DE102004009766B4 - Vehicle safety device with at least one actuator for moving a component of the outer skin of the vehicle - Google Patents

Abstract

Vehicle safety device (10) with at least one actuator for lifting a hood (12) of a motor vehicle over a predefined path length (X), wherein the actuator is dimensioned such that the motor hood (12) by a movement of the actuator only over a partial distance ( A) of the predefined path length (X) can be accelerated and subsequently the remaining part of (B) can overcome the entire predefined path length (X) due to their inertia, wherein the vehicle safety device (10) at least one holding element for supporting the hood (12) in the actuator comprises a plunger (16) for moving the member (12), a guide (20) for movably supporting the plunger (16) and a pressure accumulator (22) for moving the plunger (16) is designed, and the plunger (16), the guide (20) and the pressure accumulator (22) are dimensioned such that the component (12) by moving the plunger (16) can be accelerated over the partial section (A) of the predefined path length (X), whereby the partial section ...

Description

Background of the invention

The invention relates to a vehicle safety device having at least one actuator for moving a component of the outer skin of the vehicle in a passenger impact over a predefined path length, in particular for lifting a hood of a vehicle over this predefined path length.

When constructing and designing modern vehicles or automobiles, great importance is attached to ensuring that, in the event of an accident, a person hitting the outer skin of the vehicle remains as unhurt as possible. A particular danger is in such an accident, the impact of the person with his head on the outer skin of the vehicle involved in the accident. This danger, for example, when a pedestrian, a cyclist or motorcyclist is detected by a vehicle and the head of the accident participant against The hood of the accident vehicle is thrown.

In modern vehicles, in particular between the hood and an underlying drive unit, such as an internal combustion engine, no sufficient space for a sufficiently large deformation of the hood available. There is therefore a great risk that an impacting head experiences a high biomechanical load and "strikes" the drive unit. To assess such a risk of "beating through" an impacting head, so-called HIC values are determined in test series, by means of which the biomechanical load can be classified.

As a possibility of improved personal protection, it is known to raise the hood or front door of a vehicle by several centimeters, as soon as an accident is detected with a possible collision. By raising the hood of the distance is increased to an underlying unit and also generated by the additional movement of the hood and the associated spring forces and inertia energy reduction over a relatively large way. The level of deceleration thus achieved for an impacting person's head thus drops to a biomechanically more tolerable value, and a "strike-through" to a highly rigid drive unit located under the engine hood in the front of the vehicle is prevented.

From the DE 101 36 340 A1 a vehicle safety device is already known with at least one actuator for lifting a hood of the vehicle in a passenger impact over a predefined path length.

Underlying task

The invention has for its object to improve a vehicle safety device of the type mentioned in particular with regard to the energy required for it, while the cost and the production cost of the vehicle safety device should be reduced as possible.

Inventive solution

The object is achieved according to the invention with a generic vehicle safety device in which the actuator is dimensioned such that the component can be accelerated by a movement of the actuator only over a portion of the predefined path length and subsequently overcome the remaining portion of the entire path length due to its inertia can.

According to the vehicle to the moving component of the outer skin, the hood of a motor vehicle, accelerated only over a certain distance and then the component according to the momentum conservation of its own inertia is left, which means that the component is a further leg without acceleration or with a slight deceleration due to air friction overcomes. In this way, the component to be moved is moved over a predefined path length overall with comparatively little labor or energy expenditure, and, moreover, a movement behavior of the moving component is generated, which is particularly advantageous in the event of a collision with a person.

According to the invention, namely due to the air friction of the component whose speed near the end of the predefined path length is comparatively low, so that the moving component z. B. approaching a head striking it at a comparatively slow speed. This behavior of the moving component is advantageous in particular with regard to the then acting on the head biomechanical forces.

In addition, the actuator according to the invention is particularly suitable and provided for a vehicle safety device, which is reversible after moving a component of the outer skin of a vehicle and, for example, to be moved back by a user of the vehicle to its original position. Such a backward movement requires that in the actuator, the acceleration energy exerted by him on the component again manually is introduced. Since comparatively little acceleration energy has to be applied in the actuator according to the invention in order to accelerate the component over the limited path, only comparatively little energy needs to be introduced for the return of the actuator. The vehicle safety device according to the invention can therefore be reset relatively easily by means of a restoring device provided there. The resetting is for example possible by a raised hood completely opened by the user of the vehicle and subsequently closed again.

The actuator of the vehicle safety device according to the invention is particularly cost-effective by means of a plunger, a guide and a pressure accumulator designed such that the component is accelerated by moving the plunger over the leg of the predefined path length.

For the lifting of a hood of a motor vehicle, it is particularly advantageous if the hood is raised within a total time of about 40 to 60 ms while using the plunger, the hood "only" over a period of about 20 to 40 ms, in particular of About 30 ms from the actuator or plunger of the vehicle safety device according to the invention can be accelerated.

Furthermore, it is advantageous if the engine bonnet to be lifted is moved in total over a predefined path length of approximately 40 to 80 mm and, for this purpose, the engine bonnet can be accelerated by the actuator or tappet over a partial distance of approximately 20 to 40 mm, in particular approximately 26 mm is.

With regard to the maximum compressive force generated by the actuator or ram, the vehicle safety device provided for lifting an engine hood should produce a maximum of approximately 700 to 900 N, in particular approximately 800 N.

Based on this maximum pressure force, it is particularly advantageous if the pressure accumulator has a substantially linearly sloping spring characteristic. The moving component of the outer skin of the vehicle is accelerated at such a linearly decreasing spring characteristic with increasing distance always weaker, so that the transition to the unaccelerated, free movement of the component can be flowing solely due to its inertia. A linearly decreasing spring characteristic can be provided particularly advantageously with the aid of a helical spring as an accumulator or with a gas pressure accumulator. As an alternative or in addition to such an accumulator, a pyrotechnic energy dispenser, for example in the form of an airbag, may be provided for the actuator, which by way of its extension moves the component of the vehicle skin over the partial path of the entire predefined path length.

So that an engine hood of a motor vehicle can be moved sufficiently accurately and uniformly in its entirety in the case of a personal accident, four actuators or plungers according to the invention, each with an associated guide and an associated pressure accumulator, should be provided on it. The actuators or plunger should be triggered simultaneously, which is possible for example by coupling the respective release mechanism provided by means of Bowden cables.

Furthermore, at least one support element for holding the engine hood in the raised position and / or a retaining hook, in particular a conventional engine hood lock, by means of which the predefined path length of the lifting of the engine hood is limited to the desired maximum value and also held, must be provided on the engine hood can. In the case of triggering the vehicle safety device according to the invention then z. B. first solved the lock and accelerates the hood by means of the actuator over the leg of the predefined total path length. Subsequently, the hood covers the remaining leg of the entire distance due to their inertia, until it is stopped by the retaining hook of the hood lock.

At about the time of this "catching" the hood with the help of the hood lock in a collision at the front of the vehicle, the head of the impinging person hit the then raised hood, thereby ensuring that the head can deform the hood comparatively far without on to encounter a drive unit arranged thereunder.

Brief description of the drawings

Hereinafter, an embodiment of a vehicle safety device according to the invention will be explained in more detail with reference to the accompanying schematic drawings. It shows:

1a a side view of an embodiment of a vehicle safety device according to the invention in the biased and locked position of an associated actuator,

1b the view according to 1a during an extension movement of the plunger,

2 the view according to 1a with a fully raised bonnet,

3a the view according to 1a with a locked lock arranged on the vehicle safety device,

3b the view according to 3a with the lock in unlocked state and

4 a graphical representation of the course of the force of the actuator during a lifting of a hood.

Detailed description of the embodiment

In the 1a to 3b is a vehicle safety device 10 illustrated, by means of in the event of an accident on impact of a person on the associated motor vehicle whose hood 12 can be raised very quickly. With the bonnet raised 12 lies between this and an underlying drive unit 14 a greater distance before, so that a penetration of particular the head of the person involved in the accident on the drive unit 14 can be prevented.

The vehicle safety device 10 has as an essential component an actuator with an actuator 16 on, on an abutment 18 supported the chassis of the motor vehicle, not shown further and in also arranged on the chassis guides 20 slidably guided. The actor 16 is opposite the abutment 18 with the help of a pressure accumulator 22 supported in the form of a coil spring, which in the prestressed state an energy store for moving the plunger 16 forms. The accumulator 22 is designed and designed such that the plunger 16 40 ms over a distance of about 40 mm is moved and thereby generates a compressive force of about 800 N maximum.

So that the plunger 16 in the in 1a shown biased position is locked and still the vehicle safety device 10 can be triggered comparatively easily, is a locking device 24 provided, in particular with a pressure element 26 in the form of a pressure lever and a tension element 28 is formed in the form of a pull lever. The pressure element 26 is at a first joint 30 supported on the chassis and on a second joint 32 at its opposite end region with the tension element 28 articulated. This tension element 28 is in turn at the opposite end of a third joint 34 on the pestle 16 hinged.

In this way, with the pressure element 26 and the tension element 28 Overall, a toggle mechanism formed in which the pressure element 26 a shorter lever element and the tension element 28 form a comparatively long lever element. The levers of the toggle mechanism can be moved near a dead center, as in 1a is shown, and in this position have a comparatively low holding moment about the first joint 30 or the third joint 34 on. The pressure element 26 and the tension element 28 can therefore in this situation with relatively little effort from a rotary latch 36 be held lightly attached to the second joint 32 attacks.

The catch 36 is by means of a pawl 38 locked by an electromagnet 40 can be moved, causing the catch 36 and thus also the locking device 24 is released.

By the pivoting catch 36 the second joint 32 releases, the pressure element rotates 26 towards the hood 12 and the likewise moving tension element 28 leaves the pestle 16 towards this bonnet 12 move. The in the accumulator 22 stored energy pushes the pestle 16 with high force against the bonnet 12 which accelerates by and from the power plant 14 is moved away.

With the movement of the hood 12 increases the distance between the drive unit 14 and the hood, which ensures that one during an accident on the hood 12 striking head of a person involved in the accident does not experience dangerously high biomechanical loads.

So that the hood 12 can be moved over a comparatively long path length X and this can still happen with a comparatively small designed and therefore comparatively inexpensive safety device are the plunger 16 , the leadership 20 and the accumulator 22 such that the bonnet 12 by the movement of the plunger 16 is accelerated only over a first section A of the predefined path length X. This leg A is the track within which the tappet 16 fully extended. Subsequently, the hood overcomes 12 a remaining section B of the entire predefined path length X according to the momentum conservation due to their inertia. This type of acceleration and subsequent movement of the hood 12 is in 2 starting from the rest position of the engine hood shown in dashed lines 12 again especially illustrated.

So that the hood 12 but not being raised beyond the predefined path length X, is an in 3b illustrated retaining hook 42 on the hood 12 provided with a fixedly attached to the chassis of the vehicle hook 44 interacts. When fully raised or raised hood 12 arrives the retaining hook 42 engaged with the hook 44 and thus prevents further lifting of the hood 12 , In such a raised position, the hood is further held by a support spring, not shown, as such only for supporting the hood 12 and essentially not as an actuator for accelerating the hood 12 acts. To open the bonnet 12 may be the engagement of the two elements 42 and 44 be solved manually.

In the 3a and 3b It also illustrates that it is right next to the actor 16 the vehicle safety device 10 a castle 46 located with the hood 12 is held in the properly closed state. The castle 46 is with a lock hook 48 provided by a rotary latch 50 is locked. Between the catch 50 and the pestle 16 is an angle lever 52 provided by a movement of the plunger 16 is pivoted and by this pivoting movement then the catch 50 releases. When turning the catch 50 becomes the lock of the lock hook 48 solved and thus the lock 46 opened, leaving the hood 12 as intended, at least the predetermined path length X can move upwards.

In the 4 the course Y of a force F over the path length X is shown, which during the extension of the plunger 16 over the section A away from the pressure accumulator 22 is produced. The force F acts on the bonnet 12 , Below is the plunger 16 limited in its upward movement and the hood 12 Due to the pulse transmitted to it, the remaining section B still moves upward until it has reached the total path length X. In this raised position is the hood 12 held by the support spring, not shown.

To reset the plunger 16 In its initial position, the work which must be applied as an integral below the force-displacement curve Y in FIG 4 to recognize and represented as hatched area. This work can for example be applied by the bonnet 12 is fully opened and then when closing the hood 12 a restoring device with a gear is set in operation, which generates a comparatively large path length, which is in particular greater than the path length X, only a comparatively small force.

Overall, according to the invention, the work to be produced (hatched area) for the return relatively small, because the inventively raised bonnet 12 is during lifting through the pressure accumulator 22 only partially accelerated, so that only the work generated thereby must be reset.

LIST OF REFERENCE NUMBERS

10

Vehicle safety device

12

Engine Hood

14

Drive assembly

16

tappet

18

abutment

20

guide

22

accumulator

24

locking device

26

pressure element

28

tension element

30

first joint

32

second joint

34

third joint

36

catch

38

pawl

40

electromagnet

42

Retention hook

44

hook

46

lock

48

Castle hook

50

catch

52

bell crank

X

entire predefined path length

A

first leg

B

second leg

Y

Force-displacement curve of lifting

Claims (7)

Vehicle safety device ( 10 ) with at least one actuator for lifting a hood ( 12 ) of a motor vehicle over a predefined path length (X), wherein the actuator dimensioned in such a way is that the hood ( 12 ) can be accelerated by a movement of the actuator only over a partial section (A) of the predefined path length (X) and subsequently the remaining section (B) of the entire predefined path length (X) can overcome due to their inertia, wherein the vehicle safety device ( 10 ) at least one retaining element for supporting the hood ( 12 ) in the raised position in the form of a support spring, and wherein the actuator with a plunger ( 16 ) for moving the component ( 12 ), a guided tour ( 20 ) for movably supporting the plunger ( 16 ) and a pressure accumulator ( 22 ) for moving the plunger ( 16 ), and the plunger ( 16 ), the leadership ( 20 ) and the accumulator ( 22 ) are dimensioned such that the component ( 12 ) by moving the plunger ( 16 ) can be accelerated over the sub-section (A) of the predefined path length (X), the sub-section (A) being the section within which the ram ( 16 ) is fully extended. Vehicle safety device according to claim 1, characterized in that this for raising the hood ( 12 ) of the motor vehicle within a total time of between about 40 and 60 ms is provided and the actuator is dimensioned such that the hood ( 12 ) can be accelerated over a period of between about 20 and 40 ms. Vehicle safety device according to one of claims 1 to 2, characterized in that this for lifting the hood ( 12 ) of the motor vehicle over a predefined path length (A) of between about 40 and 80 mm is provided and the actuator is dimensioned such that the hood ( 12 ) over a partial distance (B) of between about 20 and 40 mm from the actuator can be accelerated. Vehicle safety device according to one of claims 1 to 3, characterized in that this for lifting the hood ( 12 ) of the motor vehicle is provided and the actuator is dimensioned such that the hood ( 12 ) with a maximum compressive force of between about 700 and 900 N can be accelerated. Vehicle safety device according to one of claims 1 to 4, characterized in that the actuator with a pressure accumulator ( 22 ) is designed, which has a substantially linear sloping spring characteristic. Vehicle safety device according to one of claims 1 to 5, characterized in that this for lifting the hood ( 12 ) of the motor vehicle is provided and a total of four actuators are provided. Vehicle safety device according to one of claims 1 to 6, characterized in that this for lifting the hood ( 12 ) of the motor vehicle is provided and at least one retaining hook ( 42 ) is provided by a conventional bonnet lock, by means of which the predefined path length (X) of the lifting of the hood ( 12 ) is limited.

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