Impact detection sensor

Abstract

A sensor (1) for impact detection for a vehicle comprising at least one first pressure sensing means (S1) in a housing for mounting the sensor (1) in the vehicle and at least one first pressure hose (DS, DS1, DS2) connected to the first pressure sensing means, characterized in that the first pressure hose (DS, DS1) is arranged in the vehicle such that a first section (1) is arranged in the first pressure hose (DS, DS1) upstream of a second section (A2) with respect to the impulse direction of an impact, wherein a first barrier (B1) is arranged between the first section (A1) of the first pressure hose (DS, DS1) and the second section (A2) of the first pressure hose (DS, DS1) such that the first barrier (B1) attenuates a pressure impulse resulting from the impact acting on the first section (A1) of the first pressure hose (DS, DS1) before the pressure impulse acts on the second section (A2) of the first pressure hose (DS, DS1). has an effect.

Description

[0001] The present invention relates to a sensor for impact detection according to the preamble of the main claim. State of the art

[0002] From DE 10 2011 108 627 A1, an impact sensor consisting of at least two deformable hollow bodies and at least one pressure sensor for detecting the pressure change in the respective hollow body is known, wherein the pressure sensors are arranged in a common housing and a pressure supply line area sealed against the other is provided in the housing for each pressure sensor. Disclosure of the invention

[0003] Against this background, the present invention provides a sensor for impact detection in a vehicle, comprising at least one first pressure sensing element in a housing for mounting the sensor in the vehicle and at least one first pressure hose connected to the first pressure sensing element. In the sensor according to the present invention, the first pressure hose is arranged in the vehicle such that a first barrier is arranged between a first section of the first pressure hose and a second section of the first pressure hose. This first barrier is arranged such that it attenuates a pressure pulse acting on the first section of the first pressure hose before the pressure pulse acts on the second section of the first pressure hose.

[0004] In this context, a barrier can be understood as a component that is suitable for weakening a pressure impulse, which, for example, acts on the sensor as a result of an impact, in such a way that the impulse essentially no longer acts on elements that are arranged behind the barrier with respect to the direction of the pressure impulse.

[0005] The invention is based on the understanding that, in a sensor with a pressure hose, laying the pressure hose in loops can lead to the formation of multiple pressure waves within the hose following an impact. These waves would cancel each other out or weaken each other excessively. This cancellation or weakening results in the loss of information that could be derived from the nature of the pressure waves detected by the pressure sensing means.

[0006] By placing such a barrier between a first section and a second section of the first pressure hose, this annihilation is advantageously prevented.

[0007] According to one embodiment of this sensor, the sensor further comprises a second pressure sensing means connected to the at least one first pressure hose, wherein the first and the second pressure sensing means are arranged together in the housing.

[0008] By providing a second pressure sensing device connected to the pressure hose, it is easily possible to determine the point of impact by measuring the time-of-flight differences between the detected pressure waves that occur as a result of an impact in the pressure hose.

[0009] Because the first and second pressure sensing elements are located together in the sensor housing, advantages arise in terms of installation and wiring effort when mounting the sensor in the vehicle. Now, only the pressure hose needs to be routed and only one housing needs to be mounted on the vehicle. Furthermore, it is sufficient to provide only one set of connection cables for power supply and communication with the other components, such as the other control units in the vehicle, especially the control unit for activating personal protection and pedestrian protection devices, i.e., the airbag control unit.

[0010] According to one embodiment of the sensor of the present invention, the first barrier is formed from an elastic material.

[0011] By constructing the barrier from an elastic material, or a material that is not so rigid and can yield, impulses acting on the pressure hose are coupled more strongly into the section of the hose located in front of the barrier (relative to the direction of the impulse) than into the section located behind the barrier. As a result, the connected pressure sensors detect two pressure waves of different intensities when responding to an impact. The difference in travel time between these waves allows for a simple determination of the point of impact.

[0012] According to this embodiment of the sensor of the present invention, the determination of the impact point is also possible when only one pressure sensing means is used to detect the pressure waves. This has the advantage that a second or further pressure sensing means can be dispensed with in the sensor, and the sensor can therefore be manufactured very cost-effectively.

[0013] According to a further development of the sensor of the present invention, the first pressure hose is arranged in the vehicle in such a way that a second barrier acts on the pressure hose, so that as a result of an impact a further pressure signal is generated in the sensor.

[0014] Specifically, the second barrier is located behind the second section of the pressure hose in the direction of the impulse.

[0015] According to this embodiment, a further pressure signal is advantageously coupled into the pressure hose by the impulse of the impact and the counterforce of the second barrier. This is particularly true when the impact is so strong that the pressure impulse overcomes, and thus penetrates, the first barrier.

[0016] According to an alternative embodiment of the impact detection sensor for a vehicle of the present invention, the sensor comprises at least a first pressure sensing means and a second pressure sensing means, which are jointly arranged in a housing for mounting the sensor in the vehicle, as well as at least a first pressure hose connected to the first pressure sensing means and a second pressure hose connected to the second pressure sensing means.

[0017] The first and second pressure hoses are filled with different media.

[0018] Specifically, one of the media is water. Other fluids are also conceivable, such as gas mixtures, e.g., air, or liquids, e.g., oils with a predetermined viscosity.

[0019] Such different fillings exhibit different properties with regard to the propagation speed of a mechanical wave, such as a pressure wave in this case.

[0020] Given known propagation speeds in the different filling media, the point of impact on the vehicle can be easily determined from the differences in transit time, i.e., the time differences of the impact time of the pressure waves on the respective connected pressure measuring devices.

[0021] Alternatively or in addition to the embodiment with different filling media, the first and second pressure hoses have different diameters.

[0022] It is particularly important if the inner diameters of the first and second pressure hoses are different.

[0023] According to further training, the ends of the pressure hoses are connected to each other so that, in the event of a collision, stress peaks for the pressure hose can be reduced, since the filling media usually have different coefficients of expansion.

[0024] The cross-sectional area of ​​a conductor, in this case the diameter of the pressure hose(s), influences the resistance encountered by the fluid within the conductor. For example, a larger fluid flow can pass through a hose with a large diameter or large inner diameter than through a thin hose.

[0025] This embodiment is based on the understanding that the resistance changes along the length of the conductor, and therefore, with a small pressure difference, the point of impact is close to the at least two detection elements, and with a large pressure difference, it is further away from the at least two detection elements. The point of impact can thus be determined by evaluating the pressure difference.

[0026] According to an advantageous embodiment, the first and second pressure hoses are designed as twin hoses.

[0027] This design of the pressure hose as a twin hose offers particular advantages in the assembly of the hose, since now only one connected object needs to be assembled and not each pressure hose individually.

[0028] Another aspect of the present invention is a pressure sensing means according to the dependent claim of the present invention.

[0029] This aspect of the invention is based on the realization that, in order to detect an impact, not only the measurement of the absolute pressure can be used, but also the measurement of the differential pressure.

[0030] The pressure sensing device includes a first port for connecting a first pressure volume to be measured and a second port for connecting a second pressure volume to be measured. The first and second pressure volumes are separated from each other within the device by a membrane, and a pressure difference between the first and second volumes is detected based on a change in the membrane.

[0031] According to a specific embodiment, the pressure difference is detected by means of a strain gauge that detects a change in the membrane.

[0032] A strain gauge provides a cost-effective means for detecting changes in the membrane. Therefore, this embodiment of the pressure sensing device of the present invention can be manufactured inexpensively.

[0033] According to a further embodiment of the pressure sensing means of the present invention, the first pressure volume is a reference pressure volume.

[0034] Specifically, the environment around the pressure sensing device or a pressure volume with a predetermined reference pressure serves as the reference volume.

[0035] The print volume with a predetermined reference pressure can primarily be planned or set during the production of the pressure detection device.

[0036] Another aspect of the present invention is the use of the pressure sensing means described above in a sensor according to the present invention.

[0037] This use makes it possible to dispense with one of the at least two pressure sensing means in embodiments of the sensor according to the present invention which rely on the use of at least two pressure sensing means.

[0038] According to this aspect of the invention, instead of two pressure sensing means, one pressure sensing means is used, as described above. This pressure sensing means has two connections. Thus, depending on the embodiment of the sensor according to the present invention, one connection of the first pressure hose can be connected to one connection of the pressure sensing means, or alternatively, the two pressure hoses can each be connected to one connection of the pressure sensing means.

[0039] This allows costs to be saved, thus, according to this aspect of the invention, the sensor of the present invention can be manufactured cost-effectively.

[0040] Embodiments of the present invention are illustrated and explained below with reference to the figures. The figures show:

[0041] Fig. 1 a block diagram of an embodiment of an impact sensor from the prior art;

[0042] Fig. 2 a block diagram of an alternative embodiment of an impact sensor from the prior art;

[0043] Fig. 3 a block diagram of an embodiment of an impact sensor according to the present invention;

[0044] Fig. 4 a block diagram of a further embodiment of an impact sensor according to the present invention;

[0045] Fig. 5 a block diagram of a further embodiment of an impact sensor according to the present invention.

[0046] Fig. Figure 1 shows a block diagram of an embodiment of an impact sensor. 1This is a prior art diagram. It shows two pressure sensing devices, S1 and S2, connected by a pressure hose DS. Such a pressure hose DS can, for example, be made of silicone and filled with air.

[0047] In the event of a collision, the pressure sensing devices S1 and S2 detect a pressure increase caused by the propagation of a pressure wave resulting from the collision or impact on the sensor. 1 or on a vehicle structure in whose vicinity the sensor 1 was attached to the vehicle.

[0048] The measured signals from the pressure sensing devices S1, S2 are sent to another control unit, in the example shown to the airbag control unit AB-ECU.

[0049] The pressure sensors S1 and S2 are typically located to the left and right of the vehicle's bumper. The airbag control unit AB-ECU is typically located in or on the transmission tunnel / wiring duct of the vehicle, approximately at the level of the handbrake.

[0050] In Fig. Figure 1 represents an impact object, depicted as a circle marked with a lightning bolt. The impact of the object on the pressure hose DS causes a pressure wave that propagates from the point of impact P. Propagation in both directions is represented by arrows. The length of the arrows is intended to represent the propagation distance within a fixed time, and thus the propagation speed.

[0051] It is clearly evident that the pressure wave propagating in the pressure hose DS will reach the pressure sensing device S2 earlier than the pressure sensing device S1.

[0052] The point of impact P of the object can be determined from the time difference of the impact of the pressure wave.

[0053] The determination of the impact location can be performed in the airbag control unit AB-ECU. However, it is conceivable that the determination takes place in the impact sensor, for example in one or both pressure sensing elements S1 and S2.

[0054] The measurement with the pressure hose DS can only be carried out if there is a more solid component behind the pressure hose DS that provides the necessary counterforce against the impacting object, causing the pressure hose DS to be crushed and a pressure wave to build up.

[0055] An advantage of this type of impact sensor is the wide, continuous coverage of the vehicle front with a single pair of pressure sensing means S1, S2.

[0056] Fig. Figure 2 shows a block diagram of an alternative embodiment of a prior art impact sensor. Here, the two pressure sensors S1 and S2, now arranged one above the other, are shown. For example, the two pressure sensors S1 and S2 can be housed together in a single enclosure. This means that only one connection to the airbag control unit AB-ECU is required. This system design also enables preprocessing of the sensor signals, thereby reducing the communication load with the airbag control unit AB-ECU.

[0057] In the illustrated embodiment, the pressure hose is approximately twice as long as according to the embodiment shown. Fig. 1.

[0058] Depending on the design variant, the double hose may be connected at the end. For example, as shown in Fig. 2. Alternatively, the pressure hose DS can be designed so that there is no connection between the first pressure sensing device S1 and the second pressure sensing device S2. This allows two independent measurements to be taken.

[0059] Fig. Figure 3 shows a block diagram of an embodiment of an impact sensor according to the present invention.

[0060] Problematic in the Fig. The embodiment shown involves the use of a seamlessly connected double hose, a so-called “twin hose”.

[0061] To generate a pressure wave in the pressure hose DS, a certain counterforce must be applied so that the pressure hose DS is compressed. If a force is applied to a "twin hose," then both sections A1 and A2 of the pressure hose DS are compressed simultaneously, resulting in no time difference between the detected signals.

[0062] The pressure waves at both pinched points of the pressure hose DS should be approximately the same size, causing the opposing waves to cancel each other out.

[0063] What remains is a pressure signal that arrives at both sensors at the same time, thus negating the advantage of using two pressure sensing devices S1 and S2.

[0064] Fig. Figure 4 shows a block diagram of a further embodiment of an impact sensor according to the present invention. Here, a ring-shaped or loop-shaped pressure hose DS is shown.

[0065] The front section A1 of the hose, i.e., the section first reached with respect to the direction of impact momentum, can now be pressed against a first barrier B1, shown in orange. This means that upon impact, the first barrier B1 generates a counterforce which, together with the momentum from the impact, is sufficient to create a single pressure wave in the pressure hose DS, which can then propagate throughout the entire pressure hose DS.

[0066] In Fig. 4 is one embodiment of the sensor. 1 as illustrated in the present invention, wherein the first pressure hose DS is arranged in the vehicle such that a second, black barrier B2 acts on the pressure hose DS and that as a result of an impact a further pressure signal is generated in the pressure sensing means S1, S2.

[0067] This arrangement in relation to the second, black barrier B2 represents an optional or alternative arrangement of the pressure hose DS of the impact sensor. 1 of the present invention.

[0068] An advantage of this embodiment is that in the event of collisions that penetrate the first, orange barrier, a further, weaker pressure signal can be generated.

[0069] In another embodiment, the orange-colored, first barrier B1 is not completely rigid but can yield slightly. The signals in the upper and lower sections, or in relation to the impulse direction of an impact in the front section A1 and rear section A2, are then of different intensities, thus reducing cancellation in the connected area and allowing the corresponding pressure waves to be evaluated. The wave in the upper or front section A1 will be stronger than the wave in the lower or rear section A2 because energy is absorbed by the structure, particularly by the orange barrier B1, in front of the lower or rear section A2.

[0070] The point of impact P can be determined by evaluating the difference in travel time between the strong and weakened wave.

[0071] According to another embodiment, one of the two pressure sensing devices S1 or S2 could be omitted. Assuming sensing device S1 were omitted, then sensing device S2 could first receive the weaker rear signal and subsequently the stronger front signal.

[0072] The first (rear) signal can be measured, which can then be taken into account in the subsequent front signal.

[0073] Fig. Figure 5 shows a block diagram of a further embodiment of an impact sensor according to the present invention.

[0074] According to this embodiment, two pressure hoses DS1 and DS2 are used, which are filled with different filling media M1, M2.

[0075] The fillings exhibit different properties with regard to the propagation speed of a mechanical wave (pressure wave).

[0076] For example, the detection device S1 can be connected to a pressure hose DS1 filled with air M1, and the detection device S2 can be connected to a pressure hose S2 filled with water M2.

[0077] Sound propagates more slowly in air (M1) than in water (M2). Fig. In Figure 5, this is represented by the different arrow lengths.

[0078] Given a known propagation speed in the respective filling media M1, M2, the point of impact on the vehicle can be determined from the difference in the travel time of the pressure wave between the two detection devices S1, S2.

[0079] According to a variant of this embodiment not shown, the pressure hoses DS1, DS2 are designed as a “twin hose”. QUOTES INCLUDED IN THE DESCRIPTION

[0080] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0081] DE 102011108627 A1

[0002]

Claims

[1] Sensor ( 1 ) for impact detection for a vehicle comprising at least one first pressure sensing means (S1) in a housing for mounting the sensor ( 1 ) in the vehicle and at least one first pressure hose (DS, DS1, DS2) connected to the first pressure sensing device, characterized by that the first pressure hose (DS, DS1) is arranged in the vehicle such that a first barrier (B1) is arranged between a first section (A1) of the first pressure hose (DS, DS1) and a second section (A2) of the first pressure hose (DS, DS1) such that the first barrier (B1) weakens a pressure pulse acting on the first section (A1) of the first pressure hose (DS, DS1) before the pressure pulse acts on the second section (A2) of the first pressure hose (DS, DS1). [2] Sensor ( 1) according to claim 1, further comprising a second pressure sensing means (S2) connected to the at least one first pressure hose (DS, DS1), wherein the first and the second pressure sensing means (S1, S2) are arranged together in the housing. [3] Sensor ( 1 ) according to claim 1 or 2, wherein the first barrier (B1) is formed from an elastic material. [4] Sensor ( 1 ) according to one of the preceding claims, wherein the first pressure hose (DS, DS1) is arranged in the vehicle such that a second barrier (B2) acts on the first pressure hose (DS, DS1) and that as a result of an impact a further pressure signal is generated in the sensor, in particular wherein the second barrier (B2) is arranged in the direction of the impulse behind the second section (A2) of the pressure hose (DS, DS1). [5] Sensor ( 1) for impact detection for a vehicle comprising at least one first pressure sensing means (DS, DS1) and one second pressure sensing means (DS2), wherein the first and the second pressure sensing means (DS, DS1, DS2) are jointly housed in a casing for mounting the sensor ( 1 ) are arranged in the vehicle and include at least one first pressure hose (DS, DS2) connected to the at least one first pressure sensing means (S1) and a second pressure hose (DS2) connected to the second pressure sensing means (S2), characterized by that the first and second pressure hoses (DS, DS1, DS2) are filled with different media (M1, M2), wherein in particular one of the media is water (M2) and / or in particular the first and second pressure hoses (DS, DS1, DS2) have different diameters, in particular different inner diameters. [6] Sensor ( 1) according to claim 5, wherein the first and second pressure hoses (DS, DS1, DS2) are designed as twin hoses. [7] Pressure sensing means (S1, S2) comprising a first port for connecting a first pressure volume (DS, DS1) to be sensed and a second port for connecting a second pressure volume (DS2) to be sensed, wherein the first and second pressure volumes (DS, DS1, DS2) in the pressure sensing means (S1, S2) are separated from each other by a membrane and a pressure difference between the first and second pressure volumes (DS, DS1, DS2) is sensed based on a change in the membrane. [8] Pressure sensing means (S1, S2) according to claim 7, wherein the first pressure volume (DS, DS1) is a reference pressure volume, in particular the environment around the pressure sensing means or a pressure volume with a predetermined reference pressure. [9] Use of a pressure sensing means (S1, S2) according to claim 7 or 8 in a sensor (1 ) according to any one of claims 1 to 6.

Images