Tensioner drive for a seatbelt retractor

Abstract

Tensioner drive (1) for a belt retractor (3) with a feed tube (10) and a gas generator (20) attached to one end of the feed tube (10), which feeds gas (G) into the feed tube (10) after ignition, wherein the gas generator (20) - viewed in the direction of gas flow - a drive body (40) is arranged downstream, characterized in that - the cross-section of the feed tube (10) is larger than the cross-section of the drive body (40) and the drive body (40) has play inside the feed tube (10), - the drive body (40) has at least in sections an adjustment cross-section (JQ) that deviates from a circular cross-section and - an alignment device (100) is arranged between the gas generator (20) and the drive wheel (30), which interacts with the adjustment cross-section (JQ) of the drive body (40) and enforces a predetermined alignment and target position of the drive body (40) relative to the drive wheel (30).

Description

[0001] The invention relates to a tensioner drive for a seatbelt retractor, wherein the tensioner drive is equipped with a feed tube and a gas generator attached to one end of the feed tube, which feeds gas into the feed tube after ignition. Such a tensioner drive is known, for example, from US Patent 9,555,768 B2. In the previously known tensioner drive, the feed tube remains pressurized even after the tensioning process has been completed. A tensioner drive with the features according to the preamble of claim 1 is known from German Patent Application DE 10 2007 040 254 A1.

[0002] The invention is based on the objective of further developing a tensioner drive of the type described above.

[0003] This problem is solved according to the invention by a tensioner drive with the features according to claim 1. Advantageous embodiments of the belt retractor according to the invention are specified in the dependent claims.

[0004] A significant advantage of the tensioner drive according to the invention is that, despite the play of the drive body, the drive body assumes a predetermined target position when engaging the drive wheel; this target position is enforced by the alignment device provided according to the invention.

[0005] In a preferred embodiment of the tensioner drive, the adjustment cross-section has at least two adjustment sections, each interacting with a corresponding, inversely shaped alignment section of the alignment device. The at least two adjustment sections of the drive body are preferably either concave or convex.

[0006] To ensure a leakage of the drive system with respect to the drive body, it is considered advantageous if the alignment sections are radially larger than the adjustment sections and an axial channel remains between the adjustment sections and the associated alignment sections, which would allow an axial gas flow past the drive body.

[0007] It is advantageous if the outer contour of the drive body is shaped in a continuously differentiable way in the adjustment cross-section.

[0008] In particular, it is advantageous if the drive body has four radially outwardly curved, bump-shaped adjustment sections, each of which engages in an associated alignment section of the alignment device, the bump-shaped adjustment sections of the drive body are arranged rotationally symmetrically around the central axis of the drive body, the alignment sections of the alignment device are arranged concavely and rotationally symmetrically around the central axis of the feed tube, and the alignment device causes the drive body to be aligned in such a way that, in the area between the alignment device and the drive wheel, the central axis of the drive body is concentric to that of the feed tube and / or lies in a predetermined target input plane of the drive wheel.

[0009] Regarding the axial design of the drive body, it is advantageous if the drive body has a first drive section, which is arranged at an end of the drive body facing the drive wheel and engages the drive wheel as the first section of the drive body after the gas generator is triggered, and a second drive section directly or indirectly connected thereto, the cross-section of the first drive section differing from that of the second drive section and preferably being round, and the second drive section of the drive body having the adjustment cross-section mentioned above. The first drive section can advantageously be optimized for the initial contact between the drive wheel and the drive body.

[0010] To ensure alignment of the drive unit during the assembly of the tensioner drive, it is considered advantageous if it is already partially positioned in the alignment device in the starting position before the gas generator is triggered.

[0011] It is also advantageous if the adjustment cross-section varies in the axial direction and is provided with pockets in certain sections, each pocket being arranged between two tangentially adjacent convex, particularly bump-shaped, adjustment sections. Pockets in such an arrangement simplify the manufacture of the drive body, for example, in the case of an injection molding process.

[0012] The alignment device is preferably formed by a deformed section of the feed tube, preferably deformed by a press-fitting process, or preferably includes at least such a deformed section.

[0013] Alternatively or additionally, it can be advantageously provided that the feed pipe has a closed pipe section, to one end of which the gas generator is connected and to the other end of which a one-piece molded trough section is attached, into which the drive wheel engages from the outside, and the alignment device comprises an alignment element that is mounted in the trough section - viewed in the direction of drive - in front of the drive wheel.

[0014] The alignment element is preferably an alignment ramp that is placed on the inside of the channel section.

[0015] It is advantageous if the alignment device also forms a stop area.

[0016] In the latter embodiment, it is advantageous if, viewed in the direction of gas flow, the gas generator is followed by the drive body and a thrust element that pushes the drive body after ignition of the gas generator, a sealing element is arranged in front of the thrust element in the direction of gas flow, the alignment device forms a stop area dimensioned such that the drive body can pass through the stop area but the thrust element is stopped, and the sealing element reaches the stop area in front of the thrust element, seals the supply pipe against gas flow before reaching the stop area, and becomes non-sealing upon entering the alignment device, allowing the gas from the gas generator to pass through.

[0017] The invention also relates to a belt retractor with a tensioner drive. According to the invention, the tensioner drive is designed as described above, and the drive wheel of the tensioner drive is connected directly or indirectly to a belt spool of the belt retractor and – driven by a movement of the drive body past the drive wheel – can be set into a rotational movement along a direction of rotation corresponding to the winding direction of the belt retractor.

[0018] The invention is explained in more detail below with reference to exemplary embodiments; the following are shown as examples: Fig. 1-4 Components of a first embodiment of a tensioner drive according to the invention and Fig. 5 a variant design of a drive unit with pockets.

[0019] For the sake of clarity, the same reference symbols are always used in the figures for identical or comparable components.

[0020] The Fig. 1 and Fig. Figure 2 shows components of a first embodiment of a tensioner drive 1 according to the invention, with which a belt spool 2 of a belt winder 3 comprising the tensioner drive 1 can be driven in the belt winding direction. In the illustration according to Fig. Figure 1 shows the state of the tensioner drive 1 before the start of the tensioning process, such that the drive body 40 has not yet reached the drive wheel 30; in the illustration according to Fig. Figure 2 shows the state of the tightening drive 1 after the end of the tightening process.

[0021] The tensioner drive 1 comprises a feed tube 10, a gas generator 20 attached to one end 11 of the feed tube 10, a drive wheel 30 and a drive body 40 located at least partially in the feed tube 10 before the gas generator 20 is ignited, which drives the drive wheel 30 after the gas generator 20 has been ignited.

[0022] In the embodiment according to the Fig. 1 and Fig. 2 The drive body 40 is a single piece and is formed by a deformable drive rod, as in the Fig. Figure 3 shows in more detail as an example. The cross-section of the drive body 40 is (at least with regard to the part located in the feed tube 10) smaller than the cross-section of the feed tube 10, so that the drive body 40 is free of sealing effect from the outset and the drive body 40 has play within the feed tube 10.

[0023] Furthermore, the Fig. 3, that the drive body 40 has a first (or front) drive section 41, which is arranged at an end of the drive body 40 facing the drive wheel 30 and engages in the drive wheel 30 as the first section of the drive body 40 after the gas generator 20 is triggered; this front drive section 41 has, for example, a circular cross-section.

[0024] Directly or indirectly, a second drive section 42 is connected, which has an adjustment cross-section JQ that deviates from a circular cross-section. The adjustment cross-section JQ is preferably present at least in that axial section of the drive body 40 which, before the tightening process, lies in an alignment device 100 arranged between the gas generator 20 and the drive wheel 30, or which passes through the alignment device 100 during the tightening process.

[0025] The Fig. Figure 4 shows the cross-section of the drive body 40 and that of the feed tube 10 along the section line IV-IV according to Fig. 1, i.e., in the area of ​​the alignment device 100. It can be seen that the adjustment cross-section JQ is shaped in such a way that it interacts with the alignment device 100: Specifically, the alignment device 100 with the adjustment cross-section JQ enforces a predetermined orientation and target position of the drive body 40 relative to the drive wheel 30. The drive body 40 lies, as the Fig. Figure 1 shows the starting position before the gas generator 20 is triggered, already with the adjustment cross-section JQ in the alignment device 100, in order to ensure the desired alignment at the start of the tightening process.

[0026] In the embodiment according to Fig. In sections 3 and 4, the alignment device 100 is manufactured by forming, preferably by a press-fitting process, the feed tube 10; specifically, the forming process creates four pressed-in sections EA, which extend radially inwards towards the drive body 40. The pressed-in sections EA of the alignment device 100 are arranged rotationally symmetrically about the central axis of the feed tube 10. Between each pair of pressed-in sections EA is an alignment section AA, which retains the original diameter of the feed tube 100 and is thus expanded and concave relative to the adjacent pressed-in sections EA, and is each suitable for receiving a radially outwardly curved or convex, bump-shaped adjustment section JS of the adjustment cross-section JQ.

[0027] In the embodiment according to Fig. In sections 3 and 4, the drive body 40, or rather its approximately square adjustment cross-section JQ, has four radially outwardly curved, bump-shaped adjustment sections JS, each forming a corner of the approximately square adjustment cross-section JQ and each engaging in an associated concave alignment section AA of the alignment device 100. In other words, the adjustment cross-section JQ varies in the tangential direction and has, in some sections, areas of reduced diameter, each located between two tangentially adjacent bump-shaped adjustment sections JS.

[0028] The shape of the humps and the outer contour of the drive body 40 in the adjustment cross-section JQ are preferably continuously differentiated to avoid edge formation and the risk of breakage. In the exemplary embodiment, the hump-shaped adjustment sections JS of the drive body 40 are as follows: Fig. 3 or 4 arranged rotationally symmetrically around the central axis of the drive body 40.

[0029] The alignment device 100 aligns the drive body 40 such that, in the area between the alignment device 100 and the drive wheel 30, the central axis of the drive body 40 is concentric to that of the feed tube 10 - apart from a certain amount of play - and lies in a predetermined steering plane of the drive wheel 30.

[0030] To achieve a leakage of the drive body 40 and to allow axial gas flow around the outside of the drive body 40, the alignment sections AA are radially larger than the adjustment sections JS, so that an axial channel or clearance remains between the adjustment sections JS and the associated alignment sections. In the areas between the alignment sections AA, i.e., the pressed-in sections EA, the feed tube 10 is also preferably radially larger than the drive body 40.

[0031] In the embodiment shown, the alignment device 100 forms Fig. 3 or 4 also a stop area which is dimensioned such that the drive body 40 can pass the alignment device 100, but a pusher element 50 pushing the drive body 40 after ignition of the gas generator 20 (see Fig. 2) is stopped. The thrust element 50 is, in the embodiment according to Fig. 1 spherical. The cross-section of the thrust element 50 is smaller than the cross-section of the feed tube 10, so that the thrust element 50 is free of sealing effect from the outset.

[0032] Referring again to the Fig. Figure 2 shows that a sealing element 60 is mounted on the drive body 40 in the area of ​​the end 401 of the drive body 40 facing the gas flow to the gas generator 20. The sealing element 60, together with the drive body 40, is pushed by the thrust element 50 into the stop area formed by the alignment device 100, or even completely or partially through it. In the embodiment according to Fig. 2. The sealing element 60 and the end of the drive body 40 facing the gas flow to the gas generator 20 remain completely within the alignment device 100. Alternatively, the sealing element 60 can be completely or at least partially pushed out of or through the alignment device 100.

[0033] The sealing element 60 serves to seal the feed pipe 10 against gas flow before it reaches the alignment device 100, preventing the gas G from the gas generator 20 from passing through the sealing element 60 in the direction of gas flow. Upon entering the alignment device 100, the sealing element 60 loses its sealing function due to the formation of gas flow channels near the sealing element, allowing the gas G from the gas generator 20 to pass through. This loss of sealing function is due to the design, specifically the shape of the inner wall area, of the alignment device 100.

[0034] The formation of the gas flow channels near the sealing element is based, for example, on the fact that the sealing element 60 is irreversibly destroyed in its sealing function by deformation upon penetration into the alignment device 100. Such irreversible destruction can occur, for example, through deformation or compression of the sealing element and / or through shearing off sections. Shearing can be caused by the radially smaller or tapered cross-sectional areas EA of the feed tube 10, which also serve to stop the thrust element 50.

[0035] The Fig. 2 recognize that a non-sealing, axially spring-loaded spring element 70 can be arranged between the thrust element 50 and the gas generator 20, which can serve to prevent axial play of the parts and thus rattling noises before the gas generator is triggered.

[0036] With regard to the manufacture of the drive body 40, it is considered advantageous if the adjustment cross-section JQ varies in the axial direction and is provided with pockets T in partial sections. An advantageous embodiment of the drive body 40 with pockets T is described in the Fig. 5 shown in more detail.

[0037] In the embodiment according to Fig. 5 Each of the pockets T is arranged between two tangentially adjacent, convex, in particular hump-shaped, adjustment sections JS. While the adjustment sections JS extend axially continuously along the entire second drive section 42 to ensure continuous alignment of the drive body during the tightening process, the pockets T are separated from each other in the axial direction by pocket-free sections.

[0038] Finally, it should be mentioned that the features of all the embodiments described above can be combined with each other in any way to form further embodiments of the invention.

[0039] Furthermore, all features of dependent claims can be combined individually with each of the subordinate claims, either individually or in any combination with one or more other dependent claims, to obtain further embodiments. Reference symbol list 1. Tightener drive 2 belt reels 3 seatbelt retractors 10 feed pipe 10a closed pipe section 10b Gutter section 10c transformed section 11 End 20 Gas generator 30 drive wheel 40 drive units 40a Head section 40b Stem section 41 Drive section 42 Drive section 50 shear element 60 sealing element 70 spring element 100 alignment device 110 Alignment ramp 111 convex section 400 concave constriction 401 End AA alignment section EA dented section G Gas JQ adjustment cross-section JS Adjustment Section SA Mushroom mirror axis T-bag IV-IV section line

Claims

A tensioner drive (1) for a belt retractor (3) with a feed tube (10) and a gas generator (20) attached to one end of the feed tube (10), which feeds gas (G) into the feed tube (10) after ignition, wherein a drive body (40) is arranged downstream of the gas generator (20) - viewed in the direction of gas flow, characterized in that - the cross-section of the feed tube (10) is larger than the cross-section of the drive body (40) and the drive body (40) has play within the feed tube (10), - the drive body (40) has at least sectionally an adjustment cross-section (JQ) that deviates from a circular cross-section, and - an alignment device (100) is arranged between the gas generator (20) and the drive wheel (30), which interacts with the adjustment cross-section (JQ) of the drive body (40) and ensures a predetermined alignment and target position of the forcees the drive body (40) relative to the drive wheel (30). Tightener drive (1) according to claim 1, characterized in that the adjustment cross-section (JQ) has at least two adjustment sections (JS) which each interact with a corresponding, inversely shaped alignment section (AA) of the alignment device (100). Tightener drive (1) according to claim 2, characterized in that the at least two adjustment sections (JS) of the drive body (40) are each concave or convex. Tightener drive (1) according to one of the preceding claims, characterized in that the alignment sections (AA) are radially larger than the adjustment sections (JS) and an axial channel remains between the adjustment sections (JS) and the associated alignment sections (AA), which would allow an axial gas flow past the drive body (40). Tightener drive (1) according to one of the preceding claims, characterized in that the outer contour of the drive body (40) is continuously differentiable in the adjustment cross-section (JQ). Tightener drive (1) according to one of the preceding claims, characterized in that the adjustment sections (JS) are bump-shaped. Tightener drive (1) according to one of the preceding claims, characterized in that - the drive body (40) has at least three adjustment sections (JS) which each engage in an associated alignment section (AA) of the alignment device (100), and - the alignment device (100) causes the drive body (40) to be aligned in such a way that in the area between the alignment device (100) and the drive wheel (30) the central axis of the drive body (40) is concentric to that of the feed tube (10) and / or lies in a predetermined control plane of the drive wheel (30). Tightener drive (1) according to one of the preceding claims, characterized in that: - the drive body (40) has three or more, in particular four, radially outwardly curved, bump-shaped adjustment sections (JS), each of which engages in an associated alignment section (AA) of the alignment device (100); - the bump-shaped adjustment sections (JS) of the drive body (40) are arranged rotationally symmetrically about the central axis of the drive body (40); - the alignment sections (AA) of the alignment device (100) are arranged concavely and rotationally symmetrically about the central axis of the feed tube (10); and - the alignment device (100) aligns the drive body (40) such that, in the area between the alignment device (100) and the drive wheel (30), the central axis of the drive body (40) is concentric with that of the feed tube (10) and / or in a predetermined The steering level of the drive wheel (30) is located. Tightener drive (1) according to one of the preceding claims 1 to 5, characterized in that: - the drive body (40) has a mushroom-shaped cross-section, a head section (40a) and a stem section (40b), and is axially symmetrical about a mushroom mirror axis (SA); - the stem section (40b) has two concave constrictions (400) which are arranged axially symmetrically to each other with respect to a mushroom mirror axis (SA); - the alignment device (100) has two convex sections (111) which engage in the concave constrictions (400); and - the convex sections (111) cause the drive body (40) to be aligned such that, in the area between the alignment device (100) and the drive wheel (30), the mushroom mirror axis (SA) passes through the center point of the feed tube (10) and / or is located in a predetermined target control plane of the drive wheel (30) is located. Tightener drive (1) according to one of the preceding claims, characterized in that - the drive body (40) has a first drive section (41) which is arranged at an end of the drive body (40) facing the drive wheel (30) and engages in the drive wheel (30) as the first section of the drive body (40) after the gas generator (20) is triggered, and has a second drive section (42) which is directly or indirectly connected thereto, - the cross-section of the first drive section (41) differs from the cross-section of the second drive section (42) and is preferably round, and - the second drive section (42) of the drive body (40) has the adjustment cross-section (JQ) mentioned above. Tightener drive (1) according to one of the preceding claims, characterized in that the drive body (40) is already partially in the alignment device (100) in the starting position before the gas generator (20) is triggered. Tightener drive (1) according to one of the preceding claims, characterized in that - the adjustment cross-section (JQ) varies in the axial direction and is provided with pockets (T) in partial sections, - wherein each of the pockets (T) is arranged between two tangentially adjacent convex, in particular hump-shaped, adjustment sections (JS). Tightener drive (1) according to one of the preceding claims, characterized in that the alignment device (100) is formed by a deformed, preferably by a press-fit method, section of the feed tube (10) or at least also comprises such a deformed section. Tightener drive (1) according to one of the preceding claims, characterized in that - the feed tube (10) has a closed tube section (10a) to which the gas generator (20) is connected at one end and to which a one-piece molded channel section (10b) is connected, into which the drive wheel (30) engages from the outside, and - the alignment device (100) comprises an alignment element (110) which is mounted in the channel section (10b) - viewed in the direction of drive - in front of the drive wheel (30). Tightener drive (1) according to claim 14, characterized in that the alignment element is an alignment ramp (110) which is placed on the inside of the channel section (10b). A tensioner drive (1) according to one of the preceding claims, characterized in that – viewed in the direction of gas flow of the gas (G) – the drive body (40) and a thrust element (50), which pushes the drive body (40) after ignition of the gas generator (20), are arranged downstream, – a sealing element (60) is arranged upstream of the thrust element (50) viewed in the direction of gas flow, – the alignment device (100) forms a stop area which is dimensioned such that the drive body (40) can pass through the stop area, but the thrust element (50) is stopped, and – the sealing element (60) reaches the stop area upstream of the thrust element (50), seals the supply tube (10) against gas flow before reaching the stop area and becomes non-sealing upon entering the alignment device (100) and allows the gas (G) of the gas generator (20) to pass through. Belt winder (3) with tensioner drive (1), characterized in that - the tensioner drive (1) is a tensioner drive (1) according to one of the preceding claims and - the drive wheel (30) of the tensioner drive (1) is directly or indirectly connected to a belt spool (2) of the belt winder (3) and - driven by a movement of the drive body (40) past the drive wheel (30) - can be set into a rotational movement along a direction of rotation corresponding to the winding direction of the belt winder (3).

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