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

Abstract

The invention relates to a restraint device (4) for an occupant sitting on a vehicle seat (1) of a motor vehicle, with - a belt retractor (6) with - a frame which is fastenable in a manner fixed on the vehicle and - a belt shaft rotatably mounted in the frame, and - a safety belt (5), an end of which can be wound onto the belt shaft and which is directed over the shoulder of the occupant in order to restrain the occupant, wherein - a rotary angle sensor (16), which detects the rotational movement of the belt shaft, is provided, and - a position sensor (15) is provided which generates a signal representing the directing angle of the safety belt (5) over the shoulder of the occupant.

Description

[0001] Restraint device for an occupant sitting on a vehicle seat of a motor vehicle, vehicle seat with a restraint device and restraint system

[0002] The present invention relates to a restraint device for an occupant sitting on a vehicle seat of a motor vehicle, having the features of the preamble of claim 1, a vehicle seat having the features of the preamble of claim 3 and a restraint system having the features of the preamble of claim 7.

[0003] Three-point belts have proven particularly effective as restraint devices for occupants sitting on vehicle seats in motor vehicles. These belts comprise a safety belt as their basic element, one end of which can be wound onto a belt shaft of a belt retractor permanently attached to one side of the vehicle seat, and the other end of which is permanently attached to the vehicle via an end fitting on the same side of the vehicle seat. Furthermore, a movable belt tongue is provided on the safety belt, which can be locked in a belt buckle permanently attached to the other side of the vehicle seat to divide the safety belt into a diagonal belt section crossing the occupant's chest and a lap belt section crossing the occupant's pelvis.The belt shaft, on which the safety belt can be wound, is rotatably mounted in a frame of the belt retractor and has a blocking device which is activated as a function of 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 in order to restrain the occupant.

[0004] Furthermore, modern restraint systems can additionally be equipped with reversible and / or irreversible belt tensioners and / or controllable or non-controllable force limiting devices, through which the restraint characteristics of the restraint system can be further optimized, particularly with regard to minimizing occupant load. One problem with such restraint systems is that the restraint of the occupant requires that the occupant has actually fastened their seat belt. Since the applied restraint system generally also results in at least a slight restriction of the occupant's freedom of movement, there are occupants, such as professional drivers, who refuse to put on the restraint system on principle. Furthermore, there is the fundamental problem that occupants sometimes forget to put on the restraint system.

[0005] To remind the occupant to fasten their restraints, seat belt warning devices have proven effective. These emit an audible warning tone when the occupant has not fastened their restraints. This audible warning tone can become more intense over time, so that even the reluctant occupant eventually fastens the restraints to turn off the warning tone. In addition to occupant detection, the seat belt warning system includes a belt buckle sensor, for example, which detects the inserted state of the belt tongue.

[0006] It has been found that particularly reluctant occupants feign a false wearing of their seat belt by inserting a single tongue into the buckle that is not connected to a seat belt. There are also occupants who pull out the seat belt, lock the tongue into the buckle, and then sit on the seat belt.

[0007] Inflatable airbags have also proven effective for restraining occupants. These airbags are attached to the vehicle structure and inflate in the event of an accident, protecting the occupant from impact with the vehicle's internal structure. To optimize the restraint function of the airbags, they can be inflated to a specific occupant-specific geometry using tensioning straps, tear-off seams, or controllable gas generators. This requires detecting the occupant type; it is sufficient to roughly classify the occupant type by height and / or abdominal circumference. Such occupant detection and classification can also be used to control the controllable force limiting device or the controllable pretensioning device.Against this background, the object of the invention is to provide a restraint device, a vehicle seat and a restraint system which enable improved detection of improper use of the restraint device and occupant detection.

[0008] To achieve this object, a restraint device having the features of claim 1 and a vehicle seat having the features of claim 3 and a restraint system having the features of claim 7 are proposed. Further preferred developments of the invention can be found in the subclaims, the figures and the associated description.

[0009] According to the basic idea of ​​the invention, it is proposed that a rotation angle sensor is provided which detects the rotational movement of the belt shaft, and a position sensor is provided which generates a signal representing the feed angle of the safety belt over the shoulder of the occupant.

[0010] The proposed restraint system enables easy detection of a false seat belt fastening or a seat belt not being fastened. First, the rotation angle sensor detects a rotational movement of the belt shaft, and thus a withdrawal movement of the seat belt itself. If the seat belt has not been pulled out and fastened, this can be easily detected using the signal from the rotation angle sensor, thus eliminating the previously required belt buckle sensor. Subsequently, the seat belt's application angle on the occupant is detected using the position sensor. If the application angle lies outside a defined application angle range for a proper seat belt fastening, a conclusion can be drawn immediately that the seat belt is falsely fastened.This can be used, for example, to detect a false fastening condition when the occupant has sat down on the seat belt and the seat belt is positioned between the backrest and the occupant's back. Furthermore, the number of revolutions of the belt shaft and the rotation angle of the belt shaft detected by the rotation angle sensor can be used to determine the seat belt's extended length and thus the occupant's physical proportions, such as height, chest circumference, and chest width.

[0011] It is further proposed that a deflection device be provided at which the seat belt is deflected toward the occupant, and that the position sensor detects the position and orientation of the seat belt after it has been deflected toward the occupant. The deflection device deflects the seat belt toward the occupant, so that the belt retractor itself can be arranged at a location convenient for installation. The seat belt then extends from the belt retractor to the deflection device, regardless of the belt being fastened and the occupant sitting in the vehicle seat, and is only deflected toward 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 to the occupant, so that a direct conclusion can be drawn as to whether the occupant has fastened his or her seat belt or not.

[0012] Furthermore, to achieve the object, a vehicle seat with a restraint device according to one of claims 1 or 2 is proposed, in which the belt retractor is fastened in a backrest of the vehicle seat. Due to the arrangement of the belt retractor in the backrest, the vehicle seat with the belt retractor provides a restraint for the occupant sitting thereon via the safety belt pulled 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 autonomously driving vehicles, in which the vehicle seats can be adjusted over considerably larger adjustment ranges and, in particular, can be rotated.

[0013] In a vehicle seat according to claim 3 with a restraint device according to claim 2, the deflection device is preferably arranged in an upper edge section of the backrest, so that the safety belt runs from above over the occupant's shoulder as it is guided to the occupant. It is further proposed that the position sensor in the vehicle seat detects a distance between the safety belt and the backrest. The distance between the safety belt and the backrest is a very easy-to-detect parameter and, taking into account the position of the position sensor, enables a very simple determination of the course of the safety belt as it is guided to the occupant.

[0014] It is further proposed that the position sensor detect 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 seat belt over the position sensor. This makes it possible to detect a seat belt orientation directed toward the seat surface or away from the vehicle seat.

[0015] Furthermore, to achieve the object, a restraint system comprising a restraint device according to one of claims 1 or 2, or a vehicle seat according to one of claims 3 to 6, is proposed, in which an evaluation device is provided in which a control signal is generated from the signals of the rotation angle sensor and the position sensor. In the evaluation device, the signals of the rotation angle sensor and the position sensor are combined, which in turn enables a more precise conclusion to be drawn about the fastening state and the fastening geometry of the seat belt.

[0016] It is further proposed that a controllable airbag device and / or a controllable force-limiting device and / or a controllable tensioning device be provided in the restraint system, and that the airbag device and / or the force-limiting device and / or the tensioning device be controlled as a function of the control signal. The proposed further development is advantageous in that the restraint of the occupant can be achieved individually for each occupant, and in particular as a function of the belt fastening state and the belt fastening geometry, through the proposed control of the airbag device, force-limiting device and / or tensioning device.

[0017] It is further proposed that an acoustic and / or visual warning device be provided, and that the visual and / or acoustic warning device be activated depending on the control signal. The acoustic and / or visual warning device can alert the occupant to a faulty and / or unfastened seat belt.

[0018] The invention will be explained below using preferred embodiments with reference to the attached figures.

[0019] Fig. 1 shows 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

[0020] Fig. 2 a frontal view of the vehicle seat and the restraint device of Fig.l, and

[0021] Fig. 3 is a side view of the vehicle seat and restraint device of Fig. 1 with a steering wheel and an airbag device.

[0022] Figures 1 and 2 show a vehicle seat 1 according to the invention, comprising a seat surface 3, a backrest 2, and a headrest 9. Furthermore, a restraint device 4 is provided on the vehicle seat 1, comprising a belt retractor 6, a safety belt 5, a deflection device 18, a belt buckle 7 fastened to the vehicle seat 1, a belt tongue (not shown) slidably guided on the safety belt 5, and an end fitting (likewise not shown) fastened to the vehicle seat 1. The belt buckle 7, the end fitting, and the belt retractor 6 can also be fastened to the external vehicle structure if fastening to the vehicle seat is not possible, or if the vehicle seat is only displaceable or movable to the extent that the occupant sitting thereon is safely restrained in all possible positions of the vehicle seat 1 and in all accident scenarios.

[0023] The belt retractor 6 comprises a belt shaft (not shown) which is rotatably mounted in a frame (also not shown) which is fixed to the vehicle. The upper end of the seat belt 5 is held on the belt shaft, which is spring-loaded in the winding direction relative to the frame, so that the seat belt 5 is automatically wound up at this end and, when pulled out, is pulled out against the spring force. The belt retractor 6 and the end fitting (not shown) are fastened to the same side of the vehicle seat 1, while the belt buckle 7 is fastened to the opposite side of the vehicle seat 1. To fasten the seat belt 5, the occupant pulls out the seat belt 5 and locks the belt tongue in the belt 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.

[0024] Furthermore, the restraint device 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 assigned to the belt shaft of the belt retractor 6. The restraint device 4 in the vehicle seat 1 is part of a restraint system which can be seen in Figure 3 and 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 which is also assigned to the belt shaft.

[0025] However, both the controllable force limiting device 12 and the controllable tensioning device 13 and the controllable airbag device 14 can also be arranged differently. Thus, the controllable force limiting device 12 and the controllable tensioning device can also be assigned to the 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.

[0026] The rotation angle sensor 16 is arranged in such a way that it generates a signal dependent on the rotational movement of the belt shaft, from which the pull-off length of the safety belt 5 from the belt shaft can also be directly determined by counting the revolutions and the rotation angle of the belt shaft. The position sensor 15 is arranged in the backrest 2 below the deflection device 18 and is aligned with its sensor field in such a way that when the safety belt 5 pivots about a pivot axis 21 aligned orthogonally to the backrest 2, it generates a changing signal due to the changing overlap, which allows a conclusion to be drawn about the orientation of the safety belt 5. The change in the signal enables, in particular, detection of the orientation of the safety belt 5 in the direction towards the outside O, towards the inside I, upwards U and downwards D, as can be seen in the enlarged illustration in Figure 1.Furthermore, the position sensor 15 is additionally designed such that it also generates a changing signal when the distance A of the safety belt 5 to the position sensor 15 shown in Figure 3 changes.

[0027] The advantage of the restraint device 4 according to the invention is that a false fastening state or even an unfastened seat belt 5 can be detected very easily and reliably by first detecting the extension 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 belt buckle sensor is thus no longer required and therefore cannot be circumvented by inserting a simple belt tongue without a seat belt.

[0028] In this case, a false fastening 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 the orientation and arrangement of the safety belt 5 defined for a proper fastening state.

[0029] Furthermore, the restraint device 4 according to the invention can be used to carry out a very simple occupant classification, by means of which an occupant-specific control of the restraint of the occupant 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.

[0030] For example, a tall occupant can be detected by detecting an extended length of the seat belt 5 that is greater than a defined value, and the position sensor 15 detecting a larger distance A, i.e., a larger angle, of the seat belt 5 compared to a predetermined distance A or angle with respect to the backrest 2. Furthermore, conversely, a short occupant can be detected if the extended length of the seat belt 5 and the distance A are smaller than a predetermined value.

[0031] In the same way, a corpulent occupant with a large chest circumference can be distinguished from a slender occupant with a small chest circumference.

[0032] The position sensor 15 is arranged in the backrest 2 below the deflection device 18, and its sensor field is directed toward 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 rests against it. Since the arrangement and orientation of the diagonal belt section 10 are particularly representative of the seat belt fastening status and the occupant's physical proportions, this enables particularly accurate and reliable detection of the seat belt fastening status and the occupant's physical proportions.The body proportions, in turn, are decisive for the occupant's weight and geometry, which in turn are crucial for the occupant's restraint. Occupant restraint can be individually improved through appropriate occupant-specific control of the airbag device 14, the force limiting device 12, and the tensioning device 13. Occupant detection and detection of the seat belt fastening status are made possible solely by the use of two sensors, namely the rotation angle sensor 16 and the position sensor 15. The slight additional costs are offset by the elimination of the previously provided belt buckle sensor.

[0033] Furthermore, the restraint system additionally comprises 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 fastened or not fastened safety belt 5.

Claims

Claims:

1. Restraint device (4) for an occupant sitting on a vehicle seat (1) of a motor vehicle, comprising -a belt retractor (6) with -a frame that can be fixed to the vehicle and -a belt shaft rotatably mounted in the frame, and -a safety belt (5) which can be wound onto the belt shaft at one end and which is guided over the shoulder of the occupant to restrain the occupant, characterized in that -a rotation angle sensor (16) is provided which detects the rotational movement of the belt shaft, and -a position sensor (15) is provided which generates a signal representing the feed angle of the safety belt (5) over the shoulder of the occupant.

2. Restraint device (4) according to claim 1, characterized in that -a deflection device (18) is provided, at which the safety belt (5) is deflected towards the occupant, and -the position sensor (15) detects the position and orientation of the safety belt (5) after it has been deflected towards the occupant.

3. Vehicle seat (1) with a restraint device (4) according to one of claims 1 or 2, characterized in that -the belt retractor (6) is fastened in a backrest (2) of the vehicle seat (1).

4. Vehicle seat (1) according to claim 3 with a restraint device (4) according to claim 2, characterized in that -the deflection device (18) is arranged in an upper edge section (8) of the backrest (2).

5. Vehicle seat (1) according to one of claims 3 or 4, characterized in that - the position sensor (15) detects a distance (A) of the safety belt (5) to the backrest (2).

6. Vehicle seat (1) according to one of claims 3 to 5, characterized in 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).

7. Restraint system with a restraint device (4) according to one of claims 1 or 2, or with a vehicle seat according to one of claims 3 to 6, characterized in that -an evaluation device (17) is provided in which a control signal is generated from the signals of the rotation angle sensor (16) and the position sensor (15) 8. Restraint system according to claim 7, characterized in that -a controllable airbag device (14) and / or a controllable force-limiting device (12) and / or a controllable tensioning device (13) is provided, and -the airbag device (14) and / or the force-limiting device (12) and / or the tensioning device (13) is controlled in dependence on the control signal.

9. Restraint system according to claim 7 or 8, characterized in that -an acoustic and / or optical warning device (20) is provided, and -the optical and / or acoustic warning device (20) is activated in dependence on the control signal.

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