Gurtaufroller

Abstract

The invention relates to a belt winder with a belt spool (400) for winding and unwinding a belt, a drive (110) and an at least two-stage, load-dependent switching planetary gear (200) between the drive (110) and the belt spool (400), wherein the load-dependent switching of the planetary gear (200) is controlled or at least co-controlled by a clutch pawl (250).According to the invention, the clutch pawl (250) is arranged on a ring gear (240) of the planetary gear (200) and is held resiliently on the ring gear (240), the clutch pawl (250) is in a first pawl position in a first gear of the planetary gear (200) and is rotated with the ring gear (240), engaging a toothing (211) of a drive wheel (210) connected to the drive (110) with the ring gear (240), and the clutch pawl (250) is in a second pawl position in a second gear of the planetary gear (200), in which it disengages the drive wheel (210) from the ring gear (240) and blocks rotation of the ring gear (240).

Description

[0001] The invention relates to a belt winder with a drive and a belt spool for winding and unwinding a webbing strap.

[0002] For example, seatbelt retractors are described in the publications DE 10 2022 101 082 B4, DE 10 2022 133 638 A1 and DE 10 2020 121 236 A1.

[0003] German patent DE 10 2021 113 744 B4 discloses a belt retractor with a two-stage, load-dependent switching planetary gear between the drive and the belt spool. The load-dependent switching of the planetary gear is controlled by a frame-mounted clutch pawl.

[0004] The invention is based on the objective of providing a belt retractor with a load-dependent switching planetary gear unit, which has a particularly compact design.

[0005] This problem is solved according to the invention by a belt retractor with the features according to claim 1. Advantageous embodiments of the belt retractor according to the invention are specified in the dependent claims.

[0006] According to the invention, the clutch pawl is arranged on a ring gear of the planetary gear and is held resiliently on the ring gear, the clutch pawl is in a first pawl position in a first gear of the planetary gear and is rotated with the ring gear, coupling a toothing of a drive wheel connected to the drive with the ring gear, and the clutch pawl is in a second pawl position in a second gear of the planetary gear, in which it disengages the drive wheel from the ring gear and blocks rotation of the ring gear.

[0007] In the belt winder according to the invention, the clutch pawl is advantageously arranged on the ring gear of the planetary gear, which allows for a compact design and easy assembly of the clutch pawls.

[0008] The clutch pawl preferably allows a faster rotational movement of the planet carrier in the first gear of the planetary gear than in the second gear and preferably allows a higher torque transmission in the second gear of the planetary gear than in the first gear.

[0009] The toothing of the drive wheel is preferably internal toothing.

[0010] In one embodiment considered advantageous, a sun gear of the planetary gear forms a drive side of the planetary gear and is rigidly connected directly or indirectly to the drive wheel via an overload coupling, and a planet carrier of the planetary gear forms an output side of the planetary gear and rotates the belt spool when the drive is in operation.

[0011] The toothing of the drive wheel is preferably adapted to the external toothing of the sun gear in such a way that in first gear the ring gear rotates synchronously, i.e. at the same rotational speed, with the sun gear and the planetary gear is operated in direct drive.

[0012] In the second gear of the planetary gear set, the pawl preferably blocks the rotation of the ring gear by engaging with an external, frame-mounted toothing of a seatbelt retractor element. The seatbelt retractor element is preferably the retractor frame of the seatbelt retractor, a part directly or indirectly connected to the retractor frame, such as a plate or another vehicle-mounted component.

[0013] A spring device is preferably attached to the ring gear, for example on the outside or inside, the spring force of which acts on the clutch pawl in the direction of the first pawl position.

[0014] The spring device is preferably a spring ring or a spring clip, the spring force of which acts on the clutch pawl in the direction of the first pawl position.

[0015] Regarding the spring device, it is also advantageous if the clutch pawl is pressed from the first pawl position to the second pawl position by the toothing of the drive wheel against the spring force of the spring device when a drive torque of the drive reaches or exceeds a threshold value defined by the spring force of the spring device.

[0016] It is advantageous if the first pawl end of the clutch pawl engages with a toothed section of the drive gear in the first pawl position and is disengaged from the toothed section in the second pawl position. Adjusting the clutch pawl from the first pawl position to the second pawl position preferably involves pivoting the first pawl end radially inwards.

[0017] It is advantageous if a second pawl end of the coupling pawl is separated from a radially outer, frame-mounted toothing of one of the belt retractor elements described above in the first pawl position and engages with the radially outer, frame-mounted toothing in the second pawl position. Adjusting the coupling pawl from the first to the second pawl position preferably involves pivoting the second pawl end radially outwards.

[0018] The coupling pawl can be a single piece, meaning the two pawl ends can be rigidly connected. Alternatively, the pawl ends can be not rigidly connected, for example via a spring.

[0019] It is particularly advantageous if – for example, by means of a ramp-shaped, preferably rounded, ramp-shaped design of the toothing of the drive wheel – the toothing of the drive wheel slides off the first pawl end of the clutch pawl and the sun gear rotating with the drive wheel – with the assistance of the planet gears of the planetary gear set – forces the ring gear of the planetary gear set into a reverse movement as soon as the drive torque of the drive reaches or exceeds a predetermined threshold value, thereby raising the second pawl end of the clutch pawl and setting the clutch pawl into the second pawl position.

[0020] With a view to a uniform distribution of the coupling forces around the circumference of the ring gear, it is considered advantageous if one or more additional pawls are arranged on the outside of the ring gear of the planetary gear set and are held resiliently against the ring gear. In the first gear of the planetary gear set, these additional pawls are each in a first pawl position and rotate with the ring gear, coupling the teeth of the drive gear to the ring gear. In the second gear of the planetary gear set, these additional pawls are each in a second pawl position, disengaging the drive gear from the ring gear and blocking its rotation. The above statements regarding the single pawl apply accordingly to the additional pawls.

[0021] Preferably, at least two further pawls are arranged on the ring gear. The pawls are preferably arranged rotationally symmetrically on the ring gear.

[0022] Once the tightening process is complete, for example, because an accident has been avoided, the drive can preferably be rotated in the opposite direction, thus re-engaging the planetary gear. The clutch link(s) on the ring gear disengage because the spring mechanism returns them to their initial position. A new tightening process can then begin if necessary.

[0023] Another advantage of the belt retractor designs described above is that the clutch can disengage automatically if the spindle is rotated faster by pyrotechnic tensioning via an additional pyrotechnic tensioner drive than by reversible tensioning via the drive described above. In such a case, the clutch pawl(s) can be disengaged and held in the rest position by the spring mechanism. A switching clutch between the drive and the drive wheel can also be released, so that there is no longer a connection between the belt spool and the drive, allowing the drive wheel to rotate freely; this prevents the seatbelt from overloading the occupant in the event of an accident.

[0024] The invention is explained in more detail below with reference to exemplary embodiments; the following are shown as examples: Fig. 1 Components of an embodiment of a belt retractor according to the invention in a three-dimensional view at an oblique angle from the side, Fig. 2 Components of an exemplary embodiment for a planetary gear for the belt retractor according to Fig. 1, Fig. 3-4 the belt retractor according to Fig. 1 and the planetary gear according to Fig. 2 in a first gear of the planetary gear system, and Fig. 5-6 the belt retractor according to Fig. 1 and the planetary gear according to Fig. 2 in a second gear of the planetary gear system.

[0025] For the sake of clarity, the same reference symbols are always used in the figures for identical or comparable components.

[0026] The Fig. Figure 1 shows components of an exemplary embodiment of a belt retractor according to the invention. In the Fig. Figure 1 shows, among other things, a spur gear stage 100 comprising a drive 110, a spur gear 120, a clutch 130, and a drive pinion 140, a planetary gear 200, and a torsion bar 300, which is connected at its first end 301 to the planetary gear 200 and at its second end 302 to a belt spool 400 suitable for winding and unwinding a belt (not shown). The drive 110 is preferably a reversible electric motor.

[0027] Furthermore, the Fig. 1. Further components such as a spring cassette 500 for generating a torque in the winding direction of the belt spool 400, a spring core 510 connecting the first end 301 of the torsion bar 300 to the spring cassette 500, a belt rewind element 530, a bearing housing 540 and a bearing ring 550. The belt rewind element 530 is preferably a belt rewind frame of the belt rewinder or a part directly or indirectly connected to the belt rewind frame, such as a plate.

[0028] The Fig. Figure 2 shows the planetary gear 200 in more detail. Shown are a drive gear 210, an overload spring forming an overload clutch 220, a sun gear 230, a ring gear 240, three clutch pawls 250, a spring assembly forming a shift spring 260, a retaining ring 270, planet gears 280 and a planet carrier 290.

[0029] In the Fig. Figure 2 shows that the clutch pawls 250 are arranged radially on the outside of the ring gear 240 of the planetary gear 200, preferably rotationally symmetrically, and are held resiliently on the ring gear 240 by the spring device 260. Each of the clutch pawls 250 has a first pawl end 251 and a second pawl end 252, the function of which is explained in more detail below.

[0030] In the first gear of the planetary gear 200, the clutch pawls 250 are each in their first pawl position, in which they rotate with the ring gear 240, thereby engaging the toothing of the drive wheel 210, which is connected to the drive 110, with the ring gear 240; the toothing can be – as shown in the figures – an internal toothing 211 or, alternatively, with a slightly different design, an external toothing. Fig. 3 and Fig. Figure 4 shows the first latch position in more detail.

[0031] In a second gear of the planetary gear 200, the clutch pawls 250 are in their second pawl position, in which they leave the drive wheel 210 disengaged from the ring gear 240, but block rotation of the ring gear 240 by engaging in an external frame-mounted toothing 531 of the belt retractor element 530. Fig. 5 and Fig. Figure 6 shows the first latch position in more detail.

[0032] The clutch pawls 250 enable a faster rotational movement of the planet carrier 290 in their first pawl position or in the first gear of the planetary gear 200 than in their second pawl position or in the second gear of the planetary gear 200, whereas in their second pawl position or in the second gear of the planetary gear 200 they ensure a higher torque transmission than in their first pawl position or in the first gear.

[0033] The sun gear 230 forms the following in the planetary gear 200 according to the Fig. 1 and Fig. 2 is a drive side of the planetary gear 200 and is indirectly connected to the drive wheel 210 via the overload clutch 220 for this purpose. The planet carrier 290 of the planetary gear 200 forms an output side of the planetary gear 200 and thus rotates the belt spool 400 when the drive 110 is operating.

[0034] An internal toothing 211 of the drive wheel 210 is provided in the planetary gear 200 according to the Fig. 1 and Fig. 2 adapted to the external teeth of the sun gear 230 in such a way that in the first gear the ring gear 240 rotates synchronously with the sun gear 230, i.e. rotates at the same rotational speed, so that the planetary gear 200 is operated in so-called direct drive.

[0035] In the second gear of the planetary gear 200, the clutch pawls 250 block the rotation of the ring gear 240 by engaging in an external frame-fixed toothing 531 of the belt retractor element 530, which in the embodiment according to Fig. 1 is arranged in the mounting plate.

[0036] The spring assembly 260, mounted externally on the ring gear 240, can be designed as a spring ring or spring clip, the spring force of which acts on the clutch pawls 250 in the direction of the first pawl position. When, or as soon as, the drive torque of the drive 110 reaches or exceeds a threshold value defined by the spring force of the spring assembly 260, the clutch pawls 250 are pressed from the first pawl position to the second pawl position by the internal teeth 211 of the drive gear 210, against the spring force of the spring assembly 260.

[0037] The clutch pawls 250 each have the aforementioned first pawl end 251, which engages in the internal teeth 211 of the drive wheel 210 in the first pawl position (see Fig. 3 and Fig. 4) and is separated from the internal teeth 211 in the second pawl position (see Fig. 5 and Fig. 6) In the embodiment shown in the figures, adjusting the clutch pawl 250 from the first pawl position to the second pawl position thus includes pivoting the first pawl end 251 radially inwards about a fixed or movable pivot axis 253.

[0038] The coupling pawls 250 also each have the aforementioned second pawl end 252, which in the first pawl position is separated from the radially outer frame-fixed toothing 531 of the belt retractor element 530 (see Fig. 3 and Fig. 4) and engages in the radially outer frame-fixed toothing 531 in the second pawl position (see Fig. 5 and Fig. 6) In the embodiment shown in the figures, adjusting the coupling pawls 250 from the first pawl position to the second pawl position therefore includes pivoting the second pawl end 252 radially outwards.

[0039] In the embodiment shown in the figures, the clutch pawls 250 are designed and arranged such that the internal toothing 211 of the drive wheel 210 slides off the first pawl end 251 of the clutch pawls 250 and the sun gear 230, which rotates with the drive wheel 210, forces the ring gear 240 of the planetary gear 200 into a reverse movement as soon as the drive torque of the drive 110 reaches or exceeds the predetermined threshold value, thereby lifting the second pawl end 252 of the clutch pawls 250 and moving the clutch pawls 250 into the second pawl position.

[0040] Once the tightening process is complete, for example, because an accident has been avoided, the drive 110 can be rotated in the opposite direction, thereby re-engaging the planetary gear 200. The clutch links 250 on the ring gear 240 then disengage because the spring assembly 260, or the shift spring, pulls them back into their initial position. A new tightening process can then begin if necessary.

[0041] A further advantage of the embodiment described above is that the planetary gear 200 switches automatically when the belt reel 400 is tightened more quickly by pyrotechnic tensioning via a pyrotechnic tensioning drive (not shown in the figures) than by reversible tensioning via the drive shown in the figures. Fig.The drive 110 shown in Figures 1-6 is rotated. In such a case, the clutch pawls 250 are disengaged and held in the rest position by the spring assembly 260 or the switching spring. The switching clutch 130 is also released in the first stage, so that there is no longer a connection between the belt spool 400 and the drive 110, and the drive wheel 210 can rotate freely; this prevents the belt from overloading the occupant in the event of an accident.

[0042] In the embodiment shown in the figures, the two latch ends 251 and 252 of the coupling latches 250 are each rigidly connected to each other; alternatively, the latch ends 251 and 252 can also be not rigidly coupled to each other, for example via a spring.

[0043] Finally, it should be mentioned that the features of all the above-described embodiments can be combined with each other in any way to form further other embodiments of the invention.

[0044] 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.

Claims

[1] Seatbelt retractor with - a belt spool (400) for winding and unwinding a webbing strap, - a drive (110) and - a planetary gear unit (200) with at least two stages, switching depending on the load, between the drive (110) and the belt spool (400), - wherein the load-dependent shifting of the planetary gear (200) is controlled or at least co-controlled by a clutch pawl (250), characterized by , that - the clutch pawl (250) is arranged on a ring gear (240) of the planetary gear (200) and is held springily on the ring gear (240), - the clutch pawl (250) is in a first gear of the planetary gear (200) in a first pawl position and is rotated with the ring gear (240), coupling a toothing (211) of a drive gear (210) connected to the drive (110) with the ring gear (240), and - the clutch pawl (250) is in a second gear of the planetary gear (200) in a second pawl position, in which it disengages the drive wheel (210) from the ring wheel (240) and blocks rotation of the ring wheel (240). [2] Belt retractor according to claim 1, characterized by , that - a sun gear (230) of the planetary gear (200) forms a drive side of the planetary gear (200) and is rigidly connected directly or indirectly to the drive gear (210) via an overload clutch (220) and - a planet carrier (290) of the planetary gear (200) forms an output side of the planetary gear (200) and rotates the belt spool (400) when the drive (110) is in operation. [3] Belt retractor according to claim 2, characterized by, that the toothing (211) of the drive wheel (210) is adapted to the external toothing of the sun wheel (230) in such a way that in first gear the ring gear (240) rotates synchronously, i.e. with the same rotational speed, with the sun wheel (230) and the planetary gear (200) is operated in direct drive. [4] Belt retractor according to any of the preceding claims, characterized by , that the clutch pawl (250) in the second gear of the planetary gear (200) blocks the rotation of the ring gear (240) by engaging in an external frame-fixed toothing of a belt retractor element (530). [5] Belt retractor according to any of the preceding claims, characterized by , that a spring device (260) is attached to the ring gear (240), the spring force of which acts on the clutch pawl (250) in the direction of the first pawl position. [6] Belt retractor according to claim 5, characterized by, that the spring device (260) is a spring ring or spring clip whose spring force acts on the clutch pawl (250) in the direction of the first pawl position. [7] Belt retractor according to claim 5 or 6, characterized by , that the clutch pawl (250) is pressed by the toothing (211) of the drive wheel (210) against the spring force of the spring device (260) from the first pawl position to the second pawl position when a drive torque of the drive (110) reaches or exceeds a threshold value defined by the spring force of the spring device (260). [8] Belt retractor according to any of the preceding claims, characterized by , that a first pawl end (251) of the clutch pawl (250) engages in a toothing (211) of the drive wheel (210) in the first pawl position and is separated from the toothing (211) in the second pawl position. [9] Belt retractor according to claim 8, characterized by, that adjusting the clutch pawl (250) from the first pawl position to the second pawl position includes pivoting the first pawl end (251) radially inwards. [10] Belt retractor according to any of the preceding claims, characterized by , that a second pawl end (252) of the coupling pawl (250) is separated in the first pawl position from a radially external frame-fixed toothing (531) of a belt retractor element (530) and engages in the radially external frame-fixed toothing (531) in the second pawl position. [11] Belt retractor according to claim 10, characterized by , that adjusting the clutch pawl (250) from the first pawl position to the second pawl position includes pivoting the second pawl end (252) radially outwards. [12] Belt retractor according to any of the preceding claims, characterized by, that a toothing (211) of the drive wheel (210) slips off a first pawl end (251) of the clutch pawl (250) and a sun gear (230) rotating with the drive wheel (210) - with the assistance of planet gears (280) of the planetary gear set (200) - forces a ring gear (240) of the planetary gear set (200) into a reverse movement as soon as the drive torque of the drive (110) reaches or exceeds a predetermined threshold value, thereby raising a second pawl end (252) of the clutch pawl (250) and moving the clutch pawl (250) into the second pawl position. [13] Belt retractor according to any of the preceding claims, characterized by , that - one or more additional clutch pawls (250) are arranged on the outside of a ring gear (240) of the planetary gear (200) and are held springily on the ring gear (240), - the further clutch pawls (250) are each in a first gear of the planetary gear set (200) in a first pawl position and are rotated with the ring gear (240), each coupling the toothing (211) of the drive gear (210) with the ring gear (240), and - the other clutch pawls (250) are each in the second gear of the planetary gear (200) in a second pawl position, in which they disengage the drive wheel (210) from the ring wheel (240) and block rotation of the ring wheel (240). [14] Belt retractor according to claim 13, characterized by , that - at least two further clutch pawls (250) are arranged on the ring gear (240) and / or - the clutch pawls (250) are arranged rotationally symmetrically on the ring gear (240). [15] Belt retractor according to any of the preceding claims, characterized by, that the coupling pawl (250) or the coupling pawls (250) are each one piece, i.e. the two pawl ends are rigidly connected, or the pawl ends are not rigidly coupled. [16] Belt retractor according to any of the preceding claims, characterized by , that the clutch pawl (250) or clutch pawls (250) in the first gear of the planetary gear (200) enable a faster rotational movement of the planet carrier (290) than in the second gear and enable a higher torque transmission in the second gear of the planetary gear (200) than in the first gear.

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