DE102016211135A1 - Pedestrian protection device for a motor vehicle - Google Patents

Abstract

A pedestrian protection device for a motor vehicle according to the present invention has a cross member and a deformation member attached to the cross member. The deformation member includes a first member and a second member, which are slidable relative to each other due to the collision, and a biased or collision-biased locking member movably supported on one of the first member and the second member and the other of the first member and the second element in the course of the collision is positively engageable. Furthermore, the pedestrian protection device has a collision detection device with a sensor device for detecting a position or a position change of the locking element, wherein the collision detection device detects a collision state of the motor vehicle on the basis of the position or the position change of the locking element.

Description

The present invention relates to a pedestrian protection device for a motor vehicle with a deformation element which is mounted on a cross member.

For example, a known front end of a motor vehicle has a bumper cross member attached to front ends of side rails and a bumper fascia. Between the bumper fascia and the bumper cross member, an energy absorbing element made of a soft, deformable on a comparatively low load level foam is placed to protect pedestrians. The soft foam is positioned to protect pedestrians from direct direct collision with a hard, rigid structure such as the bumper cross member due to pedestrian protection. Furthermore, a collision detection sensor system on the basis of a pressure measurement or by means of a Lichwellenleiters or a piezoelectric sensor is known. The collision detection sensor serves to detect a collision with a pedestrian, so that a control unit based on this detection can actively instruct pedestrian protection measures, such as raising a front door or triggering a windshield airbag or the like. Such a collision detection sensor, for example, has a hose to which a pressure sensor is connected, which can detect pressure fluctuations within the tube. If the tube is deformed as a result of the collision with the pedestrian, there is a detectable pressure change in the tube interior, which is filled, for example, with air at atmospheric pressure. Such a hose may be disposed in the vehicle transverse direction in abutment with the bumper cross member and may be housed in a groove or the like in the energy absorbing member.

The foam energy absorbing member is deformed at the same level of force regardless of a collision load case. However, there is a requirement that a vehicle front be stiffer or deformed at a speed that is not relevant to pedestrian protection, for example at a low speed and thus a small collision pulse, or deformed at a higher force level. This would allow at low speeds that the motor vehicle remains free of damage or damage to the motor vehicle is lower.

For this suggests the EP1386794A1 before to arrange on a cross member in the vehicle longitudinal direction and thus displaceable in the direction of collision cylinder. Further, a biased with a spring stop element is provided on the cross member which blocks depending on a displacement speed of the displaceable cylinder and thus a collision energy displacement of the cylinder.

When in the EP1386794A1 a solution mentioned above, a collision detection sensor based on a pressure tube or the like is not applicable.

It is therefore the object of the present invention to provide a pedestrian protection device which is simple in construction and functions independently of a sensor or an actuator and can additionally detect a collision by simple means. In particular, it is the object of the present invention to provide a pedestrian protection device which can detect a collision pulse.

This object is achieved by a pedestrian protection device for a motor vehicle having the features of claim 1. Advantageous embodiments of the invention are mentioned in the dependent claims.

A pedestrian protection device for a motor vehicle according to the present invention has a cross member and a deformation member attached to the cross member. The deformation member includes a first member and a second member, which are slidable relative to each other due to the collision, and a biased or collision-biased locking member movably supported on one of the first member and the second member and the other of the first member and the second element in the course of the collision is positively engageable. Furthermore, the pedestrian protection device has a collision detection device with a sensor device for detecting a position or a position change of the locking element, wherein the collision detection device detects a collision state of the motor vehicle on the basis of the position or the position change of the locking element. By detecting the position or change in position of the locking element, a collision or collision condition, i. a collision type, can be determined simply by detecting the position of the locking element. The positive engagement prevents a further relative displacement between the first element and the second element. The engagement of the locking element with the recess, a positive connection between the first element and the second element, so that a relative displacement between the first element and the second element is no longer possible.

The collision state can include, for example, a collision pulse.

As a result, the collision detection device can detect a type of collision. For example, the collision detection device may optionally distinguish between a collision pulse caused by a pedestrian or, for example, a small animal. Further, the collision detecting means may discriminate between a collision pulse caused by a low vehicle speed or a high vehicle speed.

The cross member may be a front or rear bumper cross member.

According to a preferred embodiment of the pedestrian protection device according to the invention, the locking element is designed such that it engages positively with a depression or a step (a stop) with a low collision pulse which is smaller than a predetermined collision pulse and the deformation element is thus deformable at a high load level, and that at a high collision pulse which is equal to or greater than the predetermined collision pulse jumps over the recess or the step and the deformation element is thus deformable at a low load level.

The low collision pulse includes a low shift speed of the first element and the second element due to the collision with each other. The high collision pulse includes a high displacement speed of the first element and the second element due to the collision with each other. Thus, the structure of the front and rear cars of the motor vehicle can be sufficiently rigid at a relatively low speed, so that there is no structural damage to, for example, the bumper fascia or the like due to excessive deformation. As a result, repair costs can be minimized in collisions at very low speed, such as in so-called parking bumps and limited only to the repair of example paint damage. Above a collision speed threshold relevant to pedestrian protection, the first member and the second member are not locked together and the deformation member may be changed in length with a relatively small force to protect pedestrians, i. be pushed together by relative displacement of the first element and the second element to each other.

As a result, no collision sensors and no actuators are necessary to control a locking of the deformation element as a result of the collision, depending on a collision pulse and thus a collision speed of the vehicle. Thus, by simple means utilizing a mass inertia of the biased locking element, the deformation element can be provided between a soft state in which a relative displacement between the first element and the second element over a long distance is possible, and a stiff state in which a relative displacement between the first Element and the second element is prevented or at least over a small distance is possible to be switched.

A relative displacement between the first element and the second element takes place substantially in the longitudinal direction of the motor vehicle, which is usually also a main direction in a frontal collision of the motor vehicle. A locking mechanism in the form of the first element, the second element and the locking element acts independently of a collision sensor automatically by utilizing the inertia of the prestressed locking element.

According to a preferred embodiment of the pedestrian protection device of the present invention, the sensor device is adapted to detect a latched position of the locking element and / or an unlocked position of the locking element.

Advantageously, the sensor device is adapted to detect the position or the position change of the locking element based on a contact or a missing contact between the locking element and the first element or the second element.

In particular, the collision device may be adapted to detect the position or the position change or the collision state on the basis of a time that the locking element is not in contact with the first element - when the locking element is mounted on the second element - or the second Element is - when the locking element is mounted on the first element.

According to a preferred embodiment of the pedestrian protection device, the sensor device detects the position or the position change of the locking element due to an electrical resistance between the locking element and the second element or the first element.

An electrical resistance measurement can be realized particularly inexpensively. If a circuit is interrupted, ie as long as that Locking element is not in contact with the element to which the locking element is not biased or mounted prestressed, the electrical resistance is large. As soon as the locking element is in contact with the respective element of the first element and the second element, the electrical resistance is lower.

The first element or the second element and the locking element are preferably made of an electrically conductive material. These elements are preferably made of a metallic material, for example steel.

According to a preferred development, the pedestrian protection device according to the invention has a control device which, on the basis of the position or the position change of the locking element active pedestrian protection measures, for example, a raising a front flap in a pedestrian protection position and / or triggering a pedestrian protection airbag, in particular a windshield airbag instructs.

As a result, an impact of the pedestrian on, for example, the front flap or the windscreen can be mitigated.

According to a preferred development of the pedestrian protection device according to the invention, a deformation region of the deformation element is formed between a body outer skin, in particular a bumper fascia, and the cross member, in particular the bumper cross member.

In this area, the deformation element is particularly effective as a pedestrian protection device, since the bumper cover, which is usually made of a thin-walled plastic material, is usually light in weight, i. at a low level of force, elastic or plastically deformable.

Preferably, in the pedestrian protection device, the locking element can be biased transversely, in particular perpendicularly, to the displacement direction / collision direction. According to a preferred development of the pedestrian protection device of the present invention, the locking element is pretensioned by means of a spring device or can be prestressed by means of the spring device. The spring device is advantageous in that a latching of the locking element with the recess or with the step, i. the stop is made reliably and remains.

In this case, the spring device is preferably essentially relaxed in an idle state or initial state, that is to say in a state in which no collision load acts on the deformation element.

This has the advantage that the spring device does not lose its spring tension in the idle state or initial state.

The deformation element further preferably has a contact surface, via which the locking element is movable against the spring force of the spring device and thus can be prestressed before the locking element reaches the depression or step. The contact surface is, in order to enable a movement of the locking element, formed obliquely to a longitudinal axis or deformation direction of the deformation element.

By means of this contact surface, the collision load is used for a bias of the spring device.

Preferably, the locking element, the spring means and the recess or the stage are formed cooperatively such that upon slow movement of the first element relative to the second element, the locking element engages with the recess or step and at a rapid displacement of the first element relative to the second element, the locking element does not engage with the recess or step, but jumps over the depression or step.

As a result, an automatic mechanism is provided which uses only a mass inertia of the locking element for its function. Accordingly, with a low displacement speed and thus a low collision velocity or the low collision pulse, a latching takes place and the deformation element therefore acts stiff. In the case of the fast displacement speed and thus the fast collision speed or the high collision pulse, the locking element does not engage - in the case of rapid displacement, the locking element slides or jumps in particular beyond the depression or step - and a further displacement between the first element and the second Element at a low level of force is made possible, whereby the deformation element for a total pedestrian protection is soft.

The spring device may additionally be provided with a damping device which damps a movement of the locking element suitable. For a locking / non-engagement of the locking element is suitably controlled.

Further, according to the pedestrian protection device of the present invention, the Deformation element adapted such that it can absorb collision energy in a locked state by plastic deformation and / or brittle failure of the deformation element over a predetermined deformation distance. Such a deformation distance can be, for example, 60 mm to 110 mm.

Depending on the collision load and thus the speed in the collision or depending on the collision pulse, the deformation element can thus react stiffly and transmit the collision load to the underlying crash structure of the vehicle, or a load threshold value of the locked deformation element is exceeded and it is deformed and can thus collision energy a relatively high load level to protect other components and vehicle occupants absorb.

The deformation element may have a length of 50 to 150 mm. Preferably, the deformation element may have a length between 70 and 110 mm.

Preferably, a deformation region of the deformation element has a length of 60 mm to 110 mm.

The first element may be a substantially cylindrical element which is displaceable in a corresponding guide of the second element. The locking element may be mounted on the first element or on the second element.

The second element may be firmly connected to the cross member or be part of the cross member.

The above-mentioned developments of the invention can be combined as far as possible and meaningful with each other.

Below is a brief description of the figures.

1 shows a schematic perspective view of a pedestrian protection device according to an embodiment of the present invention.

2 shows a schematic sectional view of the pedestrian protection device according to the embodiment of the present invention in an initial state.

3 shows a schematic sectional view of the pedestrian protection device according to the embodiment of the present invention in a state in the course of a collision.

4 FIG. 12 is a schematic sectional view of the pedestrian protection device according to the embodiment of the present invention in an unlocked state in collision with a high collision pulse that is greater than or equal to a threshold collision pulse. FIG.

5 schematically shows the pedestrian protection device according to the embodiment of the present invention in a locked state in a collision with a low collision pulse, which is smaller than the threshold collision pulse.

6 FIG. 12 is a schematic diagram showing a characteristic of an electric resistance of a collision detecting device of the pedestrian protection device according to the embodiment of the invention over time in collision with the high collision pulse and the low collision pulse. FIG.

The following is an embodiment of the present invention with reference to FIG 1 to 6 described.

A pedestrian protection device 1 is at a front end of a motor vehicle front end, in particular a Kraftfahrzeugbug, with a bumper cross member 3 arranged. The pedestrian protection device 1 has a deformation element 5 on, its deformation area 57 between a vehicle outer skin, that is a bumper cover 9 , and the bumper cross member 3 is trained.

How out 1 and 2 can be seen, has the deformation element 5 a first element 51 and a second element 52 , where the first element 51 in the second element 52 is movably mounted. The first element 51 has a substantially octagonal hollow cylindrical body. The second element 52 is fixed to the bumper cross member 3 mounted and has an opening which is substantially an outer periphery of the first element 51 equivalent. In particular, the opening is formed such that the first element 51 is displaceable within the opening. At the second element 52 are opposite two locking elements 53 movably mounted, each with a spring element 56 in the direction of the outer circumference of the first element 51 can be prestressed. The locking elements 53 are displaceable transversely to a vehicle longitudinal direction in / on the first element 51 stored. The first element 51 also has the locking elements 53 assigned contact surfaces 55 on, attached to the outer perimeter of the first element 51 are formed. The contact surfaces 55 extend obliquely to a deformation direction x of the deformation element 5 . which may coincide with a vehicle longitudinal direction. Further, in the outer periphery of the first element 51 the locking elements 53 associated wells 54 educated. In the idle state or initial state, ie in the unloaded state, of the deformation element 5 are the locking elements 53 on the outer periphery of the first element 51 on or at least almost. The spring elements 56 are in this position in a substantially relaxed, not biased state.

The pedestrian protection device 1 further comprises a collision detection device which detects a deformation of the deformation element 5 can capture. The collision detection device can via a resistance measurement 7 , which is a sensor device according to the invention, an electrical resistance between the locking element 53 and the first elements 51 measure up. In particular, the electrical resistance is lower when the locking element 53 with the first element 51 is in contact, and the electrical resistance is significantly higher when the locking element 53 and the first element 51 are not in contact.

The function of the deformation element 5 is below with reference to 3 . 4 . 5 and 6 described.

3 shows a state in which the motor vehicle is subject to a frontal collision, and thus a collision load, which is shown in the figures by an arrow, on the bumper fascia 9 on the first element 51 acts, which makes the first element 51 in the direction of the second element 52 and thus the bumper cross member 3 is moved. Here come the locking elements 53 with the associated contact surfaces 55 in contact. The contact surfaces 55 are in the direction of displacement of the first element 51 provided with a slope, so that by a cooperation between the locking elements 53 and the associated contact surfaces 55 the locking elements 53 be moved in the course of the displacement in the transverse direction and thus against the respective spring element 56 Press so that the spring elements 56 be biased. In 3 the state is shown in which the first element 51 so far in the second element 52 shifted is that the meanwhile prestressed locking elements 53 at the end of the associated contact surfaces 55 arrived.

In 4 is the deformation element 5 shown in the frontal collision of the motor vehicle, wherein the motor vehicle collides with higher relative speed, for example, from 15 km / h or 20 km / h, and with a collision opponent who has at least the mass of a pedestrian. In this case, a relatively high collision pulse acts on the deformation element 5 , The first element 51 is at high speed relative to the second element 52 moved, so starting from the in 3 shown position upon further displacement of the first element 51 , the locking elements 53 due to the inertia and damping effect of the spring elements 56 over the wells 55 jump and only after the wells 55 with the outer circumference of the first element 51 get in touch. The outer circumference of the first element 51 forms apart from a frictional force between the locking elements 53 and the outer periphery of the first element 51 no more obstacle, leaving a further shift of the first element 51 opposite the second element 52 takes place at a relatively low level of force. Thus, the deformation element acts 5 from the collision speed of about 15 km / h or 20 km / h in total over a longer deformation distance in favor of pedestrian protection "soft".

If the vehicle collides at the higher relative speed, for example from 15 km / h or 20 km / h, with a smaller object or a small animal that has a lower mass than a pedestrian, a smaller collision pulse and the locking elements act 53 are due to the lower displacement speed of the first element with the recesses 54 lock positively (see also below explanation with reference to 5 ).

In 5 is the deformation element 5 shown in the frontal collision of the motor vehicle, the motor vehicle with low relative speed, for example, under 20km / h or 15km / h, and with a collision opponent, such as another motor vehicle or a rigid barrier, head-on colliding with the collision opponent. In this case, a relatively small collision pulse acts on the deformation element 5 , The first element 51 is at low speed compared to the second element 52 moved, so starting from the in 3 shown position upon further displacement of the first element 51 , the locking elements 53 by the spring force in the corresponding recesses 55 engage and the locking elements 53 another shift of the first element 51 prevent this positive engagement. Depending on the size of the collision pulse, the collision load is then transferred to the underlying structure or a plastic deformation of the first element takes place 51 at a high level of force, whereby sufficient collision energy is absorbed. The deformation element 5 In particular, it is designed to operate at collision speeds of For example, less than 4 km / h can transmit a collision load without deformation on the crash structure. At a greater collision speed, however, which is not yet relevant for pedestrian protection, such as a speed between 4 km / h and 20 km / h, the deformation element 5 deformed at a certain load level, so that the deformation element 5 contributes to the reduction of collision energy, without, for example, behind the bumper cross member 3 existing components, such as a radiator, are damaged.

Thus, a conflict of objectives can be solved, on the one hand at very low collision speeds, a sufficiently high rigidity of the deformation element 5 or a sufficiently large deformation force level of the deformation element 1 requires and at a slightly higher collision speed ensures adequate pedestrian protection by a low deformation force level.

With reference to 6 is explained below a function of the collision detection device.

The collision detection device according to the invention acts in such a way that in the collision with the low collision pulse, the locking element 53 for a relatively short period of time, not with the first element 51 is in contact. As a result, the electrical resistance has a characteristic course insofar as the electrical resistance assumes a high value for a relatively short period of time. A course of electrical resistance (y-axis) over time (x-axis) in the case of low-speed frontal collision, ie the in 4 Case shown is in the diagram of 6 represented qualitatively by a dashed line.

In this case, it is a pedestrian protection not relevant or less relevant collision, because the motor vehicle collides with a low relative speed or the mass of the collision opponent is significantly lower than the mass of a pedestrian.

Furthermore, the collision detection device according to the invention acts in the collision with the high collision pulse such that the locking element 53 for a relatively long period of time, not with the first element 51 is in contact. As a result, the electrical resistance in this case has a characteristic course in that the electrical resistance assumes a high value for a relatively long period of time. A course of electrical resistance (y-axis) over time (x-axis) in the case of frontal collision at high speed, ie the in 5 Case shown is in the diagram of 6 qualitatively represented by a solid line.

In this case, it is a collision relevant to pedestrian protection, in which further pedestrian protection measures are to be initiated. Due to the course of the resistance measured by the sensor device, the collision detection device can detect whether it is a collision with a pedestrian or a collision with a relatively small collision pulse that is not relevant for pedestrian protection.

The pedestrian protection device 1 also has a control device that decides upon detection of a pedestrian protection relevant collision by the collision detection device to activate further pedestrian protection measures. For example, the controller activates an elevation of the front door into a pedestrian protection layer and / or inflation of a pedestrian protection airbag, such as a windshield airbag.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The 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

• EP 1386794 A1 [0004, 0005]

Claims (9)

Pedestrian protection device ( 1 ) for a motor vehicle with a cross member ( 3 ), in particular a bumper cross member, and a deformation element ( 5 ), which on the cross member ( 3 ), wherein the deformation element ( 5 ) a first element ( 51 ) and a second element ( 52 ), which are slidable relative to each other due to the collision, and a pretensioned or collision-type pretensionable locking element (US Pat. 53 ) attached to one of the first element ( 51 ) and the second element ( 52 ) is movably mounted and with the other of the first element ( 51 ) and the second element ( 52 ) is positively engageable in the course of a collision, wherein the pedestrian protection device a collision detection device with a sensor device ( 7 ) for detecting a position or a change in position of the locking element ( 53 ), wherein the collision detection device based on the position or the position change of the locking element ( 5 ) detects a collision state, in particular a collision pulse, of the motor vehicle. Pedestrian protection device according to claim 1, wherein the locking element ( 53 ) is designed such that, with a low collision pulse, which is smaller than a predetermined collision pulse, with a depression ( 54 ) or a step positively engages the deformation element ( 5 ) is deformable at a high load level, and that it is at a high collision pulse, which is equal to or greater than the predetermined collision pulse on the recess ( 54 ) or the step jumps and the deformation element ( 5 ) is deformable at a low load level. Pedestrian protection device according to claim 1 or 2, wherein the sensor device ( 7 ) is adapted, a locked position of the locking element ( 53 ) and / or an unlocked position of the locking element ( 53 ) capture. Pedestrian protection device according to one of the claims 1 to 3, wherein the sensor device ( 7 ), the position or the change in position of the locking element ( 53 ) based on a contact or a missing contact between the locking element ( 53 ) and the first element and the second element, respectively. Pedestrian protection device according to claim 4, wherein the sensor device ( 7 ), the position or the change in position of the locking element ( 53 ) on the basis of a time which the locking element ( 53 ) not in contact with the first element ( 51 ) or the second element ( 52 ). Pedestrian protection device according to one of the claims 1 to 5, wherein the sensor device ( 7 ) the position or the change in position of the locking element ( 53 ) due to an electrical resistance between the locking element ( 53 ) and the second element ( 51 ) or the first element ( 52 ) detected. Pedestrian protection device according to one of claims 1 to 6, further comprising a control device based on the position or the position change of the locking element ( 53 ) instructs active pedestrian protection measures, for example raising a front flap and / or triggering a pedestrian protection airbag. Pedestrian protection device according to one of the claims 1 to 7, wherein a deformation area ( 56 ) of the deformation element ( 5 ) between a body shell ( 9 ), in particular a bumper cover, and the cross member ( 3 ) is trained. Pedestrian protection device according to one of the claims 1 to 8, wherein the locking element ( 53 ) transversely, in particular perpendicular, can be prestressed to the displacement direction.

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