Safety belt system and method for determining the extracted length of a webbing of a safety belt system wound on a rotatable belt reel

Abstract

The invention relates to a safety belt system (10) having a control unit (14) and a safety belt (16) having a webbing (18) and a belt reel (20). The belt reel (20) comprises a belt reel shaft (28) for the webbing (18), a rotation angle sensor (30) with a sensor unit and a rotatable measuring element, and a transmission mechanism coupling the belt reel shaft (28) with the measuring element. The belt reel shaft (28) has here a fully extracted position and a phantom position. Furthermore, the transmission mechanism is designed such that, when the belt reel shaft (28) is adjusted from the phantom position to the fully extracted position, the transmission mechanism reduces the rotation of the belt reel shaft (28) to a maximum of 1.0 revolution of the measuring element. Furthermore, a method for determining the extracted length of a webbing (18) of a safety belt system (10) wound on a rotatable belt reel shaft (28) is proposed.

Description

Technical Field

[0001] This invention relates to a seatbelt system, particularly a seatbelt system for vehicle seats, comprising a control unit and a seatbelt, the seatbelt having webbing and a belt retractor, the belt retractor having a belt spool for the webbing, a rotation angle sensor with a sensor unit and a rotatable measuring element, and a transmission mechanism having at least one transmission element connecting the belt spool to the measuring element. Furthermore, this invention relates to a method for determining the pull-out length of the webbing wound on the rotatable belt spool in the seatbelt system. Background Technology

[0002] Various devices are known for determining the webbing pull-out length in seatbelt systems with retractors. The determination of the webbing pull-out length is typically based on detecting the rotational position of the reel (on which the webbing is wound). To determine the absolute rotational angle of the reel (which can be greater than 360° from zero), in addition to detecting the angular position of the reel as it has rotated more than one revolution, it is also necessary to be able to detect the number of revolutions in both rotational directions.

[0003] If an incremental or partially absolute measuring device (where only a portion of the total number of reel turns is absolutely detected, such as a range of 0°-360° per turn) is used to detect the reel rotation angle and then summed or incremented, the absolute value of the reel's rotation angle relative to a fixed reference point, particularly the zero point, will be unknown. Furthermore, the previous position information will be lost after the control device performing the detection is turned off and restarted.

[0004] In principle, when using a measuring device that performs detection using an incremental or partially absolute method, at least one reference point can be set up to refer to when identifying the rotation angle of the tape reel detected by the incremental or partially absolute method. The absolute tape reel rotation angle can then be determined over the entire tape reel rotation. The disadvantage of this reference point is that the detected tape reel rotation angle is not absolutely known before the reference point is identified. Summary of the Invention

[0005] The object of the present invention is to determine the current webbing pull-out length as accurately as possible in a seat belt system with a retractor using simple measures (i.e., with minimal expenditure on equipment technology).

[0006] This objective is achieved by a seatbelt system, particularly a seatbelt system for vehicle seats, having a control unit and a seatbelt, the seatbelt having webbing and a belt retractor. The belt retractor has a belt spool for the webbing, a rotation angle sensor with a sensor unit and a rotatable measuring element, and a transmission mechanism connecting the belt spool to the measuring element and having at least one transmission element. The belt spool has a fully extended position (i.e., an angular position of the belt spool corresponding to the maximum achievable amount of webbing extension) and a phantom position (i.e., an angular position of the belt spool corresponding to the minimum achievable amount of webbing extension when the buckle is closed, i.e., when the seatbelt is closed). Here, the transmission mechanism is designed such that when the belt spool is adjusted from the phantom position to the fully extended position, the transmission mechanism reduces the rotation of the belt spool to a maximum of 1.0 turn of the measuring element. By measuring the angular position of the measuring element (i.e., the rotation angle relative to a reference position), the absolute webbing pull-out amount within the range between the fully withdrawn and phantom positions can be determined, since each angular position of the measuring element within this range uniquely corresponds to a specific webbing pull-out length. In particular, this means that the number of turns on the tape reel is not cumulatively detected within this range. This smaller reduction in the total number of tape reel turns (i.e., the range from the fully withdrawn to the minimum withdrawn position) results in higher accuracy compared to systems that reduce the total number of tape reel turns (i.e., from the fully withdrawn to the minimum withdrawn position) to one turn before measurement.

[0007] In the context of this invention, the minimum pull-out position is the angular position of the belt roll corresponding to the minimum amount of webbing that can be pulled out when the buckle is not closed.

[0008] Of course, the seat belt system can have tabs on the seat belt and buckles secured to the vehicle in a known manner.

[0009] To further improve the accuracy of determining the webbing pull-out amount within the range between the fully withdrawn and phantom positions, one embodiment specifies that when the webbing reel is adjusted from the phantom position to the fully withdrawn position, the transmission mechanism reduces the rotation of the reel to more than 0.9 turns, particularly more than 0.95 turns, of the measuring element. In this way, a particularly large angular range can be obtained, within which the webbing pull-out amount can be mapped.

[0010] In one implementation, the transmission element is a measuring element, which allows the belt retractor to be designed to be particularly compact.

[0011] As an alternative, in another implementation, the measuring element can be fixed to the transmission element, particularly directly. This offers manufacturing advantages. Additionally or alternatively, the measuring element and / or transmission element can be designed specifically for their function, especially without requiring design compromises, which is essential for elements that combine the functions of a measuring element and a transmission mechanism.

[0012] Here, the measuring element can be fixed to the last transmission element, thereby maximizing the reduction in conversion ratio between the belt reel and the measuring element. Here, the last transmission element is the transmission element in the work chain opposite to the input transmission element, and particularly the output transmission element of the transmission mechanism.

[0013] In another embodiment, the tape reel has a minimum pull-out position, i.e., an angular position of the tape reel corresponding to the minimum amount of webbing pull-out that can be achieved when the buckle is not closed. Here, the transmission mechanism is designed such that when the tape reel is adjusted from the minimum position to the fully pulled-out position, the transmission mechanism reduces the rotation of the tape reel to more than 1.0 turn and less than 2.0 turns of the measuring element. Therefore, the range between the phantom position and the minimum position can also be mapped to a maximum of one turn of the measuring element, thereby improving the accuracy of measuring the amount of webbing pull-out within this range.

[0014] To ensure exceptionally high measurement accuracy, it is advantageous to reduce the rotation of the tape reel to more than 1.05 turns, and particularly more than 1.10 turns, of the measuring element when the reel is adjusted from its minimum position to its fully extended position. This allows for a correspondingly large angular range within which the tape withdrawal amount can be mapped.

[0015] Additionally or alternatively, in another embodiment, it may be specified that when the tape reel is adjusted from the minimum position to the fully withdrawn position, the drive mechanism reduces the rotation of the tape reel to less than 1.5 turns of the measuring element. Since the amount of tape withdrawn between the minimum and phantom positions is typically less than half the amount withdrawn between the phantom and fully withdrawn positions, particularly high accuracy can be ensured in this way through linear reduction. Furthermore, the drive mechanism with linear reduction is particularly inexpensive.

[0016] Rotation angle sensors can be magnetic sensors, optical sensors, and / or induction-based sensors. These sensors are characterized by high reliability and measurement accuracy, as well as low cost and durability.

[0017] According to one embodiment, the transmission mechanism is a single-stage transmission mechanism, so it can be constructed particularly simply and designed compactly.

[0018] As an alternative, in another embodiment, the transmission mechanism can be a multi-stage transmission mechanism, thus it can be adapted particularly well to different requirements. In particular, specific reductions can be provided more precisely, more compactly, and / or at a lower cost through a multi-stage transmission mechanism.

[0019] According to another embodiment, the seatbelt system has a buckle and a latch for engaging the buckle with the webbing. The buckle is engaged with the webbing via the latch in the closed state. Specifically, the buckle includes a buckle sensor configured to determine whether the buckle is closed, i.e., whether the latch is locked or open. In this way, the state of the buckle can be used as a parameter to determine the amount of webbing pulled out. In particular, a closed buckle means that the amount of webbing pulled out is within the range between the phantom position and the fully pulled-out position, thus this range can be reliably demarcated from the range between the minimum position and the phantom position.

[0020] According to the present invention, in order to achieve the above-mentioned objective, a method is also provided for determining the pull-out length of webbing wound on a rotatable reel of a seatbelt system, wherein the reel has a fully pulled-out position and a phantom position. The following steps are performed here:

[0021] Check whether the latch of the seat belt system is inserted into the buckle of the seat belt system.

[0022] When the latch is inserted into the buckle, the angular position of the measuring element, which is connected to the belt reel via a transmission mechanism, is measured. When the belt reel is adjusted from the phantom position to the fully withdrawn position, the transmission mechanism reduces the rotation of the belt reel to a maximum of 1.0 revolution of the measuring element.

[0023] The pull-out length of the webbing is determined based on the measured angle position.

[0024] This invention is based on the understanding that by determining the angular position of the measuring element, the absolute amount of webbing pulled out in the range between the phantom position and the fully pulled-out position can be determined very accurately with minimal equipment technology costs, wherein each angular position in this range is uniquely equipped with a webbing pull-out length by means of a transmission mechanism.

[0025] The information about buckle closure, i.e., the information about the tongue being inserted into and locked with the buckle, is also used here to determine the pull-out length to ensure that the webbing pull-out amount is within the range between the phantom position and the fully extended position.

[0026] The advantages and features explained for this seatbelt system also apply to this method, and vice versa.

[0027] In one embodiment of the method, when the tape reel is adjusted from the phantom position to the fully withdrawn position, the rotation of the tape reel is reduced to more than 0.9 turns, particularly more than 0.95 turns, of the measuring element. This improves the accuracy of determining the amount of tape withdrawn between the phantom and fully withdrawn positions, because the withdrawn length of the tape in this range is mapped onto a particularly large angular range of the measuring element. Attached Figure Description

[0028] Further advantages and features will become apparent from the following description and accompanying drawings. In these drawings:

[0029] Figure 1 A schematic diagram of a seatbelt system according to the present invention is shown, the seatbelt system having a belt retractor, the belt retractor having a transmission mechanism and a rotation angle sensor, and

[0030] Figure 2 It shows according to Figure 1 A schematic detailed view of the drive mechanism with a retractor and a rotation angle sensor. Detailed Implementation

[0031] exist Figure 1 The image shows a seat belt system 10, which is configured to fasten and thus secure a person or object to the seat 12 provided with the seat belt system 10.

[0032] In the illustrated embodiment, seat 12 is a vehicle seat. However, in principle, seat 12 can be any type of seat.

[0033] Furthermore, the seat belt system 10 is not limited to use in conjunction with the seat 12, but can be set up with any device for securing an object with the seat belt system 10.

[0034] The seat belt system 10 includes: a control unit 14; a seat belt 16 having a webbing 18 and a belt retractor 20 for the webbing 18; a buckle 22; and a tongue 24 that engages with the webbing 18.

[0035] The control unit 14 may be part of the retractor 20, a separate unit in the vehicle, or part of the vehicle's onboard computer.

[0036] The buckle 22 is configured such that when the tongue 24 is inserted into the buckle 22, the tongue 24 locks into the buckle 22. Therefore, the buckle 22 is closed and the tongue 24 is reliably secured to the buckle 22.

[0037] By pressing an unlocking mechanism (not shown), such as a button on buckle 22, buckle 22 is unlocked and latch 24 is released.

[0038] The buckle 22 also has a buckle sensor 26, which is connected to the control unit 14 via signal transmission and is configured to determine the buckle status, i.e. whether the buckle 22 is in a closed state.

[0039] The tape retractor 20 includes: a tape reel 28 configured to provide, i.e., to wind up and unwind the webbing 18; and a sensor unit 32 (see [link to sensor unit]). Figure 2 The rotation angle sensor 30 of the measuring element 34 and the transmission mechanism 36.

[0040] With spool 28 so as to be able to rotate around axis R (see Figure 2 It is supported in a rotating manner in a frame 38 with a retractor 20.

[0041] To ensure that the webbing 18 is always taut, the belt retractor 20 has a belt tensioning device (not shown) that is generally known in the prior art, such as a spring mechanism and / or an electrically driven belt tensioner.

[0042] The buckle status provides information about whether the tongue 24 of the seatbelt 16 is inserted into the buckle 22 for which it is set. If this is the case, it could mean two things: either a certain length of webbing 18 has been pulled out to fasten vehicle occupants, child seats, or other objects to the relevant seat 12 (in... Figure 1 In this case, the outline of the webbing 18 is shown as dashed lines; or the webbing 18 is only minimally pulled out, such that although the latch 24 is inserted into the buckle 22, no person or object is fastened to the associated seat 12. In this case, the webbing 18 extends close to the seat 12 and, in particular, rests against the seat 12 at at least one point. The absolute angle of rotation of the reel 28 corresponding to the minimum amount of webbing 18 pulled out when the latch 24 is inserted into the buckle 22 is called the ghost position.

[0043] Furthermore, the absolute rotation angle of the spool 28 corresponding to the maximum amount of webbing 18 pulled out is called the fully pulled-out position, and the absolute rotation angle of the spool 28 corresponding to the minimum amount of webbing 18 pulled out when the tongue 24 is not inserted is called the minimum position.

[0044] The following reference Figure 2 Explain the structure of the transmission mechanism 36 with the retractor 20.

[0045] In the illustrated embodiment, the transmission mechanism 36 is a two-stage spur gear transmission mechanism having a pinion 40, a first transmission element 42 in the form of a first gear, and a second transmission element 44 in the form of a second gear, wherein the pinion 40 is connected to the second transmission element 44 via the first transmission element 42.

[0046] Here, the second transmission element 44 is the last transmission element in the working chain of the transmission mechanism 36, and the pinion 40 forms the input transmission element.

[0047] Of course, in alternative embodiments, the transmission mechanism 36 may be a single-stage transmission mechanism or a multi-stage transmission mechanism with any number of transmission stages.

[0048] The transmission mechanism 36 is not limited to gear transmission mechanisms, especially pure gear transmission mechanisms.

[0049] In addition, instead of pinion 40, any input transmission element can be provided to input the rotation of the belt reel 28 into the transmission mechanism 36, that is, to connect the belt reel 28 to the transmission mechanism 36.

[0050] The pinion 40 is coaxially oriented with the axis of rotation R and is connected to the tape reel 28 in a non-rotatable manner, so that the rotation of the tape reel 28 about the axis of rotation R is transmitted to the pinion 40 in a 1:1 ratio.

[0051] The transmission mechanism 36 has a transmission ratio such that when the belt reel 28 is adjusted from the phantom position to the fully withdrawn position, the second transmission element 44 rotates by a rotation angle α of 350°.

[0052] In an alternative embodiment, the transmission mechanism 36 may have a different transmission ratio, provided that the second transmission element 44 rotates by a maximum rotation angle α of 360° when the belt reel 28 is adjusted from the phantom position to the fully extended position. This means that when the belt reel 28 is adjusted from the phantom position to the fully extended position, the rotation of the belt reel 28 is reduced to a maximum of 1.0 revolution of the second transmission element 44.

[0053] For example, the transmission mechanism 36 has a transmission ratio such that when the belt reel 28 is adjusted from the phantom position to the fully withdrawn position, the second transmission element 44 rotates by a rotation angle α of at least 324°, and in particular at least 342°.

[0054] Furthermore, the retractable length of the webbing 18 allows the second transmission element 44 to rotate by a rotation angle α of 500° when the belt reel 28 is adjusted from the minimum position to the fully retracted position.

[0055] In principle, when the reel 28 is adjusted from the minimum position to the fully withdrawn position, the second transmission element 44 can rotate by any rotation angle α.

[0056] Preferably, when the belt reel 28 is adjusted from the minimum position to the fully withdrawn position, the second transmission element 44 rotates by a rotation angle α of less than 540°.

[0057] Additionally or alternatively, when the belt reel 28 is adjusted from the minimum position to the fully withdrawn position, the second transmission element 44 can rotate by a rotation angle α greater than 378°, particularly greater than 396°.

[0058] For example, the transmission mechanism 36 has a transmission ratio such that when the belt reel 28 is adjusted from the minimum position to the fully withdrawn position, the second transmission element 44 rotates by a rotation angle α greater than 360° and less than 720°.

[0059] In the illustrated embodiment, the rotation angle sensor 30 is a magnetic sensor.

[0060] The measuring element 34 is formed by two magnetic rotary angle encoders 46 fixed on the second transmission element 44.

[0061] The rotation angle sensor 30 is configured here to determine the angular position of the measuring element 34 by means of the sensor unit 32 and the rotation angle encoder 46, and thereby determine the rotation angle α of the second transmission element 44.

[0062] Such rotation angle sensors 30 are well known, so their structure and function will not be discussed further here.

[0063] The rotation angle sensor 30 can, of course, be designed arbitrarily, especially with any number of rotation angle encoders 46.

[0064] Additionally or alternatively, in another alternative embodiment, the rotation angle sensor 30 may be any sensor used to determine the rotation angle, such as an optical rotation angle sensor or a sensing-based rotation angle sensor.

[0065] It can also be assumed that the measuring element 34 is part of, or the same as, the transmission elements 42, 44 (especially the second transmission element 44).

[0066] The rotation angle sensor 30 is connected to the control unit 14 via the sensor unit 32 for signal transmission.

[0067] The control unit 14 includes a storage unit 48 in which the absolute value of the webbing length is stored when the webbing spool 28 is withdrawn to adjust the webbing spool 28 from the phantom position to the fully withdrawn position. This value is referred to below as the nominal value.

[0068] In addition, storage unit 48 stores the value of the webbing length when the webbing reel 28 is pulled out to adjust the webbing reel 28 from the minimum position to the phantom position. This value is referred to below as the minimum value.

[0069] The maximum length of webbing that can be pulled out, that is, the length of webbing that can be pulled out from the tape reel 28 to adjust the tape reel 28 from the minimum position to the fully pulled-out position, therefore corresponds to the sum of the minimum value and the nominal value.

[0070] Control unit 14 is configured to perform the following method for determining the current pull-out length of webbing 18.

[0071] In order to determine the current amount of webbing pulled out, i.e. the current length of webbing 18 pulled out, the buckle sensor 26 is used in one step to determine the buckle status.

[0072] In addition, in another step, the absolute rotation angle α of the second transmission element 44 is determined by the rotation angle sensor 30.

[0073] For example, the angular position of the second transmission element 44 in the fully extended position with the reel 18 is used as a reference position for determining the absolute rotation angle α, because this position is always the same regardless of external factors such as seat position.

[0074] If the tongue 24 is inserted into the buckle 22 and the buckle 22 is thus closed, the current absolute webbing pull-out corresponds to the sum of the minimum and nominal values ​​of the components corresponding to the measured absolute rotation angle α.

[0075] Since the rotation of the tape reel 28 is reduced to a rotation angle α of 350° of the second drive element 44 when the tape reel 28 is adjusted from the phantom position to the fully withdrawn position, the withdrawal length of the webbing 18 in this range is also reduced to a rotation angle α of 350° of the second drive element 44.

[0076] Furthermore, the mapping is linear, so the change in the amount of webbing pulled out over the entire range, from the phantom position to the fully pulled-out position, will result in a corresponding change in the rotation angle α. For example, if the nominal value is 700 mm, then in this embodiment the amount of webbing pulled out changes by 700 mm for every 350°, or 2 mm for every 1°.

[0077] For example, if the minimum value is 500mm and the calculated absolute rotation angle α is 120°, then in this embodiment the current absolute webbing pull-out amount is 740mm (=500mm+120°×2mm / °).

[0078] If the tongue 24 is not inserted into the buckle 22, the length of the webbing 18 pulled out can only be determined relative to the buckle 22.

[0079] Here, the current absolute webbing pull-out amount can be approximated as equal to the nominal value's component corresponding to the measured absolute rotation angle α. This means that, unlike when buckle 22 is closed, the minimum value is not added to the nominal value's component in order to calculate the webbing pull-out amount when buckle 22 is open.

[0080] For example, the seat belt system 10 has a height adjuster 50 (see...) Figure 1 The position of the seat, the seat position of the seat height adjuster 52 of the seat 12, and the adjustment path can be used as further information to more accurately determine the webbing pull-out length. For the purposes of this current availability, this information serves as an additional input variable for determining the webbing pull-out length and, in this case, helps to improve the measurement accuracy of the webbing pull-out amount.

[0081] As described above, the lowered design of the transmission mechanism 36 ensures that when the belt reel 28 is adjusted from the phantom position to the fully extended position, the rotation of the belt reel 28 is always reduced to a maximum of 1.0 turn of the measuring element 34 when the buckle 22 is closed. This ensures that the nominal value is always mapped to a maximum of one turn of the measuring element 34, regardless of other factors affecting the extension length of the webbing 18 within this range, such as the position of the belt height adjuster 50, the seat position of the seat height adjuster 52, and the adjustment path.

[0082] In cases where the seat and / or seatbelt are adjustable, it is also advantageous to store the corresponding minimum and / or nominal values ​​for each seat and / or seatbelt position in the storage unit 48, which are used to determine the current webbing pull-out amount in order to improve the accuracy of the determined pull-out length of the webbing 18.

[0083] Using the above method and seat belt system 10, the current absolute webbing pull-out length can be determined very accurately and continuously with minimal equipment technology costs, especially in the range between the fully pulled-out position and the phantom position.

[0084] One reason is that a smaller reduction ratio and a smaller change in tooth surface are required compared to a system that reduces the total number of belt turns from the minimum position to the fully withdrawn position to one turn of the measuring element 34 and measures it.

[0085] In conjunction with the buckle status, an absolute webbing pull-out signal is generated even after an undefined state (e.g., after a power outage). In this way, the absolute pull-out length of the webbing 18 can be reliably determined at any time within the range between the fully pulled-out position and the phantom position. The seatbelt system 10 is therefore a "True Power On" system.

[0086] Furthermore, the existing seat belt system can be extended to the aforementioned seat belt system 10 with minimal cost, as only a few additional components are required when using the existing transmission mechanism.

[0087] Another advantage of the simple structure of the seat belt system 10 is that it can be manufactured at a particularly low cost and can be designed to be particularly space-saving.

[0088] This invention is not limited to the embodiments shown. In particular, the features of one embodiment can be arbitrarily combined with features of other embodiments, especially independent of other features of the corresponding embodiment.

Claims

1. A seat belt system having a control unit (14) and a seat belt (16), the seat belt having a webbing (18) and a belt retractor (20), the seat belt system (10) having a buckle (22) and a tongue (24) for the buckle (22) engaging with the webbing (18). in, The tape retractor (20) has: a tape reel (28) for the webbing (18); a rotation angle sensor (30) having a sensor unit (32) and a rotatable measuring element (34); and a transmission mechanism (36) for connecting the tape reel (28) to the measuring element (34), having at least one transmission element (42, 44). Among them, the scroll (28) has a fully withdrawn position and a phantom position. The characteristic feature is that the transmission mechanism (36) is designed such that when the tape reel (28) is adjusted from the phantom position to the fully withdrawn position, the transmission mechanism (36) reduces the rotation of the tape reel (28) to a maximum of 1.0 turn of the measuring element (34). Each angular position of the measuring element in the range between the phantom position and the fully withdrawn position is uniquely equipped with a tape withdrawal length. When the tape reel (28) is adjusted from the phantom position to the fully withdrawn position, the transmission mechanism (36) reduces the rotation of the tape reel (28) to a greater than 0.9 turn of the measuring element (34). The buckle (22) has a buckle sensor configured to determine whether the buckle is closed. A closed buckle means that the tape withdrawal amount is within the range between the phantom position and the fully withdrawn position. The buckle closure information is also used to determine the withdrawal length to ensure that the tape withdrawal amount is within the range between the phantom position and the fully withdrawn position.

2. The seatbelt system according to claim 1, characterized in that, The transmission element (42, 44) is the measuring element (34) or the measuring element (34) is fixed on the transmission element (42, 44).

3. The seatbelt system according to claim 1 or 2, characterized in that, The tape reel (28) has a minimum withdrawn position, and the transmission mechanism (36) is designed such that when the tape reel (28) is adjusted from the minimum withdrawn position to the fully withdrawn position, the transmission mechanism (36) reduces the rotation of the tape reel (28) to more than 1.0 turns and less than 2.0 turns of the measuring element (34).

4. The seatbelt system according to claim 3, characterized in that, When the tape reel (28) is adjusted from the minimum withdrawn position to the fully withdrawn position, the transmission mechanism (36) reduces the rotation of the tape reel (28) to more than 1.05 turns of the measuring element (34).

5. The seatbelt system according to claim 3, characterized in that, When the tape reel (28) is adjusted from the minimum withdrawn position to the fully withdrawn position, the transmission mechanism (36) reduces the rotation of the tape reel (28) to less than 1.5 turns of the measuring element (34).

6. The seatbelt system according to claim 1 or 2, characterized in that, The rotation angle sensor (30) is a sensing-based sensor.

7. The seatbelt system according to claim 1 or 2, characterized in that, The rotation angle sensor (30) is a magnetic sensor and / or an optical sensor.

8. The seatbelt system according to claim 1 or 2, characterized in that, The transmission mechanism (36) is a single-stage or multi-stage transmission mechanism.

9. The seatbelt system according to claim 1, characterized in that, The seat belt system is configured for the vehicle seat (12).

10. The seatbelt system according to claim 1, characterized in that, When the tape reel (28) is adjusted from the phantom position to the fully withdrawn position, the transmission mechanism (36) reduces the rotation of the tape reel (28) to more than 0.95 turns of the measuring element (34).

11. The seatbelt system according to claim 4, characterized in that, When the tape reel (28) is adjusted from the minimum withdrawn position to the fully withdrawn position, the transmission mechanism (36) reduces the rotation of the tape reel (28) to more than 1.10 revolutions of the measuring element (34).

12. A method for determining the pull-out length of the webbing (18) of the seat belt system (10) wound on a rotatable belt reel (28) in a seat belt system according to any one of claims 1 to 11, wherein, The tape reel (28) has a fully extended position and a phantom position. Within the range between the phantom and fully extended positions, each angular position of the measuring element is uniquely configured with a tape extension length. a) Check whether the latch (24) of the seat belt system (10) is inserted into the buckle (22) of the seat belt system (10). b) When the latch (24) is inserted into the buckle (22), the angular position (a) of the measuring element (34) connected to the belt reel (28) via the transmission mechanism (36) is measured, wherein when the belt reel (28) is adjusted from the phantom position to the fully withdrawn position, the transmission mechanism (36) reduces the rotation of the belt reel (28) to a maximum of 1.0 turn of the measuring element (34), wherein when the belt reel (28) is adjusted from the phantom position to the fully withdrawn position, the rotation of the belt reel (28) is reduced to more than 0.9 turns of the measuring element (34), and c) Determine the pull-out length of the webbing (18) based on the measured angular position (a).

13. The method according to claim 12, characterized in that, When the tape reel (28) is adjusted from the phantom position to the fully withdrawn position, the rotation of the tape reel (28) is reduced to more than 0.95 turns of the measuring element (34).

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