Impact protection device for a vehicle

Abstract

The invention relates to an impact protection device for a vehicle having a windscreen (1), an impact detector (2) for detecting a person impact (27) on the windscreen (1) and a weakening device (10) which, upon detection of a person impact (27), causes a mechanical load on the windscreen (1). In order to provide an optimized impact protection device for a vehicle, which, using simple and space-saving means, causes the windscreen to collapse or be destroyed only in the event of an actual collision with a person, it is intended that the attenuation device (10) comprises at least one vibration generator (12, 14), which excites mechanical vibrations (21, 22) in the windscreen (1) and thereby causes mechanical loads (23, 24) on the windscreen (1) such that that when superimposed with the mechanical loads (30) caused by a person impact (27), mechanical loads (31) result which lead to the breakage of the windscreen (1).

Description

[0001] The invention relates to an impact protection device for a vehicle having a windshield, an impact detector for detecting a person impacting the windshield, and a weakening device which, upon detection of a person impact, causes a mechanical load on the windshield.

[0002] In most head-on collisions between a vehicle and a person, e.g. a pedestrian or cyclist, the initial collision occurs with a frontal area of ​​the vehicle (e.g. the front bumper or grille). The person's body wraps around the front profile of the vehicle. This poses a high risk that the person's head will ultimately hit the front profile. The wrapping of the body around the front of the vehicle can lead to a high-speed impact and thus to a so-called body whip effect with subsequent secondary impact - e.g. on the roadway. The severity and location of the impact are determined by many factors, in particular the shape of the front of the vehicle (frontal profile) and the size of the person, which are used to determine the so-called wrap distance (WAD).The wrap distance is a determinant of the likely area of ​​head impact of the person on the vehicle.

[0003] Considerable efforts have been made in the past and are currently underway to increase the passive protection of road users. Legal requirements and related customer expectations are leading to the optimization of vehicle front-end design with these aspects in mind. To test and evaluate the passive protection of road users, so-called impactors with abstract head shapes are fired at the front area in test systems, and the respective decelerations are recorded. This allows the "Head Injury Criterion" (HIC) to be determined, which can be used to estimate the extent of potential injuries in a frontal collision.

[0004] Against this background, the windshield itself is increasingly becoming a key element in the focus of passenger impact protection, partly due to stricter legal requirements according to ECE R 127.03 and consumer tests according to European or Chinese specifications (Euro NCAP and China NCAP).

[0005] The windshield, or rather its glass, is a comparatively hard and brittle material that deforms only slightly (elastically) upon impact and therefore can hardly dissipate any impact energy, resulting in a partially elastic impact. This causes delays before the windshield ultimately fails and collapses spontaneously.

[0006] In the context of this description, the term windscreen does not only include a single, single-layer pane, but above all known multi-layer laminated compositions, for example with two layers of glass that are bonded or glued together with an intermediate layer (e.g. made of PVB (polyvinyl butyral)).

[0007] WO 2020 / 005554 A1 discloses an impact protection device for a vehicle of the type mentioned above, comprising a glass laminate and a sensor that detects a collision with a person. If a collision with a person is detected, a sensor signal activates a break mechanism that exerts a force on the glazing by means of an impact body, causing the entire glass laminate to break, which is intended to lead to improved absorption of the impact energy.

[0008] Similar devices are known from DE 10 2006 028 484 A1 and from US 2013 / 0091779 A1, each of which causes a controlled collapse of a windshield upon detected collision with a person by triggering an explosion upon impact in order to generate a destructive force acting on the windshield.

[0009] The known devices lead to activation of the breakage mechanism and thus to a breakage or destruction of the windshield even if there is actually no collision with a person or if a false detection occurs.

[0010] Against this background, one object of the present invention is to provide an optimized impact protection device for a vehicle that, using simple and space-saving means, causes the windshield to collapse or destroy only in the event of an actual collision with a person. A further object is to ensure increased and targeted energy absorption (dissipation) of the impact energy.

[0011] This object is achieved by an impact protection device having the features of patent claim 1.

[0012] Accordingly, in an impact protection device of the type mentioned at the outset, the invention provides that the attenuation device comprises at least one vibration generator which excites mechanical vibrations in the windshield and thereby causes mechanical loads on the windshield in such a way that, when superimposed with the mechanical loads which a (person) impact generates on the windshield, mechanical (total) loads result which lead to the breakage of the windshield.

[0013] In short: According to the invention, a weakening or pre-weakening of the windshield is achieved by introducing mechanical vibrations and, if necessary, controlled mode selection, with which resonances can be specifically generated, in order to achieve an increase in the mechanical stresses caused by the impact through interference, which leads to a targeted earlier collapse or earlier breakage of the windshield compared to the prior art.

[0014] The invention thus ensures that the legal requirements for passive personal protection, which are likely to become even more stringent in the future, can be met and at the same time improves the “customer rating” as an important purchasing incentive.

[0015] A key advantage of the impact protection device according to the invention is that the mechanical vibrations introduced into the windshield by the attenuation device, or the resulting mechanical loads on the windshield material, only lead to the (deliberate) collapse of the windshield when superimposed upon a collision with a person. In contrast to the prior art presented at the beginning, the windshield thus remains undamaged if no impact actually occurs.

[0016] Thus, in cases where the impact detector emits an erroneous signal ("false alarm") or where a predicted impact does not actually occur in a predictive detection, only the vibration generator(s) are excited. However, due to the lack of additional mechanical stresses caused by the impact, the windshield does not collapse. The impact protection device according to the invention or the windshield is therefore reversible and can continue to be used in the event of a "false alarm."

[0017] A further significant advantage of the invention is that the impact protection device according to the invention can be designed with little effort, elegantly and in a space-saving manner.

[0018] A particularly low-cost implementation of the impact protection device according to the invention is possible in that the detection of a personal impact is carried out by other sensors already installed in the vehicle, which detect an impending or already detected collision, such as sensors for airbag deployment.

[0019] Further advantageous embodiments and developments of the invention will become apparent from the dependent claims and the following description. Individual features can generally be used in any combination, unless explicitly excluded.

[0020] For a particularly space-saving implementation of the invention, the vibration generator(s)—hereinafter also referred to as actuators—can be coupled to the windshield in a material, force, and / or form-fitting manner to generate mechanical vibrations or loads. This can be achieved, for example, by a full-surface (transparent) coating or adhesive, or by a coating or adhesive only in the edge area—which also allows for non-transparent actuators—on the inside and / or outside of the windshield. The actuators can also be arranged between individual laminate layers of the windshield.

[0021] Another possible implementation of the invention is the coupling with external vibration generators (e.g. quartz oscillators) that generate mechanical vibrations or waves and thus initiate the mechanical loads in the windshield.

[0022] A preferred embodiment of the invention provides that the vibration generator (actuator) excites vibrations in the acoustic range or ultrasonic range.

[0023] According to one embodiment of the invention, the introduction of mechanical loads into the windshield is possible in that the vibration generator(s) excites transverse vibrations (surface waves) orthogonal to the surface of the windshield.

[0024] An alternative preferred embodiment of the invention provides that the vibration generator(s) excites longitudinal waves toward the surface of the windshield. This has the additional effect and advantage that—if desired—the longitudinal waves reduce the adhesion force between bonding layers or adhesive films of a windshield with the lamination described above through vibration-induced shear forces. This can contribute to increased dissipation in the event of a collision.

[0025] According to a preferred development of the invention, independently existing, superimposed (other) vibrations in the windshield, which are excited by other sources, are detected, and the vibration generator(s) are controlled taking these other vibrations into account. The frequency of the vibration generator(s) is modified such that the mechanical waves they generate have an optimized effect on the windshield or its fracture behavior. In cases where the other vibrations have an attenuation-enhancing effect, the vibration input from the vibration generators is reduced. In the opposite case of load compensation by the other vibrations, an increase in the vibration input from the vibration generators is possible.The other superimposed vibrations can preferably be derived from signals from existing sensors that are otherwise necessary (for example, vibrations from driving) or from acoustic or microphone-like sensors.

[0026] The introduced mechanical vibrations or the mechanical waves generated thereby can be so-called standing waves with approximately stationary maxima and minima. A preferred embodiment of the invention provides for the mechanical vibrations to move along the windshield with a maximum amplitude. Amplitude maxima that "wander" across the windshield surface represent an elegant way to specify or force preferred directions for crack propagation in the windshield without requiring any measures to be taken on the windshield itself.

[0027] According to a further advantageous embodiment of the invention, a significant increase in the efficiency of energy absorption (dissipation) in the event of a personal impact is achieved by a localization device that, upon detection of a (potential) personal impact, determines the expected impact area on the windshield or, upon detection of an actual personal impact, the actual impact area on the windshield. This device also includes an evaluation device that, depending on the determined impact area, modifies the generation of mechanical vibrations in the windshield in such a way that increased mechanical stresses arise in the impact area compared to the surroundings of the impact area. The expected impact area or point of impact on the windshield can preferably be determined by a camera, the aforementioned sensors for detecting other vibrations, or by ultrasonic probes.The vibration generators simultaneously generate transverse mechanical surface waves, each with a defined amplitude, frequency, and modes suitable for resonance in the selected area (the expected impact zone), such that the greatest stress peak occurs in the expected impact zone. This specifically increases the stresses in the impact zone to such an extent that the windshield breaks earlier or collapses more severely there.

[0028] Embodiments of the invention are explained in more detail below with reference to a drawing. They show, in a perspective schematic view: Fig. 1 shows a first embodiment of an impact protection device according to the invention, Fig. 2 a variant of an impact protection device according to the invention, Fig. 3 an embodiment of an impact protection device according to the invention with a first localization device and Fig. 4 an embodiment of an impact protection device according to the invention with a second localization device.

[0029] Fig. 1 shows an impact protection device for a (not shown) vehicle with a windshield 1 and a schematically indicated impact detector 2 for detecting an impact of a (not shown) person on the windshield 1. The term impact detector also includes a detector device composed of or interacting with several detectors. Sensors already installed in the vehicle, which detect an impending or already occurred collision, are preferably used as impact detectors. A camera (cf. Fig. 3 and Fig. 4). The sensor or impact detector 2 transmits a detector signal 4 to a control device 5 upon impact of a person or body part (in particular the head) on the windshield 1. An attenuation device 10 comprises two vibration generators (actuators) 12, 14. The vibration generators 12, 14 are supplied with excitation signals 16, 17 by the control device 5 as soon as the impact detector 2 detects an impending or already occurred impact and generates the detector signal 4.

[0030] The vibration generators 12, 14 are applied directly as a coating to a surface 18 of the windshield 1, preferably by adhesive bonding. It is also conceivable to mechanically couple external actuators, such as quartz oscillators, to the windshield in a force-fitting or form-fitting manner such that they introduce or excite corresponding vibrations into the windshield. In this exemplary embodiment, the vibration generators 12, 14 are located at the respective edge regions 19, 20 of the windshield 1—as viewed in the y-direction of the xyz coordinate system shown. They therefore do not have to be transparent. In an alternative embodiment, the vibration generators can also be transparent and cover a larger area of ​​the windshield.The vibration generators 12, 14 feed - as shown in a very exaggerated manner in the figures - vibrations (waves) 21, 22 into the windscreen 1, which cause (transverse) vibrations and thus mechanical loads 23, 24, as shown in . Fig. 1 shown schematically.

[0031] By suitable control of the vibration generators 12, 14 by the control device 5, known per se to those skilled in the art, superpositions or interferences can be generated by selecting the amplitude, frequency, and / or phase position such that the transverse wave input into the windshield 1 generates mechanical loads 23, 24 that act orthogonally to the surface 18 of the windshield 1 (in the direction of the double arrow S, i.e., in the z-direction of the xyz coordinate system). By selecting the aforementioned parameters in the control of the vibration generators 12, 14, a maximum amplitude 26 or several maximum amplitudes 26 of the vibration or load can be generated by superposition at a desired area 25.

[0032] The excitation of the vibration generators 12, 14 can be selected such that a substantially standing wave is generated on the surface 18 and thus a substantially stationary maximum amplitude 26 is established. The excitation of the vibration generators 12, 14 can preferably be selected such that the maximum amplitude 26 migrates across the surface 18, as indicated by the arrow W, transverse to the direction of vibration along the y-direction from the edge region 19 to the edge region 20. This can promote a preferred direction of the fracture paths or crack formation in the windshield in the W direction.

[0033] In the case of a schematically indicated impact 27 of an impactor 28 (here in the simulation) or, in reality, of a head, the mechanical load (stress) 23, 24 induced by the mechanical vibrations 21, 22, in conjunction with the mechanical load (stress) 30 caused by the impact 27, results in a resulting total mechanical load (stress) 31, which causes the windshield 1 to break or collapse earlier than the impact-induced mechanical load alone, and thus more impact energy can be absorbed.

[0034] This indicates the detection of independently existing (other) vibrations 35 in the windshield, which are superimposed on the vibrations 21, 22 and are excited by other sources. The control of the vibration generators 12, 14 takes these other vibrations 35 into account by modifying the frequencies of the vibration generators so that the effect on the windshield or its fracture behavior is reliable despite the vibrations 35. The superimposed other vibrations can preferably be detected from signals of other necessary sensors, here, for example, by an acoustic sensor 36, whose sensor signal 37 is applied accordingly to the controller 5.

[0035] Fig. Figure 2 shows an alternative embodiment of an impact protection device which differs from that shown in Fig. 1 essentially in that the vibration generators (actuators) 112, 114 acting on the windshield 101 generate longitudinal vibrations 105 in the direction of the double arrow L. The vibrations or mechanical loads in the windshield 101 extend in the y-direction, i.e., they are longitudinal waves with respect to the windshield 101 or its surface 118. The vibration generators 112, 114 are designed as externally coupled actuators that are force- or form-fittingly coupled to the edges of the windshield in the respective edge region 119, 120 of the windshield 101.

[0036] The longitudinal surface waves or mechanical loads formed by the longitudinal wave input have minima regions 122 with minimum amplitudes 123 generated by superposition and maxima regions 124 with maximum amplitudes 126. Otherwise, this impact protection device is essentially as in Fig. 1 shown and explained, so that with regard to the other components, for the sake of simplicity, Fig. 1 is referred to.

[0037] In the case of a schematically indicated impact 127 of an impactor 128 (here in the simulation) or, in reality, the head of a person, the induced mechanical loads 129 due to the vibrations 105 (amplitudes 126) in conjunction with the mechanical loads (stresses) 130 due to the impact 127 also lead to the windshield breaking earlier than due to the impact-induced mechanical load alone.

[0038] Fig. 3 shows a further development of the Fig. 1 already described impact protection device, in which a localization device 300 in the form of a camera 301 is provided. In the Fig. According to the localization principle illustrated in Figure 3, a prospective impact area 302 (in the test setup of an impactor 303, in real impact situations involving the head or person) is localized on the windshield 1 before the actual impact 305 (symbolized by the arrowhead of arrow A) occurs. Optical sensors are preferably used as the localization device, for example, as an alternative to the camera shown, a radar device or a so-called lidar, in which laser beams are used for optical distance and speed measurement.

[0039] The localization device supplies an evaluation device 310 with position data 312 about the expected impact area 302. Based on this position data or coordinates derived from the position data, the evaluation device 310 applies this data to the controller 5 in such a way that, by appropriately selecting the frequency and phase of the vibrations fed in by the vibration generators 12, 14, the maximum amplitude 320 is generated by interference in the impact area 302.

[0040] Fig. Figure 4 schematically shows an alternative localization principle with a localization device 400, which determines an actual impact area 402 in which contact 412 with an impactor 416 or, in reality, with a person's head already exists. The remaining components for evaluating or controlling the vibration generators and the vibration generators themselves are shown in Figure 4 for reasons of clarity. Fig. 4 are not shown again because their functions have already been explained in detail.

[0041] In this embodiment, the windshield 401 is provided with two sensors 403, 404 of the localization device 400. The sensors 403, 404 can be designed, for example, as microphones or ultrasonic probes. As shown in Fig. As indicated in Figure 4, the mechanical waves 420, 421 generated by the impact of the impactor 416 or the head with the windshield 401 (also) propagate to the sensors 403, 404. Through known time-of-flight or phase-position measurements, the impact area 402 can be localized using this acoustic sensor technology. In a corresponding manner already explained above, the output signals 425, 426 of the sensors 403, 404 are sent to an evaluation device (not shown here) (see Fig.3) which acts on the control in such a way that a maximum amplitude is set in the impact area 402. List of reference symbols 1 windshield 2 impact detectors 4 Detector signal 5 Control device 10 Attenuation device 12, 14 Vibration generators (actuators) 16, 17 Excitation signals 18 Surface 19, 20 peripheral area 21, 22 (transverse) oscillations 23, 24 mechanical loads 25 Area 26 maximum amplitude 27 Impact 28 Impactor 30 mechanical load 31 resulting mechanical stress 35 other vibrations 36 acoustic sensor 37 Sensor signal 101 Windshield 105 longitudinal oscillations (longitudinal waves) 112, 114 Vibration generators (actuators) 118 Surface 119, 120 Marginal area 122 minimum range 123 minimum amplitude 124 maximum range 125 vibrations 126 maximum amplitudes 127 Impact 128 Impactor 129 mechanical load 130 mechanical load 300 localization device 301 Camera 302 expected impact area 303 Impactor 305 actual impact 310 Evaluation device 312 Position data 320 maximum amplitude 400 localization device 401 Windshield 402 actual impact area 403, 404 Sensors 412 Contact 416 Impactor 420, 421 mechanical shafts 425, 426 output signals A Arrow L double arrow S double arrow V Preferred direction W Arrow QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] WO 2020 / 005554 A1

[0007] DE 10 2006 028 484 A1

[0008] US 2013 / 0091779 A1

[0008]

Claims

[1] Impact protection device for a vehicle with - a windscreen (1), - an impact detector (2) for detecting a person impact (27) on the windscreen (1) and - a weakening device (10) which, upon detection of a person impact (27), causes a mechanical load on the windscreen (1), characterized by , that - the attenuation device (10) comprises at least one vibration generator (12, 14) which excites mechanical vibrations (21, 22) in the windscreen (1) and thereby causes mechanical loads (23, 24) on the windscreen (1) in such a way that - that when superimposed with the mechanical loads (30) caused by a person impact (27), mechanical loads (31) result which lead to the breakage of the windscreen (1). [2] Impact protection device according to claim 1, characterized by , that - the at least one vibration generator (12, 14) is materially, force- and / or positively coupled to the windscreen (1). [3] Impact protection device according to at least one of the preceding claims, characterized by , that - the vibration generator(s) (12, 14) excites vibrations (21, 22) in the acoustic range or ultrasonic range. [4] Impact protection device according to claim 1, 2 or 3, characterized by , that - the vibration generator(s) (12, 14) excites(s) transverse vibrations (21, 22) orthogonal to the surface (18) of the windscreen (1). [5] Impact protection device according to claim 1, 2 or 3, characterized by , that - the vibration generator(s) (112, 114) excites(s) longitudinal vibrations (105) in the direction of the surface (118) of the windshield (101). [6] Impact protection device according to at least one of the preceding claims, characterized by , that - other vibrations (35) already existing and / or superimposed in the windscreen (1) which are excited by other sources are detected, and the vibration generator(s) (12, 14) are controlled taking these other vibrations (35) into account. [7] Impact protection device according to claim 6, characterized by , that - an acoustic sensor (36) is used to detect the other vibrations (35). [8] Impact protection device according to at least one of the preceding claims, characterized by , that - the mechanical vibrations (21, 22) move along the windscreen (1) with a maximum amplitude (26). [9] Impact protection device according to at least one of the preceding claims, characterized by - a localisation device (300) which, when a personal impact is detected, determines the expected or actual impact area (302, 305) on the windscreen (1) and - by an evaluation device (310) which, depending on the determined impact area (302, 305), modifies the generation of the mechanical vibrations in the windshield (1) in such a way that increased mechanical loads arise in the impact area (302, 305) compared to the surroundings of the impact area (302, 305).

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