Impact sensor with a deformable hollow body containing a multitude of hollow chambers

Abstract

Impact sensor with a deformable hollow body (1.R,1.M,1.L), wherein the hollow body consists of an elastic plastic wall and has at least one pressure sensor for detecting the pressure change in the hollow body upon impact, wherein the hollow body and / or the pressure sensor has at least one pressure equalization opening to the environment, characterized by the fact that the hollow body has a plurality of hollow chambers (15) which are arranged perpendicular to each other and are separated from each other by wall sections (13, 14), wherein the hollow chambers (15) are connected to each other by means of pressure-permeable through-openings (16) to form a common hollow body and the hollow chambers (15) are held together section by section by retaining sections (11) of the plastic wall perpendicular to the direction of impact, wherein the retaining sections (11) are arranged on one side in the direction of impact and the shape of the hollow chambers (15) and / or the wall sections (14) separating the hollow chambers are shaped such that, in the event of an impact, at least the wall sections (14) of the directly impacted hollow chamber (15) are bent in such a way that, in the event of an impact, a pressure change occurs in the hollow body (1.R,1.M,1.L) which can be detected by the pressure sensor (PSAT) connected to the hollow body.

Description

[0001] The invention relates to an impact sensor with a deformable hollow body according to the preamble of claim 1, as is known, for example, from WO 2012 / 113 362 A1 as an elastic round tube, e.g., made of silicone, and is described in particular for the early detection of a pedestrian impact and the triggering of pedestrian protection devices. Furthermore, the hollow body or pressure sensor has at least one pressure equalization opening to the environment, since changes in ambient air pressure, e.g., due to weather, changes in the vehicle's altitude, or similar effects, must not develop into a measurement error over time. To protect against moisture, so-called pressure equalization membranes were often used for this purpose.The round hose is preferably arranged inside a damping body, behind it in the direction of impact and in contact with the crossmember as a buttress. In practice, it has been found that such an arrangement requires a sufficiently rigid support, which can generally only be provided by the crossmember. However, since the exterior of the vehicle is increasingly expected to meet further functional and aesthetic requirements, and since the crossmembers often no longer cover the entire width of the vehicle, meaning the hose sensor could no longer detect the entire width, the object of the invention is to present a novel design of such an impact sensor.The hollow body according to the invention thus has a plurality of hollow chambers which are arranged perpendicular to one another and offset from each other by wall sections, wherein the hollow chambers are in turn connected to each other by means of pressure-permeable through-openings to form a common hollow body.

[0002] In addition, the hollow chambers are held together section by section by retaining sections of the plastic wall, at least on one outer side, preferably the outer side facing the outer skin of the vehicle, perpendicular to the direction of impact.

[0003] The shape of the hollow chambers, or the wall sections separating the hollow chambers, is designed such that upon impact, at least the wall sections of the directly impacted hollow chamber(s) are bent in such a way that a pressure change occurs within the hollow body, which can be detected by the pressure sensor connected to the hollow body. This can be achieved, for example, by the hollow body having a first surface and a second surface offset in the direction of impact, the surfaces being designed with different stiffnesses due to their shape and / or choice of material or thickness.

[0004] Furthermore, the surfaces on the sides, i.e. parallel to the direction of impact, can preferably be shaped in such a way as to support a defined bending, in particular wedge-shaped, folded or wave-shaped with incisions or protrusions.

[0005] In a preferred embodiment, the hollow body has a first surface which is at least approximately flat.

[0006] In the direction of impact, projections extending from the first surface are provided, at least in sections. These projections connect the hollow chambers to the first surface, perpendicular to the direction of impact and laterally, at least at their circumferential outer edges, forming a hollow body with an enclosed hollow body. At least some of the projections have incisions and / or wall sections facing the first surface, which ultimately form the individual hollow chambers within the projections. The individual hollow chambers are, in turn, connected to each other by connecting sections to form a common hollow body.

[0007] Upon impact, the shapes, their wall sections and thus ultimately also the hollow chambers are deformed at least locally relative to each other, in particular bent, so that upon impact the internal volume in the hollow body changes and thus a pressure change occurs, which is detected by the pressure sensor connected to the hollow body at least once.

[0008] Preferably, at least over a portion of the total length in the impact direction, the wall sections separating the hollow chambers, or at least the inner wall of the wall sections, are inclined in the impact direction, in particular wedge-shaped, folded, or wave-shaped. This preferably also applies to the side walls. The possibilities offered by 3D printing provide numerous design options for adapting the bending elasticity of the hollow body or the pressure change upon impact to the requirements of vehicle construction.

[0009] The hollow body is preferably attached to the outer surface of the vehicle with the retaining sections corresponding to the first surface, preferably flat, in particular by gluing.

[0010] The hollow body preferably has a majority of offset hollow chambers oriented at least in the transverse direction of the vehicle, and pressure sensors are preferably arranged transversely at both ends of the hollow body. The position of the impact can thus be derived more precisely from the differences in the travel time of the pressure signal.

[0011] It should be mentioned again that the hollow body and / or the pressure sensor has at least one pressure equalization opening to the environment. Preferably, a plurality of such openings can be arranged at the bottom of the hollow body with respect to the vehicle's vertical axis, so that any condensing moisture can drain away through these openings. It is also conceivable that the hollow body is designed with appropriate perforations.Naturally, the total area of ​​the pressure equalization opening(s) is very small in relation to the total area of ​​the internal volume of the hollow body, and the pressure equalization is many times smaller in relation to the impact. This means that the signal path is only minimally affected by the pressure equalization opening during the impact, but conversely, pressure equalization is necessary in the vehicle in the long term because pressure differences can occur due to weather conditions, different altitudes, or the not insignificant effects of heat. However, these differences always occur at a much lower rate of change compared to the impact, and the pressure equalization opening is dimensioned accordingly.

[0012] The invention is explained in more detail below with reference to exemplary embodiments and the figures. In the figures, X generally represents the direction of travel of the vehicle, Y the transverse axis of the vehicle, and Z the vertical axis of the vehicle for the purpose of understanding the orientation. The primary purpose of the impact direction is, of course, to detect collisions in or opposite to the direction of travel. However, particularly with the typically rounded corners and side areas of the vehicle, the direction of impact can also gradually transition to the transverse direction, and the present invention is naturally equally suitable for detecting side impacts.

[0013] The Fig. Figure 1 shows a vehicle from above, preferably equipped with three impact sensors 1.R, 1.M, 1.L, each of which has at least one PSAT pressure sensor arranged, but preferably with one pressure sensor at each end of each hollow body. In principle, it is conceivable that only one corresponding impact sensor extends across the entire width of the vehicle. However, due to the complex installation situation and the multitude of additional components, such as headlights, ventilation openings, and radar sensors, or the specific shape of the vehicle's front end, this is not always feasible. A particular advantage of the invention is precisely that it can be adapted very well to the respective outer skin.

[0014] The Fig. Figure 2A shows in a first view an embodiment of the impact sensor with a hollow body 1, which is arranged on the vehicle outer skin 2 via a base surface 11 as the first surface in one of the embodiments, preferably attached and glued there. This base surface 11 also forms the holding sections by which the forms designated 12 in the figure are connected to each other, the forms being already subdivided into segments by cuts 13 on the surface. However, as is shown even better in the Fig. As can be seen in 2B, this shaping extends particularly into the interior of the hollow body. Wall sections 14 are provided there, which separate the hollow body areas 15 corresponding to the respective shapes 12 from one another section by section.

[0015] On the other hand, the Fig. 2B also the pressure-permeable openings 16, which in turn connect the individual hollow chambers 15 to form a common pressure-permeable hollow body. Crucially, the impact, in particular the bending load on the hollow body, deforms the wall sections 14 and thus ultimately the individual hollow chambers 15, in particular by squeezing, compressing, or stretching them apart, causing a slight change in the internal volume of the individual hollow chambers and resulting in a pressure change within the hollow body corresponding to the impact.

[0016] Due to the retaining sections formed by the base surface 11, the stiffness of the hollow body is lower on one side, particularly the side facing the impact, than on the opposite side, which is made softer and more elastic, especially by the projections 12 and incisions 13. In principle, such a difference in stiffness could also be achieved simply by varying the thickness of the respective plastic wall, or different elastic plastic materials could be used to meet the specific requirements. For example, the surface opposite the first surface in the direction of impact could also be flat, with corresponding hollow chambers formed exclusively inside the hollow body, and the deformation by bending upon impact caused solely by the different stiffness of the two surfaces.

[0017] The Fig. 2C shows again the cross-section through the hollow body according to Fig. 2B and in particular also the inner wall sections 14 extending the incisions 13 on the outside as well as the side walls 18, which close off the hollow body laterally and are preferably also optimized with incisions or similar shapes to a defined bending direction.

[0018] Initial tests have shown that even relatively small wall sections 14 are sufficient to achieve a measurable pressure signal inside the hollow body, but the signal amplitude can be further optimized by shaping the hollow chambers and aligning the wall sections, and the elasticity of the hollow body and its long-term stability over the lifetime of a vehicle can also be improved.

[0019] This shows Fig. 3A and Fig. 3B also represents an alternative embodiment in which the hollow chambers 15 are formed by wedge-shaped, fanned-out wall sections 14A and 14B, which are arranged at an angle in the direction of impact and are designed to converge. In this embodiment, however, not only the outer surface opposite the base 11, but also the respective side walls 18 are correspondingly wedge-shaped, but are mechanically fastened and connected via the retaining sections in the base 11, and the upper chambers are further connected to each other by pressure through the connecting openings 16. As the Fig. However, as 3A also shows, the inside of the base surface 11 can already be shaped in a wedge shape, thus promoting the overall bending elasticity of the hollow body.

[0020] The Fig. 4A, Fig. 4B and Fig. Figure 4C now shows views of another embodiment. Firstly, it illustrates the Fig. 4A again the deformation of the hollow body transmitted via the outer skin of the vehicle 2 during an impact with a collision object 3, which is again attached to the outer skin 2 of the vehicle with a base surface 11 and is provided with a plurality of perpendicularly arranged projections 12 with wedge-shaped tips and intermediate incisions 13, wherein, according to the shape of the collision object 3, the directly impacted projections 12 are fanned outwards, while at the respective side areas the projections 12 are compressed towards each other, the wall sections in the interior shift accordingly towards each other and the internal volumes of the respective hollow chambers change and overall results in a significantly measurable pressure change inside the hollow body during the impact, which naturally decreases slowly again due to the pressure equalization opening.

[0021] The Fig. 4B now shows a section through a part of the Fig. 4A and shows, in addition to the slanted wall sections 14A and 14B, which form the outer wedge shape according to Fig. 4A generates a further extension of wall section 14C in the direction opposite to the direction of travel X towards the flat surface 11. In addition, the Fig. 4B the connecting openings between the respective hollow chamber sections 15 and the position of the cuts S1 to S4, which are now in Fig. 4C will be shown in more detail.

[0022] In section S1 of the Fig. In addition to the pressure-permeable openings 16, the notches 13 formed in the side wall 8 are particularly noteworthy in section 4C, as they naturally have a positive influence on the bending elasticity of the arrangement. Section S2 shows the extended wall sections 14C again, and sections S3 and S4 show in particular the inclined wall sections and the side walls 18 located further outwards in this area.

[0023] The Fig. 5A and Fig. Figure 5B now shows a further embodiment in which the hollow body is shaped to be even more flexible and only isolated retaining struts 19 connect the respective sections of the hollow body with the retaining sections 11 of the base surface, whereby the overall arrangement reacts even more strongly to the impact, in particular the opposite surfaces on the impact-facing and impact-away sides can already react differently to each other and thus an even greater overall pressure change inside the hollow body could be observed.

[0024] Due to today's 3D printing capabilities, the choice of material and shape can be adapted very closely to the requirements of the respective vehicle, its outer shape and other components in the front area or sides of the vehicle, as well as to the requirements regarding impact hardness and corresponding pressure signal reaction or elasticity over the product's lifetime. Reference symbol list 1 Hollow body of the impact sensor PSAT pressure sensor of the impact sensor 2 Outer wall of the vehicle 3 Collision Object 11 Holding section and first surface 12 shapes in the direction of impact 13 cuts opposite to the direction of impact 14 wall sections 15 individual upper chambers 16 connecting openings between the upper chambers 17 Connection to PSAT 18 side wall sections 19 landing stages X Direction of travel of the vehicle Y transverse direction of the vehicle Z vertical axis of the vehicle

Claims

[1] Impact sensor with a deformable hollow body (1.R,1.M,1.L), wherein the hollow body consists of an elastic plastic wall and has at least one pressure sensor for detecting the pressure change in the hollow body upon impact, wherein the hollow body and / or the pressure sensor has at least one pressure equalization opening to the environment, characterized by , that the hollow body has a plurality of hollow chambers (15) which are arranged perpendicular to each other and are separated from each other by wall sections (13, 14), wherein the hollow chambers (15) are connected to each other by means of pressure-permeable through-openings (16) to form a common hollow body and the hollow chambers (15) are held together section by section by retaining sections (11) of the plastic wall perpendicular to the direction of impact, wherein the retaining sections (11) are arranged on one side in the direction of impact and the shape of the hollow chambers (15) and / or the wall sections (14) separating the hollow chambers are shaped such that, in the event of an impact, at least the wall sections (14) of the directly impacted hollow chamber (15) are bent in such a way that, in the event of an impact, a pressure change occurs in the hollow body (1.R,1.M,1.L) which can be detected by the pressure sensor (PSAT) connected to the hollow body. [2] Impact sensor according to claim 1, characterized by, that the hollow body has a first (11) and a second surface (12,13) ​​offset in the direction of impact, wherein the surfaces are designed with different stiffness due to their shape and / or choice of material or thickness. [3] Impact sensor according to claim 1 or 2, characterized by , that a first surface (11) has which is at least approximately planar, in the direction of impact, the first surface has projections (12) that extend at least sectionally from it, and connect these projections (12) perpendicularly to the direction of impact, at least at the circumferential outer edges, to the first surface of the hollow body with a cavity enclosed therein. wherein at least some of the forms (12) have incisions (13) and / or wall sections (14) directed towards the first surface, which form the individual hollow chambers (15) in the forms (12), which in turn connect to each other by connecting sections (16) to form a common hollow body (1), and In the event of an impact, the shapes (12) or wall sections (14) and / or hollow chambers (15) are at least locally bendable to each other, so that a pressure change occurs in the hollow body upon impact, which can be detected by the pressure sensor (PSAT) connected to the hollow body (17) at least once. [4] Impact sensor according to any of the preceding claims, characterized by, that at least over a section (14a,14b) of the total length in the direction of impact the wall sections separating the hollow chambers from each other or at least the inner wall of the wall section is inclined in the direction of impact, in particular wedge-shaped, folded or wave-shaped. [5] Impact sensor according to any of the preceding claims, characterized by , that the hollow body with the retaining sections (11), which are preferably arranged in the first surface, rests against the outer surface (2) of the vehicle, preferably is attached over a surface, in particular is glued. [6] Impact sensor according to any of the preceding claims, characterized by , that the hollow body (1.R,1.M,1.L) is aligned at least in the transverse direction (Y) of the vehicle and has the majority of offset hollow chambers (15) and at least one, preferably two pressure sensors (PSAT) arranged in the transverse direction at both ends of the hollow body are provided.

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