WO1995031355A1

WO1995031355A1 - Motor vehicle

Info

Publication number: WO1995031355A1
Application number: PCT/EP1994/001612
Authority: WO
Inventors: Albrecht Hartmann; Jörg R. Bauer
Original assignee: Albrecht Hartmann; Bauer Joerg R
Priority date: 1994-05-18
Filing date: 1994-05-18
Publication date: 1995-11-23
Also published as: JPH09500591A

Abstract

A motor vehicle, in particular a compact vehicle, has a car body structure that is in itself rigid, that contains a useful space and that bears flat outer skin parts (8, 10, 12). The vehicle has an impact protection unit that allows a vehicle part to move from a retracted position into a deployed position in which the vehicle base surface is increased. When the vehicle collides with an obstacle, the deployed vehicle part reduces deformation of the useful space by moving towards the vehicle. The deployable vehicle part is one of the flat outer skin parts (8, 10, 12).

Description

Motor vehicle

The invention relates to a motor vehicle according to the preamble of claim 1.

An essential safety element of modern motor vehicles are the so-called crumple zones, which are present in particular in front of and behind the deformation-resistant passenger compartment. These crumple zones are designed in such a way that they deform in a targeted manner in the event of an accident, so that the very sudden braking, for example the front bumper suffers in the event of a front impact, is converted into a softer braking of the interior, which increases the chance of survival for the vehicle occupants ¬ sen enlarged.

In view of the high traffic density and the parking problems, particularly in conurbations, the compact design of the motor vehicles is an increasingly important design goal. In such compact vehicles, in which the footprint occupied by the vehicle is only as little as possible larger than the usable space available for the usable space, there is a problem in that there is only extremely limited space available for crumple zones. As a result, the safety of the vehicle occupants in compact vehicles is adversely affected.

There are numerous suggestions for solving the conflict of objectives of high safety through crumple zones with a compact construction of the vehicle, for example by the front bumper being extendable from the vehicle while it is moving and being retracted into the vehicle when the vehicle is stationary. By appropriate design of the bumper itself and the mechanism extending this ensures that the extended bumper together with the extension mechanism forms a crumple zone which absorbs energy in the event of an accident and slows down the braking of the interior. Nevertheless, the parking space used by the vehicle is driven bumper very low.

The known constructions have the following characteristics:

- They are dangerous for pedestrians because they only hit a colliding pedestrian at bumper height in the area of the knees, which leads to great risk of injury. In addition, a detected pedestrian is knocked over in the event of an impact and then hits the vehicle in an extremely dangerous manner for him.

- The extended bumper can be run over by an impacting vehicle, so that the crumple zone achieved by the extended bumper is ineffective.

The invention has for its object to provide a generic motor vehicle with increased accident safety.

This object is achieved with the features of the main claim.

The design of the motor vehicle according to the invention ensures that the risk of injury, in particular for pedestrians, is considerably reduced, since the flat outer skin part covers a pedestrian over a large area and does not knock him down. Furthermore, the extended, flat outer skin part cannot easily be run over by the bumper of an opposing vehicle, as a result of which the crumple zone formed by the extended flat outer skin part is reliably effective. Furthermore, an additional material is available for energy reduction.

With the features of claim 2 it is achieved that, with maximum usable space, only minimal parking space is required.

Claim 3 characterizes a very advantageous embodiment of the motor vehicle, in which the flat outer skin part forms a kind of protective shield in front of the vehicle together with the front bumper.

With the features of claim 4, the occupant safety in side impact accidents is increased.

The claim 5 is directed to an embodiment in which a high level of safety is achieved even in the event of a rear-end collision, which is particularly the case in compact vehicles in which there is little space behind the front passengers, or also in combination vehicles in which the rear loading space, for example, is one Child seat takes up is important.

With the features of claim 6 it is achieved that there is sufficient material or structural elements available for the deformation energy to be reduced in the accident, which on the one hand simplifies the design and on the other hand improves occupant safety.

Claims 7 to 9 are directed to particularly simple but very effective embodiments of the deformable support parts or struts.

With the features of claim 10, the surface of the flat, extendable outer skin part is used in a particularly effective manner, an appropriately constructed air bag being additionally very economical in weight and capable of reducing energy.

With the features of claim 11, occupant safety is additionally increased, since the air cushion arranged in the vehicle interior prevents a vehicle occupant from colliding with hard interior structures. This additional air cushion is very inexpensive because it does not require its own release or inflator. There can be several air cushions, for example on the upper longitudinal spars, the door parapets, on the steering wheel, on the Control panel be provided in front of the front passenger, etc.

With the features of claim 12, the airbag is used not only for energy dissipation in the event of an accident, but also for moving the flat outer skin part.

With the features of claim 13, the force-displacement characteristic or the energy absorption capacity of the crumple zone can be adapted to the respective requirements, for example the vehicle speed or the vehicle load. In the event of a collision with a rigid obstacle in particular, it is advantageous if the gas pressure in the airbag is lower than in the case of a heavily loaded vehicle when the vehicle is not heavily loaded, so that the crumple zone comprising the airbag and the flat outer skin part is sufficiently "softly" deformable.

With the features of claim 14, the force-displacement characteristic of the crumple zone can be adapted to the respective requirements by appropriate selection of the chambers and the valves.

With the features of claim 15, a precisely defined filling of the individual chambers of the airbag with the respective gas volumes is possible. If the pressure source is a pressure accumulator, the gas used to inflate the airbag can be pumped back and forth in a simple manner between the airbag and the accumulator. This saves the air drying effort if ambient air is used as the gas. Optionally, part of the gas can also be stored in air cushions when the airbag is not inflated.

With the features of claim 16 it is achieved that the mechanism for extending and retracting the flat outer skin part or an airbag provided is effectively protected against contamination. Claim 17 characterizes an embodiment of the motor vehicle which can be constructed inexpensively as a compact vehicle for a wide variety of uses and at the same time has a high level of safety. The impact protection module can be a completely separate unit that is adapted to the respective requirements and the permissible costs.

Claim 18 characterizes a particularly advantageous embodiment of the vehicle, in which, in addition to the "braking path" possible for the vehicle occupant due to the extendable outer skin part, the path by which the seat can be displaced in the event of a crash is used to improve safety that the passenger sitting on it is endangered.

With the features of claim 19, a targeted slackening of the seat belt is additionally used for "braking" the occupants.

With the features of claims 18 and 19, if a sufficiently long braking distance is achieved, the bumper plate can be dispensed with entirely.

The invention is explained below with reference to schematic drawings, for example and with further details.

They represent:

1 is a side view of a compact vehicle,

2 shows a detailed view of a front bumper plate in the extended (a)) and retracted (b)) position,

3 shows an embodiment of the bumper plate according to FIG. 2 equipped with an air bag, 4 schematically shows the course of an impact with an obstacle of a vehicle according to FIG. 3,

5 different embodiments of a mechanism for extending a flat outer skin part,

6 sectional views of a vehicle door equipped with an extendable outer skin part,

Fig. 7 is a sectional view of a tailgate equipped with an extendable outer skin part and

8 shows a compact vehicle constructed in a modular design.

1 shows a side view of a compact vehicle, which differs from previously conventional vehicles primarily in that its base area largely corresponds to the usable area. This can be achieved, for example, by an underfloor construction in which all of the essential units are located below the interior or useful space of the vehicle. Furthermore, the vehicle occupants sit in a relatively upright position, which makes the vehicle tall and short compared to conventional vehicles. In this construction, but also in the construction of conventional vehicles, which is directed towards the smallest possible footprint, the dimensions of the crumple zones available outside the passenger compartment or usable space are extremely limited. Such crumple or deformation zones are necessary in order to slow the occupant (s) so slowly in the event of a vehicle impact that there is a chance of survival or the severity of injury is reduced accordingly. For this purpose, the vehicle is equipped on its front area and optionally also on the side doors in the areas below the windows and in its rear area with extensible, flat outer skin parts 8, 10 and 12. At the front of the vehicle, the extensible, flat outer skin part advantageously includes the bumper with its apron and extends to the lower edge of the windshield 14, so that it forms an overall bumper shield. Depending on the design and design, the vehicle headlights 15 are held on the bumper plate 8 with integrated turn signals or on a fixed body part.

In the area of the doors, the extendable outer skin parts 10 form large-area components of the outer door panels or panels, or the entire relevant parts.

In the rear area, the flat outer skin part 12, like the front bumper plate 8, forms a rear label that extends below a luggage loading edge of the vehicle.

It goes without saying that, depending on the design effort and requirements, a wide variety of images and sizes of the extendable flat outer skin parts are possible. In particular, the laterally extendable outer skin parts in the area of the side doors, and in particular in the case of 2-door vehicles, the side body parts can advantageously be designed in such a way that they also influence the stylistic impression of the vehicle, for example by emphasizing the fact that the sides or all-round bumper strips etc.

According to FIG. 2a, the front bumper plate 8 is guided in a longitudinally displaceable manner in longitudinal members 18 of the very rigid vehicle structure via guide parts 16. For moving the bumper plate 8, hydraulic cylinders are advantageously accommodated in the longitudinal beams 18 and, when appropriately controlled, move the bumper plate 8 into an extended position (FIG. 2a) or a retracted position (FIG. 2b).

The guide parts 16 are rigidly connected to a front bumper, not shown, hidden under the bumper plate 8, so that a stable substructure is created. The structure of the bumper itself can be known so that it is not described in detail. is refined. The bumper apron is advantageously formed in one piece with the large bumper plate 8 with the front end of the body.

So that the large-area bumper plate 8 is stably guided on the one hand and on the other hand can be optimally used for energy absorption in the event of an accident, struts 24 and 26 are advantageously mounted on its rear side in upper bearings 20 and lower bearings 22. In the area of the rigid front body structure 28 there is a spindle drive 34, known per se and driven by an electric motor 32, the threaded spindle 36 of which is in screw engagement with an upper and lower strut 24 and 26, respectively.

In the position according to FIG. 2a, the spindle-side ends of the struts 24 and 26 are moved into end positions that are spaced apart from one another, in which they are directly adjacent to node structures of the body structure 28, so that they act stably on the body structure 28 when a force acts from the front support.

The bearings 20 and 22 are attached to an inner frame of the bumper plate 8.

Overall, the design of the vehicle front according to FIG. 2a, in which the bumper plate 8 is extended, for example, by approximately 40 cm, represents an extraordinarily effective crumple zone. In the event of a collision with an obstacle to the left of the vehicle front according to FIG. 2a, the impact forces become Introduced from the bumper plate 8 into the body structure 28 via the guide parts 16, the slightly oblique lower struts 26 and the possibly also slightly oblique upper struts 24. The struts 24 and 26 are designed, for example, as inverted tubes or buckling supports, so that they deform in a targeted manner while absorbing energy. The hydraulic cylinders (not shown) provided for moving the guide parts 16 in the side members 18 are constructed via pressure relief valves with a variable cross section or overflow openings so that they also break down energy in a defined manner when the guide parts 16 move into the side members 18. The bumper plate 8 advantageously has a somewhat resilient surface, so that the severity of injuries in pedestrian accidents is reduced.

2b shows the spindle drive 34 in the position in which the struts 24 and 26 are "drawn in" by the threaded spindle 36, so that the bumper plate 8 is in the retracted position flush with the vehicle.

The control of the entire arrangement is advantageously such that the bumper plate 8 is retracted when the vehicle is stationary, that is to say in particular parked, and is moved out of the vehicle as soon as it is driving faster than a defined speed. A wide variety of activation principles are conceivable, for example by means of sensors which determine the speed, the running engine, the closed vehicle door, a person on a seat, etc. The bumper plate 8 or the crumple zone is advantageously always activated when the vehicle is not parked. The driver can also control the extension and retraction of the bumper plate at the push of a button.

In the case of a somewhat modified embodiment of the device described, it is sufficient to use only the electric motor (s) 32 for extending and retracting, so that the guide parts 16 in the side members 18 are only moved passively. The guide parts 16 are guided in the longitudinal beams 18 in hydraulic cylinders with a variable overflow cross-section, so that a targeted energy reduction takes place in the event of an impact.

Alternatively, the extension and retraction of the bumper plate 8 can also take place only via hydraulic cylinders between the guide parts 16 and the longitudinal members 18 and the struts 24 and 26 are moved passively by mounting them on the bumper plate 8 or on the body structure 28 and are guided on the respective other component and passively move in the guides when the bumper plate 8 is extended or retracted.

The bumper plate 8 can also be reduced again manually by foot or hand control extended and retracted.

FIG. 3 shows a development of the embodiment according to FIG. 2, in which an airbag 38 is arranged between the bumper plate 8 and the body structure 28. A line 40 with a valve 42 is provided for inflating the airbag. The airbag 38 advantageously consists of a plurality of chambers, not shown, which are provided with overpressure valves or specifically with throttle openings and / or outflow openings which open at a certain overpressure, so that the airbag 38 is effective for reducing energy in the event of an accident contributes.

Advantageously, the inside of the airbag 38 is connected via an overflow line 44 to an air cushion 46 which is arranged in the interior of the vehicle and inflates in a flash in the event of an accident, so that the airbag 38 is reduced in size as a result of the push plate 8 being pushed back. This reduction is associated with a large change in volume compared to the volume of the air cushion 46, which leads to a rapid overflow of air and thus an inflation of the air cushion 46 when the air pressure 38 is sufficiently high. Depending on the pressure that is set in the normal, extended state of the bumper plate 8 in the airbag 38, an electrically controlled valve 48 can be provided in the overflow line 44, which opens the overflow line 44 in the event of a crash. It goes without saying that a plurality of air cushions arranged at exposed points in the interior can be provided.

3a schematically shows the airbag 38 in the retracted state of the protective shield 8.

FIG. 4 shows the arrangement according to FIG. 3, installed in a compact vehicle, the air cushion 46 being a steering wheel airbag. The compact vehicle is shown with a largely removed body and has a mobile basic module 50, to which the bumper plate 8 with the air bag 38 and the associated guide or removal mechanism (not shown) for the bumper plate 8 are attached. In the basic module 50 are the drive of the vehicle, steering, pedal group, etc. arranged. Furthermore, a driver's seat 52 is shown, which is held on the basic module in a longitudinally displaceable and stable manner by means of guides, not shown. The seat 52 is normally in the rearmost position, into which it is pressed by the force of a spring 54. When the spring 54 is compressed during a forward movement of the driver seat 52 relative to the basic module 50, a damping device (not shown) in the manner of a shock absorber is effective, which dampens the relative movement, converts energy and prevents rebounding.

An operator 56 is held in the driver's seat 52 by means of a seat belt 58, which deliberately releases a little under load.

To protect the operator 56 and the entire vehicle interior, a stable and rigid roll bar 60 is rigidly connected to the basic module 50.

4a shows a situation in which the vehicle strikes a rigid obstacle 62 coming from the right: the airbag 38 is filled with gas, the valve 48 is closed and the air cushion 46 is empty. The driver's seat 52 is in its rearmost position and the operator 56 is held in contact with the driver's seat 52 by the seat belt 58.

In the situation according to FIG. 4b, the vehicle has moved to the left by the distance b. The bumper 8 has already moved this distance to the basic module 50, so that the airbag 38, which resembles an accordion, is reduced in size. Due to the high overpressure arising in the overflow line 44, the valve 48 has opened and the air cushion 46 has already been largely inflated. The driver seat 52 has moved forward by the distance b, against the force of the spring 54 and the fluid damping relative to the basic module 50. As a result of its inertia, the operator 56 pulls heavily on the seat belt 58, which deliberately lengthens a little, and the operator 56 moves forward a distance can win from the driver's seat 52. Overall, the distance by which the operator 56 has moved forward relative to the state is b plus b _j plus the distance of the operator 56 from the driver's seat 52. The abrupt braking of the bumper plate 8 is converted into a soft braking of the operator 56 .

In state c) the deformation path of the bumper plate 8 is almost completely absorbed, since the vehicle has moved the distance c) in the direction of the obstacle 62. The air cushion 46 is fully inflated. The operator 56 has moved forward together with the seat by the distance b ₂ relative to the basic module 50 and is held at a distance from the driver's seat 52 by the seat belt 58. In addition, the air cushion 46 counteracts a further movement of the operator 56, in particular preventing the head from nodding forward.

Overall, the arrangement described ensures that even serious accidents can be survived more easily.

5 shows in a) a mechanism in which the struts 24 and 26 of FIG. 2 are replaced by scissors 64 and 66, which in turn are moved via a spindle drive 68. The ends of the scissors 64 and 66 opposite the spindle drive 68 are guided in guides relative to the movable, flat outer skin part 70. Depending on the design, image a) represents a top view (the scissors 64 and 66 are located side by side within a plane) or a side view (the scissors 64 and 66 are located one above the other and form two different levels, in which the outer skin part 70 is supported on the body structure 72). The scissor mechanism according to FIG. 5a keeps the flat outer skin part 70 stable on the one hand and on the other hand serves to effectively dissipate energy when deformed.

5b shows a mechanism in which the scissors 64 and 66 are each replaced by double struts 74 and 76 which are articulated on one side to the flat outer skin part 70 and cooperate with the spindle drive 68 at their other ends. Figure c) shows the outer skin part 70 in its retracted position flush with the body.

6 shows the design of a vehicle door with an outer skin part 10 which can be extended to increase the side impact safety. The vehicle door has a door body 78 into which a side window 80 can be lowered. In a manner known per se, the door body is formed with an upper side member (not shown) and is supported at the bottom on a vehicle sill of high stability. The outer skin part 10 is movable relative to the door body 78 via a circumferential flange 82, which cooperates with a corresponding circumferential outer surface 84 of the door body 78, and any additional guides that may be present. An airbag 86, the connections of which are not shown, is arranged between the door body 78 and the outer skin part 10. The airbag 86 is glued to the outer skin part 10 and the door body 78 so that the outer skin part 10 moves into its extended position b) when the airbag 86 is inflated and into its retracted position a) when subjected to negative pressure. For the targeted introduction of force when the outer skin part 10 is subjected to a force according to FIG. 5b on the left 78 support parts 88 and 90 are mounted on the top and bottom of the door body. The bearing is, for example by means of springs (not shown) enclosing the bearing axles, in such a way that the upper support part (s) 88 are elastically biased clockwise and the support part (s) 90 are biased counterclockwise, so that when they are removed move the outer skin part 10 from the position shown in FIG. 5a automatically into the position shown in FIG. 5b and move in the opposite direction when retracting.

It goes without saying that the outer skin part 10 has a deformation-resistant structure, in the case of deformation itself an energy-absorbing structure, for example a deliberately ribbed sandwich structure.

The support parts 88 and 90 can alternatively also be designed such that when the airbag 86 is inflated from it into the active position and back into the retracted position Position are moved.

With the design described, a certain crumple zone is achieved even in the event of a side impact, without the door thickness or vehicle width being increased when the vehicle is parked. In vehicles parked side by side, every unnecessary centimeter of door thickness or vehicle width is a hindrance because of the door opening required for getting in and out.

FIG. 7 shows an embodiment very similar to that of FIG. 6 on a tailgate of a vehicle. The tailgate 92 has a flap body 94 and an outer skin part 96 which engages via a circumferential flange 94 in a corresponding circumferential groove 100 of the flap body 94. The mechanism for extending the outer skin part 96 relative to the flap body 94 corresponds to the arrangement according to FIG. 6, so that it will not be discussed further. In the extended state, the outer skin part 96 is supported on a longitudinal structure 102 of the vehicle body in the event of a force acting from behind (from the left according to FIG. 7) because of the overlapping arrangement of the tailgate 92.

The flap is articulated at 92 on the IL 102 system about a horizontal axis so that it can be opened in the counterclockwise direction according to FIG. 7 and then simultaneously forms a storage surface.

Alternatively, the flap can also be articulated laterally so that it can be pivoted about a vertical axis.

It goes without saying that the rear area of the vehicle can be designed analogously to the front area, so that the rear bumper together with a rear end part forms a bumper plate which can be extended to the rear.

This bumper plate then extends up to the lower edge of the luggage flap. At a In such an embodiment, the loading edge of the vehicle is somewhat above the height of the bumper. However, an extremely accident-proof design of the rear of the vehicle is achieved. The somewhat higher loading edge can also be accepted because the rear of the compact vehicle is very short.

The support of the extended, flat outer skin part on the body structure via the support parts or struts is advantageously such that the support parts or struts run essentially in the direction of the force flow in which the collision forces are introduced from the outer skin part into the rigid body structure in the event of a collision.

8 illustrates an example of the modular structure of a vehicle according to the invention, a) in the assembled state and b) in an exploded view.

The basic module 50 (FIG. 4) comprises a front module 104 with the front wheels, the steering, the foot pedal group and the front seats as well as the roll bar 60. The rear module 106 comprises the rear wheels, rear axle, coupling device for the front module, for example Schwalbeiischwairzfiihrungen, etc. Each after the drive (rear-wheel drive, front-wheel drive, electric motor, internal combustion engine, hybrid drive, etc.), the drive is located in the front module and / or rear module. The windshield 14 is attached to the Uberro bracket 60. Below the windshield 14, an impact protection module 108 with the bumper plate 8 is attached to the front module 104. Similar impact protection modules can be formed on the rear module 106 and the side areas of the vehicle. Each Au impact protection module is advantageously constructed so that it contains a base part attached to the stable, non-deformable vehicle module, which cooperates with the respective extendable, flat outer skin part in the manner of a box. The extension mechanism, for example in the form of a scissor mechanism with an additional air cushion, is arranged between the two parts.

As already mentioned, the airbag can consist of individual chambers which are arranged one behind the other. others, one chamber through the other or parallel to one another, connected to a gas source. Depending on the design of the connection between the individual air chambers, these can be filled in succession when arranged one behind the other, throttle openings or valves opening at certain pressures can be provided between the chambers. In addition, if necessary, each chamber can be provided with overpressure openings which open directly to the outside. It is particularly advantageous to connect the chambers in parallel to one another with a gas source, a control valve being arranged in each line and being controlled by an electronic control device. In this way, the filling of the entire airbag and thus its deformation behavior can be specifically adapted to the respective requirements.

The impact protection modules can be designed so that they can be used for different vehicles and can be retrofitted to them with appropriate construction. Such impact protection modules, which then have a structure that can be attached to the vehicle and that supports the extendable outer skin part with the associated mechanism and the energy absorption device, can be used for a wide range of vehicles, such as cars, commercial vehicles, mobile homes, trailers, etc.

Claims

Expectations

1. Motor vehicle, in particular a compact vehicle, with a body structure which is designed to be rigid and which is rigid in itself and which supports flat outer skin parts, and with an impact protection unit by means of which a vehicle part can be moved from a retracted position to an extended position which enlarges the vehicle base area, wherein the extended vehicle part reduces the deceleration of the useful space when it collides with an obstacle due to its movement in the direction of the vehicle, characterized in that the extendable vehicle part is a flat outer skin part (8, 10, 12; 70; 96).

2. Motor vehicle according to claim 1, characterized in that when the flat outer skin part (8, 10, 12; 70; 96) is retracted, the base area of the usable space is substantially equal to the base area of the motor vehicle.

3. Motor vehicle according to claim 1 or 2, characterized in that the flat outer skin part (8) comprises the front bumper of the vehicle and at least a large part of a part forming the front of the vehicle, from the bumper to the lower edge of the windshield (14) extending part .

4. Motor vehicle according to one of claims 1 to 3, characterized gekenn¬ characterized in that the flat outer skin part is the outer part (10) of a side vehicle door or a body side part.

5. Motor vehicle according to one of claims 1 to 4, characterized gekenn¬ characterized in that the flat outer skin part (12; 96) forms at least a part of the rear body end.

6. Motor vehicle according to one of claims 1 to 5, characterized - is characterized in that the extendable flat outer skin part (8, 10, 12; 70, 96) extends in the extended state at least in two planes via selectively deformable support parts (16, 24, 26; 64, 66; 74, 76; 88, 90 ) is supported on the body structure.

7. Motor vehicle according to claim 6, characterized in that the effective in an upper level support parts are formed by movable struts (24) which support the flat outer skin part in its extended position on a rigid body part (28).

8. Motor vehicle according to claim 6 or 7, characterized in that at least some of the support parts (16, 24, 26; 64, 66; 74, 76; 88, 90) in the extended position of the flat outer skin part substantially in the direction of the force flow resulting in the event of an impact on an obstacle.

9. Motor vehicle according to claim 7 or 8, characterized in that the flat outer skin part (8) is linearly movable in a lower plane relative to the vehicle, and that the movable struts (24) of the upper level by the movement of the flat outer skin part (8) can be brought passively from a rest position into an active position.

10. Motor vehicle according to one of claims 1 to 9, characterized gekenn¬ characterized in that an airbag (38; 86) is arranged between the flat outer skin part (8, 10) and the vehicle body, which degrades at least part of the impact energy .

11. Motor vehicle according to claim 10, characterized in that the air bag (38) is connected to at least one further, in the interior of the vehicle angeord¬ net air cushion (46) which is inflated by the air escaping from the air bag upon impact .

12. Motor vehicle according to claim 10 or 11, characterized gekennzeich¬ net that the extension or retraction of the flat outer skin part is carried out by acting on the air bag (38; 86) with positive or negative pressure.

13. Motor vehicle according to one of claims 10 to 12, characterized gekenn¬ characterized in that the pressure of the gas in the airbag (38) contained gas is extensible with extended flat outer skin part (8).

14. Motor vehicle according to one of claims 10 to 13, characterized in that the airbag consists of several chambers which are provided with valves opening at different pressures.

15. Motor vehicle according to claim 14, characterized in that the chambers are connected via valves to a pressure source and a pressure control device is provided for controlling the valves.

16. Motor vehicle according to one of claims 1 to 15, characterized gekenn¬ characterized in that the flat outer skin part (10; 96) has a circumferential flange (82; 98) which in the retracted state of the flat outer skin part a corresponding body-fixed flange (84; 100 ) overlaps.

17. Motor vehicle according to one of claims 1 to 16, characterized gekenn¬ characterized in that it is modular in design with the following modules: a) a mobile basic module (50), which forms the usable surface of the motor vehicle on its top, a drive with the associated supply devices contains and has a roll bar (60), b) at least one impact protection module (108) at the front of the basic module (50), which is the front bumper and at least a large part of a part forming the front of the vehicle and extending from the bumper to the lower edge of the windshield as extendable, flat outer skin part, and c) a build-on module that can be placed on the basic module.

18. Motor vehicle according to one of claims 1 to 17, characterized - I ne t that a seat (52) attached to the deformation-resistant body structure in the usable space is normally pressed into a rearmost position by a resilient device (spring 54) and in the event of an impact of the motor vehicle on a front

Obstacle (62) can be moved forward by a predetermined distance (b ₂ ).

19. Motor vehicle according to one of claims 1 to 18, characterized gekenn¬ characterized in that a on a vehicle seat (52) attached seat belt (58) a person sitting on the vehicle seat in the event of an impact on an obstacle (62) releases a predetermined distance.