Testing device for an airbag module

Abstract

A testing device for an airbag module includes a support structure to which an airbag module containing an airbag can be fastened, the support structure forming a passage which can be penetrated by the airbag, at least one lid movably fastened to the support structure by fastening means between a closing position in which the lid closes the passage and an open position in which the passage is opened, and a closure device that closes the lid in the closing position by applying a closing force to the lid, wherein the lid comprises at least one first force sensor measuring the opening force applied to the lid by the airbag when moved out of the closed position by the airbag.

Claims

1. A testing device for an airbag module, comprising, a support structure, an airbag module, an airbag, the airbag module to be fastened to the support structure, said support structure including a passage for penetration by the airbag; a lid movably fastened to the support structure by a fastener between a closing position in which the lid closes the passage and an open position in which the passage is opened, and a closure device that closes the lid in the closing position by applying a closing force to the lid, said lid comprising at least one first force sensor measuring an opening force applied to the lid by the airbag when the lid is moved out of the closed position, wherein the lid is fastened to the support structure by at least one flexible belt, said belt co-operating with at least a second force sensor measuring the hinge force applied to the belt when the lid is moved out of the closed.

2. The testing device according to claim 1, wherein the lid comprises an acceleration sensor measuring the acceleration of the lid when the lid is moved out of the closed position by the airbag.

3. The testing device according to claim 1, wherein the belt, at least partially, encloses the lid.

4. The testing device according to claim 1, further comprising a first lid fastened to the support structure by a first lid fastener and a second lid fastened to the support structure by a second lid fastener.

5. The testing device according to claim 4, further including an adjustment device for adjusting, the closing force.

6. The testing device according to claim 5, wherein the adjustment device for adjusting the closing force comprising at least one magnet acting between the support structure and the closure device.

7. The testing device according to claim 1, wherein the lid is at least partially made of carbon fiber reinforced plastic.

8. The testing device according to claim 1, wherein the testing device comprises a high-speed camera.

9. The testing device according to claim 1, wherein the lid is at least partially made of a transparent material.

10. The testing device according to claim 1, further comprising a catchment device for receiving the lid in the open position.

11. The testing device according to claim 1, wherein the support structure further comprises a number of standardized mounting points for fastening the airbag module to the support structure.

Description

BRIEF DESCRIPTION OF THE DRAWING

(1) Other features and advantages of the present invention will be more readily apparent upon reading the following description of currently preferred exemplified embodiments of the invention with reference to the accompanying drawing, in which:

(2) The present disclosure is described in detail with reference to the drawings attached wherein

(3) FIG. 1A is a principle perspective sketch of a first embodiment of a testing device according to the present application,

(4) FIG. 1B is a principle partial sectional and not scaled view through the testing device shown in FIG. 1A,

(5) FIG. 1C is a separate not scaled bottom view of the lid of the testing device shown in FIGS. 1A and 1B,

(6) FIG. 2 is a principle perspective sketch of a first embodiment of a testing device according to the present application,

(7) FIG. 3A is a principle and streamlined top view on the testing device according to the first embodiment, and

(8) FIG. 3B is a principle and streamlined top view on the testing device according to the second embodiment.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(9) The following description relates to FIGS. 1A and 1B which both show an embodiment of a testing device 10.sub.1 for testing an airbag module 12 hosting a folded airbag 14 (see FIG. 1B). The testing device 10.sub.1 comprises a support structure 16 which is composed of a bearing plate 18, a number of pillars 20 fastened to the bearing plate 18 and a work plate 22 that rests on the pillars 20. The work plate 22 forms a passage 24 which has a substantially rectangular cross section. Furthermore the testing device 10.sub.1 comprises one lid 26 that is movably fastened to the work plate 22 by fastening means 27 embodied as a number of flexible belts 28. As evident from FIG. 1B the belts 28 enclose the lid 26. The lid 26 can be moved between a closing position (see FIG. 1B) in which the lid 26 closes the passage 24 and an open position in which the lid 26 clears the passage 24 (FIG. 1A). The belts 28 define the movement of the lid 26 between the closing position and the open position. The belts 28 provide a hinge-like fastening of the lid 26 to the support structure 16. The movement of the lid 26, which is approximately a rotational movement, is indicated by the arrow P1 in FIG. 1B.

(10) The testing device 10.sub.1 further comprises a closure device 30 which applies a closing force FC to the lid 26 when the lid 26 is in the closing position. The closure device 30 comprises a first plate 32 and a second plate 34 that are movably connected to each other by a hinge joint 36. The first plate 32 is fixedly connected to the work plate 22 whereas the second plate 34 may be moved in a position in which it is partially overlapping the passage 24.

(11) The testing device 10.sub.1 is equipped with means 38 by which the closing force FC applied by the closure device 30 may be adjusted. In the embodiment shown in FIGS. 1A and 1B the means 38 comprise a magnet 40, in particular a permanent magnet 40 arranged in the second plate 34 of the closure device 30 that interacts with the work plate 22 that is made of metal, thereby creating the closing force FC that keeps the lid 26 in the closing position. The magnet 40 may be changed for adjusting the closing force FC. Alternatively the magnet 40 may be a permanent magnet such that the force acting between the lid 26 and the work plate 22 can be adjusted depending on the current applied.

(12) Beyond that the testing device 10.sub.1 is equipped with a catchment device 42 (FIG. 1A) which defines the open position of the lid 26 and comprises dampening elements 44 such as a cushion or an air buffer to avoid a hard impact of the lid 26 when reaching the open position. The testing device 10.sub.1 is provided with a high-speed camera 46 by which the movement of the lid 26 and the inflation of the airbag 14 may be followed.

(13) FIG. 1C separately shows the lid 26 by means of a bottom view such that the surface facing to the airbag module 12 in the closing position is visible. One can see that the lid 26 is provided with a number of first force sensors 48, in this case with a variable number of first force sensors 48. However, the number of first force sensors 48 can be varied according to the relevant requirement. Beyond that the lid 26 is provided with one acceleration sensor 61. Again, the number of acceleration sensors can be varied if beneficial.

(14) The lid 26 is made of carbon fiber reinforced plastic 50 which is symbolized by the crosshatching of area A of the lid 26 that is separately illustrated in a magnified way. It is possible to provide the lid 26 with transparent sections such that one may through the lid 26 and see the folded airbag 14 when the lid 26 is in the closing position.

(15) Referring to FIG. 1B the testing device 10.sub.1 comprises second force sensors 52 that interact with the belts 28. Moreover, the support structure 16 is equipped with a number of mounting points 54 by which the airbag module 12 may be fastened to the work plate 22. In this case the airbag module 12 is fastened to the work plate 22 by means of screws (not shown). The mounting points 54 are standardized such that the majority of airbag modules 12 available in the marked may be fastened to the work plate 22 without further adjustments.

(16) A computer 56 is connected to the first force sensors 48, the second force sensors 52 and the high-speed camera 46 by means of cables 58. A wireless connection may also be conceivable. The computer 56 may also be connected to the airbag module 12, the permanent magnet and other components of the testing device 10.sub.1 (not shown).

(17) The testing device 10.sub.1 is used as follows: In the initial state that is shown in FIG. 1B the lid 26 is in the closing position. The second plate 34 of the closure device 30 is flush with the first plate 32 and keeps the lid 26 in the closing position by means of the closing force FC generated by the magnet 40 arranged in the second plate 34 and interacting with the work plate 22.

(18) The airbag module 12 is now triggered, e.g. by a corresponding signal generated by the computer 56. A gas generator 60 of the airbag module 12 generates pressurized gas which is introduced into the airbag 14, thereby inflating the airbag 14. Upon inflation the airbag 14 expands along the direction indicated by the arrow P3 in FIG. 1B and abuts on the lid 26. The opening force FO the airbag 14 imposes on the lid 26 is measured by the first force sensors 48. As in this embodiment a variable number of force sensors are arranged on the lid 26 the force distribution over the lid 26 may be determined.

(19) In case the opening force FO the airbag 14 imposes on the lid 26 is sufficiently high the lid 26 moves into the open position, thereby moving the second plate 34 of the closure device 30 relative to the first plate 32 as indicated by the arrow P2 in FIG. 1B. In the open position the lid 26 is received by the catchment device 42 as approximately shown in FIG. 1A. For the sake of clarity the airbag 14 is not shown in FIG. 1A. The bulk of the airbag 14 penetrates the passage 24 such that the airbag 14 can be fully inflated above the work plate 22. The testing device 10.sub.1 reaches its final state once the airbag 14 is deflated after full inflation.

(20) The deflated airbag 14 and the triggered airbag module 12 can easily be removed and be replaced by an untriggered airbag module 12. The lid 26 and the second plate 34 may be moved back to the initial state as shown in FIG. 1B without significant effort.

(21) The movement of the airbag 14, of the lid 26 and of the second plate 34 during the inflation of the airbag 14 may be monitored by the high-speed camera 46. The forces acting on the belts 28 during the inflation may be measured by the second force sensors 52. These forces are referred to as hinge forces FH. The hinge forces FH are an important parameter to estimate whether the airbag cover will stick to the instrument panel or not when the airbag inflates. As mentioned, the opening forces FO the airbag 14 imposes on the lid 26 can be measured by the first force sensors 48. These data can be processed and analyzed by the computer 56 such that different airbag modules 12 may be representatively compared to each other within a short time using the same testing device 10.sub.1.

(22) FIG. 2 shows a perspective principle view of a second embodiment of the testing device 10.sub.2. The basic construction of the testing device 10.sub.2 according to the second embodiment is the same as of the testing device 10.sub.1 of the first embodiment. Thus, only the differences will be discussed in the following.

(23) The passage 24 of the support structure 16 is covered by a first lid 26.sub.1 and a second lid 26.sub.2. The first lid 26.sub.1 is fastened to the support structure 16 by two first fastening means 27.sub.1 whereas the second lid 26.sub.2 is fastened to the support structure 16 by two second fastening means 27.sub.2. The fastening means 27.sub.1, 27.sub.2 can be designed as described with reference to the first embodiment. The way the first lid 26.sub.1 moves when the airbag 14 is inflating is indicated by the arrow P4.

(24) It is worth mentioning that the first fastening means 27.sub.1 is equipped with a first group of second force sensors 52.sub.1 while the second fastening means 27.sub.2 comprises a second group of second force sensors 52.sub.2. In the second embodiment shown in FIG. 2 each group 52.sub.1, 52.sub.2 consists of two second force sensors 52. The number of second force sensors 52 can be varied if considered beneficial.

(25) The closure device 30 comprises a first sub-unit 31.sub.1 and a second sub-unit 31.sub.2. They are arranged such that they partially cover the first lid 26.sub.1 and the second lid 26.sub.2 when in the closing position. The way the second sub-unit 31.sub.2 is moving when the airbag 14 is inflating is indicated by the arrow P5.

(26) For the sake of clarity, the computer 56 and the cables 58 are not shown. However, the accelerations and forces acting on the first lid 26.sub.1 and the second lid 26.sub.2 can be detected and analyzed in the same way as described for the first embodiment. One difference is that the behavior of the first lid 26.sub.1 and the second lid 26.sub.2 can be detected independent of each other.

(27) FIG. 3A is a streamlined top view on the first embodiment of the testing device 10.sub.1. FIG. 3B is a streamlined top view on the second embodiment of the testing device 10.sub.2.

(28) A pivot axis R for the lid 26, a first pivot axis R1 for the first lid 26.sub.1 and a second pivot axis R2 for the second lid 26.sub.2 are indicated by a solid line. The dashed line indicates the contact areas by which the lid, the first lid 26.sub.1 and the second lid 26.sub.2 are contacting or at least almost contacting the work plate 22 when in the closing position. While the contact area of the first embodiment of the testing device 10.sub.1 is approximately U-shaped, the contact area of the second embodiment of the testing device 10.sub.2 is approximately H-shaped.

(29) When comparing FIGS. 3A and 3B it becomes apparent that the turning axis S around which the closure device 30 of the testing device 10.sub.1 of the first embodiment rotates when the airbag is inflating is perpendicular to the turning axes S1, S2 of the closure device 30 according to the second embodiment of the testing device 10.sub.2.