Restraint system with a restraint device for an occupant sitting on a vehicle seat of a motor vehicle and vehicle seat with a restraint system

Abstract

Restraint system with a restraint device (4) for an occupant seated on a vehicle seat (1) of a motor vehicle with -a belt retractor (6) with -a frame that can be securely attached to the vehicle and -a belt shaft rotatably mounted in the frame, and -a safety belt (5) which can be wound up at one end on the belt shaft and which is supplied over the occupant's shoulder to restrain the occupant, characterized in that -a rotation angle sensor (16) detecting the rotational movement of the belt shaft is provided, and -a position sensor (15) is provided which generates a signal representing the angle of the seat belt (5) over the occupant's shoulder, and -an evaluation device (17) is provided in which a control signal is generated from the signals of the rotary angle sensor (16) and the position sensor (15), and -an acoustic and / or optical warning device (20) is provided, and -the optical and / or acoustic warning device (20) is activated depending on the control signal.

Description

[0001] The present invention relates to a restraint system comprising a restraint device for an occupant seated on a vehicle seat of a motor vehicle, comprising the features of the preamble of claim 1, and a vehicle seat comprising a restraint system comprising the features of the preamble of claim 4.

[0002] Three-point seat belts have proven particularly effective as restraint devices for occupants seated in motor vehicles. These belts consist of a seat belt with one end that can be wound onto a belt shaft of a belt retractor permanently attached to one side of the vehicle seat, and the other end that is permanently attached to the same side of the seat by an end fitting. Furthermore, the seat belt features a sliding tongue that divides the belt into a diagonal section crossing the occupant's chest and a lap section crossing the occupant's pelvis. This tongue can be locked into a buckle permanently attached to the opposite side of the vehicle seat.The belt shaft, onto which the safety belt can be wound, is rotatably mounted in a frame of the belt retractor and has a locking device which is activated depending on the exceeding of a predetermined extension acceleration of the safety belt and / or the exceeding of a predetermined vehicle deceleration and blocks further rotation of the belt shaft in the extension direction of the safety belt to restrain the occupant.

[0003] Furthermore, modern restraint systems can additionally be equipped with reversible and / or irreversible belt tensioners and / or controllable or non-controllable force limiting devices, which can further optimize the restraint characteristics of the restraint system, particularly with regard to minimizing occupant stress.

[0004] One problem with such restraint systems is that restraining the occupant requires that the occupant is actually wearing a seatbelt. Since the restraint system inherently results in at least a slight restriction of the occupant's freedom of movement, some occupants, such as professional drivers, refuse to wear the restraint system altogether. Furthermore, there is the fundamental problem that occupants sometimes forget to put on the restraint system.

[0005] To remind occupants to fasten their restraints, seatbelt warning devices have proven effective. These devices emit an audible warning tone if the occupant is not wearing the restraint. This tone can become more intense over time, eventually prompting even reluctant occupants to fasten their restraints and silence the warning. In addition to occupant detection, the seatbelt warning device includes features such as a seatbelt buckle sensor that detects the buckle's position.

[0006] It has been found that particularly unwilling occupants feign a properly fastened seatbelt by inserting a single belt tongue into the buckle, which is not connected to a seatbelt. Furthermore, there are also occupants who unfasten the seatbelt, lock the belt tongue in the buckle, and then sit down on the seatbelt.

[0007] Furthermore, inflatable airbags have proven effective in restraining occupants. These airbags are attached to the vehicle structure and inflate in the event of an accident, protecting the occupants from impact with the vehicle's interior. To optimize the restraint function of the airbags, they can be inflated to a specific occupant-related geometry using tension straps, tear seams, or controllable gas generators. This requires occupant type detection, for which a rough classification based on height and / or waist circumference is sufficient. Such occupant detection and classification can also be used to control the controllable force limitation device or the controllable pretensioning device.

[0008] From publication DE 10 2015 007 557 A1, a method and a device for determining the extension length of a belt wound on a rotatable belt spool are also known, in which a sensor is provided in the belt buckle which detects the inserted state of a locking tongue therein. Furthermore, a sensor device is provided which detects the angular position of the belt spool.

[0009] From publication US 2017 / 0217402 A1, a method is known in which the position of a deflection device for a seat belt is detected by means of a sensor device for adjustment.

[0010] From the subsequently published document DE 10 2021 125 093 A1, a vehicle seat with an integrated restraint system is known, in which a sensor device is provided on a first belt retractor associated with the backrest. Furthermore, a second sensor device is provided on a belt buckle or belt tongue, which detects the tensile force exerted by the lap belt section or the diagonal belt section.

[0011] Against this background, the invention is based on the objective of providing a restraint system with a restraint device and a vehicle seat with a restraint system, which enable improved detection of improper use of the restraint device and occupant detection.

[0012] To solve the problem, a restraint system with a restraint device having the features of claim 1 and a vehicle seat having the features of claim 4 are provided. Further preferred embodiments of the invention can be found in the dependent claims, the figures and the accompanying description.

[0013] According to the basic idea of ​​the invention, it is proposed that a rotation angle sensor detecting the rotational movement of the belt shaft is provided, and a position sensor is provided which generates a signal representing the angle of the seat belt over the occupant's shoulder, and an evaluation device is provided in which a control signal is generated from the signals of the rotation angle sensor and the position sensor, and an acoustic and / or optical warning device is provided, and the optical and / or acoustic warning device is activated depending on the control signal.

[0014] The proposed restraint system enables the simple detection of a seatbelt being either not fastened or not fastened. First, a rotational movement of the belt shaft, and thus an extension movement of the seatbelt itself, is detected via the rotational angle sensor. If the seatbelt has not been extended and fastened, this can be easily detected by the signal from the rotational angle sensor, eliminating the need for the previously required buckle sensor. Subsequently, the angle at which the seatbelt is positioned on the occupant is detected by the position sensor. If this angle falls outside a defined range for proper restraint, a conclusion can be immediately drawn that the seatbelt is not fastened.This allows, for example, the detection of a false fastening state when the occupant has sat down on the seatbelt and the belt runs between the seatback and the occupant's back. Furthermore, the number of rotations of the belt shaft and the rotation angle of the belt shaft, detected by the rotation angle sensor, allow conclusions to be drawn about the extension length of the seatbelt and thus about the occupant's physical proportions, such as height, chest circumference, and chest width.

[0015] It is further proposed that a deflection device be provided, at which the seat belt is redirected towards the occupant, and that the position sensor detects the position and orientation of the seat belt after this redirection. The deflection device redirects the seat belt towards the occupant, allowing the belt retractor itself to be positioned in a location convenient for installation. The seat belt then extends from the belt retractor to the deflection device, regardless of whether the seat belt is fastened or whether the occupant is seated in the vehicle seat, and is only redirected towards the occupant at the deflection device or, if the occupant is not fastened, into a parked position.The proposed arrangement of the position sensor detects the arrangement and orientation of the seat belt directly in the feed towards the occupant, so that a direct conclusion can be drawn as to whether the occupant has buckled up or not.

[0016] Furthermore, to solve the problem, a vehicle seat with a restraint system according to one of claims 1 to 3 is proposed, in which the belt retractor is attached to a backrest of the vehicle seat. Due to the arrangement of the belt retractor in the backrest, the vehicle seat, together with the belt retractor, provides restraint for the occupant seated therein via the seat belt tensioned by the belt retractor, which is independent of the position, arrangement, and orientation of the vehicle seat in the vehicle. This is particularly advantageous in autonomous vehicles, where the vehicle seats are adjustable over considerably larger ranges and, in particular, are rotatable.

[0017] In this case, the deflection device in a vehicle seat according to claim 3 with a restraint system according to one of claims 2 or 3 in reference to claim 2 is preferably arranged in an upper edge section of the backrest, so that the safety belt runs from above over the occupant's shoulder in the feed to the occupant.

[0018] It was further proposed that the position sensor in the vehicle seat detect the distance between the seat belt and the backrest. This distance is a very easy-to-detect parameter and, taking into account the position of the sensor, allows for a very simple determination of the seat belt's path as it leads to the occupant.

[0019] It is further proposed that the position sensor detects the angle of the seat belt relative to a pivot axis running orthogonally to the backrest. This can be achieved, for example, by detecting the overlap of the position sensor with the seat belt. This makes it possible to detect whether the seat belt is oriented towards or away from the vehicle seat.

[0020] The invention is explained below with reference to preferred embodiments and the accompanying figures. Fig. 1 a vehicle seat according to the invention with a restraint device according to the invention in an oblique view and an enlarged section thereof, and Fig. 2 a frontal arrangement of the vehicle seat and the restraint system of the Fig. 1, and Fig. 3 a side view of the vehicle seat and restraint system of the Fig. 1 with a steering wheel and an airbag system.

[0021] In the Fig. 1 and Fig. Figure 2 shows a vehicle seat 1 according to the invention, comprising a seat surface 3, a backrest 2, and a headrest 9. Furthermore, the vehicle seat 1 is equipped with a restraint device 4, comprising a belt retractor 6, a seat belt 5, a deflection device 18, a belt buckle 7 attached to the vehicle seat 1, a belt tongue (not shown) slidably guided on the seat belt 5, and an end fitting (also not shown) attached to the vehicle seat 1. The belt buckle 7, the end fitting, and the belt retractor 6 can also be attached to the external vehicle structure if attachment to the vehicle seat is not possible, or if the vehicle seat is only slidable or movable to the extent that the occupant seated on it is safely restrained in all possible positions of the vehicle seat 1 and in all accident scenarios.

[0022] The belt retractor 6 comprises a belt shaft (not shown) which is rotatably mounted in a frame (also not shown) that is fixed to the vehicle. The seat belt 5 is held at its upper end by the belt shaft, which is spring-loaded relative to the frame in the winding direction, so that the seat belt 5 is automatically wound up at this end and, when extended, is pulled out against the spring force. The belt retractor 6 and the end fitting (not shown) are attached to the same side of the vehicle seat 1, while the belt buckle 7 is attached to the opposite side of the vehicle seat 1. To fasten the seat belt 5, the occupant pulls the seat belt 5 out and locks the belt tongue in the buckle, resulting in the proven 3-point geometry of the seat belt 5 with the diagonal belt section 10 crossing the occupant's chest and the lap belt section 11 crossing the pelvis.

[0023] Furthermore, the restraint system 4 comprises a position sensor 15 arranged in an upper edge section 8 of the backrest 2 below the deflection device 18 and a rotation angle sensor 16 associated with the belt shaft of the belt retractor 6. The restraint system 4 in the vehicle seat 1 is part of a system in the Fig. 3 recognizable restraint system, which further comprises an evaluation device 17, a controllable airbag device 14 arranged in a steering wheel 19, a controllable force limiting device 12 assigned to the belt shaft of the belt retractor 6 and a controllable tensioning device 13 also assigned to the belt shaft.

[0024] However, the controllable force limiting device 12, the controllable tensioning device 13, and the controllable airbag device 14 can also be arranged differently. For example, the controllable force limiting device 12 and the controllable tensioning device can also be assigned to the seat belt buckle 7, the end fitting, or the deflection device 18. Furthermore, the controllable airbag device 14 can also be arranged in an instrument panel, in a roof structure, in a side structure, or in the footwell of the vehicle.

[0025] The rotation angle sensor 16 is arranged to generate a signal dependent on the rotational movement of the belt shaft. From this signal, the pull-off length of the seat belt 5 from the belt shaft can be directly determined by counting the revolutions and the rotation angle of the belt shaft. The position sensor 15 is located in the backrest 2 below the deflection device 18 and its sensor field is oriented such that when the seat belt 5 pivots about a pivot axis 21 orthogonal to the backrest 2, the changing overlap generates a changing signal that allows conclusions to be drawn about the orientation of the seat belt 5. In particular, the signal change enables the detection of the orientation of the seat belt 5 in the direction of the outside (O), the inside (I), upwards (U), and downwards (D), as shown in the enlarged illustration. Fig. 1 can be seen. Furthermore, the position sensor 15 is additionally designed to also generate a changing signal when the object in the Fig. 3. Distance A of the safety belt 5 to the position sensor 15 shown has changed.

[0026] The advantage of the restraint device 4 according to the invention lies in the fact that a false fastening state or an unfastened seat belt 5 can be detected very easily and reliably by first detecting the unfastening of the seat belt 5 via the signal from the rotation angle sensor 16 and then detecting the position and orientation of the seat belt 5 via the position sensor 15. A buckle sensor is therefore no longer required and cannot be circumvented by simply inserting a belt tongue without a seat belt.

[0027] A false fit state of the safety belt 5 can be detected in particular by the position sensor 15 detecting an orientation and arrangement of the safety belt 5 which lies outside a range of orientation and arrangement of the safety belt 5 defined for a proper fit state.

[0028] Furthermore, the restraint device 4 according to the invention enables a very simple occupant classification, by means of which occupant-specific control of the occupant restraint can be carried out in a restraint system according to the invention with a controllable airbag device 14, a controllable force limiting device 12 and / or a controllable tensioning device.

[0029] For example, a tall occupant can be detected by the seat belt 5 being extended beyond a defined value, and the position sensor 15 detecting a greater distance A, i.e., a greater angle of the seat belt 5, compared to a predetermined distance A or angle relative to the backrest 2. Conversely, a short occupant can be detected if the seat belt 5's extension and the distance A are both less than a predetermined value.

[0030] Similarly, a corpulent inmate with a large chest circumference can be distinguished from a slim inmate with a small chest circumference.

[0031] The position sensor 15 is located in the backrest 2 below the deflection device 18 and its sensor field is directed towards the upper side of the seat belt 5 facing the backrest 2. This detects the orientation of the seat belt 5 in the area of ​​the diagonal belt section 10 extending from the deflection device 18, which is crucial for restraining the occupant's upper body and restrains it. Since the arrangement and orientation of the diagonal belt section 10 are particularly representative of the occupant's restraint status and body proportions, this enables a particularly accurate and reliable detection of the restraint status and body proportions.The occupant's physical proportions are crucial for their weight and geometry, which in turn are decisive for their restraint. Therefore, by appropriately controlling the airbag system 14, the force limiting device 12, and the tensioning device 13 in a way that is specific to each occupant, their restraint can be individually improved. Occupant detection and seatbelt fastening detection are achieved solely through the use of two sensors: the rotation angle sensor 16 and the position sensor 15. The slightly higher costs are offset by the elimination of the previously required seatbelt buckle sensor.

[0032] Furthermore, the restraint system additionally includes a controllable acoustic and / or optical warning device 20, which is activated by means of a signal generated by the evaluation unit 17, which in turn is generated from the signals of the rotation angle sensor 16 and / or the position sensor 15, and alerts the occupant to an incorrectly or not fastened seat belt 5.

Claims

[1] Restraint system comprising a restraint device (4) for an occupant seated on a vehicle seat (1) of a motor vehicle with -a belt retractor (6) with -a frame that can be securely attached to the vehicle and -a belt shaft rotatably mounted in the frame, and -a safety belt (5) which can be wound up with one end on the belt shaft and which is fed over the occupant's shoulder to restrain the occupant, characterized by , that -a rotation angle sensor (16) detecting the rotational movement of the belt shaft is provided, and -a position sensor (15) is provided which generates a signal representing the angle of the seat belt (5) over the occupant's shoulder, and -an evaluation device (17) is provided in which a control signal is generated from the signals of the rotary angle sensor (16) and the position sensor (15), and -an acoustic and / or optical warning device (20) is provided, and -the optical and / or acoustic warning device (20) is activated depending on the control signal. [2] Restraint system according to claim 1, characterized by , that -a deflection device (18) is provided, by which the safety belt (5) is deflected towards the occupant, and -The position sensor (15) detects the position and orientation of the seat belt (5) after it is deflected towards the occupant. [3] Restraint system according to one of claims 1 or 2, characterized by , that -a controllable airbag device (14) and / or a controllable force limiting device (12) and / or a controllable penalizing device (13) is provided, and -the airbag device (14) and / or the force limiting device (12) and / or the tensioning device (13) is controlled depending on the control signal. [4] Vehicle seat (1) with a restraint system (4) according to one of claims 1 to 3, characterized by , that -the belt retractor (6) is attached to a backrest (2) of the vehicle seat (1). [5] Vehicle seat (1) according to claim 4 with a restraint system according to one of claims 2 or 3 in reference to claim 2, characterized by , that -the deflection device (18) is arranged in an upper edge section (8) of the backrest (2). [6] Vehicle seat (1) according to one of claims 4 or 5, characterized by , that -the position sensor (15) detects a distance (A) of the seat belt (5) to the backrest (2). [7] Vehicle seat (1) according to any one of claims 4 to 6, characterized by , that -the position sensor (15) detects the angle (W) of the safety belt (5) in relation to a pivot axis running orthogonally to the backrest (2).

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