METHOD FOR CONTROLLING AT LEAST ONE COMPONENT OF AN OCCUPANT RESTRICTION DEVICE FOR A MOTOR VEHICLE

Description

[0001] The invention relates to a method for controlling at least one component of an occupant restraint device for a motor vehicle with the features of the preamble of claim 1. The invention further relates to an occupant restraint device for carrying out the method and a motor vehicle with at least one such occupant restraint device.

[0002] In motor vehicles, occupant restraint systems consisting of airbags and seat belts are used to couple an occupant to the vehicle's deceleration in the event of a crash and prevent body parts (such as the head) from striking interior components. Upon detection of an impact (generally via acceleration sensors measuring the vehicle's deceleration), the seat belt tightens and locks, and the corresponding airbag is deployed. Such occupant restraint systems are typically equipped with pyrotechnic actuators to tighten the seat belt and inflate the airbag within milliseconds.

[0003] A method with the features of the preamble of claim 1 is known, for example, from DE 10 2015 201 721 A1. Specifically, the disclosed occupant restraint device comprises a safety belt designed as a three-point belt, which is movably connected to a belt retractor via two deflection elements. Each deflection element is slidably mounted relative to a vehicle-fixed structure and is each provided with a drive unit that can move the respective deflection element. The deflection elements can be controlled via a control unit, the control unit being connected to collision sensors. Each of the deflection elements constitutes a belt tensioning device, whereby belt tensioning can be achieved by vertically moving the deflection elements.

[0004] If the collision sensors detect a collision that has occurred or is imminent, a trigger signal is generated and the seat belt is tightened by a first belt tensioning device. After a predetermined time interval following activation of the first belt tensioning device, a second belt tensioning device tightens the seat belt again. This method is designed to ensure highly effective tensioning of the seat belt even in the event of a secondary collision following the initial collision.

[0005] German patent DE 10 2016 206 533 A1 describes an occupant restraint device which also includes a three-point seat belt. The three-point seat belt can be tightened by a motor-driven belt retractor. The motor of the belt retractor is controlled by a control unit, which is connected to a pre-crash sensor. The control unit also serves to control a displacement mechanism of a lumbar support device in a seat backrest.

[0006] If the pre-crash sensor predicts a rear-end collision and the foremost part of the lumbar support is not in its lowest position, the belt retraction mechanism is activated first. Then, the adjustment mechanism for the lumbar support is activated to move the foremost part of the support to its lowest and forwardmost position. This is intended to reduce the force exerted on the neck of a seated occupant in a rear-end collision as early as possible.

[0007] A safety belt assembly for use in a motor vehicle is known from WO 02 / 062630 A1. The assembly comprises a safety belt, one end of which is connected to a belt extender, and a sensor that generates a signal representative of the unwinding length of the safety belt. A force limiter is connected to the belt extender to allow the safety belt to unwind with a varying force limitation. A control arrangement changes the force level acting on the force limiter depending on the unwinding length of the safety belt from the belt extender.

[0008] From DE 199 56 530 A1, an occupant restraint device and a method for controlling the occupant restraint device are known. The method works as follows: When a vehicle's energy absorption mechanism is activated, a displacement sensor detects the extension length of the seat belt, and an extension speed calculation unit determines the belt extension speed. Based on information from a speed sensor, a road surface is calculated. An occupant acceleration calculation unit calculates the occupant's acceleration relative to the road surface from the calculated belt extension speed and the calculated vehicle speed. Impact forces acting on the occupant can be reduced in a simple and highly accurate manner, regardless of the occupant's weight and regardless of whether the vehicle is equipped with an airbag.

[0009] A restraint system for a vehicle occupant is known from US patent 2001 / 0040065 A1. A rear collision sensor is designed to detect a potential collision with the rear of the vehicle. Upon detection, a control unit activates a seatbelt system such that the occupant's head is restrained towards a headrest or that the occupant's spine is straightened to protect the occupant's neck from the impending collision.

[0010] A motorized seatbelt retractor is known from US patent 2002 / 0024211 A1. The motorized seatbelt retractor is designed to respond to a signal indicating a dangerous condition of the vehicle. In response to the signal, the retractor pulls in a section of the seatbelt before a collision, thereby pulling a vehicle occupant back into their seat. The retractor is activated each time a dangerous condition is detected.

[0011] Based on the prior art, the present invention aims to provide a method for controlling at least one component of an occupant restraint device for a motor vehicle, in which maximum safety can be achieved in the event of an impending or actual impact while simultaneously reducing the occupant load.

[0012] Furthermore, the invention is based on the objective of providing a suitable occupant restraint device for carrying out the method.

[0013] The present problems are solved by a method having the features of claim 1 and by an occupant restraint device having the features of claim 12.

[0014] Advantageous developments or further developments of the invention can be found in the respective dependent claims.

[0015] A vehicle speed detector unit measures the vehicle speed relative to the road surface. An occupant acceleration calculation unit calculates the acceleration of an occupant relative to the road surface based on the calculated deployment speed of the seatbelt and the calculated vehicle speed. Impact forces acting on the occupant can be reduced simply and with high accuracy, regardless of the occupant's weight and whether the vehicle is equipped with an airbag.

[0016] A restraint system for a vehicle occupant is known from US patent 2001 / 0040065 A1. A rear collision sensor is designed to detect a potential collision with the rear of the vehicle. Upon detection, a control unit activates a seatbelt system such that the occupant's head is restrained towards a headrest or that the occupant's spine is straightened to protect the occupant's neck from the impending collision.

[0017] A motorized seatbelt retractor is known from US patent 2002 / 0024211 A1. The motorized seatbelt retractor is designed to respond to a signal indicating a dangerous condition of the vehicle. In response to the signal, the retractor pulls in a section of the seatbelt before a collision, thereby pulling a vehicle occupant back into their seat. The retractor is activated each time a dangerous condition is detected.

[0018] From DE 10 2013 214 171 A1, a device for adjusting the slack of a vehicle's seat belt is known. The device comprises a controllable motor, a belt reel coupled to the motor for winding and / or unwinding a seat belt webbing, and a control element configured to impart a first torque to the belt reel to wind up the webbing, in particular at a first speed, or to impart a second torque to unwind the webbing, in particular at a second speed, wherein the second speed is lower than the first speed and / or wherein the second torque is lower than the first torque.

[0019] Based on the prior art, the present invention aims to provide a method for controlling at least one component of an occupant restraint system for a motor vehicle, whereby maximum safety can be achieved in the event of an impending or actual impact while simultaneously reducing the occupant load. Furthermore, the invention aims to provide a suitable occupant restraint system for carrying out the method.

[0020] The present problems are solved by a method having the features of claim 1 and by an occupant restraint device having the features of claim 9.

[0021] Advantageous developments or further developments of the invention can be found in the respective dependent claims.

[0022] The invention relates to a method for controlling at least one component of an occupant restraint device for a motor vehicle. In the method, at least in the event of an impact with an object not belonging to the vehicle, which appears unavoidable, the at least one component is controlled in a process phase such that the occupant restraint device exerts a force on the occupant which is directed against an expected, impact-induced forward displacement of the occupant.

[0023] A component of the occupant restraint system can be, for example, a now common three-point seat belt. In the event of an impending collision, the seat belt is tightened by a belt tensioning mechanism, pulling the buckled-in occupant firmly against the vehicle seat. The seat belt thus exerts a force on the occupant that is directed against the expected forward displacement of the occupant in the event of an impact.

[0024] Since the seatbelt movement device is mostly pyrotechnical, i.e. irreversible, very high forces act on the occupant within a very short time, which cannot be specifically adapted to the occupant.

[0025] The invention therefore proposes that, in one process phase, the at least one component is controlled in such a way that a certain gradient and / or a certain maximum of the force acting on the occupant is not exceeded. In this phase, the control of the at least one component is thus force-controlled. In another, subsequent process phase, the at least one component is controlled in such a way that a forward displacement of the occupant over a certain or determinable distance is permitted. In the subsequent process phase, the component is thus displacement-controlled.

[0026] In this way, the process can be divided into two directions of action, which, regardless of the vehicle occupant's weight, can limit the force exerted on the occupant by the occupant restraint device. This leads to a significant improvement in the protective effect for the occupant.

[0027] According to an initial refinement, it is proposed that at least one component is an electric motor of a seatbelt actuator, which in one process phase is controlled such that the occupant's seatbelt is tightened without exceeding a specific gradient and / or a specific maximum current draw of the electric motor. In the aforementioned other process phase, the electric motor is controlled in the opposite direction. This is done in such a way that the occupant is moved forward, whereby rotation of the electric motor is only permitted up to a specific limit of the distance traveled by the occupant.

[0028] In this way, a significant reduction in the force acting on the occupant is possible in both phases of the process. This can be monitored in a technically simple manner by measuring the current draw of the electric motor on the one hand and the rotation of the electric motor on the other. Monitoring is conceivable, for example, using a current measuring unit on the one hand and a rotation angle sensor on the other, with these components being assigned to and / or directly integrated into the electric motor.

[0029] According to another embodiment of the invention, the limit value for the forward displacement distance is advantageously defined as the maximum available forward displacement distance for the impact in the interior. In this way, a maximum reduction of the impact-induced load on the occupant is possible while providing maximum protection.

[0030] The method can be further improved by defining the specific gradient and / or the maximum current consumption and / or the limit value of the forward displacement distance as a function of the expected impact severity. The expected impact severity can be determined, for example, by the relative velocity to the detected impact object, the estimated mass of the impact object, and / or the existing overlap with the impact object. These parameters are preferably acquired using suitable environmental sensors, such as camera systems and ultrasonic sensors. This allows for a more precise adjustment of the method to the specific load case.

[0031] In another embodiment of the invention, it is proposed that the specific gradient and / or the maximum current consumption and / or the limit value of the forward displacement distance from the occupant also be determined as a function of acquired occupant data. Such occupant data could include, for example, the occupant's position, weight, height, or seatbelt fastening status. Such data can be acquired, for example, by suitable occupant detection, which may include an interior camera, seat occupancy detection, seatbelt locking detection, and weight sensors.

[0032] Another refinement of the method proposes that the forward movement be controlled over its entire path. Here, the necessary forward movement of the occupant is continuously measured by the vehicle's deceleration control system based on measured decelerations, and the required forward movement is provided or released for the occupant via the electric motor of the seatbelt actuator. The forward movement is preferably friction-damped, for example, via a self-locking gearbox. This gearbox can be interposed, for instance, between the electric motor and a rotating shaft of the seatbelt actuator. This allows the forward movement to be precisely metered and released via the rotation of the electric motor.

[0033] This particular procedural phase can also be referred to as the "pre-crash phase." By extending the duration of this phase, seatbelt slack and any existing forward movement of the occupant (so-called OOP = Out Of Position) can be reduced early on. Thus, for a significantly longer duration than usual, and with considerably less power input, the occupant can be coupled to the vehicle, achieving an effect comparable to that of a pyrotechnic seatbelt pretensioner operating for a very short period.

[0034] Due to the use of electric motors to drive the seatbelt tensioning mechanism, and thus its reversible design, the decision to tighten the seatbelt can be reversed at any time without unduly affecting the occupant due to the forces involved. The decision can be reversed, for example, if the vehicle's environmental sensors detect that no impact has occurred.

[0035] Tests have shown that the duration of one process phase, the pre-crash phase, is preferably approximately 4 to 7 times, and particularly preferably approximately 6 times, the duration of the other process phase, the in-crash phase. With this time ratio, which occurs in the millisecond range, the reduced power input allows for a particularly gentle tightening of the seatbelt for the occupant.

[0036] To enable higher performance from the electric motor of the seatbelt actuator even with lower currents and cable cross-sections, it is very advantageous to use a high-voltage source to power the motor. Particularly in electric vehicles, the high-voltage electrical system, i.e., the voltage of the traction battery, can be used.

[0037] According to the invention, the reliable execution of the method is enhanced by the fact that the method operates based on environmental sensor data in one process phase (pre-crash phase) and on acceleration sensor data in the other process phase (in-crash phase). Environmental and acceleration sensor components have a long history of proven reliability and can therefore contribute to the reliability of the method.

[0038] However, to maximize safety, it is advantageous to maintain a certain degree of system redundancy. According to the invention, this is achieved by pyrotechnically triggering at least one further component of the occupant restraint system when the acceleration sensors detect an impact that had not already been identified as unavoidable by the environmental sensors.

[0039] For situations where the environmental sensors detect an impact too late, the inventive design of the method can create a fallback position. In one alternative configuration, the additional component is designed as an end-fitting tensioner that is pyrotechnically ignited. Thus, the electrically actuated belt movement device (electrically actuated belt tensioner) and the pyrotechnic tensioner are located at different points within the belt system. Another alternative configuration provides for their installation at the same location.

[0040] As already mentioned, the invention also relates to an occupant restraint device for carrying out the method according to the invention. Such an occupant restraint device comprises at least one safety belt, a belt movement device, and a belt end fitting with a belt buckle.

[0041] According to the invention, the occupant restraint device is now arranged such that the belt movement device is coupled to at least one electric motor and can be moved in two opposite directions by the electric motor.

[0042] In this way, the two previously described process phases can be implemented using the occupant restraint device.

[0043] To ensure controlled forward movement, particularly during the crash phase, it is highly advantageous for the electric motor to be coupled to the belt drive via a self-locking gearbox. This self-locking gearbox can, for example, be in the form of a worm gear.

[0044] In a further development of the occupant restraint system, the belt end fitting can be moved by a pyrotechnic unit. This provides, as already mentioned, an additional level of safety.

[0045] Finally, the invention is also intended to provide protection for a motor vehicle which has at least one occupant restraint device according to the invention.

[0046] A preferred embodiment of the invention is illustrated in the figures and is explained in more detail in the following description with reference to the figures. This also highlights further advantages of the invention. Identical reference numerals, even in different figures, refer to identical, comparable, or functionally equivalent components. Corresponding or comparable properties and advantages are achieved even if no repeated description or reference is made to them. The figures are not always to scale. In some figures, proportions may be exaggerated to more clearly emphasize features of an embodiment.

[0047] They show, each schematically Fig. 1 shows a motor vehicle with an occupant restraint device which operates according to the method according to the invention; Fig. 2 shows a further simplified representation according to view II. Fig. 1, in a pre-crash phase, Fig. 3 a representation comparable to Fig. 2 , in a crash phase and Fig. 4 shows a time-dependent force profile of the belt force acting on the occupant.

[0048] It will be directed to the Figs. 1 to 3 Reference made to.

[0049] In the Fig. 1 The passenger compartment of a motor vehicle K is shown in the cockpit area. An occupant IN has taken a seat in a driver's seat which has a seat cushion 4, a seat backrest 5 and a headrest 6.

[0050] The occupant IN is secured by an occupant restraint device 1 and is in a normal driving position in front of a steering wheel 3 and an instrument panel 2. The steering wheel 3 is equipped with an implied pyrotechnic airbag device 30.

[0051] The occupant restraint device 1 comprises as components a safety belt 10 designed as a three-point belt. The safety belt 10 is connected via a deflection device 11 to a vehicle-mounted belt movement device 12.

[0052] In the area of ​​the occupant's pelvis IN, the safety belt 10 is connected to a belt end fitting 16.

[0053] The belt movement device 12 has a belt winding device 13 which is rotatable about a pivot axis D in two directions DR.

[0054] The axis of rotation D or shaft of the belt winding device 13 is movably connected to an electric motor 15 via an intermediate, self-locking gearbox 14. The gearbox 14 can be designed as a worm gear.

[0055] The electric motor 15 can be driven in two opposite directions of rotation DR, so that the safety belt 10 can be wound up in one direction R1, i.e. tightened, or unwound in one direction R2 by the belt winding device 13.

[0056] The belt end fitting 16 further comprises a belt buckle 17 into which a belt tongue 18 of the safety belt 10 can be inserted and thus secured. The belt end fitting 16 can preferably also be provided with a pyrotechnic end fitting tensioner 19, by means of which the belt end fitting 16 can be moved downwards in a direction R3 and thus also tighten the safety belt 10.

[0057] Furthermore, an evaluation and control unit 20 is indicated, which can control both the electric motor 15 and the pyrotechnic end fitting tensioner 19 via signal and control lines S.

[0058] The evaluation and control unit 20 is also connected via signal technology to an environment sensor 21, an acceleration sensor 22 and an occupant detection system 23.

[0059] The environmental sensor system 21 can include, for example, camera systems, radar systems and / or ultrasonic sensors. The environmental sensor system 21 serves to detect the surroundings of the motor vehicle K, for example, potential collision obstacles.

[0060] The acceleration sensor system 22 comprises acceleration sensors that can detect accelerations that may indicate an impact or crash of the motor vehicle K. For example, the acceleration sensor system 22 can measure longitudinal, lateral, roll, and yaw accelerations.

[0061] In the present embodiment, the motor vehicle K moves towards an object O that is not part of the vehicle at the vehicle speed v.

[0062] If the evaluation and control unit 20 determines, based on the signals 21 from the environmental sensors 21, that an impact on the object O appears unavoidable, the evaluation and control unit 20 outputs a corresponding control signal to the electric motor 15 (as a component of the occupant restraint device 1).

[0063] The control signal is designed in such a way that it causes the electric motor 15 to rotate in a direction DR such that the safety belt 10 is wound up in the direction R1 and thus tightened.

[0064] In this way, any existing slack in the seat belt between the occupant IN and the seat belt 10 is first eliminated, and the occupant IN is additionally pulled into a stable sitting position against the seat back 5 by the seat belt 10.

[0065] If the evaluation and control unit 20 subsequently detects an impact of the vehicle K on the object based on the signals from the acceleration sensor 22, the evaluation and control unit 20 controls the electric motor 15 in the opposite direction of rotation DR. This causes the belt winding device 13 to unwind the seat belt 10 in the direction of R2, thus releasing it at least partially. This will be explained in more detail later using the Fig. 2 and 3 will be explained in more detail.

[0066] The release of the safety belt 10, i.e. the unfolding in the direction of R2, can be controlled due to the self-locking gearbox 14.

[0067] Therefore, if, in the event of an impact, a force is exerted on the seat belt 10 in the direction of R2 due to the inertial force of the occupant IN, the unfolding of the seat belt 10 in the direction of R2 is released in a controlled manner up to a certain maximum value of a distance.

[0068] In the described pre-crash phase, during which the seat belt 10 is wound up in the direction of R1, the current flowing from a voltage source 7 to the electric motor 15 is continuously monitored by a current measuring device 24. The current measurement allows conclusions to be drawn about the magnitude of the belt force acting on the occupant IN by the seat belt 10. This force should not exceed a certain gradient and / or a maximum value at any time during the pre-crash phase, as will be explained later.

[0069] In contrast, during the crash phase, i.e. when the safety belt 10 is unwound in the direction of R2, the unwound path is constantly monitored by a rotary angle sensor 25 which is connected to the electric motor 15 via a signal.

[0070] It should be noted that in electric vehicles, it is advantageous to use the high-voltage electrical system, i.e. the traction battery, as the voltage source 7 in order to enable higher performance of the electric motor 15 even with lower currents and cable cross-sections.

[0071] Based on the Fig. 2 The pre-crash phase will now be explained in more detail.

[0072] As previously described, upon detection of an unavoidable impact on object O, the seat belt 10 tightens in the direction of R1. The occupant is thereby pulled by the seat belt 10 in the direction of R5, i.e., towards the seat back 5. A belt force F1 acts on the occupant IN, which is directed against the expected forward displacement direction R4 caused by the impact.

[0073] The electric motor 15 is to be controlled in such a way that the gradient (the increase) or the maximum of the belt force F1 does not exceed a certain value at any time.

[0074] In the Fig. 3In the depicted crash phase, an impact on object O is already detected based on the data from the acceleration sensor 22. This causes the pyrotechnic airbag device 30 to be controlled by the evaluation and control unit 20 in such a way that an airbag 31 is ignited and extends from the steering wheel 3 towards the occupant IN.

[0075] Due to the mass of occupant IN, an inertial force F2 acts on occupant IN. To prevent the reaction force exerted on occupant IN by the seat belt 10 from becoming too great, the seat belt 10 is unwound in a controlled manner in the direction of R2 such that a forward displacement of occupant IN in the direction of R4 over a distance I is possible. IN' and IN" already indicate forward displacement positions of occupant IN.

[0076] Based on data from the acceleration sensors 22, which provide information about the severity of the impact, and also based on data from the occupant detection 23, taking into account the position of the occupant IN, i.e. the position of the seat cushion 4 and the seat backrest 5 as well as the inflation path of the airbag 31, a maximum available travel distance Imax (maximum usable forward displacement path) is calculated.

[0077] The calculated forward displacement path Imax is appropriately fully utilized during the crash phase, and accordingly, a controlled unwinding of the safety belt 10 in the direction of R2 also takes place via this path.

[0078] Thus, maximum protection of the occupant with maximum safety is guaranteed even during the crash phase.

[0079] As mentioned, during the crash phase, according to Fig. 2During the winding of the safety belt 10 in the direction of R1, the current consumption of the electric motor 15 is continuously monitored, thereby controlling the belt force F1 acting on the occupant IN. This is advantageously also done with the aid of data from the environmental sensors 21 regarding the expected impact severity (relative velocity to object O, mass of object O, overlap with object O, and the like). Likewise, in the pre-crash phase, the occupant detection system 23 can also be used to supply data on the occupant's position, weight, size, and belt fastening status to the evaluation and control unit 20, and to control the force level of the belt force F1 based on this data.

[0080] If, in exceptional cases, an unavoidable impact on object O is not detected or is detected late by the environmental sensors 21, the aforementioned pyrotechnic end tensioner 19 serves as a fallback position. Upon detection of an impact on object O, the pyrotechnic end tensioner 19 is activated in such a way that the safety belt 10 is still tightened in the direction of R3 (compare Fig. 1 ) becomes possible.

[0081] In summary and conclusion, the procedure will be explained again using the following examples: Fig. 4 This will be briefly illustrated. The graph shows the force F1(t) of the belt force F1 over time t. The graph also shows the current consumption of the electric motor 15 over time t.

[0082] At time T0, the vehicle K collides with object O. As early as time T0-6t, the environmental sensors 21 detected an impact with object O that appeared unavoidable. The phase from time T0-6t to time T0 is to be referred to as process phase 1 (pre-crash phase). The period from time T0 to time T0+t is to be referred to as process phase 2 (in-crash phase).

[0083] It is noticeable that the process is carried out in such a way that process phase V1 is several times longer than process phase V2 (not shown in the drawing). Preferably, process phase V1 is approximately six times longer than the duration of process phase V2. Other duration ratios are also conceivable, deviating from the exemplary embodiment. For example, approximately equal durations for process phases V1 and V2 are also quite possible.

[0084] Through the Extending the pre-crash phase V1 compared to conventional methods allows for a reduction in seatbelt slack and forward movement of the occupant IN at an early stage. In particular, a longer duration of action allows for coupling of the occupant IN to the vehicle K with lower power input. The power input corresponds to the effect of a pyrotechnic seatbelt pretensioner operating for a very short period. However, the longer duration allows for a much gentler seatbelt pretensioning process for the occupant IN.

[0085] Furthermore, the use of the electric motor 15 and thus the reversible design of the process phase V1 makes it possible at any time to reverse the triggering decision, i.e. the belt winding (belt tightening), for example if the absence of an impact with the object O is detected based on the environmental sensors 21.

[0086] During process phase V1, the current draw of the electric motor 15 is continuously monitored to ensure that the increasing force F1(t) during this phase does not exceed a specific force gradient G. The force gradient G, i.e., the increase in the belt force F1, is determined by the ratio of ΔF to Δt. Thus, in process phase V1, the seat belt 10 is retracted under force.

[0087] In process phase V2, however, the belt force F1 is no longer monitored. Here, the belt force F1 acting on the occupant IN is adjusted solely by the controlled unwinding of the safety belt 10 over a predetermined distance. Process phase V2 is therefore characterized by displacement control.

[0088] This ensures that, even in the V2 process phase, the belt force F1 does not exceed a certain force gradient G or a limit value of a force maximum Fmax. Reference symbol list

[0089] 1 Occupant restraint device 2 Instrument panel 3 Steering wheel 4 Seat cushion 5 Seat backrest 6 Headrest 7 Power source 10 Seat belt 11 Deflection device 12 Belt movement device 13 Belt retractor 14 Self-locking gearbox 15 Electric motor 16 Belt end fitting 17 Belt buckle 18 Belt tongue 19 Pyrotechnic end fitting tensioner 20 Evaluation and control unit 21 Environmental sensors 22 Acceleration sensors 23 Occupant detection 24 Current measuring device 25 Rotation angle sensor 30 Pyrotechnic airbag system 31 Airbag D Axis of rotation DR Direction of rotation F1 Belt force F2 Inertial force F1(t) Belt force curve Fmax Maximum force G Force gradient IN, IN', IN" Occupant K Vehicle I Distance traveled by forward displacement Imax Maximum available forward displacement path O Object not belonging to the vehicle R1-R5 Directions S Signal and control lines t Time T0 Time of impact v Vehicle speed V1 Process phase 1 (Precrash phase) V2 Process phase 2 (Incrash phase) ΔF delta F Δt delta t

Claims

1. Method for actuating at least one component of an occupant restraint device (1) for a motor vehicle (K), in which method, at least in the event of an apparently unavoidable collision with an object (O) not belonging to the vehicle, the at least one component is actuated in one process phase (V1) such that the occupant restraint device (1) exerts a force (F1) on the occupant (IN), which is directed against an expected, collision-induced forward displacement direction (R4) of the occupant (IN), the at least one component being actuated in one process phase (V1) such that a defined gradient (G) and / or a defined maximum (Fmax) of the force (F1) acting on the occupant (IN) is not exceeded, and in another, subsequent process phase (V2), the at least one component being actuated such that a forward displacement of the occupant (IN) over a defined or definable distance (I, Imax) is permitted, the at least one component being an electric motor (15) of a belt movement apparatus (12), which electric motor is actuated in one process phase (V1) such that a safety belt (10) of the occupant (IN) is tensioned and a defined gradient (G) and / or a defined maximum (Fmax) of current consumption of the electric motor (15) is not exceeded, and, in the other process phase (V2), the electric motor (15) is actuated in an opposite direction of rotation (DR) such that a forward displacement of the occupant (IN) is allowed, a rotation of the electric motor (15) being permitted only up to a defined limit value of a distance (I) of the forward displacement of the occupant (IN), characterized in that, in one process phase (V1), the process functions on the basis of data from an environment sensor (21) and, in the other process phase (V2), the process functions on the basis of data from an acceleration sensor (22), at least one further component of the occupant restraint device (1) being moved pyrotechnically upon detection of a collision from the data from the acceleration sensor (22), which collision had not previously already been detected by the environment sensor (21) as unavoidable, the at least one further component being in the form of a pyrotechnic tensioner which is pyrotechnically ignited, the pyrotechnic tensioner being in the form of an end-fitting tensioner (19) or being installed in the same location as the electromotively operated belt movement apparatus (12).

2. Method according to claim 1, characterized in that a maximum available forward displacement path (Imax) for the collision in the interior is determined as the limit value of the distance (I) of the forward displacement.

3. Method according to either of the preceding claims 1 or 2, characterized in that the defined gradient (G) and / or the maximum (Fmax) of the current consumption and / or the limit value of the distance (I) of the forward displacement of the occupant (IN) can also be determined depending on an expected severity of the collision.

4. Method according to any of the preceding claims 1 to 3, characterized in that the defined gradient (G) and / or the maximum (Fmax) of the current consumption and / or the limit value of the distance (I) of the forward displacement of the occupant (IN) can also be determined depending on captured data relating to the occupant (IN).

5. Method according to any of the preceding claims, characterized in that the forward displacement is controlled over its distance (I).

6. Method according to any of the preceding claims, characterized in that the duration (t) of one process phase (V1) is at least several times longer than the duration (t) of the other process phase (V2).

7. Method according to claim 6, characterized in that the duration (t) of one process phase (V1) is approximately 4 to 7 times, preferably approximately 6 times, the duration (t) of the other process phase (V2).

8. Method according to any of the preceding claims, characterized in that a high-voltage source is used as an electrical voltage source (7) for moving the electric motor (15).

9. Occupant restraint device (1) for carrying out the method according to any of the preceding claims, comprising at least one safety belt (10), a belt movement apparatus (12) and a belt end-fitting (16) having a belt buckle (17), an environment sensor (21), an acceleration sensor (22) and an evaluation and control unit (20), the belt movement apparatus (12) being movably coupled to at least one electric motor (15) and being movable in two opposite directions by the electric motor (15), the evaluation and control unit (20) being signal-transmittingly connected to the environment sensors (21) and the acceleration sensors (22) and the evaluation and control unit (20) being configured to control the electric motor (15) via signal and control lines (S), characterized by at least one further component in the form of a pyrotechnic tensioner, which is pyrotechnically ignited by the evaluation and control unit (20) if a collision is detected from the data from the acceleration sensors (22), which collision had not previously already been detected by the environment sensors (21) as unavoidable, the pyrotechnic tensioner being in the form of a pyrotechnic end-fitting tensioner (19) by means of which the belt end-fitting (16) can be moved, or the pyrotechnic tensioner being installed at the same location as the electromotively operated belt movement apparatus (12).

10. Occupant restraint device (1) according to claim 9, characterized in that the electric motor (15) is movably coupled to the belt movement apparatus (12) via a self-locking gear (14).

11. Motor vehicle (K) characterized by at least one occupant restraint device (1) according to any of claims 9 or 10.