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 (11) of the feed tube (10), which feeds gas (G) into the feed tube (10) after ignition, wherein - the feed tube (10) is provided with a stop area (13) at or in the area of ​​its other end (12), - the gas generator (20) - viewed in the direction of gas flow of the gas (G) - a drive body (40) and a thrust element (50), which pushes the drive body (40) after ignition of the gas generator (20), are arranged downstream and - the stop area (13) is dimensioned such that the drive body (40) can pass through the stop area (13), but the thrust element (50) is stopped, characterized in that - in the stopped position of the thrust element (50) at least one gas flow channel (G50) close to the thrust element remains between it and the inner wall of the feed tube (10), through which the gas (G) of the gas generator (20) can pass the stopped thrust element (50), and - a sealing element (60) is arranged in the direction of gas flow in front of the thrust element (50) and thus reaches the stop area (13) in front of the thrust element (50), seals the supply pipe (10) in terms of gas flow before reaching the stop area (13) and becomes non-sealing upon entering the stop area (13) and allows the gas (G) of the gas generator (20) to pass through.

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 according to the features of the preamble of claim 1 is known, for example, from US patent US 9,555,768 B2. Other tensioner drives are disclosed in German patent applications DE 10 2013 210 766 A1 and WO 2021 / 153022 A1.

[0002] In the previously known tensioning drive, the feed tube is provided with a stop section at its other end. Downstream of the gas generator—viewed in the direction of gas flow—are a drive element and a thrust element, which, after ignition of the gas generator, propels the drive element. The stop section is dimensioned such that the drive element can pass through it, but the thrust element is stopped. In the previously known tensioning drive, the feed tube remains pressurized even after the tensioning process is complete.

[0003] The invention is based on the objective of further developing a tensioner drive of the type described above.

[0004] 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.

[0005] According to the invention, it is provided that in the stopped position of the thrust element, at least one gas flow channel close to the thrust element remains between it and the inner wall of the feed pipe, through which the gas of the gas generator can pass the stopped thrust element, and a sealing element in front of the thrust element reaches the stop area, seals the feed pipe against gas flow before reaching the stop area and becomes non-sealing upon entering the stop area, allowing the gas of the gas generator to pass through.

[0006] A significant advantage of the tensioning drive according to the invention is that the thrust element is retained by the stop zone in the supply tube and cannot leave the supply tube. Despite the retention of the thrust element, however, unlike, for example, the previously mentioned known tensioning drive, the design according to the invention ensures that the supply tube becomes depressurized after the thrust element stops, because the sealing element is located upstream of the thrust element in the direction of gas flow and loses its sealing effect upon entering or passing through the stop zone.

[0007] In an advantageous embodiment of the tensioner drive, the cross-section of the feed tube in the stop region is radially smaller in at least one cross-sectional area than the cross-section before the stop region. This radially smaller cross-sectional area can serve to stop the thrust element; furthermore, it can cause deformation, for example, irreversible deformation or total or partial destruction of the sealing element.

[0008] The radially smaller cross-sectional areas can be formed, for example, by mechanically machining the feed pipe, by pressing it in or tapering it section by section. In such a case, the radially smaller cross-sectional areas can also be referred to as mechanically tapered cross-sectional areas. The radially smaller cross-sectional areas can, for example, form beads.

[0009] It is advantageous if at least two radially smaller cross-sectional areas are present. The radially smaller cross-sectional areas are preferably arranged rotationally symmetrically.

[0010] It can also be advantageously provided that the cross-section of the feed pipe in the stop region is radially larger in at least one cross-sectional area than the cross-section before the stop region. This at least one radially larger cross-sectional area can additionally serve to guide a gas flow tangentially past the sealing element, thereby further promoting the leakage of the sealing element. This at least one radially larger cross-sectional area can also radially limit the gas flow channel, or at least a section thereof, located near the shear element.

[0011] The radially larger cross-sectional area(s) can be formed, for example, by mechanically machining the feed pipe, thereby widening it section by section. In such a case, the radially larger cross-sectional area(s) can also be referred to as mechanically widened cross-sectional areas.

[0012] It is advantageous if at least two radially larger cross-sectional areas are present. The radially larger cross-sectional areas are preferably arranged rotationally symmetrically.

[0013] It is considered advantageous if the gas from the gas generator can pass through the sealing element via at least one gas flow channel near the sealing element, which is bounded by the outer wall of the sealing element and the inner wall of the supply pipe in the stop region, and exit the supply pipe. For example, the aforementioned radially larger cross-sectional area can limit the gas flow channel near the sealing element radially outwards.

[0014] When the thrust element is stopped, the sealing element can remain entirely or at least partially within the stop area or be pushed through it.

[0015] If the sealing element is pushed completely or at least partially through the stop area by the thrust element, it is considered advantageous if the cross-section of the feed tube in the area between the stop area and the other end of the feed tube is shaped differently than the cross-section of the sealing element after it has been pressed through the stop area, thereby forming at least one gas flow channel near the sealing element, which is bounded by the outer wall of the sealing element and the inner wall of the feed tube in the area between the stop area and the other end of the feed tube and through which the gas from the gas generator can pass in the direction of the other end of the feed tube.

[0016] As already mentioned, the sealing element is destroyed in its sealing function upon penetration into the stop zone due to a change in shape, preferably irreversibly. It is advantageous if a radially outer section of the sealing element is sheared off upon penetration into the stop zone.

[0017] If the cross-section of the sealing element has been reduced by such an irreversible change in the stop area, the cross-section of the feed pipe behind the stop area and the cross-section of the feed pipe before the stop area can be identical; otherwise, or generally, the cross-section of the feed pipe behind the stop area can be larger than the cross-section of the feed pipe before the stop area.

[0018] The drive body is preferably smaller than the cross-section of the feed tube, at least after passing the stop area, and therefore has no sealing effect.

[0019] The thrust element is, or preferably becomes, at least upon reaching the stop range, free of any sealing effect.

[0020] The sealing element can be attached to the drive body or molded in one piece; alternatively, the sealing element can be arranged as a separate component between the drive body and the thrust body.

[0021] In a further embodiment considered advantageous, a non-sealing spacer is arranged between the sealing element and the drive body.

[0022] In the latter embodiment, it is advantageous if the longitudinal extent of the spacer body – viewed in the longitudinal direction of the feed tube – is dimensioned so large that, when the thrust element is stopped, the drive body is at least pushed out of the stop area of ​​the feed tube. Preferably, the spacer body pushes the drive body completely out of the drive tube.

[0023] The sealing element and the spacer body are preferably coupled together, in particular connected to each other by a clip connection.

[0024] It is also particularly advantageous, especially to avoid rattling noises in the ground state before the tensioner drive is triggered, if a non-sealing, axially resilient spring element is arranged between the thrust element and the gas generator, the cross-section of which is shaped in such a way that at least one gas flow channel close to the spring element is present between the inner wall of the supply tube and the outer wall of the spring element, through which the gas can pass the spring element in the direction of the other end of the supply tube.

[0025] The spring element is preferably formed by a one-piece plastic body.

[0026] The drive body is preferably a deformable drive rod.

[0027] The thrust element is preferably a ball.

[0028] In the stopped position of the thrust element, the gas from the gas generator can preferably leave the supply tube at its other end, so that the supply tube becomes depressurized after completion of the tightening process.

[0029] 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.

[0030] The invention is explained in more detail below with reference to exemplary embodiments; the following are shown as examples: Fig. 1 Components of a first embodiment of a tensioner drive according to the invention, with which a belt spool of a belt winder comprising the tensioner drive can be driven in the belt winding direction, Fig. 2a-2c advantageous embodiments of the cross-section of a supply tube of the tensioner drive according to Fig. 1 in a stop-loss zone, Fig. 3 an advantageous embodiment of a spring element of the tensioner drive according to Fig. 1 and Fig. 4 Components of a second embodiment of a tensioner drive according to the invention.

[0031] For the sake of clarity, the same reference symbols are always used in the figures for identical or comparable components.

[0032] The Fig. Figure 1 shows components of a first embodiment for 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.

[0033] 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.

[0034] In the embodiment according to Fig. 1. The drive body 40 is a single piece and is formed by a deformable drive rod; alternatively, the drive body 40 can be multi-part and formed by two or more drive elements that are connected or unconnected to each other. A multi-part drive body 40 can, for example, be formed by a plurality of loosely connected drive balls.

[0035] The cross-section of the drive body 40 is smaller than the cross-section of the feed tube 10, so that the drive body 40 is free of any sealing effect from the outset.

[0036] In the representation according to Fig. Figure 1 shows the state of the tensioner drive 1 after the end of the tensioning process, such that the drive body 40 has largely left the feed tube 10 and passed the drive wheel 30.

[0037] The feed tube 10 is provided at its other end 12 with a stop section 13, which is dimensioned such that the drive body 40 can pass through the stop section 13, but a pusher element 50 that pushes the drive body 40 after ignition of the gas generator 20 is stopped. In the exemplary embodiment shown, the pusher element 50 is Fig. 1 spherical.

[0038] The cross-section of the thrust element 50 is smaller than the cross-section of the feed pipe 10, so that the thrust element 50 is free of sealing effect from the outset.

[0039] The Fig. Figure 1 also shows that a sealing element 60 is mounted on the drive body 40 in the region of the end 41 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 13 or even completely or partially through it. In the embodiment according to Fig. 1. The sealing element 60 and the end 41 of the drive body 40 facing the gas flow to the gas generator 20 remain completely within the stop area 13. Alternatively, the sealing element 60 can be completely or at least partially pushed out of or through the stop area.

[0040] The sealing element 60 serves to seal the feed pipe 10 against gas flow before it reaches the stop zone 13, 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 stop zone 13, the sealing element 60 loses its sealing function and allows the gas G from the gas generator 20 to pass through. This loss of sealing function is due to the design, for example, the shape of the inner wall area of ​​the stop zone 13.

[0041] Thus, in the exemplary embodiment according to Fig. 1 provided that the gas G of the gas generator 20 passes through the sealing element 60 via gas flow channels G60 near the sealing element (see Fig. 2a and Fig. 2b), which are each bounded by the outer wall of the sealing element 60 and the inner wall of the feed pipe 10 in the stop area 13, can pass through and exit the feed pipe 10. For this purpose, the cross-section of the feed pipe 10 in the stop area 13 is larger in certain sections than the cross-section of the sealing element 60.

[0042] The Fig. Figure 2a shows a first exemplary embodiment of the gas flow channels G60 near the sealing element, which is based on a partial radial expansion of the supply pipe 10 in radially expanded cross-sectional areas RA10 of the supply pipe 10. Specifically, in the embodiment according to Fig. 2a provided that in the area of ​​the gas flow channels G60 or in the area of ​​the radially widened cross-sectional areas RA10 the cross-section of the supply pipe 10 is section by section radially larger than the cross-section of the supply pipe 10 in the direction of gas flow before the stop area 13 in order to form the gas flow channels G60 near the sealing element, and section by section in radially tapered cross-sectional areas RV10 is radially smaller than the cross-section of the supply pipe 10 before the stop area 13 in order to form a stop for the push element 50 which the push element 50 cannot pass.

[0043] The radially larger or radially expanded cross-sectional areas RA10 of the feed pipe 10 can be produced by expanding it using an expanding tool. The radially smaller or radially tapered cross-sectional areas RV10 of the feed pipe 10 can be produced by compression.

[0044] The Fig. Figure 2b shows a second exemplary embodiment of the stop area 13 without radially larger or radially widened cross-sectional areas RA10; instead of the radially larger or radially widened cross-sectional areas RA10, undeformed cross-sectional areas RN10 are present in which the feed pipe 10 has the same inner diameter as the cross-section of the feed pipe 10 before the stop area 13.

[0045] The existence of the gas flow channels G60 near the sealing element is based in the Fig. 2b that the sealing element 60 is irreversibly destroyed in its sealing function by deformation upon penetration into the stop area 13. Such irreversible destruction can occur, for example, through deformation or compression of the sealing element (as in the Fig. 2b) and / or by shearing off sections. Shearing can be caused by the radially smaller or tapered cross-sectional areas RV10 of the feed tube 10, which also serve to stop the thrust element 50.

[0046] In the embodiment according to Fig. 2b The radially smaller or radially tapered cross-sectional areas RV10 deform the sealing element 60 in such a way that it no longer has a sealing function even in the undeformed cross-sectional areas RN10 of the feed pipe 10, because the sealing element 60 no longer has contact with the inner wall of the feed pipe 10 in the undeformed cross-sectional areas RN10. In the undeformed cross-sectional areas RN10 of the feed pipe 10, it preferably has the same inner diameter as the cross-section of the feed pipe 10 before the stop area 13.

[0047] An irreversible change in shape of the sealing element 60 is particularly advantageous if the sealing element 60 is pushed out of the stop area 13 after the end of the tightening process and the pipe section of the feed pipe in the pipe area behind the stop area 13, i.e. between the stop area 13 and the other end 12 of the feed pipe 10, has the same cross-section (or the same size and shape in cross-section) as in the pipe area before the stop area 13; because the sealing element 60 should not be able to have a sealing function in the pipe area behind the stop area 13 either.

[0048] The Fig. Figure 2c shows, for comparison, the thrust element 50 when in contact with the stop area 13 according to Fig. 2a or 2b. It can be seen that the radially smaller cross-sectional areas RV10 of the supply pipe 10 stop the thrust element 50 and the gas flow channels G50 near the thrust element are limited by the radially larger or radially widened cross-sectional areas RA10 of the supply pipe 10 or the undeformed cross-sectional areas RN10 of the supply pipe 10.

[0049] Referring again to Fig. Figure 1 shows that a non-sealing, axially resilient spring element 70 is arranged between the thrust element 50 and the gas generator 20. To ensure that the spring element 70 cannot perform a sealing function, its cross-section is shaped such that at least one gas flow channel G70 close to the spring element exists between the inner wall of the feed tube 10 and the outer wall of the spring element 70 (see Figure 1). Fig. 3) is present, through which the gas G can pass the spring element 70 in the direction of the other end 11 of the supply tube 10.

[0050] The Fig. Figure 3 shows the spring element 70 according to Fig. 1 in more detail. Radial, channel-shaped depressions V70 can be seen, which extend axially over the entire length of the spring element 70 and together with the inner wall of the supply tube 10 form the aforementioned gas flow channels G70 near the spring element.

[0051] The spring element 70 can be formed by a one-piece plastic body.

[0052] The Fig. Figure 4 shows components of a second embodiment for 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.

[0053] The second embodiment according to Fig. 4 corresponds to the first embodiment according to Fig. 1 with two differences, namely firstly, that the sealing element 60 is not attached to or molded onto the drive body 40, but forms a separate part between the drive body 40 and the push element 50, and secondly, that a non-sealing spacer body 80 is arranged between the drive body 40 and the sealing element 60.

[0054] The cross-section of the spacer body 80 is dimensioned to be smaller than the cross-section of the feed pipe 10, so that the spacer body 80 is free of sealing effect from the outset.

[0055] The longitudinal extent of the spacer body is dimensioned – in the longitudinal direction of the feed tube 10 – so that when the thrust element 50 is stopped, the drive body 40 is completely pushed out of the stop area 13 of the feed tube 10.

[0056] The sealing element 60 can also be completely pushed out of the stop area 13 or, as in the Fig. 4 shown, remain entirely or partially within the stop zone 13.

[0057] If the sealing element 60 remains partially within the stop area 13, the leakage of the sealing element 60 within the stop area 13 can be caused by the shape of the feed pipe, as described above in connection with the Fig. 2a and Fig. 2b is shown as an example.

[0058] If the sealing element 60 is completely pushed out of the stop area 13, the radially smaller sections have a dual function because they form a stop for the thrust element 50 to stop it, and cause an irreversible deformation of the sealing element 60, for example by shearing.

[0059] The leakage of the shear element 50 or the existence of the gas flow channels G50 near the shear element can be ensured in the absence of radially larger sections in the stop area 13 by selecting the cross-section of the shear element 50 to be correspondingly small and shaped in such a way that, even when the shear element 50 is in contact with the stop area 13, overlap-free cross-sectional areas remain despite the radially smaller sections.

[0060] To ensure that the sealing element 60 cannot exert a sealing effect behind the stop area 13, the cross-section of the feed tube 10 in the area between the stop area 13 and the other end 12 of the feed tube 10 can be shaped differently than the cross-section of the sealing element 60 after it has been pressed through the stop area 13.

[0061] The different design of the cross-sections of sealing element 60 and feed pipe 10 behind the stop area 13 may be due to - solely on the shape of the cross-section of the feed tube 10 behind the stop area 13, by equipping the feed tube 10, for example, with radially larger sections, as is done in the Fig. 2a was explained in connection with stop zone 13, - solely on an irreversible deformation of the sealing element 60 when passing the stop area 13 or - on both of the aforementioned measures.

[0062] The measures mentioned above ensure that at least one gas flow channel G60 close to the sealing element remains in the area between the stop area 13 and the other end 11 of the supply pipe 10, which is limited by the outer wall of the sealing element 60 and the inner wall of the supply pipe 10 and through which the gas G of the gas generator 20 can pass the sealing element 60 in the direction of the other end 11 of the supply pipe 10.

[0063] The sealing element 60 and the spacer 80 can be separate parts that rest loosely against each other. Alternatively, the sealing element 60 and the spacer 80 can be coupled together, in particular connected by a clip connection. For clarity, such a clip connection is shown in the Fig. 4 not shown in detail.

[0064] Regarding the remaining design of the second embodiment according to Fig. 4, in particular with regard to the design of the sealing element 60 and the spring element 70, the above statements can be made in connection with the Fig. 1 for the second embodiment according to Fig. 4 apply accordingly.

[0065] The two exemplary embodiments according to the Fig. 1 and Fig. 4 is common in that in the stopped position of the thrust element 50 the gas G of the gas generator 20 can leave the supply tube 10 at its other end 12 and the supply tube 10 becomes depressurized because the initially sealing sealing element 60 becomes non-functional and the drive body 40, the thrust element 50 and the spring element 70 have no sealing function from the beginning or even before the start of the tightening process and before the ignition of the gas generator 20.

[0066] When the gas generator 20 is ignited, the gas G of the gas generator 20 pushes the spring element 70 and the thrust element 50 towards the other end 12 of the feed tube 10, thereby pushing the drive body 40 out of the feed tube 10 and driving the drive wheel 30 of the tensioner drive 1. The drive wheel 30 is connected directly or indirectly to the belt spool 2 and is set into a rotational motion – driven by the movement of the drive body 40 past the drive wheel 30 – along a direction of rotation corresponding to the winding direction of the belt winder 3.

[0067] 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.

[0068] 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 11 End 12 End 13 Stop range 20 Gas generator 30 drive wheel 40 drive units 41 End of the drive unit 50 shear element 60 sealing element 70 spring element 80 spacers G Gas G50 thrust element-proximal gas flow channel G60 gas flow channel near sealing element G70 gas flow channel near spring element RA10 radially larger (e.g. widened) cross-sectional area RN10 radially unchanged cross-sectional area RV10 radially smaller (e.g. tapered) cross-sectional area V70 recesses

Claims

A tensioner drive (1) for a belt retractor (3) with a feed tube (10) and a gas generator (20) attached to one end (11) of the feed tube (10), which feeds gas (G) into the feed tube (10) after ignition, wherein: - the feed tube (10) is provided with a stop region (13) at or in the region of its other end (12), - a drive body (40) and a thrust element (50), which pushes the drive body (40) after ignition of the gas generator (20), are arranged downstream of the gas generator (20) - viewed in the direction of gas flow of the gas (G), and - the stop region (13) is dimensioned such that the drive body (40) can pass through the stop region (13), but the thrust element (50) is stopped, characterized in that - in the stopped position of the thrust element (50) between it and the inner wall of the at least one gas flow channel (G50) close to the thrust element remains in the feed tube (10),through which the gas (G) of the gas generator (20) can pass the stopped thrust element (50), and a sealing element (60) is arranged in the direction of gas flow upstream of the thrust element (50) and thus reaches the stop zone (13) upstream of the thrust element (50), seals the feed pipe (10) against gas flow before reaching the stop zone (13) and becomes non-sealing upon entering the stop zone (13) and allows the gas (G) of the gas generator (20) to pass through. Tightener drive (1) according to claim 1, characterized in that the cross-section of the feed tube (10) in the stop area (13) is radially smaller in at least one cross-sectional area (RV10) than the cross-section - seen in the direction of gas flow - before the stop area (13). Tightener drive (1) according to one of the preceding claims, characterized in that the gas (G) of the gas generator (20) can pass through the sealing element (60) through at least one gas flow channel (G60) near the sealing element, which is limited by the outer wall of the sealing element (60) and the inner wall of the supply tube (10) in the stop area (13), and can leave the supply tube (10). Tightener drive (1) according to one of the preceding claims 2 to 3, characterized in that the cross-section of the feed tube (10) in the stop area (13) is radially expanded in at least one cross-sectional area (RA10) and the radially expanded cross-sectional area (RA10) radially limits the at least one gas flow channel (G50) near the thrust element and / or the at least one gas flow channel (G60) near the sealing element. Tightener drive (1) according to one of the preceding claims, characterized in that before or upon reaching its stopped position the thrust element (50) has pushed the sealing element (60) at least sectionally through the stop area (13). Tightener drive (1) according to claim 5, characterized in that - the cross-section of the feed tube (10) in the area between the stop region (13) and the other end (12) of the feed tube (10) is shaped differently than the cross-section of the sealing element (60) after the latter has been pressed through the stop region (13), - whereby at least one gas flow channel (G60) near the sealing element is formed, which is bounded by the outer wall of the sealing element (60) and the inner wall of the feed tube (10) in the area between the stop region (13) and the other end of the feed tube (10) and which the gas (G) of the gas generator (20) can pass through in the direction of the other end of the feed tube (10). Tightener drive (1) according to one of the preceding claims, characterized in that the sealing element (60) is irreversibly destroyed in its sealing function by deformation upon penetration into the stop area (13). Tightener drive (1) according to one of the preceding claims, characterized in that a radially outer section of the sealing element (60) is sheared off upon penetration into the stop area (13). Tightener drive (1) according to one of the preceding claims, characterized in that the sealing element (60) is attached to or molded onto the drive body (40). Tightener drive (1) according to one of the preceding claims 1 to 8, characterized in that a non-sealing spacer body (80) is arranged between the sealing element (60) and the drive body (40). Tightener drive (1) according to claim 10, characterized in that the longitudinal extent of the spacer body (80) - viewed in the longitudinal direction of the feed tube (10) - is dimensioned so large that when the thrust element (50) is stopped, the drive body (40) is pushed out at least from the stop area (13) of the feed tube (10), preferably completely out of the feed tube (10). Tightener drive (1) according to one of the preceding claims 10 to 11, characterized in that the sealing element (60) and the spacer body (80) are coupled to each other, in particular connected to each other by a clip connection. Tightener drive (1) according to one of the preceding claims, characterized in that a non-sealing, axially resilient spring element (70) is arranged between the thrust element (50) and the gas generator (20), the cross-section of which is shaped such that at least one gas flow channel (G70) close to the spring element is present between the inner wall of the supply tube (10) and the outer wall of the spring element (70), through which the gas (G) can pass the spring element (70) in the direction of the other end (12) of the supply tube (10). Tightener drive (1) according to claim 13, characterized in that the spring element (70) is formed by a one-piece plastic body. Tightener drive (1) according to one of the preceding claims, characterized in that in the stopped position of the thrust element (50) the gas (G) of the gas generator (20) can leave the supply tube (10) at its other end (12) and the supply tube (10) becomes pressure-free. Belt winder (3) with tensioner drive, characterized in that - the tensioner drive 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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