Vehicle occupant restraint system with adaptive knee airbag
Patent Information
- Authority / Receiving Office
- DE · DE
- Patent Type
- Patents
- Current Assignee / Owner
- ZF AUTOMOTIVE GERMANY GMBH
- Filing Date
- 2012-06-05
- Publication Date
- 2026-07-23
Smart Images
Figure 00000000_0000_ABST
Abstract
Description
[0001] The invention relates to a vehicle occupant restraint device with an inflatable knee airbag. The invention also relates to a method for protecting a vehicle occupant.
[0002] The inflation and outflow behavior of airbags is tested with crash test dummies in impact tests. Crash test dummies are life-size dolls that are modeled on the human body. In order to take the different anatomical conditions of real people into account in the simulations, the tests are usually carried out with three different dummies: The "50 percent man" with a height of 175 cm and a weight of 78 kg should generally have a " "normal" tall vehicle occupant, the "95 percent man" with a height of 188 cm and a weight of 101 kg corresponds to a tall vehicle occupant and the "5 percent woman" with a height of 152 cm and a weight of 54 kg a small vehicle occupant. Due to the different physiques, the normal seating positions of the various dummies and the distances between certain body parts and the surrounding vehicle components vary accordingly in the crash test attempts.
[0003] In modern vehicle safety systems with airbag modules, efforts are being made to adapt the safety system more and more individually to various parameters of a crash situation. A well-known and advantageous option is the use of traction devices such. B. tethers, the release of which opens or closes the outflow openings of the gas bag. With such traction means, the gas bag geometry can also be influenced and / or an additional gas bag volume can be released. Activation units are known for this purpose, e.g. B. under the acronym "TAU" (Tether Activation Unit), with which the release of tethers can be actively controlled. Gas bag modules with such activation units are known, for example, from DE 10 2008 028 921 A1 or DE 10 2009 005 771 A1.
[0004] The object of the invention is to enable the protective effect of an inflated knee airbag to be adapted to the physique of a vehicle occupant.
[0005] This object is achieved by a vehicle occupant restraint device having the features of claim 1. Advantageous and expedient refinements of the vehicle occupant restraint device according to the invention are specified in the associated subclaims.
[0006] The vehicle occupant restraint device according to the invention comprises a knee airbag that can be deployed between an instrument panel and the legs of a vehicle occupant, which knee airbag has an airbag casing and at least one outflow opening formed therein. The vehicle occupant restraint device also includes a device for qualifying the physique of the vehicle occupant, an activation unit for selectively releasing the outflow opening and a control device which actuates the activation unit as a function of the qualification of the physique of the vehicle occupant.
[0007] The invention is based on the basic idea that an improved protective effect, especially in the lower half of the body, can be achieved by passively adapting the knee gas bag internal pressure to the physical constitution of the respective vehicle occupant. The control device provided according to the invention, together with the activation unit, ensures that the outflow opening is opened or blocked depending on the physique of the vehicle occupant, in particular the body size and / or weight. If a small vehicle occupant is detected beforehand, the outflow opening can be released in order to dampen the impact on the knee airbag, whereas in the case of a normal-sized vehicle occupant the outflow opening is blocked so that the internal pressure in the airbag remains at a high level for longer. This means that the same amount of gas can always be used to inflate the knee airbag, regardless of the constitution of the vehicle occupant, since the internal pressure is automatically adjusted. A multi-stage gas generator is therefore not required for the solution according to the invention.
[0008] For the selective release of the outflow opening, a flap is suitable which covers the outflow opening on the inside, the flap being detachably fastened to the airbag casing, in particular by means of a tear seam. If necessary, the flap can be detached from the airbag jacket at least to the extent that gas can escape from the knee airbag through the outflow openings. The term "flap" is not to be understood in a restrictive manner, but rather includes a large number of possible forms and configurations. The at least partially detachable attachment to the airbag casing is essential.
[0009] According to the preferred embodiment of the invention, the flap is coupled to a traction device, which in turn is coupled to the activation unit. The traction mechanism is a suitable instrument for “actuating” the flap that covers the outflow opening as required, particularly when a small vehicle occupant is detected. If no actuation is desired, in particular if a (normal) large vehicle occupant has been detected, the activation unit releases the traction means so that the traction means cannot exert any force on the flap.
[0010] The length of the traction device should be dimensioned in such a way that the traction device is tensioned at the end of the deployment of the knee airbag and thereby at least partially detaches the flap from the airbag shell. This means that the traction device holds the flap while the upper gas bag section unfolds further. The flap is thus detached automatically, so that no additional measures are necessary to release the outflow opening.
[0011] Particularly effective, i. H. with comparatively little effort, the flap can be detached in a design according to which a seam, in particular a tear seam, divides the flap into an inner section covering the outflow opening and an outer section, and the traction means is connected to the outer section. With such a design, detaching the flap is comparable to removing a yoghurt lid.
[0012] This principle works best when the outer section, on which the traction mechanism acts, is guided over the inner section at an acute angle. Accordingly, the traction means should be arranged in the knee airbag in such a way that at the end of the unfolding process it forms an acute angle with the inner section of the flap, preferably in the range from 0° to 60°.
[0013] An arrangement of the outflow opening in the upper half, preferably in the upper third of the knee airbag, in relation to the usage position of the knee airbag, is particularly advantageous for the above-mentioned technical implementation with a traction mechanism if the preferred main direction of deployment of the knee airbag along the instrument panel (obliquely). above. In this case, no deflection measures or the like are necessary.
[0014] The object of the invention is also achieved by a method for protecting a vehicle occupant with the following steps: - qualifying the physique of the vehicle occupant; - Inflating a knee airbag which can be deployed between an instrument panel and the legs of a vehicle occupant and which has an airbag casing and at least one outflow opening formed therein, with gas; and - Adaptation of the gas outflow behavior by actuating an activation unit for releasing the outflow opening depending on the qualification of the physique of the vehicle occupant.
[0015] The advantages of the method according to the invention essentially correspond to those of the device according to the invention, so that reference can be made to the above statements.
[0016] When qualifying the physique of the vehicle occupant, a classification into one of the classes “small vehicle occupant” and “normally tall vehicle occupant” and / or “large vehicle occupant” preferably takes place, corresponding to the various dummy sizes used in typical crash tests.
[0017] According to the preferred embodiment of the method according to the invention, at the end of the deployment of the knee airbag, a traction means is tensioned, which is coupled to the activation unit on the one hand and to a flap covering the outflow opening on the other hand. As a result, the flap is at least partially detached from the outflow opening. The traction mechanism thus simply holds the flap while the upper gas bag section unfolds further, so that the flap is automatically detached.
[0018] Further features and advantages of the invention emerge from the following description and from the accompanying drawings, to which reference is made. In the drawings show schematically:
[0019] figure 1 shows a plan view of an expanded knee airbag for a vehicle occupant restraint device according to the invention;
[0020] figure 2 is a side sectional view of a vehicle occupant restraint device according to the invention during deployment of the knee airbag;
[0021] figure 3 is a side sectional view of the vehicle occupant restraint figure 2 after complete deployment of the knee airbag with released outflow opening;
[0022] figure 4 is a side sectional view of the vehicle occupant restraint figure 2 after full deployment of the knee airbag with blocked outflow opening and
[0023] figure 5 shows a side sectional view of the knee airbag in the area of the flap; and
[0024] figure 6 is a plan view of a flap attached to the knee airbag.
[0025] In figure 1 is a knee airbag 10 for a vehicle occupant restraint device from the point of view of the vehicle occupant to be protected in a state after being inflated by means of a gas generator from a housing 12 has unfolded out.
[0026] The knee gas bag 10 essentially consists of a gas bag shell 14 and shows connection points 16 for one or more internal safety straps. Also in the gas bag coat 14 one or more closely spaced outflow openings 18 formed by which, under certain circumstances, which will be discussed in more detail later, gas from the knee airbag 10 can escape. The outflow openings 18 are located, based on the in figure 1 usage position of the knee airbag shown 10 , in the upper half, more precisely in the upper third of the knee airbag 10 .
[0027] The outflow openings 18 are inside of a flap 20 covered in the form of a flexible fabric sheet or other non-dimensionally stable material. The flap 20 is on the inside of the gas bag jacket 14 fastened, in particular by one or more seams, which will be discussed in detail later. The flap 20 is also at one end of a traction device 22 coupled. The opposite end of the traction device 22 is connected to an electrically actuable activation unit 24 in the housing 12 coupled.
[0028] The activation unit 24 can be actuated selectively depending on the physique of the vehicle occupant to be protected. This is the activation unit 24 connected to a control device (not shown), which in turn receives and evaluates data from an occupant qualification device (not shown). The occupant qualification device supplies data about the occupant, which allows a classification into the classes “small vehicle occupant” and “normal sized vehicle occupant” or “large vehicle occupant” explained at the outset. The manner in which the data is obtained is irrelevant to the operation of the vehicle occupant restraint.
[0029] The traction device 22 can be, for example, a ribbon or a cord. in the in figure 1 embodiment shown has the traction means 22 between its two connection points a length that is dimensioned so that the traction device 22 with the knee airbag fully unfolded and inflated 10 is excited. The length of the traction device 22is dimensioned in such a way that it is shorter than when the knee airbag is fully deployed 10 adjusting distance of its two connection points. For this purpose, the traction device is shortened by the length ΔL.
[0030] In the figure 5 and figure 6 is the flap 20 for covering the one or more outflow openings 18 shown in different perspectives. The flap 20 is with a seam running substantially along its perimeter 26 on the gas bag jacket 14 fastened as gas-tight as possible. the seam 26 divides the flap 20 into one of the outflow openings 18 covering inner section 28 and a one-sided loose outer section 30 outside the seam 26 . the seam 26 is at least partially designed as a tear seam that tears open under a certain load.
[0031] The traction device 22 is at a certain point of the outer section 30 with the flap 20 tied together. How in particular from the side view of figure 5 can be seen, the connection point is chosen so that the traction means 22 with the inner section 28 the flap 20 forms an acute angle α, approximately in the range of 0° to 60°. Of course the inner section is 28 neither during inflation nor in the final unfolded state of the knee airbag 10 completely plan. However, this is not critical, i. H. the acute angle α can be on the inner section 28 corresponding averaged or interpolated plane can be obtained.
[0032] The different modes of operation of the vehicle occupant restraint device with such a knee airbag are described in more detail below.
[0033] figure 3 shows a situation in which the occupant qualification device has determined a small vehicle occupant. In this case, the control device actuates the activation unit 24 not, so the traction means 22 is not released. Due to the shortened length of the traction device 22 this exerts a tensile force F on the flap at the end of the unfolding process 20 at the junction in the outer section 30 out. This by unfolding the upper section of the knee airbag 10 certain force is so great that the seam 26 tears open The introduction of force via the traction mechanism 22 is optimal thanks to the acute angle α in that the flap 20 through the traction device 22 from the gas bag jacket 14 is effectively peeled off.
[0034] Due to the (partial) detachment of the flap 20 from the gas bag jacket 14 the upper section of the knee airbag can move 10 fully unfold, with the traction means 22 the flap 20 from the outflow openings 18 keeps away. The outflow openings 18 are thus released, and gas can escape from the knee airbag 10 escape. The internal pressure of the knee airbag 10 is thereby reduced, so that the impact of the knees of the small vehicle occupant on the fully inflated knee airbag 10 is dampened.
[0035] figure 4 shows the same situation as figure 3, but in the event that the occupant qualification facility has determined a normal sized or large vehicle occupant. In this case, the control device actuates the activation unit 24 and gives the means of traction 22 thereby free before the knee airbag 10 has fully developed. This means that the traction means 22 no pulling force on the flap 20 can exercise. The flap 20 stays with the gas bag coat 14 connected and are the outflow openings 18 not free. As a result, the gas bag internal pressure is kept largely constant in order to ensure a protective effect that is sufficient for the vehicle occupant of normal or large size.
[0036] As already mentioned, the design of the vehicle occupant restraint system is based on the usual specifications for crash tests with 5 percent and 50 percent or 95 percent dummies in a normal sitting posture and position (no so-called OOP positions). Reference List 10 knee gas bag 12 housing 14 gas bag coat 16 connection points 18 outflow openings 20 flap 22 traction means 24 activation unit 26 suture 28 inner section 30 outer section 32 instrument panel QUOTES INCLUDED IN DESCRIPTION
[0037] This list of documents cited 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
[0038] DE 102008028921 A1
[0003] DE 102009005771 A1
[0003]
Claims
[1] Vehicle occupant restraint device, with one between an instrument panel ( 32 ) and the knee airbag that can be deployed to the legs of a vehicle occupant ( 10 ), which has a gasbag coat ( 14 ) and at least one outflow opening formed therein ( 18 ) shows, a facility for the qualification of the vehicle occupant's physique, an activation unit ( 24 ) for selective release of the outflow opening ( 18 ), and a control unit which, depending on the qualification of the vehicle occupant's body type, activates the activation unit ( 24 ) activated. [2] Vehicle occupant restraint device according to claim 1, characterized in that the outflow opening ( 18 ) inside through a flap ( 20 ) is covered, which is detachable from the gasbag jacket ( 14 ) is attached, in particular by a tear seam. [3] Vehicle occupant restraint device according to claim 2, characterized in that the flap ( 20 ) to a traction element ( 22 ) is coupled, which in turn is connected to the activation unit ( 24 ) is coupled. [4] Vehicle occupant restraint device according to claim 3, characterized in that the length of the traction element ( 22 ) is dimensioned so that the traction element ( 22 ) at the end of the deployment of the knee gaiter ( 10 ) is tensioned and thereby the flap ( 20 ) from the gasbag coat ( 14 ) at least partially replaces. [5] Vehicle occupant restraint device according to claim 3 or 4, characterized in that a seam ( 26 ), in particular a tear seam, the flap ( 20 ) into one of the outflow openings ( 18 ) covering inner section ( 28 ) and an outer section ( 30 ) subdivided, and that the traction element ( 22) with the outer section ( 30 ) is connected. [6] Vehicle occupant restraint device according to claim 5, characterized in that the traction element ( 22 ) so in the knee sack ( 10 ) is arranged so that at the end of the unfolding process it is connected to the inner section ( 28 ) the flap ( 20 ) forms an acute angle α, preferably in the range of 30° to 60°. [7] Vehicle occupant restraint device according to one of the preceding claims, characterized in that the outflow opening ( 18 ) in the upper half, preferably in the upper third of the knee sac ( 10 ) is located. [8] Methods for protecting a vehicle occupant, comprising the following steps: – Qualifying the body type of the vehicle occupant; – Inflating one between an instrument panel ( 32 ) and the knee airbag that can be deployed for the legs of a vehicle occupant ( 10), which has a gasbag coat ( 14 ) and at least one outflow opening formed therein ( 18 ) exhibits, with gas; and – Adjusting the gas flow behavior by using an activation unit ( 24 ) to release the outflow opening ( 18 ) is activated depending on the qualification of the vehicle occupant's physique. [9] Method according to claim 8, characterized in that the qualification of the body type of the vehicle occupant involves a classification into one of the classes “small vehicle occupant” and “normal-sized vehicle occupant” and / or “large vehicle occupant”. [10] Method according to claim 8 or 9, characterized in that a traction element ( 22 ), which on the one hand is connected to the activation unit ( 24 ) and on the other hand to an outlet opening ( 18 ) covering flap ( 20 ) is coupled, at the end of the unfolding of the knee gas sack ( 10) is tensioned and thereby the flap ( 20 ) from the outflow opening ( 18 ) at least partially replaces.