Patent Application
20190308578
The invention relates to a bumper arrangement for the front region of a passenger car and to a passenger car having such a bumper arrangement.
A bumper arrangement of the type in question is known for example from WO 2014/154630 A1. The known bumper arrangement has an upper and a lower load path. The upper load path is formed by upper longitudinal members and an upper crossmember and, in the event of a collision of the passenger car, bears the main part of the energy reduction. The lower load path is formed by lower longitudinal members and a lower crossmember. The lower crossmember is usually also known as a “lower stiffener” or as a “lower bumper stiffener”. The two crossmembers are covered by a bumper cover. The lower crossmember serves to stiffen the bumper cover in its lower region in particular when subjected to a force by a pedestrian as a result of an accident. In the event of a pedestrian's lower leg colliding with the bumper cover, the lower crossmember causes the pedestrian to be moved onto the hood of the passenger vehicle in a manner accelerated by an appropriate force and thus in a defined manner in the region of his lower leg.
The object of the invention is to further develop the known bumper arrangement.
This and other objects are achieved by a bumper arrangement, and a vehicle having the same, for the front region of a passenger car, having an upper load path, which has upper longitudinal members and an upper crossmember, and having a lower load path, which has lower longitudinal members and a lower crossmember. At least one spring element that is supported on the lower longitudinal member with a first end portion is provided in the connection region of the lower longitudinal member to the lower crossmember. A device is provided, with which, in the event of a collision of the passenger car, the direct connection between the lower longitudinal member and the lower crossmember is undoable. After the direct connection between the lower longitudinal member and the lower cross member has been undone, the spring element forms the support for the crossmember with a second end portion.
By providing at least one spring element in the lower load path in each case in the connection region of the lower longitudinal member to the lower crossmember, the spring elements have the effect that, in the event of a collision of the passenger car with a pedestrian, the pedestrian is deflected optimally in the direction of the hood of the passenger car. In the event of a collision, the pedestrian's torso is displaced in the direction of the hood. This inclined position of the torso is not followed to the same extent by the legs and, in particular, the lower legs of the pedestrian. The spring elements create a “rebound” according to the invention, with the result that the lower legs of the pedestrian are subjected to a force in the direction of travel of the passenger car and thus, in accordance with the inclined position of the torso, the lower legs are made to “follow suit”.
The connection regions of the lower longitudinal members to the lower crossmember are the front end portions of the lower longitudinal members or are deformation elements, known as “defoboxes”, provided at the front end portions of the lower longitudinal members. For reasons of linguistic simplification, in principle, whenever the expression “lower longitudinal member” is used in connection with the present patent application, the alternative of a deformation element arranged at the front end portion of the lower longitudinal member is also encompassed equally. Such deformation elements serve for energy reduction in that, in the event of a collision, they plastically deform before plastic deformation of the longitudinal member occurs.
Preferably, two spring elements are provided, which are arranged on the right and left, in each case in the connection region of the lower longitudinal members to the lower crossmember, such that, in the event of a collision, spring-elastic support of the entire lower crossmember with respect to the lower longitudinal members and thus with respect to the support structure of the passenger car is achieved with only two spring elements. Depending on whether the collision of the passenger car with the pedestrian occurs in the central region or in the region of a lateral end portion of the lower crossmember, both spring elements can support the crossmember in this case, or the support is provided only by one of the two spring elements.
In an advantageous configuration of the invention, the device for undoing the direct connection has at least one component that has a predetermined breaking point, such that, in the event of a collision, when a predetermined force level is exceeded, the component fails and the direct connection between the lower longitudinal member and lower crossmember is automatically undone. This embodiment is characterized by very high functional reliability and low costs. An additional energy source for actuating the component is not required. The failure of the component with the predetermined breaking point is designed for the collision with a pedestrian and for the force level that is achieved in standardized tests, for example with what is known as a FLEX-PLI (“Flexible Pedestrian Legform Impactor”). By contrast, the component with the predetermined breaking point is not intended to fail in the event of parking knocks and the like.
Of course, it is possible, rather than a component with a predetermined breaking point, to provide for example a pyrotechnically acting element or an electrically actuable element for undoing the connection, for example an electromagnetically movable locking bolt.
By way of example, the device for undoing the direct connection of the lower crossmember to the lower longitudinal member is in the form of a shear bolt that connects the lower longitudinal member (or the deformation element) to the lower crossmember unless, in the event of a collision, the connection is undone by the shear bolt breaking off and the lower crossmember can be supported on the spring element.
In a preferred configuration of the invention, the spring elements are embodied in a compressible manner, such that, in the event of a collision, when the spring elements are compressed, an additional deformation travel is available. This applies equally for spring elements with and without pretension, wherein, in the case of pretensioned spring elements, the available deformation travel may be somewhat reduced. As a result of the compression of the spring element, the latter absorbs additional spring energy.
According to one development of the invention, in order to limit the deformation travel, i.e. the distance by which the lower crossmember plunges counter to the direction of travel, a stop is provided on the lower longitudinal member. As soon as the stop is reached, the compressed spring element releases the absorbed energy again, with the result that the lower crossmember is accelerated forward in the direction of travel and thus a “rebound” that is as good as possible is exerted on the pedestrian's lower leg.
During normal operation of the passenger car (that is to say without the action of a force as a result of a collision), the spring elements can be relaxed or pretensioned. In the case of pretensioned spring elements, in the event of a collision, the energy stored in the spring elements is additionally available, in order to enhance the above-described advantageous effect with regard to the displacement of a pedestrian.
The arrangement, proposed in one configuration of the invention, of the spring elements in the interior of the lower longitudinal member is characterized by a particularly small space requirement. As already explained above, this is equivalent to the arrangement of the spring elements in the interior of deformation elements (“defoboxes”) that are arranged in each case at the front end portions of the lower longitudinal members.
The spring elements can consist of plastic or metal or of a combination of both materials. In one advantageous configuration of the invention, the spring elements are in the form of coil springs, and are thus cost-effective, functionally reliable and space-saving.
A passenger car having a bumper arrangement according to the invention is also disclosed.
All location information (for example front, rear) used herein relates to the direction of travel of the passenger car when traveling forward.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.
In the drawings, the direction of travel is labeled FR and a coordinate system with the spatial directions X (vehicle longitudinal direction), Y (vehicle transverse direction) and Z (vehicle vertical axis) is indicated. The X direction extends parallel to the direction of travel FR.
Provided in the deformation element 28 is a fork-like clearance 54 for displacement of the crossmember 22 counter to the direction of travel FR. This displacement occurs according to the invention in the event of a collision when a predetermined force level is exceeded and the shear bolt 50 breaks at its predetermined breaking points 56 under the action of the collision force. The predetermined breaking points 56 are in the form of reductions in cross section in the shank of the shear bolt 50. The force level from which the shear bolt 50 fails is adapted to the forces that arise in the event of a collision with a pedestrian. Once this force level has been exceeded, the shear bolt 50 breaks, and so the force acting on the pedestrian's lower leg T is limited in that an additional deformation travel S is now available, since, after the breaking off of the shear bolt 50, the lower crossmember 22 can move toward the rear counter to the direction of travel FR under the load of the collision, until the spring element 30 forms a solid block and/or the end wall 58 of the clearance 54 forms a stop.
Once this maximum intrusion has been reached, as the collision continues, the energy stored in the spring element 30 on account of the preceding collision-related compression (and possibly on account of the pretension already applied in the normal position of the spring element 30 according to
In order to further understand the invention, reference may be made to Applicant's U.S. application Ser. No. ______ (Atty Docket No. 080437.PC324US), incorporated by reference above.
The invention can be summarized as follows: a bumper arrangement 2 of a passenger car has an upper and a lower load path 10 and 20, respectively. Provided according to the invention on the crossmember 22 of the lower load path 20 is a spring element 30, which, in the event of a collision of a pedestrian with the passenger car, exerts an additional force on the pedestrian's lower leg T in order to support the movement of the pedestrian in the direction of the hood of the passenger car.
The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2016 226 096.0 | Dec 2016 | DE | national |
This application is a continuation of PCT International Application No. PCT/EP2017/084003, filed Dec. 21, 2017, which claims priority under 35 U.S.C. § 119 from German Patent Application No. 10 2016 226 096.0, filed Dec. 22, 2016, the entire disclosures of which are herein expressly incorporated by reference. This application contains subject matter related to U.S. application Ser. No. ______ (Atty Docket No. 080437.PC324US), entitled “Bumper Arrangement for the Front Region of a Passenger Car” filed on even date herewith, the entire disclosure of which is incorporated by reference herein.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/EP2017/084003 | Dec 2017 | US |
| Child | 16448631 | US |
