is shown. A first, proximal section 24.1 then has a larger diameter than a second, distal section 24.2, so that a shoulder 36 is formed in the sensor receptacle 24, against which a circumferential collar 38 rests on the housing 14 of the sensor 10 when the sensor 10 is fully inserted into the sensor receptacle 24. The circumferential groove 32 for receiving the O-ring 30 runs along the circumferential outside of the collar 38.

The seal 28 formed by the O-ring 30 on the outside of the housing 14 of the sensor 10 thus ensures that the measuring side 18 of the sensor 10 is hermetically separated from the connection side 16 of the sensor 10 when the sensor 10 is inserted into the corresponding, matching sensor holder 24. Accordingly, it is sufficient if the sensor housing 14 is completely sealed on the measuring side. Leaks on the connection side, which arise, for example, in the area of feedthroughs for the connection lines 20 or the contacts 22, may not be critical. On the contrary, corresponding leakage paths remaining around the connection lines 20 during injection molding have provided advantages in the past when testing the sensor. However, leakage paths open towards the connection side can be critical, especially if there is moisture ingress there in the application. Therefore, the appropriate tightness is achieved via a connector plug, i.e. the sufficient tightness of the sensor is only ensured if a connector plug is plugged into the connection side of the sensor.

A leak test therefore only works without a connection plug and the condition without a connection plug would be critical in a humid environment, as this could lead to short circuits or contamination through the leakage path to the measuring cell.

It is problematic if the sensor housing 14 has a crack 40 on the measuring side 18, because the measuring side 18 is typically exposed to adverse environmental conditions, for example within a gearbox. If the housing 14 has defects, cracks or other leaks on the measuring side 18, for example, gear oil can leak through the housing 14 to the measuring cell 18 and destroy it. Therefore, the sensor 10 is tested for leaks before installation. It is known to do this by inserting the sensor 10 into a sensor holder 24 and establishing a pressure difference between a first pressure p ₁ on the measuring side 18 and a second pressure p ₂ on the connection side 16, and to record any pressure loss that may occur. Such a pressure loss occurs when gas can flow through leaks in the housing 14 from the measuring side 18 to the connection side 16, or vice versa, depending on which of the two pressures p ₁ or p ₂ is greater. Cracks or leaks in the area of the measuring cell 18 are particularly critical here. For this test method, it is important that the seal 28 seals the sensor housing 14 well against the inner wall 26 of the sensor holder 24. However, this is usually the case and is also easy to ensure.

In order to be able to reliably detect cracks such as the crack 40 shown as an example on the measuring side 18 of the sensor housing 14, particularly in the area of the measuring cell 12, using the test method outlined, a test channel 42 is provided in the sensor housing 14, which extends from the connection side 16 to the measuring cell 12. The test channel 42 is open throughout and has a defined dimension. Preferably, the connection lines 20 do not run in the test channel 42, but rather next to the test channel 42. However, it is also possible to use the test channel to guide the connection lines. However, this is not preferred because the definition of the cross-section of the test channel can then be impaired. In the area of the measuring cell 12, the test channel 42 preferably branches off or opens into a cavity 44, which can surround the measuring cell 12. In this way, as many leaks in the housing as possible in the area of the measuring cell 12 can be detected. The test channel 42 preferably runs in a straight line between the measuring cell 12 and an opening 46 on the connection side 16 of the sensor housing 14. This allows for simple production during injection molding of the sensor housing 14.

7 shows a sensor 10 in a schematic, perspective representation in a partially longitudinally sectioned view to illustrate the possible arrangement of a cavity 44 around the measuring cell 12.

If the sensor housing 14 of a sensor 10 to be tested has a leak such as the crack 40, this can be determined using the test method outlined by the pressure difference Δp between the first pressure p ₁ and the second pressure p ₂ decreasing over time, as shown in 9 is shown in a sketch. A corresponding pressure drop Δp within a time period T ₁ can be considered a test criterion. If Δp ₁ is greater than a permitted maximum value Δp _max , the housing 14 of the sensor 10 is classified as leaking and the sensor 10 fails the test; see the dotted line for Δp in 9 . However, if the pressure difference Δp ₂ remains smaller than the maximum permitted pressure difference Δp _max within the time period T ₁ , the sensor 10 has passed the leak test; see the solid line for Δp in 9 . 8 shows a sketch of a corresponding test device 52.

The sensor housing 14 is preferably a plastic housing that is manufactured using an injection molding process. Suitable plastics for the sensor housing 14 are plastics that ensure sufficient dimensional stability and temperature resistance, e.g. glass fiber reinforced PA6.6.

The seal 28 is preferably formed by an O-ring 30, but can also be formed by an elastomer that is molded directly onto the housing 14. This can be done by means of a so-called co-injection molding process (co-molding or co-injection molding).

The measuring cell 12 is preferably a contactless measuring cell such as a Hall probe or a capacitance sensor. The functionality of such contactless measuring cells is not impaired by the sensor housing 14.

To protect the contacts 22, a casing 48 can be provided on the connection side 15 of the housing 14, which encloses a free space 50 that is open on one side, in which the contacts are arranged and which, in conjunction with a connection plug, ensures sufficient sealing in that the connection plug and the casing 48 engage in a sealing manner.

A sensor 10 according to the invention can, for example, be part of a vehicle component 60 as shown in 10 is shown by way of example in the form of a gear. The gear 60 has, for example (among other things), two intermeshing gears 62 and 64 which are accommodated in a gear housing 66 and each rotate about a shaft 68 or 70.

An oil sump 72 serves to lubricate the gears 62 and 64 of the transmission 60. In order to detect the speed of the lower gear 64 in the example shown, the transmission housing 66 has a sensor holder 74 into which a sensor 10 according to the invention is inserted. The sensor holder 74 can be designed similarly to that described above in the 4 and 5 During operation, the gears 62 and 64 of the Gearbox. In order to detect the speed of the lower gear 64, the sensor 10 is designed, for example, as a GMR sensor (a sensor based on the giant magnetoresistance effect), which provides an output signal that changes depending on the distance to the passing teeth of the lower gear 64.

The teeth of the rotating gear 64 thus model the electrical output signal of the sensor 10, so that it can be used as a speed sensor.

As in 10 As shown, the sensor 10 is typically regularly exposed to oil splashes 80 during operation of the transmission 60, so that the sensor 10 must be sealed. This is ensured by the corresponding sensor housing 14.

As in 10 is also shown, the sensor 10 is connected to a corresponding evaluation electronics (not shown) via a connection cable 76. The cable 76 has a connector plug 78 on its sensor-side end, which seals against the connection side of the sensor 10, so that the sensor 10 is also protected on its connection side, for example against moisture.

reference sign (part of the description)

10

sensor

12

measuring cell

14

sensor housing, sensor housing

16

connection side

18

measuring side

20

connection cable

22

contacts

24

sensor recording

24.1

first, proximal section of the sensor receptacle

24.2

second, distal section of the sensor receptacle

26

inner wall of the sensor holder

28

seal

30

O-ring

32

groove, circumferential annular groove

34

bottom of the groove

36

heel in the sensor mount

38

collar on the sensor housing

40

possible crack

42

test channel

44

cavity around the measuring cell

46

mouth of the test channel

48

enclosure

50

open space

52

test device

60

vehicle component; transmission

62, 64

gear

66

gearbox housing

68, 70

Wave

72

oil sump

74

sensor mount in the gearbox housing

76

connection cable

78

connector

80

oil splashes

p1

first print

p2

second print

Δp

pressure difference

Δpmax

maximum pressure difference

T1

duration

Claims (18)

Sensor (10) with housing (14) and measuring cell (12), wherein the housing (14) encloses the measuring cell (12) and extends from a connection side (16) to a measuring side (18) facing away from the connection side (16), characterized in that the housing (14) has a dedicated test channel (42) open towards the connection side (16) and extending from the measuring cell (12) to an opening (46) on the connection side (16). Sensor (10) according to claim 1 , characterized in that the housing (14) carries on its outer side a circumferential seal (28) which is arranged in the longitudinal direction of the housing (14) between the measuring side (18) and the connection side (16) and is designed to lie sealingly against an inner wall (26) of a sensor receptacle (24). Sensor (10) according to claim 2 , characterized in that the measuring cell (12) is arranged on a side of the seal (28) in the housing (14) facing away from the connection side (16). Sensor (10) according to claim 2 or 3 , characterized in that the seal (28) encloses the housing (14) in a circle. Sensor (10) according to at least one of the Claims 1 until 4 , characterized in that the measuring cell (12) is connected to at least one connecting line (20) which extends outside the test channel (42) from the measuring cell (12) to the connection side (16) of the housing (14) and possibly beyond. Sensor (10) according to claim 5 , characterized in that the housing (14) has at least one connection contact (22) on the connection side (16), which is connected to the measuring cell (12) via the at least one connection line (20). Sensor (10) according to claim 5 , characterized in that the at least one connecting line (20) is an electrical line and the measuring cell (12) is designed to output electrical measuring signals. Sensor (10) according to at least one of the Claims 1 until 7 , characterized in that the housing (14) is an injection-molded plastic housing. Sensor (10) according to at least one of the Claims 1 until 8 , characterized in that the housing (14) has on its outer side a circumferential groove (32) for receiving a seal (28) which is arranged in the longitudinal direction of the housing (14) between the measuring side (18) and the connection side (16). Sensor (10) according to at least one of the Claims 1 until 9 , characterized in that the measuring cell (12) is a Hall probe or a capacitive sensor. Vehicle component, in particular drive component, with a sensor receptacle (24) into which a sensor (10) according to one of the Claims 1 until 9 is inserted in such a sealing manner that the measuring side (18) is hermetically separated from the connection side (16) in the sensor holder (24). Vehicle component according to claim 11 , characterized in that the sensor holder (24) has a hollow cylindrical section (24.1), on the inner wall (26) of which the seal (28) rests, which hermetically separates the measuring side (18) from the connection side in the sensor holder (24). Vehicle component according to claim 12 , characterized in that the seal (28) is formed by an O-ring (30). Vehicle component according to at least one of the Claims 11 until 13 , characterized in that the vehicle component is a manual transmission and the sensor (10) is arranged and designed to detect a switching position of a transmission component. Vehicle component according to at least one of the Claims 11 until 14 , characterized in that the vehicle component is a hydraulic or pneumatic system and the sensor (10) is arranged and designed to detect a position of a movable system component of the hydraulic or pneumatic system. Test device for testing a sensor (10) according to one of the Claims 1 until 10 , with a sensor receptacle (24) into which the sensor (10) can be inserted in a sealing manner such that its measuring side (18) is hermetically separated from the connection side (16) in the sensor receptacle (24), wherein the testing device is designed to produce a pressure difference between the measuring side (18) and the connection side (16) of the sensor (10) in the sensor receptacle (24) and to detect a pressure drop when a sensor (10) is inserted into the sensor receptacle (24). Test method for testing a sensor (10) according to one of the Claims 1 until 10 on the tightness of the housing (14), whereby - the sensor (10) is inserted in a sensor receptacle (24) in a sealing manner, - a pressure difference is established between the measuring side (18) and the connection side (16) of the sensor (10) in the sensor receptacle (24), and - a pressure drop is detected as a change in the pressure difference (Δp ₁ ) between the measuring side (18) and the connection side (16) of the sensor (10) in the sensor receptacle. Test method for testing a sensor (10) according to one of the Claims 1 until 10 on the tightness of the housing (14), whereby - the sensor (10) is inserted in a sensor receptacle (24) in a sealing manner, - a pressure difference (Δp ₁ ) is established between the measuring side (18) and the connection side (16) of the sensor (10) in the sensor receptacle (24), and - a gas mass flow is detected between the measuring side (18) and the connection side (16) of the sensor (10) in the sensor receptacle (24).

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