DE102019207435A1 - Underrun protection - Google Patents

Abstract

The invention relates to an underrun protection for a vehicle, the underrun protection (8) being arranged above the terrain (2) on the underbody (4) of the vehicle and made up of at least three layers, namely an outer layer (11) adjacent to the terrain being traveled on, one of the Inside the vehicle adjacent inner layer (13) and an intermediate layer (12, 12.1, 12.2, 12.3, 12.4) generating a defined distance (a) between the outer layer (11) and the inner layer (13). According to the invention, the layers are such that when a defined force is exceeded from the terrain (2) on the outer layer (11), the intermediate layer (12, 12.1, 12.2, 12.3, 12.4) and / or the outer layer (11) and the Intermediate layer (12, 12.1, 12.2, 12.3, 12.4) are deformed by reducing the distance (a) between outer layer (11) and inner layer (13), the outer layer (11) and the inner layer (13) and / or on the outer layer (11) and / or the inner layer (13) directly or indirectly arranged elements are parts of an electrical circuit or act on parts of an electrical circuit. An approach of the outer layer (11) and the inner layer (12) and / or the elements arranged directly or indirectly thereon causes a detectable change in the electrical properties of the electrical circuit.

Description

The invention relates to an underrun protection for a vehicle, in particular a motor vehicle according to the preamble of claim 1.

The core of the invention relates to deformation monitoring, in which the vehicle driver is informed of the possible severity of a ground collision. The invention enables the driver to distinguish or perceive weak, uncritical underbody impacts from stronger underbody impacts, so that the need for tests can be derived. This also results in options to minimize the requirements for collision protection.

The structural integrity of components with a protective effect is of crucial importance for vehicle construction. Lightweight structures in particular can completely lose their structural integrity due to impact damage, with external damage often only being visible to a small extent or being perceived as insignificant by a layperson. This is particularly problematic when the components are installed in places that are difficult to see from the outside, for example on the underbody of a vehicle.

In vehicles, in particular motor vehicles, the underbody is exposed to a wide range of stresses which the vehicle driver often does not notice or only does not notice. Rock falls or small bumps when driving on uneven terrain are among others such events. Even if such an event is perceived by the vehicle driver, it is difficult to assess the extent of the damage.

Currently, vehicles are increasingly being used, the energy storage of which places particular demands on protection against damage. In electric vehicles, for example, high-voltage batteries are installed as traction batteries, which represent a high risk of fire if damaged. The same applies to vehicles operated with hydrogen or CNG (Compressed Natural Gas). Here, the traction batteries or gas tanks are mostly arranged in the area between the vehicle underbody and the passenger compartment floor below the relatively stiff passenger compartment in order to minimize damage to the energy storage device in the event of a collision with another vehicle or object, and thus a risk to the occupants from the energy storage device. In addition, such an arrangement of the energy store shifts the center of gravity of the vehicle as far down as possible in the direction of the terrain being traveled on, thereby optimizing driving stability.

An arrangement of an energy store in this area, however, brings with it the problem that an energy store arranged in this way can be damaged in the event of a landing, that is to say when driving over an object that is larger than the ground clearance of the vehicle. For this reason, so-called underrun protection is installed in such vehicles, which is intended to prevent damage to the energy storage device. A corresponding underrun protection is in the DE 10 2016 207 231 A1 refer to. The description describes the arrangement of an electrical high-voltage energy store on a motor vehicle, the high-voltage energy store being arranged in the area of an underbody of the motor vehicle and being at least partially covered in the vertical direction of the vehicle by a floor element. In this case, in the vertical direction of the vehicle between the high-voltage energy store and the floor element, at least one load distribution element is arranged in a gap, via which the floor element can be supported on the high-voltage energy store. In this way, a force acting in the vertical direction of the vehicle, that is to say from bottom to top, is distributed over a large area on the energy storage device, which counteracts damage. Provision is also made for the floor element to be embodied in multiple layers in such a way that forces are reduced by deformation of an intermediate layer. In order to be able to detect a force acting on the energy store, it is also proposed to provide a sensor system between the load distribution element and the energy store in order to detect or measure the force acting on the energy store.

The disadvantage of this arrangement is that it is not possible to detect the complete or partial loss of the structural integrity of the floor element. This is particularly disadvantageous when the floor element itself represents the only underrun protection, that is to say an additional load distribution element is not provided. If the structural integrity of the floor element is lost as a result of a first application of force, a second application of force could be entered into the energy store without braking.

With regard to the detection of a force application, it is from the DE 10 2004 005 566 A1 known to provide an at least two-layer structure in the longitudinal direction of the vehicle between a bumper cladding and a bumper crossmember, which consists of a first layer facing the bumper lining and a second layer facing the bumper crossmember. The first layer is softer in impact than the second layer, so that in the event of an impact of an object on the bumper cladding by means of the sensor device, in the event of an impact-related force on the soft first layer The penetration speed can be determined and a penetration force value can be determined in the event of an impact-related force acting on the impact-hard second layer. In addition, at least one evaluation device is provided, by means of which at least one object mass and one object speed can be calculated as a function of the determined penetration speed and the determined penetration force variable.

On the basis of the prior art discussed above, the object of the invention is to provide an arrangement which is designed on the one hand as underrun protection and largely intercepts forces acting on the arrangement from below in the vertical direction of the vehicle and on the other hand acts as a sensor arrangement, so that the complete or partial loss of the structural integrity of the underrun protection can be determined.

The problem is solved by the features of the main claim. Advantageous refinements and developments are disclosed in the dependent claims.

The starting point is an underrun protection for a vehicle, the underrun protection being arranged above the terrain being traveled on on the underbody of the vehicle and comprising at least three layers, an outer layer adjacent to the terrain being traveled on, namely an inner layer adjacent to the vehicle floor and a defined distance between outer layer and inner layer generating intermediate layer.

To solve the problem, it is proposed that the layers are designed in such a way that when a defined force is exceeded from the terrain being traveled on the outer layer, first the intermediate layer and / or the outer layer and the intermediate layer are deformed while reducing the distance between the outer layer and the inner layer, whereby the outer layer and the inner layer and / or elements arranged directly or indirectly on the outer layer and / or the inner layer are parts of an electrical circuit or act on parts of an electrical circuit and that an approach of the outer layer and the inner layer and / or the direct or indirect thereto arranged elements causes a detectable change in the electrical properties of the electrical circuit.

The embodiment according to the invention advantageously ensures that, on the one hand, there is a deformation-resistant structure which, when force is applied from below in the vertical direction of the vehicle, dissipates these forces or reduces them by deforming the underrun protection. On the other hand, the underrun protection is at the same time a sensor with the aid of which it can advantageously be detected whether the structural integrity of the underrun protection is given. If the structural integrity of the underrun protection is completely or partially disturbed by a single or multiple application of force from below in the vertical direction of the vehicle, for example by placing the underrun protection on uneven terrain, a renewed application of force could, under certain circumstances, be entered into the energy storage without braking, this is determined by the sensor properties of the underrun protection safely avoided in an advantageous manner.

The underrun protection is advantageously at least part of the vehicle underbody or is designed integrally with it. It is particularly advantageous if the underrun protection forms a plane with the vehicle underbody.

An advantageous embodiment of the underrun protection provides that the intermediate layer has a corrugated structure, a honeycomb structure, a web structure, a knob structure or any mixture thereof, the structures being arranged such that they support the outer layer against the inner layer. This saves material on the one hand, and a high level of rigidity is achieved on the other. For this purpose, the intermediate layer is advantageously connected to the outer layer and / or the inner layer in a materially bonded, form-fitting, non-positive or frictional manner.

In an advantageous further development of the arrangement, it can be provided that the elements have an arrangement, at least in partial areas, such that they form a matrix. In this way it can be determined not only that a force has been applied to the underrun protection, but also in which area of the underrun protection. In this way, it can be determined even more precisely whether the underrun protection is still fulfilling its function despite the registered force.

Different physical principles can be used to detect the effect of a force on the underrun protection. The approach of the outer layer and the inner layer and / or the approach of the elements arranged directly or indirectly on the outer layer and / or the inner layer can advantageously be detected by capacitive, inductive, optical, conductive, or resistance-changing effects, the effects mentioned being direct or indirect indirectly influence the properties of the electrical circuit. Of course, it can also be any mixture of the aforementioned effects. Which of the operating principles is used depends on the respective framework conditions, for example on which materials - conductive or non-conductive - which of the layers of the underrun protection is made or on how the intermediate layer is designed.

A further advantageous development of the arrangement provides that the underrun protection comprises a first evaluation device which detects and evaluates a change in the electrical properties of the electrical circuit and / or the degree of change in the electrical properties of the electrical circuit and a notification device for the driver of the vehicle and / or a memory device for reading out by the maintenance personnel during a workshop visit. This advantageously means that the action of a force on the underrun protection can be treated differently depending on the respective circumstances. If the force is only slight or if it is in an area that only slightly influences the structural integrity of the underrun protection, it is sufficient for the evaluation device to feed the event to a memory device for later reading by the maintenance personnel when they are in the workshop. If, on the other hand, it is a question of a force that seriously impaired the structural integrity of the underrun protection, an alert to the driver is mandatory. Further measures, such as separating the energy store from lines, etc., can possibly also be derived from such a serious force.

In particular, if the vehicle is an electric vehicle, it is advantageous if the underrun protection forms the cover of a cavity arranged in the area between the passenger compartment floor and the underbody, in which an energy store, for example a traction battery, is arranged. With this configuration, the energy store can be exchanged without great effort. In general, even if the energy store is a storage container that holds a liquid or a gas, the design of the underrun protection as a cover is advantageous because an underrun protection configured in this way can be replaced after a force without great assembly effort. The replacement not only restores the structural integrity of the vehicle's underbody, but also renews the sensors at the same time without any additional effort.

As an additional advantageous measure, at least one pressure transducer can be arranged on the underrun protection between the inner layer and the energy store, by means of which a pressure increase on the energy store can be sensed when the underrun protection is deformed in the direction of the energy store. The pressure transducer is advantageously designed as an electrical pressure measuring film known per se, which changes its electrical properties when a force is applied. It is also advantageous if the underrun protection comprises a second evaluation device which evaluates a change detected by the electrical pressure sensor and / or the degree of change detected by the pressure sensor and a notification device for the driver of the vehicle and / or a memory device for storing and later reading out by the maintenance staff during a workshop visit. The latter can mean that lines are separated from the energy storage device immediately after the force has been applied, for example by being blown off.

• 1 Prinzipdarstellung eines Personenkraftfahrzeugs mit Unterfahrschutz beim Befahren eines unebenen Geländes
• 2a Prinzipdarstellung einer ersten Ausführungsform des Unterfahrschutzes
• 2b Prinzipdarstellung einer zweiten Ausführungsform des Unterfahrschutzes
• 2c Prinzipdarstellung einer dritten Ausführungsform des Unterfahrschutzes
• 2d Prinzipdarstellung einer vierten Ausführungsform des Unterfahrschutzes
• 3a Prinzipdarstellung einer fünften Ausführungsform des Unterfahrschutzes
• 3b Draufsicht auf die Zwischenlage aus 3a
• 3c Prinzipdarstellung der fünften Ausführungsform des Unterfahrschutzes gemäß 3a nach einer Bodenberührung

Further refinements and advantages of the invention are explained in more detail below with reference to the drawing. Show it:

• 1 Schematic representation of a passenger vehicle with underrun protection when driving on uneven terrain
• 2a Schematic representation of a first embodiment of the underrun protection
• 2 B Schematic representation of a second embodiment of the underrun protection
• 2c Schematic representation of a third embodiment of the underrun protection
• 2d Schematic representation of a fourth embodiment of the underrun protection
• 3a Schematic representation of a fifth embodiment of the underrun protection
• 3b Top view of the liner 3a
• 3c Schematic representation of the fifth embodiment of the underrun protection according to 3a after touching the ground

1 shows a schematic representation of a passenger vehicle 1 when driving on uneven terrain 2 in by the direction arrow 3 designated direction. To the terrain 2 the passenger car indicates 1 a sub-floor 4th that locks the vehicle down. Between the sub-floor 4th and that in the vertical direction of the vehicle 25th seen above the passenger compartment floor indicated by a dashed line 5 there is a cavity 6th , in which an energy store also indicated by a dashed line 7th is arranged. To the energy storage 7th when the sub-floor comes into contact with the floor 4th to protect is in the sub-floor 4th in the field of energy storage 7th an underrun protection 8th integrated. The underrun protection 8th can be an integral part of the sub-floor 4th his or one in the sub-floor 4th Form embedded or placed on this cover over which the energy storage 7th is accessible. In any case, the underrun protection 8th in the vertical direction of the vehicle 25th stiff on parts of the body (not shown) of the passenger vehicle 1 supported.

As in 1 by the power arrow 9 indicated, it is in the selected example (when driving on uneven terrain 2 ) to touch the underrun protection 8th with a bump in the terrain 2 came. Such ground contact is generated due to the weight of the passenger car 1 , one by the power arrow 9 indicated force in the vertical direction of the vehicle 25th that are on the underrun protection 8th acts. Such a force can damage the integrity of the structure of the underrun protection 8th affect. If the passenger car 1 continue in the direction of the direction arrow 3 moved, it would be at the elevation indicated by an arrow 10 come to a renewed ground contact, so that the resulting renewed force effect in the vertical direction of the vehicle 25th , in the case of an underrun protection that has already been structurally damaged by the first contact with the ground, the energy storage device is essentially unbraked 7th would hit. To prevent this, the underrun protection 8th designed as an overall system so that damage to the structural integrity of the underrun protection 8th is detected by this itself. After evaluating a detected force acting on the underrun protection, warning and / or control measures can then be initiated if necessary.

To explain how an underrun protection can be constructed as an example, the in 1 Partial area outlined with a semicolon line in 2a shown cut. The line of intersection runs in the longitudinal direction of the vehicle through the area described above and shows the underrun protection 8th , the energy storage 7th and the passenger compartment floor 5 . The latter is only indicated in dashed lines.

The underrun protection 8th consists according to the figure in 2a in the vertical direction of the vehicle 25th seen from one of the traveled terrain 2 facing outer layer 11 , a liner 12 and one the energy storage 7th facing inner layer 13 . To illustrate how the underrun protection works 8th is shown in the middle of the illustration that an increase in the area traveled 2 with the underrun protection 8th has collided. Because of this on the underrun protection 8th acting, through the power arrow 14th The symbolized force caused a deformation of the underrun protection. The processes involved in deformation will be discussed in greater detail below.

As can be seen from the sectional view, it is in the vertical direction of the vehicle 25th to the outer layer 11 subsequent intermediate layer 12 as an accordion-shaped corrugated layer 26th educated. The kinks of the accordion-shaped corrugated layer 26th come in each case alternately on the side of the outer layer facing them 11 , or the side of the inner layer facing them to the system and thus form system lines running into the plane of the drawing 15th , the outer layer 11 and inner layer 13 support each other. On these investment lines 15th is the liner 12 preferably by a material connection with the outer layer 11 one hand and the inner layer 13 on the other hand connected. Opposite the investment lines 15th on the outer layer 11 are on the inner layer 13 , on her liner 12 facing side, contact elements 16 parallel to the investment lines 15th fixedly arranged running into the plane of the drawing. The contact elements 16 consist of an insulating layer 17th and a contact layer 18th . The insulating layer 17th is on the inner layer 13 , on her liner 12 facing side firmly arranged, the contact layer 18th turn is on the insulating layer 17th , adjacent to the intermediate layer 12 firmly arranged.

A loss of the structural integrity of the underrun protection 8th To be able to determine, it is further provided that on the one hand the contact layers 18th of all contact elements 16 with a first evaluation device 20th are electrically connected, on the other hand is the outer layer 11 , which consists of an electrically conductive material, also with the first evaluation device 20th connected so that the contact layers 18th the contact elements 16 a first level of contact 21st and the outer layer 11 a second level of contact 22nd form.

In addition to the underrun protection described above 8th is in the selected example at the vehicle vertical direction 25th seen from the lower side of the energy store 7th a pressure measuring film 23 arranged with a second evaluation device 24 connected is. In this way, a force is introduced into the energy store 7th registrable.

To explain how the underrun protection works 8th is shown in 2a assumed that a contact of the traveled area 2 with the underrun protection 8th has taken place. This force action is shown with a force arrow 14th marked. The outer layer became 11 in the vertical direction of the vehicle 25th deformed, causing the liner 12 has collapsed at this point. As a result of the collapse of the intermediate layer 12, the outer layer has become 11 , in reducing the distance a, so far towards the inner layer 13 bulging that the outer layer 11 in electrical contact with one of the contact elements 16 has arrived. The contact point is shown with a jagged arrow 19th symbolically designated. This contact between the first contact level 21st and the second contact level 22nd is from the first evaluation device 20th registered. Various tax measures can be derived from the registered contact. This is done by having a higher-level Control device (not shown), for example, initiates a notification device for the driver of the vehicle and / or a storage process for storing the event in a fault memory. The storage of the event in a fault memory serves to inform the workshop personnel about the event during a later visit to the workshop by reading out the fault memory and, if necessary, to exchange the underrun protection 8th to cause.

As stated above, is on the underside of the energy store 7th a pressure measuring film arranged. This is an additional measure to directly detect a force input into the energy storage device through contact with the ground. Such an application of force occurs when there is ground contact with the terrain being traveled on 2 the inner layer 13 of the underrun protection 8th deformed so far in the vertical direction of the vehicle that it is in contact with the pressure measuring film 23 got. Such a contact is made by the second evaluation device 24 registered and, if necessary, the amount of force input measured so that control measures can be derived directly from this event.

The above in connection with 2a described training of the intermediate layer 12 can of course also have a different shape, corresponding examples are in 2 B , 2c , and 2d shown. Since there is only the intermediate layer from the example according to 2a differs, only this difference is described below. As far as the individual parts correspond to the parts in 2a correspond, the same reference numerals are used, differences with regard to the reference numerals are identified with an index after a point. In the 2 B , 2c and 2d The upper images in each case show a section through the underrun protection similar to the left-hand section of the underrun protection 8th according to 2a . In the 2 B , 2c and 2d The lower figures in each case show a top view of the intermediate layer looking against the vertical direction of the vehicle 25th , the inner layer 13 the position of the contact elements is omitted in these figures 16 is shown in a dashed line.
2 B shows instead of the accordion-shaped corrugated layer 26th ( 2a) as an intermediate layer 12.1 a sinusoidal corrugation 26.1 . At the wave crests and troughs of the sinusoidal corrugation 26.1 supports these, respectively investment lines 15.1 forming the outer layer 11 against the inner layer 13 from. The attachment lines are to increase strength 15.1 the sinusoidal corrugation 26.1 preferably cohesively with the outer layer 11 one hand and the inner layer 13 on the other hand connected. The functionality does not differ from that in connection with 2a , reference is therefore made to the description of the function above.

Another possible embodiment of the intermediate layer is shown in FIG 2c shown. Here is in place of the accordion-shaped corrugated layer 26th ( 2a) as an intermediate layer 12.2 a grate 27 with square grid openings 28 used. For reasons of clarity, not all grid openings are provided with reference symbols in the illustration. The walls of the grating 27 extend in the vertical direction of the vehicle 25th between the outer layer 11 and the inner layer 13 and support them along the installation lines 15.2 against each other. Here, too, preference is given to the contact lines resulting from the support 15.2 a material connection between the outer layer 11 and liner 12.2 one hand and inner layer 13 and liner 12.2 on the other hand makes sense. Because of the walls of the grating that extend parallel to the force input 27 but this is not absolutely necessary. In this embodiment it is provided that the contact elements 16 . 1 has the same basic square shape as the grid openings 28 exhibit. The connection of the contact elements 16.1 with each other or with the first evaluation device 20th ( 2a) can take place in extreme cases so that each individual contact element 16.1 separately with the first evaluation device 20th ( 2a) is connected, but there can also be rows of contact elements 16.1 or all contact elements 16.1 with each other and then with the first evaluation device 20th ( 2a) be connected.

A slightly differently shaped intermediate layer 12.3 shows 2d . This example is also a grating 27.1 crafted liner 12.3 , in which the grid walls are in the vertical direction of the vehicle 25th extend the grille openings 28.1 however, are designed in the shape of a regular hexagon. For a better overview, not all grid openings are provided with reference symbols here either. The one in the vertical direction of the vehicle 25th between the outer layer 11 and the inner layer 13 extending walls of the grating 27.1 also form investment lines in this example 15.3 and support the outer layer 11 and inner layer 13 against each other. As in the example described above, a material connection between the outer layer can also be used in this case 11 and liner 12.3 or between the inner layer 13 and liner 12.3 be useful, but this is due to the walls of the grating extending parallel to the force input 27.1 not mandatory. As in the examples described above, there are also contact elements here 16.1 are provided which, when viewed from above, have a square basic shape, in contrast to the example described above, however, not all grid openings are present 28.1 with a contact element 16.1 fitted. In the example chosen here, there is between two grid openings 28.1 with contact elements 16.1 a grid opening 28.1 arranged without contact element. Of course, different from the example, several grid openings can also be used 28.1 be without a contact element between two grid openings 28.1 with contact elements 16.1 lie. The connection of the contact elements 16.1 with the first evaluation device 20th ( 2a) , or with each other and with the first evaluation device 20th ( 2a) , can as above too 2c described, take place differently.

An embodiment of an underrun protection that differs from the examples described above is described below in connection with 3a , 3b and 3c described. It shows 3a , analogous to 2a , a sectional view through the underrun protection 8th (see. 1 ). The cut runs in the longitudinal direction (corresponds to the direction of travel 3 of the passenger vehicle 1 in 1 ). As shown in 3a the underrun protection exists 8th also in this exemplary embodiment in the vertical direction of the vehicle 25th seen from one of the traveled terrain 2 facing outer layer 11 , a liner 12 and one the energy storage 7th facing inner layer 13 .

How out 3a can be seen, which is the area traveled on 2 facing outer layer 11 the underrun protection 8th from a first conductive support element 44 formed to the traveled terrain 2.1 with a coating of underbody protection 55 is provided. In the vertical direction of the vehicle 25th the intermediate layer closes 12 which consists of a non-conductive, three-dimensionally shaped, studded mat 66 consists.

To better illustrate the design of the intermediate layer 12 is the mat 66 in 3b in plan view from above, i.e. from the direction of the inner layer 13 shown, the following statements therefore relate to 3a and 3b . The knobs are made up of regularly arranged straight truncated pyramids that are equally spaced from one another 46 formed that to the inner layer 13 towards a square top surface 47 have and so through the top surfaces 47 Form a ceiling plane that leads to the inner layer 13 runs parallel. Due to the mutually uniform spacing of the in the direction of the outer layer 11 open truncated pyramids 46 the result is a grid-shaped floor level 48 who in turn to the outside position 11 runs parallel. In the deck areas 47 are circular penetrations 49 arranged.

In the vertical direction of the vehicle 25th , above the intermediate layer 12 is, as mentioned above and in 3a shown, the inner layer 13 arranged. This consists of a second support element 50 that at its the liner 12 facing side a contact layer 51 having. The contact layer 51 carries molded cylindrical contact elements on it 52 and is, if the second support element 50 is conductive, with the formation of an insulating layer cohesively with the second support element 50 , for example connected by gluing.

The in 3a shown assembled state of the outer layer 11 , the liner 12 and the inner layer 13 built underrun protection 8th indicates that the contact elements 52 with the penetrations 49 correspond and take action. Next are the top surfaces 47 with the contact layer 51 preferably cohesively connected, for example by gluing. In order to create a stiff composite, the grid-shaped floor plane is 48 the liner 12 on their outer layer 11 facing bottom 54 also firmly bonded to it, for example by gluing, so that a sandwich-like structure of high rigidity is provided. The design of the underrun protection 8th against force in the vertical direction of the vehicle 25th is made so that with such a force from the traveled terrain 2 on the outer layer 11 , the liner 12 is compressed under deformation and thus force reduction, so that the distance a between the outer layer 11 and inner layer 13 decreased. It should be noted here that due to the inclusion of air in the truncated pyramids 46 an additional force reduction takes place through compression work, as is the case with a bubble wrap.

In the vertical direction of the vehicle 25th is above the underrun protection 8th , through a gap 57 spaced, the energy storage 7th arranged. Energy storage 7th and sub-floor 8th are (not visible in the illustration) independently of one another on the body of the passenger vehicle, for example on its passenger compartment floor 5 attached.

To the underrun protection 8th The contact layer is designed as a sensor 51 on the one hand and the first support element 44 on the other hand with an evaluation circuit 53 electrically connected, the contact elements 52 in connection with the first support element 44 and the evaluation circuit 53 form a circuit with a plurality of open, electrically parallel switches. If the ground now comes into contact, the intermediate layer becomes 12 pressed together. Depending on the strength of the force, the distance a between the outer layer can be 11 and inner layer 13 reduce so far that the first support element 44 in contact with the contact elements 52 what gets through the evaluation circuit 53 is detected as closing the circuit.

Shows a situation in which the ground has been touched 3c . As can be seen from the illustration when driving on the site 2 ground contact has taken place, one of which is caused by the force arrow 61 indicated force effect. As a result of the force, the intermediate layer became 12 and here in particular the truncated pyramids 46 ( 3a) compressed while reducing the distance a so that their wall 46.1 has collapsed. This has led to contact elements 52 and first support element 44 at the contact points 56 touch and close the circuit mentioned above. The evaluation circuit 53 registers this event, so that the fact of a ground contact with impairment of the integrity of the underrun protection 8th A higher-level control device (not shown), as it is present in every modern motor vehicle today, can be used to initiate further control processes. This can be a notification device for the driver of the vehicle through appropriate signaling and / or a storage process with which the event is recorded in a memory device for later reading by the maintenance personnel when visiting the workshop. Finally, the above-described and by the evaluation circuit 53 registered ground contact can be used by the higher-level control device (not shown) to initiate further control processes.

Contact with the ground could also reduce the structural integrity of the energy store 7th be impaired. In order to also capture this fact, as in 3a and 3c shown with a dashed line, between the underrun protection 8th and the energy storage 7th in the gap 57 a sensor arrangement 58 be provided with a second measuring circuit also shown in dashed lines 59 connected is. This can, for example, be a pressure measuring film which is inserted into the energy storage device due to possible bending of the underrun protection when it touches the ground 7th registered force is detected. Again, from the measuring circuit 59 further control processes can be initiated by means of a higher-level control device (not shown).

In order to be able to make an assessment regarding the extent of the damage to the underrun protection, the above is based on 3a to 3c described example the possibility in place of the contact layer 51 that extends flat over the underside of the second support element 50 extends, contact strips 60 to use as they are in 2 B are indicated schematically in dashed lines. In this case the contact strips are 60 to inquire cyclically one after the other whether a contact has been made in order to be able to make an approximate assessment of the extent of the damage. A more precise assessment of the extent of damage is possible if the mating contacts (not shown) are also strip-shaped and at ninety degrees to the contact strips 60 rotated on the first support element 44 compared to the contact elements 52 and to the first support element 44 are arranged isolated. If the resulting matrix of switching elements is queried by the evaluation device in rows and columns for closed switching elements, the size and location of the damage can be better estimated.

Finally, it should be noted that the above-described detection of a loss of the structural integrity of the underrun protection is not limited to conductive means in the form of switches; capacitive, inductive, optical or resistive means or any mixture of such means can of course also be used to a reduction in the distance a between the outer layers 11 and inner layer 13 to detect.

List of reference symbols

1

Passenger vehicle

2

terrain

3

Direction arrow

4th

Subfloor

5

Passenger compartment floor

6

cavity

7th

Energy storage

8th

Underrun protection

9

Power arrow

10

Terrain elevation

11

Outer layer

12, 12.1, 12.2, 12.3, 12.4

Liner

13

Inner layer

14th

Power arrow

15, 15.1, 15.2, 15.3

Investment lines

16, 16.1

Contact elements

17th

Insulating layer

18th

Contact layer

19th

jagged arrow

20th

first evaluation device

21st

first contact level

22nd

second contact level

23

Pressure measuring film

24

second evaluation device

25th

Vehicle vertical direction

26th

accordion-shaped corrugated layer

26.1

sinusoidal corrugation

27, 27.1

Grating

28, 28.1

Grid opening

44

first support element

46

Truncated pyramid

46.1

Wall (truncated pyramids)

47

Top surface

48

grid-shaped ground plane

49

Penetration

50

second support element

51

Contact layer

52

Contact element

53

Evaluation circuit

54

Bottom (of the liner 12.4 )

55

Underbody protection

56

Contact points

57

gap

58

Sensor arrangement

59

Measuring circuit

60

Contact strips

61

Force action arrow

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102016207231 A1 [0006]
• DE 102004005566 A1 [0008]

Claims (13)

Underrun protection for a vehicle, the underride protection (8) being arranged above the terrain (2) on the underbody (4) of the vehicle and made up of at least three layers, namely an outer layer (11) adjacent to the terrain being traveled on, an inner layer (11) adjacent to the vehicle interior ( 13) and an intermediate layer (12, 12.1, 12.2, 12.3, 12.4) generating a defined distance (a) between the outer layer (11) and the inner layer (13), characterized in that the layers are made so that when a defined Force from the terrain (2) on the outer layer (11) first the intermediate layer (12, 12.1, 12.2, 12.3, 12.4) and / or the outer layer (11) and the intermediate layer (12, 12.1, 12.2, 12.3, 12.4) are deformed while reducing the distance (a) between the outer layer (11) and the inner layer (13), the outer layer (11) and the inner layer (13) and / or on the outer layer (11) and / or the inner layer (13) directly or indirectly arranged elements parts e an electrical circuit or act on parts of an electrical circuit, and that an approach of the outer layer (11) and the inner layer (12) and / or the elements directly or indirectly arranged thereon causes a detectable change in the electrical properties of the electrical circuit. Underrun protection after Claim 1 , characterized in that the underrun protection (8) is at least part of the underbody (4) of the vehicle. Underrun protection after Claims 1 or 2 , characterized in that the intermediate layer (12, 12.1, 12.2, 12.3, 12.4) has a corrugated structure, a grating structure, a knob structure or any mixture thereof, the structures being arranged in such a way that they place the outer layer (11) against the inner layer ( 13). Underrun protection after Claims 1 or 2 , characterized in that the intermediate layer (12, 12.1, 12.2, 12.3, 12.4) is connected to the outer layer (11) and / or the inner layer (13) in a materially bonded, form-fitting, force-fitting or frictional manner. Underrun protection according to one of the preceding claims, characterized in that the elements have an arrangement at least in partial areas such that they form a matrix. Underrun protection according to one of the preceding claims, characterized in that when the outer layer (11) and the inner layer (13) approach and / or when the elements arranged directly or indirectly on the outer layer (11) and / or the inner layer (13) approach, these change the electrical properties of the electrical circuit through capacitive, inductive, optical, conductive, or resistive influence or any mixture of these influences. Underrun protection according to one of the preceding claims, characterized in that the underride protection (8) comprises a first evaluation device (20) which detects, evaluates and detects a change in the electrical properties of the electrical circuit and / or the degree of change in the electrical properties of the electrical circuit a notification device for the driver of the vehicle and / or a memory device for reading out by the maintenance personnel during a workshop visit. Underrun protection according to one of the preceding claims, characterized in that the underride protection (8) is the cover of a cavity (6) arranged in the area between the vehicle floor (5) and the underbody (4) in which an energy store (7) is arranged. Underrun protection after Claim 8 , characterized in that the energy store (7) is a traction battery of an electric vehicle. Underrun protection after Claim 8 , characterized in that the energy store (7) is a storage container that holds a liquid or a gas. Underrun protection according to one of the Claims 8 to 10 , characterized in that at least one pressure sensor is arranged between the inner layer (13) and the energy store (7) by means of which a pressure increase on the energy store (7) can be sensed when the underrun protection (8) is deformed in the direction of the energy store (7) . Underrun protection after Claim 11 , characterized in that the pressure sensor is an electrical pressure measuring film (23). Underrun protection according to one of the Claims 11 or 12 , characterized in that the underrun protection (8) comprises a second evaluation device (24) which evaluates a change detected by the pressure transducer and / or the degree of the change detected by the pressure transducer and a notification device for the driver of the vehicle and / or a storage device for reading by the maintenance staff during a workshop visit.

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