RESTRAINING DEVICE AND AIRBAG MODULE

Abstract

The invention describes a holding device (12) for holding and releasing a tensioning means (14) of a vehicle safety system, e.g., an airbag tether. The holding device (12) includes a pyrotechnical actuator assembly (24) for holding and, in terms of signals, specifically releasing the tensioning means (14), wherein the actuator assembly (24) comprises a plastic base (26) in which a pyrotechnical unit (28) including a propelling charge and an igniter (30) is accommodated, wherein the pyrotechnical unit (28) has a rear side (36) and a front side (38). The holding device (12) has a tensioning means holder (40) which is directly adjacent at least to the front side (38) of the pyrotechnical unit (28), covers the same and is detachably supported on the plastic base (26) so that the tensioning means holder (40) detaches as a unit completely from the plastic base (26). The plastic material forming the plastic base (26) is injection-molded around the tensioning means holder (40) in the area of its longitudinal end associated with the pyrotechnical unit (28), and an area which is not injection-molded constitutes a holding portion (48) for the tensioning means (14). In addition, an airbag module (10) comprising a holding device (12) is described.

Claims

1-13. (canceled)

14. A holding device for holding and releasing a tensioning means of a vehicle safety system, specifically a tether of an airbag of a vehicle safety system, comprising a pyrotechnical actuator assembly for holding and, in terms of signals, specifically releasing the tensioning means, wherein the actuator assembly comprises a plastic base in which a pyrotechnical unit including a propellant charge and an igniter is accommodated and held, wherein the pyrotechnical unit has a rear side and an opposite front side, and comprising a tensioning means holder which is directly adjacent at least partially to the front side of the pyrotechnical unit and covers the same and which is detachably supported on the plastic base in such a way that the tensioning means holder detaches as a unit completely from the plastic base by triggering the igniter, wherein the plastic material forming the plastic base is injection-molded around tensioning means holder in the area of its longitudinal end associated with the pyrotechnical unit and an area that is not injection-molded is a holding portion for the tensioning means.

15. The holding device according to claim 14, wherein the plastic material forming the plastic base is also injection-molded around the pyrotechnical unit.

16. The holding device according to claim 14, wherein the tensioning means holder is made of a metal or a plastic material and is partially injection-molded around its outside.

17. The holding device according to claim 14, wherein the tensioning means holder includes one of a radially outward projection and a radially inwardly protruding recess when viewed in the longitudinal direction of the holding device at its portion accommodated in the plastic base.

18. The holding device according to claim 17, wherein the one of an outward projection and a radially protruding recess is peripheral.

19. The holding device according to claim 14, wherein the tensioning means holder includes a fastening portion accommodated in the plastic base as well as the holding portion adjacent thereto, wherein a contact face for the tensioning means is provided on the holding portion

20. The holding device according to claim 19, wherein the holding portion and the fastening portion together form a cylindrical surface on the outside.

21. The holding device according to claim 20, wherein a laterally projecting collar which is widened compared to the holding portion is connected to one end of the holding portion facing away from the fastening portion.

22. The holding device according to claim 14, wherein the pyrotechnical unit excluding its electric wires is completely contacted by the plastic base and the tensioning means holder.

23. The holding device according to claim 14, wherein the tensioning means holder includes a recess complementary to the pyrotechnical unit on its end face facing the pyrotechnical unit, in which recess a portion of an ignition head of the pyrotechnical unit is received.

24. The holding device according to claim 14, wherein the tensioning means holder includes a relief opening.

25. The holding device according to claim 24, wherein the relief opening preferably extends from the end face of the tensioning means holder facing the pyrotechnical unit to the end face of the tensioning means holder remote from the pyrotechnical unit.

26. The holding device according to claim 14, wherein the tensioning means holder is partially injection-molded in the plastic base and the plastic base is configured so that the plastic base remains free of cracks when the pyrotechnical unit is activated.

27. An airbag module for a vehicle safety system, comprising an airbag and a holding device according to claim 14, and comprising a tensioning means which is fastened to an airbag and is held on the holding device.

28. The airbag module according to claim 25, wherein a loop is formed at one end portion of the tensioning means which is not fastened to the airbag, wherein the loop is laid around the tensioning means holder in the non-triggered state of the holding device.

29. The airbag module according to claim 25, wherein a loop is formed at one end portion of the tensioning means which is not fastened to the airbag, wherein the loop is laid around the holding portion of the tensioning means holder in the non-triggered state of the holding device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Further advantages and features of the invention will be evident from the following description and from the drawings which are referred to, and wherein:

[0030] FIG. 1 shows an airbag module according to the invention comprising a holding device according to the invention in a non-triggered state,

[0031] FIG. 2 shows the airbag module of FIG. 1, with the holding device being triggered,

[0032] FIG. 3 shows the holding device of the airbag module illustrated in FIGS. 1 and 2,

[0033] FIG. 4 shows another embodiment of a holding device according to the invention,

[0034] FIG. 5 shows a third embodiment of a holding device according to the invention,

[0035] FIG. 6 shows another airbag module according to the invention comprising a holding device according to the invention,

[0036] FIG. 7 shows the airbag module of FIG. 5, with the holding device being reinforced,

[0037] FIG. 8 shows the airbag module of FIGS. 5 and 6, with the holding device being in a triggered state,

[0038] FIG. 9 shows another airbag module according to the invention comprising a holding device according to the invention,

[0039] FIG. 10 shows the airbag module of FIG. 8, with the holding device being reinforced, and

[0040] FIG. 11 shows the airbag module of FIGS. 8 and 9, with the holding device being in a triggered state.

DESCRIPTION

[0041] FIG. 1 illustrates an airbag module 10 comprising a holding device 12 for holding and releasing a tensioning means 14 of a vehicle safety system, specifically a tether.

[0042] In addition to the holding device 12, the airbag module 10 comprises an airbag case 16 and an airbag 18, the airbag 18 being accommodated folded in the airbag case 16 in the non-triggered state of the airbag module 10.

[0043] The tensioning means 14 is fastened to the airbag 18 and is held on the holding device 12 when the holding device 12 is in a non-triggered state, as illustrated in FIG. 1. In this way, the tensioning means 14 can restrict unfolding of the airbag 18.

[0044] FIG. 2 illustrates the airbag module 10 in a state in which the holding device 12 is triggered and, thus, the tensioning means 14 is released. In this case, the airbag 18 can freely deploy.

[0045] FIG. 3 illustrates the holding device 12 of FIGS. 1 and 2 in a detail view in the non-triggered state.

[0046] The holding device 12 comprises a pyrotechnical actuator assembly 24 for holding and, in terms of signals, specifically releasing the tensioning means 14.

[0047] The actuator assembly 24 comprises a plastic base 26 and a pyrotechnical unit 28 including an igniter 30. The igniter 30 has electric wires 32 and an ignition head 34. In the ignition head 34, a propelling charge is contained so that a propellant is generated by triggering the igniter 30.

[0048] The pyrotechnical unit 28 is received and held in the plastic base 26. In particular, the plastic material forming the plastic base 26 is injection-molded at least partially around the pyrotechnical unit 28.

[0049] The pyrotechnical unit 28 has a rear side 36 and an opposite front side 38. The igniter may be electrically contacted on its rear side 36.

[0050] Further, the actuator assembly 24 includes a tensioning means holder 40 which is directly adjacent at least to the front side 38 of the pyrotechnical unit 28 and covers the same. More precisely, the tensioning means holder 40 is adjacent to the ignition head 34, i.e., in an area where the plastic material forming the plastic base 26 is not injection-molded around the ignition head 34.

[0051] The tensioning means holder 40 specifically constitutes a cap.

[0052] In the shown embodiment, the tensioning means holder 40 includes, on its end face 42 facing the pyrotechnical unit 28, a recess 44 complementary to the pyrotechnical unit 28 in which a portion of the ignition head 34 of the pyrotechnical unit 28 is received.

[0053] Thus, the pyrotechnical unit 28 excluding its electric wires 32 is contacted and, resp., enclosed completely by the plastic base 26 and the tensioning means holder 40.

[0054] In a further embodiment (not shown), the tensioning means holder 40 does not include any recess on its end face 42 facing the pyrotechnical unit 28. In such embodiment, the end face 42 facing the pyrotechnical unit 28 can form a continuous and specifically planar surface. The front side 38 of the pyrotechnical unit 28 can be adjacent at least partially to the end face 42 of the tensioning means holder 40. In this embodiment, too, the pyrotechnical unit 28 excluding its electric wires 32 is completely enclosed by the plastic base 26 and the tensioning means holder 40.

[0055] Further, the tensioning means holder 40 can be made of plastic material or of metal. The tensioning means holder 40 illustrated in FIGS. 1 to 3 is specifically a tensioning means holder 40 made of plastic material.

[0056] In order to enable the tensioning means 14 to be released, the tensioning means holder 40 is detachably supported on the plastic base 26 in such a way that, by triggering the igniter 30, it detaches as a unit completely from the plastic base 26.

[0057] More precisely, the tensioning means holder 40 is supported on the plastic base 26 by the plastic material forming the plastic base 26 being injection-molded around the tensioning means holder 40, specifically being injection-molded partially on the outside, in the area of its longitudinal end associated with the pyrotechnical unit 28.

[0058] By the injection-molding, the tensioning means holder 40 is held frictionally and/or non-positively in the plastic base 26.

[0059] In particular, the tensioning means holder 40 is partially injection-molded in the plastic base 26 and the plastic base 26 is configured so that the plastic base 26 remains free of cracks when the pyrotechnical means 28 is activated.

[0060] The portion of the tensioning means holder 40 which is accommodated in the plastic base 26 forms a fastening portion 46.

[0061] An area of the tensioning means holder 40 which is not surrounded by injection-molding is a holding portion 48 for the tensioning means 14. A contact face 49 for the tensioning means 14 is provided on the holding portion 48.

[0062] The holding portion 48 is directly connected to the fastening portion 46.

[0063] The holding portion 48 and the fastening portion 46 together form a cylindrical surface 50 on the outside. Thus, when the holding device 12 is triggered, the tensioning means 14 can easily slip off the tensioning means holder 40.

[0064] In order to retain the tensioning means 14 on the holding device 12, a loop 52 is formed at one end portion 51 of the tensioning means 14 which is not fastened to the airbag 18 (see FIG. 1). As a matter of course, the tensioning means may comprise, instead of the loop 52, other elements which enable the tensioning means 14 to be retained on the holding device 12.

[0065] In the non-triggered state of the holding device 12, the loop 52 is laid around the tensioning means holder 40, as illustrated in FIG. 1, specifically around the holding portion 48 of the tensioning means holder 40.

[0066] In order to prevent the tensioning means 14 from slipping off the holding portion 48 when the holding device 12 is not triggered, a laterally projecting collar 54 which is widened compared the holding portion 48 is connected to an end of the holding portion 48 facing away from the fastening portion 46.

[0067] For increasing a retaining force acting on the tensioning means holder 40, the tensioning means holder 40 can include a radially outward projection 56 when viewed in the longitudinal direction of the holding device 12 at its portion accommodated in the plastic base 26, i.e., in the fastening portion 46. In this way, the tensioning means holder 40 is held not only frictionally but also positively in the plastic base 26.

[0068] The projection 56 is configured to be peripheral in the shown embodiment.

[0069] As an alternative, the tensioning means holder 40 may include an inwardly protruding recess 57 as shown in the embodiment of FIG. 3, for example. The recess 57 can equally be peripheral.

[0070] As a matter of course, those skilled in the art are completely free in designing the projection 56 or else several projections 56 and/or one or more radially inwardly protruding recesses and/or the combination of one or more projections 56 with one or more recesses, as the plastic material forming the plastic base 26 is injection-molded around the tensioning means holder 40.

[0071] FIG. 4 illustrates a holding device 12 according to another embodiment.

[0072] Said holding device 12 differs from the holding device illustrated in FIGS. 1 to 3 by the shape of the tensioning means holder 40.

[0073] In particular, the tensioning means holder 40 illustrated in FIG. 4 is made of metal. The tensioning means holder 40 is a pressure die casting, for example.

[0074] The holding device 12 according to FIG. 4 can also be used in the airbag module 10 shown in FIGS. 1 and 2.

[0075] FIG. 5 illustrates a holding device 12 according to a third embodiment.

[0076] Said holding device differs from the holding device illustrated in FIGS. 1 to 3 by the shape of the tensioning means holder 40.

[0077] In order to increase a retaining force acting on the tensioning means holder 40, the tensioning means holder 40 includes a radially inwardly protruding recess 57 at its portion accommodated in the plastic base 26, i.e., in the fastening portion 46. The recess 57 is configured to be peripheral in the illustrated embodiment.

[0078] Furthermore, the tensioning means holder 40 illustrated in FIG. 5 has a relief opening 61. The relief opening 61 extends from the end face 42 facing the pyrotechnical unit 28 and, thus, in the embodiment according to FIG. 5 from the recess 44 of the tensioning means holder 40 complementary to the pyrotechnical unit 28 toward the end face 60 of the tensioning means holder 40 remote from the pyrotechnical unit 28.

[0079] The relief opening 61 in the shown embodiment has a bore with parallel lateral edges in the beginning of the relief opening 61.1 and a bore with conical side edges in the end of the relief opening 61.2. Of course, the relief opening 61 may also have other geometries, in particular a bore with continuously parallel or continuously conical side edges. Preferably, the relief opening 61 can be introduced into the tensioning means holder 40 already during manufacture thereof. Also, it is conceivable to introduce the relief opening 61 later into the tensioning means holder 40.

[0080] Here, the maximum size and/or the maximum diameter D of the relief opening 61 is adjusted to an ignition force/energy of the pyrotechnical means 28 in the beginning of the relief opening 61.1 which is disposed in the area directly adjacent to the end face 42 facing the pyrotechnical unit 28.

[0081] The relief opening 61 can help reduce specifically excess energy of the pyrotechnical unit 28 during triggering, for example if there is provided too high ignition force/energy of the pyrotechnical unit 28. Thus, it can be ensured, for example, that the tensioning means holder 40 can be caught in an airbag module 10 and, resp., an airbag module case in a controllable manner, even if the ignition force/energy of the pyrotechnical unit 28 is actually too high for the holding device 12.

[0082] The holding device 12 according to FIG. 5 can also be used in the airbag modules 10 shown in FIGS. 1 and 2 or in FIGS. 6 to 11. In the embodiments of the FIGS. 6 to 11, the relief opening 61, specifically the end of the relief opening 61.2, can constitute the recess 62 for receiving the reinforcing element 58.

[0083] Hereinafter, with reference to the FIGS. 1 and 2, triggering of the airbag module 10 and of the holding device 12 will be described.

[0084] When the airbag module 10 is triggered, the airbag 18 is inflated.

[0085] As long as the holding device 12 is not triggered, the airbag 18 can deploy only to a limited extent, however, as the tensioning means 14 prevents the airbag 18 from completely deploying. As a matter of course, the tensioning means 14 may also be connected, in other embodiments (not shown), to a valve that allows discharge of gas from the airbag 18 after release of the tensioning means 14, for example.

[0086] It depends on a sitting position of a vehicle occupant whether the holding device 12 is triggered and, consequently, the tensioning means 14 is released.

[0087] If a vehicle occupant is sitting further distant from an instrument panel or if the vehicle occupant is in a reclined position, a higher airbag volume is required than in a sitting position close to the instrument panel.

[0088] If a larger airbag volume is required, the tensioning means 14 is released. This is performed by igniting the pyrotechnical unit 28 as illustrated in FIG. 2.

[0089] By the ignition, a propelling gas is generated by means of the propellant contained in the ignition head 34, thereby force being applied to the tensioning means holder 40 and the latter being detached from the plastic base 26.

[0090] In particular, the tensioning means holder 40 is completely detached from the plastic base 26 so that no remainder of the tensioning means holder 40 is left on the plastic base 26. The plastic base 26 remains free of cracks.

[0091] Hence, the tensioning means 14 may slip off the tensioning means holder 40 and is no longer retained by the holding device 12.

[0092] The airbag 18 can thus deploy unhindered.

[0093] The FIGS. 6 to 8 illustrate an airbag module 10 according to a further embodiment.

[0094] The airbag module 10 according to FIGS. 6 to 8 differs from the airbag module 10 according to FIGS. 1 and 2 in that the holding device 12 can be reinforced.

[0095] The holding device 12 particularly comprises a reinforcing element 58 which serves to increase the stability of the tensioning means holder 40.

[0096] For this purpose, the reinforcing element 58 is supported to be axially movable between a first position shown in FIG. 7 and a second position shown in FIG. 8. More precisely, the reinforcing element 58 is movable along a longitudinal axis of the holding device 12.

[0097] In the second position, the reinforcing element 58 is disengaged from the tensioning means holder 40 and, in a first position, the reinforcing element 58 is at least partially received, as shown in FIG. 7, in the tensioning means holder 40 and reinforces the latter mechanically. In the reinforced state, the holding device 12 can absorb transverse forces of more than 2.5 kN, specifically more than 5 kN, for example.

[0098] For receiving the reinforcing element 58, the tensioning means holder 40 includes a recess 62 at an end face 60 facing away from the plastic base 26 in which the reinforcing element 58 is at least partially received positively and/or frictionally in its first position.

[0099] When being loaded, the tensioning means holder 40 can consequently bear against the reinforcing element 58.

[0100] For example, the reinforcing element 58 is suitable for reinforcing the holding devices 12 shown in the FIGS. 1 to 3 and 5.

[0101] According to the embodiment illustrated in FIGS. 6 to 8, the holding device 12 has a fixed bearing 64 which is arranged spaced apart from the tensioning means holder 40.

[0102] The reinforcing element 58 is received to be axially movable in the fixed bearing 64. In particular, the reinforcing element 58 is held frictionally in the bearing 64 so that the reinforcing element 58 cannot slip inadvertently within the bearing 64.

[0103] For this purpose, the bearing 64 has a bore 65 in which the reinforcing element 58 is inserted.

[0104] The reinforcing element 58 can be displaced preferably manually within the bearing 64.

[0105] In order to limit displacement of the reinforcing element 58, the reinforcing element 58 includes a stop 66 disposed spaced apart from the ends of the reinforcing element.

[0106] The stop 66 is a peripheral collar, for example. Alternatively, the stop 66 may include one or more lateral projections.

[0107] In its second position, the reinforcing element 58 abuts against the bearing 64 with the stop 66.

[0108] The reinforcing element 58 is, for example, an oblong ram specifically made of plastic material or metal.

[0109] When the holding device 12 is triggered, the bearing 64 serves as a catching device for the tensioning means holder 40 as illustrated in FIG. 8.

[0110] For this purpose, the bearing 64 has a recess 70 for receiving the tensioning means holder 40 at an end face 68 facing the tensioning means holder 40. Hence, the tensioning means holder 40 is held on the holding device 12 even after the holding device 12 is triggered.

[0111] The FIGS. 9 to 11 illustrate an airbag module 10 according to a further embodiment.

[0112] FIG. 9 illustrates the airbag module 10 comprising a holding device 12, wherein the holding device 12 is not reinforced. In FIG. 10, the holding device 12 is shown in a reinforced state. FIG. 11 illustrates the holding device 12 in a triggered state.

[0113] The airbag module 10 shown in FIGS. 9 to 11 differs from the airbag module 10 shown in FIGS. 6 to 8 by the shape of the reinforcing element 58 as well as by the bearing of the reinforcing element 58.

[0114] The reinforcing element 58 according to FIGS. 9 to 11 is tightly fixed specifically to a linearly movable bearing part 72. Thus, the bearing part 72 moves along with the reinforcing element 58 from the first to the second position.

[0115] In order to enable the bearing part 72 to be displaced, the displaceable bearing part 72 is frictionally guided in a linear guide. The bearing part 72 can be displaced preferably manually.

[0116] For example, the linear guide is formed in the airbag case 16. The linear guide may be designed as a dovetail guide, for example.

[0117] In addition, there is provided a stop element 74 that delimits displacement of the bearing part 72 in a direction away from the plastic base 26. The stop element 74 is also disposed on the airbag case 16.